Figure 6

MMP-10 regulates HeLa xenograft tumorigenicity. A, Human and mouse MMP-10 expression in subcutaneous HeLa tumors and in parental HeLa cells grown in culture was assessed by qPCR. Gene expression level was normalized to GAPDH. Cultured parental HeLa cells expressed minimal MMP-10, but when grown in a subcutaneous mouse model, increases in both human and mouse MMP-10 were noted. B, Tumor growth was established by subcutaneous injection of parental HeLa cells into athymic nude mice (nu/nu). PBS (negative control), scrambled siRNA (negative control), human MMP-10 siRNA and murine MMP-10 siRNA reagents were injected intratumorally twice weekly as described in Materials and Methods. Tumor size was plotted as mean ± SD from the four treatment groups (n = 10/group). Treatment with siRNA MMP-10 human alone, siRNA MMP-10 mouse alone and the combination of human and mouse siRNA MMP-10 were associated with a significant reduction in tumor burden. *, p < 0.05. C, Human MMP-10 and mouse MMP-10 expression in excised tumors are shown (images 400 ×, Bar = 50 μm). A reduction in MMP-10 and CD31 expression along with an induction of cleaved caspase-3 was noted in tumors treated with human MMP-10 siRNA alone, mouse MMP-10 siRNA alone and the combination of human and mouse siRNAs. D, MMP-10 expression was quantified based on MMP-10 staining. E, Microvessel density (MVD) was quantified based on CD31 staining. Apoptotic index (AI) was quantified based on cleaved caspase-3 staining. Data are presented as mean ± SD, *, p < 0.05 compared to negative control.