MicroRNA-200a induces immunosuppression by promoting PTEN-mediated PD-L1 upregulation in osteosarcoma

MicroRNA-200c in Cancer Generation, Invasion, and Metastasis

MicroRNA-200c (miR-200c) is increasingly recognized as a crucial small RNA molecule that plays a significant and multifaceted role in the complex processes of tumor development, invasion, and metastasis across various types of cancers. Recent studies have compellingly demonstrated that miR-200c exerts its influence on tumor biology by meticulously regulating a range of critical processes, including cell proliferation, apoptosis, epithelial-mesenchymal transition (EMT), and cell migration, all of which are essential for the progression and aggressiveness of tumors. This comprehensive review aims to summarize the expression characteristics and functional implications of miR-200c across a diverse array of tumor types, delving into its potential utility as both a biomarker for early detection and a therapeutic target in the realm of cancer treatment. By synthesizing current research findings and insights, we aspire to provide valuable information that could significantly enhance early diagnostic capabilities and inform the strategic development of targeted therapy approaches in oncology.

Exploring the tumor-suppressive role of miRNA-200c in head and neck squamous cell carcinoma: Potential and mechanisms of exosome-mediated delivery for therapeutic applications

Head and neck squamous cell carcinoma (HNSCC) remains a challenging malignancy due to its high rates of recurrence, metastasis, and resistance to conventional therapies. microRNA-200c (miRNA-200c) has emerged as a critical tumor suppressor in HNSCC, with the potential to inhibit epithelial-mesenchymal transition (EMT), which is considered as a key process in cancer metastasis and progression. Interestingly, there are also controversial findings in HNSCC characterizing miRNA-200c as oncogenic factor. This review article provides a comprehensive overview of the current understanding of miRNA-200c's general role in cancer, and particularly in HNSCC, highlighting its mechanisms of action, including the regulation of EMT and other oncogenic pathways. Additionally, the review explores the innovative approach of exosome-mediated delivery of miRNA-200c as a therapeutic strategy. Exosomes, as natural nanocarriers, offer a promising vehicle for the targeted delivery of miRNA-200c to tumor cells, potentially overcoming the limitations of traditional delivery methods and enhancing therapeutic efficacy. The review also discusses the challenges and future directions in the clinical application of miRNA-200c, particularly focusing on its potential to improve outcomes for HNSCC patients. This article seeks to provide valuable insights for researchers and clinicians working towards innovative treatments for this aggressive cancer type.

Unraveling the interplay of CD8 + T cells and microRNA signaling in cancer: implications for immune dysfunction and therapeutic approaches

MicroRNAs (miRNAs) emerge as critical regulators of CD8 + T cell function within the complex tumor microenvironment (TME). This review explores the multifaceted interplay between miRNAs and CD8 + T cells across various cancers. We discuss how specific miRNAs influence CD8 + T cell activation, recruitment, infiltration, and effector function. Dysregulation of these miRNAs can contribute to CD8 + T cell exhaustion and immune evasion, hindering anti-tumor immunity. Conversely, manipulating miRNA expression holds promise for enhancing CD8 + T cell activity and improving cancer immunotherapy outcomes. We delve into the role of miRNAs in CD8 + T-cell function across different cancer types, including gliomas, gastric and colon cancer, oral squamous cell carcinoma, thyroid carcinoma, lymphomas, melanoma, breast cancer, renal cell carcinoma, ovarian cancer, uterine corpus endometrial cancer, bladder cancer, acute myeloid leukemia, chronic myelogenous leukemia, and osteosarcoma. Additionally, we explore how extracellular vesicles and cytokines modulate CD8 + T-cell function through complex interactions with miRNAs. Finally, we discuss the potential impact of radiotherapy and specific drugs on miRNA expression and CD8 + T-cell activity within the TME. This review highlights the immense potential of targeting miRNAs to manipulate CD8 + T-cell activity for the development of novel and improved cancer immunotherapies.

Advancements in osteosarcoma management: integrating immune microenvironment insights with immunotherapeutic strategies

Osteosarcoma, a malignant bone tumor predominantly affecting children and adolescents, presents significant therapeutic challenges, particularly in metastatic or recurrent cases. Conventional surgical and chemotherapeutic approaches have achieved partial therapeutic efficacy; however, the prognosis for long-term survival remains bleak. Recent studies have highlighted the imperative for a comprehensive exploration of the osteosarcoma immune microenvironment, focusing on the integration of diverse immunotherapeutic strategies-including immune checkpoint inhibitors, tumor microenvironment modulators, cytokine therapies, tumor antigen-specific interventions, cancer vaccines, cellular therapies, and antibody-based treatments-that are directly pertinent to modulating this intricate microenvironment. By targeting tumor cells, modulating the tumor microenvironment, and activating host immune responses, these innovative approaches have demonstrated substantial potential in enhancing the effectiveness of osteosarcoma treatments. Although most of these novel strategies are still in research or clinical trial phases, they have already demonstrated significant potential for individuals with osteosarcoma, suggesting the possibility of developing new, more personalized and effective treatment options. This review aims to provide a comprehensive overview of the current advancements in osteosarcoma immunotherapy, emphasizing the significance of integrating various immunotherapeutic methods to optimize therapeutic outcomes. Additionally, it underscores the imperative for subsequent research to further investigate the intricate interactions between the tumor microenvironment and the immune system, aiming to devise more effective treatment strategies. The present review comprehensively addresses the landscape of osteosarcoma immunotherapy, delineating crucial scientific concerns and clinical challenges, thereby outlining potential research directions.

