Combinatorial Approach to Improve Cancer Immunotherapy: Rational Drug Design Strategy to Simultaneously Hit Multiple Targets to Kill Tumor Cells and to Activate the Immune System

Further knowledge and developments in resistance mechanisms to immune checkpoint inhibitors

The past decade has witnessed a revolution in cancer treatment, shifting from conventional drugs (chemotherapies) towards targeted molecular therapies and immune-based therapies, in particular immune-checkpoint inhibitors (ICIs). These immunotherapies release the host's immune system against the tumor and have shown unprecedented durable remission for patients with cancers that were thought incurable, such as metastatic melanoma, metastatic renal cell carcinoma (RCC), microsatellite instability (MSI) high colorectal cancer and late stages of non-small cell lung cancer (NSCLC). However, about 80% of the patients fail to respond to these immunotherapies and are therefore left with other less effective and potentially toxic treatments. Identifying and understanding the mechanisms that enable cancerous cells to adapt to and eventually overcome therapy can help circumvent resistance and improve treatment. In this review, we describe the recent discoveries on the onco-immunological processes which govern the tumor microenvironment and their impact on the resistance to PD-1/PD-L1 checkpoint blockade.

A pan-cancer analysis of the oncogenic and immunological roles of transglutaminase 1 (TGM1) in human cancer

BACKGROUND

There is currently a limited number of studies on transglutaminase type 1 (TGM1) in tumors. The objective of this study is to perform a comprehensive analysis across various types of cancer to determine the prognostic significance of TGM1 in tumors and investigate its role in the immune environment.

METHOD

Pan-cancer and mutational data were retrieved from the TCGA database and analyzed using R (version 3.6.4) and its associated software package. The expression difference and prognosis of TGM1 were examined, along with its correlation with tumor heterogeneity, stemness, mutation landscape, and RNA modification. Additionally, the relationship between TGM1 expression and tumor immunity was investigated using the TIMER method.

RESULTS

TGM1 is expressed differently in various tumors and normal samples and is associated with the overall survival and progression-free time of KIRC, ACC, SKCM, LIHC, and STES. In LICH, we found a negative correlation between TGM1 expression and 6 indicators of tumor stemness. The mutation frequencies of BLCA, LIHC, and KIRC were 1.7%, 0.3%, and 0.3% respectively. In BLCA and BRCA, there was a significant correlation between TGM1 expression and the infiltration of CD4 + T cells, CD8 + T cells, neutrophils, and dendritic cells.

CONCLUSION

TGM1 has the potential to serve as both a prognostic marker and a drug target.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

Engineered IL-7 synergizes with IL-12 immunotherapy to prevent T cell exhaustion and promote memory without exacerbating toxicity

Cancer immunotherapy is moving toward combination regimens with agents of complementary mechanisms of action to achieve more frequent and robust efficacy. However, compared with single-agent therapies, combination immunotherapies are associated with increased overall toxicity because the very same mechanisms also work in concert to enhance systemic inflammation and promote off-tumor toxicity. Therefore, rational design of combination regimens that achieve improved antitumor control without exacerbated toxicity is a main objective in combination immunotherapy. Here, we show that the combination of engineered, tumor matrix-binding interleukin-7 (IL-7) and IL-12 achieves remarkable anticancer effects by activating complementary pathways without inducing any additive immunotoxicity. Mechanistically, engineered IL-12 provided effector properties to T cells, while IL-7 prevented their exhaustion and boosted memory formation as assessed by tumor rechallenge experiments. The dual combination also rendered checkpoint inhibitor (CPI)-resistant genetically engineered melanoma model responsive to CPI. Thus, our approach provides a framework of evaluation of rationally designed combinations in immuno-oncology and yields a promising therapy.

The Role of Regulatory T Cells in Cancer Treatment Resistance

Despite tremendous progress in cancer treatment in recent years, treatment resistance is still a major challenge for a great number of patients. One of the main causes is regulatory T lymphocytes (Tregs), which suppress excessive inflammatory responses via the secretion of immunosuppressive cytokines and upregulate the immune checkpoints. Their abundance causes an immunosuppressive reprogramming of the tumor environment, which is ideal for tumor growth and drug inefficiency. Hence, regiments that can regain tumor immunogenicity are a promising strategy to overcome Tregs-mediated drug resistance. However, to develop effective therapeutic regimens, it is essential to understand the molecular mechanisms of Treg-mediated resistance. In this article, we gathered a comprehensive summary of the current knowledge on molecular mechanisms and the role of Tregs in cancer treatment resistance, including cancer immunotherapy, targeted therapy, chemotherapy, and radiotherapy.

Efficacy evaluation of chimeric antigen receptor-modified human peritoneal macrophages in the treatment of gastric cancer

BACKGROUND

Gastric cancer is one of the most common cancers. Peritoneal carcinomatosis (PC) appears to be the most common pattern of recurrence, and more than half of the GC patients eventually die from PC. Novel strategies for the management of patients with PC are urgently needed. Recently, rapid progress has been made in adoptive transfer therapy by using macrophages as the effector cells due to their capabilities of phagocytosis, antigen presentation, and high penetration. Here, we generated a novel macrophage-based therapy and investigated anti-tumoral effects on GC and potential toxicity.

METHODS

We developed a novel Chimeric Antigen Receptor-Macrophage (CAR-M) based on genetically modifying human peritoneal macrophages (PMs), expressing a HER2-FcεR1γ-CAR (HF-CAR). We tested HF-CAR macrophages in a variety of GC models in vitro and in vivo.

RESULTS

HF-CAR-PMs specifically targeted HER2-expressed GC, and harboured the FcεR1γ moieties to trigger engulfment. Intraperitoneal administration of HF-CAR-PMs significantly facilitated the HER2-positive tumour regression in PC mouse model and prolonged the overall survival rate. In addition, the combined use of oxaliplatin and HF-CAR-PMs exhibited significantly augment anti-tumour activity and survival benefit.

CONCLUSIONS

HF-CAR-PMs could represent an exciting therapeutic option for patients with HER2-positive GC cancer, which should be tested in carefully designed clinical trials.

Effects of altered glycolysis levels on CD8+ T cell activation and function

CD8+ T cells are an important component of the body's adaptive immune response. During viral or intracellular bacterial infections, CD8+ T cells are rapidly activated and differentiated to exert their immune function by producing cytokines. Alterations in the glycolysis of CD8+ T cells have an important effect on their activation and function, while glycolysis is important for CD8+ T cell functional failure and recovery. This paper summarizes the importance of CD8+ T cell glycolysis in the immune system. We discuss the link between glycolysis and CD8+ T cell activation, differentiation, and proliferation, and the effect of altered glycolysis on CD8+ T cell function. In addition, potential molecular targets to enhance and restore the immune function of CD8+ T cells by affecting glycolysis and the link between glycolysis and CD8+ T cell senescence are summarized. This review provides new insights into the relationship between glycolysis and CD8+ T cell function, and proposes novel strategies for immunotherapy by targeting glycolysis.

Targeting macrophage Syk enhances responses to immune checkpoint blockade and radiotherapy in high-risk neuroblastoma

Background

Neuroblastoma (NB) is considered an immunologically cold tumor and is usually less responsive to immune checkpoint blockade (ICB). Tumor-associated macrophages (TAMs) are highly infiltrated in NB tumors and promote immune escape and resistance to ICB. Hence therapeutic strategies targeting immunosuppressive TAMs can improve responses to ICB in NB. We recently discovered that spleen tyrosine kinase (Syk) reprograms TAMs toward an immunostimulatory phenotype and enhances T-cell responses in the lung adenocarcinoma model. Here we investigated if Syk is an immune-oncology target in NB and tested whether a novel immunotherapeutic approach utilizing Syk inhibitor together with radiation and ICB could provide a durable anti-tumor immune response in an MYCN amplified murine model of NB.

