scholarly journals Primary keratinocytes have an adhesion dependent S phase checkpoint that is absent in immortalized cell lines

Oncogene ◽  
1998 ◽  
Vol 17 (24) ◽  
pp. 3083-3092 ◽  
Author(s):  
Paul J Hauser ◽  
Deepak Agrawal ◽  
W J Pledger
Keyword(s):  
Cell Lines ◽  
S Phase ◽  
Primary Keratinocytes ◽  
Immortalized Cell Lines ◽  
Immortalized Cell ◽  
S Phase Checkpoint

Isolation of immortalized, INK4a/ARF-deficient cells from the subventricular zone after in utero N-ethyl-N-nitrosourea exposure

2005 ◽  
Vol 102 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Todd M. Savarese ◽  
Taichang Jang ◽  
Hoi Pang Low ◽  
Rebecca Salmonsen ◽  
N. Scott Litofsky ◽  
...  
Keyword(s):  
Cell Lines ◽  
Subventricular Zone ◽  
Defined Medium ◽  
In Utero ◽  
Homozygous Deletion ◽  
Content Type ◽  
Immortalized Cell Lines ◽  
Immortalized Cell ◽  
Fine Print

Object. Brain tumors, including gliomas, develop several months after rats are exposed in utero to N-ethyl-N-nitrosourea (ENU). Although pathological changes cannot be detected until these animals are several weeks old, the process that eventually leads to glioma formation must begin soon after exposure given the rapid clearance of the carcinogen and the observation that transformation of brain cells isolated soon after exposure occasionally occurs. This model can therefore potentially provide useful insights about the early events that precede overt glioma formation. The authors hypothesized that future glioma cells arise from stem/progenitor cells residing in or near the subventricular zone (SVZ) of the brain. Methods. Cells obtained from the SVZ or corpus striatum in ENU-exposed and control rats were cultured in an epidermal growth factor (EGF)-containing, chemically defined medium. Usually, rat SVZ cells cultured in this manner (neurospheres) are nestin-positive, undifferentiated, and EGF-dependent and undergo cell senescence. Consistent with these prior observations, control SVZ cells undergo senescence by the 12th to 15th doubling (20 of 20 cultures). In contrast, three of 15 cultures of cells derived from the SVZs of individual ENU-treated rats continue to proliferate for more than 60 cell passages. Each of these nestin-expressing immortalized cell lines harbored a common homozygous deletion spanning the INK4a/ARF locus and was unable to differentiate into neural lineages after exposure to specific in vitro stimuli. Nevertheless, unlike the rat C6 glioma cell line, these immortalized cell lines demonstrate EGF dependence and low clonogenicity in soft agar and did not form tumors after intracranial transplantation. Conclusions. Data in this study indicated that immortalized cells may represent glioma precursors that reside in the area of the SVZ after ENU exposure that may serve as a reservoir for further genetic and epigenetic hits that could eventually result in a full glioma phenotype.

scholarly journals Immortalization of equine trophoblast cell lines of chorionic girdle cell lineage by simian virus-40 large T antigen

2001 ◽  
Vol 171 (1) ◽  
pp. 45-55 ◽  
Author(s):  
TM Thway ◽  
CM Clay ◽  
JK Maher ◽  
DK Reed ◽  
KJ McDowell ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cell Lineage ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Alpha Subunit ◽  
Subunit Gene ◽  
Immortalized Cell Lines ◽  
Subunit Expression ◽  
Immortalized Cell

Immortalized cell lines have many potential experimental applications including the analysis of molecular mechanisms underlying cell-specific gene expression. We have utilized a recombinant retrovirus encoding the simian virus-40 (SV-40) large T antigen to construct several immortalized cell lines of equine chorionic girdle cell lineage - the progenitor cells that differentiate into the equine chorionic gonadotropin (eCG) producing endometrial cups. Morphologically, the immortalized cell lines appear similar to normal chorionic girdle cells. Derivation of the immortalized cell lines from a chorionic girdle cell lineage was verified by immunological detection of cell-surface antigens specific to equine invasive trophoblasts. The cell lines differed, however, from mature chorionic girdle cells or endometrial cup cells in that they did not produce eCG and did express MHC class I molecules. Thus, these cell lines appear to have been arrested at a stage of development prior to final differentiation into endometrial cup cells. It was also determined that some of these cell lines as well as endometrial cups express the estrogen receptor-related receptor beta gene, but not the glial cell missing gene (GCMa) both of which are expressed in the murine and human placenta. Among these cell lines, three (eCG 50.5, 100.6 and 500.1) express eCG alpha mRNA. Since regulation of eCG alpha subunit gene is largely unknown, we investigated the signal transduction pathways regulating the eCG alpha subunit gene. Both activators of protein kinase A (PKA) and protein kinase C (PKC) induced the expression of eCG alpha subunit expression 3.2 (P<0.05)- and 1.9 (P<0.05)-fold respectively, in the eCG 500.1 cell line. However, activation of these pathways failed to induce eCG beta subunit expression. In conclusion, lines of equine trophoblast cells have been immortalized that display markers characteristic of those with the equine chorionic girdle and endometrial cup cell lineage. A subset of these cells expresses the eCG alpha subunit gene which is responsive to activators of the PKA and PKC signal transduction pathways.

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