Exosome-mediated transfer of lncRNA HCG18 promotes M2 macrophage polarization in gastric cancer

Role of exosomal miRNAs and macrophage polarization in gastric cancer: A novel therapeutic strategy

Gastric cancer (GC) is one of the most common gastrointestinal cancers worldwide, with consistently high morbidity and mortality rates and poor prognosis. Most patients are diagnosed at an advanced stage due to the lack of specific presentation in the early stages. Exosomes are a class of extracellular vesicles (EVs) widely found in body fluids and can release genetic material or multiple proteins to facilitate intercellular communication. In recent years, exosomal miRNAs have gained attention for their role in various cancers. These exosomal miRNAs can impact GC development and progression by targeting specific genes or influencing signaling pathways and cytokines involved in Angiogenesis, epithelial-mesenchymal transition (EMT), drug resistance, and immune regulation. They show great potential in terms of diagnosis, prognosis, and treatment of GC. Notably, the gastrointestinal tract has the largest number of macrophages, which play a significant role in GC progression. Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and can influence macrophage programming through various mediators, including macrophage polarization. Macrophage polarization is involved in inflammatory responses and significantly impacts the GC process.

Continued attention: The role of exosomal long non-coding RNAs in tumors over the past three years

This review summarizes the research on exosomal lncRNAs in tumors over the past three years. It highlights the significant roles of exosomal lncRNAs in modulating various cellular processes within the tumor microenvironment. Exosomal lncRNAs have been shown to influence the behavior of tumor cells, promoting proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, glycolysis, and contributing to tumor growth and metabolism. Moreover, exosomal lncRNAs have been found to interact with immune cells, such as modulating the functions of macrophages and influencing the overall immune response against tumors. Fibroblasts within the tumor microenvironment are also affected by exosomal lncRNAs, which can alter the extracellular matrix (ECM) and stromal composition. Notably, these exosomal lncRNAs hold promise in the diagnosis and treatment of tumors, offering potential biomarkers and therapeutic targets for improved clinical outcomes.

Gastric cancer-derived exosomal let-7 g-5p mediated by SERPINE1 promotes macrophage M2 polarization and gastric cancer progression

BACKGROUND

Tumor-associated macrophages (TAMs), particularly M2-polarized TAMs, are significant contributors to tumor progression, immune evasion, and therapy resistance in gastric cancer (GC). Despite efforts to target TAM recruitment or depletion, clinical efficacy remains limited. Consequently, the identification of targets that specifically inhibit or reprogram M2-polarized TAMs presents a promising therapeutic strategy.

OBJECTIVE

This study aims to identify a dual-function target in GC cells that drives both malignant phenotypes and M2 macrophage polarization, revealing its molecular mechanisms to provide novel therapeutic targets for selectivly targeting M2-polarized TAMs in GC.

METHODS

Transcriptomic and clinical data from GC and adjacent tissues were utilized to identify mRNAs associated with high M2 macrophage infiltration and poor prognosis. Single-cell sequencing elucidated cell types expressing the target gene. Transwell co-culture and exosome intervention experiments demonstrated its role in M2 polarization. Small RNA sequencing of exosomes, western blotting, and CoIP assays revealed the molecular mechanisms underlying exosome-mediated M2 polarization. Protein array, ChIP and dual-luciferase reporter assays clarified the molecular mechanisms by which the target gene regulated exosomal miRNA. In vivo validation was performed using xenograft tumor models.

RESULTS

SERPINE1 was identified as a highly expressed mRNA in GC tissues and cells, significantly associated with advanced clinical stages, worse prognosis, and higher M2 macrophage infiltration in patients with GC. SERPINE1 overexpression in GC cells promoted tumor growth and M2 macrophage polarization. SERPINE1 facilitated the transfer of let-7 g-5p to macrophages via cancer-derived exosomes, inducing M2 polarization. Exosomal let-7 g-5p internalized by macrophages downregulated SOCS7 protein levels, disrupting its interaction with STAT3 and relieving the inhibition of STAT3 phosphorylation, thereby leading to STAT3 hyperactivation, which consequently drove M2 polarization. Additionally, in GC cells, elevated SERPINE1 expression activated JAK2, enhancing STAT3 binding to the let-7 g-5p promoter and promoting its transcription, thereby increasing let-7 g-5p levels in exosomes.

CONCLUSION

GC cell-derived SERPINE1, functioning as a primary driver of GC growth and TAM M2 polarization, promotes M2 polarization through the regulation of exosomal let-7 g-5p transfer via autocrine activation of the JAK2/STAT3 signaling pathway. These findings elucidate a novel mechanism of SERPINE1-induced M2 polarization and highlight SERPINE1 as a promising target for advancing immunotherapy and targeted treatments in GC.

Extracellular vesicles from chronic lymphocytic leukemia cells promote leukemia aggressiveness by inducing the differentiation of monocytes into nurse-like cells via an RNA-dependent mechanism

Chronic lymphocytic leukemia (CLL) cells receive several stimuli from surrounding cells, such as B-cell receptor (BCR) stimulation, and can manipulate their microenvironment via extracellular vesicle (EV) release. Here, we investigated the small RNA content (microRNA and YRNA) of CLL-EVs from leukemic cells cultured with/without BCR stimulation. We highlight an increase of miR-155-5p, miR-146a-5p, and miR-132-3p in EVs and in cells after BCR stimulation (p < 0.05, n = 25). CLL-EVs were preferentially internalized by monocytes (p = 0.0019, n = 6) and able to deliver microRNAs and the hY4 RNA. Furthermore, BCR CLL-EV induced modifications in monocytes (shape change, microRNA and gene expression, secretome) suggesting nurse-like cell (NLC) differentiation, the tumor-associated macrophages of CLL. Functionally, monocytes treated with BCR CLL-EVs protect CLL cells from spontaneous apoptosis by pro-survival cytokine production and induce their migration as well as the migration of other immune cells. We finally reported by transfection experiments that hY4 is able to induce the expression of CCL24, a key gene in M2 macrophage differentiation. In conclusion, we showed that BCR stimulation modifies the small RNA content of CLL-EVs and that the addition of leukemic EVs to monocytes leads to monocyte differentiation into NLCs establishing a protective microenvironment that supports leukemic cell survival.

Examination of the effects of capecitabine treatment on the HT-29 colorectal cancer cell line and HCG 11, HCG 15, and HCG 18 lncRNAs in CRC patients before and after chemotherapy

Colorectal cancer (CRC) is the third most common malignancy worldwide. Long noncoding RNAs (lncRNAs) are involved in several pathogenic pathways related to CRC. This study aimed to compare the expression profiles of HCG11, HCG15, and HCG18 genes in CRC patients before and after chemotherapy. Moreover, capecitabine's effects, which is a chemotherapeutic agent, were investigated on apoptosis, cell cycle, and the lncRNA expression in CRC using HT-29 cells. qRT-PCR was used to measure lncRNAs expression in patient and healthy tissues, and the HT-29 CRC cell line. Additionally, the diagnostic and prognostic utility of these lncRNAs were assessed using the ROC curve analysis. The MTT assay was used to evaluate the cytotoxicity of capecitabine, and by using flow cytometry, apoptosis induction and cell cycle progression were investigated. CRC patients expressed higher levels of HCG11 and HCG15 and lower levels of HCG18. Furthermore, those receiving capecitabine demonstrated a decrease in HCG11 and an increase in HCG18 expression. In the HT-29 cell line, capecitabine can also increase the expression of HCG18 and decrease the expression of HCG11 and HCG15. However, no statistically significant variations were determined in the expression of these lncRNAs in clinical variables. Additionally, the data show that HCG18 is a poor prognostic biomarker, and HCG11 and HCG18 are poor diagnostic biomarkers. Treatment with capecitabine caused an accumulation of sub-G1 cells, indicating a potent apoptotic effect on HT-29 cells. These findings confirmed capecitabine's anticancer effects and showed that it can increase HCG18 and reduce HCG11 and HCG15 expression.