Methods

Myeloid Syk KO mice and syngeneic MYCN-amplified cell lines were used to elucidate the effect of myeloid Syk on the NB tumor microenvironment (TME). In addition, the effect of Syk inhibitor, R788, on anti-tumor immunity alone or in combination with anti-PDL1 mAb and radiation was also determined in murine NB models. The underlying mechanism of action of this novel therapeutic combination was also investigated.

Results

Herein, we report that Syk is a marker of NB-associated macrophages and plays a crucial role in promoting immunosuppression in the NB TME. We found that the blockade of Syk in NB-bearing mice markedly impairs tumor growth. This effect is facilitated by macrophages that become immunogenic in the absence of Syk, skewing the suppressive TME towards immunostimulation and activating anti-tumor immune responses. Moreover, combining FDA-approved Syk inhibitor, R788 (fostamatinib) along with anti-PDL1 mAb provides a synergistic effect leading to complete tumor regression and durable anti-tumor immunity in mice bearing small tumors (50 mm3) but not larger tumors (250 mm3). However, combining radiation to R788 and anti-PDL1 mAb prolongs the survival of mice bearing large NB9464 tumors.

Conclusion

Collectively, our findings demonstrate the central role of macrophage Syk in NB progression and demonstrate that Syk blockade can "reeducate" TAMs towards immunostimulatory phenotype, leading to enhanced T cell responses. These findings further support the clinical evaluation of fostamatinib alone or with radiation and ICB, as a novel therapeutic intervention in neuroblastoma.

Emerging biomaterials for tumor immunotherapy

BACKGROUND

The immune system interacts with cancer cells in various intricate ways that can protect the individual from overproliferation of cancer cells; however, these interactions can also lead to malignancy. There has been a dramatic increase in the application of cancer immunotherapy in the last decade. However, low immunogenicity, poor specificity, weak presentation efficiency, and off-target side effects still limit its widespread application. Fortunately, advanced biomaterials effectively contribute immunotherapy and play an important role in cancer treatment, making it a research hotspot in the biomedical field.

MAIN BODY

This review discusses immunotherapies and the development of related biomaterials for application in the field. The review first summarizes the various types of tumor immunotherapy applicable in clinical practice as well as their underlying mechanisms. Further, it focuses on the types of biomaterials applied in immunotherapy and related research on metal nanomaterials, silicon nanoparticles, carbon nanotubes, polymer nanoparticles, and cell membrane nanocarriers. Moreover, we introduce the preparation and processing technologies of these biomaterials (liposomes, microspheres, microneedles, and hydrogels) and summarize their mechanisms when applied to tumor immunotherapy. Finally, we discuss future advancements and shortcomings related to the application of biomaterials in tumor immunotherapy.

CONCLUSION

Research on biomaterial-based tumor immunotherapy is booming; however, several challenges remain to be overcome to transition from experimental research to clinical application. Biomaterials have been optimized continuously and nanotechnology has achieved continuous progression, ensuring the development of more efficient biomaterials, thereby providing a platform and opportunity for breakthroughs in tumor immunotherapy.

Maitake α-glucan promotes differentiation of monocytic myeloid-derived suppressor cells into M1 macrophages

AIMS

Myeloid-derived suppressor cells (MDSCs) are major components of the tumor microenvironment and systemically accumulate in tumor-bearing hosts and patients with cancer, facilitating cancer progression. Maitake macromolecular α-glucan YM-2A, isolated from Grifola frondosa, inhibits tumor growth by enhancing immune responses. The present study investigated the effects of YM-2A on the immunosuppressive potential of MDSCs.

MAIN METHODS

YM-2A was orally administered to CT26 tumor-bearing mice, and the number of immune cells in the spleen and tumor was measured. Splenic MDSCs isolated from the CT26 tumor-bearing mice were treated with YM-2A and co-cultured with T cells to measure their inhibitory effect on T cell proliferation. For adoptive transfer of monocytic MDSCs (M-MDSCs), YM-2A-treated M-MDSCs mixed with CT26 cells were implanted subcutaneously in the mice to measure the tumor growth rate.

KEY FINDINGS

YM-2A selectively reduced the accumulation of M-MDSCs but not that of polymorphonuclear MDSCs (PMN-MDSCs) in CT26 tumor-bearing mice. In tumor tissues, YM-2A treatment induced the polarity of immunostimulatory M1-phenotype; furthermore, it increased the infiltration of dendritic, natural killer, and CD4⁺ and CD8⁺ T cells. YM-2A treatment of purified M-MDSCs from CT-26 tumor-bearing mice induced dectin-1-dependent differentiation into M1 macrophages. YM-2A-treated M-MDSCs lost their inhibitory activity against proliferation and activation of CD8⁺ T cells. Furthermore, adoptive transfer of M-MDSCs treated with YM-2A inhibited CT26 tumor growth.

SIGNIFICANCE

YM-2A promotes the differentiation of M-MDSCs into immunostimulatory M1 macrophages, thereby enhancing the efficacy of cancer immunotherapy.

Overcoming Suppressive Tumor Microenvironment by Vaccines in Solid Tumor

Conventional vaccines are widely used to boost human natural ability to defend against foreign invaders, such as bacteria and viruses. Recently, therapeutic cancer vaccines attracted the most attention for anti-cancer therapy. According to the main components, it can be divided into five types: cell, DNA, RNA, peptide, and virus-based vaccines. They mainly perform through two rationales: (1) it trains the host immune system to protect itself and effectively eradicate cancer cells; (2) these vaccines expose the immune system to molecules associated with cancer that enable the immune system to recognize and destroy cancer cells. In this review, we thoroughly summarized the potential strategies and technologies for developing cancer vaccines, which may provide critical achievements for overcoming the suppressive tumor microenvironment through vaccines in solid tumors.

Low-Intensity Focused Ultrasound Produces Immune Response in Pancreatic Cancer

Pancreatic adenocarcinoma is an aggressive malignancy with limited therapeutic treatments available and a 5-y survival less than 10%. Pancreatic cancers have been found to be immunogenically "cold" with a largely immunosuppressive tumor microenvironment. There is emerging evidence that focused ultrasound can induce changes in the tumor microenvironment and have a constructive impact on the effect of immunotherapy. However, the immune cells and timing involved in these effects remain unclear, which is essential to determining how to combine immunotherapy with ultrasound for treatment of pancreatic adenocarcinoma. We used low-intensity focused ultrasound and microbubbles (LoFU + MBs), which can mechanically disrupt cellular membranes and vascular endothelia, to treat subcutaneous pancreatic tumors in C57BL/6 mice. To evaluate the immune cell landscape and expression and/or localization of damage-associated molecular patterns (DAMPs) as a response to ultrasound, we performed flow cytometry and histology on tumors and draining lymph nodes 2 and 15 d post-treatment. We repeated this study on larger tumors and with multiple treatments to determine whether similar or greater effects could be achieved. Two days after treatment, draining lymph nodes exhibited a significant increase in activated antigen presenting cells, such as macrophages, as well as expansion of CD8+ T cells and CD4+ T cells. LoFU + MB treatment caused localized damage and facilitated the translocation of DAMP signals, as reflected by an increase in the cytoplasmic index for high-mobility-group box 1 (HMGB1) at 2 d. Tumors treated with LoFU + MBs exhibited a significant decrease in growth 15 d after treatment, indicating a tumor response that has the potential for additive effects. Our studies indicate that focused ultrasound treatments can cause tumoral damage and changes in macrophages and T cells 2 d post-treatment. The majority of these effects subsided after 15 d with only a single treatment, illustrating the need for additional treatment types and/or combination with immunotherapy. However, when larger tumors were treated, the effects seen at 2 d were diminished, even with an additional treatment. These results provide a working platform for further rational design of focused ultrasound and immunotherapy combinations in poorly immunogenic cancers.

