Overexpression of VSNL1 Enhances Cell Proliferation in Colorectal Carcinogenesis.

INTRODUCTION: We have previously reported that overexpression of visinin-like protein 1 (VSNL1) is frequently observed in advanced colorectal adenocarcinomas and correlates with poorer prognosis. In this study, we determined the levels of VSNL1 expression in the earlier stages of colorectal tumors including adenomas and adenocarcinomas, and attempted to clarify the functional significance of VSNL1 overexpression in colorectal carcinogenesis. METHODS: Levels of VSNL expression in colorectal tumor tissues were analyzed using immunohistochemistry. The effects of VSNL1 downregulation and overexpression on cell proliferation, resistance to apoptosis, and invasiveness were determined using two VSNL1-overexpressing colorectal cancer cell lines, CW-2 and HCT-116 and VSNL1 inducibly expressing SNU-C5, respectively. Gene expression signatures in VSNL1-downregulated CW-2 and HCT-116 were identified using transcriptome and gene set enrichment analyses. RESULTS: VSNL1 expression was restricted to only a few crypt cells in the non-tumorous epithelium, whereas it became enhanced in adenomas and adenocarcinomas with the progression of tumorigenesis. Downregulation of VSNL1 in CW-2 and HCT-116 cells suppressed their proliferation through induction of apoptosis. Conversely, overexpression of VSNL1 in SNU-C5 cells enhanced resistance to anoikis. Transcriptome and gene set enrichment analyses revealed that downregulation of VSNL1 altered the expression level of the apoptosis-related gene set in CW-2 and HCT-116 cells. CONCLUSION: VSNL1 plays a role in both the development and progression of colorectal tumors by enhancing cell viability.

Efficient Establishment of Bile-Derived Organoids From Biliary Cancer Patients.

Patient-derived tumor organoids have considerable potential as an in vitro diagnostic tool for drug susceptibility testing. In the present study, we investigated whether bile collected for diagnostic purposes could be a potential source for the establishment of biliary cancer organoids. Among 68 cases of biliary cancer, we successfully generated 60 bile-derived organoids (BDOs) from individual patients. Consistent with previous reports that described biliary cancer organoids from surgical tissues, the BDOs showed diverse morphologies such as simple cysts, multiloculated cysts, thick capsulated cysts, and solid masses. They also harbored mutations in KRAS and TP53 at frequencies of 15% and 55%, respectively. To enrich the cancer organoids by removing contaminated noncancerous components of BDOs, we attempted to verify the effectiveness of 3 different procedures, including repeat passage, xenografting, and selection with an MDM2 inhibitor for TP53 mutation-harboring BDOs. By monitoring the sequence and expression of mutated TP53, we found that all these procedures successfully enriched the cancer organoids. Our data suggest that BDOs can be established with minimal invasiveness from almost all patients with biliary cancers, including inoperable cases. Thus, despite some limitations with respect to the characterization of BDOs and methods for the enrichment of cancer cell-derived organoids, our data suggest that BDOs could have potential applications in personalized medicine.

Association of immune-related expression profile with sensitivity to chemotherapy in esophageal squamous cell carcinoma.

