Immune Evasion Research Articles

Exploration and Validation of Lead Molecules against Yellow Fever through High Throughput Virtual Screening and Molecular Dynamics Simulation

Background: Yellow fever (YF) is a mosquito-borne flaviviral hemorrhagic fever (VHF) that causes severe hepatitis, renal failure, bleeding, and quick terminal events such as shock and multi-organ failure. There are currently no particular anti-viral medications for the management of the YF virus (YFV). Despite the availability of a commercial YFV vaccination, there are roughly 30,000 fatalities globally each year, with instances rising over the previous 20 years. After being translocated into the endoplasmic reticulum lumen, glycosylated NS1 resides as a membrane-associated dimer, where it is required for viral genome replication. The secreted hexamer NS1 has a role in immune evasion and pathogenesis and has been discovered as a possible diagnostic marker for the early identification of viral infections. Objective: The main aim of this study is to analyze the small molecule as a potent drug candidate against the target NS1 protein. Methods: In this study, Computational approaches, including high throughput virtual screening, molecular docking, and dynamics simulation, were carried out against the target NS1 protein using three different chemical libraries Enamine, Asinex, and NCI. The selected lead compounds were validated through HOMO-LUMO analysis, ADME prediction, and Toxicity parameters to analyze the biological and pharmacological properties of the lead small molecules. Results: From the result, it was concluded that the leads possessed the highest docking scores, interacting with the binding residues, and were stable in the simulation period. Conclusion: Overall findings revealed that the lead three small molecules could act as the potential drug candidate for the target NS1 protein to inhibit the diseasing efficacy of Yellow fever.

CT109-SN-38, a Novel Antibody-drug Conjugate with Dual Specificity for CEACAM5 and 6, Elicits Potent Killing of Pancreatic Cancer Cells.

CEACAM5 and CEACAM6 are glycosylphosphatidylinositol (GPI)- linked members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family, which are frequently upregulated in epithelial cancers where they contribute to invasion, metastasis, immune evasion, and resistance to anoikis. CT109 is a novel antibody with dual specificity to both CEACAM5 and 6. In this study, we aimed to perform the preclinical characterization of CT109 and antibody- drug conjugate (ADCs) derivatives of CT109, focusing on CT109-SN-38. CT109's cognate epitope was characterized by scanning mutagenesis. CT109 specificity and internalization kinetics were assessed by immunoblot and flow cytometry, respectively. Cognate antigen expression prevalence in colorectal cancer and normal tissue arrays was determined by immunohistochemistry. CT109 conjugations were generated by the reaction of reduced CT109 cysteines with maleimide-functionalized payload linkers. In vitro cytotoxic activity of CT109 ADCs was characterized on antigen-positive and negative pancreatic ductal adenocarcinoma cell (PDAC) lines using a luminometric viability assay. In vivo efficacy of CT109-SN-38 was assessed on a PDAC tumor xenograft model at 10 and 25 mg/kg concentrations. CT109 showed to bind a glycoepitope centered on N309. CT109 is internalized in the CEACAM5+/CEACAM6+ double-positive PDAC line, BxPC-3, with a t1/2 of 2.3 hours. CT109 ADCs elicit a dose and antigen-dependent cytotoxic effect, with CT109-SN-38 exhibiting an IC50 value of 21 nM in BxPC-3 cells. In a BxPC-3 tumor xenograft model, CT109-SN-38 reduced tumor growth and induced regression in 3/10 mice at 25 mg/kg concentration. These data suggest that further preclinical and clinical development of CT109-SN-38 is warranted.

Immunosuppressive regulatory cells in cancer immunotherapy: restrain or modulate?

