Phosphatidylinositol 3-kinase Inhibitor Research Articles

Abstract C045: Combinations of PI3K inhibitors with targeted oncology agents in multicellular spheroid models

Abstract Dysregulation of the phosphatidylinositol 3-kinase (PI3K) pathway plays a significant role in cancer, and inhibitors offer a promising strategy for targeted therapies. The selectivity of current inhibitors varies against different PI3K isoforms or subtypes. For example, alpelisib and inavolisib predominantly target the α-isoform, whereas duvelisib targets the δ- and γ-isoforms. By contrast, copanlisib is a pan-PI3K inhibitor, exhibiting activity against all isoforms. In combinations with other targeted agents, we investigated the activity of these four PI3K inhibitors against multicellular spheroids. The multicellular spheroids, grown from 60% malignant cells, 25% endothelial cells, and 15% mesenchymal stem cells, served as a model for human solid tumors that incorporates both malignant and stromal components. Thirty multicellular spheroid models were grown from various malignant cell types, including twenty-seven patient-derived cancer cell lines obtained from the NCI Patient-Derived Models Repository (https://pdmr.cancer.gov/) and three established cell lines from the NCI-60 human tumor cell line panel. After three days of spheroid growth, anticancer agents were introduced at concentrations up to their reported clinical Cmax value, if known. After seven days of drug exposure, cell viability was measured using the CellTiter-Glo 3D assay. Among the various drug combinations evaluated, simultaneous targeting of the PI3K and RAS pathways was highly effective, particularly against malignant cell lines with an activated RAS pathway. Notably, additive and/or synergistic activities were observed when either the α-isoform-specific PI3K inhibitors (alpelisib and inavolisib) or the pan-PI3K inhibitor (copanlisib) was combined with either the MEK inhibitor selumetinib, the ERK inhibitor ravoxertinib, or the type II pan-RAF kinase inhibitor DAY101. Additionally, combinations of the same three PI3K inhibitors with variant-specific inhibitors, such as vemurafenib (BRAF V600E), sotorasib (KRAS G12C), or MTRX-1133 (KRAS G12D) demonstrated selective activity against cell lines carrying the variant. Another effective combination with PI3K inhibitors was achieved with vertical inhibition of the PI3K pathway through the addition of the mTORC1/2 kinase inhibitor sapanisertib. Finally, combinations of a CDK4/6 inhibitor (abemaciclib or palbociclib) with a PI3K inhibitor demonstrated synergistic activities, although they were not as potent as other combinations. This project was funded in part with federal funds from the NCI, NIH, under contract no. HHSN261201500003I. Citation Format: Thomas S Dexheimer, Thomas Silvers, Nathan P Coussens, Rabih Said, Beverly A Teicher, James H Doroshow. Combinations of PI3K inhibitors with targeted oncology agents in multicellular spheroid models [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C045.

Porcine Acellular Dermal Matrix Promotes Migration and Suppresses Inflammation of Keratinocytes by Mediating the AKT Signaling Pathway.

Porcine acellular dermal matrix (pADM) is known to accelerate wound healing. However, the underlying molecular mechanism remains unclear. This study aimed to investigate the effects of pADM on wound healing and its underlying mechanisms. HaCaT cells were treated with hydrogen peroxide (H2O2) or pADM, and the appropriate treatment concentration was determined using the cell counting kit-8 and flow cytometry. Cell migration was assessed using a Transwell assay and scratch test. Inflammation was evaluated using enzyme-linked immunosorbent assay. Western blotting was performed to measure the levels of protein kinase B (AKT) pathway-related proteins. The results showed that H2O2 inhibited cell viability and induced apoptosis in a dose-dependent manner. pADM promoted cell migration and decreased the levels of interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in H2O2-treated HaCaT cells. Moreover, pADM rescued the downregulation of phosphorylated (p)-AKT and p-mechanistic target of rapamycin (mTOR) induced by H2O2. LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, abrogated migration and anti-inflammatory response caused by pADM. In conclusion, pADM promotes cell migration and inhibits inflammation by activating the AKT pathway under oxidative stress. These findings support the use of pADM for post-traumatic therapy and reveal a novel underlying mechanism of action.

The Novel CDK9/CDK4/6/PI3K Triple Inhibitor LCI139 for the Treatment of MYC-Driven Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive B cell malignancy with characteristic t(11;14)(q13;q32) translocation juxtaposing IGH and CCND1 gene loci. This chromosomal rearrangement leads to Cyclin D1 overexpression and cell cycle dysregulation at the G1/S phase transition. MCL is generally diagnosed at advanced stages and follows an aggressive course of disease. Although chemotherapy-based combination regimens are initially effective, most patients relapse with a median survival of only 2.5-5 years. While novel targeted therapeutics have shown promising activity in relapsed/refractory patients, inevitable relapse associated with progressively declining efficacy and increasing resistance to single agent targeted therapy is a major concern. To overcome this barrier, we designed in-silico based a novel multitarget small molecule inhibitor LCI139 which simultaneously blocks three oncogenic targets: cyclin-dependent kinase 9 (CDK9), CDK4/6, and phosphatidylinositol-3 kinase (PI3K). LCI139 is a potent CDK9/CDK4/6/PI3K inhibitor with IC 50s of 0.000039µM (CDK9), 0.0015µM/0.0036µM (CDK4/6) 0.070µM (p110α), 0.461µM (p110γ), and 0.214 (p110δ), as determined by cell free assay alpha screens. Dose-dependent screening of LCI139 against a panel of MCL cell lines revealed robust cytotoxic effects with maximal IC 50 of 86.67 nM in JeKo-1 cells, 64.8 nM in Mino cells, and 202.5 nM in Rec-1 cells. Compared with clinical single agent CDK9 inhibitor AZD4573, LCI139 is less toxic to normal human stromal cells (HS-5), whereas both LCI139 and AZD4573 have no significant cytotoxic effect on normal human foreskin fibroblast cells (Hs68). LCI139 treatment at various concentrations for 24hrs induced significant apoptotic response in two MCL cell lines, JeKo-1 (p<0.001 DMSO vs LCI139 100 nM, p<0.0001 DMSO vs LCI139 200 nM) and Mino (p<0.05 DMSO vs LCI139 100 nM, p<0.0001 DMSO vs LCI139 200 nM) as determined by Annexin V/7-AAD apoptosis staining. Similarly, LCI139-induced apoptotic cell death was further confirmed by increasing cl-PARP protein levels compared to control as assessed by Western blot analysis. LCI139 induced robust G2/M cell cycle arrest in JeKo-1 cells and G1 arrest in Mino cells. The mechanism of action of pan-CDK inhibitors has been associated with downregulation of the anti-apoptotic protein MCL-1 through inhibition of transcriptional CDKs. Our results show that short-term exposure of LCI139 (1hr and 3hr) significantly suppressed MCL-1 and MYC mRNA expression in JeKo-1 (p<0.00001 DMSO vs LCI139) and Mino cells (p<0.00001 DMSO vs LCI139). LCI139 suppressed pRpb1 (Ser2), MCL-1 and cMYC protein expression in IgM-stimulated JeKo-1 and Mino cells in a dose-dependent manner. Treatment with LCI139 had no significant effect on pAKT (Ser473) in Jeko-1 cells, whereas pAKT (Ser473) was completely abolished in Mino cells at 500nM of LCI139. Mechanistically, our findings also demonstrate that LCI139 decreased MCL-1 and cMYC protein stability and reduced half-life as accessed by cycloheximide chase assay. This decrease in cMYC stability is associated with decreased of cMYC phosphorylation at Ser62. Adaptive kinome remodeling via drug-induced transcriptional reprogramming is a known contributor to ibrutinib resistant (IR) MCL. RNA-sequencing analysis of JeKo-1 vs Jeko-1 IR cells revealed a total of 3468 differentially expressed genes (FC > 1.5 and FDR < 0.05) where 110 kinases display altered expression in JeKo-1 IR cells. Finally, we show that LCI139 overcomes chronic ibrutinib resistance by decreasing viability in JeKO-1 IR and Mino IR cells with an IC 50 of 79 nM and 89 nM, respectively. Therefore, the multitarget small molecule inhibitor LCI139 has superior potency against IR MCL cell lines and overcomes ibrutinib-resistance at nanomolar doses.