Neoadjuvant chemotherapy (NAC) followed by surgery is one of the standard therapeutic approaches in Japan for patients with locally advanced esophageal carcinoma. Recently, the JCOG1109 study revealed that NAC with docetaxel, cisplatin and 5-fluorouracil (5-FU) (DCF-NAC) is superior to NAC with cisplatin and 5-FU, and has now become the standard preoperative chemotherapy. Using a microarray system, we have previously investigated the expression profiles of endoscopic biopsy samples from patients with esophageal squamous cell carcinoma (ESCC) before DCF-NAC (preNAC) and identified 17 molecules as biomarkers predictive of a pathologically complete response to DCF-NAC. Here, we re-grouped our previous dataset based on the histopathological response grade with the addition of several microarray profiles and conducted a re-analysis using bioinformatic web tools including DAVID, GSEA, UALCAN, and CIBERSORTx. We identified 204 genes that were differentially expressed between the highly resistant and sensitive groups. Some of these differentially expressed genes (DEGs) were related to the immune response and showed higher expression in the sensitive group. UALCAN showed that high expression of 28 of the top 50 DEGs was associated with a favorable prognosis (p < 0.25), and that this reached a significant (p < 0.05) level for 18 of them, suggesting that patients with high expression of these genes might have benefited from chemotherapy and thus had a better outcome. In preNAC biopsy tissues from a DCF-sensitive case, we demonstrated the presence of cells expressing mRNA for CXCL9, one of the prognosis-related DEGs. Our results highlight the association of immune-related expression profile in preNAC ESCC with the DCF-NAC efficacy.

Involvement of clusterin expression in the refractory response of pancreatic cancer cells to a MEK inhibitor.

Constitutive activation of the mitogen-activated protein kinase (MAPK) signaling pathway is essential for tumorigenesis of pancreatic ductal adenocarcinoma (PDAC). To date, however, almost all clinical trials of inhibitor targeting this pathway have failed to improve the outcome of patients with PDAC. We found that implanted MIA Paca2, a human PDAC cell line sensitive to a MAPK inhibitor, PD0325901, became refractory within a week after treatment. By comparing the expression profiles of MIA Paca2 before and after acquisition of the refractoriness to PD0325901, we identified clusterin (CLU) as a candidate gene involved. CLU was shown to be induced immediately after treatment with PD0325901 or expressed primarily in more than half of PDAC cell lines, enhancing cell viability by escaping from apoptosis. A combination of PD0325901 and CLU downregulation was found to synergistically or additively reduce the proliferation of PDAC cells. In surgically resected PDAC tissues, overexpression of CLU in cancer cells was observed immunohistochemically in approximately half of the cases studied. Collectively, our findings highlight the mechanisms responsible for the rapid refractory response to MEK inhibitor in PDAC cells, suggesting a novel therapeutic strategy that could be applicable to patients with PDAC using inhibitor targeting the MAPK signaling pathway and CLU.

Glucose metabolic upregulation via phosphorylation of S6 ribosomal protein affects tumor progression in distal cholangiocarcinoma.

BACKGROUND: The prognosis of distal cholangiocarcinoma (dCCA) remains poor; thus, the identification of new therapeutic targets is warranted. Phosphorylated S6 ribosomal protein indicates a mammalian target of rapamycin complex 1 (mTORC1) activity, and mTORC1 plays a central role in controlling cell growth and regulating glucose metabolism. We aimed to clarify the effect of S6 phosphorylation on tumor progression and the glucose metabolic pathway in dCCA. METHODS: Thirty-nine patients with dCCA who underwent curative resection were enrolled in this study. S6 phosphorylation and the expression of GLUT1 were evaluated by immunohistochemistry, and their relationship with clinical factors was investigated. The effect of S6 phosphorylation on glucose metabolism with PF-04691502 treatment, an inhibitor of S6 phosphorylation, was examined in cancer cell lines by Western blotting and metabolomics analysis. Cell proliferation assays were performed with PF-04691502. RESULTS: S6 phosphorylation and the expression of GLUT1 were significantly higher in patients with an advanced pathological stage. Significant correlations between GLUT1 expression, S6 phosphorylation, and SUV-max of FDG-PET were shown. In addition, cell lines with high S6 phosphorylation levels showed high GLUT1 levels, and the inhibition of S6 phosphorylation reduced the expression of GLUT1 on Western blotting. Metabolic analysis revealed that inhibition of S6 phosphorylation suppressed pathways of glycolysis and the TCA cycle in cell lines, and then, cell proliferation was effectively reduced by PF-04691502. CONCLUSION: Upregulation of glucose metabolism via phosphorylation of S6 ribosomal protein appeared to play a role in tumor progression in dCCA. mTORC1 may be a therapeutic target for dCCA.

