Inhibition of the PI3K/mTOR Pathway in Breast Cancer to Enhance Response to Immune Checkpoint Inhibitors in Breast Cancer

Targeting cytotoxic lymphocyte antigen 4 (CTLA-4) in breast cancer

Breast cancer (BC) has a high mortality rate and is one of the most common malignancies in the world. Initially, BC was considered non-immunogenic, but a paradigm shift occurred with the discovery of tumor-infiltrating lymphocytes (TILs) and regulatory T cells (Tregs) in the BC tumor microenvironment. CTLA-4 (Cytotoxic T-lymphocyte-associated protein 4) immunotherapy has emerged as a treatment option for BC, but it has limitations, including suboptimal antitumor effects and toxicity. Research has demonstrated that anti-CTLA-4 combination therapies, such as Treg depletion, cancer vaccines, and modulation of the gut microbiome, are significantly more effective than CTLA-4 monoclonal antibody (mAB) monotherapy. Second-generation CTLA-4 antibodies are currently being developed to mitigate immune-related adverse events (irAEs) and augment antitumor efficacy. This review examines anti-CTLA-4 mAB in BC, both as monotherapy and in combination with other treatments, and sheds light on ongoing clinical trials, novel CTLA-4 therapeutic strategies, and potential utility of biomarkers in BC.

Beyond Anti-PD-1/PD-L1: Improving Immune Checkpoint Inhibitor Responses in Triple-Negative Breast Cancer

The introduction of anti-programmed cell death protein-1 (anti-PD-1) to the clinical management of triple-negative breast cancer (TNBC) represents a breakthrough for a disease whose treatment has long relied on the standards of chemotherapy and surgery. Nevertheless, few TNBC patients achieve a durable remission in response to anti-PD-1, and there is a need to develop strategies to maximize the potential benefit of immune checkpoint inhibition (ICI) for TNBC patients. In the present review, we discuss three conceptual strategies to improve ICI response rates in TNBC patients. The first effort involves improving patient selection. We discuss proposed biomarkers of response and resistance to anti-PD-1, concluding that an optimal biomarker will likely be multifaceted. The second effort involves identifying existing targeted therapies or chemotherapies that may synergize with ICI. In particular, we describe recent efforts to use inhibitors of the PI3K/AKT or RAS/MAPK/ERK pathways in combination with ICI. Third, considering the possibility that targeting the PD-1 axis is not the most promising strategy for TNBC treatment, we describe ongoing efforts to identify novel immunotherapy strategies.

Gedatolisib shows superior potency and efficacy versus single-node PI3K/AKT/mTOR inhibitors in breast cancer models

The PI3K, AKT, and mTOR (PAM) pathway is frequently dysregulated in breast cancer (BC) to accommodate high catabolic and anabolic activities driving tumor growth. Current therapeutic options for patients with hormone receptor (HR) + / HER2- advanced BC (ABC) include PAM inhibitors that selectively inhibit only one PAM pathway node, which can lead to drug resistance as cells rapidly adapt to maintain viability. We hypothesized that gedatolisib, which potently inhibits all Class I PI3K isoforms, as well as mTORC1 and mTORC2, may be more effective in BC cells than single-node PAM inhibitors by limiting adaptive resistances. By using multiple functional assays, a panel of BC cell lines was evaluated for their sensitivity to four different PAM inhibitors: gedatolisib (pan-PI3K/mTOR inhibitor), alpelisib (PI3Kα inhibitor), capivasertib (AKT inhibitor), and everolimus (mTORC1 inhibitor). Gedatolisib exhibited more potent and efficacious anti-proliferative and cytotoxic effects regardless of the PAM pathway mutational status of the cell lines compared to the single-node PAM inhibitors. The higher efficacy of gedatolisib was confirmed in three-dimensional culture and in BC PDX models. Mechanistically, gedatolisib decreased cell survival, DNA replication, cell migration and invasion, protein synthesis, glucose consumption, lactate production, and oxygen consumption more effectively than the other PAM inhibitors tested. These results indicate that inhibition of multiple PAM pathway nodes by a pan-PI3K/mTOR inhibitor like gedatolisib may be more effective at inducing anti-tumor activity than single-node PAM inhibitors. A global Phase 3 study is currently evaluating gedatolisib plus fulvestrant with and without palbociclib in patients with HR+/HER2- ABC.

