PI3K Mutations Research Articles

Afatinib plus bevacizumab combination after osimertinib resistance in advanced EGFR-mutant non-small cell lung cancer: Phase II ABCD-study

IntroductionMany clinical studies showed a synergy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) and vascular endothelial growth factor inhibitors. We hypothesized afatinib plus bevacizumab exerts clinical potency after developing various osimertinib resistant mechanisms. MethodsEGFR-mutant non-small cell lung cancer patients were enrolled after osimertinib resistance. Afatinib at 30–40 mg/day and bevacizumab at 15 mg/kg tri-weekly were administered until progression. Plasma/histologic rebiopsied samples after osimertinib failure were analyzed to examine resistant mechanisms: gene alterations/copy-number gain using cancer personalized profiling by deep sequencing. ResultsBetween January 2018 and October 2020, 28 patients were enrolled. Response and disease control rates were 17.9 % and 78.6 %, respectively. Median duration of response was 9.0 (range, 4.2–22.3) months. Median progression-free and overall survivals were 2.7 and 9.3 months, respectively. Twenty-eight (100 %) plasma and/or 21 (75 %) histologic rebiopsies identified: 17 (61 %) TP53; 15 (54 %) T790M; 9 (32 %) uncommon EGFR; 9 (32 %) MET; 6 (21 %) C797S; 3 (11 %) BRAF; 2 (7 %) HER2; 2 (7 %) KRAS; and 2 (7 %) PI3K mutations. One (17 %) of 6 C797S patients showed complete response. Three (33 %) of 9 uncommon EGFR-mutated patients achieved radiographic response. Neither 15 T790M-positive nor 6 EGFR downstream signaling mutations: BRAF; KRAS; or PI3K-positive patients responded, but 5 (38 %) of 13 T790M-negative patients responded. Adverse events ≥ grade 3 and incidence ≥ 5 % were: hypertension (29 %); proteinuria (7 %); and diarrhea (7 %). There were neither treatment-related death nor interstitial lung disease. ConclusionsSelected population could obtain clinical benefit from afatinib plus bevacizumab, based on rebiopsy results after osimertinib resistance.

Pathways to precision medicine: deciphering the secrets of physiological and pathological atrial enlargement.

Cardiac functional, morphological, and histological analysis, coupled with liquid chromatography and mass spectrometry, of two transgenic mouse models with cardiomyocyte-specific overexpression of insulin-like growth factor 1 receptor (IGF1R) or a dominant-negative PI3K mutant (DCM-dnPI3K) revealed distinctive functional and molecular profiles during physiological (driven by IGF1R overexpression) and pathological (driven by dn-PI3K overexpression) atrial remodeling. The current study confirmed previously reported findings, including ventricular dilatation and enhanced systolic function with no evidence of arrhythmia in IGF1R model, as well as ventricular hypertrophy and decreased systolic function with intermittent atrial fibrillation in DCM-dnPI3K model. Novel findings obtained from the left atrial (LA) characterization of female mice revealed that physiological atrial enlargement resulted from increased atrial myocyte size and was associated with preserved atrial function, as determined by maintained LA ejection fraction (EF). The proteomic profile of IGF1R transgenic (Tg) mice was enriched for metabolic remodeling and showed a protein expression pattern similar to that of healthy human atria; on the other hand, pathological atrial enlargement resulted from increased atrial fibrosis with normal myocyte size and was associated with impaired atrial function due to a reduced LA EF. The proteomic profile of DCM-dnPI3K mice was enriched to both metabolic and structural remodeling and showed a protein expression pattern similar to that of human AF atria.

Construction of amino acids reduced alphabets from molecular descriptors for interpretation of N-carbamylase, luciferase and PI3K mutations

The classification of amino acids has proven to be a useful tool for understanding the importance of sequence in protein function. The reduced amino acid alphabets are an example of these classifications, which, when built from physicochemical, structural and quantum characteristics of the amino acids, allow it to simplify the representation of the sequences, being useful in the modelling, design and understanding of proteins. So, an objective selection of amino acids properties is important, due classes formed in a reduced alphabet depend on the descriptors used for classification. In this research, based on a careful selection of descriptors for the 20 amino acids, through techniques such as the information content index and hierarchical cluster analysis with ties in proximity, 20,871,586 reduced amino acid alphabets were constructed. This large collection of reduced alphabets was been used to interpret alterations in the function of three proteins: N-carbamylase, Luciferase, and PI3K, caused by amino acid changes in their sequences. For this, the similar and different descriptors linked to these mutations were studied. Properties such as volume, hydrophobicity, charge and autocorrelation can be associated with variations in the behaviour of these proteins, while the frequency in specific secondary structures, the Gibbs free energy and some topological and quantum properties can be considered as the causes of preventing the deactivation of protein function. This work offers the most complete collection of reduced alphabets that promise to be a useful tool for the interpretation of alterations caused by amino acid mutations in the protein sequence.

