MicroRNAs and lncRNAs-A New Layer of Myeloid-Derived Suppressor Cells Regulation

Glioma-derived exosome Lncrna Agap2-As1 promotes glioma proliferation and metastasis by mediating Tgf-β1 secretion of myeloid-derived suppressor cells

Background

Glioma (GBM) is the most prevalent malignancy worldwide with high morbidity and mortality. Exosome-mediated transfer of long noncoding RNA (lncRNA) has been reported to be associated with human cancers, containing GBM. Meanwhile, myeloid-derived suppressor cells (MDSCs) play a vital role in mediating the immunosuppressive environments in GBM.

Objectives

This study is designed to explore the role and mechanism of exosomal (Exo) lncRNA AGAP2-AS1 on the MDSC pathway in GBM.

Methods

AGAP2-AS1, microRNA-486-3p (miR-486-3p), and Transforming growth factor beta-1 (TGF-β1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, and invasion were detected by 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, and Transwell assays. E-cadherin, Vimentin, CD9, CD81, and TGF-β1 protein levels were examined using Western blot. Exosomes were detected by a transmission electron microscope (TEM). Binding between miR-486-3p and AGAP2-AS1 or TGF-β1 was predicted by LncBase or TargetScan and then verified using a dual-luciferase reporter assay.

Results

AGAP2-AS1 was highly expressed in GBM tissues and cells. Functionally, AGAP2-AS1 absence or TGF-β1 knockdown repressed tumor cell growth and metastasis. Furthermore, Exo-AGAP2-AS1 from GBM cells regulated TGF-β1 expression via sponging miR-486-3p in MDSCs. Exo-AGAP2-AS1 upregulation facilitated GBM cell growth and metastasis via the MDSC pathway.

Conclusion

Exo-AGAP2-AS1 boosted GBM cell development partly by regulating the MDSC pathway, hinting at a promising therapeutic target for GBM treatment.

Exosomal-miRNas expression and growth factors released by mononuclear cells of CLAD patients in response to extracorporeal photopheresis

BACKGROUND

CLAD (Chronic Lung Allograft Dysfunction) remains a serious complication following lung transplantation. Some evidence shows that portions of Extracorporeal Photopheresis (ECP)-treated patients improve/stabilize their graft function. In spite of that, data concerning molecular mechanisms are still lacking. Aims of our study were to assess whether ECP effects are mediated by Mononuclear Cells (MNCs) modulation in term of microRNAs (miRNAs) expression and growth factors release.

METHODS

Cells from leukapheresis of 16 CLAD patients, at time 0 and 6-months (10 cycles), were cultured for 48h ± PHA (10 ug/ml) or LPS (2 ug/ml). Expression levels of miR-146a-5p, miR-155-5p, miR-31-5p, miR181a-5p, miR-142-3p, miR-16-5p and miR-23b-5p in MNCs-exosomes were evaluated by qRT-PCR, while ELISA assessed different growth factors levels on culture supernatants.

RESULTS

Our result showed miR-142-3p down-regulation (p = 0.02) in MNCs of ECP-patients after the 10 cycles and after LPS stimulation (p = 0.005). We also find miR-146a-5p up-regulation in cells after the 10 cycles stimulated with LPS (p = 0.03). Connective tissue growth factor (CTGF) levels significantly decreased in MNCs supernatant (p = 0.04). The effect of ECP is translated into frequency changes of Dendritic Cell (DC) subpopulations and a slight increase in T regulatory cells (Treg) number and a significant decrease in CTGF release.

CONCLUSIONS

ECP might affect regulatory T cell functions, since both miR-142 and miR-146a have been shown to be involved in the regulation of suppressor regulatory T cell functions and DCs. On the other side ECP, possibly by regulating macrophage activation, is able to significantly down modulate CTGF release.

The immunomodulatory role of exosomal microRNA networks in the crosstalk between tumor-associated myeloid-derived suppressor cells and tumor cells

Myeloid-derived suppressor cells (MDSCs) are considered a heterogeneous group of immature myeloid cells engaging in aggressive tumor progression and metastasis in the tumor microenvironment (TME) of patients diagnosed with cancer, through downregulation of anti-tumor immune responses. Exosomes are small vesicles carrying specific cargos, including proteins, lipids, and MicroRNA (miRNAs). Such exosomal miRNAs delivered by MDSCs and tumor cells are short noncoding RNAs mediating some of the immunosuppressive characteristics of MDSCs in the TME. However, when it comes to cancer diseases, how these miRNAs interact with MDSCs and encourage MDSCs differentiation and function need further investigations. In this review, we discuss MDSC-derived exosomal miRNAs and those derived from tumor cells (TDE) could modulate anti-tumor immunity and regulate the interaction between tumor cells and MDSCs in the TME. Afterward, we focus on dividing miRNAs, as an important substance interacting with MDSCs and tumor cells in the TME, into those have an immunosuppressive or stimulating effect not only on MDSCs expansion, differentiation, and suppressive function but also on tumor evasion.