Endogenous pAKT activity is associated with response to AKT inhibition alone and in combination with immune checkpoint inhibition in murine models of TNBC

Triple-negative breast cancer (TNBC) is a heterogeneous and challenging-to-treat breast cancer subtype. The clinical introduction of immune checkpoint inhibitors (ICI) for TNBC has had mixed results, and very few patients achieved a durable response. The PI3K/AKT pathway is frequently mutated in breast cancer. Given the important roles of the PI3K pathway in immune and tumor cell signaling, there is an interest in using inhibitors of this pathway to increase the response to ICI. This study sought to determine if AKT inhibition could enhance the response to ICI in murine TNBC models. We further sought to understand underlying mechanisms of response or non-response to AKT inhibition in combination with ICI. Using four murine TNBC-like cell lines and corresponding orthotopic mouse tumor models, we found that hyperactivity of the PI3K pathway, as evidenced by levels of phospho-AKT rather than PI3K pathway mutational status, was associated with response to AKT inhibition alone and in combination with ICI. Additional mutations in other growth regulatory pathways could override the response of PI3K pathway mutant tumors to AKT inhibition. Furthermore, we observed that AKT inhibition enhanced the response to ICI in an already sensitive model. However, AKT inhibition failed to convert ICI-resistant tumors, to responsive tumors. These findings suggest that analysis of both the mutational status and phospho-AKT protein levels may be beneficial in predicting which TNBC tumors will respond to AKT inhibition in combination with ICI.

Harnessing the potential of CD40 agonism in cancer therapy

CD40 is a member of the tumor necrosis factor (TNF) receptor superfamily of receptors expressed on a variety of cell types. The CD40-CD40L interaction gives rise to many immune events, including the licensing of dendritic cells to activate CD8+ effector T cells, as well as the facilitation of B cell activation, proliferation, and differentiation. In malignant cells, the expression of CD40 varies among cancer types, mediating cellular proliferation, apoptosis, survival and the secretion of cytokines and chemokines. Agonistic human anti-CD40 antibodies are emerging as an option for cancer treatment, and early-phase clinical trials explored its monotherapy or combination with radiotherapy, chemotherapy, immune checkpoint blockade, and other immunomodulatory approaches. In this review, we present the current understanding of the mechanism of action for CD40, along with results from the clinical development of agonistic human CD40 antibodies in cancer treatment (selicrelumab, CDX-1140, APX005M, mitazalimab, 2141-V11, SEA-CD40, LVGN7409, and bispecific antibodies). This review also examines the safety profile of CD40 agonists in both preclinical and clinical settings, highlighting optimized dosage levels, potential adverse effects, and strategies to mitigate them.

Cognitive functions of patients treated with chemotherapy: A comparative study

OBJECTIVES

Chemobrain is a well-established clinical syndrome that has become an increasing concern because of the growing number of long-term cancer survivors. It refers to the post-chemotherapy related cognitive dysfunction. The aim of this study was to objectively assess the impact of cancer treatment on the cognition of cancer patients.

METHODS

This was a convenience sample comparative study conducted at the Hematology and Oncology Department of Hôtel Dieu de France University Hospital in Beirut, Lebanon. It included cancer patients (G1) aged under 65 years who had already been treated for cancer compared to two control groups. The first control group (G2) consisted of treatment-naïve cancer patients aged under 65, and the second group (G3) was recruited from a pool of healthy controls aged between 40 and 65 years. All participants were asked to complete the part B of the trail making test (TMT) and the digital symbolic substitution test (DSST).

RESULTS

In the bivariate analysis, patients in G1 had significantly higher scores than patients in G2 (P=0.017) and G3 (P<0.001) on the TMT-B. However, patients in G1 only had lower scores on DSST when compared with G3 (P=0.017). In the logistic regression taking different groups two-by-two as the dependent variable, the only significant difference was found in the comparison between G2 and G3 with higher TMT-B scores more in favor of belonging to G2 (OR=0.946; P=0.003).

CONCLUSIONS

Our results suggest that, after controlling for anxiety and depression symptoms, patients treated with chemotherapy have significantly poorer outcomes on the DSST and TMT-B than treatment-naïve cancer patients and healthy controls. However, when taking confounding factors into account, the difference only persisted between patients undergoing chemotherapy and healthy controls. These findings are in favor of a multifactor cognitive impairment in patients with cancer partially related to chemotherapeutic treatment.

