Cancer risk and chemoprevention in Chinese inflammatory bowel disease patients: a population-based cohort study.

Background and aim: Role of 5-aminosalicylic acid (5-ASA), statin and aspirin in reducing cancer risks in inflammatory bowel disease (IBD) remains controversial. We aimed to examine chemo-preventive effects of these drugs in all cancers in IBD in population-based setting.Methods: IBD patients diagnosed between 2000 and 2016 were identified from the Hong Kong IBD Registry and followed from IBD diagnosis until first cancer occurrence. Primary outcome was cancer development ≥6 months after IBD diagnosis. Adjusted hazard ratio (aHR) with 95% confidence interval (CI) was estimated with Cox proportional hazards model. Additional effects of statin and aspirin on chemoprevention were also assessed.Results: Amongst 2103 IBD patients (857 Crohn's disease, 1246 ulcerative colitis; mean age 40.0 ± 15.6; 60.3% male) with 16,856 person-years follow-up, 48 patients (2.3%) developed cancer. The 5-r, 10-r and 15-year (95% CI) cumulative incidence of cancer were 1% (0.6 - 1.5%), 2.8 (2.0 - 3.9%) and 4.8 (3.4 - 6.5%), respectively. Total 1891 (89.9%) and 222 (10.6%) patients have received one or more prescriptions of 5-ASA and statin respectively. In multivariable analysis adjusted for age, gender, smoking status, IBD type and use of other medications, use of 5-ASA or statin was not associated with a reduced risk of cancer development (5-ASA: aHR 1.22, 95% CI: 0.60-2.48, p = .593; statin: aHR 0.48, 95% CI: 0.14-1.59, p = .227). Adding aspirin was not associated with a lowered cancer risk (aHR 1.18, 95% CI: 0.32-4.35, p = .799).Conclusion: Use of 5-ASA was not associated with a lowered cancer risk in Chinese IBD patients. Addition of statin/aspirin provided no additional benefit.Key summaryInflammatory bowel diseases (IBD) including Crohn's disease and ulcerative colitis are associated with increased risk of both intestinal and extra- intestinal cancers.Various medications including 5-aminosalicylate acid (5-ASA), statins and aspirin have been studied for their chemoprevention effects. However, most studies focused on colorectal cancer only and showed conflicting evidence. No studies so far looked at the effects of these medications on all cancer development in IBD.The 5-, 10- and 15-year (95% confidence interval) cumulative incidence of cancer in Chinese IBD patients were 1 (0.6-1.5%), 2.8 (2.0-3.9%) and 4.8 (3.4-6.5%), respectively.Use of 5-ASA was not associated with a lowered cancer risk in Chinese IBD patients. Addition of statin/aspirin provided no additional benefit.

Secretin-dependent signals in the ventromedial hypothalamus regulate energy metabolism and bone homeostasis in mice.

Secretin, though originally discovered as a gut-derived hormone, is recently found to be abundantly expressed in the ventromedial hypothalamus, from which the central neural system controls satiety, energy metabolism, and bone homeostasis. However, the functional significance of secretin in the ventromedial hypothalamus remains unclear. Here we show that the loss of ventromedial hypothalamus-derived secretin leads to osteopenia in male and female mice, which is primarily induced by diminished cAMP response element-binding protein phosphorylation and upregulation in peripheral sympathetic activity. Moreover, the ventromedial hypothalamus-secretin inhibition also contributes to hyperphagia, dysregulated lipogenesis, and impaired thermogenesis, resulting in obesity in male and female mice. Conversely, overexpression of secretin in the ventromedial hypothalamus promotes bone mass accrual in mice of both sexes. Collectively, our findings identify an unappreciated secretin signaling in the central neural system for the regulation of energy and bone metabolism, which may serve as a new target for the clinical management of obesity and osteoporosis.

Epigenetic silencing of a proapoptotic cell adhesion molecule, the immunoglobulin superfamily member IGSF4, by promoter CpG methylation protects Hodgkin lymphoma cells from apoptosis.