Use of a novel endoscopic overtube with bilateral tool channels for endoscopic resection of experimental lesions and repair of intestinal defects in the right colon: preclinical trial.

BACKGROUND: Endoscopic tumor resection and intestinal defect repair are technically challenging leading to invasive surgery and colectomy performed for resection of benign polyps. In this study, we evaluated the use of an endoscopic overtube with bilateral tool channels for these procedures. METHODS: Using a fresh porcine colorectum in a 3D ex vivo model, 3 cm lesions at the posterior wall of the transverse colon were removed by two different techniques: standard endoscopic submucosal dissection (ESD) technique (STD, n = 12) and ESD using the overtube with an endoscopic snare and grasper through the bilateral channels (OT, n = 12). Procedure times and the number of muscular injuries were evaluated. Using the same model, 5-10 mm full-thickness perforations within a 3 cm mucosal defect at the posterior wall of the transverse colon were closed by two different techniques: standard endoscopic closure technique (STD, n = 12) and endoscopic closure using the overtube with two graspers (OT, n = 12). The outcomes measured included bursting pressure and the number of endoscopic clips used for closure. RESULTS: Endoscopic resection of lesions was performed by the OT group in a significantly shorter total procedure time (STD vs. OT = median 38.9 min vs. 17.3, p < 0.001) and with fewer muscular injuries (median 0 vs. 2, p = 0.002), compared with the STD group. After repair of intestinal defects, the OT group showed higher median bursting pressures (STD vs. OT = 11.2 mmHg vs. 57.1, p = 0.008) despite using fewer clips (median 13 vs. 10, p < 0.001). CONCLUSION: This study demonstrates a novel traction technique with an endoscopic overtube using multiple instruments to remove lesions and repair intestinal defects in the colon more effectively. This endoscopic platform could provide a safe alternative to invasive surgical treatment.

Enhanced phosphorylation of c-Jun by cisplatin treatment as a potential predictive biomarker for cisplatin response in combination with patient-derived tumor organoids.

Despite recent advances in sequencing technology and large-scale drug screenings employing hundreds of cell lines, the predictive accuracy of mutation-based biomarkers is still insufficient as a guide for cancer therapy. Therefore, novel types of diagnostic methods using alternative biomarkers would be highly desirable. We have hypothesized that sensitivity-specific changes in the phosphorylation of signaling molecules could be useful in this respect. Here, with the aim of developing a method for predicting the response of cancers to cisplatin using a combination of specific biomarker(s) and patient-derived tumor organoids (PDOs), we found that cisplatin-sensitive cell lines or PDOs showed enhanced phosphorylation of c-Jun (p-c-Jun) within 24 h after cisplatin treatment. We also compared the responses of 6 PDOs to cisplatin with the therapeutic effect of neoadjuvant chemotherapy (docetaxel/cisplatin/5-fluorouracil) in 6 matched patients. Mechanistically, the c-Jun induction was partly related to TNF signaling induced by cisplatin. Our data suggest that enhanced phosphorylation of c-Jun in response to cisplatin treatment could be a predictive biomarker for the efficacy of cisplatin in selected cancer patients.

Potential association of eEF1A dimethylation at lysine 55 in the basal area of Helicobacter pylori-eradicated gastric mucosa with the risk of gastric cancer: a retrospective observational study.

