Background: Almost all metastatic hormone-sensitive prostate cancers (mHSPC) will develop into metastatic castration-resistant prostate cancer (mCRPC) after androgen deprivation therapy (ADT). The expression level of squalene monooxygenase (SQLE) is increased in CRPC cells and regulates cholesterol metabolism. This study verified the biological function and mechanisms of SQLE in CRPC.
Methods: The expression of SQLE in human prostate cancer cells was overexpressed or silenced and its efficacy on cell survival was determined by the MTS test. Energy metabolism phenotype test was evaluated by XF real-time ATP rate assay, XF cell mitochondrial stress test, XF glycolysis stress test and XF mito fuel flex test. Cell migration and invasion were evaluated by colony formation assays and transwell assays; the expression of mRNA and protein was assessed by RT-qPCR and Western blot, respectively. Moreover, BALB/c nude mice model was performed to evaluate the lymph node metastasis.
Results: In our study, we found that the expression level of SQLE was significantly increased in bicalutamide-resistant-C4-2B cells compared to LNCaP cells. SQLE knockdown partly restored the sensitivity of drug-resistant cells to bicalutamide and reduced lymph node metastasis by inhibiting fatty acid oxidation in mitochondria. We also found that terbinafine, the specific inhibitor of SQLE, can enhance the sensitivity of prostate cancer cells to bicalutamide.
Conclusion: Our study revealed that SQLE is involved in the progression of castration resistance in CRPC through mediating metabolic reprogramming, presenting SQLE as a new target for the treatment of mCRPC.
Keywords: SQLE, bicalutamide, CRPC, ADT, lymph node metastasis