MiR-1254 suppresses HO-1 expression through seed region-dependent silencing and non-seed interaction with TFAP2A transcript to attenuate NSCLC growth.

Mengfan Pu,Chenggang Li,Jing Chen,Lingling Miao,Jin Ren,Xinming Qi,Lulu Gao,Yizheng Wang,Ronald B Gartenhaus

doi:10.1371/journal.pgen.1006896

Abstract

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which direct post-transcriptional gene silencing (PTGS) and function in a vast range of biological events including cancer development. Most miRNAs pair to the target sites through seed region near the 5’ end, leading to mRNA cleavage and/or translation repression. Here, we demonstrated a miRNA-induced dual regulation of heme oxygenase-1 (HO-1) via seed region and non-seed region, consequently inhibited tumor growth of NSCLC. We identified miR-1254 as a negative regulator inhibiting HO-1 translation by directly targeting HO-1 3’UTR via its seed region, and suppressing HO-1 transcription via non-seed region-dependent inhibition of transcriptional factor AP-2 alpha (TFAP2A), a transcriptional activator of HO-1. MiR-1254 induced cell apoptosis and cell cycle arrest in human non-small cell lung carcinoma (NSCLC) cells by inhibiting the expression of HO-1, consequently suppressed NSCLC cell growth. Consistently with the in vitro studies, mouse xenograft studies validated that miR-1254 suppressed NSCLC tumor growth in vivo. Moreover, we found that HO-1 expression was inversely correlated with miR-1254 level in human NSCLC tumor samples and cell lines. Overall, these findings identify the dual inhibition of HO-1 by miR-1254 as a novel functional mechanism of miRNA, which results in a more effective inhibition of oncogenic mRNA, and leads to a tumor suppressive effect.

Highlights

MicroRNAs are a class of small non-coding RNAs, which direct post-transcriptional gene silencing (PTGS) and play important regulatory roles in a vast range of cellular processes including cell differentiation, proliferation, apoptosis, and migration [1,2,3]
It is generally accepted that miRNAs bind to 3‘UTR of target mRNAs and direct posttranscriptional gene silencing (PTGS) via its seed sequence
We described that miR-1254 repressed heme oxygenase-1 (HO-1) at posttranscriptional level by directly targeting HO-1 3’UTR via its seed sequence and inhibited HO-1 transcription by suppressing the transcriptional factor AP-2 alpha

Summary

Introduction

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which direct post-transcriptional gene silencing (PTGS) and play important regulatory roles in a vast range of cellular processes including cell differentiation, proliferation, apoptosis, and migration [1,2,3]. For a majority of miRNAs, as few as 6nt of the seed sequence matching with the target mRNA is required for functional interaction. Imperfect matches of miRNA seed region with the target can be compensated by supplemental components in near-perfect sites and function in target cleavage [12, 14,15,16]. Subsequent study demonstrated that 11-mer matches of miRNA “centered sites” to the target mRNA with single mismatches or GU wobbles form hybrids but only a small proportion leads to a repression [20], which indicates additional mechanism besides sequence complementarity may be necessary

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Discussion

Conclusion