The Interaction of Programmed Cell Death Protein and Its Ligands with Non-Coding RNAs in Neoplasms: Emerging Anticancer Immunotherapeutics

Recent studies have demonstrated that cancer cells can elude immune cells by creating a sanctuary within the tumor’s microenvironment. Large amounts of immune-suppressing signaling proteins can be expressed by cancer cells. One of the most important mechanisms in this system is immune suppression caused by tumors and the modulation of the immune checkpoint. The immune checkpoint is modulated by both the programmed cell death protein 1 (PD-1) and its ligands, programmed death ligand 1 (PD-L1) and PD-L2. Non-coding RNAs (ncRNA), including the more well-known microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), all play roles in the regulation of biological processes and extensive diseases such as cancer. Thus, the focus of this study is on the interactions between the programmed death protein and its ligands with miRNAs, lncRNAs, and circRNAs during tumorigenesis and tumor progression. Furthermore, some FDA-approved drugs for the treatment of various cancers were based on their interactions with PD-1, PD-Ls, and ncRNAs. This promising strategy is still in the production stages, with additional results and clinical trials being processed.

A comprehensive review of the role of lncRNAs in gastric cancer (GC) pathogenesis, immune regulation, and their clinical applications

Gastric cancer (GC) is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide. Although numerous studies have been conducted on advanced GC, the molecular mechanisms behind it remain obscure. Long non-coding RNAs (lncRNAs) are a family of RNA transcripts capable of regulating target genes at transcriptional, post-transcriptional, and translational stages. They do this by modifying mRNAs, miRNAs, and proteins. These RNAs are critical regulators of many biological processes, including gene epigenetics, transcription, and post-transcriptional levels. This article highlights recent results on lncRNAs involved in drug resistance, proliferation, migration, angiogenesis, apoptosis, autophagy, and immune response in GC. The potential clinical implications of lncRNAs as biomarkers and therapeutic targets in GC are also discussed.

A comprehensive review about the utilization of immune checkpoint inhibitors and combination therapy in hepatocellular carcinoma: an updated review

A pharmacological class known as immune checkpoint inhibitors (ICIs) has been developed as a potential treatment option for various malignancies, including HCC. In HCC, ICIs have demonstrated clinically significant advantages as monotherapy or combination therapy. ICIs that target programmed cell death protein 1 (PD-1) and programmed cell death protein ligand 1 (PD-L1), as well as cytotoxic T lymphocyte antigen 4 (CTLA-4), have made significant advances in cancer treatment. In hepatocellular carcinoma (HCC), several ICIs are being tested in clinical trials, and the area is quickly developing. As immunotherapy-related adverse events (irAEs) linked with ICI therapy expands and gain worldwide access, up-to-date management guidelines become crucial to the safety profile of ICIs. This review aims to describe the evidence for ICIs in treating HCC, emphasizing the use of combination ICIs.

MicroRNAs/LncRNAs Modulate MDSCs in Tumor Microenvironment

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immature cells derived from bone marrow that play critical immunosuppressive functions in the tumor microenvironment (TME), promoting cancer progression. According to base length, Non-coding RNAs (ncRNAs) are mainly divided into: microRNAs (miRNAs), lncRNAs, snRNAs and CircRNAs. Both miRNA and lncRNA are transcribed by RNA polymerase II, and they play an important role in gene expression under both physiological and pathological conditions. The increasing data have shown that MiRNAs/LncRNAs regulate MDSCs within TME, becoming one of potential breakthrough points at the investigation and treatment of cancer. Therefore, we summarize how miRNAs/lncRNAs mediate the differentiation, expansion and immunosuppressive function of tumor MDSCs in TME. We will then focus on the regulatory mechanisms of exosomal MicroRNAs/LncRNAs on tumor MDSCs. Finally, we will discuss how the interaction of miRNAs/lncRNAs modulates tumor MDSCs.

The Role of Critical N6-Methyladenosine-Related Long Non-Coding RNAs and Their Correlations with Immune Checkpoints in Renal Clear Cell Carcinoma

Purpose

This study aimed to evaluate the functions of critical N6-methyladenosine (m6A)-related long non-coding RNAs (lncRNAs) and their correlations with immunotherapeutic targets in clear cell renal cell carcinoma (ccRCC).

