CD5 blockade enhances ex vivo CD8+ T cell activation and tumour cell cytotoxicity.

CD5 is expressed on T cells and a subset of B cells (B1a). It can attenuate TCR signalling and impair CTL activation and is a therapeutic targetable tumour antigen expressed on leukemic T and B cells. However, the potential therapeutic effect of functionally blocking CD5 to increase T cell anti-tumour activity against tumours (including solid tumours) has not been explored. CD5 knockout mice show increased anti-tumour immunity: reducing CD5 on CTLs may be therapeutically beneficial to enhance the anti-tumour response. Here, we show that ex vivo administration of a function-blocking anti-CD5 MAb to primary mouse CTLs of both tumour-naïve mice and mice bearing murine 4T1 breast tumour homografts enhanced their capacity to respond to activation by treatment with anti-CD3/anti-CD28 MAbs or 4T1 tumour cell lysates. Furthermore, it enhanced TCR signalling (ERK activation) and increased markers of T cell activation, including proliferation, CD69 levels, IFN-γ production, apoptosis and Fas receptor and Fas ligand levels. Finally, CD5 function-blocking MAb treatment enhanced the capacity of CD8+ T cells to kill 4T1-mouse tumour cells in an ex vivo assay. These data support the potential of blockade of CD5 function to enhance T cell-mediated anti-tumour immunity.

miRNA-5119 regulates immune checkpoints in dendritic cells to enhance breast cancer immunotherapy.

Dendritic cell (DC) based immunotherapy is a promising approach to clinical cancer treatment. miRNAs are a class of small non-coding RNA molecules that bind to RNAs to mediate multiple events which are important in diverse biological processes. miRNA mimics and antagomirs may be potent agents to enhance DC-based immunotherapy against cancers. miRNA array analysis was used to identify a representative miR-5119 potentially regulating PD-L1 in DCs. We evaluated levels of ligands of immune cell inhibitory receptors (IRs) and miR-5119 in DCs from immunocompetent mouse breast tumor-bearing mice, and examined the molecular targets of miR-5119. We report that miRNA-5119 was downregulated in spleen DCs from mouse breast cancer-bearing mice. In silico analysis and qPCR data showed that miRNA-5119 targeted mRNAs encoding multiple negative immune regulatory molecules, including ligands of IRs such as PD-L1 and IDO2. DCs engineered to express a miR-5119 mimic downregulated PD-L1 and prevented T cell exhaustion in mice with breast cancer homografts. Moreover, miR-5119 mimic-engineered DCs effectively restored function to exhausted CD8+ T cells in vitro and in vivo, resulting in robust anti-tumor cell immune response, upregulated cytokine production, reduced T cell apoptosis, and exhaustion. Treatment of 4T1 breast tumor-bearing mice with miR-5119 mimic-engineered DC vaccine reduced T cell exhaustion and suppressed mouse breast tumor homograft growth. This study provides evidence supporting a novel therapeutic approach using miRNA-5119 mimic-engineered DC vaccines to regulate inhibitory receptors and enhance anti-tumor immune response in a mouse model of breast cancer. miRNA/DC-based immunotherapy has potential for advancement to the clinic as a new strategy for DC-based anti-breast cancer immunotherapy.

Supplementing preservation solution with mitochondria-targeted H2 S donor AP39 protects cardiac grafts from prolonged cold ischemia-reperfusion injury in heart transplantation.

Heart transplant has been accepted as the standard treatment for end-stage heart failure. Because of its susceptibility to ischemia-reperfusion injury, the heart can be preserved for only 4 to 6 hours in cold static preservation solutions. Prolonged ischemia time is adversely associated with primary graft function and long-term survival. New strategies to preserve donor hearts are urgently needed. We demonstrate that AP39, a mitochondria-targeting hydrogen sulfide donor, significantly increases cardiomyocyte viability and reduces cell apoptosis/death after cold hypoxia/reoxygenation in vitro. It also decreases gene expression of proinflammatory cytokines and preserves mitochondria function. Using an in vivo murine heart transplant model, we show that preserving donor hearts with AP39-supplemented University of Wisconsin solution (n = 7) significantly protects heart graft function, measured by quantitative ultrasound scan, against prolonged cold ischemia-reperfusion injury (24 hours at 4°C), along with reducing tissue injury and fibrosis. Our study demonstrates that supplementing preservation solution with AP39 protects cardiac grafts from prolonged ischemia, highlighting its therapeutic potential in preventing ischemia-reperfusion injury in heart transplant.

