RESUMO
PURPOSE: The activity of mammary stem cells (MaSCs) is essential to mammary growth, differentiation and regeneration in cycles of pregnancy, lactation, and involution. The capability to recruit the mammary gland through the cycles is attributed to stem cells. It was shown that the intraductal (i.duc) injection of pegylated liposomal doxorubicin (PLD) to multiparous FVB/N mice was associated with a significantly reduced outgrowth potential of mammary gland cells. We have explored i.duc PLD's effect on stem cell number and function in mouse mammary gland and aldehyde dehydrogenase (ALDH)'s availability as a mouse MaSC marker.METHODS: The total mammary epithelium was purified from 6 to 8-month-old FVB/N control and i.duc PLD-administered mice treated twice and analyzed by flow cytometry and limiting dilution cleared mammary fat pad transplants.RESULTS: There was no significant difference in the proportions of stem cell-enriched population (CD49(fhigh)CD24(med)) between control and i.duc PLD-treated groups. However, we found a significant reduction in the outgrowth potential of CD49(fhigh)CD24(med) and CD49(fhigh)CD24(med)ALDH(+) cells from i.duc PLD-treated mammary glands. We discovered that adding ALDH to CD49(fhigh)CD24(med) had the possibility of better marker selection for MaSC of mice.CONCLUSION: We present i.duc administration of PLD to reduce MaSC function, but not the number; and ALDH activity may add further selection of MaSCs to CD49f CD24 in mouse mammary glands. Screening of chemotherapeutic drugs or other natural products by this method of stem cell analysis may provide safe i.duc treatment in breast cancer.