Immunosuppressive regulatory cells (IRCs) play important roles in negatively regulating immune response, and are mainly divided into myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). Large numbers of preclinical and clinical studies have shown that inhibition or reduction of IRCs could effectively elevate antitumor immune responses. However, several studies also reported that excessive inhibition of IRCs function is one of the main reasons causing the side effects of cancer immunotherapy. Therefore, the reasonable regulation of IRCs is crucial for improving the safety and efficiency of cancer immunotherapy. In this review, we summarised the recent research advances in the cancer immunotherapy by regulating the proportion of IRCs, and discussed the roles of IRCs in regulating tumour immune evasion and drug resistance to immunotherapies. Furthermore, we also discussed how to balance the potential opportunities and challenges of using IRCs to improve the safety of cancer immunotherapies.

HMMR triggers immune evasion of hepatocellular carcinoma by inactivation of phagocyte killing.

Hepatocellular carcinoma (HCC) acquires an immunosuppressive microenvironment, leading to unbeneficial therapeutic outcomes. Hyaluronan-mediated motility receptor (HMMR) plays a crucial role in tumor progression. Here, we found that aberrant expression of HMMR could be a predictive biomarker for the immune suppressive microenvironment of HCC, but the mechanism remains unclear. We established an HMMR-/- liver cancer mouse model to elucidate the HMMR-mediated mechanism of the dysregulated "don't eat me" signal. HMMR knockout inhibited liver cancer growth and induced phagocytosis. HMMRhigh liver cancer cells escaped from phagocytosis via sustaining CD47 signaling. Patients with HMMRhighCD47high expression showed a worse prognosis than those with HMMRlowCD47low expression. HMMR formed a complex with FAK/SRC in the cytoplasm to activate NF-κB signaling, which could be independent of membrane interaction with CD44. Notably, targeting HMMR could enhance anti-PD-1 treatment efficiency by recruiting CD8+ T cells. Overall, our data revealed a regulatory mechanism of the "don't eat me" signal and knockdown of HMMR for enhancing anti-PD-1 treatment.

Function and contribution of two putative Enterococcus faecalis glycosaminoglycan degrading enzymes to bacteremia and catheter-associated urinary tract infection.

Enterococcus faecalis is a common cause of healthcare-acquired bloodstream infections and catheter-associated urinary tract infections (CAUTIs) in both adults and children. Treatment of E. faecalis infection is frequently complicated by multi-drug resistance. Based on protein homology, E. faecalis encodes two putative hyaluronidases, EF3023 (HylA) and EF0818 (HylB). In other Gram-positive pathogens, hyaluronidases have been shown to contribute to tissue damage and immune evasion, but the function in E. faecalis has yet to be explored. Here, we show that both hylA and hylB contribute to E. faecalis pathogenesis. In a CAUTI model, ΔhylA exhibited defects in bladder colonization and dissemination to the bloodstream, and ΔhylB exhibited a defect in kidney colonization. Furthermore, a ΔhylAΔhylB double mutant exhibited a severe colonization defect in a model of bacteremia while the single mutants colonized to a similar level as the wild-type strain, suggesting potential functional redundancy within the bloodstream. We next examined enzymatic activity, and demonstrate that HylB is capable of digesting both hyaluronic acid (HA) and chondroitin sulfate in vitro, while HylA exhibits only a very modest activity against heparin. Importantly, HA degradation by HylB provided a modest increase in cell density during the stationary phase and also contributed to dampening of lipopolysaccharide-mediated NF-κB activation. Overall, these data demonstrate that glycosaminoglycan degradation is important for E. faecalis pathogenesis in the urinary tract and during bloodstream infection.

Genetic Variations of African Swine Fever Virus: Major Challenges and Prospects.

African swine fever (ASF) is a contagious viral disease affecting pigs and wild boars. It typically presents as a hemorrhagic fever but can also manifest in various forms, ranging from acute to asymptomatic. ASF has spread extensively globally, significantly impacting the swine industry. The complex and highly variable character of the ASFV genome makes vaccine development and disease surveillance extremely difficult. The overall trend in ASFV evolution is towards decreased virulence and increased transmissibility. Factors such as gene mutation, viral recombination, and the strain-specificity of virulence-associated genes facilitate viral variations. This review deeply discusses the influence of these factors on viral immune evasion, pathogenicity, and the ensuing complexities encountered in vaccine development, disease detection, and surveillance. The ultimate goal of this review is to thoroughly explore the genetic evolution patterns and variation mechanisms of ASFV, providing a theoretical foundation for advancement in vaccine and diagnostic technologies.

