scholarly journals Tumour Hypoxia-Mediated Immunosuppression: Mechanisms and Therapeutic Approaches to Improve Cancer Immunotherapy

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1006
Author(s):  
Zhe Fu ◽  
Alexandra M. Mowday ◽  
Jeff B. Smaill ◽  
Ian F. Hermans ◽  
Adam V. Patterson

The magnitude of the host immune response can be regulated by either stimulatory or inhibitory immune checkpoint molecules. Receptor-ligand binding between inhibitory molecules is often exploited by tumours to suppress anti-tumour immune responses. Immune checkpoint inhibitors that block these inhibitory interactions can relieve T-cells from negative regulation, and have yielded remarkable activity in the clinic. Despite this success, clinical data reveal that durable responses are limited to a minority of patients and malignancies, indicating the presence of underlying resistance mechanisms. Accumulating evidence suggests that tumour hypoxia, a pervasive feature of many solid cancers, is a critical phenomenon involved in suppressing the anti-tumour immune response generated by checkpoint inhibitors. In this review, we discuss the mechanisms associated with hypoxia-mediate immunosuppression and focus on modulating tumour hypoxia as an approach to improve immunotherapy responsiveness.

2021 ◽  
Vol 15 ◽  
pp. 117955492199628
Author(s):  
Zhaozhen Wu ◽  
Pengfei Cui ◽  
Haitao Tao ◽  
Sujie Zhang ◽  
Junxun Ma ◽  
...  

Poly (ADP-ribose) polymerase (PARP) inhibitors have demonstrated great promise for treating cancers with homologous recombination (HR) defects, such as germline BRCA1/2 mutation. Further studies suggest that PARP inhibitors (PARPi) can also exhibit efficacy in HR-competent cancers, by amplifying the DNA damage and inducing immunogenic cell death, and PARPi lead to increasing tumor neoantigen, upregulation of interferons and PD-L1, and modulation of the tumor microenvironment, which may facilitate a more profound antitumor immune response. Immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 or CTLA-4 have achieved impressive success in the treatment of different malignancies. However, only a subset of populations derive clinical benefit, and the biomarkers and resistance mechanisms are not fully understood. Therefore, given that PARPi could potentiate the therapeutic effect of ICIs, PARPi combined with ICIs are becoming an alternative for patients who cannot benefit from ICI monotherapy. In this review, we focus on the mechanisms and immune role of PARPi and discuss the rationale and clinical studies of this combined regimen.


2019 ◽  
Vol 121 (10) ◽  
pp. 809-818 ◽  
Author(s):  
Ibrahim Halil Sahin ◽  
Mehmet Akce ◽  
Olatunji Alese ◽  
Walid Shaib ◽  
Gregory B. Lesinski ◽  
...  

Abstract Metastatic colorectal cancer (CRC) with a mismatch repair-deficiency (MMR-D)/microsatellite instability-high (MSI-H) phenotype carries unique characteristics such as increased tumour mutational burden and tumour-infiltrating lymphocytes. Studies have shown a sustained clinical response to immune checkpoint inhibitors with dramatic clinical improvement in patients with MSI-H/MMR-D CRC. However, the observed response rates range between 30% and 50% suggesting the existence of intrinsic resistance mechanisms. Moreover, disease progression after an initial positive response to immune checkpoint inhibitor treatment points to acquired resistance mechanisms. In this review article, we discuss the clinical trials that established the efficacy of immune checkpoint inhibitors in patients with MSI-H/MMR-D CRC, consider biomarkers of the immune response and elaborate on potential mechanisms related to intrinsic and acquired resistance. We also provide a perspective on possible future therapeutic approaches that might improve clinical outcomes, particularly in patients with actionable resistance mechanisms.


Author(s):  
Revati Sharma ◽  
Elif Kadife ◽  
Mark Myers ◽  
George Kannourakis ◽  
Prashanth Prithviraj ◽  
...  

AbstractVascular endothelial growth factor tyrosine kinase inhibitors (VEGF-TKIs) have been the mainstay of treatment for patients with advanced renal cell carcinoma (RCC). Despite its early promising results in decreasing or delaying the progression of RCC in patients, VEGF-TKIs have provided modest benefits in terms of disease-free progression, as 70% of the patients who initially respond to the treatment later develop drug resistance, with 30% of the patients innately resistant to VEGF-TKIs. In the past decade, several molecular and genetic mechanisms of VEGF-TKI resistance have been reported. One of the mechanisms of VEGF-TKIs is inhibition of the classical angiogenesis pathway. However, recent studies have shown the restoration of an alternative angiogenesis pathway in modulating resistance. Further, in the last 5 years, immune checkpoint inhibitors (ICIs) have revolutionized RCC treatment. Although some patients exhibit potent responses, a non-negligible number of patients are innately resistant or develop resistance within a few months to ICI therapy. Hence, an understanding of the mechanisms of VEGF-TKI and ICI resistance will help in formulating useful knowledge about developing effective treatment strategies for patients with advanced RCC. In this article, we review recent findings on the emerging understanding of RCC pathology, VEGF-TKI and ICI resistance mechanisms, and potential avenues to overcome these resistance mechanisms through rationally designed combination therapies.


