Lentivirus-Mediated Silencing of Myosin VI Inhibits Proliferation and Cell Cycle Progression in Human Lung Cancer Cells.

Myosin VI (MYO6) is a unique actin motor, which moves toward the pointed ends of actin filaments. In this study, we found that MYO6 is overexpressed in lung cancer tissues and associated with lung cancer progression, particularly lymph node metastasis. To investigate its functions in lung cancer cells, we generated recombinant lentivirus taking shRNA of MYO6. Using two lung cancer cell lines, A549 and 95D, we found that Lv-shMYO6 could infect lung cancer cells with high efficiency and downregulate MYO6 on both mRNA and protein levels. After knockdown of MYO6, the proliferation rates of lung cancer cells were decreased significantly. The colony-formation ability of MYO6-silenced lung cancer cells was also impaired with reduced colony numbers and fewer cells per colony. Flow cytometry showed that cell cycle progression was stuck at the G0 /G1 phase, especially at the sub-G1 phase, which represents apoptotic cells. Moreover, knockdown of MYO6 downregulated the phosphorylation of ERK1/2. Further experiments using another shRNA of MYO6 confirmed the above results. These results suggest that MYO6 is crucial in maintaining cell cycle and cell growth of lung cancer cells. MYO6 may serve as a potential therapeutic target for lung cancer treatment.