PROGNOSTIC IMPLICATIONS OF PD-L1 EXPRESSION AND LOSS OF PTEN IN PATIENTS WITH RHABDOMYOSARCOMA, EWING'S SARCOMA AND OSTEOSARCOMA

BACKGROUND

In children, osteosarcoma (OS), Ewing's sarcoma (ES), and rhabdomyosarcoma (RMS) are the most common sarcomas. A link between the anti-programmed death ligand-1 PD-L1 and the tumor suppressor phosphatase and tensin homologue (PTEN) expression has been described in many tumors. The aim of this work is to determine clinicopathological relationships and the possible prognostic significance of PD-L1 and PTEN expression in rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), and osteosarcoma (OS).

MATERIALS AND METHODS

Expression of PD-L1 and PTEN were examined by immunohistochemistry in 45 archival RMS, ES, and OS cases.

RESULTS

The positive expression of PD-L1 was found in 16.7% and 31.6% of ES and OS, respectively. The negative PD-L1 was related to a substantially longer survival in ES cases (p = 0.045), but positive PD-L1 expression was significantly associated with the increased tumor stage and vascular invasion in the OS cases (p = 0.005 and p = 0.002), respectively. On the other hand, PTEN loss was strongly associated with deep tumor, high tumor grade, and recurrence in RMS (p = 0.002, p = 0.045, and p = 0.026, respectively). However, PTEN loss was significantly absent in ES as tumor grade increased (p = 0.031). It is noteworthy that tumor recurrence, the loss of PTEN, and positive PD-L1 were all considered predictive factors in OS patients (p = 0.045, p = 0.032, and p = 0.02, respectively).

CONCLUSIONS

In children, OS and ES have positive PD-L1 expression, which has an independent unfavorable prognostic effect and raises the possibility of using PD-L1 as a therapeutic target. OS, ES, and RMS prognosis are all predicted by PTEN loss.

Radix Bupleuri-Radix Paeoniae Alba Inhibits the Development of Hepatocellular Carcinoma through Activation of the PTEN/PD-L1 Axis within the Immune Microenvironment

OBJECTIVE

This study investigated how Radix Bupleuri-Radix Paeoniae Alba (BP) was active against hepatocellular carcinoma (HCC).

METHODS

Traditional Chinese medicine systems pharmacology (TCMSP) database was employed to determine the active ingredients of BP and potential targets against HCC. Molecular docking analysis verified the binding activity of PTEN with BP ingredients. H22 cells were used to establish an HCC model in male balb/c mice. Immunofluorescence staining, immunohistochemistry, flow cytometry, western blotting, enzyme-linked immunosorbent assay, and real-time quantitative PCR were used to study changes in proliferation, apoptosis, PTEN levels, inflammation, and T-cell differentiation in male balb/c mice.

RESULTS

The major active ingredients in BP were found to be quercetin, kaempferol, isorhamnetin, stigmasterol, and beta-sitosterol. Molecular docking demonstrated that these five active BP ingredients formed a stable complex with PTEN. BP exhibited an anti-tumor effect in our HCC mouse model. BP was found to increase the CD8+ and IFN-γ+/CD4+ T cell levels while decreasing the PD-1+/CD8+ T and Treg cell levels in HCC mice. BP up-regulated the IL-6, IFN-γ, and TNF-α levels but down-regulated the IL-10 levels in HCC mice. After PTEN knockdown, BP-induced effects were abrogated.

CONCLUSION

BP influenced the immune microenvironment through activation of the PTEN/PD-L1 axis, protecting against HCC.