LncRNA HCG18 affects aortic dissection through the miR-103a-3p/HMGA2 axis by modulating proliferation and apoptosis of vascular smoothing muscle cells

BACKGROUND

Aortic Dissection (AD) is a vascular disease with a high mortality rate and limited treatment strategies. The current research analyzed the function and regulatory mechanism of lncRNA HCG18 in AD.

METHODS

HCG18, miR-103a-3p, and HMGA2 levels in the aortic tissue of AD patients were examined by RT-qPCR. After transfection with relevant plasmids, the proliferation of rat aortic Vascular Smoothing Muscle Cells (VSMCs) was detected by CCK-8 and colony formation assay, Bcl-2 and Bax was measured by Western blot, and apoptosis was checked by flow cytometry. Then, the targeting relationship between miR-103a-3p and HCG18 or HMGA2 was verified by bioinformation website analysis and dual luciferase reporter assay. Finally, the effect of HCG18 was verified in an AD rat model induced by β-aminopropionitrile.

RESULTS

HCG18 and HMGA2 were upregulated and miR-103a-3p was downregulated in the aortic tissues of AD patients. Downregulating HCG18 or upregulating miR-103a-3p enhanced the proliferation of VSMCs and limited cell apoptosis. HCG18 promoted HMGA2 expression by competing with miR-103a-3p and restoring HMGA2 could impair the effect of HCG18 downregulation or miR-103a-3p upregulation in mediating the proliferation and apoptosis of VSMCs. In addition, down-regulation of HCG18 could improve the pathological injury of the aorta in AD rats.

CONCLUSION

HCG18 reduces proliferation and induces apoptosis of VSMCs through the miR-103a-3p/HMGA2 axis, thus aggravating AD.

Macrophage biology in the pathogenesis of Helicobacter pylori infection

Infection with H. pylori induces chronic gastric inflammation, progressing to peptic ulcer and stomach adenocarcinoma. Macrophages function as innate immune cells and play a vital role in host immune defense against bacterial infection. However, the distinctive mechanism by which H. pylori evades phagocytosis allows it to colonize the stomach and further aggravate gastric preneoplastic pathology. H. pylori exacerbates gastric inflammation by promoting oxidative stress, resisting macrophage phagocytosis, and inducing M1 macrophage polarization. M2 macrophages facilitate the proliferation, invasion, and migration of gastric cancer cells. Various molecular mechanisms governing macrophage function in the pathogenesis of H. pylori infection have been identified. In this review, we summarize recent findings of macrophage interactions with H. pylori infection, with an emphasis on the regulatory mechanisms that determine the clinical outcome of bacterial infection.

TREM1 facilitates the development of gastric cancer through regulating neutrophil extracellular traps-mediated macrophage polarization

Triggering receptor expressed on myeloid cell 1 (TREM1) elevation is associated with the unfavorable prognosis of gastric cancer (GC) patients. This work uncovered the effects and mechanism of TREM1 in GC. IHC staining examined TREM1 expression in GC tissues. TREM1-knockout and TREM1 knock-in mice were generated prior to the construction of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced GC mice model. H&E staining detected the pathological alternations of gastric tissues. IHC staining tested Ki67 expression. Wright-Giemsa staining performed neutrophil counting and flow cytometry analysis measured neutrophil infiltration. ELISA analyzed serum and tissue myeloperoxidase (MPO) levels and serum MPO-DNA levels. Immunofluorescence, Western blotting and related kits detected NETs formation. Immunofluorescence and IHC staining evaluated macrophage polarization. In MNNG-treated GES-1 cells and phorbal myristate acetate (PMA)-treated neutrophils, TREM1 expression was also examined. CCK-8 method and Western blotting assayed cell proliferation. Western blotting and immunofluorescence detected NETs formation. Flow cytometry analysis detected the changes of macrophage typing. TREM1 was overexpressed in tumor tissues, MNNG-treated GES-1 cells and PMA-treated neutrophils. TREM1 deficiency hindered tumor growth, reduced neutrophil infiltration, NETs formation and stimulated M1 macrophage polarization in MNNG-induced GC models. Neutrophil extracellular traps (NETs) degrader DNase-1 countervailed the impacts of TREM1 on MNNG-induced GC models in vivo. Collectively, TREM1 knockdown obstructed NETs-mediated M2 macrophage polarization to hamper GC progression.

Exosomal lncRNA USP30-AS1 activates the Wnt/β-catenin signaling pathway to promote cervical cancer progression via stabilization of β-catenin by USP30

Cervical cancer (CC) remains a major cause of cancer-related mortality among women globally. Long noncoding RNAs (lncRNAs) play crucial regulatory roles in various cancers, including CC. This study investigates the function of a novel lncRNA, USP30 antisense RNA 1 (USP30-AS1), in CC tumorigenesis. We analyzed USP30-AS1 expression using RT-qPCR and conducted in vitro loss-of-function assays, as well as in vivo assays, to evaluate the effects of USP30-AS1 silencing on CC cell growth and migration. Additional mechanistic experiments, including RNA pull-down, RNA immunoprecipitation (RIP), and co-immunoprecipitation (Co-IP) assays, were performed to elucidate the regulatory mechanisms influenced by USP30-AS1. We discovered that USP30-AS1 is overexpressed in CC tissues and cells. Silencing USP30-AS1 significantly reduced cell proliferation, migration, invasion, and tumor growth. Moreover, USP30-AS1 was found to modulate the expression of ubiquitin-specific peptidase 30 (USP30) by sponging microRNA-2467-3p (miR-2467-3p) and recruiting the FUS RNA binding protein (FUS), thereby stabilizing β-catenin and activating the Wnt/β-catenin signaling pathway. These findings suggest that USP30-AS1 enhances CC cell growth and migration through the miR-2467-3p/FUS/USP30 axis, highlighting its potential as a biomarker for CC.

LncRNAs act as modulators of macrophages within the tumor microenvironment

Long non-coding RNAs (lncRNAs) have been established as pivotal players in various cellular processes, encompassing the regulation of transcription, translation and post-translational modulation of proteins, thereby influencing cellular functions. Notably, lncRNAs exert a regulatory influence on diverse biological processes, particularly in the context of tumor development. Tumor-associated macrophages (TAMs) exhibit the M2 phenotype, exerting significant impact on crucial processes such as tumor initiation, angiogenesis, metastasis and immune evasion. Elevated infiltration of TAMs into the tumor microenvironment (TME) is closely associated with a poor prognosis in various cancers. LncRNAs within TAMs play a direct role in regulating cellular processes. Functioning as integral components of tumor-derived exosomes, lncRNAs prompt the M2-like polarization of macrophages. Concurrently, reports indicate that lncRNAs in tumor cells contribute to the expression and release of molecules that modulate TAMs within the TME. These actions of lncRNAs induce the recruitment, infiltration and M2 polarization of TAMs, thereby providing critical support for tumor development. In this review, we survey recent studies elucidating the impact of lncRNAs on macrophage recruitment, polarization and function across different types of cancers.

Extracellular vesicles mediated gastric cancer immune response: tumor cell death or immune escape?

