Association between AXIN1 Gene Polymorphisms and Bladder Cancer in Chinese Han Population

Association of AXIN1 rs12921862 C/A and rs1805105 G/A and CTSB rs12898 G/A polymorphisms with papillary thyroid carcinoma: A case-control study

BACKGROUND

Papillary thyroid cancer (PTC) is the most common type of thyroid cancer which its precise etiology remains unknown. However, environmental and genetic factors contribute to the etiology of PTC. Axis inhibition protein 1 (Axin1) is a scaffold protein that exerts its role as a tumor suppressor. In addition, Cathepsin B (Ctsb) is a cysteine protease with higher expression in several types of tumors. Therefore, the aim of this study was to investigate the possible association of AXIN1 rs12921862 C/A and rs1805105 G/A and CTSB rs12898 G/A polymorphisms with PTC susceptibility.

MATERIALS & METHODS

In total, 156 PTC patients and 158 sex-, age-, and BMI-matched control subjects were enrolled in the study. AXIN1 rs12921862 C/A and rs1805105 G/A and CTSB rs12898 G/A polymorphisms were genotyped using the PCR-RFLP method.

RESULTS

There was a relationship between AXIN1 rs12921862 C/A polymorphism and an increased risk of PTC in all genetic models except the overdominant model. The AXIN1 rs1805105 G/A polymorphism was associated with an increased PTC risk only in codominant and overdominant models. The frequency of AXIN1 A_rs12921862 A_rs1805105 haplotype was higher in the PTC group and also this haplotype was associated with an increased risk of PTC. Moreover, the AXIN1 rs12921862 C/A polymorphism was not associated with PTC clinical and pathological findings, but AXIN1 rs1805105 G/A polymorphism was associated with almost three folds of larger tumor size (≥1 cm). There was no association between CTSB rs12898 G/A polymorphism and PTC and its findings.

CONCLUSION

The AXIN1 rs12921862 C/A and rs1805105 G/A polymorphisms were associated with PTC. AXIN1 rs1805105 G/A polymorphism was associated with higher tumor size.

Identification of FtpA, a Dps-like protein involved in anti-oxidative stress and virulence in Actinobacillus pleuropneumoniae

Bacteria have evolved a variety of enzymes to eliminate endogenous or host-derived oxidative stress factors. The Dps protein, first identified in Escherichia coli, contains a ferroxidase center and protects bacteria from reactive oxygen species damage. There is a lack of knowledge of the role of Dps-like proteins in bacterial pathogenesis. Actinobacillus pleuropneumoniae causes pleuropneumonia, a respiratory disease of swine. The A. pleuropneumoniae ftpA gene is up-regulated during a shift to anaerobiosis, in biofilms and, as found in this study, also by H₂O₂. An A. pleuropneumoniae ftpA deletion mutant (△ftpA) had increased H₂O₂ sensitivity, less intracellular viability in macrophages, and decreased virulence in a mouse infection model. Expression of ftpA in an E. coli dps mutant restored wild-type resistance to H₂O₂. FtpA possesses a conserved ferritin domain containing a ferroxidase site. Recombinant rFtpA bound and oxidized Fe²⁺ reversibly. Under aerobic conditions, compared with the wild-type strain, the viability of an △ftpA mutant was reduced after extended culture, transition from anaerobic to aerobic conditions, and upon supplementation with Fenton reaction substrates. Under anaerobic conditions, additional H₂O₂ resulted in a more severe growth defect of △ftpA than under aerobic conditions. Therefore, by oxidizing and mineralizing Fe²⁺, FtpA alleviates oxidative damage mediated by intracellular Fenton reactions. Furthermore, by mutational analysis, two residues were confirmed to be critical for Fe²⁺ binding and oxidization, as well as for A. pleuropneumoniae H₂O₂ resistance. Taken together, this study demonstrates that A. pleuropneumoniae FtpA is a Dps-like protein, playing critical roles in oxidative stress resistance and virulence. IMPORTANCE As a ferroxidase, Dps of Escherichia coli can protect bacteria from reactive oxygen species damage, but its role in bacterial pathogenesis has received little attention. In this study, FtpA of the swine respiratory pathogen A. pleuropneumoniae was identified as a new Dps-like protein. It facilitated A. pleuropneumoniae resistance to H₂O₂, survival in macrophages, and infection in vivo. FtpA could bind and oxidize Fe²⁺ through two important residues in its ferroxidase site and protected the bacteria from oxidative damage mediated by the intracellular Fenton reaction. These findings provide new insights into the role of the FtpA-based antioxidant system in the pathogenesis of A. pleuropneumoniae, and the conserved Fe²⁺ binding ligands in Dps/FtpA provide novel drug target candidates for disease prevention.

