EZH2 enhances expression of CCL5 to promote recruitment of macrophages and invasion in lung cancer

Role of the AKT signaling pathway in regulating tumor-associated macrophage polarization and in the tumor microenvironment: A review

Tumor-associated macrophages (TAMs) are present in and are important components of the tumor microenvironment (TME). TAMs differentiate into 2 functionally distinct morphologies, classically activated (M1)-type TAMs and alternatively activated (M2)-type TAMs, when stimulated by different cytokines. The 2 types of TAMs exhibit distinct properties and functions. M1 TAMs secrete high levels of pro-inflammatory and chemotactic factors, exerting proinflammatory, antitumor effects. Conversely, M2 TAMs alter the extracellular matrix, facilitate cellular immune escape, and stimulate tumor angiogenesis, thereby promoting anti-inflammatory responses and tumor growth. The ratio of M1 TAMs to M2 TAMs in the TME is closely related to the prognosis of the tumor. Tumor cells and other cells in the TME can regulate the polarization of TAMs and thus promote tumor progression through the secretion of various substances; however, polarized TAMs can also act on various cells in the TME through the secretion of exosomes, thus forming a positive feedback loop. Therefore, modulating the phenotype of TAMs in the TME or blocking the polarization of M2 TAMs might be a new approach for cancer treatment. However, the intracellular signaling pathways involved in the polarization of TAMs are poorly understood. The AKT signaling pathway is an important signaling pathway involved in the polarization, growth, proliferation, recruitment, and apoptosis of TAMs, as well as the action of TAMs on other cells within the TME. This paper reviews the AKT signaling pathway in the polarization of TAMs and the regulation of the TME and provides new ideas for tumor immunotherapy.

C-C motif chemokine ligand 5 contributes to radon exposure-induced lung injury by recruiting dendritic cells to activate effector T helper cells

Radon (222Rn) is a naturally occurring radioactive gas, ionizing radiation emitted by the radon induces oxidative stress and the up-regulation of inflammatory proteins, which may cause lung damage or cancer. However, the underlying pathogenesis remains to be determined. Effector T helper cells are key in mediating the host's protection and immune homeostasis. In this study we revealed that, accompanied by the activation of effector T helper cells, there is a significant increase in C-C motif chemokine ligand 5 (Ccl5) in the lung of mice after cumulative inhalation of radon at 3, 9, 21, 45, 90, and 180 working level months (WLM). In vitro experiments showed that Ccl5 attracts DC migration and promotes the activation of effector T helper cells in the Ccl5-DC and T cells co-culture model. Of particular interest, Ccl5 neutralization in vivo inhibited the migration of DC cells and the subsequent activation of effector T helper cells, which finally protected mice from radon-induced lung damage and inflammatory response. Ultimately, transcriptome sequencing and western blot analysis showed that Ccl5 activates the CCR5/PI3K/AKT/Nr4a1 pathway to increase the secretion of IL-12 and IFN-γ by DC cells, which then promotes the activation of effector T helper cells. Overall, these results indicate that Ccl5 significantly contributes to the progression of radon-induced lung damage by modulating DC to activate effector T helper cells.

Targeting EZH2 in Cancer: Mechanisms, Pathways, and Therapeutic Potential

Enhancer of zeste homolog 2 (EZH2) is a methyltransferase involved in cell cycle regulation, cell differentiation, and cell death and plays a role in modulating the immune response. Although it mainly functions by catalyzing the tri-methylation of H3 histone on K27 (H3K27), to inhibit the transcription of target genes, EZH2 can directly methylate several transcription factors or form complexes with them, regulating their functions. EZH2 expression/activity is often dysregulated in cancer, contributing to carcinogenesis and immune escape, thereby representing an important target in anti-cancer therapy. This review summarizes some of the mechanisms through which EZH2 regulates the expression and function of tumor suppressor genes and oncogenic molecules such as STAT3, mutant p53, and c-Myc and how it modulates the anti-cancer immune response. The influence of posttranslational modifications on EZH2 activity and stability and the possible strategies leading to its inhibition are also reviewed.

IC Regimen: Delaying Resistance to Lorlatinib in ALK Driven Cancers by Adding Repurposed Itraconazole and Cilostazol

Lorlatinib is a pharmaceutical ALK kinase inhibitor used to treat ALK driven non-small cell lung cancers. This paper analyses the intersection of past published data on the physiological consequences of two unrelated drugs from general medical practice-itraconazole and cilostazol-with the pathophysiology of ALK positive non-small cell lung cancer. A conclusion from that data analysis is that adding itraconazole and cilostazol may make lorlatinib more effective. Itraconazole, although marketed worldwide as a generic antifungal drug, also inhibits Hedgehog signaling, Wnt signaling, hepatic CYP3A4, and the p-gp efflux pump. Cilostazol, marketed worldwide as a generic thrombosis preventative drug, acts by inhibiting phosphodiesterase 3, and, by so doing, lowers platelets' adhesion, thereby partially depriving malignant cells of the many tumor trophic growth factors supplied by platelets. Itraconazole may enhance lorlatinib effectiveness by (i) reducing or stopping a Hedgehog-ALK amplifying feedback loop, by (ii) increasing lorlatinib's brain levels by p-gp inhibition, and by (iii) inhibiting growth drive from Wnt signaling. Cilostazol, surprisingly, carries minimal bleeding risk, lower than that of aspirin. Risk/benefit assessment of the combination of metastatic ALK positive lung cancer being a low-survival disease with the predicted safety of itraconazole-cilostazol augmentation of lorlatinib favors a trial of this drug trio in ALK positive lung cancer.

Immunotherapies Targeting Tumor-Associated Macrophages (TAMs) in Cancer

Tumor-associated macrophages (TAMs) are one of the most plentiful immune compositions in the tumor microenvironment, which are further divided into anti-tumor M1 subtype and pro-tumor M2 subtype. Recent findings found that TAMs play a vital function in the regulation and progression of tumorigenesis. Moreover, TAMs promote tumor vascularization, and support the survival of tumor cells, causing an impact on tumor growth and patient prognosis. Numerous studies show that reducing the density of TAMs, or modulating the polarization of TAMs, can inhibit tumor growth, indicating that TAMs are a promising target for tumor immunotherapy. Recently, clinical trials have found that treatments targeting TAMs have achieved encouraging results, and the U.S. Food and Drug Administration has approved a number of drugs for use in cancer treatment. In this review, we summarize the origin, polarization, and function of TAMs, and emphasize the therapeutic strategies targeting TAMs in cancer treatment in clinical studies and scientific research, which demonstrate a broad prospect of TAMs-targeted therapies in tumor immunotherapy.