Thorax ◽  
2021 ◽  
pp. thoraxjnl-2021-217260
Author(s):  
Tommaso Morelli ◽  
Kohei Fujita ◽  
Gil Redelman-Sidi ◽  
Paul T Elkington

Immune checkpoint inhibitors (ICIs) have revolutionised cancer treatment. However, immune-related adverse events (irAEs) are a common side effect which can mimic infection. Additionally, treatment of irAEs with corticosteroids and other immunosuppressant agents can lead to opportunistic infection, which we have classed as immunotherapy infections due to immunosuppression. However, emerging reports demonstrate that some infections can be precipitated by ICIs in the absence of immunosuppressive treatment, in contrast to the majority of reported cases. These infections are characterised by a dysregulated inflammatory immune response, and so we propose they are described as immunotherapy infections due to dysregulated immunity. This review summarises the rapidly emerging evidence of these phenomena and proposes a new framework for considering infection in the context of cancer immunotherapy.


Diagnostics ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 146 ◽  
Author(s):  
Fulvio Borella ◽  
Eleonora Ghisoni ◽  
Gaia Giannone ◽  
Stefano Cosma ◽  
Chiara Benedetto ◽  
...  

Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological cancers. Despite improvements in medical treatments, the prognosis for EOC remains poor, and there is an urgent need for new therapeutic strategies. Immune checkpoint inhibitors (CPIs) have dramatically improved survival of several cancers and are under evaluation in OC. Unfortunately, CPIs have shown globally unsatisfactory results. The aim of this manuscript is to critically review the results from early-phase trials with CPIs in terms of safety and activity, discuss the possible reasons for disappointing results and the new therapeutic approaches to improve patient outcomes.


2020 ◽  
Vol 21 (17) ◽  
pp. 6176 ◽  
Author(s):  
Yolla Haibe ◽  
Ziad El Husseini ◽  
Rola El Sayed ◽  
Ali Shamseddine

The treatment landscape in oncology has witnessed a major revolution with the introduction of checkpoint inhibitors: anti-PD1, anti-PDL1 and anti-CTLA-4. These agents enhance the immune response towards cancer cells instead of targeting the tumor itself, contrary to standard chemotherapy. Although long-lasting durable responses have been observed with immune checkpoints inhibitors, the response rate remains relatively low in many cases. Some patients respond in the beginning but then eventually develop acquired resistance to treatment and progress. Other patients having primary resistance never respond. Multiple studies have been conducted to further elucidate these variations in response in different tumor types and different individuals. This paper provides an overview of the mechanisms of resistance to immune checkpoint inhibitors and highlights the possible therapeutic approaches under investigation aiming to overcome such resistance in order to improve the clinical outcomes of cancer patients.


Immunotherapy ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 513-529
Author(s):  
Dmitrii Shek ◽  
Scott A Read ◽  
Liia Akhuba ◽  
Liang Qiao ◽  
Bo Gao ◽  
...  

Non-coding RNAs (ncRNAs) are an abundant component of the human transcriptome. Their biological role, however, remains incompletely understood. Nevertheless, ncRNAs are highly associated with cancer development and progression due to their ability to modulate gene expression, protein translation and growth pathways. Immune-checkpoint inhibitors (ICIs) are considered one of the most promising and highly effective therapeutic approaches for cancer treatment. ICIs are monoclonal antibodies targeting immune checkpoints such as CTLA-4, PD-1 and PD-L1 signalling pathways that stimulate T cell cytotoxicity and can result in tumor growth suppression. This Review will summarize existing knowledge regarding ncRNAs and their role in cancer and ICI therapy. In addition, we will discuss potential mechanisms by which ncRNAs may influence ICI treatment outcomes.


2020 ◽  
Vol 19 (4) ◽  
pp. 123-131
Author(s):  
G. A. Janus ◽  
A. G. Ievleva ◽  
E. N. Suspitsyn ◽  
V. I. Tyurin ◽  
I. V. Bizin ◽  
...  

Despite the unprecedented success in using immune checkpoint inhibitors in the treatment of lung cancer, melanoma, hypermutable tumors of various localization, etc., a significant proportion of patients receiving these drugs do not respond to treatment. Predictive markers routinely used in the selection of patients for immunotherapy, in particular, the level of expression of PD -L1 and the presence of microsatellite instability, have certain limitations. Over the past decade, many other biomarkers designed to predict response to immunotherapy have been proposed, namely: tymor mutation burden, composition of lymphocytic infiltrate; allelic composition of the major histocompatibility complex; relationship between the numbers of different formed elements of blood as well as between its biochemical parameters; microflora of the digestive tract, etc. These markers can directly or indirectly reflect the immunogenicity of the tumor itself, as well as the state of systemic and intratumoral immune response. The predictive power and reliability of these markers are extremely different. When preparing this review, we conducted a literature search for recent studies regarding predictors of efficacy for immune checkpoint inhibitors published in the journals included in the databases, such as Pubmed, Web of Science, and Scopus.


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