A Systematic Review on the Therapeutic Potentiality of PD-L1-Inhibiting MicroRNAs for Triple-Negative Breast Cancer: Toward Single-Cell Sequencing-Guided Biomimetic Delivery

The programmed death-ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) is a well-established inhibitory immune checkpoint axis in triple-negative breast cancer (TNBC). Growing evidence indicates that tumoral PD-L1 can lead to TNBC development. Although conventional immune checkpoint inhibitors have improved TNBC patients’ prognosis, their effect is mainly focused on improving anti-tumoral immune responses without substantially regulating oncogenic signaling pathways in tumoral cells. Moreover, the conventional immune checkpoint inhibitors cannot impede the de novo expression of oncoproteins, like PD-L1, in tumoral cells. Accumulating evidence has indicated that the restoration of specific microRNAs (miRs) can downregulate tumoral PD-L1 and inhibit TNBC development. Since miRs can target multiple mRNAs, miR-based gene therapy can be an appealing approach to inhibit the de novo expression of oncoproteins, like PD-L1, restore anti-tumoral immune responses, and regulate various intracellular singling pathways in TNBC. Therefore, we conducted the current systematic review based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) to provide a comprehensive and unbiased synthesis of currently available evidence regarding the effect of PD-L1-inhibiting miRs restoration on TNBC development and tumor microenvironment. For this purpose, we systematically searched the Cochrane Library, Embase, Scopus, PubMed, ProQuest, Web of Science, Ovid, and IranDoc databases to obtain the relevant peer-reviewed studies published before 25 May 2021. Based on the current evidence, the restoration of miR-424-5p, miR-138-5p, miR-570-3p, miR-200c-3p, miR-383-5p, miR-34a-5p, miR-3609, miR-195-5p, and miR-497-5p can inhibit tumoral PD-L1 expression, transform immunosuppressive tumor microenvironment into the pro-inflammatory tumor microenvironment, inhibit tumor proliferation, suppress tumor migration, enhance chemosensitivity of tumoral cells, stimulate tumor apoptosis, arrest cell cycle, repress the clonogenicity of tumoral cells, and regulate various oncogenic signaling pathways in TNBC cells. Concerning the biocompatibility of biomimetic carriers and the valuable insights provided by the single-cell sequencing technologies, single-cell sequencing-guided biomimetic delivery of these PD-L1-inhibiting miRs can decrease the toxicity of traditional approaches, increase the specificity of miR-delivery, enhance the efficacy of miR delivery, and provide the affected patients with personalized cancer therapy.

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From Oncogenic Signaling Pathways to Single-Cell Sequencing of Immune Cells: Changing the Landscape of Cancer Immunotherapy

Molecules ◽

10.3390/molecules26082278 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2278

Author(s):

Afshin Derakhshani ◽

Zeinab Rostami ◽

Hossein Safarpour ◽

Mahdi Abdoli Shadbad ◽

Niloufar Sadat Nourbakhsh ◽

...

Keyword(s):

Single Cell ◽

Signaling Pathways ◽

Immune Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Cancer Development ◽

Immune Checkpoints ◽

Single Cell Sequencing ◽

Increased Risk

Over the past decade, there have been remarkable advances in understanding the signaling pathways involved in cancer development. It is well-established that cancer is caused by the dysregulation of cellular pathways involved in proliferation, cell cycle, apoptosis, cell metabolism, migration, cell polarity, and differentiation. Besides, growing evidence indicates that extracellular matrix signaling, cell surface proteoglycans, and angiogenesis can contribute to cancer development. Given the genetic instability and vast intra-tumoral heterogeneity revealed by the single-cell sequencing of tumoral cells, the current approaches cannot eliminate the mutating cancer cells. Besides, the polyclonal expansion of tumor-infiltrated lymphocytes in response to tumoral neoantigens cannot elicit anti-tumoral immune responses due to the immunosuppressive tumor microenvironment. Nevertheless, the data from the single-cell sequencing of immune cells can provide valuable insights regarding the expression of inhibitory immune checkpoints/related signaling factors in immune cells, which can be used to select immune checkpoint inhibitors and adjust their dosage. Indeed, the integration of the data obtained from the single-cell sequencing of immune cells with immune checkpoint inhibitors can increase the response rate of immune checkpoint inhibitors, decrease the immune-related adverse events, and facilitate tumoral cell elimination. This study aims to review key pathways involved in tumor development and shed light on single-cell sequencing. It also intends to address the shortcomings of immune checkpoint inhibitors, i.e., their varied response rates among cancer patients and increased risk of autoimmunity development, via applying the data from the single-cell sequencing of immune cells.

