The Immunomodulation Potential of Exosomes in Tumor Microenvironment

On-Site Stimulation of Dendritic Cells by Cancer-Derived Extracellular Vesicles on a Core-Shell Nanowire Platform

Extracellular vesicles (EVs) contain a subset of proteins, lipids, and nucleic acids that maintain the characteristics of the parent cell. Immunotherapy using EVs has become a focus of research due to their unique features and bioinspired applications in cancer treatment. Unlike conventional immunotherapy using tumor fragments, EVs can be easily obtained from bodily fluids without invasive actions. We previously fabricated nanowire devices that were specialized for EV collection, but they were not suitable for cell culturing. In this study, we fabricated a ZnO/Al2O3 core-shell nanowire platform that could collect more than 60% of the EVs from the cell supernatant. Additionally, we could continue to culture dendritic cells (DCs) on the platform as an artificial lymph node to investigate cell maturation into antigen-presenting cells. Finally, using this platform, we reproduced a series of on-site immune processes that are among the pivotal immune functions of DCs and include such processes as antigen uptake, antigen presentation, and endocytosis of cancer-derived EVs. This platform provides a new ex vivo tool for EV-DC-mediated immunotherapies.

Chemokine ligand 14 correlates with immune cell infiltration in the gastric cancer microenvironment in predicting unfavorable prognosis

Objective

Gastric cancer (GC) is the world's third-leading cause of cancer-related mortality; the prognosis for GC patients remains poor in terms of a lack of reliable biomarkers for early diagnosis and immune therapy response prediction. Here, we aim to discover the connection between chemokine ligand 14 (CCL14) expression in the gastric tumor microenvironment (TME) and its clinical significance and investigate its correlation with immune cell infiltration.

Methods

We assessed CCL14 mRNA expression and its interrelation with tumor-infiltrating immune cells (TILs) using bioinformatics analysis in gastric cancer. CCL14 protein expression, TILs, and immune checkpoints were detected by multiple immunohistochemistry analyses in gastric cancer tissue microarrays. Then, we conducted statistics analysis to determine the association between CCL14-related patient survival and immune cell infiltration (p < 0.05).

Results

We found that the CCL14 protein was separately expressed in the carcinoma cells and TILs in stomach cancer tissues. The CCL14 protein was related to tumor differentiation and tumor depth and positively correlated with the presentation of LAG3 and PD-L1 in gastric cancer cells. In addition, the CCL14 protein in the TILs of gastric cancer tissues was related to Lauren's type cells, T cells (CD4+ and CD8+), and CD68+ macrophages in the TME. Kaplan-Meier survival and multivariate analyses showed that the CCL14 expression in gastric cancer cells was an independent prognostic factor.

Conclusion

Our study illustrated that CCL14 is a poor prognosis biomarker in gastric cancer, which may be associated with the potential for immunotherapy.

Tumor cell-derived exosomal miR-193b-3p promotes tumor-associated macrophage activation to facilitate nasopharyngeal cancer cell invasion and radioresistances

Background

Communication between cancer cells and tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) plays a crucial role in accelerating nasopharyngeal cancer (NPC) metastasis and radioresistance. However, the mechanisms through which NPC cells regulate the properties and activation of TAMs during NPC progression are not yet fully understood.

Methods

A high-metastatic NPC subclone (HMC) and a low-metastatic NPC subclone (LMC) were screened from the CNE-2 cell line and exosomes were collected from HMCs and LMCs, respectively. The effects of HMC- and LMC-derived exosomes (HMC-Exos and LMC-Exos) on the regulation of TAM activation were evaluated by assessing the levels of inflammation-related or immunosuppression-related genes. The role of miRNA-193b-3p (miR-193b) in mediating communication between NPCs and TAMs was assessed using real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot analysis, Transwell assays, and clonogenic survival assays.