The malignant Hodgkin/Reed-Sternberg (HRS) cells of Hodgkin lymphoma (HL) are believed to derive from germinal center (GC) B cells, but lack expression of a functional B cell receptor. As apoptosis is the normal fate of B-cell receptor-negative GC B cells, mechanisms that abrogate apoptosis are thus critical in HL development, such as epigenetic disruption of certain pro-apoptotic cancer genes including tumor suppressor genes. Identifying methylated genes elucidates oncogenic mechanisms and provides valuable biomarkers; therefore, we performed a chemical epigenetic screening for methylated genes in HL through pharmacological demethylation and expression profiling. IGSF4/CADM1/TSLC1, a pro-apoptotic cell adhesion molecule of the immunoglobulin superfamily, was identified together with other methylated targets. In contrast to its expression in normal GC B cells, IGSF4 was down-regulated and methylated in HL cell lines, most primary HL, and microdissected HRS cells of 3/5 cases, but not in normal peripheral blood mononuclear cells and seldom in normal lymph nodes. We also detected IGSF4 methylation in sera of 14/18 (78%) HL patients but seldom in normal sera. Ectopic IGSF4 expression decreased HL cells survival and increased their sensitivity to apoptosis. IGSF4 induction that normally follows heat shock stress treatment was also abrogated in methylated lymphoma cells. Thus, our data demonstrate that IGSF4 silencing by CpG methylation provides an anti-apoptotic signal to HRS cells important in HL pathogenesis.

Epidemiology and Natural History of Elderly-onset Inflammatory Bowel Disease: Results From a Territory-wide Hong Kong IBD Registry.

BACKGROUND: Elderly-onset inflammatory bowel disease [IBD], defined as age ≥60 at diagnosis, is increasing worldwide. We aimed to compare clinical characteristics and natural history of elderly-onset IBD patients with those of adult-onset IBD patients. METHODS: Patients with a confirmed diagnosis of IBD from 1981 to 2016 were identified from a territory-wide Hong Kong IBD registry involving 13 hospitals. Demographics, comorbidities, clinical features, and outcomes of elderly-onset IBD patients were compared with those of adult-onset IBD patients. RESULTS: A total of 2413 patients were identified, of whom 270 [11.2%] had elderly-onset IBD. Median follow-up duration was 111 months (interquartile range [IQR]: 68-165 months). Ratio of ulcerative colitis [UC]: Crohn's disease [CD] was higher in elderly-onset IBD than in adult-onset IBD patients [3.82:1 vs 1.39:1; p <0.001]. Elderly-onset CD had less perianal involvement [5.4% vs 25.4%; p <0.001] than adult-onset CD. Elderly-onset IBD patients had significantly lower cumulative use of immunomodulators [p = 0.001] and biologics [p = 0.04]. Elderly-onset IBD was associated with higher risks of: cytomegalovirus colitis (odds ratio [OR]: 3.07; 95% confidence interval [CI] 1.92-4.89; p <0.001); herpes zoster [OR: 2.42; 95% CI 1.22-4.80; p = 0.12]; and all cancer development [hazard ratio: 2.97; 95% CI 1.84-4.79; p <0.001]. They also had increased number of overall hospitalisations [OR: 1.14; 95% CI 1.09-1.20; p <0.001], infections-related hospitalisation [OR: 1.87; 95% CI 1.47-2.38; p <0.001], and IBD-related hospitalisation [OR: 1.09; 95% CI 1.04- 1.15; p = 0.001] compared with adult-onset IBD patients. CONCLUSIONS: Elderly-onset IBD was associated with increased risk of infections and cancer development, and increased infection- and IBD-related hospitalisations. Specific therapeutic strategies to target this special population are needed.

Aberrant promoter methylation of DLEC1, a critical 3p22 tumor suppressor for renal cell carcinoma, is associated with more advanced tumor stage.

