AQP5 complements LGR5 to determine the fates of gastric cancer stem cells through regulating ULK1 ubiquitination

Development of novel prognostic protein signatures in ovarian cancer: Molecular structure and immune function of AQP5 protein and CTDP1 protein

Ovarian cancer is a serious gynecological malignancy, and early identification of prognostic markers is critical to improve clinical outcomes. Aquaporin 5 (AQP5) and cell cycle regulatory protein CTDP1 are considered as potential prognostic protein markers, but their specific molecular structure and immune function have not been thoroughly studied. The aim of this study was to investigate the molecular structure of AQP5 and CTDP1 and their immune function in ovarian cancer, to evaluate their potential as prognostic markers, and to provide new ideas for the diagnosis and efficacy monitoring of ovarian cancer. Cox regression analysis and LASSO regression were used to construct the risk prognosis model, and the preliminary verification was carried out. Finally, cell culture and high-resolution gene expression analysis were used to investigate the expression of AQP5 and CTDP1 and their roles in the immune microenvironment. The results showed that AQP5 and CTDP1 were highly expressed in ovarian cancer cell lines and were closely related to tumor immune invasion. The immunomicroenvironment analysis based on GRN showed that they showed a positive correlation with tumor-related immune cells. Through the constructed risk model, AQP5 and CTDP1 significantly affect patient prognosis, suggesting their potential as prognostic markers.

Advances and challenges in gastric cancer testing: the role of biomarkers

Advances in the identification of molecular biomarkers and the development of targeted therapies have enhanced the prognosis of patients with advanced gastric cancer. Several established biomarkers have been widely integrated into routine clinical diagnostics of gastric cancer to guide personalized treatment. Human epidermal growth factor receptor 2 (HER2) was the first molecular biomarker to be used in gastric cancer with trastuzumab being the first approved targeted therapy for HER2-positive gastric cancer. Programmed death-ligand 1 positivity and microsatellite instability can guide the use of immunotherapies, such as pembrolizumab and nivolumab. More recently, zolbetuximab has been approved for patients with claudin 18.2-positive diseases in some countries. More targeted therapies, including savolitinib for MET-positive patients, are currently under clinical investigation. However, the clinical application of these diagnostic approaches could be hampered by many existing challenges, including invasive and costly sampling methods, variability in immunohistochemistry interpretation, high costs and long turnaround times for next-generation sequencing, the absence of standardized and clinically validated diagnostic cut-off values for some biomarkers, and tumor heterogeneity. Novel testing and analysis techniques, such as artificial intelligence-assisted image analysis and multiplex immunohistochemistry, and emerging therapeutic strategies, including combination therapies that integrate immune checkpoint inhibitors with targeted therapies, offer potential solutions to some of these challenges. This article reviews recent progress in gastric cancer testing, outlines current challenges, and explores future directions for biomarker testing and targeted therapy for gastric cancer.

Identification of an extracellular matrix signature for predicting prognosis and sensitivity to therapy of patients with gastric cancer

Extracellular matrix (ECM) is a vital component of the tumor microenvironment and plays a crucial role in the development and progression of gastric cancer (GC). Co-expression networks were established by means of the "WGCNA" package, the optimal model for extracellular matrix scores (ECMs) was developed and validated, with its accuracy in predicting the prognosis and treatment sensitivity of GC patients assessed. We performed univariate cox regression analysis [HR = 6.8 ( 3.3-14 ), p < 0.001] which demonstrated that ECMs was an independent risk character and perceptibly superior to other factors with further analysis of multivariate Cox regression [HR = 8.68 ( 4.16-18.08 ), p < 0.001]. The nomogram, presenting the clinical prognosis model for GC patients, demonstrated accuracy through KM analysis [HR = 3.97 (2.56-6.16), p < 0.001] and ROC curves with AUC values of 0.70, 0.72, and 0.72 at 1, 3, and 5 years, respectively. Using the ECMs model, we stratified GC patients into high- and low-risk groups, enabling precise predictions of prognosis and drug sensitivity. This stratification provides a new strategic direction for the personalized treatment of GC.

