The DNA damage response arouses the immune system

Oncolytic adenovirus coding for shedding-resistant MICA enhances immune responses against tumors

Cancer immunotherapies strive to overcome tumor-induced immune suppression and activate antitumor immune responses. Although cytotoxic T lymphocytes (CTLs) play a pivotal role in this process, natural killer (NK) cells have also demonstrated remarkable tumor-killing abilities, given their ability to discriminate tumor cells from normal cells and mediate specific antitumoral cytotoxicity. NK cells activation depends on a balance between activation and inhibition signals from several ligands/receptors. Among them, MICA/NKG2D axis is a master regulator of NK activation. MHC class I chain-related polypeptide A (MICA) expression is upregulated by many tumor cell lines and primary tumors and serves as a ligand for the activating NK group 2D (NKG2D) receptor on NK cells and subpopulations of T cells. However, cancer cells can cleave MICA, making it soluble and de-targeting tumor cells from NK cells, leading to tumor immune escape.In this study, we present ICOVIR15KK-MICAMut, an oncolytic adenovirus (OAdv) armed with a transgene encoding a non-cleavable MICA to promote NK-mediated cell-killing capacity and activate the immune response against cancer cells. We first demonstrated the correct MICA overexpression from infected cells. Moreover, our MICA-expressing OAdv promotes higher NK activation and killing capacity than the non-armed virus in vitro. In addition, the armed virus also demonstrated significant antitumor activity in immunodeficient mice in the presence of human PBMCs, indicating the activation of human NK cells. Finally, OAdv-MICA overexpression in immunocompetent tumor-bearing mice elicits tumor-specific immune response resulting in a greater tumor growth control.In summary, this study highlights the significance of NK cells in cancer immunotherapy and presents an innovative approach using a modified oncolytic virus to enhance NK cell activation and antitumor immune response. These findings suggest promising potential for future research and clinical applications.

The cell stress and immunity cycle in cancer: Toward next generation of cancer immunotherapy

The cellular stress and immunity cycle is a cornerstone of organismal homeostasis. Stress activates intracellular and intercellular communications within a tissue or organ to initiate adaptive responses aiming to resolve the origin of this stress. If such local measures are unable to ameliorate this stress, then intercellular communications expand toward immune activation with the aim of recruiting immune cells to effectively resolve the situation while executing tissue repair to ameliorate any damage and facilitate homeostasis. This cellular stress-immunity cycle is severely dysregulated in diseased contexts like cancer. On one hand, cancer cells dysregulate the normal cellular stress responses to reorient them toward upholding growth at all costs, even at the expense of organismal integrity and homeostasis. On the other hand, the tumors severely dysregulate or inhibit various components of organismal immunity, for example, by facilitating immunosuppressive tumor landscape, lowering antigenicity, and increasing T-cell dysfunction. In this review we aim to comprehensively discuss the basis behind tumoral dysregulation of cellular stress-immunity cycle. We also offer insights into current understanding of the regulators and deregulators of this cycle and how they can be targeted for conceptualizing successful cancer immunotherapy regimen.

At the Crossroads of the cGAS-cGAMP-STING Pathway and the DNA Damage Response: Implications for Cancer Progression and Treatment

The evolutionary conserved DNA-sensing cGAS-STING innate immunity pathway represents one of the most important cytosolic DNA-sensing systems that is activated in response to viral invasion and/or damage to the integrity of the nuclear envelope. The key outcome of this pathway is the production of interferon, which subsequently stimulates the transcription of hundreds of genes. In oncology, the situation is complex because this pathway may serve either anti- or pro-oncogenic roles, depending on context. The prevailing understanding is that when the innate immune response is activated by sensing cytosolic DNA, such as DNA released from ruptured micronuclei, it results in the production of interferon, which attracts cytotoxic cells to destroy tumors. However, in tumor cells that have adjusted to significant chromosomal instability, particularly in relapsed, treatment-resistant cancers, the cGAS-STING pathway often supports cancer progression, fostering the epithelial-to-mesenchymal transition (EMT). Here, we review this intricate pathway in terms of its association with cancer progression, giving special attention to pancreatic ductal adenocarcinoma and gliomas. As the development of new cGAS-STING-modulating small molecules and immunotherapies such as oncolytic viruses involves serious challenges, we highlight several recent fundamental discoveries, such as the proton-channeling function of STING. These discoveries may serve as guiding lights for potential pharmacological advancements.

Competition for H2A.Z underlies the developmental impacts of repetitive element de-repression

The histone variant H2A.Z is central to early embryonic development, determining transcriptional competency through chromatin regulation of gene promoters and enhancers. In addition to genic loci, we find that H2A.Z resides at a subset of evolutionarily young repetitive elements, including DNA transposons, long interspersed nuclear elements and long terminal repeats, during early zebrafish development. Moreover, increases in H2A.Z occur when repetitive elements become transcriptionally active. Acquisition of H2A.Z corresponds with a reduction in the levels of the repressive histone modification H3K9me3 and a moderate increase in chromatin accessibility. Notably, however, de-repression of repetitive elements also leads to a significant reduction in H2A.Z over non-repetitive genic loci. Genic loss of H2A.Z is accompanied by transcriptional silencing at adjacent coding sequences, but remarkably, these impacts are mitigated by augmentation of total H2A.Z protein via transgenic overexpression. Our study reveals that levels of H2A.Z protein determine embryonic sensitivity to de-repression of repetitive elements, that repetitive elements can function as a nuclear sink for epigenetic factors and that competition for H2A.Z greatly influences overall transcriptional output during development. These findings uncover general mechanisms in which counteractive biological processes underlie phenotypic outcomes.

Immunotoxicity and the mechanisms of aflatoxin B1-induced growth retardation in shrimp and alleviating effects of bile acids

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins prevalent in the environment and food chain, posing severe health risks to humans and animals. Bile acids are natural detergents synthesized from cholesterol and play a key role in the excretion of toxins in vertebrates. Here, pacific white shrimp (Litopenaeus vannamei) served as an animal model to examine the toxicity mechanisms of AFB1 and assess the potential alleviating effects of bile acids against AFB1. Our results revealed that AFB1 exposure significantly inhibited the growth performance and immune response of shrimp, accompanied by AFB1 accumulation and histological damage. Mechanistically, AFB1-induced DNA damage activated DNA repair mechanisms and induced the arrest of cell cycle via the ATR-cyclin B/cdc2 pathway. Additionally, AFB1 directly suppressed the immune response and growth performance of shrimp by inhibiting Toll and IMD pathways and the secretion of digestive enzymes. Notably, dietary bile acids significantly reduced AFB1 accumulation and alleviated AFB1-induced growth retardation and immunotoxicity in shrimp, and CCKAR, ATR, and Relish may be key mediators of the alleviating effects of bile acids. Our study provided new insights into the toxicity mechanisms of AFB1 in invertebrates and highlighted the potential of bile acids to alleviate AFB1 toxicity.

