ABSTRACT
The aim of our study was to conduct a meta-analysis to assess whether combined evidence shows associations between C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and genetic susceptibility to rheumatoid arthritis (RA). A total of 11 articles involving 20 comparisons were included, containing 12 comparisons for the MTHFR C677T polymorphism and 8 comparisons for the MTHFR A1298C polymorphism. Significant evidence was detected for the association of RA susceptibility with the MTHFR C677T polymorphism T allele under allelic contrast and dominant model in Asians (T versus C, OR = 1.300, 95 % CI = 1.104-1.531, p = 0.002; TT + CT versus CC, OR = 1.495, 95 % CI = 1.187-1.882, p = 0.001). Significant association between RA susceptibility and the MTHFR A1298C polymorphism A allele under recessive model was found in the overall meta-analysis (AA versus AC + CC, OR = 1.281, 95 % CI = 1.048-1.565, p = 0.016). Our meta-analysis results demonstrate that the MTHFR C677T polymorphism is involved in the genetic susceptibility of RA in Asians, and the MTHFR A1298C polymorphism is associated with genetic susceptibility to RA in the overall population. Given the paucity of studies, especially in non-Asian populations, further studies with larger sample sizes are required to elucidate the role of MTHFR polymorphisms in the genetic basis of RA in different ethnic populations.
Subject(s)
Arthritis, Rheumatoid/genetics , Genetic Predisposition to Disease , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Polymorphism, Genetic , Alleles , Arthritis, Rheumatoid/ethnology , Asian People , Genotype , Humans , Odds Ratio , Polymorphism, Single Nucleotide , Risk FactorsABSTRACT
α-eleostearic acid (α-ESA) has been shown to possess antitumor activity in cancer cells. However, the underlying mechanism(s) remain largely unknown. The present study was designed to investigate the antitumor effect of α-ESA in breast cancer cells showing different expression levels of the human epidermal growth factor receptor 2 (HER2). α-ESA inhibited cell growth and induced apoptosis in the SKBR3 and T47D breast cancer cell lines. The mechanism by which cell growth was inhibited involved G0/G1 and G2/M cell cycle phase arrest. The MTT assay showed that SKBR3 cells are more sensitive to α-ESA compared to T47D cells. Western blot analysis revealed that α-ESA treatment not only reduced HER2/HER3 protein expression, but also increased the level of phosphorylated phosphatase and tensin homolog protein (PTEN), which led to decreased levels of phosphorylated Akt. Inactive Akt further reduced phosphorylation of glycogen synthase kinase-3ß (GSK-3ß) and B-cell lymphoma 2 (Bcl-2)associated death promoter (BAD) proteins. Furthermore, the level of the anti-apoptotic protein Bcl-2 was found to be reduced following α-ESA treatment. Notably, nuclear factor κB (NF-κB) was activated by α-ESA treatment. Data of the present study showed that the antitumor activity of α-ESA is at least partly mediated by reduction of the HER2/HER3 heterodimer protein level, activation of the Akt/BAD/Bcl-2 apoptotic pathway and inhibition of the Akt/GSK-3ß survival pathway in the two breast cancer cell lines investigated in this study. Therefore, α-ESA may be considered a beneficial dietary factor for the prevention and treatment of invasive breast cancer in cells overexpressing HER2.
Subject(s)
Apoptosis/drug effects , Breast Neoplasms/physiopathology , Linolenic Acids/pharmacology , Receptor, ErbB-2/metabolism , Receptor, ErbB-3/metabolism , Signal Transduction/drug effects , Antineoplastic Agents/pharmacology , Breast Neoplasms/metabolism , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Female , Glycogen Synthase Kinase 3/metabolism , Glycogen Synthase Kinase 3 beta , Humans , PTEN Phosphohydrolase/metabolism , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , bcl-Associated Death Protein/metabolismABSTRACT
PI-103, the first synthetic multitargeted compound which simultaneously inhibits PI3Kalpha and mammalian target of rapamycin (mTOR) shows high antitumor activity in glioma xenografts. In the present study, clear antitumor activity was observed with PI-103 treatment in two gefitinib-resistant non-small cell lung cancer (NSCLC) cell lines, A549 and H460, by simultaneously inhibiting p70s6k phosporylation and Akt phosphorylation in response to mTOR inhibition. In addition, H460 cells with activating mutations of PIK3CA were more sensitive to PI-103 than A549 cells with wild-type PIK3CA. PI-103 was found to inhibit growth by causing G0-G1 arrest in A549 and H460 cells. Western blotting showed that PI-103 induced down-regulation of cyclin D1 and E1 and simultaneously up-regulated p21 and p27, associated with arrest in the G0-G1 phase of the cell cycle. Furthermore, p53, the tumor suppressor which transcriptionally regulates p21, was also upregulated with PI-103 treatment. Collectively, our results suggest that multitargeted intervention is the most effective tumor therapy, and the cooperative blockade of PI3Kalpha and mTOR with PI-103 shows promise for treating gefitinib-resistant NSCLC.
