PTCH1 mutation as a potential predictive biomarker for immune checkpoint inhibitors in gastrointestinal cancer.

Immune checkpoint inhibitors (ICIs) have become prominent therapies for gastrointestinal cancer (GC). However, it is urgent to screen patients who can benefit from ICIs. Protein patched homolog 1 (PTCH1) is a frequently altered gene in GC. We attempt to explore the association between PTCH1 mutation and immunotherapy efficacy. The Memorial Sloan Kettering Cancer Center (MSKCC) cohort (n = 236) with GC (esophageal, gastric and colorectal cancers) patients receiving ICIs was used for discovery and the Peking University Cancer Hospital (PUCH) GC cohort (n = 92) was used for validation. Overall survival (OS) and tumor mutational burden (TMB) of the PTCH1 mutant-type (PTCH1-MUT) and PTCH1 wild-type (PTCH1-WT) groups were compared. Furthermore, GC data were collected from The Cancer Genome Atlas to assess the potential mechanisms. In the MSKCC cohort, PTCH1-MUT group showed significantly better OS (P = 0.017) and higher TMB. Multivariate analysis showed that PTCH1 mutation was associated with better OS. In the PUCH cohort, PTCH1-MUT group showed significantly longer OS (P = 0.036) and progression-free survival, and higher durable clinical benefit and TMB. Immune cell infiltration analysis revealed that PTCH1-MUT group had significantly higher distributions of CD8 T cells, CD4 T cells, NK cells, mast cells and M1 cells. The PTCH1-MUT group showed significantly higher expression of most immune-related genes. Gene set enrichment analysis showed that the PTCH1-MUT group had enriched INF-γ response, INF-α response, glycolysis and reactive oxygen species pathway gene sets. PTCH1 mutation may represent a potential biomarker for predicting ICIs response in GC. Nevertheless, prospective cohort studies should be performed to further validate our results.

Dissecting the heterogeneities of the tumor microenvironment between metastatic and nonmetastatic primary colorectal cancer patients by single-cell RNA sequencing.

AIMS: One of the main factors hampering the long-term prognosis of colorectal cancer (CRC) patients is distant metastasis. However, the driving factors of CRC metastasis have not been clarified at the single-cell level, which limits the in-depth study of accurate prediction and prevention of CRC metastasis to improve the prognosis. MATERIALS AND METHODS: Heterogeneities in the tumor microenvironment (TME) between metastatic and nonmetastatic CRC were investigated by single-cell RNA (scRNA) sequencing data. In detail, 50,462 single cells from 20 primary CRC samples, including 40,910 cells from nonmetastatic CRC (M0 group) and 9552 cells from metastatic CRC (M1 group), were systematically analyzed in this study. KEY FINDINGS: Based on the single-cell atlas, we revealed that cancer cells and fibroblasts accounted for relatively high proportions in metastatic CRC compared with nonmetastatic CRC. Moreover, two specific cancer cell subtypes (FGGY+SLC6A6+ and IGFBP3+KLK7+ cancer cells) and three specific fibroblast subtypes (ADAMTS6+CAPG+, PIM1+SGK1+ and CA9+UPP1+ fibroblasts) in metastatic CRC were identified. The functional and differentiation characteristics of these specific cell subclusters were elucidated by enrichment and trajectory analyses. SIGNIFICANCE: These results provide fundamental knowledge for future in-depth research to screen effective methods and drugs to predict and prevent CRC metastasis to improve prognosis.

Identification of the molecular characteristics associated with microsatellite status of colorectal cancer patients for the clinical application of immunotherapy.

Background: Mismatch repair-proficient (pMMR) microsatellite stability (MSS) in colorectal cancer (CRC) indicates an unfavorable therapeutic response to immunotherapy with immune checkpoint inhibitors (ICIs). However, the molecular characteristics of CRC patients with pMMR MSS remain largely unknown. Methods: Heterogeneities between mismatch repair-deficient (dMMR) microsatellite instability (MSI) and pMMR MSS CRC patients were investigated at the single-cell level. Next, an MSS-related risk score was constructed by single-sample gene set enrichment analysis (ssGSEA). The differences in immune and functional characteristics between the high- and low-score groups were systematically analyzed. Results: Based on the single-cell RNA (scRNA) atlas, an MSS-specific cancer cell subpopulation was identified. By taking the intersection of the significant differentially expressed genes (DEGs) between different cancer cell subtypes of the single-cell training and validation cohorts, 29 MSS-specific cancer cell marker genes were screened out for the construction of the MSS-related risk score. This risk score signature could efficiently separate pMMR MSS CRC patients into two subtypes with significantly different immune characteristics. The interactions among the different cell types were stronger in the MSS group than in the MSI group, especially for the outgoing signals of the cancer cells. In addition, functional differences between the high- and low-score groups were preliminarily investigated. Conclusion: In this study, we constructed an effective risk model to classify pMMR MSS CRC patients into two completely different groups based on the specific genes identified by single-cell analysis to identify potential CRC patients sensitive to immunotherapy and screen effective synergistic targets.

