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Normal function of organs and cells is tightly linked to the cytoarchitecture. Control of the cell volume is therefore vital for the organism. A widely established strategy of cells to counteract swelling is the activation of chloride and potassium channels, which leads to a net efflux of salt followed by water – a process termed regulatory volume decrease. Since there is evidence for swelling-dependent chloride channels (IClswell) being activated also during pathological processes, the identification of the molecular entity underlying IClswell is of utmost importance. Several proteins are discussed as the channel forming IClswell, i.e. phospholemman, p-glycoprotein, CLC-3 and ICln. In this review we would like to focus on the properties of ICln, a protein cloned from a m̲adin d̲arby c̲anine K̲idney (MDCK) cell library whose expression in Xenopus laevis oocytes resulted in a nucleotide sensitive outwardly rectifying chloride current closely resembling the biophysical properties of IClswell.

Here we report the first comparative analysis of patient-reported outcomes (PROs) with chimeric antigen receptor T-cell therapy versus standard-of-care (SOC) therapy in second-line relapsed/refractory large B-cell lymphoma (R/R LBCL) from the pivotal randomized phase 3 ZUMA-7 (NCT03391466) study of axicabtagene ciloleucel (axi-cel) versus SOC. PRO instruments were administered at baseline, day 50, day 100, day 150, month 9, and every 3 months from randomization until 24 months or an event-free survival event. The quality of life (QoL) analysis set comprised patients with a baseline and ≥1 follow-up PRO completion. Prespecified hypotheses for QLQ-C30 Physical Functioning, Global Health Status/QoL, and EQ-5D-5L visual analogue scale (VAS) were tested using mixed-effect models with repeated measures. Clinically meaningful changes were defined as 10 points for QLQ-C30 and 7 for EQ-5D-5L VAS. Among 359 patients, 296 (165 axi-cel, 131 SOC) met inclusion criteria for QoL analysis. At day 100, statistically significant and clinically meaningful differences in mean change of scores from baseline were observed favoring axi-cel over SOC for QLQ-C30 Global Health Status/QoL (estimated difference 18.1 [95% CI, 12.3-23.9]), Physical Functioning (13.1 [95% CI, 8.0-18.2]), and EQ-5D-5L VAS (13.7 [95% CI, 8.5-18.8]; P<.0001 for all). At day 150, scores significantly favored axi-cel versus SOC for Global Health Status/QoL (9.8 [95% CI, 2.6-17.0]; P=.0124) and EQ-5D-5L VAS (11.3 [95% CI, 5.4-17.1]; P=.0004). Axi-cel showed clinically meaningful improvements in QoL over SOC. Superior clinical outcomes and favorable patient experience with axi-cel should help inform treatment choices in second-line R/R LBCL.

ICln is an ion channel identified by expression cloning using a cDNA library from Madin-Darby canine kidney cells. In all organisms tested so far, only one transcript for the ICln protein could be identified. Here we show that two splice variants of the ICln ion channel can be found in Caenorhabditis elegans. Moreover, we show that these two splice variants of the ICln channel protein, which we termed IClnN1 and IClnN2, can be functionally reconstituted and tested in an artificial lipid bilayer. In these experiments, the IClnN1-induced currents showed no voltage-dependent inactivation, whereas the IClnN2-induced currents fully inactivated at positive potentials. The molecular entity responsible for the voltage-dependent inactivation of IClnN2 is a cluster of positively charged amino acids encoded by exon 2a, which is absent in IClnN1. Our experiments suggest a mechanism of channel inactivation that is similar to the "ball and chain" model proposed for the Shaker potassium channel, i.e. a cluster of positively charged amino acids hinders ion permeation through the channel by a molecular and voltage-dependent interaction at the inner vestibulum of the pore. This hypothesis is supported by the finding that synthetic peptides with the same amino acid sequence as the positive cluster can transform the IClnN1-induced current to the current observed after reconstitution of IClnN2. Furthermore, we show that the nematode ICln gene is embedded in an operon harboring two additional genes, which we termed Nx and Ny. Co-reconstitution of Nx and IClnN2 and functional analysis of the related currents revealed a functional interaction between the two proteins, as evidenced by the fact that the IClnN2-induced current in the presence of Nx was no longer voltage-sensitive. The experiments described indicate that the genome organization in nematodes allows an effective approach for the identification of functional partner proteins of ion channels.ICln is a protein that was identified by screening a cDNA library from Madin-Darby canine kidney (MDCK) 1 cells in Xenopus laevis oocytes using the two-electrode voltage-clamp technique (1). The expression of ICln in X. laevis oocytes results in an outwardly rectifying ion current that can be blocked by DIDS, 5-nitro-2-(3-phenylpropylamino)benzoic acid, and the addition of nucleotides to the extracellular fluid. The kinetic, selectivity, and pharmacology of the ICln-induced currents resemble those of the anionic currents activated after cell swelling in a variety of cells (2). The activation of these channels permits the exit of ions, which in turn leads to the exit of water, therefore allowing an effective regulatory volume decrease (3). The molecular entity of the regulatory volume decrease-induced "anionic" channels (RVDCs) is still elusive. Our hypothesis that ICln is a candidate for RVDCs is supported by the fact that the selective knockdown of the ICln protein in fibroblasts and epithelial cells leads to a substantial decrease in swellinginduced RVDC activation (4, 5). Furthermore, t...