New emerging targets in osteosarcoma therapy: PTEN and PI3K/Akt crosstalk in carcinogenesis

Osteosarcoma (OS) is a malignant bone carcinoma that affects people in childhood and adulthood. The heterogeneous nature and chromosomal instability represent certain characteristics of OS cells. These cancer cells grow and migrate abnormally, making the prognosis undesirable for patients. Conventional and current treatments fail to completely eradicate tumor cells, so new therapeutics targeting genes may be considered. PI3K/Akt is a regulator of events such as growth, cell death, migration, and differentiation, and its expression changes during cancer progression. PTEN reduces PI3K/Akt expression, and its mutations and depletions have been reported in various tumors. Experimental evidence shows that there is upregulation of PI3K/Akt and downregulation of PTEN in OS. Increasing PTEN expression may suppress PI3K/Akt to minimize tumorigenesis. In addition, PI3K/Akt shows a positive association with growth, metastasis, EMT and metabolism of OS cells and inhibits apoptosis. Importantly, overexpression of PI3K/Akt causes drug resistance and radio-resistance and its level can be modulated by miRNAs, lncRNAs and circRNAs. Silencing PI3K/Akt by compounds and drugs can suppress OS. Here, we review in detail the function of the PTEN/PI3K/Akt in OS, revealing its biological function, function in tumor progression, resistance to therapy, and pharmacological significance.

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

A spotlight on the interplay of signaling pathways and the role of miRNAs in osteosarcoma pathogenesis and therapeutic resistance

Osteosarcoma (OS) is one of the most common bone cancers that constantly affects children, teenagers, and young adults. Numerous epigenetic elements, such as miRNAs, have been shown to influence OS features like progression, initiation, angiogenesis, and treatment resistance. The expression of numerous genes implicated in OS pathogenesis might be regulated by miRNAs. This effect is ascribed to miRNAs' roles in the invasion, angiogenesis, metastasis, proliferation, cell cycle, and apoptosis. Important OS-related mechanistic networks like the WNT/b-catenin signaling, PTEN/AKT/mTOR axis, and KRAS mutations are also affected by miRNAs. In addition to pathophysiology, miRNAs may influence how the OS reacts to therapies like radiotherapy and chemotherapy. With a focus on how miRNAs affect OS signaling pathways, this review seeks to show how miRNAs and OS are related.

Macrophage Repolarization as a Therapeutic Strategy for Osteosarcoma

Macrophages are versatile immune cells and can adapt to both external stimuli and their surrounding environment. Macrophages are categorized into two major categories; M1 macrophages release pro-inflammatory cytokines and produce protective responses that lead to antimicrobial or antitumor activity. M2 or tumor-associated macrophages (TAM) release anti-inflammatory cytokines that support tumor growth, invasion capacity, and metastatic potential. Since macrophages can be re-polarized from an M2 to an M1 phenotype with a variety of strategies, this has emerged as an innovative anti-cancer approach. Osteosarcoma (OS) is a kind of bone cancer and consists of a complex niche, and immunotherapy is not very effective. Therefore, immediate attention to new strategies is required. We incorporated the recent studies that have used M2-M1 repolarization strategies in the aspect of treating OS cancer.

Identification of therapeutic targets for osteosarcoma by integrating single-cell RNA sequencing and network pharmacology

Background: Osteosarcoma (OS) is a common primary tumor with extensive heterogeneity. In this study, we used single-cell RNA sequencing (scRNA-seq) and network pharmacology to analyze effective targets for Osteosarcoma treatment. Methods: The cell heterogeneity of the Osteosarcoma single-cell dataset GSE162454 was analyzed using the Seurat package. The bulk-RNA transcriptome dataset GSE36001 was downloaded and analyzed using the CIBERSORT algorithm. The key targets for OS therapy were determined using Pearson's correlation analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed on key targets. The DeepDR algorithm was used to predict potential drugs for Osteosarcoma treatment. Molecular docking analysis was performed to verify the binding abilities of the predicted drugs and key targets. qRT-PCR assay was used to detect the expression of key targets in osteoblasts and OS cells. Results: A total of 21 cell clusters were obtained based on the GSE162454 dataset, which were labeled as eight cell types by marker gene tagging. Four cell types (B cells, cancer-associated fibroblasts (CAFs), endothelial cells, and plasmocytes) were identified in Osteosarcoma and normal tissues, based on differences in cell abundance. In total, 17 key targets were identified by Pearson's correlation analysis. GO and KEGG analysis showed that these 17 genes were associated with immune regulation pathways. Molecular docking analysis showed that RUNX2, OMD, and CD4 all bound well to vincristine, dexamethasone, and vinblastine. The expression of CD4, OMD, and JUN was decreased in Osteosarcoma cells compared with osteoblasts, whereas RUNX2 and COL9A3 expression was increased. Conclusion: We identified five key targets (CD4, RUNX2, OMD, COL9A3, and JUN) that are associated with Osteosarcoma progression. Vincristine, dexamethasone, and vinblastine may form a promising drug-target pair with RUNX2, OMD, and CD4 for Osteosarcoma treatment.

