[show abstract][hide abstract] ABSTRACT: Akt/protein kinase B is a pivotal component downstream of phosphatidylinositol 3-kinase (PI3K) pathway, whose activity regulates the balance between cell survival and apoptosis. Phosphorylation of Akt occurs at two key sites either at Thr308 site in the activation loop or at Ser473 site in the hydrophobic motif. The phosphorylated form of Akt (pAkt) is activated to promote cell survival. The mechanisms of pAkt dephosphorylation and how the signal transduction of Akt pathway is terminated are still largely unknown. In this study, we identified a novel protein phosphatase CSTP1(complete s transactivated protein 1), which interacts and dephosphorylates Akt specifically at Ser473 site in vivo and in vitro, blocks cell cycle progression and promotes cell apoptosis. The effects of CSTP1 on cell survival and cell cycle were abrogated by depletion of phosphatase domain of CSTP1 or by expression of a constitutively active form of Akt (S473D), suggesting Ser473 site of Akt as a primary cellular target of CSTP1. Expression profile analysis showed that CSTP1 expression is selectively down-regulated in non-invasive bladder cancer tissues and over-expression of CSTP1 suppressed the size of tumors in nude mice. Kaplan-Meier curves revealed that decreased expression of CSTP1 implicated significantly reduced recurrence-free survival in patients suffered from non-invasive bladder cancers.
PLoS ONE 01/2013; 8(6):e65679. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Candida albicans is a human commensal that is also responsible for chronic gastritis and peptic ulcerous disease. Little is known about the genetic profiles of the C. albicans strains in the digestive tract of dyspeptic patients. The aim of this study was to evaluate the prevalence, diversity, and genetic profiles among C. albicans isolates recovered from natural colonization of the digestive tract in the dyspeptic patients.
Oral swab samples (n = 111) and gastric mucosa samples (n = 102) were obtained from a group of patients who presented dyspeptic symptoms or ulcer complaints. Oral swab samples (n = 162) were also obtained from healthy volunteers. C. albicans isolates were characterized and analyzed by multilocus sequence typing. The prevalence of Candida spp. in the oral samples was not significantly different between the dyspeptic group and the healthy group (36.0%, 40/111 vs. 29.6%, 48/162; P > 0.05). However, there were significant differences between the groups in the distribution of species isolated and the genotypes of the C. albicans isolates. C. albicans was isolated from 97.8% of the Candida-positive subjects in the dyspeptic group, but from only 56.3% in the healthy group (P < 0.001). DST1593 was the dominant C. albicans genotype from the digestive tract of the dyspeptic group (60%, 27/45), but not the healthy group (14.8%, 4/27) (P < 0.001).
Our data suggest a possible link between particular C. albicans strain genotypes and the host microenvironment. Positivity for particular C. albicans genotypes could signify susceptibility to dyspepsia.
PLoS ONE 01/2012; 7(4):e35311. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study compared tankyrase 1 expression and autophagy quantity between erectile dysfunction (ED) and non-ED rats' corpus cavernosum smooth muscle cells (CSMCs). This study aslo explored the effect and possible mechanism of tankyrase 1 on autophagy and cell proliferation in ageing ED rats' CSMCs. The intracavernous pressure and mean systemic arterial pressure were measured to investigate erectile function so that eight 24-month-old ED and eight 8-month-old male Wistar rats were chosen respectively. The rat CSMCs were isolated and cultured by enzyme digestion, in which tankyrase 1 expression and autophagy quantity were compared. Tankyrase 1 overexpression was induced with plasmid transfection by Lipofectamine. The effect of tankyrase 1 overexpression on proliferation, autophagy and mTOR pathway in 24-month-old ED rats' CSMCs was measured by the cell growth curve in MTT assay, cell cycle analysis in flow cytometry (FCM), key protein expression in Western blot, autophagy quantity in transmission electron microscopy, monodansylcadaverine staining and GFP-LC3 fluorescence. The primary CSMCs were confirmed by immunofluorescence, and the purity was 99.1% in FCM. Compared with that of 8-month-old rats, tankyrase 1 expression and autophagy quantity significantly decreased in 24-month-old ED rats' primary CSMCs (P < 0.01). Tankyrase 1 overexpression significantly increased the growth rate (P < 0.05) and increased the S phase of cell cycle (P < 0.01). The autophagosome quantity was remarkably increased (P < 0.01), LC3-I/II and Beclin 1 were upregulated (P < 0.01 and P < 0.05), and p-p70S6K (Thr(389)) was downregulated in 24-month-old ED rat CSMCs (P < 0.05). In conclusion, Tankyrase 1 and autophagy decrease in the CSMCs from aging rats with ED, and tankyrase 1 may have a positive effect on proliferation by enhancing autophagy and regulating the mTOR signalling pathway.
Asian Journal of Andrology 09/2010; 12(5):744-52. · 2.14 Impact Factor