Genetic susceptibility factors on genes involved in the steroid hormone biosynthesis pathway and progesterone receptor for gastric cancer risk

Metabolomics-based discovery of XHP as a CYP3A4 inhibitor against pancreatic cancer

Background: Xihuang Wan (XHW), a purgative and detoxifying agent, is commonly utilized in modern medicine as a treatment and adjuvant therapy for various malignancies, including breast cancer, liver cancer, and lung cancer. A clinical study demonstrated the potential usefulness of the combination of XHW and gemcitabine as a therapy for pancreatic cancer (PC), indicating that XHW’s broad-spectrum antitumor herbal combination could be beneficial in the treatment of PC. However, the precise therapeutic efficacy of XHW in treating pancreatic cancer remains uncertain.

Aim: This study assessed the biological activity of XHW by optimizing the therapeutic concentration of XHW (Xihuang pills, XHP). We performed cell culture and developed an animal test model to determine whether XHP can inhibit pancreatic cancer (PC). We also applied the well-known widely targeted metabolomics analysis and conducted specific experiments to assess the feasibility of our method in PC therapy.

Materials and Methods: We used UPLC/Q-TOF-MS to test XHP values to set up therapeutic concentrations for the in vivo test model. SW1990 pancreatic cancer cells were cultured to check the effect the anti-cancer effects of XHP by general in vitro cell analyses including CCK-8, Hoechst 33258, and flow cytometry. To develop the animal model, a solid tumor was subcutaneously formed on a mouse model of PC and assessed by immunohistochemistry and TUNEL apoptosis assay. We also applied the widely targeted metabolomics method following Western blot and RT-PCR to evaluate multiple metabolites to check the therapeutic effect of XHP in our cancer test model.

Results: Quantified analysis from UPLC/Q-TOF-MS showed the presence of the following components of XHP: 11-carbonyl-β-acetyl-boswellic acid (AKBA), 11-carbonyl-β-boswellic acid (KBA), 4-methylene-2,8,8-trimethyl-2-vinyl-bicyclo [5.2.0]nonane, and (1S-endo)-2-methyl-3-methylene-2-(4-methyl-3-3-pentenyl)-bicyclo [2.2.1heptane]. The results of the cell culture experiments demonstrated that XHP suppressed the growth of SW1990 PC cells by enhancing apoptosis. The results of the animal model tests also indicated the suppression effect of XHP on tumor growth. Furthermore, the result of the widely targeted metabolomics analysis showed that the steroid hormone biosynthesis metabolic pathway was a critical factor in the anti-PC effect of XHP in the animal model. Moreover, Western blot and RT-PCR analyses revealed XHP downregulated CYP3A4 expression as an applicable targeted therapeutic approach.

Conclusion: The results of this study demonstrated the potential of XHP in therapeutic applications in PC. Moreover, the widely targeted metabolomics method revealed CYP3A4 is a potential therapeutic target of XHP in PC control. These findings provide a high level of confidence that XHP significantly acts as a CYP3A4 inhibitor in anti-cancer therapeutic applications.

Genetic variants in CYP2B6 and HSD17B12 associated with risk of squamous cell carcinoma of the head and neck

Polycyclic aromatic hydrocarbons (PAH) and tobacco-specific nitrosamines (TSNA) metabolism-related genes play an important role in the development of cancers. We assessed the associations of genetic variants in genes involved in the metabolism of PAHs and TSNA with risk of squamous cell carcinoma of the head and neck (SCCHN) in European populations using two published genome-wide association study datasets. In the single-locus analysis, we identified two SNPs (rs145533669 and rs35246205) in CYP2B6 to be associated with risk of SCCHN (P = 1.57 × 10-4 and .004, respectively), two SNPs (EPHX1 rs117522494 and CYP2B6 rs145533669) to be associated with risk of oropharyngeal cancer (P = .001 and .004, respectively), and one SNP (rs4359199 in HSD17B12) to be associated with risk of oral cancer (P = .006). A significant interaction effect was found between rs4359199 and drinking status on risks of SCCHN and oropharyngeal cancer (P < .05). eQTL and sQTL analyzes revealed that two SNPs (CYP2B6 rs35246205 and HSD17B12 rs4359199) were correlated with alternative splicing or mRNA expression levels of the corresponding genes in liver cells (P < .05 for both). In silico functional annotation suggested that these two SNPs may regulate mRNA expression by affecting the binding of transcription factors. Results from phenome-wide association studies presented significant associations between these genes and risks of other cancers, smoking behavior and alcohol dependence (P < .05). Thus, our study provided some insight into the underlying genetic mechanism of head and neck cancer, which warrants future functional validation.

