Using mouse liver cancer models based on somatic genome editing to predict immune checkpoint inhibitor responses

LiverSCA: A comprehensive and user-friendly cell atlas in human hepatocellular carcinoma

We developed a cell atlas named LiverSCA on human liver cancer single-cell RNA sequencing data. It has a user-friendly web interface and comprehensive functionalities aiming to help researchers to make easy access to cellular and molecular landscapes of the tumor microenvironment in liver cancer. LiverSCA includes a complete analytical pipeline that allow mechanistic exploration on a wide variety of functionalities, such as cell clustering, cell annotation, identification of differentially expressed genes, functional enrichment analysis, analysis of cellular crosstalk, and pseudo-time trajectory analysis. Notably, our intuitive web interface allows users, particularly wet-lab researchers, to easily explore and undertake data discovery, without the need to handle any of the raw data.

Interleukin-34-orchestrated tumor-associated macrophage reprogramming is required for tumor immune escape driven by p53 inactivation

As the most frequent genetic alteration in cancer, more than half of human cancers have p53 mutations that cause transcriptional inactivation. However, how p53 modulates the immune landscape to create a niche for immune escape remains elusive. We found that cancer stem cells (CSCs) established an interleukin-34 (IL-34)-orchestrated niche to promote tumorigenesis in p53-inactivated liver cancer. Mechanistically, we discovered that Il34 is a gene transcriptionally repressed by p53, and p53 loss resulted in IL-34 secretion by CSCs. IL-34 induced CD36-mediated elevations in fatty acid oxidative metabolism to drive M2-like polarization of foam-like tumor-associated macrophages (TAMs). These IL-34-orchestrated TAMs suppressed CD8+ T cell-mediated antitumor immunity to promote immune escape. Blockade of the IL-34-CD36 axis elicited antitumor immunity and synergized with anti-PD-1 immunotherapy, leading to a complete response. Our findings reveal the underlying mechanism of p53 modulation of the tumor immune microenvironment and provide a potential target for immunotherapy of cancer with p53 inactivation.

METTL16-SENP3-LTF axis confers ferroptosis resistance and facilitates tumorigenesis in hepatocellular carcinoma

BACKGROUND

Ferroptosis, characterized by iron-dependent lipid peroxidation, emerges as a promising avenue for hepatocellular carcinoma (HCC) intervention due to its tumor susceptibility. RNA N6-methyladenosine (m6A) modification has been involved in several types of regulated cell death. However, the roles and molecular mechanisms of m6A-related regulators in HCC cell ferroptosis remain unclear.

METHODS

By examining a series of m6A modification enzymes upon ferroptosis induction or inhibition, we identified METTL16 as a novel ferroptotic repressor in HCC cells. The roles of METTL16 on ferroptosis and HCC development were investigated in multiple cell lines, human HCC organoids, subcutaneous xenografts and MYC/Trp53-/- HCC model in hepatocyte-specific Mettl16 knockout and overexpression mice. The underlying mechanism was elucidated with MeRIP/RIP-qPCR, luciferase assay, Co-IP assay and Mass Spectrometry. The clinical significance and relevance were evaluated in human samples.

RESULTS

High METTL16 expression confers ferroptosis resistance in HCC cells and mouse models, and promotes cell viability and tumor progression. Mechanistically, METTL16 collaborates with IGF2BP2 to modulate SENP3 mRNA stability in an m6A-dependent manner, and the latter impedes the proteasome-mediated ubiquitination degradation of Lactotransferrin (LTF) via de-SUMOylation. Elevated LTF expression facilitates the chelation of free iron and reduces liable iron pool level. SENP3 and LTF are implicated in METTL16-mediated HCC progression and anti-ferroptotic effects both in vivo and in vitro. Clinically, METTL16 and SENP3 expression were positively correlated, and high METTL16 and SENP3 expression predicts poor prognosis in human HCC samples.

CONCLUSIONS

Our study reveals a new METTL16-SENP3-LTF signaling axis regulating ferroptosis and driving HCC development. Targeting this axis is a promising strategy for sensitizing ferroptosis and against HCC.