BACKGROUND: Although eradication therapy for chronic Helicobacter pylori (H. pylori) reduces the risk of gastric cancer (GC), its effectiveness is not complete. Therefore, it is also critically important to identifying those patients who remain at high risk after H. pylori eradication therapy. Accumulation of protein methylation is strongly implicated in cancer, and recent study showed that dimethylation of eEF1A lysine 55 (eEF1AK55me2) promotes carcinogenesis in vivo. We aimed to investigate the relationship between eEF1A dimethylation and H. pylori status, efficacy of eradication therapy, and GC risk in H. pylori-eradicated mucosa, and to reveal the potential downstream molecules of eEF1A dimethylation. METHODS: Records of 115 patients (11 H. pylori-negative, 29 H. pylori-positive, 75 post-eradication patients) who underwent upper gastrointestinal endoscopy were retrospectively reviewed. The eEF1A dimethyl level was evaluated in each functional cell type of gastric mucosa by immunofluorescent staining. We also investigated the relationship between eEF1AK55me2 downregulation by CRISPR/Cas9 mediated deletion of Mettl13, which is known as a dimethyltransferase of eEF1AK55me2. RESULTS: The level of eEF1A dimethylation significantly increased in the surface and basal areas of H. pylori-positive mucosa compared with the negative mucosa (surface, p = 0.0031; basal, p = 0.0036, respectively). The eEF1A dimethyl-levels in the surface area were significantly reduced by eradication therapy (p = 0.005), but those in the basal area were maintained even after eradication therapy. Multivariate analysis revealed that high dimethylation of eEF1A in the basal area of the mucosa was the independent factor related to GC incidence (odds ratio = 3.6611, 95% confidence interval = 1.0350-12.949, p = 0.0441). We also showed the relationship between eEF1A dimethylation and expressions of reprogramming factors, Oct4 and Nanog, by immunohistochemistry and in vitro genome editing experiments. CONCLUSIONS: The results indicated that H. pylori infection induced eEF1A dimethylation in gastric mucosa. The accumulation of dimethyl-eEF1A in the basal area of the mucosa might contribute to GC risk via regulation of reprograming factors in H. pylori eradicated-gastric mucosa.

Analysis of long-term serological and histological changes after eradication of Helicobacter pylori.

Stratification of gastric cancer risk by measuring serological biomarkers is useful for screening of gastric cancer. However, this method has problem such as overlooking past infected patients. We aimed to evaluate the association between Helicobacter pylori infection status and serological biomarkers. We divided 5,268 patients according to Helicobacter pylori infection status and past infected patients were divided into 12 groups according to time elapsed since eradication. We analyzed mean serum H. pylori immunoglobulin G antibody, pepsinogen titers, histological and endoscopic atrophy score of each group. Mean H. pylori immunoglobulin G antibody showed a decreasing tendency, there was no significant difference from the uninfected group at 11 years after eradication (p = 0.19). PGI, PGII decreased in short term after eradication. However, both PGI and PGII gradually increased as long-term changes after eradication, became comparable to those in the uninfected group (p = 0.41, p = 0.37, respectively). Histological atrophy improved gradually, became equivalent to uninfected group. Endoscopic atrophy score did not improve for long term after eradication. In conclusion, patients with long term after eradication reach the uninfected condition serologically, histologically. Endoscopic assessment of gastric mucosal atrophy may be useful for accurate assessment of gastric cancer risk.

Early response in phosphorylation of ribosomal protein S6 is associated with sensitivity to trametinib in colorectal cancer cells.

Mutations in RAS or BRAF are associated with poor prognosis and resistance to epidermal growth factor receptor (EGFR)-targeted therapy in colorectal cancer (CRC). Despite their common ability to activate downstream genes such as MEK and ERK, the therapeutic benefit of MEK inhibitors for patients with RAS/BRAF mutant CRC is limited, highlighting the need for biomarkers to predict the efficacy of MEK inhibition. Previously, we reported that a change in phosphorylation of ribosomal protein S6 (pS6) after MEK inhibition was significantly associated with sensitivity to MEK inhibition in gastric cancer cells. Here, we investigated the value of the response in pS6 for predicting the efficacy of trametinib, a MEK inhibitor, in patients with RAS/BRAF mutant CRC using patient-derived CRC organoids. We found that a subset of CRC cell lines and organoids were sensitive to trametinib. The change in phosphorylated ERK, a downstream molecule of the RAS/RAF/MEK pathway, was not significantly associated with trametinib sensitivity. On the other hand, only those with sensitivity showed a reduction of pS6 levels in response to trametinib. The change in pS6 after trametinib treatment was detectable by Western blotting, immunohistochemistry or immunocytochemistry. We also demonstrated an impact of MEK inhibition on pS6 in vivo using a xenograft model. Our data suggest that, in combination with patient-derived organoids, immunostaining-based detection of pS6 could be useful for prediction of trametinib sensitivity.