Serabelisib, sapanisertib (PIKTOR) and paclitaxel: A combinatorial approach to improve PI3K/mTOR/AKT pathway inhibition and treatment response in solid tumors.

e15134 Background: Despite high mutation rates in genes of the PI3K/mTOR/AKT pathway in cancer, therapeutic strategies to inhibit this pathway featuring single targeted therapies have achieved limited clinical success. An alternate approach inhibiting multiple parts of the pathway simultaneously demonstrated improved activity (Starks et al, GynOnc 2022). The Phase 1 study combined the targeted PI3K-alpha and mTOR inhibitors serabelisib and sapanisertib (PIKTOR) with paclitaxel showing reasonable safety and promising clinical efficacy in patients with advanced endometrial, breast and ovarian tumors that had progressed on prior taxane. The ORR was 47% including 3 complete responses, with a PFS of 11 months in 15 evaluable subjects (NCT03154294). We sought to better understand the mechanistic basis for the efficacy of this triplet drug combination in models of endometrial and breast cancer to support successful clinical development of this regimen. Methods: Signaling activity in PI3K/mTOR/AKT pathway was probed by western blot for phospho-S6 and phospho-4EBP1 in human endometrial and breast cancer cell lines with PI3K/mTOR/AKT mutations. Single and combinatorial dose-response curves were established for serabelisib, sapanisertib and paclitaxel versus FDA-approved pathway inhibitors. Mechanisms of cytotoxicity and paclitaxel sensitization were probed with cell death assays. The impact of single and combined agents on tumor growth was assessed with in vivo xenograft studies. Results: In human endometrial and breast cancer cell lines, the combination of serabelisib and sapanisertib achieved markedly improved PI3K/mTOR/AKT pathway inhibition versus FDA-approved single agents. Serabelisib and sapanisertib increased the cytotoxicity of paclitaxel, supporting prior work that identifies PI3K/mTOR/AKT pathway activation as a key mediator of taxane resistance. Further, interrogation of a range of clinically relevant doses and scheduling led to an optimized regimen in which serabelisib and sapanisertib substantially improved the response to paclitaxel in vivo. Conclusions: Simultaneous inhibition of PI3K-alpha, mTORC1 and mTORC2 with PIKTOR offers potential for superior PI3K/mTOR/AKT pathway inhibition, suggesting that rational drug combination approaches may offer two important benefits: (1) more complete PI3K/mTOR/AKT pathway inhibition by targeting multiple signaling nodes, and (2) greater tumor cell cytotoxicity by sensitization to taxanes. These data, combined with the promising efficacy and safety signal from PIKTOR plus paclitaxel in a Phase 1 trial (NCT03154294), provide a compelling rationale for further clinical investigation. Future studies will focus on tumors known to have high rates of PI3K mutations including gynecologic tumors where there is a high unmet need.

Abstract PO4-01-02: High throughput analysis in HER2 positive locally advanced breast cancer: pCR and mutational status

Abstract Background Pathologic complete response (pCR) after neoadjuvant treatment (NAD) is a strong prognostic biomarker associated with improved survival in breast cancer patients, especially with HER2-positive and Triple negative subtypes. PIK3CA is mutated in up to 20% of HER2 positive breast cancers, contributes to anti-HER-2 resistance and may be predictive of the lack of response to anti HER2 NAD. PIK3CA mutations in breast cancer occur primarily at hotspots E545K at exon 9 and H1047R at exon 20. Next generation sequencing has improved our knowledge regarding the biology of the mechanisms behind treatment resistance. The aim of this study is to evaluate the genomic landscape of tissue samples obtained from locally advanced breast cancer patients treated in an neoadjuvant setting, in order to correlate the genomic analysis to response and clinical outcome. Methods DNA extracted from the archival 84 formalin-fixed paraffin-embedded (FFPE) samples from core needle biopsies was subjected to deep sequencing using the TruSight Oncology (TSO) 500 panel (Illumina, San Diego, USA; 523 genes, size: 1.94 Mb), following the manufacturer’s protocol, which assesses microsatellite instability (MSI) status, tumor mutation burden (TMB), recurrent somatic copy number variations (sCNV), somatic single nucleotide variants (SNVs). Libraries were sequenced on a NovaSeq 6000 instrument (Illumina) to reach a minimum of 500 × read depth. All samples were evaluated for RNA single cell transcriptional profile. 73 of 84 patients were treated with traditional neoadjuvant chemotherapy plus trastuzumab meanwhile 13 of 84 received neoadjuvant chemotherapy plus trastuzumab and pertuzumab. Statistical analysis was performed to detect the genes whose mutation involved in the progression and/or non-response of the disease using the Statistical Package for Social Science (SPSS), release 23.0. Continuous variables were expressed as mean ± SD or median [range], categorical variables were displayed as frequencies and the appropriate parametric (Student‘s t-test) non-parametric test (X2-test or Mann-Whitney test) was used to assess significance of the differences between subgroups (patients with or without pCR). Results In total we analyzed samples of 84 patients. The median age was 48 years. 64 of 84 (76.2%) were triple positive, 66 (78.6%) with G3 and 29 (34.5%) with stage III. The most common frequently mutated genes were PIK3CA (16/84, 19%) and BRCA1 (7/84, 8.3%). The pathogenic variant of BRCA1 (sBRCA1) had a significant association with resistance to treatment: we found a pCR in only 14.3% of sBRCA1 versus 62.3% in sBRCA1 wild type (wt) patients (p=0.014). We also identified 11 somatic mutations in hereditary genes (ATM, BRCA1, BRCA2, PALB2, CHEK2, RAD51C, RAD51D). From a germline standpoint we detected 7 pathogenic variants (two affecting BRCA1, two affecting CHEK2, one affecting PALB2, 7/84, 8.3%), which will be clinically confirmed. Among patients with a mutated PI3KCA, 43.8% obtained a pCR versus 61.8% of patients with PI3KCA wt (p=0.19). This data probably presents an imbalance due to the sample size A PTEN mutation was identified in 2% of pts (2/84) which obtained no benefit in terms of pCR after NAD versus 59.8% in wt patients (p=0.09). Conclusions In this preliminary report, genetic drivers such as BRCA1 status may have a clinical implication for prognosis and treatment response after NAD in locally advanced HER2 positive breast cancer. More samples are needed to evaluate the significance of PI3K and PTEN mutations in this patient setting. We are waiting for the results of the RNA single cell transcriptional profile of these samples. Event free survival data is not yet mature at this moment. We would like to acknowledge the contribution of Multi-specialistic Biobank Research Core Facility G-STeP, Fondazione Policlinico Universitario “A. Gemelli” IRCCS (Biobank-FPG) who provided the bio-resources. Citation Format: Ida Paris, Angelo Minucci, Daniele Generali, simona Nanni, Tatiana D'angelo, Francesco Pavese, Alessandra Fabi, Maria De Bonis, Katia Cannita, Alessia Piermattei, Giordana Tiberi, Paola Fuso, Luisa Carbognin, Silvia Rotondaro, Camilla Nero, Flavia Giacomini, Tina Pasciuto, Maria Marrazzo, Luciano Giaco', Antonino Mulè, Riccardo Masetti, Gianluca Franceschini, Giorgia Garganese, Diana Giannarelli, Giovanni Scambia. High throughput analysis in HER2 positive locally advanced breast cancer: pCR and mutational status [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-01-02.

