ObjectiveTo summarizes the mechanisms of carcinogenesis of colorectal cells, the occurrence and development of cancer cells, and their interactions with the tumor niche of colorectal cancer (CRC) from the perspective of the tumor niche, exploring new ideas for the prevention, diagnosis, and treatment of CRC. MethodThe relevant literature at home and abroad in recent years on the researches of mechanism of the occurrence and development of CRC and its relation with the tumor niche of CRC was searched and reviewed. ResultsThe theory of tumor ecology indicates that the human normal body can be regarded as a relatively closed and perfect ecosystem. Each normal tissue and organ within the body represent a niche in this ecosystem, which interact, affect, and symbiotically coexist with each other, forming a dynamic ecological balance. Tumor cells, being a “new species” distinct from normal tissue cells, “invade” the ecological system of the normal body under specific conditions and interact with the surrounding microenvironment, which is defined as the tumor niche. Analysis of current literature retrieved from the perspective of the tumor niche suggested that, although genetic factors are involved in the carcinogenesis of colorectal cells, the majority of such carcinogenesis stems from the continuous stimulation of the colorectal niche. Current research primarily focuses on the conclusion that the carcinogenesis of colorectal cells is associated with factors such as chronic inflammatory response, intestinal microorganisms, oxidative stress, and pyroptosis. After carcinogenesis and the eventual formation of CRC, the growth of cancer cells and tissues first requires breaching the defense of the immune system in the colorectal niche. Immune cells in the immune system play a crucial role in the tumor niche during the occurrence and development of CRC. ConclusionsThe proposal of the tumor niche concept enables researchers, when studying the mechanisms of tumor occurrence and development, to no longer merely focus on the tumor and its microenvironment. Instead, the tumor as a part of the body’s ecosystem was studied. Components of the tumor niche, such as chronic inflammatory responses, intestinal microorganisms, oxidative stress, pyroptosis, and immune system, have a significant impact on the mechanisms of carcinogenesis of most colorectal cells, as well as the occurrence and development of cancer cells. These factors influence the progression of CRC in various aspects.
Objective To investigate relationship between hypoxia microenvironment and occurrence and development of hepatocellular carcinoma (HCC). Method The relevant literatures on researches of the relationship between the hypoxic microenvironment and the HCC were review and analyzed. Results The hypoxia microenvironment played an important role in inducing the drug resistance and angiogenesis of the HCC cells, and it was an important factor of affecting the ability of tumor metabolism, invasion, and migration. The hypoxia microenvironment could up-regulate the expression of hypoxia-inducible factors (HIFs) and promote its transcriptional activity, promote the expression of the vascular endothelial growth factor gene, and regulate the neovascularization in the tumor. Among them, the HIF-1α played a major role in regulating the angiogenesis, immune escape, tumor invasion and metastasis-related gene expression, participating in the glycolysis, regulating lysyl oxidase 2 and thus regulated epithelial-mesenchymal transition, then promoted the invasion and metastasis of the HCC; HIF-2α was a key regulator of the malignant phenotype involving in the cell proliferation, angiogenesis, apoptosis, metabolism, metastasis, and resistance to chemotherapy. The hypoxia microenvironment posed some difficulties for the treatment of HCC, but it was also a potential therapeutic breakthrough. Conclusion Hypoxia microenvironment can promote invasion and metastasis of HCC through various mechanisms, which provides new targets and strategies for clinical treatment of HCC.
ObjectiveTo review cancer associated fibroblasts(CAFs) and its role in the evolution of gastrointestinal neoplasms. MethodDomestic and international publications in relation to CAFs and its role in the evolution of gastrointestinal neoplasms were collected and reviewed. ResultsIn the gastrointestinal cancers, as the largest number and the most important stromal cells of the tumor microenvironment, CAFs induce the homeostasis of cell microenviron-ment out of balance, promote the remodeling of the tumor metabolism and extracellular matrix(ECM), and thus impulse the generation, proliferation, invasion and metastasis of the tumor by secreting different kinds of cytokines. ConclusionsThe key role CAFs playing in the tumor generation and evolution makes themselves and the multiple relatively specific molecules they secrete a new target for prognosis and targeted therapy, and this gives us a new idea for the combined treatment of gastrointestinal tumor or any other tumors.
ObjectiveTo introduce the research status of the immunoregulation function of cancer-associated fibroblasts (CAFs) in tumor microenvironment.MethodThe literatures in recent years on the studies of role of CAFs in the regulation of immune response in the tumor microenvironment were collected and summarized.ResultsThe CAFs played a critical role as the components of the tumor microenvironment. The CAFs could product various growth factors and cytokines that were contributed to the immunoregulation including the polarization of the immune cells and the regulation of the function of immune cells in the tumor microenvironment and eventually resulted in the carcinogenesis, tumor progression, invasion, metastasis and therapy resistance.ConclusionCAFs play a significant role in the immunoregulation in tumor microenvironment, but as a potential target for breast cancer, more studies are still needed to discover the specific markers, heterogeneity, and key signaling pathways.
In the tumor microenvironment, tumor-associated macrophage, as polarized macrophages M2 phenotype, can promote tumor progression and affect the prognosis of cancer. Significant attention has been drawn towards tumor-associated macrophage in recent years. In this review, we describe the polarization state of macrophages determined by tumor microenvironment and the recruitment of tumor-associated macrophage. We also pay special attention to the interaction between tumor-associated macrophages and tumors, discuss and summarize various targeted therapy strategies for tumor-associated macrophages, aiming to provide a reference for the future development of these novel and effective anti-cancer treatments.