Role of single nucleotide polymorphisms of the HSD3B1 gene (rs6203 and rs33937873) in the prediction of prostate cancer risk

3-β-hydroxysteroid dehydrogenase 1 (HSD3B1) is shown to affect dihydrotestosterone level in prostatic tissue which is a risk factor for prostate cancer (PC). The present study aimed to determine whether rs33937873 (G313A) and rs6203 (C338T) single nucleotide polymorphisms (SNP) in HSD3B1 gene was a potential risk factor for PC susceptibility and can predict the recurrence of PC in Egyptian patients. A total of 186 Egyptian patients were selected with incident primary PC and compared with 180 age healthy controls. The frequencies and the main effect of rs33937873 and rs6203 in HSD3B1 were compared and investigated between the patients and control using genotyping technique and statistical analysis. The mutant GA genotype of G313A in rs33937873 SNP was considered as an independent risk for PC in the multivariate regression analysis [odds ratio (OR)=2.7, 95% confidence intervals (CI): 1.2-5.5, P=0.01] together with positive history of hypertension (HTN) (OR=6.2, 95% CI: 3.2-12.1, P=0.0001) and begin prostatic hyperplasia (BPH; OR=8.9, 95% CI: 4.5-17.5, P=0.0001). Conversely, in rs6203 (C338T), C allele is considered as major risk allele in the development of PC (OR=1.8, 95% CI: 1.3-2.4, P=0.0003). The univariate logistic regression analyses indicated that CC genotype of rs6203 was a PC risk factor (OR=1.9, 95% CI: 1.3-2.9, P=0.002). In addition, the frequency of the A-C haplotype established by rs33937873-rs6203 was also significantly higher for PC (P=0.013). The predication of PC recurrence was associated only with positive family history (OR=7.7, 95% CI: 2.3-25.9, P=0.001) and not for The G313A and C338T SNPs. These results suggested that the two HSD3B1 polymorphisms rs33937873 and rs6203 may modify the risk of PC, particularly among patients with HTN and history of BPH, suggesting them as prominent future markers for prediction of PC risk.

A urine and serum metabolomics study of gastroesophageal reflux disease in TCM syndrome differentiation using UPLC-Q-TOF/MS

Gastroesophageal reflux disease (GERD) is a common, chronic and complex upper gastrointestinal disease. In Traditional Chinese medicine (TCM) theory, GERD is classified into two main types: stagnant heat of liver and stomach (SHLS) and deficient cold of spleen and stomach (DCSS). The discovery and evaluation of potential biomarkers for different syndrome types of GERD may contribute to comprehend specific molecular mechanism and identify new targets for diagnosis and appropriate management. In our study, 60 subjects including 40 GERD patients (20 SHLS and 20 DCSS) and 20 healthy controls were recruited, and the serum and urine metabolic profiles from untargeted liquid chromatography coupled to mass spectrometry (LC-MS) metabolomics approach were obtained. Finally 38 biomarkers associated with disease were identified and 9 metabolic pathways were enriched. The most enriched pathways were amino acid metabolism, steroid hormone biosynthesis, glycerophospholipid metabolism, sphingolipid metabolism and TCA cycle. According to the area under curve (AUC) value, we propose a cohort of three metabolites from urine and serum samples as promising biomarkers for TCM syndrome differentiation of GERD, which are prolylhydroxyproline, glycitein-4'-O-glucuronide, capsianoside I in urine and neuAcalpha2-3Galbeta-Cer (d18:1/16:0), sphinganine, arachidonic acid in serum. The cumulative AUC value of merged biomarkers in urine and serum was 0.979 (95%CI 0.927-1) and 0.842 (95%CI 0.704-0.980), respectively. The results indicated that LC-MS based metabolomic profiling method might be an effective and promising tool on further pathogenesis discovering of GERD. The findings provided new strategy for the diagnosis of GERD TCM syndrome differentiation in clinic.

