B19-VLPs as an effective delivery system for tumour antigens to induce humoral and cellular immune responses against triple negative breast cancer
Cancer immunotherapy is emerging as a viable treatment option for several types of cancer. Active immunotherapy aims for the induction of specific antitumor immune responses; this goal requires strategies capable of increasing the immunogenicity of tumour antigens. Parvovirus B19 virus-like particles (B19-VLPs) formed of VP2 protein had been shown to be an effective multi-neoepitope delivery system capable of inducing specific cellular responses towards coupled antigens and reducing tumour growth and lung metastases in triple negative breast cancer mouse model. These findings encouraged us to further characterise these VP2 B19-VLPs by testing their capacity to simultaneously induce cellular and humoral responses towards other tumour-associated antigens, as this had not yet been evaluated. Here, we designed and evaluated in the 4T1 breast cancer model the prophylactic and therapeutic effect of VP2 B19-VLPs decorated with cellular (P53) and humoral (MUC1) epitopes. Balb/c mice were immunised with chimeric VLPs, vehicle, or VLPs plus adjuvant. Tumour establishment and growth, lung metastasis, and cellular and humoral immune responses were evaluated. The prophylactic administration of chimeric VLPs without adjuvant prevented the establishment of the tumour, while by therapeutic administration, chimeric VLPs induced smaller tumour growth and decreased the number of metastases in the lung compared to wild-type VLPs. Chimeric VLPs induced high antibody titres towards the MUC1 epitope, as well as specific cellular responses towards P53 epitopes in lymph nodes local to the tumour. Our results reinforce and extend the utility of VP2 B19-VLPs as an encouraging tumour antigen delivery system in cancer immunotherapy able to improve tumour immunity in TNBC by inducing cellular and humoral immune responses.
Comparability study of monocyte derived dendritic cells, primary monocytes, and THP1 cells for innate immune responses
Immunogenicity is one major challenge to the successful development of biotherapeutics because it could adversely affect PK/PD, safety, and efficacy. Preclinical immunogenicity risk assessment strategies and assays have been developed and implemented to screen and optimize discovery molecules. Internalization by antigen presenting cells (APC) and innate immune activation are initial prerequisite steps in eliciting immune responses to biotherapeutics. Dendritic cells (DC)- and monocyte-based assays are employed to interrogate such risks, and their value has been well documented in the literature. However, these assays have limited throughput, exhibit higher variability, and entail lengthy and complex procedures as they are based on primary cells such as peripheral blood mononuclear cells (PBMC) from individual donors. Herein, we investigated THP1 cells as surrogate cells to study APC internalization and innate immune activation. Comparability studies showed that THP1 cells could resemble innate immune responses of monocyte-derived DC and primary CD14+ monocytes using a panel of therapeutic antibodies. In addition, an automated high throughput THP1 internalization assay was qualified to enable risk assessment at pre_lead stages. The results demonstrated that THP1 cells can be utilized to assess immunogenicity risk in a high throughput manner.
Antitumor CD8 T cell responses in glioma patients are effectively suppressed by T follicular regulatory cells
Regulatory T (Treg) cells are thought to contribute to tumor pathogenesis by suppressing tumor immunosurveillance and antitumor immunity. T follicular regulatory (Tfr) cells are a recently characterized Treg subset that expresses both the Treg transcription factor (TF) Foxp3 and the T follicular helper (Tfh) TF Bcl-6. The role of Tfr cells in glioma patients remains unclear. In this study, we found that the level of Tfr cells, identified as Foxp3(+)Bcl-6(+) CD4 T cells, was significantly elevated in tumor-infiltrating CD4 T cells from resected glioma tumors. Both Tfr cells and Treg cells significantly suppressed the proliferation and the cytotoxic capacity of CD8 T cells toward glioma tumor cells, and the suppression was positively associated with the proportion of Tfr cells and Treg cells, respectively. Tfr and Treg cells from glioma tumor samples demonstrated higher suppression potency than those from healthy blood samples and glioma blood samples. Interestingly, canonical CXCR5(-) Treg cells could suppress both CXCR5(+) and CXCR5(-) CD8 T cells, albeit with stronger potency toward CXCR5(-) CD8 T cells. However, Tfr cells presented much higher suppression potency toward CXCR5(+) CD8 T cells, whereas CXCR5(+) CD8 T cells are a potent CD8 T cell subset previously described to have antiviral and antitumor roles. Overall, these data indicate that Tfr cells are enriched in glioma tumors and have suppressive capacity toward CD8 T cell-mediated effector functions.
