Cancer derived exosomes induce macrophages immunosuppressive polarization to promote bladder cancer progression

The interplay between the tumor microenvironment and tumor-derived small extracellular vesicles in cancer development and therapeutic response

The tumor microenvironment (TME) plays an essential role in tumor cell survival by profoundly influencing their proliferation, metastasis, immune evasion, and resistance to treatment. Extracellular vesicles (EVs) are small particles released by all cell types and often reflect the state of their parental cells and modulate other cells' functions through the various cargo they transport. Tumor-derived small EVs (TDSEVs) can transport specific proteins, nucleic acids and lipids tailored to propagate tumor signals and establish a favorable TME. Thus, the TME's biological characteristics can affect TDSEV heterogeneity, and this interplay can amplify tumor growth, dissemination, and resistance to therapy. This review discusses the interplay between TME and TDSEVs based on their biological characteristics and summarizes strategies for targeting cancer cells. Additionally, it reviews the current issues and challenges in this field to offer fresh insights into comprehending tumor development mechanisms and exploring innovative clinical applications.

Effect of tumor-derived extracellular vesicle-shuttled lncRNA MALAT1 on proliferation, invasion and metastasis of triple-negative breast cancer by regulating macrophage M2 polarization via the POSTN/Hippo/YAP axis

OBJECTIVES

Triple-negative breast cancer (TNBC) is the deadliest subtype of breast cancer (BC). Tumor-derived extracellular vesicles (EVs) trigger tumor progression by promoting M2 polarization. Some lncRNAs can be encapsulated into EVs for intercellular communication. Herein, we investigated the mechanism of TNBC-derived EV-shuttled lncRNA MALAT1 on macrophage polarization/tumorigenesis.

METHODS

BC-associated targeted EV-derived lncRNAs were screened. Tumor tissues/tissues adjacent to cancer of TNBC patients, and blood samples of all subjects were collected. MALAT1/POSTN mRNA levels in tumor tissues/tissues adjacent to cancer, and MALAT1 expression in EVs and its correlation with TNBC patient overall survival were assessed by RT-qPCR/Kaplan-Meier survival analysis/log-rank test. TNBC patient M2 infiltration was detected by flow cytometry. MALAT1/POSTN levels in EVs/macrophages were regulated by transfection. Hippo/YAP activation was determined by Western blot. Nude mouse xenograft model was established and metastasis was detected by H&E staining.

RESULTS

MALAT1/POSTN were up-regulated and correlated with M2 infiltration/poor prognosis in TNBC patients. TNBC-derived EVs induced M2 polarization. MALAT1 was highly expressed in TNBC-derived EVs and could be transferred to macrophages via EVs to induce M2 polarization. POSTN overexpression diminished the inhibitory effect of MALAT1 knockdown on M2 markers. EVs activated the Hippo/YAP pathway in macrophages. The Hippo/YAP pathway inhibition abrogated the effect of POSTN overexpression on M2 marker expression. TNBC-EV-derived MALAT1 facilitated M2 polarization, and thus promoting occurrence and metastasis of TNBC in vitro and in vivo.

CONCLUSIONS

TNBC-EV-derived MALAT1 activated the Hippo/YAP axis by up-regulating POSTN, thereby inducing M2 polarization to promote TNBC occurrence and metastasis in vivo.

Inhibition of STAT3: A promising approach to enhancing the efficacy of chemotherapy in medulloblastoma

Medulloblastoma is a type of brain cancer that primarily affects children. While chemotherapy has been shown to be effective in treating medulloblastoma, the development of chemotherapy resistance remains a challenge. One potential therapeutic approach is to selectively inhibit the inducible transcription factor called STAT3, which is known to play a crucial role in the survival and growth of tumor cells. The activation of STAT3 has been linked to the growth and progression of various cancers, including medulloblastoma. Inhibition of STAT3 has been shown to sensitize medulloblastoma cells to chemotherapy, leading to improved treatment outcomes. Different approaches to STAT3 inhibition have been developed, including small-molecule inhibitors and RNA interference. Preclinical studies have shown the efficacy of STAT3 inhibitors in medulloblastoma, and clinical trials are currently ongoing to evaluate their safety and effectiveness in patients with various solid tumors, including medulloblastoma. In addition, researchers are also exploring ways to optimize the use of STAT3 inhibitors in combination with chemotherapy and identify biomarkers that can predict treatment that will help to develop personalized treatment strategies. This review highlights the potential of selective inhibition of STAT3 as a novel approach for the treatment of medulloblastoma and suggests that further research into the development of STAT3 inhibitors could lead to improved outcomes for patients with aggressive cancer.