YTHDF2-mediated m6A modification of ONECUT2 promotes stemness and oxaliplatin resistance in gastric cancer through transcriptionally activating TFPI

AIMS

Chemoresistance results in poor outcomes of patients with gastric cancer (GC). This study aims to identify oxaliplatin resistance-related cell subpopulations in the tumor microenvironment (TME) and decipher the involved molecular mechanisms.

METHODS

Through single-cell RNA sequencing, a unique ONECUT2+TFPI+ GC cell subset was identified in the oxaliplatin-resistant TME. The functional roles and molecular mechanisms of ONECUT2 in oxaliplatin resistance were investigated in cellular and mouse models. Therapeutic efficacy of small molecule inhibitor of ONECUT2 was also evaluated.

RESULTS

The abundance of ONECUT2+TFPI+ GC cell subset was elevated in oxaliplatin-resistant GC tumors. ONECUT2 was up-regulated and associated with undesirable prognostic outcomes of patients with GC. ONECUT2 facilitated GC cell migration, stemness properties and oxaliplatin resistance. YTHDF2, an m6A "reader", was down-regulated in GC, and its overexpression facilitated ONECUT2 mRNA degradation through m6A modification. Furthermore, ONECUT2 transcriptionally activated TFPI through binding to its promoter. Small molecule inhibitor CSRM617 targeting ONECUT2 was well tolerated in GC mouse models, and could effectively improve therapeutic efficacy of oxaliplatin against GC.

CONCLUSIONS

Our study demonstrates that YTHDF2-mediated m6A modification of ONECUT2 results in stemness and oxaliplatin resistance in GC through transcriptionally activating TFPI, which provides a novel therapeutic target against oxaliplatin-resistant GC.

Single-cell RNA-sequencing and genome-wide Mendelian randomisation along with abundant machine learning methods identify a novel B cells signature in gastric cancer

BACKGROUND

Gastric cancer (GC) has a poor prognosis, considerable cellular heterogeneity, and ranks fifth among malignant tumours. Understanding the tumour microenvironment (TME) and intra-tumor heterogeneity (ITH) may lead to the development of novel GC treatments.

METHODS

The single-cell RNA sequencing (scRNA-seq) dataset was obtained from the Gene Expression Omnibus (GEO) database, where diverse immune cells were isolated and re-annotated based on cell markers established in the original study to ascertain their individual characteristics. We conducted a weighted gene co-expression network analysis (WGCNA) to identify genes with a significant correlation to GC. Utilising bulk RNA sequencing data, we employed machine learning integration methods to train specific biomarkers for the development of novel diagnostic combinations. A two-sample Mendelian randomisation study was performed to investigate the causal effect of biomarkers on gastric cancer (GC). Ultimately, we utilised the DSigDB database to acquire associations between signature genes and pharmaceuticals.

RESULTS

The 18 genes that made up the signature were as follows: ZFAND2A, PBX4, RAMP2, NNMT, RNASE1, CD93, CDH5, NFKBIE, VWF, DAB2, FAAH2, VAT1, MRAS, TSPAN4, EPAS1, AFAP1L1, DNM3. Patients were categorised into high-risk and low-risk groups according to their risk scores. Individuals in the high-risk cohort exhibited a dismal outlook. The Mendelian randomisation study demonstrated that individuals with a genetic predisposition for elevated NFKBIE levels exhibited a heightened likelihood of acquiring GC. Molecular docking indicates that gemcitabine and chloropyramine may serve as effective therapeutics against NFKBIE.

CONCLUSIONS

We developed and validated a signature utilising scRNA-seq and bulk sequencing data from gastric cancer patients. NFKBIE may function as a novel biomarker and therapeutic target for GC.

PGD2/PTGDR2 signaling pathway affects the self-renewal capacity of gastric cancer stem cells by regulating ATG4B ubiquitination

Background

Prostaglandin D2 (PGD2) inhibits the development of different malignant tumors; however, the underlying mechanism of inhibiting tumor development is not yet clear. This study aimed to elucidate how PGD2 inhibits the stemness of gastric cancer stem cells (GCSCs) via autophagy and its underlying molecular mechanism to provide a theoretical basis for the treatment of gastric cancer.