Hyperthermia combined with immune checkpoint inhibitor therapy in the treatment of primary and metastatic tumors

According to the difference in temperature, thermotherapy can be divided into thermal ablation and mild hyperthermia. The main advantage of thermal ablation is that it can efficiently target tumors in situ, while mild hyperthermia has a good inhibitory effect on distant metastasis. There are some similarities and differences between the two therapies with respect to inducing anti-tumor immune responses, but neither of them results in sustained systemic immunity. Malignant tumors (such as breast cancer, pancreatic cancer, nasopharyngeal carcinoma, and brain cancer) are recurrent, highly metastatic, and highly invasive even after treatment, hence a single therapy rarely resolves the clinical issues. A more effective and comprehensive treatment strategy using a combination of hyperthermia and immune checkpoint inhibitor (ICI) therapies has gained attention. This paper summarizes the relevant preclinical and clinical studies on hyperthermia combined with ICI therapies and compares the efficacy of two types of hyperthermia combined with ICIs, in order to provide a better treatment for the recurrence and metastasis of clinically malignant tumors.

Studies on chitosan-

PolyI:C is an immunomodulatory agent that can be used in immunotherapy, but its transportation in the body is hindered. In this study, a chitosan (CS)-graft-polyethyleneimine (PEI) copolymer (C-g-P) is prepared by an N,N′-carbonyl diimidazole (CDI) coupling method as a drug carrier for PolyI:C and simulated antigen ovalbumin (OVA). The results of FT-IR, 1H NMR, elemental analysis and cytotoxicity studies show that PEI is successfully grafted onto CS, and a low cytotoxicity of C-g-P-x (x = 1, 2, 3) with different PEI grafting rates are obtained. C-g-P-x-PolyI:C/OVA (C-g-P-x-PO) (x = 1, 2, 3) nanoparticles are prepared by combining C-g-P-x (x = 1, 2, 3), PolyI:C and OVA by electrostatic self-assembly. The results of agarose gel electrophoresis show that PolyI:C is well coated by the graft copolymer and protected from nuclease degradation. The results show that C-g-P-1-PO nanoparticles with graft copolymer to PolyI:C (N/P) ratios of 80:1 have the best solution stability, and the OVA encapsulation efficiency is 60.6%. The nanoparticles also have a suitable size and regular shape to be absorbed by cells. In vitro immunoassay results show that PolyI:C and OVA-loaded nanoparticles promote the secretion of tumor necrosis factor α (TNF-α) and interferon γ (IFN-γ). CS-g-PEI is a reliable drug carrier for the delivery of PolyI:C and OVA, and it also provides the possibility to carry other drugs.

Immunotherapy: an alternative promising therapeutic approach against cancers

The immune system interacts with cancer cells in multiple intricate ways that can shield the host against hyper-proliferation but can also contribute to malignancy. Understanding the protective roles of the immune system in its interaction with cancer cells can help device new and alternate therapeutic strategies. Many immunotherapeutic methodologies, including adaptive cancer therapy, cancer peptide vaccines, monoclonal antibodies, and immune checkpoint treatment, have transformed the traditional cancer treatment landscape. However, many questions remain unaddressed. The development of personalized combination therapy and neoantigen-based cancer vaccines would be the avant-garde approach to cancer treatment. Desirable chemotherapy should be durable, safe, and target-specific. Managing both tumor (intrinsic factors) and its microenvironment (extrinsic factors) are critical for successful immunotherapy. This review describes current approaches and their advancement related to monoclonal antibody-related clinical trials, new cytokine therapy, a checkpoint inhibitor, adoptive T cell therapy, cancer vaccine, and oncolytic virus.

A graph model of combination therapies

The simultaneous use of multiple medications causes drug-drug interactions (DDI) that impact therapeutic efficacy. Here, we argue that graph theory, in conjunction with game theory and ecosystem theory, can address this issue. We treat the coexistence of multiple drugs as a system in which DDI is modeled by game theory. We develop an ordinary differential equation model to characterize how the concentration of a drug changes as a result of its independent capacity and the dependent influence of other drugs through the metabolic response of the host. We coalesce all drugs into personalized and context-specific networks, which can reveal key DDI determinants of therapeutical efficacy. Our model can quantify drug synergy and antagonism and test the translational success of combination therapies to the clinic.

Modulation of intrinsic inhibitory checkpoints using nano-carriers to unleash NK cell activity

Natural killer (NK) cells provide a powerful weapon mediating immune defense against viral infections, tumor growth, and metastatic spread. NK cells demonstrate great potential for cancer immunotherapy; they can rapidly and directly kill cancer cells in the absence of MHC-dependent antigen presentation and can initiate a robust immune response in the tumor microenvironment (TME). Nevertheless, current NK cell-based immunotherapies have several drawbacks, such as the requirement for ex vivo expansion of modified NK cells, and low transduction efficiency. Furthermore, to date, no clinical trial has demonstrated a significant benefit for NK-based therapies in patients with advanced solid tumors, mainly due to the suppressive TME. To overcome current obstacles in NK cell-based immunotherapies, we describe here a non-viral lipid nanoparticle-based delivery system that encapsulates small interfering RNAs (siRNAs) to gene silence the key intrinsic inhibitory NK cell molecules, SHP-1, Cbl-b, and c-Cbl. The nanoparticles (NPs) target NK cells in vivo, silence inhibitory checkpoint signaling molecules, and unleash NK cell activity to eliminate tumors. Thus, the novel NP-based system developed here may serve as a powerful tool for future NK cell-based therapeutic approaches.

Nobel Prize for immune checkpoint inhibitors, understanding the immunological switching between immunosuppression and autoimmunity

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are a revolutionary form of immunotherapy in cancer. However, the percentage of patients responding to therapy is relatively low, while adverse effects occur in a large number of patients. In addition, the therapeutic mechanisms of ICIs are not yet completely described.

AREAS COVERED

The initial view (articles published in PubMed, Scopus, Web of Science, etc.) was that ICIs increase tumor-specific immunity. Recent data (collected from the same databases) suggest that the ICIs pharmacotherapy actually extends beyond the topic of immune reactivity, including additional immune pathways, such as disrupting immunosuppression and increasing tumor-specific autoimmunity. Unfortunately, there is no clear delimitation between these specific autoimmune reactions that are therapeutically beneficial, and nonspecific autoimmune reactions/toxicity that can be extremely severe side effects.

EXPERT OPINION

Immune checkpoint mechanisms perform a non-selective immune regulation, maintaining a dynamic balance between immunosuppression and autoimmunity. By blocking these mechanisms, ICIs actually perform an immunological reset, decreasing immunosuppression and increasing tumor-specific immunity and predisposition to autoimmunity. The predisposition to autoimmunity induces both side effects and beneficial autoimmunity. Consequently, further studies are necessary to maximize the beneficial tumor-specific autoimmunity, while reducing the counterproductive effect of associated autoimmune toxicity.