Gastric mucosal changes, and sex differences therein, after Helicobacter pylori eradication: A long-term prospective follow-up study.

BACKGROUND AND AIM: Improvement of atrophic gastritis and intestinal metaplasia (IM) is considered to reduce the gastric cancer risk, but whether it can be achieved by H. pylori eradication (HPE) remains controversial. To evaluate the effect of HPE, we observed the gastric mucosa for up to17 years after HPE and sex differences in gastric mucosa. METHODS: In total, 172 patients (94 males, 78 females) with HPE were enrolled. Annual histological evaluations were performed for up to 17 years. The grades of mononuclear cells, neutrophils, atrophy, IM in the antrum and corpus were evaluated using the updated Sydney system. RESULTS: Relative to the pre-HPE period, atrophy had improved significantly 1 year after HPE in the antrum (1.50 ± 0.75 vs. 1.21 ± 1.25, P < 0.01) and corpus (0.59 ± 0.75 vs. 0.18 ± 0.52, P < 0.05). IM showed no significant change during 17 years after HPE at either biopsy site. Atrophy scores did not differ significantly between males and females. IM scores were significantly higher in males than in females before eradication (antrum, 0.67 ± 0.94 vs. 0.44 ± 0.77, P = 0.003, corpus, 0.20 ± 0.62 vs. 0.047 ± 0.21, P = 0.0027) and at most observation timepoints. CONCLUSIONS: During 17 years after HPE, atrophy, but not IM, improved significantly at the greater curvatures of the antrum and corpus. IM was significantly more severe in males than in females. Careful follow-up after HPE based on sex differences in gastric mucosal characteristics is important.

Immunohistochemical differences in gastric mucosal damage between nodular and non-nodular gastritis caused by Helicobacter pylori infection.

In this study, the level of cell damage were analyzed immuno-histochemically to clarify the association between nodular gastritis and undifferentiated gastric cancer. Thirty patients of nodular gastritis were enrolled as the nodular gastritis group. Thirty patients of non-nodular gastritis were enrolled as the control group. They were evaluated according to the updated Sydney system and used for immunohistochemical staining (p53, Ki-67, E-cadherin, and 8-OHdG). The scores based on the updated Sydney system were significantly higher in the nodular group than in the non-nodular group for histologically assessed inflammation and activity in the gastric corpus (1.91 ±â€„0.77 vs 1.58 ±â€„0.60, p = 0.049, 0.83 ±â€„0.81 vs 0.44 ±â€„0.64, p = 0.032). On immunostaining, the detection of E-cadherin was lower in the nodular group for both the antrum (1.0 ±â€„0.62 vs 1.47 ±â€„0.85, p = 0.047) and the corpus (1.16 ±â€„0.81 vs 1.48 ±â€„0.71, p = 0.043) and the p53 labeling index of the gastric corpus was higher in the nodular group than in the non-nodular group (3.06 ±â€„1.94 vs 2.03 ±â€„1.99, p = 0.015). Nodular gastritis showed significant severe inflammation and immunohistochemical cell damage compared with non-nodular gastritis. These findings may play an important role in the oncogenesis of undifferentiated gastric cancer in nodular gastritis.

Helicobacter pylori infection modulates endogenous hydrogen sulfide production in gastric cancer AGS cells.