Computational Functional Genomics-Based AmpliSeq™ Panel for Next-Generation Sequencing of Key Genes of Pain

The genetic background of pain is becoming increasingly well understood, which opens up possibilities for predicting the individual risk of persistent pain and the use of tailored therapies adapted to the variant pattern of the patient's pain-relevant genes. The individual variant pattern of pain-relevant genes is accessible via next-generation sequencing, although the analysis of all "pain genes" would be expensive. Here, we report on the development of a cost-effective next generation sequencing-based pain-genotyping assay comprising the development of a customized AmpliSeq™ panel and bioinformatics approaches that condensate the genetic information of pain by identifying the most representative genes. The panel includes 29 key genes that have been shown to cover 70% of the biological functions exerted by a list of 540 so-called "pain genes" derived from transgenic mice experiments. These were supplemented by 43 additional genes that had been independently proposed as relevant for persistent pain. The functional genomics covered by the resulting 72 genes is particularly represented by mitogen-activated protein kinase of extracellular signal-regulated kinase and cytokine production and secretion. The present genotyping assay was established in 61 subjects of Caucasian ethnicity and investigates the functional role of the selected genes in the context of the known genetic architecture of pain without seeking functional associations for pain. The assay identified a total of 691 genetic variants, of which many have reports for a clinical relevance for pain or in another context. The assay is applicable for small to large-scale experimental setups at contemporary genotyping costs.

A comprehensive analysis of the microbiota composition and gene expression in colorectal cancer

BACKGROUND

The dysregulation of gut microbiota is pivotal in colorectal carcinogenesis. Meanwhile, altered gut microbiome may affect the development of intestinal diseases through interaction with the host genes. However, the synergy between the altered gut microbiota composition and differential expression of specific genes in colorectal cancer (CRC) remains elusive. Thus, we integrated the data from 16S rRNA gene sequences and RNA sequences to investigate the potential relationship between genes and gut microbes in patients with CRC.

RESULTS

Compared with normal samples, the presence of Proteobacteria and Fusobacteria increased considerably in CRC samples; conversely, the abundance of Firmicutes and Spirochaetes decreased markedly. In particular, the genera Fusobacterium, Catenibacterium, and Shewanella were only detected in tumor samples. Meanwhile, a closely interaction between Butyricimonas and Clostridium was observed in the microbiome network. Furthermore, a total of 246 (differentially expressed genes) DEGs were identified between tumor and normal tissues. Both DEGs and microbiota were involved in bile secretion and steroid hormone biosynthesis pathways. Finally, genes like cytochrome P450 family 3 subfamily A member 4 (CYP3A4) and ATP binding cassette subfamily G member 2 (ABCG2) enriched in these two pathways were connected with the prognosis of CRC, and CRC patients with low expression level of CYP3A4 and ABCG2 had longer survival time.

CONCLUSION

Identifying the complicated interaction between gut microbiota and the DEGs contributed to further understand the pathogenesis of CRC, and these findings might enable better diagnosis and treatment of CRC patients.