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Oncogenic signaling pathways associated with immune evasion and resistance to immune checkpoint inhibitors in cancer

Seminars in Cancer Biology ◽

10.1016/j.semcancer.2019.11.011 ◽

2020 ◽

Vol 65 ◽

pp. 51-64 ◽

Cited By ~ 8

Author(s):

Yoshie Kobayashi ◽

Seung-Oe Lim ◽

Hirohito Yamaguchi

Keyword(s):

Signaling Pathways ◽

Immune Evasion ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Oncogenic Signaling ◽

Oncogenic Signaling Pathways

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Therapeutic checkpoint targets: Evaluation of co-expression profiles in individual tumor and immune cells in the tumor microenvironment of FFPE tissue.

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.5_suppl.176 ◽

2018 ◽

Vol 36 (5_suppl) ◽

pp. 176-176

Author(s):

Annelies Laeremans ◽

Na Li ◽

Jeff Kim ◽

Xiao-Jun Ma ◽

Emily Park

Keyword(s):

Tumor Microenvironment ◽

Single Cell ◽

Immune Cells ◽

Immune Checkpoint ◽

Checkpoint Inhibitors ◽

Expression Profiles ◽

Predictive Biomarkers ◽

Immune Checkpoint Blockade ◽

Durable Response

176 Background: Interactions between tumor and immune cells in the tumor microenvironment (TME) play a key role in tumor progression and treatment response with accumulating evidence indicating a crucial role for tumor infiltrating immune cells. Although infiltrating cytotoxic T lymphocytes (CTLs) have been correlated with improved clinical outcome, they are ineffective in eradicating tumors due to their inhibition by immune checkpoint molecules. Immune checkpoint inhibitors have demonstrated therapeutic efficacy and durable response for several tumor types including non-small cell lung cancer (NSCLC). However, the majority of patients are resistant or relapse after initial response. Characterizing the TME for checkpoint expression with single-cell and spatial resolution can provide critical insight into new immunotherapeutic strategies and identify new predictive biomarkers for stratifying and identifying patients most likely to benefit from immunotherapy including PD-1/PD-L1 immune checkpoint blockade. Methods: Using RNAscope in situ hybridization, we evaluated in situ co-expression profiles of therapeutic checkpoint targets at single-cell level in the TME of 56 archived NSCLC FFPE tissues. Results: Checkpoint molecules including PD1, PD-L1, PD-L2, TIM3, LAG3, CTLA-4 and GITR were visualized in a highly specific and sensitive manner in individual cells within tissue morphological context. Multiple checkpoint molecules were detected in the same immune environment, especially in highly inflamed tumors. In addition to PD-L1, tumor cell-intrinsic expression of PD1, TIM3, LAG3, and PD-L2 was observed in a subset of samples. Furthermore, co-expression of therapeutic checkpoint targets including PD1, LAG3, and TIM3 was observed in infiltrating immune cells and tumor cells. Conclusions: Single-cell co-expression profiles of checkpoint molecules could shed light on how cancer cells evade the host immune surveillance and develop resistance against checkpoint blockades. Also, they could reveal valuable insights into combinatorial therapies for checkpoint markers co-expressed by the patient’s immune cells in the TME.

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IMMU-01. SINGLE CELL SEQUENCING OF MELANOMA BRAIN METASTASES UNVEILS HETEROGENEITY OF THE TUMOR MICROENVIRONMENT IN RESPONSE TO IMMUNE CHECKPOINT BLOCKADE

Neuro-Oncology ◽

10.1093/neuonc/noaa215.432 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii104-ii104

Author(s):

Christopher Alvarez-Breckenridge ◽

Samuel Markson ◽

Jackson Stocking ◽

Matt Lastrapes ◽

Naema Nayyar ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Microenvironment ◽