EZH2-Myc Hallmark in Oncovirus/Cytomegalovirus Infections and Cytomegalovirus' Resemblance to Oncoviruses

Approximately 15-20% of global cancer cases are attributed to virus infections. Oncoviruses employ various molecular strategies to enhance replication and persistence. Human cytomegalovirus (HCMV), acting as an initiator or promoter, enables immune evasion, supporting tumor growth. HCMV activates pro-oncogenic pathways within infected cells and direct cellular transformation. Thus, HCMV demonstrates characteristics reminiscent of oncoviruses. Cumulative evidence emphasizes the crucial roles of EZH2 and Myc in oncogenesis and stemness. EZH2 and Myc, pivotal regulators of cellular processes, gain significance in the context of oncoviruses and HCMV infections. This axis becomes a central focus for comprehending the mechanisms driving virus-induced oncogenesis. Elevated EZH2 expression is evident in various cancers, making it a prospective target for cancer therapy. On the other hand, Myc, deregulated in over 50% of human cancers, serves as a potent transcription factor governing cellular processes and contributing to tumorigenesis; Myc activates EZH2 expression and induces global gene expression. The Myc/EZH2 axis plays a critical role in promoting tumor growth in oncoviruses. Considering that HCMV has been shown to manipulate the Myc/EZH2 axis, there is emerging evidence suggesting that HCMV could be regarded as a potential oncovirus due to its ability to exploit this critical pathway implicated in tumorigenesis.

Exploring the therapeutic potential of targeting polycomb repressive complex 2 in lung cancer

The pathogenesis of lung cancer (LC) is a multifaceted process that is influenced by a variety of factors. Alongside genetic mutations and environmental influences, there is increasing evidence that epigenetic mechanisms play a significant role in the development and progression of LC. The Polycomb repressive complex 2 (PRC2), composed of EZH1/2, SUZ12, and EED, is an epigenetic silencer that controls the expression of target genes and is crucial for cell identity in multicellular organisms. Abnormal expression of PRC2 has been shown to contribute to the progression of LC through several pathways. Although targeted inhibition of EZH2 has demonstrated potential in delaying the progression of LC and improving chemotherapy sensitivity, the effectiveness of enzymatic inhibitors of PRC2 in LC is limited, and a more comprehensive understanding of PRC2's role is necessary. This paper reviews the core subunits of PRC2 and their interactions, and outlines the mechanisms of aberrant PRC2 expression in cancer and its role in tumor immunity. We also summarize the important role of PRC2 in regulating biological behaviors such as epithelial mesenchymal transition, invasive metastasis, apoptosis, cell cycle regulation, autophagy, and PRC2-mediated resistance to LC chemotherapeutic agents in LC cells. Lastly, we explored the latest breakthroughs in the research and evaluation of medications that target PRC2, as well as the latest findings from clinical studies investigating the efficacy of these drugs in the treatment of various human cancers.

Alveolar macrophages in lung cancer: opportunities challenges

Alveolar macrophages (AMs) are critical components of the innate defense mechanism in the lung. Nestled tightly within the alveoli, AMs, derived from the yolk-sac or bone marrow, can phagocytose foreign particles, defend the host against pathogens, recycle surfactant, and promptly respond to inhaled noxious stimuli. The behavior of AMs is tightly dependent on the environmental cues whereby infection, chronic inflammation, and associated metabolic changes can repolarize their effector functions in the lungs. Several factors within the tumor microenvironment can re-educate AMs, resulting in tumor growth, and reducing immune checkpoint inhibitors (ICIs) efficacy in patients treated for non-small cell lung cancer (NSCLC). The plasticity of AMs and their critical function in altering tumor responses to ICIs make them a desirable target in lung cancer treatment. New strategies have been developed to target AMs in solid tumors reprograming their suppressive function and boosting the efficacy of ICIs. Here, we review the phenotypic and functional changes in AMs in response to sterile inflammation and in NSCLC that could be critical in tumor growth and metastasis. Opportunities in altering AMs' function include harnessing their potential function in trained immunity, a concept borrowed from memory response to infections, which could be explored therapeutically in managing lung cancer treatment.

Therapies Targeting Immune Cells in Tumor Microenvironment for Non-Small Cell Lung Cancer

The tumor microenvironment (TME) plays critical roles in immune modulation and tumor malignancies in the process of cancer development. Immune cells constitute a significant component of the TME and influence the migration and metastasis of tumor cells. Recently, a number of therapeutic approaches targeting immune cells have proven promising and have already been used to treat different types of cancer. In particular, PD-1 and PD-L1 inhibitors have been used in the first-line setting in non-small cell lung cancer (NSCLC) with PD-L1 expression ≥1%, as approved by the FDA. In this review, we provide an introduction to the immune cells in the TME and their efficacies, and then we discuss current immunotherapies in NSCLC and scientific research progress in this field.

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.

Modulation of EZH2 Activity Induces an Antitumoral Effect and Cell Redifferentiation in Anaplastic Thyroid Cancer

Anaplastic thyroid cancer (ATC) is a rare and lethal form of thyroid cancer that requires urgent investigation of new molecular targets involved in its aggressive biology. In this context, the overactivation of Polycomb Repressive Complex 2/EZH2, which induces chromatin compaction, is frequently observed in aggressive solid tumors, making the EZH2 methyltransferase a potential target for treatment. However, the deregulation of chromatin accessibility is yet not fully investigated in thyroid cancer. In this study, EZH2 expression was modulated by CRISPR/Cas9-mediated gene editing and pharmacologically inhibited with EZH2 inhibitor EPZ6438 alone or in combination with the MAPK inhibitor U0126. The results showed that CRISPR/Cas9-induced EZH2 gene editing reduced cell growth, migration and invasion in vitro and resulted in a 90% reduction in tumor growth when EZH2-edited cells were injected into an immunocompromised mouse model. Immunohistochemistry analysis of the tumors revealed reduced tumor cell proliferation and less recruitment of cancer-associated fibroblasts in the EZH2-edited tumors compared to the control tumors. Moreover, EZH2 inhibition induced thyroid-differentiation genes' expression and mesenchymal-to-epithelial transition (MET) in ATC cells. Thus, this study shows that targeting EZH2 could be a promising neoadjuvant treatment for ATC, as it promotes antitumoral effects in vitro and in vivo and induces cell differentiation.