Role of hydroxysteroid (17beta) dehydrogenase type 1 in reproductive tissues and hormone-dependent diseases

Abnormal synthesis and metabolism of sex steroids is involved in the pathogenesis of various human diseases, such as endometriosis and cancers arising from the breast and uterus. Steroid biosynthesis is a multistep enzymatic process proceeding from cholesterol to highly active sex steroids via different intermediates. Human Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) enzyme shows a high capacity to produce the highly active estrogen, estradiol, from a precursor hormone, estrone. However, the enzyme may also play a role in other steps of the steroid biosynthesis pathway. In this article, we have reviewed the literature on HSD17B1, and summarize the role of the enzyme in hormone-dependent diseases in women as evidenced by preclinical studies.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Risk Factors for Gastric Cancer: A Systematic Review

Objective: Gastric cancer is one of the leading causes of death worldwide, with many influences contributing to the disease. The aim of this study was to identify the most important risk factors. Methods: This study was conducted in 2017 with a structured overview in the Science Directe, Scopus, PubMed, Cochrane, Web of Science (ISI) databases. In the first step, articles were extracted based on their titles and abstracts; the quality of 43 articles was evaluated using the STORBE tool. Inclusion criteria were studies carried out on human, English language (first step), year of the study and the study type (second step). Results: Finally, 1,381 articles were found, of which 1,269 were excluded in primary and secondary screening. In reviewing the references of the remaining 44 papers, 4 studies were added. Finally, 43 articles were selected for the quality assessment process. A total of 52 risk factors for gastric cancer were identified and classified into nine important categories: diet, lifestyle, genetic predisposition, family history, treatment and medical conditions, infections, demographic characteristics, occupational exposures and ionizing radiation’. Conclusion: Several environmental and genetic factors are involved in the development of gastric cancer. Regarding the role of changes in ‘diet and lifestyle’, considering appropriate nutrition and improving the level of education and awareness of people is vital for early diagnosis and timely treatment of this disease, especially in people with a family history and genetic predisposition.

Cholesterol import and steroidogenesis are biosignatures for gastric cancer patient survival

Androgens, estrogens, progesterone and related signals are reported to be involved in the pathology of gastric cancer. However, varied conclusions exist based on serum hormone levels, receptor expressions, and in vitro or in vivo studies. This report used a web-based gene survival analyzer to evaluate biochemical processes, including cholesterol importing via lipoprotein/receptors (L/R route), steroidogenic enzymes, and steroid receptors, in gastric cancer patients prognosis. The sex hormone receptors (androgen receptor, progesterone receptor, and estrogen receptor ESR1 or ESR2), L/R route (low/high-density lipoprotein receptors, LDLR/LRP6/SR-B1 and lipoprotein lipase, LPL) and steroidogenic enzymes (CYP11A1, HSD3B1, CYP17, HSD17B1, HSD3B1, CYP19A1 and SRD5A1) were associated with 5-year survival of gastric cancer patients. The AR, PR, ESR1 and ESR2 are progression promoters, as are the L/R route LDLR, LRP6, SR-B1 and LPL. It was found that CYP11A1, HSD3B1, CYP17, HSD17B1 and CYP19A1 promote progression, but dihydrotestosterone (DHT) converting enzyme SRD5A1 suppresses progression. Analyzing steroidogenic lipidome with a hazard ratio score algorithm found that CYP19A1 is the progression confounder in surgery, HER2 positive or negative patients. Finally, in the other patient cohort from TCGA, CYP19A1 was expressed higher in the tumor compared to that in normal counterparts, and also promoted progression. Lastly, exemestrane (type II aromatase inhibitor) dramatically suppress GCa cell growth in pharmacological tolerable doses in vitro. This work depicts a route-specific outside-in delivery of cholesterol to promote disease progression, implicating a host-to-tumor macroenvironmental regulation. The result indicating lipoprotein-mediated cholesterol entry and steroidogenesis are GCa progression biosignatures. And the exemestrane clinical trial in GCa patients of unmet medical needs is suggested.

ZnRF3 Induces Apoptosis of Gastric Cancer Cells by Antagonizing Wnt and Hedgehog Signaling

