M2 macrophages-derived exosomal microRNA-501-3p promotes the progression of lung cancer via targeting WD repeat domain 82

M2 macrophage-derived exosomes promote cell proliferation, migration and EMT of non-small cell lung cancer by secreting miR-155-5p

Tumor-associated macrophages (TAMs) are a type of highly plastic immune cells in the tumor microenvironment (TME), which can be classified into two main phenotypes: classical activated M1 macrophages and alternatively activated M2 macrophages. As previously reported, M2-polarized TAMs play critical role in promoting the progression of non-small cell lung cancer (NSCLC) via secreting exosomes, but the detailed mechanisms are still largely unknown. In the present study, the THP-1 monocytes were sequentially induced into M0 and M2-polarized macrophages, and the exosomes were obtained from M0 (M0-exos) and M2 (M2-exos) polarized macrophages, respectively, and co-cultured with NSCLC cells (H1299 and A549) to establish the exosomes-cell co-culture system in vitro. As it was determined by MTT assay, RT-qPCR and Transwell assay, in contrast with the M0-exos, M2-exos significantly promoted cell proliferation, migration and epithelial-mesenchymal transition (EMT) process in NSCLC cells. Next, through screening the contents in the exosomes, it was verified that miR-155-5p was especially enriched in the M2-exos, and M2-exos enhanced cancer aggressiveness and tumorigenesis in in vitro NSCLC cells and in vivo xenograft tumor-bearing mice models via delivering miR-155-5p. The detailed molecular mechanisms were subsequently elucidated, and it was found that miR-155-5p bound with HuR to increase the stability and expression levels of VEGFR2, which further activated the tumor-promoting PI3K/Akt/mTOR signal pathway, and M2-exos-enhanced cancer progression in NSCLC cells were apparently suppressed by downregulating VEGFR2 and PI3K inhibitor LY294002 co-treatment. Taken together, M2-polarized TAMs secreted miR-155-5p-containing exosomes to enhanced cancer aggressiveness of NSCLC by activating the VEGFR2/PI3K/Akt/mTOR pathway in a HuR-dependent manner.

Exosome therapeutics for non-small cell lung cancer tumorigenesis

Non-small cell lung cancer (NSCLC) remains an ongoing health concern, with poor treatment options and prognosis for many patients. Typically, individuals with lung cancer are detected at the middle and terminal stages, resulting in poor medical results due to lack of initial diagnosis and treatment. So, finding the initial specific and effective therapy options for lung cancer is necessary. In addition, exosomes are generally small lipid vesicles with a diameter in the nanometer range that are created and released by different cell types. Exosomes have therapeutic potential through delivering bioactive compounds including microRNAs, siRNAs, and therapeutic proteins to tumor cells, modifying the tumor microenvironment, and promoting anti-tumor immune responses. In recent years, exosome-based therapy has become known as an appropriate approach for NSCLC treatment. This review offers an overview of the possibility of exosome-based therapy for NSCLC, with an emphasis on mechanisms of action, preclinical research, and current clinical trials. Preclinical studies have shown that exosome-based therapy can decrease tumor growth, metastasis, and drug resistance in NSCLC models. Furthermore, ongoing clinical trials are looking at the safety and efficacy of exosome-based therapies in NSCLC patients, offering important insights into their translational prospects. Despite promising preclinical evidences, significant obstacles remain, including optimizing exosome isolation and purification techniques, standardizing production strategies, and developing scalable manufacturing processes. Overall, exosome-based therapy shows significant promise as a novel and various methods for treating NSCLC, with the potential to enhance patient outcomes and evolution cancer treatment.

JDF promotes the apoptosis of M2 macrophages and reduces epithelial-mesenchymal transition and migration of liver cancer cells by inhibiting CSF-1/PI3K/AKT signaling pathway

Background

The interaction between cancer cells and the tumor microenvironment is of critical importance in liver cancer. Jiedu Granule formula (JDF) has been shown to minimize the risk of recurrence and metastasis following liver cancer resection. Investigating the mechanism underlying the therapeutic effects of JDF can extend its field of application and develop novel treatment approaches.

Methods

We established a rat liver orthotopic transplantation tumor model, and recorded the prognostic effects of JDF adjuvant therapy on the recurrence and metastasis of liver cancer. Liver and lung tissues were collected for immunofluorescence staining and H&E staining, respectively. In addition, THP-1 cells were incubated with PMA and IL-4 to induce them to differentiate into M2 macrophages. CSF-1 expression was knocked down using lentivirus to determine the function of CSF-1. Liver cancer cells were cultured with a conditioned medium (CM) or co-cultured with macrophages. Cell viability was determined using the MTT assay. The levels of CSF-1, CSF-1R, E-cadherin, N-cadherin, PI3K, AKT, and cleaved caspase-3 were detected using ELISA, Western blotting and qPCR. The ability of cells to migrate was assessed using cell scratch and transwell assays. Apoptosis was evaluated using flow cytometry.

