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Objectives. Our study aimed to explore the role of the potassium channel KCNK1 in head and neck squamous cell carcinoma, focusing on its impact on tumor growth, invasion, and metastasis. We also investigated the therapeutic potential of quinidine, a known KCNK1 inhibitor, in both in vitro cell lines and a zebrafish patient-derived xenograft (PDX) model. Methods. We established primary cell cultures from head and neck cancer tissues and employed the FaDu cell line for in vitro studies, modulating KCNK1 expression through overexpression and knockdown techniques. We evaluated cell migration, invasion, and proliferation. Additionally, we developed a zebrafish PDX model to assess the impact of quinidine on tumor growth and metastasis in vivo. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted to elucidate the molecular mechanisms underlying the role of KCNK1 in cancer progression. Results. Overexpression of KCNK1 in FaDu cells resulted in enhanced cell migration and invasion, whereas its knockdown diminished these processes. In the zebrafish PDX model, quinidine markedly inhibited tumor growth and metastasis, demonstrating a significant reduction in tumor volume and micrometastasis rates compared to the control groups. The molecular analyses indicated that KCNK1 plays a role in critical signaling pathways associated with tumor growth, such as the Ras and MAPK pathways. Conclusion. Our findings highlight the critical role of KCNK1 in promoting tumor growth and metastasis in head and neck cancer. The inhibitory effect of quinidine on tumor progression in the zebrafish PDX model highlights the therapeutic potential of targeting KCNK1. These results suggest that KCNK1 could serve as a valuable therapeutic target for head and neck cancer, warranting further investigation into treatments that target KCNK1.

Abstract Background This study aimed to explore the expression, molecular mechanism and its biological function of potassium two pore domain channel subfamily K member 1 (KCNK1) in bladder cancer (BC). Methods We integrated large numbers of external samples (n = 1486) to assess KCNK1 mRNA expression levels and collected in-house samples (n = 245) for immunohistochemistry (IHC) experiments to validate at the KCNK1 protein level. Single-cell RNA sequencing (scRNA-seq) analysis was performed to further assess KCNK1 expression and cellular communication. The transcriptional regulatory mechanisms of KCNK1 expression were explored by ChIP-seq, ATAC-seq and ChIA-PET data. Highly expressed co-expressed genes (HECEGs) of KCNK1 were used to explore potential signalling pathways. Furthermore, the immunoassay, clinical significance and molecular docking of KCNK1 were calculated. Results KCNK1 mRNA was significantly overexpressed in BC (SMD = 0.58, 95% CI [0.05; 1.11]), validated at the protein level (p

Background: This study aimed to explore the expression, molecular mechanism and its biological function of potassium two pore domain channel subfamily K member 1 (KCNK1) in bladder cancer (BC). Methods: We integrated large numbers of external samples (n = 1486) to assess KCNK1 mRNA expression levels and collected in-house samples (n = 245) for immunohistochemistry (IHC) experiments to validate at the KCNK1 protein level. Single-cell RNA sequencing (scRNA-seq) analysis was performed to further assess KCNK1 expression and cellular communication. The transcriptional regulatory mechanisms of KCNK1 expression were explored by ChIP-seq, ATAC-seq and ChIA-PET data. Highly expressed co-expressed genes (HECEGs) of KCNK1 were used to explore potential signalling pathways. Furthermore, the immunoassay, clinical significance and molecular docking of KCNK1 were calculated. Results: KCNK1 mRNA was significantly overexpressed in BC (SMD = 0.58, 95% CI [0.05; 1.11]), validated at the protein level (p < 0.0001). Upregulated KCNK1 mRNA exhibited highly distinguishing ability between BC and control samples (AUC = 0.82 [0.78–0.85]). Further, scRNA-seq analysis revealed that KCNK1 expression was predominantly clustered in BC epithelial cells and tended to increase with cellular differentiation. BC epithelial cells were involved in cellular communication mainly through the MK signalling pathway. Secondly, the KCNK1 transcription start site (TSS) showed promoter-enhancer interactions in three-dimensional space, while being transcriptionally regulated by GRHL2 and FOXA1. Most of the KCNK1 HECEGs were enriched in cell cycle–related signalling pathways. KCNK1 was mainly involved in cellular metabolism–related pathways and regulated cell membrane potassium channel activity. KCNK1 expression was associated with the level of infiltration of various immune cells. Immunotherapy and chemotherapy (docetaxel, paclitaxel and vinblastine) were more effective in BC patients in the high KCNK1 expression group. KCNK1 expression correlated with age, pathology grade and pathologic_M in BC patients. Conclusions: KCNK1 was significantly overexpressed in BC. A complex and sophisticated three-dimensional spatial transcriptional regulatory network existed in the KCNK1 TSS and promoted the upregulated of KCNK1 expression. The high expression of KCNK1 might be involved in the cell cycle, cellular metabolism, and tumour microenvironment through the regulation of potassium channels, and ultimately contributed to the deterioration of BC. [ABSTRACT FROM AUTHOR]