CD5 blockade, a novel immune checkpoint inhibitor, enhances T cell anti-tumour immunity and delays tumour growth in mice harbouring poorly immunogenic 4T1 breast tumour homografts.

CD5 is a member of the scavenger receptor cysteine-rich superfamily that is expressed on T cells and a subset of B cells (B1a) cell and can regulate the T cell receptor signaling pathway. Blocking CD5 function may have therapeutic potential in treatment of cancer by enhancing cytotoxic T lymphocyte recognition and ablation of tumour cells. The effect of administering an anti-CD5 antibody to block or reduce CD5 function as an immune checkpoint blockade to enhance T cell anti-tumour activation and function in vivo has not been explored. Here we challenged mice with poorly immunogenic 4T1 breast tumour cells and tested whether treatment with anti-CD5 monoclonal antibodies (MAb) in vivo could enhance non-malignant T cell anti-tumour immunity and reduce tumour growth. Treatment with anti-CD5 MAb resulted in an increased fraction of CD8+ T cells compared to CD4+ T cell in draining lymph nodes and the tumour microenvironment. In addition, it increased activation and effector function of T cells isolated from spleens, draining lymph nodes, and 4T1 tumours. Furthermore, tumour growth was delayed in mice treated with anti-CD5 MAb. These data suggest that use of anti-CD5 MAb as an immune checkpoint blockade can both enhance activation of T cells in response to poorly immunogenic antigens and reduce tumour growth in vivo. Exploration of anti-CD5 therapies in treatment of cancer, alone and in combination with other immune therapeutic drugs, is warranted.

The impact of antibiotic use in gastrointestinal tumors treated with immune checkpoint inhibitors: systematic review and meta-analysis.

Background: Immune checkpoint inhibitors (ICI) have improved overall survival in patients with different cancer types. However, treatment efficacy varies between patients depending on several factors. Recent research suggested that antibiotic-induced dysbiosis can impair ICI efficacy. Here we review the impact of antibiotic use in clinical outcome of patients with gastrointestinal cancer treated with ICI. Methods: This is a systematic review and utilized a thorough search of MEDLINE, Cochrane, Scopus, EB-SCO, Web of Science of studies published till September 2023. The aim of the study is to determine the association between antibiotic use and ICI treatment efficacy in patients with gastrointestinal cancers (GI). We utilized a meta-analysis of the association between the use of antibiotics and overall survival and progression-free survival. Results: Nine studies met the inclusion criteria with a total of 2,214 patients. The most common type of cancers was hepatocellular carcinoma (HCC). The majority of the studies were retrospective, and one was collective of clinical trials. The use of antibiotics was associated with decreased both overall survival [haz-ard ratio (HR) 1.92, 95% confidence interval (CI) 1.41, 2.63] and progression-free survival [HR 1.81, 95% CI 1.29, 2.54]. Conclusion: The use of antibiotics may affect clinical outcomes in patients with GI cancers treated with ICI. Further prospective studies are needed to improve the understanding of this phenomenon. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023462172.

Interactions of proteins with heparan sulfate.

Heparan sulfate (HS) is a glycosaminoglycan, polysaccharides that are considered to have arisen in the last common unicellular ancestor of multicellular animals. In this light, the large interactome of HS and its myriad functions in relation to the regulation of cell communication are not surprising. The binding of proteins to HS determines their localisation and diffusion, essential for embryonic development and homeostasis. Following the biosynthesis of the initial heparosan polymer, the subsequent modifications comprise an established canonical pathway and a minor pathway. The more frequent former starts with N-deacetylation and N-sulfation of GlcNAc residues, the latter with C-5 epimerisation of a GlcA residue adjacent to a GlcNAc. The binding of proteins to HS is driven by ionic interactions. The multivalent effect arising from the many individual ionic bonds between a single protein and a polysaccharide chain results in a far stronger interaction than would be expected from an ion-exchange process. In many instances, upon binding, both parties undergo substantial conformational change, the resulting hydrogen and van der Waal bonds contributing significant free energy to the binding reaction. Nevertheless, ionic bonds dominate the protein-polysaccharide interaction kinetically. Together with the multivalent effect, this provides an explanation for the observed trapping of HS-binding proteins in extracellular matrix. Importantly, individual ionic bonds have been observed to be dynamic; breaking and reforming, while the protein remains bound to the polysaccharide. These considerations lead to a model for 1D diffusion of proteins in extracellular matrix on HS, involving mechanisms such as sliding, chain switching and rolling.

