Dual Inhibitor Research Articles

Two novel angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibiting peptides from tilapia (Oreochromis mossambicus) skin and their molecular docking mechanism.

In the study, papain was used to hydrolyze tilapia (Oreochromis mossambicus) skin to obtain a tilapia skin hydrolysate (TSH) with dual angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. The resulting TSH was sequentially fractionated by ultrafiltration, size exclusion separation chromatography, and reverse-phase high-performance liquid chromatography. Its inhibitory effects on ACE and DPP-IV were determined by commercial reagent kits. Two peptides purified from TSH were identified as Gly-Pro-Leu-Gly-Ala-Leu (GPLGAL) and Lys-Pro-Ala-Gly-Asn (KPAGN) by the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Inhibitory concentration (IC50) of GPLGAL on ACE and DPP-IV were 117.20±1.69 and 187.10±2.75µM, respectively. IC50 of KPAGN on ACE and DPP-IV were 137.40±2.33 and 259.20±2.85µM, respectively. The molecular simulation demonstrated that the binding affinities of GPLGAL to ACE and DPP-IV proteins were -8.5 and -7.4kcal/mol, respectively, whereas those of KPAGN to ACE and DPP-IV proteins were -7.9 and -6.7kcal/mol, respectively. GPLGAL interacted with 21 amino acid residues of the ACE active site, whereas KPAGN engaged with 19 amino acid residues. Additionally, GPLGAL interacted with 10 amino acid residues of the DPP-IV active site, whereas KPAGN engaged with 13 amino acid residues. The two peptides predominantly occupied the active sites of ACE (His513, Tyr523, and Ala354) and DPP-IV (Tyr662 and Arg125) through hydrogen bonding. This leads to the deactivation of ACE and DPP-IV. PRACTICAL APPLICATION: Accelerate tilapia skin development and high-value utilization; provide foundation for preparing the peptides with dual ACE and DPP-IV inhibiting activity.

Design, synthesis, and biological evaluation of 3-phenyl substituted pyridine derivatives as potential dual inhibitors of XOR and URAT1

Xanthine oxidoreductase (XOR) and uric acid transporter 1 (URAT1) are two most widely studied targets involved in production and reabsorption of uric acid, respectively. Marketed drugs almost target XOR or URAT1, but sometimes, single agents might not achieve aim of lowering uric acid to ideal value in clinic. Thus, therapeutic strategies of combining XOR inhibitors with uricosuric drugs were proposed and implemented. Based on our initial work of virtual screening, A and B were potential hits for dual-targeted inhibitors on XOR/URAT1. By docking A/B with XOR/URAT1 respectively, compounds I1-7 were designed to get different degree of inhibition effect on XOR and URAT1, and I7 showed the best inhibitory effect on XOR (IC50 = 0.037 ± 0.001 μM) and URAT1 (IC50 = 546.70 ± 32.60 μM). Further docking research on I7 with XOR/URAT1 led to the design of compounds II with the significantly improved inhibitory activity on XOR and URAT1, such as II11 and II15. Especially, for II15, the IC50 of XOR is 0.006 ± 0.000 μM, superior to that of febuxostat (IC50 = 0.008 ± 0.000 μM), IC50 of URAT1 is 12.90 ± 2.30 μM, superior to that of benzbromarone (IC50 = 27.04 ± 2.55 μM). In acute hyperuricemia mouse model, II15 showed significant uric acid lowering effect. The results suggest that II15 had good inhibitory effect on XOR/URAT1, with the possibility for further investigation in in-vivo models of hyperuricemia.

Design, synthesis, and biological evaluation of novel benzimidazole derivatives as anti-cervical cancer agents through PI3K/Akt/mTOR pathway and tubulin inhibition

Phosphatidylinositol 3-kinase (PI3K) is one of the most attractive therapeutic targets for cervical cancer treatment. In this study, we designed and synthesized a series of benzimidazole derivatives and evaluated their anti-cervical cancer activity. Compound 4r exhibited strong antiproliferative activity in different cervical cancer cell lines HeLa, SiHa and Ca Ski, and relative lower cytotoxicity to normal hepatic and renal cell lines LO2 and HEK-293t (IC50 values were at 21.08 μM and 23.96 μM respectively). Its IC50 value was at 3.38 μM to the SiHa cells. Further mechanistic studies revealed that 4r induced apoptosis, arrested cell cycle in G2/M phase, suppressed PI3K/Akt/mTOR pathway and inhibit the polymerization of tubulin. Molecular docking study suggested that 4r formed key H-bonds action with PI3Kα (PDB ID:8EXU) and tubulin (PDB ID:1SA0). Zebrafish acute toxicity experiments showed that high concentrations of 4r did not cause death or malformation of zebrafish embryos. All these results demonstrated that 4r would be a promising lead candidate for further development of novel PI3K and tubulin dual inhibitors in cervical cancer treatment.