PURPOSE: Identifying tumor suppressor genes silenced by promoter CpG methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic biomarkers for early cancer detection. DLEC1 is located at 3p22.3, a critical tumor suppressor gene locus for renal cell carcinoma. We explored its epigenetic alteration in renal cell carcinoma and possible clinicopathological association. MATERIALS AND METHODS: We examined DLEC1 expression and methylation by semiquantitative reverse transcriptase and methylation specific polymerase chain reaction in 9 renal cell carcinoma cell lines and 81 primary tumors. We also analyzed the relationship between DLEC1 methylation and clinicopathological features in patients with renal cell carcinoma. We assessed DLEC1 inhibition of renal cell carcinoma cell growth by colony formation assay. RESULTS: DLEC1 methylation and down-regulation were detected in all renal cell carcinoma cell lines. Treatment with 5-aza-2'-deoxycytidine (Sigma) and/or trichostatin A (Cayman Chemical, Ann Arbor, Michigan) reversed methylation and restored DLEC1 expression, indicating that methylation directly mediates its silencing. Aberrant methylation was further detected in 25 of 81 primary tumors (31%) but only 1 of 53 nonmalignant renal tissues (2%) showed methylation. DLEC1 methylation status was significantly associated with TNM classification and grade in patients with renal cell carcinoma (chi-square test p = 0.01 and 0.04, respectively). DLEC1 ectopic expression in silenced renal cell carcinoma cells resulted in substantial tumor cell clonogenicity inhibition. CONCLUSIONS: To our knowledge we report for the first time that DLEC1 is often down-regulated by CpG methylation and shows tumor inhibitory function in renal cell carcinoma cells, indicating its role as a tumor suppressor. DLEC1 tumor specific methylation may serve as a biomarker for early detection and prognosis prediction of this tumor.

WNT5A exhibits tumor-suppressive activity through antagonizing the Wnt/beta-catenin signaling, and is frequently methylated in colorectal cancer.

PURPOSE: Aberrant activation of the Wnt/beta-catenin signaling pathway is associated with multiple tumors including colorectal cancer (CRC). WNT5A is a member of the nontransforming Wnt protein family, whose role in tumorigenesis is still ambiguous. We investigated its epigenetic alteration in CRCs. EXPERIMENTAL DESIGN: We examined its expression and methylation in normal colon, CRC cell lines, and tumors. We also evaluated its tumor-suppressive function and its modulation to Wnt signaling in CRC cells. RESULTS: WNT5A is silenced in most CRC cell lines due to promoter methylation, but is expressed in most normal tissues including the colon, and is unmethylated in normal colon epithelial cells. WNT5A expression could be reactivated by pharmacologic or genetic demethylation, indicating that methylation directly mediates its silencing. WNT5A methylation was frequently detected in CRC tumors (14 of 29, 48%), but only occasionally in paired normal colon tissues (2 of 15, 13%; P = 0.025). Ectopic expression of WNT5A, but not its nonfunctional short-isoform with the WNT domain deleted, in silenced CRC cells resulted in substantial inhibition of tumor cell clonogenicity, which is associated with down-regulated intracellular beta-catenin protein level and concomitant decrease in beta-catenin activity. CONCLUSIONS: WNT5A is frequently inactivated in CRC by tumor-specific methylation, and thus, is a potential biomarker. WNT5A could act as a tumor suppressor for CRC by antagonizing the Wnt/beta-catenin signaling.

Stopping anti-tumour necrosis factor therapy in patients with perianal Crohn's disease.