Abstract ED10-01: PI3K past, present, and future

Abstract The PI3K pathway has long remained a fertile ground for drug discovery in cancer, including in estrogen receptor positive metastatic breast cancer. It has also remained a pathway difficult to drug effectively due to on target toxicities. New strategies to overcome these toxicities have manifested in novel drug types and management strategies for patients. Here I discuss the PI3K pathway in signaling and oncogenesis, current therapies inhibiting PI3K, mechanisms limiting efficacy, and increasing the PI3K therapeutic window with a focus on mutant selective PI3K inhibitors. Finally, I will expound on the translational future of the PI3K field, highlighting advances in biomarker discovery, tumor correlative analysis, and patient advocacy. Citation Format: N. Vasan. PI3K past, present, and future [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr ED10-01.

Abstract 393: RAS and PI3K activation promote glioblastoma progression and ischemia-associated tumor cell death

Abstract Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor in adults. Despite the association of tumor necrosis and a poor prognosis in GBM, the mechanisms underlying tumor necrosis formation remain unclear, likely due to the lack of appropriate experimental models to examine the development of tumor necrosis. In our study, we developed mouse models with tumor necrosis by intracranially injecting human GBM cells expressing KRAS or PI3K active mutants into immunodeficient mice. Surprisingly, despite all tumors displayed similar sizes, the control tumors expressing an empty vector (EV) did not exhibit tumor necrosis. This intriguing observation led us to explore the potential role of KRAS and PI3K in promoting cell death within the tumor microenvironment. Ischemia, which is characterized by insufficient nutrients and hypoxia, is often found in GBM. Under an in vitro ischemia mimetic condition, we found that the KRAS or PI3K activated GBM cells showed more cell death compared to EV cells. Mechanistically, ischemia activates the p38 MAPK-MK2 pathway to induce cell death, a process further enhanced by KRAS or PI3K. Notably, we observed elevated expression of p-MK2 in the peri-necrotic areas of GBMs harboring KRAS or PI3K mutants compared to the cellular tumor zones. Moreover, we revealed that ischemia induces the unfolded protein response (UPR) pathway. Among UPR-related molecules, KRAS and PI3K upregulate ERN1, which encodes the transmembrane protein kinase IRE1, in ischemic conditions. Inhibition of ERN1 not only prevented ischemia-induced cell death but also inhibited the p38 MAPK-MK2 pathway. Furthermore, we observed an increase in the expression of pro-inflammatory cytokine IL-8 under ischemic conditions, a response that was prevented by inhibitors of p38 MAPK or MK2. Lastly, we found that ischemia induces ATP release and calreticulin exposure, indicating the cell death possessing certain immunogenic cell death features. In summary, our findings revealed a pivotal role of KRAS and PI3K in inducing cell death in the ischemic GBM tumor microenvironment through activating the IRE1-p38 MAPK-MK2 pathway. The cell death under this circumstance displays pro-inflammatory and immunogenic properties. Therefore, the IRE1-p38 MAPK-MK2 pathway may be exploited for the treatment of GBM in which RAS or PI3K is activated. Citation Format: Soo Yeon Kim, Miaolu Tang, Stephen Chih, Jessica Thorpe, Tong Lu, Hong-Gang Wang, Wei Li. RAS and PI3K activation promote glioblastoma progression and ischemia-associated tumor cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 393.

A Pilot Study on BRCA1/2 and PI3K Mutations Across Subtypes of Triple Negative Breast Cancer in North Indian Population.