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, β-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

Identification of macrophage-related genes in bladder cancer patients using single-cell sequencing and construction of a prognostic model

Single-cell sequencing is an emerging technology that can effectively identify cell types in tumors. In the tumor microenvironment of bladder cancer, macrophages play a crucial role in invasion and immune escape. This study aimed to assess the expression of macrophage-related genes (MRGs) in the tumor microenvironment of bladder cancer patients and construct a prognostic model based on MRGs using bioinformatics methods.

METHODS

Single-cell sequencing data from bladder cancer patients was downloaded from the GEO. After quality control and cell type identification, macrophages in the samples were extracted for re-clustering. Feature genes were then identified, and MRGs were assessed. Genetic data from TCGA database bladder cancer patients was also downloaded and organized. The intersection of MRGs and the TCGA gene set was determined. Clinical information was connected with this intersection, and the data was divided into training and validation sets. The training set was used for model construction and the validation set for model verification. A prognostic model based on MRGs was built using the LASSO algorithm and Cox regression. Patients were divided into high-risk and low-risk groups based on their prognostic features, and survival information in the training and validation sets was observed. The predictive ability of the model was assessed using a ROC curve, followed by a calibration plot to predict 1-, 3-, and 5-year survival rates.

RESULTS

Four cell types were identified, and after extracting macrophages, three cell subgroups were clustered, resulting in 1,078 feature genes. The top 100 feature genes from each macrophage subgroup were extracted and intersected with TCGA expressed genes to construct the model. A risk prediction model composed of CD74, METRN, PTPRR, and CDC42EP5 was obtained. The survival and ROC curves showed that this model had good predictive ability. A calibration curve also demonstrated good prognostic ability for patients.

CONCLUSION

This study, based on single-cell data, TCGA data, and clinical information, constructed an MRG-based prognostic model for bladder cancer using multi-omics methods. This model has good accuracy and reliability in predicting the survival and prognosis of patients with bladder cancer, providing a reference for understanding the interaction between MRGs and bladder cancer.

Engineered biological nanoparticles as nanotherapeutics for tumor immunomodulation

Biological nanoparticles, or bionanoparticles, are small molecules manufactured in living systems with complex production and assembly machinery. The products of the assembly systems can be further engineered to generate functionalities for specific purposes. These bionanoparticles have demonstrated advantages such as immune system evasion, minimal toxicity, biocompatibility, and biological clearance. Hence, bionanoparticles are considered the new paradigm in nanoscience research for fabricating safe and effective nanoformulations for therapeutic purposes. Harnessing the power of the immune system to recognize and eradicate malignancies is a viable strategy to achieve better therapeutic outcomes with long-term protection from disease recurrence. However, cancerous tissues have evolved to become invisible to immune recognition and to transform the tumor microenvironment into an immunosuppressive dwelling, thwarting the immune defense systems and creating a hospitable atmosphere for cancer growth and progression. Thus, it is pertinent that efforts in fabricating nanoformulations for immunomodulation are mindful of the tumor-induced immune aberrations that could render cancer nanotherapy inoperable. This review systematically categorizes the immunosuppression mechanisms, the regulatory immunosuppressive cellular players, and critical suppressive molecules currently targeted as breakthrough therapies in the clinic. Finally, this review will summarize the engineering strategies for affording immune moderating functions to bionanoparticles that tip the tumor microenvironment (TME) balance toward cancer elimination, a field still in the nascent stage.

Potential molecular biomarkers for the diagnosis and prognosis of bladder cancer

Bladder cancer (BC) is a common malignant tumor of urinary system, which can be divided into muscle-invasive BC (MIBC) and nonmuscle-invasive BC (NMIBC). The number of BC patients has been gradually increasing currently. At present, bladder tumours are diagnosed and followed-up using a combination of cystoscopic examination, cytology and histology. However, the detection of early grade tumors, which is much easier to treat effectively than advanced stage disease, is still insufficient. It frequently recurs and can progress when not expeditiously diagnosed and monitored following initial therapy for NMIBC. Treatment strategies are totally different for different stage diseases. Therefore, it is of great practical significance to study new biomarkers for diagnosis and prognosis. In this review, we summarize the current state of biomarker development in BC diagnosis and prognosis prediction. We retrospectively analyse eight diagnostic biomarkers and eight prognostic biomarkers, in which CK, P53, PPARγ, PTEN and ncRNA are emphasized for discussion. Eight molecular subtype systems are also identified. Clinical translation of biomarkers for diagnosis, prognosis, monitoring and treatment will hopefully improve outcomes for patients. These potential biomarkers provide an opportunity to diagnose tumors earlier and with greater accuracy, and help identify those patients most at risk of disease recurrence.

