Significance of a novel sucrose permeability test using serum in the diagnosis of early gastric cancer

AIM: To investigate the usefulness of sucrose permeability test using serum in the diagnosis of gastric diseases, with special reference to early gastric cancer (EGC).METHODS: A total of 63 subjects, including 11patients with gastric ulcer, 20 patients with gastric cancer (13, early; 7, advanced) and 32 healthy controls,were studied. Blood and urine samples were collected repeatedly for 5 h before and after the sucrose loading.Sucrose levels were measured by a newly developed enzymatic method.RESULTS: Serum sucrose levels started to increase15 min after loading, and peaked at 60 min in the gastric disease groups. The levels for gastric ulcer, EGC and advanced gastric cancer (AGC) at 60 min were significantly higher than that in the healthy controls(26.9±2.4, 34.4±5.0, and 71.8±15.6 vs 7.9±0.7 mol/L,respectively, P＜0.01). The cut-off level set at 15.4 mol/L(60 min) offered the best distinction between EGC patients and healthy controls; and the sensitivity and specificity were 92.3% and 93.8%, respectively, while those of the urine method were 76.9% and 93.8%,respectively.CONCLUSIONS: The gastric permeability test using serum is reliable for the detection of EGC, and this test can provide results much earlier than the conventional urine method. This test may offer a useful alternative to more invasive tests for EGC.

The isolation and identification of apolipoprotein C-I in hormone-refractory prostate cancer using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry

Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients＇ sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points： point A, pre-treatment; point B, at the nadir of the prostate- specific antigen （PSA） level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients＇ sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I （ApoC-I）. Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-i protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.

Fractionation of gamma-glutamyltransferase in patients with nonalcoholic fatty liver disease and alcoholic liver disease

AIM To assess how serum gamma-glutamyltransferase(GGT) fractions vary in patients with alcoholic liver disease(ALD) and non-alcoholic fatty liver disease(NAFLD). METHODS Serum samples were obtained from 14 patients with biopsy-proven alcoholic liver diseases and 9 patients with biopsy proven non-alcoholic fatty liver disease. In addition to these biopsy-proven cases, 16 obese(body mass index > 25) patients without any history of alcohol consumption but with a fatty liver on ultrasound examination and with elevated GGT were included for an additional analysis. Serum GGT fractionation was conducted by high-performance gel filtration liquid chromatography and was separated into the four fractions, big-GGT, medium-GGT, small-GGT(s-GGT), and free-GGT(f-GGT).RESULTS The results were expressed as a ratio of each fraction including the total GGT(t-GGT). The s-GGT/t-GGT ratioswere lowest for the control group and highest for the ALD group. The differences between the control and NAFLD groups and also between the NAFLD and ALD groups were statistically significant. In contrast, the f-GGT/t-GGT ratios were highest in the control group and lowest in the ALD group, with the differences being statistically significant. As a result, the s-GGT/f-GGT ratios were markedly increased in the NAFLD group as compared with the control group. The increase of the s-GGT/t-GGT ratios, the decrease of the f-GGT/t-GGT ratios, and the increase of s-GGT/F-GGT ratios as compared with the control group subjects were also found in obese patients with clinically diagnosed fatty change of the liver.CONCLUSION Serum GGT fractionation by high-performance gel filtration liquid chromatography is potentially useful for the differential diagnosis of ALD and NAFLD.

Alternative splicing of DNA damage response genes and gastrointestinal cancers

Alternative splicing,which is a common phenomenon in mammalian genomes,is a fundamental process of gene regulation and contributes to great protein diversity.Alternative splicing events not only occur in the normal gene regulation process but are also closely related to certain diseases including cancer.In this review,we briefly demonstrate the concept of alternative splicing and DNA damage and describe the association of alternative splicing and cancer pathogenesis,focusing on the potential relationship of alternative splicing,DNA damage,and gastrointestinal cancers.We will also discuss whether alternative splicing leads to genetic instability,which is considered to be a driving force for tumorigenesis.Better understanding of the role and mechanism of alternative splicing in tumorigenesis may provide new directions for future cancer studies.

Non-transmissible Sendai virus vector encoding c-myc suppressor FBP-interacting repressor for cancer therapy

AIM:To investigate a novel therapeutic strategy to target and suppress c-myc in human cancers using far up stream element(FUSE)-binding protein-interacting repressor(FIR).METHODS:Endogenous c-Myc suppression and apoptosis induction by a transient FIR-expressing vector was examined in vivo via a HA-tagged FIR(HA-FIR)expression vector.A fusion gene-deficient,non-transmissible,Sendai virus(SeV)vector encoding FIR cDNA,SeV/dF/FIR,was prepared.SeV/dF/FIR was examined for its gene transduction efficiency,viral dose dependency of antitumor effect and apoptosis induction in HeLa(cervical squamous cell carcinoma)cells and SW480(colon adenocarcinoma)cells.Antitumor efficacy in a mouse xenograft model was also examined.The molecular mechanism of the anti-tumor effect and c-Myc suppression by SeV/dF/FIR was examined using Spliceostatin A(SSA),a SAP155 inhibitor,or SAP155siRNA which induce c-Myc by increasing FIR△exon2 in HeLa cells.RESULTS:FIR was found to repress c-myc transcription and in turn the overexpression of FIR drove apoptosis through c-myc suppression.Thus,FIR expressing vectors are potentially applicable for cancer therapy.FIR is alternatively spliced by SAP155 in cancer cells lacking the transcriptional repression domain within exon 2(FIR△exon2),counteracting FIR for c-Myc protein expression.Furthermore,FIR forms a complex with SAP155 and inhibits mutual well-established functions.Thus,both the valuable effects and side effects of exogenous FIR stimuli should be tested for future clinical application.SeV/dF/FIR,a cytoplasmic RNA virus,was successfully prepared and showed highly efficient gene transduction in in vivo experiments.Furthermore,in nude mouse tumor xenograft models,SeV/dF/FIR displayed high antitumor efficiency against human cancer cells.SeV/dF/FIR suppressed SSA-activated c-Myc.SAP155 siRNA,potentially produces FIR△exon2,and led to c-Myc overexpression with phosphorylation at Ser62.HA-FIR suppressed endogenous c-Myc expression and induced apoptosis in HeLa and SW480 cells.A c-myc transcriptional suppressor FIR expressing SeV/dF/FIR showed high gene transduction efficiency with significant antitumor effects and apoptosis induction in HeLa and SW480 cells.CONCLUSION:SeV/dF/FIR showed strong tumor growth suppression with no significant side effects in an animal xenograft model,thus SeV/dF/FIR is potentially applicable for future clinical cancer treatment.

