title: High expression of KCa3.1 in patients with clear cell renal carcinoma predicts high metastatic risk and poor survival.
abstract: BACKGROUND
  Ca2+-activated K+ channels have been implicated in cancer cell growth, metastasis, and tumor angiogenesis. Here we hypothesized that high mRNA and protein expression of the intermediate-conductance Ca2+-activated K+ channel, KCa3.1, is a molecular marker of clear cell Renal Cell Carcinoma (ccRCC) and metastatic potential and survival.
  
  
  RESULTS
  We analyzed channel expression by qRT-PCR, immunohistochemistry, and patch-clamp in ccRCC and benign oncocytoma specimens, in primary ccRCC and oncocytoma cell lines, as well as in two ccRCC cell lines (Caki-1 and Caki-2). CcRCC specimens contained 12-fold higher mRNA levels of KCa3.1 than oncocytoma specimens. The large-conductance channel, KCa1.1, was 3-fold more highly expressed in ccRCC than in oncocytoma. KCa3.1 mRNA expression in ccRCC was 2-fold higher than in the healthy cortex of the same kidney. Disease specific survival trended towards reduction in the subgroup of high-KCa3.1-expressing tumors (p<0.08 vs. low-KCa3.1-expressing tumors). Progression-free survival (time to metastasis/recurrence) was reduced significantly in the subgroup of high-KCa3.1-expressing tumors (p<0.02, vs. low-KCa3.1-expressing tumors). Immunohistochemistry revealed high protein expression of KCa3.1 in tumor vessels of ccRCC and oncocytoma and in a subset of ccRCC cells. Oncocytoma cells were devoid of KCa3.1 protein. In a primary ccRCC cell line and Caki-1/2-ccRCC cells, we found KCa3.1-protein as well as TRAM-34-sensitive KCa3.1-currents in a subset of cells. Furthermore, Caki-1/2-ccRCC cells displayed functional Paxilline-sensitive KCa1.1 currents. Neither KCa3.1 nor KCa1.1 were found in a primary oncocytoma cell line. Yet KCa-blockers, like TRAM-34 (KCa3.1) and Paxilline (KCa1.1), had no appreciable effects on Caki-1 proliferation in-vitro.
  
  
  CONCLUSIONS
  Our study demonstrated expression of KCa3.1 in ccRCC but not in benign oncocytoma. Moreover, high KCa3.1-mRNA expression levels were indicative of low disease specific survival of ccRCC patients, short progression-free survival, and a high metastatic potential. Therefore, KCa3.1 is of prognostic value in ccRCC.
authors.affiliation: Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark.
authors.forename: Maj
authors.initials: M
authors.lastname: Rabjerg
authors.affiliation: Aragon Institute of Health Sciences I+CS/IIS, 50009 Zaragoza, Spain.
authors.forename: Aida
authors.initials: A
authors.lastname: Oliván-Viguera
authors.affiliation: Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark.
authors.forename: Lars Koch
authors.initials: LK
authors.lastname: Hansen
authors.affiliation: Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark.
authors.forename: Line
authors.initials: L
authors.lastname: Jensen
authors.affiliation: Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark.
authors.forename: Linda
authors.initials: L
authors.lastname: Sevelsted-Møller
authors.affiliation: Department of Urology, Odense University Hospital, DK-5000 Odense C, Denmark.
authors.forename: Steen
authors.initials: S
authors.lastname: Walter
authors.affiliation: Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark.
authors.forename: Boye L
authors.initials: BL
authors.lastname: Jensen
authors.affiliation: Department of Pathology, Odense University Hospital, DK-5000 Odense C, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Marcussen
authors.affiliation: Aragon Institute of Health Sciences I+CS/IIS, 50009 Zaragoza, Spain; Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), 50009 Zaragoza, Spain.
authors.forename: Ralf
authors.initials: R
authors.lastname: Köhler
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D045744:Cell Line, Tumor; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000096:biosynthesis*; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D015996:Survival Rate
chemical_list: D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; C496923:KCNN4 protein, human; D009363:Neoplasm Proteins
references.citation: Diagn Mol Pathol. 2011 Dec;20(4):212-7
references.pmid: 22089348
references.citation: Arterioscler Thromb Vasc Biol. 2014 Jan;34(1):127-35
references.pmid: 24177326
references.citation: Biochem J. 2004 Feb 1;377(Pt 3):569-78
references.pmid: 14565846
references.citation: J Physiol. 2007 Sep 1;583(Pt 2):705-17
references.pmid: 17584847
references.citation: Neuropharmacology. 1996;35(7):903-14
references.pmid: 8938721
references.citation: Circulation. 2003 Sep 2;108(9):1119-25
references.pmid: 12939222
references.citation: Expert Rev Clin Pharmacol. 2010 May;3(3):385-96
references.pmid: 22111618
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14518-23
references.pmid: 19706538
references.citation: Nat Rev Cancer. 2014 Jan;14(1):39-48
references.pmid: 24336491
references.citation: Oncogene. 2009 Apr 16;28(15):1792-806
references.pmid: 19270724
references.citation: J Biol Chem. 2001 Apr 13;276(15):12249-56
references.pmid: 11278890
references.citation: Philos Trans R Soc Lond B Biol Sci. 2014 Mar 19;369(1638):20130101