Gastric cancer (GC) is a major global health issue, being the fifth most prevalent cancer and the third highest contributor to cancer-related deaths. Although treatment strategies for GC have diversified, the prognosis for advanced GC remains poor. Hence, there is a critical need to explore new directions for GC treatment to enhance diagnosis, treatment, and patient prognosis. Extracellular vesicles (EVs) have emerged as key players in tumor development and progression. Different sources of EVs carry different molecules, resulting in distinct biological functions. For instance, tumor-derived EVs can promote tumor cell proliferation, alter the tumor microenvironment and immune response, while EVs derived from immune cells carry molecules that regulate immune function and possess tumor-killing capabilities. Numerous studies have demonstrated the crucial role of EVs in the development, immune escape, and immune microenvironment remodeling in GC. In this review, we discuss the role of GC-derived EVs in immune microenvironment remodeling and EVs derived from immune cells in GC development. Furthermore, we provide an overview of the potential uses of EVs in immunotherapy for GC.

Exosomal circPOLQ promotes macrophage M2 polarization via activating IL-10/STAT3 axis in a colorectal cancer model

BACKGROUND

Accumulating evidence demonstrates that an increased tumor-associated macrophage abundance is often associated with poor prognosis in colorectal cancer (CRC). The mechanism underlying the effect of tumor-derived exosomes on M2 macrophage polarization remains elusive.

RESULTS

The novel circular RNA circPOLQ exhibited significantly higher expression in CRC tissues than in paired normal tissues. Higher circPOLQ expression was associated with poorer prognosis in patients with CRC. In vitro and in vivo experiments showed that tumor-derived exosomal circPOLQ did not directly regulate CRC cell development but promoted CRC metastatic nodule formation by enhancing M2 macrophage polarization. circPOLQ activated the interleukin-10/signal transducer and activator of transcription 3 axis by targeting miR-379-3 p to promote M2 macrophage polarization.

CONCLUSION

circPOLQ can enter macrophages via CRC cell-derived exosomes and promote CRC metastatic nodule formation by enhancing M2 macrophage polarization. These findings reveal a tumor-derived exosome-mediated tumor-macrophage interaction potentially affecting CRC metastatic nodule formation.

The hidden messengers: cancer associated fibroblasts-derived exosomal miRNAs as key regulators of cancer malignancy

Cancer-associated fibroblasts (CAFs), a class of stromal cells in the tumor microenvironment (TME), play a key role in controlling cancer cell invasion and metastasis, immune evasion, angiogenesis, and resistance to chemotherapy. CAFs mediate their activities by secreting soluble chemicals, releasing exosomes, and altering the extracellular matrix (ECM). Exosomes contain various biomolecules, such as nucleic acids, lipids, and proteins. microRNA (miRNA), a 22-26 nucleotide non-coding RNA, can regulate the cellular transcription processes. Studies have shown that miRNA-loaded exosomes secreted by CAFs engage in various regulatory communication networks with other TME constituents. This study focused on the roles of CAF-derived exosomal miRNAs in generating cancer malignant characteristics, including immune modulation, tumor growth, migration and invasion, epithelial-mesenchymal transition (EMT), and treatment resistance. This study thoroughly examines miRNA's dual regulatory roles in promoting and suppressing cancer. Thus, changes in the CAF-derived exosomal miRNAs can be used as biomarkers for the diagnosis and prognosis of patients, and their specificity can be used to develop newer therapies. This review also discusses the pressing problems that require immediate attention, aiming to inspire researchers to explore more novel avenues in this field.

Identification and analysis of MSC-Exo-derived LncRNAs related to the regulation of EMT in hypospadias

OBJECTIVE

This study aims to screen the differentially expressed long non-coding RNAs (DELncRNAs) related to the regulation of epithelial-mesenchymal transition (EMT) in hypospadias in mesenchymal stem cell-derived exosomes (MSC-Exons) and explore the potential mechanism of these lncRNAs for the EMT in hypospadias.

METHODS

In this study, the microarray data related to MSC-Exos and hypospadias were downloaded from Gene Expression Omnibus (GEO). Besides, the lncRNAs highly expressed in MSC-Exos and the differentially expressed mRNAs and lncRNAs in children with hypospadias were screened, respectively. In addition, the lncRNAs enriched in MSC-Exos and differentially expressed lncRNAs in hypospadias were intersected to obtain the final DElncRNAs. Moreover, the co-expression interaction pairs of differentially expressed lncRNAs and mRNAs were analyzed to construct a Competing Endogenous RNA (ceRNA) network. Finally, the candidate lncRNAs in exosomes were subjected to in vitro cell function verification.

RESULTS

In this study, a total of 4 lncRNAs were obtained from the microarray data analysis. Further, a ceRNA regulatory network of MSC-Exo-derived lncRNAs related to the regulation of EMT in hypospadias was constructed, including 4 lncRNAs, 2 mRNAs, and 6 miRNAs. The cell function verification results indicated that the exosomes secreted by MSCs may transport HLA complex group 18 (HCG18) into target cells, which promoted the proliferation, migration, and EMT of these cells.

CONCLUSION

MSC-Exo-derived lncRNA HCG18 can enter target cells, and it may be involved in the regulation of EMT in hypospadias through the ceRNA network.

The rising roles of exosomes in the tumor microenvironment reprogramming and cancer immunotherapy

Exosomes are indispensable for intercellular communications. Tumor microenvironment (TME) is the living environment of tumor cells, which is composed of various components, including immune cells. Based on TME, immunotherapy has been recently developed for eradicating cancer cells by reactivating antitumor effect of immune cells. The communications between tumor cells and TME are crucial for tumor development, metastasis, and drug resistance. Exosomes play an important role in mediating these communications and regulating the reprogramming of TME, which affects the sensitivity of immunotherapy. Therefore, it is imperative to investigate the role of exosomes in TME reprogramming and the impact of exosomes on immunotherapy. Here, we review the communication role of exosomes in regulating TME remodeling and the efficacy of immunotherapy, as well as summarize the underlying mechanisms. Furthermore, we also introduce the potential application of the artificially modified exosomes as the delivery systems of antitumor drugs. Further efforts in this field will provide new insights on the roles of exosomes in intercellular communications of TME and cancer progression, thus helping us to uncover effective strategies for cancer treatment.

The role of lncRNA HCG18 in human diseases

A substantial number of long noncoding RNAs (lncRNAs) have been identified as potent regulators of human disease. Human leukocyte antigen complex group 18 (HCG18) is a new type of lncRNA that has recently been proven to play an important role in the occurrence and development of various diseases. Studies have found that abnormal expression of HCG18 is closely related to the clinicopathological characteristics of many diseases. More importantly, HCG18 was also found to promote disease progression by affecting a series of cell biological processes. This article mainly discusses the expression characteristics, clinical characteristics, biological effects and related regulatory mechanisms of HCG18 in different human diseases, providing a scientific theoretical basis for its early clinical application.

Exosome-mediated communication between gastric cancer cells and macrophages: implications for tumor microenvironment

Gastric cancer (GC) is a malignant neoplasm originating from the epithelial cells of the gastric mucosa. The pathogenesis of GC is intricately linked to the tumor microenvironment within which the cancer cells reside. Tumor-associated macrophages (TAMs) primarily differentiate from peripheral blood monocytes and can be broadly categorized into M1 and M2 subtypes. M2-type TAMs have been shown to promote tumor growth, tissue remodeling, and angiogenesis. Furthermore, they can actively suppress acquired immunity, leading to a poorer prognosis and reduced tolerance to chemotherapy. Exosomes, which contain a myriad of biologically active molecules including lipids, proteins, mRNA, and noncoding RNAs, have emerged as key mediators of communication between tumor cells and TAMs. The exchange of these molecules via exosomes can markedly influence the tumor microenvironment and consequently impact tumor progression. Recent studies have elucidated a correlation between TAMs and various clinicopathological parameters of GC, such as tumor size, differentiation, infiltration depth, lymph node metastasis, and TNM staging, highlighting the pivotal role of TAMs in GC development and metastasis. In this review, we aim to comprehensively examine the bidirectional communication between GC cells and TAMs, the implications of alterations in the tumor microenvironment on immune escape, invasion, and metastasis in GC, targeted therapeutic approaches for GC, and the efficacy of potential GC drug resistance strategies.

