Sirt1 inhibits kidney stones formation by attenuating calcium oxalate-induced cell injury.

Cell injury is a necessary and critical event during CaOx kidney stone formation. Sirt1 exerts a number of pleiotropic effects, protecting against renal cell injury. This study aims to explore the relationship between Sirt1 and CaOx kidney stone formation and the underlying mechanism. Sirt1 expression in renal tissues or HK-2 cells was detected by Western blot, immunohistochemistry and immunofluorescence. Apoptosis in renal tissues was examined by TUNEL staining. Renal pathological changes and the crystals deposition were detected by hematoxylin-eosin and Von Kossa staining. Crystal-cell adhesion and cell injury in HK-2 cells were assessed by atomic absorption spectrometry and flow cytometry, respectively. Sirt1 expression in nephrolithiasis patients was downregulated and the level of apoptosis was increased. Further study found that Sirt1 expression was decreased in both in vivo and in vitro models. Interestingly, the levels of cell injury were elevated in vivo and in vitro models. Suppressing Sirt1 expression promoted COM-induced crystal-cell adhesion and exacerbated cell injury. In contrast, increasing the expression of Sirt1 by lentivirus transfection in vitro and resveratrol administration in vivo, alleviated crystal deposition and cell damage. Our findings suggest that Sirt1 could inhibit kidney stone formation, at least in part, through attenuating CaOx -induced cell injury.

Melatonin Inhibits Migration and Invasion in LPS-Stimulated and -Unstimulated Prostate Cancer Cells Through Blocking Multiple EMT-Relative Pathways.

PURPOSE: Gram-negative bacteria are usually found in prostate cancer (PCa) tissues. This study aims to investigate the role of lipopolysaccharide (LPS), a glycolipid compound found in the outer membrane of gram-negative bacteria, on the migration and invasion of PCa cells, and to evaluate the protective effect of melatonin. MATERIALS AND METHODS: DU145, PC-3 and LNCaP cells were incubated with LPS in the presence or absence of melatonin. Wound healing and Transwell assays were used to analyze migration and invasion of PCa cells. RT-PCR and Western blotting were used to assess the mRNA and protein levels, respectively. Co-IP was used to analyze ß-catenin ubiquitination. RESULTS: Our results showed that LPS promoted migration and invasion of PCa cells. In addition, LPS stimulated inflammatory reaction and induced epithelial-mesenchymal transition (EMT) in PCa cells by activating several TLR4 downstream pathways. Specifically, LPS promoted NF-κB/IL-6/STAT3 signal transduction. In addition, LPS upregulated phosphorylation levels of cytoplasmic AKTSer473 and GSK-3ßSer9. Moreover, LPS induced phosphorylation of GSK-3ßSer9 in the "disruption complex", and then inhibited phosphorylation and ubiquitination of cytoplasmic ß-catenin, leading to ß-catenin nuclear translocation. Interestingly, melatonin inhibited invasion and migration not only in LPS-stimulated but also in LPS-unstimulated PCa cells. Melatonin suppressed PCa cells migration and invasion by blocking EMT mediated by IL-6/STAT3, AKT/GSK-3ß and ß-catenin pathways. CONCLUSION: This study provides evidence that melatonin inhibits migration and invasion through blocking multiple TLR4 downstream EMT-associated pathways both in LPS-stimulated and -unstimulated PCa cells. Our results provide new insights into the role of bacterial infection in PCa metastasis and a potential therapeutic agent.

ROS-mediated genotoxic stress is involved in NaAsO2-induced cell cycle arrest, stemness enhancement and chemoresistance of prostate cancer cells in a p53-independent manner.

Several epidemiological studies reported that chronic arsenic exposure increased risk of prostate cancer. This study aimed to investigate whether chronic NaAsO2 exposure elevates stemness and chemoresistance in prostate cancer cells. DU145 (wild-type p53) and PC-3 (p53-null) cells were exposed to NaAsO2 (2 µmol/L) for 30 generations. IC50s to docetaxel and cisplatin were increased in NaAsO2-exposed DU145 and PC-3 cells. The number of tumor spheres was elevated in NaAsO2-exposed DU145 and PC-3 cells. Nanog, SOX-2 and ALDH1A1, three markers of cancer stemness, were upregulated in NaAsO2-exposed PC-3 spheres. Moreover, NaAsO2-exposed DU145 and PC-3 cells were arrested in G2/M phase. Histone H2AX phosphorylation on Ser139, an indicator for DNA double-strand break, was upregulated in NaAsO2-exposed DU145 and PC-3 cells. ATM phosphorylation on Ser1981, a key sensor of genotoxic stress, was rapidly elevated in NaAsO2-exposed DU145 cells. Phosphor-p53, a downstream molecule of ATM signaling, and p21, a direct target of p53, were upregulated in NaAsO2-exposed DU145 cells. Unexpectedly, p21 was also elevated in NaAsO2-exposed p53-null PC-3 cells. Antioxidant NAC alleviated NaAsO2-induced ATM phosphorylation, cell cycle arrest, and subsequent stemness enhancement and chemoresistance in both DU145 and PC-3 cells. These results suggest that ROS-mediated genotoxic stress is involved in NaAsO2-induced cell cycle arrest, stemness enhancement and chemoresistance of prostate cancer cells in a p53-independent manner.

Calcitriol inhibits lipopolysaccharide-induced proliferation, migration and invasion of prostate cancer cells through suppressing STAT3 signal activation.

Increasing evidence suggests that infection promotes the initiation and progression of prostate cancer. This study investigated the effects of lipopolysaccharide (LPS), a major component of Gram-negative bacilli, on proliferation, migration and invasion of prostate cancer cells and the protective effects of 1α,25(OH)2D3 (calcitriol). PC-3 and DU145 cells were stimulated with LPS (2.0 µg/mL) in the presence or absence of 1α,25(OH)2D3 (100 nM). Our results shown that 1α,25(OH)2D3 reduced the proportion of S phase cells in LPS-stimulated PC-3 and DU145 cells, and down-regulated the nuclear protein levels of Cyclin D1 and PCNA in LPS-stimulated PC-3 cells. In addition, 1α,25(OH)2D3 inhibited migration and invasion, as determined by wound healing and transwell assay, in LPS-stimulated PC-3 and DU145 cells. Of interest, we observed that 1α,25(OH)2D3 inhibits NF-κB activation and subsequent synthesis and secretion of IL-6 and IL-8 by promoting VDR and NF-κB p65 interaction. Surprisingly, 1α,25(OH)2D3 blocks nuclear translocation of pSTAT3 by promoting physical interaction between VDR and pSTAT3 (Tyr705) in LPS-stimulated PC-3 and DU145 cells. These results suggest that 1α,25(OH)2D3 inhibits LPS-induced proliferation, migration and invasion in prostate cancer cells by directly and indirectly blocking STAT3 signal transduction.