Methods

In this study, GCSCs were enriched in vitro by serum-free incubation. Furthermore, the effects of PGD2 and PGD2 receptor (PTGDR2) on autophagy were detected by Western blotting, immunofluorescence analysis, and transmission electron microscopy. Moreover, the ATG4B ubiquitination levels were assessed via immunoprecipitation and other methods.

Results

The results indicated that PGD2 induced LC3I/LC3II conversion in GCSCs to activate autophagy, while PGD2 promoted the expression of PTGDR2, thereby further activating autophagy. Furthermore, PTGDR2 competes with ATG4B for binding with E3 ligase RNF5 (also known as RMA1) to promote autophagy protein ATG4B expression. Moreover, PTGDR2 knockdown blocked the activation of autophagy by PGD2 and the level of ATG4B ubiquitination in GCSCs.

Conclusions

In summary, it was elucidated that the PGD2/PTGDR2 signaling cascade affects GCSCs stemness by regulating autophagy, suggesting that the PGD2/PTGDR2 signaling pathway could serve as a novel target for cancer therapy.

Identification of gastric cancer stem cells with CD44 and Lgr5 double labelling and their initial roles on gastric cancer malignancy and chemotherapy resistance

Accumulating evidences have indicated that cancer stem cells (CSCs) can initiate tumor progression and cause recurrence after therapy. However, specific markers of gastric CSCs (GCSCs) from different origins have not been comprehensively revealed. Here, we further detected whether cell populations labelled with CD44 and Lgr5, well-recognized stem markers for gastric cancer (GC), can better emphasize cancer initiation, therapeutic resistance and recurrence. Flow cytometry was utilized to sort the CD44 + Lgr5 + and CD44 + Lgr5- cells from GC cell line HGC-27 and primary GC cells. The influences of CD44 and Lgr5 GCSCs on the malignant behaviors and their potential mechanisms was investigated, respectively. In our study, we reported the identification and validation of CD44 + Lgr5 + cells that presented stronger stemness characteristics, as evidenced by increase of sphere forming ability, elevation of stem cell transcriptional activity. Additionally, CD44 + Lgr5 + double positive cells have lower apoptosis, greater chemotherapy resistance, and higher EMT capacity and LC3 density compared with CD44 + Lgr5- cells. Tumor xenograft experiments also verified the faster carcinogenesis of CD44 + Lgr5 + GCSCs. Furthermore, a series of key proteins in the Wnt, Hedgehog, Notch, and TGF-β pathways were elevated in the CD44 + Lgr5 + double positive subpopulation, except for Notch 1 and Smad 1. In conclusion, the binding of CD44 and Lgr5 can serve as a precise GCSCs marker that initiate malignant progression and chemotherapy resistance in GC by activating Wnt, Hedgehog, Notch, TGF-β pathways. Those evidences raise the needs to target both markers simultaneously as a potential approach for the GC treatment.

Combined single cell and spatial transcriptome analysis reveals cellular heterogeneity of hedgehog pathway in gastric cancer

Gastric cancer (GC) is one of the most common and deadly malignancies in the world. Abnormal activation of hedgehog pathway is closely related to tumor development and progression. However, potential therapeutic targets for GC based on the hedgehog pathway have not been clearly identified. In the present study, we combined single-cell sequencing data and spatial transcriptomics to deeply investigate the role of hedgehog pathway in GC. Based on a comprehensive scoring algorithm, we found that fibroblasts from GC tumor tissues were characterized by a highly enriched hedgehog pathway. By analyzing the development process of fibroblasts, we found that CCND1 plays an important role at the end stage of fibroblast development, which may be related to the formation of tumor-associated fibroblasts. Based on spatial transcriptome data, we deeply mined the role of CCND1 in fibroblasts. We found that CCND1-negative and -positive fibroblasts have distinct characteristics. Based on bulk transcriptome data, we verified that highly infiltrating CCND1 + fibroblasts are a risk factor for GC patients and can influence the immune and chemotherapeutic efficacy of GC patients. Our study provides unique insights into GC and hedgehog pathways and also new directions for cancer treatment strategies.

