Treatment with senicapoc, a KCa 3.1 channel blocker, alleviates hypoxaemia in a mouse model of acute respiratory distress syndrome.

BACKGROUND AND PURPOSE: Acute respiratory distress syndrome (ARDS) is characterized by pulmonary oedema and severe hypoxaemia. We investigated whether genetic deficit or blockade of calcium-activated potassium (KCa 3.1) channels would counteract pulmonary oedema and hypoxaemia in ventilator-induced lung injury, an experimental model for ARDS. EXPERIMENTAL APPROACH: KCa 3.1 channel knockout (Kccn4-/- ) mice were exposed to ventilator-induced lung injury. Control mice exposed to ventilator-induced lung injury were treated with the KCa 3.1 channel inhibitor, senicapoc. The outcomes were oxygenation (PaO2 /FiO2 ratio), lung compliance, lung wet-to-dry weight and protein and cytokines in bronchoalveolar lavage fluid (BALF). KEY RESULTS: Ventilator-induced lung injury resulted in lung oedema, decreased lung compliance, a severe drop in PaO2 /FiO2 ratio, increased protein, neutrophils and tumour necrosis factor-alpha (TNF-α) in BALF from wild-type mice compared with Kccn4-/- mice. Pretreatment with senicapoc (10-70 mg·kg-1 ) prevented the reduction in PaO2 /FiO2 ratio, decrease in lung compliance, increased protein and TNF-α. Senicapoc (30 mg·kg-1 ) reduced histopathological lung injury score and neutrophils in BALF. After injurious ventilation, administration of 30 mg·kg-1 senicapoc also improved the PaO2 /FiO2 ratio and reduced lung injury score and neutrophils in the BALF compared with vehicle-treated mice. In human lung epithelial cells, senicapoc decreased TNF-α-induced permeability. CONCLUSIONS AND IMPLICATIONS: Genetic deficiency of KCa 3.1 channels and senicapoc improved the PaO2 /FiO2 ratio and decreased the cytokines after a ventilator-induced lung injury. Moreover, senicapoc directly affects lung epithelial cells and blocks neutrophil infiltration in the injured lung. These findings indicate that blocking KCa 3.1 channels is a potential treatment in ARDS-like disease.

The role of NFκB in spheroid formation of human breast cancer cells cultured on the Random Positioning Machine.

Human MCF-7 breast cancer cells were exposed to a Random Positioning Machine (RPM). After 24 hours (h) the cells grew either adherently within a monolayer (AD) or within multicellular spheroids (MCS). AD and MCS populations were separately harvested, their cellular differences were determined performing qPCR on genes, which were differently expressed in AD and MCS cells. Gene array technology was applied to detect RPM-sensitive genes in MCF-7 cells after 24 h. Furthermore, the capability to form multicellular spheroids in vitro was compared with the intracellular distribution of NF-kappaB (NFκB) p65. NFκB was equally distributed in static control cells, but predominantly localized in the cytoplasm in AD cells and nucleus in MCS cells exposed to the RPM. Gene array analyses revealed a more than 2-fold change of only 23 genes including some whose products are affected by oxygen levels or regulate glycolysis. Significant upregulations of the mRNAs of enzymes degrading heme, of ANXA1, ANXA2, CTGF, CAV2 and ICAM1, as well as of FAS, Casp8, BAX, p53, CYC1 and PARP1 were observed in MCS cells as compared with 1g-control and AD cells. An interaction analysis of 47 investigated genes suggested that HMOX-1 and NFκB variants are activated, when multicellular spheroids are formed.