Cooperative role of BRAF V600E and TERT in the oncogenic behavior and tumor growth of cancer cells. Specific shRNA against BRAF and siRNA against TERT were used to knock down BRAF and TERT in the indicated cancer cells, respectively, followed by performance of assays of MTT of cell proliferation (a), transwell cell migration (b), cell invasion (c), and colony formation in soft agar (d) (with representative images shown in the left panel and the average colony numbers in the right panel). Western blotting analysis of TERT and phosphorylation of ERK (p-ERK) was performed for K1 cells (e), from which xenograft tumors were derived to test the role of TERT and BRAF V600E in tumor development and growth (f, g). Panel f shows the time course of tumor growth and panel g shows the weights of tumors surgically excised. The “Control” in a−d represented the combination of scramble shRNA and Control siRNA. The “Control” in e−g represented the combination of scramble shRNA and DMSO. The horizontal bar in panels b and c represents 100 μm. The red horizontal bar on the left of panel d represents 100 μm; colonies larger than this size were counted and colony numbers are shown on the right of the panel. Little vertical bars in a, d, f, and g represent standard deviation (SD). *P < 0.05, **P < 0.01, ***P < 0.001, by two-tailed Student’s t test. In panel a, the P values are for the comparison of the indicated condition with “BRAF/TERT knockdown (KD)” (red line). In panel f, the P values are for the comparison of the indicated condition with “PLX4032/shTERT” (red line)