Oncogenic PIK3CA recruits myeloid-derived suppressor cells to shape the immunosuppressive tumour microenvironment in luminal breast cancer through the 5-lipoxygenase-dependent arachidonic acid pathway

BACKGROUND

Oncogenic PIK3CA mutations (PIK3CAmut ) frequently occur in a higher proportion in luminal breast cancer (LBC), especially in refractory advanced cases, and are associated with changes in tumour cellular metabolism. Nevertheless, its effect on the progression of the immune microenvironment (TIME) within tumours and vital molecular events remains veiled.

METHODS

Multiplex immunohistochemistry (mIHC) and single-cell mass cytometry (CyTOF) was used to describe the landscape of TIME in PIK3CAmut LBC. The PIK3CA mutant cell lines were established using CRISPER/Cas9 system. The gene expression levels, protein secretion and activity of signaling pathways were measured by real-time RT-PCR, ELISA, immunofluorescence staining or western blotting. GSEA analysis, transwell chemotaxis assay, live cell imaging, flow cytometry metabolite analysis targeting arachidonic acid, Dual-luciferase reporter assay, and Chromatin immunoprecipitation assay were used to investigate the underlying function and mechanism of the PI3K/5-LOX/LTB4 axis.

RESULTS

PIK3CAmut LBC cells can induce an immunosuppressive TIME by recruiting myeloid-derived suppressor cells (MDSCs) and excluding cytotoxic T cells via the arachidonic acid (AA) metabolism pathway. Mechanistically, PIK3CAmut activates the transcription of 5-lipoxygenase (5-LOX) in a STAT3-dependent manner, which in turn directly results in high LTB4 production, binding to BLT2 on MDSCs and promoting their infiltration. Since a suppressive TIME is a critical barrier for the success of cancer immunotherapy, the strategies that can convert "cold" tumours into "hot" tumours were compared. Targeted therapy against the PI3K/5-LOX/LTB4 axis synergizing with immune checkpoint blockade (ICB) therapy achieved dramatic shrinkage in vivo.

CONCLUSIONS

The results emphasize that PIK3CAmut can induce immune evasion by recruiting MDSCs through the 5-LOX-dependent AA pathway, and combination targeted therapy with ICB may provide a promising treatment option for refractory advanced LBC patients.

Recent research and clinical progress of CTLA-4-based immunotherapy for breast cancer

Breast cancer is characterized by a high incidence rate and its treatment challenges, particularly in certain subtypes. Consequently, there is an urgent need for the development of novel therapeutic approaches. Immunotherapy utilizing immune checkpoint inhibitors (ICIs) is currently gaining momentum for the treatment of breast cancer. Substantial progress has been made in clinical studies employing cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitors for breast cancer, but the cure rates are relatively low. To improve the efficacy of CTLA-4-based therapy for breast cancer, further research is imperative to explore more effective immune-based treatment strategies. In addition to monotherapy, CTLA-4 inhibitors are also being investigated in combination with other ICIs or alternative medications. However, it should be noted that immune-based treatments may cause adverse events. This review focuses on the mechanisms of CTLA-4 inhibitor monotherapy or combination therapy in breast cancer. We systematically summarize the latest research and clinical advances in CTLA-4-based immunotherapy for breast cancer, providing new perspectives on the treatment of breast cancer. In addition, this review highlights the immune-related adverse events (irAEs) associated with CTLA-4 inhibitors, providing insights into the development of appropriate clinical tumor immunotherapy regimens and intervention strategies.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Pilot clinical trial and phenotypic analysis in chemotherapy-pretreated, metastatic triple-negative breast cancer patients treated with oral TAK-228 and TAK-117 (PIKTOR) to increase DNA damage repair deficiency followed by cisplatin and nab paclitaxel

BACKGROUND

A subset of triple-negative breast cancers (TNBCs) have homologous recombination deficiency with upregulation of compensatory DNA repair pathways. PIKTOR, a combination of TAK-228 (TORC1/2 inhibitor) and TAK-117 (PI3Kα inhibitor), is hypothesized to increase genomic instability and increase DNA damage repair (DDR) deficiency, leading to increased sensitivity to DNA-damaging chemotherapy and to immune checkpoint blockade inhibitors.