Tumor-Derived Exosomal LINC01480 Upregulates VCAM1 Expression by Acting as a Competitive Endogenous RNA of miR-204-5p to Promote Gastric Cancer Progression

Exosomes are a type of cell-derived vesicles that range in size from 30 to 100 nm. They are widely present in various organisms and participate in diverse biological processes, playing crucial roles in tumorigenesis and progression. This study aimed to investigate whether LINC01480 in tumor-derived exosomes is involved in the molecular mechanism of gastric cancer by competitively upregulating the VCAM1 expression through binding miR-204-5p. The study analyzed transcriptome data related to gastric cancer from the cancer genome atlas database and constructed a risk-scoring model for epithelial-mesenchymal transition (EMT)-related lncRNAs to identify eight EMT-related lncRNAs associated with prognosis. EMT-related mRNAs positively correlated with LINC01480 were screened in the ExoRBase database. In vitro cell experiments showed that exosomal LINC01480 can promote the proliferation, migration, invasion, and EMT of gastric cancer cells by upregulating VCAM1 expression through competitive binding with miR-204-5p. In vivo experiments on nude mice showed that exosomal LINC01480 promotes the development of gastric cancer. These results suggest that exosomal LINC01480 could be a potential therapeutic target for gastric cancer.

lncRNA BANCR promotes the colorectal cancer metastasis through accelerating exosomes-mediated M2 macrophage polarization via regulating RhoA/ROCK signaling

Cancer cells-derived exosomal lncRNAs could modulate the tumorigenesis of colorectal cancer (CRC) via modulating macrophage M2 polarization. However, the clarified mechanism and function of lncRNA BANCR in CRC remains unclear. Exosomes were identified by TEM, NTA, western blot and fluorescent staining. M2 macrophages were identified by CD206 and CD163 expressions using by flow cytometry and RT-qPCR. In addition, the relation between IGF2BP2 and BANCR or RhoA were explored by RIP assay. The malignant behaviors of CRC cells were examined by CCK-8, EdU and transwell assays. Histopathological changes in mice were observed by H&E staining. Silencing of BANCR notably inhibited the proliferation, migration and invasion of CRC cells. SW620 and HCT-15 cells-derived exosomal BANCR positively regulated the macrophage M2 polarization. In addition, exosomal BANCR remarkably enhanced the promoting roles mediated by M2 macrophages on proliferation and invasion in CRC cells. Meanwhile, exosomal BANCR promoted the M2 macrophage polarization via activation of RhoA/Rock pathway by recruiting IGF2BP2. Inhibition of RhoA/Rock pathway reversed exosomal BANCR-mediated macrophages M2 polarization and CRC malignant behaviors in SW620 and HCT-15 cells. Exosomal lncRNA BANCR derived from SW620 and HCT-15 cells promoted the metastasis of CRC via inducing the polarization of M2 macrophages. Thus, BANCR might be a new target for the treatment of CRC.

The diverse effects of cisplatin on tumor microenvironment: Insights and challenges for the delivery of cisplatin by nanoparticles

Cisplatin is a well-known platinum-based chemotherapy medication that is widely utilized for some malignancies. Despite the direct cytotoxic consequences of cisplatin on tumor cells, studies in the recent decade have revealed that cisplatin can also affect different cells and their secretions in the tumor microenvironment (TME). Cisplatin has complex impacts on the TME, which may contribute to its anti-tumor activity or drug resistance mechanisms. These regulatory effects of cisplatin play a paramount function in tumor growth, invasion, and metastasis. This paper aims to review the diverse impacts of cisplatin and nanoparticles loaded with cisplatin on cancer cells and also non-cancerous cells in TME. The impacts of cisplatin on immune cells, tumor stroma, cancer cells, and also hypoxia will be discussed in the current review. Furthermore, we emphasize the challenges and prospects of using cisplatin in combination with other adjuvants and therapeutic modalities that target TME. We also discuss the potential synergistic effects of cisplatin with immune checkpoint inhibitors (ICIs) and other agents with anticancer potentials such as polyphenols and photosensitizers. Furthermore, the potential of nanoparticles for targeting TME and better delivery of cisplatin into tumors will be discussed.

Macrophage lncRNAs in cancer development: Long-awaited therapeutic targets

In the tumor microenvironment, the interplay among macrophages, cancer cells, and endothelial cells is multifaceted. Tumor-associated macrophages (TAMs), which often exhibit an M2 phenotype, contribute to tumor growth and angiogenesis, while cancer cells and endothelial cells reciprocally influence macrophage behavior. This complex interrelationship highlights the importance of targeting these interactions for the development of novel cancer therapies aimed at disrupting tumor progression and angiogenesis. Accumulating evidence underscores the indispensable involvement of lncRNAs in shaping macrophage functionality and contributing to the development of cancer. Animal studies have further validated the therapeutic potential of manipulating macrophage lncRNA activity to ameliorate disease severity and reduce morbidity rates. This review provides a survey of our current understanding of macrophage-associated lncRNAs, with a specific emphasis on their molecular targets and their regulatory impact on cancer progression. These lncRNAs predominantly govern macrophage polarization, favoring the dominance of M2 macrophages or TAMs. Exosomes or extracellular vesicles mediate lncRNA transfer between macrophages and cancer cells, affecting cellular functions of each other. Moreover, this review presents therapeutic strategies targeting cancer-associated lncRNAs. The insights and findings presented in this review pertaining to macrophage lncRNAs can offer valuable information for the development of treatments against cancer.

Tumor-derived exosomal linc00881 induces lung fibroblast activation and promotes osteosarcoma lung migration

Osteosarcoma (OS) commonly metastasizes to the lung, yet the underlying molecular mechanisms remain poorly understood. Exosomes play a crucial role in tumor migration, including OS lung migration. However, the underlying mechanism by which exosome-derived long non-coding RNAs (lncRNAs) contribute to lung migration in osteosarcoma (OS) remains unclear. This study presents a newly discovered lncRNA, linc00881, derived from OS exosomes. Our study shows that linc00881 promotes the migration of OS cells to the lung and induces the conversion of normal lung fibroblasts into cancer-associated fibroblasts (CAFs). Subsequently, we found that exosomal linc00881 secreted by OS cells can regulate the expression of matrix metalloproteinase 2 (MMP2) in HFL-1 cells by sponging miR-29c-3p, thereby activating the NF-κB signaling in lung fibroblasts. Finally, we discovered that pro-inflammatory cytokines, namely IL-1β, IL-6, and IL-8, were secreted through the linc00881/miR-29c-3p/MMP2 axis. These results suggest that OS-derived exosomes can mediate the intercellular crosstalk between OS cells and lung fibroblasts, ultimately impacting OS lung migration. Our study provides a potential target for the treatment of OS lung migration.

Unveiling the functional paradigm of exosome-derived long non-coding RNAs (lncRNAs) in cancer: based on a narrative review and systematic review

BACKGROUND AND PURPOSE

The intricate mechanisms underlying intercellular communication within the tumor microenvironment remain largely elusive. Recently, attention has shifted towards exploring the intercellular signaling mediated by exosomal long non-coding RNAs (lncRNAs) within this context. This comprehensive systematic review aims to elucidate the functional paradigm of exosome-derived lncRNAs in cancer.