Results

The JDF treatment decreased the risk of liver cancer metastasis after surgery and the infiltration of CD206/CD68 cells in liver cancer tissue. In cell experiments, JDF showed effects in suppressing M2 macrophages activity and downregulating the expression of CSF-1 and CSF-1R. The concentration of CSF-1 in the supernatant was also lower in the JDF-treated group. Futhermore, M2-CM was found to promote cancer cell migration and epithelial-mesenchymal transition (EMT); however, these effects were weakened after administering JDF. Knocking down endogenous CSF-1 in M2 macrophages resulted in a comparable suppression of cancer cell migration and EMT. Additionally, JDF treatment inhibited activation of the PI3K/AKT pathway, thus promoting the apoptosis of M2 macrophages.

Conclusions

Treatment with JDF reduced the EMT and migratory capacity of liver cancer cells, which might be attributed to the inhibition of M2 macrophage infiltration and interruption of the CSF-1/PI3K/AKT signaling pathway. This mechanism may hold significant implications for mitigating the risk of metastatic spread in the aftermath of hepatic surgery.

Tissue-derived extracellular vesicles in cancer progression: mechanisms, roles, and potential applications

Extracellular vesicles (EVs) are small lipid bilayer-enclosed vesicles that mediate vital cellular communication by transferring cargo between cells. Among these, tissue-derived extracellular vesicles (Ti-EVs) stand out due to their origin from the tissue microenvironment, providing a more accurate reflection of changes in this setting. This unique advantage makes Ti-EVs valuable in investigating the intricate relationship between extracellular vesicles and cancer progression. Despite considerable research efforts exploring the association between Ti-EVs and cancers, a comprehensive clustering or grouping of these studies remains lacking. In this review, we aim to fill this gap by presenting a comprehensive synthesis of the mechanisms underlying Ti-EV generation, release, and transport within cancer tissues. Moreover, we delve into the pivotal roles that Ti-EVs play in cancer progression, shedding light on their potential as diagnostic and therapeutic tools. The review culminates in the construction of a comprehensive functional spectrum of Ti-EVs, providing a valuable reference for future research endeavors. By summarizing the current state of knowledge on Ti-EVs and their significance in tumor biology, this work contributes to a deeper understanding of cancer microenvironment dynamics and opens up avenues for harnessing Ti-EVs in diagnostic and therapeutic applications.

Exosomes: efficient macrophage-related immunomodulators in chronic lung diseases

Macrophages, the predominant immune cells in the lungs, play a pivotal role in maintaining the delicate balance of the pulmonary immune microenvironment. However, in chronic inflammatory lung diseases and lung cancer, macrophage phenotypes undergo distinct transitions, with M1-predominant macrophages promoting inflammatory damage and M2-predominant macrophages fostering cancer progression. Exosomes, as critical mediators of intercellular signaling and substance exchange, participate in pathological reshaping of macrophages during development of pulmonary inflammatory diseases and lung cancer. Specifically, in inflammatory lung diseases, exosomes promote the pro-inflammatory phenotype of macrophages, suppress the anti-inflammatory phenotype, and subsequently, exosomes released by reshaped macrophages further exacerbate inflammatory damage. In cancer, exosomes promote pro-tumor tumor-associated macrophages (TAMs); inhibit anti-tumor TAMs; and exosomes released by TAMs further enhance tumor proliferation, metastasis, and resistance to chemotherapy. Simultaneously, exosomes exhibit a dual role, holding the potential to transmit immune-modulating molecules and load therapeutic agents and offering prospects for restoring immune dysregulation in macrophages during chronic inflammatory lung diseases and lung cancer. In chronic inflammatory lung diseases, this is manifested by exosomes reshaping anti-inflammatory macrophages, inhibiting pro-inflammatory macrophages, and alleviating inflammatory damage post-reshaping. In lung cancer, exosomes reshape anti-tumor macrophages, inhibit pro-tumor macrophages, and reshaped macrophages secrete exosomes that suppress lung cancer development. Looking ahead, efficient and targeted exosome-based therapies may emerge as a promising direction for treatment of pulmonary diseases.