BRCA1/2 are tumor suppressor genes which regulate the DNA repair mechanism. Mutations in BRCA1/2 may increase the risk of breast cancer in patients. In the present study frequency of BRCA1/2 mutations in triple negative breast cancer (TNBC) patients was assessed and correlated with molecular subtypes of TNBC. Blood samples from 65 confirmed cases of TNBC were collected. DNA was isolated from whole blood and libraries were prepared using a BRCA1/2 custom panel. Sequencing was done on Ion torrent S5 sequencer and ion reporter was used for data analysis. Further molecular subtyping of mutation positive TNBC cases was done using immunohistochemistry markers CK5/6; CK4/14; Vimentin and E-Cadherin and androgen receptor (AR) using tissue microarray. Twenty five of 65 patients had heterozygous pathogenic mutations, alterations with conflicting interpretation of pathogenicity, variants of uncertain significance and variants of unknown significance. Nine patients had pathogenic mutation in BRCA 1 gene only and 2 patients had pathogenic mutations in BRCA2 gene. Two patients were transheterozygous for BRCA mutations, that is, had pathogenic mutations in both BRCA1/2 genes simultaneously and 5 were compound heterozygous (involving BRCA2 gene in all the cases). Prevalent subtypes among BRCA positive cases were unclassified subtype (n=4, 33%), Basal like (n=5, 41%), and mesenchymal subtype (n=3, 25%). None of the LAR subtype showed BRCA1/2 mutations. The present study observed that the BRCA1 mutation is more frequent than BRCA2 mutation in TNBC. BRCA1/2 mutations do not correspond to BRCAness or basal phenotype. Considering high incidence of breast cancer and lack of correlation of basal morphology with BRCA1/2 mutation, the molecular methods should be used for screening for BRCA1/2 mutations. This will not only help in familial screening but also in deciding targeted therapy with PARP (poly-ADP ribose polymerase) inhibitors.

Designing an Inhibitor Molecule to Combat Cancer through the Inhibition of Mutant PI3K (P110 α) Subunit Protein

The PI3K pathway plays a crucial role in the development of various types of cancers. Specifically, the P110 α component is frequently modified in the formation of human cancer, leading to disruptions in cell growth regulation and the emergence of malignancies. This research paper delves into the increasing utilization of computational tools to forecast potential molecules capable of inhibiting cancer. To validate stable structures of PI3K (P110α) component protein models, the study employed Ramachandran map analysis, which revealed active regions in close proximity to the mutation site. Through the employment of PyRX software, molecular docking studies were conducted, resulting in the identification of four inhibitor derivatives that exhibited significant effectiveness with the lowest docking energies in preventing the mutated PI3K (P110 α) component protein structures. Furthermore, these inhibitors adhered to Lipinski's rule of five, further enhancing their potential.

SOS1 and KSR1 modulate MEK inhibitor responsiveness to target resistant cell populations based on PI3K and KRAS mutation status.

KRAS is the most commonly mutated oncogene. Targeted therapies have been developed against mediators of key downstream signaling pathways, predominantly components of the RAF/MEK/ERK kinase cascade. Unfortunately, single-agent efficacy of these agents is limited both by intrinsic and acquired resistance. Survival of drug-tolerant persister cells within the heterogeneous tumor population and/or acquired mutations that reactivate receptor tyrosine kinase (RTK)/RAS signaling can lead to outgrowth of tumor-initiating cells (TICs) and drive therapeutic resistance. Here, we show that targeting the key RTK/RAS pathway signaling intermediates SOS1 (Son of Sevenless 1) or KSR1 (Kinase Suppressor of RAS 1) both enhances the efficacy of, and prevents resistance to, the MEK inhibitor trametinib in KRAS-mutated lung (LUAD) and colorectal (COAD) adenocarcinoma cell lines depending on the specific mutational landscape. The SOS1 inhibitor BI-3406 enhanced the efficacy of trametinib and prevented trametinib resistance by targeting spheroid-initiating cells in KRASG12/G13-mutated LUAD and COAD cell lines that lacked PIK3CA comutations. Cell lines with KRASQ61 and/or PIK3CA mutations were insensitive to trametinib and BI-3406 combination therapy. In contrast, deletion of the RAF/MEK/ERK scaffold protein KSR1 prevented drug-induced SIC upregulation and restored trametinib sensitivity across all tested KRAS mutant cell lines in both PIK3CA-mutated and PIK3CA wild-type cancers. Our findings demonstrate that vertical inhibition of RTK/RAS signaling is an effective strategy to prevent therapeutic resistance in KRAS-mutated cancers, but therapeutic efficacy is dependent on both the specific KRAS mutant and underlying comutations. Thus, selection of optimal therapeutic combinations in KRAS-mutated cancers will require a detailed understanding of functional dependencies imposed by allele-specific KRAS mutations.

