miR-129-2 mediates down-regulation of progesterone receptor in response to progesterone in breast cancer cells

• Published in: Cancer biology & therapy Vol. 18; no. 10; pp. 801 - 805
• Main Authors: Godbole, Mukul, Chandrani, Pratik, Gardi, Nilesh, Dhamne, Hemant, Patel, Kuldeep, Yadav, Neelima, Gupta, Sudeep, Badwe, Rajendra, Dutt, Amit
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 03-10-2017
• Subjects: Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - pathology; Brief Report; cancer genomics; Cell Line, Tumor; Chemotherapy, Adjuvant - methods; Datasets as Topic; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; hormonal therapy; Humans; microRNA; MicroRNAs - antagonists & inhibitors; MicroRNAs - metabolism; progesterone; Progesterone - pharmacology; Progesterone - therapeutic use; progesterone receptor; Progestins - pharmacology; Progestins - therapeutic use; Receptors, Progesterone - metabolism; Sequence Analysis, RNA; small RNA sequencing; hormonal therapy; progesterone; cancer genomics; microRNA; Breast cancer; progesterone receptor; small RNA sequencing
• ISSN: 1538-4047; 1555-8576
• DOI: 10.1080/15384047.2017.1373216

Objective: Hormonal therapy is an important component of first line of treatment for breast cancer. Response to hormonal therapy is influenced by the progesterone receptor (PR)-status of breast cancer patients. However as an early effect, exposure to progesterone decreases expression of PR in breast cancer cells. An understanding of the mechanism underlying down-regulation of PR could help improve response to hormonal therapy. Methods: We performed small RNA sequencing of breast cancer cells for identification of microRNAs targeting PR in response to progesterone treatment. Biochemical approaches were used to validate the findings in breast cancer cells. Results: Analysis of small RNA sequencing of four breast cancer cell lines treated with progesterone revealed an up-regulation of miR-129-2 independent of the PR status of the cells. We show that miR-129-2 targets 3′UTR of PR to down-regulate its expression. Furthermore, inhibition of miR-129-2 expression rescues the down-regulation of PR in breast cancer cells. Also, the expression levels of miR-129-2 was observed to be elevated in patients with low expression of PR in the TCGA cohort (n = 359). Conclusion: miR-129-2 mediates down-regulation of PR in breast cancer cells in response to progesterone, while anti-miR-129-2 could potentiate PR expression levels among patients with inadequate PR levels. Thus, modulation of activity of miR-129-2 could stabilize PR expression and potentially improve response to hormonal therapy under adjuvant or neo-adjuvant settings.