BACKGROUND: Little is known of the outcome of patients with perianal Crohn's disease after stopping anti-tumour necrosis factor (TNF) therapy. AIM: To evaluate the rate of relapse in perianal Crohn's disease (CD) after stopping anti-TNF therapy. METHODS: Consecutive perianal CD patients treated with anti-TNF therapy with subsequent discontinuation were retrieved from prospective inflammatory bowel disease database of institutes in Hong Kong, Shanghai, Taiwan, Malaysia, Thailand and Singapore from 1997 to June 2019. Cumulative probability of perianal CD relapse was estimated using Kaplan-Meier method. RESULTS: After a median follow-up of 89 months (interquartile range [IQR]: 65-173 months), 44 of the 78 perianal CD patients (56.4%) relapsed after stopping anti-TNF, defined as increased fistula drainage or recurrence of previously healed fistula, after stopping anti-TNF therapy. Cumulative probabilities of perianal CD relapse were 50.8%, 72.6% and 78.0% at 12, 36 and 60 months, respectively. Younger age at diagnosis of CD [adjusted hazard ratio (HR): 1.04; 95% CI 1.01-1.09; P = .04] was associated with a higher chance of perianal CD relapse. Among those with perianal CD relapse (n = 44), retreatment with anti-TNF induced remission in 24 of 29 patients (82.8%). Twelve (27.3%) patients required defunctioning surgery and one (2.3%) required proctectomy. Maintenance with thiopurine was not associated with a reduced likelihood of relapse [HR = 1.10; 95% CI: 0.58-2.12; P = .77]. Among the 17 patients who achieved radiological remission of perianal CD, five (35.3%) developed relapse after stopping anti-TNF therapy after a median of 6 months. CONCLUSIONS: More than half of the perianal CD patients developed relapse after stopping anti-TNF therapy. Most regained response after resuming anti-TNF. However, more than one-fourth of the perianal CD patients with relapse required defunctioning surgery. Radiological assessment before stopping anti-TNF is crucial in perianal CD.

Management and outcome of peptic ulcers or erosions in patients receiving a combination of aspirin plus clopidogrel.

BACKGROUND: This multicenter retrospective study investigated the management and outcome of patients with peptic ulcer/erosion-related aspirin and clopidogrel (A + C) cotherapy. METHODS: From January 2002 to September 2006, patients with endoscopically proven peptic ulcers/erosions after receiving A + C cotherapy were analyzed. RESULTS: This group consisted of 106 patients (age, 69.3 +/- 11.7 years). Ulcers/erosions developed in 27 patients during hospitalization for cardiac events and in 79 patients after hospital discharge. Of 27 patients hospitalized for acute cardiac events, gastrointestinal (GI) bleeding and dyspepsia occurred in 24 and three, respectively. The most common lesion was gastric ulcer. Of 79 discharged patients, GI bleeding and dyspepsia occurred in 64 and 15, respectively. The most common bleeding and dyspeptic lesions were gastric ulcer and gastritis, respectively. Overall, 17 patients underwent endoscopic hemostasis all successfully. A + C cotherapy was continued in 57 patients for a median (interquartile range) of 3.0 (6.2) months. Most were coprescribed a proton pump inhibitor (PPI) (53, 93%). No recurrent GI bleeding was observed. CONCLUSIONS: After A + C cotherapy, gastric ulcer or gastritis were the most common endoscopic lesions. The combination of a PPI and endoscopic treatment for ulcer bleeding was highly successful. After patient stabilization, continuation of A + C cotherapy with a PPI appears to be safe.

CMTM5 exhibits tumor suppressor activities and is frequently silenced by methylation in carcinoma cell lines.