Preclinical evidence for synergistic effects of autophagy inhibitor and alpelisib in PI3KCA mutated non-small cell lung cancer: Implications for future clinical trials.

e21022 Background: The PI3K pathway is frequently activated in a variety of cancers including non-small cell lung cancer (NSCLC). PI3K mutation is associated with worse response to chemotherapy and consequently decrease the effectiveness of single administration of anticancer drugs. In this study, we checked the therapeutic efficacy of alpelisib either alone or in combination with an autophagy inhibitor for the treatment of NSCLC. Methods: We treated alpelisib and autophagy inhibitors in human NSCLC cell lines and measured the cell viability and protein expression of autophagy indicators, p62 and LC3B. Co-treatment of alpelisib and autophagy inhibitors significantly decrease the cell viability and proliferation compared to alpelisib alone. Based on the results of the combination experiment of alpelisib and autophagy inhibitors, Chloroquine (CQ) was selected for further study. Co-treatment of alpelisib and CQ significantly increase apoptosis and decrease tumor-related protein expression in in vitro and in vivo. Results: Our data demonstrates that alpelisib and autophagy inhibitor have a synergistic efficacy against NSCLC in vitro and in vivo. Conclusions: Based on these results, a Phase 1 clinical trial is currently being planned.

Intermittent or continuous panitumumab plus FOLFIRI (FOLFIRI/PANI) for first-line treatment of patients (pts) with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC): An update of survival/toxicity and preliminary results of genomic alterations from IMPROVE study.

3571 Background: IMPROVE is a randomized, non-comparative multicenter, phase 2 study which evaluated continuous, until progressive disease (PD), or intermittent FOLFIRI/PANI, in pts with unresectable and previously untreated RAS/BRAF wt mCRC. In the intermittent schedule 8 cycles were followed by a treatment free interval lasting until PD when another 8 cycles were restarted, continuing this strategy until PD occurred on treatment. Primary endpoints was progression-free survival on treatment (PFSOT) at 1 year. In a previous analysis the primary endpoint of the study was met and a reduced skin toxicity was observed in the intermittent arm. Here we report an updated analysis. Methods: Updated analysis includes PFSOT and toxicity with 9 months (mo) of additional follow-up. Moreover we report overall survival (OS), skin toxicity burden (STB) score and preliminary data on genomic alterations (GAs) in 46 pts with PD. STB score, incorporating both the frequency and the severity of skin toxicity, was obtained by summing all grades that the pts experienced across all treatment cycles. GAs were performed by NGS on circulating tumor DNA (ctDNA) from paired plasma samples (baseline and progression), focusing specifically on RAS, BRAF and PI3K mutations. Results: Pts received FOLFIRI/PANI continuously (arm A, 69 pts) or intermittently (arm B, 67 pts). Median number of FOLFIRI/PANI cycles administered per pt were (arm A/B) 13/16. In arm B, after induction treatment, 24/53 pts (45%) without PD had ≥ 2 rounds of 8 FOLFIRI/PANI cycles. ORR (arm A/B) was 63/57%. At a median follow-up of 28 mo (IQR: 21-37), median PFSOT (77% of events) was 11.4 mo (95% CI: 9.1-13.7) in arm A, and 18.1 mo (95% CI: 6.8-29.3) in arm B. Median PFSOT in left sided tumors was 11.7 mo (95% CI: 9.1-14.3) in arm A and 23.9 mo (95% CI: 15.0-32.9) in arm B, compared with 10.7 mo (95% CI: 7.3-14.1) and 7.9 mo (95% CI: 5.7-10.1) in right sided pts, respectively. OS (46% of events) was 31.0 mo (95% CI: 24.7-37.2) in arm A and 32.2 mo (95% CI: 23.6-40.8) in arm B. Main grade ≥ 3 toxicities were (arm A/B): skin 30/18%, neutropenia 25/24%; diarrhea 13/15%. Median STB score was 0.77/cycle (IQR: 0.20-1.06) in arm A and 0.36/cycle (IQR: 0-0.77) in arm B. GAs in baseline ctDNA were evidenced in 12/46 (26%) pts, persisting to PD in all but one pt. Among the 34 pts without baseline GAs, only 8 (23%) developed ≥ 1 acquired GAs (Acq-GAs) to PD. Conclusions: Updated analyses confirmed that intermittent FOLFIRI/PANI strategy produces a long PFSOT and a reduced skin severe and skin burden toxicity without any detrimental effect on OS. Preliminary data on Acq-GAs suggest that classical mutations associated with anti-EGFR resistance are infrequent with up-front use of anti-EGFR/chemotherapy. Clinical trial information: NCT04425239 .

MP17-20 EPIGENETIC REGULATOR KMT2C MUTATION DETECTED BY LIQUID BIOPSY IS ASSOCIATED WITH WORSE SURVIVAL IN PROSTATE CANCER PATIENTS

