Analysis of proviral integration in human mammary epithelial cell lines immortalized by retroviral infection with a temperature‐sensitive SV40 T‐antigen construct

Abstract

A panel of eight conditionally immortal lines derived by infection of human breast epithelial cells with an amphotropic retrovirus transducing a ts mutant of SV40 large T-antigen was analyzed with respect to individual retroviral integration patterns. Each line contained multiple integration sites which were clonal and stable over extended passage. Similar integration patterns were observed between individual lines arising separately from the same stock of pre-immortal cells, suggesting a common progenitor. Retroviral integration analysis of pre-immortal cells at different stages of pre-crisis growth showed changes indicative of a progressive transition from polyclonality to clonality as the cells approached crisis. Each of the immortal lines contained a sub-set of the integration sites of their pre-immortal progenitors, with individual combinations and copy numbers of sites. Since all the cell lines appeared to originate from single foci in separate flasks, it is likely that each set arose from a common clone of pre-immortal cells as the result of separate genetic events. There was no evidence from this analysis to suggest that specific integration sites played any part either in the selection of pre-crisis clones or in the subsequent establishment of immortal lines.

BORIS, a paralogue of the transcription factor, CTCF, is aberrantly expressed in breast tumours

“…The two non-malignant cell lines were HBL100 (Gaffney, 1982) and HB4a. The HB4a cells were established from normal breast luminal cells immortalised with SV40 T-antigen (Stamps et al, 1994). Malignant breast cell lines included six ER-positive (ER þ ) cells originating from human breast carcinomas (T47D, MCF7, BT474, CAMA1, ZR75-1 and ZR75-30).…”

BRK tyrosine kinase expression in a high proportion of human breast carcinomas

“…RNase protection was performed with a brk probe on RNA puri®ed from yeast, CAL51 carcinoma cells or T-47D carcinoma cells. A probe for GAPDH was used to con®rm the integrity of the CAL51 and T-47D RNA epithelial cells puri®ed from normal human mammary tissue (Stamps et al, 1994), and retain many features of normal mammary luminal epithelial cells (Kamalati et al, 1996a). Of these, the best characterised are the HB4a cells.…”

“…Immortalized mammary cell lines HB1a, 2a, 2c, 2d, 4a, 4b and 4c, derived as described (Stamps et al, 1994), were cultured in RPMI 1640, 10% foetal bovine serum (FBS), hydrocortisone (5 mg/ml), cholera toxin (0.1 mg/ml) and insulin (5 mg/ml). MCF 10A (ATCC-CRL 10317) were grown in DMEM Hams F12, 5% horse serum, hydrocortisone (0.5 mg/ml), cholera toxin (0.1 mg/ml), insulin (5 mg/ml) and EGF (0.01 mg/ml).…”

A high-resolution integrated analysis of genetic and expression profiles of breast cancer cell lines

“…The following cell lines were used in this study: (1) 24 breast cancer cell lines-BT-474, CAL51, DU4475, GI101, HBL100, HMT3552, Hs578T, MCF7, MDA-MB-134, MDA-MB-157, MDA-MB-175, MDA-MB-231, MDA-MB-361, MDA-MB-453, MDA-MB-468, MDA-MB-469, PMC42, SKBR3, SKBR5, SKBR7, T47D, ZR75.1, ZR75.30 and UACC3199, (2) HB4a, a cell line derived from immortalisation of normal breast luminal epithelial cells [10], (3) two non-tumourigeneic breast epithelial cell lines (MCF10A and MCF12A), (4) human mammary epithelial cells (HMECs), (5) pools of immunomagnetically sorted normal primary breast cells representing normal luminal cells [11], myoepithelial cells [11] intra-lobular fibroblasts [12] and endothelial cells [12].…”