A large proportion of malignant cancers of the stomach are gastric adenocarcinoma type. In spite of many studies, the molecular basis for this cancer is still unclear. Deregulated cell proliferative signaling via Wnt/β-catenin and Hedgehog pathways is considered important in the pathogenesis of many cancers including the gastric cancer. Recent studies identified ZnRF3 protein, which is a E3-ubiquitin ligase and which is either deleted or mutated in cancers, to inhibit Wnt signaling. However, the significance of ZnRF3 in the control of gastric cancer and whether it also regulates Hedgehog signaling pathway, is not known. In the present study, we assessed the expression of ZnRF3 in gastric tumors and paracancerous tissues from 58 patients (44 male and 14 female) of different ages and related this to patient survival. We observed a clear relationship between ZnRF3 expression in paracancerous tissue and tumor size. Also, ZnRF3 expression was much higher in tumors from aged patients. Male patients showed higher mortality than the females. Mechanistic studies using normal gastric cells (GES1) and gastric cancer cells (MGC-803) infected with either AdZnRF3 or AdGFP viral vectors, revealed that ZnRF3 overexpression causes significantly more apoptosis and lowered proliferation of cancer cells. ZnRF3 overexpression led to greatly reduced levels of Lgr5, a component of Wnt signaling and also Gli1, a component of Hedgehog signaling. Thus, ZnRF3 negatively influences both the Wnt and Hedgehog proliferative pathways, and probably this way it negatively regulates cancer progression. These results suggest the importance of normal ZnRF3 function in checking the progression of cancer cell growth and indicate that a lack of this protein can lead to poorer clinical outcomes for gastric cancer patients.

17β-Estradiol in the systemic circulation derives mainly from the parietal cells in cholestatic female rats

PURPOSE

Estrogenic symptoms of liver disease patients including biliary tract disorder with high frequency is observed in clinical cases. However, the origin of 17β-estradiol which is abundant enough to cause symptoms remains uncertain. In male rats, it has been reported that the parietal cells which have an abundance of aromatase-synthesized 17β-estradiol, and a part of 17β-estradiol secreted into the portal vein, may flow into the systemic circulation under a pathophysiological condition of the liver including bile duct ligation (BDL). The aim of this study is to reveal the origin of 17β-estradiol increment in female rats and to investigate the effect of BDL on the ovary during the estrus cycle.

METHODS

Wistar female rats were used, and the common bile duct was ligated twice and transected completely at 7 days before termination. Serum portal venous and arterial 17β-estradiol levels, Cyp19a1 expressions, aromatase protein levels, and estrogen receptor (ER) α levels in the liver were measured during the estrus cycle.

RESULTS

Both arterial and portal venous 17β-estradiol levels increased 2.9 times at proestrus and maintained constant levels during the cycle. The expression of Cyp19a1 and aromatase protein in the stomach maintained constant levels, and significantly decreased during the estrus cycle in the ovary. Hepatic ERα protein and Esr1 expressions decrease by BDL in all stages.

CONCLUSIONS

These results suggest that the increment of serum 17β-estradiol levels in obstructive cholestasis induced by BDL is derived from 17β-estradiol secreted from the parietal cells in females as well as males.

Transcript level of AKR1C3 is down-regulated in gastric cancer

Steroid hormones have been shown to play a role in gastric carcinogenesis. Large amounts of steroid hormones are locally produced in the peripheral tissues of both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by the AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism, and its expression was found to be deregulated in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues, and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased levels of AKR1C3 transcript (p < 0.0001) and protein (p = 0.0021) in GC tissues compared with the adjacent, apparently histopathologically normal, mucosa. Lower levels of AKR1C3 transcript were observed in diffuse and intestinal types of GC, whereas AKR1C3 protein levels were decreased in tumors with multisite localization, in diffuse histological type, T3, T4, and G3 grades. We also determined the effect of the histone deacetylase inhibitor sodium butyrate (NaBu) on AKR1C3 expression in EPG 85-257 and HGC-27 GC cell lines. We found that NaBu elevates the levels of both AKR1C3 transcript and protein in the cell lines we investigated. Together, our results suggest that decreased expression of AKR1C3 may be involved in development of GC and can be restored by NaBu.

