Expression of Voltage-Gated Potassium Channels in Human and Mouse Colonic Carcinoma

Ousingsawat, Jiraporn; Spitzner, Melanie; Puntheeranurak, Supaporn; Terracciano, Luigi; Tornillo, Luigi; Bubendorf, Lukas; Kunzelmann, Karl; Schreiber, Rainer

doi:10.1158/1078-0432.ccr-06-1940

Cited by 130 publications

(107 citation statements)

References 22 publications

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“…Src kinase may also be up-regulated in fastgrowing T 84 cells and may be responsible for changes in membrane conductance. It will be interesting to examine in subsequent studies the impact of Eag1 and Best1 on cell migration and tissue invasion since we found previously that genomic amplification of Eag1 in human colorectal carcinoma is an independent marker of adverse prognosis (28).…”

Section: Transformation Of Colonic Epithelial Cells Increases Prolifementioning

confidence: 99%

Eag1 and Bestrophin 1 Are Up-regulated in Fast-growing Colonic Cancer Cells

Spitzner¹,

Martins²,

Soria

et al. 2008

Journal of Biological Chemistry

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An increasing number of studies demonstrate proliferative effects of membrane ion channels (1). Voltage-gated K ϩ channels and other types of K ϩ channels are expressed in numerous types of tumors, where they may serve as diagnostic and prognostic markers and potential drug targets (2-4). Eag1 channels are probably necessary for progression through the G 1 phase and G 0 /G 1 transition of the cell cycle (5). A recent study demonstrates the hyperpolarizing effects of Eag1 and other Kv channels on the membrane voltage of T 84 cells, which supports intracellular pH regulation and Ca 2ϩ increase necessary for proliferation (6).Much less is known about the role of Ca 2ϩ -activated Cl Ϫ channels in cell proliferation (7). This may be due to the ongoing controversy regarding the molecular nature of Ca 2ϩ -activated Cl Ϫ channels (8). A family of putative Ca 2ϩ -activated Cl Ϫ channels has been identified that also controls cell-cell adhesion, apoptosis, and the cell cycle. However, the structure and biophysical properties of these channels are poorly understood (9,10 In the present report we demonstrate that both voltage-gated Eag1 K ϩ channels and bestrophin 1 (Best1) Cl Ϫ channels support proliferation of fast-growing T 84 colonic carcinoma cells. The fast-growing T 84 cell clone was obtained through spontaneous transformation of slow-growing T 84 cells. In contrast to slow-growing T 84 cells, transformed cells do not form polarized monolayers and show a remarkable up-regulation of Eag1 and Best1 expression. We demonstrate that both currents are in charge of enhanced cell proliferation. MATERIALS AND METHODSCell Culture and Proliferation Studies-Human colorectal carcinoma epithelial T 84 cells (ATCC, Manassas, VA) were grown in Dulbecco's modified Eagle's medium/Ham's F-12 medium (1:1) supplemented with 10% fetal bovine serum, 2 mM glutamine, 100 units/ml penicillin, and 100 g/ml streptomycin (Invitrogen, Karlsruhe, Germany) at 5% CO 2 and 37°C. Cells were seeded on fibronectin (Invitrogen)/collagen (Cellon)-coated glass coverslips or permeable supports (Snapwell, Costar). Typically these cells grow slowly as polarized monolayers (T 84 -slow). Because of spontaneous transformation, a T 84 cell line was selected that grew remarkably faster (T 84 -fast). For proliferation assays, cells were plated at a density of 2000 cells/ 0.35 cm 2 and incubated 2 days later with either niflumic acid (0.01-100 mM) or astemizole (0.5-5000 nM). Cell proliferation was assessed by 5-bromo-2Ј-deoxyuridine (BrdUrd) 3 incorporation using an enzyme-linked immunosorbent assay kit (Roche Diagnostics, Penzberg, Germany) and cell counting. The cell number was assessed after fixation in 3.7% formaldehyde and 0.5% Triton X-100 for 30 min at room temperature and after staining with Mayer's hemalaun (Merck, Darmstadt, Germany) for 5 min. Digitized microscopic images were taken (Fluovert FS, Leitz), and nuclei were counted using imaging software (TINA version 2.09g). Toxicity of the blockers was * This work was supported by Deutsche Forschungsgemei...