Pan-inhibition of the three H2S synthesizing enzymes restrains tumor progression and immunosuppression in breast cancer

BackgroundHydrogen sulfide (H2S) is a significant endogenous mediator that has been implicated in the progression of various forms of cancer including breast cancer (BC). Cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST) are the three principal mammalian enzymes responsible for H2S production. Overexpression of CBS, CSE and 3MST was found to be associated with poor prognosis of BC patients. Moreover, H2S was linked to an immune-suppressive tumor microenvironment in BC. Recently it was observed that BC cells, in response to single or dual inhibition of H2S synthesizing enzymes, develop an escape mechanism by overexpressing alternative sources of H2S generation. Thus, the aim of this work is to escape the H2S compensatory mechanism by pan repressing the three enzymes using microRNAs (miRNAs) and to investigate their impact on the oncogenic and immunogenic profile of BC cells.MethodsBC female patients (n = 25) were recruited. In-silico analysis was used to identify miRNAs targeting CBS, CSE, and 3MST. MDA-MB-231 cells were cultured and transfected using oligonucleotides. Total RNA was extracted using Biazol, reverse transcribed and quantified using qRT-PCR. H2S levels were measured using AzMc assay. BC hallmarks were assessed using trans-well migration, wound healing, MTT, and colony forming assays.ResultsmiR-193a and miR-548c were validated by eight different bioinformatics software to simultaneously target CBS, CSE and 3MST. MiR-193a and miR-548c were significantly downregulated in BC tissues compared to their non-cancerous counterparts. Ectopic expression of miR-193a and miR-548c in MDA-MB-231 TNBC cells resulted in a marked repression of CBS, CSE, and 3MST transcript and protein levels, a significant decrease in H2S levels, reduction in cellular viability, inhibition of migration and colony forming ability, repression of immune-suppressor proteins GAL3 GAL9, and CD155 and upregulation of the immunostimulatory MICA and MICB proteins.ConclusionThis study sheds the light onto miR-193a and miR-548c as potential pan-repressors of the H2S synthesizing enzymes. and identifies them as novel tumor suppressor and immunomodulatory miRNAs in TNBC.

Inhibition of the mPTP and Lipid Peroxidation Is Additively Protective Against I/R Injury.

During myocardial ischemia/reperfusion (I/R) injury, high levels of matrix Ca2+ and reactive oxygen species (ROS) induce the opening of the mitochondrial permeability transition pore (mPTP), which causes mitochondrial dysfunction and ultimately necrotic death. However, the mechanisms of how these triggers individually or cooperatively open the pore have yet to be determined. Here, we use a combination of isolated mitochondrial assays and in vivo I/R surgery in mice. We challenged isolated liver and heart mitochondria with Ca2+, ROS, and Fe2+ to induce mitochondrial swelling. Using inhibitors of the mPTP (cyclosporine A or ADP) lipid peroxidation (Fer-1 [ferrostatin-1], mitoquinone), we determined how the triggers elicit mitochondrial damage. Additionally, we used the combination of inhibitors during I/R injury in mice to determine if dual inhibition of these pathways is additivity protective. In the absence of Ca2+, we determined that ROS fails to trigger mPTP opening. Instead, high levels of ROS induce mitochondrial dysfunction and rupture independently of the mPTP through lipid peroxidation. As expected, Ca2+ in the absence of ROS induces mPTP-dependent mitochondrial swelling. Subtoxic levels of ROS and Ca2+ synergize to induce mPTP opening. Furthermore, this synergistic form of Ca2+- and ROS-induced mPTP opening persists in the absence of CypD (cyclophilin D), suggesting the existence of a CypD-independent mechanism for ROS sensitization of the mPTP. These ex vivo findings suggest that mitochondrial dysfunction may be achieved by multiple means during I/R injury. We determined that dual inhibition of the mPTP and lipid peroxidation is significantly more protective against I/R injury than individually targeting either pathway alone. In the present study, we have investigated the relationship between Ca2+ and ROS, and how they individually or synergistically induce mitochondrial swelling. Our findings suggest that Ca2+ mediates mitochondrial damage through the opening of the mPTP, although ROS mediates its damaging effects through lipid peroxidation. However, subtoxic levels both Ca2+ and ROS can induce mPTP-mediated mitochondrial damage. Targeting both of these triggers to preserve mitochondria viability unveils a highly effective therapeutic approach for mitigating I/R injury.

A Novel Class of Human ADAM8 Inhibitory Antibodies for Treatment of Triple-Negative Breast Cancer.

New targeted treatments are urgently needed to improve triple-negative breast cancer (TNBC) patient survival. Previously, we identified the cell surface protein A Disintegrin And Metalloprotease 8 (ADAM8) as a driver of TNBC tumor growth and spread via its metalloproteinase and disintegrin (MP and DI) domains. In proof-of-concept studies, we demonstrated that a monoclonal antibody (mAb) that simultaneously inhibits both domains represents a promising therapeutic approach. Here, we screened a hybridoma library using a multistep selection strategy, including flow cytometry for Ab binding to native conformation protein and in vitro cell-based functional assays to isolate a novel panel of highly specific human ADAM8 dual MP and DI inhibitory mAbs, called ADPs. The screening of four top candidates for in vivo anti-cancer activity in an orthotopic MDA-MB-231 TNBC model of ADAM8-driven primary growth identified two lead mAbs, ADP2 and ADP13. Flow cytometry, hydrogen/deuterium exchange-mass spectrometry (HDX-MS) and alanine (ALA) scanning mutagenesis revealed that dual MP and DI inhibition was mediated via binding to the DI. Further testing in mice showed ADP2 and ADP13 reduce aggressive TNBC characteristics, including locoregional regrowth and metastasis, and improve survival, demonstrating strong therapeutic potential. The continued development of these mAbs into an ADAM8-targeted therapy could revolutionize TNBC treatment.