Multifunctional carbon monoxide nanogenerator as immunogenic cell death drugs with enhanced antitumor immunity and antimetastatic effect
The limited effect of immune checkpoint blockade (ICB) immunotherapy is subjected to the immuno-suppressive tumor microenvironment (TME). It is still a challenge to reverse the immune-suppressive state in clinical cancer therapy. Immunogenic cell death (ICD) is a way for inducing the therapeutical tumor immune system. In this work, carbon monoxide (CO) gas therapy is used to boost antitumor immunity for tumor control, metastasis and recurrence prevention. Briefly, CO(2)-g-C(3)N(4)-Au@ZIF-8@F127 (CCAZF) is proposed to integrate gas therapy and immunotherapy into a photocatalytic nanogenerator for overcoming the limitations of monotherapy. CCAZF exhibits a highly effective light-controllable release behavior of CO, which gradually aggravates the oxidative stress in tumor cells to induce ICD. With the induction of ICD, CO therapy enhances immune responses and enables efficient immune cells activated. When combined with ICB, CCAZF displays an enhanced immune effect, which mediates the regression of primary and distal tumors. This strategy of in-situ photocatalytic CO therapy furthest avoids the toxicity from CO leakage and provides a new method to design novel ICD inducers.
Elevated Flt3L Predicts Long-Term Survival in Patients with High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms
BACKGROUND: The clinical management of high-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) is challenging due to disease heterogeneity, illustrating the need for reliable biomarkers facilitating patient stratification and guiding treatment decisions. FMS-like tyrosine kinase 3 ligand (Flt3L) is emerging as a prognostic or predictive surrogate marker of host tumoral immune response and might enable the stratification of patients with otherwise comparable tumor features. METHODS: We evaluated Flt3L gene expression in tumor tissue as well as circulating Flt3L levels as potential biomarkers in a cohort of 54 patients with GEP-NEN. RESULTS: We detected a prominent induction of Flt3L gene expression in individual G2 and G3 NEN, but not in G1 neuroendocrine tumors (NET). Flt3L mRNA expression levels in tumor tissue predicted the disease-related survival of patients with highly proliferative G2 and G3 NEN more accurately than the conventional criteria of grading or NEC/NET differentiation. High level Flt3L mRNA expression was associated with the increased expression of genes related to immunogenic cell death, lymphocyte effector function and dendritic cell maturation, suggesting a less tolerogenic (more proinflammatory) phenotype of tumors with Flt3L induction. Importantly, circulating levels of Flt3L were also elevated in high grade NEN and correlated with patients' progression-free and disease-related survival, thereby reflecting the results observed in tumor tissue. CONCLUSIONS: We propose Flt3L as a prognostic biomarker for high grade GEP-NEN, harnessing its potential as a marker of an inflammatory tumor microenvironment. Flt3L measurements in serum, which can be easily be incorporated into clinical routine, should be further evaluated to guide patient stratification and treatment decisions.
Cytolytic Activity of CAR T Cells and Maintenance of Their CD4+ Subset Is Critical for Optimal Antitumor Activity in Preclinical Solid Tumor Models
Correlative studies of clinical studies for hematological malignancies have implicated that less differentiated, CD8+-dominant CAR T cell products have greater antitumor activity. Here, we have investigated whether the differentiation status of CAR T cell products affects their antitumor activity in preclinical models of solid tumors. We explored if different activation/expansion protocols, as well as different co-stimulatory domains in the CAR construct, influence the short- and long-term efficacy of CAR T cells against HER2-positive tumors. We generated T cell products that range from the most differentiated (CD28.z; OKT3-antiCD28/RPMI expansion) to the least differentiated (41BB.z; OKT3-RetroNectin/LymphoONE expansion), as judged by cell surface expression of the differentiation markers CCR7 and CD45RA. While the effect of differentiation status was variable with regard to antigen-specific cytokine production, the most differentiated CD28.z CAR T cell products, which were enriched in effector memory T cells, had the greatest target-specific cytolytic activity in vitro. These products also had a greater proliferative capacity and maintained CD4+ T cells upon repeated stimulation in vitro. In vivo, differentiated CD28.z CAR T cells also had the greatest antitumor activity, resulting in complete response. Our results highlight that it is critical to optimize CAR T cell production and that optimal product characteristics might depend on the targeted antigen and/or cancer.