Natural-Product-Derived Adjunctive Treatments to Conventional Therapy and Their Immunoregulatory Activities in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an invasive and persistent subtype of breast cancer that is likely to be resistant to conventional treatments. The rise in immunotherapy has created new modalities to treat cancer, but due to high costs and unreliable efficacy, adjunctive and complementary treatments have sparked interest in enhancing the efficacy of currently available treatments. Natural products, which are bioactive compounds derived from natural sources, have historically been used to treat or ameliorate inflammatory diseases and symptoms. As TNBC patients have shown little to no response to immunotherapy, the potential of natural products as candidates for adjuvant immunotherapy is being explored, as well as their immunomodulatory effects on cancer. Due to the complexity of TNBC and the ever-changing tumor microenvironment, there are challenges in determining the feasibility of using natural products to enhance the efficacy or counteract the toxicity of conventional treatments. In view of technological advances in molecular docking, pharmaceutical networking, and new drug delivery systems, natural products show promise as potential candidates in adjunctive therapy. In this article, we summarize the mechanisms of action of selected natural-product-based bioactive compounds and analyze their roles and applications in combination treatments and immune regulation.

Inflammatory Cells Can Alter the Levels of H3K9ac and γH2AX in Dysplastic Cells and Favor Tumor Phenotype

Oral potentially malignant disorders (OPMD) are clinical presentations that carry an increased risk of cancer development. Currently, epithelial dysplasia grade is based on architectural and cytological epithelial changes and is used to predict the malignant transformation of these lesions. However, predicting which OPMD will progress to a malignant tumor is very challenging. Inflammatory infiltrates can favor cancer development, and recent studies suggest that this association with OPMD lesions may be related to the etiology and/or aggressive clinical behavior of these lesions. Epigenetic changes such as histone modifications may mediate chronic inflammation and also favor tumor cells in immune resistance and evasion. This study aimed to evaluate the relationship between histone acetylation (H3K9ac) and DNA damage in the context of dysplastic lesions with prominent chronic inflammation. Immunofluorescence of "low-risk" and "high-risk" OPMD lesions (n = 24) and inflammatory fibrous hyperplasia (n = 10) as the control group was performed to assess histone acetylation levels and DNA damage through the phosphorylation of H2AX (γH2AX). Cell co-culture assays with PBMCs and oral keratinocyte cell lines (NOK-SI, DOK, and SCC-25) were performed to assess proliferation, adhesion, migration, and epithelial-mesenchymal transition (EMT). Oral dysplastic lesions showed a hypoacetylation of H3K9 and low levels of γH2AX compared to control. The contact of dysplastic oral keratinocytes with PBMCs favored EMT and the loss of cell-cell adhesion. On the other hand, p27 levels increased and cyclin E decreased in DOK, indicating cell cycle arrest. We conclude that the presence of chronic inflammation associated to dysplastic lesions is capable of promoting epigenetic alterations, which in turn can favor the process of malignant transformation.

Effects of PFOS and cyclophosphamide exposure on immune homeostasis in mice

Perfluorooctane sulfonic acid (PFOS) is member of a class of molecules with fluorinated carbon chains known as polyfluoroalkyls. PFOS have been used to produce a variety of industry and comsumer uses. However, a significant concern is that it accumulates in the environment, including in animals and humans, and that it is a potential immunosuppressant. Here we analyze immune homeostasis in mice following chronic exposure to PFOS at levels up to those historically found in PFOS manufacturing workers. Mice were exposed to 0.15, 1.5, 15, or 50 µg /kg of PFOS for 28 days, after which, B cells, T cells, and granulocytes from the bone marrow, liver, spleen, lymph nodes, and thymus were evaluated. We find that at these exposures, there was no effect of PFOS on major T- or B-cell populations, macrophages, dendritic cells, basophils, mast cells, eosinophils, neutrophils, serum antibodies or select serum cytokines. By contrast, mice exposed the known immunosuppressant cyclophosphamide, which was given at 40 mg/kg for four days, exhibited depletion of several granulocyte, T- and B-cell populations of the thymus, bone marrow, and spleen, as well as circulating IgM and IgE antibodies. These data indicate that exposures of up to 50 µg /kg of PFOS for 28 days does not affect immune homeostasis in mice.

Unobvious Neutrophil Extracellular Traps Signification in the Course of Oral Squamous Cell Carcinoma: Current Understanding and Future Perspectives

Background: The current standards of treatment for oral squamous cell carcinoma (OSCC) include surgery, radiotherapy, and chemotherapy. In recent years, research on the effectiveness of immunotherapy in the treatment of OSCC has also been conducted.Purpose: Studies indicate that nonspecific immune mechanisms involved in the course of the anticancer response also need to be taken into account.Research Design: This review summarizes the results of our research on the active participation of neutrophils, which are previously underestimated, in the antitumor response in the course of OSCC, taking into account the ability of these cells to generate neutrophil extracellular traps (NETs).Results: We proved that the formation of NETs accompanies not only inflammatory changes but also the neoplastic process and that lipopolysaccharide (LPS) or interleukin 17 (IL-17) plays a critical role in inducing the formation of NETs during the OSCC. The greatest achievement of our published findings was the demonstration of the formation and release of NETs from neutrophils cocultured with tumor cells, as well as after stimulation with supernatant from the SCC culture with a PI3K-independent Akt kinase activation mechanism. Moreover, the pioneering achievement of our studies was the localization of NET structures in the tumor tissue, as well as the observation of high concentrations of NET markers in the serum of OSCC patients with low concentrations in the saliva, indicating the differences in the course of immune response between the periphery and the local reactions.Conclusions: The data presented here provide surprising but important information on the role of NETs in the course of OSCC, thus pointing to a promising new direction in the development of management strategies for early noninvasive diagnosis and monitoring of the disease course, and perhaps immunotherapy. Furthermore, this review raises further questions and elaborates on the process of NETosis in cancer.

Phase separation drives the formation of biomolecular condensates in the immune system

When the external conditions change, such as the temperature or the pressure, the multi-component system sometimes separates into several phases with different components and structures, which is called phase separation. Increasing studies have shown that cells condense related biomolecules into independent compartments in order to carry out orderly and efficient biological reactions with the help of phase separation. Biomolecular condensates formed by phase separation play a significant role in a variety of cellular processes, including the control of signal transduction, the regulation of gene expression, and the stress response. In recent years, many phase separation events have been discovered in the immune response process. In this review, we provided a comprehensive and detailed overview of the role and mechanism of phase separation in the innate and adaptive immune responses, which will help the readers to appreciate the advance and importance of this field.

Metabolic communication in the tumour-immune microenvironment

The metabolically hostile tumour microenvironment imposes barriers to tumour-infiltrating immune cells and impedes durable clinical remission following immunotherapy. Metabolic communication between cancer cells and their neighbouring immune cells could determine the amplitude and type of immune responses, highlighting a potential involvement of metabolic crosstalk in immune surveillance and escape. In this Review, we explore tumour-immune metabolic crosstalk and discuss potential nutrient-limiting strategies that favour anti-tumour immune responses.

DNA damage, inflammation and aging: Insights from mice

Persistent DNA lesions build up with aging triggering inflammation, the body’s first line of immune defense strategy against foreign pathogens and irritants. Once established, DNA damage-driven inflammation takes on a momentum of its own, due to the amplification and feedback loops of the immune system leading to cellular malfunction, tissue degenerative changes and metabolic complications. Here, we discuss the use of murine models with inborn defects in genome maintenance and the DNA damage response for understanding how irreparable DNA lesions are functionally linked to innate immune signaling highlighting their relevance for developing novel therapeutic strategies against the premature onset of aging-associated diseases.

