Targeting cancer cells from the outside

New research suggests that cancer treatments can target proteins outside cancer cells in the future, rather than inside.

During cancer chemotherapy, drugs attack the cancer cells and either kill them off or move them to a state in which they can no longer proliferate, known as senescence. This state is not fully understood but scientists at the University of Texas Health Science Center at San Antonio have shed more light in a new study published in Proceedings of the National Academy of Sciences.

The team treated cultured breast cancer cells with the conventional cancer drug doxorubicin and used a proteomics approach to identify proteins that are released from the cells under stress. They found that one particular protein, insulin-like growth factor binding protein 3 (IGFBP3), is released by the cells to stop proliferation, effectively inducing senescence. "This raised a possibility that IGFBP3 suppresses tumors by inducing senescence in preneoplastic cells," they say. "By spreading senescence to tumor cells that escaped the direct impact of chemotherapy, IGFBP3 may improve the treatment efficacy and prognosis."

Lead author Yuzuru Shiio highlighted the importance of this discovery. "Because this protein cascade is outside the cells, it is likely amenable to therapeutic manipulation. I hope our study will ultimately lead to a therapeutic strategy to reprogram cancer cells to a state of permanent dormancy.”

Although the results are promising, Shiio reminds us that this work was conducted with cell cultures and it takes a long time to transfer from this stage to a new and effective cancer treatment.