Figure 7.

6BIO Produces Potent Suppression of AR and AR-V7 Expression in Prostate Cancer Cells Compared with Other GSK-3 Inhibitors

(A) Flow cytometric data analysis of EGFP expression in HeLa-EGFP-654 cells treated with 10 μM CHIR and 2 μM 6BIO with or without SSO for 2 days. The profiles shown are typical of several independent experiments. (B) RT-PCR analysis of RNA harvested from LNCaP cells treated with 1 μM CHIR or 1 μM 6BIO for 24 hr. CHIR represses AR and PSA expression in LNCaP cells, although not to the same extent as 6BIO. Untreated cells (Con) served as the control for these experiments. Values were normalized to β-actin mRNA expression and expressed as the mean ± SD. n = 3. *p < 0.05, ***p < 0.001, Student’s t test. Representative western blot of (C) LNCaP and (D) 22Rv1 cells, treated with the indicated concentrations of 6BIO, CHIR, or lithium chloride (LiCl) for 3 days. In LNCaP cells, a minimum of 5 μM CHIR is required to achieve a comparable AR suppression as 1 μM 6BIO. In 22RV1 cells, 10 μM CHIR is required to achieve the same full AR suppression as 4 μM 6BIO. LiCl treatment of both LNCaP and 22RV1 cells showed little effect on AR downregulation at up to a 1 mM concentration. GAPDH was used as the standard control. The experiments were repeated two times with similar results.