Upregulation of NKG2D ligands impairs hematopoietic stem cell function in Fanconi anemia

Fanconi anemia (FA) is the most prevalent inherited bone marrow failure (BMF) syndrome. Nevertheless, the pathophysiological mechanisms of BMF in FA have not been fully elucidated. Since FA cells are defective in DNA repair, we hypothesized that FA hematopoietic stem and progenitor cells (HSPCs) might express DNA damage–associated stress molecules such as natural killer group 2 member D ligands (NKG2D-Ls). These ligands could then interact with the activating NKG2D receptor expressed in cytotoxic NK or CD8⁺ T cells, which may result in progressive HSPC depletion. Our results indeed demonstrated upregulated levels of NKG2D-Ls in cultured FA fibroblasts and T cells, and these levels were further exacerbated by mitomycin C or formaldehyde. Notably, a high proportion of BM CD34⁺ HSPCs from patients with FA also expressed increased levels of NKG2D-Ls, which correlated inversely with the percentage of CD34⁺ cells in BM. Remarkably, the reduced clonogenic potential characteristic of FA HSPCs was improved by blocking NKG2D–NKG2D-L interactions. Moreover, the in vivo blockage of these interactions in a BMF FA mouse model ameliorated the anemia in these animals. Our study demonstrates the involvement of NKG2D–NKG2D-L interactions in FA HSPC functionality, suggesting an unexpected role of the immune system in the progressive BMF that is characteristic of FA.

CD3+CD4-CD8- (Double-Negative) T Cells in Inflammation, Immune Disorders and Cancer

The crucial role of CD4⁺ and CD8⁺ T cells in shaping and controlling immune responses during immune disease and cancer development has been well established and used to achieve marked clinical benefits. CD3⁺CD4^-CD8^- double-negative (DN) T cells, although constituting a rare subset of peripheral T cells, are gaining interest for their roles in inflammation, immune disease and cancer. Herein, we comprehensively review the origin, distribution and functions of this unique T cell subgroup. First, we focused on characterizing multifunctional DN T cells in various immune responses. DN regulatory T cells have the capacity to prevent graft-versus-host disease and have therapeutic value for autoimmune disease. T helper-like DN T cells protect against or promote inflammation and virus infection depending on the specific settings and promote certain autoimmune disease. Notably, we clarified the role of DN tumor-infiltrating lymphocytes and outlined the potential for malignant proliferation of DN T cells. Finally, we reviewed the recent advances in the applications of DN T cell-based therapy for cancer. In conclusion, a better understanding of the heterogeneity and functions of DN T cells may help to develop DN T cells as a potential therapeutic tool for inflammation, immune disorders and cancer.

Natural Killer Cells: the Missing Link in Effective Treatment for High-Grade Serous Ovarian Carcinoma

OPINION STATEMENT

Ovarian cancer (OC), especially high-grade serous cancer (HGSC), is a highly heterogeneous malignancy with limited options for curative treatment and a high frequency of relapse. Interactions between OC and the immune system may permit immunoediting and immune escape, and current standard of care therapies can influence immune cell infiltration and function within the tumor microenvironment. Natural killer (NK) cells are involved in cancer immunosurveillance and immunoediting and can be activated by therapy, but deliberate approaches to maximize NK cell reactivity for treatment of HGSC are in their infancy. NK cells may be the ideal target for immunotherapy of HGSC. The diverse functions of NK cells, and their established roles in immunosurveillance, make them attractive candidates for more precise and effective HGSC treatment. NK cells' functional capabilities differ because of variation in receptor expression and genetics, with meaningful impacts on their anticancer activity. Studying HGSC:NK cell interactions will define the features that predict the best outcomes for patients with the disease, but the highly diverse nature of HGSC will likely require combination therapies or approaches to simultaneously target multiple, co-existing features of the tumor to avoid tumor escape and relapse. We expect that the ideal therapy will enable NK cell infiltration and activity, reverse immunosuppression within the tumor microenvironment, and enable effector functions against the diverse subpopulations that comprise HGSC.

Role of Hypoxia in the Interferon Response

In solid tumors, as the tumor grows and the disease progresses, hypoxic regions are often generated, but in contrast to most normal cells which cannot survive under these conditions, tumour cells adapt to hypoxia by HIF-driven mechanisms. Hypoxia can further promote cancer development by generating an immunosuppressive environment within the tumour mass, which allows tumour cells to escape the immune system recognition. This is achieved by recruiting immunosuppressive cells and by upregulating molecules which block immune cell activation. Hypoxia can also confer resistance to antitumor therapies by inducing the expression of membrane proteins that increase drug efflux or by inhibiting the apoptosis of treated cells. In addition, tumor cells require an active interferon (IFN) signalling pathway for the success of many anticancer therapies, such as radiotherapy or chemotherapy. Therefore, hypoxic effects on this pathway needs to be addressed for a successful treatment.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review (Part 6): Correlation of PD-L1 Expression with the Status of Mismatch Repair System, BRCA, PTEN, and Other Genes

Pembrolizumab (anti-PD-1) is allowed in selected metastatic castration-resistant prostate cancer (PC) patients showing microsatellite instability/mismatch repair system deficiency (MSI-H/dMMR). BRCA1/2 loss-of-function is linked to hereditary PCs and homologous recombination DNA-repair system deficiency: poly-ADP-ribose-polymerase inhibitors can be administered to BRCA-mutated PC patients. Recently, docetaxel-refractory metastatic castration-resistant PC patients with BRCA1/2 or ATM somatic mutations had higher response rates to pembrolizumab. PTEN regulates cell cycle/proliferation/apoptosis through pathways including the AKT/mTOR, which upregulates PD-L1 expression in PC. Our systematic literature review (PRISMA guidelines) investigated the potential correlations between PD-L1 and MMR/MSI/BRCA/PTEN statuses in PC, discussing few other relevant genes. Excluding selection biases, 74/677 (11%) PCs showed dMMR/MSI; 8/67 (12%) of dMMR/MSI cases were PD-L1+. dMMR-PCs included ductal (3%) and acinar (14%) PCs (all cases tested for MSI were acinar-PCs). In total, 15/39 (39%) PCs harbored BRCA1/2 aberrations: limited data are available for PD-L1 expression in these patients. 13/137 (10%) PTEN- PCs were PD-L1+; 10/29 (35%) PD-L1+ PCs showed PTEN negativity. SPOP mutations may increase PD-L1 levels, while the potential correlation between PD-L1 and ERG expression in PC should be clarified. Further research should verify how the efficacy of PD-1 inhibitors in metastatic castration-resistant PCs is related to dMMR/MSI, DNA-damage repair genes defects, or PD-L1 expression.

BIRC2-BIRC3 amplification: a potentially druggable feature of a subset of head and neck cancers in patients with Fanconi anemia

Head-and-neck squamous cell carcinomas (HNSCCs) are relatively common in patients with Fanconi anemia (FA), a hereditary chromosomal instability disorder. Standard chemo-radiation therapy is not tolerated in FA due to an overall somatic hypersensitivity to such treatment. The question is how to find a suitable alternative treatment. We used whole-exome and whole genome mRNA sequencing to identify major genomic and transcriptomic events associated with FA-HNSCC. CRISPR-engineered FA-knockout models were used to validate a number of top hits that were likely to be druggable. We identified deletion of 18q21.2 and amplification of 11q22.2 as prevailing copy-number alterations in FA HNSCCs, the latter of which was associated with strong overexpression of the cancer-related genes YAP1, BIRC2, BIRC3 (at 11q22.1-2). We then found the drug AZD5582, a known small molecule inhibitor of BIRC2-3, to selectively kill FA tumor cells that overexpressed BIRC2-3. This occurred at drug concentrations that did not affect the viability of untransformed FA cells. Our data indicate that 11q22.2 amplifications are relatively common oncogenic events in FA-HNSCCs, as holds for non FA-HNSCC. Therefore, chemotherapeutic inhibition of overexpressed BIRC2-3 may provide the basis for an approach to develop a clinically realistic treatment of FA-HNSCCs that carry 11q22.2 amplifications.

