Effects of low-dose hydroxychloroquine on expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in peri-infarct myocardium in rats.

BACKGROUND: Low-dose hydroxychloroquine (HCQ) and ataxia-telangiectasia-mutated (ATM) protein kinase have recently been postulated to be beneficial for the prevention of the age-associated metabolic syndrome including hypertension, hypercholesterolemia and glucose intolerance; however, the effects of low-dose HCQ on the expression of ATM downstream phosphorylated Akt (protein kinase B) and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium remain unclear. OBJECTIVE: To explore the effects of low-dose HCQ on the expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium in a rat model. METHODS: Myocardial infarction (MI) was induced experimentally in a subset of rats, while others underwent sham operation (sham). Three days after operation, surviving Sprague-Dawley male rats were divided into MI+HCQ, MI, sham+HCQ and sham groups. MI+HCQ and sham + HCQ groups were treated with HCQ (3.4 mg/kg); and MI and sham groups were treated with phosphate buffered (ie, physiological) saline (10 mL/kg) by gavage every day for 12 weeks. The expression of phosphorylated Akt and p53 proteins and cardiomyocyte apoptosis in the peri-infarct myocardium was detected by Western blot and terminal deoxynucleotidyl transferase dUTP nick end labelling, respectively. RESULTS: Twelve weeks after treatment, the expression of phosphorylated Akt protein was significantly increased (P<0.05). Expression of phosphorylated p53 protein was not significantly different (P>0.05) in the peri-infarct myocardium of the MI+HCQ group from that in the MI group. The cardiomyocyte apoptosis rate in the peri-infarct myocardium was significantly decreased in the MI+HCQ group compared with the MI group (P<0.05). CONCLUSION: Low-dose HCQ can significantly increase the expression of phosphorylated Akt protein without significantly impacting expression of phosphorylated p53 protein in the peri-infarct myocardium. Accordingly, it can inhibit cardiomyocyte apoptosis in the peri-infarct myocardium.

Dominant negative epidermal growth factor receptor inhibits growth of human gastric cancer cells by inducing cell cycle arrest and apoptosis.

Epidermal growth factor receptor (EGFR) promotes proliferation of cancer cells. Dominant negative EGFR (DNEGFR) can block EGFR signal pathway by competing with endogenous EGFR for ligands. However, whether EGFR is overexpressed in gastric cancer and whether DNEGFR contributes to the inhibition of gastric cancer growth are not known. In this study, with the methods of immunohistochemistry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry, Terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick-end labeling assay and western blotting; we demonstrate that EGFR is expressed in 29 of 60 of human gastric cancer. In addition, DNEGFR induces G0/G1 arrest by decreasing expression of phosphorylated retinoblastoma protein, phosphorylated GSK-3ß, cyclin D1, and by increasing expression of p21 and p27 in human gastric cancer cell lines SGC-7901 and NCI-N87. Finally, DNEGFR induces apoptosis in these cells. Our results indicate that DNFGFR may provide promising treatment strategy for a subgroup of human gastric cancers that express EGFR.

Fucoidan prevents multiple myeloma cell escape from chemotherapy-induced drug cytotoxicity.

Minimal residual disease (MRD) occurrence with some chemotherapy drugs that promote tumor cell escape is also a key factor in blood malignancy relapse. We observed that cytarabine promotes multiple myeloma (MM) cell escape and that the number of cells in the lower chamber increased with increasing clinical disease stage in in vitro model which was constructed by a Boyden chamber, matrigel glue and serum from MM patients in different disease stages. The mechanism of cytarabine that promotes MM cell escape is closely associated with the up-regulation of CXCR4. SDF-1α can up-regulate the expression of MMP9 and RHoC proteins in MM cells with up-regulated CXCR4, and further promote the cell escape. Fucoidan, a sulfated polysaccharide in the cell wall matrix of brown algae, has attracted much attention for its multiple biological activities, and we further explored the effects and possible underlying mechanisms of fucoidan on MM cell escape from cytarabine cytotoxicity. The results show that fucoidan may decrease MM cell escape from cytarabine cytotoxicity, and that fucoidan can down-regulate CXCR4, MMP9 and RHoC expression. This research provides new direction for investigating MRD occurrence and prevention.

[Clinical significance of MRP8 and cypA expression in laryngeal squamous cell carcinoma tissues].

OBJECTIVE: To study differential expression of MRP8, CypA protein in the patients of laryngeal squamous cell carcinoma (LSCC) and the relationship in the development of LSCC. METHOD: Immunohistochemistry was used to detect the expression of MRP8,CypA protein in LSCC tissues of 41 cases and matched paraneoplastic normal tissues of 41 cases,with results compared to the clinical data to determine significance. RESULT: The expression of MRP8, CypA protein in carcinoma and normal tissues and composition of different positive grades were in statistical significance (P < 0.01). The expression levels of MRP8 were no significant correlations were identified against any parameter (age,sex and cervical lymphatic metastasis) examined (P > 0.05), but related to pathological stage (P < 0.05). CONCLUSION: MRP8 protein is on intimate terms with different pathological differentiation stage of LSCC. MRP8, CypA protein may play an important role in the development and progression of LSCC.

Inhibitory effects of cytoplasmic-domain substituted epidermal growth factor receptor on growth, invasion and angiogenesis in human gastric cancer cells.

Epidermal growth factor receptor (EGFR) blockade is a promising therapeutic approach for gastric cancer overexpressing EGFR. EGFR, with a cytoplasmic domain substituted by enhanced green fluorescent protein (DNEGFR-EGFP), can act as a dominant negative mutant receptor to block the EGFR signaling pathway by competing with endogenous EGFR for ligands. The aim of this study was to investigate the effects of DNEGFR-EGFP on the growth, invasion and angiogenesis of human gastric cancer cells, and to elucidate the possible mechanisms behind them. Using multiple cellular and molecular approaches such as gene transfection, MTT, flow cytometry, Western blotting, ELISA, invasion and angiogenesis assays, we found that DNEGFR-EGFP led to G0/G1 arrest by down-regulating cyclin D1 and CDK2 and up-regulating p27, and repressed the invasion and angiogenesis of SGC-7901 cells by inhibiting them from secreting MMP-2, MMP-9 and VEGF. These results indicate that the EGFR blockade strategy (termed dominant negative strategy targeting EGFR) may serve as a promising therapy for the treatment of EGFR-overexpressed gastric cancer.