BackgroundPulmonary arterial hypertension (PAH) is a severe and rare disease in the cardiopulmonary system. Its pathogenesis involves vascular remodeling of the pulmonary artery, which results in progressive increases in pulmonary arterial pressure. Chronically increased pulmonary arterial pressure causes right ventricular hypertrophy and subsequent right heart failure. Pulmonary vascular remodeling is attributed to the excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), which are induced by enhanced Ca2+ signaling following the up-/down-regulation of ion channel expression.ObjectivesIn the present study, the functional expression of two-pore domain potassium KCNK channels was investigated in PASMCs from idiopathic PAH (IPAH) patients and experimental pulmonary hypertensive (PH) animals.ResultsIn IPAH-PASMCs, the expression of KCNK1/TWIK1 and KCNK2/TREK1 channels was up-regulated, whereas that of KCNK3/TASK1 and KCNK6/TWIK2 channels was down-regulated. The similar up-regulated expression of KCNK1 and KCNK2 channels was observed in the pulmonary arterial smooth muscles of monocrotaline-induced PH rats, Sugen 5416/hypoxia-induced PH rats, and hypoxia-induced PH mice. The facilitated proliferation of IPAH-PASMCs was suppressed by the KCNK channel blockers, quinine and tetrapentylammonium. The migration of IPAH-PASMCs was also suppressed by these channel blockers. Furthermore, increases in the proliferation and migration were inhibited by the siRNA knockdown of KCNK1 or KCNK2 channels. The siRNA knockdown also caused membrane depolarization and subsequent decrease in cytosolic [Ca2+]. The phosphorylated level of c-Jun N-terminal kinase (JNK) was elevated in IPAH-PASMCs compared to normal-PASMCs. The increased phosphorylation was significantly reduced by the siRNA knockdown of KCNK1 or KCNK2 channels.ConclusionCollectively, these findings indicate that the up-regulated expression of KCNK1 and KCNK2 channels facilitates the proliferation and migration of PASMCs via enhanced Ca2+ signaling and JNK signaling pathway, which is associated with vascular remodeling in PAH.