3D matrix promotes cell dedifferentiation into colorectal cancer stem cells via integrin/cytoskeleton/glycolysis signaling.

The potential for tumor occurrence triggered by cancer stem cells (CSCs) has emerged as a significant challenge for human colorectal cancer therapy. However, the underlying mechanism of CSC development remains controversial. Our study provided evidence that the bulk of tumor cells could dedifferentiate to CSCs and reacquire CSC-like phenotypes if cultured in the presence of extracellular matrix reagents, such as Matrigel and fibrin gels. In these 3D gels, CD133- colorectal cancer cells can regain tumorigenic potential and stem-like phenotypes. Mechanistically, the 3D extracellular matrix could mediate cytoskeletal F-actin bundling through biomechanical force associated receptors integrin ß1 (ITGB1), contributing to the release of E3 ligase tripartite motif protein 11 (TRIM11) from cytoskeleton and degradation of the glycolytic rate-limiting enzyme phosphofructokinase (PFK). Consequently, PFK inhibition resulted in enhanced glycolysis and upregulation of hypoxia-inducible factor 1 (HIF1α), thereby promoting the reprogramming of stem cell transcription factors and facilitating tumor progression in patients. This study provided novel insights into the role of the extracellular matrix in the regulation of CSC dedifferentiation in a cytoskeleton/glycolysis-dependent manner.

A case of echinococcosis in Hunan Province. / æ¹–å—çœåŒ è™«ç— 1例.

Echinococcosis is mainly prevalent in the agricultural and pastoral areas in the northwest of China, but it is relatively rare in Hunan Province. Here, we reported the clinical data of a case of echinococcosis in Hunan Province. The patient was an 11-year-old male, who sought treatment at the Second Xiangya Hospital of Central South University due to abdominal mass. According to the symptoms, signs, and laboratory examinations, he was initially diagnosed as "intra-abdominal mass" and "spleen cyst". Subsequently, he underwent abdominal massive occupying resection and splenectomy. Postoperative pathological examination revealed the cuticle and germinal layer of hydatid and protoscolex, which was consistent with characteristics of echinococcosis. In addition, the serological examination showed that the specific anti-hydatid IgG antibody was positive. Combined with the patient's condition, he was given praziquantel treatment. After a month of follow-up, the patient was asymptomatic.

LncRNA NR2F2-AS1 functions as a tumor suppressor in gastric cancer through targeting miR-320b/PDCD4 pathway.

Gastric cancer is among the most frequently occurring gastrointestinal malignancies with a high mortality rate worldwide. Long non-coding RNAs (lncRNAs) are defined as core regulators in the occurrence and progression of multiple cancers, including gastric carcinoma. Mounting evidence has indicated that NR2F2-AS1 can inhibit several malignant tumors. However, the function and potential mechanism of NR2F2-AS1 remain unclear. In the current study, we found that NR2F2-AS1 was weakly expressed in gastric cancer cells in comparison with normal cells. The study has further disclosed that ectopic of NR2F2-AS1 repressed cell proliferation, migration, invasion and EMT whereas it promoted cell apoptosis in gastric carcinoma. Subsequently, our results confirmed that miR-320b was negatively regulated and that suppression of miR-320b alleviated the malignant behaviors of GC cells. More importantly, PDCD4 was a target of miR-320b. Mechanistically, NR2F2-AS1 modulated the expression level of PDCD4 by sponging miR-320b. Finally, rescue assays demonstrated that NR2F2-AS1 down-regulated PDCD4 expression to restrain the development of gastric cancer by competitively binding to miR-320b. On the whole, our study revealed the role of NR2F2-AS1/miR-320b/PDCD4 regulatory network in gastric cancer, suggesting NR2F2-AS1 may represent a novel therapeutic target for patients with gastric carcinoma.

Promotion of gastric tumor initiating cells in a 3D collagen gel culture model via YBX1/SPP1/NF-κB signaling.