Insulin gene enhancer protein 1 mediates glycolysis and tumorigenesis of gastric cancer through regulating glucose transporter 4

Background:Insulin gene enhancer protein 1,(ISL1),a LIM-homeodomain transcription factor,is involved in multiple tumors and is associated with insulin secretion and metabolic phenotypes.However,the role of ISL1 in stimulating glycolysis to promote tumorigenesis in gastric cancer(GC)is unclear.In this study,we aimed to characterize the expression pattern of ISL1 in GC patients and explore its molecular biological mechanism in glycolysis and tumorigenesis.Methods:We analyzed the expression and clinical significance of ISL1 in GC using immunohistochemistry and real-time polymerase chain reaction(PCR).Flow cytometry and IncuCyte assays were used to measure cell proliferation after ISL1 knockdown.RNA-sequencing was performed to identify differentially expressed genes,followed by Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis and Gene Set Enrichment Analysis(GSEA)to reveal key signaling pathways likely regulated by ISL1 in GC.Alteration of the glycolytic ability of GC cells with ISL1 knockdown was validated by measuring the extracellular acidification rate(ECAR)and oxygen consumption rate(OCR)and by detecting glucose consumption and lactate production.The expression of glucose transporter 4(GLUT4)and ISL1 was assessed by Western blotting,immunohistochemistry,and immunofluorescent microscopy.The luciferase reporter activity and chromatin immunoprecipitation assays were performed to determine the transcriptional regulation of ISL1 on GLUT4.Results:High levels of ISL1 and GLUT4 expression was associated with short survival of GC patients.ISL1 knockdown inhibited cell proliferation both in vitro and in vivo.KEGG analysis and GSEA for RNA-sequencing data indicated impairment of the glycolysis pathway in GC cells with ISL1 knockdown,which was validated by reduced glucose uptake and lactate production,decreased ECAR,and increased OCR.Mechanistic investigation indicated that ISL1 transcriptionally regulated GLUT4 through binding to its promoter.Conclusion:ISL1 facilitates glycolysis and tumorigenesis in GC via the transcriptional regulation of GLUT4.

Germline mutational profile of Chinese patients under 70 years old with colorectal cancer

Background:Inherited susceptibility accounts for nearly one-third of colorectal cancer(CRC)predispositions and has an 80%-100%lifetime risk of this disease.However,there are few data about germline mutations of hereditary CRC-related genes in Chinese patients with CRC.This study aimed to assess the prevalence of gene mutations related to cancer susceptibility among Chinese patients with CRC,differences between Chinese and Western patients,and the phenotypegenotype correlation.Methods:We retrospectively collected tumor samples from 526 patients with CRC under 70 years old who underwent hereditary CRC genetic testing.A series of bioinformatic analyses,as well as statistical comparisons,were performed.Results:We found that 77 patients(14.6%)harbored functional variants of the 12 genes.The mutation frequencies of the top 5 mutated genes were 6.5%for MutL homolog 1(MLH1),5.1%for MutS homolog 2(MSH2),1.0%for MSH6,0.8%for PMS1 homolog 2(PMS2),and 0.8%for APC regulator of the WNT signaling pathway(APC).Our data showed much higher rates of mutations of MSH6 and PMS2 genes among all mismatch repair(MMR)genes as compared with those in Western populations.Mutations in MLH1,MSH2,and MSH6 were found to be mutually exclusive.Patients with MLH1 or MSH2 mutations had higher frequencies of personal history of cancer(MLH1:20.6%vs.8.7%;MSH2:25.9%vs.8.6%)and family history of cancer than those without these mutations(MLH1:73.5%vs.48.4%;MSH2:70.4%vs.48.9%),and the lesions were more prone to occur on the right side of the colon than on the left side(MLH1:73.5%vs.29.3%;MSH2:56.0%vs.31.0%).The proportion of stage I/II disease was higher in patients with MLH1 mutations than in those without MLH1 mutations(70.6%vs.50.7%),and the rate of polyps was higher in patients withAPC mutations than in those with wild-type APC(75.0%vs.17.4%).Conclusion:These results provide a full-scale landscape of hereditary susceptibility over 12 related genes in CRC patients and suggest that a comprehensive multi-gene panel testing for hereditary CRC predisposition could be a helpful analysis in clinical practice.