PI3Kδ Inhibitor Linperlisib As a ≥ 3-Line Treatment for Relapsed or Refractory Follicular Lymphoma: A Subgroup Analysis of a Phase II, Single-Arm, Open-Label Trial

Introduction Follicular lymphoma (FL) is the most common subtype of indolent non-Hodgkin lymphoma (NHL), originating in follicular central B cells, and accounts for approximately 22% of all newly diagnosed cases of NHL. Chemo-immunotherapy is the standard treatment option for FL. Unfortunately, the progression of the disease to relapsed or refractory FL (r/r FL) is still inevitable, which raised concern about subsequent effective treatments. Several δ isoform of phosphatidylinositol 3-kinase (PI3K-δ) inhibitors have ever been approved for r/r FL after ≥2 lines of prior therapies. However, most of their indications for r/r FL were withdrawal for increased risk of death and serious side effects. The latest data from the Chinese phase II clinical trial of linperlisib (Trial registration ID: NCT04370405), a novel oral PI3Kδ-selective inhibitor, in patients with r/r FL who had received at least two systemic therapies were presented. In this trial, linperlisib demonstrated compelling efficacy and was generally well-tolerated in the treatment of r/r FL patients after ≥2 prior systemic therapies. Linperlisib was approved by China National Medical Products Administration (NMPA) for adult r/r FL previously treated with at least two system therapies in November 2022. The ≥3 lines of treatment options are still unmet for the r/r FL. In this setting, this subgroup analysis of the linperlisib phase II trial aimed to evaluate outcomes of linperlisib in later-line treatment of r/r FL. Methods This study included all the patients with r/r FL who had received at least two systemic therapies previously enrolled in the open-label, single-arm, phase II trial (linperlisib, 80mg, po, q.d., in a 28-day cycle), with overall response rate (ORR) as the primary endpoint. In this subgroup analysis, the patients were divided into two groups according to the treatment lines they received: >3 prior lines of treatment and ≤3 prior lines of treatment. All of the statistical analyses were descriptive. Results A total of 84 r/r FL patients from 25 sites in China from April 2019 to September 2020 were enrolled in this trial, with a cutoff date of September 30, 2021. The ORR was 79.8%, with statistical significance in a heavily pretreated FL patient population with a median of 4 prior therapies, with a well-tolerated safety profile. A total of 43 patients received >3 prior lines of treatment, while 41 patients received ≤3 prior lines of treatment. The median age between the two groups was similar (range: 29.0 - 78.0, 52.0 years for >3 prior lines vs. 48.0 years for ≤3 prior lines). The majority of patients had Ann Arbor staging III-IV (40 for >3 prior lines vs. 34 for ≤3 prior lines). The median number of prior regimens was 4 for >3 prior lines and 3 for ≤3 prior lines. Overall, there were 67 patients achieved responses, with ORR of 83.7% (36, 95%CI:69.3, 93.2) for >3 prior lines vs. 75.6% (31, 95% CI: 59.7, 87.6) for ≤3 prior lines based on independent review committee assessment. Compared with patients who received ≤3 prior lines, patients received ≤3 prior lines achieved higher disease control rate (41[95.3] vs. 37 [90.2%]). The median DOR was 12 months (95% CI: 7.3, 15.9) for >3 prior lines vs. 13 months (95% CI: 9.2, NE). The median PFS was 11.9 months (95% CI: 9.1,19.4) for >3 prior lines vs. 13.3 months (95% CI: 8.2, NE) for ≤3 prior lines. The OS of both groups was not reached. The most common treatment-related adverse events (≥20%, TRAEs) were neutropenia (21 [48.8%] for >3 prior lines vs. 18 [43.9%] for ≤3 prior lines), leukocyte count decreased (15 [34.9%] vs. 15 [36.6%]), alanine aminotransferase increased (10 [23.3%] vs. 9 [22.0%]), lymphocyte count decreased (9 [20.9%] vs. 5 [12.2%]), hypertriglyceridemia (9 [20.9%] vs. 11 [26.8%]), and hypercholesteremia (6 [24.0%] vs. 7 [11.9%]). The most common grade ≥3 TRAEs (≥10%) were neutropenia (9 [20.9%] vs. 4 [9.8%]), pulmonary inflammation (3 [7.0%] vs. 6 [14.6%]), infectious pneumonia (2 [4.7%] vs. 5 [12.2%]). Conclusions This subgroup analysis revealed that linperlisib could achieve benefit in r/r FL patients who received at least 2 prior system therapies regardless of treatment lines. The AEs were well-tolerated. Further trials with large-scale samples were warranted.

A Systematic Literature Review (SLR) and Meta-Analysis of Clinical Evidence of Second Line or Later (2L+) Treatments for Follicular Lymphoma (FL) in Adult Patients

