Up‐Regulation of Transient Receptor Potential Melastatin 6 Channel Expression by Tumor Necrosis Factor‐α in the Presence of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Abstract

Anti-epidermal growth factor receptor (EGFR) drugs such as erlotinib and gefitinib cause a side effect of hypomagnesemia, but chemotherapy to treat this has not yet been developed. The transient receptor potential melastatin 6 (TRPM6) channel is involved in the reabsorption of Mg in the renal tubule. We reported previously that the expression of TRPM6 is up-regulated by epidermal growth factor (EGF) in renal tubular epithelial NRK-52E and HEK293 cells. EGF-induced elevation of TRPM6 expression was inhibited by erlotinib, gefitinib, and lapatinib. We found that tumor necrosis factor-α (TNF-α) increases TRPM6 expression in the presence of erlotinib. Therefore, we investigated what molecules are involved in the up-regulation of TRPM6 expression by TNF-α. EGF increased the levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (p-ERK1/2), which were inhibited by erlotinib. TNF-α did not change p-ERK1/2 levels, but increased the phosphorylation and nuclear localization of nuclear factor-κB (NF-κB), which were blocked by the NF-κB inhibitors BAY 11-7082 and pyrrolidinedithiocarbamate ammonium. Similarly, luciferase reporter activity of human TRPM6 was increased by TNF-α, which was blocked by NF-κB inhibitors, and was inhibited by a mutation in the κB-binding site in the proximal region of the TRPM6 promoter. A chromatin immunoprecipitation assay revealed that NF-κB binds to the κB-binding site, which was blocked by NF-κB inhibitors. In the presence of erlotinib, TNF-α increased Mg influx, which was blocked by NF-κB inhibitors. These results suggest that TNF-α reverses the reduction in Mg reabsorption caused by anti-EGFR drugs. J. Cell. Physiol. 232: 2841-2850, 2017. © 2016 Wiley Periodicals, Inc.

Cyanidin Increases the Expression of Mg2+ Transport Carriers Mediated by the Activation of PPARα in Colonic Epithelial MCE301 Cells

“…The transcriptional mechanisms of TRPM6 and CNNM4 genes have not been clarified in detail. Thus far, we reported that EGF, tumor necrosis factor-α, and PPARγ agonists increased the mRNA levels of TRPM6 in renal tubular epithelial cells [22,31,32]. In contrast, there are no reports concerning the transcriptional regulatory factor of CNNM4.…”

“…Cytoplasmic extracts, which include plasma membrane and cytosolic proteins, were prepared, as described previously [22]. The aliquots were applied to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto a polyvinylidene fluoride membrane.…”

Upregulation of transient receptor potential melastatin 6 channel expression by rosiglitazone and all‐trans‐retinoic acid in erlotinib‐treated renal tubular epithelial cells

“…Although the reabsorption rate is only 5-10% in this segment (Dai et al, 2001), homozygous deletion of TRPM6 is embryonic lethal and its heterozygous deletion results in a mild hypomagnesemia in mice (Walder et al, 2009;Woudenberg-Vrenken, Sukinta, van der Kemp, Bindels, & Hoenderop, 2011 (Dimke et al, 2010), and CDDP-and cyclosporine-treated rats (Ledeganck, Boulet, Bogers, Verpooten, & De Winter, 2013;Ledeganck et al, 2011). So far, we reported that EGF increases TRPM6 expression mediated via the activation of EGFR/ERK/c-Fos (Ikari et al, 2010) and erlotinib inhibits the EGFinduced elevation of TRPM6 in NRK-52E cells (Furukawa et al, 2017). EGF has another function that increases cell surface localization of TRPM6 mediated via promoting trafficking of TRPM6 (van der Wijst, Hoenderop, & Bindels, 2009).…”

Sodium Citrate Increases Expression and Flux of Mg2+ Transport Carriers Mediated by Activation of MEK/ERK/c-Fos Pathway in Renal Tubular Epithelial Cells

“…So far, we reported that epidermal growth factor increases the expression levels of TRPM6 mediated by the activation of MEK/ERK/c-Fos pathway using renal epithelial NRK-52E cells [ 19 , 20 ]. Immunosuppressants including cyclosporine A and tyrosine kinase inhibitor erlotinib, an anticancer drug used in the treatment of non-small lung cancer, induce the reduction of TRPM6 expression mediated by the inhibition of MEK/ERK/c-Fos pathway [ 21 , 22 ]. Therefore, the MEK/ERK/c-Fos pathway may play a pivotal role in Mg 2+ homeostasis under physiological conditions.…”

“…The change in [Mg 2+ ] i was determined using a Mg 2+ -sensitive fluorescent dye, Mag-fura 2 AM, as described previously [ 21 , 22 ]. MgCl 2 (final concentration 1 mM) was added to the nominally Mg 2+ -free Hanks Balanced Salt Solution (HBSS) containing 137 mM NaCl, 5.4 mM KCl, 4.2 mM NaHCO 3 , 3 mM Na 2 HPO 4 , 0.4 mM KH 2 PO 4 , 5 mM Hepes, 1 mM CaCl 2 , and 10 mM glucose, immediately after the measurement start.…”