YAP inhibition overcomes adaptive resistance in HER2-positive gastric cancer treated with trastuzumab via the AKT/mTOR and ERK/mTOR axis.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) is a heterogeneous GC subtype characterized by the overexpression of HER2. To date, few specific targeted therapies have demonstrated durable efficacy in HER2-positive GC patients, with resistance to trastuzumab typically emerging within 1 year. However, the mechanisms of resistance to trastuzumab remain incompletely understood, presenting a significant challenge to clinical practice. METHODS: In this study, we integrated genetic screening and bulk transcriptome and epigenomic profiling to define the mechanisms mediating adaptive resistance to HER2 inhibitors and identify potential effective therapeutic strategies for treating HER2-positive GCs. RESULTS: We revealed a potential association between adaptive resistance to trastuzumab in HER2-positive GC and the expression of YES-associated protein (YAP). Notably, our investigation revealed that long-term administration of trastuzumab triggers extensive chromatin remodeling and initiates YAP gene transcription in HER2-positive cells characterized by the initial inhibition and subsequent reactivation. Furthermore, treatment of HER2-positive GC cells and cell line-derived xenografts (CDX) models with YAP inhibitors in combination with trastuzumab was found to induce synergistic effects through the AKT/mTOR and ERK/mTOR pathways. CONCLUSION: These findings underscore the pivotal role of reactivated YAP and mTOR signaling pathways in the development of adaptive resistance to trastuzumab and may serve as a promising joint target to overcome resistance to trastuzumab.

Predictors and outcomes of recurrent retroperitoneal liposarcoma: new insights into its recurrence patterns.

BACKGROUND: The clinical profiles of recurrent retroperitoneal liposarcoma (RLS) need to be explored. The recurrence patterns of RLS are controversial and ambiguous. METHODS: A total of 138 patients with recurrent RLS were finally recruited in the study. The analysis of overall survival (OS) and recurrence-free survival (RFS) was performed by Kaplan‒Meier analysis. To identify independent prognostic factors, all significant variables on univariate Cox regression analysis (P ≤ 0.05) were subjected to multivariate Cox regression analysis. The corresponding nomogram model was further built to predict the survival status of patients. RESULTS: Among patients, the 1-, 3-, and 5-year OS rates were 70.7%, 35.9% and 30.9%, respectively. The 1-, 3- and 5-year RFS rates of the 55 patients who underwent R0 resection were 76.1%, 50.8% and 34.4%, respectively. The multivariate analysis revealed that resection method, tumor size, status of pathological differentiation, pathological subtypes and recurrence pattern were independent risk factors for OS or RFS. Patients with distant recurrence (DR) pattern usually had multifocal tumors (90.5% vs. 74.7%, P < 0.05); they were prone to experience changes of pathological differentiation (69.9% vs. 33.3%, P < 0.05) and had a better prognosis than those with local recurrence (LR) pattern. R0 resection and combined organ resection favored the survival of patients with DR pattern in some cases. CONCLUSIONS: Patients with DR pattern had better prognosis, and they may benefit more from aggressive combined resection than those with LR pattern. Classifying the recurrence patterns of RLS provides guidance for individualized clinical management of recurrent RLS.

Methylome profiling identifies TCHH methylation in CfDNA as a noninvasive marker of liver metastasis in colorectal cancer.

Methylation of circulating free DNA (CfDNA) has emerged as an efficient marker of tumor screening and prognostics. However, no efficient methylation marker has been developed for monitoring liver metastasis (LM) in colorectal cancer (CRC). Utilizing methylome profiling and bisulfite sequencing polymerase chain reaction of paired primary and LM sites, significantly increased methylation of TCHH was identified in the process of LM in CRC in the present study. Methylight analysis of TCHH methylation in CfDNA displayed a promisingly discriminative power between CRC with and without LM. Besides, significant coefficient of TCHH methylation and LM tumor volume was also validated. Together, these results indicated the potential of TCHH methylation in CfDNA as a monitoring marker of LM in CRC.

Escherichia coli Nissle 1917 Protects Intestinal Barrier Function by Inhibiting NF-κB-Mediated Activation of the MLCK-P-MLC Signaling Pathway.

