GlyH-101 and CaCCinh-A01 Inhibited HT-29 Proliferation by Activating the Mitochondrial Apoptosis Pathway and Arresting the Cell Cycle.

BACKGROUND/AIM: GlyH-101 and CaCCinh-A01 are effective blockers of cystic fibrosis transmembrane conductance regulator (CFTR) and Ca2+-activated chloride channels (CaCCs), respectively. Available evidence suggests that GlyH-101 and CaCCinh-A01 can suppress cell proliferation, block invasion and metastasis, and cause several cancer cell types to undergo apoptosis, demonstrating their anti-tumor properties. The aim of this study was to investigate the effect of GlyH-101 and CaCCinh-A01 on HT-29 cell activity and to suggest the possible molecular mechanisms by which inhibitors of CFTR and CaCCs inhibit HT-29 cell activity. MATERIALS AND METHODS: Human colon HT-29 cancer cells were treated with GlyH-101 or CaCCinh-A01 or GlyH-101 plus CaCCinh-A01 complex. Cell viability was determined by MTT assay, the apoptosis and cell cycle were determined by flow cytometry, and reactive oxygen species (ROS) leves were determined by 2',7'-Dichlorodihydrofluorescein diacetate staining. The expression of proteins related to apoptosis and cell cycle regulation was measured by western blotting. RESULTS: The proliferative ability of HT-29 cells was dose- and time-dependently reduced by GlyH-101 and CaCCinh-A01. Treatment with GlyH-101 and CaCCinh-A01 resulted in cell necrosis and apoptosis, up-regulated ROS levels, activated the mitochondrial apoptosis pathway, prompted arrest of the cell cycle in S phase, and increased the levels of proteins related to the cell cycle. Additionally, the combination of these two inhibitors had a stronger regulatory effect on HT-29 cell proliferation than either GlyH-101 or CaCCinh-A01 treated alone. CONCLUSION: GlyH-101 and CaCCinh-A01 inhibited cell proliferation through cell cycle arrest and mitochondrial-related pathways in vitro. The combination of these inhibitors could further enhance their anti-proliferative effects. Our findings propose new lead compounds with anti-colon cancer activity, and also provide new evidence for the effectiveness of chloride channels-targeted therapy in anticancer therapy.

A Novel Paclitaxel-Loaded Polymeric Micelle System with Favorable Biocompatibility and Superior Antitumor Activity.

BACKGROUND/AIM: Polymeric micelles are promising vehicles for paclitaxel delivery. Further improvement in the stability of the micelle formulation is desirable. MATERIALS AND METHODS: Monomethoxy poly(ethylene glycol)-block-poly(D,L-lactide)-9-fluorenylmethoxycarbonyl-L-phenylalanine (mPEG-PDLLA-Phe(Fmoc)) was synthesized through a classical esterification reaction. Paclitaxel-loaded mPEG-PDLLA-Phe(Fmoc) micelles (PTX-PheMs) were prepared by the self-assembly method. Composition, structure and physicochemical properties were characterized. Pharmacokinetics were evaluated in rats. Therapeutic effect was evaluated in tumor-bearing mice. Safety profile was assessed by a hemolysis assay and an acute-toxicity study. RESULTS: The average size of PTX-PheMs was about 45 nm. The hemolysis and acute-toxicity tests confirmed its biocompatibility and safety. The pharmacokinetics and therapeutic effect experiments demonstrated its long circulation property and superior antitumor effect. CONCLUSION: mPEG-PDLLA-Phe(Fmoc) micelle is a biocompatible and effective drug delivery system for hydrophobic drugs such as PTX.

CFTR chloride channel is a molecular target of the natural cancer preventive agent resveratrol.

The naturally occurring polyphenol compound resveratrol (RES) has been receiving wide attention because of its variety of health benefits and favourable biological activities. Previous studies have shown that RES could induce intestinal chloride secretion in mouse jejunum and stimulate cAMP-dependent Cl- secretion in T84, primary cultured murine nasal septal and human sinonasal epithelial cells, but the precise molecular target is not clear. We therefore tested the hypothesis that RES may stimulate the activity of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Using cell-based fluorescent assays, transepithelial short-circuit current measurements and excised inside-out patch-clamp analysis; we found that RES dose-dependently potentiate CFTR Cl- channel activities, which was reversed by CFTR inhibitors CFTR(inh)-172 and GlyH101. Transepithelial Cl- secretion by CFTR-expressing FRT cells was stimulated by RES with half maximal concentration -80 microM. Intracellular cAMP content was not elevated by RES in FRT cells. Excised inside-out patch-clamp analysis indicated that RES significantly increased the chloride currents of CFTR. In ex vivo studies, RES stimulated the transmucosal chloride current of rat colon by short-circuit current assay. These data suggested that CFTR is a molecular target of RES. Our findings add a new molecular target to RES, and RES may represent a novel class of therapeutic lead compounds in treating CFTR-related diseases including CF and habitual constipation.

Maintenance of bone mass in patients receiving dialytic therapy.

To determine what factors contribute to and change bone mineral density (BMD) in dialysis patients, serial lumbar spine dual x-ray absorptiometry studies were analyzed by stepwise regression analysis in 67 black dialysis patients. The patients were 50.5 +/- 2.0 years of age (mean +/- SE) and 49% were men; the patients had received dialytic therapy for 3.7 +/- 0.5 years. The mean initial BMD z-score was 0.147 +/- 0.182. By cross-sectional analysis, the BMD increased in the male and premenopausal female patients but decreased in the postmenopausal female patients by 2.5% g/cm2/decade of life, less than that observed in black patients with normal renal function. Univariate analysis and stepwise regression analysis demonstrated radiographic evidence of osteopenia (beta-coefficient = -0.180 +/- 0.050; P = 0.001) and prior parathyroidectomy (beta-coefficient = 0.133 +/- 0.070; P = 0.054) as the only variables significantly correlated to the BMD. The effects of biochemical variables and different treatments on the delta BMD, calculated as the difference between each patient's first and second BMDs divided by the interval in years, were evaluated by stepwise regression analysis in 41 patients. The mean interval between the two BMDs was 18.4 +/- 1.02 months (range, 5 to 34 months) and the delta BMD was 0.025 +/- 0.018 g/cm2/yr, increasing in 65% of the patients. By univariate and stepwise regression analysis, the mean monthly serum total alkaline phosphatase concentration was the only variable that correlated with the delta BMD (beta-coefficient = 0.0001; P = 0.030).(ABSTRACT TRUNCATED AT 250 WORDS)