RAB13 as a novel prognosis marker promotes proliferation and chemotherapeutic resistance in gastric cancer

Spatially Resolved Tumor Ecosystems and Cell States in Gastric Adenocarcinoma Progression and Evolution

SIGNIFICANCE

Integration of spatial transcriptomic (GeoMx Digital Spatial Profiler) and single-cell RNA sequencing data from multiple gastric cancers identifies spatially resolved expression-based intratumoral heterogeneity, associated with distinct immune microenvironments. We uncovered two separate evolutionary trajectories associated with specific molecular subtypes, clinical prognoses, stromal neighborhoods, and genetic drivers. Tumor-stroma interfaces emerged as a unique state of tumor ecology.

Screening of prognostic core genes based on cell-cell interaction in the peripheral blood of patients with sepsis

Peripheral blood samples from 15 septic patients admitted within 24 h and 8 healthy volunteers were used to conduct RNA-seq. Quantitative PCR of THP1 cells was performed to investigate the expression levels of the selected key genes. A total of 1,128 differential genes were identified, 721 of which were upregulated and 407 were downregulated. These genes are mainly involved in neutrophil activation, T cell regulation, immune effector process regulation, cytokine receptor activity, and cytokine binding. The six target genes were ELANE, IL1R2, RAB13, RNASE3, FCGR1A, and TLR5. In the sepsis group, FCGR1A and TLR5 were positively associated with survival compared to ELANE, IL1R2, RAB13, and RNASE3, which were adversely associated with survival. Furthermore, a meta-analysis based on public databases revealed an increased expression of these six target genes in the peripheral blood of patients with sepsis. In addition, we discovered that monocytes primarily express these genes. Using qPCR, we confirmed that these six important genes were highly expressed in lipopolysaccharide-treated THP1 cells. In summary, these findings suggest that ELANE, IL1R2, RAB13, RNASE3, FCGR1A, and TLR5 may influence the prognosis of patients with sepsis and provide novel insights and potential avenues for the treatment of sepsis.

Identification and validation of Rab GTPases RAB13 as biomarkers for peritoneal metastasis and immune cell infiltration in colorectal cancer patients

Background

As one of the most common cancer, colorectal cancer (CRC) is with high morbidity and mortality. Peritoneal metastasis (PM) is a fatal state of CRC, and few patients may benefit from traditional therapies. There is a complex interaction between PM and immune cell infiltration. Therefore, we aimed to determine biomarkers associated with colorectal cancer peritoneal metastasis (CRCPM) and their relationship with immune cell infiltration.

Methods

By informatic analysis, differently expressed genes (DEGs) were selected and hub genes were screened out. RAB13, one of the hub genes, was identificated from public databases and validated in CRC tissues. The ESTIMATE, CEBERSORT and TIMER algorithms were applied to analyze the correlation between RAB13 and immune infiltration in CRC. RAB13's expression in different cells were analyzed at the single-cell level in scRNA-Seq. The Gene Set Enrichment Analysis (GSEA) was performed for RAB13 enrichment and further confirmed. Using oncoPredict algorithm, RAB13's impact on drug sensitivity was evaluated.

Results

High RAB13 expression was identified in public databases and led to a poor prognosis. RAB13 was found to be positively correlated with the macrophages and other immune cells infiltration and from scRNA-Seq, RAB13 was found to be located in CRC cells and macrophages. GSEA revealed that high RAB13 expression enriched in a various of biological signaling, and oncoPredict algorithm showed that RAB13 expression was correlated with paclitaxel sensitivity.

Conclusion

Our study indicated clinical role of RAB13 in CRC-PM, suggesting its potential as a therapeutic target in the future.

The Role of Rab GTPases in the development of genetic and malignant diseases

Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.