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.

Exosomes-Promising Carriers for Regulatory Therapy in Oncology

Extracellular vesicles (EVs), including exosomes and microvesicles, together with apoptotic bodies form a diverse group of nanoparticles that play a crucial role in intercellular communication, participate in numerous physiological and pathological processes. In the context of cancer, they can allow the transfer of bioactive molecules and genetic material between cancer cells and the surrounding stromal cells, thus promoting such processes as angiogenesis, metastasis, and immune evasion. In this article, we review recent advances in understanding how EVs, especially exosomes, influence tumor progression and modulation of the microenvironment. The key mechanisms include exosomes inducing the epithelial-mesenchymal transition, polarizing macrophages toward protumoral phenotypes, and suppressing antitumor immunity. The therapeutic potential of engineered exosomes is highlighted, including their loading with drugs, RNA therapeutics, or tumor antigens to alter the tumor microenvironment. Current techniques for their isolation, characterization, and engineering are discussed. Ongoing challenges include improving exosome loading efficiency, optimizing biodistribution, and enhancing selective cell targeting. Overall, exosomes present promising opportunities to understand tumorigenesis and develop more targeted diagnostic and therapeutic strategies by exploiting the natural intercellular communication networks in tumors. In the context of oncology, regulatory therapy provides the possibility of reproducing the original conditions that are unfavorable for the existence of the cancer process and may thus be a feasible alternative to population treatments. We also review current access to the technology enabling regulatory intervention in the cancer process using exosomes.

[Efficacy of combined treatment with pirfenidone and PD-L1 inhibitor in mice bearing ectopic bladder cancer xenograft]

OBJECTIVE

To assess the efficacy of pirfenidone combined with PD-L1 inhibitor for treatment of bladder cancer in a mouse model and its effect on tumor immune microenvironment modulation.

METHODS

Forty C57BL/6 mouse models bearing ectopic human bladder cancer xenografts were randomized into control group, PD-L1 inhibitor group, pirfenidone group and combined treatment group (n=10). After successful modeling, PD-L1 inhibitor treatment was administered via intraperitoneal injection at 12.5 mg/kg every 3 days, and oral pirfenidone (500 mg/kg) was given on a daily basis. The survival rate of the mice and tumor growth rate were compared among the 4 groups. The expressions of CD3, CD8, CD45, E-cadherin and N-cadherin in the tumor tissues were detected with immunohistochemistry after the 21-day treatment, and bone marrow-derived suppressor cells (MDSCs) were observed with immunofluorescence staining; serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen (BUN), creatinine (CRE) and lactate dehydrogenase (LDH-L) were analyzed using an automated biochemical analyzer.

RESULTS

Treatment with PD-L1 inhibitor and pirfenidone alone both significantly decreased tumor growth rate and tumor volume at 21 days (P < 0.05), but the combined treatment produced an obviously stronger inhibitory effect (P < 0.05). PD-L1 inhibitor and pirfenidone alone significantly increased E- cadherin expression and decreased N-cadherin expression in the tumor tissue (P < 0.05). The two treatments both significantly increased the percentage of CD3+, CD8 and CD45+ T cells and decreased the percentage of Ly-6G+CD11b+MDSCs in the tumor tissue, and these changes were more obvious in the combined treatment group (P < 0.05). No significant differences were found in serum ALT, AST, BUN, CRE or LDH-L levels among the 4 groups (P>0.05).

CONCLUSION

Combined treatment with pirfenidone and PD-L1 inhibitor significantly inhibits the progression of bladder cancer in mice possibly by regulating tumor immune microenvironment and inhibiting epithelial-mesenchymal transition of the tumor cells.

