Mutation of Disulfide Bond Sites Reduces the Immunoreactivity of Cra a 4 by Changing the Structural Characteristics.

Sarcoplasmic calcium-binding protein (Cra a 4) from Crassostrea angulata belongs to the EF-hand superfamily, and understanding of its structure-allergenicity relationship is still insufficient. In this study, chemical denaturants were used to destroy the structure of Cra a 4, showing that disruption of the structure reduced its IgG-/IgE-binding activity. To explore which critical amino acid site affects the allergenicity of Cra a 4, the mutants were obtained by site-directed mutations in the disulfide bonds site (C97), conformational epitopes (I105, D114), or Ca2+-binding region (D106, D110) and their IgG-/IgE-binding activity was reduced significantly using serological tests. Notably, C97A had the lowest immunoreactivity. In addition, two conformational epitopes of Cra 4 were verified. Meanwhile, the increase of the α-helical content, surface hydrophobicity, and surface electrostatic potential of C97A affected its allergenicity. Overall, the understanding of the structure-allergenicity relationship of Cra a 4 allowed the development of a hypoallergenic mutant.

Efficacy of Endoscopic Tissue Adhesive in Patients with Gastrointestinal Tumor Bleeding.

BACKGROUND: Gastrointestinal tumors bleeding remains a significantly clinical challenge due to its resistance to conventional endoscopic hemostasis methods. While the efficacy of endoscopic tissue adhesives (ETA) in variceal bleeding has been established, its role in gastrointestinal tumor bleeding (GITB) remains ambiguous. AIMS: This study aims to assess the feasibility and effectiveness of ETA in the treatment of GITB. METHODS: The study enrolled 30 patients with GITB who underwent hemostasis through Histoacryl® tissue glue injection. Hemostasis success rates, ETA-related adverse events, and re-bleeding rates were evaluated. RESULTS: ETA application achieved successful hemostasis at all tumor bleeding sites, with immediate hemostasis observed in all 30 (100.0%) patients. Among the initially hemostasis cases, 5 patients (17.0%) experienced re-bleeding within 30 days, and the 60 day re-bleeding rate was 20.0% (6/30). Expect for one case of vascular embolism, no adverse events related with ETA application were reported. The 6 month survival was 93%. CONCLUSION: ETA demonstrated excellent immediate hemostasis success rate in GITB cases and showed promising outcomes in prevention re-bleeding.

Circ-EIF3I Promotes Hepatocellular Carcinoma Progression Through Modulating miR-361-3p/DUSP2 Axis.

Hepatocellular carcinoma (HCC) is one of the most common malignant cancers globally. Circular RNAs (circRNAs) have been implicated in the development of HCC. Previous studies have confirmed that circ-EIF3I plays an important role in the progress of lung cancer. Nevertheless, the biological functions of circ-EIF3I and the underlying mechanisms by which they regulate HCC progression remain unclear. In this study, the regulatory mechanism and targets were studied with bioinformatics analysis, luciferase reporting analysis, transwell migration, Cell Counting Kit-8, and 5-Ethynyl-2'-deoxyuridine analysis. In addition, in vivo tumorigenesis and metastasis assays were employed to evaluate the roles of circ-EIF3I in HCC. The result shows that the circ-EIF3I expression was increased in HCC cell line, which means that circ-EIF3I plays a role in the progression of HCC. Downregulation of circ-EIF3I suppressed HCC cells' proliferation and migration in both in vivo and in vitro experiments. Bioinformatics and luciferase report analysis confirmed that both miR-361-3p and Dual-specificity phosphatase 2 (DUSP2) were the downstream target of circ-EIF3I. The overexpression of DUSP2 or inhibition of miR-361-3p restored HCC cells' proliferation and migration ability after silence circ-EIF3I. Taken together, our study found that downregulation of circ-EIF3I suppressed the progression of HCC through miR-361-3p/DUSP2 Axis.

CircRNA DONSON contributes to cisplatin resistance in gastric cancer cells by regulating miR-802/BMI1 axis.

