High expression of KCa3.1 in patients with clear cell renal carcinoma predicts high metastatic risk and poor survival

Rabjerg, M. ; Oliván-Viguera, A. ; Hansen, L.K. ; Jensen, L. ; Sevelsted-Møller, L. ; Walter, S. ; Jensen, B.L. ; Marcussen, N. ; Köhler, R.

Resumen: 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.

Methodology/Principal Findings
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/Significance
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.

Idioma: Inglés

DOI: 10.1371/journal.pone.0122992

Año: 2015

Publicado en: PloS one 10, 4 (2015), e0122992[24 pp]
ISSN: 1932-6203

Factor impacto JCR: 3.057 (2015)

Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 11 / 62 = 0.177 (2015) - Q1 - T1

Factor impacto SCIMAGO: 1.427 - Agricultural and Biological Sciences (miscellaneous) (Q1) - Medicine (miscellaneous) (Q1) - Biochemistry, Genetics and Molecular Biology (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/GIPASC-B105
Financiación: info:eu-repo/grantAgreement/EC/FP7/321721/EU/Identification and validation of cerebral KCa3.1/KCa2.3 potassium channels a drug tragets for the prevention and treatment of cerebral ischemia associated with diabetes and Alzheimers disease/BRAINIK
Financiación: info:eu-repo/grantAgreement/ES/ISCIII/RD12-0042-0014

Tipo y forma: Artículo (Versión definitiva)