Inhibition of circulating exosomes release with GW4869 mitigates severe acute pancreatitis-stimulated intestinal barrier damage through suppressing NLRP3 inflammasome-mediated pyroptosis

Intestinal barrier dysfunction frequently occurs as a complication in cases of severe acute pancreatitis (SAP); however, no effective therapeutic methods are available because the precise mechanism remains obscure. Recent research has elucidated the role of circulating exosomes in the progression of SAP. Therefore, the present study explored whether inhibiting circulating exosomes release would improve intestinal barrier injury triggered via SAP and investigated the possible underlying mechanism. In vivo, we found that circulating exosomes release exhibited a considerable increase in SAP rats than in SO rats, and GW4869, a suppressor of exosomes release, significantly decreased exosomes release in SAP rats. We also observed that GW4869 suppressed NLRP3 inflammasome-mediated pyroptosis within the intestine and alleviated intestinal barrier injury within SAP. Moreover, the inflammatory response and remote organ (kidney and lung) injury associated with SAP improved after GW4869 treatment. In vitro, we confirmed that depletion of exosomes with GW4869 could partially abolish the destructive effects of SAP rat plasma on the viability and barrier function of IEC-6 cells. In summary, our findings show that the suppression of the release of circulating exosomes effectively inhibits the process of pyroptosis mediated by the NOD-like receptor protein 3 (NLRP3) inflammasome and, therefore, mitigates intestinal barrier dysfunction in SAP, suggesting that circulating exosomes may be a potential target for treating SAP.

Cancer Pathways Targeted by Berberine: Role of microRNAs

Cancer is a complex and heterogeneous malignant disease. Due to its multifactorial nature, including progressive changes in genetic, epigenetic, transcript, and protein levels, conventional therapeutics fail to save cancer patients. Evidence indicates that dysregulation of microRNA (miRNA) expression plays a crucial role in tumorigenesis, metastasis, cell proliferation, differentiation, metabolism, and signaling pathways. Moreover, miRNAs can be used as diagnostic and prognostic markers and therapeutic targets in cancer. Berberine, a naturally occurring plant alkaloid, has a wide spectrum of biological activities in different types of cancers. Inhibition of cell proliferation, metastasis, migration, invasion, and angiogenesis, as well as induction of cell cycle arrest and apoptosis in cancer cells, is reported by berberine. Recent studies suggested that berberine regulates many oncogenic and tumor suppressor miRNAs implicated in different phases of cancer. This review discussed how berberine inhibits cancer growth and propagation and regulates miRNAs in cancer cells. And how berberine-mediated miRNA regulation changes the landscape of transcripts and proteins that promote or suppress cancer progression. Overall, the underlying molecular pathways altered by berberine and miRNA influencing the tumor pathophysiology will enhance our understanding to combat the malignancy.

Tumor-related exosomal circ_0001715 promotes lung adenocarcinoma cell proliferation and metastasis via enhancing M2 macrophage polarization by regulating triggering receptor expressed on myeloid cells-2

BACKGROUND

Circular RNAs (circRNAs) have been shown to mediate tumor-associated macrophages (TAMs) to regulate the development of many cancers, including lung adenocarcinoma (LUAD). However, whether circ_0001715 regulates LUAD progression by mediating TAMs polarization remains uncertain.

METHODS

Monocytes (THP-1) were treated with PMA to induce M0 macrophages. M0 macrophages were incubated with LUAD cells-derived exosomes and then cocultured with LUAD cells. The levels of circ_0001715, M2 macrophage markers, microRNA (miR)-205-5p, and triggering receptor expressed on myeloid cells-2 (TREM2) were examined using quantitative real-time PCR. Flow cytometry was performed to assess M2 macrophage surface marker CD206. Cell proliferation, migration and invasion were determined using cell counting kit 8, EdU, colony formation and transwell assays. Dual-luciferase reporter assay was used to investigate the interactions between miR-205-5p and circ_0001715 or TREM2.

RESULTS

Circ_0001715 knockdown inhibited M2 macrophage polarization and its overexpression had an opposite effect. After M0 macrophages transfected with si-circ_0001715 were cocultured with LUAD cells, the proliferation and metastasis of LUAD cells were markedly reduced. Exosomes transferred circ_0001715 between M0 macrophages and LUAD cells. Exosomal circ_0001715 promoted M2 macrophage polarization to increase LUAD cell proliferation and metastasis. In terms of mechanism, circ_0001715 sponged miR-205-5p to positively regulate TREM2. TREM2 upregulation also could promote LUAD cell proliferation and metastasis via increasing M2 macrophage polarization. In addition, TREM2 knockdown reversed the effect of exosomal circ_0001715 on M2 macrophage polarization and LUAD cell progression.

