Electron transport chain capacity expands yellow fever vaccine immunogenicity.

Vaccination has successfully controlled several infectious diseases although better vaccines remain desirable. Host response to vaccination studies have identified correlates of vaccine immunogenicity that could be useful to guide development and selection of future vaccines. However, it remains unclear whether these findings represent mere statistical correlations or reflect functional associations with vaccine immunogenicity. Functional associations, rather than statistical correlates, would offer mechanistic insights into vaccine-induced adaptive immunity. Through a human experimental study to test the immunomodulatory properties of metformin, an anti-diabetic drug, we chanced upon a functional determinant of neutralizing antibodies. Although vaccine viremia is a known correlate of antibody response, we found that in healthy volunteers with no detectable or low yellow fever 17D viremia, metformin-treated volunteers elicited higher neutralizing antibody titers than placebo-treated volunteers. Transcriptional and metabolomic analyses collectively showed that a brief course of metformin, started 3 days prior to YF17D vaccination and stopped at 3 days after vaccination, expanded oxidative phosphorylation and protein translation capacities. These increased capacities directly correlated with YF17D neutralizing antibody titers, with reduced reactive oxygen species response compared to placebo-treated volunteers. Our findings thus demonstrate a functional association between cellular respiration and vaccine-induced humoral immunity and suggest potential approaches to enhancing vaccine immunogenicity.

Pushing the Frontiers of Cancer Research: Highlights from the Frontiers in Cancer Science Conference 2023.

The 15th annual Frontiers in Cancer Science (FCS) conference gathered scientific experts who shared the latest research converging upon several themes of cancer biology. These themes included the dysregulation of metabolism, cell death, and other signaling processes in cancer cells; using patient "omics" datasets and single-cell and spatial approaches to investigate heterogeneity, understand therapy resistance, and identify targets; innovative strategies for inhibiting tumors, including rational drug combinations and improved drug delivery mechanisms; and advances in models that can facilitate screening for cancer vulnerabilities and drug testing. We hope the insights from this meeting will stimulate further progress in the field.

Regorafenib plus nivolumab in unresectable hepatocellular carcinoma: the phase 2 RENOBATE trial.

Regorafenib has anti-tumor activity in patients with unresectable hepatocellular carcinoma (uHCC) with potential immunomodulatory effects, suggesting that its combination with immune checkpoint inhibitor may have clinically meaningful benefits in patients with uHCC. The multicenter, single-arm, phase 2 RENOBATE trial tested regorafenib-nivolumab as front-line treatment for uHCC. Forty-two patients received nivolumab 480 mg every 4 weeks and regorafenib 80 mg daily (3-weeks-on/1-week-off schedule). The primary endpoint was the investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. The secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). ORR per RECIST version 1.1 was 31.0%, meeting the primary endpoint. The most common adverse events were palmar-plantar erythrodysesthesia syndrome (38.1%), alopecia (26.2%) and skin rash (23.8%). Median PFS was 7.38 months. The 1-year OS rate was 80.5%, and the median OS was not reached. Exploratory single-cell RNA sequencing analyses of peripheral blood mononuclear cells showed that long-term responders exhibited T cell receptor repertoire diversification, enrichment of genes representing immunotherapy responsiveness in MKI67+ proliferating CD8+ T cells and a higher probability of M1-directed monocyte polarization. Our data support further clinical development of the regorafenib-nivolumab combination as front-line treatment for uHCC and provide preliminary insights on immune biomarkers of response. ClinicalTrials.gov identifier: NCT04310709 .

Translational research on drug development and biomarker discovery for hepatocellular carcinoma.

Translational research plays a key role in drug development and biomarker discovery for hepatocellular carcinoma (HCC). However, unique challenges exist in this field because of the limited availability of human tumor samples from surgery, the lack of homogenous oncogenic driver mutations, and the paucity of adequate experimental models. In this review, we provide insights into these challenges and review recent advancements, with a particular focus on the two main agents currently used as mainstream therapies for HCC: anti-angiogenic agents and immunotherapy. First, we examine the pre-clinical and clinical studies to highlight the challenges of determining the optimal therapeutic combinations with biologically effective dosage for HCC. Second, we discuss biomarker studies focusing on anti-PD1/anti-PD-L1-based combination therapy. Finally, we discuss the progress made in our collective understanding of tumor immunology and in multi-omics analysis technology, which enhance our understanding of the mechanisms underlying immunotherapy, characterize different patient subgroups, and facilitate the development of novel combination approaches to improve treatment efficacy. In summary, this review provides a comprehensive overview of efforts in translational research aiming at advancing our understanding of and improving the treatment of HCC.

