Transmembrane 7 superfamily member 4 regulates cell cycle progression in breast cancer cells

TM7SF4 (transmembrane 7 superfamily member 4) gene encodes a seven-pass transmembrane protein that is primarily expressed in dendritic cells called as dendritic cell-specific expressed seven transmembrane protein (DC-STAMP). This protein regulates immunological functions, osteoclastogenesis and myeloid differentiation. Although the roles of TM7SF4 have been currently studied on Paget's disease of bone and papillary thyroid cancers, it is unclear whether TM7SF4 plays a role in breast cancer. In current study, we investigated the expression of TM7SF4 in human breast cancer cell lines.

In this study, five breast cancer lines were cultured. Small hairpin RNA against TM7SF4 using a lentiviral vector was generated and transfected into MCF-7 breast cancer cells. Effects of down-regulating TM7SF4 in transfected cells were examined by Western blot, RT-PCR, apoptotic rate, colony formation, and cell cycle analyses.

The results demonstrated that down-regulation of TM7SF4 led to a decrease in colony formation in MCF-7 cells compared to the control group. This is likely due to a decrease in proliferation and cell cycle and an increase in apoptosis.

To our knowledge, our data demonstrate for the first time that TM7SF4 plays an essential role in regulating cell cycle progression in breast cancer.