A Novel Kinase Inhibitor AX-0085 Inhibits Interferon-γ-Mediated Induction of PD-L1 Expression and Promotes Immune Reaction to Lung Adenocarcinoma Cells

In this study, we describe a novel kinase inhibitor AX-0085 which can suppress the induction of PD-L1 expression by Interferon-γ (IFN-γ) in lung adenocarcinoma (LUAD) cells. AX-0085 effectively blocks JAK2/STAT1 signaling initiated by IFN-γ treatment and prevents nuclear localization of STAT1. Importantly, we demonstrate that AX-0085 reverses the IFN-γ-mediated repression of T cell activation in vitro and enhances the anti-tumor activity of anti-PD-1 antibody in vivo when used in combination. Finally, transcriptomic analyses indicated that AX-0085 is highly specific in targeting the IFN-γ-pathway, thereby raising the possibility of applying this reagent in combination therapy with checkpoint inhibitor antibodies. It may be particularly relevant in cases in which PD-L1-mediated T cell exhaustion leads to immunoevasive phenotypes.

Immune Regulatory Processes of the Tumor Microenvironment under Malignant Conditions

The tumor microenvironment (TME) is a critical regulator of tumor growth, progression, and metastasis. Since immune cells represent a large fraction of the TME, they play a key role in mediating pro- and anti-tumor immune responses. Immune escape, which suppresses anti-tumor immunity, enables tumor cells to maintain their proliferation and growth. Numerous mechanisms, which have been intensively studied in recent years, are involved in this process and based on these findings, novel immunotherapies have been successfully developed. Here, we review the composition of the TME and the mechanisms by which immune evasive processes are regulated. In detail, we describe membrane-bound and soluble factors, their regulation, and their impact on immune cell activation in the TME. Furthermore, we give an overview of the tumor/antigen presentation and how it is influenced under malignant conditions. Finally, we summarize novel TME-targeting agents, which are already in clinical trials for different tumor entities.

Cancer-Immunity Cycle and Therapeutic Interventions- Opportunities for Including Pet Dogs With Cancer

The tumor-immune interplay represents a dynamic series of events executed by cellular and soluble participants that either promote or inhibit successful tumor formation and growth. Throughout a tumor’s development and progression, the host organism’s immune system reacts by generating anti-cancer defenses through various incremental and combinatorial mechanisms, and this reactive orchestration is termed the cancer-immunity cycle. Success or failure of the cancer-immunity cycle dictates the fate of both host and tumor as winner or loser. Insights into how the tumor and host immune system continuously adapt to each other throughout the lifecycle of the tumor is necessary to rationally develop new effective immunotherapies. Additionally, the evolving nature of the cancer-immunity cycle necessitates therapeutic agility, requiring real-time serial assessment of immunobiologic markers that permits tailoring of therapies to the everchanging tumor immune microenvironment. In order to accelerate advances in the field of immuno-oncology, this review summarizes the steps comprising the cancer-immunity cycle, and underscores key breakpoints in the cycle that either favor cancer regression or progression, as well as shaping of the tumor microenvironment and associated immune phenotypes. Furthermore, specific large animal models of spontaneous cancers that are deemed immunogenic will be reviewed and proposed as unique resources for validating investigational immunotherapeutic protocols that are informed by the cancer-immunity cycle. Collectively, this review will provide a progressive look into the dynamic interplay between tumor and host immune responses and raise awareness for how large animal models can be included for developing combinatorial and sequenced immunotherapies to maximizing favorable treatment outcomes.

Design, synthesis, and structure-activity relationship of PD-1/PD-L1 inhibitors with a benzo[d]isoxazole scaffold

Blocking the programmed cell death protein 1 (PD-1) and programmed death-ligand (PD-L1) interaction has emerged as one of the most promising treatments for cancer immunotherapy. A novel series of compounds bearing a benzo[d]isoxazole scaffold was developed as PD-1/PD-L1 inhibitors, among them, compound P20 exhibited the most potent inhibitory activity, with an IC₅₀ value of 26.8 nM. The preliminary structure-activity relationship was also investigated. The docking analysis of compound P20 with the PD-L1 dimer complex (PDB ID: 5j89) indicated that compound P20 was bound to the PD-L1 dimer with high affinity. These results suggest that compound P20 is a promising lead compound for the development of inhibitors of the PD-1/PD-L1 interaction.

Alternative Energy: Breaking Down the Diverse Metabolic Features of Lung Cancers

Metabolic reprogramming is a hallmark of cancer initiation, progression, and relapse. From the initial observation that cancer cells preferentially ferment glucose to lactate, termed the Warburg effect, to emerging evidence indicating that metabolic heterogeneity and mitochondrial metabolism are also important for tumor growth, the complex mechanisms driving cancer metabolism remain vastly unknown. These unique shifts in metabolism must be further investigated in order to identify unique therapeutic targets for individuals afflicted by this aggressive disease. Although novel therapies have been developed to target metabolic vulnerabilities in a variety of cancer models, only limited efficacy has been achieved. In particular, lung cancer metabolism has remained relatively understudied and underutilized for the advancement of therapeutic strategies, however recent evidence suggests that lung cancers have unique metabolic preferences of their own. This review aims to provide an overview of essential metabolic mechanisms and potential therapeutic agents in order to increase evidence of targeted metabolic inhibition for the treatment of lung cancer, where novel therapeutics are desperately needed.

Preparation and evaluation of dabrafenib-loaded, CD47-conjugated human serum albumin-based nanoconstructs for chemoimmunomodulation

The transmembrane proteins, CD47 and signal-regulatory protein α are overexpressed in cancer cells and macrophages, respectively, and facilitate the escape of cancer cells from macrophage-mediated phagocytosis. The immunomodulatory and targeting properties of CD47, the chemotherapeutic effects of dabrafenib (D), and the anti-programmed death-1 antibodies (PD-1) pave the way for effective chemoimmunomodulation-mediated anticancer combination therapy. In this study, CD47-conjugated, D-loaded human serum albumin (HSA) nanosystems were fabricated by modified nanoparticle albumin-bound technology. Cis-aconityl-PEG-maleimide (CA), an acid-labile linker, was used to conjugate D@HSA and CD47; the resultant CD47-CA@D@HSA exhibited tumor-specificity through receptor targeting, as well as preferential cleavage and drug release in the acidic tumor microenvironment (pH 5) compared to normal physiological pH conditions (pH 6.5, 7.4). The successful preparation of nanosized (∼220 nm), narrowly dispersed (∼0.13) CD47-CA@D@HSA was proven by physicochemical characterization. In vitro and in vivo internalization, accumulation, cytotoxicity, and apoptosis were observed to be higher with CD47-conjugated nanoconstructs, than with free D or non-targeted nanoconstructs. CD47-CA@D@HSA was found to promote the infiltration of cytotoxic T cells and tumor-associated macrophages into tumors and improve in vivo tumor inhibition. Administration in combination with PD-1 further improved antitumor efficacy by promoting immune responses that blocked the immune checkpoint. No signs of toxicity were seen in mice treated with the nanoconstructs; the formulation was, therefore, thought to be biocompatible and as having potential for clinical use. The targeted chemoimmunomodulation achieved by this combination therapy was found to combat major immunosuppressive facets, making it a viable candidate for use in the treatment of cancer.

