Advertisement
You are prohibited from using or uploading content you accessed through this website into external applications, bots, software, or websites, including those using artificial intelligence technologies and infrastructure, including deep learning, machine learning and large language models and generative AI.

INTRODUCTION AND OBJECTIVES

Prostate cancer remains the second-leading cause of cancer-related deaths in American men with an estimated mortality of nearly 28,000 in 2015 alone. The advent of more potent therapeutics in the recent years has resulted in an increase in the number cases of a rare, aggressive and highly treatment-resistant variant of the disease called neuroendocrine prostate cancer (NEPC), presumably as a means of resistance development. Understanding the mechanism of the NE trans-differentiation process has been hampered due to the poor availability of a universal model system, and is crucial towards determining alternative therapy regimens. Here, we show that treatment of PCa cells with Dovitinib (TKI-258/CHIR-258), a pan receptor tyrosine kinase (RTK) inhibitor induces NE differentiation, both in vitro and in vivo, opening up the possibility of studying the signaling pathways driving NE differentiation.

METHODS

Cell lines (PC3, LNCaP, DU145 and CW22Rv1) were cultured in RPMI1640 supplemented with 10% fetal bovine serum (FBS). Cell viability was measured using the WST assay (Clontech). Fluorescence microscopy and Western blotting for neuroendocrine markers was performed on cells treated with Dovitinib for 3 weeks. Q-PCR was performed on total RNA isolated from Dovitinib treated cells. Nude mice with xenografted tumors were treated with Dovitinib and tumors analyzed through Western blotting and immunohistochemistry.

RESULTS

Dovitinib treated LNCaP and PC3 cells showed neurite formation, a characteristic of NE differentiation. This was associated with the expression of NE markers such as neuron specific enolase (NSE), synaptophysin and chromogranin, both at the RNA and protein level. We validated the findings in additional AR +ve cell line (CWR22Rv1) and AR -ve cell line (DU145). Xenografted PC3 tumors in nude mice also showed NE differentiation when mice were treated with Dovitinib. The exact mechanistic underpinnings of this NE differentiation are unclear, but seem to be supported through MAPK and PI3K signaling pathways.

CONCLUSIONS

Our study for the first time demonstrates that Dovitinib can induce neuroendocrine in AR +ve and AR –ve PCa cell lines, both in vitro and in vivo. It provides a robust tool to study the NE differentiation process in vitro and identify vulnerabilities for therapeutic intervention. The NE differentiation might be a potential mechanism of resistance development to Dovitinib therapy, and thus could have critical clinical implications.

Advertisement