You have accessJournal of UrologyCME1 Apr 2023MP17-20 EPIGENETIC REGULATOR KMT2C MUTATION DETECTED BY LIQUID BIOPSY IS ASSOCIATED WITH WORSE SURVIVAL IN PROSTATE CANCER PATIENTS Sha Zhu, Nanwei Xu, Fengnian Zhao, Zilin Wang, Yuchao Ni, Jindong Dai, Jinge Zhao, Jiayu Liang, Xingming Zhang, Junru Chen, Pengfei Shen, and Hao Zeng Sha ZhuSha Zhu More articles by this author , Nanwei XuNanwei Xu More articles by this author , Fengnian ZhaoFengnian Zhao More articles by this author , Zilin WangZilin Wang More articles by this author , Yuchao NiYuchao Ni More articles by this author , Jindong DaiJindong Dai More articles by this author , Jinge ZhaoJinge Zhao More articles by this author , Jiayu LiangJiayu Liang More articles by this author , Xingming ZhangXingming Zhang More articles by this author , Junru ChenJunru Chen More articles by this author , Pengfei ShenPengfei Shen More articles by this author , and Hao ZengHao Zeng More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003237.20AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: KMT2 (lysine methyltransferase) family enzymes exert epigenetic regulation to active gene transcription. KMT2C are mainly involved in enhancer-associated H3K4me1, and is also the top mutated genes in cancer (6.6% in pan-cancer). Currently, the clinical significance of KMT2C mutations in prostate cancer is understudied. METHODS: We included 221 prostate cancer patients diagnosed between 2014 and 2021 in West China Hospital of Sichuan University with cfDNA-based liquid biopsy test results in this study. We explored the association of KMT2C mutations with other mutations and investigates the prognostic significance of KMT2C mutation measured by overall survival (OS) and castration-resistance free survival (CFS). In addition, we explored the prognostic value of KMT2C mutation in different patient subgroups. RESULTS: The KMT2C mutation rate in this cohort is 7.24% (16/221). KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CFS and OS (CFS: mutated: 9.9 vs. WT: 22.0 months, p=0.015; OS: mutated: 71.9 vs. WT 137.4 months, p=0.012). KMT2C mutation was also an independent risk factor in OS [HR: 3.815 (1.461, 9.96), p=0.006] in multivariate analyses. Besides, we also explored the association of KMT2C mutations and other genes, and the results showed that KMT2C mutation was related to Serine/Threonine-Protein Kinase 11 (STK11, p=0.004) and Catenin Beta 1 (CTNNB1, p=0.008) mutations. For OS, KMT2C mutation was significantly associated with survival in patient subgroups with PI3K pathway mutation (HR: 6.64, p=0.009) or WNT pathway mutation (HR: 2.44, p=0.043). CONCLUSIONS: KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CFS and OS, and KMT2C mutation was associated with STK11 and CTNNB1 mutations. Furthermore, KMT2C mutation was significantly associated with survival in certain patient subgroups, such as patients with PI3K and WNT pathway mutation, etc. Source of Funding: The Natural Science Foundation of China (NSFC 81902577); The Research Foundation for the Postdoctoral Program of Sichuan University (2021SCU12014) © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e221 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sha Zhu More articles by this author Nanwei Xu More articles by this author Fengnian Zhao More articles by this author Zilin Wang More articles by this author Yuchao Ni More articles by this author Jindong Dai More articles by this author Jinge Zhao More articles by this author Jiayu Liang More articles by this author Xingming Zhang More articles by this author Junru Chen More articles by this author Pengfei Shen More articles by this author Hao Zeng More articles by this author Expand All Advertisement PDF downloadLoading ...

Activating mutations in EGFR and PI3K promote ATF4 induction for NSCLC cell survival during amino acid deprivation

Some oncoproteins along with stress kinase general control non-derepressible 2 (GCN2) can ensure the induction of activating transcription factor 4 (ATF4) to counteract amino acid deprivation; however, little is known regarding the role of the oncogenic EGFR-PI3K pathway. In this study, we demonstrate that both mutated EGFR and PIK3CA contribute to ATF4 induction following GCN2 activation in NSCLC cells. The inhibition of EGFR or PI3K mutant proteins, pharmacologically or through genetic knockdown, inhibited ATF4 induction without affecting GCN2 activation. A downstream analysis revealed that the oncogenic EGFR-PI3K pathway may utilize mTOR-mediated translation control mechanisms for ATF4 induction. Furthermore, in NSCLC cells harboring co-mutations in EGFR and PIK3CA, the combined inhibition of these oncoproteins markedly suppressed ATF4 induction and the subsequent gene expression program as well as cell viability during amino acid deprivation. Our findings establish a role for the oncogenic EGFR-PI3K pathway in the adaptive stress response and provide a strategy to improve EGFR-targeted NSCLC therapy.

Abstract P3-11-03: Novel Targeting of Semaphorin 7a-Mediated Survival Signaling in ER+ Breast Cancer