The current status and future of targeted-immune combination for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers and the third leading cause of death worldwide. surgery, transarterial chemoembolization (TACE), systemic therapy, local ablation therapy, radiotherapy, and targeted drug therapy with agents such as sorafenib. However, the tumor microenvironment of liver cancer has a strong immunosuppressive effect. Therefore, new treatments for liver cancer are still necessary. Immune checkpoint molecules, such as programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen-4 (CTLA-4), along with high levels of immunosuppressive cytokines, induce T cell inhibition and are key mechanisms of immune escape in HCC. Recently, immunotherapy based on immune checkpoint inhibitors (ICIs) as monotherapy or in combination with tyrosine kinase inhibitors, anti-angiogenesis drugs, chemotherapy agents, and topical therapies has offered great promise in the treatment of liver cancer. In this review, we discuss the latest advances in ICIs combined with targeted drugs (targeted-immune combination) and other targeted-immune combination regimens for the treatment of patients with advanced HCC (aHCC) or unresectable HCC (uHCC), and provide an outlook on future prospects. The literature reviewed spans the last five years and includes studies identified using keywords such as "hepatocellular carcinoma," "immune checkpoint inhibitors," "targeted therapy," "combination therapy," and "immunotherapy".

Current application and future perspective of CRISPR/cas9 gene editing system mediated immune checkpoint for liver cancer treatment

Liver cancer, which is well-known to us as one of human most prevalent malignancies across the globe, poses a significant risk to live condition and life safety of individuals in every region of the planet. It has been shown that immune checkpoint treatment may enhance survival benefits and make a significant contribution to patient prognosis, which makes it a promising and popular therapeutic option for treating liver cancer at the current time. However, there are only a very few numbers of patients who can benefit from the treatment and there also exist adverse events such as toxic effects and so on, which is still required further research and discussion. Fortunately, the clustered regularly interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9) provides a potential strategy for immunotherapy and immune checkpoint therapy of liver cancer. In this review, we focus on elucidating the fundamentals of the recently developed CRISPR/Cas9 technology as well as the present-day landscape of immune checkpoint treatment which pertains to liver cancer. What's more, we aim to explore the molecular mechanism of immune checkpoint treatment in liver cancer based on CRISPR/Cas9 technology. At last, its encouraging and powerful potential in the future application of the clinic is discussed, along with the issues that already exist and the difficulties that must be overcome. To sum up, our ultimate goal is to create a fresh knowledge that we can utilize this new CRISPR/Cas9 technology for the current popular immune checkpoint therapy to overcome the treatment issues of liver cancer.

Engineered small extracellular vesicle-mediated ferroptosis: A new frontier in cancer immunotherapy

Ferroptosis is a novel iron-dependent form of cell death discovered in recent years, characterized by the accumulation of ferrous iron, the production of reactive oxygen species (ROS) through the Fenton reaction, and lipid peroxidation, ultimately leading to the disruption of the antioxidant system and cell membrane damage. Extensive research has found that ferroptosis plays a significant role in regulating tumor cell immune evasion, tumor development, and remodeling the tumor microenvironment. Small Extracellular vesicles (sEVs), carrying various bioactive molecules (ncRNA, DNA, proteins), are key nanoscale mediators of intercellular communication. Increasing evidence confirms that EVs can regulate the ferroptosis pathway in tumors, promoting tumor cell immune evasion and reshaping the tumor microenvironment. This article aims to comprehensively review the key mechanisms by which sEVs mediate ferroptosis in cancer and provide new insights into targeting tumor immunotherapy.

Targeting MMP9 in CTNNB1 mutant hepatocellular carcinoma restores CD8+ T cell-mediated antitumour immunity and improves anti-PD-1 efficacy

OBJECTIVE

The gain of function (GOF) CTNNB1 mutations (CTNNB1 GOF ) in hepatocellular carcinoma (HCC) cause significant immune escape and resistance to anti-PD-1. Here, we aimed to investigate the mechanism of CTNNB1 GOF HCC-mediated immune escape and raise a new therapeutic strategy to enhance anti-PD-1 efficacy in HCC.

DESIGN

RNA sequencing was performed to identify the key downstream genes of CTNNB1 GOF associated with immune escape. An in vitro coculture system, murine subcutaneous or orthotopic models, spontaneously tumourigenic models in conditional gene-knock-out mice and flow cytometry were used to explore the biological function of matrix metallopeptidase 9 (MMP9) in tumour progression and immune escape. Single-cell RNA sequencing and proteomics were used to gain insight into the underlying mechanisms of MMP9.