Integration of single-cell sequencing and bulk transcriptome data develops prognostic markers based on PCLAF+ stem-like tumor cells using artificial neural network in gastric cancer

Background

Gastric cancer stem cells (GCSCs) are important tumour cells involved in tumourigenesis and gastric cancer development. However, their clinical value remains unclear due to the limitations of the available technologies. This study aims to explore the clinical significance of GCSCs, their connection to the tumour microenvironment, and their underlying molecular mechanisms.

Methods

Stem-like tumour cells were identified by mining single-cell transcriptomic data from multiple samples. Integrated analysis of single-cell and bulk transcriptome data was performed to analyse the role of stem-like tumour cells in predicting clinical outcomes by introducing the intermediate variable mRNA stemness degree (SD). Consensus clustering analysis was performed to develop an SD-related molecular classification strategy to assess the clinical characteristics in gastric cancer. A prognostic model was constructed using a customized approach that comprehensively considered SD-related gene signatures based on an artificial neural network.

Results

By analysing single-cell data and validating immunofluorescence results, we identified a PCLAF+ stem-like tumour cell population in GC. By calculating SD, we observed that PCLAF+ stem-like tumour cells were associated with poor prognosis and certain clinical features. The SD was negatively correlated with the abundance of most immune cell types. Furthermore, we proposed an SD-related classification method and prognostic model. In addition, the customised prognostic model can be used to predict whether a patient respond to PD-1/PD-L1 immunotherapy.

Conclusion

We identified a cluster of stem-like cells and elucidated their clinical significance, highlighting the possibility of their use as immunotherapeutic targets.

ISL1 and AQP5 complement each other to enhance gastric cancer cell stemness by regulating CD44 expression

Background

Gastric cancer, a prevalent and life-threatening malignancy, is believed to involve cancer stem cells (CSCs) as a contributing factor to tumor progression. Insulin gene enhancer binding protein-1 (ISL1) is a transcription factor, and it has not been elucidated how ISL1 regulates gastric carcinogenesis. The aim of this paper is to investigate the role of ISL1 in gastric cancer development.

Methods

In this study, we investigated the effects of ISL1 on the stem-like properties of human gastric cancer cells by applying transcriptional, flow, and immunofluorescence techniques.

Results

In human gastric cancer samples, there is an observed elevation in ISL1 expression, which correlates with the expression of stem cell markers, notably LGR5. Functionally, ISL1 fosters the self-renewal, cell proliferation, migration, and the clonogenic potential of gastric cancer cells in vitro. Furthermore, it enhances the ability of these cells to form tumors and metastasize in vivo. Additionally, ISL1 collaborates with AQP5, collectively intensifying the tumorigenicity of gastric cancer cells. Mechanistically, transcriptomic analysis of cells overexpressing ISL1 unveils a notable activation of the forkhead box O (FOXO) pathway. This activation leads to increased nuclear expression of forkhead box O3 (FOXO3), subsequently resulting in elevated expression of the stemness-associated gene CD44 in gastric cancer cells.

Conclusions

These findings shed light on the role of ISL1 in promoting the stem-like characteristics of gastric cancer cells and emphasize the connection between ISL1 and AQP5 as a novel therapeutic target for individuals with gastric cancer.

CCKBR+ cancer cells contribute to the intratumor heterogeneity of gastric cancer and confer sensitivity to FOXO inhibition

The existence of heterogeneity has plunged cancer treatment into a challenging dilemma. We profiled malignant epithelial cells from 5 gastric adenocarcinoma patients through single-cell sequencing (scRNA-seq) analysis, demonstrating the heterogeneity of gastric adenocarcinoma (GA), and identified the CCKBR+ stem cell-like cancer cells associated poorly differentiated and worse prognosis. We further conducted targeted analysis using single-cell transcriptome libraries, including 40 samples, to confirm these screening results. In addition, we revealed that FOXOs are involved in the progression and development of CCKBR+ gastric adenocarcinoma. Inhibited the expression of FOXOs and disrupting cancer cell stemness reduce the CCKBR+ GA organoid formation and impede tumor progression. Mechanically, CUT&Tag sequencing and Lectin pulldown revealed that FOXOs can activate ST3GAL3/4/5 as well as ST6GALNAC6, promoting elevated sialyation levels in CCKBR+ tumor cells. This FOXO-sialyltransferase axis contributes to the maintenance of homeostasis and the growth of CCKBR+ tumor cells. This insight provides novel perspectives for developing targeted therapeutic strategies aimed at the treating CCKBR associated gastric cancer.