Pyrano[2,3-c]pyrazole fused spirooxindole-linked 1,2,3-triazoles as antioxidant agents: Exploring their utility in the development of antidiabetic drugs via inhibition of α-amylase and DPP4 activity

Environment-benign, multicomponent synthetic methodologies are vital in modern pharmaceutical research and facilitates multi-targeted drug development via synergistic approach. Herein, we reported green and efficient synthesis of pyrano[2,3-c]pyrazole fused spirooxindole linked 1,2,3-triazoles using a tea waste supported copper catalyst (TWCu). The synthetic approach involves a one-pot, five-component reaction using N-propargylated isatin, hydrazine hydrate, ethyl acetoacetate, malononitrile/ethyl cyanoacetate and aryl azides as model substrates. Mechanistically, the reaction was found to proceed via in situ pyrazolone formation followed by Knoevenagel condensation, azide alkyne cycloaddition and Michael's addition reactions. The molecules were developed using structure-based drug design. The primary goal is to identifying anti-oxidant molecules with potential ability to modulate α-amylase and DPP4 (dipeptidyl-peptidase 4) activity. The anti-oxidant analysis, as determined via DPPH, suggested that the synthesized compounds, A6 and A10 possessed excellent anti-oxidant potential compared to butylated hydroxytoluene (BHT). In contrast, compounds A3, A5, A8, A9, A13, A15, and A18 were found to possess comparable anti-oxidant potential. Among these, A3 and A13 possessed potential α-amylase inhibitory activity compared to the acarbose, and A3 further emerged as dual inhibitors of both DPP4 and α-amylase with anti-oxidant potential. The relationship of functionalities on their anti-oxidant and enzymatic inhibition was explored in context to their SAR that was further corroborated using in silico techniques and enzyme kinetics.

Dual Inhibition of Factor XIIa and Factor XIa Produces a Synergistic Anticoagulant Effect

Dual Inhibition of Factor XIIa and Factor XIa Produces a Synergistic Anticoagulant Effect

New phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamides as dual inhibitors against α-glucosidase and PTP-1B for the treatment of type 2 diabetes.

This study describes the design, synthesis, and evaluation of a novel series of phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamide derivatives (7a-l) as dual inhibitors of α-glucosidase and protein tyrosine phosphatase 1-B (PTB-1B). The latter enzymes are two important targets in the treatment of type 2 diabetes. The in vitro obtained data demonstrated that all title compounds 7a-l were more potent than the standard inhibitor acarbose against α-glucosidase while only four derivatives (7a, 7g, 7h, and 7h) were more potent than the standard inhibitor suramin against PTP-1B. Furthermore, these data showed that the most potent α-glucosidase inhibitor was compound 7i, with sixfold higher inhibitory activity than acarbose, and the most potent PTP-1B inhibitor was compound 7a with 3.5-fold higher inhibitory activity than suramin. Kinetic studies of compounds 7i and 7a revealed that they inhibited their target enzymes in a competitive mode. The docking study demonstrated that compounds 7i and 7a well occupied the active site pockets of α-glucosidase and PTP-1B, respectively. In silico pharmacokinetic and toxicity assays of the most potent compounds were performed, and the obtained results were compared with those of the standard inhibitors.

Combination of dasatinib and venetoclax in newly diagnosed chronic phase chronic myeloid leukemia.

The dual inhibition of the BCR::ABL1 tyrosine kinase and BCL-2 could potentially deepen the response rates of chronic myeloid leukemia in chronic phase (CML-CP). This study evaluated the safety and efficacy of the combination of dasatinib and venetoclax. In this phase 2 trial, patients with CML-CP or accelerated phase (clonal evolution) received dasatinib 50 mg/day for three courses; venetoclax was added in course 4 for 3 years. The initial venetoclax dose was 200 mg/day continuously but reduced later to 200 mg/day for 14 days, and to 100 mg/day for 7 days per course once a molecular response (MR)4.5 was achieved. After 3 years of combination, patients were maintained on single-agent dasatinib. The primary end point was the rate of major molecular response (MMR) by 12 months of combination. Sixty-five patients were treated. Their median age was 46 years (range, 23-73). By 12 months of combination, the MMR, MR4, and MR4.5 rates were 86%, 53%, and 45%, respectively. After a median follow-up of 42 months, the 4-year event-free and overall survival rates were 96% and 100%, respectively. Outcomes with the combination were comparable to historical outcomes with single-agent dasatinib (cumulative 12-months MMR rate of 79% with both strategies). The incidence of grade 3-4 neutropenia was 22% with the combination and 11% with single-agent dasatinib (p<.001). Treatment with dasatinib and venetoclax was safe and effective in CML-CP. The cumulative response rates with the combination were similar to those with single-agent dasatinib. Further follow-up is needed to evaluate the rates of durable deep molecular response and treatment-free remission.

A novel dual ATM/DNA-PK inhibitor, XRD-0394, potently radiosensitizes and potentiates PARP and topoisomerase I inhibitors.

A majority of cancer patients receive radiation therapy as part of their treatment regimens whether using external beam therapy or locally-delivered radioisotopes. While often effective, some tumors are inadequately controlled with radiation and radiation therapy has significant short-term and long-term toxicities for cancer survivors. Insights into molecular mechanisms involved in cellular responses to DNA breaks introduced by radiation or other cancer therapies have been gained in recent years and approaches to manipulate these responses to enhance tumor cell killing or reduce normal tissue toxicity are of great interest. Here, we report the identification and initial characterization of XRD-0394, a potent and specific dual inhibitor of two DNA damage-response kinases, ATM and DNA-PKcs. This orally bioavailable molecule demonstrates significantly enhanced tumor cell kill in the setting of therapeutic ionizing irradiation in vitro and in vivo. XRD-0394 also potentiates the effectiveness of topoisomerase I inhibitors in vitro. Additionally, in cells lacking BRCA1/2 XRD-0394 shows single agent activity and synergy in combination with PARP inhibitors. A Phase Ia clinical trial (NCT05002140) with XRD-0394 in combination with RT has completed. These results provide a rationale for future clinical trials with XRD-0394 in combination with RT, PARP inhibitors and targeted delivery of topoisomerase I inhibitors.

