Downregulation of long non-coding RNA MALAT1 induces tumor progression of human breast cancer through regulating CCND1 expression

Abstract

ObjectiveMetastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is already known to be involved in the development and progression of many types of tumors. In the present study, we set to seek the role of MALAT1and the molecular mechanisms in breast cancer.MethodsMALAT1 mRNA expression level was measured by real-time PCR in selected tissues and breast cancer cell lines. SiRNAs targeting MALAT1 were employed to knockdown the endogenous MALAT1. Then cell counting method and colony formation method were applied to reveal the proliferation changes after MALAT1 was suppressed. Afterwards, the mRNA and protein expression of growth related gene cyclinD1 (CCND1) were detected by RT-PCR and western blotting, respectively.ResultsWe found a downregulation of MALAT1 expression in breast cancer cell lines and tissues. Inhibition of its expression led to enhanced cell proliferation and colony formation. Importantly, the mRNA and protein expression of CCND1 was significantly increased in MALAT1-depleted cells.ConclusionMALAT1 is a potential tumor suppressive long non-coding RNA that negatively regulates cell proliferation in breast cancer progression, via suppressing CCND1 expression.

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