Antidepressants with anti-tumor potential in treating glioblastoma: A narrative review

Glioblastoma multiforme (GBM) is known as the deadliest form of brain tumor. In addition, its high treatment resistance, heterogeneity, and invasiveness make it one of the most challenging tumors. Depression is a common psychological disorder among patients with cancer, especially GBM. Due to the high occurrence rates of depression in GBM patients and the overlap of molecular and cellular mechanisms involved in the pathogenesis of these diseases, finding antidepressants with antitumor effects could be considered as an affordable strategy for the treatment of GBM. Antidepressants exert their antitumor properties through different mechanisms. According to available evidence in this regard, some of them can eliminate the adverse effects resulting from chemo-radiotherapy in several cancers along with their synergistic effects caused by chemotherapy. Therefore, providing comprehensive insight into this issue would guide scientists and physicians in developing further preclinical studies and clinical trials, in order to evaluate antidepressants' antitumor potential. Considering that no narrative review has been recently published on this issue, specifically on these classes of drugs, we present this article with the purpose of describing the antitumor cellular mechanisms of three classes of antidepressants as follows: tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAOIs) in GBM.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Anticancer Activity of Two Novel Hydroxylated Biphenyl Compounds toward Malignant Melanoma Cells

Melanoma, the deadliest form of skin cancer, is still one of the most difficult cancers to treat despite recent advances in targeted and immune therapies. About 50% of advanced melanoma do not benefit of such therapies, and novel treatments are requested. Curcumin and its analogs have shown good anticancer properties and are being considered for use in combination with or sequence to recent therapies to improve patient outcomes. Our group previously published the synthesis and anticancer activity characterization of a novel curcumin-related compound against melanoma and neuroblastoma cells (D6). Here, two hydroxylated biphenyl compounds-namely, compounds 11 and 12-were selected among a small collection of previously screened C2-symmetric hydroxylated biphenyls structurally related to D6 and curcumin, showing the best antitumor potentiality against melanoma cells (IC50 values of 1.7 ± 0.5 μM for 11 and 2.0 ± 0.7 μM for 12) and no toxicity of normal fibroblasts up to 32 µM. Their antiproliferative activity was deeply characterized on five melanoma cell lines by performing dose-response and clonal growth inhibition assays, which revealed long-lasting and irreversible effects for both compounds. Apoptosis induction was ascertained by the annexin V and TUNEL assays, whereas Western blotting showed caspase activation and PARP cleavage. A cell cycle analysis, following cell treatments with either compound 11 or 12, highlighted an arrest in the G2/M transition. Taking all this evidence together, 11 and 12 were shown to be good candidates as lead compounds to develop new anticancer drugs against malignant melanoma.

Combined Effects of Myeloid Cells in the Neuroblastoma Tumor Microenvironment

Despite multimodal treatment, survival chances for high-risk neuroblastoma patients remain poor. Immunotherapeutic approaches focusing on the activation and/or modification of host immunity for eliminating tumor cells, such as chimeric antigen receptor (CAR) T cells, are currently in development, however clinical trials have failed to reproduce the preclinical results. The tumor microenvironment is emerging as a major contributor to immune suppression and tumor evasion in solid cancers and thus has to be overcome for therapies relying on a functional immune response. Among the cellular components of the neuroblastoma tumor microenvironment, suppressive myeloid cells have been described as key players in inhibition of antitumor immune responses and have been shown to positively correlate with more aggressive disease, resistance to treatments, and overall poor prognosis. This review article summarizes how neuroblastoma-driven inflammation induces suppressive myeloid cells in the tumor microenvironment and how they in turn sustain the tumor niche through suppressor functions, such as nutrient depletion and generation of oxidative stress. Numerous preclinical studies have suggested a range of drug and cellular therapy approaches to overcome myeloid-derived suppression in neuroblastoma that warrant evaluation in future clinical studies.

Functionalized Reduced Graphene Oxide as a Versatile Tool for Cancer Therapy

Cancer is one of the deadliest diseases in human history with extremely poor prognosis. Although many traditional therapeutic modalities-such as surgery, chemotherapy, and radiation therapy-have proved to be successful in inhibiting the growth of tumor cells, their side effects may vastly limited the actual benefits and patient acceptance. In this context, a nanomedicine approach for cancer therapy using functionalized nanomaterial has been gaining ground recently. Considering the ability to carry various anticancer drugs and to act as a photothermal agent, the use of carbon-based nanomaterials for cancer therapy has advanced rapidly. Within those nanomaterials, reduced graphene oxide (rGO), a graphene family 2D carbon nanomaterial, emerged as a good candidate for cancer photothermal therapy due to its excellent photothermal conversion in the near infrared range, large specific surface area for drug loading, as well as functional groups for functionalization with molecules such as photosensitizers, siRNA, ligands, etc. By unique design, multifunctional nanosystems could be designed based on rGO, which are endowed with promising temperature/pH-dependent drug/gene delivery abilities for multimodal cancer therapy. This could be further augmented by additional advantages offered by functionalized rGO, such as high biocompatibility, targeted delivery, and enhanced photothermal effects. Herewith, we first provide an overview of the most effective reducing agents for rGO synthesis via chemical reduction. This was followed by in-depth review of application of functionalized rGO in different cancer treatment modalities such as chemotherapy, photothermal therapy and/or photodynamic therapy, gene therapy, chemotherapy/phototherapy, and photothermal/immunotherapy.

Druggable genome and precision medicine in cancer: current challenges

The past decades have seen tremendous developments with respect to "specific" therapeutics that target key signaling molecules to conquer cancer. The key advancements with multiomics technologies, especially genomics, have allowed physicians and molecular oncologists to design "tailor-made" solutions to the specific oncogenes that are deregulated in individual patients, a strategy which has turned out to be successful though the patients quickly develop resistance. The swift integration of multidisciplinary approaches has led to the development of "next generation" therapeutics and, with synergistic therapeutic regimes combined with immune checkpoint inhibitors to reactivate the dampened immune response, has provided the much-needed promise for cancer patients. Despite these advances, a large portion of the druggable genome remains understudied, and the role of druggable genome in the immune system needs further attention. Establishment of patient-derived organoid models has fastened the preclinical validation of novel therapeutics for swift clinical translation. We summarized the current advances and challenges and also stress the importance of biobanking and collection of longitudinal data sets with structured clinical information, as well as the critical role these "high content data sets" will play in designing new therapeutic regimes in a tailor-made fashion.

Patents, ethics, biosafety and regulation using CRISPR technology

In this review chapter, we provide full comprehensive analysis on the patent, ethics and biosafety regulation with respect to the application of CRISPR technology in mammalian systems. We focused on recent development in CRISPR technology and its patent landscape between countries such as US, European Union, China and Australia. Further, we emphasized on the current scenarios on the ethics regulations with respect to CRISPR research, its applicability in patent and technology transfer. Finally, we elaborated on the biosafety regulation on CRISPR/Cas9 technology application in both mammalian and non-mammalian host system.

