BackgroundCa2+-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 FindingsWe 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/SignificanceOur 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.
BackgroundThe calmodulin/calcium-activated K+ channel KCa3.1 is expressed in red and white blood cells, epithelia and endothelia, and possibly central and peripheral neurons. However, our knowledge about its contribution to neurological functions and behavior is incomplete. Here, we investigated whether genetic deficiency or pharmacological activation of KCa3.1 change behavior and cerebral monoamine levels in mice.Methodology/Principal FindingsIn the open field test, KCa3.1-deficiency increased horizontal activity, as KCa3.1−/− mice travelled longer distances (≈145% of KCa3.1+/+) and at higher speed (≈1.5-fold of KCa3.1+/+). Working memory in the Y-maze was reduced by KCa3.1-deficiency. Motor coordination on the rotarod and neuromuscular functions were unchanged. In KCa3.1−/− mice, HPLC analysis revealed that turn-over rates of serotonin were reduced in frontal cortex, striatum and brain stem, while noradrenalin turn-over rates were increased in the frontal cortex. Dopamine turn-over rates were unaltered. Plasma catecholamine and corticosterone levels were unaltered. Intraperitoneal injections of 10 mg/kg of the KCa3.1/KCa2-activator SKA-31 reduced rearing and turning behavior in KCa3.1+/+ but not in KCa3.1−/− mice, while 30 mg/kg SKA-31 caused strong sedation in 50% of the animals of either genotypes. KCa3.1−/− mice were hyperactive (≈+60%) in their home cage and SKA-31-administration reduced nocturnal physical activity in KCa3.1+/+ but not in KCa3.1−/− mice.Conclusions/SignificanceKCa3.1-deficiency causes locomotor hyperactivity and altered monoamine levels in selected brain regions, suggesting a so far unknown functional link of KCa3.1 channels to behavior and monoaminergic neurotransmission in mice. The tranquilizing effects of low-dose SKA-31 raise the possibility to use KCa3.1/KCa2 channels as novel pharmacological targets for the treatment of neuropsychiatric hyperactivity disorders.
The prognosis associated with clear cell renal carcinoma (ccRCC) can vary widely and novel molecular prognostic markers are needed to assess prognosis at an earlier stage. Several gene products have been investigated for this purpose, but none of them have been implemented in clinical practice. Here we hypothesized that we, using TaqMan® Array, could identify superior prognostic messenger RNA (mRNA)s in long-term follow-up. Messenger RNA level of 19 candidate genes was investigated in 97 patients with ccRCC. Three genes impacted significantly on prognosis in both univariate and multivariate analysis. In univariate analysis, CSNK2A1 was a strong indicator of a poor overall survival (OS) (HR = 5.01, p< 0.001), disease specific survival (DSS) (HR = 6.21, p = 0.007) and progression free survival (PFS) (HR = 5.93, p = 0.005). High expression of SPP1 was associated to poor PFS (HR = 4.41, p = 0.04). DEFB1 was associated with a better PFS (HR = 0.24, p = 0.006). In multivariate analysis, CSNK2A1 was associated to a worse OS (HR = 3.56, p = 0.008) and PFS (HR = 3.84, p = 0.005), whereas SPP1 was an independent predictor of a worse PFS (HR = 3.46, p = 0.007) and DEFB1 of a better PFS (HR = 0.37, p = 0.027). These results show that with TaqMan®) Array we could identify three superior gene products related to prognosis. Further studies are needed to elucidate the pathways and roles of these genes in renal cacer development.
On the basis of associations between tumor size, pathological stage, histological subtype and tumor grade in incidentally detected renal cell carcinoma vs symptomatic renal cell carcinoma, we discussed the need for a screening program of renal cell carcinoma in Denmark. We analyzed a consecutive series of 204 patients with renal tumors in 2011 and 2012. The tumors were classified according to detection mode: symptomatic and incidental and compared to pathological parameters. Eighty-nine patients (44%) were symptomatic, 113 (55%) were incidental. Information was not available in two patients. In the incidental group, the size (p<0.05), pathological stage (p<0.001), Fuhrman grading (p<0.0001) and Leibovich score (p<0.0001) were lower than in those causing symptoms. Significantly less in the incidental group had metastasis at follow-up (p<0.0001). Incidentally discovered RCC constitute a major part of kidney tumors. They have a more favorable prognosis than symptomatic tumors and seem to be discovered in an earlier phase. Needle core biopsy is an accurate technique for distinguishing between malignant and benign tumors and is recommendable for smaller incidental tumors. Screening may help detect RCC at an earlier stage.
Background and aims Potassium channels, KV1.3 and KCa3.1, have been suggested to control T-cell activation, proliferation, and cytokine production and may thus constitute targets for anti-inflammatory therapy. Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by excessive T-cell infiltration and cytokine production. It is unknown if KV1.3 and KCa3.1 in the inflamed mucosa are markers of active UC. We hypothesized that KV1.3 and KCa3.1 correlate with disease activity and cytokine production in patients with UC. Methods Mucosal biopsies were collected from patients with active UC (n = 33) and controls (n = 15). Protein and mRNA expression of KV1.3 and KCa3.1, immune cell markers, and pro-inflammatory cytokines were determined by quantitative-real-time-polymerase-chain-reaction (qPCR) and immunofluorescence, and correlated with clinical parameters of inflammation. In-vitro cytokine production was measured in human CD3+ T-cells after pharmacological blockade of KV1.3 and KCa3.1. Results Active UC KV1.3 mRNA expression was increased 5-fold compared to controls. Immunofluorescence analyses revealed that KV1.3 protein was present in inflamed mucosa in 57% of CD4+ and 23% of CD8+ T-cells. KV1.3 was virtually absent on infiltrating macrophages. KV1.3 mRNA expression correlated significantly with mRNA expression of pro-inflammatory cytokines TNF-α (R2 = 0.61) and IL-17A (R2 = 0.51), the mayo endoscopic subscore (R2 = 0.13), and histological inflammation (R2 = 0.23). In-vitro blockade of T-cell KV1.3 and KCa3.1 decreased production of IFN-γ, TNF-α, and IL-17A. Conclusions High levels of KV1.3 in CD4 and CD8 positive T-cells infiltrates are associated with production of pro-inflammatory IL-17A and TNF-α in active UC. KV1.3 may serve as a marker of disease activity and pharmacological blockade might constitute a novel immunosuppressive strategy.
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