Hallmarks of tumor-experienced T cells are absent in multiple myeloma patients from diagnosis through maintenance therapy.

Dysregulation of the bone marrow (BM) niche in multiple myeloma (MM) alters the composition and state of resident immune cells, potentially impeding anti-tumor immunity. One common mechanism of immune inhibition in solid tumors is the induction of exhaustion in tumor-specific T cells. However, the extent of T cell tumor recognition and exhaustion is not well-characterized in MM. As the specific mechanisms of immune evasion are critical for devising effective therapeutic strategies, we deeply profiled the CD8+ T cell compartment of newly-diagnosed MM (NDMM) patients for evidence of tumor reactivity and T cell exhaustion. We applied single-cell multi-omic sequencing and antigen-specific mass cytometry to longitudinal BM and peripheral blood (PB) samples taken from timepoints spanning from diagnosis through induction therapy, autologous stem cell transplant (ASCT), and maintenance therapy. We identified an exhausted-like population that lacked several canonical exhaustion markers, was not significantly enriched in NDMM patients, and consisted of small, nonpersistent clones. We also observed an activated population with increased frequency in the PB of NDMM patients exhibiting phenotypic and clonal features consistent with homeostatic, antigen-nonspecific activation. However, there was no evidence of "tumor-experienced" T cells displaying hallmarks of terminal exhaustion and/or tumor-specific activation/expansion in NDMM patients at any timepoint.

Why does circadian timing of administration matter for immune checkpoint inhibitors' efficacy?

Tolerability and antitumour efficacy of chemotherapy and radiation therapy can vary largely according to their time of administration along the 24-h time scale, due to the moderation of their molecular and cellular mechanisms by circadian rhythms. Recent clinical data have highlighted a striking role of dosing time for cancer immunotherapy, thus calling for a critical evaluation. Here, we review the clinical data and we analyse the mechanisms through which circadian rhythms can influence outcomes on ICI therapies. We examine how circadian rhythm disorders can affect tumour immune microenvironment, as a main mechanism linking the circadian clock to the 24-h cycles in ICIs antitumour efficacy. Real-life data from 18 retrospective studies have revealed that early time-of-day (ToD) infusion of immune checkpoint inhibitors (ICIs) could enhance progression-free and/or overall survival up to fourfold compared to late ToD dosing. The studies involved a total of 3250 patients with metastatic melanoma, lung, kidney, bladder, oesophageal, stomach or liver cancer from 9 countries. Such large and consistent differences in ToD effects on outcomes could only result from a previously ignored robust chronobiological mechanism. The circadian timing system coordinates cellular, tissue and whole-body physiology along the 24-h timescale. Circadian rhythms are generated at the cellular level by a molecular clock system that involves 15 specific clock genes. The disruption of circadian rhythms can trigger or accelerate carcinogenesis, and contribute to cancer treatment failure, possibly through tumour immune evasion resulting from immunosuppressive tumour microenvironment. Such emerging understanding of circadian rhythms regulation of antitumour immunity now calls for randomised clinical trials of ICIs timing to establish recommendations for personalised chrono-immunotherapies with current and forthcoming drugs.

Nonstructural Protein A238L of the African Swine Fever Virus (ASFV) Enhances Antiviral Immune Responses by Activating the TBK1-IRF3 Pathway.

