Accelerated malignant conversion of human HBL-100 cells by the v-Ki-ras oncogene

Characterisation of human thyroid epithelial cells immortalised in vitro by simian virus 40 DNA transfection

“…It is not clear why SV40-transformed human epithelial cells are usually non-tumorigenic in nude mice (an exception being late-passage SV40-transformed keratinocytes; described by Brown & Gallimore, 1987), while SV40-transformed rodent epithelial cells, such as rat hepatocytes (Woodworth et al, 1988), are often strongly tumorigenic (Freedman & Shin, 1978). The fact that some SV40-transformed human epithelial cell lines, such as the 184A1 mammary line (Clark et al, 1988) and the HBL-100 mammary line (Saint-Ruf et al, 1988), can be converted to tumorigenicity by ras oncogenes (activated Ha-ras and Ki-ras respectively) strongly suggests that the parent lines are indeed incompletely transformed. Both of the thyroid cell lines (HTori-3 and HTori-5) subjected to chromosome analysis were aneuploid, which is to be expected after transformation by SV40.…”

Concomitant Alterations of Microfilaments and Microtubules in Human Epithelial Cells (HBL-100) in Relation to Their Malignant Conversion

“…A morphological and biochemical charac terization of HBL-100 cells used in this study has been described previously [20,23], …”

“…Superinfected with Ki-MSV Accelerated malignant conversion of early passage HBL-100 cells has been ob tained by superinfection with Ki-MSV virus (HBL/Ki-MSV) [23]. The cytoskeleton of these tumorigenic cells, studied at p. 28, dis played a highly disorganized aspect.…”

“…HBLT-12 is a cell line derived from a tumor induced in a nude athymic mouse after subcutaneous injection of late passage (p. 70) tumorigenic HBL-100 cells. HBL/Kj-MSV is a cell line obtained in vitro after superinfection of early passage (p. 28) nontumorigenic HBL-100 cells with Ki-MSV and thus rendered tumorigenic for athymic nude mice [23]. All these lines were routinely grown in Eagle's minimum essential medium supplemented with 10% newborn calf serum.…”

“…Despite displaying properties charac teristic of transformation since its early in vitro passages, it is capable of producing pro gressively growing tumors in nude mice only after long term culture (~ p. 70). Malignant conversion of early passage HBL-100 cells can also be achieved after superinfection with Kirsten murine sarcoma virus (Ki-MSV) which contains an activated Ki-ras oncogene [23]. These cells offer, therefore, the opportunity to investigate the action of a primary hit caused by SV 40 infection, likely to be responsible for cell immortalization, and the influence of secondary events either spontaneous or induced by transforming DNA and oncogene expression.…”