Publications by authors named "Laurie M Bradley"

2 Publications

  • Page 1 of 1

Role of the insulin-like growth factor system on an estrogen-dependent cancer phenotype in the MCF-7 human breast cancer cell line.

J Steroid Biochem Mol Biol 2008 Mar 8;109(1-2):185-96. Epub 2008 Feb 8.

Department of Environmental Health and Toxicology, School of Public Health, State University at Albany, Albany, NY, USA.

We previously established that exposure of the estrogen receptor (ER) alpha positive MCF-7 human breast cancer cell line to 17-beta-estradiol (E2) results in the post-confluent development of multilayered cellular aggregates (foci) which is consistent with the in vivo cancer phenotype of uncontrolled cellular proliferation. In this investigation, the interaction between the insulin-like growth factor receptor (IGF-IR) and ER-signaling systems in regard to post-confluent focus development was studied. We demonstrated that focus development requires the presence of E2 and insulin-like growth factor I (IGF-I) or insulin-like growth factor II (IGF-II), as well as intact ER and IGF-IR. Focus development in MCF-7 cultures, which occurs only after formation of a confluent monolayer, coincides with E2 regulation of key members of the IGF-signaling system such as IGF-IR, IGF-II, insulin receptor substrate 1 (IRS-1), and insulin-like growth factor binding protein 3 (IGFBP-3), as demonstrated by real-time polymerase chain reaction (PCR). To establish the relevancy of an intact IGF-signaling system for foci formation, we generated stable clones from MCF-7 with IGF-IR suppressed by siRNA. Results from these studies implicate signaling through the IGF-IR to be an integral requirement for E2-dependent post-confluent proliferation and focus formation. In summary, these studies establish the interactive roles of IGFs and E2 in the post-confluent development of foci, and will allow subsequent identification of targets for therapeutic intervention in the control and treatment of estrogen-dependent breast cancer.
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http://dx.doi.org/10.1016/j.jsbmb.2007.10.006DOI Listing
March 2008

Inhibition of MCF-7 breast cancer cell proliferation by MCF-10A breast epithelial cells in coculture.

Cell Biol Int 2006 Mar 19;30(3):227-38. Epub 2006 Jan 19.

Wadsworth Center, New York State Department of Health, PO Box 509, Albany, NY 12201-0509, USA.

A coculture system was developed to investigate the interactions between MCF-10A breast epithelial cells and MCF-7 breast cancer cells stably expressing the green fluorescent protein (MCF-7-GFP). Studies with this MCF-10A/MCF-7-GFP coculture system on microtiter plates and on reconstituted basement membrane (Matrigel), revealed paracrine inhibition of MCF-7-GFP cell proliferation. Epidermal growth factor, which in monocultures modestly enhanced MCF-7-GFP and markedly increased MCF-10A cell proliferation, greatly inhibited MCF-7-GFP cell proliferation in MCF-10A/MCF-7-GFP cocultures. 17beta-Estradiol, which stimulated MCF-7-GFP but not MCF-10A cell proliferation in monoculture, inhibited MCF-7-GFP cell proliferation in MCF-10A/MCF-7-GFP cocultures, an effect that was blocked by the antiestrogen, ICI 182,780. On Matrigel, complex MCF-10A/MCF-7-GFP cellular interactions were observed in real time that resulted in the formation of acinus-like structures. These results indicate a role of normal epithelial cells in inhibiting tumor-cell proliferation and demonstrate the utility of this coculture system as a model of early paracrine control of breast cancer.
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http://dx.doi.org/10.1016/j.cellbi.2005.11.006DOI Listing
March 2006