Background:First-line (1L)standard of care (SOC) options for patients with FL include an anti-CD20 monoclonal antibody with or without chemotherapy, and second-line (2L) therapeutic options are similar to 1L. There is no defined SOC for patients who require treatment in third, fourth, and later lines of therapy (LOT). Additionally, patients with high-risk FL who relapse ≤ 24 months after frontline treatment (POD24) have limited treatment options that can provide a durable response. Recently, novel treatments such as CAR T cell therapies and T cell engager regimens have been shown to improve efficacy outcomes in third line or later (3L+) and POD24 populations. We conducted an SLR of all relevant clinical evidence to evaluate the efficacy and safety of available therapies used in the treatment of adult patients with R/R FL in 3L+, fourth line or later (4L+), and 2L+ POD24 settings. We also aimed to conduct meta-analyses to derive pooled effect estimates for response and survival outcomes in these settings. Methods: Publications from 01/01/1998 to 09/17/2022 were identified using Ovid MEDLINE ®, Embase, and Cochrane Central Register of Controlled Trials, with supplemental hand searches of key conferences and bibliographies of recent relevant SLRs. Study eligibility was assessed according to prespecified population, intervention, comparator, outcome, and study design criteria. Studies were eligible if they were in English and enrolled patients with R/R FL (grade 1‒3A) in 3L+, 4L+, and POD24 settings. Eligible treatments included CAR T cell therapies (axicabtagene ciloleucel, lisocabtagene maraleucel, and tisagenlecleucel), T cell engagers (mosunetuzumab, glofitamab, epcoritamab, odronextamab), phosphatidylinositol 3-kinase (PI3K) inhibitors (copanlisib, duvelisib, idelalisib), HSCT, yttrium-90 (90Y) ibritumomab tiuxetan, tazemetostat, and conventional therapies (immunochemotherapies, single- or multiagent chemo- or immunotherapies, and alkylating agents). Outcomes of interest were OS, PFS, ORR, CR rate, PR, duration of response, and time to next treatment. Independent review committee (IRC) data were extracted when both IRC- and investigator-assessed data were reported. Pooled estimates for ORR, CR rate, OS, and PFS across all treatments were calculated among 3L+, 4L+, and POD24 patient populations. For POD24 studies, we combined POD24 definitions (ie, definitions with respect to POD24 from frontline therapy or baseline) and POD24 patients across LOTs (ie, presenting in 2L+). For each outcome in 3L+, 4L+, and POD24 settings, ≥ 4 sufficiently similar studies were required for a meta-analysis to be deemed feasible. Results: Of 5250 records screened, 112 were included, representing 60 unique studies. Of 60 studies, 33 (55%) were retrospective or prospective observational, while 27 (45%) were clinical trials (randomized, nonrandomized, and single arm). There was significant heterogeneity in patient populations and baseline characteristics across studies. Most studies (n = 48; 80%) reported findings for 3L+ FL, with limited evidence for 4L+ and POD24 patients. Results for ORR, CR rate, PFS, and OS by treatment type across 3L+, 4L+, and POD24 patients are presented in Table 1. ORR and CR rate data were highly variable depending on treatment used and length of follow-up period in the study. Across 3L+, 4L+, and POD24 patients, the highest ORR and CR rate ranges were observed for CAR T cell therapies, T cell engagers, and HSCT. Median PFS was highest for HSCT, T cell engagers, and CAR T cell therapy in the 3L+ setting and was not reported or not reached for HSCT and T cell engagers in 4L+ and POD24 settings. Median OS was not reached for patients receiving T cell engagers in the 3L+ setting or those receiving CAR T cell therapy in the 3L+, 4L+, and POD24 settings. Various meta-analyses including all treatments were considered feasible for 3L+, 4L+, and POD24 populations (Table 2). For ORR and CR rate in the 3L+ population, sensitivity analyses excluding CAR T cell therapies, T cell engager regimens, and HSCT were feasible and showed lower ORR and CR rate when these therapies were removed. Conclusions: This SLR demonstrated an evolving FL treatment landscape, with new agents such as CAR T cell therapies and T cell engagers exhibiting potential for improving effectiveness of treatment for patients in 3L+, 4L+, and 2L+ POD24 populations.

A Phase II Study of Intermittent Duvelisib Dosing in Patients with Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL)

Background. Targeting phosphatidylinositol 3-kinase (PI3K) has emerged as an efficacious approach for treatment of chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). However, toxicities of the PI3K inhibitors are an important concern limiting their use. Duvelisib is a potent oral inhibitor of both the PI3K-δ and PI3K-γ isoforms with proven efficacy in CLL/SLL. Here we report the results of a phase 2 study evaluating efficacy and safety of duvelisib with intermittent dosing in patients with relapsed/refractory CLL/SLL Methods. This open-label, single arm, phase 2 study enrolled patients with CLL/SLL treated with at least 1 prior line of therapy with active disease as defined by the iWCLL 2008 criteria. Duvelisib was given at a dose of 25 mg PO BID for 28-day cycles for a total of 12 weeks during the induction phase, followed by 75 mg PO BID 2 days on and 5 days off for repeated 28-day cycles during the maintenance phase until death, intolerance or disease progression. The primary endpoint was progression free survival (PFS) at 12 months; secondary endpoints were safety and clinical benefit. The trial was originally planned to enroll 27 patients but was stopped early due to difficulties with enrollment following changing FDA guidance for the use of PI3K inhibitors. Results. Fifteen patients were enrolled. Median age was 74 (59-82) years, 8/15 (53%) were female; patients were primarily Caucasian (13/15; 87%); performance status was 0-1, with 27% (4/15) ECOG 0 and 73% (11/15) ECOG 1. This was a heavily pre-treated patient population with a median of 3 prior lines of therapy (1-6). Among patients where results were available, 79% (11/14) had abnormal FISH results including 36% with TP53 gene loss, 27% del(13q), and 18% del(11q). Sixty-seven percent (8/12) had unmutated IGHV. Of the 15 patients treated, 4 were not evaluable for efficacy due to coming off study early for toxicity (2), development of MDS unrelated to study drug (1) or death due to complications from COVID-19 infection (1). Among the 11 efficacy-evaluable patients, 82% achieved PR, and 18% had stable disease. The 12-month PFS was 43% (95%CI: 18%-66%) and the median PFS was 9.9 months (95% CI: 5.5-NA). Among the 9 responders, the median duration of response (DOR) was 5.3 months (95%CI: 1.9-NA) and 12-month DOR was 22% (95%CI:3%-51%). Five patients (33%) discontinued therapy due to adverse events, which occurred during the induction phase in 4/5 of the patients. Five patients (33%) discontinued due to progressive disease - all during the maintenance phase of treatment. Additionally, 2 patients discontinued due to MD decision; one patient developed MDS which was unrelated to duvelisib; one patient died during treatment due to complications from COVID-19. Treatment was generally well tolerated with the most common grade 3 or higher adverse events being leukocytosis (20%), alanine aminotransferase (ALT) increase (13%), aspartate aminotransferase (AST) increase (13%), oral mucositis (13%) and colitis (13%). The adverse events leading to treatment discontinuation occurred primarily during induction. The most common adverse events of any grade included fatigue in 5 patients (33%), leukocytosis, vomiting, ALT increase, AST increase, diarrhea, and elevation of alkaline phosphatase, which occurred in 4 patients each (27%). Conclusions. We report the results of an open-label, phase 2 study utilizing a continuous dosing induction phase followed by an intermittent dosing maintenance phase of the PI3K inhibitor duvelisib in patients with relapsed/refractory CLL/SLL. Patients who received duvelisib on an intermittent schedule achieved some clinical benefit, however, the desired 12-month PFS goal of 50% was not reached. Adverse events in general were manageable and mainly related to gastrointestinal and liver toxicity, and patient died during treatment from complications from COVID-19 pneumonia. After an initial 12 weeks of continuous duvelisib treatment, the incorporation of intermittent dosing appears to be a viable option for patients with previously treated CLL/SLL.