The expression of miR-181b, CYLD, CBX-7, BCL2, and p53 in osteosarcoma patients and correlation with clinicopathological factors

Osteosarcoma is a common human malignancy with a high mortality rate worldwide. Recent studies have been focused on understanding the involvement of microRNA (miRNAs) in the pathogenesis of osteosarcoma. Therefore, the present study aimed to measure the expression levels of miR-181a, cylindromatosis (CYLD), chromo box homolog 7 (CBX7), B-cell lymphoma 2 (BCL2), and tumor protein p53 in tumor tissue and adjacent normal tissues in patients with osteosarcoma and its relationship with clinicopathological factors. The expression levels of miR-181a, CYLD, CBX7, BCL2, and p53 were measured in 60 patients with osteosarcoma using quantitative real-time polymerase chain reaction. Finally, we compared the relationship between these gene levels and clinicopathological factors in tumor and healthy tissues. Our results showed that the expression levels of miR-181a, BCL2, and p53 were significantly higher in osteosarcoma tissue in comparison with normal tissues (p < .05). On the contrary, CYLD and CBX7 were downregulated in osteosarcoma tumor tissues compared to adjacent healthy tissues (p < .05). In addition, the expression levels of miR-181a in tumor tissues were strongly correlated with patients' age, tumor size, clinical stage, cancer grade, and lymph node metastasis (p < .05). Our findings highlight new insights into understanding the role of miR-181a in the pathogenesis of osteosarcoma. However, further studies are needed to elucidate miRNA as therapeutic targets for osteosarcoma.

Interplay between programmed death-ligand 1 and non-coding RNAs

Programmed death-ligand 1 (PD-L1) is a transmembrane protein with essential roles in the suppression of adaptive immune responses. As an immune checkpoint molecule, PD-L1 can be exploited by cancer cells to evade the anti-tumor attacks initiated by the immune system. Thus, blockade of the PD1/PD-L1 axis can eliminate the suppressive signals and release the antitumor immune responses. Identification of the underlying mechanisms of modulation of the activity of the PD1/PD-L1 axis would facilitate the design of more efficacious therapeutic options and better assignment of patients for each option. Recent studies have confirmed the interactions between miRNAs/lncRNAs/circ-RNAs and the PD1/PD-L1 axis. In the current review, we give a summary of interactions between these transcripts and PD-L1 in the context of cancer. We also overview the consequences of these interactions in the determination of the response of patients to anti-cancer drugs.

Immune checkpoints in osteosarcoma: Recent advances and therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor and is associated with a high risk of recurrence and distant metastasis. Effective treatment for osteosarcoma, especially advanced osteosarcoma, has stagnated over the past four decades. The advent of immune checkpoint inhibitor (ICI) has transformed the treatment paradigm for multiple malignant tumor types and indicated a potential therapeutic strategy for osteosarcoma. In this review, we discuss recent advances in immune checkpoints, including programmed cell death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1), and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and their related ICIs for osteosarcoma treatment. We present the main existing mechanisms of resistance to ICIs therapy in osteosarcoma. Moreover, we summarize the current strategies for improving the efficacy of ICIs in osteosarcoma and address the potential predictive biomarkers of ICIs treatment in osteosarcoma.

Assessment of MicroRNAs Associated with Tumor Purity by Random Forest Regression

Simple Summary

Cancer is a disease with high mortality and recurrence rates. To understand cancer biology, it is important to accurately determine the proportion of tumor and non-tumor cells in tumor tissues. In this study, the proportion of tumor cells in tumor tissues was predicted using miRNA expression data that had not been sufficiently studied before. Using a random forest regression model, the tumor purity was predicted accurately, and subsequent investigations into the association between the informative microRNAs and tumor purity could be conducted.

Abstract

Tumor purity refers to the proportion of tumor cells in tumor tissue samples. This value plays an important role in understanding the mechanisms of the tumor microenvironment. Although various attempts have been made to predict tumor purity, attempts to predict tumor purity using miRNAs are still lacking. We predicted tumor purity using miRNA expression data for 16 TCGA tumor types using random forest regression. In addition, we identified miRNAs with high feature-importance scores and examined the extent of the change in predictive performance using informative miRNAs. The predictive performance obtained using only 10 miRNAs with high feature importance was close to the result obtained using all miRNAs. Furthermore, we also found genes targeted by miRNAs and confirmed that these genes were mainly related to immune and cancer pathways. Therefore, we found that the miRNA expression data could predict tumor purity well, and the results suggested the possibility that 10 miRNAs with high feature importance could be used as potential markers to predict tumor purity and to help improve our understanding of the tumor microenvironment.