MATERIALS AND METHODS

The review provides a comprehensive narrative of lncRNA definition, characteristics, as well as the formation, sorting, and uptake processes of exosome-derived lncRNAs. Additionally, it describes comprehensive technology for exosome research and nucleic acid drug loading. This review further systematically examines the cellular origins, functional roles, and underlying mechanisms of exosome-derived lncRNAs in recipient cells within the cancer setting.

RESULTS

The functional paradigm of exosome-derived lncRNAs in cancer mainly depends on the source cells and sorting mechanism of exosomal lncRNAs, the recipient cells and uptake mechanisms of exosomal lncRNAs, and the specific molecular mechanisms of lncRNAs in recipient cells. The source cells of exosomal lncRNAs mainly involved in the current review included tumor cells, cancer stem cells, normal cells, macrophages, and cancer-associated fibroblasts.

CONCLUSION

This synthesis of knowledge offers valuable insights for accurately identifying exosomal lncRNAs with potential as tumor biomarkers. Moreover, it aids in the selection of appropriate targeting strategies and preclinical models, thereby facilitating the clinical translation of exosomal lncRNAs as promising therapeutic targets against cancer. Through a comprehensive understanding of the functional role of exosome-derived lncRNAs in cancer, this review paves the way for advancements in personalized medicine and improved treatment outcomes.

Tumor-derived exosome ElNF1-AS1 affects the progression of gastric cancer by promoting M2 polarization of macrophages

BACKGROUND

This study attempted to investigate the role of exosome ELFN1-AS1 in gastric cancer (GC).

METHODS

The study used various techniques to determine the level of exosomal ELFN1-AS1 in GC tissue and cells, including quantitative real-time PCR. Pull-down assay and dual-luciferase reporter assay were employed to identify interactions between ELFN1-AS1 and miR-4644, as well as miR-4644 and PKM. Western blot was employed to explore the potential regulatory mechanism. Several in vitro assays were conducted in xenograft models to investigate the impacts of exosomal ELFN1-AS1 on GC development, metastasis and macrophage polarization.

RESULTS

ELFN1-AS1 was upregulated in GC tissue and cells, with high enrichment in GC-derived exosomes. Exosomal ELFN1-AS1 enhances the cell abilities and stemness of GC. ELFN1-AS1 targeted and regulated miR-4644, which triggered PKM expression. Exosomal ELFN1-AS1 modulated glycolysis via PKM in an HIF-1α dependent manner in GC, promoting M2 polarization and macrophage recruitment. Furthermore, exosomal ELFN1-AS1 enhanced GC cell growth, metastasis and M2 polarization in vivo.

CONCLUSIONS

The study suggests that ELFN1-AS1 could be a promising biomarker for the diagnosis and treatment of GC.

Tumor cell-derived exosomes regulate macrophage polarization: Emerging directions in the study of tumor genesis and development

As an extracellular vesicle, exosomes play an important role in intercellular information transmission, delivering cargos of the parent cell, such as RNA, DNA, proteins, and lipids, activating different signaling pathways in the target cell and regulating inflammation, angiogenesis, and tumor progression. In particular, exosomes secreted by tumor cells can change the function of surrounding cells, creating a microenvironment conducive to tumor growth and metastasis. For example, after macrophages phagocytose exosomes and accept their cargos, they activate macrophage polarization-related signaling pathways and polarize macrophages into M1 or M2 types to exert antitumor or protumor functions. Currently, the study of exosomes affecting the polarization of macrophages has attracted increasing attention. Therefore, this paper reviews relevant studies in this field to better understand the mechanism of exosome-induced macrophage polarization and provide evidence for exploring novel targets for tumor therapy and new diagnostic markers in the future.

Extracellular vesicles in gastric cancer: role of exosomal lncRNA and microRNA as diagnostic and therapeutic targets

Extracellular vesicles (EVs), including exosomes, play a crucial role in intercellular communication and have emerged as important mediators in the development and progression of gastric cancer. This review discusses the current understanding of the role of EVs, particularly exosomal lncRNA and microRNA, in gastric cancer and their potential as diagnostic and therapeutic targets. Exosomes are small membrane-bound particles secreted by both cancer cells and stromal cells within the tumor microenvironment. They contain various ncRNA and biomolecules, which can be transferred to recipient cells to promote tumor growth and metastasis. In this review, we highlighted the importance of exosomal lncRNA and microRNA in gastric cancer. Exosomal lncRNAs have been shown to regulate gene expression by interacting with transcription factors or chromatin-modifying enzymes, which regulate gene expression by binding to target mRNAs. We also discuss the potential use of exosomal lncRNAs and microRNAs as diagnostic biomarkers for gastric cancer. Exosomes can be isolated from various bodily fluids, including blood, urine, and saliva. They contain specific molecules that reflect the molecular characteristics of the tumor, making them promising candidates for non-invasive diagnostic tests. Finally, the potential of targeting exosomal lncRNAs and microRNAs as a therapeutic strategy for gastric cancer were reviewed as wee. Inhibition of specific molecules within exosomes has been shown to suppress tumor growth and metastasis in preclinical models. In conclusion, this review article provides an overview of the current understanding of the role of exosomal lncRNA and microRNA in gastric cancer. We suggest that further research into these molecules could lead to new diagnostic tools and therapeutic strategies for this deadly disease.

Tumour-associated macrophages in gastric cancer: From function and mechanism to application

BACKGROUND

Gastric cancer (GC) is a malignant tumour, with high morbidity and mortality rates worldwide. The occurrence and development of GC is a complex process involving genetic changes in tumour cells and the influence of the surrounding tumour microenvironment (TME). Accumulative evidence shows that tumour-associated macrophages (TAMs) play a vital role in GC, acting as plentiful and active infiltrating inflammatory cells in the TME.

MAIN BODY

In this review, the different functions and mechanisms of TAMs in GC progression, including the conversion of phenotypic subtypes; promotion of tumour proliferation, invasion and migration; induction of chemoresistance; promotion of angiogenesis; modulation of immunosuppression; reprogramming of metabolism; and interaction with the microbial community are summarised. Although the role of TAMs in GC remains controversial in clinical settings, clarifying their significance in the treatment selection and prognostic prediction of GC could support optimising TAM-centred clinicaltherapy.

CONCLUSION

In summary, we reviewed the the phenotypic polarisation, function and molecular mechanism of TAMs and their potential applications in the treatment selection and prognostic prediction of GC.

Exosomal non-coding RNAs' role in immune regulation and potential therapeutic applications

Exosomes are now significant players in both healthy and unhealthy cell-to-cell communication. Exosomes can mediate immune activation or immunosuppression, which can influence the growth of tumors. Exosomes affect the immune responses to malignancies in various ways by interacting with tumor cells and the environment around them. Exosomes made by immune cells can control the growth, metastasis, and even chemosensitivity of tumor cells. In contrast, exosomes produced by cancer cells can encourage immune responses that support the tumor. Exosomes carry circular RNAs, long non-coding RNAs, and microRNAs (miRNAs), all involved in cell-to-cell communication. In this review, we focus on the most recent findings concerning the role of exosomal miRNAs, lncRNAs, and circRNAs in immune modulation and the potential therapeutic implications of these discoveries.

