Helicobacter pylori-infected MSCs acquire a pro-inflammatory phenotype and induce human gastric cancer migration by promoting EMT in gastric cancer cells

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.

Immunological Aspects of the Tumor Microenvironment and Epithelial-Mesenchymal Transition in Gastric Carcinogenesis

Infection with Helicobacter pylori, a Gram-negative, microaerophilic pathogen often results in gastric cancer in a subset of affected individuals. This explains why H. pylori is the only bacterium classified as a class I carcinogen by the World Health Organization. Several studies have pinpointed mechanisms by which H. pylori alters signaling pathways in the host cell to cause diseases. In this article, the authors have reviewed 234 studies conducted over a span of 18 years (2002-2020). The studies investigated the various mechanisms associated with gastric cancer induction. For the past 1.5 years, researchers have discovered new mechanisms contributing to gastric cancer linked to H. pylori etiology. Alongside alteration of the host signaling pathways using oncogenic CagA pathways, H. pylori induce DNA damage in the host and alter the methylation of DNA as a means of perturbing downstream signaling. Also, with H. pylori, several pathways in the host cell are activated, resulting in epithelial-to-mesenchymal transition (EMT), together with the induction of cell proliferation and survival. Studies have shown that H. pylori enhances gastric carcinogenesis via a multifactorial approach. What is intriguing is that most of the targeted mechanisms and pathways appear common with various forms of cancer.

Mesenchymal stem cells co-cultured with colorectal cancer cells showed increased invasive and proliferative abilities due to its altered p53/TGF-β1 levels

Signaling between cancer cells, their neighboring cells, and mesenchymal stem cells (MSCs) forms the tumor microenvironment. The complex heterogeneity of this microenvironment varies depending on the tumor type and its origins. However, most of the existing cancer-based studies have focused on cancer cells. In this study, we used a direct co-culture system (cross-talk signaling) to induce cross-interaction between cancer cells and mesenchymal stem cells. This induced deformation of MSCs. MSCs showed a diminished ability to maintain homeostasis. In particular, increase in the invasion ability of MSCs by TGF-β1 and decrease in p53, which plays a key role in cancer development, is an important discovery. It can thus be deduced that blocking these changes can effectively inhibit metastatic colorectal cancer. In conclusion, understanding the interactions and changes in MSCs associated with cancer will help develop novel therapeutic strategies for cancer.

Effects of Celastrus orbiculatus on Epithelial Mesenchymal Transition in Gastric Mucosal Epithelial Cells by Inhibiting Lgr5 Expression from Rats with Gastric Precancerous Lesions

The extract of Celastrus orbiculatus (COE) has been shown to possess anti-Helicobacter pylori (H. pylori) activity and anticancer effects in vitro and in vivo. However, the molecular mechanism by which COE on precancerous lesions of gastric cancer (PLGC) has not been fully elucidated so far. The purpose of this study is to evaluate the effect and mechanism of COE in the rat model of PLGC, after the rat model of PLGC was successfully constructed. The effects of COE in gastric mucosa of rats with PLGC were tested using routine pathology and a transmission electron microscope (TEM) analysis. The protein and mRNA expression levels of epithelial mesenchymal transition (EMT) markers (E-cadherin, N-cadherin and Vimentin) and leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) were detected adopting techniques of immunohistochemistry (IHC), real-time PCR (RT-PCR) and western blot assays. The body weight of PLGC rats was significantly higher in the COE group than that in the untreated group. The process of PLGC was significantly reversed after COE treatment, shown by observing the changes of histopathological morphology and ultrastructure. Gastric mucosal epithelial cells in COE high dose (COE-H) group showed significantly higher expression levels of E-cadherin, and lower expression levels of N-cadherin, Vimentin and Lgr5 than those of the untreated group. COE could suppress the spatial distribution of Lgr5[Formula: see text] cell changes in PLGC rats. These findings suggested that the therapeutic mechanisms of COE in treating PLGC might be related with its effects on reversing the EMT process and inhibiting Lgr5 expression.

The future of mesenchymal stem cell-based therapeutic approaches for cancer - From cells to ghosts

Mesenchymal stem cells (MSCs) are multipotent stromal cells which can differentiate into a variety of cell types including osteoblasts, adipocytes and chondrocytes. They are normally resident in adipose tissue, bone marrow and the umbilical cord, but can also be found in other tissues and are known to be recruited to sites of wound healing as well as growing tumours. The therapeutic potential of MSCs has been explored in a number of phase I/II and III clinical trials, of which several were targeted against graft-versus-host disease and to support engraftment of haematopoietic stem cells (HSCs), but currently only very few in the oncology field. There are now three clinical trials either ongoing or recruiting patients that use MSCs to treat tumour disease. In these, MSCs target gastrointestinal, lung and ovarian cancer, respectively. The first study uses MSCs loaded with a HSV-TK expression construct under the control of the CCL5 promoter, and has recently reported successful completion of Phase I/II. While no adverse side effects were seen during this study, no outcomes with respect to therapeutic benefits have been published. The other clinical trials targeting lung and ovarian cancer will be using MSCs expressing cytokines as therapeutic payload. Despite these encouraging early steps towards their clinical use, many questions are still unanswered regarding the biology of MSCs in normal and pathophysiological settings. In this review, in addition to summarising the current state of MSC-based therapeutic approaches for cancer, we will describe the remaining questions, obstacles and risks, as well as novel developments such as MSC-derived nanoghosts.