Thrombospondin-1 induced programmed death-ligand 1-mediated immunosuppression by activating the STAT3 pathway in osteosarcoma

Thrombospondin‐1 (TSP1) is generally assumed to suppress the growth of osteosarcoma through inhibiting angiogenesis; however, it is unclear whether TSP1 could affect the antitumor immunity against osteosarcoma. We aimed to explore the immune‐related tumor‐promoting effects of TSP1 and decipher its underlying mechanism. First, we identified that TSP1 regulated programmed death‐ligand 1 (PD‐L1) expression, which was related to the CD8⁺ T cells anergy in osteosarcoma cells. The exact role of PD‐L1 in the immunosuppressive effect of TSP1 was then further confirmed by the addition of the PD‐L1 neutralizing Ab. With the addition of PD‐L1 neutralizing Abs during cocultivation, the inhibition of CD8⁺ T cells was abolished to a certain extent. Further mechanistic investigations showed that TSP1‐induced PD‐L1 upregulation was achieved by activation of the signal transducer and activator of transcription 3 (STAT3) pathway. In vivo experiments also indicated that TSP1 overexpression could promote the growth of primary lesions, whereas TSP1 knockdown effectively inhibits the growth of the primary lesion as well as lung metastasis by restoring the antitumor immunity. Thrombospondin‐1 knockdown combined with PD‐L1 neutralizing Ab achieved a more pronounced antitumor effect. Taken together, our study showed that TSP1 upregulates PD‐L1 by activating the STAT3 pathway and, therefore, impairs the antitumor immunity against osteosarcoma.

Various Uses of PD1/PD-L1 Inhibitor in Oncology: Opportunities and Challenges

The occurrence and development of cancer are closely related to the immune escape of tumor cells and immune tolerance. Unlike previous surgical, chemotherapy, radiotherapy and targeted therapy, tumor immunotherapy is a therapeutic strategy that uses various means to stimulate and enhance the immune function of the body, and ultimately achieves the goal of controlling tumor cells.With the in-depth understanding of tumor immune escape mechanism and tumor microenvironment, and the in-depth study of tumor immunotherapy, immune checkpoint inhibitors represented by Programmed Death 1/Programmed cell Death-Ligand 1(PD-1/PD-L1) inhibitors are becoming increasingly significant in cancer medication treatment. employ a variety of ways to avoid detection by the immune system, a single strategy is not more effective in overcoming tumor immune evasion and metastasis. Combining different immune agents or other drugs can effectively address situations where immunotherapy is not efficacious, thereby increasing the chances of success and alternative access to alternative immunotherapy. Immune combination therapies for cancer have become a hot topic in cancer treatment today. In this paper, several combination therapeutic modalities of PD1/PD-L1 inhibitors are systematically reviewed. Finally, an analysis and outlook are provided in the context of the recent advances in combination therapy with PD1/PD-L1 inhibitors and the pressing issues in this field.

MicroRNA-519d-3p antagonizes osteosarcoma resistance against cisplatin by targeting PD-L1

Accumulating evidence indicates that a ligand of programmed cell death receptor-1 (PD-L1) participates in the progression and recurrence of multiple malignancies, including osteosarcoma. Nevertheless, the role of PD-L1 in chemoresistance development is not fully understood. In the current study, we aim to clarify the interaction of miR-519d-3p and PD-L1 in the development of cisplatin resistance. Immunohistochemistry, quantitative reverse-transcription polymerase reaction, and Western blot were used to evaluate PD-L1 expression. MTT and transwell migration assays were used to measure cell growth and motility, respectively. ENCORI, miRCode, and miRDB databases were recruited to predict candidate miRNAs targeting PD-L1. The binding sequences of miR-519d-3p and PD-L1 3' untranslated region were identified by dual-luciferase reporter and RNA immunoprecipitation assays. Flow cytometric analysis was conducted to measure the cycle distribution and cell apoptosis. Metastatic mouse models were generated with cisplatin-resistant sublines by intravenous injection. We found that PD-L1 expression was positively correlated to cisplatin resistance and metastasis, whereas miR-519d-3p expression was reduced in cisplatin-resistant specimens and was negatively correlated to cisplatin resistance and metastasis of osteosarcoma. We demonstrated that miR-519d-3p overexpression reversed cisplatin resistance, induced G1/S phase arrest and apoptosis. In addition, we proved that miR-519d-3p inhibited lung metastasis by establishing cisplatin-resistant MG63 metastatic xenograft models. The present findings suggest that miR-519d-3p/PD-L1 axis is a novel signaling pathway contributing to cisplatin resistance. Our study provides new clues for curing refractory osteosarcoma beyond immune checkpoint inhibitors.

Identification of cluster of differentiation molecule-associated microRNAs as potential therapeutic targets for gastrointestinal cancer immunotherapy

BACKGROUND

Cluster of differentiation molecules are markers of immune cells that have been identified as a potential immunotherapeutic target for cancer treatment. MicroRNAs are small non-coding RNAs that act as tumor suppressors or oncogenes whose importance in diagnosis, prognosis, and treatment of gastric and colorectal cancers has been widely reported. However, their association with cluster of differentiation molecules in gastrointestinal cancers has not been well studied. Therefore, our study aimed to analyze the relationship between microRNAs and cluster of differentiation molecules in gastrointestinal cancers, and to identify cluster of differentiation molecule-associated microRNAs as prognostic biomarkers for gastrointestinal cancer patients.