Clinical implications of RAB13 expression in pan-cancer based on multi-databases integrative analysis

Worldwide, cancer is a huge burden, and each year sees an increase in its incidence. RAB (Ras-related in brain) 13 is crucial for a number of tumor types. But more research on RAB13's tumor-related mechanism is still required. This study's goal was to investigate RAB13's function in human pan-cancer, and we have also preliminarily explored the relevant mechanisms. To investigate the differential expression, survival prognosis, immunological checkpoints, and pathological stage of RAB13 in human pan-cancer, respectively, databases of TIMER2.0, GEPIA 2, and UALCAN were employed. CBioPortal database was used to analyze the mutation level, meanwhile, PPI network was constructed based on STRING website. The putative functions of RAB13 in immunological infiltration were investigated using single sample gene set enrichment analysis (ssGSEA). The mechanism of RAB13 in hepatocellular cancer was also briefly investigated by us using gene set enrichment analysis (GSEA). RAB13 was differentially expressed in a number of different cancers, including liver hepatocellular carcinoma (LIHC), stomach adenocarcinoma (STAD), etc. Additionally, RAB13 overexpression in LGG and LIHC is associated with a worse prognosis, including overall survival (OS) and disease-free survival (DFS). Then, we observed that early in BLCA, BRAC, CHOL, ESCA, HNSC, KICH, KIRC, LIHC, LUAD, LUSC, and STAD, the level of RAB13 expression was raised. Next, we found that "amplification" was the most common mutation in RAB13. The expression of SLC39A1, JTB, SSR2, SNAPIN, and RHOC was strongly positively linked with RAB13, according to a correlation study. RAB13 favorably regulated B cell, CD8 + T cell, CD4 + T cell, macrophage, neutrophil, and dendritic cell in LIHC, according to immune infiltration analysis. Immune checkpoint study revealed a positive correlation between RAB13 expression and PD1, PDL1, and CTLA4 in LIHC. According to GSEA, RAB13 is involved in a number of processes in LIHC, including MTORC1 signaling, MYC targets v1, G2M checkpoint, MITOTIC spindle, DNA repair, P53 pathway, glycolysis, PI3K-AKT-MTOR signaling, etc. RAB13 is a possible therapeutic target in LIHC and can be used as a prognostic marker.

Single-cell sequencing analysis reveals development and differentiation trajectory of Schwann cells manipulated by M. leprae

BACKGROUND

M. leprae preferentially infects Schwann cells (SCs) in the peripheral nerves leading to nerve damage and irreversible disability. Knowledge of how M. leprae infects and interacts with host SCs is essential for understanding mechanisms of nerve damage and revealing potential new therapeutic strategies.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a time-course single-cell sequencing analysis of SCs infected with M. leprae at different time points, further analyzed the heterogeneity of SCs, subpopulations associated with M. leprae infection, developmental trajectory of SCs and validated by Western blot or flow cytometry. Different subpopulations of SCs exhibiting distinct genetic features and functional enrichments were present. We observed two subpopulations associated with M. leprae infection, a stem cell-like cell subpopulation increased significantly at 24 h but declined by 72 h after M. leprae infection, and an adipocyte-like cell subpopulation, emerged at 72 h post-infection. The results were validated and confirmed that a stem cell-like cell subpopulation was in the early stage of differentiation and could differentiate into an adipocyte-like cell subpopulation.

CONCLUSIONS/SIGNIFICANCE

Our results present a systematic time-course analysis of SC heterogeneity after infection by M. leprae at single-cell resolution, provide valuable information to understand the critical biological processes underlying reprogramming and lipid metabolism during M. leprae infection of SCs, and increase understanding of the disease-causing mechanisms at play in leprosy patients as well as revealing potential new therapeutic strategies.

Mechanism of Tumor-Platelet Communications in Cancer

BACKGROUND

Thrombosis is one of the main complications in cancer patients often leading to mortality. However, the mechanisms underlying platelet hyperactivation are poorly understood.

METHODS

Murine and human platelets were isolated and treated with small extracellular vesicles (sEVs) from various cancer cell lines. The effects of these cancer-sEVs on platelets were evaluated both in vitro and in vivo using various approaches, including the detection of cancer-sEV-specific markers in murine platelets and patient samples, measurement of platelet activation and thrombosis assays. Signaling events induced by cancer-sEVs and leading to platelet activation were identified, and the use of blocking antibodies to prevent thrombosis was demonstrated.

