Xiaoqun Dong

Angiotensin II type 1 receptor antagonists inhibit cell proliferation and angiogenesis in breast cancer.

Angiotensin II type 1 receptor (AT1R) promotes tumor invasion, migration, metastasis and angiogenesis. We explored the potential antitumor effects of AT1R antagonists in breast cancer. We found that angiotensin II promoted cell proliferation and upregulated the expression of vascular endothelial growth factor A (VEGF-A) in MCF-7 cells. Losartan downregulated the expression of VEGF-A in MCF-7 cells treated with angiotensin II. Candesartan downregulated the expression of VEGF-A in mice bearing MCF-7 xenografts and inhibited tumor growth and angiogenesis. AT1R and VEGF-A expression correlated with increased microvascular density in 102 breast cancer patients. Our data suggest that AT1R antagonists might be useful to suppress breast cancer by inhibiting the angiotensin II.

Antioxidant genes, diabetes and dietary antioxidants in association with risk of pancreatic cancer.

To test the hypothesis that polymorphic variants of antioxidant genes modify the risk of pancreatic cancer, we examined seven single-nucleotide polymorphisms (SNPs) of genes coding for superoxide dismutase (SOD) 2, glutathione S-transferase alpha 4 (GSTA4), catalase and glutathione peroxidase in 575 patients with pancreatic adenocarcinoma and 648 healthy controls in a case-control study. Information on risk factors was collected by personal interview and dietary information was collected by a self-administered food frequency questionnaire. Genotypes were determined using the Taqman method. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were estimated by unconditional logistic regression. No significant main effect of genotype was observed. A borderline significant interaction between diabetes and SOD2 Ex2+24T>C CT/TT genotype was observed (P(interaction) = 0.051); the AORs (95% CI) were 0.98 (0.73-1.32) for non-diabetics carrying the CT/TT genotype, 1.73 (0.94-3.18) for diabetics carrying the CC genotype and 3.49 (2.22-5.49) for diabetics carrying the CT/TT genotype compared with non-diabetics carrying the CC genotype. Moreover, the SOD2 -1221G>A AA genotype carriers had a significantly increased risk for pancreatic cancer among those with a low dietary vitamin E intake but decreased risk among those with a high vitamin E intake (P(interaction) = 0.002). There was a non-significant interaction between diabetes and GSTA4 Ex5-64G>A genotypes (P(interaction) = 0.078). No significant interaction between genotype with cigarette smoking or vitamin C intake was observed. These data suggest that genetic variations in antioxidant defenses modify the risk of pancreatic cancer in diabetics or individuals with a low dietary vitamin E intake.

Biomarkers of TGF-β signaling pathway and prognosis of pancreatic cancer

Background Transforming growth factor (TGF)-β signaling pathway, may act both as a tumor suppressor and as a tumor promoter in pancreatic cancer, depending on tumor stage and cellular context. TGF-β pathway has been under intensive investigation as a potential therapeutic target in the treatment of cancer. We hypothesized a correlation between TGF-βR2/SMAD4 expression in the tumor, plasma TGF-β1 ligand level, genetic variation in TGF-B pathway and prognosis of pancreatic cancer. Method We examined TGF-βR2 and SMAD4 protein expression in biopsy or surgical samples from 91 patients with pancreatic ductal adenocarcinoma (PDAC) using immunohistochemistry. Plasma level of TGF-β1 was measured in 644 patients with PDAC using ELISA. Twenty-eight single nucleotide polymorphisms (SNP) of the TGF-β1, TGF-β2, TGF-β3, TGF-βR1, TGF-βR2, and SMAD4 genes were determined in 1636 patients with PDAC using the Sequenom method. Correlation between protein expression in the tumor, plasma TGF-β1 level, and genotypes with overall survival (OS) was evaluated with Cox proportional regression models. Results The expression level of TGF-βR2 and SMAD4 as an independent marker was not associated with OS. However, patients with both low nuclear staining of TGF-βR2 and high nuclear staining of SMAD4 may have better survival (P = 0.06). The mean and median level of TGF-β1 was 15.44 (SD: 10.99) and 12.61 (interquartile range: 8.31 to 19.04) ng/ml respectively. Patients with advanced disease and in the upper quartile range of TGF-β1 level had significantly reduced survival than those with low levels (P = 0.02). A significant association of SMAD4 SNP rs113545983 with overall survival was observed (P<0.0001). Conclusion Our data provides valuable baseline information regarding the TGF-β pathway in pancreatic cancer, which can be utilized in targeted therapy clinical trials. High TGF-β1 plasma level, SMAD4 SNP or TGF-βR2/SMAD4 tumor protein expression may suggest a dependence on this pathway in patients with advanced pancreatic cancer.