METHODS

10 metastatic TNBC patients received 4 mg TAK-228 and 200 mg TAK-117 (PIKTOR) orally each day for 3 days followed by 4 days off, weekly, until disease progression (PD), followed by intravenous cisplatin 75 mg/m2 plus nab paclitaxel 220 mg/m2 every 3 weeks for up to 6 cycles. Patients received subsequent treatment with pembrolizumab and/or chemotherapy. Primary endpoints were objective response rate with cisplatin/nab paclitaxel and safety. Biopsies of a metastatic lesion were collected prior to and at PD on PIKTOR. Whole exome and RNA-sequencing and reverse phase protein arrays (RPPA) were used to phenotype tumors pre- and post-PIKTOR for alterations in DDR, proliferation, and immune response.

RESULTS

With cisplatin/nab paclitaxel (cis/nab pac) therapy post PIKTOR, 3 patients had clinical benefit (1 partial response (PR) and 2 stable disease (SD) ≥ 6 months) and continued to have durable benefit in progression-free survival with pembrolizumab post-cis/nab pac for 1.2, 2, and 3.6 years. Their post-PIKTOR metastatic tissue displayed decreased mismatch repair (MMR), increased tumor mutation burden, and significantly lower levels of 53BP1, DAG Lipase β, GCN2, AKT Ser473, and PKCzeta Thr410/403 compared to pre-PIKTOR tumor tissue.

CONCLUSIONS

Priming patients' chemotherapy-pretreated metastatic TNBC with PIKTOR led to very prolonged response/disease control with subsequent cis/nab pac, followed by pembrolizumab, in 3 of 10 treated patients. Our multi-omics approach revealed a higher number of genomic alterations, reductions in MMR, and alterations in immune and stress response pathways post-PIKTOR in patients who had durable responses.

TRIAL REGISTRATION

This clinical trial was registered on June 21, 2017, at ClinicalTrials.gov using identifier NCT03193853.

Lipid metabolism reprogramming of CD8+ T cell and therapeutic implications in cancer

Effector, memory and exhaustion are three phenotypes of CD8⁺ T cell. In tumor microenvironment (TME), metabolism dysfunction of the three should take the blame for immune escape. Against background of CD8⁺ T cell in normal development, multiple determinants in TME, including nutrition competition, PD-1 signals and other cancer- CD8⁺ T cell interaction, cause metabolism reprograming, including failure in energy metabolism and other abnormal lipid metabolism. Further, incompatibility of different CD8⁺ T cell metabolism pattern results in unresponsiveness of immune checkpoint blockade (ICB). Therefore, combination of ICB and drugs aiming at abnormal lipid metabolism provides promising direction to improve cancer therapy.

Metabolic Interventions in Tumor Immunity: Focus on Dual Pathway Inhibitors

The metabolism of tumors and immune cells in the tumor microenvironment (TME) can affect the fate of cancer and immune responses. Metabolic reprogramming can occur following the activation of metabolic-related signaling pathways, such as phosphoinositide 3-kinases (PI3Ks) and the mammalian target of rapamycin (mTOR). Moreover, various tumor-derived immunosuppressive metabolites following metabolic reprogramming also affect antitumor immune responses. Evidence shows that intervention in the metabolic pathways of tumors or immune cells can be an attractive and novel treatment option for cancer. For instance, administrating inhibitors of various signaling pathways, such as phosphoinositide 3-kinases (PI3Ks), can improve T cell-mediated antitumor immune responses. However, dual pathway inhibitors can significantly suppress tumor growth more than they inhibit each pathway separately. This review discusses the latest metabolic interventions by dual pathway inhibitors as well as the advantages and disadvantages of this therapeutic approach.

Effect of metabolism on the immune microenvironment of breast cancer

Breast cancer (BC) is a highly prevalent primary malignancy worldwide with poor prognosis. Despite the development of aggressive interventions, mortality due to BC remains high. BC cells reprogram nutrient metabolism to adapt to the energy acquisition and progression of the tumor. The metabolic changes in cancer cells are closely related to the abnormal function and effect of immune cells and immune factors, including chemokines, cytokines, and other related effector molecules in the tumor microenvironment (TME), leading to tumor immune escape, whereby the complex crosstalk between immune cells and cancer cells has been considered the key mechanism regulating cancer progression. In this review, we summarized the latest findings on metabolism-related processes in the immune microenvironment during BC progression. Our findings showing the impact of metabolism on the immune microenvironment may suggest new strategies for regulating the immune microenvironment and attenuating BC through metabolic interventions.