RESULTS

We demonstrate that platelets very effectively take up sEVs from aggressive cancer cells. The process of uptake is fast, proceeds effectively in circulation in mice, and is mediated by the abundant sEV membrane protein-CD63. The uptake of cancer-sEVs leads to the accumulation of cancer cell-specific RNA in platelets in vitro and in vivo. The human prostate cancer-sEV-specific RNA marker PCA3 is detected in platelets of ~70% of prostate cancer patients. This was markedly reduced after prostatectomy. In vitro studies showed that platelet uptake of cancer-sEVs induces strong platelet activation in a CD63-RPTPα (receptor-like protein tyrosine phosphatase alpha)-dependent manner. In contrast to physiological agonists ADP and thrombin, cancer-sEVs activate platelets via a noncanonical mechanism. Intravital studies demonstrated accelerated thrombosis both in murine tumor models and in mice that received intravenous injections of cancer-sEVs. The prothrombotic effects of cancer-sEVs were rescued by blocking CD63.

CONCLUSIONS

Tumors communicate with platelets by means of sEVs, which deliver cancer markers and activate platelets in a CD63-dependent manner leading to thrombosis. This emphasizes the diagnostic and prognostic value of platelet-associated cancer markers and identifies new pathways for intervention.

RAB27A promotes the proliferation and invasion of colorectal cancer cells

Colorectal cancer (CRC) is one of the most commonly diagnosed cancer types worldwide. Despite significant advances in prevention and diagnosis, CRC is still one of the leading causes of cancer-related mortality globally. RAB27A, the member of RAB27 family of small GTPases, is the critical protein for intracellular secretion and has been reported to promote tumor progression. However, it is controversial for the role of RAB27A in CRC progression, so we explored the exact function of RAB27A in CRC development in this study. Based on the stable colon cancer cell lines of RAB27A knockdown and ectopic expression, we found that RAB27A knockdown inhibited proliferation and clone formation of SW480 colon cancer cells, whereas ectopic expression of RAB27A in RKO colon cancer cells facilitated cell proliferation and clone formation, indicating that RAB27A is critical for colon cancer cell growth. In addition, our data demonstrated that the migration and invasion of colon cancer cells were suppressed by RAB27A knockdown, but promoted by RAB27A ectopic expression. Therefore, RAB27A is identified as an onco-protein in mediating CRC development, which may be a valuable prognostic indicator and potential therapeutic target for CRC.

Mevalonate pathway orchestrates insulin signaling via RAB14 geranylgeranylation-mediated phosphorylation of AKT to regulate hepatic glucose metabolism

Statin use accompanies with increased risk of new onset of type 2 diabetes, however, the underlying mechanisms remain not be fully understood and effective prevention strategies are still lacking. Herein, we find that both pharmacological and genetic inhibition of GGTase II mimic the disruption of simvastatin on hepatic insulin signaling and glucose metabolism in vitro. AAV8-mediated knockdown of liver RABGGTA, the specific subunit of GGTase II, triggers systemic glucose metabolism disorders in vivo. By adopting a small-scale siRNA screening, we identify RAB14 as a regulator of hepatic insulin signaling and glucose metabolism. Geranylgeranylation deficiency of RAB14 inhibits the phosphorylation of AKT (Ser473) and disrupts hepatic insulin signaling and glucose metabolism possibly via impeding mTORC2 complex assembly. Finally, geranylgeranyl pyrophosphate (GGPP) supplementation is sufficient to prevent simvastatin-caused disruption of hepatic insulin signaling and glucose metabolism in vitro. Geranylgeraniol (GGOH), a precursor of GGPP, is able to ameliorate simvastatin-induced systemic glucose metabolism disorders in vivo. In conclusion, our data indicate that statins-targeted mevalonate pathway regulates hepatic insulin signaling and glucose metabolism via geranylgeranylation of RAB14. GGPP/GGOH supplementation might be an effective strategy for the prevention of the diabetic effects of statins.

