Investigation of L-carnitine effects on CD44(+) cancer stem cells from MDA-MB-231 breast cancer cell line as anti-cancer therapy

Breast cancer stem cells (BCSCs) are a small subpopulation of breast cancer cells, capable of metastasis, recurrence, and drug resistance in breast cancer patients. Therefore, targeting BCSCs appears to be a promising strategy for the treatment and prevention of breast cancer metastasis. Mounting evidence supports the fact that carnitine, a potent antioxidant, modulates various mechanisms by enhancing cellular respiration, inducing apoptosis, and reducing proliferation and inflammatory responses in tumor cells. The objective of this study was to investigate the impact of L-carnitine (LC) on the rate of proliferation and induction of apoptosis in CD44(+) CSCs. To achieve this, the CD44(+) cells were enriched using the Magnetic-activated cell sorting (MACS) isolation method, followed by treatment with LC at various concentrations. Flow cytometry analysis was used to determine cell apoptosis and proliferation, and western blotting was performed to detect the expression levels of proteins. Treatment with LC resulted in a significant decrease in the levels of p-JAK2, p-STAT3, Leptin receptor, and components of the leptin pathway. Moreover, CD44(+) CSCs-treated cells with LC exhibited a reduction in the proliferation rate, accompanied by an increase in the percentage of apoptotic cells. Hence, it was concluded that LC could potentially influence the proliferation and apoptosis of CD44(+) CSC by modulating the expression levels of specific protein.