Prognostic values of osteopontin-c, E-cadherin and β-catenin in breast cancer

OBJECTIVE To determine the correlation of cell adhesion molecules (osteopontin-c, E-cadherin and β-catenin) with clinicopathological characteristics in breast cancer. METHODS Immunostaining of osteopontin-c, E-cadherin and β-catenin were conducted in 170 samples of breast cancer and 30 samples of adjacent normal breast tissues. The correlation of osteopontin-c, E-cadherin and β-catenin expression level with clinicopathological characteristics was evaluated by Pearsons chi-square and Wilcoxon rank-sum test. Univariate and multivariate Cox hazard regression model was used to assess the prognostic values of osteopontin-c, E-cadherin and β-catenin in clinical outcome of breast cancer. RESULTS A higher level of osteopontin-c whereas lower levels of E-cadherin and β-catenin were observed in breast cancer as compared with the normal breast tissues. The expression of osteopontin-c was negatively associated with the expression of E-cadherin and β-catenin. The expression of osteopontin-c correlated with lymph node metastasis, and advanced TNM stage and histologic grade. The expression of E-cadherin correlated with low histologic grade; and β-catenin with low TNM stage and histological grade. Moreover, high osteopontin-c level correlated with tumor recurrence or metastasis as well as triple negative subtype. The expression of osteopontin-c was an independent prognostic factor for both disease-free and overall survival of breast cancer patients. CONCLUSION The data suggest that the expression of osteopontin-c could serve as a prognostic factor of breast cancer.

Insulin-like growth factor axis gene polymorphisms modify risk of pancreatic cancer.

OBJECTIVE Insulin-like growth factor (IGF)-axis genes plays a critical role in cancer development and progression via their impact on the RAS/MAPK/ERK and PI3K/AKT/mTOR signaling pathways. We hypothesized that IGF-axis genetic variants modify individual susceptibility to pancreatic cancer. METHODS We retrospectively genotyped 41 single-nucleotide polymorphisms of 10 IGF-axis genes (IGF1, IGF2, IGF1R, IGF2R, IGFBP1, IGFBP3, IGFBP5, IRS1, IRS2, and IRS4) in 706 pancreatic cancer patients and 706 cancer-free controls using Sequenom and TaqMan technology. The association between genotype and pancreatic cancer risk was evaluated using multivariate logistic regression. A P value ≤.007 at a false discovery rate of 10% was set as the significance level. RESULTS We observed that the IGF1 *10212C>A and Ex4+2776G>A and IGF1R IVS2-70184A>G and IVS2+46329T>C variant genotypes were significantly associated with decreased pancreatic cancer risk (odds ratio [OR] range, 0.60-0.75) and that IGFBP1 Ex4+111A>G (I253M) was significantly associated with increased pancreatic cancer risk (OR=1.46) after adjusted for other risk factors and multiple comparisons (P≤.007). IGF2R and IGFBP3 variant haplotypes were associated with increased and decreased pancreatic cancer risk, respectively (P<.001). We also observed a weak interaction of the IGF1R IVS2+46329T>C and IGF2R Ex45+11C>T (L2222L) genotypes with diabetes (P(interaction)=.05) and interaction of IGF2R and IRS1 genotypes with alcohol consumption (P(interaction)=.03 and .019, respectively) on increased pancreatic cancer risk. CONCLUSION These findings support our hypothesis that polymorphic variants of IGF-axis genes act alone or jointly with other risk factors to affect susceptibility to pancreatic cancer.

Ang II–AT1R Increases Cell Migration Through PI3K/AKT and NF‐κB Pathways in Breast Cancer

Angiotensin II (Ang II), a biologically active peptide of the renin–angiotensin system (RAS), plays an important role in promoting cell migration via Angiotensin II type 1 receptor (AT1R). In this study, we examined the mechanisms by which Ang II affected cell migration in AT1R‐positive MDA‐MB‐231 human breast cancer cells. Ang II increased cell migration and expression of matrix metalloproteinase (MMP)‐2,‐9 in a dose‐dependent manner. Ang II‐mediated cell migration was reduced by specific blocking of MMP‐2 and MMP‐9, as well as with pretreatment with inhibitors of AT1R, phosphatidylinositol 3‐kinase (PI3K), Akt, and NF‐κB. Similarly, Ang II‐mediated expression of MMP‐2,‐9 was downregulated by pretreatment with inhibitors of AT1R and PI3K. In addition, Ang II treatment significantly induced phosphorylation of PI3K, Akt, and resulted in increased NF‐κB activity. These findings suggest that Ang II activates the AT1R/PI3K/Akt pathway, which further activates IKKα/β and NF‐κB, resulting in enhanced expression of MMP‐2,‐9 and migration in human breast cancer cells. Therefore, targeting Ang II/AT1R/PI3K/Akt/NF‐κB signaling could be a novel anti‐metastatic therapy for breast cancer. J. Cell. Physiol. 229: 1855–1862, 2014.