Aims: Nerve injury‐induced maladaptive changes in gene expression in the spinal neurons are essential for neuropathic pain genesis. Circular RNAs (ciRNA) are emerging as key regulators of gene expression. Here, we identified a nervous‐system‐tissues‐specific ciRNA‐Kat6 with conservation in humans and mice. We aimed to investigate whether and how spinal dorsal horn ciRNA‐Kat6b participates in neuropathic pain. Methods: Unilateral sciatic nerve chronic constrictive injury (CCI) surgery was used to prepare the neuropathic pain model. The differentially expressed ciRNAs were obtained by RNA‐Sequencing. The identification of nervous‐system‐tissues specificity of ciRNA‐Kat6b and the measurement of ciRNA‐Kat6b and microRNA‐26a (miRNA‐26a) expression level were carried out by quantitative RT‐PCR. The ciRNA‐Kat6b that targets miRNA‐26a and miRNA‐26a that targets Kcnk1 were predicted by bioinformatics analysis and verified by in vitro luciferase reports test and in vivo experiments including Western‐blot, immunofluorescence, and RNA–RNA immunoprecipitation. The correlation between neuropathic pain and ciRNA‐Kat6b, miRNA‐26a, or Kcnk1 was examined by the hypersensitivity response to heat and mechanical stimulus. Results: Peripheral nerve injury downregulated ciRNA‐Kat6b in the dorsal spinal horn of male mice. Rescuing this downregulation blocked nerve injury‐induced increase of miRNA‐26a, reversed the miRNA‐26a‐triggered decrease of potassium channel Kcnk1, a key neuropathic pain player, in the dorsal horn, and alleviates CCI‐induced pain hypersensitivities. On the contrary, mimicking this downregulation increased the miRNA‐26a level and decreased Kcnk1 in the spinal cord, resulting in neuropathic pain‐like syndrome in naïve mice. Mechanistically, the downregulation of ciRNA‐Kat6b reduced the accounts of miRNA‐26a binding to ciRNA‐Kat6b, and elevated the binding accounts of miRNA‐26a to the 3′ untranslated region of Kcnk1 mRNA and degeneration of Kcnk1 mRNA, triggering in the reduction of KCNK1 protein in the dorsal horn of neuropathic pain mice. Conclusion: The ciRNA‐Kat6b/miRNA‐26a/Kcnk1 pathway in dorsal horn neurons regulates the development and maintenance of neuropathic pain, ciRNA‐Kat6b may be a potential new target for analgesic and treatment strategies. [ABSTRACT FROM AUTHOR]

Small ubiquitin modifier 1 (SUMO1) is shown to regulate K2P1 background channels in the plasma membrane (PM) of live mammalian cells. Confocal microscopy reveals native SUMO1, SAE1, and Ubc9 (the enzymes that activate and conjugate SUMO1) at PM where SUMO1 and expressed human K2P1 are demonstrated to colocalize. Silent K2P1 channels in excised PM patches are activated by SUMO isopeptidase (SENP1) and resilenced by SUMO1. K2P1-Lys274 is crucial: when mutated to Gln, Arg, Glu, Asp, Cys, or Ala, the channels are constitutively active and insensitive to SUMO1 and SENP1. Tandem mass spectrometry confirms conjugation of SUMO1 to the epsilon-amino group of Lys274 in vitro. FRET microscopy shows that assembly of K2P1 and SUMO1 requires Lys274. Single-particle TIRF microscopy shows that wild-type channels in PM have two K2P1 subunits and assemble with two SUMO1 monomers. Although channels engineered with one Lys274 site carry just one SUMO1 they are activated and silenced by SENP1 and SUMO1 like wild-type channels.

Dysregulated potassium (K + ) channels have previously been shown to promote the development and progression of many types of cancers. Meanwhile, K + channels are particularly important in regulating the endocrine and exocrine functions of pancreas. However, the expression pattern and prognostic significance of K + channels in pancreatic ductal adenocarcinoma (PDAC) remain unknown. In this study, by screening a GEO dataset containing 36 microdissected PDAC and matching normal pancreatic tissue samples, four differentially expressed K + channels (KCNJ5, KCNJ16, KCNN4 and KCNK1) were identified in PDAC. by immunohistochemical analysis of pancreatic tissue sections from Pdx1- C re; LSL- K ras G12D/+ mice (KC), Pdx1- C re; LSL- K ras G12D/+ ; LSL-Tr p 53 R172H/+ mice (KPC) and human PDAC tissue microarrays, we found that Ca 2+ -activated K + channel KCNN4 was significantly elevated in pancreatic intraepithelial neoplasia (PanIN) and PDAC epithelia compared with untransformed pancreas tissues. Higher epithelial KCNN4 expression was closely correlated with advanced TNM stages and predicted a poor prognosis in patients with PDAC. Elevated KCNN4 expression was significantly associated with shorter survival in univariable and multivariable analyses. Collectively, the identification of expression pattern of K + channels in PDAC and its precursor PanIN demonstrates the importance of KCNN4 channel during the malignant transformation of PDAC. On the basis of the prognostic signals from two independent cohorts, KCNN4 should be considered as a promising therapeutic target. [ABSTRACT FROM AUTHOR]

