Elevation of soluble guanylate cyclase suppresses proliferation and survival of human breast cancer cells.
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.
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan.
Hui-Chin
HC
Wen
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan.
Chih-Pin
CP
Chuu
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan.
Chen-Yu
CY
Chen
National Institute of Cancer Research, National Health Research Institutes, Miaoli County, Taiwan.
Shine-Gwo
SG
Shiah
Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.
Hsing-Jien
HJ
Kung
Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei City, Taiwan.
Kuang-Liang
KL
King
Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan.
Liang-Chen
LC
Su
Chest Department, Taipei Veterans General Hospital, Taipei City, Taiwan; Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei City, Taiwan.
Shi-Chuan
SC
Chang
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.
Chung-Ho
CH
Chang
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D002453:Cell Cycle; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D006152:Cyclic GMP / Q000378:metabolism*; D019175:DNA Methylation / Q000235:genetics; D000077209:Decitabine; D005260:Female; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D008819:Mice, Nude; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase
D018160:Receptors, Cytoplasmic and Nuclear; D009599:Nitroprusside; D009569:Nitric Oxide; D000077209:Decitabine; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP; D001374:Azacitidine; D001920:Bradykinin