FIGURE 5.

Buthionine sulfoximine (BSO) improves anti-PCa activities of 13. Combinatorial treatments were conducted by pretreating cells with BSO for 16 hr, followed by drugs (13, 11b or PEITC-NAC) for 24 hr at indicated concentrations. Viability was measured using MTT assay (n = 6–8) in a, c, and d, data reflect mean ± SD. (a) 13 (1–5 μM) plus BSO (2.5–10 μM) synergistically reduced viability of VCaP cells and 22Rv-1 cells. (b) 13 (1 μM in 22Rv1; 2.5 μM in C4–2) plus BSO (5 μM) combination effectively inhibits colony formation of C4–2 and 22Rv1 cells (1,000 cell/well). Cells were treated for 24 hr and then were grown in drug-free media. (c) Non-cancerous RWPE-1 cells are much less affected by drug combination. (d) 13 is a better “carrier” of ITC. (e) 13 plus BSO effectively downregulates AR or AR-V7 and upregulates HO-1 and Hsp70. VCaP or 22Rv-1 cells were pretreated with BSO (100 μM) for 6 hr followed by 13 (2.5 μM) co-treatment for 16 hr. Indicated proteins and GAPDH (loading control) were analyzed using Western blotting. Representative images are shown. P-NAC, PEITC-NAC