PURPOSE: CMTM5 (CKLF-like MARVEL transmembrane domain containing member 5) is located at 14q11.2, a locus associated with multiple cancers. It has six RNA splicing variants with CMTM5-v1 as the major one. We explored its expression pattern in normal tissues and tumor cell lines, as well as its functions in carcinoma cells. EXPERIMENTAL DESIGN: We evaluated CMTM5 expression by semiquantitative reverse transcription-PCR (RT-PCR) in normal tissues and carcinoma cell lines of cervical, breast, nasopharyngeal, lung, hepatocellular, esophageal, gastric, colon, and prostate. We further examined CMTM5 promoter methylation in these cell lines. We also analyzed CMTM5 expression after 5-aza-2'-deoxycytidine treatment and genetic demethylation and the functional consequences of restoring CMTM5 in HeLa and PC-3 cells. RESULTS: CMTM5-v1 is broadly expressed in human normal adult and fetal tissues, but undetectable or down-regulated in most carcinoma cell lines. Its promoter methylation was detected in virtually all the silenced or down-regulated cell lines. The silencing of CMTM5 could be reversed by pharmacologic demethylation or genetic double-knockout of DNMT1 and DNMT3B, indicating methylation-mediated mechanism. Restoration of CMTM5-v1 suppressed carcinoma cell proliferation, migration, and invasion. CONCLUSIONS: These results indicate that CMTM5 exhibits tumor suppressor activities, but with frequent epigenetic inactivation in carcinoma cell lines.

Omeprazole promotes gastric epithelial cell migration.

Proton pump inhibitors (PPIs) are effective at preventing non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulcers. They are also superior to histamine H(2)-receptor antagonists and misoprostol in treating NSAID-induced gastric ulcer healing. This study explored whether omeprazole, a PPI, can modulate ulcer healing through epithelial cell proliferation and/or cell migration using a rat normal gastric epithelial cell line (RGM-1). Flow cytometry was used to determine cell proliferation and an artificial wound model was used to measure cell migration. Western blot analysis was performed to evaluate the possible mechanisms of action. Omeprazole treatment (10(-8), 10(-6) and 10(-4)M) for 12 and 24 h did not promote cell proliferation. However, similar doses of the drug (10(-6) and 10(-4)M) incubated for 24-48 h significantly promoted the basal cell migration of gastric epithelial cells. Further, the higher concentration of omeprazole (10(-4)M) reversed the inhibitory action of indometacin (10(-5)) on cell migration. Western blot results showed that omeprazole did not increase cyclooxygenase-2 expression and did not activate signal transduction pathways, including extracellular signal-regulated kinase (ERK1/ERK2), P38 mitogenic-activated protein kinase, and phosphatidyl inositol 3-kinase. The results suggest that omeprazole is beneficial in basal ulcer healing and it reversed the adverse action of indometacin on ulcer repair under acid-independent conditions. These actions are likely to be mediated through the promotion of gastric epithelial cell migration but not cell proliferation.

Aberrant methylation of the 8p22 tumor suppressor gene DLC1 in renal cell carcinoma.

Epigenetic mechanisms involving DNA methylation and chromatin remodeling are important in silencing tumor suppressor genes (TSG) in various malignancies, including renal cell carcinoma (RCC). DLC1 (deleted in liver cancer 1)/ARHGAP7 is a recently identified 8p22 candidate TSG. Frequent methylation of the DLC1 promoter with resultant gene silencing has been reported in several tumors, but not in RCC yet. We examined DLC1 promoter methylation in 34 primary RCCs and the corresponding non-malignant tissues, and the correlation of DLC1 methylation with the clinicopathological characteristics of RCC patients. Although DLC1 methylation and downregulation were only detected in one of seven RCC cell lines using methylation-specific PCR (MSP) and semi-quantitative reverse-transcription PCR, we found that the DLC1 promoter was methylated in 35% (12/34) of primary RCC tumors, which was further confirmed by direct sequencing of MSP products and high-resolution bisulfite genomic sequencing. In contrast, only one of the 34 (3%) non-malignant renal tissues had weak methylation. Aberrant DLC1 methylation appeared to be a relatively early event during renal tumorigenesis since 33% of the RCC tumors with pT1 (TNM staging) showed methylation, which is similar to other late stage tumors. Thus, our results demonstrated that DLC1 methylation occurs in a subset of RCC tumors and may play a role in renal carcinogenesis.

The current management of acute uncomplicated appendicitis: should there be a change in paradigm? A systematic review of the literatures and analysis of treatment performance.