Efficacy and safety of BNT162b2 vaccination in patients with solid cancer receiving anticancer therapy - a single centre prospective study
AIM: Patients with cancer are at an increased risk for severe coronavirus disease of 2019, thus data on the safety and efficacy of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines are essential. We conducted this prospective study of patients with cancer vaccinated with BNT162b2 and monitored for antibody response and safety. The aim was to evaluate the rate of seropositivity and define predictors for non-reactive immune response. Furthermore, we evaluated the frequency and the severity of adverse events. METHODS: The study included patients with solid tumours undergoing anticancer treatment and immunocompetent health-care workers serving as controls. Serum titres of the receptor-binding domain (RBD) immunoglobulin G (IgG) and neutralising antibodies were measured 2-4 weeks after each vaccine dose. RESULTS: The analysis included 129 patients, of which 70.5% patients were metastatic. Patients were treated with chemotherapy (55%), immunotherapy (34.1%), biological agents (24.8%), hormonal treatment (8.5%) and radiotherapy (4.6%), that were given either alone or in combinations. The seropositivity rate among patients with cancer and controls was 32.4% versus 59.8% (p < 0.0001) after the first dose and 84.1% versus 98.9% (p < 0.0001) after the second dose, respectively. Median RBD-IgG titre was lower among patients than controls (p < 0.0001). Patients who were seronegative after the second dose had significantly more comorbidities than that with patients with seropositivity (77.8% vs 41.1%, respectively, p = 0.0042). CONCLUSION: Adequate antibody response after BNT162b2 vaccination was achieved after two doses but not after one dose, in patients with cancer vaccinated during anticancer therapy.
Comprehensive analysis of the cancer driver genes in breast cancer demonstrates their roles in cancer prognosis and tumor microenvironment
BACKGROUND: Breast cancer is the most common malignancy in women. Cancer driver gene-mediated alterations in the tumor microenvironment are critical factors affecting the biological behavior of breast cancer. The purpose of this study was to identify the expression characteristics and prognostic value of cancer driver genes in breast cancer. METHODS: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets are used as the training and test sets. Classified according to cancer and paracancerous tissues, we identified differentially expressed cancer driver genes. We further screened prognosis-associated genes, and candidate genes were submitted for the construction of a risk signature. Functional enrichment analysis and transcriptional regulatory networks were performed to search for possible mechanisms by which cancer driver genes affect breast cancer prognosis. RESULTS: We identified more than 200 differentially expressed driver genes and 27 prognosis-related genes. High-risk group patients had a lower survival rate compared to the low-risk group (P<0.05), and risk signature showed high specificity and sensitivity in predicting the patient prognosis (AUC 0.790). Multivariate regression analysis suggested that risk scores can independently predict patient prognosis. Further, we found differences in PD-1 expression, immune score, and stromal score among different risk groups. CONCLUSION: Our study confirms the critical prognosis role of cancer driver genes in breast cancer. The cancer driver gene risk signature may provide a novel biomarker for clinical treatment strategy and survival prediction of breast cancer.
The CD112R/CD112 axis: a breakthrough in cancer immunotherapy
The recent discovery of immune checkpoint inhibitors is a significant milestone in cancer immunotherapy research. However, some patients with primary or adaptive drug resistance might not benefit from the overall therapeutic potential of immunotherapy in oncology. Thus, it is becoming increasingly critical for oncologists to explore the availability of new immune checkpoint inhibitors. An emerging co-inhibitory receptor, CD112R (also called PVRIG), is most commonly expressed on natural killer (NK) and T cells. It binds to its ligand (CD112 or PVRL2/nectin-2) and inhibits the strength with which T cells and NK cells respond to cancer. Therefore, CD112R is being presented as a new immune checkpoint inhibitor with high potential in cancer immunotherapy. CD112 is easily detectable on antigen-presenting or tumor cells, and its high level of expression has been linked with tumor progression and poor outcomes in most cancer patients. This review explores the molecular and functional relationship between CD112R, TIGIT, CD96, and CD226 in T cell responses. In addition, this review comprehensively discusses the recent developments of CD112R/CD112 immune checkpoints in cancer immunotherapy and prognosis.
A Polysaccharide From the Whole Plant of Plantago asiatica L. Enhances the Antitumor Activity of Dendritic Cell-Based Immunotherapy Against Breast Cancer
Dendritic cells (DCs) are the most potent professional antigen-presenting cells (APCs) that mediate T-cell immune responses. Breast cancer is one of the most commonly diagnosed diseases and its mortality rate is higher than any other cancer in both humans and canines. Plantain polysaccharide (PLP), extracted from the whole plant of Plantago asiatica L., could promote the maturation of DCs. In this research, we found that PLP could upregulate the maturation of DCs both in vitro and in vivo. PLP-activated DCs could stimulate lymphocytes' proliferation and differentiate naive T cells into cytotoxic T cells. Tumor antigen-specific lymphocyte responses were enhanced by PLP and CIPp canine breast tumor cells lysate-pulsed DCs, and PLP and CIPp-cell-lysate jointly stimulated DCs cocultured with lymphocytes having the great cytotoxicity on CIPp cells. In the 4T1 murine breast tumor model, PLP could control the size of breast tumors and improve immunity by recruiting DCs, macrophages, and CD4(+) and CD8(+) T cells in the tumor microenvironment. These results indicated that PLP could achieve immunotherapeutic effects and improve immunity in the breast tumor model.