Interfering TRIB3 protects the blood brain barrier through PI3K/Akt pathway to alleviate cerebral ischemia-reperfusion injury in diabetes mellitus mice

This study aimed to treat diabetic cerebral ischemia-reperfusion injury (CI/RI) by affecting blood brain barrier (BBB) permeability and integrity. The CI/RI model in DM mice and a high glucose (HG) treated oxygen and glucose deprivation/reoxygenation (OGD/R) brain endothelial cell model were established for the study. Evans blue (EB) staining was used to evaluate the permeability of BBB in vivo. TTC staining was used to analyze cerebral infarction. The location and expression of tribbles homolog 3 (TRIB3) in endothelial cells were detected by immunofluorescence. Western blotting was used to detect the protein expressions of TRIB3, tight junction molecules, adhesion molecules, phosphorylated protein kinase B (p-AKT) and AKT. The levels of pro-inflammatory cytokines were detected by qRT-PCR. Trans-epithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran were used to measure vascular permeability in vitro. TRIB3 ubiquitination and acetylation levels were detected. Acetyltransferase bound to TRIB3 were identified by immunoprecipitation. TRIB3 was localized in cerebral endothelial cells and was highly expressed in diabetic CI/R mice. The BBB permeability in diabetic CI/R mice and HG-treated OGD/R cells was increased, while the junction integrity was decreased. Interference with TRIB3 in vitro reduces BBB permeability and increases junction integrity. In vivo interfering with TRIB3 reduced cerebral infarction volume, BBB permeability and inflammation levels, and upregulated p-AKT levels. The phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin reversed the effects of TRIB3-interfering plasmid. In vitro HG treatment induced TRIB3 acetylation through acetyltransferase p300, which in turn reduced ubiquitination and stabilized TRIB3. Interfering TRIB3 protects BBB by activating PI3K/AKT pathway and alleviates brain injury, which provides a new target for diabetic CI/RI.

Tsantan Sumtang, a traditional Tibetan medicine, protects pulmonary vascular endothelial function of hypoxia-induced pulmonary hypertension rats through AKT/eNOS signaling pathway

Ethnopharmacological relevanceTsantan Sumtang (TS), originated from the Four Tantras, is an empirical Tibetan medicine prescription, which has been widely used for treating cardiovascular diseases in the clinic in Qinghai Province of China. Our previous studies found that TS alleviated hypoxia-induced pulmonary hypertension (HPH) in rats. However, the effect and bioactive fractions of TS on hypoxia-injured pulmonary vascular endothelium are unknown. Aim of the studyTo investigate the effect, bioactive fractions and pharmacological mechanism of TS on hypoxia-injured pulmonary vascular endothelium in vivo and in vitro. Materials and methodsIn vivo studies, HPH animal model was established, and TS was administrated for four weeks. Then, hemodynamic indexes, ex vivo pulmonary artery perfusion experiment, morphological characteristics, nitric oxide (NO) production, and the protein expression of protein kinase B (AKT)/endothelial nitric oxide synthase (eNOS) and AMP-activated protein kinase (AMPK)/eNOS signaling were determined. In vitro studies, 1% O2-induced pulmonary artery endothelial cells (PAECs) injury model was applied for screening bioactive fractions of TS by cell proliferation assay and NO production measurement. The associated proteins of AKT/eNOS signaling were further measured to elucidate underlying mechanism of bioactive fraction of TS via using phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002. Ultra-high performance liquid chromatography with hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS) was used to reveal the chemical profile of bioactive fraction of TS. ResultsTS showed protective effect on the integrity of distal pulmonary arterial endothelium in HPH rats. Tsantan Sumtang dilated pulmonary arterial rings in HPH rats. TS enhanced NO bioavailability in lung tissue via regulating AKT/eNOS signaling. Furthermore, in the cellular level, cell viability as well as NO content of hypoxia-injured PAECs were elevated by fraction 17 of water extract of TS (WTS), through activating the AKT/eNOS signaling. Ellagic acid could be one of compositions in fraction 17 of WTS to produce NO in hypoxia-injured PAECs. ConclusionTS restored pulmonary arterial endothelial function in HPH rats. The bioactive fraction 17 was screened, which protected hypoxia-injured PAECs via upregulating AKT/eNOS signaling.

Attenuated AKT signaling by miR-146a-5p interferes with chicken granulosa cell proliferation, lipid deposition and progesterone biosynthesis

Steroid hormones play a crucial role in the growth and maturation of poultry ovarian follicles, with progesterone secretion by granulosa cells (GC) being essential. According to our previous transcriptome analysis, it apparented that miR-146a-5p expressions were upregulated in the follicles undergoing atresia. In this study, we delved the depth to explore the underlying mechanisms by miR-146a-5p in the regulation of follicle functions in chicken. The study demonstrated that miR-146a-5p suppressed cell growth, lipids accumulation, and progesterone biosynthesis in chicken GC. Through targeting association validations, we identified delta 4-desaturase, sphingolipid 1 (DEGS1) as capable of interacting with miR-146a-5p. Co-transfection experiments further confirmed that DEGS1 reversed the impairment of GC functions by miR-146a-5p. Moreover, we discovered that miR-146a-5p suppressed AKT phosphorylation, while DEGS1 enhanced AKT phosphorylation. Phosphatidylinositol-3 kinase (PI3K) inhibitor (LY294002) studies showed that miR-146a-5p would inhibit AKT phosphorylation by governing the DEGS1/AKT pathway, which in turn regulates GC function. In summary, the findings revealed that miR-146a-5p suppressed cell growth, lipid deposition, and progesterone biosynthesis via the DEGS1/AKT pathway. These results may further enrich our understandings of how non-coding RNA regulates productive performance in chickens.

PTPRH promotes the progression of non-small cell lung cancer via glycolysis mediated by the PI3K/AKT/mTOR signaling pathway

BackgroundThe protein tyrosine phosphatase H receptor (PTPRH) is known to regulate the occurrence and development of pancreatic and colorectal cancer. However, its association with glycolysis in non-small cell lung cancer (NSCLC) is still unclear. In this study, we aimed to investigate the relationship between PTPRH expression and glucose metabolism and the underlying mechanism of action.MethodsThe expression of PTPRH in NSCLC cells was evaluated by IHC staining, qRT‒PCR and Western blotting. The effect of PTPRH on cell biological behavior was evaluated by colony assays, EdU experiments, Transwell assays, wound healing assays and flow cytometry. Changes in F-18-fluorodeoxyglucose (18F‐FDG) uptake and glucose metabolite levels after altering PTPRH expression were detected via a gamma counter and lactic acid tests. The expression of glycolysis-related proteins in NSCLC cells was detected by Western blotting after altering PTPRH expression.ResultsThe results showed that PTPRH was highly expressed in clinical patient tissue samples and closely related to tumor diameter and clinical stage. In addition, PTPRH expression was associated with glycometabolism indexes on 18F-FDG positron emission tomography/computed tomography (PET/CT) imaging, the expression level of Ki67 and the expression levels of glycolysis-related proteins. PTPRH altered cell behavior, inhibited apoptosis, and promoted 18F-FDG uptake, lactate production, and the expression of glycolysis-related proteins. In addition, PTPRH modulated the glycometabolism of NSCLC cells via the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, as assessed using LY294002 and 740Y-P (an inhibitor and agonist of PI3K, respectively). The same results were validated in vivo using a xenograft tumor model in nude mice. Protein expression levels of PTPRH, glycolysis-related proteins, p-PI3K/PI3K and p-AKT/AKT were measured by IHC staining using a subcutaneous xenograft model in nude mice.ConclusionsIn summary, we report that PTPRH promotes glycolysis, proliferation, migration, and invasion via the PI3K/AKT/mTOR signaling pathway in NSCLC and ultimately promotes tumor progression, which can be regulated by LY294002 and 740Y-P. These results suggest that PTPRH is a potential therapeutic target for NSCLC.Graphical