Single cell landscape of functionally cured chronic hepatitis B patients reveals activation of innate and altered CD4-CTL-driven adaptive immunity.

BACKGROUND & AIMS: Hepatitis B surface antigen (HBsAg) loss or functional cure (FC), is considered the desirable therapeutic outcome for chronic hepatitis B (CHB) patients. However, the immune-pathological biomarkers and underlying mechanisms remain unclear. In this study we comprehensively interrogate disease-associated cell states (DACS) identified within intra-hepatic tissue and matched PBMCs from either CHB or FC patients, at the resolution of single cells, to provide novel insights into putative mechanisms underlying FC. METHODS: We combined single cell transcriptomics (scRNA-seq) with multiparametric flow cytometry-based immune phenotyping, and multiplexed immunofluorescence to elucidate the immunopathological cell states associated with CHB vs FC. RESULTS: We find that the intra-hepatic environment of CHB and FC patients displays specific cell identities and molecular signatures that are distinct from those found in matched PBMCs. FC is associated with emergence of an altered adaptive immune response marked by CD4 cytotoxic T lymphocytes (CD4-CTLs), and an activated innate response represented by liver-resident natural killer (LR-NK) cells, specific Kupffer cell (KC) subtypes and marginated neutrophils. Surprisingly, we find that FC patients are also characterized by the presence of MHC class II-expressing hepatocytes and low but persistent levels of cccDNA and pgRNA, which may play an important role in achieving functional cure in HBV patients. CONCLUSIONS: Our study provides conceptually novel insights into the immuno-pathological control of HBV cure, and opens exciting new avenues for clinical management, biomarker discovery and therapeutic interventions. We believe that the discoveries from this study, as it relates to the activation of an innate and altered immune response that may facilitate sustained, low-grade inflammation, may have broader implications in the resolution of chronic viral hepatitis.

CD38 marks the exhausted CD8+ tissue-resident memory T cells in hepatocellular carcinoma.

Introduction: Despite recent advances in immunotherapy for hepatocellular carcinoma (HCC), the overall modest response rate underscores the need for a better understanding of the tumor microenvironment (TME) of HCC. We have previously shown that CD38 is widely expressed on tumor-infiltrating leukocytes (TILs), predominantly on CD3+ T cells and monocytes. However, its specific role in the HCC TME remains unclear. Methods: In this current study, we used cytometry time-of-flight (CyTOF), bulk RNA sequencing on sorted T cells, and single-cell RNA (scRNA) sequencing to interrogate expression of CD38 and its correlation with T cell exhaustion in HCC samples. We also employed multiplex immunohistochemistry (mIHC) for validating our findings. Results: From CyTOF analysis, we compared the immune composition of CD38-expressing leukocytes in TILs, non-tumor tissue-infiltrating leukocytes (NIL), and peripheral blood mononuclear cells (PBMC). We identified CD8+ T cells as the dominant CD38-expressing TILs and found that CD38 expression was significantly higher in CD8+ TRM in TILs than in NILs. Furthermore, through transcriptomic analysis on sorted CD8+ TRM from HCC tumors, we observed a higher expression of CD38 along with T cell exhaustion genes, including PDCD1 and CTLA4, compared to the circulating memory CD8 T cells from PBMC. This was validated by scRNA sequencing that revealed co-expression of CD38 with PDCD1, CTLA4, and ITGAE (CD103) in T cells from HCC tumors. The protein co-expression of CD38 and PD-1 on CD8+ T cells was further demonstrated by mIHC on HCC FFPE tissues, marking CD38 as a T cell co-exhaustion marker in HCC. Lastly, the higher proportions of CD38+PD-1+ CD8+ T cells and CD38+PD-1+ TRM were significantly associated with the higher histopathological grades of HCC, indicating its role in the aggressiveness of the disease. Conclusion: Taken together, the concurrent expression of CD38 with exhaustion markers on CD8+ TRM underpins its role as a key marker of T cell exhaustion and a potential therapeutic target for restoring cytotoxic T cell function in HCC.

