Breast Cancer stem cells and miRNAs

Abstract

Breast cancer remains one of the leading causes of cancer-related deaths in women. Following the initial diagnosis and treatment, a significant number of patients suffer eventual relapse characterized by chemoresistant form of the disease and poor prognosis. For this reason, there is an urgent need to discover new disease targets for successful therapy outcomes. Breast cancer stem cells (bCSCs) are a niche population that is chemoresistant, possess self-renewal capacity and contribute to malignant disease and poor clinical outcomes. In humans, bCSCs express increased levels of ALDH and cancer stem-cell marker CD44. Several studies have linked these cells to advanced breast cancer. miRNAs are small non coding RNA molecules that control gene activity via post-transcriptional regulation. There is evidence that miRNAs are involved in survival and in maintaining self-renewal capacity and chemoresistant potential of bCSCs. Thus, it may be possible to devise novel and highly effective therapy regimens that rely on identifying specific miRNAs and targeting them to prevent chemoresistance and relapse. While treatment strategies relying on replacement of antitumor miRNAs or inhibition of oncogenic miRNAs are still in their infancy, there is increasing excitement toward this RNAi approach to treat breast cancer. Many groups have started combining anti-miRNA molecular drugs with chemotherapy drugs to prevent chemoresistance. Technical and experimental strategies and advances reported here will improve the clinical outcomes for breast cancer patients.