Characterization of gap junctional intercellular communication in immortalized human pancreatic ductal epithelial cells with stem cell characteristics.
BACKGROUND
Gap junctional intercellular communication has been implicated in the homeostatic regulation of cell growth, differentiation, and apoptosis. Cancer cells, which have been viewed as "partially blocked stem cells," and which lack the ability for growth control, terminal differentiation, and apoptosis, also lack functional gap junctional communication.


OBJECTIVE
A clone of a human pancreatic ductal epithelial cell line, H6c7, derived after immortalization with human papilloma virus, was used to examine gap junctional intercellular communication and the ability to differentiate under different growth conditions.


RESULTS
The cells showed characteristic epithelial morphology on standard tissue culture dishes. When placed on Matrigel they showed phenotypical changes with extensive ductal organization and budding structures. In growth medium containing hormones and growth factors, these cells were gap junctional intercellular communication (GJIC)-incompetent. In the presence of c-AMP elevating agents, isobutylmethylxanthine, and forskolin, in basal medium that did not contain the hormones and growth factors, the cells became GJIC-competent and expressed connexin43 gap junction protein within 48 hours after treatment. RT-PCR analyses of the cells under different growth conditions showed that the cells expressed, and genes when cultured in the basal medium with c-AMP elevating agents. They also expressed the gene that did not change with c-AMP treatment. H6c7 cells also have the capacity to turn on an ectopic insulin promoter reporter gene.


CONCLUSIONS
Our data suggest that the immortalized H6c7 cells retain stem-like characteristics and have the potential to differentiate into duct-like structures and perhaps insulin-producing cells.
Tai
Mei-Hui
MH
Department of Pediatrics and Human Development, Michigan State University, East Lansing, Michigan 48824, USA.
Olson
L Karl
LK
Madhukar
Burra V
BV
Linning
Katrina D
KD
Van Camp
Loretta
L
Tsao
Ming-Sound
MS
Trosko
James E
JE
D002450:Cell Communication; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002999:Clone Cells; D017630:Connexins / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D017629:Gap Junctions / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000235:genetics; D010183:Pancreatic Ducts / Q000166:cytology / Q000502:physiology*; D027383:Papillomaviridae / Q000235:genetics; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
D017630:Connexins; D007328:Insulin; D000242:Cyclic AMP