Results

HMCs and HMC-Exos exhibited a greater capacity to facilitate macrophage protumorigenic activation than LMCs and LMC-Exos. miR-193b levels derived from HMC-Exos were higher than those from LMC-Exos, and miR-193b levels were higher in metastatic NPC tissue-derived TAMs than in non-metastatic NPC tissue-derived TAMs. The upregulated miR-193b was packaged into exosomes and transferred to macrophages. Functionally, miR-193b up-regulation accelerated TAM activation by directly targeting mitogen-activated protein/ERK kinase kinase 3 (MEKK3). As a result, miR-193b-overexpressed macrophages facilitated NPC cell invasion and radioresistance.

Conclusions

These data revealed a critical role for exosomal miR-193b in mediating intercellular communication between NPC cells and macrophages, providing a potential target for NPC treatment.

Exosomes derived from colorectal cancer cells take part in activation of stromal fibroblasts through regulating PHLPP isoforms

Given that tumor cells primarily instigate systemic changes through exosome secretion, our study delved into the role of colorectal cancer (CRC)-secreted exosomal miR-224 in stromal reprogramming and its impact on endothelial cell angiogenesis. Furthermore, we assessed the potential clinical significance of a specific signature of circulating serum-derived miRNAs, serving as a non-invasive biomarker for CRC diagnosis. Circulating serum-derived miR-103a-3p, miR-135b-5p, miR-182-5p, and miR-224-5p were significantly up-regulated, while miR-215-5p, and miR-455-5p showed a significant down-regulation in CRC patients than in healthy individuals. Our findings indicated that the expressions of CAF-specific markers (α-SMA and FAP) and CAF-derived cytokines (IL-6, and SDF-1) were induced in fibroblasts stimulated with SW480 CRC exosomes, partly due to Akt activation. As a plausible mechanism, exosomal transfer of miR-224 from SW40 CRC cells may activate stromal fibroblasts, which in turn, may promote endothelial cell sprouting. The study identified PHLPP1 and PHLPP2 as direct targets of miR-224 and demonstrated that CRC-secreted exosomal miR-224 activates Akt signaling by regulating PHLPP1/2 in activated fibroblasts, thereby affecting the stromal cell proliferation and migration. This study established a panel of six-circulating serum-derived miRNAs as a non-invasive biomarker for CRC diagnosis. Also, we proposed a supporting model in which CRC-secreted exosomal miR-224 takes part in the stromal reprogramming to CAFs partly through regulating Akt signaling. This may affect the malignant biological behavior of activated stromal cells and thereby elicit a vascular response within the microenvironment of CRC cells. See also the graphical abstract(Fig. 1).

Extracellular vesicle-mediated communication between CD8+ cytotoxic T cells and tumor cells

Tumors pose a significant global public health challenge, resulting in numerous fatalities annually. CD8+ T cells play a crucial role in combating tumors; however, their effectiveness is compromised by the tumor itself and the tumor microenvironment (TME), resulting in reduced efficacy of immunotherapy. In this dynamic interplay, extracellular vesicles (EVs) have emerged as pivotal mediators, facilitating direct and indirect communication between tumors and CD8+ T cells. In this article, we provide an overview of how tumor-derived EVs directly regulate CD8+ T cell function by carrying bioactive molecules they carry internally and on their surface. Simultaneously, these EVs modulate the TME, indirectly influencing the efficiency of CD8+ T cell responses. Furthermore, EVs derived from CD8+ T cells exhibit a dual role: they promote tumor immune evasion while also enhancing antitumor activity. Finally, we briefly discuss current prevailing approaches that utilize functionalized EVs based on tumor-targeted therapy and tumor immunotherapy. These approaches aim to present novel perspectives for EV-based tumor treatment strategies, demonstrating potential for advancements in the field.

Protein cargo in extracellular vesicles as the key mediator in the progression of cancer

Exosomes are small vesicles of endosomal origin that are released by almost all cell types, even those that are pathologically altered. Exosomes widely participate in cell-to-cell communication via transferring cargo, including nucleic acids, proteins, and other metabolites, into recipient cells. Tumour-derived exosomes (TDEs) participate in many important molecular pathways and affect various hallmarks of cancer, including fibroblasts activation, modification of the tumour microenvironment (TME), modulation of immune responses, angiogenesis promotion, setting the pre-metastatic niche, enhancing metastatic potential, and affecting therapy sensitivity and resistance. The unique exosome biogenesis, composition, nontoxicity, and ability to target specific tumour cells bring up their use as promising drug carriers and cancer biomarkers. In this review, we focus on the role of exosomes, with an emphasis on their protein cargo, in the key mechanisms promoting cancer progression. We also briefly summarise the mechanism of exosome biogenesis, its structure, protein composition, and potential as a signalling hub in both normal and pathological conditions. Video Abstract.

