John, August

Abstract Background: Approximately 70% of breast cancers are estrogen receptor-positive (ER+), and endocrine therapies, including selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs), are standard-of-care. However, interpatient variability in treatment response and relapse remains substantial, suggesting underlying germline pharmacogenomic factors that modify ER signaling. Here, we mapped ER pharmacogenomic eQTLs to identify germline variants that modulate transcriptional responses to estradiol (E2) and tamoxifen (Tam). Methods: We treated 30 genotyped lymphoblastoid cell lines (LCLs) with vehicle, E2, Tam, or E2+Tam and performed RNA-seq to quantify ligand-induced expression fold changes. Using MatrixEQTL, we identified SNP-gene PGx-eQTLs (cis, ±200 kb), requiring evidence of ER transcriptional specificity via (i) reversal by dual treatment, and (ii) overlap with ER ChIP-seq binding annotations. Clinical relevance was assessed by linkage to breast cancer GWAS datasets, including NSABP, MA.27, and M3. Chromatin regulatory states were annotated (ChromHMM), and transcription factor motif enrichment was performed from SNP-centered ±200 bp regions. Results: Distinct PGx-eQTL architectures were identified for E2 and Tam, with partial overlap in ligand-responsive loci. ER PGx-eQTL variants were predominantly enriched in enhancer chromatin and co-localized with canonical ER-binding motifs. Integrative analysis with GWAS of breast cancer outcomes highlighted multiple drug-response-associated loci, including rs311392-MRPL15 and rs7953325-SYCP3. High MRPL15 expression was linked to shorter relapse-free survival, whereas high SYCP3 expression correlated with improved outcomes. Additional loci derived from a GWAS catalog for cancer and hormone phenotypes included rs2850247-SIK2 and rs11673604-LSM4, where higher SIK2 expression was associated with improved relapse-free survival and higher LSM4 expression with poorer outcomes. Conclusions: We identified ligand-dependent ER PGx-eQTLs that mechanistically connect germline regulatory variants to transcriptional response heterogeneity and clinical endocrine therapy outcomes. These SNP-gene relationships represent potential biomarkers for precision endocrine therapy selection and may reveal endocrine-dependent therapeutic vulnerabilities. Citation Format: Martin Meng, Huanyao Gao, August John, Arnab Ghosh, Shreya Indulkar, Liewei Wang, . Estrogen receptor-mediated pharmacogenomic eQTLs as predictors of endocrine therapy response in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3610.

Background: Prostate cancer is the most common cancer in men in the United States with an estimated 288,300 new cases diagnosed in 2023. The treatment strategies include androgen deprivation therapies (ADTs) for metastatic prostate cancer (mPC) but 10-20% of patients eventually progress to castration-resistant prostate cancer (CRPC). However, nearly all patients develop primary and acquired resistance overtime, and developing therapies and identifying novel molecular targets are essential in enhancing the clinical outcomes of patients with prostate cancer. In this study, we report a small molecule that belongs to a class of tricyclic quinolones, QL47 that was previously screened among various other compounds in prostate PDX organoid models and showed a potent anti-proliferative activity. Methods: QL47 was tested on prostate cancer cell lines (22Rv1, 22RV1 abiraterone-resistant and DU145) for its anti-proliferative potential. Further, we used the biotinylated QL47 (QL47B) to pulldown its potential targets and we identified the targets through immunoprecipitation-mass spectrometry (IP-MS) technique followed by Western blot analysis. Cell cycle and cell death analyses were performed after staining the cells with propidium iodide and Annexin V followed by flow cytometry analysis. Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) was investigated using the Seahorse assay. Results: The initial screening of QL47 in prostate cancer cell lines showed that it inhibits the proliferation at an IC50 of 50-200 nM. Through IP-MS and Western blot analysis, we identified a member of the pyruvate dehydrogenase complex dihydrolipoamide S-acetyltransferase (DLAT) as a direct target of QL47. Mechanistically, we found that QL47 does not increase cell death or affect cell cycle, but inhibits metabolic function, with a decrease in both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Conclusion: We have identified a novel mechanism of action of QL47 on the pyruvate dehydrogenase complex, and we plan to further validate the safety and efficacy for the treatment of prostate cancer. Citation Format: Grace Nirmala Jesuthankaraj, August John, Huanyao Gao, Arun Kanakkanthara, Richard Weinshilboum, Liewei Wang. Targeting metabolic dysfunction in prostate cancer: the anti-proliferative effects of ql47 through inhibition of dlat [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4297.

Most patients with metastatic prostate cancer eventually develop resistance to primary androgen deprivation therapy. To identify predictive biomarker for Abiraterone acetate/prednisone resistance, we screened alternative splice variants between responders and non-responders from the PROMOTE clinical study and pinned down the most significant variant, CENPK–delta8. Through preclinical patient-derived mouse xenograft (PDX) and 3D organoids obtained from responders and non-responders, as well as in vitro models, aberrant CENPK–delta8 expression was determined to link to drug resistance via enhanced migration and proliferation. The FLNA and FLOT1 were observed to specifically bind to CENK–delta8 rather than wild-type CENPK, underscoring the role of CENPK–delta8 in cytoskeleton organization and cell migration. Our study, leveraging data from the PROMOTE study, TCGA, and TCGA SpliceReq databases, highlights the important function of alternative splice variants in drug response and their potential to be prognostic biomarkers for improving individual therapeutic outcomes in precision medicine.

