Shegan Gao

Nrf2 Overexpression Predicts Prognosis and 5-FU Resistance in Gastric Cancer

OBJECTIVE NF-E2-related factor 2 (Nrf2) is activated in several human malignancies. However, the role of Nrf2 in gastric cancer (GC) remains incompletely understood. In this study, we therefore analyzed associations of Nrf2 expression status with clinical features and chemotherapeutic resistance in GC. MATERIALS AND METHODS A total of 186 samples from GC patients who underwent gastrectomy were used for prognostic assessment. A further 142 samples from GC cases who received first-line combination chemotherapy were applied for investigation of chemoresistance. The Nrf2 expression was evaluated by immunohistochemistry in GC samples, and its relationship with clinicopathological parameters and chemotherapy sensitivity was analyzed. The effect of Nrf2 gene silencing on chemotherapy resistance was also examined by cell viability assay in vivo. RESULTS Of the 186 patients with GC, 104/186 (55.9%) showed high expression for Nrf2. The overexpression of Nrf2 was an independent predictor of overall survival [OS, hazard ratio (HR) 3.9; P=0.011] and disease-free survival (DFS, HR 4.3; P=0.002). The gene silencing of Nrf2 reduced resistance to cell death induced by 5-FU in GC cell lines. CONCLUSION Our data show that Nrf2 is an independent prognostic factor in GC. Furthermore, Nrf2 confers resistance to chemotherapeutic drug 5-FU in GC cells. Taken together, Nrf2 is a potential prognostic marker and predictive for 5-FU resistance in GC.

Microarray Expression Profile Analysis of Long Non-Coding RNAs in Human Gastric Cardiac Adenocarcinoma

Background/Aims: Long noncoding RNAs (lncRNAs) are pervasively transcribed and have been shown to regulate key biological processes that maintain normal cellular functions. Abnormal regulation of these lncRNAs can promote tumorigenesis through resulting aberrant cellular essential functions. however, the roles of lncRNAs played in the development of gastric cardiac adenocarcinoma (GCA) remain unknown. With this work we aimed to show the expression profile of lncRNAs in GCA tissues compared with paired adjacent noncancerous tissue using microarray analysis in order to interrogate potential carcinogenesis molecular mechanisms of GCA from lncRNA level. Methods: In this study, total RNA was isolated from 15 pairs of GCA tissue, cancerous and non-cancerous, and hybridized to arraystar lncRNA V2.0 chips containing probes representing 33,000 lncRNA genes. Quantitative real-time polymerase chain reaction (PCR) was used to validate 6 up-regulated and 6 down-regulated lncRNAs. Bioinformatic analysis including gene ontology(GO) analysis, pathway analysis and network analysis was done for further investigation. Results: Pathway analysis indicated that 8 pathways corresponded to downregulated transcripts and that 20 pathways corresponded to up-regulated transcripts (p-value cut-off is 0.05). GO analysis showed that the highest enriched GOs targeted by up-regulated transcripts were tissue homeostasis and the highest esenriched GOs targeted by the downregulated transcripts were tissue homeostasis. Conclusion: Our study is the first to interrogate differentially expressed lncRNAs in human GCA tissues and indicates that lncRNAs may be used as novel candidate biomarkers for the clinical diagnosis of GCA and potential targets for further therapy.

The Chk1 inhibitor AZD7762 sensitises p53 mutant breast cancer cells to radiation in vitro and in vivo.

AZD7762, a novel checkpoint kinase 1 (Chk 1)inhibitor, has been proven to sensitize various tumor cells to DNA damage. However, whether or not AZD7762 sensitizes breast cancer cells to radiation has not been defined. In the present study, we aimed to demonstrate for the first time, that AZD7762 not only promotes radiation-induced apoptosis and mitotic catastrophe of p53 mutant T47D breast cancer cells in vitro, but also delays their xenograft growth in response to radiation in vivo. Our mechanistic study showed that AZD7762 treatment resulted in the abrogation of radiation-induced G2/M arrest and the inhibition of radiation damage repair as demonstrated by increased radiation-induced γH2AX expression and decreased RAD51 protein expression. These results suggest that AZD7762 may effectively abrogate radiation-induced G2/M arrest and inhibit radiation damage repair in conferring radiosensitivity on p53 mutant T47D breast cancer cells, by promoting radiation-induced apoptosis and mitotic catastrophe. The clinical application of AZD7762, as an adjuvant in the radiotherapy of breast cancers, should be further explored.