The two-pore domain potassium (K + ) channel TWIK-1 (or K 2P 1.1) contributes to background K + conductance in diverse cell types. TWIK-1, encoded by the KCNK1 gene, is present in the human heart with robust expression in the atria, however its physiological significance is unknown. To evaluate the cardiac effects of TWIK-1 deficiency, we studied zebrafish embryos after knockdown of the two KCNK1 orthologues, kcnk1a and kcnk1b . Knockdown of kcnk1a or kcnk1b individually caused bradycardia and atrial dilation (p < 0.001 vs. controls), while ventricular stroke volume was preserved. Combined knockdown of both kcnk1a and kcnk1b resulted in a more severe phenotype, which was partially reversed by co-injection of wild-type human KCNK1 mRNA, but not by a dominant negative variant of human KCNK1 mRNA. To determine whether genetic variants in KCNK1 might cause atrial fibrillation (AF), we sequenced protein-coding regions in two independent cohorts of patients (373 subjects) and identified three non-synonymous variants, p.R171H, p.I198M and p.G236S, that were all located in highly conserved amino acid residues. In transfected mammalian cells, zebrafish and wild-type human TWIK-1 channels had a similar cellular distribution with predominant localization in the endosomal compartment. Two-electrode voltage-clamp experiments using Xenopus oocytes showed that both zebrafish and wild-type human TWIK-1 channels produced K + currents that are sensitive to external K + concentration as well as acidic pH. There were no effects of the three KCNK1 variants on cellular localization, current amplitude or reversal potential at pH 7.4 or pH 6. Our data indicate that TWIK-1 has a highly conserved role in cardiac function and is required for normal heart rate and atrial morphology. Despite the functional importance of TWIK-1 in the atrium, genetic variation in KCNK1 is not a common primary cause of human AF. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignant cancer and is the second most common cause of cancer-related deaths among females worldwide. Thus, it warrants the urgent development of new therapeutic targets and strategies. Potassium channels are aberrantly expressed in various tumors and are related to tumor progression. However, studies on potassium channels in breast cancer remain limited. First, The Cancer Genome Atlas (TCGA) and Gene Set Enrichment Analysis (GSEA) were used to screen the differentially expressed potassium channels in breast cancer. Several other databases were utilized for further data analysis and visualization, including Gene Expression Profiling Interactive Analysis 2 (GEPIA2), Human Protein Atlas (HPA), GeneMANIA, Tumor Immune Estimation Resource 2 (TIMER2), Catalog of Somatic Mutations in Cancer (COSMIC), cBioPortal, and UCSC Xena tool. Besides, cell proliferation was detected by cell counting kit-8 (CCK8) and 5-Ethynyl-20-deoxyuridine (EdU), and cell migration was detected by wound healing and Transwell assays after knocking down KCNK1. Furthermore, the effect of KCNK1 knockdown on the sensitivity of breast cancer cells to paclitaxel was also evaluated. KCNK1 was overexpressed in breast cancer. Higher KCNK1 expression predicted an unfavorable prognosis. Moreover, the abnormal expression of KCNK1 was attributed to promoter hypomethylation of KCNK1 in breast cancer. Besides, cell proliferation and migration were significantly inhibited post-KCNK1 silencing, while KCNK1 knockdown significantly increased breast cancer cell sensitivity to paclitaxel. Taken together, our findings demonstrated that KCNK1 is a potential prognostic biomarker and therapeutic target of breast cancer. Thus, targeting KCNK1 might help synergize with paclitaxel function in breast cancer treatment. [ABSTRACT FROM AUTHOR]