Probiotics in Counteracting the Role of Neutrophils in Cancer Metastasis

Neutrophils are known for their role geared towards pathogen clearance by different mechanisms that they initiate, primarily by the release of neutrophil extracellular traps (NETs). However, their immune-surveillance capacity accompanied with plasticity in existing as interchangeable subsets, discovered recently, has revealed their property to contribute to complex cancer pathologies including tumor initiation, growth, angiogenesis and metastasis. Although there is a growing body of evidence suggesting a critical balance between the protumoral and antitumoral neutrophil phenotypes, an in-depth signaling pathway analysis would aid in determination of anticipatory, diagnostic and therapeutic targets. This review presents a comprehensive overview of the potential pathways involved in neutrophil-triggered cancer metastasis and introduces the influence of the microbial load and avenues for probiotic intervention.

Review of Standardized Incidence Ratios (SIR) of non-lymphoid de novo malignancies after liver transplantation: Structured analysis of global differences

INTRODUCTION

De Novo malignancy after liver transplantation (LTx) is the second most common cause of death in adult LTx recipients. The current report identifies differences in Standardized Incidence Ratios (SIR) for various non-lymphoid de novo malignancies by comparing and analyzing post LTx SIR for non-lymphoid de novo malignancies.

MATERIAL AND METHODS

A thorough search of PubMed and Web of Science databases was conducted; 25 publications describing de novo malignancies post-LTx with SIR were identified.

RESULTS

Overall SIR varied from 1.4 to 11.6 (median 2.4). Oropharyngeal/larynx (OPL), lung, colo-rectal, and kidney malignancies were more prevalent with higher SIR (median = 4.4, 1.9, 2.67, 2.5, respectively). Breast and prostate malignancies were also more prevalent with lower SIR (median = 0.9, 1.0, respectively). Pancreatic, central nervous system (CNS), melanoma, rare cancers and Kaposi's sarcoma were less prevalent (except in Italy and Sweden) but had much higher SIR (median = 2.6, 2.4, 2.02, 22.5 and 53.6, respectively). The overall higher SIR values are related to the age of the recipient, length of follow-up, the grouping of different organ systems, inclusion or exclusion of epidermal non-malacotic skin cancers, lymphoid malignancy, and occurrence of rare malignancies including Kaposi's sarcoma.

CONCLUSION

OPL, lung, gastrointestinal, kidney, and bladder malignancies were more prevalent with higher SIR. Breast and prostate cancers were more prevalent with lower SIR. Pancreatic, CNS, melanoma, rare cancers and Kaposi's sarcoma were less prevalent with higher SIR. Age of the recipients, length of follow-up, and rare cancer types influence overall SIR values with some global differences.

Evaluation of an RNAseq-Based Immunogenomic Liquid Biopsy Approach in Early-Stage Prostate Cancer

The primary objective of this study is to detect biomarkers and develop models that enable the identification of clinically significant prostate cancer and to understand the biologic implications of the genes involved. Peripheral blood samples (1018 patients) were split chronologically into independent training (n = 713) and validation (n = 305) sets. Whole transcriptome RNA sequencing was performed on isolated phagocytic CD14+ and non-phagocytic CD2+ cells and their gene expression levels were used to develop predictive models that correlate to adverse pathologic features. The immune-transcriptomic model with the highest performance for predicting adverse pathology, based on a subtraction of the log-transformed expression signals of the two cell types, displayed an area under the curve (AUC) of the receiver operating characteristic of 0.70. The addition of biomarkers in combination with traditional clinical risk factors (age, serum prostate-specific antigen (PSA), PSA density, race, digital rectal examination (DRE), and family history) enhanced the AUC to 0.91 and 0.83 for the training and validation sets, respectively. The markers identified by this approach uncovered specific pathway associations relevant to (prostate) cancer biology. Increased phagocytic activity in conjunction with cancer-associated (mis-)regulation is also represented by these markers. Differential gene expression of circulating immune cells gives insight into the cellular immune response to early tumor development and immune surveillance.

DNA damage repair: historical perspectives, mechanistic pathways and clinical translation for targeted cancer therapy

Genomic instability is the hallmark of various cancers with the increasing accumulation of DNA damage. The application of radiotherapy and chemotherapy in cancer treatment is typically based on this property of cancers. However, the adverse effects including normal tissues injury are also accompanied by the radiotherapy and chemotherapy. Targeted cancer therapy has the potential to suppress cancer cells' DNA damage response through tailoring therapy to cancer patients lacking specific DNA damage response functions. Obviously, understanding the broader role of DNA damage repair in cancers has became a basic and attractive strategy for targeted cancer therapy, in particular, raising novel hypothesis or theory in this field on the basis of previous scientists' findings would be important for future promising druggable emerging targets. In this review, we first illustrate the timeline steps for the understanding the roles of DNA damage repair in the promotion of cancer and cancer therapy developed, then we summarize the mechanisms regarding DNA damage repair associated with targeted cancer therapy, highlighting the specific proteins behind targeting DNA damage repair that initiate functioning abnormally duo to extrinsic harm by environmental DNA damage factors, also, the DNA damage baseline drift leads to the harmful intrinsic targeted cancer therapy. In addition, clinical therapeutic drugs for DNA damage and repair including therapeutic effects, as well as the strategy and scheme of relative clinical trials were intensive discussed. Based on this background, we suggest two hypotheses, namely "environmental gear selection" to describe DNA damage repair pathway evolution, and "DNA damage baseline drift", which may play a magnified role in mediating repair during cancer treatment. This two new hypothesis would shed new light on targeted cancer therapy, provide a much better or more comprehensive holistic view and also promote the development of new research direction and new overcoming strategies for patients.

Targeting the replication stress response through synthetic lethal strategies in cancer medicine

The replication stress response (RSR) involves a downstream kinase cascade comprising ataxia telangiectasia-mutated (ATM), ATM and rad3-related (ATR), checkpoint kinases 1 and 2 (CHK1/2), and WEE1-like protein kinase (WEE1), which cooperate to arrest the cell cycle, protect stalled forks, and allow time for replication fork repair. In the presence of elevated replicative stress, cancers are increasingly dependent on RSR to maintain genomic integrity. An increasing number of drug candidates targeting key RSR nodes, as monotherapy through synthetic lethality, or through rational combinations with immune checkpoint inhibitors and targeted therapies, are demonstrating promising efficacy in early phase trials. RSR targeting is also showing potential in reversing PARP inhibitor resistance, an important area of unmet clinical need. In this review, we introduce the concept of targeting the RSR, detail the current landscape of monotherapy and combination strategies, and discuss emerging therapeutic approaches, such as targeting Polθ.

The relationship between defects in DNA repair genes and autoinflammatory diseases

Tissue inflammation and damage with the abnormal and overactivation of innate immune system results with the development of a hereditary disease group of autoinflammatory diseases. Multiple numbers of DNA damage develop with the continuous exposure to endogenous and exogenous genotoxic effects, and these damages are repaired through the DNA damage response governed by the genes involved in the DNA repair mechanisms, and proteins of these genes. Studies showed that DNA damage might trigger the innate immune response through nuclear DNA accumulation in the cytoplasm, and through chronic DNA damage response which signals itself and/or by micronucleus. The aim of the present review is to identify the effect of mutation that occurred in DNA repair genes on development of DNA damage response and autoinflammatory diseases.