Co-operation of MCL-1 and BCL-XL anti-apoptotic proteins in stromal protection of MM cells from carfilzomib mediated cytotoxicity.

BCL-2 family proteins are important for tumour cell survival and drug resistance in multiple myeloma (MM). Although proteasome inhibitors are effective anti-myeloma drugs, some patients are resistant and almost all eventually relapse. We examined the function of BCL-2 family proteins in stromal-mediated resistance to carfilzomib-induced cytotoxicity in MM cells. Co-cultures employing HS5 stromal cells were used to model the interaction with stroma. MM cells were exposed to CFZ in a 1-hour pulse method. The expression of BCL-2 family proteins was assessed by flow cytometry and WB. Pro-survival proteins: MCL-1, BCL-2 and BCL-XL were inhibited using S63845, ABT-199 and A-1331852 respectively. Changes in BIM binding partners were examined by immunoprecipitation and WB. CFZ induced dose-dependent cell death of MM cells, primarily mediated by apoptosis. Culture of MM cells on HS-5 stromal cells resulted in reduced cytotoxicity to CFZ in a cell contact-dependent manner, upregulated expression of MCL-1 and increased dependency on BCL-XL. Inhibiting BCL-XL or MCL-1 with BH-3 mimetics abrogated stromal-mediated protection only at high doses, which may not be achievable in vivo. However, combining BH-3 mimetics at sub-therapeutic doses, which alone were without effect, significantly enhanced CFZ-mediated cytotoxicity even in the presence of stroma. Furthermore, MCL-1 inhibition led to enhanced binding between BCL-XL and BIM, while blocking BCL-XL increased MCL-1/BIM complex formation, indicating the cooperative role of these proteins. Stromal interactions alter the dependence on BCL-2 family members, providing a rationale for dual inhibition to abrogate the protective effect of stroma and restore sensitivity to CFZ.

Abstract CT062: A phase 1 study of tamnorzatinib (ONO-7475), an Axl/Mer dual inhibitor, alone and in combination with nivolumab in patients with advanced or metastatic solid tumors

Abstract Background: Tamnorzatinib (ONO-7475) is an orally active small molecule Axl/Mer dual inhibitor that not only directly acts on cancer cells to suppress their proliferation, but also on immune cells and exerts characteristics of cancer immunotherapy. Methods: We performed a phase 1 study to assess the tolerability, safety, and pharmacokinetics of ONO-7475 alone (Part A) and in combination with nivolumab (NIVO) (Part B) in Japanese patients (pts) with advanced or metastatic solid tumors (NCT03730337). Patients received once-daily ONO-7475 (3-10 mg, orally) as a monotherapy or in combination with NIVO (240 mg, i.v., every 2 weeks). Results: Twelve pts in both Part A and Part B (three each at 3 and 6 mg, and six at 10 mg ONO-7475) received the study treatment. Baseline characteristics, safety, and efficacy outcomes are summarized in the Table. While one of six pts in the Part B 10-mg cohort developed dose-limiting toxicities of grade 4 nephritis, grade 3 colitis, and grade 3 hepatic function abnormal, no others did. In biomarker analyses, activation of T cell function and an increase in T cell number, an increase in inflammatory (M1) macrophages/immunosuppressive (M2) macrophages ratio, and suppression of epithelial-to-mesenchymal transition were observed after treatment. Conclusion: ONO-7475 was tolerated at repeated once-daily oral doses up to 10 mg as a monotherapy and in combination with NIVO in pts with advanced or metastatic solid tumors. TABLE 1. NAND Table. Baseline Characteristics, Safety Outcomes, and Efficacy Outcomes Part A (ONO-7475 alone) N = 12 Part B (ONO-7475 + NIVO) N = 12 Baseline Characteristics Median age, years (range) 63.5 (31–76) 56.0 (39–72) Female, n (%) 8 (66.7) 9 (75.0) ECOG PS, n (%) 0 8 (66.7) 10 (83.3) 1 4 (33.3) 2 (16.7) Safety Outcomes Number of patients with AEs (%) Any grade 11 (91.7) 11 (91.7) Glade ≥3 0 2 (16.7) *2 Number of patients with SAEs (%) 2 (16.7) *1 1 (8.3) *3 *1 Pyrexia and diverticulitis (1 patient each) *2 Grade 4 neutrophil count decreased (1 patient), grade 4 lymphocyte count decreased and nephritis (1 patient each), and grade 3 colitis, enterocolitis infectious, device related infection, anemia, hyperglycemia, and hepatic function abnormal (1 patient) *3 Colitis, hepatic function abnormal, and nephritis Efficacy Outcomes Objective Response Rate, n (%) [95% CI] 0 [0.0, 26.5] 1 (8.3) [0.2, 38.5] Disease Control Rate, n (%) [95% CI] 3 (25.0) [5.5, 57.2] 4 (33.3) [9.9, 65.1] Best Overall Response, n (%) [95% CI] Complete Response 0 [0.0, 26.5] 0 [0.0, 26.5] Partial Response 0 [0.0, 26.5] 1 (8.3) [0.2, 38.5] Stable Disease 3 (25.0) [5.5, 57.2] 3 (25.0) [5.5, 57.2] Progressive Disease 9 (75.0) 5 (41.7) Not Evaluable 0 3 (25.0) Median OS, months [95% CI] 12.21 [4.93, not reached] 16.99 [5.98, not reached] Median PFS, months [95% CI] 1.86 [0.92, 3.84] 2.17 [0.95, 3.78] Citation Format: Yuki Katsuya, Kan Yonemori, Toshio Shimizu, Takafumi Koyama, Sigehisa Kitano, Kazuki Sudo, Shunsuke Kondo, Jun Sato, Hiroaki Hozumi, Noboru Yamamoto. A phase 1 study of tamnorzatinib (ONO-7475), an Axl/Mer dual inhibitor, alone and in combination with nivolumab in patients with advanced or metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT062.

