Functional tumor specific CD8 + T cells in spleen express a high level of PD-1

An exploratory clinical study of β-glucan combined with camrelizumab and SOX chemotherapy as first-line treatment for advanced gastric adenocarcinoma

Background

β-glucan has been reported to be a potential natural immune modulator for tumor growth inhibition. We aimed to evaluate the efficacy and safety of β-glucan plus immunotherapy and chemotherapy in the first-line treatment of advanced gastric adenocarcinoma.

Methods

This is a phase IB, prospective, single-arm, investigator-initiated trail. Advanced gastric adenocarcinoma patients received β-glucan, camrelizumab, oxaliplatin, oral S-1 every 3 weeks. The curative effect was evaluated every 2 cycles. The primary endpoints were objective response rate (ORR) and safety, with secondary endpoints were median progression-free survival (mPFS) and median overall survival (mOS). The exploratory endpoint explored biomarkers of response to treatment efficacy.

Results

A total of 30 patients had been enrolled, including 20 (66.7%) males and all patients with an ECOG PS score of ≥1. The ORR was 60%, the mPFS was 10.4 months (95% confidence interval [CI], 9.52-11.27), the mOS was 14.0 months (95% CI, 11.09-16.91). A total of 19 patients (63.3%) had TRAEs, with 9 patients (30%) with grade ≥ 3. The most common TRAEs were nausea (53.3%). After 2 cycles of treatment, the levels of IL-2, IFN-γ and CD4+ T cells significantly increased (P < 0.05). Furthermore, biomarker analysis indicated that patient with better response and longer OS exhibited lower GZMA expression at baseline serum.

Conclusions

This preliminary study demonstrates that β-glucan plus camrelizumab and SOX chemotherapy offers favorable efficacy and a manageable safety profile in patients with advanced gastric adenocarcinoma, and further studies are needed to verify its efficacy and safety.

Clinical Trial Registration

Chinese Clinical Trials Registry, identifier ChiCTR2100044088.

Immunomodulatory Synthetic Glycocluster Molecule Prevents Melanoma Growth In Vivo

Triacedimannose (TADM) is a synthetic trivalent acetylated glycocluster and a transmembrane macrophage activator independent of the mannose receptor. TADM induces Th1-type immune responses and suppresses Th2-type cytokines in acute and chronic allergic inflammation models in vivo. We, therefore, wanted to test whether TADM could also facilitate anti-tumour tissue responses similar to what has been observed for the immune checkpoint inhibitors, such as anti-PD-1 and anti-CTLA-4. A syngeneic mouse melanoma model was selected since metastatic melanoma has been successfully targeted by checkpoint inhibitors in the clinic. TADM inhibited the growth of B16 mouse melanoma tumours at levels comparable to an anti-PD-1 antibody. TADM-treated tumours encompassed significantly more apoptotic cells as measured by TUNEL staining, and interferon-gamma (IFN-γ) expression was increased in the spleens of TADM-treated mice compared to untreated controls. TADM-treated mice also demonstrated increased Ly6 C low monocytes and neutrophils in the spleens. However, TADM-treated tumours showed no discernible differences in infiltrating immune cells. TADM can alone suppress the growth of melanoma tumours. TADM likely activates M1 type macrophages, type N1 neutrophils, and CD8+ and Th1 T cells, suppressing the type 2 immune response milieu of melanoma tumour with a strong type 1 immune response.

