Conjugated linoleic acid (CLA) up-regulates the estrogen-regulated cancer suppressor gene, protein tyrosine phosphatase gamma (PTPgama), in human breast cells

Anticancer Res. Jan-Feb 2006;26(1A):27-34.

Abstract

Background: Conjugated linoleic acid (CLA), a naturally occurring compound found in ruminants products, has been shown to possess anticancer properties in vivo and in vitro. There are several CLA isomers in ruminant-produced foods, among which t10, c12-CLA and c9, t11-CLA are the most potent. Protein tyrosine phosphatase gamma (PTPgamma) has been implicated as a tumor suppressor gene in kidney and lung cancers. Our previous results indicated that estradiol-17beta (E2)-induced suppression of PTPgamma may play a role in mammary tumorigenesis.

Materials and methods: The effects of t10, c12-CLA and c9, t11-CLA on PTPgamma mRNA expression in human breast epithelial cells and stromal cells, isolated from surgical specimens of mammoplasty and breast cancer patients, were detected and quantified by RT-PCR RESULTS: The PTPgamma mRNA expression was lower in cancer than in normal breast cells. Both t10, c12-CLA and c9, t11-CLA significantly (p < 0.05) increased the PTPgamma mRNA levels in primary cultured normal breast epithelial cells, normal breast stromal cells and breast cancer epithelial cells, but not in breast cancer stromal cells. t10, c12-CLA appeared to be the most active isomer in estrogen receptor a (ERalpha)-positive human breast cancer epithelial cells.

Conclusion: The results indicate that dietary CLA might serve as a chemo-preventive and chemo-therapeutic agent in human breast cancers by up-regulating the estrogen-regulated tumor suppressor gene, PTPgamma expression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / enzymology*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Epithelial Cells / drug effects
  • Epithelial Cells / enzymology
  • Estrogen Receptor alpha / biosynthesis
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Genes, Tumor Suppressor
  • Humans
  • Linoleic Acids, Conjugated / pharmacology*
  • Nerve Tissue Proteins / biosynthesis*
  • Nerve Tissue Proteins / genetics
  • Protein Tyrosine Phosphatases / biosynthesis*
  • Protein Tyrosine Phosphatases / genetics
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Receptor-Like Protein Tyrosine Phosphatases, Class 5
  • Stromal Cells / drug effects
  • Stromal Cells / enzymology
  • Up-Regulation / drug effects

Substances

  • Estrogen Receptor alpha
  • Linoleic Acids, Conjugated
  • Nerve Tissue Proteins
  • RNA, Messenger
  • cis-9, trans-11-conjugated linoleic acid
  • trans-10,cis-12-conjugated linoleic acid
  • PTPRG protein, human
  • Protein Tyrosine Phosphatases
  • Receptor-Like Protein Tyrosine Phosphatases, Class 5