BACKGROUND: Circular RNA downstream neighbor of SON (circDONSON) has been revealed to promote gastric cancer (GC) growth and invasion, while the role and molecular mechanism underlying circDONSON in GC cisplatin (DDP) resistance remain unclear. METHODS: Levels of circDONSON, microRNA (miR)-802, and B lymphoma Mo-MLV insertion region 1 (BMI1) mRNA were detected using quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit-8 assay, colony formation assay and flow cytometry, respectively. Protein levels of BMI1, Cyclin D1, p27, Caspase-3 Cleavage and Caspase-9 Cleavage were determined by western blot. The interaction between miR-802 and circDONSON or BMI1 was confirmed by dual-luciferase reporter assay. In vivo experiments were conducted via the murine xenograft model. RESULTS: CircDONSON was elevated in GC tissues and cell lines, especially in DDP-resistant GC tissues and cells. Knockdown of circDONSON sensitized GC cells to DDP by inhibiting cell viability and promoting cell apoptosis in vitro. Further mechanism-related investigations suggested that circDONSON functioned as "sponge" by competing for miR-802 binding to modulate its target BMI1. Silencing miR-802 reversed the inhibition of DDP-resistance in GC cells induced by circDONSON down-regulation. Besides, miR-802 alleviated DDP resistance in GC cells by targeting BMI1. Functionally, circDONSON knockdown enhanced the cytotoxicity of DDP in GC in vivo. CONCLUSION: Our findings demonstrated circDONSON promoted cisplatin resistance in gastric cancer cells by regulating miR-802/BMI1 axis, shedding light on the development of a novel therapeutic strategy to overcome chemoresistance in gastric cancer patients.

Electrostatic explanation of D1228V/H/N-induced c-Met resistance and sensitivity to type I and type II kinase inhibitors in targeted gastric cancer therapy.

The c-Met D1228V/H/N mutation clinically causes acquired resistance to type I tyrosine kinase inhibitors (TKIs), while maintaining sensitivity to type II TKIs in targeted gastric cancer therapy. The mutation is located in the activation loop (A-loop) region of the c-Met kinase domain, which substitutes the negatively charged residue Asp1228 with electroneutral amino acid Val, His, or Asn, thus electrostatically destabilizing the DFG-in conformation of A-loop and inducing its transition to DFG-out state. The transition is spontaneous in a dynamics point of view and the A-loop exhibits a large intrinsic disorder during the transitional dynamics course. In DFG-in conformation, the wild-type Asp1228 is surrounded by a number of positively charged residues within its first and second shells, which can also form a hydrogen-bonding network with its vicinal residues Phe1089, Lys1110, Asp1222, and Met1229 in the first shell. Type I and type II TKIs respond oppositely to the mutation; the former shows a generic resistance to the mutation, whereas the latter is generally sensitized by the mutation. Both types of TKIs do not directly interact with the mutation. Instead, the mutation-induced conformational change in A-loop reshapes kinase active site and then influences the site interactions with inhibitor ligands, thus conferring different selectivity to the type I and type II TKIs. Graphical abstract The molecular mechanism of D1228V/H/N mutation-induced inhibitor resistance and sensitivity in c-Met kinase is investigated. The mutation electrostatically destabilizes the DFG-in conformation of kinase A-loop and induces its spontaneous transition to DFG-out state, which reshapes kinase active site and influences the site interactions with inhibitor ligands.

Association between functional PSMD10 Rs111638916 variant regulated by MiR-505 and gastric cancer risk in a Chinese population.

BACKGROUND/AIMS: Gankyrin is an oncoprotein involved in regulating the cell cycle through protein-protein interactions with cyclin-dependent kinase 4 and p53. However, its association with gastric cancer (GC) risk has not yet been determined. In this study, we investigated micro RNA (miRNA)-associated single nucleotide polymorphisms (SNPs) in the 3'-untranslated region (UTR) of the gankyrin gene PSMD10 to clarify the relationship between these SNPs and miRNAs in Chinese patients with GC. METHODS: We performed a case-control study including 857 GC patients and 748 cancer-free controls. PSMD10 expression was investigated using genotyping, real-time polymerase chain reaction, cell transfection, and dual luciferase reporter assays. RESULTS: Patients with histories of smoking, alcohol consumption, and cancer were more susceptible to GC than controls. The SNP rs111638916 in the PSMD10 3'-UTR was identified as a risk factor for GC and acted as a tumor promoting factor. SNP rs111638916 was also regulated by miR-505, resulting in up-regulation of gankyrin expression in patients with GA and AA genotypes. Carriers of the GA and AA genotypes also presented with larger tumors and had a higher risk of metastasis. CONCLUSION: The PSMD10 rs111638916 SNP is highly associated with an increased risk of GC in Chinese patients, and could serve as a novel biomarker for this disease.

Risk of hepatitis B virus (HBV) reactivation in non-Hodgkin lymphoma patients receiving rituximab-chemotherapy: a meta-analysis.