Abstract LB273: Pharmacological synthetic lethality by co-inhibition of PARP and HDAC enzymes

Abstract Introduction: Inhibition of poly(ADP-ribose) polymerase (PARP) induces synthetic lethality in cells exhibiting defects in homologous repair (HR) pathways, such as BRCA1 and BRCA2-mutated breast or ovarian cancers, and 4 different PARP inhibitors (PARPi) are currently approved by the FDA. While HR-deficient cancers usually respond well to single agent PARPi, HR-proficient cancers are generally less sensitive to the treatment. Acquired resistance to PARPi due to activating mutations in BRCA genes are also not uncommon. In this work, we have examined strategies for enhancing PARPi activity in a HR-proficient context and identified histone deacetylases (HDACs) as targets for pharmacological synthetic lethality in the context of PARPi. Materials and methods: PARP1 and PARP2 activity were measured using Trevigen Universal Colorimetric PARP Assay Kit, BPS Bioscience PARP2 Colorimetric PARP2 Assay Kit, and PARylation assay. HDAC activity was measured using HeLa cell nuclear extracts and a fluorogenic peptide-based biochemical assay. Cell survival EC50 were determined using CellTiter Glo viability assay. Cell cycle analysis was performed by flow cytometry with propidium iodide staining. DNA damage was investigated by immunoblotting and immunofluorescence using gamma-H2AX antibodies, and comet assays for confirmation of double-strand breaks. Spheroid assays were performed using the Incucyte® S3 spheroid analysis module. In vivo metastasis formations were examined using the pulmonary metastasis assay (PuMA). Results and discussion: Combinations of PARP and HDAC inhibitors in HR-proficient tumor cells demonstrated that HDACi could enhance the efficacy of PARPi in vitro. This was associated with increased acute and sustained DNA-damage distinct cell cycle profiles showing activity in both S- and G2/M-phases. Importantly, dual single-molecule PARP-HDAC inhibitors showed potent inhibition of PARP1 and PARP2 activity and PAR synthesis, comparable to olaparib, as well as inhibition of HDAC with IC50 values in the low µM range. Dual PARP-HDAC inhibition decreased survival of HR-proficient cells in both 2D cultures and 3D spheroid assays with lower EC50 values than olaparib or vorinostat alone. Importantly, lung metastasis formation was significantly impaired by dual PARP-HDAC inhibition. Conclusion: Combination of PARP inhibition and HDAC inhibition showed increased efficacy compared to single agent PARP inhibition in HR-proficient cells. Development of bifunctional inhibitors may provide a novel therapeutic opportunity for tumors with limited response rates to single agent PARPi. Citation Format: Sarah Truong, Louise Ramos, Beibei Zhai, Fariba Ghaidi, Mona Marzban, Hans Adomat, Xiaoqi Chen, John Langlands, Dennis Brown, Jeffrey Bacha, Colin Collins, Poul H. Sorensen, Wang Shen, Mads Daugaard. Pharmacological synthetic lethality by co-inhibition of PARP and HDAC enzymes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB273.

Abstract LB176: Targeting the PI3K/Akt/mTOR pathway in non-small cell lung cancer spheroids

Abstract A major barrier in lung cancer pre-clinical research is the lack of simple, replicative and reproducible cell culture models. Most studies are still focused on 2D, completely ignoring cell-to-cell interactions, in vivo tissue architecture and the surrounding microenvironment. To address this void in cancer research, we aimed to develop a biomimetic 3D lung cancer spheroid model that can be used as a more reliable tool for pharmacological studies. Therefore, 3D spheroids of A549 (adenocarcinoma), H460 (large cell carcinoma) and H520 (squamous cell carcinoma) non-small cell lung cancer (NSCLC) cells were optimized and consequently submitted to AZD2014 treatment, a dual mTOR inhibitor targeting mTORC1 and mTORC2, members of the PI3K/Akt/mTOR pathway, which is commonly deregulated in lung cancer. Each cell line was seeded at 2000, 5000 or 10000 cells/spheroid in agarose micro-molds for eight days. The 3D NSCLC spheroids were further characterized for their tumor features, namely 3D dynamics and morphology, including diameter, circularity and compactness, viability properties, as well as proliferative and necrotic areas. Based on this characterization, the 2000 cells/spheroid condition was selected for further treatments and spheroid treatment time-points were selected. For each cell line, spheroids were treated with AZD2014, using concentrations based on the IC30 values (sensitization concentration) defined under 2D conditions: 10 μM, 10 μM and 0.2 μM for A549, H460 and H520 spheroids, respectively. Treated and untreated spheroids were followed during six days post-treatment, and their morphological characteristics, cell viability, necrotic core formation and proliferative areas, as well as ATP production, were assessed. Spheroids of all cell lines exhibited a significant inhibition of spheroid growth with AZD2014 treatment, which was maintained over the six days. Moreover, a reduction in spheroid intracellular ATP was observed at days three and six post-treatment. An additional treatment regimen was studied by re-treating spheroids with the same concentration of AZD2014 after 48hrs from the first treatment. Spheroids exposed to this dual treatment regimen exhibited a significant inhibition of spheroid growth, while the respective controls exhibited intensified growth. While AZD2014 did not induce significant reductions in 3D cell viability, a clear inhibition of spheroid growth was observed. Having a more intricate cellular organization, this study alleviates the increased complexity of pharmacological responses in 3D spheroids when compared to 2D models. Further studies are being carried out to define the enhanced biomimetic ability of these NSCLC spheroids and the underlying mechanisms involved when targeting the PI3K/Akt/mTOR pathway using AZD2014 as mono-therapy or in combination with two novel anti-sense oligonucleotides (ASO). Citation Format: Nathan Vella, Diogo Estêvão, Tânia Cruz, Maria José Oliveira, Anthony George Fenech, Vanessa Petroni Magri. Targeting the PI3K/Akt/mTOR pathway in non-small cell lung cancer spheroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB176.

