Aspirin, when used in combination with the anticancer drug doxorubicin, can help shrink drug-resistant invasive breast tumours by inhibiting the growth of cancer stem cells, a team of cancer researchers has revealed.
Cancer stem cells, a subpopulation of tumour cells with tremendous tumour-initiating potential, contribute to the runaway growth and drug resistance of cancer cells1.
Aspirin treatment stopped the drug-resistance mechanism of the breast cancer cells, enhancing the therapeutic action of the anticancer drug, they found.
According to previous reports, aspirin has the potential to suppress the activity of cancer stem cells. To explore that potential, scientists from the Bose Institute and the Institute of Post Graduate Medical Education and Research, both in Kolkata, India, conducted experiments with specific human breast cancer cells.
They found that the scaffold/matrix associated region-binding protein 1 (SMAR1) prevents the synthesis of a major protein that helps generate drug-resistant breast cancer cells. Cancer stem cells repress SMAR1 by using two proteins, Oct4 and Sox2, that are partly responsible for the cancer cells’ unbridled growth.
Aspirin treatment suppresses the expression and levels of Oct4 and Sox4. This, in turn, restores the activity of SMAR1, silencing the action of the drug-resistant protein, the researchers found. This, they say, makes the cancer cells sensitive to doxorubicin treatment.
In mice, a combination of aspirin and doxorubicin killed breast cancer cells through apoptosis, shrinking tumour size considerably. However, aspirin alone failed to make much difference in tumour size, they report.
References
1. Bhattacharya, A. et al. SMAR1 repression by pluripotency factors and consequent chemoresistance in breast cancer stem-like cells is reversed by aspirin. Sci. Signal. 13, eaay6077 (2020)