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Section: Transformation Of Colonic Epithelial Cells Increases Prolifementioning

confidence: 99%

Eag1 and Bestrophin 1 Are Up-regulated in Fast-growing Colonic Cancer Cells

Spitzner¹,

Martins²,

Soria

et al. 2008

Journal of Biological Chemistry

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“…We conducted an in-depth analysis regarding the potential effects of rapamycin on oncogenic ion channels. Indeed, a substantial body of evidence exists for the oncogenic function of voltage-gated (Kv) and Ca 2 þ -activated (BK) K þ channels in colonic cancer and other tumors (Yao and Kwan, 1999;Pardo et al, 1999;Pardo et al, 2005;Ousingsawat et al, 2007;Ousingsawat et al, 2008). K þ channels control proliferation by controlling cell cycle and essential homeostatic parameters, such as intracellular Ca 2 þ , pH and cell volume (Schreiber, 2005).…”

mentioning

confidence: 99%

Rapamycin inhibits oncogenic intestinal ion channels and neoplasia in APCMin/+ mice

et al. 2009

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The adenomatous polyposis coli (APC) gene is mutated in familial adenomatous polyposis. Mice with a heterozygous APC Min mutation develop multiple intestinal neoplasia (Min) leading to premature death. Early in colorectal carcinogenesis, APC Min/ þ mice show enhanced Akt-mammalian target of rapamycin (mTOR) signaling, which is paralleled by upregulation of oncogenic K þ channels. In this study, we tested the effect of mTOR inhibition with rapamycin on tumor formation in APC Min/ þ mice and evaluated ion channel regulation. We found that continuous long-term rapamycin treatment of APC Min/ þ mice dramatically inhibits intestinal neoplasia. Moreover, although untreated APC Min/ þ mice lose weight, experience intestinal bleeding and succumb to multiple neoplasia by 22.3±1.4 weeks of age, mice treated with rapamycin maintain stable weight and survive long term (39.6 ± 3.4 weeks), with more than 30% surviving >1 year. Impressively, abnormalities in colonic electrolyte transport typical for APC Min/ þ mice are abolished, along with the suppression of epithelial Na þ channel (ENaC) and oncogenic K þ ion channels BK, Elk1 and Erg1, both functionally and at mRNA levels. These results show that continuous prophylaxis by rapamycin markedly inhibits the development of APC mutation-related polyposis, and suggest a novel contributing mechanism of action through the blockade of intestinal oncogenic ion channels.

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“…Eag1 displays oncogenic properties and shows a very restricted distribution in normal tissues (Pardo et al, 1999;Hemmerlein et al, 2006) but it is expressed in many types of tumors including cervical, breast, lung, prostate, liver and colon carcinoma (Farías et al, 2004;Hemmerlein et al, 2006;Ousingsawat et al, 2007). Inhibition of either channel activity or expression leads to decreased tumor cell proliferation both in vitro and in vivo (Pardo et al, 1999;Gómez-Varela et al, 2007;Ousingsawat et al, 2007). The restricted distribution of Eag1 and its role in proliferation have converted this ion channel in an attractive tool for diagnose and therapy of many cancers.…”

Section: Potassium Channelsmentioning

confidence: 99%

“…Thus, Eag is a promising tumor marker. On the other hand, inhibition of either channel activity or expression decreases proliferation of tumor cells both in vitro and in vivo (Pardo et al, 1999;Ousingsawat et al, 2007;Gómez-Varela et al 2007;Downie et al, 2008;Díaz et al, 2009). Therefore, Eag is also a promising therapeutic target for many types of cancer (Camacho, 2006;.…”

Section: Oncogenic Eag1 K + Channels In Cervical Cancer and Regulatiomentioning

confidence: 99%

The Human Papilloma Virus – Ion Channel Link in Cancer: An Alternative Opportunity for Diagnosis and Therapy

Ramírez¹,

Camacho²

2012

Human Papillomavirus and Related Diseases - From Bench to Bedside - Research Aspects

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Expression of Voltage-Gated Potassium Channels in Human and Mouse Colonic Carcinoma

Cited by 130 publications

References 22 publications

Eag1 and Bestrophin 1 Are Up-regulated in Fast-growing Colonic Cancer Cells

Eag1 and Bestrophin 1 Are Up-regulated in Fast-growing Colonic Cancer Cells

Rapamycin inhibits oncogenic intestinal ion channels and neoplasia in APCMin/+ mice

The Human Papilloma Virus – Ion Channel Link in Cancer: An Alternative Opportunity for Diagnosis and Therapy

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