Macrophage CD5L is a target for cancer immunotherapy

BACKGROUND

Reprogramming of immunosuppressive tumor-associated macrophages (TAMs) presents an attractive therapeutic strategy in cancer. The aim of this study was to explore the role of macrophage CD5L protein in TAM activity and assess its potential as a therapeutic target.

METHODS

Monoclonal antibodies (mAbs) against recombinant CD5L were raised by subcutaneous immunization of BALB/c mice. Peripheral blood monocytes were isolated from healthy donors and stimulated with IFN/LPS, IL4, IL10, and conditioned medium (CM) from different cancer cell lines in the presence of anti-CD5L mAb or controls. Subsequently, phenotypic markers, including CD5L, were quantified by flow cytometry, IF and RT-qPCR. Macrophage CD5L protein expression was studied in 55 human papillary lung adenocarcinoma (PAC) samples by IHC and IF. Anti-CD5L mAb and isotype control were administered intraperitoneally into a syngeneic Lewis Lung Carcinoma mouse model and tumor growth was measured. Tumor microenvironment (TME) changes were determined by flow cytometry, IHC, IF, Luminex, RNAseq and RT-qPCR.

FINDINGS

Cancer cell lines CM induced an immunosuppressive phenotype (increase in CD163, CD206, MERTK, VEGF and CD5L) in cultured macrophages. Accordingly, high TAM expression of CD5L in PAC was associated with poor patient outcome (Log-rank (Mantel-Cox) test p = 0.02). We raised a new anti-CD5L mAb that blocked the immunosuppressive phenotype of macrophages in vitro. Its administration in vivo inhibited tumor progression of lung cancer by altering the intratumoral myeloid cell population profile and CD4⁺ T-cell exhaustion phenotype, thereby significantly modifying the TME and increasing the inflammatory milieu.

INTERPRETATION

CD5L protein plays a key function in modulating the activity of macrophages and their interactions within the TME, which supports its role as a therapeutic target in cancer immunotherapy.

FUNDING

For a full list of funding bodies, please see the Acknowledgements.

The pharmacological and biological importance of EZH2 signaling in lung cancer

Up to 18% of cancer-related deaths worldwide are attributed to lung tumor and global burden of this type of cancer is ascending. Different factors are responsible for development of lung cancer such as smoking, environmental factors and genetic mutations. EZH2 is a vital protein with catalytic activity and belongs to PCR2 family. EZH2 has been implicated in regulating gene expression by binding to promoter of targets. The importance of EZH2 in lung cancer is discussed in current manuscript. Activation of EZH2 significantly elevates the proliferation rate of lung cancer. Furthermore, metastasis and associated molecular mechanisms including EMT undergo activation by EZH2 in enhancing the lung cancer progression. The response of lung cancer to therapy can be significantly diminished due to EZH2 upregulation. Since EZH2 increases tumor progression, anti-cancer agents suppressing its expression reduce malignancy. In spite of significant effort in understanding modulatory function of EZH2 on other pathways, it appears that EZH2 can be also regulated and controlled by other factors that are described in current review. Therefore, translating current findings to clinic can improve treatment and management of lung cancer patients.

Multiomics characteristics and immunotherapeutic potential of EZH2 in pan-cancer

Enhancer of zeste homolog 2 (EZH2) is a significant epigenetic regulator that plays a critical role in the development and progression of cancer. However, the multiomics features and immunological effects of EZH2 in pan-cancer remain unclear. Transcriptome and clinical raw data of pan-cancer samples were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and subsequent data analyses were conducted by using R software (version 4.1.0). Furthermore, numerous bioinformatics analysis databases also reapplied to comprehensively explore and elucidate the oncogenic mechanism and therapeutic potential of EZH2 from pan-cancer insight. Finally, quantitative reverse transcription polymerase chain reaction and immunohistochemical assays were performed to verify the differential expression of EZH2 gene in various cancers at the mRNA and protein levels. EZH2 was widely expressed in multiple normal and tumor tissues, predominantly located in the nucleoplasm. Compared with matched normal tissues, EZH2 was aberrantly expressed in most cancers either at the mRNA or protein level, which might be caused by genetic mutations, DNA methylation, and protein phosphorylation. Additionally, EZH2 expression was correlated with clinical prognosis, and its up-regulation usually indicated poor survival outcomes in cancer patients. Subsequent analysis revealed that EZH2 could promote tumor immune evasion through T-cell dysfunction and T-cell exclusion. Furthermore, expression of EZH2 exhibited a strong correlation with several immunotherapy-associated responses (i.e., immune checkpoint molecules, tumor mutation burden (TMB), microsatellite instability (MSI), mismatch repair (MMR) status, and neoantigens), suggesting that EZH2 appeared to be a novel target for evaluating the therapeutic efficacy of immunotherapy.

Naming the Barriers between Anti-CCR5 Therapy, Breast Cancer and Its Microenvironment

Breast cancer represents the most common malignancy among women in the world. Although immuno-, chemo- and radiation therapy are widely recognized as the therapeutic trifecta, new strategies in the fight against breast cancer are continually explored. The local microenvironment around the tumor plays a great role in cancer progression and invasion, representing a promising therapeutic target. CCL5 is a potent chemokine with a physiological role of immune cell attraction and has gained particular attention in R&D for breast cancer treatment. Its receptor, CCR5, is a well-known co-factor for HIV entry through the cell membrane. Interestingly, biology research is unusually unified in describing CCL5 as a pro-oncogenic factor, especially in breast cancer. In silico, in vitro and in vivo studies blocking the CCL5/CCR5 axis show cancer cells become less invasive and less malignant, and the extracellular matrices produced are less oncogenic. At present, CCR5 blocking is a mainstay of HIV treatment, but despite its promising role in cancer treatment, CCR5 blocking in breast cancer remains unperformed. This review presents the role of the CCL5/CCR5 axis and its effector mechanisms, and names the most prominent hurdles for the clinical adoption of anti-CCR5 drugs in cancer.