Abscopal Effect, Extracellular Vesicles and Their Immunotherapeutic Potential in Cancer Treatment

The communication between tumor cells and the microenvironment plays a fundamental role in the development, growth and further immune escape of the tumor. This communication is partially regulated by extracellular vesicles which can direct the behavior of surrounding cells. In recent years, it has been proposed that this feature could be applied as a potential treatment against cancer, since several studies have shown that tumors treated with radiotherapy can elicit a strong enough immune response to eliminate distant metastasis; this phenomenon is called the abscopal effect. The mechanism behind this effect may include the release of extracellular vesicles loaded with damage-associated molecular patterns and tumor-derived antigens which activates an antigen-specific immune response. This review will focus on the recent discoveries in cancer cell communications via extracellular vesicles and their implication in tumor development, as well as their potential use as an immunotherapeutic treatment against cancer.

Long non-coding RNAs and gastric cancer: An update of potential biomarkers and therapeutic applications

The frequent metastasis of gastric cancer (GC) complicates the cure and therefore the development of effective diagnostic and therapeutic approaches is urgently necessary. In recent years, lncRNA has emerged as a drug target in the treatment of GC, particularly in the areas of cancer immunity, cancer metabolism, and cancer metastasis. This has led to the demonstration of the importance of these RNAs as prognostic, diagnostic and therapeutic agents. In this review, we provide an overview of the biological activities of lncRNAs in GC development and update the latest pathological activities, prognostic and diagnostic strategies, and therapeutic options for GC-related lncRNAs.

Connection of Cancer Exosomal LncRNAs, Sponging miRNAs, and Exosomal Processing and Their Potential Modulation by Natural Products

Cancerous exosomes contain diverse biomolecules that regulate cancer progression. Modulating exosome biogenesis with clinical drugs has become an effective strategy for cancer therapy. Suppressing exosomal processing (assembly and secretion) may block exosomal function to reduce the proliferation of cancer cells. However, the information on natural products that modulate cancer exosomes lacks systemic organization, particularly for exosomal long noncoding RNAs (lncRNAs). There is a gap in the connection between exosomal lncRNAs and exosomal processing. This review introduces the database (LncTarD) to explore the potential of exosomal lncRNAs and their sponging miRNAs. The names of sponging miRNAs were transferred to the database (miRDB) for the target prediction of exosomal processing genes. Moreover, the impacts of lncRNAs, sponging miRNAs, and exosomal processing on the tumor microenvironment (TME) and natural-product-modulating anticancer effects were then retrieved and organized. This review sheds light on the functions of exosomal lncRNAs, sponging miRNAs, and exosomal processing in anticancer processes. It also provides future directions for the application of natural products when regulating cancerous exosomal lncRNAs.

The Potential Use of Exosomes in Anti-Cancer Effect Induced by Polarized Macrophages

The rapid development of aberrant cells outgrowing their normal bounds, which can subsequently infect other body parts and spread to other organs-a process known as metastasis-is one of the significant characteristics of cancer. The main reason why cancer patients die is because of widespread metastases. This abnormal cell proliferation varies in cancers of over a hundred types, and their response to treatment can vary substantially. Several anti-cancer drugs have been discovered to treat various tumors, yet they still have harmful side-effects. Finding novel, highly efficient targeted therapies based on modifications in the molecular biology of tumor cells is essential to reduce the indiscriminate destruction of healthy cells. Exosomes, an extracellular vesicle, are promising as a drug carrier for cancer therapy due to their good tolerance in the body. In addition, the tumor microenvironment is a potential target to regulate in cancer treatment. Therefore, macrophages are polarized toward M1 and M2 phenotypes, which are involved in cancer proliferation and are malignant. It is evident from recent studies that controlled macrophage polarization might contribute to cancer treatment, by the direct way of using miRNA. This review provides an insight into the potential use of exosomes to develop an 'indirect', more natural, and harmless cancer treatment through regulating macrophage polarization.

The regulatory role of LncRNA HCG18 in various cancers

As a member of long non-coding RNAs (lncRNAs), LncRNA HLA complex group 18 (HCG18) has recently become the focus of cancer research. As outlined in this review, LncRNA HCG18 has been reported to be dysregulated in various cancers development and appears to be activated in a variety of tumors, including clear cell renal cell carcinoma (ccRCC), colorectal cancer (CRC), gastric cancer (GC), hepatocellular carcinoma (HCC), laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC), lung adenocarcinoma (LUAD), nasopharyngeal cancer (NPC), osteosarcoma (OS), and prostate cancer (PCa). Furthermore, the expression of lncRNA HCG18 decreased in bladder cancer (BC) and papillary thyroid cancer (PTC). Overall, the presence of these differential expressions suggests the clinical value of HCG18 in cancer therapy. Additionally, lncRNA HCG18 influences various biological processes of cancer cells. This review summarizes the molecular mechanisms of HCG18 in cancer development, highlights reported the abnormal expression of HCG18 found in various cancer types, and aims to discuss the potential of HCG18 as a target for cancer therapy.

The role of long non-coding RNA HCG18 in cancer

The incidence of cancer is increasing worldwide and is becoming the most common cause of death. Identifying new biomarkers for cancer diagnosis and prognosis is important for developing cancer treatment strategies and reducing mortality. Long non-coding RNAs (lncRNAs) are non-coding, single-stranded RNAs that play an important role as oncogenes or tumor suppressors in the occurrence and development of human tumors. Abnormal expression of human leukocyte antigen complex group 18 (HCG18) is observed in many types of cancer, and its imbalance is closely related to cancer progression. HCG18 regulates cell proliferation, invasion, metastasis, and anti-apoptosis through a variety of mechanisms. Therefore, HCG18 is a potential tumor biomarker and therapeutic target. However, the therapeutic significance of HCG18 has not been well studied, and future research may develop new intervention strategies to combat cancer. In this study, we reviewed the biological function, mechanism, and potential clinical significance of HCG18 in various cancers to provide a reference for future research.

Exosomal miRNAs-mediated macrophage polarization and its potential clinical application

Macrophages are highly heterogeneous and plastic immune cells that play an important role in the fight against pathogenic microorganisms and tumor cells. After different stimuli, macrophages can polarize to the M1 phenotype to show a pro-inflammatory effect and the M2 phenotype to show an anti-inflammatory effect. The balance of macrophage polarization is highly correlated with disease progression, and therapeutic approaches to reprogram macrophages by targeting macrophage polarization are feasible. There are a large number of exosomes in tissue cells, which can transmit information between cells. In particular, microRNAs (miRNAs) in the exosomes can regulate the polarization of macrophages and further affect the progression of various diseases. At the same time, exosomes are also effective "drug" carriers, laying the foundation for the clinical application of exosomes. This review describes some pathways involved in M1/M2 macrophage polarization and the effects of miRNA carried by exosomes from different sources on the polarization of macrophages. Finally, the application prospects and challenges of exosomes/exosomal miRNAs in clinical treatment are also discussed.

Exosomal miR-181a-5p derived from SAOS-2 cells promotes macrophages M2 polarization by targeting RORA

Although the interaction between tumor cells and tumor-associated macrophages (TAMs) has been widely studied; however, the mechanism of osteosarcoma cells in regulating the polarization of TAMs remains unclear. Exosomes from SAOS-2 cells were isolated and validated by electron microscopy and Western blot. Transfection of indicated plasmids was applied to modify the expressions of miR-181a-5p and RAR-related orphan receptor alpha (RORA). Flow cytometric analysis was carried out to analyze M1/M2 macrophage polarization. Quantitative real-time PCR was performed to determine the levels of miR-181a-5p and RORA. Protein levels of CD63, CD81, RORA, CD163, CD206, IL-10, CXCL10, and IL-1β were evaluated by Western blot. The direct interaction of miR-181a-5p and RORA was validated by dual-luciferase activity assay. The expression of miR-181a-5p was upregulated in osteosarcoma tissues and presented in SAOS-2-derived exosomes. SAOS-2-derived exosomes promoted the polarization of M2 macrophages by transferring miR-181a-5p. In addition, RORA was downregulated in osteosarcoma tissues and showed a negative correlation with miR-181a-5p. RORA was found to be the downstream target of miR-181a-5p in SAOS-2 cells. Inhibition of RORA reversed the effects of miR-181a-5p knockdown on the polarization of M2 macrophages. The results showed that exosomal miR-181a-5p derived from osteosarcoma cells induced polarization of M2 macrophages via targeting RORA.