RESULTS

MMP9 was significantly upregulated in CTNNB1 GOF HCC. MMP9 suppressed infiltration and cytotoxicity of CD8+ T cells, which was critical for CTNNB1 GOF to drive the suppressive tumour immune microenvironment (TIME) and anti-PD-1 resistance. Mechanistically, CTNNB1 GOF downregulated sirtuin 2 (SIRT2), resulting in promotion of β-catenin/lysine demethylase 4D (KDM4D) complex formation that fostered the transcriptional activation of MMP9. The secretion of MMP9 from HCC mediated slingshot protein phosphatase 1 (SSH1) shedding from CD8+ T cells, leading to the inhibition of C-X-C motif chemokine receptor 3 (CXCR3)-mediated intracellular of G protein-coupled receptors signalling. Additionally, MMP9 blockade remodelled the TIME and potentiated the sensitivity of anti-PD-1 therapy in HCC.

CONCLUSIONS

CTNNB1 GOF induces a suppressive TIME by activating secretion of MMP9. Targeting MMP9 reshapes TIME and potentiates anti-PD-1 efficacy in CTNNB1 GOF HCC.

Macrophage hitchhiking for systematic suppression in postablative multifocal HCC

BACKGROUND AND AIMS

HCC, particularly the multifocal HCC, features aggressive invasion and dismal prognosis. Locoregional treatments were often refractory to eliminate tumor tissue, resulting in residual tumor cells persisting and subsequent progression. Owing to problematic delivery to the tumor tissue, systemic therapies, such as lenvatinib (LEN) therapy, show limited clinical benefit in preventing residual tumor progression. Therefore, more advanced strategies for postablative multifocal HCC are urgently needed.

APPROACH AND RESULTS

Motivated by the chemotaxis in tumor penetration of macrophages, we report a strategy named microinvasive ablation-guided macrophage hitchhiking for the targeted therapy toward HCC. In this study, the strategy leverages the natural inflammatory gradient induced by ablation to guide LEN-loaded macrophages toward tumor targeting, which increased by ~10-fold the delivery efficiency of LEN in postablative HCC in vivo. Microinvasive ablation-guided macrophage hitchhiking has demonstrated significant antitumor activity in various HCC models, including the hydrodynamic tail vein injection multifocal HCC mouse model and the orthotopic xenograft HCC rabbit model, systematically inhibiting residual tumor progression after ablation and prolonging the median survival of tumor-bearing mice. The potential antitumor mechanism was explored using techniques such as flow cytometry, ELISA, and immunohistochemistry. We found that the strategy significantly suppressed tumor cell proliferation and neovascularization, and such enhanced delivery of LEN stimulated systemic immune responses and induced durable immune memory.

CONCLUSIONS

The macrophage hitchhiking strategy demonstrates exceptional therapeutic efficacy and biosafety across various species, offering promising prospects for clinical translation in controlling residual tumor progression and improving outcomes following HCC ablation.

CRISPR-Cas9 applications in T cells and adoptive T cell therapies

T cell immunity is central to contemporary cancer and autoimmune therapies, encompassing immune checkpoint blockade and adoptive T cell therapies. Their diverse characteristics can be reprogrammed by different immune challenges dependent on antigen stimulation levels, metabolic conditions, and the degree of inflammation. T cell-based therapeutic strategies are gaining widespread adoption in oncology and treating inflammatory conditions. Emerging researches reveal that clustered regularly interspaced palindromic repeats-associated protein 9 (CRISPR-Cas9) genome editing has enabled T cells to be more adaptable to specific microenvironments, opening the door to advanced T cell therapies in preclinical and clinical trials. CRISPR-Cas9 can edit both primary T cells and engineered T cells, including CAR-T and TCR-T, in vivo and in vitro to regulate T cell differentiation and activation states. This review first provides a comprehensive summary of the role of CRISPR-Cas9 in T cells and its applications in preclinical and clinical studies for T cell-based therapies. We also explore the application of CRISPR screen high-throughput technology in editing T cells and anticipate the current limitations of CRISPR-Cas9, including off-target effects and delivery challenges, and envisioned improvements in related technologies for disease screening, diagnosis, and treatment.