references.pmid: 24493749
references.citation: PLoS One. 2012;7(10):e47825
references.pmid: 23110108
references.citation: Neuron. 2001 Oct 11;32(1):13-23
references.pmid: 11604135
references.citation: PLoS One. 2013;8(3):e58614
references.pmid: 23516517
references.citation: Pharmacol Rev. 2005 Dec;57(4):463-72
references.pmid: 16382103
references.citation: Genome Biol. 2002 Jun 18;3(7):RESEARCH0034
references.pmid: 12184808
references.citation: Curr Med Chem. 2007;14(13):1437-57
references.pmid: 17584055
references.citation: Curr Med Chem. 2012;19(5):627-46
references.pmid: 22204337
references.citation: J Natl Cancer Inst. 1994 Jun 1;86(11):829-35
references.pmid: 8182763
references.citation: Mol Pharmacol. 2004 Mar;65(3):630-8
references.pmid: 14978241
references.citation: Oncogene. 2007 Aug 2;26(35):5107-14
references.pmid: 17310992
references.citation: Annu Rev Immunol. 2001;19:497-521
references.pmid: 11244045
references.citation: J Anat. 2006 Feb;208(2):219-29
references.pmid: 16441566
references.citation: Circ Res. 2003 Nov 14;93(10):965-71
references.pmid: 14551242
references.citation: BMC Syst Biol. 2010;4:51
references.pmid: 20420713
references.citation: Proc Natl Acad Sci U S A. 1997 Oct 14;94(21):11651-6
references.pmid: 9326665
references.citation: Genome Biol. 2006;7(10):R100
references.pmid: 17076895
references.citation: Am J Physiol Cell Physiol. 2011 Sep;301(3):C541-9
references.pmid: 21543740
references.citation: J Med Chem. 2007 Feb 8;50(3):528-42
references.pmid: 17266205
references.citation: Br J Pharmacol. 2006 Aug;148(7):909-17
references.pmid: 16770324
references.citation: Am J Physiol Cell Physiol. 2012 Nov 15;303(10):C1070-8
references.pmid: 22992678
references.citation: PLoS One. 2012;7(8):e41664
references.pmid: 22899999
references.citation: J Clin Invest. 2003 Sep;112(5):717-24
references.pmid: 12952920
references.citation: J Huazhong Univ Sci Technolog Med Sci. 2013 Feb;33(1):86-9
references.pmid: 23392713
references.citation: Cell Death Dis. 2013;4:e773
references.pmid: 23949222
references.citation: Curr Med Chem. 2012;19(5):697-713
references.pmid: 22204342
references.citation: PLoS One. 2010;5(8):e12304
references.pmid: 20808839
references.citation: J Physiol. 1992 Jan;445:537-48
references.pmid: 1323670
references.citation: Transplantation. 2013 Jan 27;95(2):285-92
references.pmid: 23325003
references.citation: J Neurosci. 1992 Jan;12(1):297-305
references.pmid: 1370323
references.citation: Eur J Pharmacol. 2003 Jun 27;471(3):157-64
references.pmid: 12826234
references.citation: Arterioscler Thromb Vasc Biol. 2005 Apr;25(4):704-9
references.pmid: 15662023
references.citation: Nucleic Acids Res. 2001 May 1;29(9):e45
references.pmid: 11328886
references.citation: Glia. 2014 Jun;62(6):971-81
references.pmid: 24585442
references.citation: Am J Physiol Cell Physiol. 2004 Jul;287(1):C125-34
references.pmid: 14985237
references.citation: Biochem Biophys Res Commun. 2004 Mar 26;316(1):244-51
references.pmid: 15003537
references.citation: Circ Res. 2000 Sep 15;87(6):496-503
references.pmid: 10988242
references.citation: Semin Nephrol. 2013 May;33(3):215-28
references.pmid: 23953799
references.citation: Arterioscler Thromb Vasc Biol. 2008 Jun;28(6):1084-9
references.pmid: 18309114
references.citation: Arch Pathol Lab Med. 2007 Dec;131(12):1782-8
references.pmid: 18081436
references.citation: Proc Natl Acad Sci U S A. 1980 Apr;77(4):2200-4
references.pmid: 6929546
references.citation: Eur Urol. 2011 Oct;60(4):615-21
references.pmid: 21741761
references.citation: Neuroreport. 2002 Mar 25;13(4):403-7
references.pmid: 11930149
references.citation: Gen Pharmacol. 1995 Dec;26(8):1643-9
references.pmid: 8745151
references.citation: Prostate. 1997 Oct 1;33(2):112-22
references.pmid: 9316652
references.citation: Curr Opin Nephrol Hypertens. 2007 Sep;16(5):430-6
references.pmid: 17693758
references.citation: Oncogene. 2007 Apr 12;26(17):2525-34
references.pmid: 17146446
references.citation: Transplant Proc. 2009 Jul-Aug;41(6):2601-6
references.pmid: 19715983
references.citation: PLoS One. 2012;7(10):e47744
references.pmid: 23077667
references.citation: Cancer Res. 2013 Aug 1;73(15):4852-61
references.pmid: 23774210
references.citation: Trends Pharmacol Sci. 2004 May;25(5):280-9
references.pmid: 15120495
references.citation: Neuron. 1994 Dec;13(6):1315-30
references.pmid: 7993625
references.citation: Proc Natl Acad Sci U S A. 2000 Jul 5;97(14):8151-6
references.pmid: 10884437
references.citation: J Membr Biol. 1996 Nov;154(2):91-107
references.pmid: 8929284
references.citation: Histol Histopathol. 2010 Oct;25(10):1247-55
references.pmid: 20712009
references.citation: Genome Biol. 2007;8(2):R19
references.pmid: 17291332
references.citation: PLoS One. 2013;8(10):e76740
references.pmid: 24146918
references.citation: J Biol Chem. 2000 Nov 24;275(47):37137-49
references.pmid: 10961988
references.citation: Pflugers Arch. 2010 May;459(6):969-76
references.pmid: 20349244
references.citation: J Biol Chem. 1999 May 21;274(21):14838-49
references.pmid: 10329683
references.citation: Am J Physiol Cell Physiol. 2000 Dec;279(6):C1751-9
references.pmid: 11078689