The Role of JAK-3 in Regulating TLR-Mediated Inflammatory Cytokine Production in Innate Immune Cells

The role of JAK-3 in TLR-mediated innate immune responses is poorly understood, although the suppressive function of JAK3 inhibition in adaptive immune response has been well studied. In this study, we found that JAK3 inhibition enhanced TLR-mediated immune responses by differentially regulating pro- and anti- inflammatory cytokine production in innate immune cells. Specifically, JAK3 inhibition by pharmacological inhibitors or specific small interfering RNA or JAK3 gene knockout resulted in an increase in TLR-mediated production of proinflammatory cytokines while concurrently decreasing the production of IL-10. Inhibition of JAK3 suppressed phosphorylation of PI3K downstream effectors including Akt, mammalian target of rapamycin complex 1, glycogen synthase kinase 3β (GSK3β), and CREB. Constitutive activation of Akt or inhibition of GSK3β abrogated the capability of JAK3 inhibition to enhance proinflammatory cytokines and suppress IL-10 production. In contrast, inhibition of PI3K enhanced this regulatory ability of JAK3 in LPS-stimulated monocytes. At the transcriptional level, JAK3 knockout lead to the increased phosphorylation of STATs that could be attenuated by neutralization of de novo inflammatory cytokines. JAK3 inhibition exhibited a GSK3 activity-dependent ability to enhance phosphorylation levels and DNA binding of NF-κB p65. Moreover, JAK3 inhibition correlated with an increased CD4+ T cell response. Additionally, higher neutrophil infiltration, IL-17 expression, and intestinal epithelium erosion were observed in JAK3 knockout mice. These findings demonstrate the negative regulatory function of JAK3 and elucidate the signaling pathway by which JAK3 differentially regulates TLR-mediated inflammatory cytokine production in innate immune cells.

MicroRNA-645, up-regulated in human adencarcinoma of gastric esophageal junction, inhibits apoptosis by targeting tumor suppressor IFIT2

BackgroundAn increasing body of evidence indicates that miRNAs have a critical role in carcinogenesis and cancer progression; however, the role of miRNAs in the tumorigenesis of adencarcinoma of gastric esophageal junction (AGEJ) remains largely unclear.MethodsThe SGC7901 and BGC-823 gastric cancer cell lines were used. The expressions of miR-645 and IFIT2 (Interferon-induced protein with tetratricopeptide repeats 2) were examined by qRT-PCR, The expressions of IFIT2 was examined by western blotting and immunohistochemistry assay. The cell apoptosis was determined by FACS. MiR-645 inhibitor, mimics and plasmid-IFIT2 transfections were performed to study the loss- and gain-function. Caspase-3/7 activity was examined by caspase-3/7 assay.ResultsIn the present study, we have reported an increased expression of miR-645 in AGEJ clinical specimens compared with paired non-cancerous tissues. We also observed a significant miR-645 up-regulation in two gastric cancer (GC) cell lines, SGC7901 and BGC-823, which were used as cell models because there was no available AGEJ cell lines established to date. We found that inhibition of miR-645 could sensitize dramatically SGC7901 and BGC-823 cells to both serum starvation– and chemotherapeutic drug–induced apoptosis by up-regulating IFIT2, a mediator of apoptosis via a mitochondrial pathway, with a potential binding site for miR-645 in its mRNA’s 3′UTR. Further investigation exhibited that IFIT2 expression decreases in SGC7901 and BGC-823 cells and AGEJ tissues. IFIT2 ectopic expression leads to promotion of cell apoptosis, indicating that IFIT2 may function as a suppressor in the development of AGEJ. Furthermore, inhibition of miR-645 induces up-regulation of IFIT2 and increased caspase-3/7 activity compared with control groups.ConclusionsOur data suggest that miR-645 functions as an oncogene in human AGEJ by, at least partially through, targeting IFIT2.