Abstract Endocrine receptor-positive (ER+) breast cancers (BC) comprise over 70% of all breast cancers and are the leading cause of BC-related deaths in women. Despite available targeted therapies against ER+ BC, recurrence arises primarily due to the development of endocrine therapy resistance and metastases. Thus, there is an unmet need to identify novel biomarkers for treating ER+ BC patients with metastases. We have identified a neuroimmune molecule, Semaphorin 7a (SEMA7A), as a potential biomarker for endocrine therapy resistance, increased relapse and decreased overall survival in ER+ BC patients. We have also found that SEMA7A promotes tumor growth, angio- and lymphangiogenesis, epithelial-to-mesenchymal transition (EMT), metastasis and endocrine therapy resistance in pre-clinical models. Specifically, we have shown that SEMA7A+ ER+ MCF7 tumors result in lung metastases that are resistant to the endocrine therapy, fulvestrant, in part, via downregulation of ER in vivo – posing the need to identify novel, druggable targets for SEMA7A+ ER+ BC. SEMA7A is a membrane-bound protein that we have shown can inhibit tumor cell death via integrin-mediated activation of PI3K/Akt pro-survival signaling. Thus, we hypothesized that that SEMA7A+ ER+ BC cells may be sensitive to PI3K inhibition in combination with fulvestrant. Our results demonstrate that SEMA7A+ MCF7 cells are sensitive to the combination of fulvestrant and PI3K inhibition by alpelisib, which is FDA approved for ER+ BC patients with activating mutations in PI3K; this combination also inhibited tumor cell growth and decreased tumor sphere formation. In complementary studies, we identified that Singleminded 2s (SIM2s), which is expressed in breast epithelial cells and inhibits EMT, is downregulated SEMA7A+ MCF7 tumors. Additionally, our studies show that while ER-mediated signaling turns on SEMA7A expression prolonged expression of SEMA7A results in downregulation of ER, and the loss of SIM2s causes downregulation of ER expression and upregulation of SEMA7A in MCF7 cells. Further, while SEMA7A-overexpressing (OE) tumor cells exhibit increased tumor-promoting PI3K/Akt survival signaling, we found that SIM2s plays a role in suppression of PI3K/Akt survival signaling. Therefore, we are investigating the interactions between SIM2s, SEMA7A and the survival signaling pathways involved in their crosstalk. Our recent results show that MCF7 SIM2-knockout (KO) cells exhibit increased SEMA7A promoter activity, SEMA7A expression, activation of Akt signaling, EMT phenotypes and decreased ER expression. Also, addition of exogenous SEMA7A protein reduces SIM2s expression and promoter activity. Since SIM2s correlates with inhibition of PI3K/Akt signaling and decreased SEMA7A, and SEMA7A promotes survival signaling, we are investigating additional therapeutic strategies to prevent endocrine therapy resistance via direct inhibition of SEMA7A and/or restoration of SIM2s, including inhibition of COX-2 and Akt signaling. Citation Format: Rachel Steinmetz, Garhett Wyatt, Traci Lyons, Weston Porter, Lyndsey Crump. Novel Targeting of Semaphorin 7a-Mediated Survival Signaling in ER+ Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-11-03.

Abstract P1-13-04: Potentiating Alpelisib in PI3K Pathway Overactive Triple Negative Breast Cancers

Abstract Potentiating Alpelisib in PI3K Pathway Overactive Triple Negative Breast Cancers David C. Boyd1,2, Amy L. Olex3, Tess Leftwich1, Nicole Hairr1, Alex K. Duong1, Narmeen S. Rashid1,3, Mohammad A Alzubi1,2, Holly Byers1, Aaron D. Valentine1, Julia E. Altman1, Emily Zboril1, Jacqueline M. Grible1, Madelyn Esquivel1, Scott A. Turner1, Andrea Ferreira-Gonzalez1, Mikhail G. Dozmorov5, J. Chuck Harrell1,2,6 1Department of Pathology, Virginia Commonwealth University; 2Integrative Life Sciences Program, VCU; 3Wright Center for Clinical and Translational Research, VCU; 4Department of Biology, University of Richmond; 5Department of Biostatistics, VCU; 6Massey Cancer Center, VCU. There is an urgent need for new therapeutic options for basal-like Triple Negative Breast Cancers (TNBC). To mirror the NCI-ComboMATCH study, and identify new synergistic drug combinations, we analyzed a set of 20 breast cancer patient-derived xenografts and 14 cell lines to identify targetable targets in each model. The Oncomine Comprehensive Assay v3 was performed to assess 161 genes for hotspot mutations, focal copy number variants, amplification/deletions, and RNA-fusion genes. Next, each PDX and their isogenic drug-resistant sublines were analyzed with bulk RNA-sequencing (217 samples) and cell single-cell RNA-sequencing (~100,000 cells). Of all NCI-MATCH defined targetable mutations, 37% of the models contained pathogenic PIK3CA amplifications or mutations. PIK3CA is one of the most common oncogenic aberrations identified in patients and the PI3K pathway is overactive in the majority of TNBCs, therefore we sought to target it across all models and identify the most efficacious synergistic drug partner. Short-term cultures of each PDX model were screened with a library of >1,000 FDA-approved/experimental drugs to identify compounds that were cytotoxic. Synergistic drug screens were then performed with each drug in combination with the PI3K inhibitor byl-719 (alpelisib) a current standard-of-care drug used for PI3K mutant ER+ disease. Synergism was identified using coefficient of drug interaction (CDI) calculations and 10 drugs were identified as synergistic across several models. Using several criteria, including clinical status and pathway analysis, 3 drugs were selected for CompuSyn-based synergism testing and each was confirmed to be synergistic in vitro. Testing with in vivo models of each drug combination has thus far confirmed that each is synergistic per CDI metrics. Those combinations are currently being tested for efficacy in the metastatic setting with a set of basal-like PDXs. Citation Format: David Boyd, Chuck Harrell. Potentiating Alpelisib in PI3K Pathway Overactive Triple Negative Breast Cancers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-04.

Role of epigenetic regulator KMT2C mutation detected by liquid biopsy in survival in patients with prostate cancer.