METHODS

Targetscan, Starbase, DIANA microT, and miRDB were used to investigate microRNA profiles that might be correlated with cluster of differentiation molecules in gastrointestinal cancers. Moreover, The Cancer Genome Atlas data analysis was used to investigate the association between cluster of differentiation molecules and microRNA expression in patients with gastric, colon, rectal, pancreatic, and esophageal cancers. The Kaplan-Meier plotter was used to identify the association between overall survival and cluster of differentiation molecule-associated microRNA expression in gastrointestinal cancer patients.

RESULTS

miR-200a, miR-559, and miR-1236 were negatively associated with CD86, CD81, and CD160, respectively, in almost all types of gastrointestinal cancers, which were further verified in the in vitro studies by transfecting microRNA mimics in gastric cancer, colon cancer, pancreatic, and esophageal cell lines.

CONCLUSION

Our study showed that miR-200a, miR-1236, and miR-559 are identified as cluster of differentiation-associated microRNAs in gastrointestinal cancers, providing a novel perspective to identify new therapeutic targets for cancer immunotherapy in gastrointestinal cancer patients.

Targeting autophagy enhances atezolizumab-induced mitochondria-related apoptosis in osteosarcoma

In this study, we identified the multifaceted effects of atezolizumab, a specific monoclonal antibody against PD-L1, in tumor suppression except for restoring antitumor immunity, and investigated the promising ways to improve its efficacy. Atezolizumab could inhibit the proliferation and induce immune-independent apoptosis of osteosarcoma cells. With further exploration, we found that atezolizumab could impair mitochondria of osteosarcoma cells, resulting in increased release of reactive oxygen species and cytochrome-c, eventually leading to mitochondrial-related apoptosis via activating JNK pathway. Nevertheless, the excessive release of reactive oxygen species also activated the protective autophagy of osteosarcoma cells. Therefore, when we combined atezolizumab with autophagy inhibitors, the cytotoxic effect of atezolizumab on osteosarcoma cells was significantly enhanced in vitro. Further in vivo experiments also confirmed that atezolizumab combined with chloroquine achieved the most significant antitumor effect. Taken together, our study indicates that atezolizumab can induce mitochondrial-related apoptosis and protective autophagy independently of the immune system, and targeting autophagy is a promising combinatorial approach to amplify its cytotoxicity.

The Updated Status and Future Direction of Immunotherapy Targeting B7-H1/PD-1 in Osteosarcoma

Although the mortality rate of osteosarcoma (OS) patients has improved, there are still many unsolved problems concerning how to reduce recurrence and metastasis. In the tumor microenvironment, immune escape plays a more important role in tumor progression and development. Many costimulatory molecules of the B7 family have been reported to be involved in regulating immunological interactions between OS cells and immune cells. Among these molecules, B7-H1 and its receptor, programmed death-1 (PD-1), have been the focus of the fields of tumor immunology and have been recently applied in clinical trials of therapies for several solid tumors. These therapies, referred to as B7-H1/PD-1 checkpoint blockade therapies, are designed to block the interaction between the two molecules. Although the mechanism has been reported in some malignancies, the specific impact of B7-H1/PD-1 expression on OS has not been well defined. Here, we review the expression, function, and regulatory mechanism of the B7-H1/PD-1 axis in OS and introduce and compare the advantages and disadvantages of B7-H1/PD-1 immunotherapies in OS.

Regulation of PD-L1 expression in the tumor microenvironment

Programmed death-ligand 1 (PD-L1) on cancer cells engages with programmed cell death-1 (PD-1) on immune cells, contributing to cancer immune escape. For multiple cancer types, the PD-1/PD-L1 axis is the major speed-limiting step of the anti-cancer immune response. In this context, blocking PD-1/PD-L1 could restore T cells from exhausted status and eradicate cancer cells. However, only a subset of PD-L1 positive patients benefits from α-PD-1/PD-L1 therapies. Actually, PD-L1 expression is regulated by various factors, leading to the diverse significances of PD-L1 positivity. Understanding the mechanisms of PD-L1 regulation is helpful to select patients and enhance the treatment effect. In this review, we focused on PD-L1 regulators at the levels of transcription, post-transcription, post-translation. Besides, we discussed the potential applications of these laboratory findings in the clinic.

