1. Academic Validation
  2. Inhibition of Interleukin 10 Transcription through the SMAD2/3 Signaling Pathway by Ca2+-Activated K+ Channel KCa3.1 Activation in Human T-Cell Lymphoma HuT-78 Cells

Inhibition of Interleukin 10 Transcription through the SMAD2/3 Signaling Pathway by Ca2+-Activated K+ Channel KCa3.1 Activation in Human T-Cell Lymphoma HuT-78 Cells

  • Mol Pharmacol. 2019 Mar;95(3):294-302. doi: 10.1124/mol.118.114405.
Miki Matsui 1 Junko Kajikuri 1 Hiroaki Kito 1 Kyoko Endo 1 Yuki Hasegawa 1 Shinya Murate 1 Susumu Ohya 2
Affiliations

Affiliations

  • 1 Department of Pharmacology, Kyoto Pharmaceutical University, Kyoto, Japan (M.M., K.E., Y.H.) and Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan (M.M., J.K., H.K., K.E., S.M., S.O.).
  • 2 Department of Pharmacology, Kyoto Pharmaceutical University, Kyoto, Japan (M.M., K.E., Y.H.) and Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan (M.M., J.K., H.K., K.E., S.M., S.O.) [email protected].
Abstract

The hyperpolarization induced by intermediate-conductance Ca2+-activated K+ channel (KCa3.1) activation increases the driving force for Ca2+ influx, which generally promotes cell proliferation, migration, and cytokine production in immunocompetent cells. Interleukin-10 (IL-10) from tumor-infiltrating lymphocytes and macrophages, lymphoma, and carcinoma cells facilitates escape from Cancer immune surveillance; however, the role of KCa3.1 in IL-10 production remains unclear. The objective of the present study was to elucidate the involvement of KCa3.1 in IL-10 expression and production using the human T-cell lymphoma HuT-78 cells. In HuT-78 cells, IL-10 gene expression and production were reduced by treatment with the KCa3.1 activator, as 6-hour Western blotting showed that the protein expression ratio of phosphorylated SMAD2 (P-Smad2)/SMAD2, but not P-Smad3/SMAD3, was decreased by the treatment with KCa3.1 activator in HuT-78 cells. Concomitant with this, the nuclear translocation of P-Smad2 was inhibited by KCa3.1 activator. Furthermore, the KCa3.1 activator-induced transcriptional repression of IL-10 disappeared with pretreatment with the Calmodulin kinase II (CaMKII) inhibitor KN-62 for 1 hour, and KCa3.1 activator-induced decreases in the nuclear translocation of P-Smad2 were also prevented by pretreatment with KN-62. Taken together, the KCa3.1 activator-induced transcriptional repression of IL-10 is due to the inhibition of the nuclear translocation of P-Smad2 in HuT-78 cells, resulting in the prevention of P-Smad2/3 complex formation in nuclei, and the activation of CaMKII induced by KCa3.1 activators suppresses the constitutive activation of P-Smad2/3 in HuT-78 cells. Therefore, KCa3.1 activators have potential as a therapeutic option to suppress the tumor-promoting activities of IL-10.

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