RNase2 is a possible trigger of acute-on-chronic inflammation leading to mRNA vaccine-associated cardiac complication.

BACKGROUND: Post-mRNA vaccination-associated cardiac complication is a rare but life-threatening adverse event. Its risk has been well balanced by the benefit of vaccination-induced protection against severe COVID-19. As the rate of severe COVID-19 has consequently declined, future booster vaccination to sustain immunity, especially against infection with new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, may encounter benefit-risk ratios that are less favorable than at the start of the COVID-19 vaccination campaign. Understanding the pathogenesis of rare but severe vaccine-associated adverse events to minimize its risk is thus urgent. METHODS: Here, we report a serendipitous finding of a case of cardiac complication following a third shot of COVID-19 mRNA vaccine. As this case was enrolled in a cohort study, pre-vaccination and pre-symptomatic blood samples were available for genomic and multiplex cytokine analyses. FINDINGS: These analyses revealed the presence of subclinical chronic inflammation, with an elevated expression of RNASE2 at pre-booster baseline as a possible trigger of an acute-on-chronic inflammation that resulted in the cardiac complication. RNASE2 encodes for the ribonuclease RNase2, which cleaves RNA at the 3' side of uridine, which may thus remove the only Toll-like receptor (TLR)-avoidance safety feature of current mRNA vaccines. CONCLUSIONS: These pre-booster and pre-symptomatic gene and cytokine expression data provide unique insights into the possible pathogenesis of vaccine-associated cardiac complication and suggest the incorporation of additional nucleoside modification for an added safety margin. FUNDING: This work was funded by the NMRC Open Fund-Large Collaborative Grant on Integrated Innovations on Infectious Diseases (OFLCG19May-0034).

IFNγ-IL-17+ CD8 T cells contribute to immunosuppression and tumor progression in human hepatocellular carcinoma.

IL-17-producing CD8 (Tc17) T cells have been shown to play an important role in infection and chronic inflammation, however their implications in hepatocellular carcinoma (HCC) remain elusive. In this study, we performed cytometry by time-of-flight (CyTOF) and revealed the distinctive immunological phenotypes of two IFNγ+ and IFNγ- Tc17 subsets that were preferentially enriched in human HCC. Single-cell RNA-sequencing analysis further revealed regulatory circuits governing the different phenotypes of these Tc17 subsets. In particular, we discovered that IFNγ- Tc17 subset demonstrated pro-tumoral characteristics and expressed higher levels of CCL20. This corresponded to increased tumor infiltration of T regulatory cells (Treg) validated by immunohistochemistry in another independent HCC cohort, demonstrating the immunosuppressive functions of IFNγ- Tc17 subset. Most importantly, higher intra-tumoral proportions of IFNγ- Tc17 were associated with poorer prognosis in patients with HCC and this was further validated in The Cancer Genome Atlas (TCGA) HCC cohort. Taken together, this compendium of transcriptomic and proteomic data of Tc17 subsets sheds light on the immunosuppressive phenotypes of IFNγ- Tc17 and its implications in HCC progression.

Intraoperative blood transfusion does not impact overall and recurrence-free survival after curative hepatectomy for hepatocellular carcinoma: A propensity-score-matched and inverse probability of treatment-weighted study.

INTRODUCTION: Our primary objective was to determine if receiving intraoperative blood transfusion was a significant prognostic factor for overall and recurrence-free survival after curative resection of hepatic cellular carcinoma (HCC). METHODOLOGY: Between 2001 and 2018, 1092 patients with histologically proven primary HCC who underwent curative liver resection were retrospectively reviewed. Primary study endpoints were recurrence-free survival (RFS) and overall survival (OS). The main analysis was undertaken using propensity-score matching (PSM) to minimize confounding and selection biases in the comparison of patients with or without transfusion. RESULTS: There were 220 patients who received and 666 patients who did not receive intraoperative blood transfusion. The PSM cohort consisted of 163 pairs of patients. After PSM, the only perioperative outcome that appeared to significantly affect whether patients would receive blood transfusion was median blood loss (p = 0.001). In the PSM cohort, whether patients received blood transfusion was neither associated with OS (p = 0.759) nor RFS (p = 0.830). When the volume of blood transfusion was analyzed as a continuous variable, no significant dose-response relationship between blood transfusion volume and HR for OS and RFS was noted. CONCLUSION: Intraoperative blood transfusion had no significant impact on the survival outcomes in patients who receive curative resection in primary HCC.

