Histone deacetylase 1/Sp1/microRNA-200b signaling accounts for maintenance of cancer stem-like cells in human lung adenocarcinoma.

Dong-Qin Chen,Wei De,Bing Feng,Long-Bang Chen,Rui Wang,Jia-Yuan Huang,Ban-Zhou Pan,Jin Q Cheng

doi:10.1371/journal.pone.0109578

Abstract

The presence of cancer stem-like cells (CSCs) is one of the mechanisms responsible for chemoresistance that has been a major hindrance towards lung adenocarcinoma (LAD) treatment. Recently, we have identified microRNA (miR)-200b as a key regulator of chemoresistance in human docetaxel-resistant LAD cells. However, whether miR-200b has effects on regulating CSCs remains largely unclear and needs to be further elucidated. Here, we showed that miR-200b was significantly downregulated in CD133+/CD326+ cells that exhibited properties of CSCs derived from docetaxel-resistant LAD cells. Also, restoration of miR-200b could inhibit maintenance and reverse chemoresistance of CSCs. Furthermore, suppressor of zeste-12 (Suz-12) was identified as a direct and functional target of miR-200b, and silencing of Suz-12 phenocopied the effects of miR-200b on CSCs. Additionally, overexpression of histone deacetylase (HDAC) 1 was identified as a pivotal mechanism responsible for miR-200b repression in CSCs through a specificity protein (Sp) 1-dependent mechanism, and restoration of miR-200b by HDAC1 repression significantly suppressed CSCs formation and reversed chemoresistance of CSCs by regulating Suz-12-E-cadherin signaling. Also, downregulation of HDAC1 or upregulation of miR-200b reduced the in vivo tumorigenicity of CSCs. Finally, Suz-12 was inversely correlated with miR-200b, positively correlated with HDAC1 and up-regulated in docetaxel-resistant LAD tissues compared with docetaxel-sensitive tissues. Taken together, the HDAC1/miR-200b/Suz-12-E-cadherin signaling might account for maintenance of CSCs and formation of chemoresistant phenotype in docetaxel-resistant LAD cells.

Highlights

Lung cancer accounts for the most cancer-related mortalities in both women and men worldwide [1]
CD133+/CD326+ cells exhibit properties of Cancer stem-like cells (CSCs) To better understand the underlying mechanisms responsible for chemoresistance in lung adenocarcinoma (LAD), CD133+/CD326+ cells were sorted from the docetaxel-resistant LAD cells by CD133 and CD326 MicroBeads
We analyzed the mammosphere forming mediated by miR-200b upregulation, while silencing of suppressor of zeste12 (Suz-12) rescued the decreased expression of mRNA and protein of E-cadherin in CSCs (SPC-A1/ DTX) induced by miR-200b repression. (F) quantitative reverse-transcription polymerase chain reaction (qRT-PCR) detection of miR-200b and Suz-12 mRNA expression at the indicated time after plating CD133+/ CD326+ CSCs under differentiation conditions. (G1, G2) The protein levels of Suz-12 and E-cadherin at the indicated time after cultivating CD133+/ CD326+ CSCs under differentiation conditions. (H) MiR-200b upregulation decreased the amount of Suz-12 binding to the promoter of E-cadherin in

Summary

Introduction

Lung cancer accounts for the most cancer-related mortalities in both women and men worldwide [1]. It has been firmly established that CSCs are linked to epithelialmesenchymal transition (EMT), metastasis, drug resistance, progression and relapse of lung cancer [11,12,13,14,15]. Exploitation of the specific therapies targeting at CSCs has been a crucial issue in chemotherapeutic treatment of lung cancer. MicroRNAs (miRNAs) silence gene expression by binding to the 39-untranslated region of the target genes and have been reported to regulate CSCs self-renewal, tumorigenicity, metastasis, and chemoresistance in many human cancers [2,7,16]. MiR-21 regulates EMT phenotype and hypoxia-inducible factor-1a expression in third-sphere forming breast cancer stem cell-like cells. Whether miR-200b regulates CSCs derived from docetaxel-resistant LAD cells is still poorly understood and needs to be further elucidated

Methods

Results

Conclusion