Human umbilical cord mesenchymal stem cell-derived exosomes mitigate diabetic nephropathy via enhancing M2 macrophages polarization

Background and objectives

Exosomes, which are small nanoscale vesicles capable of secretion, have garnered significant attention in recent years because of their therapeutic potential, particularly in the context of kidney diseases. Notably, human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exos) are emerging as promising targeted therapies for renal conditions. The aim of this study was to investigate the therapeutic effects of hucMSC-Exos on diabetic kidney disease (DKD) both in vivo and in vitro. Additionally, this study seeks to elucidate cellular and molecular differentials, as well as the expression of relevant signaling pathways, through single-cell RNA sequencing. This endeavor was designed to enhance our understanding of the connection between hucMSC-Exos and the pathogenesis of DKD.

Methods and results

The study commenced with the extraction and characterization of hucMSC-Exos, including the determination of their concentrations. Animal experiments were conducted to evaluate the therapeutic potential of hucMSC-Exos in a DKD mouse model. Subsequently, single-cell sequencing was employed to investigate the molecular mechanisms underlying the efficacy of extracellular vesicles in ameliorating DKD. These findings were further substantiated by cell-based experiments. Importantly, the results indicate that hucMSC-Exos can impede the progression of DKD in mice, with macrophage activation playing a pivotal role in this process.

Conclusions

The in vivo experiments conclusively established hucMSC-Exos as a pivotal component in preserving renal function and retarding the progression of DKD. Our utilization of single-cell sequencing technology, in conjunction with in vivo and in vitro experiments, provides compelling evidence that M2 macrophages are instrumental in enhancing the amelioration of diabetic nephropathy.

Inflammation-Associated Stem Cells in Gastrointestinal Cancers: Their Utility as Prognostic Biomarkers and Therapeutic Targets

Stem cells are critical for the development and homeostasis of the gastrointestinal (GI) tract. Inflammatory molecules are known to regulate the activity of stem cells. A comprehensive review specifically describing the role of inflammatory molecules in the regulation of stem cells within the GI tract and in GI cancers (GICs) is not available. This review focuses on understanding the role of inflammatory molecules and stem cells in maintaining homeostasis of the GI tract. We further discuss how inflammatory conditions contribute to the transformation of stem cells into tumor-initiating cells. We also describe the molecular mechanisms of inflammation and stem cell-driven progression and metastasis of GICs. Furthermore, we report on studies describing the prognostic value of cancer stem cells and the clinical trials evaluating their therapeutic utility. This review provides a detailed overview on the role of inflammatory molecules and stem cells in maintaining GI tract homeostasis and their implications for GI-related malignancies.

Cancer-associated fibroblasts: a versatile mediator in tumor progression, metastasis, and targeted therapy

Tumor microenvironment (TME) has been demonstrated to play a significant role in tumor initiation, progression, and metastasis. Cancer-associated fibroblasts (CAFs) are the major component of TME and exhibit heterogeneous properties in their communication with tumor cells. This heterogeneity of CAFs can be attributed to various origins, including quiescent fibroblasts, mesenchymal stem cells (MSCs), adipocytes, pericytes, endothelial cells, and mesothelial cells. Moreover, single-cell RNA sequencing has identified diverse phenotypes of CAFs, with myofibroblastic CAFs (myCAFs) and inflammatory CAFs (iCAFs) being the most acknowledged, alongside newly discovered subtypes like antigen-presenting CAFs (apCAFs). Due to these heterogeneities, CAFs exert multiple functions in tumorigenesis, cancer stemness, angiogenesis, immunosuppression, metabolism, and metastasis. As a result, targeted therapies aimed at the TME, particularly focusing on CAFs, are rapidly developing, fueling the promising future of advanced tumor-targeted therapy.