A phase I study of an adenoviral vector delivering a MUC1/CD40-ligand fusion protein in patients with advanced adenocarcinoma.

Cancer vaccines as immunotherapy for solid tumours are currently in development with promising results. We report a phase 1 study of Ad-sig-hMUC1/ecdCD40L (NCT02140996), an adenoviral-vector vaccine encoding the tumour-associated antigen MUC1 linked to CD40 ligand, in patients with advanced adenocarcinoma. The primary objective of this study is safety and tolerability. We also study the immunome in vaccinated patients as a secondary outcome. This trial, while not designed to determine clinical efficacy, reports an exploratory endpoint of overall response rate. The study meets its pre-specified primary endpoint demonstrating safety and tolerability in a cohort of 21 patients with advanced adenocarcinomas (breast, lung and ovary). The maximal dose of the vaccine is 1 ×1011 viral particles, with no dose limiting toxicities. All drug related adverse events are of low grades, most commonly injection site reactions in 15 (71%) patients. Using exploratory high-dimensional analyses, we find both quantitative and relational changes in the cancer immunome after vaccination. Our data highlights the utility of high-dimensional analyses in understanding and predicting effective immunotherapy, underscoring the importance of immune competency in cancer prognosis.

Dynamic phenotypic heterogeneity and the evolution of multiple RNA subtypes in hepatocellular carcinoma: the PLANET study.

Intra-tumor heterogeneity (ITH) is a key challenge in cancer treatment, but previous studies have focused mainly on the genomic alterations without exploring phenotypic (transcriptomic and immune) heterogeneity. Using one of the largest prospective surgical cohorts for hepatocellular carcinoma (HCC) with multi-region sampling, we sequenced whole genomes and paired transcriptomes from 67 HCC patients (331 samples). We found that while genomic ITH was rather constant across stages, phenotypic ITH had a very different trajectory and quickly diversified in stage II patients. Most strikingly, 30% of patients were found to contain more than one transcriptomic subtype within a single tumor. Such phenotypic ITH was found to be much more informative in predicting patient survival than genomic ITH and explains the poor efficacy of single-target systemic therapies in HCC. Taken together, we not only revealed an unprecedentedly dynamic landscape of phenotypic heterogeneity in HCC, but also highlighted the importance of studying phenotypic evolution across cancer types.

Uncoupling immune trajectories of response and adverse events from anti-PD-1 immunotherapy in hepatocellular carcinoma.

BACKGROUND & AIMS: While immune checkpoint blockade (ICB) has shown promise in patients with hepatocellular carcinoma (HCC), it is associated with modest response rates and immune-related adverse events (irAEs) are common. In this study, we aimed to decipher immune trajectories and mechanisms of response and/or irAEs in patients with HCC receiving anti-programmed cell death 1 (anti-PD-1) therapy. METHODS: Pre- and on-treatment peripheral blood samples (n = 60) obtained from 32 patients with HCC (Singapore cohort) were analysed by cytometry by time-of-flight and single-cell RNA sequencing, with flow cytometric validation in an independent Korean cohort (n = 29). Mechanistic validation was conducted by bulk RNA sequencing of 20 pre- and on-treatment tumour biopsies and using a murine HCC model treated with different immunotherapeutic combinations. RESULTS: Single-cell analyses identified CXCR3+CD8+ effector memory T (TEM) cells and CD11c+ antigen-presenting cells (APC) as associated with response (p = 0.0004 and 0.0255, respectively), progression-free survival (p = 0.00079 and 0.0015, respectively), and irAEs (p = 0.0034 and 0.0125, respectively) in anti-PD-1-treated patients with HCC. Type-1 conventional dendritic cells were identified as the specific APC associated with response, while 2 immunosuppressive CD14+ myeloid clusters were linked to reduced irAEs. Further analyses of CXCR3+CD8+ TEM cells showed cell-cell interactions specific to response vs. irAEs, from which the anti-PD-1 and anti-TNFR2 combination was harnessed to uncouple these effects, resulting in enhanced response without increased irAEs in a murine HCC model. CONCLUSIONS: This study identifies early predictors of clinical response to anti-PD-1 ICB in patients with HCC and offers mechanistic insights into the immune trajectories of these immune subsets at the interface between response and toxicity. We also propose a new combination immunotherapy for HCC to enhance response without exacerbating irAEs. CLINICAL TRIAL NUMBER: NCT03695952. LAY SUMMARY: Response rates to immune checkpoint blockade (ICB) treatment in hepatocellular carcinoma (HCC) remain modest and adverse events are common. Herein, we identified early predictors of response and gained an in-depth understanding of the immunological mechanisms behind response and adverse events in patients with HCC treated with ICB. We also proposed a new combination immunotherapy for HCC that enhances response without exacerbating adverse events.