INTRODUCTION: Appendectomy has long been the mainstay of intervention for acute appendicitis, aiming at preventing perforation, peritonitis, abscess formation and recurrence. With better understanding of the disease process, non-operative management (NOM) with antibiotics alone has been proved a feasible treatment for uncomplicated appendicitis. This article aimed at systematically reviewing the available literatures and discussing the question whether NOM should replace appendectomy as the standard first-line treatment for uncomplicated appendicitis. METHOD: A search of the Embase, Pubmed and Cochrane Library was performed using the keywords 'acute appendicitis' and 'antibiotic therapy'. Meta-analysis with inverse variance model for continuous variable and Mantel Haenzel Model for dichotomous variable was performed to evaluate the one year treatment efficacy, morbidities rate, sick leave duration and length of hospital stay associated with emergency appendectomy and NOM. RESULTS: Six randomized control trials were identified out of 1943 publications. NOM had a significant lower treatment efficacy rate at one year, 0.10 (95% CI 0.03-0.36, p < 0.01), when compared to appendectomy. The morbidities rate was comparable between the two interventions. The length of hospital stay was longer, with a mean difference of 1.08 days (95% CI 0.09-2.07, p = 0.03), and the sick leave duration was shorter, a mean difference of 3.37 days (95% CI -5.90 to -0.85 days, p < 0.01) for NOM. CONCLUSION: The paradigm remains unchanged, that appendectomy is the gold standard of treatment for uncomplicated appendicitis, given its higher efficacy rate when compared to NOM.

Frequent epigenetic silencing of the folate-metabolising gene cystathionine-beta-synthase in gastrointestinal cancer.

BACKGROUND: Both gastric and colorectal cancers (CRC) are the most frequently occurring malignancies worldwide with the overall survival of these patients remains unsatisfied. Identification of tumor suppressor genes (TSG) silenced by promoter CpG methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic biomarkers for early cancer detection and prognosis assessment. Cystathionine-beta-synthase (CBS) functions in the folate metabolism pathway, which is intricately linked to methylation of genomic DNA. Dysregulation of DNA methylation contributes substantially to cancer development. METHODOLOGY/PRINCIPAL FINDINGS: To identify potential TSGs silenced by aberrant promoter methylation in CRC, we analyzed tumor and adjacent tissues from CRC cases using the Illumina Human Methylation45 BeadChip. We identified hypermethylation of the CBS gene in CRC samples, compared to adjacent tissues. Methylation and decreased mRNA expression of CBS were detected in most CRC cell lines by methylation-specific PCR and semiquantitative RT-PCR, as well as in gastric cancer. Treatment with 5-aza-2'-deoxycytidine and/or trichostatin A reversed methylation and restored CBS mRNA expression indicating a direct effect. Aberrant methylation was further detected in 31% of primary CRCs (29 of 96) and 55% of gastric tumors (11 of 20). In contrast, methylation was seldom found in normal tissues adjacent to the tumor. CBS methylation was associated with KRAS mutations in primary CRCs (P = 0.04, by χ(2)-test). However, no association was found between CBS methylation or KRAS mutations with cancer relapse/metastasis in Stage II CRC patients. CONCLUSION: A novel finding from this study is that the folate metabolism enzyme CBS mRNA levels are frequently downregulated through CpG methylation of the CBS gene in gastric cancer and CRC, suggesting that CBS functions as a tumor suppressor gene. These findings warrant further study of CBS as an epigenetic biomarker for molecular diagnosis of gastrointestinal cancers.

A novel 19q13 nucleolar zinc finger protein suppresses tumor cell growth through inhibiting ribosome biogenesis and inducing apoptosis but is frequently silenced in multiple carcinomas.

