Comparing the cellular distribuition of myosin VI in MCF10 and MCF7 cell lines

Myosin VI is a motor protein involved in different cellular processes. The role of myosin VI in cell migration has been linked to ovarian, prostate and breast cancer, in which myosin VI has been reported to be positively correlated with tumor grade and metastatic potential. However, its role in tumorigenesis of breast cancer and its pathological function remain unknown. This study is focused on the characterization of myosin VI and compares the protein expression and distribution using a reliable model of non-tumorigenic cell line, MCF10a cells and in parallel the tumorigenic breast cell line MCF7. Immunofluorescence and western blot analysis demonstrate overexpression of myosin VI and estrogen receptor in the tumorigenic cells MCF7. Conversely, MCF10a showed low expression of myosin VI and no expression of estrogen receptor. To investigate the role of myosin in breast cancer cells were subjected to hormone treatment where a hormone-dependent distribution for myosin VI inside the nucleus in MCF7 cells was observed. To investigate this in more detail, the endogenous expression of myosin VI and estrogen receptor were inhibited in MCF7 and in MCF10a cells using small RNA interference. Moreover, inhibition of the myosin VI ATPase was performed using the small inhibitor 2,4,6-triidrophenol (TIP). Taken together, this impacted on the cellular distribution of myosin VI. This adds support the role of myosin VI in hormone-dependent transcription with may be useful in future therapy and diagnosis.