Comparative Analysis of Clavien-Dindo Grade and Risk Factors of Complications after Dual-Port Laparoscopic Distal Gastrectomy and Hand-Assisted Laparoscopic Gastrectomy

Objective

To compare the Clavien–Dindo grade and risk factors of complications after dual-port laparoscopic distal gastrectomy (DPLDG) and hand-assisted laparoscopic gastrectomy (HALG).

Methods

The clinical data of 775 patients who underwent DPLDG or HALG in our hospital from May 2016 to May 2019 were retrospectively reviewed, and the patients were divided into the DPLDG group (n = 386) and HALG group (n = 389) according to the surgical method to explore the risk factors of postoperative complications by grading their postoperative complications according to the Clavien–Dindo classification system and single-factor and multivariate analysis of the association between variables in clinical data and complications.

Results

Compared with the HALG group, the DPLDG group had significantly shorter surgical time, less intraoperative blood loss, and better postoperative exhaust time (p < 0.05), with no significant difference in other clinical indicators between the two groups (p > 0.05); the postoperative complication incidence rate of DPLDG group was significantly lower than that of the HALG group; it was shown in the single-factor analysis that the age, tumor length, intraoperative blood loss, pathological stages, and surgical method were related to the postoperative complications, and the results of multivariate analysis indicated that DPLDG was the protective factor for reducing postoperative complications, while age no less than 60 years old and intraoperative blood loss no less than 180 ml were the independent risk factors leading to complications; after surgery, the PNI level values at T1, T2, and T3 of DPLDG group were significantly higher than those of the HALG group (p < 0.05); and at 1 month after surgery, both groups obtained significantly higher GLQI scores than before, and the GLQI score of the DPLDG group was significantly higher in the between-group comparison (p < 0.05).

Conclusion

The DPLDG has lower postoperative complication incidence rate than the HALG, but age no less than 60 years old and intraoperative blood loss not less than 180 ml are the independent risk factors for postoperative complications, so advanced prevention measures shall be taken to lower the incidence of complications.

Rab GTPases: Central Coordinators of Membrane Trafficking in Cancer

Tumor progression involves invasion, migration, metabolism, autophagy, exosome secretion, and drug resistance. Cargos transported by membrane vesicle trafficking underlie all of these processes. Rab GTPases, which, through coordinated and dynamic intracellular membrane trafficking alongside cytoskeletal pathways, determine the maintenance of homeostasis and a series of cellular functions. The mechanism of vesicle movement regulated by Rab GTPases plays essential roles in cancers. Therefore, targeting Rab GTPases to adjust membrane trafficking has the potential to become a novel way to adjust cancer treatment. In this review, we describe the characteristics of Rab GTPases; in particular, we discuss the role of their activation in the regulation of membrane transport and provide examples of Rab GTPases regulating membrane transport in tumor progression. Finally, we discuss the clinical implications and the potential as a cancer therapeutic target of Rab GTPases.

Exosomal miR-2276-5p in Plasma Is a Potential Diagnostic and Prognostic Biomarker in Glioma

Introduction

Exosomal microRNAs (miRNAs) play an essential role in near and distant intercellular communication and are potential diagnostic and prognostic biomarkers for various cancers. This study focused on evaluation of exosomal miR-2276-5p in plasma as a diagnostic and prognostic biomarker for glioma.

Methods

Plasma exosomes from 124 patients with glioma and 36 non-tumor controls were collected and subjected to quantitative real-time polymerase chain reaction (qRT-PCR) analysis for the exosomal miR-2276-5p expression. Bioinformatic analyses were performed to identify a gene target, and CGGA and TCGA databases were checked for evaluation of prognostic relevance.

Results

The exosomal miR-2276-5p in glioma patients had a significantly decreased expression, compared with non-glioma patients (p < 0.01). Receiver operating characteristics (ROC) curve analyses were observed to regulate the diagnostic sensitivity and specificity of miR-2276-5p in glioma; the area under the curve (AUC) for miR-2276-5p was 0.8107. The lower expression of exosomal miR-2276-5p in patients with glioma correlated with poorer survival rates. RAB13 was identified as the target of miR-2276-5p which was high in glioma patients, especially those with higher tumor grades and correlated with poor survival.