A Molecular Interaction Map of Klebsiella pneumoniae and Its Human Host Reveals Potential Mechanisms of Host Cell Subversion

Klebsiella pneumoniae is a leading cause of pneumonia and septicemia across the world. The rapid emergence of multidrug-resistant K. pneumoniae strains necessitates the discovery of effective drugs against this notorious pathogen. However, there is a dearth of knowledge on the mechanisms by which this deadly pathogen subverts host cellular machinery. To fill this knowledge gap, our study attempts to identify the potential mechanisms of host cell subversion by building a K. pneumoniae-human interactome based on rigorous computational methodology. The putative host targets inferred from the predicted interactome were found to be functionally enriched in the host's immune surveillance system and allied functions like apoptosis, hypoxia, etc. A multifunctionality-based scoring system revealed P53 as the most multifunctional protein among host targets accompanied by HIF1A and STAT1. Moreover, mining of host protein-protein interaction (PPI) network revealed that host targets interact among themselves to form a network (TTPPI), where P53 and CDC5L occupy a central position. The TTPPI is composed of several inter complex interactions which indicate that K. pneumoniae might disrupt functional coordination between these protein complexes through targeting of P53 and CDC5L. Furthermore, we identified four pivotal K. pneumoniae-targeted transcription factors (TTFs) that are part of TTPPI and are involved in generating host's transcriptional response to K. pneumoniae-mediated sepsis. In a nutshell, our study identifies some of the pivotal molecular targets of K. pneumoniae which primarily correlate to the physiological response of host during K. pneumoniae-mediated sepsis.

Effect of 4,5-diazafluorene derivative on γδ T cell-mediated cytotoxicity against renal cell carcinoma

AIMS

This study aimed to investigate the effect of previously synthesized 4,5-diazafluorene derivative (14c) on γδ T cell-mediated cytotoxicity against renal cell carcinoma (RCC).

MATERIALS AND METHODS

A real-time cell analyzer monitored cell proliferation, and Cell Counting Kit-8 determined cell viability. A reverse transcription-polymerase chain reaction analyzed gene expression, and protein expression was determined by cellular immunofluorescence analysis and Western blot.

KEY FINDINGS

The compound 14c induced the expression of immunomodulatory molecules, such as natural killer group 2, member D ligands (NKG2DLs), fibroblast-associated (Fas) death receptor, and tumor necrosis factor-related apoptosis-inducing ligand receptors (TRAILRs) in RCC. In addition, 14c induced DNA damage responses in RCC. Blocking DNA damage by KU-55933 reduced the effect of γδ T cells on 14c-treated RCC, suggesting that DNA damage responses were involved in the augmentation of γδ T cell-mediated cytotoxicity. Treating 786-O cells with a nitrogen-containing bisphosphonate prodrug further enhanced the anti-tumor effect of γδ T cell plus 14c combination treatment.

SIGNIFICANCE

The present evidence indicates that 14c induced DNA damage responses in RCC and augmented γδ T cell-mediated cytotoxicity primarily through NKG2D/NKG2DLs pathways, suggesting potential cancer immunotherapy for harnessing γδ T cells and small compounds that induce DNA damage responses.

Liposomal doxorubicin attenuates cardiotoxicity via induction of interferon-related DNA damage resistance

AIMS

The clinical application of doxorubicin (DOX) is severely compromised by its cardiotoxic effects, which limit the therapeutic index and the cumulative dose. Liposomal encapsulation of DOX (Myocet®) provides a certain protective effect against cardiotoxicity by reducing myocardial drug accumulation. We aimed to evaluate transcriptomic responses to anthracyclines with different cardiotoxicity profiles in a translational large animal model for identifying potential alleviation strategies.

METHODS AND RESULTS

We treated domestic pigs with either DOX, epirubicin (EPI), or liposomal DOX and compared the cardiac, laboratory, and haemodynamic effects with saline-treated animals. Cardiotoxicity was encountered in all groups, reflected by an increase of plasma markers N-terminal pro-brain-natriuretic peptide and Troponin I and an impact on body weight. High morbidity of EPI-treated animals impeded further evaluation. Cardiac magnetic resonance imaging with gadolinium late enhancement and transthoracic echocardiography showed stronger reduction of the left and right ventricular systolic function and stronger myocardial fibrosis in DOX-treated animals than in those treated with the liposomal formulation. Gene expression profiles of the left and right ventricles were analysed by RNA-sequencing and validated by qPCR. Interferon-stimulated genes (ISGs), linked to DNA damage repair and cell survival, were downregulated by DOX, but upregulated by liposomal DOX in both the left and right ventricle. The expression of cardioprotective translocator protein (TSPO) was inhibited by DOX, but not its liposomal formulation. Cardiac fibrosis with activation of collagen was found in all treatment groups.

CONCLUSIONS

All anthracycline-derivatives resulted in transcriptional activation of collagen synthesis and processing. Liposomal packaging of DOX-induced ISGs in association with lower cardiotoxicity, which is of high clinical importance in anticancer treatment. Our study identified potential mechanisms for rational development of strategies to mitigate anthracycline-induced cardiomyopathy.

DNA Damage Response and Immune Defense

DNA damage is the cause of numerous human pathologies including cancer, premature aging, and chronic inflammatory conditions. The DNA damage response (DDR), in turn, coordinates DNA damage checkpoint activation and promotes the removal of DNA lesions. In recent years, several studies have shown how the DDR and the immune system are tightly connected, revealing an important crosstalk between the two of them. This interesting interplay has opened up new perspectives in clinical studies for immunological diseases as well as for cancer treatment. In this review, we provide an overview, from cellular to molecular pathways, on how DDR and the immune system communicate and share the crucial commitment of maintaining the genomic fitness.

Consensus transcriptional regulatory networks of coronavirus-infected human cells

Establishing consensus around the transcriptional interface between coronavirus (CoV) infection and human cellular signaling pathways can catalyze the development of novel anti-CoV therapeutics. Here, we used publicly archived transcriptomic datasets to compute consensus regulatory signatures, or consensomes, that rank human genes based on their rates of differential expression in MERS-CoV (MERS), SARS-CoV-1 (SARS1) and SARS-CoV-2 (SARS2)-infected cells. Validating the CoV consensomes, we show that high confidence transcriptional targets (HCTs) of MERS, SARS1 and SARS2 infection intersect with HCTs of signaling pathway nodes with known roles in CoV infection. Among a series of novel use cases, we gather evidence for hypotheses that SARS2 infection efficiently represses E2F family HCTs encoding key drivers of DNA replication and the cell cycle; that progesterone receptor signaling antagonizes SARS2-induced inflammatory signaling in the airway epithelium; and that SARS2 HCTs are enriched for genes involved in epithelial to mesenchymal transition. The CoV infection consensomes and HCT intersection analyses are freely accessible through the Signaling Pathways Project knowledgebase, and as Cytoscape-style networks in the Network Data Exchange repository.

Olaparib combined with immunotherapy for treating a patient with liver cancer carrying BRCA2 germline mutation: A case report

RATIONALE

Immunotherapy and targeted therapy have attracted widespread attention in current clinical research, which could be considered as a good therapeutic option for treatment of refractory liver cancer.