Significant Associations between AXIN1 rs1805105, rs12921862, rs370681 Haplotypes and Variant Genotypes of AXIN2 rs2240308 with Risk of Congenital Heart Defects

This study aimed to investigate possible associations of the susceptibility to congenital heart defects (CHDs) with AXIN1 rs1805105, rs12921862 and rs370681 gene variants and haplotypes, and AXIN2 rs2240308 gene variant. Significant associations were identified for AXIN1 rs370681 and AXIN2 rs2240308 variants. AXIN1 rs370681 variant was significantly associated with decreased odds of CHDs (adjusted OR varying from 0.13 to 0.28 in codominant, dominant and recessive gene models), while the AXIN2 rs2240308 variant was associated with increased odds of CHD in the dominant model. The haplotype-based generalized linear model regression of AXIN1 rs1805105, rs12921862 and rs370681 variants revealed that C-C-C and C-C-T haplotypes significantly increased the risk of CHDs (p < 0.05). No significant second order epistatic interactions were found between investigated variants (AXIN1 rs1805105, rs12921862, rs370681, and AXIN2 rs2240308). Our conclusion is that AXIN1 rs1805105, rs12921862, and rs370681 (C-C-C and C-C-T) haplotypes and AXIN2 rs2240308 contribute to CHDs susceptibility.

Regulation of Wnt Signaling through Ubiquitination and Deubiquitination in Cancers

The Wnt signaling pathway plays important roles in embryonic development, homeostatic processes, cell differentiation, cell polarity, cell proliferation, and cell migration via the β-catenin binding of Wnt target genes. Dysregulation of Wnt signaling is associated with various diseases such as cancer, aging, Alzheimer’s disease, metabolic disease, and pigmentation disorders. Numerous studies entailing the Wnt signaling pathway have been conducted for various cancers. Diverse signaling factors mediate the up- or down-regulation of Wnt signaling through post-translational modifications (PTMs), and aberrant regulation is associated with several different malignancies in humans. Of the numerous PTMs involved, most Wnt signaling factors are regulated by ubiquitination and deubiquitination. Ubiquitination by E3 ligase attaches ubiquitins to target proteins and usually induces proteasomal degradation of Wnt signaling factors such as β-catenin, Axin, GSK3, and Dvl. Conversely, deubiquitination induced by the deubiquitinating enzymes (DUBs) detaches the ubiquitins and modulates the stability of signaling factors. In this review, we discuss the effects of ubiquitination and deubiquitination on the Wnt signaling pathway, and the inhibitors of DUBs that can be applied for cancer therapeutic strategies.

Axin1 inhibits proliferation, invasion, migration and EMT of hepatocellular carcinoma by targeting miR-650

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high mortality rate and low survival rate. This study was designed to explore a novel molecular with high sensitivity and specificity, which can be applied in early diagnosis and therapeutic evaluation of HCC. The current study aims to investigate the effect and important role of Axin1 on cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma. qRT-PCR results showed lower Axin1 expression level and higher miR-650 expression level in HCC. Luciferase reporter assay was carried out to verify the negative correlation between Axin1 and miR-650 mRNA levels. CCK-8 assay results showed that the cell proliferation ability was significantly suppressed by Axin1 overexpression in SK-HEP-1 cells. The results in wound healing assay uncovered that cell migration ability was markedly suppressed by Axin1 overexpression. The results in trans-well invasion assay showed that Axin1 overexpression caused decreased invasive ability in SK-HEP-1 cells. The WB results showed that the protein level of E-cad was significantly increased and the protein levels of N-cad, vimentin and snail were obviously reduced following Axin1 overexpression. Whereas, the suppressive effects on cell proliferation, migration, invasion and EMT caused by Axin1 overexpression were abolished by miR-650 mimic. All the results in the current study confirmed the truth that Axin1 overexpression could suppress cell proliferation, migration, invasion and EMT by downregulating miR-650 expression.