Experimental Treatment Efficacy of dmrFABP5 on Prostate Cancer Singly or in Combination with Drugs in Use

Enzalutamide is a drug used to treat PC. Docetaxel is a drug for chemotherapy for different cancers including prostate cancer (PC). The effectiveness of these drugs in treating castration-resistant prostate cancer (CRPC) is not consistent and thus, CRPC is still an incurable disease. Recent evidence showed that the bio-inhibitor of FABP5, dmrFABP5, suppressed the tumorigenicity and metastasis of the CRPC cells. In this work, we studied the possible synergic effect of dmrFABP5 combined with either Enzalutamide or Docetaxel on suppressing tumorigenicity of the PC cells. A highly significant synergic effect was observed when dmrFABP5 was used in combination with Enzalutamide on the androgen-responsive PC cells 22RV1. A highly significant synergic effect was also observed when dmrFABP5 was combined with Docetaxel on 22RV1 cells and on the highly malignant, androgen-receptor (AR)-negative DU145 cells. These combined applications exhibited a highly significant inhibitory action on the viability, migration, invasion and colony formation abilities of both 22RV1and DU145 cells. However, dmrFABP5 did not produce any suppression effect when used on FABP5-negative cell line LNCaP, although Enzalutamide can significantly suppress LNCaP cells as a single agent. Further investigations suggested that these synergistic effects were produced by interrupting the FABP5-related signal transduction pathway in PC cells.