BACKGROUND: Persistent Helicobacter pylori infection induces gastric mucosal atrophy, which is a precancerous condition. Hydrogen sulfide (H2 S), a gaseous biological transmitter, has been implicated in both the physiological functions of the gastrointestinal tract and its diseases. To understand gastric epithelial cell response against H pylori infection, we investigated the metabolic changes of gastric cancer cells co-cultured with H pylori and observed the modulation of endogenous H2 S production. MATERIALS AND METHODS: Gastric cancer AGS cells were co-cultured with an H pylori standard strain possessing bacterial virulence factor CagA (ATCC 43504) and a strain without CagA (ATCC 51932). Three hours after inoculation, the cells were subjected to metabolomics analysis using gas chromatography-tandem mass spectrometry (GC-MS/MS). Orthogonal projections to latent structures discriminant analysis (OPLS-DA) and pathway analysis were performed. In addition, intracellular H2 S levels were measured by using HSip-1 fluorescent probe. RESULTS: Results of OPLS-DA showed a significant difference between the metabolism of untreated control cells and cells inoculated with the H pylori strains ATCC 51932 or ATCC 43504, mainly due to 45 metabolites. Pathway analysis with the selected metabolites indicated that methionine metabolism, which is related to H2 S production, was the most frequently altered pathway. H pylori-inoculated cells produced more endogenous H2 S than control cells. Moreover, ATCC 43504-inoculated cells produced less H2 S than ATCC 51932-inoculated cells. CONCLUSIONS: H pylori infection modulates endogenous H2 S production in AGS cells, suggesting that H2 S might be one of the bioactive molecules involved in the biological mechanisms of gastric mucosal disease including mucosal atrophy.

Influence of acotiamide on 13C-urea breath test for Helicobacter pylori diagnosis.

The Helicobacter pylori infection and functional dyspepsia are often coexisted. The effect of acotiamide, a drug for functional dyspepsia, on the result of Helicobacter pylori diagnosis has yet to be studied. We evaluated the influence of acotiamide on the results of Helicobacter pylori diagnosis in the 13C-urea breath test. Twenty patients with Helicobacter pylori-positive functional dyspepsia were treated with 100 mg of acotiamide three times a day for two weeks. Changes in 13C-urea breath test were investigated before and after administration, and two weeks after administration as the follow-up period. The 13C-urea breath test and the medical questionnaire of modified frequency scale for the symptoms of gastroesophageal reflux disease were conducted at every period. Nineteen patients were included for analysis. No patients showed negative in 13C-urea breath test at Weeks 2 and 4. On the symptom scale, dyspepsia and total scores decreased from Week 0 to Week 2 and increased from Week 2 to Week 4, and the improvement rates of the dyspepsia score at Week 2 was 63%. In conclusion, we confirmed that acotiamide is unlikely to influence the result of 13C-urea breath test and it may improve the symptoms of functional dyspepsia during Helicobacter pylori eradication treatment.

Evaluation of a Novel Anti-H. pylori Antibody Detection Kit by Latex Turbidimetric Immunoassay.