Nucleic acid-based vaccine for ovarian cancer cells; bench to bedside

Ovarian cancer continues to be a difficult medical issue that affects millions of individuals worldwide. Important platforms for cancer immunotherapy include checkpoint inhibitors, chimeric antigen receptor T cells, bispecific antibodies, cancer vaccines, and other cell-based treatments. To avoid numerous infectious illnesses, conventional vaccinations based on synthetic peptides, recombinant subunit vaccines, and live attenuated and inactivated pathogens are frequently utilized. Vaccine manufacturing processes, however, are not entirely safe and carry a significant danger of contaminating living microorganisms. As a result, the creation of substitute vaccinations is required for both viral and noninfectious illnesses, including cancer. Recently, there has been testing of nucleic acid vaccines, or NAVs, as a cancer therapeutic. Tumor antigens (TAs) are genetically encoded by DNA and mRNA vaccines, which the host uses to trigger immune responses against ovarian cancer cells that exhibit the TAs. Despite being straightforward, safe, and easy to produce, NAVs are not currently thought to be an ideal replacement for peptide vaccines. Some obstacles to this strategy include selecting the appropriate therapeutic agents (TAs), inadequate immunogenicity, and the immunosuppressive characteristic of ovarian cancer. We focus on strategies that have been employed to increase NAVs' effectiveness in the fight against ovarian cancer in this review.

Relationship of FDG Uptake of the Reticuloendothelial System with Tumor Immune Microenvironment and Prognosis in Patients with Gastric Cancer

2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake of the reticuloendothelial system, including the bone marrow (BM) and spleen, on positron emission tomography/computed tomography (PET/CT) has been shown to be a significant prognostic factor in diverse malignancies. However, the relationship between FDG uptake of the BM and spleen and histopathological findings, including the tumor immune microenvironment, has not been fully evaluated. This study aimed to investigate the relationship of FDG uptake in the BM and spleen with histopathological findings and recurrence-free survival (RFS) in patients with gastric cancer. Seventy patients with gastric cancer who underwent pre-operative FDG PET/CT and subsequent curative surgery were retrospectively enrolled. On image analysis, the BM-to-liver uptake ratio (BLR) and spleen-to-liver uptake ratio (SLR) were measured from PET/CT images, and on immunohistochemical analysis, the densities of immune cell infiltration in the tumor tissue were graded. The BLR and SLR showed significant positive correlations with the grades of CD163 cell and CD8 cell infiltration in the tumor tissue, respectively (p < 0.05). In multivariate survival analysis, both BLR and SLR were significant predictors of RFS (p < 0.05). FDG uptake in the BM and spleen might be potential imaging biomarkers for evaluating tumor immune microenvironment conditions and predicting RFS in patients with gastric cancer.

IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8+ T cells in vivo

The induction of antitumor effector T cells in the tumor microenvironment is a crucial event for cancer immunotherapy. Neurokinin receptor 2 (NK2R), a G protein-coupled receptor for neurokinin A (NKA), regulates diverse physiological functions. However, the precise role of NKA-NK2R signaling in antitumor immunity is unclear. Here, we found that an IFN-γ-STAT1 cascade augmented NK2R expression in CD8⁺ T cells, and NK2R-mediated NKA signaling was involved in inducing antitumor effector T cells in vivo. The administration of a synthetic analog of double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C), into a liver cancer mouse model induced type I and type II IFNs and significantly suppressed the tumorigenesis of Hepa1-6 liver cancer cells in a STAT1-dependent manner. The reduction in tumor growth was diminished by the depletion of CD8⁺ T cells. IFN-γ stimulation significantly induced NK2R and tachykinin precursor 1 (encodes NKA) gene expression in CD8⁺ T cells. NKA stimulation combined with anti-CD3 monoclonal antibody (mAb) treatment significantly augmented IFN-γ and granzyme B production by CD8⁺ T cells compared with the anti-CD3 mAb alone in vitro. ERK1/2 phosphorylation and IκBα degradation in activated CD8⁺ T cells were suppressed under NK2R deficiency. Finally, we confirmed that tumor growth was significantly increased in NK2R-deficient mice compared with that in wild-type mice, and the antitumor effects of poly I:C were abolished by NK2R absence. These findings suggest that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector T cells in the tumor microenvironment, which contributes to the suppression of cancer cell tumorigenesis in vivo. In this study, we revealed that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8⁺ T cells in the tumor microenvironment, which contributes to suppressing the tumorigenesis of liver cancer cells in vivo.