Trajectory of immune evasion and cancer progression in hepatocellular carcinoma.

Immune evasion is key to cancer initiation and later at metastasis, but its dynamics at intermediate stages, where potential therapeutic interventions could be applied, is undefined. Here we show, using multi-dimensional analyses of resected tumours, their adjacent non-tumour tissues and peripheral blood, that extensive immune remodelling takes place in patients with stage I to III hepatocellular carcinoma (HCC). We demonstrate the depletion of anti-tumoural immune subsets and accumulation of immunosuppressive or exhausted subsets along with reduced tumour infiltration of CD8 T cells peaking at stage II tumours. Corresponding transcriptomic modification occur in the genes related to antigen presentation, immune responses, and chemotaxis. The progressive immune evasion is validated in a murine model of HCC. Our results show evidence of ongoing tumour-immune co-evolution during HCC progression and offer insights into potential interventions to reverse, prevent or limit the progression of the disease.

Hypoxia-driven immunosuppression by Treg and type-2 conventional dendritic cells in HCC.

BACKGROUND AND AIMS: Hypoxia is one of the central players in shaping the immune context of the tumor microenvironment (TME). However, the complex interplay between immune cell infiltrates within the hypoxic TME of HCC remains to be elucidated. APPROACH AND RESULTS: We analyzed the immune landscapes of hypoxia-low and hypoxia-high tumor regions using cytometry by time of light, immunohistochemistry, and transcriptomic analyses. The mechanisms of immunosuppression in immune subsets of interest were further explored using in vitro hypoxia assays. Regulatory T cells (Tregs) and a number of immunosuppressive myeloid subsets, including M2 macrophages and human leukocyte antigen-DR isotype (HLA-DRlo ) type 2 conventional dendritic cell (cDC2), were found to be significantly enriched in hypoxia-high tumor regions. On the other hand, the abundance of active granzyme Bhi PD-1lo CD8+ T cells in hypoxia-low tumor regions implied a relatively active immune landscape compared with hypoxia-high regions. The up-regulation of cancer-associated genes in the tumor tissues and immunosuppressive genes in the tumor-infiltrating leukocytes supported a highly pro-tumorigenic network in hypoxic HCC. Chemokine genes such as CCL20 (C-C motif chemokine ligand 20) and CXCL5 (C-X-C motif chemokine ligand 5) were associated with recruitment of both Tregs and HLA-DRlo cDC2 to hypoxia-high microenvironments. The interaction between Tregs and cDC2 under a hypoxic TME resulted in a loss of antigen-presenting HLA-DR on cDC2. CONCLUSIONS: We uncovered the unique immunosuppressive landscapes and identified key immune subsets enriched in hypoxic HCC. In particular, we identified a potential Treg-mediated immunosuppression through interaction with a cDC2 subset in HCC that could be exploited for immunotherapies.

Effect of age on the short- and long-term outcomes of patients undergoing curative liver resection for HCC.