Role of exosomes in prostate cancer and male fertility

Prostate cancer (PCa) is the second most common and fifth most aggressive neoplasm among men worldwide. In the last decade, extracellular vesicle (EV) research has decoded multiple unsolved cancer-related mysteries. EVs can be classified as microvesicles, apoptotic bodies, and exosomes, among others. Exosomes play a key role in cellular signaling. Their internal cargos (nucleic acids, proteins, lipids) influence the recipient cell. In PCa, the exosome is the regulator of cancer progression. It is also a promising theranostics tool for PCa. Moreover, exosomes have strong participation in male fertility complications. This review aims to highlight the exosome theranostics signature in PCa and its association with male fertility.

A Novel Electrochemical Differentiation between Exosomal-RNA of Breast Cancer MCF7 and MCF7/ADR-Resistant Cells

Cancer is considered one of the most burdensome diseases affecting lives and, hence, the economy. Breast cancer is one of the most common types of cancer. Patients with breast cancer are divided into two groups: one group responds to the chemotherapy, and the other group resists the chemotherapy. Unfortunately, the group which resists the chemotherapy is still suffering the pain associated with the severe side effects of the chemotherapy. Therefore, there is a critical need for a method to differentiate between both groups before the administration of the chemotherapy. Exosomes, the recently discovered nano-vesicles, are often used as cancer diagnostic biomarkers as their unique composition allows them to represent their parental cells, which makes them promising indicators for tumor prognosis. Exosomes contain proteins, lipids, and RNA that exist in most body fluids and are expelled by multiple cell types, including cancer cells. Furthermore, exosomal RNA has been significantly used as a promising biomarker for tumor prognosis. Herein, we have developed an electrochemical system that could successfully differentiate between MCF7 and MCF7/ADR depending on the exosomal RNA. The high sensitivity of the proposed electrochemical assay opens the door for further investigation that will address the other type of cancer cells.

Exosomal microRNAs in the DLK1-DIO3 imprinted region derived from cancer-associated fibroblasts promote progression of hepatocellular carcinoma by targeting hedgehog interacting protein

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most commonly diagnosed cancer and third leading cause of cancer-related death worldwide in 2020. Exosomes derived from cancer-associated fibroblasts (CAFs-exo) can promote tumor progression in various human cancers. However, the underlying regulatory mechanism controlling how CAFs-exo can promote HCC progression remains poorly understood.

METHODS

CAFs and para-cancer fibroblasts (PAFs) were isolated from HCC tissues and corresponding para-cancer tissues, then were cultured in vitro. CAFs and PAFs were characterized by immunofluorescence and western blot (WB) assays. Exosomes were isolated by ultracentrifugation, and characterized by transmission electron microscopy, nanoflow cytometry, and WB assay. The internalization of exosomes by HCC cells was observed under a fluorescence microscope. Cell Counting Kit-8 (CCK-8) assay was used to evaluate cell proliferation. Wound healing and transwell assays were used for migration and invasion experiments. RT-PCR assay was used to examine differentially expressed microRNAs (miRNAs) in exosomes and HCC cells. The TargetScan database was used to predict miRNA target genes. Hedgehog interacting protein (HHIP) expression analysis, prognostic analysis, and enrichment analysis of HHIP-related co-expressed genes were performed using the TIMER, UALCAN, Kaplan-Meier plotter, and LinkedOmics databases.