PARVB promotes malignant melanoma progression and is enhanced by hypoxic conditions

Beta-Parvin (PARVB) is an actin-binding protein with functionality in extracellular matrix binding. Recent studies suggest its potential as a biomarker for various cancers, given its role in governing several malignancies. Yet, its involvement and modulatory mechanisms in malignant melanoma remain under-explored.  In this research, we undertook a comprehensive pan-cancer analysis centered on PARVB. We probed its aberrant expression and prognostic implications, and assessed correlations between PARVB expression and immunocyte infiltration. This expression was subsequently corroborated using clinical samples. Both in vitro and in vivo, we discerned the functional ramifications of PARVB on melanoma. Furthermore, we scrutinized how HIF-1α/2α modulates PARVB and initiated a preliminary investigation into potential downstream pathways influenced by PARVB. Our results illuminate that elevated PARVB expression manifests across various tumors and significantly influences the prognosis of multiple cancers, emphasizing its peculiar expression and prognostic relevance in melanoma. Augmented PARVB levels were inversely proportional to immunocyte penetration in melanoma. Silencing PARVB curtailed cellular proliferation, migration, and invasion in vitro and decelerated tumor expansion in vivo. Notably, hypoxic conditions, triggering HIF-1α/2α activation, appear to elevate PARVB expression by anchoring to the hypoxia-specific responsive element within the PARVB promoter. Enhanced PARVB levels seem intertwined with the activation of cellular proliferation circuits and the damping of inflammatory trajectories. Collectively, these revelations posit PARVB as a potential prognostic indicator and therapeutic linchpin for malignant melanoma.

Tumor immunotherapy resistance: Revealing the mechanism of PD-1 / PD-L1-mediated tumor immune escape

Tumor immunotherapy, an innovative anti-cancer therapy, has showcased encouraging outcomes across diverse tumor types. Among these, the PD-1/PD-L1 signaling pathway is a well-known immunological checkpoint, which is significant in the regulation of immune evasion by tumors. Nevertheless, a considerable number of patients develop resistance to anti-PD-1/PD-L1 immunotherapy, rendering it ineffective in the long run. This research focuses on exploring the factors of PD-1/PD-L1-mediated resistance in tumor immunotherapy. Initially, the PD-1/PD-L1 pathway is characterized by its role in facilitating tumor immune evasion, emphasizing its role in autoimmune homeostasis. Next, the primary mechanisms of resistance to PD-1/PD-L1-based immunotherapy are analyzed, including tumor antigen deletion, T cell dysfunction, increased immunosuppressive cells, and alterations in the expression of PD-L1 within tumor cells. The possible ramifications of altered metabolism, microbiota, and DNA methylation on resistance is also described. Finally, possible resolution strategies for dealing with anti-PD-1/PD-L1 immunotherapy resistance are discussed, placing particular emphasis on personalized therapeutic approaches and the exploration of more potent immunotherapy regimens.

Hydrodynamic Transfection of Hepatocytes for the Study of Hepatocellular Carcinogenesis

Hydrodynamic tail vein injection (HTVi), also called hydrodynamic gene transfer (HGT), is attracting increasing interest for modeling hepatic carcinogenesis. This highly versatile approach reproducibly provides efficient in vivo transfection of hepatocytes with naked DNA. Here, we give an in-depth description of the injection procedure, which is key for the success of the method. HTVi requires the injection of a large volume of a solution containing plasmids into the tail vein of the mouse. The transient right heart overload created by the injection forces the blood to flow back into the hepatic veins, enlarging the endothelial fenestrae and permeabilizing a fraction of hepatocytes for a few seconds. This results in the uptake of plasmids by the permeabilized hepatocytes, giving rise to their in vivo transfection. Including the Sleeping Beauty transposon system among the injected plasmids leads to the stable transfection of a subset of hepatocytes. HTVi is a powerful technique which enables numerous applications in liver cancer biology, such as a study of oncogene cooperation, of tumor heterogeneity, and interaction with the tumor microenvironment.

Emerging Therapeutic Approaches Targeting Ferroptosis in Cancer: Focus on Immunotherapy and Nanotechnology

Ferroptosis is a newly discovered form of programmed cell death characterized by iron overload, ROS accumulation, and lipid peroxidation. It is distinguished by unique morphological, biochemical, and genetic features and stands apart from other known regulated cell death mechanisms. Studies have demonstrated a close association between ferroptosis and various cancers, including liver cancer, lung cancer, renal cell carcinoma, colorectal cancer, pancreatic cancer, and ovarian cancer. Inducing ferroptosis has shown promising results in inhibiting tumor growth and reversing tumor progression. However, the challenge lies in regulating ferroptosis in vivo due to the scarcity of potent compounds that can activate it. Integrating emerging biomedical discoveries and technological innovations with conventional therapies is imperative. Notably, considerable progress has been made in cancer treatment by leveraging immunotherapy and nanotechnology to trigger ferroptosis. This review explores the relationship between ferroptosis and emerging immunotherapies and nanotechnologies, along with their potential underlying mechanisms, offering valuable insights for developing novel cancer treatment strategies.