Combination of CDK4/6 Inhibitor Palbociclib and PI3K Inhibitor Idelalisib Synergistically Induces an Anti-Tumor Effect in B-Cell Lymphoma and Overcomes Ibrutinib Resistance

Introduction: Aberrant activity of cyclin-dependent kinases 4/6 (CDK4/6) is frequently detected in B-cell non-Hodgkin's lymphoma (B-NHL), indicating the therapeutic implications of CDK4/6 inhibitors for B-cell malignancies. What's more, the introduction of agents targeting B cell receptor signaling, especially phosphatidylinositol 3-kinase (PI3K) isoform-specific inhibitors, is rapidly changing how B cell malignancies are treated. In this study, we aim to investigate whether the combination of CDK4/6 inhibitor palbociclib (PAL) and PI3Kδ inhibitor idelalisib (IDE) has synergistic anti-tumor effects in B cell lymphoma. Besides, we also evaluated the effect of co-administration PAL and IDE in Bruton's tyrosine kinase inhibitor (BTKi) resistant model. Methods: In vitro, cell viability was analyzed using Cell Titer-Glo ®️ Luminescent Cell Viability Assay. Flow cytometry was used to detect apoptosis and cell cycle arrest induction. Western Blotting analysis was used to detect the changes in essential proteins in related signaling pathways. We also conducted RNA-seq to evaluate the whole transcriptome changes brought by co-treatment with PAL and IDE. The synergistic anti-tumor effects of PAL and IDE were also evaluated in vivo. BTKi secondary resistant cell lines were generated by long-time exposure to ibrutinib and BTK C481S mutation cell line was conducted by lentivirus infection and puromycin selection. Results: Firstly, we analyzed diffuse large cell lymphoma (DLBCL) gene expression profile results from GEO database, and there were more than 50% patients carried cell cycle-related genes alterations, especially for CDKN2A-CDK4/6/CCND1-Rb machinery. Then, it was noteworthy that the high level of CDK4/6 mRNA and protein expression correlated with worse survival of DLBCL patients. Next, we illustrated that pharmacological inhibition of CDK4/6 kinase activity induced inhibition of cell proliferation, tumor cell apoptosis, and cell senescence. Meanwhile, PAL treatment upregulated the expression of PI3Kδ, p-AKT (S473), and p-mTOR (S2448), suggesting compensatory activation of the PI3K-AKT-mTOR signaling pathway. Thus, combination treatment of PAL and PI3K inhibitor IDE was assessed, and this combination synergistically induced a more potent anti-proliferative effect in several B-NHL cell lines, including mantle cell lymphoma cell lines (Z-138 and Jeko-1), DLBCL cell lines (U2932 and OCI-Ly8) and Burkitt lymphoma cell line (Raji). Meanwhile, co-administration treatment could also trigger synergistic anti-tumor activity in BTK inhibitor ibrutinib-resistant HBL-1 BTK C481S and HBL-1 IR cells (long time exposure to ibrutinib). Next, the flow cytometry results indicated that the B-NHL cells became apoptotic after the PAL and IDE treatment. The activation of apoptosis-related proteins (cleaved-caspase3 and cleaved-PARP) and decrease of anti-apoptosis proteins expression (BCL-2, BCL-xL, XIAP, and MCL-1) were induced by combination of CDK4/6 and PI3K inhibitor treatment. The combination of PAL and IDE also substantially increased the cell population of G0/G1 phase and elevated expression of CDK4, CDK6, and CyclinD1. Furthermore, the gene expression profile analysis demonstrated that the mRNA expression level of PLK1 was significantly decreased by co-administration treatment, rather than in PAL or IDE treatment alone. Finally, the combination treatment also showed synergistic anti-tumor activity in multiple tumor-bearing mice models. Conclusion: The combination of CDK4/6 inhibitor palbociclib and PI3K inhibitor idelalisib synergistically induced anti-tumor activity in B-cell lymphoma through downregulation of PLK1 expression, suggested a new combination direction for the treatment of B-NHL and even BTK inhibitor-resistant patients.

Pooled Exposure-Response (ER) and Quantitative Benefit/Risk (B/R) Analyses Support the Approved Copanlisib Intermittent Dosing Regimen

Introduction: Copanlisib is a potent and highly selective pan-class phosphatidylinositol 3-kinase (PI3K) inhibitor with preferential activity against the p110α and p110δ isoforms. Unlike other PI3K inhibitors, copanlisib is uniquely administered intravenously using an intermittent schedule, supported by preclinical data and literature model-based analyses showing high tumor residence and time intervals enabling for recovery of normal tissue. The pivotal studies, CHRONOS-1 and CHRONOS-3, established the benefit/risk of copanlisib 60 mg on Day 1, 8, 15 of 28-day cycle as monotherapy in 3L+ relapsed follicular lymphoma and in combination with rituximab in 2L+ non-Hodgkin's lymphoma, respectively. While prior ER analyses in CHRONOS-1 suggested a positive ER trend for copanlisib safety, similar to oral continuously dosed PI3K inhibitors (2022 FDA ODAC), ER analyses from the larger Phase 3 study, CHRONOS-3, revealed no significant ER for safety (Morcos et al. CPT Pharmacometrics Syst Pharmacol 2023). This analysis investigates pooled ER relationships for copanlisib safety across the pivotal studies and considers them in the context of the ER for efficacy in CHRONOS-3, as part of a quantitative B/R analysis for the approved copanlisib intermittent dosing regimen. Methods: Individual static and time-varying exposure metrics in CHRONOS-1 and CHRONOS-3 were derived from a previously established comprehensive population pharmacokinetics (popPK) analysis (Morcos et al. CPT Pharmacometrics Syst Pharmacol 2023). ER analyses investigated the relationship to the efficacy endpoint: progression-free survival (PFS) in CHRONOS-3 using 2-year follow-up; and to the safety endpoints: time-to-first Grade ≥ 3 adverse events (Gr≥3 AEs) and serious adverse events (SAEs), and frequency of individual AEs associated with copanlisib treatment (hyperglycemia, diarrhea, hypertension, nausea, fatigue, neutropenia, and lung infections of any grade), pooled across CHRONOS-1 using 6-year follow-up and CHRONOS-3 using 2-year follow-up. Multivariate parametric time-to-event (TTE) and logistic regression models investigated ER relationships at a prespecified significance level of p<0.01 after accounting for other potentially prognostic demographic, laboratory, and disease related baseline covariates. To quantitatively assess the B/R of the copanlisib 60 mg intermittent dosing regimen, a clinical utility index (CUI) function was defined with a 1:1 weighting for efficacy and safety to consider the tradeoffs between any identified ER relationships for efficacy and safety. Results: In CHRONOS-3, the parametric TTE ER analysis for PFS was characterized by a 2-knot spline baseline hazard function and demonstrated a statistically significant positive ER relationship (p<0.00001). Analysis results are consistent with a prior ER analysis using a semi-parametric Cox proportional hazards model of earlier 1-year follow-up (Morcos et al. CPT Pharmacometrics Syst Pharmacol 2023). Therefore, greater copanlisib exposure is associated with more prolonged PFS. Across pooled CHRONOS-1 and CHRONOS-3, parametric TTE for first Gr≥3 AEs and SAEs were characterized by 2-knot spline baseline hazard functions and demonstrated a borderline significant ER for Gr≥3 AEs (p=0.014) and no significant ER for SAEs (p=0.26). Multivariate logistic regression analyses showed no significant ER for individual AEs after adjusting for relevant baseline covariates. Across the range of exposures achieved with the copanlisib 60 mg intermittent dosing regimen, a steeper relationship for the hazard ratio relative to placebo in is seen for the significant ER of PFS compared with the borderline ER of Gr≥3 AEs (Figure 1). The CUI accounting for the quantitative ER relationships confirmed the favorable B/R across the range of copanlisib exposures. Thus, lower copanlisib doses may result in lower efficacy while not necessarily resulting in substantially improved safety. Conclusions: The completed quantitative analyses substantiate the favorable B/R for the copanlisib 60 mg on days 1, 8, and 15 of a 28-day cycle dosing regimen.

