Estrogen and growth factor receptor interactions in human breast and non-small cell lung cancer cells

Richard J. Pietras, Diana C. Márquez, Hsiao Wang Chen, Eugene Tsai, Olga Weinberg, Michael Fishbein

Research output: Contribution to journalArticlepeer-review

Abstract

Extranuclear estrogen receptors may mediate rapid effects of estradiol that communicate with nuclear receptors and contribute to proliferation of human cancers bearing these signaling proteins. To assess these growth-promoting pathways, we undertook controlled homogenization and fractionation of NIH-H23 non-small cell lung cancer cells. As many breast tumors, NIH-H23 cells express estrogen receptors (ER), with the bulk of specific estradiol binding in nuclear fractions. However, as in breast cells, a significant portion of specific, high-affinity estradiol-17β binding-sites are also enriched in plasma membranes of lung tumor cells. These estrogen binding-sites co-purify with plasma membrane-marker enzymes and are not significantly contaminated by cytosol or nuclei. On further purification of membrane caveolae from lung tumor cells, proteins recognized by monoclonal antibodies to nuclear ER-α and to ER-β were identified in close association with EGF receptor in caveolae. In parallel studies, ER-α and ER-β are also detected in nuclear and extranuclear sites in archival human breast and lung tumor samples and are noted to occur in clusters at the cell membrane by using confocal microscopy to visualize fluorescent-labeled monoclonal antibodies to ER-α. Data on site-directed mutagenesis of cysteine-447 in ER-α suggest that association of ER forms with membrane sites may depend on acylation of cysteine by palmitate. Estrogen-induced growth of MCF-7 breast cancer and NIH-H23 lung cancer cells in vitro correlated closely with acute hormonal activation of mitogen-activated protein kinase signaling and was significantly reduced by treatment with Faslodex, a pure anti-estrogen. Further, combination of Faslodex with selected growth factor receptor inhibitors elicited a more pronounced inhibiton of tumor cell growth. Thus, extranuclear forms of ER play a role in promoting downstream signaling for hormone-mediated proliferation and survival of breast, as well as lung, cancers and offer a new target for anti-tumor therapy.

Original languageEnglish (US)
Pages (from-to)372-381
Number of pages10
JournalSteroids
Volume70
Issue number5-7 SPEC. ISS.
DOIs
StatePublished - 2005
Externally publishedYes

Keywords

  • Breast cancer
  • EGF receptor
  • Estrogen receptor
  • HER-2 receptor
  • Lung cancer
  • Palmitoylation

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology
  • Pharmacology
  • Clinical Biochemistry
  • Organic Chemistry

Fingerprint

Dive into the research topics of 'Estrogen and growth factor receptor interactions in human breast and non-small cell lung cancer cells'. Together they form a unique fingerprint.

Cite this