Prognostic significance of X-ray cross-complementing gene 1 expression in gastric cancer

Objective： The aim of this study is to identify the prognostic significance of X-ray cross-complementing gene 1 （XRCCI） in patients with gastric cancer undergoing surgery and platinum-based adjuvant chemotherapy. Methods： Immunohistochemistry （IHC） was used to evaluate XRCCI protein expression profiles on surgical specimens of 612 gastric cancer patients. The relationship between XRCC1 expression and existing prognostic factors, platinum-based adjuvant chemotherapy, disease-free survival （DFS） and overall survival （OS） were analyzed. Results： Among 612 patients staged II/III in our study, 182 （29.74%） were evaluated as XRCC1 IHC positive. XRCC1 expression was not significantly related to OS （P=0.347） or DFS （P=0.297）. Compared with surgery only, platinum-based adjuvant chemotherapy significantly improved the OS （P=0.031）. And the patients with negative XRCC1 expression benefited more from platinum-based adjuvant chemotherapy （P=0.049）. Multivariate analysis demonstrated that tumor size, T category, N category, vascular or nerve invasion and platinum-based chemotherapy were good prognostic factors for OS （P〈0.05）. Though XRCCI plays an important role in DNA repair pathways, no significant relationship is found in XRCCI expression and OS among gastric cancer in our study. Conclusions： XRCC1 might be an alternative prognostic marker for the patients of gastric cancer after radical resection. The patients with negative XRCC1 expression can benefit more from platinum-based adjuvant chemotherapy.

miR-3622b-5p regulates cisplatin resistance of human gastric cancer cell line by targeting BIRC5

Many evidences showed that drug resistance of gastric cancer cells could be regulated by the abnormal expression of microRNAs(miRNAs),a post-transcriptional regulator of gene expression.Thus,we investigated the role of miR-3622b-5p in the development of cisplatin resistance in human gastric cancer cell lines.A set of biochemical assays were used to elucidate the mechanism by which miR-3622b-5p regulates drug resistance in cancer cells.The expression of miR-3622b-5p was measured by quantitative real-time PCR and showed that MiR-3622b-5p was significantly downregulated in the plasma of patients with acquired drug resistance to platinumbased chemotherapy for gastric cancer.MiR-3622b-5p was also found significantly downregulated in cisplatinresistant gastric cancer cell line SGC7901/cisplatin(DDP),compared with the parental SGC7901 cells.An in vitro drug sensitivity assay showed that overexpression of miR-3622b-5p sensitized SGC7901/DDP cells to cisplatin.The luciferase activity of reporters constructed by BIRC53′-untranslated regions in SGC7901/DDP cells suggested that BIRC5 was target gene of miR-3622b-5p.Ecpotic miR-3622b-5p expression in SGC7901/DDP cells significantly repressed the expression of the BIRC5 and sensitized the cells to DDP-induced apoptosis.By contrast,treatment with miR-3622b-5p inhibitor increased the protein expression of BIRC5 and led to a lower proportion of apoptotic cells in the SGC7901 cells.In conclusion,our findings suggest that miR-3622b-5p regulates cisplatin resistance of human gastric cancer cells at least in part by repressing the expression of BIRC5.Altering miR-3622b-5p expression may be a potential therapeutic strategy for the treatment of chemoresistance in GC in the future.

Bitumen formation of Cambrian Longwangmiao Formation in the central Sichuan and its implication for hydrocarbon accumulation

Based on organic petrology,organic geochemistry and SEM method,type,formation period and source of bitumens in the Cambrian Longwangmiao Formation in the central Sichuan Basin were well investigated,and combined with fluid inclusions and tectonic evolution characteristics,the hydrocarbon accumulation history of the gas reservoir of the Longwangmiao Formation in the Anyue gasfield was also studied.The result shows that all bitumens in the Longwangmiao Formation was from the Lower Cambrian source rocks,it had multiple genetic types which was dominated by the pyrolysis genetic type;the bitumens were formed into three stages,i.e.,the bitumen of the oxidized water-washing type in the first stage,the bitumen of the precipitated type in the second stage,and the bitumen of the pyrolyzed type in the third stage;the gas reservoir in the Anyue gasfield experienced five stages of hydrocarbon charging,including two stages of liquid hydrocarbon charging,charging of the kerogen pyrolysis gas in the Late Triassic-Early Jurassic,charging of the crude oil pyrolysis gas in the Late Jurassic-Early Cretaceous and charging of the dry gas charging in the Himalayan trap reformation and adjustment process.