Immunotherapy for osteosarcoma: Fundamental mechanism, rationale, and recent breakthroughs

Osteosarcoma (OS) is the most common primary malignancy of the bone and has a high propensity for local invasion and metastasis. Although combining surgery with chemotherapy has immensely improved the outcomes of osteosarcoma patients, the prognosis of metastatic or recurrent osteosarcomas is still unsatisfactory. Immunotherapy has proven to be a promising therapeutic strategy against human malignancies and improved understanding of the immune response to OS, and biomarker development has increased the number of patients who benefit from immunotherapies in recent years. Here, we review recent advances in immunotherapy in osteosarcoma and discuss the mechanisms and status of immunotherapies in both preclinical and clinical trials as well as future therapies on the horizon. These advances may pave the way for novel treatments requisite for patients with osteosarcoma in need of new therapies.

Role of microRNAs in the crosstalk between osteosarcoma cells and the tumour microenvironment

Osteosarcoma (OS) is the most common primary bone tumour, with a peak incidence in adolescents, and the five-year survival rate of patients with metastasis or recurrence is much lower than that of patients without metastasis and recurrence. OS is initiated and develops in a complex tumour microenvironment (TME) that contains many different components, such as osteoblasts, osteoclasts, mesenchymal stem cells, fibroblasts, immune cells, extracellular matrix (ECM), extracellular vesicles, and cytokines. The extensive interaction between OS and the TME underlies OS progression. Therefore, rather than targeting OS cells, targeting the key factors in the TME may yield novel therapeutic approaches. MicroRNAs (miRNAs) play multiple roles in the biological behaviours of OS, and recent studies have implied that miRNAs are involved in mediating the communication between OS cells and the surrounding TME. Here, we review the TME landscape and the miRNA dysregulation of OS, describe the role of the altered TME in OS development and highlight the role of miRNA in the crosstalk between OS cells and the TME.

MicroRNA-208a-3p promotes osteosarcoma progression via targeting PTEN

Osteosarcoma (OS) is a malignant bone tumor with a poor prognosis. Accumulated evidence has suggested that microRNAs (miRNAs/miRs) may function as either oncogenes or tumor suppressors, which are associated with tumorigenesis and the progression of different types of cancer. In the present study, the role of miR-208a-3p in OS was investigated. The expression levels of miR-208a-3p in OS tissues and cell lines were determined via reverse transcription-quantitative PCR (RT-qPCR). MTT and colony formation assays were performed to verify the proliferation rate of OS cells. In addition, the effects of miR-208a-3p on the migration and invasion of OS cells were revealed using wound-healing and Transwell assays, respectively. Furthermore, the association between miR-208a-3p and phosphatase and tensin homolog (PTEN) 3'-untranslated region was determined via luciferase reporter assays, western blot and RT-qPCR analysis. The results indicated that miR-208a-3p was upregulated in OS tissues and cell lines compared with adjacent normal tissues and human osteoblastic cells, respectively. miR-208a-3p overexpression promoted and miR-208a-3p knockdown inhibited OS cells proliferation and metastatic potential. Additionally, PTEN was validated as a direct target of miR-208a-3p and its expression was negatively associate with that of miR-208a-3p in OS cells. Taken together, these results may suggest that miR-208a-3p promoted OS cells proliferation and metastatic potential via targeting PTEN. Therefore, miR-208a-3p may be considered as a diagnostic biomarker for OS.

Development of a prognostic gene signature based on an immunogenomic infiltration analysis of osteosarcoma

Osteosarcoma is the most common primary malignant bone tumour predominantly occurring in children and adolescents with a high tendency of local invasion and early metastases. Currently, tumour immune microenvironment (TME) is becoming the focus of studying of malignant tumours.. However, no sound evidence shows a specific immune molecular target in osteosarcoma. We downloaded the gene expression profile and clinical data of osteosarcoma from the TARGET portal, and extracted and normalized via R software. Then, the immune cell infiltration assessed by CIBERSORT and ESTIMATE algorithms. Three survival‐related immune cells and immune score were obtained via Kaplan‐Meier survival analysis, and 232 immune‐related genes were obtained as candidate genes. Enrichment and protein‐protein interaction co‐expression analyses were performed to identify 13 hub genes. Lastly, a seven gene prognostic signature was identified by univariate and multivariate Cox regression analyses. More importantly, our validations and TIMER algorithm suggested this immune‐related prognostic signature a good predictive tool. Our findings have provided novel insights that could demonstrate new targets of immunotherapy in osteosarcoma.

PTEN in osteosarcoma: Recent advances and the therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor, predominantly occurring in children and adolescents. Despite treated with surgery and neoadjuvant chemotherapy, osteosarcoma has a high potential of local recurrence and lung metastasis. Overall survival rates for osteosarcoma have plateaued in the past four decades, therefore, identification of novel targets and development of more effective treatment strategies are urgent. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that negatively regulates the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway. Over half of clinical osteosarcoma samples presented loss or low expression of PTEN, which usually indicated an advanced stage of tumor and a poor prognosis. The expression of PTEN is regulated by epigenetic silence, transcription regulation, post-translational modifications, and protein interactions in osteosarcoma. Therefore, explicating regulations to restore the anti-tumor function of PTEN might provide novel targeted therapies for osteosarcoma. Preclinical evidence suggested directly targeting the altered PTEN in osteosarcoma was promising. Current clinical application of PTEN related therapies in osteosarcoma are PI3K/mTOR inhibitors, and these drugs have shown the favorable efficacy in patients with advanced osteosarcoma.