PATIENT CONCERNS

The patient was a 37-year-old man with hepatitis B virus (HBV) infection. He was presented with hepatalgia and discomfort.

DIAGNOSIS

The computed tomography showed multiple intrahepatic masses, indicating primary liver cancer with multiple intrahepatic metastases.

INTERVENTIONS

After failed transarterial chemoembolization therapy, he was initially treated with immunotherapy pembrolizumab plus angiogenesis inhibitor lenvatinib, and after 3 months of treatment, the condition improved. However, the disease subsequently progressed. The next-generation sequencing identified a BRCA2 germline mutation in this patient. A poly (ADP-ribose) polymerase inhibitor, olaparib, plus nivolumab therapy was started and achieved stable disease.

OUTCOMES

The patient achieved stable disease and improvement in hepatalgia for 3 months after the combination treatment of Olaparib and nivolumab.

CONCLUSION

We identified a BRCA2 germline mutation in a patient with liver cancer. Our findings could offer an alternative management for patients with liver cancer harboring germline BRCA2 mutation.

Radiation Therapy and the In Situ Vaccination Approach

During the past century, from the advent of preclinical modeling to the establishment of clinical trials, the hypothesis that host defenses regulate tumor growth (posited and refined by leaders in the field of cancer immunity) has become accepted as a scientific pillar in oncology. Since the turn of the millennium, a search has been under way for the best therapeutic approach to reprogram the immune system to recognize tumor cells that have undergone "immune escape." This quest has led some to question conventional scientific views of tumor cell kill, including the role of host immunity in patients treated with radiation therapy. In the last two decades, evidence has accumulated that radiation therapy can effectively convert a potentially lethal cancer into an in situ personalized vaccine. Herein, we review the underlying mechanisms and maneuvers responsible for in situ vaccine production.

A Review About Pembrolizumab in First-Line Treatment of Advanced NSCLC: Focus on KEYNOTE Studies

 Lung cancer is currently the malignant tumor with the highest incidence and mortality in the world, while non-small cell lung cancer (NSCLC) is the most common pathological type of lung caner. In the past few decades, the only treatment options available for advanced NSCLC patients have been targeted therapy or chemotherapy, but these therapies are inevitably tolerated by tumors.  The discovery of immune checkpints that mediate the immune escape of tumor cells have been promoting a series of immune checkpoint inhibitors to be used in cancer treatment and achieved great results. Among them, pembrolizumab is currently the only PD-1 inhibitor approved for first-line treatment of NSCLC, whether it is monotherapy or combination therapy, for creditable performance in KEYNOTE studies. In this review, we systematically integrate the latest series of clinical trial results, pharmacological mechanisms, adverse events (AEs) and predictive biomarkers in the first-line treatment of NSCLC. We hope pembrolizumab could become a better choice for more clinicians and benefit more patients with advanced NSCLC.

Consensus transcriptional regulatory networks of coronavirus-infected human cells

Establishing consensus around the transcriptional interface between coronavirus (CoV) infection and human cellular signaling pathways can catalyze the development of novel anti-CoV therapeutics. Here, we used publicly archived transcriptomic datasets to compute consensus regulatory signatures, or consensomes, that rank human genes based on their rates of differential expression in MERS-CoV (MERS), SARS-CoV-1 (SARS1) and SARS-CoV-2 (SARS2)-infected cells. Validating the CoV consensomes, we show that high confidence transcriptional targets (HCTs) of CoV infection intersect with HCTs of signaling pathway nodes with known roles in CoV infection. Among a series of novel use cases, we gather evidence for hypotheses that SARS2 infection efficiently represses E2F family target genes encoding key drivers of DNA replication and the cell cycle; that progesterone receptor signaling antagonizes SARS2-induced inflammatory signaling in the airway epithelium; and that SARS2 HCTs are enriched for genes involved in epithelial to mesenchymal transition. The CoV infection consensomes and HCT intersection analyses are freely accessible through the Signaling Pathways Project knowledgebase, and as Cytoscape-style networks in the Network Data Exchange repository.

Antibody targeting tumor-derived soluble NKG2D ligand sMIC reprograms NK cell homeostatic survival and function and enhances melanoma response to PDL1 blockade therapy

BACKGROUND

Melanoma patients who have detectable serum soluble NKG2D ligands either at the baseline or post-treatment of PD1/PDL1 blockade exhibit poor overall survival. Among families of soluble human NKG2D ligands, the soluble human MHC I chain-related molecule (sMIC) was found to be elevated in melanoma patients and mostly associated with poor response to PD1/PDL1 blockade therapy.

METHODS

In this study, we aim to investigate whether co-targeting tumor-released sMIC enhances the therapeutic outcome of PD1/PDL1 blockade therapy for melanoma. We implanted sMIC-expressing B16F10 melanoma tumors into syngeneic host and evaluated therapeutic efficacy of anti-sMIC antibody and anti-PDL1 antibody combination therapy in comparison with monotherapy. We analyzed associated effector mechanism. We also assessed sMIC/MIC prevalence in metastatic human melanoma tumors.

RESULTS

We found that the combination therapy of the anti-PDL1 antibody with an antibody targeting sMIC significantly improved animal survival as compared to monotherapies and that the effect of combination therapy depends significantly on NK cells. We show that combination therapy significantly increased IL-2Rα (CD25) on NK cells which sensitizes NK cells to low dose IL-2 for survival. We demonstrate that sMIC negatively reprograms gene expression related to NK cell homeostatic survival and proliferation and that antibody clearing sMIC reverses the effect of sMIC and reprograms NK cell for survival. We further show that sMIC/MIC is abundantly present in metastatic human melanoma tumors.

CONCLUSIONS

Our findings provide a pre-clinical proof-of-concept and a new mechanistic understanding to underscore the significance of antibody targeting sMIC to improve therapeutic efficacy of anti-PD1/PDL1 antibody for MIC/sMIC⁺ metastatic melanoma patients.

Replication Stress, DNA Damage, Inflammatory Cytokines and Innate Immune Response

Complete and accurate DNA replication is essential to genome stability maintenance during cellular division. However, cells are routinely challenged by endogenous as well as exogenous agents that threaten DNA stability. DNA breaks and the activation of the DNA damage response (DDR) arising from endogenous replication stress have been observed at pre- or early stages of oncogenesis and senescence. Proper detection and signalling of DNA damage are essential for the autonomous cellular response in which the DDR regulates cell cycle progression and controls the repair machinery. In addition to this autonomous cellular response, replicative stress changes the cellular microenvironment, activating the innate immune response that enables the organism to protect itself against the proliferation of damaged cells. Thereby, the recent descriptions of the mechanisms of the pro-inflammatory response activation after replication stress, DNA damage and DDR defects constitute important conceptual novelties. Here, we review the links of replication, DNA damage and DDR defects to innate immunity activation by pro-inflammatory paracrine effects, highlighting the implications for human syndromes and immunotherapies.

Integrating tumor hypoxic stress in novel and more adaptable strategies for cancer immunotherapy

Immunotherapy is poised to become an increasingly utilized therapy in the treatment of cancer. However, several abnormalities in the tumor microenvironment (TME) that can thwart the efficacy of immunotherapies have been established. Microenvironmental hypoxia is a determining factor in shaping aggressiveness, metastatic potential and treatment resistance of solid tumors. The characterization of this phenomenon could prove beneficial for determining a patient's treatment path and for the introduction of novel targetable factors that can enhance therapeutic outcome. Indeed, the ablation of hypoxia has the potential to sensitize tumors to immunotherapy by metabolically remodeling their microenvironment. In this review, we discuss the intrinsic contributions of hypoxia to cellular plasticity, heterogeneity, stemness and genetic instability in the context of immune escape. In addition, we will shed light on how managing hypoxia can ameliorate response to immunotherapy and how integrating hypoxia gene signatures could play a role in this pursuit.