Long noncoding RNA MCM3AP-AS1 attenuates sepsis-induced cardiomyopathy by improving inflammation, oxidative stress, and mitochondrial function through mediating the miR-501-3p/CADM1/STAT3 axis

Oxidative stress and inflammation are highly important for sepsis-mediated myocardial damage. The long noncoding RNA (lncRNA) MCM3AP-AS1 is involved in inflammatory diseases, but its function in acute myocardial injury during sepsis has not been fully elucidated. LPS and cecal ligation and puncture (CLP) were used to construct in vitro and in vivo sepsis-induced myocardial damage models, respectively. qRT-PCR was used to evaluate alterations in MCM3AP-AS1 and miR-501-3p alterations. After the MCM3AP-AS1 and miR-501-3p knockdown or overexpression models were established, the viability, apoptosis, inflammation, oxidative stress, and mitochondrial function of the myocardial cells were examined. Dual luciferase activity assay, RNA immunoprecipitation, and fluorescence in situ hybridization (FISH) confirmed the correlation among MCM3AP-AS1, miR-501-3p, and CADM1. Previous studies revealed that MCM3AP-AS1 was downregulated in sepsis patients, myocardial cells treated with LPS, and in the CLP mouse sepsis model, whereas miR-501-3p expression was increased. MCM3AP-AS1 overexpression hampered myocardial damage mediated by LPS and abated inflammation, oxidative stress, and mitochondrial dysfunction in myocardial cells and THP-1 cells. In contrast, MCM3AP-AS1 knockdown or miR-501-3p overexpression promoted all the effects of LPS. In vivo, MCM3AP-AS1 overexpression increased the survival rate of CLP mice; ameliorated myocardial injury; decreased the levels of TNF-α, IL-1β, IL-6, iNOS, COX2, ICAM1, VCAM1, PGE2, and MDA; and increased the levels of SOD, GSH-PX, Nrf2, and HO-1. Mechanistic studies demonstrated that MCM3AP-AS1 acted as a competitive endogenous RNA to repress miR-501-3p, enhance CADM1 expression, and dampen STAT3/nuclear factor-kappaB (NF-κB) activation. MCM3AP-AS1 suppresses myocardial injury elicited by sepsis by mediating the miR-501-3p/CADM1/STAT3/NF-κB axis.

Tumor-associated macrophage-derived exosomal miR-513b-5p is a target of jianpi yangzheng decoction for inhibiting gastric cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Jianpi Yangzheng decoction (JPYZ) possesses a potential anti-tumor activity in gastric cancer. However, potential effect of JPYZ on regulating tumor-associated macrophage (TAM)-derived exosomes to affect gastric cancer is still unclear.

AIM OF STUDY

We aimed to clarify the role of tumor-associated macrophage derived exosomes (TAM-exos) in invasive and metastasis of gastric cancer and the mechanism of JPYZ regulate TAM-exos against gastric cancer.

MATERIALS AND METHODS

Flow cytometry was performed to demonstrate whether JPYZ involved in TAM polarization. After JPYZ treatment, TAM conditioned medium (TAM-CM)/TAM-exos were co-cultured with gastric cancer cells and were detected by wound healing and transwell assay. Transcriptome sequencing and bioinformatics analysis predicted the exosomal miRNA after JPYZ intervention in TAM. miRNA mimic and inhibitor were used to verify the effect of miRNA in exosomes on gastric cancer cells. Q-PCR and luciferase reporter assay were employed to clarify the targeting relationship between miRNA and target gene. Western blot assay detected the expression levels of epithelial-mesenchymal transition (EMT) markers and related signaling pathways proteins.

RESULTS

We firstly demonstrated that TAM-CM intervened by JPYZ significantly inhibited the invasion and migration of gastric cancer. Furthermore, exosomes in TAM supernatants play a key role in migration of gastric cancer. Meanwhile, transcriptome sequencing and q-PCR revealed that miR-513b-5p expression was significantly reduced in TAM-exos intervened by JPYZ. And miR-513b-5p in TAM aggravated TAM-exos mediated invasion and migration of gastric cancer cells, the inhibitor of miR-513b-5p reversed TAM-exos mediated promotion. Bioinformatics analysis and luciferase reporter assay confirmed that PTEN was a direct target of miR-513b-5p in gastric cancer. MiR-513b-5p inhibited PTEN to activate AKT/mTOR signaling pathway thus promoting gastric cancer invasion and metastasis in vivo and in vitro. Importantly, JPYZ inhibited TAM derived exosomal miR-513b-5p, and alleviated AKT/mTOR activation by PTEN depended manner in gastric cancer.

CONCLUSION

TAM-exos containing miR-513b-5p lead to gastric cancer invasion and migration. Our findings clarify a novel TAM-exos mechanism of JPYZ for inhibiting gastric cancer progression.