BTK Inhibition Reverses MDSC-Mediated Immunosuppression and Enhances Response to Anti-PDL1 Therapy in Neuroblastoma

MDSCs are immune cells of myeloid lineage that plays a key role in promoting tumor growth. The expansion of MDSCs in tumor-bearing hosts reduces the efficacy of checkpoint inhibitors and CAR-T therapies, and hence strategies that deplete or block the recruitment of MDSCs have shown benefit in improving responses to immunotherapy in various cancers, including NB. Ibrutinib, an irreversible molecular inhibitor of BTK, has been widely studied in B cell malignancies, and recently, this drug is repurposed for the treatment of solid tumors. Herein we report that BTK is highly expressed in both granulocytic and monocytic murine MDSCs isolated from mice bearing NB tumors, and its increased expression correlates with a poor relapse-free survival probability of NB patients. Moreover, in vitro treatment of murine MDSCs with ibrutinib altered NO production, decreased mRNA expression of Ido, Arg, Tgfβ, and displayed defects in T-cell suppression. Consistent with these findings, in vivo inhibition of BTK with ibrutinib resulted in reduced MDSC-mediated immune suppression, increased CD8+ T cell infiltration, decreased tumor growth, and improved response to anti-PDL1 checkpoint inhibitor therapy in a murine model of NB. These results demonstrate that ibrutinib modulates immunosuppressive functions of MDSC and can be used either alone or in combination with immunotherapy for augmenting antitumor immune responses in NB.

Chimeric antigen receptor T-cell therapy for melanoma

INTRODUCTION

In recent years, chimeric antigen receptor (CAR) T cell therapy has emerged as a cancer treatment. After initial therapeutic success for hematologic malignancies, this approach has been extended for the treatment of solid tumors including melanoma.

AREAS COVERED

T cells need to be reprogramed to recognize specific antigens expressed only in tumor cells, a difficult problem since cancer cells are simply transformed normal cells. Tumor antigens, namely, CSPG4, CD70, and GD2 have been targeted by CAR-T cells for melanoma. Moreover, different co-stimulatory signaling domains need to be selected to direct T cell fate. In this review, various approaches for the treatment of melanoma and their effectiveness are comprehensively reviewed and the current status, challenges, and future perspective of CAR-T cell therapy for melanoma are discussed. Literature search was accomplished in three databases (PubMed, Google scholar, and Clinicaltrials.gov). Published papers and clinical trials were screened and relevant documents were included by checking pre-defined eligibility criteria.

EXPERT OPINION

Despite obstacles and the risk of adverse events, CAR T cell therapy could be used for patients with treatment-resistant cancer. Clinical trials are underway to determine the efficacy of this approach for the treatment of melanoma.

Synthesis of Hydroxylated Biphenyl Derivatives Bearing an α,β-Unsaturated Ketone as a Lead Structure for the Development of Drug Candidates against Malignant Melanoma

A small collection of C₂ -symmetric hydroxylated biphenyl derivatives featuring an α,β-unsaturated ketone as a lead structure was prepared, and the capacity of these compounds to act as antiproliferative agents against four human malignant melanoma cell lines was assayed. The prodrug approach was applied in order to improve the delivery of compounds into the cell by modulation of the phenolic hydroxy protecting group. The hydroxylated biphenyl structure bearing an α,β-unsaturated ketone and a phenolic-O-prenylated chain was found to facilitate the delivery of the molecule and interactions with biological targets. Four compounds showed antiproliferative activity resulting in IC₅₀ values in the range of 1.2 to 2.8 μM.

Advances in Magnetic Nanoparticle-Mediated Cancer Immune-Theranostics

Cancer immunotherapy is a cutting-edge strategy that eliminates cancer cells by amplifying the host's immune system. However, the low response rate and risks of inducing systemic toxicity have raised uncertainty in the treatment. Magnetic nanoparticles (MNPs) as a versatile theranostic tool can be used to target delivery of multiple immunotherapeutics and monitor cell/tissue responses. These capabilities enable the real-time characterization of the factors that contribute to immunoactivity so that future treatments can be optimized. The magnetic properties of MNPs further allow the implementation of magnetic navigation and magnetic hyperthermia for boosting the efficacy of immunotherapy. The multimodal approach opens an avenue to induce robust immune responses, minimize safety issues, and monitor immune activities simultaneously. Thus, the object of this review is to provide an overview of the burgeoning fields and to highlight novel technologies for next-generation immunotherapy. The review further correlates the properties of MNPs with the latest treatment strategies to explore the crosstalk between magnetic nanomaterials and the immune system. This comprehensive review of MNP-derived immunotherapy covers the obstacles and opportunities for future development and clinical translation.

Recent Progress in the Synergistic Combination of Nanoparticle-Mediated Hyperthermia and Immunotherapy for Treatment of Cancer

Immunotherapy has demonstrated great clinical success in certain cancers, driven primarily by immune checkpoint blockade and adoptive cell therapies. Immunotherapy can elicit strong, durable responses in some patients, but others do not respond, and to date immunotherapy has demonstrated success in only a limited number of cancers. To address this limitation, combinatorial approaches with chemo- and radiotherapy have been applied in the clinic. Extensive preclinical evidence suggests that hyperthermia therapy (HT) has considerable potential to augment immunotherapy with minimal toxicity. This progress report will provide a brief overview of immunotherapy and HT approaches and highlight recent progress in the application of nanoparticle (NP)-based HT in combination with immunotherapy. NPs allow for tumor-specific targeting of deep tissue tumors while potentially providing more even heating. NP-based HT increases tumor immunogenicity and tumor permeability, which improves immune cell infiltration and creates an environment more responsive to immunotherapy, particularly in solid tumors.

Macrocybin, a Natural Mushroom Triglyceride, Reduces Tumor Growth In Vitro and In Vivo through Caveolin-Mediated Interference with the Actin Cytoskeleton

Mushrooms have been used for millennia as cancer remedies. Our goal was to screen several mushroom species from the rainforests of Costa Rica, looking for new antitumor molecules. Mushroom extracts were screened using two human cell lines: A549 (lung adenocarcinoma) and NL20 (immortalized normal lung epithelium). Extracts able to kill tumor cells while preserving non-tumor cells were considered “anticancer”. The mushroom with better properties was Macrocybe titans. Positive extracts were fractionated further and tested for biological activity on the cell lines. The chemical structure of the active compound was partially elucidated through nuclear magnetic resonance, mass spectrometry, and other ancillary techniques. Chemical analysis showed that the active molecule was a triglyceride containing oleic acid, palmitic acid, and a more complex fatty acid with two double bonds. The synthesis of all possible triglycerides and biological testing identified the natural compound, which was named Macrocybin. A xenograft study showed that Macrocybin significantly reduces A549 tumor growth. In addition, Macrocybin treatment resulted in the upregulation of Caveolin-1 expression and the disassembly of the actin cytoskeleton in tumor cells (but not in normal cells). In conclusion, we have shown that Macrocybin constitutes a new biologically active compound that may be taken into consideration for cancer treatment.

Discovery of Potent and Selective 7-Azaindole Isoindolinone-Based PI3Kγ Inhibitors

The successful application of immunotherapy in the treatment of cancer relies on effective engagement of immune cells in the tumor microenvironment. Phosphoinositide 3-kinase γ (PI3Kγ) is highly expressed in tumor-associated macrophages, and its expression levels are associated with tumor immunosuppression and growth. Selective inhibition of PI3Kγ offers a promising strategy in immuno-oncology, which has led to the development of numerous potent PI3Kγ inhibitors with variable selectivity profiles. To facilitate further investigation of the therapeutic potential of PI3Kγ inhibition, we required a potent and PI3Kγ-selective tool compound with sufficient metabolic stability for use in future in vivo studies. Herein, we describe some of our efforts to realize this goal through the systematic study of SARs within a series of 7-azaindole-based PI3Kγ inhibitors. The large volume of data generated from this study helped guide our subsequent lead optimization efforts and will inform further development of PI3Kγ-selective inhibitors for use in immunomodulation.

