Afadin Downregulation by Helicobacter pylori Induces Epithelial to Mesenchymal Transition in Gastric Cells

AFDN Deficiency Promotes Liver Tropism of Metastatic Colorectal Cancer

Liver metastasis is a major cause of morbidity and mortality in patients with colorectal cancer. A better understanding of the biological mechanisms underlying liver tropism and metastasis in colorectal cancer could help to identify improved prevention and treatment strategies. In this study, we performed genome-wide CRISPR loss-of-function screening in a mouse colorectal cancer model and identified deficiency of AFDN, a protein involved in establishing and maintaining cell-cell contacts, as a driver of liver metastasis. Elevated AFDN expression was correlated with prolonged survival in patients with colorectal cancer. AFDN-deficient colorectal cancer cells preferentially metastasized to the liver but not in the lungs. AFDN loss in colorectal cancer cells at the primary site promoted cancer cell migration and invasion by disrupting tight intercellular junctions. Additionally, CXCR4 expression was increased in AFDN-deficient colorectal cancer cells via the JAK-STAT signaling pathway, which reduced the motility of AFDN-deficient colorectal cancer cells and facilitated their colonization of the liver. Collectively, these data shed light on the mechanism by which AFDN deficiency promotes liver tropism in metastatic colorectal cancer. Significance: A CRISPR screen reveals AFDN loss as a mediator of liver tropism in colorectal cancer metastasis by decreasing tight junctions in the primary tumor and increasing interactions between cancer cells and hepatocytes.

Autophagy induced by Helicobacter Pylori infection can lead to gastric cancer dormancy, metastasis, and recurrence: new insights

According to the findings of recent research, Helicobacter Pylori (H. pylori) infection is not only the primary cause of gastric cancer (GC), but it is also linked to the spread and invasion of GC through a number of processes and factors that contribute to virulence. In this study, we discussed that H. pylori infection can increase autophagy in GC tumor cells, leading to poor prognosis in such patients. Until now, the main concerns have been focused on H. pylori's role in GC development. According to our hypothesis, however, H. pylori infection may also lead to GC dormancy, metastasis, and recurrence by stimulating autophagy. Therefore, understanding how H. pylori possess these processes through its virulence factors and various microRNAs can open new windows for providing new prevention and/or therapeutic approaches to combat GC dormancy, metastasis, and recurrence which can occur in GC patients with H. pylori infection with targeting autophagy and eradicating H. pylori infection.

Helicobacter pylori-induced fibroblast-derived Serpin E1 promotes gastric cancer growth and peritoneal dissemination through p38 MAPK/VEGFA-mediated angiogenesis

BACKGROUND

Fibroblasts, especially cancer-associated fibroblasts (CAFs), represent the predominant stromal cell population in the tumor microenvironment and have an important function in tumorigenesis by interacting with tumor cells. However, their interaction remains elusive in an inflammatory tumor microenvironment induced by Helicobacter pylori (H. pylori).

METHODS

The expression of Serpin family E member 1 (Serpin E1) was measured in fibroblasts with or without H. pylori infection, and primary gastric cancer (GC) cells. Serpin E1 knockdown and overexpression fibroblasts were generated using Serpin E1 siRNA or lentivirus carrying Serpin E1. Co-culture models of fibroblasts and GC cells or human umbilical vein endothelial cells (HUVECs) were established with direct contact or the Transwell system. In vitro functional experiments and in vivo tumorigenesis assay were employed to study the malignant behaviors of GC cells interacting with fibroblasts. ELISA was used for quantifying the levels of Serpin E1 and VEGFA in the culture supernatant. The tube formation capacity of HUVECs was assessed using a tube formation assay. Recombinant human Serpin E1 (recSerpin E1), anti-Serpin E1 antibody, and a MAPK pathway inhibitor were utilized to treat HUVECs for elucidating the underlying molecular mechanisms.