Low-dose radiotherapy combined with dual PD-L1 and VEGFA blockade elicits antitumor response in hepatocellular carcinoma mediated by activated intratumoral CD8+ exhausted-like T cells

Atezolizumab (anti-PD-L1) combined with bevacizumab (anti-VEGFA) is the first-line immunotherapy for advanced hepatocellular carcinoma (HCC), but the number of patients who benefit from this regimen remains limited. Here, we combine dual PD-L1 and VEGFA blockade (DPVB) with low-dose radiotherapy (LDRT), which rapidly inflames tumors, rendering them vulnerable to immunotherapy. The combinatorial therapy exhibits superior antitumor efficacy mediated by CD8+ T cells in various preclinical HCC models. Treatment efficacy relies upon mobilizing exhausted-like CD8+ T cells (CD8+ Tex) with effector function and cytolytic capacity. Mechanistically, LDRT sensitizes tumors to DPVB by recruiting stem-like CD8+ Tpex, the progenitor exhausted CD8+ T cells, from draining lymph nodes (dLNs) into the tumor via the CXCL10/CXCR3 axis. Together, these results further support the rationale for combining LDRT with atezolizumab and bevacizumab, and its clinical translation.

MYC in liver cancer: mechanisms and targeted therapy opportunities

MYC, a major oncogenic transcription factor, regulates target genes involved in various pathways such as cell proliferation, metabolism and immune evasion, playing a critical role in the tumor initiation and development in multiple types of cancer. In liver cancer, MYC and its signaling pathways undergo significant changes, exerting a profound impact on liver cancer progression, including tumor proliferation, metastasis, dedifferentiation, metabolism, immune microenvironment, and resistance to comprehensive therapies. This makes MYC an appealing target, despite it being previously considered an undruggable protein. In this review, we discuss the role and mechanisms of MYC in liver physiology, chronic liver diseases, hepatocarcinogenesis, and liver cancer progression, providing a theoretical basis for targeting MYC as an ideal therapeutic target for liver cancer. We also summarize and prospect the strategies for targeting MYC, including direct and indirect approaches to abolish the oncogenic function of MYC in liver cancer.

Pan-cancer analysis identified OAS1 as a potential prognostic biomarker for multiple tumor types

Background

2',5'-oligoadenylate synthetase 1 (OAS1), has been reported as a tumor driver gene in breast carcinoma and pancreatic carcinoma. However, the role of OAS1 in most tumors has not been reported.

Methods

The original data of 35 tumor types were down load from the TCGA (The Cancer Genome Atlas) database and Human Protein Atlas (HPA) database. TIMER2, Kmplot, UALCAN, and TISIDB tools were used to investigate the expression and function of OAS1, and the role of OAS1 in prognosis, diagnostic value, and immune characteristics of pan-cancer. LUAD and PRAD cell lines, A549, H1975, PC-3 and C4-2 were utilized to perform cell function tests.

Results

OAS1 expression was up-regulated in 12 tumor types and down-regulated in 2 tumor types. High OAS1 expression was correlated with poor prognosis in 6 tumor types, while high OAS1 expression was correlated with good prognosis in 2 tumor types. OAS1 was correlated with molecular subtypes in 8 tumor types and immune subtypes in 12 tumor types. OAS1 was positively associated with the expression of numerous immune checkpoint genes and tumor mutational burden (TMB). OAS1 had potential diagnostic value in 15 tumor types. Silence of OAS1 significantly inhibited the cell proliferation ability, and promoted G2/M cell cycle arrest of LUAD and PRAD cells. Meanwhile, silence of OAS1 enhanced cisplatin-induced apoptosis of LUAD and PRAD cells, but weakened cell migration.

Conclusion

This pan-cancer study suggests that OAS1can be used as a molecular biomarker for prognosis in pan-cancer and may play an important role in tumor immune response.