RESULTS

CAFs-exo were internalized by HCC cells. CAFs-exo contributed to the aggressive phenotype of HCC cells, while inhibiting exosome secretion reversed these effects. Mechanistically, miRNAs in the DLK1-DIO3 imprinted region (miR-329-3p, miR-380-3p, miR-410-5p, miR-431-5p) were increased in HCC cells co-cultured with CAFs-exo compared with PAFs-exo. Expression of HHIP, a possible miR-431-5p target gene, was significantly downregulated in HCC cells. Low HHIP expression level in tumor tissues could predict poor prognosis in HCC patients. HHIP-related co-expressed genes were mainly associated with cell adhesion molecules.

CONCLUSIONS

CAFs-exo can promote HCC progression by delivering miRNAs in the DLK1-DIO3 imprinted region to HCC cells, subsequently inhibiting HHIP expression. HHIP is a potential prognostic biomarker in HCC.

Molecular Docking and Intracellular Translocation of Extracellular Vesicles for Efficient Drug Delivery

Extracellular vesicles (EVs), including exosomes, mediate intercellular communication by delivering their contents, such as nucleic acids, proteins, and lipids, to distant target cells. EVs play a role in the progression of several diseases. In particular, programmed death-ligand 1 (PD-L1) levels in exosomes are associated with cancer progression. Furthermore, exosomes are being used for new drug-delivery systems by modifying their membrane peptides to promote their intracellular transduction via micropinocytosis. In this review, we aim to show that an efficient drug-delivery system and a useful therapeutic strategy can be established by controlling the molecular docking and intracellular translocation of exosomes. We summarise the mechanisms of molecular docking of exosomes, the biological effects of exosomes transmitted into target cells, and the current state of exosomes as drug delivery systems.

Functions and therapeutic potentials of exosomes in osteosarcoma

Osteosarcoma is a primary malignant tumor of the skeleton with the morbidity of 2.5 in 1 million. The regularly on-set is in the epiphysis of the extremities with a high possibility of early metastasis, rapid progression, and poor prognosis. The survival rate of patients with metastatic or recurrent osteosarcoma remains low, and novel diagnostic and therapeutic methods are urgently needed. Exosomes are extracellular vesicles 30-150 nm in diameter secreted by various cells that are widely present in various body fluids. Exosomes are abundant in biologically active components such as proteins, nucleic acids, and lipids. Exosomes participate in numerous physiological and pathological processes via intercellular substance exchange and signaling. This review presents the novel findings of exosomes in osteosarcoma in diagnosis, prognosis, and therapeutic aspects.

Extracellular vesicles: A new diagnostic biomarker and targeted drug in osteosarcoma

Osteosarcoma (OS) is a primary bone cancer that is highly prevalent among adolescents and adults below the age of 20 years. The prognostic outcome of metastatic OS or relapse is extremely poor; thus, developing new diagnostic and therapeutic strategies for treating OS is necessary. Extracellular vesicles (EVs) ranging from 30–150 nm in diameter are commonly produced in different cells and are found in various types of body fluids. EVs are rich in biologically active components like proteins, lipids, and nucleic acids. They also strongly affect pathophysiological processes by modulating the intercellular signaling pathways and the exchange of biomolecules. Many studies have found that EVs influence the occurrence, development, and metastasis of osteosarcoma. The regulation of inflammatory communication pathways by EVs affects OS and other bone-related pathological conditions, such as osteoarthritis and rheumatoid arthritis. In this study, we reviewed the latest findings related to diagnosis, prognosis prediction, and the development of treatment strategies for OS from the perspective of EVs.

Natural products exert anti-tumor effects by regulating exosomal ncRNA

Currently, more than 60% of the approved anti-cancer drugs come from or are related to natural products. Natural products and exosomal non-coding RNAs (ncRNAs) exert anti-cancer effects through various regulatory mechanisms, which are of great research significance. Exosomes are a form of intercellular communication and contain ncRNAs that can act as intercellular signaling molecules involved in the metabolism of tumor cells. This review exemplifies some examples of natural products whose active ingredients can play a role in cancer prevention and treatment by regulating exosomal ncRNAs, with the aim of illustrating the mechanism of action of exosomal ncRNAs in cancer prevention and treatment. Meanwhile, the application of exosomes as natural drug delivery systems and predictive disease biomarkers in cancer prevention and treatment is introduced, providing research ideas for the development of novel anti-tumor drugs.