African swine fever virus (ASFV) is a double-stranded DNA virus with an envelope. ASFV has almost the largest genome among all DNA viruses, and its mechanisms of immune evasion are complex. Better understanding of the molecular mechanisms of ASFV genes will improve vaccine design. A238L, a nonstructural protein of ASFV, inhibits NF-κB activation by suppressing the HAT activity of p300. Whether A238L also affects the transcriptional activity of IRF3 remains unexplored. Here we first confirmed the ability of A238L to suppress NF-κB-activity in L929 cells. A238L inhibits the expression of proinflammatory cytokine genes. In contrast, A238L increased the phosphorylation levels of TBK1 and IRF3 in three different cell lines. A238L increases the IRF3-driven promoter activity and induces IRF3 nuclear translocation. Furthermore, A238L enhanced innate antiviral immunity in the absence or presence of poly d (A:T) or poly (I:C) stimulation, or herpes simplex virus type 1 (HSV-1) or Sendai virus (SeV) infection. This study reveals a previously unrecognized role of A238L in promoting antiviral immune responses by TBK1-IRF3 pathway activation.

Human cytomegalovirus UL23 exploits PD-L1 inhibitory signaling pathway to evade T cell-mediated cytotoxicity.

T cell immunity is pivotal in controlling primary human cytomegalovirus (HCMV) infection, restricting periodic reactivation, and preventing HCMV-associated diseases. Despite inducing a robust T cell immune response, HCMV has developed sophisticated immune evasion mechanisms that specifically target T cell responses. Although numerous studies have been conducted on HCMV-specific T cells, the primary focus has been on the impact of HCMV on T cell recognition via major histocompatibility complex molecules. Our studies show for the first time that HCMV exploits the programmed death ligand 1 (PD-L1) inhibitory signaling pathway to evade T cell immunity by modulating the activities of T cells and thereby blocking the secretion of IFN-γ, which is directly mediated by HCMV-encoded tegument protein UL23. While PD-L1 has been extensively studied in the context of tumors and viruses, its involvement in HCMV infection and viral immune evasion is rarely reported. We observed an upregulation of PD-L1 in normal cells during HCMV infection and provided strong evidence supporting its critical role in UL23-induced inhibition of T cell-mediated cytotoxicity. The novel strategy employed by HCMV to manipulate the inhibitory signaling pathway of T cell immune activation for viral evasion through its encoded protein offers valuable insights for the understanding of HCMV-mediated T cell immunomodulation and developing innovative antiviral treatment strategies.

DUX4 is a common driver of immune evasion and immunotherapy failure in metastatic cancers

Cancer immune evasion contributes to checkpoint immunotherapy failure in many patients with metastatic cancers. The embryonic transcription factor DUX4 was recently characterized as a suppressor of interferon-γ signaling and antigen presentation that is aberrantly expressed in a small subset of primary tumors. Here, we report that DUX4 expression is a common feature of metastatic tumors, with ~10–50% of advanced bladder, breast, kidney, prostate, and skin cancers expressing DUX4. DUX4 expression is significantly associated with immune cell exclusion and decreased objective response to PD-L1 blockade in a large cohort of urothelial carcinoma patients. DUX4 expression is a significant predictor of survival even after accounting for tumor mutational burden and other molecular and clinical features in this cohort, with DUX4 expression associated with a median reduction in survival of over 1 year. Our data motivate future attempts to develop DUX4 as a biomarker and therapeutic target for checkpoint immunotherapy resistance.

DUX4 is a common driver of immune evasion and immunotherapy failure in metastatic cancers.

Cancer immune evasion contributes to checkpoint immunotherapy failure in many patients with metastatic cancers. The embryonic transcription factor DUX4 was recently characterized as a suppressor of interferon-γ signaling and antigen presentation that is aberrantly expressed in a small subset of primary tumors. Here, we report that DUX4 expression is a common feature of metastatic tumors, with ~10-50% of advanced bladder, breast, kidney, prostate, and skin cancers expressing DUX4. DUX4 expression is significantly associated with immune cell exclusion and decreased objective response to PD-L1 blockade in a large cohort of urothelial carcinoma patients. DUX4 expression is a significant predictor of survival even after accounting for tumor mutational burden and other molecular and clinical features in this cohort, with DUX4 expression associated with a median reduction in survival of over 1 year. Our data motivate future attempts to develop DUX4 as a biomarker and therapeutic target for checkpoint immunotherapy resistance.