Escherichia coli Nissle 1917 (EcN), a kind of probiotic, has been reported to have a protective effect on the intestinal barrier function and can ameliorate certain gastrointestinal disorders. In this study, the potential protective effect of EcN on the intestinal barrier function in a septic mouse model induced by cecal ligation and puncture (CLP) operation was investigated. FITC-Dextran 4,000 Da (FD-4) flux and the expression levels of tight junction (TJ) proteins were measured to evaluate the protective effect of EcN on the intestinal barrier function. Then, Caco-2 monolayers were utilized to further investigate the protective effect of the EcN supernatant (EcNsup) on the barrier dysfunction induced by TNF-α and IFN-γ in vitro; the plasma level of both the cytokines increased significantly during sepsis. Transepithelial electrical resistance (TEER) and FD-4 transmembrane flux were measured, and the localization of ZO-1 and Occludin was investigated by immunofluorescence. The expression of MLCK and the phosphorylation of MLC were detected by western blot. The activation of NF-κB was explored by immunofluorescence, and CHIP assays were performed to investigate the conjunction of NF-κB with the promoter of MLCK. The results indicated that EcN protected the intestinal barrier function in sepsis by ameliorating the altered expression and localization of TJ proteins and inhibiting the NF-κB-mediated activation of the MLCK-P-MLC signaling pathway which might be one of the mechanisms underlying the effect of EcN.

1,25(OH)2D3 attenuates TGF-ß1/ß2-induced increased migration and invasion via inhibiting epithelial-mesenchymal transition in colon cancer cells.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been reported to inhibit proliferation and migration of multiple types of cancer cells. However, the mechanism underlying its anti-metastasis effect is not fully illustrated. In this study, the effect of 1,25(OH)2D3 on TGF-ß1/ß2-induced epithelial-mesenchymal transition (EMT) is tested in colon cancer cells. The results suggest that 1,25(OH)2D3 inhibited TGF-ß1/ß2-induced increased invasion and migration of in SW-480 and HT-29 cells. 1,25(OH)2D3 also inhibited the cadherin switch in SW-480 and HT-29 cells. TGF-ß1/ß2-induced increased expression of EMT-related transcription factors was also inhibited by 1,25(OH)2D3. 1,25(OH)2D3 also inhibited the secretion of MMP-2 and MMP-9 and increased expression of F-actin induced by TGF-ß1/ß2 in SW-480 cells. Taken together, this study suggests that the suppression of EMT might be one of the mechanisms underlying the anti-metastasis effect of 1,25(OH)2D3 in colon cancer cells.

Protective effect of hydrogen sulfide on TNF-α and IFN-γ-induced injury of intestinal epithelial barrier function in Caco-2 monolayers.

BACKGROUND AND AIM: Studies have verified the protective effect of Hydrogen Sulfide (H2S) on gastric ulcer and ulcerative colitis, but the mechanisms are not fully illustrated. In this study, the possible protective effect of H2S on TNF-α/IFN-γ induced barrier dysfunction was investigated in Caco-2 cell monolayers. METHOD: The barrier function of Caco-2 monolayers was evaluated by measuring trans-epithelial electrical resistance (TEER) and FITC-Dextran 4 kDa (FD-4) trans-membrane flux. ZO-1 and Occludin were chosen as markers of the localization of tight junction (TJ) proteins for immunofluorescence. The expression of MLCK and phosphorylation level of myosin light chain (MLC) were measured by immunoblotting. The activation of NF-kB p65 was analyzed by EMSA and immunofluorescence. RESULTS: NaHS at 500 uM significantly attenuated TNF-α/IFN-γ-indueced Caco-2 monolayer barrier injury. The increased expression of MLCK and increased phosphorylation level of MLC induced by TNF-α/IFN-γ was also inhibited significantly by NaHS. Additionally, NaHS inhibited TNF-α/IFN-γ induced activation and nuclear translocation of NF-kB p65. CONCLUSION: The present study reveals the protective effect of H2S on TNF-α and IFN-γ-induced injury of intestinal epithelial barrier function in Caco-2 monolayers and suggests that the suppression of MLCK-P-MLC signaling mediated by NF-kB P65 might be one of the mechanisms underlying the protective effect of H2S.

Predictive role of oxidative stress-related genes in colon cancer: a retrospective cohort study based on The Cancer Genome Atlas.

