[Derepression of CXCR7 indicates resistance to enzalutamide in castration resistant prostate cancer]

Abstract

Objective: To investigate the effect of the derepression of chemokine receptor-7 (CXCR7) in prostatic tissues from patients with Castration Resistant Prostate Cancer (CRPC) on the resistance to enzalutamide (Enza). Methods: During the period of January 2015 to December 2017 all CRPC cases who underwent radical radiotherapy or androgen deprivation therapy (ADT) were evaluated. After prostatic puncture biopsy, the tissues were treated for immunostaining with CXCR7. Cox proportional hazard modeling and Kaplan-Meier analysis were used to determine PSA Progression-Free Survival (PSAP-FS) and Clinical or Radiographic Progression-Free Survival (CRP-FS) in the cohort. At last, PSA response rates and progression outcomes in CXCR7 negative cases and CXCR7 positive cases were analyzed. Results: Total 39 CRPC patients were enrolled in this study. And 23 cases derepress CXCR7, 16 cases negatively express CXCR7. The median follow-up duration was 12 months (range: 6-18) in the cohort. Chi-square analysis confirmed that PSA response rates after Enza treatment were significantly associated with CXCR7 derepression (χ(2)=22.129, P=0.000 06). Compared with CXCR7 positive expression group, CXCR7 negative expression group displayed improved median PSAP-FS (4.4 mon vs 11.7 mon, P=0.040 8) and CRP-FS (5.2 mon vs 13.1 mon, P=0.036 2) after Enza treatment. Conclusion: Derepression of CXCR7 in CRPC patients may be associated with resistance to enzalutamide. This protein may be novel target for treatment of CRPC.

Keywords: CXCR7; Castration Resistant Prostate Cancer; Enzalutamide; Resistance.