Potential biomarkers: Identifying powerful tumor specific T cells in adoptive cellular therapy

Tumor-specific T cells (TSTs) are essential components for the success of personalized tumor-infiltrating lymphocyte (TIL)-based adoptive cellular therapy (ACT). Therefore, the selection of a common biomarker for screening TSTs in different tumor types, followed by ex vivo expansion to clinical number levels can generate the greatest therapeutic effect. However, studies on shared biomarkers for TSTs have not been realized yet. The present review summarizes the similarities and differences of a number of biomarkers for TSTs in several tumor types studied in the last 5 years, and the advantages of combining biomarkers. In addition, the review discusses the possible shortcomings of current biomarkers and highlights strategies to identify TSTs accurately using intercellular interactions. Finally, the development of TSTs in personalized TIL-based ACT for broader clinical applications is explored.

β-Glucan Combined With PD-1/PD-L1 Checkpoint Blockade for Immunotherapy in Patients With Advanced Cancer

Programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) checkpoint blocking antibodies have been shown to be a powerful immune checkpoint blockade (ICB) therapy for patients with cancer. However, patients quickly develop resistance to immunotherapy. β-glucan, an immune adjuvant, has been found to stimulate innate and adaptive immune responses. In this study, we assessed the use of whole glucan particle (WGP) β-glucan in combination with PD-1/PD-L1–blocking antibodies to slow down the resistance to immunotherapy. Results from a tumor mouse model demonstrated that administration of WGP β-glucan plus PD-1/PD-L1–blocking antibodies led to increased recruitment of immune-associated cells, improved regulation of the balance between T-cell activation and immune tolerance, and delayed tumor progression. This combination therapy was also found to improve progression-free survival in patients with advanced cancer who had previously discontinued anti-PD-1/PD-L1 because of disease progression. These findings suggest that β-glucan could be used as an immune adjuvant to reverse anti-PD-1/PD-L1 resistance by regulating the immune system.

Intermittent administration of tacrolimus enhances anti-tumor immunity in melanoma-bearing mice

One key reason for T cell exhaustion is continuous antigen exposure. Early exhausted T cells can reverse exhaustion and differentiate into fully functional memory T cells if removed from persisting antigen stimulation. Therefore, this study viewed T cell exhaustion as an over-activation status induced by chronic antigen stimuli. This study hypothesized that blocking TCR signal intermittently to terminate over-activation signal can defer the developmental process of T cell exhaustion. In this study, melanoma-bearing mice were treated with tacrolimus (FK506) every five days. The tumor size and tumor-infiltrating lymphocytes (TILs) were analyzed. We found that intermittent administration of tacrolimus significantly inhibited tumor growth, and this effect was mediated by CD8+T cells. Intermittent tacrolimus treatment facilitated the infiltration of CD8+TILs. RNA-seq and quantitative RT-PCR of sorted CD8+TILs showed the expression of Nr4a1 (an exhaustion-related transcription factor) and Ctla4 (a T cell inhibitory receptor) was remarkably downregulated. These results indicated that intermittently blocking TCR signal by tacrolimus can promote anti-tumor immunity and inhibit the tumor growth in melanoma-bearing mice, inhibiting the transcription of several exhaustion-related genes, such as Nr4a1 and Ctla4.

COVID-19: The Immune Responses and Clinical Therapy Candidates

The pandemic of coronavirus disease 2019 (COVID-19), with rising numbers of patients worldwide, presents an urgent need for effective treatments. To date, there are no therapies or vaccines that are proven to be effective against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several potential candidates or repurposed drugs are under investigation, including drugs that inhibit SARS-CoV-2 replication and block infection. The most promising therapy to date is remdesivir, which is US Food and Drug Administration (FDA) approved for emergency use in adults and children hospitalized with severe suspected or laboratory-confirmed COVID-19. Herein we summarize the general features of SARS-CoV-2's molecular and immune pathogenesis and discuss available pharmacological strategies, based on our present understanding of SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV) infections. Finally, we outline clinical trials currently in progress to investigate the efficacy of potential therapies for COVID-19.