Methods

m6A-related lncRNAs were analyzed using the dataset from The Cancer Genome Atlas database via Pearson correlation analysis. Then, their prognostic functions in patients with ccRCC were determined via univariate Cox analysis. A prognostic m6A-related lncRNA signature (MRLS) in ccRCC was established using the least absolute shrinkage and selection operator (LASSO) Cox regression model. In addition, the correlations between these prognostic m6A-related lncRNAs with immune checkpoints were further evaluated in clinical samples.

Results

MRLS was established by the LASSO Cox regression model on the basis of seven prognostic m6A-related lncRNAs. The risk score for each patient was calculated using the MRLS model, and the patients were further stratified into high- and low-risk subgroups. The MRLS model was validated with a robust prognostic ability by the stratification analysis. On the basis of age, grade, stage, and risk score, a nomogram was developed with a strong reliability in forecasting the overall survival percentages of the patients with ccRCC. Moreover, seven prognostic m6A-related lncRNAs enrolled in the MRLS model were found to be correlated with various immunotherapeutic targets, namely, PD-1, PD-L1, CTLA4, and LAG3, and the expression levels of which in the high-risk subgroup were significantly higher than those in the low-risk subgroup. The significant correlations between LINC00342 and the aforementioned immunotherapeutic targets were also confirmed in clinical samples.

Conclusion

In this study, seven m6A-related lncRNAs were identified as potential biomarkers for forecasting the prognosis of patients with ccRCC and evaluating the efficacy of immunotherapy for these patients. Furthermore, a prognostic and predictive MRLS model with a high reliability was constructed to predict the overall survival probability of patients with ccRCC.

Silencing tumor-intrinsic CD73 enhances the chemosensitivity of NSCLC and potentiates the anti-tumoral effects of cisplatin: An in vitro study

AIMS

Besides suppressing anti-tumoral immune responses, tumor-intrinsic inhibitory immune checkpoints have been implicated in tumor development. Herein, we aimed to investigate the significance of tumor-intrinsic CD73, as an inhibitory immune checkpoint, in non-small cell lung cancer (NSCLC) development and propose a novel therapeutic approach.

MAIN METHODS

We investigated the cell viability, chemosensitivity, apoptosis, migration, and the cell cycle of A-549 and NCI-H1299 following treatment with cisplatin and CD73-small interfering RNA (siRNA) transfection. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to study the viability of studied groups and chemosensitivity of tumoral cells. Flow cytometry and 4',6-diamidino-2-phenylindole (DAPI) staining were used to investigate the apoptosis of NSCLC cells. Flow cytometry and the wound-healing assay were used to investigate the cell cycle and migration of NSCLC cells, respectively. The mRNA expression levels of c-Myc, caspase 3, ROCK, and MMP-9 were investigated to study the underlying molecular mechanism.

KEY FINDINGS

CD73-siRNA transfection has significantly decreased the cell viability and enhanced the chemosensitivity of A-549 and NCI-H1299 cells to cisplatin. CD73-siRNA has considerably stimulated apoptosis, arrested the cell cycle, inhibited tumor migration, downregulated the mRNA expression of c-Myc, MMP-9, and ROCK, and upregulated caspase 3 expression in NSCLC cells. Besides, combined cisplatin therapy with CD73-siRNA transfection has potentiated the aforementioned anti-tumoral effects of cisplatin on NSCLC cells.

SIGNIFICANCE

Besides suppressing anti-tumoral immune responses, tumor-intrinsic CD73 can facilitate NSCLC development, and the combined cisplatin therapy with CD73-siRNA transfection can substantially enhance the chemosensitivity of NSCLC to cisplatin and potentiates cisplatin-induced anti-tumoral effects on NSCLC.

Integrated analysis on the N6-methyladenosine-related long noncoding RNAs prognostic signature, immune checkpoints, and immune cell infiltration in clear cell renal cell carcinoma

Background

Patients with advanced clear cell renal cell carcinoma (ccRCC) have a poor prognosis and lack effective prognostic biomarkers. N6‐methyladenosine‐related lncRNAs (m6A‐related long noncoding RNAs [lncRNAs]) have been confirmed to be associated with the development of multiple tumors, but its role in ccRCC is not clear.

Methods

Gene expression data and clinical information of ccRCC patients were extracted from The Cancer Genome Atlas Database. The prognostic m6A‐related lncRNAs were obtained by Pearson's correlation analysis and univariate Cox regression analysis. Afterward, the cluster classification and its correlation with prognosis, clinical characteristics, and immunity were analyzed. LASSO regression was used to establish the prognostic risk model. The predictive performance of the prognostic model was evaluated and validated by survival analysis and receiver operating characteristic curve analysis, et al. The expression of immune checkpoints and immune cell infiltration in patients with different risks were systematically analyzed.