KCNK1, a member of the family of two-pore K+ ion channels, is specifically induced in the livers of male mice after phenobarbital treatment. Here, we have determined the molecular mechanism of this male-specific activation of the Kcnk1 gene and characterized KCNK1 as a phenobarbital-inducible antihyperplasia factor. Upon activation by phenobarbital, nuclear receptor CAR binds the 97-bp response element (−2441/−2345) within the Kcnk1 promoter. This binding is observed in the livers of male mice, but not in the livers of female mice and requires the pituitary gland, because hypophysectomy abrogates it. Hyperplasia further progressed in the livers of Kcnk1−/− male mice compared with those of Kcnk1+/+ males after phenobarbital treatment. Thus, KCNK1 suppresses phenobarbital-induced hyperplasia. These results indicate that phenobarbital treatment induces KCNK1 to elicit a male-specific and growth-suppressing signal. Thus, KCNK1 and Kcnk1−/− mice provide an experimental tool for further investigation into the molecular mechanism of CAR-mediated promotion of the development of hepatocellular carcinoma in mice. [ABSTRACT FROM AUTHOR]

K+ channels in the inner ear regulate the secretion and homeostasis of K+, i.e. the flux of K+ ions required to ensure good mechanosensory transduction. We studied the expression and cellular localization of TWIK-1 and TWIK-2, two-pore-domain K+ channels responsible for background K+ currents. Reverse transcription-polymerase chain reaction showed that TWIK-1 mRNA is present in the vestibular end organs, vestibular ganglion and cochlea. In contrast, the TWIK-2 mRNA was not detected in the inner ear. Immunocytochemical experiments using confocal microscopy showed that TWIK-1 is specifically localized in ‘non-sensory’ cells of the inner ear, in the dark cells of the vestibule and in the strial marginal cells of the cochlea. All of these cell types secrete and regulate the K+ endolymph production and homeostasis. The labeling was strictly limited to the apical membranes of these cells. TWIK-1 was also detected in the cytoplasm of the large neurons of vestibular ganglion and their fibers. The finding that TWIK-1 is specifically distributed in certain areas of the inner ear suggests that this type of K+ channel plays a role in the regulation of K+ homeostasis in dark cells and in strial marginal cells. This role has yet to be identified. [Copyright &y& Elsevier]

KCNK1 (K+ channel, subfamily K, member 1) is a member of the inwardly rectifying K+ channel family, which drives the membrane potential towards the K+ balance potential. Here, we investigated its functional relevance during osteoclast differentiation. KCNK1 was significantly induced during osteoclast differentiation, but its functional overexpression significantly inhibited osteoclast differentiation induced by RANKL (also known as TNFSF11), which was accompanied by the attenuation of the RANKL-induced Ca2+ oscillation, JNK activation and NFATc1 expression. In contrast, KCNK1 knockdown enhanced the RANKL-induced osteoclast differentiation, JNK activation and NFATc1 expression. In conclusion, we suggest that KCNK1 is a negative regulator of osteoclast differentiation; the increase of K+ influx by its functional blockade might inhibit osteoclast differentiation by inhibiting Ca[sup 2+] oscillation and the JNK-NFATc1 signaling axis. Together with the increased attention on the pharmacological possibilities of using channel inhibition in the treatment of osteoclast-related disorders, further understanding of the functional roles and mechanisms of K+ channels underlying osteoclast-related diseases could be helpful in developing relevant therapeutic strategies. [ABSTRACT FROM AUTHOR]