Fibrotic tumors tune metabolism for immune evasion.

Fibrotic tumors tune metabolism for immune evasion.

Antitumor efficacy and potential mechanism of FAP-targeted radioligand therapy combined with immune checkpoint blockade

Radiotherapy combined with immune checkpoint blockade holds great promise for synergistic antitumor efficacy. Targeted radionuclide therapy delivers radiation directly to tumor sites. LNC1004 is a fibroblast activation protein (FAP)-targeting radiopharmaceutical, conjugated with the albumin binder Evans Blue, which has demonstrated enhanced tumor uptake and retention in previous preclinical and clinical studies. Herein, we demonstrate that 68Ga/177Lu-labeled LNC1004 exhibits increased uptake and prolonged retention in MC38/NIH3T3-FAP and CT26/NIH3T3-FAP tumor xenografts. Radionuclide therapy with 177Lu-LNC1004 induced a transient upregulation of PD-L1 expression in tumor cells. The combination of 177Lu-LNC1004 and anti-PD-L1 immunotherapy led to complete eradication of all tumors in MC38/NIH3T3-FAP tumor-bearing mice, with mice showing 100% tumor rejection upon rechallenge. Immunohistochemistry, single-cell RNA sequencing (scRNA-seq), and TCR sequencing revealed that combination therapy reprogrammed the tumor microenvironment in mice to foster antitumor immunity by suppressing malignant progression and increasing cell-to-cell communication, CD8+ T-cell activation and expansion, M1 macrophage counts, antitumor activity of neutrophils, and T-cell receptor diversity. A preliminary clinical study demonstrated that 177Lu-LNC1004 was well-tolerated and effective in patients with refractory cancers. Further, scRNA-seq of peripheral blood mononuclear cells underscored the importance of addressing immune evasion through immune checkpoint blockade treatment. This was emphasized by the observed increase in antigen processing and presentation juxtaposed with T cell inactivation. In conclusion, our data supported the efficacy of immunotherapy combined with 177Lu-LNC1004 for cancer patients with FAP-positive tumors.

FAT10 induces immune suppression by upregulating PD-L1 expression in hepatocellular carcinoma.

The upregulation of programmed death ligand 1 (PD-L1) plays a crucial role in facilitating cancer cells to evade immune surveillance through immunosuppression. However, the precise regulatory mechanisms of PD-L1 in hepatocellular carcinoma (HCC) remain undefined. The correlation between PD-L1 and ubiquitin-like molecules (UBLs) was studied using sequencing data from 20 HCC patients in our center, combined with TCGA data. Specifically, the association between FAT10 and PD-L1 was further validated at both the protein and mRNA levels in HCC tissues from our center. Subsequently, the effect of FAT10 on tumor progression and immune suppression was examined through both in vivo and in vitro experiments. Utilizing sequencing data, qPCR, and Western blotting assays, we confirmed that FAT10 was highly expressed in HCC tissues and positively correlated with PD-L1 expression. Additionally, in vitro experiments demonstrated that the overexpression of FAT10 fostered the proliferation, migration, and invasion of HCC cells. Furthermore, the overexpression of FAT10 in HCC cells led to an increase in PD-L1 expression, resulting in the inhibition of T cell proliferation and the enhancement of HCC cell resistance to T cell-mediated cytotoxicity. Moreover, in vivo experiments utilizing the C57BL/6 mouse model revealed that overexpression of FAT10 effectively suppressed the infiltration of CD8 + GZMB + and CD8 + Ki67 + T cells, as well as reduced serum levels of TNF-α and IFN-γ. Mechanistically, we further identified that FAT10 upregulates PD-L1 expression via activating the PI3K/AKT/mTOR pathway, but not in a ubiquitin-like modification. In conclusion, our findings indicate that FAT10 promotes immune evasion of HCC via upregulating PD-L1 expression, suggesting its potential as a novel target to enhance the efficiency of immunotherapy in HCC.