Combining EZH2 inhibitors with other therapies for solid tumors: more choices for better effects

EZH2 is an epigenetic regulator that methylates lysine 27 on histone H3 (H3K27) and is closely related to the development and metastasis of tumors. It often shows gain-of-function mutations in hematological tumors, while it is often overexpressed in solid tumors. EZH2 inhibitors have shown good efficacy in hematological tumors in clinical trials but poor efficacy in solid tumors. Therefore, current research on EZH2 inhibitors has focused on exploring additional combination strategies in solid tumors. Herein we summarize the combinations and mechanisms of EZH2 inhibitors and other therapies, including immunotherapy, targeted therapy, chemotherapy, radiotherapy, hormone therapy and epigenetic therapy, both in clinical trials and preclinical studies, aiming to provide a reference for better antitumor effects.

Polycomb Directed Cell Fate Decisions in Development and Cancer

The polycomb group (PcG) proteins are a subset of transcription regulators highly conserved throughout evolution. Their principal role is to epigenetically modify chromatin landscapes and control the expression of master transcriptional programs to determine cellular identity. The two mayor PcG protein complexes that have been identified in mammals to date are Polycomb Repressive Complex 1 (PRC1) and 2 (PRC2). These protein complexes selectively repress gene expression via the induction of covalent post-translational histone modifications, promoting chromatin structure stabilization. PRC2 catalyzes the histone H3 methylation at lysine 27 (H3K27me1/2/3), inducing heterochromatin structures. This activity is controlled by the formation of a multi-subunit complex, which includes enhancer of zeste (EZH2), embryonic ectoderm development protein (EED), and suppressor of zeste 12 (SUZ12). This review will summarize the latest insights into how PRC2 in mammalian cells regulates transcription to orchestrate the temporal and tissue-specific expression of genes to determine cell identity and cell-fate decisions. We will specifically describe how PRC2 dysregulation in different cell types can promote phenotypic plasticity and/or non-mutational epigenetic reprogramming, inducing the development of highly aggressive epithelial neuroendocrine carcinomas, including prostate, small cell lung, and Merkel cell cancer. With this, EZH2 has emerged as an important actionable therapeutic target in such cancers.

lncRNA-AC079061.1/VIPR1 axis may suppress the development of hepatocellular carcinoma: a bioinformatics analysis and experimental validation

Background

Hepatocellular carcinoma (HCC) is one of the most malignant tumors to threaten human life, and the survival rate remains low due to delayed diagnosis. Meanwhile, lncRNAs have great potential for application in tumor prognosis, therefore relevant research in hepatocellular carcinoma is indispensable.

Methods

Based on the EZH2 expression, the differentially expressed lncRNAs DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) were identified in hepatocellular carcinoma by using the TCGA database. Bioinformatics technology was utilized to determine the effect of key genes in HCC progression. The methylation and immune infiltration analyses were performed to explore the underlying function of hub genes. Finally, cellular function experiments were performed to investigate the association between identified genes and biological phenotypes in HCC.

Results

lncRNA-AC079061.1, hsa-miR-765, and VIPR1 were identified as independent factors that affect the prognosis of hepatocellular carcinoma. The immune infiltration analyses revealed that lncRNA-AC079061.1 can alter the immune microenvironment and thus inhibit the development of HCC by regulating the expression of an immune-related gene (VIPR1). Methylation analyses demonstrated that VIPR1 expression is negatively related to the methylation level in HCC. Experimental results suggested that lncRNA-AC079061.1 and VIPR1 were frequently downregulated in HCC cells, while hsa-miR-765 was significantly upregulated. Moreover, the lncRNA-AC079061.1/VIPR1 axis suppressed the proliferation and invasion of HCC cells.

Conclusion

The present study identified the lncRNA-AC079061.1/VIPR1 axis as a novel biomarker that inhibited the proliferation and invasion of hepatocellular carcinoma, affecting the ultimate disease outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03573-7.

Regulation of CCL2 by EZH2 affects tumor-associated macrophages polarization and infiltration in breast cancer

Tumor associated macrophages (TAMs) play an important role in tumorigenesis, development and anti-cancer drug therapy. However, very few epigenetic compounds have been elucidated to affect tumor growth by educating TAMs in the tumor microenvironment (TME). Herein, we identified that EZH2 performs a crucial role in the regulation of TAMs infiltration and protumoral polarization by interacting with human breast cancer (BC) cells. We showed that EZH2 inhibitors-treated BC cells induced M2 macrophage polarization in vitro and in vivo, while EZH2 knockdown exhibited the opposite effect. Mechanistically, inhibition of EZH2 histone methyltransferase alone by EZH2 inhibitors in breast cancer cells could reduce the enrichment of H3K27me3 on CCL2 gene promoter, elevate CCL2 transcription and secretion, contributing to the induction of M2 macrophage polarization and recruitment in TME, which reveal a potential explanation behind the frustrating results of EZH2 inhibitors against breast cancer. On the contrary, EZH2 depletion led to DNA demethylation and subsequent upregulation of miR-124-3p level, which inhibited its target CCL2 expression in the tumor cells, causing arrest of TAMs M2 polarization. Taken together, these data suggested that EZH2 can exert opposite regulatory effects on TAMs polarization through its enzymatic or non-enzymatic activities. Our results also imply that the effect of antitumor drugs on TAMs may affect its therapeutic efficacy, and the combined application with TAMs modifiers should be warranted to achieve great clinical success.

Tumor-associated macrophage-derived chemokine CCL5 facilitates the progression and immunosuppressive tumor microenvironment of clear cell renal cell carcinoma

