Enhancing the Efficacy of Tumor Vaccines Based on Immune Evasion Mechanisms

A scaffold vaccine to promote tumor antigen cross-presentation via sustained toll-like receptor-2 (TLR2) activation

Cancer vaccination holds great promise for cancer treatment, but its effectiveness is hindered by suboptimal activation of CD8+ cytotoxic T lymphocytes, which are potent effectors to mediate anti-tumor immune responses. A possible solution is to switch antigen-presenting cells to present tumor antigens via the major histocompatibility complex class I (MHC-I) to CD8+ T cells - a process known as cross-presentation. To achieve this goal, we develop a three-dimensional (3D) scaffold vaccine to promote antigen cross-presentation by persisted toll-like receptor-2 (TLR2) activation after one injection. This vaccine comprises polysaccharide frameworks that "hook" TLR2 agonist (acGM) via tunable hydrophobic interactions and forms a 3D macroporous scaffold via click chemistry upon subcutaneous injection. Its retention-and-release of acGM enables sustained TLR2 activation in abundantly recruited dendritic cells in situ, inducing intracellular production of reactive oxygen species (ROS) in optimal kinetics that crucially promotes efficient antigen cross-presentation. The scaffold loaded with model antigen ovalbumin (OVA) or tumor specific antigen can generate potent immune responses against lung metastasis in B16-OVA-innoculated wild-type mice or spontaneous colorectal cancer in transgenic ApcMin/+ mice, respectively. Notably, it requires neither additional adjuvants nor external stimulation to function and can be adjusted to accommodate different antigens. The developed scaffold vaccine may represent a new, competent tool for next-generation personalized cancer vaccination.

Trichostatin A-modified vaccine provides superior protection against ovarian cancer formation and development

More attention has been paid to immunotherapy for ovarian cancer and the development of tumor vaccines. We developed a trichostatin A (TSA)-modified tumor vaccine with potent immunomodulating activities that can inhibit the growth of ovarian cancer in rats and stimulate immune cell response in vivo. TSA-treated Nutu-19 cells inactivated by X-ray radiation were used as a tumor vaccine in rat ovarian cancer models. Prophylactic and therapeutic experiments were performed with TSA-modified tumor vaccine in rats. Flow cytometry and ELISpot assays were conducted to assess immune response. Immune cell expression in the spleen and thymus were detected by immunohistochemical staining. GM-CSF, IL-7, IL-17, LIF, LIX, KC, MCP-1, MIP-2, M-CSF, IP-10/CXCL10, MIG/CXCL9, RANTES, IL-4, IFN-γ, and VEGF expressions were detected with Milliplex Map Magnetic Bead Panel immunoassay. TSA vaccination in therapeutic and prophylactic models could effectively stimulate innate immunity and boost the adaptive humoral and cell-mediated immune responses to inhibit the growth and tumorigenesis of ovarian cancer. This vaccine stimulated the thymus into reactivating status and enhanced infiltrating lymphocytes in tumor-bearing rats. The expression of key immunoregulatory factors were upregulated in the vaccine group. The intensities of infiltrating CD4+ and CD8+ T cells and NK cells were significantly increased in the vaccine group compared to the control group (P<0.05). This protection was mainly dependent on the IFN-γ pathway and, to a much lesser extent, by the IL-4 pathway. The tumor cells only irradiated by X-ray as the control group still showed a slight immune effect, indicating that irradiated cells may also cause certain immune antigen exposure, but the efficacy was not as significant as that of the TSA-modified tumor vaccine. Our study revealed the potential application of the TSA-modified tumor vaccine as a novel tumor vaccine against tumor refractoriness and growth. These findings offer a better understanding of the immunomodulatory effects of the vaccine against latent tumorigenesis and progression. This tumor vaccine therapy may increase antigen exposure, synergistically activate the immune system, and ultimately improve remission rates. A vaccine strategy designed to induce effective tumor immune response is being considered for cancer immunotherapy.

