Figure 6.

Effect of TM treatment on BRAF inhibitor resistant cells. (a) Melanoma and colon cancer cell lines show different sensitivity to PLX4720 treatment. Melanoma cell line A375 (BRAF^V600E), colon cancer HCT-116 (BRAF^wt) and HT-29 (BRAF^V600E) were treated with the increasing doses of PLX4720. After 48 hours of treatment, cell survival was quantified using the WST-1 cell proliferation assay kit. (b) Combination therapy of PLX4720 and TM affects BRAF^V600E colon cancer cell proliferation. HCT-116 (BRAF^wt) and HT-29 (BRAF^V600E) were treated with PLX4720 1 µM or TM 10 µM alone or in combination. After 24 hours of treatment, cell survival was quantified using the WST-1 cell proliferation assay kit. c) TM treatment affects clonogenic ability of BRAF mutant colon cancer cells resistant to PLX4720. PLX4720-resistant colon cancer HT-29 cells were established by continuous exposure to step-wise increasing concentrations of PLX4720, from 0.1 µM to 4 µM, until the surviving cells reached 90% confluence. Response to combination treatment with PLX4720 and TM was evaluated by clonogenic assay in HT-29-PLX4720- resistant cells. The medium was changed every 3–4 days and after 10 days grown colonies were stained with crystal violet (c) and quantified by densitometric analysis (d). Results are reported as means ± standard deviation of three independent experiments. * p < 0.05.