Search

Glutathione S-transferases P1 (GSTP1) is a phase II detoxifying enzyme and increased expression of GSTP1 has been linked with acquired resistance to anti-cancer drugs. However, most anticancer drugs are not good substrates for GSTP1, suggesting that the contribution of GSTP1 to drug resistances might not be dependent on its capacity to detoxify chemicals or drugs. In the current study, we found a novel mechanism by which GSTP1 protects human breast cancer cells from adriamycin (ADR)-induced cell death and contributes to the drug resistance. GSTP1 protein level is very low in human breast cancer cell line MCF-7 but is high in ADR-resistant MCF-7/ADR cells. Under ADR treatment, MCF-7/ADR cells showed a higher autophagy level than MCF-7 cells. Overexpression of GSTP1 in MCF-7 cells by using the DNA transfection vector enhanced autophagy and down-regulation of GSTP1 through RNA interference in MCF-7/ADR cells decreased autophagy. When autophagy was prevented, GSTP1-induced ADR resistance reduced. We found that GSTP1 enhanced autophagy level in MCF-7 cells through interacting with p110α subunit of phosphatidylinositol-3-kinase (PI3K) and then inhibited PI3K/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) activity. Proline123, leucine160, and glutamine163, which located in C terminal of GSTP1, are essential for GSTP1 to interact with p110α, and the following autophagy and drug resistance regulation. Taken together, our findings demonstrate that high level of GSTP1 maintains resistance of breast cancer cells to ADR through promoting autophagy. These new molecular insights provide an important contribution to our better understanding the effect of GSTP1 on the resistance of tumors to chemotherapy.

The tumor-associated inflammatory microenvironment plays a pivotal role in human non-small cell lung cancer (NSCLC) development. FGFR1 and TLR4 involve in the regulation of inflammatory microenvironment of NSCLC.However, the relationship between the FGFR1 and TLR4 signaling and the mechanisms that involved in tumor-associated microenvironment are still unclear. We investigated the expression of FGFR1 and TLR4 in cancerous tissues and noncancerous lung tissues from 60 primary NSCLC patients using immunohistochemical staining. Three cell lines (A549, PC-9 and SK-MES-1) were used for in vitro studies. We demonstrated that the expression of FGFR1 and TLR4 was significantly correlated (r=0.504, p

Fructose 1, 6-diphosphate (FDP), a glycolytic intermediate，has been identified to possess antioxidant activities. Here we show the protective effect of FDP against alcohol-induced liver injury in mice and the underlying mechanisms. The in vivo experiments demonstrated that FDP, orally administered to mice, dose-dependently suppressed alcohol (50%, v/v, 12ml/kg)-induced increase of serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), serum triglyceride (TG) level and hepatic malondialdehyde (MDA) level. FDP also inhibited liver histological lesions induced by seven-day administration of alcohol to mice. In vitro study indicated that FDP inhibited ethanol-induced L02 cell apoptosis via reducing pro-caspase3 protein level and increasing poly ADP-ribose polymerase (PARP) cleavage. The mechanism analysis showed that FDP prevented ethanol-induced decrease of mouse antioxidant capability through inhibiting the reducion of the level of glutathione (GSH) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-PX) in mouse livers, and suppressing the reducion of GSH level and SOD activity in L02 cells. FDP also enhanced alcohol metabolic rate through increasing alcohol dehydrogenase (ADH) activity and acetaldehyde dehydrogenase (ALDH) protein level, and down-regulating cytochrome p450 2E1 (CYP2E1). These results displayed that FDP protected mice from alcohol-induced liver injury, suggesting the potential activity of FDP in preventing alcoholic liver disease (ALD).

Background In our previous studies, we have indentified that 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) can alleviate toluene diisocyanate-induced airway epithelial barrier disruption and we also found that vascular endothelial growth factor (VEGF) derived from airway epithelials cells could disrupt epithelial barrier. Objective The study aimed to investigate whether 1,25(OH) 2 D 3 can inhibit house dust mite (HDM) induced airway epithelial barrier dysfunction by regulating the VEGF pathway. Method The 16HBE and BEAS-2B cells were cultured and treated according to the experiment requirement. Trans Epithelial Electric Resistance (TEER), permeability of epithelial layer, and distribution and expression of junction proteins were used to evaluate the cell layer barrier function, Western Blot was used to evaluate the expression of junction proteins and phosphorylated Akt in the cells, RT-PCR and ELISA were used to evaluate the VEGF gene expression and protein release in the cells. Recombinant VEGF165 was used to determine the role of the VEGF pathway in the epithelial barrier function. Results HDM resulted in a decline in TEER and increase of cell permeability, following abnormal distribution and expression of junction proteins (E-Cadherin and zona occludens (ZO)-1), accompanied by a significant upregulation of VEGF and phosphorylated Akt, which were all partly recovered by treatment with either 1,25(OH) 2 D 3 or PI3K inhibitor LY294002. VEGF165-induced barrier dysfunction was accompanied by disruption of the epithelial E-cadherin and β-catenin, pretreatment of 1,25(OH) 2 D 3 and LY294002 markedly attenuated VEGF-induced airway barrier disruption in 16HBE cells. Conclusion 1,25(OH) 2 D 3 can alleviate HDM-induced airway epithelial barrier dysfunction by inhibiting PI3K pathway-dependent VEGF release.

In this study, cinnamic acid derivatives with pyridine ring were synthesized via Hantzsch reaction in order to expand conjugation system and their antioxidant abilities were tested. According to the evaluation results of their antioxidant properties, compounds 2 and 3 have similar antioxidant activity to prevent DNA from •OH– and Cu2+/GSH induced oxidation, demonstrating that 1,4-dihydropyridine and pyridine nucleus exhibit good resistance to oxidation while the substituents have little effect. In the meantime, the AAPH-induced oxidative DNA damage [AAPH=2,2′-azobis(2-methylpropionamidine)dihydrochloride] and trapping ABTS+• test show that N—H bond and large conjugation systems are the pivotal parts to improve the activities of antioxidant.

Cancer stem-like cells (CSCs) have been reported to play major roles in tumorigenesis, tumor relapse, and metastasis after therapy against colorectal carcinoma (CRC). Therefore, identification of colorectal CSC regulators could provide promising targets for CRC. Ligand-of-Numb protein X1 (LNX1) is one E3 ubiquitin ligase which mediates the ubiquitination and degradation of Numb. Although several studies indicate LNX1 could be a potential suppressor of cancer diseases, the functions of LNX1 in mediating cancer stemness remain poorly understood. In this study, LNX1 was identified as a negative regulator of cancer stemness in CRC, which was downregulated in colonospheres or side population (SP) cells. Furthermore, the coxsackievirus and adenovirus receptor (CXADR) was found to be one critical downstream mediator of cancer stemness regulated by LNX1. Interestingly, the anti-breast cancer drug tamoxifen was found to be an agonist of LNX1 and suppress cancer stemness in CRC. In sum, this study provided the evidences that LNX1 signaling plays important roles in regulating the stemness of colon cancer cells.