222 Background: KMT2 (lysine methyltransferase) family enzymes exert epigenetic regulation to active gene transcription. KMT2C is mainly involved in enhancer-associated H3K4me1 and is also the top mutated gene in cancer (6.6% in pan-cancer). Currently, the clinical significance of KMT2C mutations in prostate cancer is understudied. Methods: We included 221 prostate cancer patients diagnosed between 2014 and 2021 in West China Hospital of Sichuan University with cfDNA-based liquid biopsy test results in this study. We explored the association of KMT2C mutations with other mutations and investigates the prognostic significance of KMT2C mutation measured by overall survival (OS) and castration-resistance free survival (CFS). In addition, we explored the prognostic value of KMT2C mutation in different patient subgroups. Results: The KMT2C mutation rate in this cohort is 7.24% (16/221). KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CFS and OS (CFS: mutated 9.9 vs. WT 22.0 months, p=0.015; OS: mutated 71.9 vs. WT 137.4 months, p=0.012). KMT2C mutation was also an independent risk factor in OS [HR: 3.815 (1.461, 9.96), P=0.006] in multivariate analyses. Besides, we also explored the association of KMT2C mutations and other genes, and the results showed that KMT2C mutation was related to Serine/Threonine-Protein Kinase 11 ( STK11, p=0.004) and Catenin Beta 1 ( CTNNB1, p=0.008) mutations. For OS, KMT2C mutation was significantly associated with survival in patient subgroups with PI3K pathway mutation (HR: 6.64, p=0.009) or WNT pathway mutation (HR: 2.44, p=0.043). Conclusions: KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CFS and OS, and KMT2C mutation was associated with STK11 and CTNNB1 mutations. Furthermore, KMT2C mutation was significantly associated with survival in certain patient subgroups, such as patients with PI3K and WNT pathway mutation, etc.

Dysregulation of Mitochondrial Translation Caused by CBFB Deficiency Cooperates with Mutant PIK3CA and Is a Vulnerability in Breast Cancer.

CBFB-regulated mitochondrial translation is a regulatory step in breast cancer metabolism and synergizes with mutant PI3K in breast cancer progression.

Metastatic Breast Cancer to the Spine: Incidence of Somatic Gene Alterations and Association of Targeted Therapies With Overall Survival.

The increase in use of targeted systemic therapies in cancer treatments has catalyzed the importance of identifying patient- and tumor-specific somatic mutations, especially regarding metastatic disease. Mutations found to be most prevalent in patients with metastatic breast cancer include TP53, PI3K, and CDH1. To determine the incidence of somatic mutations in patients with metastatic breast cancer to the spine (MBCS). To determine if a difference exists in overall survival (OS), progression-free survival, and progression of motor symptoms between patients who do or do not undergo targeted systemic therapy after treatment for MBCS. This is a retrospective study of patients with MBCS. Review of gene sequencing reports was conducted to calculate the prevalence of various somatic gene mutations within this population. Those patients who then underwent treatment (surgery/radiation) for their diagnosis of MBCS between 2010 and 2020 were subcategorized. The use of targeted systemic therapy in the post-treatment period was identified, and post-treatment OS, progression-free survival, and progression of motor deficits were calculated for this subpopulation. A total of 131 patients were included in the final analysis with 56% of patients found to have a PI3K mutation. Patients who received targeted systemic therapies were found to have a significantly longer OS compared with those who did not receive targeted systemic therapies. The results of this study demonstrate that there is an increased prevalence of PI3K mutations in patients with MBCS and there are a significant survival benefit and delay in progression of motor symptoms associated with using targeted systemic therapies for adjuvant treatment.

Analysis Of Common Somatic Mutations In Colorectal Carcinoma And Associated Dysregulated Pathwaysarts.

Identification of gene targets and biological pathways involved in colorectal carcinoma (CRC) is essential for better management of patients. Our study aims to highlight common somatic mutations in colorectal carcinoma and to identify dysregulated pathways and gene enrichment based on KRAS and BRAF interaction network analysis. By using cancer browser tool in COSMIC database, mutation frequencies of the top 20 mutated genes listed for colorectal adenocarcinoma were identified. The most frequent variants of selected genes were explored with ClinVar database which led to identification of protein change along with its cytogenic location, variant type, variant length and the associated single nucleotide polymorphism (SNP). These identified SNPs were searched in Pakistani database using 1000genome in an attempt to identify common polymorphisms. Using the database ClinicalTrial.gov the number of clinical trials based upon these selected mutations was explored. Enrichment and protein interaction (PI) analysis of KRAS and BRAF was carried out to reveal significant biological pathways associated with these genes. In cumulative data, among all variants about 57% of substitution mutations are observed to be G>A including mutations in KRAS, Tp53, SMAD4, PI3K and NRAS. The mutations of KRAS (c.35G>A), TP53 (c.524G>A) and APC (c.4348C>T) were found to be pathogenic with single nucleotide variation and variant length of 1bp. Searching 1000genome database revealed that 100 % of alleles found in East Asian population studied are 'C'(frequency=1). Significant biological pathways (<0.05) identified by our search include Trk receptor signalling mediated by the MAPK pathway, signalling to p38 via RIT and RIN, signalling to ERKs, Frs2-mediated activation, ARMS-mediated activation and prolonged ERK activation events. Our study highlights the role of genetic profiling in CRC, with emphasis on mutations which may define treatment outcome. Targeting several collateral pathways simultaneously may be further explored to improve colorectal cancer therapeutics.