Background: Tumor-associated macrophages (TAMs) dominate the malignancy of cancers by perturbing the tumor microenvironment (TME). However, the clinical implications of heterogeneous subpopulations of TAMs in clear cell renal cell carcinoma (ccRCC) remain to be elucidated. Methods: We comprehensively evaluated the prognostic implications, biological behaviors, and immunogenomics features of the C-C Motif Chemokine Ligand 5 (CCL5) expression and CCL5+ TME in vitro and in 932 real-world ccRCC patients from testing and public validation cohorts. Flow cytometry was used to examine the functional patterns of CCL5+ TAMs with TME cell-infiltrating characterizations. Results: Our results identified distinct prognostic clusters with gradual changes in clinicopathological indicators based on CCL5 expression. Knockdown of CCL5 significantly restrained cell viability, migration capabilities of ccRCC cells, and the inhibits the proliferation and chemotaxis of THP1-derived TAMs. Mechanically, down-regulation of CCL5 arrested epithelial-mesenchymal transition by modulating the PI3K/AKT pathway in ccRCC cells. In ccRCC samples with CCL5 upregulation, the proportion of CCL5+ TAMs and PD-L1+ CD68+ TAMs were prominently increased, showing a typical suppressive tumor immune microenvironment (TIME). Besides, intra-tumoral CCL5+ TAMs showed distinct pro-tumorigenic TME features characterized by exhausted CD8+ T cells and increased expression of immune checkpoints. Furthermore, elevated CCL5+ TAMs infiltration was prominently associated with a dismal prognosis for patients with ccRCC. Conclusion: In conclusion, this study first revealed the predictive value of the chemokine CCL5 on the progression and TME of ccRCC. The intra-tumoral CCL5+ TAMs could be applied to comprehensively evaluate the prognostic patterns as well as unique TME characteristics among individuals, allowing for the identification of immunophenotypes and promotion of treatment efficiency for ccRCC.

Prediction of Prognosis in Patients with Hepatocellular Carcinoma Based on Molecular Subtypes of Immune Genes

For those patients with hepatocellular carcinoma (HCC), it is really a heavy burden. Herein, the immune genes of HCC were analyzed in groups to determine prognostic biomarkers related to immune genes in HCC. The mRNA data, clinical data in TCGA-LIHC dataset, and immune gene in the ImmPort database were collected for the combining usage with $K$ -means concordance clustering to cluster HCC patients according to the immune gene matrix. Based on ssGSEA analysis result, HCC patients were sorted into high- and low-immune subtypes, and survival curve presented that patients in high-immune subtypes had a better prognosis. Subsequently, differential expression analysis was performed to obtain immune-related differentially expressed genes (IRGs). Cox and lasso analyses were performed for obtaining five optimal immune genes related to prognosis, and a risk assessment model was then established. Patient samples in the training and validation sets were, respectively, divided into high- and low-risk groups. $K$ - $M$ survival curves presented a better prognosis of patients in the low-risk group than in the high-risk group. The ROC curve indicated that this model was finely used for the prediction of prognosis. In addition, immune infiltration assessment revealed that NR0B1 and FGF9 had potential to impact the tumor immune microenvironment. Finally, using qRT-PCR and transwell assays, it was demonstrated that the macrophage chemotaxis was enhanced when NR0B1 and FGF9 were highly expressed in HCC cells. In general, a 5-gene prognostic risk assessment model was constructed based on immune genes and bioinformatics analysis methods, which provides some reference for the prognosis of HCC as well as immunotherapy.

Non-coding RNAs and macrophage interaction in tumor progression

The macrophages are abundantly found in TME and their M2 polarization is in favor of tumor malignancy. On the other hand, non-coding RNAs (ncRNAs) can modulate macrophage polarization in TME to affect cancer progression. The miRNAs can dually induce/suppress M2 polarization of macrophages and by affecting various molecular pathways, they modulate tumor progression and therapy response. The lncRNAs can affect miRNAs via sponging and other molecular pathways to modulate macrophage polarization. A few experiments have also examined role of circRNAs in targeting signaling networks and affecting macrophages. The therapeutic targeting of these ncRNAs can mediate TME remodeling and affect macrophage polarization. Furthermore, exosomal ncRNAs derived from tumor cells or macrophages can modulate polarization and TME remodeling. Suppressing biogenesis and secretion of exosomes can inhibit ncRNA-mediated M2 polarization of macrophages and prevent tumor progression. The ncRNAs, especially exosomal ncRNAs can be considered as non-invasive biomarkers for tumor diagnosis.

The long and short non-coding RNAs modulating EZH2 signaling in cancer

Non-coding RNAs (ncRNAs) are a large family of RNA molecules with no capability in encoding proteins. However, they participate in developmental and biological processes and their abnormal expression affects cancer progression. These RNA molecules can function as upstream mediators of different signaling pathways and enhancer of zeste homolog 2 (EZH2) is among them. Briefly, EZH2 belongs to PRCs family and can exert functional roles in cells due to its methyltransferase activity. EZH2 affects gene expression via inducing H3K27me3. In the present review, our aim is to provide a mechanistic discussion of ncRNAs role in regulating EZH2 expression in different cancers. MiRNAs can dually induce/inhibit EZH2 in cancer cells to affect downstream targets such as Wnt, STAT3 and EMT. Furthermore, miRNAs can regulate therapy response of cancer cells via affecting EZH2 signaling. It is noteworthy that EZH2 can reduce miRNA expression by binding to promoter and exerting its methyltransferase activity. Small-interfering RNA (siRNA) and short-hairpin RNA (shRNA) are synthetic, short ncRNAs capable of reducing EZH2 expression and suppressing cancer progression. LncRNAs mainly regulate EZH2 expression via targeting miRNAs. Furthermore, lncRNAs induce EZH2 by modulating miRNA expression. Circular RNAs (CircRNAs), like lncRNAs, affect EZH2 expression via targeting miRNAs. These areas are discussed in the present review with a focus on molecular pathways leading to clinical translation.

EZH2, a prominent orchestrator of genetic and epigenetic regulation of solid tumor microenvironment and immunotherapy

Immune checkpoint blockade (ICB) is regarded as a promising strategy for cancer therapy. The histone methyltransferase, Enhancer of Zeste Homolog 2 (EZH2), has been implicated in the carcinogenesis of numerous solid tumors. However, the underlying mechanism of EZH2 in cancer immunotherapeutic resistance remains unknown. EZH2 orchestrates the regulation of the innate and adaptive immune systems of the tumor microenvironment (TME). Profound epigenetic and transcriptomic changes induced by EZH2 in tumor cells and immune cells mobilize the elements of the TME, leading to immune-suppressive activity of solid tumors. In this review, we summarized the dynamic functions of EZH2 on the different components of the TME, including tumor cells, T cells, macrophages, natural killer cells, myeloid-derived suppressor cells, dendritic cells, fibroblasts, and mesenchymal stem cells. Several ongoing anti-tumor clinical trials using EZH2 inhibitors have also been included as translational perspectives. In conclusion, based combinational therapy to enable ICB could offer a survival benefit in patients with cancer.