Abstract CT087: A phase 1/2, open-label, randomized, dose-finding and dose expansion study of gedatolisib in combination with darolutamide in metastatic castration-resistant prostate cancer (mCRPC)

Abstract Background: Progression to metastatic castration-resistant prostate cancer (mCRPC) occurs in most patients treated with androgen receptor signaling inhibitors (ARSi) for advanced disease. Preclinical studies demonstrate that AR and PI3K - AKT - mTOR (PAM) pathways interact through reciprocal negative feedback, whereby inhibition of one pathway activates the other. Thus, combining a PAM inhibitor with an ARSi may deliver improved anti-cancer activity in patients with mCRPC. A Phase 2 trial in 129 patients with mCRPC who progressed on abiraterone demonstrated improved median radiographic progression-free survival (rPFS) when samotolisib, a dual PI3K-mTOR inhibitor, was added to enzalutamide. These results form the basis for this clinical trial of gedatolisib, a potent PAM inhibitor, in combination with darolutamide in men with mCRPC who have previously progressed on ARSi (NCT06190899). Methods: This open-label, multicenter, Phase 1/2 study will evaluate the safety and efficacy of gedatolisib in combination with darolutamide in men with mCRPC who have progressed on ARSi. In Phase 1, 36 patients will be randomized to one of two dose arms to evaluate dose limiting toxicities (DLTs) and determine the recommended Phase 2 dose (RP2D). Gedatolisib will be administered once weekly for 3-weeks-on/1-week-off: Arm 1 - 120 mg and Arm 2 - 180 mg, with darolutamide 600 mg orally administered twice daily. Arm 2 may be dose de-escalated depending on the number of DLTs observed. In Phase 2, 12 additional patients will be enrolled at the RP2D (n= 30). Key inclusion criteria include adult males (≥ 18 years) with mCRPC who have progressed on or after treatment with one next-generation ARSi. Key exclusion criteria include males with adenocarcinoma with a small cell component and with ≥10% neuroendocrine type cells; prior treatment with PI3K, AKT, or mTOR inhibitor; prior chemotherapy or radiopharmaceutical therapy for mCRPC; uncontrolled type 1/2 diabetes; or active brain or leptomeningeal metastases. Primary endpoints for Phase 1 are safety and tolerability (incidence of DLTs, adverse events, and determination of maximum tolerated dose) determination of the recommended Phase 2 dose (RP2D), PK, and Bayesian Optimal Interval utility score. Primary endpoints for Phase 2 are rPFS rate at 6 months based on Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 with modifications as specified in Prostate Cancer Working Group 3 criteria. Secondary endpoints include rPFS rates at 9 and 12 months, overall rPFS, prostate-specific antigen response of ≥50% decrease from baseline at 4, 8, 12, and 16 weeks, overall response rate, duration of response, clinical benefit rate, overall survival rate at 18 and 24 months, and safety. The trial is currently open for enrollment. Citation Format: Adam Sharp, Alice Bernard-Tessier, Delphine Borchiellini, Johann de Bono, Karim Fizazi, Gwenaelle Gravis, David Lorente, Hakim Mahammedi, Begona Mellado, David Olmos, Simon Pacey, Jose Piulats, Sara P. Ramirez, Igor Gorbatchevsky, Elisabeth Heath. A phase 1/2, open-label, randomized, dose-finding and dose expansion study of gedatolisib in combination with darolutamide in metastatic castration-resistant prostate cancer (mCRPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT087.

Abstract CT262: A phase II basket trial of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART) SWOG S1609: sarcomatoid carcinoma of lung (cohort 11)