ObjectiveTo summarize the relationship between exosomes and the occurrence and development of gastrointestinal cancer.MethodsThrough online database, we collected the literatures about the relationship between exosomes and the development of gastrointestinal cancer at home and abroad, and then made an review.ResultsExosomes secreted by gastrointestinal cancer cells were related to tumorigenesis, tumor cell survival, chemoresistance, and early metastasis. Exosomes could play the role of information transmission, and regulation of cell physiology and pathological process in the development of gastrointestinal cancer through a variety of intercellular binding ways, and affectted the occurrence and development of gastrointestinal cancer via epigenetic regulation and tumor related signal transduction mechanism. They had been proved to be biomarkers, targets, and drug carriers for the treatment of gastrointestinalcancer.ConclusionIt is a new way to explore the molecular mechanism of exosomes in the development of gastrointestinal cancer.
Objective To introduce the research status of the immunomodulatory role of various immune cells and stromal cells in the tumor microenvironment in the progression of hepatocellular carcinoma. Method The related basic and clinical research literatures on the correlation between various immune cells and stromal cells in the tumor microenvironment and the occurrence, development and prognosis of hepatocellular carcinoma were reviewed and summarized. Results Immune cells and stromal cells in the tumor microenvironment have obvious complexity and diversity. Inhibitory immune cells in various immunosuppressive environments and stimulating immune cells that exert anti-tumor effects jointly promote or inhibit the occurrence and progression of hepatocellular carcinoma. Conclusions The exact role of various immune cells in the tumor microenvironment in hepatocellular carcinoma remains to be further studied. With the continuous accumulation of relevant research results, more patients with hepatocellular carcinoma will benefit from immunotherapy.
ObjectiveTo summarize the molecular mechanisms and clinical treatment of gastric cancer with liver metastasis (GCLM), in order to provide new ideas for future treatment. MethodThe literatures about mechanism and treatment strategy of GCLM in recent years were searched and reviewed. ResultsMost patients with gastric cancer were in advanced stage or had developed distant metastases when they were first diagnosed, among which liver was the common site of metastasis. The complex molecular mechanisms of GCLM had not been fully clarified. Molecular mechanisms at different levels, including non-coding RNA, circulating tumor cells, exosomes, tumor microenvironment and signaling pathways, were relatively independent and interacted with each other, providing potential biomarkers and therapeutic targets for GCLM. At present, the best treatment method for patients with GCLM was mainly divided into local and systemic treatment. The local treatment included surgical treatment, radiofrequency ablation and proton beam therapy, while the systemic treatment included systemic chemotherapy, targeted therapy and immunotherapy, among which the targeted therapy and immunotherapy were the focus of recent research. ConclusionsThe mechanism of GCLM is the result of the interaction between tumor cells and the microenvironment at the site of metastasis. Understanding them is of great significance to guide clinical treatment and prognosis. At present, there is no unified treatment standard for GCLM. To achieve the ideal treatment effect, we should not only rely on single therapy, but also adopt multi-disciplinary and individual therapy according to the specific disease status of patients and the nature of tumors.
ObjectiveTo investigate the effect of ubiquitin specific peptidase 22 (USP22) on the occurrence and development of esophageal squamous cell carcinoma (ESCC) under hypoxic conditions, and its regulatory relationship with hypoxia inducible factor-1α (HIF-1α). MethodsWestern blotting and quantitative polymerase chain reaction (qPCR) were used to detect the differences in USP22 protein and mRNA expression between normal esophageal epithelial cells HEEC and ESCC cell lines KYSE30, KYSE150, EC9706, and TE-1 under normoxic (5% CO2, 20% O2, 75% N2) and hypoxic (5% CO2, 1% O2, 94% N2) conditions. By transfecting USP22 plasmid or siUSP22, ESCC cells were divided into a normoxia control group, a normoxia+USP22 group, a normoxia+siUSP22 group, a hypoxia control group, a hypoxia+USP22 group, and a hypoxia+siUSP22 group. The proliferation and migration abilities of cells in each group were detected. The expression of USP22 and HIF-1α under hypoxic conditions after up-regulating or down-regulating USP22 was detected, and their regulatory relationship was verified. The interaction between USP22 and HIF-1α was verified by co-immunoprecipitation (Co-IP) technique. ResultsCompared with HEEC cells, the expression of USP22 in ESCC cells was significantly increased (P<0.05). Up-regulation of USP22 expression promoted the proliferation and migration of ESCC cells, while silencing USP22 inhibited the proliferation and migration of ESCC cells (P<0.05). Under hypoxic conditions, the expression of USP22 and HIF-1α increased, and with the up-regulation of USP22 expression, the expression of HIF-1α also significantly increased (P<0.05). Co-IP experiment confirmed the binding between USP22 and HIF-1α. ConclusionUp-regulation of USP22 expression promotes the proliferation and migration of ESCC cells. Hypoxia microenvironment can induce the increase of USP22 expression in ESCC. USP22 may participate in the regulation of the occurrence and development of ESCC by directly binding to HIF-1α.
ObjectiveTo review the research advances about myeloid derived suppressor cells(MDSC)and pancreatic cancer, and explore the future research trends. MethodRelated literatures in recent 5 years from abroad databases(PubMed, Web of Science, and EMBASE)and domestic databases(CNKI, WANFANG, and WEIPU)were collected and reviewed. ResultsThe MDSC was the core of tumor immune regulation network in pancreatic cancer microenvironment, it formed a complicated feedback with the pancreatic cancer and the stellate cells. MDSC could promote the cancerogensis and progression of pancreatic cancer, and the accumulation of MDSC in peripheral blood of pancreatic cancer patient could predict the poor prognosis. However up to now, the literatures about the relation between MDSC and the chemotherapy and metastasis of pancreatic cancer were limited. ConclusionsThe comprehensive therapy by targeting MDSC of pancreatic cancer is promising. However, many issues need to be further investigated.