Tumor-associated macrophages in cancer: recent advancements in cancer nanoimmunotherapies

Cancer immunotherapy has emerged as a novel cancer treatment, although recent immunotherapy trials have produced suboptimal outcomes, with durable responses seen only in a small number of patients. The tumor microenvironment (TME) has been shown to be responsible for tumor immune escape and therapy failure. The vital component of the TME is tumor-associated macrophages (TAMs), which are usually associated with poor prognosis and drug resistance, including immunotherapies, and have emerged as promising targets for cancer immunotherapy. Recently, nanoparticles, because of their unique physicochemical characteristics, have emerged as crucial translational moieties in tackling tumor-promoting TAMs that amplify immune responses and sensitize tumors to immunotherapies in a safe and effective manner. In this review, we mainly described the current potential nanomaterial-based therapeutic strategies that target TAMs, including restricting TAMs survival, inhibiting TAMs recruitment to tumors and functionally repolarizing tumor-supportive TAMs to antitumor type. The current understanding of the origin and polarization of TAMs, their crucial role in cancer progression and prognostic significance was also discussed in this review. We also highlighted the recent evolution of chimeric antigen receptor (CAR)-macrophage cell therapy.

Analysis of EZH2 Genetic Variants on Triple-Negative Breast Cancer Susceptibility and Pathology

Triple-negative breast cancer (TNBC) is the third most common female cancer in Taiwan. EZH2 plays an important role in cancer development through transcriptional repression by chromatin remodeling. However, the expression of EZH2 in breast cancer is highly correlated with tumorigenesis, and patient survival is not matched to TNBC. Furthermore, it has not been determined if specific EZH2 genetic variants are associated with breast cancer risk. In this paper, we evaluated the survival of different types of breast cancer. The results indicated that a lower expression of EZH2 led to poor survival of TNBC patients. Therefore, we aimed at studying the relationship between genetic polymorphisms of EZH2 and susceptibility to TNBC in Taiwan. Four single-nucleotide polymorphisms (SNPs) of EZH2 (rs6950683, rs2302427, rs3757441, and rs41277434) were analyzed by real-time PCR genotyping in 176 patients with TNBC and 1000 cancer-free controls. The results showed that TNBC patients under 60 years old who carried a TC or CC genotype at EZH2 rs6950683 and re3757441 had a tumor size of 20 mm or smaller (T1). Thus, this study is the first to examine the age and mutant genes associated with EZH2 SNPs in TNBC progression and development in Taiwan.

CCL5/CCR5 axis in human diseases and related treatments

To defense harmful stimuli or maintain the immune homeostasis, the body produces and recruits a superfamily of cytokines such as interleukins, interferons, chemokines etc. Among them, chemokines act as crucial regulators in defense systems. CCL5/CCR5 combination is known for facilitating inflammatory responses, as well as inducing the adhesion and migration of different T cell subsets in immune responses. In addition, recent studies have shown that the interaction between CCL5 and CCR5 is involved in various pathological processes including inflammation, chronic diseases, cancers as well as the infection of COVID-19. This review focuses on how CCL5/CCR5 axis participates in the pathological processes of different diseases and their relevant signaling pathways for the regulation of the axis. Moreover, we highlighted the gene therapy and chemotherapy studies for treating CCR5-related diseases, including the ongoing clinical trials. The barriers and perspectives for future application and translational research were also summarized.

Tumor-associated macrophages in lung carcinoma: From mechanism to therapy

Tumor-associated macrophages (TAMs), which could be classified into the classical (M1-like) and alternatively activated (M2-like) phenotype, were considered to be important tumor-promoting components in lung cancer microenvironment. Several studies reported that TAMs in lung tumor islet or stroma are usually correlated with poor prognosis. Further studies showed that TAMs could promote the initiation of tumor cells, inhibit antitumor immune responses, and stimulate tumor angiogenesis and subsequently tumor metastasis of lung carcinoma. Currently, TAMs have been considered as penitential targets of lung cancer. This review summarizes from the fundamental information of TAMs to the its role in metastasis and present evidence for TAMs as a potential target of cancer therapy.

Development of a UPLC-MS/MS method for determination of a dual EZH1/2 inhibitor UNC1999 in rat plasma

Aim: We aimed to establish and validate a simple and sensitive UPLC-MS/MS method for the determination of UNC1999, a dual inhibitor against EZH1 and EZH2 in plasma samples. Materials & methods: UNC1999 in rat plasma was processed with protein precipitation method and then separated on a C₁₈ column and detected under positive ionization mode. The method presented good linearity over the range of 1.0-2000 ng/ml with good accuracy and precision. UNC1999 was absorbed slowly and achieved a maximum concentration of 118.8 ± 12.0 ng/ml 1.5 h after oral administration. Conclusion: The method provides a favorable character in selectivity, linearity, accuracy, precision, recovery, matrix effects and stabilities and was suitable for describing the pharmacokinetic profile of UNC1999.

Silencing of MBD2 and EZH2 inhibits the proliferation of colorectal carcinoma cells by rescuing the expression of SFRP

The secreted frizzled related proteins (SFRPs) are extracellular inhibitors of WNT pathway signaling. Methyl-CpG binding domain protein 2 (MBD2) and enhancer of zeste homolog 2 (EZH2) are core members of the methylated DNA binding domain (MBD) and polycomb group (PcG) protein families for epigenetic regulation, respectively. This study aimed to ascertain the potential role of MBD2 and EZH2 proteins in colorectal cancer (CRC) and its effects on the expression of SFRP. Bioinformatics, real-time quantitative polymerase chain reaction (qPCR) and western blot analysis were used to detect the expression of MBD2, EZH2, and SFRP in CRC cell lines and tissues. The functions of MBD2 and EZH2 in regards to cell proliferation, cell cycle distribution, apoptosis and invasion were examined in CRC cell lines. Methylation-specific PCR (MSP) was used to detect the methylation status of the SFRP promoter. The results revealed that the mRNA expression levels of SFRP were significantly decreased in CRC tissues and cell lines compared to these levels in the adjacent tissues and NCM460, respectively. However, the mRNA levels of EZH2 and MBD2 genes were highly expressed in CRC cell lines. We found that reducing MBD2 and EZH2 expression together remarkably inhibited and decreased the proliferation, migration and invasion abilities of the CRC cell lines compared to reducing one of each. Flow cytometric analysis showed that knockdown of MBD2 and EZH2 together in CRC affected cell apoptosis and the cell cycle progression more effectively than knockdown of one of each. The mRNA expression of SFRP1 was reactivated by silencing of MBD2 but not EZH2 in SW480 and HCT116 cells. SFRP4 and SFRP5 mRNA expression was reactivated by silencing of EZH2 but not MBD2 only in SW480 cells. However, depletion of both MBD2 and EZH2 restored SFRP1, SFRP2, SFRP4, and SFRP5 mRNA expression more effectively in CRC cells. Interestingly, there was no significant change in the methylation status of SFRP1, SFRP2, SFRP4, and SFRP5 gene promoter between before and after interference with MBD2, EZH2, and both. In conclusion, our results suggest that silencing of MBD2 and EZH2 simultaneously was able to rescue the expression of SFRP and inhibit the proliferation of CRC cells more effectively. However, the underlying regulatory mechanism system of MBD2 and EZH2 for SFRP in CRC requires further research.

