Figure 4. XRK3F2 blocks MM cell growth.

A. Effect of XRK3F2 on human MM cell lines and the murine 5TGM1 cell line. Each cell line was treated with 10µM XRK3F2 and analyzed by MTT assay. Data are shown as the mean ± SD (n=5). *p<0.01 compared to cell cultures treated with vehicle. B. XRK3F2 blocks primary MM cell growth. CD138⁺ cells from MM patients were treated with 10µM of XRK3F2 for 48 hours and analyzed for cell viability by MTT assay. Data are shown as the mean ± SD (n=5). *p<0.01 compared to vehicle treated cultures. C. The IC₅₀ for PY1-32 against 5TGM1-gfp murine multiple myeloma cells in a 72 hour MTT assay was 4.35 µM. D. XRK3F2 induced cleavage of caspase 9, 7 and 3 in MM1.S cells. MM1.S cells were cultured with 10µM XRK3F2 for the indicated time and cell lysates were collected. Cleaved and uncleaved caspases 9, 7 and 3 were detected by Western blotting using anti-cleaved and uncleaved caspase 9, 7 and 3 specific antibodies.