Macrophages-derived exo-miR-4449 induced by Cryptococcus affects HUVEC permeability and promotes pyroptosis in BEAS-2B via the HIC1 pathway

Macrophages have recently been discovered to assume a significant role in the progression of cryptococcosis. However, the potential involvement of macrophage-derived exosomes in the pathogenesis of cryptococcosis remains uncertain. In this study, we investigated the changes of microRNAs in macrophage exosomes (exo-miRNAs) in cryptococcal infections and the role of markedly altered exo-miRNAs in the modulation of Human Umbilical Vein Endothelial Cells (HUVEC) permeability and ROS accumulation and pyroptosis in Human Bronchial Epithelioid Cells (BEAS-2B). Techniques such as microarray analysis and real-time quantitative PCR were used to detect different exo-miRNAs and to screen for the most highly expressed exo-miRNAs. Then its mimics were transfected into HUVEC to study its effect on the monolayer permeability of HUVEC. Finally, the relationship between this exo-miRNAs and the ROS accumulation and pyroptosis was verified by bioinformatics analysis. The results showed that five exo-miRNAs were overexpressed and two exo-miRNAs were reduced, among which, exo-miR-4449 was expressed at the highest level. Exo-miR-4449 could be internalized by HUVEC and enhanced its monolayer permeability. Moreover, exo-miR-4449 was found to promote ROS accumulation and pyroptosis in BEAS-2B through HIC1 pathway. Thus, exo-miR-4449 plays an important role in the pathogenesis of cryptococcosis and holds promise as a significant biomarker for treatment.

Targeting tumor-associated macrophage: an adjuvant strategy for lung cancer therapy

The emergence of immunotherapy has revolutionized the treatment landscape for various types of cancer. Nevertheless, lung cancer remains one of the leading causes of cancer-related mortality worldwide due to the development of resistance in most patients. As one of the most abundant groups of immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play crucial and complex roles in the development of lung cancer, including the regulation of immunosuppressive TME remodeling, metabolic reprogramming, neoangiogenesis, metastasis, and promotion of tumoral neurogenesis. Hence, relevant strategies for lung cancer therapy, such as inhibition of macrophage recruitment, TAM reprograming, depletion of TAMs, and engineering of TAMs for drug delivery, have been developed. Based on the satisfactory treatment effect of TAM-targeted therapy, recent studies also investigated its synergistic effect with current therapies for lung cancer, including immunotherapy, radiotherapy, chemotherapy, anti-epidermal growth factor receptor (anti-EGFR) treatment, or photodynamic therapy. Thus, in this article, we summarized the key mechanisms of TAMs contributing to lung cancer progression and elaborated on the novel therapeutic strategies against TAMs. We also discussed the therapeutic potential of TAM targeting as adjuvant therapy in the current treatment of lung cancer, particularly highlighting the TAM-centered strategies for improving the efficacy of anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) treatment.

Key role of exosomes derived from M2 macrophages in maintaining cancer cell stemness (Review)

Cancer stem cells (CSCs) constitute a specific subset of cells found within tumors that are responsible for initiating, advancing and resisting traditional cancer treatments. M2 macrophages, also known as alternatively activated macrophages, contribute to the development and progression of cancer through their involvement in promoting angiogenesis, suppressing the immune system, supporting tumor growth and facilitating metastasis. Exosomes, tiny vesicles released by cells, play a crucial role in intercellular communications and have been shown to be associated with cancer development and progression by influencing the immune response; thus, they may serve as markers for diagnosis and prognosis. Currently, investigating the impact of exosomes derived from M2 macrophages on the maintenance of CSCs is a crucial area of research with the aim of developing novel therapeutic strategies to target this process and improve outcomes for individuals with cancer. Understanding the biological functions of exosomes derived from M2 macrophages and their involvement in cancer may lead to the formulation of novel diagnostic tools and treatments for this disease. By targeting M2 macrophages and the exosomes they secrete, promising prospects emerge for cancer treatment, given their substantial contribution to cancer development and progression. Further research is required to fully grasp the intricate interactions between CSCs, M2 macrophages and exosomes in cancer, and to identify fresh targets for cancer therapy. The present review explores the pivotal roles played by exosomes derived from M2 cells in maintaining the stem‑like properties of cancer cells.

The Role of Exosome-Derived microRNA on Lung Cancer Metastasis Progression

The high mortality from lung cancer is mainly attributed to the presence of metastases at the time of diagnosis. Despite being the leading cause of lung cancer death, the underlying molecular mechanisms driving metastasis progression are still not fully understood. Recent studies suggest that tumor cell exosomes play a significant role in tumor progression through intercellular communication between tumor cells, the microenvironment, and distant organs. Furthermore, evidence shows that exosomes release biologically active components to distant sites and organs, which direct metastasis by preparing metastatic pre-niche and stimulating tumorigenesis. As a result, identifying the active components of exosome cargo has become a critical area of research in recent years. Among these components are microRNAs, which are associated with tumor progression and metastasis in lung cancer. Although research into exosome-derived microRNA (exosomal miRNAs) is still in its early stages, it holds promise as a potential target for lung cancer therapy. Understanding how exosomal microRNAs promote metastasis will provide evidence for developing new targeted treatments. This review summarizes current research on exosomal miRNAs' role in metastasis progression mechanisms, focusing on lung cancer.