RESULTS

Serpin E1 was predominantly expressed in gastric CAFs. H. pylori infection significantly enhanced the expression and secretion of Serpin E1 by CAFs. Both fibroblast-derived Serpin E1 and recSerpin E1 enhanced the growth, invasion, and migration of GC cells, along with increased VEGFA expression and tube formation in HUVECs. Furthermore, the co-inoculation of GC cells and fibroblasts overexpressing Serpin E1 triggered the expression of Serpin E1 in cancer cells, which facilitated together xenograft tumor growth and peritoneal dissemination of GC cells in nude mice, with an increased expression of Ki67, Serpin E1, CD31 and/or VEGFA. These processes may be mediated by Serpin E1-induced migration and p38 MAPK/VEGFA-mediated angiogenesis of HUVECs.

CONCLUSION

H. pylori infection induces Serpin E1 expression in fibroblasts, subsequently triggering its expression in GC cells through their interaction. Serpin E1 derived from these cells promotes the migration and p38 MAPK/VEGFA-mediated angiogenesis of HUVECs, thereby facilitating GC growth and peritoneal metastasis. Targeting Serpin E1 signaling is a potential therapy strategy for H. pylori-induced GC.

Exploring the Role of the Gut and Intratumoral Microbiomes in Tumor Progression and Metastasis

Cancer cell dissemination involves invasion, migration, resistance to stressors in the circulation, extravasation, colonization, and other functions responsible for macroscopic metastases. By enhancing invasiveness, motility, and intravasation, the epithelial-to-mesenchymal transition (EMT) process promotes the generation of circulating tumor cells and their collective migration. Preclinical and clinical studies have documented intensive crosstalk between the gut microbiome, host organism, and immune system. According to the findings, polymorphic microbes might play diverse roles in tumorigenesis, cancer progression, and therapy response. Microbial imbalances and changes in the levels of bacterial metabolites and toxins promote cancer progression via EMT and angiogenesis. In contrast, a favorable microbial composition, together with microbiota-derived metabolites, such as short-chain fatty acids (SCFAs), can attenuate the processes of tumor initiation, disease progression, and the formation of distant metastases. In this review, we highlight the role of the intratumoral and gut microbiomes in cancer cell invasion, migration, and metastatic ability and outline the potential options for microbiota modulation. As shown in murine models, probiotics inhibited tumor development, reduced tumor volume, and suppressed angiogenesis and metastasis. Moreover, modulation of an unfavorable microbiome might improve efficacy and reduce treatment-related toxicities, bringing clinical benefit to patients with metastatic cancer.

Early onset, development and histological features of gastric signet-ring cell carcinoma

Objective

To explore the early onset, development and histological features of gastric signet-ring cell carcinoma (SRCC).

Methods

Three hundred and sixty-two patients with differentiated adenocarcinoma with signet-ring cells were enrolled. Histomorphological and immunohistochemical features and patterns of the specimens were observed in detail.

Results

Infection of the gastric mucosa, especially by Helicobacter pylori, can cause massive cell proliferation and transformation in the deep gastric foveola, the isthmus of the gastric gland, and the proliferative zone of the upper neck of the gland. Signet-ring-like heterocysts monoclonally proliferated after the redifferentiation and reproliferation, extending horizontally along the gastric foveola. Gastric foveolar-type SRCC grew infiltratively into the lamina propria of the mucosa and the submucosa, signet-ring cells could differentiate into undifferentiated adenocarcinoma with signet-ring cell differentiation, mucinous adenocarcinoma with signet-ring cell differentiation, gastric adenocarcinoma with signet-ring cell differentiation, and fundus gland adenocarcinoma with signet-ring cell differentiation.

Conclusion

Early SRCC developed from the proliferative zones of the fundus of the gastric foveola and the neck of the gastric gland, growing horizontally along the gastric foveola. It developed into gastric adenocarcinoma with signet-ring cell differentiation after reproliferation and retransformation in the mucosa.