LncRNA HCG18 loaded by polymorphonuclear neutrophil-secreted exosomes aggravates sepsis acute lung injury by regulating macrophage polarization

Polymorphonuclear neutrophils (PMNs) exert significant roles in septic acute lung injury (ALI). Accumulating evidence suggests that PMN-derived exosomes (PMN-exo) are a novel subcellular entity that is the fundamental link between PMN-driven inflammation and tissue damage. However, the role of PMN-exo in septic ALI and the underlying mechanisms remain unclear. Tumor necrosis factor-α (TNF-α), a key regulator of innate immunity in septic ALI, was used to induce PMN activation in vitro. Using an in vitro co-culture system, the rat alveolar macrophage cell line NR8383 was co-cultured with TNF-α-stimulated PMN-released exosomes (TNF-α-exo) to further confirm the results of the in vitro studies and explore the underlying mechanisms involved. A septic lung injury model was established by cecal ligation and puncture surgery, and PMN-exo were injected into septic mice through the tail vein, and then lung injury, inflammatory release, macrophage polarization, and apoptosis were examined. The results reported that TNF-α-exo promoted the activation of M1 macrophages after i.p. injection in vivo or co-culture in vitro. Furthermore, TNF-α-exo affected alveolar macrophage polarization by delivering HCG18. Mechanistic studies indicated that HCG18 mediated the function of TNF-α-exo by targeting IL-32 in macrophages. In addition, tail vein injection of si-HCG18 in septic mice significantly reduced TNF-α-exo-induced M1 macrophage activation and lung macrophage death, as well as histological lesions. In conclusion, TNF-α-exo-loaded HCG18 contributes to septic ALI by regulating macrophage polarization. These findings may provide new insights into novel mechanisms of PMN-macrophage polarization interactions in septic ALI and may provide new therapeutic strategies for patients with sepsis.

Crosstalk between extracellular vesicles and tumor-associated macrophage in the tumor microenvironment

In concert with hijacking key genes to drive tumor progression, cancer cells also have the unique ability to dynamically interact with host microenvironment and discreetly manipulate the surrounding stroma, also known as the tumor microenvironment (TME), to provide optimal conditions for tumor cells to thrive and evade host immunity. Complex cellular crosstalk and molecular signaling between cancer cells, surrounding non-malignant cells, and non-cellular components are involved in this process. While intercellular communication traditionally centers around chemokines, cytokines, inflammatory mediators, and growth factors, emerging pathways involving extracellular vesicles (EVs) are gaining increasing attention. The immunosuppressive TME is created and maintained in part by the large abundance of tumor-associated macrophages (TMAs), which are associated with drug resistance, poor prognosis, and have emerged as potential targets for cancer immunotherapy. TMAs are highly dynamic, and can be polarized into either M1 or M2-like macrophages. EVs are efficient cell-cell communication molecules that have been catapulted to the center of TMA polarization. In this article, we provide detailed examination of the determinative role of EVs in sustaining the TME through mediating crosstalk between tumor cells and tumor-associated macrophages.

Decoding Roles of Exosomal lncRNAs in Tumor-Immune Regulation and Therapeutic Potential

Exosomes are nanovesicles secreted into biofluids by various cell types and have been implicated in different physiological and pathological processes. Interestingly, a plethora of studies emphasized the mediating role of exosomes in the bidirectional communication between donor and recipient cells. Among the various cargoes of exosomes, long non-coding RNAs (lncRNAs) have been identified as crucial regulators between cancer cells and immune cells in the tumor microenvironment (TME) that can interfere with innate and adaptive immune responses to affect the therapeutic efficiency. Recently, a few major studies have focused on the exosomal lncRNA-mediated interaction between cancer cells and immune cells infiltrated into TME. Nevertheless, a dearth of studies pertains to the immune regulating role of exosomal lncRNAs in cancer and is still in the early stages. Comprehensive mechanisms of exosomal lncRNAs in tumor immunity are not well understood. Herein, we provide an overview of the immunomodulatory function of exosomal lncRNAs in cancer and treatment resistance. In addition, we also summarize the potential therapeutic strategies toward exosomal lncRNAs in TME.

Exosomal long non-coding RNAs: novel molecules in gastrointestinal cancers' progression and diagnosis

Gastrointestinal (GI) cancers arise in the GI tract and accessory organs, including the mouth, esophagus, stomach, liver, biliary tract, pancreas, small intestine, large intestine, and rectum. GI cancers are a major cause of cancer-related morbidity and mortality worldwide. Exosomes act as mediators of cell-to-cell communication, with pleiotropic activity in the regulation of homeostasis, and can be markers for diseases. Non-coding RNAs (ncRNAs), such as long non-coding RNAs (lncRNAs), can be transported by exosomes derived from tumor cells or non-tumor cells. They can be taken by recipient cells to alter their function or remodel the tumor microenvironment. Moreover, due to their uniquely low immunogenicity and excellent stability, exosomes can be used as natural carriers for therapeutic ncRNAs in vivo. Exosomal lncRNAs have a crucial role in regulating several cancer processes, including angiogenesis, proliferation, drug resistance, metastasis, and immunomodulation. Exosomal lncRNA levels frequently alter according to the onset and progression of cancer. Exosomal lncRNAs can therefore be employed as biomarkers for the diagnosis and prognosis of cancer. Exosomal lncRNAs can also monitor the patient's response to chemotherapy while also serving as potential targets for cancer treatment. Here, we discuss the role of exosomal lncRNAs in the biology and possible future treatment of GI cancer.

Tumor-derived extracellular vesicles modulate innate immune responses to affect tumor progression

Immune cells are capable of influencing tumor progression in the tumor microenvironment (TME). Meanwhile, one mechanism by which tumor modulate immune cells function is through extracellular vesicles (EVs), which are cell-derived extracellular membrane vesicles. EVs can act as mediators of intercellular communication and can deliver nucleic acids, proteins, lipids, and other signaling molecules between cells. In recent years, studies have found that EVs play a crucial role in the communication between tumor cells and immune cells. Innate immunity is the first-line response of the immune system against tumor progression. Therefore, tumor cell-derived EVs (TDEVs) which modulate the functional change of innate immune cells serve important functions in the context of tumor progression. Emerging evidence has shown that TDEVs dually enhance or suppress innate immunity through various pathways. This review aims to summarize the influence of TDEVs on macrophages, dendritic cells, neutrophils, and natural killer cells. We also summarize their further effects on the progression of tumors, which may provide new ideas for developing novel tumor therapies targeting EVs.