PURPOSE: This study aimed to elucidate the predictive role of an oxidative stress-related genes (OSRGs) model in colon cancer. MATERIALS AND METHODS: First, OSRGs that were differentially expressed between tumor and normal tissues were identified using The Cancer Genome Atlas (TCGA)-(Colorectal Adenocarcinoma) COAD dataset. Then, Lasso COX regression was performed to develop an optimal prognostic model patients were stratified into high- and low-risk groups based on the expression patterns of these genes. The model's validity was confirmed through Kaplan-Meier survival curves and receiver operating characteristic curve (ROC) analysis. Additionally, enrichment analyses were performed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) to uncover underlying mechanisms. RESULTS: A totally of 115 differentially expressed OSRGs were identified within the TCGA cohort, with 17 significantly linked to overall survival. These 17 genes were used to formulate a prognostic model that differentiated patients into distinct risk groups, with the high-risk group demonstrating a notably inferior overall survival rate. The risk score, when integrated with clinical and pathological data, emerged as an independent prognostic indicator of colon cancer. Further analyses revealed that the disparity in prognostic outcomes between risk groups could be attributed to the reactive oxygen species pathway and the p53 signaling pathway. CONCLUSION: A new prediction model was established based on OSRGs. CYP19A1, NOL3 and UCN were found to be highly expressed in tumor tissues and substantial clinical predictive significance. These findings offer new insights into the role of oxidative stress in colon cancer.

The BRD4 inhibitor JQ1 augments the antitumor efficacy of abemaciclib in preclinical models of gastric carcinoma.

BACKGROUND: Advanced gastric cancer (GC) is a lethal malignancy, harboring recurrent alterations in cell cycle pathway, especially the CDKN2A-CDK4/CDK6/CCND1 axis. However, monotherapy of CDK4/6 inhibitors has shown limited antitumor effects for GC, and combination treatments were urgently needed for CDK4/6 inhibitors. METHODS: Here, we performed a comprehensive analysis, including drug screening, pan-cancer genomic dependency analysis, and epigenetic sequencing to identify the candidate combination with CDK4/6 inhibitors. Mechanisms were investigated by bulk RNA-sequencing and experimental validation was conducted on diverse in vitro or in vivo preclinical GC models. RESULTS: We found that the BRD4 inhibitor JQ1 augments the antitumor efficacy of the CDK4/6 inhibitor abemaciclib (ABE). Diverse in vitro and in vivo preclinical GC models are examined and synergistic benefits from the combination therapy are obtained consistently. Mechanistically, the combination of ABE and JQ1 enhances the cell cycle arrest of GC cells and induces unique characteristics of cellular senescence through the induction of DNA damage, which is revealed by transcriptomic profiling and further validated by substantial in vitro and in vivo GC models. CONCLUSION: This study thus proposes a candidate combination therapy of ABE and JQ1 to improve the therapeutic efficacy and worth further investigation in clinical trials for GC.

The relationship between Ki-67 expression and imaging signs and pathological features in GISTs.

Introduction: To investigate the correlations between the Ki-67 index and plain-scan computerized tomography (CT) signs and pathological features of gastrointestinal stromal tumor (GIST) tissue. Materials and methods: Data from 186 patients with GIST diagnosed by pathology and immunohistochemistry (IHC) in Peking University First Hospital from May 2016 to May 2022 were analyzed. The patients were divided into two groups: Ki-67 ≤5% and >5%. Correlation analysis, univariate and multivariate Logistic regression analysis were used to explore the correlations between CT signs, pathological features, and Ki-67 expression. Results: Univariate indicators correlated with the Ki-67 index were mitotic count, pathological grade, tumor hemorrhage, tumor necrosis, tumor size, and tumor density. Multivariate Logistic regression indicated that the mitotic count [odds ratio (OR) 10.222, 95% confidence interval (CI) 4.312-31.039], pathological grade (OR 2.139, 95% CI 1.397-3.350), and tumor size (OR 1.096, 95% CI 1.020-1.190) were independently associated with the Ki-67 expression level. The concordance indexes (C-index) for the pathological features and CT signs models were 0.876 (95% CI 0.822-0.929) and 0.697 (95% CI 0.620-0.774), respectively, with positive predictive values of 93.62% and 58.11% and negative predictive values of 81.29% and 75.89%, respectively. After internal verification by the Bootstrap method, the fitting degree of the pathological features model was found to be better than that of the CT signs model. Conclusion: Mitotic count, pathological risk grading, and tumor size are independent risk factors correlating with high Ki-67 index. These results indicate that the Ki-67 index reflects tumor malignancy and can predict recurrence and metastasis of GIST.