Gastric Epithelial Barrier Disruption, Inflammation and Oncogenic Signal Transduction by Helicobacter pylori

Helicobacter pylori exemplifies one of the most favourable bacterial pathogens worldwide. The bacterium colonizes the gastric mucosa in about half of the human population and constitutes a major risk factor for triggering gastric diseases such as stomach cancer. H. pylori infection represents a prime example of chronic inflammation and cancer-inducing bacterial pathogens. The microbe utilizes a remarkable set of virulence factors and strategies to control cellular checkpoints of inflammation and oncogenic signal transduction. This chapter emphasizes on the pathogenicity determinants of H. pylori such as the cytotoxin-associated genes pathogenicity island (cagPAI)-encoded type-IV secretion system (T4SS), effector protein CagA, lipopolysaccharide (LPS) metabolite ADP-glycero-β-D-manno-heptose (ADP-heptose), cytotoxin VacA, serine protease HtrA, and urease, and how they manipulate various key host cell signaling networks in the gastric epithelium. In particular, we highlight the H. pylori-induced disruption of cell-to-cell junctions, pro-inflammatory activities, as well as proliferative, pro-apoptotic and anti-apoptotic responses. Here we review these hijacked signal transduction events and their impact on gastric disease development.

Histopathological Features of Helicobacter pylori Infection in Gastric Mucosa

Objective

To investigate the histopathological characteristics of Helicobacter pylori (Hp) infection in the gastric mucosa in the process from occurrence to intraepithelial neoplasia.

Methods

Specimens obtained from the endoscopic biopsy and endoscopic submucosal dissection of 2457 cases of gastric Hp infection were observed and assessed in detail using histology and immunohistochemistry techniques. The condition was divided according to the histopathological characteristics of gastric mucosal damage caused by Hp infection. The histopathological characteristics and immunophenotype of each stage were subsequently elucidated.

Results

Helicobacter pylori is initially implanted in the mucus layer covered by the epithelium on the surface of the gastric mucosa. It then selectively adheres to the cytoplasm of the surface mucus cells, which makes the oval and spherical particles containing mucus that is wrapped by the bounded membrane in the cytoplasm on the nucleus of the surface mucus cells disappear, while the cytoplasm undergoes spiderweb-like vacuolar degeneration. This leads to the proliferation and transformation of the surface mucous cells before developing into intraepithelial neoplasia. In the process of histomorphology, mucosal ulcers, mucosal lymphoid tissue proliferation, gland atrophy, intestinal epithelial metaplasia, mucosa-associated lymphoid tissue lymphoma, and adenocarcinoma may occur. In this study, the condition was divided into five stages according to the histopathological characteristics of gastric mucosal damage caused by Hp infection, as well as the degree of gastric mucosal damage and involvement depth as follows: the mucus infection stage, the surface epithelial cell infection stage, the lamina propria lesion stage, the mucosal atrophy stage, and the intraepithelial neoplasia stage.

Conclusion

Understanding the histopathological characteristics of gastric Hp infection in terms of its occurrence and development into intraepithelial neoplasia is conducive to the precise treatment and tracking of malignant cell transformation, and is of great significance in controlling the occurrence and development of gastric cancer.

Clinicopathological characteristics of signet-ring cell carcinoma derived from gastric fovelar epithelium

OBJECTIVE

We aimed to investigate the immunophenotype, differential diagnosis, and clinicopathological characteristics of signet-ring cell carcinoma (SRCC) derived from gastric foveolar epithelium.

METHODS

Clinical characteristics, endoscopic findings, histopathological features, and follow-up data of seven cases of SRCC derived from gastric foveolar epithelium with small intramucosal lesions were analyzed.

RESULTS

Seven patients with a mean age of 38.3 years were diagnosed with SRCC derived from gastric foveolar epithelium and small intramucosal lesions, all of them were negative for CDH-1 germline mutation. The glands proliferated and expanded, and then morphologically transformed into signet-ring cells and formed clonal hyperplastic SRCC, which expanded laterally along the gastric foveolar cells to a length of 3-6 mm. Periodic acid Schiff staining was positive, while CK7 and MUC6 were negative, in all cases. Ki-67-positive cells ranged 37%-60%. During a follow-up period of 6-30 months, no patients experienced tumor recurrence or metastasis.