CONCLUSION

Exosomal circ_0001715 led to LUAD cell proliferation and metastasis by promoting M2 macrophage polarization via the miR-205-5p/TREM2 axis.

Biological, pathological, and multifaceted therapeutic functions of exosomes to target cancer

Exosomes, small tiny vesicle contains a large number of intracellular particles that employ to cause various diseases and prevent several pathological events as well in the human body. It is considered a "double-edged sword", and depending on its biological source, the action of exosomes varies under physiological conditions. Also, the isolation and characterization of the exosomes should be performed accurately and the methodology also will vary depending on the exosome source. Moreover, the uptake of exosomes from the recipients' cells is a vital and initial step for all the physiological actions. There are different mechanisms present in the exosomes' cellular uptake to deliver their cargo to acceptor cells. Once the exosomal uptake takes place, it releases the intracellular particles that leads to activate the physiological response. Even though exosomes have lavish functions, there are some challenges associated with every step of their preparation to bring potential therapeutic efficacy. So, overcoming the pitfalls would give a desired quantity of exosomes with high purity.

Advances in the study of macrophage polarization in inflammatory immune skin diseases

When exposed to various microenvironmental stimuli, macrophages are highly plastic and primarily polarized into the pro-inflammatory M1-type and the anti-inflammatory M2-type, both of which perform almost entirely opposing functions. Due to this characteristic, macrophages perform different functions at different stages of immunity and inflammation. Inflammatory immune skin diseases usually show an imbalance in the M1/M2 macrophage ratio, and altering the macrophage polarization phenotype can either make the symptoms worse or better. Therefore, this review presents the mechanisms of macrophage polarization, inflammation-related signaling pathways (JAK/STAT, NF-κB, and PI3K/Akt), and the role of both in inflammatory immune skin diseases (psoriasis, AD, SLE, BD, etc.) to provide new directions for basic and clinical research of related diseases.

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 and particles as mediators of long-range communication in cancer: connecting biological function to clinical applications

Over the past decade, extracellular vesicles and particles (EVPs) have emerged as critical mediators of intercellular communication, participating in numerous physiological and pathological processes. In the context of cancer, EVPs exert local effects, such as increased invasiveness, motility, and reprogramming of tumor stroma, as well as systemic effects, including pre-metastatic niche formation, determining organotropism, promoting metastasis and altering the homeostasis of various organs and systems, such as the liver, muscle, and circulatory system. This review provides an overview of the critical advances in EVP research during the past decade, highlighting the heterogeneity of EVPs, their roles in intercellular communication, cancer progression, and metastasis. Moreover, the clinical potential of systemic EVPs as useful cancer biomarkers and therapeutic agents is explored. Last but not least, the progress in EVP analysis technologies that have facilitated these discoveries is discussed, which may further propel EVP research in the future.

Comparison of immunotherapy mediated by apoptotic bodies, microvesicles and exosomes: apoptotic bodies' unique anti-inflammatory potential

Immunotherapy, including immunostimulation and immunosuppression, has seen significant development in the last 10 years. Immunostimulation has been verified as effective in anti-cancer treatment, while immunosuppression is used in the treatment of autoimmune disease and inflammation. Currently, with the update of newly-invented simplified isolation methods and the findings of potent triggered immune responses, extracellular vesicle-based immunotherapy is very eye-catching. However, the research on three main types of extracellular vesicles, exosomes, microvesicles and apoptotic bodies, needs to be more balanced. These three subtypes share a certain level of similarity, and at the same time, they have their own properties caused by the different methods of biogensis. Herein, we summarized respectively the status of immunotherapy based on each kind of vesicle and discuss the possible involved mechanisms. In conclusion, we highlighted that the effect of the apoptotic body is clear and strong. Apoptotic bodies have an excellent potential in immunosuppressive and anti-inflammatory therapies .