Treatment with S-adenosylmethionine ameliorates irinotecan-induced intestinal barrier dysfunction and intestinal microbial disorder in mice.

This study aimed to investigate the protective effects of S-adenosylmethionine (SAM) on irinotecan-induced intestinal barrier dysfunction and microbial ecological dysregulation in both mice and human colon cell line Caco-2, which is widely used for studying intestinal epithelial barrier function. Specifically, this study utilized Caco-2 monolayers incubated with 7-ethyl-10-hydroxycamptothecin (SN-38) as well as an irinotecan-induced diarrhea model in mice. Our study found that SAM pretreatment significantly reduced body weight loss and diarrhea induced by irinotecan in mice. Furthermore, SAM inhibited the increase of intestinal permeability in irinotecan-treated mice and ameliorated the decrease of Zonula occludens-1(ZO-1), Occludin, and Claudin-1 expression. Additionally, irinotecan treatment increased the relative abundance of Proteobacteria compared to the control group, an effect that was reversed by SAM administration. In Caco-2 monolayers, SAM reduced the expression of reactive oxygen species (ROS) and ameliorated the decrease in transepithelial electrical resistance (TER) and increase in fluorescein isothiocyanate-dextran 4000 Da (FD-4) flux caused by SN-38. Moreover, SAM attenuated changes in the localization and distribution of ZO-1and Occludin in Caco-2 monolayers induced by SN-38 and protected barrier function by inhibiting activation of the p38 MAPK/p65 NF-κB/MLCK/MLC signaling pathway. These findings provide preliminary evidence for the potential use of SAM in treating diarrhea caused by irinotecan.

Neutrophils as key regulators of tumor immunity that restrict immune checkpoint blockade in liver cancer.

OBJECTIVE: Liver cancer is a deadly malignancy associated with high mortality and morbidity. Less than 20% of patients with advanced liver cancer respond to a single anti-PD-1 treatment. The high heterogeneity of neutrophils in the tumor immune microenvironment in liver cancer may contribute to resistance to immune checkpoint blockade (ICB). However, the underlying mechanism remains largely unknown. METHODS: We established an orthotopic liver cancer model by using transposable elements to integrate the oncogenes Myc and KrasG12D into the genome in liver cells from conditional Trp53 null/null mice (pTMK/Trp53-/-). Flow cytometry and immunohistochemistry were used to assess the changes in immune cells in the tumor microenvironment. An ex vivo coculture assay was performed to test the inhibitory effects of tumor-associated neutrophils (TANs) on CD8+ T cells. The roles of neutrophils, T cells, and NK cells were validated through antibody-mediated depletion. The efficacy of the combination of neutrophil depletion and ICB was evaluated. RESULTS: Orthotropic pTMK/Trp53-/- mouse liver tumors displayed a moderate response to anti-Ly6G treatment but not PD-1 blockade. Depletion of neutrophils increased the infiltration of CD8+ T cells and decreased the number of exhausted T cells in the tumor microenvironment. Furthermore, depletion of either CD8+ T or NK cells abrogated the antitumor efficacy of anti-Ly6G treatment. Moreover, the combination of anti-Ly6G with anti-PD-L1 enhanced the infiltration of cytotoxic CD8+ T cells and thereafter resulted in a significantly greater decrease in tumor burden. CONCLUSIONS: Our data suggest that TANs may contribute to the resistance of liver cancer to ICB, and combining TAN depletion with T cell immunotherapy synergistically increases antitumor efficacy.

CBS-H2S axis preserves the intestinal barrier function by inhibiting COX-2 through sulfhydrating human antigen R in colitis.