Polyhedral magnetic nanoparticles induce apoptosis in gastric cancer stem cells and suppressing tumor growth through magnetic force generation

Gastric cancer is a prevalent malignant tumor worldwide, posing challenges due to its poor prognosis and limited treatment options. Cancer stem cells (CSCs) were demonstrated as a subset of cancer cells responsible for tumor initiation and progression, and their inherent resistance to conventional chemotherapy and radiotherapy critically contributes to tumor recurrence and metastasis. Promoting the eradication of cancer stem cells is crucial for enhancing the efficacy of cancer treatments. This study introduces a novel therapeutic strategy utilizing polyhedral magnetic nanoparticles (PMNPs) functionalized with CD44 antibodies and cell-penetrating peptides (CPPs) to improve uptake by gastric cancer stem cells (MCSCs). PMNPs, synthesized via thermal decomposition, exhibited a diameter of 90 nm ± 9 nm and a saturation magnetization of 79.9 emu/g. Functionalization enhanced their uptake capabilities. Under a rotating magnetic field (RMF) of 15 Hz, PMNPs disrupted cellular structure, leading to apoptosis and ferroptosis in MCSCs. The in vitro studies showed significant reduction in MCSCs viability, while in vivo studies demonstrated tumor growth suppression with minimal side effects and high biocompatibility. This work presents a novel strategy for designing magnetic nanoparticles to mechanically destroy cancer stem cells, offering a more efficient and safety treatment option for gastric cancer.

Single-cell sequencing analysis revealed that WDR72 was a novel cancer stem cells related gene in gastric cancer

Background

Cancer stem cells (CSCs) are pivotal in tumor resistance to chemotherapy and gastric cancer's rapid proliferation and metastasis. We aimed to explore the CSCs-related genes in gastric cancer epithelial cells.

Methods

The mRNA expression profile and single-cell sequencing data of gastric cancer were downloaded from the public database.

Results

We identified WDR72 as a CSCs-related gene in gastric cancer epithelial cells. WDR72 was highly expressed in gastric cancer tissues, and high expression of WDR72 was associated with inferior prognosis of patients. WDR72 expression had a significant negative correlation with the infiltration of CD8 + T cells and activated memory CD4 + T cells. PD-L1 expression was significantly reduced in gastric cancer patients with high WDR72 expression. WDR72 was correlated with IC50 of multiple small-molecule drugs.

Conclusion

We identified a novel CSCs-related gene in gastric cancer epithelial cells, WDR72, which was highly expressed in patients with high stemness scores.

Strategies for the Isolation and Identification of Gastric Cancer Stem Cells

Gastric cancer stem cells (GCSCs) originate from both gastric adult stem cells and bone marrow cells and are conspicuously present within the histological milieu of gastric cancer tissue. GCSCs play pivotal and multifaceted roles in the initiation, progression, and recurrence of gastric cancer. Hence, the characterization of GCSCs not only facilitates precise target identification for prospective therapeutic interventions in gastric cancer but also has significant implications for targeted therapy and the prognosis of gastric cancer. The prevailing techniques for GCSC purification involve their isolation using surface-specific cell markers, such as those identified by flow cytometry and immunomagnetic bead sorting techniques. In addition, in vitro culture and side-population cell sorting are integral methods in this context. This review discusses the surface biomarkers, isolation techniques, and identification methods of GCSCs, as well as their role in the treatment of gastric cancer.