Characterization of PD-1/PD-L1 Immune Checkpoint Expression in Osteosarcoma

Recent data have suggested that PD-1 and PD-L1 are involved in osteosarcoma (OS) pathogenesis; however, their contributions are not well-established. Here, the PD-1/PD-L1 expression was evaluated in (OS) cases. Preoperative needle biopsy specimens were obtained from 16 patients with OS. Immunostaining for CD4, CD8, PD-1, and PD-L1 was performed on pathological specimens. Clinical parameters, including age, tumor size, preoperative alkaline phosphatase (ALP) level, standardized uptake value (SUV)-max level, and survival rate, were compared between PD-1/PD-L1-positive and -negative groups. CD4-, CD8-, PD-1-, and PD-L1-positive rates among all specimens were 75%, 75%, 18.7%, and 62.5%, respectively. The rates of co-expression of CD4 and CD8 with PD-L1 were 56.2% and 50%, respectively. Tumors were significantly larger in PD-L1-negative cases than in PD-L1-positive cases. Age, size and ALP and SUV-max levels did not differ significantly between PD-1/PD-L1-positive and -negative cases. The 3-year survival rates did not differ significantly between PD-1-positive and -negative cases or between PD-L1-positive and -negative cases. However, the occurrence of cancer-related events, including recurrence, metastasis, and death was associated with the PD-1-negative and PD-L1-positive status. The PD-1/PD-L1 checkpoint is likely involved in the immune microenvironment in OS and may be involved in the occurrence of cancer-related events.

Inhibition of miRNA-152-3p enhances diabetic wound repair via upregulation of PTEN

Diabetic foot ulcer (DFU) is a major complication of diabetes in the elderly population. The aim of this study was to investigate the potential mechanism of DFU at the molecular level and explore a feasible therapy for it. Using data from the Gene Expression Omnibus (GEO) database, we found that phosphatase and tensin homolog (PTEN) is differentially expressed between diabetic patients and those without diabetes. We also found that PTEN expression is regulated by glucose stimulation. In addition, decreased function of human umbilical vein endothelial cells (HUVECs) was found to be associated with reduction of PTEN. We identified microRNA-152-3p (miR-152-3p) to be a putative upstream negative regulator of PTEN, and in vivo and in vitro results indicated that miR-152-3p antagonist could restore HUVEC function and accelerate wound repair. Thus, miR-152-3p-induced downregulation of PTEN appears responsible for the delayed wound healing in DFU, and miR-152-3p inhibition may effectively accelerate wound repair, thereby providing a potential target for DFU therapy.

Long Non-Coding RNA 691 Regulated PTEN/PI3K/AKT Signaling Pathway in Osteosarcoma Through miRNA-9-5p

Background

Large amounts of researches indicate that non-coding RNAs play a crucial role in many malignancies. However, the potential mechanisms of non-coding RNAs involved in osteosarcoma tumorigenesis remain elusive.

Materials and Methods

The expression of long non-protein coding RNA 691 (lncRNA 691) in cell lines and paired osteosarcoma tissues was compared by qRT-PCR assay. Then, we explored the tumor suppressor function of lncRNA 691 with MTS and colony formation assay. Flow cytometry results showed lncRNA 691 can enhance cell apoptosis. Then, we predicted and verified the negative regulation relationship with miRNA and the miRNA’s target gene. Lastly, we revealed the tumorigenesis function of lncRNA-691/miRNA/target gene axis in osteosarcoma.

Results

In our study, we disclosed that lncRNA 691 had low expression levels in osteosarcoma cell lines and tissues. Overexpression of lncRNA 691 could suppress the cell proliferation and induce cell apoptosis in MG-63 cell line. Then, bioinformatics analyses were performed and miR-9-5p was found to negatively regulate the lncRNA 691 expression and promote the osteosarcoma tumorigenesis in vitro. PTEN was predicted as the target gene of miR-9-5p. Luciferase reporter assay and RIP assay demonstrated the regulatory network of lncRNA 691/miR-9-5p/PTEN. We revealed that PTEN was downregulated by the overexpression of miR-9-5p and upregulated by the overexpression of lncRNA 691. At last, the apoptosis-associated protein of the lncRNA 691/miR-9-5p/PTEN/PI3K/AKT was further demonstrated.

Conclusion

LncRNA 691/miR-9-5p could regulate the tumorigenesis by regulating the PTEN/PI3K/AKT signal pathway in osteosarcoma.