Exosomal miRNAs assist in the crosstalk between tumor cells and immune cells and its potential therapeutics

Exosomes are small extracellular vesicles that carry active substances (including proteins, lipids, and nucleic acids) and are essential for homeostasis and signal transmission. Recent studies have focused on the function of exosomal miRNAs in tumor progression. Researchers have expanded the use of exosomes and miRNAs as potential therapeutic tools and biomarkers to detect tumor progression. Immune cells, as an important part of the tumor microenvironment (TME), secrete a majority of exosome-derived miRNAs involved in the biological processes of malignancies. However, the underlying mechanisms remain unclear. Currently, there is no literature that systematically summarizes the communication of exosome-derived miRNAs between tumor cells and immune cells. Based on the cell specificity of exosome-derived miRNAs, this review provides the first comprehensive summary of the significant miRNAs from the standpoint of exosome sources, which are tumor cells and immune cells. Furthermore, we elaborated on the potential clinical applications of these miRNAs, attempting to propose existing difficulties and future possibilities in tumor diagnostics and therapy.

Potential roles of exosomes in the initiation and metastatic progression of lung cancer

Lung cancer (LC) incidence and mortality continue to increase annually worldwide. LC is insidious and readily metastasizes and relapses. Except for its early diagnosis and surgical resection, there is no effective cure for advanced metastatic LC, and the prognosis remains dismal. Exosomes, a class of nano-sized extracellular vesicles produced by healthy or diseased cells, are coated with a bilayer lipid membrane and contain various functional molecules such as proteins, lipids, and nucleic acids. They can be used for intracellular or intercellular signaling or the transportation of biological substances. A growing body of evidence supports that exosomes play multiple crucial roles in the occurrence and metastatic progression of many malignancies, including LC. The elucidation of the potential roles of exosomes in the initiation, invasion, and metastasis of LC and their underlying molecular mechanisms may contribute to improved early diagnosis and treatment.

Roles of hypoxic environment and M2 macrophage-derived extracellular vesicles on the progression of non-small cell lung cancer

BACKGROUND

Hypoxia contributes to the development of invasive and metastatic cancer cells, and is detrimental to cancer treatment. This study aimed to explore the molecular mechanisms by which hypoxic microenvironments affect hypoxic non-small cell lung cancer (NSCLC) development and the effects of M2 macrophage-derived extracellular vesicles (EVs) on NSCLC cells.

METHODS

A549 cells were cultured in an anoxic incubator for 48 h to construct hypoxic A549 cells, and then normal and hypoxic A549 cells were harvested for RNA sequencing. Next, THP-1 cells were used to induce M2 macrophages, and EVs were isolated from THP-1 cells and M2 macrophages. Cell counting kit-8 and transwell assays were used to determine the viability and migration of hypoxic A549 cells, respectively.

RESULTS

After sequencing, 2426 DElncRNAs and 501 DEmiRNAs were identified in normal A549 cells and hypoxic A549 cells. These DElncRNAs and DEmiRNAs were significantly enriched in "Wnt signaling pathway," "Hippo signaling pathway," "Rap1 signaling pathway," "calcium signaling pathway," "mTOR signaling pathway," and "TNF signaling pathway." Subsequently, ceRNA networks consisting of 4 lncRNA NDRG1 transcripts, 16 miRNAs and 221 target mRNAs were built, and the genes in the ceRNA networks were significantly associated with "Hippo signaling pathway" and "HIF-1 signaling pathway." EVs were successfully extracted from THP-1 cells and M2 macrophages, and M2 macrophage-derived EVs significantly enhanced the viability and migration of hypoxic A549 cells. Finally, M2 macrophage-derived EVs further upregulated the expression of NDRG1-009, NDRG1-006, VEGFA, and EGLN3, while downregulating miR-34c-5p, miR-346, and miR-205-5p in hypoxic A549 cells.

CONCLUSIONS

M2 macrophage-derived EVs may worsen the progression of NSCLC in a hypoxic microenvironment by regulating the NDRG1-009-miR-34c-5p-VEGFA, NDRG1-006-miR-346-EGLN3, NDRG1-009-miR-205-5p-VEGFA, and Hippo/HIF-1 signaling pathways.

