The ion transporter NKCC1 determines brain tumor cell migration by regulating the interplay between cell adhesion and growth factor signaling, and is a potential therapeutic target to treat brain cancer.

(TAS2Rs) were found in the lung and act to relax airway smooth muscle (ASM) via intracellular Ca 2ϩ concentration signaling generated from restricted phospholipase C activation. As potential therapy, TAS2R agonists could be add-on treatment when patients fail to achieve adequate bronchodilation with chronic ␤-agonists. The ␤2-adrenergic receptor (␤2AR) of ASM undergoes extensive functional desensitization. It remains unknown whether this desensitization affects TAS2R function, by cross talk at the receptors or distal common components in the relaxation machinery. We studied intracellular signaling and cell mechanics using isolated human ASM, mouse tracheal responses, and human bronchial responses to characterize TAS2R relaxation in the context of ␤ 2AR desensitization. In isolated human ASM, magnetic twisting cytometry revealed Ͼ90% loss of isoproterenol-promoted decrease in cell stiffness after 18-h exposure to albuterol. Under these same conditions of ␤ 2AR desensitization, the TAS2R agonist chloroquine relaxation response was unaffected. TAS2R-mediated stimulation of intracellular Ca 2ϩ concentration in human ASM was unaltered by albuterol pretreatment, in contrast to cAMP signaling, which was desensitized by Ͼ90%. In mouse trachea, ␤ 2AR desensitization by ␤-agonist amounted to 92 Ϯ 6.0% (P Ͻ 0.001), while, under these same conditions, TAS2R desensitization was not significant (11 Ϯ 3.5%). In human lung slices, chronic ␤-agonist exposure culminated in 64 Ϯ 5.7% (P Ͻ 0.001) desensitization of ␤ 2AR-mediated dilation of carbachol-constricted airways that was reversed by chloroquine. We conclude that there is no evidence for physiologically relevant cross-desensitization of TAS2R-mediated ASM relaxation from chronic ␤-agonist treatment. These findings portend a favorable therapeutic profile for TAS2R agonists for the treatment of bronchospasm in asthma or chronic obstructive lung disease.

Drug resistance is a major limitation to the successful treatment of advanced prostate cancer (PCa). Patients who have metastatic, castration-resistant PCa (mCRPC) are treated with chemotherapeutics. However, these standard therapy modalities culminate in the development of resistance. We established paclitaxel resistance in a classic, androgen-insensitive mCRPC cell line (DU145) and, using a suite of molecular and biophysical methods, characterized the structural and functional changes in vitro and in vivo that are associated with the development of drug resistance. After acquiring paclitaxel-resistance, cells exhibited an abnormal nuclear morphology with extensive chromosomal content, an increase in stiffness, and faster cytoskeletal remodeling dynamics. Compared with the parental DU145, paclitaxel-resistant (DU145-TxR) cells became highly invasive and motile in vitro, exercised greater cell traction forces, and formed larger and rapidly growing tumors in mouse xenografts. Furthermore, DU145-TxR cells showed a discrete loss of keratins but a distinct gain of ZEB1, Vimentin and Snail, suggesting an epithelial-to-mesenchymal transition. These findings demonstrate, for the first time, that paclitaxel resistance in PCa is associated with a trans-differentiation of epithelial cell machinery that enables more aggressive and invasive phenotype and portend new strategies for developing novel biomarkers and effective treatment modalities for PCa patients.

Here we explored the impact of hydrogen sulfide (H2S) on biophysical properties of the primary human airway smooth muscle (ASM)–the end effector of acute airway narrowing in asthma. Using Magnetic Twisting Cytometry (MTC), we measured dynamic changes in the stiffness of isolated ASM, at the single-cell level, in response to varying doses of GYY4137 (1–10 mM). GYY4137 slowly released appreciable levels of H2S in the range of 10–275 µM, and H2S released was long lived. In isolated human ASM cells, GYY4137 acutely decreased stiffness (i.e. an indicator of the single-cell relaxation) in a dose-dependent fashion, and stiffness decreases were sustained in culture for 24h. Human ASM cells showed protein expressions of cystathionine-γ-lyase (CSE; a H2S synthesizing enzyme) and ATP-sensitive potassium (KATP) channels. The KATP channel opener pinacidil effectively relaxed isolated ASM cells. In addition, pinacidil-induced ASM relaxation was completely inhibited by the treatment of cells with the KATP channel blocker glibenclamide. Glibenclamide also markedly attenuated GYY4137-mediated relaxation of isolated human ASM cells. Taken together, our findings demonstrate that H2S causes the relaxation of human ASM and implicate as well the role for sarcolemmal KATP channels. Finally, given that ASM cells express intrinsic enzymatic machinery of generating H2S, we suggest thereby this class of gasotransmitter can be further exploited for potential therapy against obstructive lung disease.