Safety Results of a Phase I Study of Zandelisib + R-CHOP in Newly Diagnosed Diffuse Large B Cell Lymphoma (DLBCL)

Introduction: Emerging data have identified distinct genetic subtypes of DLBCL based on the diverse oncogenic molecular drivers with varying clinical outcomes when treated with standard R-CHOP. Relapse post frontline treatment could be curbed by integrating novel agents upfront. The phosphatidylinositol 3 kinase (PI3K) signalling pathway contributes to the oncogenesesis of both germinal center derived and activated B-cell (ABC) DLBCL subtypes (Wright, et al Cancer Cell, 2020). Zandelisib, a highly selective oral PI3Kδ inhibitor has proven efficacy in B cell lymphoma with a favorable toxicity profile when administered in intermittent dosing schedule (Pagel, et al Lancet Oncol 2022). We conducted a phase I/2 trial to evaluate the safety and efficacy of zandelisib in combination with R-CHOP chemotherapy in newly diagnosed DLBCL. The study enrollment was closed in 12/2022 after the development of zandelisib was discontinued. We present the results of the phase I (P1) trial. Methods: In this investigator-initiated trial, patients (pts) with untreated DLBCL with ECOG performance status (PS) ≤ 2, adequate bone marrow (BM) and organ function were enrolled from 08/2021-12/2022 at Cleveland Clinic (NCT04517435). ECOG PS 3 was allowed if it was attributed to the lymphoma diagnosis. The study was supported by the MEI Pharma. The P1 study had 2 dose escalation cohorts in combination with standard doses of R-CHOP every 21 days for 6 cycles; zandelisib was dosed 60 mg daily on days 1-4 in cohort 1 and daily on days 1-7 in cohort 2. If the 3 subjects in dose level 1 (D1) did not experience any dose limiting toxicity (DLT) during cycle 1 (C1), pts were enrolled into D2. In phase 2 (P2), a cycle of R-CHOP prior to the study treatment was allowed, if clinically deemed. All pts received pneumocystis jirovecii (PJP) and viral prophylaxis. Disease response was assessed after C3 and C6. Primary end point for P1 was to assess safety and tolerability of the combination and to determine recommended P2 dose (RP2D) of zandelisib. Pts who received at least 1 cycle of study treatment were included in the safety analysis. Primary objective of P2 is progression free survival (PFS) at 1 year. Pt and disease characteristics were analyzed using descriptive statistics. Results: We enrolled a total of 13 pts (P1: 9 and P2: 4) in the study prior to termination. The median age was 67 (range 46-79) years, with majority being female (53.8%), with an ECOG PS of 0-2 (100%). Most pts had stage III-IV disease 10/13 (77%), IPI ≥3 in 8/15 (62%), elevated LDH 9/13 pts (69%), and extranodal involvement 7/13 (54%). 3 pts had BM involvement. DLBCL was germinal center (GC) subtype in 77% of the pts. FISH studies revealed translocations in BCL2 (46%), BCL6 (8%) and c-myc (0%). There was no DLT observed in cohort 1 and zandelisib 60 mg daily on D1-7 was the RP2D. 12 of 13 enrolled pts completed 6 cycles of the study regimen prior to study closure. Of the 12 evaluable pts, the ORR was 100% with 9 pts (75%) achieving CR and 3 PR (25%). No pt experienced disease progression prior to study closing. Median time from treatment start to response was 165 (range 48-189) days. The most common adverse events were diarrhea (38%), neutropenia and anemia (31% each), fatigue, constipation, leukopenia and thrombocytopenia (23% each). Other AEs include colitis, nausea, hypoalbuminemia and hypokalemia (15% each). Of the 2 pts who developed colitis, 1 pt had G1 colitis which resolved, while the other pt discontinued the study after 2 cycles due to G3 colitis and bowel obstruction. Another pt experienced G3 jejunal perforation after completing cycle 6. Other G≥3 AE observed were neutropenia and leukopenia each (23% each), lung infection and lymphopenia (8% each). All pts were alive at the time of study closure. Conclusion: In this phase 1/II study, encouraging efficacy was observed with zandelisib + R-CHOP, but this should be interpreted with caution as the study was incomplete. There is a potential signal for increased gastrointestinal toxicity (one G3 colitis, one G3 bowel perforation) in this small sample size and larger prospective trials are needed to further assess the toxicity profile of the combination of oral PI3K inhibitors with R-CHOP.

Alpelisib: A Novel Agent for PIK3CA-Related Overgrowth Spectrum.

The aim of this review is to present the information a clinician will need when considering alpelisib therapy for a patient diagnosed with PIK3CA-related overgrowth spectrum (PROS). PROS is a condition caused by a somatic recessive gain-of-function mutation in the gene encoding phosphatidylinositol-3-kinase (PI3K). PROS is rare, affecting approximately 14 births per 1 million. PROS affects many different tissues including skin, bone, vascular, adipose, and connective tissues, thus its presentations vary widely. The presentation of PROS is often described as mosaic, as the disease typically does not affect all cells in the body. For patients two years of age and older requiring systemic therapy, alpelisib is an option which was recently granted accelerated approval by the US Food and Drug Administration (FDA) on April 5, 2022. Alpelisib is an inhibitor of PI3K, slowing the progression of existing lesions and preventing new lesions in patients with PROS. Important drug interactions exist with both CYP3A4 inducers and CYP2C9 substrates. Additionally, providers of patients receiving alpelisib should be aware of potential side effects including hypersensitivity, severe cutaneous adverse reactions, hyperglycemia, pneumonitis, diarrhea, and embryo-fetal toxicity. Despite the potential for adverse events, alpelisib has provided clinical benefit to many patients with PROS as evidenced by the current literature. This review collects and summarizes the currently available evidence, including a recently published case series and multiple case reports. Alpelisib is a promising new option for patients with PROS.