Brain Metastases ◽

Single Cell ◽

Immune Checkpoint ◽

Heterogeneous Distribution ◽

Single Cell Sequencing ◽

Melanoma Brain Metastases ◽

The Brain

Abstract Immune checkpoint inhibitors (ICI) have revolutionized oncologic treatment for metastatic melanoma. With improved systemic control, there has been increasing prevalence of patients with brain metastases. Recent evidence has demonstrated intracranial responses in a subset of these patients treated with ICI. We hypothesize that the response to ICI in melanoma brain metastases (MBM) is reflective of unique features within the tumor microenvironment of the brain. A cohort of 27 patients, encompassing 8 pre- and 19 post-immunotherapy MBM underwent single cell RNA sequencing (Smart-Seq2). The cohort includes patients with longitudinal cranial resections and simultaneously resected, spatially distinct tumors. Each tumor underwent unsupervised transcriptomic analysis, differential gene expression, inferred copy number variation, and T-cell receptor (TCR) clonotyping. Published extracranial melanoma single cell datasets were used to compare the tumor microenvironment of the brain and periphery in response to ICI. A total of 14,027 cells (6,189 malignant, 7,838 non-malignant) were sequenced. Brain metastases demonstrated a heterogeneous distribution of macrophage states. Intracranial macrophages were found to be more tumor-supportive than their extracranial counterparts. MBM also included a distribution of reactive neutrophils and astrocytes. Analysis across pre- and post-treatment MBM demonstrated an increase in clonally expanded T cells in patients responding to ICI. Across longitudinal brain metastases collected from the same patients, there was evidence of identical T cell clones across timepoints and locations. Single cell sequencing of MBM provides insights into the cellular composition of the tumor and microenvironment. Our data suggest the cellular heterogeneity within MBM is unique when compared to extracranial disease. Additionally, T cell clonal expansion is found following ICI and T cells of the same clonotype infiltrate spatially and temporally separated brain metastases. These findings raise potential therapeutic implications as we learn to target the differential features of the innate and adaptive immune system within brain metastases and their extracranial counterparts.

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Emerging Trends for Radio-Immunotherapy in Rectal Cancer

Cancers ◽

10.3390/cancers13061374 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1374

Author(s):

Claudia Corrò ◽

Valérie Dutoit ◽

Thibaud Koessler

Keyword(s):

Rectal Cancer ◽

Tumor Microenvironment ◽

Immune Checkpoint ◽

Checkpoint Inhibitors ◽

Predictive Biomarkers ◽

Tumor Infiltrating Lymphocytes ◽

T Cell Infiltration ◽

Emerging Trends ◽

Tumor Mutational Burden ◽

Microsatellite Stability

Rectal cancer is a heterogeneous disease at the genetic and molecular levels, both aspects having major repercussions on the tumor immune contexture. Whilst microsatellite status and tumor mutational load have been associated with response to immunotherapy, presence of tumor-infiltrating lymphocytes is one of the most powerful prognostic and predictive biomarkers. Yet, the majority of rectal cancers are characterized by microsatellite stability, low tumor mutational burden and poor T cell infiltration. Consequently, these tumors do not respond to immunotherapy and treatment largely relies on radiotherapy alone or in combination with chemotherapy followed by radical surgery. Importantly, pre-clinical and clinical studies suggest that radiotherapy can induce a complete reprograming of the tumor microenvironment, potentially sensitizing it for immune checkpoint inhibition. Nonetheless, growing evidence suggest that this synergistic effect strongly depends on radiotherapy dosing, fractionation and timing. Despite ongoing work, information about the radiotherapy regimen required to yield optimal clinical outcome when combined to checkpoint blockade remains largely unavailable. In this review, we describe the molecular and immune heterogeneity of rectal cancer and outline its prognostic value. In addition, we discuss the effect of radiotherapy on the tumor microenvironment, focusing on the mechanisms and benefits of its combination with immune checkpoint inhibitors.

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P02.10 FocuSCOPE: a single cell, multi-omics solution to simultaneously analyze tumor variants and microenvironment

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-itoc8.22 ◽

2021 ◽

Vol 9 (Suppl 1) ◽

pp. A12.1-A12

Author(s):

Y Arjmand Abbassi ◽

N Fang ◽

W Zhu ◽

Y Zhou ◽

Y Chen ◽

...

Keyword(s):

Gene Expression ◽

Tumor Microenvironment ◽

Single Cell ◽

High Throughput ◽

Immune Cells ◽

Genetic Variants ◽

Expression Profiles ◽

Single Cells ◽

Gene Expression Profiles ◽

Single Cell Sequencing

Recent advances of high-throughput single cell sequencing technologies have greatly improved our understanding of the complex biological systems. Heterogeneous samples such as tumor tissues commonly harbor cancer cell-specific genetic variants and gene expression profiles, both of which have been shown to be related to the mechanisms of disease development, progression, and responses to treatment. Furthermore, stromal and immune cells within tumor microenvironment interact with cancer cells to play important roles in tumor responses to systematic therapy such as immunotherapy or cell therapy. However, most current high-throughput single cell sequencing methods detect only gene expression levels or epigenetics events such as chromatin conformation. The information on important genetic variants including mutation or fusion is not captured. To better understand the mechanisms of tumor responses to systematic therapy, it is essential to decipher the connection between genotype and gene expression patterns of both tumor cells and cells in the tumor microenvironment. We developed FocuSCOPE, a high-throughput multi-omics sequencing solution that can detect both genetic variants and transcriptome from same single cells. FocuSCOPE has been used to successfully perform single cell analysis of both gene expression profiles and point mutations, fusion genes, or intracellular viral sequences from thousands of cells simultaneously, delivering comprehensive insights of tumor and immune cells in tumor microenvironment at single cell resolution.Disclosure InformationY. Arjmand Abbassi: None. N. Fang: None. W. Zhu: None. Y. Zhou: None. Y. Chen: None. U. Deutsch: None.