Promising potential of [177Lu]Lu-DOTA-folate to enhance tumor response to immunotherapy-a preclinical study using a syngeneic breast cancer model

PURPOSE

It was previously demonstrated that radiation effects can enhance the therapy outcome of immune checkpoint inhibitors. In this study, a syngeneic breast tumor mouse model was used to investigate the effect of [¹⁷⁷Lu]Lu-DOTA-folate as an immune stimulus to enhance anti-CTLA-4 immunotherapy.

METHODS

In vitro and in vivo studies were performed to characterize NF9006 breast tumor cells with regard to folate receptor (FR) expression and the possibility of tumor targeting using [¹⁷⁷Lu]Lu-DOTA-folate. A preclinical therapy study was performed over 70 days with NF9006 tumor-bearing mice that received vehicle only (group A); [¹⁷⁷Lu]Lu-DOTA-folate (5 MBq; 3.5 Gy absorbed tumor dose; group B); anti-CTLA-4 antibody (3 × 200 μg; group C), or both agents (group D). The mice were monitored regarding tumor growth over time and signs indicating adverse events of the treatment.

RESULTS

[¹⁷⁷Lu]Lu-DOTA-folate bound specifically to NF9006 tumor cells and tissue in vitro and accumulated in NF9006 tumors in vivo. The treatment with [¹⁷⁷Lu]Lu-DOTA-folate or an anti-CTLA-4 antibody had only a minor effect on NF9006 tumor growth and did not substantially increase the median survival time of mice (23 day and 19 days, respectively) as compared with untreated controls (12 days). [¹⁷⁷Lu]Lu-DOTA-folate sensitized, however, the tumors to anti-CTLA-4 immunotherapy, which became obvious by reduced tumor growth and, hence, a significantly improved median survival time of mice (> 70 days). No obvious signs of adverse effects were observed in treated mice as compared with untreated controls.

CONCLUSION

Application of [¹⁷⁷Lu]Lu-DOTA-folate had a positive effect on the therapy outcome of anti-CTLA-4 immunotherapy. The results of this study may open new perspectives for future clinical translation of folate radioconjugates.

A Middle-Out Modeling Strategy to Extend a Colon Cancer Logical Model Improves Drug Synergy Predictions in Epithelial-Derived Cancer Cell Lines

Cancer is a heterogeneous and complex disease and one of the leading causes of death worldwide. The high tumor heterogeneity between individuals affected by the same cancer type is accompanied by distinct molecular and phenotypic tumor profiles and variation in drug treatment response. In silico modeling of cancer as an aberrantly regulated system of interacting signaling molecules provides a basis to enhance our biological understanding of disease progression, and it offers the means to use computer simulations to test and optimize drug therapy designs on particular cancer types and subtypes. This sets the stage for precision medicine: the design of treatments tailored to individuals or groups of patients based on their tumor-specific molecular cancer profiles. Here, we show how a relatively large manually curated logical model can be efficiently enhanced further by including components highlighted by a multi-omics data analysis of data from Consensus Molecular Subtypes covering colorectal cancer. The model expansion was performed in a pathway-centric manner, following a partitioning of the model into functional subsystems, named modules. The resulting approach constitutes a middle-out modeling strategy enabling a data-driven expansion of a model from a generic and intermediate level of molecular detail to a model better covering relevant processes that are affected in specific cancer subtypes, comprising 183 biological entities and 603 interactions between them, partitioned in 25 functional modules of varying size and structure. We tested this model for its ability to correctly predict drug combination synergies, against a dataset of experimentally determined cell growth responses with 18 drugs in all combinations, on eight cancer cell lines. The results indicate that the extended model had an improved accuracy for drug synergy prediction for the majority of the experimentally tested cancer cell lines, although significant improvements of the model's predictive performance are still needed. Our study demonstrates how a tumor-data driven middle-out approach toward refining a logical model of a biological system can further customize a computer model to represent specific cancer cell lines and provide a basis for identifying synergistic effects of drugs targeting specific regulatory proteins. This approach bridges between preclinical cancer model data and clinical patient data and may thereby ultimately be of help to develop patient-specific in silico models that can steer treatment decisions in the clinic.

Cytotoxic CD8+ T cells in cancer and cancer immunotherapy

The functions of, and interactions between, the innate and adaptive immune systems are vital for anticancer immunity. Cytotoxic T cells expressing cell-surface CD8 are the most powerful effectors in the anticancer immune response and form the backbone of current successful cancer immunotherapies. Immune-checkpoint inhibitors are designed to target immune-inhibitory receptors that function to regulate the immune response, whereas adoptive cell-transfer therapies use CD8⁺ T cells with genetically modified receptors—chimaeric antigen receptors—to specify and enhance CD8⁺ T-cell functionality. New generations of cytotoxic T cells with genetically modified or synthetic receptors are being developed and evaluated in clinical trials. Furthermore, combinatory regimens might optimise treatment effects and reduce adverse events. This review summarises advances in research on the most prominent immune effectors in cancer and cancer immunotherapy, cytotoxic T cells, and discusses possible implications for future cancer treatment.

QSP-IO: A Quantitative Systems Pharmacology Toolbox for Mechanistic Multiscale Modeling for Immuno-Oncology Applications

Immunotherapy has shown great potential in the treatment of cancer; however, only a fraction of patients respond to treatment, and many experience autoimmune‐related side effects. The pharmaceutical industry has relied on mathematical models to study the behavior of candidate drugs and more recently, complex, whole‐body, quantitative systems pharmacology (QSP) models have become increasingly popular for discovery and development. QSP modeling has the potential to discover novel predictive biomarkers as well as test the efficacy of treatment plans and combination therapies through virtual clinical trials. In this work, we present a QSP modeling platform for immuno‐oncology (IO) that incorporates detailed mechanisms for important immune interactions. This modular platform allows for the construction of QSP models of IO with varying degrees of complexity based on the research questions. Finally, we demonstrate the use of the platform through two example applications of immune checkpoint therapy.

"Re-educating" Tumor Associated Macrophages as a Novel Immunotherapy Strategy for Neuroblastoma

Neuroblastoma is the most common extracranial pediatric tumor and often presents with metastatic disease, and patients with high-risk neuroblastoma have survival rates of ~50%. Neuroblastoma tumorigenesis is associated with the infiltration of various types of immune cells, including myeloid derived suppressor cells, tumor associated macrophages (TAMs), and regulatory T cells, which foster tumor growth and harbor immunosuppressive functions. In particular, TAMs predict poor clinical outcomes in neuroblastoma, and among these immune cells, TAMs with an M2 phenotype comprise an immune cell population that promotes tumor metastasis, contributes to immunosuppression, and leads to failure of radiation or checkpoint inhibitor therapy. This review article summarizes the role of macrophages in tumor angiogenesis, metastasis, and immunosuppression in neuroblastoma and discusses the recent advances in "macrophage-targeting strategies" in neuroblastoma with a focus on three aspects: (1) inhibition of macrophage recruitment, (2) targeting macrophage survival, and (3) reprogramming of macrophages into an immunostimulatory phenotype.

