RESUMO
BACKGROUND: A preoperative-progesterone intervention increases disease-free survival in patients with breast cancer, with an unknown underlying mechanism. We elucidated the role of non-coding RNAs in response to progesterone in human breast cancer. METHODS: Whole transcriptome sequencing dataset of 30 breast primary tumors (10 tumors exposed to hydroxyprogesterone and 20 tumors as control) were re-analyzed to identify differentially expressed non-coding RNAs followed by real-time PCR analyses to validate the expression of candidates. Functional analyses were performed by genetic knockdown, biochemical, and cell-based assays. RESULTS: We identified a significant downregulation in the expression of a long non-coding RNA, Down syndrome cell adhesion molecule antisense DSCAM-AS1, in response to progesterone treatment in breast cancer. The progesterone-induced expression of DSCAM-AS1 could be effectively blocked by the knockdown of progesterone receptor (PR) or treatment of cells with mifepristone (PR-antagonist). We further show that knockdown of DSCAM-AS1 mimics the effect of progesterone in impeding cell migration and invasion in PR-positive breast cancer cells, while its overexpression shows an opposite effect. Additionally, DSCAM-AS1 sponges the activity of miR-130a that regulates the expression of ESR1 by binding to its 3'-UTR to mediate the effect of progesterone in breast cancer cells. Consistent with our findings, TCGA analysis suggests that high levels of miR-130a correlate with a tendency toward better overall survival in patients with breast cancer. CONCLUSION: This study presents a mechanism involving the DSCAM-AS1/miR-130a/ESR1 genomic axis through which progesterone impedes breast cancer cell invasion and migration. The findings highlight the utility of progesterone treatment in impeding metastasis and improving survival outcomes in patients with breast cancer.
Assuntos
Neoplasias da Mama , MicroRNAs , RNA Longo não Codificante , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , MicroRNAs/genética , Progesterona/farmacologia , Proliferação de Células/genética , Linhagem Celular Tumoral , Movimento Celular/genética , RNA Longo não Codificante/genética , Regulação Neoplásica da Expressão GênicaRESUMO
Preoperative progesterone intervention has been shown to confer a survival benefit to breast cancer patients independently of their progesterone receptor (PR) status. This observation raises the question how progesterone affects the outcome of PR-negative cancer. Here, using microarray and RNA-Seq-based gene expression profiling and ChIP-Seq analyses of breast cancer cells, we observed that the serum- and glucocorticoid-regulated kinase gene (SGK1) and the tumor metastasis-suppressor gene N-Myc downstream regulated gene 1 (NDRG1) are up-regulated and that the microRNAs miR-29a and miR-101-1 targeting the 3'-UTR of SGK1 are down-regulated in response to progesterone. We further demonstrate a dual-phase transcriptional and post-transcriptional regulation of SGK1 in response to progesterone, leading to an up-regulation of NDRG1 that is mediated by a set of genes regulated by the transcription factor AP-1. We found that NDRG1, in turn, inactivates a set of kinases, impeding the invasion and migration of breast cancer cells. In summary, we propose a model for the mode of action of progesterone in breast cancer. This model helps decipher the molecular basis of observations in a randomized clinical trial of the effect of progesterone on breast cancer and has therefore the potential to improve the prognosis of breast cancer patients receiving preoperative progesterone treatment.
Assuntos
Neoplasias da Mama/patologia , Proteínas de Ciclo Celular/metabolismo , Proteínas Imediatamente Precoces/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Progesterona/farmacologia , Proteínas Serina-Treonina Quinases/genética , Receptores de Progesterona/metabolismo , Fator de Transcrição AP-1/metabolismo , Regulação para Cima/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Receptores ErbB/metabolismo , Humanos , Proteínas Imediatamente Precoces/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Invasividade Neoplásica , Proteínas Serina-Treonina Quinases/metabolismoRESUMO
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.