Results

A total of 27 prognostic m6A‐related lncRNAs were identified. These m6A‐related lncRNAs were differentially expressed between tumor and normal tissues. Among them, 24 high‐risk m6A‐related lncRNAs were overexpressed in Cluster 2 and correlated with poor prognosis, low stromal score, high expression of immune checkpoints, and immunosuppressive cells infiltration. Based upon, a prognostic risk model composed of seven m6A‐related lncRNAs was constructed. After a series of analyses, it was proved that this model had good sensitivity and specificity, and could predict the prognosis of patients with different clinical stratification. The expression of PD‐1, PD‐L1, CTLA‐4, LAG‐3, TIM‐3, and TIGIT were significantly increased in the high‐risk patients, and there was a correlation between the risk score and immune cell infiltration.

Conclusions

The seven m6A‐related lncRNAs prognostic risk signature showed reliable prognostic predictive power for ccRCC and was associated with the expression of immune checkpoints and immune cell infiltration. This seven m6A‐related lncRNAs signature will be helpful in managing ccRCC and guiding individualized immunotherapy.

Immune Checkpoint Inhibitors in Colorectal Cancer: Challenges and Future Prospects

Immunotherapy is a new pillar of cancer therapy that provides novel opportunities to treat solid tumors. In this context, the development of new drugs targeting immune checkpoints is considered a promising approach in colorectal cancer (CRC) treatment because it can be induce specific and durable anti-cancer effects. Despite many advances in the immunotherapy of CRC, there are still limitations and obstacles to successful treatment. The immunosuppressive function of the tumor microenvironment (TME) is one of the causes of poor response to treatment in CRC patients. For this reason, checkpoint-blocking antibodies have shown promising outcomes in CRC patients by blocking inhibitory immune checkpoints and enhancing immune responses against tumors. This review summarizes recent advances in immune checkpoint inhibitors (ICIs), such as CTLA-4, PD-1, PD-L1, LAG-3, and TIM-3 in CRC, and it discusses various therapeutic strategies with ICIs, including the double blockade of ICIs, combination therapy of ICIs with other immunotherapies, and conventional treatments. This review also delineates a new hopeful path in the combination of anti-PD-1/anti-PD-L1 with other ICIs such as anti-CTLA-4, anti-LAG-3, and anti-TIM-3 for CRC treatment.

Myeloid-Derived Suppressor Cells as Therapeutic Targets in Uterine Cervical and Endometrial Cancers

Uterine cervical and endometrial cancers are the two most common gynecological malignancies. As demonstrated in other types of solid malignancies, an increased number of circulating or tumor-infiltrating myeloid-derived suppressor cells (MDSCs) have also been observed in uterine cervical and endometrial cancers, and increased MDSCs are associated with an advanced stage, a short survival, or a poor response to chemotherapy or radiotherapy. In murine models of uterine cervical and endometrial cancers, MDSCs have been shown to play important roles in the progression of cancer. In this review, we have introduced the definition of MDSCs and their functions, discussed the roles of MDSCs in uterine cervical and endometrial cancer progression, and reviewed treatment strategies targeting MDSCs, which may exhibit growth-inhibitory effects and enhance the efficacy of existing anticancer treatments.

Resistance to Immune Checkpoint Inhibitors Secondary to Myeloid-Derived Suppressor Cells: A New Therapeutic Targeting of Haematological Malignancies

Myeloid-derived suppressor cells (MDSCs) are a set of immature myeloid lineage cells that include macrophages, granulocytes, and dendritic cell precursors. This subpopulation has been described in relation to the tumour processes at different levels, including resistance to immunotherapy, such as immune checkpoint inhibitors (ICIs). Currently, multiple studies at the preclinical and clinical levels seek to use this cell population for the treatment of different haematological neoplasms, together with ICIs. This review addresses the different points in ongoing studies of MDSCs and ICIs in haematological malignancies and their future significance in routine clinical practice.

Transforming growth factor-beta1 and myeloid-derived suppressor cells: A cancerous partnership

Transforming growth factor-beta1 (TGF-β1) plays a crucial role in tumor progression. It can inhibit early cancer stages but promotes tumor growth and development at the late stages of tumorigenesis. TGF-β1 has a potent immunosuppressive function within the tumor microenvironment that largely contributes to tumor cells' immune escape and reduction in cancer immunotherapy responses. Likewise, myeloid-derived suppressor cells (MDSCs) have been postulated as leading tumor promoters and a hallmark of cancer immune evasion mechanisms. This review attempts to analyze the prominent roles of both TGF-β1 and MDSCs and their interplay in cancer immunity. Furthermore, therapies against either TGF-β1 or MDSCs, and their potential synergistic combination with immunotherapies are discussed. Simultaneous TGF-β1 and MDSCs inhibition suggest a potential improvement in immunotherapy or subverted tumor immune resistance.