Deciphering the Role of Exosomal Non-Coding RNA (ncRNA) in Drug Resistance of Gastrointestinal Tumors; an Updated Review

One of the most prevalent types of cancer worldwide today is gastric intestinal (GI) tumors. To guarantee their lives, people with a developed GI require palliative care. This covers the application of targeted medicines in addition to chemotherapy treatments including cisplatin, 5-fluorouracil, oxaliplatin, paclitaxel, and pemetrexed. Because of the evidence of drug resistance emerging in poor patient outcomes and prognoses, determining the exact process of medication resistance is motivated. Besides, it is noteworthy that exosomes and noncoding RNAs, like microRNAs and long non-coding RNAs (lncRNAs), produced from tumor cells are implicated in both GI medication resistance and the carcinogenesis and development of GI disease. Biochemical events related to the cell cycle, differentiation of cells, growth, and pluripotency, in addition to gene transcription, splicing, and epigenetics, are all regulated by noncoding RNAs (ncRNAs). Therefore, it should come as a wonder that several ncRNAs have been connected in recent years to drug susceptibility and resistance as well as tumorigenesis. Additionally, through communicating directly with medications, altering the transcriptome of tumor cells, and affecting the immune system, exosomes may govern treatment resistance. Because of this, exosomal lncRNAs often act as a competitive endogenous RNA (ceRNA) of miRNAs to carry out its role in modifying drug resistance. In light of this, we provide an overview of the roles and processes of ncRNA-enriched exosomes in GI medication resistance.

Microfluidic device featuring micro-constrained channels for multi-parametric assessment of cellular biomechanics and high-precision mechanical phenotyping of gastric cells

BACKGROUND

Cellular biomechanics plays a significant role in the regulation of cellular physiological and pathological processes. In recent years, multiple methods have been developed to evaluate cellular biomechanics, such as atomic force microscopy (AFM), micropipette aspiration, and magnetic tweezers. However, most of these methods only focus on a single parameter and cannot automate the process at a high-efficiency level. A novel microfluidic method is necessary to achieve the simultaneous multi-parametric measurement of cellular biomechanics and high-precision cellular mechanical phenotyping at high throughput.

RESULTS

To tackle the issue concerning the low-throughput and cellular single-parameter evaluation, we designed and fabricated a microfluidic chip featuring multiple micro-constrained channels structure, providing a simultaneous multi-parametric assessment of cellular biomechanics, including elastic modulus, recovery capability, and deformability. We compared the biomechanical properties of normal human gastric mucosal epithelial cells (GES-1) and human gastric cancer cells (AGS and MKN-45) by the chip. Results demonstrated that the elastic modulus of GES-1, AGS, and MKN-45 cells decreased sequentially, which was the opposite of their invasiveness and metastasis potential, suggesting the inverse correlation between cellular elastic modulus and malignancy. Meanwhile, the recovery capability and deformability of GES-1, AGS, and MKN-45 cells increased sequentially, demonstrating the positive correlation between cellular deformability and malignancy. Furthermore, multiple parameters were used to distinguish gastric cancer cells from normal gastric cells via machine learning. An accuracy of over 94.8% for identifying gastric cancer cells was achieved.

SIGNIFICANCE

This study provides a deep insight into the biophysical mechanism of gastric cancer metastasis at the single-cell level and possesses great potential to function as a valuable tool for single-cell analysis, thereby facilitating high-precision and high-throughput discrimination of cellular phenotypes that are not easily discernible through single-marker analysis.

Helicobacter pylori-activated fibroblasts as a silent partner in gastric cancer development

The discovery of Helicobacter pylori (Hp) infection of gastric mucosa leading to active chronic gastritis, gastroduodenal ulcers, and MALT lymphoma laid the groundwork for understanding of the general relationship between chronic infection, inflammation, and cancer. Nevertheless, this sequence of events is still far from full understanding with new players and mediators being constantly identified. Originally, the Hp virulence factors affecting mainly gastric epithelium were proposed to contribute considerably to gastric inflammation, ulceration, and cancer. Furthermore, it has been shown that Hp possesses the ability to penetrate the mucus layer and directly interact with stroma components including fibroblasts and myofibroblasts. These cells, which are the source of biophysical and biochemical signals providing the proper balance between cell proliferation and differentiation within gastric epithelial stem cell compartment, when exposed to Hp, can convert into cancer-associated fibroblast (CAF) phenotype. The crosstalk between fibroblasts and myofibroblasts with gastric epithelial cells including stem/progenitor cell niche involves several pathways mediated by non-coding RNAs, Wnt, BMP, TGF-β, and Notch signaling ligands. The current review concentrates on the consequences of Hp-induced increase in gastric fibroblast and myofibroblast number, and their activation towards CAFs with the emphasis to the altered communication between mesenchymal and epithelial cell compartment, which may lead to inflammation, epithelial stem cell overproliferation, disturbed differentiation, and gradual gastric cancer development. Thus, Hp-activated fibroblasts may constitute the target for anti-cancer treatment and, importantly, for the pharmacotherapies diminishing their activation particularly at the early stages of Hp infection.

Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease

Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.

B7-H3 confers stemness characteristics to gastric cancer cells by promoting glutathione metabolism through AKT/pAKT/Nrf2 pathway

BACKGROUND

Cancer stem-like cells (CSCs) are a small subset of cells in tumors that exhibit self-renewal and differentiation properties. CSCs play a vital role in tumor formation, progression, relapse, and therapeutic resistance. B7-H3, an immunoregulatory protein, has many protumor functions. However, little is known about the mechanism underlying the role of B7-H3 in regulating gastric cancer (GC) stemness. Our study aimed to explore the impacts of B7-H3 on GC stemness and its underlying mechanism.

METHODS

GC stemness influenced by B7-H3 was detected both in vitro and in vivo . The expression of stemness-related markers was examined by reverse transcription quantitative polymerase chain reaction, Western blotting, and flow cytometry. Sphere formation assay was used to detect the sphere-forming ability. The underlying regulatory mechanism of B7-H3 on the stemness of GC was investigated by mass spectrometry and subsequent validation experiments. The signaling pathway (Protein kinase B [Akt]/Nuclear factor erythroid 2-related factor 2 [Nrf2] pathway) of B7-H3 on the regulation of glutathione (GSH) metabolism was examined by Western blotting assay. Multi-color immunohistochemistry (mIHC) was used to detect the expression of B7-H3, cluster of differentiation 44 (CD44), and Nrf2 on human GC tissues. Student's t -test was used to compare the difference between two groups. Pearson correlation analysis was used to analyze the relationship between two molecules. The Kaplan-Meier method was used for survival analysis.

RESULTS

B7-H3 knockdown suppressed the stemness of GC cells both in vitro and in vivo . Mass spectrometric analysis showed the downregulation of GSH metabolism in short hairpin B7-H3 GC cells, which was further confirmed by the experimental results. Meanwhile, stemness characteristics in B7-H3 overexpressing cells were suppressed after the inhibition of GSH metabolism. Furthermore, Western blotting suggested that B7-H3-induced activation of GSH metabolism occurred through the AKT/Nrf2 pathway, and inhibition of AKT signaling pathway could suppress not only GSH metabolism but also GC stemness. mIHC showed that B7-H3 was highly expressed in GC tissues and was positively correlated with the expression of CD44 and Nrf2. Importantly, GC patients with high expression of B7-H3, CD44, and Nrf2 had worse prognosis ( P = 0.02).

CONCLUSIONS

B7-H3 has a regulatory effect on GC stemness and the regulatory effect is achieved through the AKT/Nrf2/GSH pathway. Inhibiting B7-H3 expression may be a new therapeutic strategy against GC.

The versatile roles of testrapanins in cancer from intracellular signaling to cell-cell communication: cell membrane proteins without ligands

The tetraspanins (TSPANs) are a family of four-transmembrane proteins with 33 members in mammals. They are variably expressed on the cell surface, various intracellular organelles and vesicles in nearly all cell types. Different from the majority of cell membrane proteins, TSPANs do not have natural ligands. TSPANs typically organize laterally with other membrane proteins to form tetraspanin-enriched microdomains (TEMs) to influence cell adhesion, migration, invasion, survival and induce downstream signaling. Emerging evidence shows that TSPANs can regulate not only cancer cell growth, metastasis, stemness, drug resistance, but also biogenesis of extracellular vesicles (exosomes and migrasomes), and immunomicroenvironment. This review summarizes recent studies that have shown the versatile function of TSPANs in cancer development and progression, or the molecular mechanism of TSPANs. These findings support the potential of TSPANs as novel therapeutic targets against cancer.