BACKGROUND: While all modalities used for diagnosis of Helicobacter pylori (H. pylori) have demonstrated sufficient sensitivity and specificity, each test has advantages and limitations. The serum test for anti-H. pylori antibody with the latex method is noninvasive, easy, and inexpensive; it is thus a useful tool for mass-screening for H. pylori. In this study, we evaluated the utility of a newly developed latex kit, in comparison with other serum diagnostic kits based on enzyme-linked immunosorbent assay (ELISA). METHODS: In total, 187 subjects (77: H. pylori-positive, 75: H. pylori-negative, 35: previous infection with H. pylori) seen at Oita University Hospital during the period from January 1988 to September 2014 were enrolled in the study. All subjects were evaluated with 4 types of serum H. pylori antibody kits. One modality was based on the use of latex (Denka Kit, Denka Seiken Co., Ltd., Tokyo, Japan). Three kits were based on the use of ELISA. The E-Plate II Eiken (Eiken Chemical Co., Ltd., Tokyo, Japan) is henceforth referred to as Kit A. The Premier H. pylori kit (Meridian Bioscience, Inc., USA) is referred to as Kit B. The Platelia H. pylori IgG (Bio-Rad, Marnes-la-Coquette, France) is referred to as Kit C. RESULTS: Evaluation of 152 study participants, including some who were positive for H. pylori and some who were negative, sensitivity, specificity, and accuracy values were as follows: for the Denka kit, these values were, respec-tively, 92.2%, 93.3%, and 92.8%. For Kit A, these values were 88.3%, 100.0%, and 194.1%. For Kit B, these values were 98.7%, 76.0%, and 87.5%. For Kit C, these values were 98.7%, 80.0%, and 89.5%. The specificity of Kit A was > 90%. Sensitivity was > 90% for Kits B and C. For the Denka kit, both sensitivity and specificity were > 90%. Among the 35 subjects previously infected with H. pylori, the rate of positive diagnosis was 48.6% (17/35) with the Denka kit, 17.1% (6/35) with Kit A, 54.3% (19/35) with Kit B, and 54.3% (19/35) with Kit C. The rate of positive diagnosis was significantly higher with the Denka kit than with Kit A (p < 0.05). CONCLUSIONS: An assay based on use of the latex method, H. pylori-latex Seiken, demonstrated satisfactory sensitivity and specificity for detecting serum levels of H. pylori antibody. The performance of this kit was equivalent to that of ELISA kits currently used for the same purpose. This kit is therefore considered to be extremely suitable for diagnosis of H. pylori and mass-screening of patients at high risk for gastric cancer.

Differences in Helicobacter pylori and CagA antibody changes after eradication between subjects developing and not developing gastric cancer.

We evaluated serological Helicobacter pylori and cytotoxin-associated gene A (CagA) antibodies and endoscopic atrophy after eradication to identify factors predicting post-eradication gastric cancer development. Thirty-five patients with successful eradiation were divided into the post-eradication gastric cancer (13 cases) and non-gastric cancer (22 cases) groups. Serum Helicobacter pylori and CagA antibody titers and endoscopic atrophy before and six years after eradication were examined. Median Helicobacter pylori antibody titers had decreased significantly from baseline at 0.5-2 years after eradication in both groups (gastric cancer group, from 39.0 to 11.0 U/ml, p = 0.011; non-gastric cancer group, from 29.6 to 4.97 U/ml, p<0.001), but were significantly higher in the gastric cancer than in the non-gastric cancer group (p = 0.029). Median serum CagA antibody titers had also decreased significantly at 0.5-2 years after eradication (gastric cancer group, from 6.35 to 3.23 U/ml, p = 0.028; non-gastric cancer group, from 9.88 to 1.21 U/ml, p = 0.0045). Serum CagA in each group showed no significance. Endoscopic atrophy improved significantly after eradication in the non-gastric cancer, but not the gastric cancer, group (p = 0.0007). In conclusion, changes in Helicobacter pylori and CagA antibody titers and endoscopic atrophy after eradication might be useful as predictive factors for post-eradication gastric cancer.

Endoscopic gastric mucosal atrophy as a predictor of colorectal polyps: a large scale case-control study.