CONCLUSIONS

SRCC derived from gastric foveolar epithelium is originated from the proliferative region of the bottom of the gastric pit and gland neck. It is easily missed diagnosed or misdiagnosed as it grows laterally along the gastric foveolar cells. Biological behavior, genetics, and etiology of such SRCC, as well as the clinicopathological characteristics, need to be further studied.

Intestinal Alkaline Phosphatase Prevents Sulfate Reducing Bacteria-Induced Increased Tight Junction Permeability by Inhibiting Snail Pathway

Tight junctions (TJs) are essential components of intestinal barrier integrity and protect the epithelium against passive paracellular flux and microbial translocation. Dysfunctional TJ leads to leaky gut, a condition associated with diseases including inflammatory bowel disease (IBD). Sulfate-Reducing Bacteria (SRB) are minor residents of the gut. An increased number of Desulfovibrio, the most predominant SRB, is observed in IBD and other diseases associated with leaky gut. However, it is not known whether Desulfovibrio contributes to leaky gut. We tested the hypothesis that Desulfovibrio vulgaris (DSV) may induce intestinal permeability in vitro. Snail, a transcription factor, disrupts barrier function by affecting TJ proteins such as occludin. Intestinal alkaline phosphatase (IAP), a host defense protein, protects epithelial barrier integrity. We tested whether DSV induced permeability in polarized Caco-2 cells via snail and if this effect was inhibited by IAP. Barrier integrity was assessed by measuring transepithelial electric resistance (TEER) and by 4kDa FITC-Dextran flux to determine paracellular permeability. We found that DSV reduced TEER, increased FITC-flux, upregulated snail protein expression, caused nuclear translocation of snail, and disrupted occludin staining at the junctions. DSV-induced permeability effects were inhibited in cells knocked down for snail. Pre-treatment of cells with IAP inhibited DSV-induced FITC flux and snail expression and DSV-mediated disruption of occludin staining. These data show that DSV, a resident commensal bacterium, can contribute to leaky gut and that snail may serve as a novel therapeutic target to mitigate DSV-induced effects. Taken together, our study suggests a novel underlying mechanism of association of Desulfovibrio bloom with diseases with increased intestinal permeability. Our study also underscores IAP as a novel therapeutic intervention for correcting SRB-induced leaky gut via inhibition of snail.

Influence of a Polyherbal Choline Source in Dogs: Body Weight Changes, Blood Metabolites, and Gene Expression

Choline chloride is used to provide choline in dog foods; however, in other domestic species, it has been replaced with a polyherbal containing phosphatidylcholine. A polyherbal containing Achyrantes aspera, Trachyspermum ammi, Citrullus colocynthis, Andrographis paniculata, and Azadirachta indica was evaluated in adult dogs through body weight changes, subcutaneous fat thickness, blood metabolites, and gene expression. Forty dogs (4.6 ± 1.6 years old) who were individually housed in concrete kennels were randomly assigned to the following treatments: unsupplemented diet (377 mg choline/kg), choline chloride (3850 mg/kg equivalent to 2000 mg choline/kg diet), and polyherbal (200, 400, and 800 mg/kg) for 60 days. Blood samples were collected on day 59 for biochemistry, biometry, and gene expression analysis through microarray assays. Intake, final body weight, and weight changes were similar for the two choline sources. Feed intake variation among dogs (p = 0.01) and dorsal fat (p = 0.03) showed a quadratic response to herbal choline. Dogs that received the polyherbal diet had reduced blood cholesterol levels (Quadratic, p = 0.02). The gene ontology analysis indicated that 15 biological processes were modified (p ≤ 0.05) with implications for preventing cardiovascular and metabolic diseases, cancer prevention, inflammatory and immune response, and behavior and cognitive process. According to these results that were observed in a 60 day trial, the polyherbal form could replace choline chloride in dog diets at a concentration of 400 mg/kg.