WDR82-Mediated H3K4me3 Is Associated with Tumor Proliferation and Therapeutic Efficacy in Pediatric High-Grade Gliomas

Pediatric high-grade gliomas (pHGGs) are common malignant brain tumors without effective treatment and poor patient survival. Abnormal posttranslational modification at the histone H3 tail plays critical roles in tumor cell malignancy. We have previously shown that the trimethylation of lysine 4 at histone H3 (H3K4me3) plays a significant role in pediatric ependymoma malignancy and is associated with tumor therapeutic sensitivity. Here, we show that H3K4me3 and its methyltransferase WDR82 are elevated in pHGGs. A reduction in H3K4me3 by downregulating WDR82 decreases H3K4me3 promoter occupancy and the expression of genes associated with stem cell features, cell proliferation, the cell cycle, and DNA damage repair. A reduction in WDR82-mediated H3K4me3 increases the response of pediatric glioma cells to chemotherapy. These findings suggest that WDR82-mediated H3K4me3 is an important determinant of pediatric glioma malignancy and therapeutic response. This highlights the need for a more thorough understanding of the potential of WDR82 as an epigenetic target to increase therapeutic efficacy and improve the prognosis for children with malignant gliomas.

Epigenetic regulation and therapeutic targets in the tumor microenvironment

The tumor microenvironment (TME) is crucial to neoplastic processes, fostering proliferation, angiogenesis and metastasis. Epigenetic regulations, primarily including DNA and RNA methylation, histone modification and non-coding RNA, have been generally recognized as an essential feature of tumor malignancy, exceedingly contributing to the dysregulation of the core gene expression in neoplastic cells, bringing about the evasion of immunosurveillance by influencing the immune cells in TME. Recently, compelling evidence have highlighted that clinical therapeutic approaches based on epigenetic machinery modulate carcinogenesis through targeting TME components, including normalizing cells' phenotype, suppressing cells' neovascularization and repressing the immunosuppressive components in TME. Therefore, TME components have been nominated as a promising target for epigenetic drugs in clinical cancer management. This review focuses on the mechanisms of epigenetic modifications occurring to the pivotal TME components including the stroma, immune and myeloid cells in various tumors reported in the last five years, concludes the tight correlation between TME reprogramming and tumor progression and immunosuppression, summarizes the current advances in cancer clinical treatments and potential therapeutic targets with reference to epigenetic drugs. Finally, we summarize some of the restrictions in the field of cancer research at the moment, further discuss several interesting epigenetic gene targets with potential strategies to boost antitumor immunity.

Non-coding RNA-based therapeutics in cancer therapy: An emphasis on Wnt/β-catenin control

Non-coding RNA transcripts are RNA molecules that have mainly regulatory functions and they do not encode proteins. microRNAs (miRNAs), lncRNAs and circRNAs are major types of this family and these epigenetic factors participate in disease pathogenesis, especially cancer that their abnormal expression may lead to cancer progression. miRNAs and lncRNAs possess a linear structure, whereas circRNAs possess ring structures and high stability. Wnt/β-catenin is an important factor in cancer with oncogenic function and it can increase growth, invasion and therapy resistance in tumors. Wnt upregulation occurs upon transfer of β-catenin to nucleus. Interaction of ncRNAs with Wnt/β-catenin signaling can determine tumorigenesis. Wnt upregulation is observed in cancers and miRNAs are able to bind to 3'-UTR of Wnt to reduce its level. LncRNAs can directly/indirectly regulate Wnt and in indirect manner, lncRNAs sponge miRNAs. CircRNAs are new emerging regulators of Wnt and by its stimulation, they increase tumor progression. CircRNA/miRNA axis can affect Wnt and carcinogenesis. Overall, interaction of ncRNAs with Wnt can determine proliferation rate, migration ability and therapy response of cancers. Furthermore, ncRNA/Wnt/β-catenin axis can be utilized as biomarker in cancer and for prognostic applications in patients.

Exosomal Non-Coding RNAs: Novel Regulators of Macrophage-Linked Intercellular Communication in Lung Cancer and Inflammatory Lung Diseases

Macrophages are innate immune cells and often classified as M1 macrophages (pro-inflammatory states) and M2 macrophages (anti-inflammatory states). Exosomes are cell-derived nanovesicles that range in diameter from 30 to 150 nm. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are abundant in exosomes and exosomal ncRNAs influence immune responses. Exosomal ncRNAs control macrophage-linked intercellular communication via their targets or signaling pathways, which can play positive or negative roles in lung cancer and inflammatory lung disorders, including acute lung injury (ALI), asthma, and pulmonary fibrosis. In lung cancer, exosomal ncRNAs mediated intercellular communication between lung tumor cells and tumor-associated macrophages (TAMs), coordinating cancer proliferation, migration, invasion, metastasis, immune evasion, and therapy resistance. In inflammatory lung illnesses, exosomal ncRNAs mediate macrophage activation and inflammation to promote or inhibit lung damage. Furthermore, we also discussed the possible applications of exosomal ncRNA-based therapies for lung disorders.