Abstract Background: Dual checkpoint inhibition with Anti-PD-1 and anti-CTLA4 checkpoint inhibitors have proven to be effective in several malignancies but their potential role in rare solid cancers is yet to be established. This study presents the first results of ipilimumab and nivolumab in the sarcomatoid carcinoma of lung cohort (#11) of the SWOG S1609 Dual Anti-CTLA-4 &amp; Anti-PD-1 blockade in Rare Tumors (DART) trial. Methods: DART is a prospective, open-label, multicenter/multi-cohort phase 2 clinical trial of ipilimumab (1mg/kg intravenously every 6 weeks) plus nivolumab (240mg intravenously every 2 weeks). The primary endpoint was objective response rate (ORR) (RECIST v1.1) (confirmed complete (CR) and partial responses (PR)); progression-free survival (PFS), overall survival (OS), stable disease (SD) &amp;gt;6 months, and toxicity are secondary endpoints. Results: Fourteen evaluable patients (median age, 64 years) with sarcomatoid carcinoma lung tumors were analyzed. ORR was 28.6% (4/14) with 1 CR and 3 PRs. The patient with CR has a duration of response (DoR) and OS of 32.4+ months. Three patients with PR showed 100% regression with resolution of one of two non-measurable non-target lesions (DoR 36.8 months), 92% regression (DoR 6.6 months), and 52% regression (DoR 23.0+ months), respectively. Clinical benefit rate (CBR; no progression &amp;gt; 6months) was 50.0% (7/14). The median PFS was 6.1 months, median OS was 10.9 months. The most common adverse events were fatigue and dyspnea (46.2%, n=6 each), and pruritus and hypothyroidism (30.8%, n=4 each). Grade 3-4 adverse events occurred in 30.8% of patients (n=4). There were no adverse events that led to discontinuation. There was one grade 5 adverse event due to respiratory failure. Conclusion: Ipilimumab plus nivolumab in sarcomatoid carcinoma of lung resulted in an ORR of 28.6% and CBR (SD&amp;gt;6 months/PR/CR) of 50.0%, with PFS of 36.9, 32.4+, 23.0+, 17.0, 13.3, 6.6, and 6.6 months. Correlative studies to determine response and resistance markers are ongoing. Expanded prospective studies are warranted. Citation Format: Young Kwang Chae, Megan Othus, Sandip Patel, Peeran Sandhu, Larry R. Corum, Jeremy P. Cetnar, Shayan Rayani, Anna Moseley, Liam Il-Young Chung, Hye Sung Kim, Christine M. McLeod, Helen X. Chen, Elad Sharon, Howard Streicher, Christopher W. Ryan, Charles D. Blanke, Razelle Kurzrock. A phase II basket trial of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART) SWOG S1609: sarcomatoid carcinoma of lung (cohort 11) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT262.

Abstract LB181: First disclosure of XRD-0394, a novel dual ATM/DNA-PK inhibitor, that potently radiosensitizes and potentiates PARP and topoisomerase inhibitors

Abstract A majority of cancer patients receive radiation therapy (RT) as part of their treatment regimens, whether using external beam therapy or locally-delivered radioisotopes. While often effective, RT may not be efficacious for some tumors while exerting significant short-term and long-term toxicities. Thus, enhancing therapeutic effectiveness of radiation therapy remains an important goal. ATM (ataxia-telangiectasia, mutated) and DNA-PKcs (deoxyribonucleic acid [DNA]-dependent protein kinase, catalytic subunit) are related protein kinases and both are critical regulators of cellular responses to ionizing radiation. We report here the identification and initial characterization of XRD-0394, a potent, specific dual inhibitor of both ATM and DNA-PKcs, whose chemical structure will be disclosed. A dual ATM/DNA-PK inhibitor has practical and theoretical advantages over compounds which inhibit just one of these kinases: 1) blunting both DNA damage response (DDR) pathways enhances radiation-induced tumor cell kill compared to single target inhibition; and 2) simultaneous inhibition of two DDR pathways should overcome intrinsic or acquired resistance of tumor cells to either target alone. Notably, transient inhibition of both kinases by XRD-0394 has little adverse effects on cells in the absence of irradiation. XRD-0394 is orally bioavailable, with excellent pharmacological profiles, demonstrating significant in vitro and in vivo sensitizing activity in combination with ionizing radiation and in combination with immunotherapy and radiation. In addition, a CRISPR screen identified alterations in the Fanconi A/BRCA pathway as an opportunity for synthetic lethality in tumor cells exposed to XRD-0394, an insight that was validated in multiple tumor cell types. In vitro studies demonstrated synergy of XRD-0394 in combination with PARP inhibitors, particularly in BRCA-mutant cells. XRD-0394 also potentiates the effectiveness of topoisomerase inhibitors in vitro. Single doses of XRD-0394 were well-tolerated in combination with palliative RT in subjects with advanced cancer in a Phase Ia clinical trial (NCT05002140). No DLTs were observed. At a dose of 160 mg, plasma concentrations were well above the preclinical target plasma level of 530 ng/mL (1 µM) for up to 15 h and inhibition of ATM kinase activity was demonstrated by inhibition of radiation-induced pKAP1 in tumor tissue. Importantly, this concentration of drug is sufficient to induce potent radiosensitization in numerous preclinical models. The median tmax (2.3 h) and mean terminal t½ (11.1 h) at the 160 mg dose in subjects support coadministration of XRD-0394 and RT within a clinically feasible time frame. These results provide a rationale for future clinical trials with XRD-0394 in combination with RT, RT and immunotherapy, PARP inhibitors and targeted delivery of topoisomerase inhibitors. Citation Format: Tona M. Gilmer, Chun-Hsiang Lai, Kexiao Guo, Katherine Deland, Kathleen A. Ashcraft, Amy E. Stewart, Yaode Wang, Jianmin Fu, Kris C. Wood, Deborah A. Smith, Jonathan T. Yang, Christopher T. Chen, Michael F. Gensheimer, Paul B. Romesser, Steven H. Lin, David G. Kirsch, Michael B. Kastan. First disclosure of XRD-0394, a novel dual ATM/DNA-PK inhibitor, that potently radiosensitizes and potentiates PARP and topoisomerase inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB181.