Hydrocarbon generation characteristics and exploration prospects of Proterozoic source rocks in China

A large number of primary oil and gas reservoirs have been discovered in Proterozoic strata all over the globe.Proterozoic sequences are widely distributed in China, and the discovery of large Sinian-aged gas reservoirs in the Sichuan Basin and Mesoproterozoic liquid oil seepages in North China shows that attention should be paid to the exploration potential of Proterozoic strata. In this paper, the main controlling factors of Proterozoic source rocks are discussed. Principally, active atmospheric circulation and astronomical cycles may have driven intense upwelling and runoff to provide nutrients; oxygenated oceanic surface waters could have provided suitable environments for the organisms to thrive; volcanic activity and terrestrial weathering caused by continental break-up would have injected large amounts of nutrients into the ocean, leading to persistent blooms of marine organisms; and extensive anoxic deep waters may have created ideal conditions for the preservation of organic matter. Additionally, the appearance of eukaryotes resulted in diversified hydrocarbon parent material, which effectively improved the generation potential for oil and gas. Through the comparison of Formations across different cratons, seven sets of Proterozoic organic-rich source rocks have been recognized in China, which mainly developed during interglacial periods and are also comparable worldwide. The Hongshuizhuang and Xiamaling Formations in North China have already been identified previously as Mesoproterozoic source rocks. The early Proterozoic Changchengian System is highly promising as a potential source rock in the Ordos Basin. In the Upper Yangtze area, the Neoproterozoic Datangpo and Doushantuo Formations are extensively distributed, and represent the major source rocks for Sinian gas reservoirs in the Sichuan Basin. Moreover, the Nanhuan System may contain abundant shales with high organic matter contents in the Tarim Basin, although this possibility still needs to be verified. Indeed, all three cratons may contain source rocks of Proterozoic strata; thus, these strata represent major exploration targets worthy of great attention.

Characteristics of Changchengian rifts in southern margin of North China Craton and its hydrocarbon geological conditions

The Meso-Neoproterozoic strata are wildly distributed in North China Craton(NCC),of which Changchengian strata are most widely developed.Taking Changchengian strata in south margin of NCC as the study object,and combined with comprehensive analysis of isotopic chronology and petrology,it can be concluded that the Xiong'er rift is a plume rift which responds to breakup of Columbia supercontinent.Seismic data shows that Changchengian rifts are developed in the Qinshui Basin and the southern part of Ordos Basin covered by Phanerozoic strata,respectively are large-scale graben rifts and half-graben rifts.Aero magnetic data indicates that a NE-trending rift is developed in the west of the Xiong'er rift,and the Qinshui Basin rift is the extension of the north branch of the Xiong'er rift.The filling process of Changchengian rifts can be divided into four stages:the early rifting stage developing thick andesitic volcanic rocks,the late rifting stage developing large suite of coarse clastic sedimentary rocks,the depression stage developing fine clastic rocks,and the epeiric sea stage developing carbonate rocks.The dark argillaceous rocks are developed in Cuizhuang Formation and Chenjiajian Formation during the depression stage,and the black shale in Cuizhuang Formation is the effective source rocks.The bitume is filled in fractures of dolomite in Luoyukou Formation,as well as dissolution pores and large caves in Longjiayuan Formation.The argillaceous sandstone and muddy limestone of Lower Cambrian is the effective cap rocks,which can form an potential accumulation assemblage of Changchengian strata with underlying source rocks of Cuizhuang Formation and reservoirs of Luoyu Group,and this assemblage may be still effective at present.

Value of negatively correlated miR-205-5p/HMGB3 and miR-96-5p/FOXO1 on the diagnosis of breast cancer and benign breast diseases

Background:MicroRNA(miRNA)and mRNA levels in matching specimens were used to identify miRNA–mRNA interactions.We aimed to integrate transcriptome,immunophenotype,methylation,mutation,and survival data analyses to examine the profiles of miRNAs and target mRNAs and their associations with breast cancer(BC)diagnosis.Methods:Based on the Gene Expression Omnibus(GEO)database and The Cancer Genome Atlas(TCGA),differentially expressed miRNAs and targeted mRNAs were screened from experimentally verified miRNA-target interaction databases using Pearson's correlation analysis.We used real-time quantitative reverse transcription polymerase chain reaction to verify BC and benign disease samples,and logistic regression analysis was used to establish a diagnostic model based on miRNAs and target mRNAs.Receiver operating characteristic curve analysis was performed to test the ability to recognize the miRNA-mRNA pairs.Next,we investigated the complex interactions between miRNA-mRNA regulatory pairs and phenotypic hallmarks.Results:We identified 27 and 359 dysregulated miRNAs and mRNAs,respectively,based on the GEO and TCGA databases.Using Pearson's correlation analysis,10 negative miRNA-mRNA regulatory pairs were identified after screening both databases,and the related miRNA and target mRNA levels were assessed in 40 BC tissues and 40 benign breast disease tissues.Two key regulatory pairs(miR-205-5p/High mobility group box 3(HMGB3)and miR-96-5p/Forkhead Box O1(FOXO1))were selected to establish the diagnostic model.They also had utility in survival and clinical analyses.Conclusions:A diagnostic model including two miRNAs and their respective target mRNAs was established to distinguish between BC and benign breast diseases.These markers play essential roles in BC pathogenesis.