Interaction between VEGF-A and immune checkpoint targets in triple-negative breast cancer and mechanisms of immune evasion and tumor progression.

1096 Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment triple negative breast cancer (TNBC). However, not all patients with TNBC benefit from the addition of ICIs due to factors such as intrinsic and acquired resistance to ICIs, and complex interplay between tumor and immune cells in the tumor microenvironment (TME). Vascular endothelial growth factor (VEGF) promotes angiogenesis and potentially modulates tumor immune evasion. A phase I clinical trial has shown that a bispecific antibody to VEGF-A and PD-L1 produces encouraging tumor responses in advanced TNBC. In this study, we investigated the interaction between VEGF and various immune gene expression signatures including PD-L1 in a real-world breast cancer patient population. Methods: Comprehensive immune profiling, including the RNA-seq based gene expression assessment of 395 immune-associated genes, was performed on 120 formalin-fixed paraffin-embedded breast cancer samples. PD-L1 expression (Combined Positive Score, CPS ≥ 10%) was measured by immunohistochemistry (IHC; 22C3). Clinicopathologic variables were collected. Statistical associations between quantitative biomarkers, including 28 immune checkpoint genes, were calculated using Pearson correlations (r), and comparisons of quantitative biomarkers between groups were performed using the proportions test. For statistical significance, p<0.05 was required. Results: The study cohort included 29 patients (24.2%) with TNBC and 91 (75.2%) with non-TNBC (including ER+/HER2- and HER2+). Most patients had metastatic tumors (n=92, 76.7%) and invasive ductal carcinoma (n=83, 69.2%). Among the TNBC group, 21 patients had PD-L1 positive tumors (72.4%), defined by CPS ≥ 10.In non-TNBC, VEGF has significant, though weak (r<0.35) correlations with the expression of three checkpoint genes: AKT1 (r=0.35, p=0.00063), ICOS (r=0.34, p=0.00099), and TIM3 (r=0.29, p=0.0061). In TNBC, VEGF has significant, strong (r>0.47) correlations with the expression of three other checkpoint genes: PD-1 (r=0.47, p=0.0094), PD-L1 (r=0.57, p=0.0012), and PIK3CA (r=0.6, p=0.00051) However, in TNBC, VEGF gene expression does not have a statistical association with PD-L1 IHC (CPS ≥/< 10 (p=0.9)). Conclusions: Our findings suggest that there is an interplay between angiogenesis and an immunosuppressive tumor immune microenvironment in TNBC to a greater degree than in non-TNBCs. This supports the notion that angiogenesis mediators such as VEGF-A may enhance the expression of immunosuppressive checkpoint molecules, leading to immune evasion and tumor progression. Combination treatments of ICIs, especially anti-PD-1 therapy, with VEGF antibodies may be promising approaches to enhance the immune responses in TNBC, especially in tumors with CPS<10, where the current frontline treatment is cytotoxic chemotherapy.

Pervasive loss of antigen presentation in solid tumors driven by loss of HLA class I expression.