Revisiting Lung Cancer Metastasis: Insight From the Functions of Long Non-coding RNAs

Globally, lung cancer is the most common cause of cancer-related deaths. After diagnosis at all stages, <7% of patients survive for 10 years. Thus, diagnosis at later stages and the lack of effective and personalized drugs reflect a significant need to better understand the mechanisms underpinning lung cancer progression. Metastasis should be responsible for the high lethality and recurrence rates seen in lung cancer. Metastasis depends on multiple crucial steps, including epithelial–mesenchymal transition, vascular remodeling, and colonization. Therefore, in-depth investigations of metastatic molecular mechanisms can provide valuable insights for lung cancer treatment. Recently, long noncoding RNAs (lncRNAs) have attracted considerable attention owing to their complex roles in cancer progression. In lung cancer, multiple lncRNAs have been reported to regulate metastasis. In this review, we highlight the major molecular mechanisms underlying lncRNA-mediated regulation of lung cancer metastasis, including (1) lncRNAs acting as competing endogenous RNAs, (2) lncRNAs regulating the transduction of several signal pathways, and (3) lncRNA coordination with enhancer of zeste homolog 2. Thus, lncRNAs appear to execute their functions on lung cancer metastasis by regulating angiogenesis, autophagy, aerobic glycolysis, and immune escape. However, more comprehensive studies are required to characterize these lncRNA regulatory networks in lung cancer metastasis, which can provide promising and innovative novel therapeutic strategies to combat this disease.

miR-101-3p Serves as a Tumor Suppressor for Renal Cell Carcinoma and Inhibits Its Invasion and Metastasis by Targeting EZH2

BACKGROUND

The role of miRNAs in renal cell carcinoma (RCC) is not certain. We wanted to study the biological functions and potential mechanisms of miR-101-3p in RCC.

METHODS

miR-101-3p was inhibited in A498 and OSRC-2 (two RCC cell lines). We studied its effect on cell invasion and proliferation. Target EZH2 of miR-101-3p was designated by different methods, including luciferase functional analysis and Western blotting. The expression level of the target gene in treated cells was quantitatively analyzed by quantitative real-time polymerase chain reaction. In addition, induction of miR-101-3p to prevent tumor formation of A498 cells in mice was further studied.

RESULTS

The overexpression of miR-101-3p significantly inhibited the proliferation, migration, and invasion in two RCC cells. Western blotting and luciferase functional analysis indicated that miR-101-3p regulated the expression of EZH2 in two cell lines. Mice inoculated with A498 and OSRC-2 cells transfected with miR-101-3p mimics showed significantly smaller xenografts and weaker EZH2 expression levels than the control group.

CONCLUSIONS

miR-101-3p inhibited RCC cell proliferation, migration, and invasion by targeting EZH2.

LINC00662 Promotes Oral Squamous Cell Carcinoma Cell Growth and Metastasis through miR-144-3p/EZH2 Axis

PURPOSE

Long non-coding RNA (lncRNA) is identified as an important regulator involved in oral squamous cell carcinoma (OSCC) tumorigenesis. This study aimed to investigate the functional role and underlying mechanism of LINC00662 in OSCC.

MATERIALS AND METHODS

The expression levels of LINC00662, miR-144-3p, and enhancer of zeste homolog 2 (EZH2) mRNA were quantified with quantitative real-time polymerase chain reaction in OSCC tissues and cell lines. Western blot analysis was used to assay the expression levels of E-cadherin, Vimentin, and EZH2. Cell proliferation, migration, and invasion were monitored by cell counting kit-8 and Transwell assays. Dual-luciferase reporter and RNA immunoprecipitation assays were employed to verify the regulatory relationship between LINC00662 and miR-144-3p.

RESULTS

The expression of LINC00662, positively associated with the increased TNM stage and lymph node metastasis of the patients, was up-regulated in OSCC tissues and cells. The overexpression of LINC00662 facilitated the proliferation, migration, and invasion of OSCC cells. MiR-144-3p could bind to LINC00662, and the promoting effect of LINC00662 overexpression was counteracted by miR-144-3p mimic. Moreover, EZH2 expression was negatively regulated by miR-144-3p and positively regulated by LINC00662. The silencing of EZH2 attenuated the promoting effects of overexpression of LINC00662 on cell proliferation, migration, invasion, and epithelial-mesenchymal transition.

CONCLUSION

LINC00662, as an oncogenic lncRNA of OSCC, accelerates OSCC progression by repressing miR-144-3p expression and increasing EZH2 expression.

Disruption of CCR5 signaling to treat COVID-19-associated cytokine storm: Case series of four critically ill patients treated with leronlimab

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C–C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0–7 and patient D (p=0.027) from day 0–14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

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Leronlimab is a monoclonal antibody in clinical trials to treat the cytokine storm.

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Critically ill patients received leronlimab through compassionate use and had remarkable recoveries measured objectively.

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The CCR5 receptor is important in recruiting inflammatory cells mainly T cells and macrophages.

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Leronlimab disrupted this signal and may have been responsible for restoration of the immune system, improved survival and decrease in IL-6.