Anti-angiogenic Agents in Combination With Immune Checkpoint Inhibitors: A Promising Strategy for Cancer Treatment

Advances in cancer immunity have promoted a major breakthrough in the field of cancer therapy. This is mainly associated with the successful development of immune checkpoint inhibitors (ICIs) for multiple types of human tumors. Blockade with different ICIs, including programmed cell death 1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, may activate the immune system of the host against malignant cells. However, only a subgroup of patients with cancer would benefit from immune checkpoint blockade. Some patients experience primary resistance to initial immunotherapy, and a majority eventually develop acquired resistance to ICIs. However, the mechanisms involved in the development of drug resistance to immune checkpoint blockade remain unclear. Recent studies supported that combination of ICIs and anti-angiogenic agents could be a promising therapeutic strategy for overcoming the low efficacy of ICIs. Moreover, through their direct anti-cancer effect by inhibiting tumor growth and metastasis, anti-angiogenic drugs reprogram the tumor milieu from an immunosuppressive to an immune permissive microenvironment. Activated immunity by immune checkpoint blockade also facilitates anti-angiogenesis by downregulating the expression of vascular endothelial growth factor and alleviating hypoxia condition. Many clinical trials showed an improved anti-cancer efficacy and prolonged survival following the addition of anti-angiogenic agents to ICIs. This review summarizes the current understanding and clinical development of combination therapy with immune checkpoint blockade and anti-angiogenic strategy.

Necroptosis in Immuno-Oncology and Cancer Immunotherapy

Immune-checkpoint blockers (ICBs) have revolutionized oncology and firmly established the subfield of immuno-oncology. Despite this renaissance, a subset of cancer patients remain unresponsive to ICBs due to widespread immuno-resistance. To "break" cancer cell-driven immuno-resistance, researchers have long floated the idea of therapeutically facilitating the immunogenicity of cancer cells by disrupting tumor-associated immuno-tolerance via conventional anticancer therapies. It is well appreciated that anticancer therapies causing immunogenic or inflammatory cell death are best positioned to productively activate anticancer immunity. A large proportion of studies have emphasized the importance of immunogenic apoptosis (i.e., immunogenic cell death or ICD); yet, it has also emerged that necroptosis, a programmed necrotic cell death pathway, can also be immunogenic. Emergence of a proficient immune profile for necroptosis has important implications for cancer because resistance to apoptosis is one of the major hallmarks of tumors. Putative immunogenic or inflammatory characteristics driven by necroptosis can be of great impact in immuno-oncology. However, as is typical for a highly complex and multi-factorial disease like cancer, a clear cause versus consensus relationship on the immunobiology of necroptosis in cancer cells has been tough to establish. In this review, we discuss the various aspects of necroptosis immunobiology with specific focus on immuno-oncology and cancer immunotherapy.

Combination of Immune Checkpoint Inhibitors with Chemotherapy in Lung Cancer

Tremendous progress has been achieved in the field of immune checkpoint inhibitors (ICIs) therapy in lung cancer in recent years. To generate robust, long-lasting anti-tumor immune responses in lung cancer patients, combinational ICI therapies have been explored deeply. Conventionally, chemotherapy was considered as immunosuppressive. It is now recognized that chemotherapy could also reinstate cancer cell immune-surveillance and enable the perception of cancer cells as dangerous. That is to say that chemotherapeutic drugs are not only a source of direct cytotoxic effects but also an adjuvant for anti-tumor immunity. Recently, multiple clinical studies of ICIs combined with chemotherapeutic drugs have been explored and proved effective. However, there are still crucial questions that are not well addressed, such as the optimal dose and schedule for a given combination may differ across disease indications, and the appropriate strategy of selecting patient population that can benefit from ICIs remains unclear. To facilitate more rational lung cancer ICIs therapy development, this review summarizes the immune-regulatory effects and related mechanisms of chemotherapeutic drugs and the clinical progress of ICIs and their combination with chemotherapies in lung cancer treatment.

Targeting the Tumor Microenvironment in Neuroblastoma: Recent Advances and Future Directions

Neuroblastoma (NB) is the most common pediatric tumor malignancy that originates from the neural crest and accounts for more than 15% of all the childhood deaths from cancer. The neuroblastoma cancer research has long been focused on the role of MYCN oncogene amplification and the contribution of other genetic alterations in the progression of this malignancy. However, it is now widely accepted that, not only tumor cells, but the components of tumor microenvironment (TME), including extracellular matrix, stromal cells and immune cells, also contribute to tumor progression in neuroblastoma. The complexity of different components of tumor stroma and their resemblance with surrounding normal tissues pose huge challenges for therapies targeting tumor microenvironment in NB. Hence, the detailed understanding of the composition of the TME of NB is crucial to improve existing and future potential immunotherapeutic approaches against this childhood cancer. In this review article, I will discuss different components of the TME of NB and the recent advances in the strategies, which are used to target the tumor microenvironment in neuroblastoma.

Dianhydrogalactitol synergizes with topoisomerase poisons to overcome DNA repair activity in tumor cells

1,2:5,6-Dianhydrogalactitol (DAG) is a bi-functional DNA-targeting agent currently in phase II clinical trial for treatment of temozolomide-resistant glioblastoma (GBM). In the present study, we investigated the cytotoxic activity of DAG alone or in combination with common chemotherapy agents in GBM and prostate cancer (PCa) cells, and determined the impact of DNA repair pathways on DAG-induced cytotoxicity. We found that DAG produced replication-dependent DNA lesions decorated with RPA32, RAD51, and γH2AX foci. DAG-induced cytotoxicity was unaffected by MLH1, MSH2, and DNA-PK expression, but was enhanced by knockdown of BRCA1. Acting in S phase, DAG displayed selective synergy with topoisomerase I (camptothecin and irinotecan) and topoisomerase II (etoposide) poisons in GBM, PCa, and lung cancer cells with no synergy observed for docetaxel. Importantly, DAG combined with irinotecan treatment enhanced tumor responses and prolonged survival of tumor-bearing mice. This work provides mechanistic insight into DAG cytotoxicity in GBM and PCa cells and offers a rational for exploring combination regimens with topoisomerase I/II poisons in future clinical trials.

p110δ PI3K as a therapeutic target of solid tumours

From the time of first characterization of PI3K as a heterodimer made up of a p110 catalytic subunit and a regulatory subunit, a wealth of evidence have placed the class IA PI3Ks at the forefront of drug development for the treatment of various diseases including cancer. The p110α isoform was quickly brought at the centre of attention in the field of cancer research by the discovery of cancer-specific gain-of-function mutations in PIK3CA gene in a range of human solid tumours. In contrast, p110δ PI3K was placed into the spotlight of immunity, inflammation and haematologic malignancies because of the preferential expression of this isoform in leucocytes and the rare mutations in PIK3CD gene. The last decade, however, several studies have provided evidence showing that the correlation between the PIK3CA mutations and the response to PI3K inhibition is less clear than originally considered, whereas concurrently an unexpected role of p110δ PI3K in solid tumours has being emerging. While PIK3CD is mostly non-mutated in cancer, the expression levels of p110δ protein seem to act as an intrinsic cancer-causing driver in various solid tumours including breast, prostate, colorectal and liver cancer, Merkel-Cell carcinoma, glioblastoma and neurobalstoma. Furthermore, p110δ selective inhibitors are being studied as potential single agent treatments or as combination partners in attempt to improve cancer immunotherapy, with both strategies to shown great promise for the treatment of several solid tumours. In this review, we discuss the evidence implicating the p110δ PI3K in human solid tumours, their impact on the current state of the field and the potential of using p110δ-selective inhibitors as monotherapy or combined therapy in different cancer contexts.