e14654 Background: Human Leukocyte Antigens (HLA) play a key role in inducing responses to immune checkpoint inhibitor (ICI) therapy. HLA class I (HLA-I) expression is essential for antigen presentation in cancer cells and its loss leads to immune evasion. Expression of HLA-II shows presence of adaptive immune response via antigen presenting cells. To investigate the complex interplay of HLA class I/II in solid tumors, we study the landscape and association of several HLA phenotypes with biomarkers of tumor response and resistance to ICIs in a large pan-cancer cohort. Methods: A real-world cohort of 24,186 solid tumors was assessed by an immune expression profiling assay of 395 genes that were background subtracted, normalized, and ranked yielding a percentile rank value [0-100]. HLA Class I and class II expressions were estimated as average expression of HLA-A, HLA-B, HLA-C genes, and HLA HLA-DP, HLA-DQ, HLA-DR genes, respectively. Both HLA classes were labelled as high (≥66), moderate (≥33 & <66) or low (<33). We studied the distribution of HLA I/II phenotype defined as Ihi/IIhi comprised hot tumors with no loss of HLA-I and Ilo/IIhi defines immune evasion via loss of HLA-I in hot tumors. Ihi/IIlo phenotype comprises less inflamed tumors with high HLA-I expression and Ilo/IIlo comprises of cold tumors. We also performed differential expression of ICI targets including PD-1, PD-L1, LAG-3, TIM3 and expression-based signatures of inflammation and cell proliferation. Results: Loss of HLA-I expression was observed in 44.1% (n= 10669) of all solid tumors with most frequent loss observed in prostate (55%, n=450) cancer. Similarly, loss of HLA-II expression was observed in 34.7% (n=8396) of solid tumors with highest loss observed in neuroendocrine (59%; n=345) cancers. 49% of all tumors presented with four HLA-phenotypes, where 17.9% (n=4332) were characterized by Ilo/IIlo phenotype. Ihi/IIlo was present in 13% (n=3127) of all tumors. Both Ihi/IIhi and Ilo/IIhi phenotypes were significantly (p<0.001) associated with increased tumor inflammation. Other ICI targets such as PD-L1, TIM3, CTLA4 and LAG3 were significantly (p<0.001) overexpressed in this immune evasion phenotype compared to other phenotypes. Conversely, Ilo/IIlo phenotype was significantly associated with cold tumors (p<0.001), hinting at lack of adaptive immune response in these tumors. Conclusions: This study offers insight into pervasive loss of antigen presentation via HLA expression. Concurrent loss of HLA Class I expression with increased class II expression and additional ICI target co-expression is a potential immune escape mechanism in immunologically active solid tumors. Distinct and significant association of these MHC phenotypes with tumor inflammation, checkpoint markers and PD-L1 highlight the potential use of comprehensive immune profiling for further studying combination strategies to correct soft loss of HLA-I and ICI therapies.

Dual analysis of IL-8 in non-small cell lung cancer: A clinical perspective on protein and RNA evaluation via imaging mass cytometry.

e15068 Background: The cytokine Interleukin-8 (IL-8) plays a pivotal role in the tumorigenesis and progression of non-small cell lung cancer (NSCLC), influencing both the tumor microenvironment and immune escape mechanisms. Given its significance, accurately assessing IL-8 levels at the protein and RNA levels could provide valuable insights into its prognostic value and inform therapeutic targeting strategies. This study utilizes imaging mass cytometry (IMC) to conduct a comprehensive evaluation of IL-8 expression in NSCLC, integrating both protein presence and gene expression analysis within the spatial context of the tumor microenvironment. Methods: Our approach leverages the capabilities of IMC to simultaneously detect protein and RNA levels of IL-8 in NSCLC tissue samples. For protein analysis, antibodies tagged with heavy metal isotopes specifically target IL-8, allowing for precise quantification and spatial localization within the tumor. Concurrently, RNA detection is achieved through hybridization probes designed for IL-8 mRNA, enabling the direct observation of gene expression patterns. This method provides a unique opportunity to correlate IL-8's protein abundance with its mRNA expression, offering insights into the regulatory mechanisms at play and their impact on the tumor's behavior and patient outcomes. Results: Preliminary data demonstrate a marked heterogeneity in IL-8 distribution at both the protein and RNA levels, with distinct patterns emerging that relate to tumor aggressiveness and immune infiltration. High IL-8 expression, identified through our integrated IMC approach, correlates with poor prognosis and reduced response to standard therapies, underscoring its potential as a biomarker for NSCLC management. Furthermore, the spatial analysis afforded by IMC highlights the microenvironmental niches where IL-8-mediated interactions could drive tumor progression and immune evasion. Conclusions: By employing IMC for the dual analysis of IL-8 protein and RNA in NSCLC, our study provides a comprehensive view of this cytokine's role in lung cancer pathology. The ability to visualize and quantify IL-8 expression within the spatial context of the tumor microenvironment opens new avenues for understanding its biological impact and for developing targeted therapies. Our findings advocate for the inclusion of IL-8 in the biomarker panel for NSCLC, with potential implications for patient stratification and personalized treatment planning. Future research will focus on expanding these observations to a larger cohort and exploring the therapeutic modulation of IL-8 as a strategy for improving NSCLC outcomes.