Amerindian genetic ancestry and INDEL polymorphisms associated with susceptibility of childhood B-cell Leukemia in an admixed population from the Brazilian Amazon

Acute lymphoblastic leukemia (ALL) is a malignant tumor common in children. Studies of genetic susceptibility to cancer using biallelic insertion/deletion (INDEL) type polymorphisms associated with cancer development pathways may help to clarify etymology of ALL. In this study, we investigate the role of eight functional INDEL polymorphisms and influence of genetic ancestry to B-cell ALL susceptibility in children of Brazilian Amazon population, which has a high degree of inter-ethnic admixture. Ancestry analysis was estimated using a panel of 48 autosomal ancestry informative markers. 130 B-cell ALL patients and 125 healthy controls were included in this study. The odds ratios and 95% confidence intervals were adjusted for confounders. The results indicated an association between the investigated INDEL polymorphisms in CASP8 (rs3834129), CYP19A1 (rs11575899) e XRCC1 (rs3213239) genes in the development of B-cell ALL. The carriers of Insertion/Insertion (Ins/Ins) genotype of the polymorphism in CASP8 gene presented reduced chances of developing B-cell ALL (P=0.001; OR=0.353; 95% CI=0.192-0.651). The Deletion/Deletion (Del/Del) genotype of the polymorphism in CYP19A1 gene was associated to a lower chance of developing B-cell ALL (P=3.35×10-6; OR=0.121; 95% CI=0.050-0.295), while Del/Del genotype of the polymorphism in XRCC1 gene was associated to a higher chance of developing B-cell ALL (P=2.01×10-4; OR=6.559; 95% CI=2.433-17.681). We also found that Amerindian ancestry correlates with the risk of B-cell ALL. For each increase of 10% in the Amerindian ancestry results in 1.4-fold chances of developing B-cell ALL (OR=1.406; 95% IC=1.123-1.761), while each increase of 10% in the European ancestry presents a protection effect in the development of B-cell ALL (OR=0.666; 95% IC=0.536-0.827). The results suggest that genetic factors influence leukemogenesis and might be explored in the stratification of B-cell ALL risk in admixed populations.

Screening of susceptibility genes and multi-gene risk analysis in gastric cancer

The aim of the study was to explore the relations between the genetic polymorphism and the susceptibility to the gastric cancer in Chinese Han population, and to analyze the multi-genes risk in the development of gastric carcinoma. A case-control study of 1:1 matching was performed on 564 individuals with primary gastric carcinoma in Nanjing, China. The genotypes of CYP2E1, GSTMl, GSTTl, NAT2, ALDH2, MTHFR, XRCCl, IL-1β, VDR, and TNF were detected by molecular biological techniques (PCR-RFLP and AS-PCR). Sole gene and gene-gene interactions were analyzed using Logistic regression model. The effect of multi-genes on gastric carcinoma was analyzed using multi-gene risk analysis model, which focused on the effect of multi-gene interaction on the development of gastric carcinoma. The genotypes involved in the susceptibility of gastric carcinoma were CYP2E1(c1/c1), NAT2M1(T/T), NAT2M2(A/A), XRCC1194(T/T), NAT2 phenotype (slow acetylator), MTHFR1298(A/C), and VDR TaqI(T/T), respectively. Multi-gene risk analysis model was introduced to analyze the effect of these genes on the gastric carcinoma. The results showed that there was a strong relation between odds ratio (OR) value of polygene combination and the gene frequency. With the increase of susceptibility gene frequency, the risk distribution curve of gastric carcinoma would shift to a more dangerous phase and exhibit a quantitative relation. Our results demonstrated that the OR of each gene can be utilized as an index to assess the effect of multiple susceptible genes on the occurrence of gastric carcinoma.

Association analysis of ERBB2 amplicon genetic polymorphisms and STARD3 expression with risk of gastric cancer in the Chinese population