Helicobacter pylori PqqE is a new virulence factor that cleaves junctional adhesion molecule A and disrupts gastric epithelial integrity

Helicobacter pylori infects approximately half of the world's population and is the strongest risk factor for peptic ulcer disease and gastric cancer, representing a major global health concern. H. pylori persistently colonizes the gastric epithelium, where it subverts the highly organized structures that maintain epithelial integrity. Here, a unique strategy used by H. pylori to disrupt the gastric epithelial junctional adhesion molecule-A (JAM-A) is disclosed, using various experimental models that include gastric cell lines, primary human gastric cells, and biopsy specimens of infected and non-infected individuals. H. pylori preferentially cleaves the cytoplasmic domain of JAM-A at Alanine 285. Cells stably transfected with full-length JAM-A or JAM-A lacking the cleaved sequence are used in a range of functional assays, which demonstrate that the H. pylori cleaved region is critical to the maintenance of the epithelial barrier and of cell-cell adhesion. Notably, by combining chromatography techniques and mass spectrometry, PqqE (HP1012) is purified and identified as the H. pylori virulence factor that cleaves JAM-A, uncovering a previously unreported function for this bacterial protease. These findings propose a novel mechanism for H. pylori to disrupt epithelial integrity and functions, breaking new ground in the understanding of the pathogenesis of this highly prevalent and clinically relevant infection.

The protein-protein interaction network of intestinal gastric cancer patients reveals hub proteins with potential prognostic value

BACKGROUND

Gastric cancer (GC) is the third leading cause of cancer worldwide. According to the Lauren classification, gastric adenocarcinoma is divided into two subtypes: diffuse and intestinal. The development of intestinal gastric cancer (IGC) can take years and involves multiple factors.

OBJECTIVE

To investigate the protein profile of tumor samples from patients with IGC in comparison with adjacent nontumor tissue samples.

METHODS

We used label-free nano-LC-MS/MS to identify proteins from the tissues samples. The results were analyzed using MetaCore™ software to access functional enrichment information. Protein-protein interactions (PPI) were predicted using STRING analysis. Hub proteins were determined using the Cytoscape plugin, CytoHubba. Survival analysis was performed using KM plotter. We identified 429 differentially expressed proteins whose pathways and processes were related to protein folding, apoptosis, and immune response.

RESULTS

The PPI network of these proteins showed enrichment modules related to the regulation of cell death, immune system, neutrophil degranulation, metabolism of RNA and chromatin DNA binding. From the PPI network, we identified 20 differentially expressed hub proteins, and assessed the prognostic value of the expression of genes that encode them. Among them, the expression of four hub genes was significantly associated with the overall survival of IGC patients.

CONCLUSIONS

This study reveals important findings that affect IGC development based on specific biological alterations in IGC patients. Bioinformatics analysis showed that the pathogenesis of IGC patients is complex and involves different interconnected biological processes. These findings may be useful in research on new targets to develop novel therapies to improve the overall survival of patients with IGC.

Gastric Cancer: Advances in Carcinogenesis Research and New Therapeutic Strategies

Gastric cancer’s bad incidence, prognosis, cellular and molecular heterogeneity amongst others make this disease a major health issue worldwide. Understanding this affliction is a priority for proper patients’ management and for the development of efficient therapeutical strategies. This review gives an overview of major scientific advances, made during the past 5-years, to improve the comprehension of gastric adenocarcinoma. A focus was made on the different actors of gastric carcinogenesis, including, Helicobacter pylori cancer stem cells, tumour microenvironment and microbiota. New and recent potential biomarkers were assessed as well as emerging therapeutical strategies involving cancer stem cells targeting as well as immunotherapy. Finally, recent experimental models to study this highly complex disease were discussed, highlighting the importance of gastric cancer understanding in the hard-fought struggle against cancer relapse, metastasis and bad prognosis.

Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment

Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.

Afadin (AF6) in cancer progression: A multidomain scaffold protein with complex and contradictory roles

Adherens (AJ) and tight junctions (TJ) maintain cell-cell adhesions and cellular polarity in normal tissues. Afadin, a multi-domain scaffold protein, is commonly found in both adherens and tight junctions, where it plays both structural and signal-modulating roles. Afadin is a complex modulator of cellular processes implicated in cancer progression, including signal transduction, migration, invasion, and apoptosis. In keeping with the complexities associated with the roles of adherens and tight junctions in cancer, afadin exhibits both tumor suppressive and pro-metastatic functions. In this review, we will explore the dichotomous roles that afadin plays during cancer progression.

Hyaluronic Acid of Low Molecular Weight Triggers the Invasive "Hummingbird" Phenotype on Gastric Cancer Cells

The overproduction and deposition of hyaluronic acid (HA) of different sizes in the tumor microenvironment is associated with cancer metastasis. Here, the development of layer-by-layer (LbL) constructs containing HA of different molecular weights (i.e., 5.6, 618, and 1450 kDa) that mimic the HA-rich cancer extracellular matrix is described to study the effect of the HA's size on the behavior of gastric cancer cells (AGS). The results demonstrate that LbL constructs with short HA, i.e., 5.6 kDa, activate the cytoskeleton rearrangement leading to the "hummingbird" morphology, promote high cellular motility, and activate signaling pathways with increased expression of p-ERK1/2 and p-AKT. In addition, it is demonstrated that this malignant transformation involves an active participation of the HA coreceptor RHAMM in AGS cells.

TAZ Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Cancer Stem Cell-Like Invasive and Tumorigenic Properties

Helicobacter pylori infection, the main risk factor for gastric cancer (GC), leads to an epithelial–mesenchymal transition (EMT) of gastric epithelium contributing to gastric cancer stem cell (CSC) emergence. The Hippo pathway effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ) control cancer initiation and progression in many cancers including GC. Here, we investigated the role of TAZ in the early steps of H. pylori-mediated gastric carcinogenesis. TAZ implication in EMT, invasion, and CSC-related tumorigenic properties were evaluated in three gastric epithelial cell lines infected by H. pylori. We showed that H. pylori infection increased TAZ nuclear expression and transcriptional enhancer TEA domain (TEAD) transcription factors transcriptional activity. Nuclear TAZ and zinc finger E-box-binding homeobox 1 (ZEB1) were co-overexpressed in cells harboring a mesenchymal phenotype in vitro, and in areas of regenerative hyperplasia in gastric mucosa of H. pylori-infected patients and experimentally infected mice, as well as at the invasive front of gastric carcinoma. TAZ silencing reduced ZEB1 expression and EMT phenotype, and strongly inhibited invasion and tumorsphere formation induced by H. pylori. In conclusion, TAZ activation in response to H. pylori infection contributes to H. pylori-induced EMT, invasion, and CSC-like tumorigenic properties. TAZ overexpression in H. pylori-induced pre-neoplastic lesions and in GC could therefore constitute a biomarker of early transformation in gastric carcinogenesis.

Mechanisms of the Epithelial-Mesenchymal Transition and Tumor Microenvironment in Helicobacter pylori-Induced Gastric Cancer

Helicobacter pylori (H. pylori) is one of the most common human pathogens, affecting half of the world’s population. Approximately 20% of the infected patients develop gastric ulcers or neoplastic changes in the gastric stroma. An infection also leads to the progression of epithelial–mesenchymal transition within gastric tissue, increasing the probability of gastric cancer development. This paper aims to review the role of H. pylori and its virulence factors in epithelial–mesenchymal transition associated with malignant transformation within the gastric stroma. The reviewed factors included: CagA (cytotoxin-associated gene A) along with induction of cancer stem-cell properties and interaction with YAP (Yes-associated protein pathway), tumor necrosis factor α-inducing protein, Lpp20 lipoprotein, Afadin protein, penicillin-binding protein 1A, microRNA-29a-3p, programmed cell death protein 4, lysosomal-associated protein transmembrane 4β, cancer-associated fibroblasts, heparin-binding epidermal growth factor (HB-EGF), matrix metalloproteinase-7 (MMP-7), and cancer stem cells (CSCs). The review summarizes the most recent findings, providing insight into potential molecular targets and new treatment strategies for gastric cancer.