Advances in single-cell RNA sequencing and its applications in cancer research

Cancers are a group of heterogeneous diseases characterized by the acquisition of functional capabilities during the transition from a normal to a neoplastic state. Powerful experimental and computational tools can be applied to elucidate the mechanisms of occurrence, progression, metastasis, and drug resistance; however, challenges remain. Bulk RNA sequencing techniques only reflect the average gene expression in a sample, making it difficult to understand tumor heterogeneity and the tumor microenvironment. The emergence and development of single-cell RNA sequencing (scRNA-seq) technologies have provided opportunities to understand subtle changes in tumor biology by identifying distinct cell subpopulations, dissecting the tumor microenvironment, and characterizing cellular genomic mutations. Recently, scRNA-seq technology has been increasingly used in cancer studies to explore tumor heterogeneity and the tumor microenvironment, which has increased the understanding of tumorigenesis and evolution. This review summarizes the basic processes and development of scRNA-seq technologies and their increasing applications in cancer research and clinical practice.

Emerging and potential use of CRISPR in human liver disease

CRISPR is a gene editing tool adapted from naturally occurring defense systems from bacteria. It is a technology that is revolutionizing the interrogation of gene functions in driving liver disease, especially through genetic screens and by facilitating animal knockout and knockin models. It is being used in models of liver disease to identify which genes are critical for liver pathology, especially in genetic liver disease, hepatitis, and in cancer initiation and progression. It holds tremendous promise in treating human diseases directly by editing DNA. It could disable gene function in the case of expression of a maladaptive protein, such as blocking transthyretin as a therapy for amyloidosis, or to correct gene defects, such as restoring the normal functions of liver enzymes fumarylacetoacetate hydrolase or alpha-1 antitrypsin. It is also being studied for treatment of hepatitis B infection. CRISPR is an exciting, evolving technology that is facilitating gene characterization and discovery in liver disease and holds the potential to treat liver diseases safely and permanently.

Ferroptosis: Promising approach for cancer and cancer immunotherapy

Ferroptosis is the cell death induced by ferrous ions and lipid peroxidation accumulation in tumor cells. Targeting ferroptosis, which is regulated by various metabolic and immune elements, might become a novel strategy for anti-tumor therapy. In this review, we will focus on the mechanism of ferroptosis and its interaction with cancer and tumor immune microenvironment, especially for the relationship between immune cells and ferroptosis. Also, we will discuss the latest preclinical progress of the collaboration between the ferroptosis-targeted drugs and immunotherapy, and the best potential conditions for their combined use. It will present a future insight on the possible value of ferroptosis in cancer immunotherapy.

Target immune components to circumvent sorafenib resistance in hepatocellular carcinoma

Sorafenib, a multi-kinase inhibitor, has been approved for cancer treatment for decades, especially hepatocellular carcinoma (HCC). Although sorafenib produced substantial clinical benefits in the initial stage, a large proportion of cancer patients acquired drug resistance in subsequent treatment, which always disturbs clinical physicians. Cumulative evidence unraveled the underlying mechanism of sorafenib, but few reports focused on the role of immune subpopulations, since the immunological rationale of sorafenib resistance has not yet been defined. Here, we reviewed the immunoregulatory effects of sorafenib on the tumor microenvironment and emphasized the potential immunological mechanisms of therapeutic resistance to sorafenib. Moreover, we also summarized the clinical outcomes and ongoing trials in combination of sorafenib with immunotherapy, highlighted the immunotherapeutic strategies to improve sorafenib efficacy, and put forward several prospective questions aimed at guiding future research in overcoming sorafenib resistance in HCC.

Tumor Vasculature as an Emerging Pharmacological Target to Promote Anti-Tumor Immunity

Tumor vasculature abnormality creates a microenvironment that is not suitable for anti-tumor immune response and thereby induces resistance to immunotherapy. Remodeling of dysfunctional tumor blood vessels by anti-angiogenic approaches, known as vascular normalization, reshapes the tumor microenvironment toward an immune-favorable one and improves the effectiveness of immunotherapy. The tumor vasculature serves as a potential pharmacological target with the capacity of promoting an anti-tumor immune response. In this review, the molecular mechanisms involved in tumor vascular microenvironment-modulated immune reactions are summarized. In addition, the evidence of pre-clinical and clinical studies for the combined targeting of pro-angiogenic signaling and immune checkpoint molecules with therapeutic potential are highlighted. The heterogeneity of endothelial cells in tumors that regulate tissue-specific immune responses is also discussed. The crosstalk between tumor endothelial cells and immune cells in individual tissues is postulated to have a unique molecular signature and may be considered as a potential target for the development of new immunotherapeutic approaches.