Abstract CT227: Anti-LAG-3 antibody LBL-007 in combination with anti-PD-1 antibody toripalimab, in patients with advanced malignant tumors: A phase Ib/II, open-label, multicenter, dose escalation/expansion study

Abstract Background: Dual inhibition of PD-1 and LAG-3 may have the potential to increase the immune response against tumor growth synergistically. Here we report the preliminary safety and efficacy results of LBL-007 (an anti-LAG-3 antibody) in combination with toripalimab (an anti-PD-1 antibody) in patients with advanced malignant tumors. Methods: Patients with advanced malignant tumors, including but not limited to nasopharyngeal carcinoma (NPC), non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), and head and neck squamous carcinoma (HNSCC), with or without prior anti-PD-(L)1 therapy, were enrolled. This trial was divided into two parts: phase Ib (dose escalation study), patients received LBL-007 at 200 mg or 400 mg plus toripalimab at 240 mg (both administered i.v. Q3W), and phase II (dose expansion), patients received LBL-007 at 400 mg and toripalimab at 240 mg (both administered i.v. Q3W). The primary objective was to assess safety and tolerability; the secondary objectives were to assess pharmacokinetics, pharmacodynamics, and preliminary efficacy (per RECIST 1.1). Results: By December 1, 2023, 80 patients were enrolled in phase Ib (10 patients) and phase II (70 patients). Of these, 30 (37.5%) were NPC patients, and 50 (62.5%) had other tumors. The median follow-up was 18.1 months (95% CI: 11.1, NE). No DLTs were observed in phase Ib. Seventy-three patients out of 80 (91.3%) experienced TEAEs of all grades, with 19 (23.8%) having grade ≥3 TEAEs. The most common any grade TEAEs (≥15%) were anaemia (40.0%), hypoalbuminaemia (18.8%), weight decreased (18.8%), hyponatremia (17.5%), proteinuria (17.5%), asthenia (17.5%), lymphocyte count decreased (16.3%), aspartate aminotransferase increased (16.3%), hypertriglyceridaemia (15.0%), and rash (15.0%). Treatment interruption and permanent discontinuation due to TEAEs occurred in 6 (7.5%) patients each. Sixteen patients (20.0%) experienced SAEs. Four patients experienced TEAEs leading to death, all events are related to underlying disease or disease progression, none of which were related to LBL-007 or toripalimab. Out of 75 efficacy evaluable patients, ORR and DCR were 13.3% (10/75) and 48.0% (36/75), respectively. In 29 efficacy evaluable NPC patients, ORR and DCR were 20.7% (6/29), and 62.1% (18/29), respectively. Among the group of 12 anti-PD-(L)1 treatment-naïve NPC patients and 17 anti-PD-(L)1 treated NPC patients, the ORR were 33.3% (4/12) and 11.8% (2/17), DCR were 75.0% (9/12) and 52.9% (9/17), respectively; Of note, the mPFS was up to 11.9 months (95%CI: 1.3, not reached) in anti-PD-(L)1 treatment-naïve NPC patients. Conclusions: LBL-007 in combination with toripalimab is well tolerated in patients with advanced malignant tumors and has demonstrated encouraging preliminary efficacy in patients with advanced NPC with or without prior anti-PD-(L)1 therapy. Clinical trial information: NCT05102006. Citation Format: Yunpeng Yang, Yuanyuan Zhao, Wenfeng Fang, Yan Huang, Yaxiong Zhang, Yi Ba, Zhen Wang, Chao Deng, Desheng Hu, Wei Wang, Guiling Li, Suxia Luo, Zhichao Fu, Haisheng Zhu, Huili Wang, Shiwei Zhao, Tao Li, Charles Cai, Li Zhang. Anti-LAG-3 antibody LBL-007 in combination with anti-PD-1 antibody toripalimab, in patients with advanced malignant tumors: A phase Ib/II, open-label, multicenter, dose escalation/expansion study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT227.

Potential role of lipophagy impairment for anticancer effects of glycolysis-suppressed pancreatic ductal adenocarcinoma cells

Although increased aerobic glycolysis is common in various cancers, pancreatic ductal adenocarcinoma (PDAC) cells can survive a state of glycolysis suppression. We aimed to identify potential therapeutic targets in glycolysis-suppressed PDAC cells. By screening anticancer metabolic compounds, we identified SP-2509, an inhibitor of lysine-specific histone demethylase 1A (LSD1), which dramatically decreased the growth of PDAC PANC-1 cells and showed an anti-tumoral effect in tumor-bearing mice. The growth of glycolysis-suppressed PANC-1 cells was also inhibited by another LSD1 inhibitor, OG-L002. Similarly, the other two PDAC cells (PK-1 and KLM-1) with suppressed glycolysis exhibited anticancer effects against SP-2509. However, the anticancer effects on PDAC cells were unrelated to LSD1. To investigate how PDAC cells survive in a glycolysis-suppressed condition, we conducted proteomic analyses. These results combined with our previous findings suggested that glucose-starvation causes PDAC cells to enhance mitochondrial oxidative phosphorylation. In particular, mitochondrial fatty acid metabolism was identified as a key factor contributing to the survival of PDAC cells under glycolysis suppression. We further demonstrated that SP-2509 and OG-L002 disturbed fatty acid metabolism and induced lipid droplet accumulation through the impairment of lipophagy, but not bulk autophagy. These findings indicate a significant potential association of lipophagy and anticancer effects in glycolysis-suppressed PDAC cells, offering ideas for new therapeutic strategies for PDAC by dual inhibition of glycolysis and fatty acids metabolism.