GSE123379
NOTCH signaling is activated in and contributes to resistance in enzalutamide-resistant prostate cancer cells
Prostate cancer is the second leading cause of cancer death among men in the United States. The Androgen receptor (AR) antagonist Enzalutamide is a FDA approved therapy for treatment of late stage prostate cancer patients and is currently under clinical study for early stage prostate cancer treatment. After a short positive response period, patients will develop drug resistance. In this study we used RNA-sequencing and bioinformatics analysis to identify Notch signaling pathway as a deregulated pathway in Enzalutamide-resistant cells. NOTCH2 and c-MYC positively correlated with AR expression in patients' samples mimicking cells with Enzalutamide-resistance. In Enzalutamide-resistant cells, MR49F and C4-2R, we found that cleaved-NOTCH1, HES1 and c-MYC protein expression are significantly elevated indicating an activated NOTCH1 pathway in those cells. In addition, ADAM10 and ADAM17 had a higher expression in Enzalutamide-resistant cells, suggesting a role for S2 cleavage in the increased cleaved NOTCH1 expression. Furthermore, treatment of Enzalutamide-resistant cells with PF-03084014 in combination with Enzalutamide increased cell death, decreased colony formation ability and re-sensitized Enzalutamide-resistant cells to Enzalutamide. Knockdown of NOTCH1 in C4-2R increases Enzalutamide sensitivity by decreasing cell proliferation and increasing cell death. In a 22RV1 xenograft model, PF-03084014 and Enzalutamide induced a decrease in tumor growth through a reduced cell proliferation and increased apoptosis. These results indicate that Notch1 signaling can contribute to Enzalutamide-resistance in Prostate cancer and inhibition of this pathway can re-sensitize resistant cells to Enzalutamide. Overall design: Method: polyA selection of mRNA from enzalutamide sensitive and resistant cells (n=3 biological replicates) and sequenced on a HiSeq2500