M2 macrophages-derived exosomal miR-3917 promotes the progression of lung cancer via targeting GRK6

Macrophages in the tumor microenvironment (TME) can serve as potential targets for therapeutic intervention. The aim of this study was to investigate the molecular mechanism by which M2 macrophage-derived exosomes (M2-Ex) affect lung cancer progression through miRNA transport. The THP-1 cells were differentiated into M0 and M2 macrophages. M2-Ex were isolated and identified by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Cancer tissues and adjacent tissues of non-small-cell lung cancer (NSCLC) patients were collected. H1299 and A549 cells were co-cultured with M2-Ex. Subcutaneous xenograft mouse model was established. miR-3917 is highly expressed in lung cancer tissues and M2-Ex. Interference of miR-3917 in M2-Ex inhibits H1299 cell proliferation, migration and invasion, while overexpression of miR-3917 had the opposite effect in A549 cells. M2-Ex promote tumor growth by delivering miR-3917 in vivo. miR-3917 could target G protein-coupled receptor kinase 6 (GRK6), and interference of miR-3917 in M2-Ex inhibits H1299 cells proliferation, migration and invasion by up-regulating GRK6 level, while overexpression of miR-3917 had the opposite effect in A549 cells. M2-Ex can transfer miR-3917 into lung cancer cells and promote lung cancer progression, providing theoretical basis for the diagnosis and effective treatment of lung cancer.

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.

Pro-tumoral functions of tumor-associated macrophage EV-miRNA

MicroRNAs (miRNAs) are central players in cancer biology. Their relevance in cancer development, progression and resistance to therapy has been further emphasized by the discovery that they are important cargo component of extracellular vesicles (EVs), which represent a prominent means of inter-cellular communication within the tumor microenvironment (TME). This review article focuses on the interaction between cancer cells and tumor-associated macrophages (TAMs) and in particular on the pro-tumoral phenotype elicited by EV-contained miRNAs released by TAMs and transferred to cancer cells. All main hallmarks of the malignant phenotype are affected by TAM-derived vesicular miRNAs, paving the road to the identification of such miRNAs as promising upcoming novel anti-cancer agents.

Tumor microenvironment in lung cancer-derived brain metastasis

ABSTRACT

Brain metastasis (BM) is the leading cause of mortality in lung cancer patients. The process of BM (from initial primary tumor development, migration and intravasation, dissemination and survival in the bloodstream, extravasation, to colonization and growth to metastases) is a complex process for which few tumor cells complete the entire process. Recent research on BM of lung cancer has recently stressed the essential role of tumor microenvironment (TME) in assisting tumor cells in the completion of each BM step. This review summarizes recent studies regarding the effects of TME on tumor cells in the entire process of BM derived from lung cancer. The identification of vulnerable targets in the TME and their prospects to provide novel therapeutic opportunities are also discussed.

Macrophage-Derived Small Extracellular Vesicles in Multiple Diseases: Biogenesis, Function, and Therapeutic Applications

Macrophages (Mφs), as immune cells, play a pivotal role against pathogens and many diseases, such as cancer, inflammation, cardiovascular diseases, orthopedic diseases, and metabolic disorders. In recent years, an increasing number of studies have shown that small extracellular vesicles (sEVs) derived from Mφs (M-sEVs) play important roles in these diseases, suggesting that Mφs carry out their physiological functions through sEVs. This paper reviews the mechanisms underlying M-sEVs production via different forms of polarization and their biological functions in multiple diseases. In addition, the prospects of M-sEVs in disease diagnosis and treatment are described.

An Eleven-microRNA Signature Related to Tumor-Associated Macrophages Predicts Prognosis of Breast Cancer

The dysregulation of microRNAs (miRNAs) has been known to play important roles in tumor development and progression. However, the understanding of the involvement of miRNAs in regulating tumor-associated macrophages (TAMs) and how these TAM-related miRNAs (TRMs) modulate cancer progression is still in its infancy. This study aims to explore the prognostic value of TRMs in breast cancer via the construction of a novel TRM signature. Potential TRMs were identified from the literature, and their prognostic value was evaluated using 1063 cases in The Cancer Genome Atlas Breast Cancer database. The TRM signature was further validated in the external Gene Expression Omnibus GSE22220 dataset. Gene sets enrichment analyses were performed to gain insight into the biological functions of this TRM signature. An eleven-TRM signature consisting of mir-21, mir-24-2, mir-125a, mir-221, mir-22, mir-501, mir-365b, mir-660, mir-146a, let-7b and mir-31 was constructed. This signature significantly differentiated the high-risk group from the low-risk in terms of overall survival (OS)/ distant-relapse free survival (DRFS) (p value < 0.001). The prognostic value of the signature was further enhanced by incorporating other independent prognostic factors in a nomogram-based prediction model, yielding the highest AUC of 0.79 (95% CI: 0.72−0.86) at 5-year OS. Enrichment analyses confirmed that the differentially expressed genes were mainly involved in immune-related pathways such as adaptive immune response, humoral immune response and Th1 and Th2 cell differentiation. This eleven-TRM signature has great potential as a prognostic factor for breast cancer patients besides unravelling the dysregulated immune pathways in high-risk breast cancer.