Epigenetic disruption of tumor suppressor genes is frequently involved in tumorigenesis. We identified a novel 19q13 KRAB domain-containing zinc finger protein, ZNF545/ZFP82, broadly expressed in normal tissues but downregulated in multiple tumor cell lines. The ZNF545 promoter contains a CpG island, which is frequently methylated in cell lines. The transcriptional silencing of ZNF545 could be reversed by pharmacologic or genetic demethylation, indicating direct epigenetic silencing. ZNF545 was also frequently methylated in multiple primary tumors of nasopharyngeal, esophageal, lung, gastric, colon, and breast, but rarely in normal epithelial tissues and paired normal tissues. ZNF545 is located in the nucleus and mainly sequestered in nucleoli, functioning as a repressor. ZNF545 is able to repress NF-κB and AP-1 signaling pathways, whereas ectopic expression of ZNF545 in silenced tumor cells significantly inhibited their growth and induced apoptosis. Functional studies showed that ZNF545 was involved in ribosome biogenesis through inhibiting the activity of rDNA promoter and decreasing cellular protein translation efficiency. Thus, we identified ZNF545 as a novel tumor suppressor inducing tumor cell apoptosis, repressing ribosome biogenesis and target gene transcription. The tumor-specific methylation of ZNF545 could be an epigenetic biomarker for cancer diagnosis.

Dexamethasone inhibits tumor necrosis factor-alpha-stimulated gastric epithelial cell migration.

BACKGROUND: Cell migration (restitution) occurs in the early phase of gastric ulcer healing. Tumor necrosis factor (TNF)-alpha is overexpressed at the ulcer margin and plays a physiologic role in gastric ulcer healing. Dexamethasone, which is a potent corticosteroid, delays rat gastric ulcer healing. We evaluated whether dexamethasone inhibited TNF-alpha-stimulated gastric epithelial cell migration using a rat normal gastric epithelial cell line (RGM-1). METHODS: An artificial wound model was employed to measure cell migration. Western blot was performed to evaluate the possible mechanisms. Intracellular prostaglandin E2 level was measured using an enzyme-linked immunosorbent assay. RESULTS: TNF-alpha treatment (10 ng/mL) for 12-48 hours significantly increased RGM-1 cell migration, and TNF-alpha treatment increased cyclooxygenase (COX)-2 protein expression 8 hours later and prostaglandin E2 (PGE2) synthesis 12 hours later compared with control (p < 0.05). Dexamethasone (10(-6) M) significantly inhibited the stimulatory effect of TNF-alpha on RGM-1 cell migration, which was associated with a significant decrease in COX-2 expression and PGE2 level in cells (p < 0.05). CONCLUSION: TNF-alpha plays a regulatory role in rat gastric epithelial cell migration and dexamethasone inhibited TNF-alpha-stimulated cell migration, which was associated with a decrease in COX-2 expression and PGE2 formation.

CMTM3, located at the critical tumor suppressor locus 16q22.1, is silenced by CpG methylation in carcinomas and inhibits tumor cell growth through inducing apoptosis.

Closely located at the tumor suppressor locus 16q22.1, CKLF-like MARVEL transmembrane domain-containing member 3 and 4 (CMTM3 and CMTM4) encode two CMTM family proteins, which link chemokines and the transmembrane-4 superfamily. In contrast to the broad expression of both CMTM3 and CMTM4 in normal human adult tissues, only CMTM3 is silenced or down-regulated in common carcinoma (gastric, breast, nasopharyngeal, esophageal, and colon) cell lines and primary tumors. CMTM3 methylation was not detected in normal epithelial cell lines and tissues, with weak methylation present in only 5 of 35 (14%) gastric cancer adjacent normal tissues. Furthermore, immunohistochemistry showed that CMTM3 protein was absent in 12 of 35 (34%) gastric and 1 of 2 colorectal tumors, which was well correlated with its methylation status. The silencing of CMTM3 is due to aberrant promoter CpG methylation that could be reversed by pharmacologic demethylation. Ectopic expression of CMTM3 strongly suppressed the colony formation of carcinoma cell lines. In addition, CMTM3 inhibited tumor cell growth and induced apoptosis with caspase-3 activation. Thus, CMTM3 exerts tumor-suppressive functions in tumor cells, with frequent epigenetic inactivation by promoter CpG methylation in common carcinomas.

