TY - JOUR
T1 - K(ATP) channels regulate mitogenically induced proliferation in primary rat hepatocytes and human liver cell lines
T2 - Implications for liver growth control and potential therapeutic targeting
AU - Malhi, Harmeet
AU - Irani, Adil N.
AU - Rajvanshi, Pankaj
AU - Suadicani, Sylvia O.
AU - Spray, David C.
AU - McDonald, Thomas V.
AU - Gupta, Sanjeev
PY - 2000/8/25
Y1 - 2000/8/25
N2 - To determine whether K(ATP) channels control liver growth, we used primary rat hepatocytes and several human cancer cell lines for assays. K(ATP) channel openers (minoxidil, cromakalim, and pinacidil) increased cellular DNA synthesis, whereas K(ATP) channel blockers (quinidine and glibenclamide) attenuated DNA synthesis. The channel inhibitor glibenclamide decreased the clonogenicity of HepG2 cells without inducing cytotoxicity or apoptosis. To demonstrate the specificity of drugs for K+ channels, whole-cell patch-clamp recordings were made. Hepatocytes revealed K+ currents with K(ATP) channel properties. These K+ currents were augmented by minoxidil and pinacidil and attenuated by glibenclamide as well as tetraethylammonium, in agreement with established responses of K(ATP) channels. Reverse transcription of total cellular RNA followed by polymerase chain reaction showed expression of K(ATP) channel-specific subunits in rat hepatocytes and human liver cell lines. Calcium fluxes were unperturbed in glibenclamide-treated HepG2 cells and primary rat hepatocytes following induction with ATP and hepatocyte growth factor, respectively, suggesting that the effect of K(ATP) channel activity upon hepatocyte proliferation was not simply due to indirect modulation of intracellular calcium. The regulation of mitogen-related hepatocyte proliferation by K(ATP) channels advances our insights into liver growth control. The findings have implications in mechanisms concerning liver development, regeneration, and oncogenesis.
AB - To determine whether K(ATP) channels control liver growth, we used primary rat hepatocytes and several human cancer cell lines for assays. K(ATP) channel openers (minoxidil, cromakalim, and pinacidil) increased cellular DNA synthesis, whereas K(ATP) channel blockers (quinidine and glibenclamide) attenuated DNA synthesis. The channel inhibitor glibenclamide decreased the clonogenicity of HepG2 cells without inducing cytotoxicity or apoptosis. To demonstrate the specificity of drugs for K+ channels, whole-cell patch-clamp recordings were made. Hepatocytes revealed K+ currents with K(ATP) channel properties. These K+ currents were augmented by minoxidil and pinacidil and attenuated by glibenclamide as well as tetraethylammonium, in agreement with established responses of K(ATP) channels. Reverse transcription of total cellular RNA followed by polymerase chain reaction showed expression of K(ATP) channel-specific subunits in rat hepatocytes and human liver cell lines. Calcium fluxes were unperturbed in glibenclamide-treated HepG2 cells and primary rat hepatocytes following induction with ATP and hepatocyte growth factor, respectively, suggesting that the effect of K(ATP) channel activity upon hepatocyte proliferation was not simply due to indirect modulation of intracellular calcium. The regulation of mitogen-related hepatocyte proliferation by K(ATP) channels advances our insights into liver growth control. The findings have implications in mechanisms concerning liver development, regeneration, and oncogenesis.
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U2 - 10.1074/jbc.M001576200
DO - 10.1074/jbc.M001576200
M3 - Article
C2 - 10862612
AN - SCOPUS:0034713931
SN - 0021-9258
VL - 275
SP - 26050
EP - 26057
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 34
ER -