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PLoS One. 2015 Apr 30;10(4):e0125518. doi: 10.1371/journal.pone.0125518. eCollection 2015.

Elevation of soluble guanylate cyclase suppresses proliferation and survival of human breast cancer cells.

Author information

1
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan.
2
National Institute of Cancer Research, National Health Research Institutes, Miaoli County, Taiwan.
3
Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.
4
Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei City, Taiwan.
5
Chest Department, Taipei Veterans General Hospital, Taipei City, Taiwan; Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei City, Taiwan.
6
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan; Graduate Institute of Basic Medical Science, Ph.D. Program of Aging, China Medical University, Taichung City, Taiwan.

Abstract

Nitric oxide (NO) is an essential signaling molecule in biological systems. Soluble guanylate cyclase (sGC), composing of α1 and β1 subunit, is the receptor for NO. Using radioimmunoassay, we discovered that activation of sGC by treatment with bradykinin or sodium nitroprusside (SNP) is impaired in MCF-7 and MDA-MB-231 breast cancer cells as compared to normal breast epithelial 184A1 cells. The 184A1 cells expressed both sGC α1 and sGCβ1 mRNAs. However, levels of sGCβ1 mRNAs were relatively lower in MCF-7 cells while both mRNA of sGC subunits were absent in MDA-MB-231 cells. Treatment with DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) increased mRNA levels of both sGCα1 and sGCβ1 in MDA-MB-231 cells but only sGCβ1 mRNAs in MCF-7 cells. The 5-aza-dC treatment increased the SNP-induced cGMP production in MCF-7 and MDA-MB-231, but not in 184A1 cells. Bisulfite sequencing revealed that the promoter of sGCα1 in MDA-MB-231 cells and promoter of sGCβ1 in MCF-7 cells were methylated. Promoter hypermethylation of sGCα1 and sGCβ1 was found in 1 out of 10 breast cancer patients. Over-expression of both sGC subunits in MDA-MB-231 cells induced apoptosis and growth inhibition in vitro as well as reduced tumor incidence and tumor growth rate of MDA-MB-231 xenografts in nude mice. Elevation of sGC reduced protein abundance of Bcl-2, Bcl-xL, Cdc2, Cdc25A, Cyclin B1, Cyclin D1, Cdk6, c-Myc, and Skp2 while increased protein expression of p53. Our study demonstrated that down-regulation of sGC, partially due to promoter methylation, provides growth and survival advantage in human breast cancer cells.

PMID:
25928539
PMCID:
PMC4416047
DOI:
10.1371/journal.pone.0125518
[Indexed for MEDLINE]
Free PMC Article

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