BACKGROUND: The high potential for tumor recurrence and chemoresistance is a major challenge of clinical gastric cancer treatment. Increasing evidence suggests that the presence of tumor initiating cells (TICs) is the principal cause of tumor recurrence and chemoresistance. However, the underlying mechanism of TIC development remains controversial. METHODS: To identify novel molecular pathways in gastric cancer, we screened the genomic expression profile of 155 gastric cancer patients from the TCGA database. We then described an improved 3D collagen I gels and tested the effects of collagen on the TIC phenotype of gastric cells using colony formation assay, transwell assay, and nude mouse models. Additionally, cell apoptosis assay was performed to examine the cytotoxicity of 5-fluorine and paclitaxel on gastric cancer cells cultured in 3D collagen I gels. RESULTS: Elevated expression of type I collagen was observed in tumor tissues from high stage patients (stage T3-T4) when compared to the low stage group (n=10, stage T1-T2). Furthermore, tumor cells seeded in a low concentration of collagen gels acquired TIC-like phenotypes and revealed enhanced resistance to chemotherapeutic agents, which was dependent on an integrin ß1 (ITGB1)/Y-box Binding Protein 1 (YBX1)/Secreted Phosphoprotein 1 (SPP1)/NF-κB signaling pathway. Importantly, inhibition of ITGB1/NF-κB signaling efficiently reversed the chemoresistance induced by collagen and promoted anticancer effects in vivo. CONCLUSIONS: Our findings demonstrated that type I collagen promoted TIC-like phenotypes and chemoresistance through ITGB1/YBX1/SPP1/NF-κB pathway, which may provide novel insights into gastric cancer therapy.

miR­195 promotes LPS­mediated intestinal epithelial cell apoptosis via targeting SIRT1/eIF2a.

A microarray analysis of an animal model with experimental sepsis induced by caecal ligation and puncture revealed that the level of microRNA­195 (miR­195) was upregulated. However, to the best of our knowledge, the role of miR­195 in sepsis remains unknown. The present study investigated the effect of miR­195 on apoptosis in sepsis and investigated the underlying mechanism. The level of miR­195 was measured in human intestinal epithelial cells following exposure to lipopolysaccharide (LPS). Cell viability and apoptosis were detected using Cell Counting kit­8 and flow cytometry assays. The expression levels of apoptosis­associated proteins were determined using western blot analysis. In addition, a dual­luciferase reporter assay was employed to verify the association between miR­195 and sirtuin 1 (SIRT1). Furthermore, the SIRT1 inhibitor EX527 was applied to further confirm the regulatory network of miR­195/SIRT1 in LPS­induced apoptosis. It was demonstrated that LPS significantly inhibited cell viability and promoted cell apoptosis in NCM460 cells in a dose­dependent manner. In addition, miR­195 was significantly upregulated following LPS treatment. The present results revealed that silencing miR­195 prevented apoptosis and alleviated cell injury in LPS­induced NCM460 cells. Further investigation demonstrated that miR­195 bound directly to and negatively regulated SIRT1. Inhibition of SIRT1 reversed the protective effects of miR­195­silencing on the apoptosis and viability of NCM460 cells. Furthermore, silencing miR­195 prevented endoplasmic reticulum (ER) stress­induced apoptosis via a downregulation of SIRT1 and its downstream effectors, including activating transcription factor 4, C/EBP homologous protein, glucose­regulated protein 78 and growth arrest and DNA­damage protein 34, as well as the phosphorylation of eukaryotic translation initiation factor 2A. In conclusion, the present study revealed a novel mechanism by which miR­195 regulates SIRT1­mediated downstream effectors in ER stress­induced apoptosis in sepsis.

MiR-29c inhibits cell growth, invasion, and migration of pancreatic cancer by targeting ITGB1.

MiR-29c is frequently dysregulated in many cancers; however, the roles of miR-29c in pancreatic cancer (PC) and underlying mechanisms remain poorly understood. In this study, we investigated the role of miR-29c in PC. Using quantitative real-time polymerase chain reaction, we demonstrated that miR-29c was frequently downregulated in clinical PC tissues and cell lines. Overexpression of miR-29c significantly inhibited the proliferation, migration, and invasion of PC cells in vitro, which demonstrated that miR-29c acts as a tumor suppressor in PC cells. Further analysis revealed that ITGB1 is one of the functional target genes of miR-29c, and knockdown of ITGB1 inhibited the proliferation, migration, and invasion of PC cells, which was similar to the effects of overexpression of miR-29c. Taken together, our results highlight the significance of miR-29c-ITGB1 interaction in the development and progression of PC.