Clinical significance of combined detection of human papilloma virus infection and human telomerase RNA component gene amplification in patients with squamous cell carcinoma of the esophagus in northern China

BackgroundThe aim of the study was to test for human papilloma virus (HPV) infection and human telomerase RNA component (hTERC) gene amplification in tissues derived from esophageal cancer, in esophagus displaying atypical hyperplasia and in normal tissue, and to analyze the relationship between them and discuss whether HPV infection and hTERC gene amplification play a role in the duration of survival of esophageal cancer patients.MethodsTo test for HPV infection, surface plasma resonance was used after extracting and subjecting the DNA to PCR amplification. Measurement of hTERC gene amplification was performed by the fluorescence in situ hybridization technique.ResultsThe rates of HPV infection in the normal group, the atypical esophageal hyperplasia group and the cancer group were 0% (0/40), 10.00% (1/10) and 20.65% (19/92), respectively, with a statistically significant difference of P < 0.01. The hTERC gene amplification rate in normal tissue, grade I atypical hyperplastic tissue, grade II/III atypical hyperplastic tissue and esophageal cancer tissue were 0% (0/89), 15.38% (4/26), 47.06% (8/17) and 89.13% (82/92), respectively, with a statistically significant difference of P < 0.01. On follow-up of 92 patients, survival curves of the HPV-positive and HPV-negative groups were not significantly different (P > 0.05). Survival curves of the hTERC gene amplification-positive and hTERC gene amplification-negative groups were statistically significant (P < 0.05). A matching chi-square test showed that there was no correlation between HPV infection and hTERC gene amplification (P > 0.05).ConclusionHPV infection may be one of many factors contributing to the development of esophageal cancer, but it does not influence prognosis. Amplification of the hTERC gene appears to influence certain features associated with postoperative survival in esophageal carcinoma patients.

Detection and Clinical Significance of Lymph Node Micrometastasis in Gastric Cardia Adenocarcinoma

OBJECTIVES: Lymph node micro metastasis was investigated in gastric cardia adenocarcinoma (GCA) patients without lymph node metastasis on routine pathological examination. The relationship between micrometastasis and clinicopathological features was also evaluated. METHODS: A total of 349 lymph nodes were obtained from 45 patients with GCA. Micrometastases were detected by immunohistochemical staining for the markers cytokeratin 19 (CK19) and CD44 variant 6 (CD44v6). RESULTS: A total of 33 lymph nodes (9.5%) from 15 patients (33.3%) were positive for CK19. Of these, 27 lymph nodes (7.7%) from 12 patients (26.7%) were also positive for CD44v6. Micrometastasis was significantly related to depth of tumour invasion and Lauren classification (intestinal or diffuse). The recurrence rate was significantly higher and 2-year survival rate significantly lower in patients with than in those without lymph node micrometastasis, showing the necessity of detecting micrometastasis in GCA patients who test negative for lymph node metastasis on routine examination. CONCLUSION: CK19 and CD44v6 were shown to be good markers for micrometastasis detection.

Prevalence and age, gender and geographical area distribution of esophageal squamous cell carcinomas in North China from 1985 to 2006.