Exosomal microRNAs in cancer: Potential biomarkers and immunotherapeutic targets for immune checkpoint molecules.

Exosomes are small extracellular vesicles with a lipid bilayer structure secreted from different cell types which can be found in various body fluids including blood, pleural fluid, saliva and urine. They carry different biomolecules including proteins, metabolites, and amino acids such as microRNAs which are small non-coding RNAs that regulate gene expression and promote cell-to-cell communication. One main function of the exosomal miRNAs (exomiRs) is their role in cancer pathogenesis. Alternation in exomiRs expression could indicate disease progression and can regulate cancer growth and facilitate drug response/resistance. It can also influence the tumour microenvironment by controlling important signaling that regulating immune checkpoint molecules leading to activation of T cell anti-tumour immunity. Therefore, they can be used as potential novel cancer biomarkers and innovative immunotherapeutic agents. This review highlights the use of exomiRs as potential reliable biomarkers for cancer diagnosis, treatment response and metastasis. Finally, discuses their potential as immunotherapeutic agents to regulate immune checkpoint molecules and promote T cell anti-tumour immunity.

Destabilizing the genome as a therapeutic strategy to enhance response to immune checkpoint blockade: a systematic review of clinical trials evidence from solid and hematological tumors.

Background: Genomic instability is increased alterations in the genome during cell division and is common among most cancer cells. Genome instability enhances the risk of initial carcinogenic transformation, generating new clones of tumor cells, and increases tumor heterogeneity. Although genome instability contributes to malignancy, it is also an "Achilles' heel" that constitutes a therapeutically-exploitable weakness-when sufficiently advanced, it can intrinsically reduce tumor cell survival by creating DNA damage and mutation events that overwhelm the capacity of cancer cells to repair those lesions. Furthermore, it can contribute to extrinsic survival-reducing events by generating mutations that encode new immunogenic antigens capable of being recognized by the immune system, particularly when anti-tumor immunity is boosted by immunotherapy drugs. Here, we describe how genome-destabilization can induce immune activation in cancer patients and systematically review the induction of genome instability exploited clinically, in combination with immune checkpoint blockade. Methods: We performed a systematic review of clinical trials that exploited the combination approach to successfully treat cancers patients. We systematically searched PubMed, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, and publication from the reference list of related articles. The most relevant inclusion criteria were peer-reviewed clinical trials published in English. Results: We identified 1,490 studies, among those 164 were clinical trials. A total of 37 clinical trials satisfied the inclusion criteria and were included in the study. The main outcome measurements were overall survival and progression-free survival. The majority of the clinical trials (30 out of 37) showed a significant improvement in patient outcome. Conclusion: The majority of the included clinical trials reported the efficacy of the concept of targeting DNA repair pathway, in combination with immune checkpoint inhibitors, to create a "ring of synergy" to treat cancer with rational combinations.

The Risk Factors for Acute Cerebrovascular Accident (Stroke) in Patients with Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2).

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) patients may experience an acute ischemic stroke; however, risk factors, in-hospital deaths, and outcomes have not been thoroughly investigated. This study investigates the risk factors, comorbidities, and outcomes in patients with SARS-VoV-2 infection and acute ischemic stroke compared to patients without these conditions. The present retrospective study was conducted in the King Abdullah International Medical Research Centre (KAIMRC), Ministry of National Guard, Health Affairs, Riyadh, Saudi Arabia, during the period from April 2020 to February 2022. This study investigates the risk variables among the individuals who were diagnosed with either SARS-CoV-2 with stroke or patients with stroke alone. A total of 42,688 COVID-19 patients were registered, 187 cases of strokes were listed in COVID-19 patients, however, 5395 cases with stroke without SARS-CoV-2 infection. The results revealed that factors including age, hypertension, deep vein thrombosis, and ischemic heart disease are associated with an increased risk of ischemic stroke. The results also displayed an elevated frequency of in-hospital deaths in COVID-19 patients with acute ischemic stroke. The results also showed that SARS-CoV-2 together predicts the probability of stroke and death in the study sample. The study findings conclude that ischemic strokes were infrequent in patients with SARS-CoV-2 and usually occur in the presence of other risk factors. The risk factors of ischemic strokes in patients with SARS-CoV-2 are old age, male gender, hypertension, hyperlipidaemia, DVT, ischemic heart disease, and diabetes mellitus. Furthermore, the results showed a higher frequency of in-hospital deaths in COVID-19 patients with stroke compared to COVID-19 patients without stroke.