Emerging function and clinical significance of extracellular vesicle noncoding RNAs in lung cancer

Lung cancer (LC) is a commonly diagnosed cancer with an unsatisfactory prognosis. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that mediate cell-cell communication by transporting various biomacromolecules, such as nucleic acids, proteins, and lipids. Noncoding RNAs (ncRNAs), including microRNAs, circular RNAs, and long noncoding RNAs, are important noncoding transcripts that play critical roles in a variety of physiological and pathological processes, especially in cancer. ncRNAs have been verified to be packaged into EVs and transported between LC cells and stromal cells, regulating multiple LC malignant phenotypes, such as proliferation, migration, invasion, epithelial-mesenchymal transition, metastasis, and treatment resistance. Additionally, EVs can be detected in various body fluids and are associated with the stage, grade, and metastasis of LC. Herein, we summarize the biological characteristics and functions of EV ncRNAs in the biological processes of LC, focusing on their potential to serve as diagnostic and prognostic biomarkers of LC as well as their probable role in the clinical treatment of LC. EV ncRNAs provide a new perspective for understanding the mechanism underlying LC pathogenesis and development, which might benefit numerous LC patients in the future.

microRNA-155-3p delivered by M2 macrophages-derived exosomes enhances the progression of medulloblastoma through regulation of WDR82

Objective

Exosomes, membranous nanovesicles, naturally bringing proteins, mRNAs, and microRNAs (miRNAs), play crucial roles in tumor pathogenesis. This study was to investigate the role of miR-155-3p from M2 macrophages-derived exosomes (M2-Exo) in promoting medulloblastoma (MB) progression by mediating WD repeat domain 82 (WDR82).

Methods

miR-155-3p expression was detected by RT-qPCR. The relationship of miR-155-3p with clinicopathological features of MB patients was analyzed. M2-Exo were isolated and identified by TEM, NTA and Western blot. CCK-8 assay, colony formation assay, flow cytometry, wound healing assay, and Transwell assay were performed to explore the role of miR-155-3p-enriched M2-Exo on the progression of MB cells. Luciferase assay were used to identify the relationship between miR-155-3p and WDR82. The effect of miR-155-3p-enriched M2-Exo on tumorigenesis of MB was confirmed by the xenograft nude mice model.

Results

miR-155-3p was up-regulated in MB tissues of patients and MB cell lines. High miR-155-3p expression was correlated with the pathological type and molecular subtype classification of MB patients. WDR82 was a direct target of miR-155-3p. miR-155-3p was packaged into M2-Exo. miR-155-3p-enriched M2-Exo promoted the progression of Daoy cells. miR-155-3p-enriched M2-Exo promoted in vivo tumorigenesis.

Conclusion

The study highlights that miR-155-3p-loaded M2-Exo enhances the growth of MB cells via down-regulating WDR82, which might provide a deep insight into MB mechanism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03156-y.

Epigenetic regulation of immunosuppressive tumor-associated macrophages through dysregulated microRNAs

Macrophages are immune cells that play different roles under different physiological conditions. They are present in all tissues where they primarily protect from bacteria and pathogens in addition to assisting in tissue repair. During tumor progression, macrophages can exert contrasting effects based on the M1 vs. M2 polarization. The M2 macrophages support tumor growth through mechanisms that help suppress immune responses and/or circumvent immune-surveillance. A number of such mechanisms such as production of IL-10 and arginase, and expression of PD-L1, V-domain Ig suppressor of T cell activation and B7 family molecule B7-H4 are now believed central to the immunosuppressive effects of tumor-associated macrophages (TAMs). Emerging data has identified epigenetic regulation of these immunosuppressive mechanisms by small non-coding RNAs, the microRNAs (miRNAs). This review discusses the available literature on the subject, including the exosomes mediated transfer of miRNAs between cancer cells and the macrophages within the tumor microenvironment. A number of miRNAs are now believed to be involved in TAMs' production of IL-10 and expression of PD-L1 while the information on such regulation of other immunosuppressive mechanisms is slowly emerging. A better understanding of epigenetic regulation of macrophages-mediated immunosuppressive effect can help identify novel targets for therapy and aid the design of future studies aimed at sensitizing tumors to immune responses.