The Cancer Microbiota: EMT and Inflammation as Shared Molecular Mechanisms Associated with Plasticity and Progression

With the advent of novel molecular platforms for high-throughput/next-generation sequencing, the communities of commensal and pathogenic microorganisms that inhabit the human body have been defined in depth. In the last decade, the role of microbiota-host interactions in driving human cancer plasticity and malignant progression has been well documented. Germ-free preclinical models provided an invaluable tool to demonstrate that the human microbiota can confer susceptibility to various types of cancer and can also modulate the host response to therapeutic treatments. Of interest, besides the detrimental effects of dysbiosis on cancer etiopathogenesis, specific microorganisms have been shown to exert protective activities against cancer growth. This has strong clinical implications, as restoration of the physiologic microbiota is being rapidly implemented as a novel anticancer therapeutic strategy. Here, we reviewed past and recent literature depicting the role of microbiota-host interactions in modulating key molecular mechanisms that drive human cancer plasticity and lead to malignant progression. We analyzed microbiota-host interactions occurring in the gut as well as in other anatomic sites, such as oral and nasal cavities, lungs, breast, esophagus, stomach, reproductive tract, and skin. We revealed a common ground of biological alterations and pathways modulated by a dysbiotic microbiota and potentially involved in the control of cancer progression. The molecular mechanisms most frequently affected by the pathogenic microorganisms to induce malignant progression involve epithelial-mesenchymal transition- (EMT-) dependent barrier alterations and tumor-promoting inflammation. This evidence may pave the way to better stratify high-risk cancer patients based on unique microenvironmental/microbial signatures and to develop novel, personalized, biological therapies.

Review: Gastric malignancies: Basic aspects

Gastric cancer is the third deadliest cancer in the world, and the absolute number of cases is increasing every year due to aging and growing of high-risk populations. This disease is a consequence of the complex interaction of microbial agents, with environmental and host factors, resulting in the dysregulation of multiple oncogenic and tumor-suppressing signaling pathways. Despite the advances in our understanding of carcinogenesis, there are still reduced therapeutic options for patients with gastric cancer. In recent years, genomic analyses of gastric tumors have emphasized their molecular heterogeneity. The distinction of gastric cancer molecular subtypes may be a key to identify novel therapeutic targets, to predict patient outcome and response to therapy, and to guide early diagnosis strategies. In this review, we summarize the most recent updates on the relationship between microbial agents and gastric cancer, in particular, Helicobacter pylori, the non-H pylori microbiome, and Epstein-Barr virus. We also highlight the main advances made in the past year regarding the molecular characterization of gastric cancer, especially the signatures with potential clinical utility.

A Polarizing Issue: Diversity in the Mechanisms Underlying Apico-Basolateral Polarization In Vivo

Polarization along an apico-basolateral axis is a hallmark of epithelial cells and is essential for their selective barrier and transporter functions, as well as for their ability to provide mechanical resiliency to organs. Loss of polarity along this axis perturbs development and is associated with a wide number of diseases. We describe three steps involved in polarization: symmetry breaking, polarity establishment, and polarity maintenance. While the proteins involved in these processes are highly conserved among epithelial tissues and species, the execution of these steps varies widely and is context dependent. We review both theoretical principles underlying these steps and recent work demonstrating how apico-basolateral polarity is established in vivo in different tissues, highlighting how developmental and physiological contexts play major roles in the execution of the epithelial polarity program.