Antibiotic Exposure Concurrently with Anti-PD1 Blockade Therapy Reduces Overall Survival in Patients with Child-Pugh Class A Advanced Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide with a poor prognosis. Treatment with immune checkpoint inhibitors (ICIs) has improved overall survival in patients with HCC. However, not all patients benefit from the treatment. In this study, 59 patients with HCC were enrolled from two medical centers in Saudi Arabia, with 34% using antibiotics concurrently with their Nivolumab (anti-PD1 blockade). The impact of antibiotic use on the clinical outcomes of patients with HCC undergoing treatment with anti-PD1 blockade was examined. The patients' overall survival (OS) was 5 months (95% CI: 3.2, 6.7) compared to 10 months (95% CI: 0, 22.2) (p = 0.08). Notably, patients with Child-Pugh A cirrhosis receiving anti-PD1 blockade treatment without concurrent antibiotic use showed a significantly longer median OS reaching 22 months (95% CI: 6.5, 37.4) compared to those who were given antibiotics with a median OS of 6 months (95% CI: 2.7, 9.2) (p = 0.02). This difference in overall survival was particularly found in Child-Pugh class A patients receiving anti-PD1 blockade. These findings suggest that antibiotic use may negatively affect survival outcomes in HCC patients undergoing anti-PD1 blockade, potentially due to antibiotic-induced alterations to the gut microbiome impacting the anti-PD1 blockade response. This study suggests the need for careful consideration when prescribing antibiotics to patients with HCC receiving anti-PD1 blockade.

Type I interferon autoantibodies in hospitalized patients with Middle East respiratory syndrome and association with outcomes and treatment effect of interferon beta-1b in MIRACLE clinical trial.

Background: Type I interferons (IFNs) are essential antiviral cytokines induced upon respiratory exposure to coronaviruses. Defects in type I IFN signaling can result in severe disease upon exposure to respiratory viral infection and are associated with worse clinical outcomes. Neutralizing autoantibodies (auto-Abs) to type I IFNs were reported as a risk factor for life-threatening COVID-19, but their presence has not been evaluated in patients with severe Middle East respiratory syndrome (MERS). Methods: We evaluated the prevalence of type I IFN auto-Abs in a cohort of hospitalized patients with MERS who were enrolled in a placebo-controlled clinical trial for treatment with IFN-ß1b and lopinavir-ritonavir (MIRACLE trial). Samples were tested for type I IFN auto-Abs using a multiplex particle-based assay. Results: Among the 62 enrolled patients, 15 (24.2%) were positive for immunoglobulin G auto-Abs for at least one subtype of type I IFNs. Auto-Abs positive patients were not different from auto-Abs negative patients in age, sex, or comorbidities. However, the majority (93.3%) of patients who were auto-Abs positive were critically ill and admitted to the ICU at the time of enrollment compared to 66% in the auto-Abs negative patients. The effect of treatment with IFN-ß1b and lopinavir-ritonavir did not significantly differ between the two groups. Conclusion: This study demonstrates the presence of type I IFN auto-Abs in hospitalized patients with MERS.

Reduced CD5 on CD8+ T Cells in Tumors but Not Lymphoid Organs Is Associated With Increased Activation and Effector Function.