BACKGROUND: Few studies have evaluated the outcomes of curative liver resection (LR) in octogenarian patients, analysed cancer-specific survival (CSS) with HCC-related death or explored the age-varying effect of HCC-related death in elderly patients undergoing LR. We aim to determine the effect of age on the short and long-term outcomes of LR for HCC. METHODOLOGY: Between 2000 and 2018, 1,092 patients with primary HCC who underwent LR with curative intent were retrospectively reviewed. The log-rank test and Gray's test were used to assess the equality of survivor functions and competing risk-adjusted cumulative incidence functions between patients in the three age categories respectively. Regression adjustment was used to control for confounding bias via a Principal Component Analysis. Quantile, Firth logistic, Cox, and Fine-Gray competing risk regression were used to analyse continuous, binary, time-to-event, and cause-specific survival respectively. Restricted cubic splines were used to illustrate the dose-effect relationship between age and patient outcomes. RESULTS: The study comprised of 764 young patients (<70 years), 278 septuagenarians (70-79 years old) and 50 octogenarians (≥80 years). Compared to young patients, octogenarians had significantly lower 5-year OS(62.1% vs 37.7%, p < 0.001). However, there was no significant difference in 1-year RFS(73.1% vs 67.0%, p = 0.774) or 5-year CSS (5.4% vs 15.2%, p = 0.674). Every 10-year increase in age was significantly associated with an increase length of stay (p < 0.001), postoperative complications (p = 0.004) and poorer OS(p = 0.018) but not significantly associated with major complications (p = 0.279), CSS(p = 0.338) or RFS(p = 0.941). CONCLUSION: Age by itself was associated with OS after LR for HCC but was not a significant risk factor for HCC-related death.

Human antibody C10 neutralizes by diminishing Zika but enhancing dengue virus dynamics.

The human monoclonal antibody (HmAb) C10 potently cross-neutralizes Zika virus (ZIKV) and dengue virus. Analysis of antibody fragment (Fab) C10 interactions with ZIKV and dengue virus serotype 2 (DENV2) particles by cryoelectron microscopy (cryo-EM) and amide hydrogen/deuterium exchange mass spectrometry (HDXMS) shows that Fab C10 binding decreases overall ZIKV particle dynamics, whereas with DENV2, the same Fab causes increased dynamics. Testing of different Fab C10:DENV2 E protein molar ratios revealed that, at higher Fab ratios, especially at saturated concentrations, the Fab enhanced viral dynamics (detected by HDXMS), and observation under cryo-EM showed increased numbers of distorted particles. Our results suggest that Fab C10 stabilizes ZIKV but that with DENV2 particles, high Fab C10 occupancy promotes E protein dimer conformational changes leading to overall increased particle dynamics and distortion of the viral surface. This is the first instance of a broadly neutralizing antibody eliciting virus-specific increases in whole virus particle dynamics.

Immune implication of an autophagy-related prognostic signature in uveal melanoma.

Uveal Melanoma (UM) is a rare cancer deriving from melanocytes within the uvea. It has a high rate of metastasis, especially to the liver, and a poor prognosis thereafter. Autophagy, an intracellular programmed digestive process, has been associated with the development and progression of cancers, with controversial pro- and anti-tumour roles. Although previous studies have been conducted on autophagy-related genes (ARGs) in various cancer types, its role in UM requires a deeper understanding for improved diagnosis and development of novel therapeutics. In the present study, Zheng et al. used univariate Cox regression followed by least absolute shrinkage and selection operator (Lasso) regression to identify a robust 9-ARG signature prognostic of survival in a total of 230 patients with UM. The authors used the Cancer Genome Atlas (TCGA) UM cohort as a training cohort (n=80) to identify the signature and validated it in another four independent cohorts of 150 UM patients from the Gene Expression Omnibus (GEO) repository (GSE22138, GSE27831, GSE44295 and GSE84976). This 9-ARG signature was also significantly associated with the enrichment of cancer hallmarks, including angiogenesis, IL6-KJAK-STAT3 signalling, reactive oxygen species pathway and oxidative phosphorylation. More importantly, this signature is associated with immune-related functional pathways and immune cell infiltration. Thus, this 9-ARG signature predicts prognosis and provides deeper insights into the immune mechanisms in UM, with potential implications for future immunotherapy.