Research trends in pharmacological modulation of tumor-associated macrophages

As one of the most abundant immune cell populations in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play important roles in multiple solid malignancies, including breast cancer, prostate cancer, liver cancer, lung cancer, ovarian cancer, gastric cancer, pancreatic cancer, and colorectal cancer. TAMs could contribute to carcinogenesis, neoangiogenesis, immune-suppressive TME remodeling, cancer chemoresistance, recurrence, and metastasis. Therefore, reprogramming of the immune-suppressive TAMs by pharmacological approaches has attracted considerable research attention in recent years. In this review, the promising pharmaceutical targets, as well as the existing modulatory strategies of TAMs were summarized. The chemokine-chemokine receptor signaling, tyrosine kinase receptor signaling, metabolic signaling, and exosomal signaling have been highlighted in determining the biological functions of TAMs. Besides, both preclinical research and clinical trials have suggested the chemokine-chemokine receptor blockers, tyrosine kinase inhibitors, bisphosphonates, as well as the exosomal or nanoparticle-based targeting delivery systems as the promising pharmacological approaches for TAMs deletion or reprogramming. Lastly, the combined therapies of TAMs-targeting strategies with traditional treatments or immunotherapies as well as the exosome-like nanovesicles for cancer therapy are prospected.

The Pharmacological TAILS of Matrix Metalloproteinases and Their Inhibitors

Matrix metalloproteinases (MMPs) have been demonstrated to have both detrimental and protective functions in inflammatory diseases. Several MMP inhibitors, with the exception of Periostat^®, have failed in Phase III clinical trials. As an alternative strategy, recent efforts have been focussed on the development of more selective inhibitors or targeting other domains than their active sites through specific small molecule inhibitors or monoclonal antibodies. Here, we present some examples that aim to better understand the mechanisms of conformational changes/allosteric control of MMPs functions. In addition to MMP inhibitors, we discuss unbiased global approaches, such as proteomics and N-terminomics, to identify new MMP substrates. We present some examples of new MMP substrates and their implications in regulating biological functions. By characterizing the roles and substrates of individual MMP, MMP inhibitors could be utilized more effectively in the optimal disease context or in diseases never tested before where MMP activity is elevated and contributing to disease progression.

Construction of a circRNA-miRNA-mRNA Network Related to Macrophage Infiltration in Hepatocellular Carcinoma

Immune cells in the tumor microenvironment play a crucial role in regulating tumor progression. The circular RNA (circRNA) regulatory network involved in immune cell infiltration in hepatocellular carcinoma (HCC) remains largely unknown. In this study, the “estimate the proportion of immune and cancer cells” (EPIC) application is used to evaluate the fractions of immune cells, cancer-associated fibroblasts, and endothelial cells in HCC from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Patients with a high macrophage fraction have better overall survival, and macrophage fraction is an independent prognostic factor for HCC. Next, the common differentially expressed mRNAs (DEmRNAs), miRNAs (DEmiRNAs), and circRNAs (DEcircRNAs) between paired tumor and non-tumor tissues are screened out from the TCGA and/or GEO databases. Through spearman correlation analysis, the macrophage-related DEmRNAs are identified to construct a circRNA-miRNA-mRNA regulatory network, which includes 6 DEcircRNAs, 7 DEmiRNAs, and 45 DEmRNAs. Functional enrichment analysis reveals that these DEmRNAs are mainly involved in immune-related processes. Furthermore, six hub DEmRNAs are identified to establish a hub circRNA regulatory network. Among the DEmRNAs in the network, PRC1 is identified as the most influential node. PRC1 high expression is correlated with poor prognosis and low macrophage infiltration in HCC. Taken together, we identify a certain circRNA regulatory network related to macrophage infiltration and provide novel insight into the mechanism of study and therapeutic targets for HCC.

EZH2 inhibition: a promising strategy to prevent cancer immune editing

Immunotherapies are revolutionizing the clinical management of a wide range of cancers. However, intrinsic or acquired unresponsiveness to immunotherapies does occur due to the dynamic cancer immunoediting which ultimately leads to immune escape. The evolutionarily conserved histone modifier enhancer of zeste 2 (EZH2) is aberrantly overexpressed in a number of human cancers. Accumulating studies indicate that EZH2 is a main driver of cancer cells' immunoediting and mediate immune escape through downregulating immune recognition and activation, upregulating immune checkpoints and creating an immunosuppressive tumor microenvironment. In this review, we overviewed the roles of EZH2 in cancer immunoediting, the preclinical and clinical studies of current pharmacologic EZH2 inhibitors and the prospects for EZH2 inhibitor and immunotherapy combination for cancer treatment.

EZH2: a novel target for cancer treatment

Enhancer of zeste homolog 2 (EZH2) is enzymatic catalytic subunit of polycomb repressive complex 2 (PRC2) that can alter downstream target genes expression by trimethylation of Lys-27 in histone 3 (H3K27me3). EZH2 could also regulate gene expression in ways besides H3K27me3. Functions of EZH2 in cells proliferation, apoptosis, and senescence have been identified. Its important roles in the pathophysiology of cancer are now widely concerned. Therefore, targeting EZH2 for cancer therapy is a hot research topic now and different types of EZH2 inhibitors have been developed. In this review, we summarize the structure and action modes of EZH2, focusing on up-to-date findings regarding the role of EZH2 in cancer initiation, progression, metastasis, metabolism, drug resistance, and immunity regulation. Furtherly, we highlight the advance of targeting EZH2 therapies in experiments and clinical studies.

The CCL5/CCR5 Axis in Cancer Progression

Tumor cells can “hijack” chemokine networks to support tumor progression. In this context, the C-C chemokine ligand 5/C-C chemokine receptor type 5 (CCL5/CCR5) axis is gaining increasing attention, since abnormal expression and activity of CCL5 and its receptor CCR5 have been found in hematological malignancies and solid tumors. Numerous preclinical in vitro and in vivo studies have shown a key role of the CCL5/CCR5 axis in cancer, and thus provided the rationale for clinical trials using the repurposed drug maraviroc, a CCR5 antagonist used to treat HIV/AIDS. This review summarizes current knowledge on the role of the CCL5/CCR5 axis in cancer. First, it describes the involvement of the CCL5/CCR5 axis in cancer progression, including autocrine and paracrine tumor growth, ECM (extracellular matrix) remodeling and migration, cancer stem cell expansion, DNA damage repair, metabolic reprogramming, and angiogenesis. Then, it focuses on individual hematological and solid tumors in which CCL5 and CCR5 have been studied preclinically. Finally, it discusses clinical trials of strategies to counteract the CCL5/CCR5 axis in different cancers using maraviroc or therapeutic monoclonal antibodies.