INTRODUCTION: Lipopolysaccharide (LPS) causes lesions of the epithelial barrier, which allows translocation of pathogens from the intestinal lumen to the host's circulation. Hydrogen sulfide (H2S) regulates multiple physiological and pathological processes in colonic epithelial tissue, and CBS-H2S axis involved in multiple gastrointestinal disorder. However, the mechanism underlying the effect of the CBS-H2S axis on the intestinal and systemic inflammation in colitis remains to be illustrated. OBJECTIVES: To investigate the effect of CBS-H2S axis on the intestinal and systematic inflammation related injuries in LPS induced colitis and the underlying mechanisms. METHODS: Wild type and CBS-/+ mice were used to evaluate the effect of endogenous and exogenous H2S on LPS-induced colitis in vivo. Cytokine quantitative antibody array, western blot and real-time PCR were applied to detect the key cytokines in the mechanism of action. Biotin switch of S-sulfhydration, CRISPR/Cas9 mediated knockout, immunofluorescence and ActD chase assay were used in the in vitro experiment to further clarify the molecular mechanisms. RESULTS: H2S significantly alleviated the symptoms of LPS-induced colitis in vivo and attenuated the increase of COX-2 expression. The sulfhydrated HuR increased when CBS express normally or GYY4137 was administered. While after knocking kown CBS, the expression of COX-2 in mice colon increased significantly, and the sulfhydration level of HuR decreased. The results in vitro illustrated that HuR can increase the stability of COX-2 mRNA, and the decrease of COX-2 were due to increased sulfhydration of HuR rather than the reduction of total HuR levels. CONCLUSION: These results indicated that CBS-H2S axis played an important role in protecting intestinal barrier function in colitis. CBS-H2S axis increases the sulfhydration level of HuR, by which reduces the binding of HuR with COX-2 mRNA and inhibited the expression of COX-2.

The Alleviating Effects and Mechanisms of Betaine on Dextran Sulfate Sodium-Induced Colitis in Mice.

SCOPE: Ulcerative colitis (UC) is an intestinal disease that is becoming increasingly prevalent and is often overlooked in early stages, and its pathogenesis is often closely related to inflammatory processes. Betaine is a natural product with anti-inflammatory effects that exists in a wide range of plants and animals. METHODS AND RESULTS: In this study, the protective effects of betaine are investigated on intestinal barrier function in a mouse model, a dextran sulfate sodium-induced ulcerative colitis and its mechanism of action in the inflammatory context. FITC-dextran 4000 Da (FD-4) flux, disease activity index, histopathological scores, and inflammatory factor levels in sera are determined across different groups. In addition, Caco-2 cell monolayer barrier function is evaluated by transepithelial resistance and FD-4 flux. The expression levels and distribution of tight junction proteins are determined using Western blot and immunofluorescence, respectively. Activation of the NF-κBp65/MLCK/p-MLC signaling pathway is detected by Western blot. Chromatin immunoprecipitation is performed to examine the binding of NF-κB to the MLCK gene promoter. The results indicated that betaine inhibits NF-κB-mediated activation of the MLCK/p-MLC signaling pathway to protect the intestinal barrier function of mice with UC. CONCLUSION: Betaine can be used as a potential candidate drug to improve intestinal barrier dysfunction in patients with UC.

Rare squamous cell carcinoma of the jejunum causing perforated peritonitis: A case report.

BACKGROUND: Adenocarcinoma has the highest incidence among malignant tumors of the small intestine (SI). Squamous cell carcinoma (SCC) often occurs in organs covered with squamous epithelium. Primary or metastatic SCC originating from the SI is very rare, with very few cases reported in the literature. CASE SUMMARY: This case report involves a 69-year-old man who developed abdominal pain after lunch. After admission, an abdominal computed tomography scan revealed perforation of the alimentary canal and multiple abnormal low-density lesions in the liver. During laparotomy, an approximately 4 cm × 3 cm-sized solid tumor was found in the jejunum, located 30 cm from the Treitz ligament, with a perforation. An intestinal segment of approximately 15 cm was removed, including the perforated portion. The pathological result was SCC. In combination with liver imaging, a diagnosis of SI SCC with multiple liver metastases was considered. The patient died from hepatic failure 1 mo after the operation. CONCLUSION: SI tumors are very rare compared to those originating in other digestive organs. Due to its insidious onset, the diagnosis of this disease is usually delayed. Clinicians must pay close attention to digestive symptoms such as persistent abdominal pain and melena.