Response-adapted, time-limited venetoclax, umbralisib, and ublituximab for relapsed/refractory chronic lymphocytic leukemia

AbstractMany patients with chronic lymphocytic leukemia (CLL) will develop treatment resistance to Bruton tyrosine kinase (BTK) inhibitors. Phosphatidylinositol-3-kinase (PI3K) inhibitors, including umbralisib, have significant clinical activity in relapsed/refractory CLL, but prolonged exposure is associated with potential toxicities. Owing to the synergistic antitumor effects of combined PI3K and BCL-2 inhibition, we sought to explore the feasibility of response-adapted, time-limited therapy to optimize disease control while mitigating the risks of prolonged treatment. We conducted a phase 1/2 clinical trial to determine the safety and efficacy of venetoclax in combination with umbralisib and the anti-CD20 monoclonal antibody, ublituximab, (U2-VeN) in patients with relapsed/refractory CLL (N = 46) and Richter transformation (N = 5). After 12 cycles, treatment was stopped for patients with CLL who achieved undetectable minimal residual disease (uMRD). Adverse events of special interest included diarrhea in 50% of patients (11% grade 3/4), and aspartate aminotransferase and/or alanine aminotransferase elevation in 15 patients (33%), with 3 (7%) grade 3/4. There were no cases of tumor lysis syndrome related to venetoclax, with outpatient initiation in 96% of patients. The intent-to-treat overall response rate for CLL was 98% with best response of 100% in evaluable patients (42% complete responses). The end-of-treatment rate of uMRD at 10−4 in bone marrow was 77% (30/39), including a 71% uMRD rate among 14 patients refractory to prior BTK inhibitor. Time-limited venetoclax and U2 is safe and highly effective combination therapy for patients with relapsed/refractory CLL including those who have been previously treated with covalent BTK inhibitors. This trial was registered on www.clinicaltrials.gov as #NCT03379051.

Role of senkyunolide I in the promotion of neural stem/progenitor cell proliferation via the Akt/β-catenin pathway

Following brain injury, neural stem cells (NSCs) can generate mature neurons and replace damaged cells. However, the capacity of endogenous NSCs to self-repair from injured brain is limited as most NSCs die before becoming mature neurons. Therefore, a boosting endogenous NSCs by pharmacological support offers the potential to repair the damaged brain. Recently, small molecules have hold considerable promise for neuron regeneration and repair as they can penetrate the blood–brain barrier easily. Senkyunolide I (SEI) is a bioactive constituent derived from traditional Chinese medicines Ligusticum chuanxiong Hort. and Angelica sinensis (Oliv.) Diels, and was found to able to prevent ischemic stroke. This study examined the effects of SEI on the proliferation and neuronal lineage differentiation of prepared neural stem/progenitor cells (NS/PCs). The NS/PC proliferation was determined by 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt, and neurosphere formation assays. The NS/PC differentiation was also investigated by immunocytochemistry, and western blotting was employed to measure phosphorylated Akt (pAkt) and GSK-3β (pGSK-3β), and active-β-catenin protein levels. We showed that the NS/PC proliferation was enhanced after SEI exposure. Elevated cell numbers were also observed in neurospheres, which were incubated with SEI for 3 days, whereas the NS/PC differentiation was decreased after SEI exposure for 5 days. Furthermore, SEI upregulated pAkt/Akt and active-β-catenin levels and increased NS/PC proliferation after SEI treatment was reversed by phosphatidylinositol 3-kinase inhibitor LY294002. downregulated differentiated processes. Thus, SEI promoted the NS/PC proliferation and suppressed NS/PC differentiation into neurons and/or astrocytes, therefore SEI could be an interesting and promising candidate for stimulating NSCs.

Combined PI3K Inhibitor and Eribulin Enhances Anti-Tumor Activity in Preclinical Models of Paclitaxel-Resistant, PIK3CA-Mutated Endometrial Cancer.

Endometrial cancer stands as the predominant gynecological malignancy in developed nations. For advanced or recurrent disease, paclitaxel-based chemotherapy is the standard front-line therapy. However, paclitaxel resistance eternally develops. Based on the high prevalence of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutation, reaching 50%, in endometrial cancer, we preclinically investigated the effectiveness of a combination of a phosphatidylinositol 3-kinase (PI3K) inhibitor with eribulin, a post-paclitaxel therapy for breast cancer, in treating paclitaxel-resistant, PIK3CA-mutated endometrial cancer. We generated paclitaxel-resistant cell lines from PIK3CA-mutated endometrial cancer cell lines by gradually increasing the concentration of paclitaxel in cell cultures. We observed that the PI3K/AKT and epithelial-mesenchymal transition (EMT) pathways in paclitaxel-resistant cells were significantly upregulated compared with those in parental cells. Then, we demonstrated that the combination of alpelisib (a PI3K inhibitor) and eribulin more effectively suppressed the cellular growth of paclitaxel-resistant cells in in vitro and in vivo xenograft models. Mechanistically, we demonstrated that the effect of the combination could be enhanced by inhibiting both the PI3K/AKT and EMT pathways. Therefore, we suggest that paclitaxel resistance is associated with the activation of the PIK3/AKT pathway in PIK3CA-mutated endometrial cancer, and the combination of a PI3K inhibitor and eribulin merits further clinical investigation.

THU380 A Case Of Alpelisib Induced Diabetic Ketoacidosis (Dka) In A Patient With Type 2 Diabetes Mellitus And Rechallenge With SGLT2 Inhibitor

Abstract Disclosure: V. Sekar: None. S. Shaik: None. Introduction: Alpelisib is a α-selective phosphatidylinositol 3-kinase (PI3K) inhibitor recently used in treatment of advanced breast cancer. Hyperglycemia is an expected adverse effect with the use of PI3K inhibitors. We report a case of Alpelisib induced worsening hyperglycemia in a patient with type 2 diabetes mellitus who developed DKA while on Empagliflozin and was rechallenged with Dapagliflozin to achieve better glycemic control. Case Description: 60-year-old female with known history of type 2 diabetes mellitus was referred to Endocrinology prior to the start of PI3K inhibitor, Alpelisib for metastatic breast cancer. On initial visit her Hemoglobin A1C was 7.4 % and she was on Empagliflozin 25 mg daily, Sitagliptin 100 mg daily, Metformin XR 500 mg daily and Insulin Glargine 30 units daily. Three weeks after initiation of Alpelisib, patient reported uncontrolled fasting and post-prandial hyperglycemia, therefore her basal insulin was up-titrated and added on prandial insulin. Sitagliptin was discontinued. Two weeks later patient was admitted with Euglycemic diabetic ketoacidosis (DKA) which was treated with IV insulin and IV fluids. Empagliflozin was stopped and discharged on basal bolus regimen. In the next 6 weeks basal bolus regimen was significantly up-titrated and added on correctional insulin along with increasing Metformin XR to 500 mg twice a day due to poor glycemic control. During this time patient was cautiously restarted on Dapagliflozin 5 mg daily after discussing the better outcomes for Alpelisib induced hyperglycemia versus risk of DKA with reuse of SGLT2 inhibitors. Since being on Dapagliflozin her blood sugars were better controlled and the insulin requirements plateaued. Patient was closely monitored, and she didn’t develop further episode of DKA. Discussion: The PI3K pathway controls the effect of insulin intracellularly and its activation promotes tumor development, spread and failure to anticancer treatment. PI3K inhibitor blocks the intracellular action of insulin which causes reversible insulin resistance and hyperglycemia which is the major side effect of this drug. Use of insulin to treat hyperglycemia was shown to partially reactivate the PI3K pathway in tumoral cells, leading to cellular proliferation. Therefore, insulin should be kept as the last line antihyperglycemic agent. Exploratory analysis of SOLAR-1* trial has shown better glycemic control with use of SGLT2 inhibitors in patient with Alpelisib induced hyperglycemia along with improved efficacy of Alpelisib against tumor growth. Both PI3K inhibitor and SGLT2 inhibitor has risk of causing DKA, but close monitoring and patient education helps to reduce the risk. Reference *Study Assessing the Efficacy and Safety of Alpelisib Plus Fulvestrant in Men and Postmenopausal Women with Advanced Breast Cancer Which Progressed on or After Aromatase Inhibitor Treatment Presentation: Thursday, June 15, 2023