CD5, a member of the scavenger receptor cysteine-rich superfamily, is a marker for T cells and a subset of B cells (B1a). CD5 associates with T-cell and B-cell receptors and increased CD5 is an indication of B cell activation. In tumor-infiltrating lymphocytes (TILs) isolated from lung cancer patients, CD5 levels were negatively correlated with anti-tumor activity and tumor-mediated activation-induced T cell death, suggesting that CD5 could impair activation of anti-tumor T cells. We determined CD5 levels in T cell subsets in different organs in mice bearing syngeneic 4T1 breast tumor homografts and assessed the relationship between CD5 and increased T cell activation and effector function by flow cytometry. We report that T cell CD5 levels were higher in CD4+ T cells than in CD8+ T cells in 4T1 tumor-bearing mice, and that high CD5 levels on CD4+ T cells were maintained in peripheral organs (spleen and lymph nodes). However, both CD4+ and CD8+ T cells recruited to tumors had reduced CD5 compared to CD4+ and CD8+ T cells in peripheral organs. In addition, CD5high/CD4+ T cells and CD5high/CD8+ T cells from peripheral organs exhibited higher levels of activation and associated effector function compared to CD5low/CD4+ T cell and CD5low/CD8+ T cell from the same organs. Interestingly, CD8+ T cells among TILs and downregulated CD5 were activated to a higher level, with concomitantly increased effector function markers, than CD8+/CD5high TILs. Thus, differential CD5 levels among T cells in tumors and lymphoid organs can be associated with different levels of T cell activation and effector function, suggesting that CD5 may be a therapeutic target for immunotherapeutic activation in cancer therapy.

Effects of Combined Nicotine and Caffeine on the Rat Skeletal Muscles: A Histological and Immunohistochemical Study.

BACKGROUND: Nicotine and caffeine are pharmacologically active substances that consumed widely in the whole world. Most of the nicotine users also consume caffeine. Smokers tend to drink more coffee than nonsmokers. It is important to characterize these substances with regard to their effects on the histological and immunohistological structure. OBJECTIVES: The objective of the study is to assess the impact of combined administration of nicotine and caffeine on histological structure of the skeletal muscle tissue in the adult male Wistar rats. MATERIALS AND METHODS: Twenty adult male Wistar rats with an average weight of 200-250 g were randomly divided into four equal groups: control, nicotine, caffeine, and combined (nicotine + caffeine). The diaphragm muscle was processed and stained with hematoxylin and eosin (H and E) stain, histochemically by periodic acid-Schiff (PAS) and immunohistochemically by anti-CD68 antibodies. RESULTS: After injected nicotine, thick basement membrane with apparent increase in the positive CD68 macrophages inbetween the diaphragm muscle fibers. After injected caffeine, there was an apparent accumulation of mononuclear cells around some fibers with decrease in the PAS positive fibers. Combined injected (nicotine + caffeine) group, some fibers exhibited deep acidophilic cytoplasm with flat peripheral nuclei and apparent increase of the CD68 positive cells. There was an increase in PAS positive material around fibers appearing as a thick basement membrane. CONCLUSIONS: The present study proved that caffeine and nicotine either taken alone or in combination have many negative impacts on the active type of skeletal muscles like diaphragm leading to degenerative changes that may affect their function.

miR-149-3p reverses CD8+ T-cell exhaustion by reducing inhibitory receptors and promoting cytokine secretion in breast cancer cells.

Blockade of inhibitory receptors (IRs) is one of the most effective immunotherapeutic approaches to treat cancer. Dysfunction of miRNAs is a major cause of aberrant expression of IRs and contributes to the immune escape of cancer cells. How miRNAs regulate immune checkpoint proteins in breast cancer remains largely unknown. In this study, downregulation of miRNAs was observed in PD-1-overexpressing CD8+ T cells using miRNA array analysis of mouse breast cancer homografts. The data reveal that miR-149-3p was predicted to bind the 3'UTRs of mRNAs encoding T-cell inhibitor receptors PD-1, TIM-3, BTLA and Foxp1. Treatment of CD8+ T cells with an miR-149-3p mimic reduced apoptosis, attenuated changes in mRNA markers of T-cell exhaustion and downregulated mRNAs encoding PD-1, TIM-3, BTLA and Foxp1. On the other hand, T-cell proliferation and secretion of effector cytokines indicative of increased T-cell activation (IL-2, TNF-α, IFN-γ) were upregulated after miR-149-3p mimic treatment. Moreover, the treatment with a miR-149-3p mimic promoted the capacity of CD8+ T cells to kill targeted 4T1 mouse breast tumour cells. Collectively, these data show that miR-149-3p can reverse CD8+ T-cell exhaustion and reveal it to be a potential antitumour immunotherapeutic agent in breast cancer.