The CD26/DPP4-inhibitor vildagliptin suppresses lung cancer growth via macrophage-mediated NK cell activity

CD26/dipeptidyl peptidase 4 (DPP4) is a transmembrane protein which is expressed by various malignant cells. We found that the expression of CD26/DPP4 was significantly higher in lung adenocarcinoma samples in our own patient cohort compared to normal lung tissue. We therefore hypothesize that the inhibition of CD26/DPP4 can potentially suppress lung cancer growth. The CD26/DPP4 inhibitor vildagliptin was employed on Lewis Lung Carcinoma (LLC) cell line and a human lung adenocarcinoma (H460) cell line. Two weeks after subcutaneous injection of tumor cells into C57BL/6 and CD1/nude mice, the size of LLC and H460 tumors was significantly reduced by vildagliptin. Immunohistochemically, the number of macrophages (F4/80+) and NK cells (NKp46+) was significantly increased in vildagliptin-treated tumor samples. Mechanistically, we found in vitro that lung cancer cell lines expressed increased levels of surfactant protein upon vildagliptin treatment thereby promoting the pro-inflammatory activity of macrophages. By the depletion of macrophages with clodronate and by using NK cell deficient (IL-15-/-) mice, tumors reversed to the size of controls, suggesting that indeed macrophages and NK cells were responsible for the observed tumor-suppressing effect upon vildagliptin treatment. FACS analysis showed tumor-infiltrating NK cells to express tumor necrosis-related apoptosis-inducing ligand (TRAIL) which induced the intra-cellular stress marker γH2AX. Accordingly, we found upregulated γH2AX in vildagliptin-treated tumors and TRAIL-treated cell lines. Moreover, the effect of vildagliptin-mediated enhanced NK cell cytotoxicity could be reversed by antagonizing the TRAIL receptor. Our data provide evidence that the CD26/DPP4-inhibitor vildagliptin reduces lung cancer growth. We could demonstrate that this effect is exerted by surfactant-activated macrophages and NK cells that act against the tumor via TRAIL-mediated cytotoxicity.

Antigenotoxic Effects of Biochaga and Dihydroquercetin (Taxifolin) on H2O2-Induced DNA Damage in Human Whole Blood Cells

The health benefits of natural products have long been recognized. Consumption of dietary compounds such as supplements provides an alternative source of natural products to those obtained from the diet. There is a growing concern regarding the possible side effects of using different food supplements simultaneously, since their possible interactions are less known. For the first time, we have tested genotoxic and antigenotoxic effects of Biochaga, in combination with dihydroquercetin. No genotoxic effect on whole blood cells was observed within individual treatment of Biochaga (250 μg/mL, 500 μg/mL and 1000 μg/mL) and dihydroquercetin (100 μg/mL, 250 μg/mL and 500 μg/mL), nor in combination. Afterwards, antigenotoxic potency of both supplements against hydrogen peroxide- (H₂O₂-) induced DNA damage to whole blood cells (WBC) was assessed, using the comet assay. Biochaga and dihydroquercetin displayed a strong potential to attenuate H₂O₂-induced damage on DNA in cells at all tested concentrations, with a statistical significance (p < 0.05), whereas Biochaga at the dose of 500 μg/mL in combination with dihydroquercetin 500 μg/mL was most prominent. Biochaga in combination with dihydroquercetin is able to protect genomic material from oxidative damage induced by hydrogen peroxide in vitro.

ARID1A Mutations Are Associated with Increased Immune Activity in Gastrointestinal Cancer

Because traditional treatment strategies for advanced gastrointestinal (GI) cancers often have a limited therapeutic effect, immunotherapy could be a viable approach for the therapy of advanced GI cancers, considering the recent success of immunotherapy in treating various refractory malignancies, including the DNA mismatch repair-deficient GI cancers. However, only a subset of cancer patients currently respond to immunotherapy. Thus, it is important to identify useful biomarkers for predicting cancer immunotherapy response. The tumor suppressor gene ARID1A has a high mutation rate in GI cancers and its deficiency is correlated with the microsatellite instability (MSI) genomic feature of cancer. We investigated the correlation between ARID1A mutations and tumor immunity using three GI cancer genomics datasets by the bioinformatic approach, and found that diverse antitumor immune signatures were more highly enriched in ARID1A-mutated GI cancers than in ARID1A-wildtype GI cancers. The elevated immune activity in ARID1A-mutated GI cancers was associated with the higher tumor mutation burden and lower tumor aneuploidy level, as well as a higher proportion of MSI cancers in this GI cancer subtype. Moreover, we found that ARID1A-mutated GI cancers more highly expressed PD-L1 than ARID1A-wildtype GI cancers. The elevated antitumor immune signatures and PD-L1 expression could contribute to the more active immunotherapeutic responsiveness and better survival prognosis in ARID1A-mutated GI cancers than in ARID1A-wildtype GI cancers in the immunotherapy setting, as evidenced in three cancer cohorts receiving immunotherapy. Thus, the ARID1A mutation could be a useful biomarker for identifying GI cancer patients responsive to immunotherapy.

51Cr-release to monitor NK cell cytotoxicity

Natural killer (NK) cells are cytotoxic lymphocytes that belong to the innate lymphoid cells. They have the ability to attack tumor cells that lack ligands of inhibitory NK receptors and/or express ligands of activating NK receptors. The most important ligands of inhibitory NK receptors are major histocompatibility complex (MHC) class I molecules, which are down regulated on many tumor cells. Several ligands of activating NK receptors, in contrast, are up regulated on tumor cells due to cellular and genotoxic stress. Due to these features, NK cells constitute an important element of the tumor immunosurveillance and are explored as a cellular tool for tumor immunotherapy. Therefore, it is important to be able to monitor the cytotoxic activity of NK cells reliably in preclinical animal models as well as in patients. It is also of interest to determine the susceptibility of tumor cells toward NK cell-mediated cellular cytotoxicity. The ⁵¹Cr-release assay monitors the lysis of target cells by NK cells and is suitable to address both questions. We describe here the experimental set-up of this classic cytotoxicity assay in detail.

Quantifying NK cell growth and survival changes in response to cytokines and regulatory checkpoint blockade helps identify optimal culture and expansion conditions

NK cells are innate lymphocytes critical for immune surveillance, particularly in eradication of metastatic cancer cells and acute antiviral responses. In contrast to T cells, NK cell-mediated immunity is rapid, with spontaneous cytotoxicity and cytokine/chemokine production upon pathogen detection. The renaissance in cancer immunology has cast NK cell biology back into the spotlight with an urgent need for deeper understanding of the regulatory networks that govern NK cell antitumor activity. To this end, we have adapted and refined a series of quantitative cellular calculus methods, previously applied to T and B lymphocytes, to dissect the biologic outcomes of NK cells following stimulation with cytokines (IL-15, IL-12, IL-18) or deletion of genes that regulate NK cell proliferation (Cish), survival (Bcl2l11), and activation-induced-cell-death (AICD; Fas). Our methodology is well suited to delineate effects on division rate, intrinsic apoptosis, and AICD, permitting variables such as population half-life, rate of cell division, and their combined influence on population numbers in response to stimuli to be accurately measured and modelled. Changes in these variables that result from gene deletion, concentration of stimuli, time, and cell density give insight into the dynamics of NK cell responses and serve as a platform to dissect the mechanism of action of putative checkpoints in NK cell activation and novel NK cell immunotherapy agents.

