All cells in the body go through the cell-cycle, a series of checkpoints which must be passed for a cell to survive and be allowed to divide. Healthy cells express PD-L1 which binds to PD-1 on an immune cell, telling the immune cell to let it survive. Cells which do not have PD-L1 on their surface are seen as unhealthy and so are safely removed by the immune system.
Tricking the immune system
Some cancers are able to produce their own PD-L1, thus tricking the immune system into not killing the cancer cell. By blocking the interaction between a cancer's PD-1 and PD-L1 with anti-PD-L1 drugs, we can allow the immune system to recognise and remove the cancer cells.
Breast cancer is not traditionally thought of as being a cancer with a lot of immune cell involvement, but some of our recent research suggests the immune cell presence is important. The Dunbier Lab are investigating how breast cancer cells can product their own PD-L1 by creating cells that over-express PD-L1. We can look into which other genes are affected, and hopefully this will inform us about the regulation and control of PD-L1.
Alongside this research, we are also investigating the expression of PD-L1 in a breast cancer mouse model and testing if the anti-PD-L1 drugs will work well with breast cancer drugs, such as Tamoxifen, which are currently prescribed for treatment.