Although some studies have indicated a correlation between Helicobacter pylori infection and the risk of colorectal neoplasms, these findings have not been consistent and are controversial. This case-control study aimed to investigate the association between endoscopic gastric mucosal atrophy and colorectal polyp occurrence. Records of 7,394 participants who underwent colonoscopy examinations from August 2008 to July 2018 were reviewed retrospectively. A total of 2,404 subjects were registered; 1,565 (65.1%) were in the gastric mucosal atrophy-positive group and 1,138 (47.3%) had colorectal polyps. The multivariate analysis adjusted by age, sex, smoking habits, alcohol habits, hemoglobin A1c, and systolic blood pressure indicated that patients in the gastric mucosal atrophy-positive group more frequently had colorectal polyps compared with patients in the gastric mucosal atrophy-negative group (odds ratio, 3.27; 95% confidence interval, 2.68-4.01; p<0.001). An analysis of the association between gastric mucosal atrophy degree and colorectal polyp status indicated that, compared with mild gastric mucosal atrophy, severe gastric mucosal atrophy was associated with a higher risk of proximal colon polyps (odds ratio, 1.47; 95% confidence interval, 1.05-2.07; p = 0.024) and two or more colorectal polyps (odds ratio, 1.80; 95% confidence interval, 1.30-2.49; p<0.001). In conclusion, gastric mucosal atrophy found during esophagogastroduodenoscopy may be an indication for complete colon screening.

Endoscopic and Immunohistochemical Characteristics of Gastric Cancer with versus without Helicobacter Pylori Eradication.

BACKGROUND/AIMS: The rate of gastric cancer (GC) after Helicobacter pylori eradication has gradually increased; therefore, we investigate the clinicopathological features of GC following eradication in comparison with those of GC with H. pylori infection. METHODS: This study included 50 subjects with GC after eradication (GCE) and 151 patients with GC with H. pylori infection (GCI). Clinicopathological factors were assessed. The manifestation of GC was further evaluated using immunohistochemical analysis and in situ hybridization. RESULTS: Macroscopic analysis revealed a significantly higher ratio of depressed type /elevated type in the GCE compared with the GCI (30/19 vs. 61/77, p = 0.041). The gastric phenotype was more common in the GCE compared with the GCI, and the proportion of CDX2-positive cases was lower in the GCE (8 out of 18; 44.4%) compared with the GCI (18 out of 19; 94.7%; p = 0.00082). Ki-67 labeling index was significantly lower in the GCE (32.03 ± 22.15) compared with the GCI (79.20 ± 14.87, p < 0.0001). No patient in the GCE showed evidence of Epstein-Barr virus infection. CONCLUSION: The clinicopathological characteristics of GC following H. pylori eradication differ from those of GC in patients with H. pylori infection in terms of morphology, mucin phenotype, and proliferation rate.

Reduced phosphorylation of ribosomal protein S6 is associated with sensitivity to MEK inhibition in gastric cancer cells.

Gastric cancer (GC) is characterized by amplifications of receptor tyrosine kinases (RTK) and KRAS, therefore, targeting of the RTK/KRAS downstream pathways could help to broaden the applicability of molecular targeted therapy for GC. We assembled a panel of 48 GC cell lines and screened predictors of responsiveness to inhibition of the RAF/MEK/ERK pathway, one of the RTK/KRAS downstream pathways. We found that GC cells with MET amplification or KRAS mutation, but not amplification, tended to be sensitive to MEK inhibition. However, several cell lines without RTK/KRAS alterations also showed high sensitivity to MEK inhibition. We then focused on the phosphorylation of RTK/KRAS downstream molecules to screen for predictors' sensitivity to MEK inhibition. We found that the phosphorylation level of mammalian target of rapamycin complex 1 (mTORC1) downstream molecules, including p70S6K, 4EBP1, and S6, was significantly associated with sensitivity to MEK inhibition in GC cells (P < 0.05), suggesting that mTORC1 activity is related to the sensitivity to MEK inhibition. Furthermore, the change in mTORC1 activity after MEK inhibition was also significantly associated with this sensitivity (P < 0.001). Among the mTORC1 downstream molecules, the change in S6 phosphorylation (pS6) showed the most significant correlation with sensitivity. Using xenograft models derived from highly sensitive and resistant cell lines, we found specific reduction of pS6 in xenografts from highly sensitive cell lines after 6 h of treatment with an MEK inhibitor. Thus, our data suggest the potential clinical applicability of an MEK inhibitor for a proportion of GC patients who could be selected on the basis of pS6 change after MEK inhibition.