Down-regulation of nicotinamide N-methyltransferase induces apoptosis in human breast cancer cells via the mitochondria-mediated pathway

Jun Zhang; Yanzhong Wang; Guiling Li; Haitao Yu; Xinyou Xie

doi:10.1371/journal.pone.0089202

Down-regulation of nicotinamide N-methyltransferase induces apoptosis in human breast cancer cells via the mitochondria-mediated pathway

PLoS One. 2014 Feb 18;9(2):e89202. doi: 10.1371/journal.pone.0089202. eCollection 2014.

Authors

Jun Zhang¹, Yanzhong Wang¹, Guiling Li¹, Haitao Yu¹, Xinyou Xie²

Affiliations

¹ Clinical Laboratory, Sir RunRun Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
² Clinical Laboratory, Sir RunRun Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China ; Key Laboratory of Biotherapy of Zhejiang Province, Hangzhou, China.

Abstract

Nicotinamide N-methyltransferase (NNMT) has been found involved in cell proliferation of several malignancies. However, the functional role of NNMT in breast cancer has not been elucidated. In the present study, we showed that NNMT was selectively expressed in some breast cancer cell lines, down-regulation of NNMT expression in Bcap-37 and MDA-MB-231 cell lines by NNMT shRNA significantly inhibited cell growth in vitro, decreased tumorigenicity in mice and induced apoptosis. The silencing reciprocal effect of NNMT was confirmed by over-expressing NNMT in the MCF-7 and SK-BR-3 breast cancer cell lines which lack constitutive expression of NNMT. In addition, down-regulation of NNMT expression resulted in reducing expression of Bcl-2 and Bcl-xL, up-regulation of Bax, Puma, cleaved caspase-9, cleaved caspase-3 and cleaved PARP, increasing reactive oxygen species production and release of cytochrome c from mitochondria, and decreasing the phosphorylation of Akt and ERK1/2. These data suggest that down-regulation of NNMT induces apoptosis via the mitochondria-mediated pathway in breast cancer cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Apoptosis / physiology*
Blotting, Western
Breast Neoplasms / enzymology*
Cell Line, Tumor
Cytochromes c / metabolism
DNA Primers / genetics
Female
Flow Cytometry
Gene Expression Regulation, Neoplastic / physiology*
Humans
Mice
Mitochondria / metabolism
Mitochondria / physiology*
Nicotinamide N-Methyltransferase / metabolism*
RNA Interference
RNA, Small Interfering / metabolism
Reactive Oxygen Species / metabolism
Real-Time Polymerase Chain Reaction
Tetrazolium Salts
Thiazoles

Substances

DNA Primers
RNA, Small Interfering
Reactive Oxygen Species
Tetrazolium Salts
Thiazoles
Cytochromes c
NNMT protein, human
Nicotinamide N-Methyltransferase
thiazolyl blue

Grants and funding

This study was supported partly by the grants from National natural Science Foundation of China (81271914), Zhejiang Provincial Natural Science Foundation (LY12H16025), Science Foundation of Health Bureau of Zhejiang Province (Nos. 2008B114 and 2011KYA081), Science Foundation of Education Bureau of Zhejiang Province (Y201121182) and Funds for Key Program of the Science Technology Department Zhejiang Province (2012C13019-2). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.