ABCC3 as a marker for multidrug resistance in non-small cell lung cancer

Multidrug resistance (MDR) contributes to the failure of chemotherapy and high mortality in non-small cell lung cancer (NSCLC). We aim to identify MDR genes that predict tumor response to chemotherapy. 199 NSCLC fresh tissue samples were tested for chemosensitivity by MTT assay. cDNA microarray was done with 5 samples with highest resistance and 6 samples with highest sensitivity. Expression of ABCC3 mRNA and protein was detected by real-time PCR and immunohistochemisty, respectively. The association between gene expression and overall survival (OS) was examined using Cox proportional hazard regression. 44 genes were upregulated and 168 downregulated in the chemotherapy-resistant group. ABCC3 was one of the most up-regulated genes in the resistant group. ABCC3-positive expression correlated with lymph node involvement, advanced TNM stage, more malignant histological type, multiple-resistance to anti-cancer drugs, and reduced OS. ABCC3 expression may serve as a marker for MDR and predictor for poor clinical outcome of NSCLC.

Tea polyphenols induced apoptosis of breast cancer cells by suppressing the expression of Survivin.

To study the mechanism of tea polyphenols (TP)-induced apoptosis of breast cancer cells. Proliferation of MCF-7 and SK-BR-3 cells was evaluated by MTT assays. Cellular ultrastructure was examined by electron microscopy. Apoptosis was detected by TUNEL. PCNA、 Cyclin D1、 Cyclin E and Survivin expression was measured by Western blot. Cell proliferation was significantly inhibited by TP. Spindle and round cells were loosely distributed with increased particles after TP treatment. Increased cell size, frequent nuclear atypia and a collapse of apoptosis were observed. The nucleus was pushed towards one side, while the cytoplasm was rich in free ribosome. The membrane of mitochondria was thickening, and the cell apoptotic body was observed. TP treated cells experienced significantly enhanced apoptosis compared with 5-Fu treated or control groups. The expression of survivin was downregulated by TP. To conclude, TP can inhibit cell growth and induce apoptosis through downregulating the expression of survivin in breast cancer.

A cell-surface β-hydroxylase is a biomarker and therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a poor prognosis as a result of widespread intra‐ and extrahepatic metastases. There is an urgent need to understand signaling cascades that promote disease progression. Aspartyl‐(asparaginyl)‐β‐hydroxylase (ASPH) is a cell‐surface enzyme that generates enhanced cell motility, migration, invasion, and metastatic spread in HCC. We hypothesize that inhibition of its enzymatic activity could have antitumor effects. Small molecule inhibitors (SMIs) were developed based on the crystal structure of the ASPH catalytic site followed by computer‐assisted drug design. Candidate compounds were tested for inhibition of β‐hydroxylase activity and selected for their capability to modulate cell proliferation, migration, invasion, and colony formation in vitro and to inhibit HCC tumor growth in vivo using orthotopic and subcutaneous murine models. The biological effects of SMIs on the Notch signaling cascade were evaluated. The SMI inhibitor, MO‐I‐1100, was selected because it reduced ASPH enzymatic activity by 80% and suppressed HCC cell migration, invasion, and anchorage‐independent growth. Furthermore, substantial inhibition of HCC tumor growth and progression was observed in both animal models. The mechanism(s) for this antitumor effect was associated with reduced activation of Notch signaling both in vitro and in vivo. Conclusions: These studies suggest that the enzymatic activity of ASPH is important for hepatic oncogenesis. Reduced β‐hydroxylase activity generated by the SMI MO‐I‐1100 leads to antitumor effects through inhibiting Notch signaling cascade in HCC. ASPH promotes the generation of an HCC malignant phenotype and represents an attractive molecular target for therapy of this fatal disease. (Hepatology 2014;60:1302–1313)

Polymorphisms of the TLR4 gene and risk of gastric cancer

OBJECTIVE Toll-like receptor 4 (TLR4) is an important lipo-polysaccharide (LPS) receptor in gastric epithelial cell signaling transduction and plays critical roles in the development and progression of gastric cancer (GC). We investigated the effects of TLR4 gene polymorphisms and gene-environmental interactions on the risk of GC in Northeastern China. METHODS We genotyped two single-nucleotide polymorphisms (SNPs) in TLR4 (rs10116253 and rs1927911) in 217 GC patients and 294 cancer-free controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Odds ratio (OR) and 95% confidence intervals (CIs) were estimated by unconditional logistic-regression models. RESULTS Individuals carrying CC genotype of rs10116253 and TT genotype of rs1927911 had a significantly decreased risk of GC (adjusted OR=0.33, 95% CI 0.18-0.60, P<0.001 and adjusted OR=0.37, 95% CI 0.21-0.67, P=0.001 respectively), compared with TT genotype of rs10116253 and CC genotype of rs1927911. In addition, the SNP effects were additive to the effects of some known environmental factors without any interaction between them in the susceptibility to GC. CONCLUSION Our data suggested that TLR4 gene polymorphisms may be associated with a decreased risk of GC in Chinese population. And these SNPs and their combined effects with environmental factors may be associated with the risk of GC.