Dexamethasone inhibits basic fibroblast growth factor-stimulated gastric epithelial cell proliferation.

Basic fibroblast growth factor (bFGF) is essential for gastric ulcer healing, whereas glucocorticoids delay gastric ulcer healing. We found that dexamethasone inhibited bFGF-stimulated rat gastric epithelial RGM-1 cells proliferation and attempted to elucidate the possible mechanistic pathway. Flowcytometry was used to determine cell proliferation. Western blot and RT-PCR were performed to evaluate changes in signaling pathways. Results showed that bFGF significantly increased mRNA expression of FGF receptor (FGFR)1 and FGFR2 at 10 min and increased expression of phosphorylated extracellular signal-regulated kinase (pERK1/pERK2) but not phosphorylated p38 mitogen-activated protein kinase (MAPK) or phosphorylated phosphatidylinositol 3-kinase (PI3K) within 30 min. This was followed by an increase of cyclooxygenase (COX)-2 mRNA and protein expression at 30 and 240 min, respectively. Mitogen-activated protein kinase kinase (MEK) inhibitor-PD98059 (10(-5) M) markedly suppressed bFGF-stimulated COX-2 expression and cell proliferation, but neither p38 MAPK inhibitor-SB203580 nor PI3K inhibitor-Wortmannin had any effect. Dexamethasone (10(-6)M) substantially reduced bFGF-stimulated ERK activation at 10 min, COX-2 mRNA and protein expression at 30 and 240 min, respectively, and prostaglandin E(2) synthesis at 8 h. Dexamethasone (10(-6) M) also significantly decreased mRNA expression of FGFR1 and FGFR2 at basal and bFGF-stimulated conditions at 10 min. This study indicated that bFGF-stimulated gastric epithelial RGM-1 cells proliferation via up-regulating FGFR1 and FGFR2, activating ERK1/ERK2 signal transduction pathway and COX-2 pathway. Dexamethasone significantly suppresses bFGF-stimulated RGM-1 cells proliferation in part via down-regulation of FGFR1/FGFR2, then decreasing bFGF-stimulated activation of ERK1/ERK2, followed by inhibition of COX-2 activation, and finally DNA synthesis.

OPCML is a broad tumor suppressor for multiple carcinomas and lymphomas with frequently epigenetic inactivation.

BACKGROUND: Identification of tumor suppressor genes (TSGs) silenced by CpG methylation uncovers the molecular mechanism of tumorigenesis and potential tumor biomarkers. Loss of heterozygosity at 11q25 is common in multiple tumors including nasopharyngeal carcinoma (NPC). OPCML, located at 11q25, is one of the downregulated genes we identified through digital expression subtraction. METHODOLOGY/PRINCIPAL FINDINGS: Semi-quantitative RT-PCR showed frequent OPCML silencing in NPC and other common tumors, with no homozygous deletion detected by multiplex differential DNA-PCR. Instead, promoter methylation of OPCML was frequently detected in multiple carcinoma cell lines (nasopharyngeal, esophageal, lung, gastric, colon, liver, breast, cervix, prostate), lymphoma cell lines (non-Hodgkin and Hodgkin lymphoma, nasal NK/T-cell lymphoma) and primary tumors, but not in any non-tumor cell line and seldom weakly methylated in normal epithelial tissues. Pharmacological and genetic demethylation restored OPCML expression, indicating a direct epigenetic silencing. We further found that OPCML is stress-responsive, but this response is epigenetically impaired when its promoter becomes methylated. Ecotopic expression of OPCML led to significant inhibition of both anchorage-dependent and -independent growth of carcinoma cells with endogenous silencing. CONCLUSIONS/SIGNIFICANCE: Thus, through functional epigenetics, we identified OPCML as a broad tumor suppressor, which is frequently inactivated by methylation in multiple malignancies.