Exosome-mediated crosstalk between tumor cells and innate immune cells: implications for cancer progression and therapeutic strategies

The increasing number of cancer-associated deaths despite the substantial improvement in diagnosis and treatment has sparked discussions on the need for novel biomarkers and therapeutic strategies for cancer. Exosomes have become crucial players in tumor development and progression, largely due to the diverse nature of their cargo content released to recipient cells. Importantly, exosome-mediated crosstalk between tumor and stromal cells is essential in reprogramming the tumor microenvironment to facilitate tumor progression. As a result, exosomes have gradually become a marker for the early diagnosis of many diseases and an important tool in drug delivery systems. However, the precise mechanisms by which exosomes participate in tumor progression remain elusive, multifaceted, and a double-edged sword, thus requiring further clarification. The available evidence suggests that exosomes can facilitate communication between innate immune cells and tumor cells to either support or inhibit tumor progression. Herein, this review focused on exosome-mediated intercellular communication between tumor cells and macrophages, neutrophils, mast cells, monocytes, dendritic cells, and natural killer cells. Specifically, how such intercellular communication affects tumor progression has been described. It has also been discussed that, depending on their cargo, exosomes can suppress or promote tumor cell progression. In addition, the potential application of exosomes and strategies to target exosomes in cancer treatment has been comprehensively discussed.

Extracellular vesicles as next generation immunotherapeutics

Extracellular vesicles (EVs) function as a mode of intercellular communication and molecular transfer to elicit diverse biological/functional response. Accumulating evidence has highlighted that EVs from immune, tumour, stromal cells and even bacteria and parasites mediate the communication of various immune cell types to dynamically regulate host immune response. EVs have an innate capacity to evade recognition, transport and transfer functional components to target cells, with subsequent removal by the immune system, where the immunological activities of EVs impact immunoregulation including modulation of antigen presentation and cross-dressing, immune activation, immune suppression, and immune surveillance, impacting the tumour immune microenvironment. In this review, we outline the recent progress of EVs in immunorecognition and therapeutic intervention in cancer, including vaccine and targeted drug delivery and summarise their utility towards clinical translation. We highlight the strategies where EVs (natural and engineered) are being employed as a therapeutic approach for immunogenicity, tumoricidal function, and vaccine development, termed immuno-EVs. With seminal studies providing significant progress in the sequential development of engineered EVs as therapeutic anti-tumour platforms, we now require direct assessment to tune and improve the efficacy of resulting immune responses - essential in their translation into the clinic. We believe such a review could strengthen our understanding of the progress in EV immunobiology and facilitate advances in engineering EVs for the development of novel EV-based immunotherapeutics as a platform for cancer treatment.

Extracellular Vesicles as Potential Bladder Cancer Biomarkers: Take It or Leave It?

Bladder cancer (BC) is the 10th most frequently diagnosed cancer worldwide. Although urine cytology and cystoscopy are current standards for BC diagnosis, both have limited sensitivity to detect low-grade and small tumors. Moreover, effective prognostic biomarkers are lacking. Extracellular vesicles (EVs) are lipidic particles that contain nucleic acids, proteins, and metabolites, which are released by cells into the extracellular space, being crucial effectors in intercellular communication. These particles have emerged as potential tools carrying biomarkers for either diagnosis or prognosis in liquid biopsies namely urine, plasma, and serum. Herein, we review the potential of liquid biopsies EVs’ cargo as BC diagnosis and prognosis biomarkers. Additionally, we address the emerging advantages and downsides of using EVs within this framework.

Gastric cancer-derived exosomes facilitate pulmonary metastasis by activating ERK-mediated immunosuppressive macrophage polarization

Gastric cancer (GC) with pulmonary metastasis is one of the deadliest diseases in the world; however, the underlying pathological mechanisms and potential therapeutic targets remain to be elucidated. As exosomes play indispensable roles in the formation of premetastatic niches (PMN) and cancer metastasis. Therefore, investigating the underlying mechanisms of exosome-mediated pulmonary metastasis of GC may shed new light on identifying novel therapeutic targets for GC treatment. GC-derived exosomes were isolated from the conditioned medium of mouse forestomach carcinoma (MFC) cell line. The effects of MFC-derived exosomes on pulmonary macrophage polarization were analyzed by reverse- transcription polymerase chain reaction and flow cytometry. Expression of PD-L1 and other proteins was evaluated by Western blot. Exosomal microRNAs (miRNAs) were analyzed by microarray. GC-derived exosomes (GC-exo) accumulated in high numbers in the lungs and were ingested by macrophages. The extracellular-signal-regulated kinase (ERK) signaling pathway was activated by GC-exo, inducing macrophage immunosuppressive-phenotype differentiation and increased PD-L1 expression. miRNA-sequencing identified 130 enriched miRNAs in GC-exo. Among the enriched miRNAs, miR-92a-3p plays a major role in activating ERK signaling via inhibition of PTEN expression. In addition, inhibiting ERK signaling with PD98059 significantly reduced the expression of PD-L1 in macrophages and, therefore, reversed the immunosuppressive PMN and inhibited the colonization of GC cells in the lungs. This study identified a novel mechanism of GC-exo mediated PD-L1 expression in lung macrophages that facilitates lung PMN formation and GC pulmonary metastasis, which also provided a potential therapeutic target for GC with pulmonary metastasis treatment.