Conclusion

The circulating exosomal miR-2276-5p is significantly reduced in the plasma of glioma patients, and thus, it could be a potential biomarker for patients with glioma for diagnostic and/or prognostic purposes.

Rab13 and Desmosome Redistribution in Uterine Epithelial Cells During Early Pregnancy

The luminal uterine epithelial cells are the first point of contact with the implanting blastocyst. Dramatic changes occur in the structure and function of these cells at the time of receptivity including changes in the lateral junctional complex. While these morphological changes are important for uterine receptivity, currently there is no known mechanism of regulation of the lateral junctional complexes. Rab13, a member of the Rab (Ras-related in the brain) family of GTPases has a critical role in endosomal trafficking to the lateral plasma membrane and is involved in modulation of the tight junction in several cell types. The aim of this study is to investigate the role of Rab13 in changes to the lateral junctional complex at the time of receptivity. Immunofluorescence microscopy demonstrated no association between Rab13 and ZO-1 (a tight junction protein) or Rab13 and E-cadherin (an integral component of adherens junctions). Co-localisation was demonstrated between Rab 13 and desmoglein-2 at the time of fertilization and also at receptivity suggesting involvement of Rab13 in relocalisation of desmoglein-2 and formation of giant desmosomes in the apical part of the lateral plasma membrane at the time of uterine receptivity. We suggest that despite the loss of the adherens junction at the time of receptivity, the presently reported redistribution of desmosomes regulated by Rab13 allows the uterine epithelium to maintain structural integrity.

MAP Kinases Pathways in Gastric Cancer

Gastric cancer (GC) is turning out today to be one of the most important welfare issues for both Asian and European countries. Indeed, while the vast majority of the disease burden is located in China and in Pacific and East Asia, GC in European countries still account for about 100,000 deaths per year. With this review article, we aim to focus the attention on one of the most complex cellular pathways involved in GC proliferation, invasion, migration, and metastasis: the MAP kinases. Such large kinases family is to date constantly studied, since their discovery more than 30 years ago, due to the important role that it plays in the regulation of physiological and pathological processes. Interactions with other cellular proteins as well as miRNAs and lncRNAs may modulate their expression influencing the cellular biological features. Here, we summarize the most important and recent studies involving MAPK in GC. At the same time, we need to underly that, differently from cancers arising from other tissues, where MAPK pathways seems to be a gold target for anticancer therapies, GC seems to be unique in any aspect. Our aim is to review the current knowledge in MAPK pathways alterations leading to GC, including H. pylori MAPK-triggering to derail from gastric normal epithelium to GC and to encourage researches involved in MAPK signal transduction, that seems to definitely sustain GC development.

A Novel lncRNA MYOSLID/miR-1286/RAB13 Axis Plays a Critical Role in Osteosarcoma Progression

Background

Osteosarcoma (OS) is a quite malignant bone cancer. However, how long noncoding RNA (lncRNA) regulates OS progression remains poorly investigated. The present study aims to illustrate the potential functions of lncRNA MYOSLID in the regulation of OS progression.

Methods

The expression of YOSLID, miR-1286 and RAB13 was analyzed by qRT-PCR. Cell proliferation was determined via CCK8 and colony formation assays. Transwell assay was used to examine migration and invasion. The luciferase reporter assay, RNA pulldown and RNA immunoprecipitation (RIP) assays were utilized to detect the interactions among MYOSLID, miR-1286 and RAB13.

Results

The expression of MYOSLID was upregulated in OS tissues and cell lines. MYOSLID overexpression predicted poor prognosis in OS patients. MYOSLID knockdown suppressed proliferation, migration and invasion of OS cells. MYOSLID was the sponge for miR-1286 and inhibited its expression while miR-1286 targeted RAB13 directly. MYOSLID promoted RAB13 expression via sponging miR-1286.

Conclusion

Our work demonstrated that the MYOSLID/miR-1286/RAB13 axis is a novel regulatory signaling in promoting OS progression.