The purpose of this study was to investigate whether risk of gastric cancer (GC) was associated with single nucleotide polymorphisms (SNPs) in a gene cluster on the chromosome 17q12-q21 (ERBB2 amplicon) in the Chinese Han population. We detected twenty-six SNPs in this gene cluster containing steroidogenic acute regulatory-related lipid transfer domain containing 3 (STARD3), protein phosphatase 1 regulatory subunit 1B (PPP1R1B/DARPP32), titin-cap (TCAP), per1-like domain containing 1(PERLD1/CAB2), human epidermal growth factor receptor-2 (ERBB2/HER2), zinc-finger protein subfamily 1A 3 (ZNFN1A3/IKZF3) and DNA topoisomerase 2-alpha (TOP2A) genes in 311 patients with GC and in 425 controls by Sequenom. We found no associations between genetic variations and GC risk. However, haplotype analysis implied that the haplotype CCCT of STARD3 (rs9972882, rs881844, rs11869286 and rs1877031) conferred a protective effect on the susceptibility to GC (P=0.043, odds ratio [OR]=0.805, 95% confidence intervals [95% CI]=0.643-0.992). The STARD3 rs1877031 TC genotype endued histogenesis of gastric mucinous adenocarcinoma and signet-ring cell carcinoma (P=0.021, OR=2.882, 95% CI=1.173-7.084). We examined the expression of STARD3 in 243 tumor tissues out of the 311 GC patients and 20 adjacent normal gastric tissues using immumohistochemical (IHC) analysis and tissue microarrays (TMA). The expression of STARD3 was observed in the gastric parietal cells and in gastric tumor tissues and significantly correlated with gender (P=0.004), alcohol drinking (P<0.001), tumor location (P=0.007), histological type (P=0.005) and differentiation (P=0.023) in GC. We concluded that the combined effect of haplotype CCCT of STARD3 might affect GC susceptibility. STARD3 expression might be related to the tumorigenesis of GC in the Chinese population.

Gastric cancer: epidemiologic aspects

A multifactorial and multistep model of gastric cancer (GC) is currently accepted, according to which different environmental and genetic factors are involved at different stages in the cancer process. The aim of this article is to review the most relevant information published on the relative contribution of genetic and environmental factors. Large meta-analyses confirmed the association between IL8, IL10, TNF-b, TP53 and PSCA, while genetic variation at different genes such as XPG, PLCE1, HFE, ERCC5, EZH2, DOC2, CYP19A1, ALDH2, and CDH1 have been reported to be associated with GC risk. Several microRNAs have also been associated with GC and their prognosis. Cohort studies have shown the association between GC and fruit, flavonoid, total antioxidant capacity, and green tea intake. Obesity was associated with cardia GC, heme iron intake from meat with GC risk. Several large meta-analyses have confirmed the positive association of GC with salt intake and pickled foods and the negative association with aspirin use.

ZNRF3 acts as a tumour suppressor by the Wnt signalling pathway in human gastric adenocarcinoma

E3 ubiquitin ligases regulate a variety of biological processes through the ubiquitin-proteasome system, together with ubiquitin activating enzyme E1 and ubiquitin-conjugating enzyme E2. Previous studies have demonstrated that zinc and ring finger 3 (ZNRF3), which belongs to the E3 ubiquitin ligases family is involved in the Wnt signalling pathway, which plays an important role in causing cancer. However, the expression and function of ZNRF3 in human gastric adenocarcinoma still remains unclear. Immunohistochemical and western blot analysis showed a significant down-regulation of ZNRF3 protein in gastric adenocarcinoma tissues compared with adjacent normal gastric tissues. In addition, there was a correlation between the down-regulation of ZNRF3 and poor tissue differentiation in gastric adenocarcinoma. To investigate the potential function of ZNRF3 in cell proliferation and apoptosis, a gastric cell line SGC7901 was employed. The over-expression of wild-type ZNRF3, which was accomplished by the transient transfection of recombinant pEGFP-ZNRF3 (or empty plasmids as control) into the cell line SGC7901, was confirmed by western blot analysis. Flow-cytometry-based and Cell Counting Kit-8 assays showed that over-expression of wt ZNRF3 induced apoptosis and suppressed proliferation. ZNRF3-overexpressing gastric cells displayed partly attenuated protein levels of beta-catenin and TCF-4 compared with those transfected with the empty plasmid. Our study demonstrates a novel gastric adenocarcinoma suppressor and reveals that ZNRF3 inhibits gastric cancer cell growth and promotes the cell apoptosis by affecting the Wnt/beta-catenin/TCF signalling pathway.