Exosome-Mediated Immunosuppression in Tumor Microenvironments

Exosomes are membranous structures secreted by nearly all cell types. As critical messengers for intercellular communication, exosomes deliver bioactive cargoes to recipient cells and are involved in multiple physiopathological processes, including immunoregulation. Our pioneering study revealed that cancer cells release programmed death-ligand 1-positive exosomes into the circulation to counter antitumor immunity systemically via T cells. Tumor cell-derived exosomes (TDEs) also play an immunosuppressive role in other immunocytes, including dendritic cells (DCs), macrophages, natural killer (NK) cells, and myeloid-derived suppressor cells (MDSCs). Moreover, exosomes secreted by nontumor cells in the tumor microenvironments (TMEs) also exert immunosuppressive effects. This review systematically provides a summary of the immunosuppression induced by exosomes in tumor microenvironments, which modulates tumor growth, invasion, metastasis, and immunotherapeutic resistance. Additionally, therapeutic strategies targeting the molecular mechanism of exosome-mediated tumor development, which may help overcome several obstacles, such as immune tolerance in oncotherapy, are also discussed. Detailed knowledge of the specific functions of exosomes in antitumor immunity may contribute to the development of innovative treatments.

M2-Macrophage-Derived Exosomes Promote Meningioma Progression through TGF-β Signaling Pathway

Tumor-associated macrophages (TAMs) have been shown to be an essential component of the tumor microenvironment and facilitate the proliferation and invasion of a variety of malignancies. However, the contribution of TAMs to meningioma progression has not been characterized in detail. In this study, we aimed to discover a novel regulatory pathway by which exosome-mediated M2-polarized macrophages participate in meningioma tumorigenesis and progression. Methods. First, the distribution and functional phenotype of macrophages in meningioma tissues were assessed by immunohistochemistry. Macrophage-derived exosomes (MDEs) were characterized, and further cell coculture experiments were performed to explore the effects of M2-MDEs on the proliferation, migration, and invasion of meningioma cells. RNA sequencing was used to analyze the transcriptomic signatures in meningioma cells treated with M2-MDEs. Three-dimensional tumorspheres and xenograft tumor models were used to evaluate the effects of M2-MDEs on meningioma tumorigenesis and development. Results. We found that M2 macrophages were enriched in meningioma tissue. Coculture with meningioma cells induced the M2 polarization of macrophages. We also found that M2-MDEs were able to significantly promote cell proliferation, cell migration, cell invasion, and tumorigenesis in meningiomas. Bioinformatic analysis suggested that the TGF-β pathway was activated in meningioma cells treated with M2-MDEs. Functional experiments demonstrated that blocking the TGF-β signaling pathway could effectively reverse the tumor-promotive effects mediated by M2-MDEs. Conclusions. Overall, our study showed that M2-MDEs promoted meningioma development and invasion by activating the TGF-β signaling pathway. Targeting exosome-mediated intercellular communication in the tumor microenvironment may be a novel therapeutic strategy for meningioma patients.

The Role of Cancer Stem Cell-Derived Exosomes in Cancer Progression

Cancer stem cells (CSCs) represent a small portion of tumor cells with self-renewal ability in tumor tissues and are a key factor in tumor resistance, recurrence, and metastasis. CSCs produce a large number of exosomes through various mechanisms, such as paracrine and autocrine signaling. Studies have shown that CSC-derived exosomes (CSC-Exos) carry a variety of gene mutations and specific epigenetic modifications indicative of unique cell phenotypes and metabolic pathways, enabling exchange of information in the tumor microenvironment (TME) to promote tumor invasion and metastasis. In addition, CSC-Exos carry a variety of metabolites, especially proteins and miRNAs, which can activate signaling pathways to further promote tumor development. CSC-Exos have dual effects on cancer development. Due to advances in liquid biopsy technology for early cancer detection, CSCs-Exos may become an important tool for early cancer diagnosis and therapeutic drug delivery. In this article, we will review how CSC-Exos exert the above effects based on the above two aspects and explore their mechanism of action.