Abstract C100: Defining the role of Hedgehog, Notch, and Wnt signaling pathways in aggressive lethal prostate cancer of Hispanic men

Abstract Background: Hispanic American (HA) men with prostate cancer (PC) are more likely to have more aggressive and advanced diseases and greater mortality rates compared to non-Hispanic white (NHW) men. Resistance to the current anticancer therapy is the major hurdle that leads to poor clinical outcomes. Hedgehog, Notch, and Wnt signaling pathways play a crucial role in development, progression, and resistance to the various anticancer therapies. Here, we characterized the enrichment of Hedgehog, Notch, and Wnt signaling pathways and molecular tumors differences between HA and NHW patients. Methods: Our data consist of 88 PC tumors samples (HA=34, NHW=54) obtained from treatment-naive metastatic hormone-sensitive prostate cancer (mHSPC) that were analyzed by next-generation sequencing (592, NextSeq; Whole Exome Sequencing, NovaSeq) and Whole Transcriptome Sequencing (WTS; NovaSeq) (Caris Life Sciences, Phoenix, AZ). Pathway enrichment was determined by Gene Set Enrichment Analysis (GSEA, Broad Institute) by measurable TPM (transcripts per kilobase million). The medical records were reviewed in a deidentified fashion for clinical features. Statistical significance was determined using chi-square and Mann-Whitney U (p0.05). Results: HA PC had enrichment of Hedgehog signaling (NES: 1.45, FDR=0.04), Notch signaling (NES: 1.41, FDR=0.07), and Wnt/β-catenin signaling (NES: 1.38, FDR=0.11) pathways compared to NHW tumors. HA tumors had higher expression of genes (HES1, Notch1, WNT1, WNT2; FC:1.1-2.5) associated with crosstalk between Hedgehog, Notch, and Wnt/β- catenin signaling pathways (all p0.05). Moreover, HA tumors had higher expression of stemness (ALDH1A2, ALDH1A1, PROM1; FC: 1.7-3.0), drug efflux (ABCC1, ABCB1; FC: 1.1- 1.5), epithelial to mesenchymal transition (EMT) (TWIST1, MMP2; FC: 1.1-1.5), cell cycle (CCND2; FC: 1.2), inhibition of apoptosis (BIRC2, XIAP; FC: 1.1) and epigenetic (EP300, TET1, TET2; FC: 1.3-1.4) related genes compared to NHW tumors (all p0.05). HA PC had higher frequency of Hedgehog and Wnt/β-catenin associated SPOP (16% vs 6.6%, p=0.2) and CTNNB1 (12% vs 2.2%, p=0.1) mutation compared to NHW PC. Conclusion: These results demonstrate that tumors from HA patients had enrichment of oncogenic Hedgehog, Notch, and Wnt/β-catenin signaling pathways, higher expression of stemness, drug efflux, EMT, cell cycle, inhibition of apoptosis and epigenetic-related genes, and mutations directly involved in activating the Hedgehog and Wnt/β-catenin signaling pathways. Together, these findings suggest that tumors from HA patients are enriched for gene signatures that promote cancer progression and therapy resistance. Additional research on collaboration and crosstalk between Hedgehog, Notch, and Wnt/β-catenin signaling pathways may help in designing better therapeutic strategies for HA men with mHSPC. Citation Format: Alejandro Recio-Boiles, Sachin Kumar Deshmukh, Ricardo J. Estrada-Mendizabal, Kenneth Barker, Sharon Wu, Joanne Xiu, Milan Radovich, Elisabeth I. Heath, Rana McKay, Juan Chipollini, Cynthia K. Miranti. Defining the role of Hedgehog, Notch, and Wnt signaling pathways in aggressive lethal prostate cancer of Hispanic men abstract. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C100.