Tumor microenvironment-mediated immune tolerance in development and treatment of gastric cancer

Tumor microenvironment is the general term for all non-cancer components and their metabolites in tumor tissue. These components include the extracellular matrix, fibroblasts, immune cells, and endothelial cells. In the early stages of tumors, the tumor microenvironment has a tumor suppressor function. As the tumor progresses, tumor immune tolerance is induced under the action of various factors, such that the tumor suppressor microenvironment is continuously transformed into a tumor-promoting microenvironment, which promotes tumor immune escape. Eventually, tumor cells manifest the characteristics of malignant proliferation, invasion, metastasis, and drug resistance. In recent years, stress effects of the extracellular matrix, metabolic and phenotypic changes of innate immune cells (such as neutrophils, mast cells), and adaptive immune cells in the tumor microenvironment have been revealed to mediate the emerging mechanisms of immune tolerance, providing us with a large number of emerging therapeutic targets to relieve tumor immune tolerance. Gastric cancer is one of the most common digestive tract malignancies worldwide, whose mortality rate remains high. According to latest guidelines, the first-line chemotherapy of advanced gastric cancer is the traditional platinum and fluorouracil therapy, while immunotherapy for gastric cancer is extremely limited, including only Human epidermal growth factor receptor 2 (HER-2) and programmed death ligand 1 (PD-L1) targeted drugs, whose benefits are limited. Clinical experiments confirmed that cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), vascular endothelial growth factor receptor (VEGFR) and other targeted drugs alone or in combination with other drugs have limited efficacy in patients with advanced gastric cancer, far less than in lung cancer, colon cancer, and other tumors. The failure of immunotherapy is mainly related to the induction of immune tolerance in the tumor microenvironment of gastric cancer. Therefore, solving the immune tolerance of tumors is key to the success of gastric cancer immunotherapy. In this study, we summarize the latest mechanisms of various components of the tumor microenvironment in gastric cancer for inducing immune tolerance and promoting the formation of the malignant phenotype of gastric cancer, as well as the research progress of targeting the tumor microenvironment to overcome immune tolerance in the treatment of gastric cancer.

Tumor cell-derived exosomal lncRNA LOC441178 inhibits the tumorigenesis of esophageal carcinoma through suppressing macrophage M2 polarization

Esophageal carcinoma (EC) is a highly malignant type of tumor. In a previous study, the authors found that long non-coding RNA (lncRNA) LOC441178 inhibited the tumorigenesis of EC. Moreover, exosomes derived from tumor cells containing lncRNAs were found to play a key role in the tumor environment; however, whether exosomes can affect the tumor microenvironment by carrying LOC441178 remains unclear. Thus, the present study aimed to clarify this. In order to assess the effects of exosomal LOC441178 in EC, cell invasion and migration were examined using the Transwell assay. Exosomes were identified using transmission electron microscopy, Western blot analysis and nanoparticle tracking analysis. Furthermore, macrophage surface makers (CD206 and CD86) were analyzed using flow cytometry. Moreover, a subcutaneous xenograft mouse model was constructed to assess the role of TE-9 cells-derived exosomal LOC441178 in EC. The results revealed that LOC441178 overexpression notably suppressed the metastasis of EC cells. In addition, exosomes were successfully isolated from EC cells, and LOC441178 level was upregulated in exosomes derived from LOC441178- overexpressed EC cells. Exosomal LOC441178 also suppressed macrophage M2 polarization, and the polarized macrophages decreased EC cell invasion. Exosomes containing LOC441178 notably inhibited the growth of EC in mice. On the whole, the present study demonstrated that the delivery of LOC441178 by EC cell-secreted exosomes inhibited the tumorigenesis of EC by suppressing the polarization of M2 macrophages. These findings may provide a new theoretical basis for discovering new strategies against EC.

Exosomes in the tumor microenvironment: Promoting cancer progression

Exosomes, which are extracellular vesicles produced by endosomes, are important performers of intercellular communication functions. For more than three decades, there has been a growing awareness of exosomes as the contents of the tumor microenvironment and their intimate connection to the development of cancer. The composition, generation, and uptake of exosomes as well as their roles in tumor metastasis, angiogenesis, and immunosuppression are discussed in this paper. In order to stop the progression of cancer, it is crucial to find new diagnostic biomarkers and therapeutic targets for the disease. Knowing the biological characteristics of exosomes and their functions in tumor development helps in this endeavor.

Crosstalk among long non-coding RNA, tumor-associated macrophages and small extracellular vesicles in tumorigenesis and dissemination

Long noncoding RNAs (lncRNAs), which lack protein-coding ability, can regulate cancer cell growth, proliferation, invasion, and metastasis. Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment that have a significant impact on cancer progression. Small extracellular vesicles (sEV) are crucial mediators of intercellular communications. Cancer cell and macrophage-derived sEV can carry lncRNAs that influence the onset and progression of cancer. Dysregulation of lncRNAs, TAMs, and sEV is widely observed in tumors which makes them valuable targets for cancer immunotherapy. In this review, we summarize current updates on the interactions among sEV, lncRNAs, and TAMs in tumors and provide new perspectives on cancer diagnosis and treatment.

LncRNA-miRNA axis in tumor progression and therapy response: An emphasis on molecular interactions and therapeutic interventions

Epigenetic factors are critical regulators of biological and pathological mechanisms and they could interact with different molecular pathways. Targeting epigenetic factors has been an idea approach in disease therapy, especially cancer. Accumulating evidence has highlighted function of long non-coding RNAs (lncRNAs) as epigenetic factors in cancer initiation and development and has focused on their association with downstream targets. microRNAs (miRNAs) are the most well-known targets of lncRNAs and present review focuses on lncRNA-miRNA axis in malignancy and therapy resistance of tumors. LncRNA-miRNA regulates cell death mechanisms such as apoptosis and autophagy in cancers. This axis affects tumor metastasis via regulating EMT and MMPs. Besides, lncRNA-miRNA axis determines sensitivity of tumor cells to chemotherapy, radiotherapy and immunotherapy. Based on the studies, lncRNAs can be affected by drugs and genetic tools in cancer therapy and this may affect expression level of miRNAs as their downstream targets, leading to cancer suppression/progression. LncRNAs have both tumor-promoting and tumor-suppressor functions in cancer and this unique function of lncRNAs has complicated their implication in tumor therapy. LncRNA-miRNA axis can also affect other signaling networks in cancer such as PI3K/Akt, STAT3, Wnt/β-catenin and EZH2 among others. Notably, lncRNA/miRNA axis can be considered as a signature for diagnosis and prognosis in cancers.

Exosomal hsa_circ_0017252 attenuates the development of gastric cancer via inhibiting macrophage M2 polarization

Gastric cancer (GC) is an aggressive malignant tumor of the digestive system, with high morbidity rates. We previously demonstrated that miR-17-5p can modify tumorigenesis in GC. In addition, other studies have shown that circRNAs can regulate GC progression by sponging various miRNAs. However, the association between circRNAs and miR-17-5p in GC has not yet been explored. Hence, this study aimed to explore the possible interactions between various circRNAs and miR-17-5p using a dual-luciferase assay. CCK-8 was used to determine cell viability, and a Transwell assay was used to measure cell invasion and migration. Gene expression was assessed using quantitative reverse transcription PCR (RT-qPCR), and exosomes were identified using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Annexin V/PI staining was also used to detect cell apoptosis. These investigations collectively revealed that miR-17-5p is a target of the circRNA hsa_circ_0017252 and hsa_circ_0017252 is significantly downregulated in GC tissues. In addition, the overexpression of hsa_circ_0017252 inhibited GC cell migration by sponging of miR-17-5p, and GC cell-secreted exosomal hsa_circ_0017252 effectively inhibited macrophage M2-like polarization, which in turn suppressed GC cell invasion. Notably, exosomes containing hsa_circ_0017252 also suppressed GC tumor growth in vivo. Thus, our data suggest that the overexpression of hsa_circ_0017252 suppresses GC malignancy by sponging miR-17-5p. In addition, exosomal hsa_circ_0017252 excreted from GC cells attenuated GC progression by suppressing macrophage M2-like polarization. These findings improve our basic understanding of GC and open a novel avenue for developing more effective GC treatments.