Structural and functional characterization of nanobodies that neutralize Omicron variants of SARS-CoV-2.

The Omicron strains of SARS-CoV-2 pose a significant challenge to the development of effective antibody-based treatments as immune evasion has compromised most available immune therapeutics. Therefore, in the 'arms race' with the virus, there is a continuing need to identify new biologics for the prevention or treatment of SARS-CoV-2 infections. Here, we report the isolation of nanobodies that bind to the Omicron BA.1 spike protein by screening nanobody phage display libraries previously generated from llamas immunized with either the Wuhan or Beta spike proteins. The structure and binding properties of three of these nanobodies (A8, H6 and B5-5) have been characterized in detail providing insight into their binding epitopes on the Omicron spike protein. Trimeric versions of H6 and B5-5 neutralized the SARS-CoV-2 variant of concern BA.5 both in vitro and in the hamster model of COVID-19 following nasal administration. Thus, either alone or in combination could serve as starting points for the development of new anti-viral immunotherapeutics.

Therapeutic potential of immune-cold solid tumors through homologous recombination deficiency.

e14585 Background: Genome-wide homologous recombination deficiency (HRD) score is an important parameter to select patients for HRR pathway inhibitors. HRD scores are independent therapeutic predictors unlike tumor mutation burden (TMB), and microsatellite instability (MSI) values to stratify tumors for predicting immunogenicity. Since solid tumors often choose the hallmark of immune evasion to disseminate to distant tissues, their identification and treatment through genomic signatures for immunotherapy is essential. Low TMB and MSI values are often associated with immune evasion and immune cold tumors. For such patients HRD scores can be important determinants to inform on the therapeutic potential of HRR pathway inhibitors and immune checkpoint inhibitors (ICI). In this study, we retrospectively investigated solid tumors with metastatic phenotypes exhibiting microsatellite stable (MSS), MSI-Low and TMB low phenotypes. The presence of HRR pathway deficiency in these patients may lead to chromosomal instabilities and cell surface neo-antigens thereby offering potential therapeutic benefit to PARP inhibitors and ICI. Methods: 53 metastatic cancer patients were retrospectively analysed for genome-wide HRD, TMB and MSI scores based on OncoIndx comprehensive gene panel (CGP). OncoIndx CGP targets 1080 cancer related genes along with 47 HRR genes and 1600 MSI signature sites. HRD, TMB and MSI scores were determined by sequencing the individual sample libraries in pair end mode on Illumina Nextseq platform (depth 5500X). Cutoff scores HRD high (≥50), TMB high (≥10 Mutations/MB), MSI high (≥20). Results: A cohort of 53 solid tumor patients were evaluated retrospectively of which 71.6% (n=38) patients showed metastasis (brain, Popliteal fossa, skeletal, and nodal metastasis). Of these, 9.4% (n=5) patients were detected with MSI-high, 56.6% (n=30) were MSI-Low and 1.8% (n=1) were MSS. 13.2% (n=7) patients were TMB-High, 3.7% (n=2) were TMB intermediate and 41.0% (n=22) were TMB-Low. Most importantly, 41.0% (n=22) patients were both MSI and TMB low thus transforming the tumor suggestively immune-cold. Only 22.7% (n=5) patients showed PD-L1 expression on IHC with scores ranging from TPS: 2% to 20%. In this dominantly immune-cold patient cohort, 40.9% (n=9) patients showed high/intermediate HRD (22.7% high (n=5); 18.18% Intermediate (n=4)). Conclusions: The presence of HRD in 40.9% patients in the dominant immune-cold patients was observed with increased chromosomal instability and cell surface neo-antigens. Thus, HRD could potentially transform tumors to become immune-hot to benefit from PARP inhibitors and ICI.