IL-17B activated mesenchymal stem cells enhance proliferation and migration of gastric cancer cells

Mesenchymal stem cells are important cells in tumor microenvironment. We have previously demonstrated that IL-17B/IL-17RB signal promoted progression of gastric cancer. In this study, we further explored the effect of IL-17B on mesenchymal stem cells in tumor microenvironment and its impact on the tumor progression. The results showed that IL-17B induced the expression of stemness-related genes Nanog, Sox2, and Oct4 in mesenchymal stem cells and enhanced its tumor-promoting effect. The supernatant from cultured mesenchymal stem cells after treating with exogenous rIL-17B promoted the proliferation and migration of MGC-803, therefor suggesting that rIL-17B might promote mesenchymal stem cells to produce soluble factors. In addition, rIL-17B also activated the NF-κΒ, STAT3, β-catenin pathway in mesenchymal stem cells. Our data revealed a new mechanism that IL-17B enhanced the progression of gastric cancer by activating mesenchymal stem cells.

TGFβ1-Induced LncRNA UCA1 Upregulation Promotes Gastric Cancer Invasion and Migration

According to recent studies, long noncoding RNA urothelial carcinoma associated 1 (UCA1) is involved in the development and progression of many malignant tumors, including gastric cancer (GC). We validated the detailed role of UCA1 in human GC cell lines and GC tissues so as to determine its exact function and the underlying mechanism of GC invasion and migration. In our research, lncRNA-UCA1 was specifically upregulated in GC tissues and cell lines, and augmented GC cell proliferation, and invasive and migratory capabilities. High UCA1 expression in GC was related with poorer prognosis (poorer invasion depth, lymph node metastasis, advanced TNM [T is for the original (primary) tumor, N for nearby (regional) lymph nodes that are involved, and M for distant metastasis] stage, and shorter overall survival). Epithelial mesenchymal transition (EMT), associated with malignancy of cancers, was reported to be responsible for invasion and migration of cancer cells. Transforming growth factor β1 (TGFβ1)-induced EMT was well evaluated. UCA1 silence reduced the protein levels of EMT-related factors, vimentin and snail, while promoted E-cadherin and zonula occludens-1 protein levels in GC cells; the effect of UCA1 could be partly restored by TGFβ1 treatment. Taken together, UCA1 might regulate the tumor proliferation, invasion, and metastasis under TGFβ1 induction. Taken together, UCA1 might present a potential oncogenic factor by promoting GC cell proliferation, invasion, and migration. UCA1 could serve as a novel biomarker for prognosis and a novel therapeutic target of GC treatment.

Re-evaluating the role of epithelial-mesenchymal-transition in cancer progression

Epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) are essential for embryonic development and also important in cancer progression. In a conventional model, epithelial-like cancer cells transit to mesenchymal-like tumor cells with great motility via EMT transcription factors; these mesenchymal-like cells migrate through the circulation system, relocate to a suitable site and then convert back to an epithelial-like phenotype to regenerate the tumor. However, recent findings challenge this conventional model and support the existence of a stable hybrid epithelial/mesenchymal (E/M) tumor population. Hybrid E/M tumor cells exhibit both epithelial and mesenchymal properties, possess great metastatic and tumorigenic capacity and are associated with poorer patient prognosis. The hybrid E/M model and associated regulatory networks represent a conceptual change regarding tumor metastasis and organ colonization. It may lead to the development of novel treatment strategies to ultimately stop cancer progression and improve disease-free survival.

Effect of mesenchymal stem cells on proliferation and chemotherapeutic resistance of human gastric cancer cells SGC7901 in vivo

AIM

To investigate the effect of bone marrow mesenchymal stem cells (MSCs) on the proliferation and chemotherapeutic resistance of gastric cancer cells SGC7901.

METHODS

SGC7901 cells and primary bone marrow MSCs were cultured in vitro. Nude mice were divided into two groups and received subcutaneous injection of SGC7901cells alone and SGC7901 cells plus bone marrow MSCs, respectively. After the tumors grew up to 250-400 mm³, each group was further randomly divided into two groups and received intraperitoneal injection of 5-fluorouridine (5-Fu) and normal saline (NS), respectively. The four groups were as follows: SGC7901 + NS (group A), SGC7901 + MSCs + NS (group B), SGC7901 + Fu (group C), and SGC7901 + MSCs + Fu (group D). All the nude mice were sacrificed on days 18 after 9 intraperitoneal injections. Tumor volume, tumor weight, and net weight of nude mice were measured at the end of the experiment, and pathological changes of tumors were detected under an inverted microscope.

RESULTS

The differences in tumor volume, tumor weight, and net weight of mice were significant between each group. MSCs increased the proliferation ability and 5-Fu resistance of SGC7901 cells, but under the same conditions (5-Fu+/-), the net weight of nude mice in the SGC7901 + MSC group was significantly more than that of the SGC7901 group.

CONCLUSION

MSC can not only enhance the proliferation and 5-Fu resistance of transplanted SGC7901 cells, but also improve the nutritional condition of nude mice simultaneously.