Gastric cancer with brain metastasis: from molecular characteristics and treatment

Gastric cancer is one of the cancers with increasing incidence and ranks fourth globally among the most frequent causes of cancer-related mortality. Early gastric cancer is often asymptomatic or presents with atypical symptoms, and the majority of patients present with advanced disease upon diagnosis. Brain metastases are present in approximately 1% of gastric cancer patients at the time of diagnosis, which significantly contributed to the overall mortality of the disease worldwide. Conventional therapies for patients with brain metastases remain limited and the median overall survival of patients is only 8 months in advanced cases. Recent studies have improved our understanding of the molecular mechanisms underlying gastric cancer brain metastases, and immunotherapy has become an important treatment option in combination with radiotherapy, chemotherapy, targeted therapy and surgery. This review aims to provide insight into the cellular processes involved in gastric cancer brain metastases, discuss diagnostic approaches, evaluate the integration of immune checkpoint inhibitors into treatment and prognosis, and explore the predictive value of biomarkers in immunotherapy.

Advances in bio-immunotherapy for castration-resistant prostate cancer

Prostate cancer is one of the significant diseases that threaten the survival of men worldwide, with the progression of androgen deprivation therapy, become much rely on it, finally, developed into castration-resistant prostate cancer (ADT). In western countries, ranks second in incidence, and in China, with increasing lifespan, the incidence of prostate cancer is rising steadily. Although chemotherapy agents, such as taxane, have achieved some efficacy, treatment failure still occur. As sensitivity of hormone levels change, the disease can progress to castrate-resistant prostate cancer. Because of the poor efficacy of traditional surgery, endocrine therapy, radiation therapy, and chemotherapy, the treatment options for castrate-resistant prostate cancer are limited. Advanced prostate cancer can progress on immunotherapy, and thus, bio -immunotherapy targeting the unique, prostate microenvironment is an important option. In this paper, we systematically revealed the role of three types of bio-immunotherapies (immune checkpoint inhibitors, tumors, vaccines, cytokines) in castrate-resistant prostate cancer, providing a reference for clinical treatment of prostate cancer.

Analysis of thymic generation of shared T-cell receptor α repertoire associated with recognition of tumor antigens shows no preference for neoantigens over wild-type antigens

BACKGROUND

The number of mutations in cancer cells is an important predictor of a positive response to cancer immunotherapy. It has been suggested that the neoantigens produced by these mutations are more immunogenic than nonmutated tumor antigens, which are likely to be protected by immunological tolerance. However, the mechanisms of tolerance as regards tumor antigens are incompletely understood.

METHODS

Here, we have analyzed the impact of thymic negative selection on shared T-cell receptor (TCR) repertoire associated with the recognition of either mutated or nonmutated tumor antigens by comparing previously known TCR-antigen-pairs to TCR repertoires of 21 immunologically healthy individuals.

RESULTS

Our results show that TCRα chains associated with either type of tumor antigens are readily generated in the thymus, at a frequency similar to TCRα chains associated with nonself. In the peripheral repertoire, the relative clone size of nonself-associated chains is higher than that of the tumor antigens, but importantly, there is no difference between TCRα chains associated with mutated or nonmutated tumor antigens.

CONCLUSION

This suggests that the tolerance mechanisms protecting nonmutated tumor antigens are non-deletional and therefore potentially reversible. As unmutated antigens are, unlike mutations, shared by a large number of patients, they may offer advantages in designing immunological approaches to cancer treatment.

Fibronectin-Coated Metal-Phenolic Networks for Cooperative Tumor Chemo-/Chemodynamic/Immune Therapy via Enhanced Ferroptosis-Mediated Immunogenic Cell Death