Abstract BACKGROUND: Cancer is typically treated with a combination of drugs rather than monotherapy stratagems, but identification of synergistic drug combinations for the treatment of cancers is challenging. Here we present the combination of PARP and Aurora Kinase inhibitors synergize through induction of the ferroptosis pathway of cell death. METHODS: We identified these drugs through an unbiased screen of enriched drug class response correlations. We then validated a synergistic cell killing effect of multiple drugs of each class by in vitro drug screening. Next, we performed reversal experiments using a ferroptosis inhibitor and lipid peroxide staining to confirm ferroptosis is a relevant cell death pathway. We performed Western immunoblot analysis in cells overexpressing putative Aurora Kinase phospho-substrates in the relevant pathway of interest, and performed site directed mutagenesis experiments to show the relevant amino acid altered by kinase activity. We also performed a series of qPCR and co-IP experiments to show PARPi effect on the antioxidant signaling pathway. RESULTS: We validated and identified synergy in a prostate cancer specific context. Next, we found Talazoparib and Alisertib induced ferroptosis after synergy was reduced with a ferroptosis inhibitor and lipid peroxides increased accumulation. We found a novel mechanism action for Alisertib, wherein Aurora Kinase inhibitors can alter the phospho-status and activity of the iron reduction enzyme Steap3.We also found that PARP inhibitors can affect the Nrf2-driven antioxidant signaling pathway on a transcriptional level. CONCLUSION: Aurora Kinase inhibitors and PARP inhibitors for the treatment of prostate cancer was identified and was validated as synergistic, which revealed new functional roles of both drugs in the context of cell killing. These findings represent a new clinical combination of drugs in prostate cancer and reveal a novel role for this drug class in ferroptosis. Citation Format: August John, Kuntian Luo, Zhenkun Lou, Liewei Wang. Ferroptotic mechanism of drug induced toxicity of PARPi and AurKi in prostate cancer [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 4563.

Abstract Background: Cancer is usually treated with a combination of drugs rather than a single agent. Treating cancer with a drug combination decreases the likelihood of the cancer acquiring resistance to therapy. It also allows for lower dosages of individual drugs, which reduces the occurrence and severity of side effects. Using public datasets, we investigated potential anti-cancer drug combinations using a novel framework, ReCorDE (Recurrent Correlation of Drugs with Enrichment), which identifies correlated drug response patterns for drugs with different primary mechanisms of action. Methods: 250 drugs from CTRPv2, GDSCv2, and PRISM datasets were examined using normalized logIC50 or AUC measurements. ReCorDE consists of a correlation and an enrichment step. For each dataset, we constructed pairwise drug-drug relationships using Spearman’s correlation. Combinations significant (p < 0.05) in less than two datasets after Benjamini-Hochberg (BH) correction were pruned. To turn each drug combination into a drug class combination, all drugs were mapped to their corresponding fourth-level Anatomical Therapeutic Chemical (ATC) codes. Then, using a hypergeometric test, for each class combination in the subset of significant drug combinations (the “inside” set), we tested for enrichment of that class combination in the inside set compared to the class combination universe, the distribution of class combinations for all unique pairwise drug-drug associations (250 unique drugs; 31,125 distinct drug combinations mapped to 1596 distinct class combinations). Multiple testing during enrichment was corrected using the BH method with a significance cutoff of p< 0.05. Results: We found 2764 pairs to be significant at a = 0.05 using the AUC measure. With a correlation coefficient of 0.77, vincristine and YK-4-279, an EWS-FLI1/RNA Helicase A inhibitor, had the lowest computed p-value of of 1.39 × 10−120 Adjusted p-values for >15% of these combinations had p-values < 5 × 10−6. Class combination enrichment on the same set showed 132 class pairs were enriched in the inside set compared to the class combination universe after BH correction. Taxanes/Plk1 inhibitors (OR = 69.5, adjusted p = 5.6 × 10−11); Aurora Kinase inhibitors/histone modifying agents (OR=9.2, adjusted p = 6.13 × 10−11); and pyrimidine analogues/CDK inhibitors (OR=3.43, adjusted p = 0.02) are a few notable enriched class combinations. The enrichment of these class combinations in the inside set suggests that combinations of drugs from these classes may be particularly effective in treating cancer compared to other drug combinations. Conclusions: Our framework, ReCorDE, demonstrates that finding potential drug combinations and characterizing novel, frequently perturbed pathways outside of a drug's primary mechanisms of action can be accomplished by identifying correlated drug-drug pairs from large, publicly accessible databases. Citation Format: Emily T. Ghose, August John, Huanyao Gao, Krishna R. Kalari, Liewei Wang. ReCorDE: A novel computational framework to discover potential combinations of anti-cancer drugs. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4290.