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M6a Regulator-Associated Methylation Modification Patterns Shape Tumor Microenvironment Characteristics in Hepatocellular Carcinoma

10.21203/rs.3.rs-778749/v1 ◽

2021 ◽

Author(s):

Bobin Ning ◽

Yonggan Xue ◽

Hongyi Liu ◽

Hongyu Sun ◽

Baoqing Jia

Keyword(s):

Hepatocellular Carcinoma ◽

Tumor Microenvironment ◽

Single Cell ◽

Signaling Pathways ◽

Principal Component ◽

Unsupervised Clustering ◽

Survival Prediction ◽

Multiple Perspectives ◽

Single Cell Sequencing ◽

Survival Expectations

Abstract Although substantial achievements in the tumor microenvironment (TME) of hepatocellular carcinoma (HCC) have led to fundamental improvements both in the basic research and clinical management, the potential mechanisms and regulatory relationships between m6A regulators and the TME are still unknown. We first conducted unsupervised clustering on the samples according to the core m6A expression, and then compared the signaling pathways, differential genes (DEGs), and TME between the m6A phenotypes, and re-validated the relationship between m6A regulators and TME by single cell sequencing. Then, the geneCluster was obtained by another unsupervised clustering of the DEGs, and the clinical as well as TME traits were evaluated among the geneClusters. Finally, the m6A scores of individual patients were calculated by principal component analysis (PCA) to verify the correlation from multiple perspectives, including survivals, clinical characters, mutations, TME, immunotherapy, and chemotherapy. Through a comprehensive analysis of 729 samples, we classified HCC patients into three m6A clusters and three geneClusters. Each group exhibited remarkable variations in terms of signaling pathways, clinical traits, and survival expectations. Notably, the m6A phenotypes corresponded to three different types of TME, namely immune-inflamed, immune-excluded, and immune-desert, respectively. In addition, the m6A regulator can accurately reflect the individualized microenvironment in HCC, and present supreme expression levels in the stromal microenvironment. However, the m6A score system is able to make accurate predictions not only in terms of clinical traits, survival prediction, and TME mentioned above, but also in the sensitivity of HCC patients to immunotherapy and chemotherapy. This study revealed the uniqueness and pluripotency of m6A regulators in the TME of HCC by combining single-cell sequencing and bulk sequencing. The quantified m6A modification indices were able to accurately predict patient survival expectations, clinical traits, TME, and sensitivity to immunotherapy and chemotherapy.

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Overcoming Resistance to Immune Checkpoint Inhibitors in Head and Neck Squamous Cell Carcinomas

Frontiers in Oncology ◽

10.3389/fonc.2021.596290 ◽

2021 ◽

Vol 11 ◽

Author(s):

Lucas V. dos Santos ◽

Carina M. Abrahão ◽

William N. William

Keyword(s):

Head And Neck ◽

Squamous Cell ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

De Novo ◽

Checkpoint Inhibitors ◽

Acquired Resistance ◽

Clinical Work ◽

Squamous Cell Carcinomas ◽

Clinical Activity

Preclinical data suggest that head and neck squamous cell carcinomas (HNSCC) may evade immune surveillance and induce immunosuppression. One mechanism of immune evasion involves the expression of programmed death ligand-1 (PD-L1) in tumor and immune cells, which is, to date, the only biomarker routinely used in clinical practice to select patients with advanced HNSCCs more likely to benefit from anti-PD-1 therapy. Nonetheless, PD-L1 expression alone incompletely captures the degree of sensitivity of HNSCCs to PD-1 inhibitors. Most patients exposed to anti-PD-1 antibodies do not respond to therapy, suggesting the existence of mechanisms of de novo resistance to immunotherapy. Furthermore, patients that initially respond to PD-1 inhibitors will eventually develop acquired resistance to immunotherapy through mechanisms that have not yet been completely elucidated. In this article, we will provide an overview of the immune landscape of HNSCCs. We will briefly describe the clinical activity of inhibitors of the PD-1/PD-L1 axis in this disease, as well as biomarkers of benefit from these agents that have been identified so far. We will review pre-clinical and clinical work in cancers in general, and in HNSCCs specifically, that have characterized the mechanisms of de novo and acquired resistance to immunotherapy. Lastly, we will provide insights into novel strategies under investigation to overcome resistance to immune checkpoint inhibitors.

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