A Human Breast Epithelial Cell Type with Stem Cell Characteristics as Target Cells for Carcinogenesis

Abstract

Two types of human breast epithelial cells (HBEC) have been characterized. In contrast to Type II HBEC, which express basal epithelial cell phenotypes, Type I HBEC are deficient in gap junctional intercellular communication and are capable of anchorage-independent growth and of expressing luminal epithelial cell markers, estrogen receptors, and stem cell characteristics (i.e. the ability to differentiate into other cell types and to form budding/ductal organoids on Matrigel). A comparative study of these two types of cells has revealed a high susceptibility of Type I HBEC to immortalization by SV40 large T antigen, although both types of cells are equally capable of acquiring an extended life span (bypassing senescence) after transfection with SV40. The immortalization was accompanied by elevation of a low level of telomerase activity in the parental cells after mid-passage ( approximately 60 cumulative population doubling levels). Thus HBEC do have a low level of telomerase activity, and Type I HBEC with stem cell characteristics are more susceptible to telomerase activation and immortalization, a mechanism which might qualify them as target cells for breast carcinogenesis. The immortalized Type I HBEC can be converted to highly tumorigenic cells by further treatment with X rays (2 Gy x 2) and transfection with a mutated ERBB2 (also known as NEU) oncogene, resulting in the expression of p185(ERBB2) which is tyrosine phosphorylated.

Formation and characterization of three dimensional human hepatocyte cell line spheroids on chitosan matrix for in vitro tissue engineering applications

“…Cells from adult pancreatic islands are capable of self-assembling to form aggregates that secrete insulin (Halban et al 1987). Threedimensional organoids were formed from normal human adult breast epithelial stem cells, which were almost identical to those found in vivo (Chang et al 2001).…”

Evolution of Energy Metabolism, Stem Cells and Cancer Stem Cells: How the Warburg and Barker Hypotheses Might Be Linked

“…Given two types of cancer cells, those that never express their connexin genes (e.g., HeLa and MCF-7) (81, 82), and whose connexin genes are normal and expressed (e.g., cells with active oncogenes), the strategies would have to be different (64). In the case of human breast cancer, MCF-7 (estrogen-receptor and Oct4A positive and Cx43 negative), seem to share many phenotypes as did the normal human breast stem cells and SV40-immortalized and neoplasticallytransformed human adult breast stem cells (52).…”

Characterization of hybrid cells derived from spontaneous fusion events between breast epithelial cells exhibiting stem-like characteristics and breast cancer cells

“…The M13SV1 breast epithelial cell line, exhibiting stem-like characteristics, [30] was kindly provided by James E. Trosko (Michigan State University, East Lansing, MI) and was cultivated in MSU-1 basal media (Sigma-Aldrich, Taufkirchen, Germany) supplemented with 10% fetal calf serum (PAA Laboratories, Linz, Austria), 1% Penicillin/ Streptomycin (100 U/ml Penicillin, 0.1 mg/ml Streptomycin; PAA Laboratories, Linz, Austria), 10 lg/ml human recombinant EGF, 5 lg/ml human recombinant Insulin, 0.5 lg/ml Hydrocortisone, 4 lg/ml human Transferrin and 10 nM b-Estradiol (all chemicals were purchased from Sigma-Aldrich, Taufkirchen, Germany) at 37°C and 5% CO 2 in a humidified atmosphere. The breast cancer cell lines HS578T (HTB-126; LGC Standards GmbH, Wesel, Germany) and MDA-MB-435 (HTB-129; LGC Standards GmbH, Wesel, Germany) were maintained in RPMI 1640 media (HS578T; PAA Laboratories, Linz, Austria) and DMEM (MDA-MB-435; PAA Laboratories, Linz, Austria), respectively, supplemented with 10% FCS and 1% Penicillin/Streptomycin at 37°C and 5% CO 2 in a humidified atmosphere.…”