The LNT model for cancer induction is not supported by radiobiological data

The hallmarks of cancer have been the focus of much research and have influenced the development of risk models for radiation-induced cancer. However, natural defenses against cancer, which constitute the hallmarks of cancer prevention, have largely been neglected in developing cancer risk models. These natural defenses are enhanced by low doses and dose rates of ionizing radiation, which has aided in the continuation of human life over many generations. Our natural defenses operate at the molecular, cellular, tissue, and whole-body levels and include epigenetically regulated (epiregulated) DNA damage repair and antioxidant production, selective p53-independent apoptosis of aberrant cells (e.g. neoplastically transformed and tumor cells), suppression of cancer-promoting inflammation, and anticancer immunity (both innate and adaptive components). This publication reviews the scientific bases for the indicated cancer-preventing natural defenses and evaluates their implication for assessing cancer risk after exposure to low radiation doses and dose rates. Based on the extensive radiobiological evidence reviewed, it is concluded that the linear-no-threshold (LNT) model (which ignores natural defenses against cancer), as it relates to cancer risk from ionizing radiation, is highly implausible. Plausible models include dose-threshold and hormetic models. More research is needed to establish when a given model (threshold, hormetic, or other) applies to a given low-dose-radiation exposure scenario.

Immunotherapy utilizing the combination of natural killer- and antibody dependent cellular cytotoxicity (ADCC)-mediating agents with poly (ADP-ribose) polymerase (PARP) inhibition

Background

Poly (ADP-ribose) polymerase inhibitors (PARPi) prevent single-stranded DNA repair. Olaparib is a PARPi approved for the treatment of BRCA mutant ovarian and breast carcinoma. Emerging clinical data suggest a benefit of combining olaparib with immunotherapy in prostate cancer patients both with and without somatic BRCA mutations.

Methods

We examined if olaparib, when combined with IgG₁ antibody-dependent cellular cytotoxicity (ADCC)-mediating monoclonal antibodies (mAbs) cetuximab (anti-EGFR), or avelumab (anti-PD-L1), would increase tumor cell sensitivity to killing by natural killer (NK) cells independently of BRCA status or mAb target upregulation. BRCA mutant and BRCA wildtype (WT) prostate carcinoma cell lines were pretreated with olaparib and then exposed to NK cells in the presence or absence of cetuximab or avelumab.

Results

NK-mediated killing was significantly increased in both cell lines and was further increased using the ADCC-mediating mAbs. Pre-exposure of NK cells to recombinant IL-15/IL-15Rα further increased the lysis of olaparib treated tumor cells. In addition, olaparib treated tumor cells were killed to a significantly greater degree by engineered high-affinity NK cells (haNK). We show here for the first time that (a) olaparib significantly increased tumor cell sensitivity to NK killing and ADCC in both BRCA WT and BRCA mutant prostate carcinoma cells, independent of PD-L1 or EGFR modulation; (b) mechanistically, treatment with olaparib upregulated death receptor TRAIL-R2; and (c) olaparib significantly enhanced NK killing of additional tumor types, including breast, non-small cell lung carcinoma, and chordoma.

Conclusions

These studies support the combined use of NK- and ADCC-mediating agents with correctly timed PARP inhibition.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0445-4) contains supplementary material, which is available to authorized users.

Tumor-Derived cGAMP Triggers a STING-Mediated Interferon Response in Non-tumor Cells to Activate the NK Cell Response

Detection of cytosolic DNA by the enzyme cGAS triggers the production of cGAMP, a second messenger that binds and activates the adaptor protein STING, which leads to interferon (IFN) production. Here, we found that in vivo natural killer (NK) cell killing of tumor cells, but not of normal cells, depends on STING expression in non-tumor cells. Experiments using transplantable tumor models in STING- and cGAS-deficient mice revealed that cGAS expression by tumor cells was critical for tumor rejection by NK cells. In contrast, cGAS expression by host cells was dispensable, suggesting that tumor-derived cGAMP is transferred to non-tumor cells, where it activates STING. cGAMP administration triggered STING activation and IFN-β production in myeloid cells and B cells but not NK cells. Our results reveal that the anti-tumor response of NK cells critically depends on the cytosolic DNA sensing pathway, similar to its role in defense against pathogens, and identify tumor-derived cGAMP as a major determinant of tumor immunogenicity with implications for cancer immunotherapy.

DNA damage and neurodegenerative phenotypes in aged Ciz1 null mice

Cell-cycle dysfunction and faulty DNA repair are closely intertwined pathobiological processes that may contribute to several neurodegenerative disorders. CDKN1A interacting zinc finger protein 1 (CIZ1) plays a critical role in DNA replication and cell-cycle progression at the G1/S checkpoint. Germline or somatic variants in CIZ1 have been linked to several neural and extra-neural diseases. Recently, we showed that germline knockout of Ciz1 is associated with motor and hematological abnormalities in young adult mice. However, the effects of CIZ1 deficiency in much older mice may be more relevant to understanding age-related declines in cognitive and motor functioning and age-related neurologic disorders such as isolated dystonia and Alzheimer disease. Mouse embryonic fibroblasts from Ciz1^-/- mice showed abnormal sensitivity to the effects of γ-irradiation with persistent DNA breaks, aberrant cell-cycle progression, and apoptosis. Aged (18-month-old) Ciz1^-/- mice exhibited marked deficits in motor and cognitive functioning, and, in brain tissues, overt DNA damage, NF-κB upregulation, oxidative stress, vascular dysfunction, inflammation, and cell death. These findings indicate that the deleterious effects of CIZ1 deficiency become more pronounced with aging and suggest that defects of cell-cycle control and associated DNA repair pathways in postmitotic neurons could contribute to global neurologic decline in elderly human populations. Accordingly, the G1/S cell-cycle checkpoint and associated DNA repair pathways may be targets for the prevention and treatment of age-related neurodegenerative processes.

Integrating the DNA damage and protein stress responses during cancer development and treatment

During evolution, cells have developed a wide spectrum of stress response modules to ensure homeostasis. The genome and proteome damage response pathways constitute the pillars of this interwoven 'defensive' network. Consequently, the deregulation of these pathways correlates with ageing and various pathophysiological states, including cancer. In the present review, we highlight: (1) the structure of the genome and proteome damage response pathways; (2) their functional crosstalk; and (3) the conditions under which they predispose to cancer. Within this context, we emphasize the role of oncogene-induced DNA damage as a driving force that shapes the cellular landscape for the emergence of the various hallmarks of cancer. We also discuss potential means to exploit key cancer-related alterations of the genome and proteome damage response pathways in order to develop novel efficient therapeutic modalities. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Immunosurveillance of cancer and the heat shock protein-CD91 pathway

The intracellular functions of heat shock proteins (HSPs) as chaperones of macromolecules are well known. Current observations point to a role of these chaperones in initiating and modulating immune responses to tumors via receptor(s) on dendritic cells. In this article we provide an insight into, and a basis for, the importance of these HSP-mediated immune responses in rejecting nascent and emerging tumors.