OBJECTIVE To establish the prevalence and distribution profile of esophageal squamous cell carcinomas (ESCCs) over a 22-yr period in North China. METHODS Using endoscopy for primary diagnosis and histological analysis for the further confirmation, a total of 74,854 ESCC patients aged 20-89 between January 1985 and December 2006 were investigated to analyze the epidemiological profile including prevalence rates, distribution of age-of-onset, gender and geographical area of ESCC in Luoyang, the highest incidence area of North China. RESULTS A total of 4092 cases of ESCC were finally diagnosed among 74,854 patients who had their first endoscopies. The prevalence among males was higher than that among females (p<0.01), resulting in an overall male:female OR of 1.2 (95%CI, 1.2-1.3). The prevalence in rural areas was higher than in urban areas (p<0.01), resulting in an overall rural:urban OR of 2.6 (95%CI, 2.4-2.9). The rural:urban ORs and the 95% CI increased continuously from 2.6, 2.3-3.0 to 2.7, 2.2-3.3, respectively, for 4 consecutive periods during the 22-yr study period. Moreover, the median age of onset among females was higher than that among males (p<0.01). For both sexes and in both areas, the prevalence rates declined and the median age of onset rose for 4 consecutive periods in the 22-yrs time frame (p<0.01). CONCLUSIONS [corrected] These data reveal the epidemiological profile of ESCC in the area of North China, and suggest that urban areas and rural people account for a growing proportion of the ESCC patients although the prevalence of ESCC significantly declined and the median age-of-onset postponed over the 22-yrs period. Moreover, the prevalence status of ESCC in rural areas also underlines the need for public health initiatives aimed at reducing risk factors of this fatal disease.

Prognostic significance of PD-L1 expression in patients with gastric cancer in east asia: a meta-analysis

The overexpression of programmed cell death-ligand 1(PD-L1) has been observed in gastric cancer (GC). However, whether the expression of PD-L1 in tumor cells or blood serum is associated with the prognosis of patients with GC remains unclear. Therefore, we performed a meta-analysis to evaluate the prognostic significance of PD-L1 expression in GC. Electronic databases were searched systematically. Studies that met the inclusion criteria were included in the meta-analysis. Data concerning the hazard ratio (HR) for overall survival and disease-free survival with a 95% confidence interval (CI) according to the expression status of PD-L1 evaluated by immunohistochemistry or enzyme-linked immunosorbent assay were extracted. The data were analyzed using a random effects model. Subgroup analyses were proposed. Our results showed that eight studies with 950 patients met the inclusion criteria and were included in the meta-analysis. The pooled HR for overall survival indicated that patients with PD-L1-positive expression had significantly shorter survival time compared with the PD-L1-negative group (HR 1.60, 95% CI 1.09–2.36, P=0.012). The pooled HR for disease-free survival demonstrated that the difference between the two groups was not statistically significant (HR 1.02, 95% CI 0.32–3.20, P=0.98). In conclusion, our results indicate that the evaluation of PD-L1 overexpression in GC tissue or blood serum may be useful in the future as a novel prognostic factor.

Midkine promotes perineural invasion in human pancreatic cancer

AIM To investigate midkine (MK) and syndecan-3 protein expression in pancreatic cancer by immunohistochemistry, and to analyze their correlation with clinicopathological features, perineural invasion, and prognosis. METHODS Pancreatic cancer tissues (including adequately sized tumor tissue samples and tissue samples taken from areas less than 2.0 cm around the tumor) were taken from 42 patients who were undergoing a partial duodenopancreatectomy. MK and syndecan-3 proteins were detected by immunohistochemistry using a standardized streptavidin-peroxidase method, and analyzed for their correlation with clinicopathological features, perineural invasion, and prognosis. Associations of neural invasion with aggressive characteristics of pancreatic cancer and the presence of perineural invasion were assessed by two independent observers blinded to the patient status. RESULTS MK and syndecan-3 were found in 26 (61.9%) and 24 (57.1%) specimens, respectively. MK and syndecan-3 expression was associated with perineural invasion (P = 0.018 and 0.031, respectively). High MK expression was closely associated with advanced tumor, node and metastasis stage (P = 0.008), lymph node metastasis (P = 0.042), and decreased postoperative survival at 3 years (51.0% vs 21.8%, P = 0.001). Syndecan-3 levels were correlated with tumor size (P = 0.028). Patients who were syndecan-3 negative had a higher cumulative survival rate than those who were positive, but the difference was not significant (44.0% vs 23.0%, P > 0.05). CONCLUSION MK and syndecan-3 are frequently expressed in pancreatic cancer and associated with perineural invasion. High expression of MK and syndecan-3 may contribute to the highly perineural invasion and poor prognosis of human pancreatic cancer.