Immunotherapies against HER2-Positive Breast Cancer

Breast cancer is the leading cause of cancer-related deaths among women worldwide. HER2-positive breast cancer, which represents 15-20% of all cases, is characterized by the overexpression of the HER2 receptor. Despite the variety of treatments available for HER2-positive breast cancer, both targeted and untargeted, many patients do not respond to therapy and relapse and eventually metastasize, with a poor prognosis. Immunotherapeutic approaches aim to enhance the antitumor immune response to prevent tumor relapse and metastasis. Several immunotherapies have been approved for solid tumors, but their utility for HER2-positive breast cancer has yet to be confirmed. In this review, we examine the different immunotherapeutic strategies being tested in HER2-positive breast cancer, from long-studied cancer vaccines to immune checkpoint blockade, which targets immune checkpoints in both T cells and tumor cells, as well as the promising adoptive cell therapy in various forms. We discuss how some of these new approaches may contribute to the prevention of tumor progression and be used after standard-of-care therapies for resistant HER2-positive breast tumors, highlighting the benefits and drawbacks of each. We conclude that immunotherapy holds great promise for the treatment of HER2-positive tumors, with the potential to completely eradicate tumor cells and prevent the progression of the disease.

PI3K-AKT-Targeting Breast Cancer Treatments: Natural Products and Synthetic Compounds

Breast cancer is the most commonly diagnosed cancer in women. The high incidence of breast cancer, which is continuing to rise, makes treatment a significant challenge. The PI3K-AKT pathway and its downstream targets influence various cellular processes. In recent years, mounting evidence has shown that natural products and synthetic drugs targeting PI3K-AKT signaling have the potential to treat breast cancer. In this review, we discuss the role of the PI3K-AKT signaling pathway in the occurrence and development of breast cancer and highlight PI3K-AKT-targeting natural products and drugs in clinical trials for the treatment of breast cancer.

A Phase 1B open-label study of gedatolisib (PF-05212384) in combination with other anti-tumour agents for patients with advanced solid tumours and triple-negative breast cancer

BACKGROUND

This Phase 1b study (B2151002) evaluated the PI3K/mTOR inhibitor gedatolisib (PF-05212384) in combination with other anti-tumour agents in advanced solid tumours.

METHODS

Patients with various malignancies were administered gedatolisib (90‒310 mg intravenously every week [QW]) plus docetaxel (arm A) or cisplatin (arm B) (each 75 mg/m2 intravenously Q3W) or dacomitinib (30 or 45 mg/day orally). The safety and tolerability of combination therapies were assessed during dose escalation; objective response (OR) and safety were assessed during dose expansion.

RESULTS

Of 110 patients enrolled, 107 received gedatolisib combination treatment. Seven of 70 (10.0%) evaluable patients had dose-limiting toxicities; the most common was grade 3 oral mucositis (n = 3). Based upon reprioritisation of the sponsor's portfolio, dose expansion focused on arm B, gedatolisib (180 mg QW) plus cisplatin in patients (N = 22) with triple-negative breast cancer (TNBC). OR (95% CI) was achieved in four of ten patients in first-line (overall response rate 40.0% [12.2-73.8%]) and four of 12 in second/third-line (33.3% [9.9-65.1%]) settings. One patient in each TNBC arm (10%, first-line; 8.3%, second/third-line) achieved a complete response.

CONCLUSIONS

Gedatolisib combination therapy showed an acceptable tolerability profile, with clinical activity at the recommended Phase 2 dose in patients with TNBC.

CLINICAL TRIAL

ClinicalTrial.gov: NCT01920061.

Recent Advances and Challenges in Cancer Immunotherapy

Simple Summary

Immunotherapy helps a person’s immune system to target tumor cells. Recent advances in cancer immunotherapy, including immune checkpoint inhibition, chimeric antigen receptor T-cell therapy and cancer vaccination, have changed the landscape of cancer treatment. These approaches have had profound success in certain cancer types but still fail in the majority of cases. This review will cover both successes and current challenges in cancer immunotherapy, as well as recent advances in the field of basic tumor immunology that will allow us to overcome resistance to existing treatments.

Abstract

Cancer immunotherapy has revolutionized the field of oncology in recent years. Harnessing the immune system to treat cancer has led to a large growth in the number of novel immunotherapeutic strategies, including immune checkpoint inhibition, chimeric antigen receptor T-cell therapy and cancer vaccination. In this review, we will discuss the current landscape of immuno-oncology research, with a focus on elements that influence immunotherapeutic outcomes. We will also highlight recent advances in basic aspects of tumor immunology, in particular, the role of the immunosuppressive cells within the tumor microenvironment in regulating antitumor immunity. Lastly, we will discuss how the understanding of basic tumor immunology can lead to the development of new immunotherapeutic strategies.