FRI610 Phosphatidylinositol 3-kinase Inhibition With Alpelisib Is Safe And Effective In Treating Refractory Hypoglycemia Associated With Malignant Insulinoma

Abstract Disclosure: Y. Kang: None. D.A. Rubinson: None. I. Odintsov: None. A. Vaidya: None. J.S. Williams: None. G.K. Adler: None. M.E. McDonnell: None. M. Patti: Advisory Board Member; Self; Fractyl Laboratories. Consulting Fee; Self; AstraZeneca, Hanmi Pharmaceuticals, MBX. Grant Recipient; Self; Dexcom. N.E. Palermo: None. Background: Nonfunctioning malignant pancreatic neuroendocrine tumors (PNETs) can transform to functional PNETs. Transformation into insulin-secreting PNET (ISPNET) is associated with poor overall survival and refractory hypoglycemia, often requiring ICU care. We present a case of refractory hypoglycemia due to ISPNET, which was successfully treated with alpelisib, an inhibitor of phosphatidylinositol 3-kinase (PI3K) currently approved for breast cancer. Clinical Case: A 79-year-old man with a 5-year history of type 2 diabetes and 10-year history of grade II, well-differentiated, non-functioning PNET (Ki67 15%) with hepatic metastasis presented with worsening symptomatic hypoglycemia. He discontinued his antidiabetic agent 3 months ago due to hypoglycemia and was on lanreotide and everolimus as PNET treatment. Evaluation revealed plasma glucose 29 mg/dL, proinsulin >700 pmol/L (reference: 3.6-22), insulin 116 uIU/mL (2.6-24.9), C-peptide 12.0 ng/mL (1.1-4.4), beta-hydroxybutyrate 0.1 mmol/L (<0.3), and negative sulfonylurea panel. Imaging showed extensive progression of hepatic metastases, and debulking hepatectomy was performed. Pathology showed grade III PNET with positive insulin staining and mib-1 index of 22%. After 2 months of euglycemia post-surgery, he was readmitted to the ICU with refractory hypoglycemia. Evaluation showed plasma glucose 91 mg/dL, proinsulin, and insulin levels above-assay (>700 pmol/L and >930.0 uIU/mL, respectively) and C-peptide 71.8 ng/mL; imaging revealed hepatic tumor progression. Severe hypoglycemia as low as 34 mg/dL was noted despite therapy with IV dextrose (30%, up to 100 cc/hr), glucagon infusion (0.6 mg/hr), dexamethasone 20 mg QD, and diazoxide 30 mg TID. Debilitating anasarca developed despite aggressive diuresis, attributed to high-volume IV dextrose, diazoxide, and renal dysfunction. Two hours after 300 mg alpelisib administration, patient exhibited hyperglycemia, allowing discontinuation of dextrose infusion 8 hours later. Glucagon infusion was subsequently discontinued, and he was discharged to home. Within 20 days, the patient was able to discontinue all diuretics, dexamethasone, and cornstarch. Patient had no side effects related to alpelisib and performance status returned to baseline. Glucose ranged between 160-300 mg/dL without any hypoglycemia. On week 4 of alpelisib, plasma glucose was 340 mg/dL, proinsulin >700 pmol/L, insulin 181 uIU/mL, and C-peptide 20.2 ng/mL. Conclusion: To our knowledge, this is the first case demonstrating alpelisib as a safe and effective option in refractory hypoglycemia associated with insulinoma. While it is unclear whether this is mediated by anti-tumor effects or solely by blockade of insulin action, PI3-K inhibition should be considered as a treatment option in patients with ISPNET in whom hypoglycemia has failed to improve with conventional approaches. Presentation: Friday, June 16, 2023

THU259 Alpelisib-induced Diabetic Ketoacidosis: Call For A Multidisciplinary Approach

Abstract Disclosure: N. Kalara: None. P. Rios: None. F. Vendrame: None. Introduction: Alpelisib is a p110a subunit phosphatidylinositol-3kinase inhibitor (PI3K) approved for treating hormone receptor-positive, human epidermal growth factor receptor 2-negative, PIK3CA mutated, advanced or metastatic breast cancer. PI3K signaling is essential for the metabolic action of insulin and the inhibition of p110a subunit is associated with hyperinsulinemia and hyperglycemia. In the combination (Alpelisib-Fulvestrant) arm of phase III SOLAR-1 study the all-grade incidence of hyperglycemia was 63%, but diabetic ketoacidosis (DKA) was also observed and reported in 0.7% of patients. To the best of our knowledge, less than 10 cases of Alpelisib-induced DKA have been reported in the literature. Here we describe an additional case. Case Description: A 62-year-old female with a history of metastatic breast cancer, hypertension, and prediabetes, presented with 3 days of nausea, vomiting, abdominal pain, weakness, polyuria, and polydipsia. Fifteen days prior to the presentation the HbA1c was 6.1% for which she was started on metformin 500 mg daily. Alpelisib 150 mg PO BID and Fluvestrant (Estrogen receptor antagonist) were also started the same day. The patient was told to stop the PIK3 inhibitor if the blood glucose increased above 200 mg/dL. The review of system was positive for fatigue, decreased appetite, malaise, 5 lbs weight loss during the previous week, and headache. She had no family history of any endocrinologic disease. The physical exam was unremarkable with no signs of insulin resistance. Laboratory tests revealed pH 7.31 (7.35-7.45), HCO3 10 mmol/L (22-26), PCO2 21 mmHg (35-45), glucose 884 mg/dL (74-106), sodium 120 mmol/L (136-145), K 5.2 mmol/L (3.5-5.1), Cl 93 mmol/L (98-107), CO2 7 mmol/L (21-32), anion gap 22 mmol/L (5-15), GFR 30 mL/min/1.73m2 (>60), Cr 1.80 mg/dL (0.5-1.02), BUN 43 mg/dL (7-18), beta-hydroxybutyrate 3 mmol/L (0.4-0.5), HbA1c 9.2% (4.2-5.6). Additional testing revealed C-peptide 2.3 ng/ml (1.1-4.4) with glucose 397 mg/dL. Results suggested a combined DKA and hyperosmolar hyperglycemic state (HHS). Alpelisib was discontinued and the patient was managed with insulin drip, fluids, electrolyte replacement, and eventually transitioned to a basal-bolus regimen (0.5U/kg). The patient was discharged on metformin and Insulin glargine with the recommendation to follow up with endocrinology and oncology. Conclusion: Our case highlights the importance of blood glucose and HbA1c screening before starting Alpelisib with emphasis on a multidisciplinary approach to monitor blood glucose levels to prevent DKA. Reference: 1. Farah SJ, Masri N, Ghanem H, Azar M. Diabetic ketoacidosis associated with alpelisib treatment of metastatic breast cancer. AACE Clin Case Rep. 2020;6(6):e349-e351. doi: 10.4158/ACCR-2020-0452 Presentation: Thursday, June 15, 2023