BACKGROUND: The addition of Rituximab to standard chemotherapy (C) has been reported to improve the end of treatment outcome in non-Hodgkin lymphoma (NHL) patients. Nevertheless, rituximab has been associated with hepatitis B virus reactivation (HBV-R). OBJECTIVES: The aim of this systematic review and meta-analysis is to research the relationship between rituximab and HBV-R. STUDY DESIGN: We searched the commonly used databases both in English and Chinese from November 1997 to June 30, 2012. Meta-analysis was performed in fixed/random-effects models using Review Manager 5.1 and STATA 10.0. Publication bias was examined through Egger's test and Begg's funnel plot. RESULTS: Nine eligible articles were selected in this review (8 studies in English and 1 studies in Chinese), which included 971 adult patients and met all inclusion and exclusion criteria. Of rituximab-associated HBV-R cases reported through case series (n=387), 304 were HBcAb (+)/HBsAg (-) and 83 HBsAg (+). The pooled effect of rituximab-based therapy on HBV-R significantly increased under fixed-effects model [Relative risk (RR) 2.14, 95%CI 1.42-3.22, P=0.0003]. In subgroup analysis, rituximab-associated HBV-R in isolated HBcAb (+) patients remained high, and the RR was 5.52 (95%CI 2.05-14.85, P=0.0007). The RR of HBV-R in NHL patients with HBsAg (+) treated with R-based therapy when compared with the control population was 1.63 by the random-effects model. CONCLUSIONS: Rituximab therapy may increase the risk of developing HBV-R in NHL patients with HBcAb(+).

Multidrug resistance gene (MDR1) polymorphisms correlate with imatinib response in chronic myeloid leukemia.

The human multidrug resistance gene (MDR1, ABCB1) codes for P-glycoprotein (P-gp) that affects the pharmacokinetics of many drugs. MDR1 single nucleotide polymorphisms (SNPs) are associated with drug clearance. Imatinib is a substrate of P-gp-mediated efflux. We investigated the MDR1 T1236C, G 2677T/A, and C3435T polymorphism in 52 patients with chronic myeloid leukemia treated with imatinib. The distribution of MDR1 1236, 2677, or 3435 genotypes was significantly different between the resistance patients and sensitivity patients. The resistance incidence correlated with the number of T alleles at locus 1236 and 3435. Resistance was higher for patients homozygous for the 1236T allele when compared to patients with CT/CC genotype groups (75% vs. 31.3%, P = 0.004). For the G2677T/A polymorphism, a better complete cytogenetic remission was observed for patients with genotype AG/AT/AA, when compared to other genotype groups (TT/GT/GG, P = 0.02). Patients with 3435 TT/CT genotypes showed a higher resistance when compared with patients with CC genotype (59.4% vs. 25%, P = 0.023). In conclusion, determination of 1236T, C3435T, and G2677T MDR1 polymorphisms might be useful in response prediction to therapy with imatinib in patients with CML.

Chronic myeloid leukemia patients sensitive and resistant to imatinib treatment show different metabolic responses.

The BCR-ABL tyrosine kinase inhibitor imatinib is highly effective for chronic myeloid leukemia (CML). However, some patients gradually develop resistance to imatinib, resulting in therapeutic failure. Metabonomic and genomic profiling of patients' responses to drug interventions can provide novel information about the in vivo metabolism of low-molecular-weight compounds and extend our insight into the mechanism of drug resistance. Based on a multi-platform of high-throughput metabonomics, SNP array analysis, karyotype and mutation, the metabolic phenotypes and genomic polymorphisms of CML patients and their diverse responses to imatinib were characterized. The untreated CML patients (UCML) showed different metabolic patterns from those of healthy controls, and the discriminatory metabolites suggested the perturbed metabolism of the urea cycle, tricarboxylic acid cycle, lipid metabolism, and amino acid turnover in UCML. After imatinib treatment, patients sensitive to imatinib (SCML) and patients resistant to imatinib (RCML) had similar metabolic phenotypes to those of healthy controls and UCML, respectively. SCML showed a significant metabolic response to imatinib, with marked restoration of the perturbed metabolism. Most of the metabolites characterizing CML were adjusted to normal levels, including the intermediates of the urea cycle and tricarboxylic acid cycle (TCA). In contrast, neither cytogenetic nor metabonomic analysis indicated any positive response to imatinib in RCML. We report for the first time the associated genetic and metabonomic responses of CML patients to imatinib and show that the perturbed in vivo metabolism of UCML is independent of imatinib treatment in resistant patients. Thus, metabonomics can potentially characterize patients' sensitivity or resistance to drug intervention.