PI3K/AKT/mTOR-Targeted Therapy for Breast Cancer

Phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT) and mechanistic target of rapamycin (mTOR) (PAM) pathways play important roles in breast tumorigenesis and confer worse prognosis in breast cancer patients. The inhibitors targeting three key nodes of these pathways, PI3K, AKT and mTOR, are continuously developed. For breast cancer patients to truly benefit from PAM pathway inhibitors, it is necessary to clarify the frequency and mechanism of abnormal alterations in the PAM pathway in different breast cancer subtypes, and further explore reliable biomarkers to identify the appropriate population for precision therapy. Some PI3K and mTOR inhibitors have been approved by regulatory authorities for the treatment of specific breast cancer patient populations, and many new-generation PI3K/mTOR inhibitors and AKT isoform inhibitors have also been shown to have good prospects for cancer therapy. This review summarizes the changes in the PAM signaling pathway in different subtypes of breast cancer, and the latest research progress about the biomarkers and clinical application of PAM-targeted inhibitors.

Immunomodulatory Properties of PI3K/AKT/mTOR and MAPK/MEK/ERK Inhibition Augment Response to Immune Checkpoint Blockade in Melanoma and Triple-Negative Breast Cancer

Hyperactivation of PI3K/AKT/mTOR and MAPK/MEK/ERK signaling pathways is commonly observed in many cancers, including triple-negative breast cancer (TNBC) and melanoma. Moreover, the compensatory upregulation of the MAPK/MEK/ERK pathway has been associated with therapeutic resistance to targeted inhibition of the PI3K/AKT/mTOR pathway, and vice versa. The immune-modulatory effects of both PI3K and MAPK inhibition suggest that inhibition of these pathways might enhance response to immune checkpoint inhibitors (ICIs). ICIs have become the standard-of-care for metastatic melanoma and are recently an option for TNBC when combined with chemotherapy, but alternative options are needed when resistance develops. In this review, we present the current mechanistic understandings, along with preclinical and clinical evidence, that outline the efficacy and safety profile of combinatorial or sequential treatments with PI3K inhibitors, MAPK inhibitors, and ICIs for treatment of malignant melanoma and metastatic TNBC. This approach may present a potential strategy to overcome resistance in patients who are a candidate for ICI therapy with tumors harboring either or both of these pathway-associated mutations.

Targeting oncogene and non-oncogene addiction to inflame the tumour microenvironment

Immune checkpoint inhibitors (ICIs) have revolutionized the clinical management of multiple tumours. However, only a few patients respond to ICIs, which has generated considerable interest in the identification of resistance mechanisms. One such mechanism reflects the ability of various oncogenic pathways, as well as stress response pathways required for the survival of transformed cells (a situation commonly referred to as 'non-oncogene addiction'), to support tumour progression not only by providing malignant cells with survival and/or proliferation advantages, but also by establishing immunologically 'cold' tumour microenvironments (TMEs). Thus, both oncogene and non-oncogene addiction stand out as promising targets to robustly inflame the TME and potentially enable superior responses to ICIs.

Barriers to Immunotherapy in Ovarian Cancer: Metabolic, Genomic, and Immune Perturbations in the Tumour Microenvironment

A lack of explicit early clinical signs and effective screening measures mean that ovarian cancer (OC) often presents as advanced, incurable disease. While conventional treatment combines maximal cytoreductive surgery and platinum-based chemotherapy, patients frequently develop chemoresistance and disease recurrence. The clinical application of immune checkpoint blockade (ICB) aims to restore anti-cancer T-cell function in the tumour microenvironment (TME). Disappointingly, even though tumour infiltrating lymphocytes are associated with superior survival in OC, ICB has offered limited therapeutic benefits. Herein, we discuss specific TME features that prevent ICB from reaching its full potential, focussing in particular on the challenges created by immune, genomic and metabolic alterations. We explore both recent and current therapeutic strategies aiming to overcome these hurdles, including the synergistic effect of combination treatments with immune-based strategies and review the status quo of current clinical trials aiming to maximise the success of immunotherapy in OC.