Natural products targeting macrophages in tumor microenvironment are a source of potential antitumor agents

BACKGROUND

Macrophages are one of the major cell types in the immune system and are closely related to tumor development, which can be polarized into M1 type with anti-tumor activity or M2 type with pro-tumor activity. The infiltration of more macrophages into tumor predicts poorer prognosis due to their more exhibition of M2 phenotype under the influence of many factors in the tumor microenvironment (TME). Therefore, reverse of M2 macrophage polarization in TME is conducive to the suppression of tumor deterioration and understanding the influencing factors of macrophage polarization is helpful to provide new ideas for the subsequent targeting macrophages for tumor therapy.

PURPOSE

This review summarizes the effects of TME on macrophage polarization and natural products against M2 macrophage polarization, which may provide some directions for tumor therapy.

METHODS

The search of relevant literature was conducted using the PubMed, Science Direct, CNKI and Web of Science databases with the search terms "macrophage", "tumor microenvironment", "natural product" and "tumor".

RESULTS

The mutual transformation of M1 and M2 phenotypes in macrophages is influenced by many factors. Tumor cells affect the polarization of macrophages by regulating the expression of genes and proteins and the secretion of cytokines. The expression of some genes or proteins in macrophages is also related to their own polarization. Many natural products can reverse M2 polarization of macrophages which has been summarized in this review.

CONCLUSION

Regulation of macrophage polarization in TME can inhibit tumor development, and natural products have the potential to impede tumor development by regulating macrophage polarization.

Extracellular Vesicles (EVs) in Tumor Diagnosis and Therapy

In recent years, extracellular vesicles (EVs) have gained significant attention due to their tremendous potential for clinical applications. EVs play a crucial role in various aspects, including tumorigenesis, drug resistance, immune escape, and reconstruction of the tumor microenvironment. Despite the growing interest in EVs, many questions still need to be addressed before they can be practically applied in clinical settings. This paper aims to review EVs' isolation methods, structure research, the roles of EVs in tumorigenesis and their mechanisms in multiple types of tumors, their potential application in drug delivery, and the expectations for their future in clinical research.

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.

Ferroptosis-dependent breast cancer cell-derived exosomes inhibit migration and invasion of breast cancer cells by suppressing M2 macrophage polarization

Aim

Ferroptosis, a novel type of iron-dependent cell death, plays a vital role in breast cancer progression. However, the function of ferroptosis-induced cancer cell-derived exosomes in breast cancer remains unclear. In this study, we attempted to investigate the impact of breast cancer cells-derived exosomes induced by ferroptosis on the polarization of macrophages and the progression of breast cancer.

Methods

Erastin was used to induce ferroptosis and breast cancer cell-derived exosomes were identified by transmission electron microscopy. Western blot, quantitative reverse transcription PCR, immunofluorescence, flow cytometry, and ELISA were used to determine the role of exosomes in macrophage polarization. Transwell assays were used to detect breast cancer cell migration, and invasion.

Results

Our results showed that erastin promoted ferroptosis in breast cancer cells with increased Fe2+ level and ROS production. Breast cancer cell-derived exosomes induced by ferroptosis were successfully isolated and verified to be internalized by macrophages. In addition, ferroptosis-induced breast cancer cell-derived exosomes (Fe-exo) remarkably diminished M2 marker, Arg-1 expression. The ratio of CD206⁺ macrophages was significantly decreased after Fe-exo treatment. CD206 protein expression and Arg-1 level were dramatically reduced in M2 macrophages incubated by Fe-exo. Moreover, autophagy PCR array showed that the expression of 84 autophagy-related genes were altered after macrophages were incubated by Fe-exo. Furthermore, macrophages incubated by Fe-exo repressed the migration and invasion of breast cancer cells.

