Figure 4.

CTGF overexpression confers resistance to TMZ. Western blot analysis of CTGF expression in U87 and U251 cells transfected with CTGF or Vector Control (VC), respectively. β-actin served as the loading control (a). Colony forming ability of U87 and U251 CTGF overexpressing or VC cells in the absence or presence of TMZ by Giemsa staining, *P<0.05 compared to non-treated VC cells, ^&P<0.05 compared to TMZ-treated VC cells (b). Cell viability of U87 and U251 CTGF or VC cells treated with different TMZ concentrations for 24 h and determined by CCK-8 assay. Data were showed as the percentage of cells treated without TMZ (c). U87 and U251 CTGF or VC cells were exposed to 500 μM TMZ for 48 h and the apoptosis was measured by Hoechst 33342 staining (d) and cleaved PARP protein expression (e), *P<0.05 compared to VC cells treated without TMZ, ^&P<0.05 compared to VC cells with TMZ treatment. Growth curve of U87 CTGF or VC cells-derived subcutaneous tumor xenografts after treatment with TMZ, *P<0.05 compared to VC cells-derived tumor xenograft (f). Representative images of tumors originated from U87 CTGF or VC cells on day 35 and mean of tumor weight, *P<0.05 (g). Immunohistochemistry and relative cleaved PARP expression analysis in U87 CTGF or VC cells-derived tumor xenograft, scale bar=200 μm, *P<0.05 (h). Western blot analysis of MDR1, MRP1, BCRP1, MGMT protein expressions in U87 CTGF or VC cells-derived tumor xenograft (i). Results above are expressed as the mean±S.D. of three independent experiments