Conclusion

Ferroptosis-dependent cancer cell-derived exosomes inhibited M2 polarization of macrophages, which in turn inhibited migration and invasion of breast cancer cells. This study provides novel therapeutic strategies for patients with breast cancer.

Advances in the role of STAT3 in macrophage polarization

The physiological processes of cell growth, proliferation, differentiation, and apoptosis are closely related to STAT3, and it has been demonstrated that aberrant STAT3 expression has an impact on the onset and progression of a number of inflammatory immunological disorders, fibrotic diseases, and malignancies. In order to produce the necessary biological effects, macrophages (M0) can be polarized into pro-inflammatory (M1) and anti-inflammatory (M2) types in response to various microenvironmental stimuli. STAT3 signaling is involved in macrophage polarization, and the research of the effect of STAT3 on macrophage polarization has gained attention in recent years. In order to provide references for the treatment and investigation of disorders related to macrophage polarization, this review compiles the pertinent signaling pathways associated with STAT3 and macrophage polarization from many fundamental studies.

Aberrant hyperexpression of the RNA binding protein FMRP in tumors mediates immune evasion

Many human cancers manifest the capability to circumvent attack by the adaptive immune system. In this work, we identified a component of immune evasion that involves frequent up-regulation of fragile X mental retardation protein (FMRP) in solid tumors. FMRP represses immune attack, as revealed by cancer cells engineered to lack its expression. FMRP-deficient tumors were infiltrated by activated T cells that impaired tumor growth and enhanced survival in mice. Mechanistically, FMRP’s immunosuppression was multifactorial, involving repression of the chemoattractant C-C motif chemokine ligand 7 (CCL7) concomitant with up-regulation of three immunomodulators—interleukin-33 (IL-33), tumor-secreted protein S (PROS1), and extracellular vesicles. Gene signatures associate FMRP’s cancer network with poor prognosis and response to therapy in cancer patients. Collectively, FMRP is implicated as a regulator that orchestrates a multifaceted barrier to antitumor immune responses.

miR-aculous new avenues for cancer immunotherapy

The rising toll of cancer globally necessitates ingenuity in early detection and therapy. In the last decade, the utilization of immune signatures and immune-based therapies has made significant progress in the clinic; however, clinical standards leave many current and future patients without options. Non-coding RNAs, specifically microRNAs, have been explored in pre-clinical contexts with tremendous success. MicroRNAs play indispensable roles in programming the interactions between immune and cancer cells, many of which are current or potential immunotherapy targets. MicroRNAs mechanistically control a network of target genes that can alter immune and cancer cell biology. These insights provide us with opportunities and tools that may complement and improve immunotherapies. In this review, we discuss immune and cancer cell-derived miRNAs that regulate cancer immunity and examine miRNAs as an integral part of cancer diagnosis, classification, and therapy.

Biological Features of Extracellular Vesicles and Challenges

Extracellular vesicles (EVs) are vesicles with a lipid bilayer membrane on the outside, which are widely found in various body fluids and contain biological macromolecules such as DNA, RNA, lipids and proteins on the inside. EVs were once thought to be vesicles for the removal of waste materials, but are now known to be involved in a variety of pathophysiological processes in many diseases. This study examines the advantage of EVs and the challenges associated with their application. A more rational use of the advantageous properties of EVs such as composition specificity, specific targeting, circulatory stability, active penetration of biological barriers, high efficient drug delivery vehicles and anticancer vaccines, oxidative phosphorylation activity and enzymatic activity, and the resolution of shortcomings such as isolation and purification methods, storage conditions and pharmacokinetics and biodistribution patterns during drug delivery will facilitate the clinical application of EVs.

Mitochondrial DNA on Tumor-Associated Macrophages Polarization and Immunity

As the richest immune cells in most tumor microenvironments (TMEs), tumor-associated macrophages (TAMs) play an important role in tumor development and treatment sensitivity. The phenotypes and functions of TAMs vary according to their sources and tumor progression. Different TAM phenotypes display distinct behaviors in terms of tumor immunity and are regulated by intracellular and exogenous molecules. Additionally, dysfunctional and oxidatively stressed mitochondrial-derived mitochondrial DNA (mtDNA) plays an important role in remodeling the phenotypes and functions of TAMs. This article reviews the interactions between mtDNA and TAMs in the TME and further discusses the influence of their performance on tumor genesis and development.