The development of nanomedicine formulations to overcome the disadvantages of traditional chemotherapeutic drugs and integrate cooperative theranostic modes still remains challenging. Herein, we report the facile construction of a multifunctional theranostic nanoplatform based on doxorubicin (DOX)-loaded tannic acid (TA)-iron (Fe) networks (for short, TAF) coated with fibronectin (FN) for combination tumor chemo-/chemodynamic/immune therapy under the guidance of magnetic resonance (MR) imaging. We show that the DOX-TAF@FN nanocomplexes created through in situ coordination of TA and Fe(III) and physical coating with FN have a mean particle size of 45.0 nm, are stable, and can release both DOX and Fe in a pH-dependent manner. Due to the coexistence of the TAF network and DOX, significant immunogenic cell death can be caused through enhanced ferroptosis of cancer cells via cooperative Fe-based chemodynamic therapy and DOX chemotherapy. Through further treatment with programmed cell death ligand 1 antibody for an immune checkpoint blockade, the tumor treatment efficacy and the associated immune response can be further enhanced. Meanwhile, with FN-mediated targeting, the DOX-TAF@FN platform can specifically target tumor cells with high expression of α_vβ₃ integrin. Finally, the TAF network also enables the DOX-TAF@FN to have an r₁ relaxivity of 6.1 mM^-1 s^-1 for T₁-weighted MR imaging of tumors. The developed DOX-TAF@FN nanocomplexes may represent an updated multifunctional nanosystem with simple compositions for cooperative MR imaging-guided targeted chemo-/chemodynamic/immune therapy of tumors.

Identification and Validation of the lncRNA BACE1-AS as Immune-Related Influencing Factor in Tumorigenesis following Pan-Carcinoma Analysis

BACKGROUND

The lncRNA BACE1-AS was identified as a plasma molecular marker in the early diagnosis of Alzheimer's disease, but its role in tumors remains poorly defined.

METHODS

The expression patterns, genomic mutation, and prognostic significance of BACE1-AS in pan-cancers were compared by analyzing 32 types of tumors from The Cancer Genome Atlas and cBioPortal databases. The relationships between BACE1-AS expression levels and the degree of immune cell infiltration, immune components, and immune-related genes were explored. The possible molecular mechanisms of BACE1-AS in tumors were explored using gene set enrichment analysis (GSEA). Finally, the role of BACE1-AS in hepatocellular carcinoma was confirmed via quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

BACE1-AS expression levels were significantly upregulated in LIHC, GBM, KIRC, CHOL, STAD, KICH, COAD, and PRAD. Higher expression levels of BACE1-AS were associated with worse overall survival in patients with HNSC and LIHC, while the opposite was found in PCPG and THCA. The overall mutation rate of BACE1-AS in pan-cancer was only approximately 0.9%, and it occurred mainly in uveal melanoma and uterine carcinoma. Generally, BACE1-AS expression was negatively correlated with the immune microenvironment. BACE1-AS expression was mainly related to naïve B cells, activated memory CD4 T cells, monocytes, M1 macrophages, M2 macrophages, and resting mast cells. The potential mechanisms of BACE1-AS in tumors were mainly via regulating the activities of B cell-mediated immunity, immune response regulating cell surface receptor signaling, RNA binding in posttranscriptional gene silencing, B cell receptor signaling pathways, and immune receptor activity. Finally, the qRT-PCR results confirmed that the expression levels of BACE1-AS in hepatocellular carcinoma cell lines were upregulated.

CONCLUSIONS

Overall, our results suggest that BACE1-AS is associated with the expression, prognosis, and rate of immune cell infiltration of most tumors. Thus, BACE1-AS may be a potential target for immunotherapies aimed at improving cancer patient outcomes.

Mechanisms of Immunosuppressive Tumor Evasion: Focus on Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a malignancy with high heterogeneity in its biological features and treatments. Although the overall survival (OS) of patients with ALL has recently improved considerably, owing to the application of conventional chemo-therapeutic agents, approximately 20% of the pediatric cases and 40-50% of the adult patients relapse during and after the treatment period. The potential mechanisms that cause relapse involve clonal evolution, innate and acquired chemoresistance, and the ability of ALL cells to escape the immune-suppressive tumor response. Currently, immunotherapy in combination with conventional treatment is used to enhance the immune response against tumor cells, thereby significantly improving the OS in patients with ALL. Therefore, understanding the mechanisms of immune evasion by leukemia cells could be useful for developing novel therapeutic strategies.

The Importance of Metabolism for Immune Homeostasis in Allergic Diseases

There is increasing evidence that the metabolic status of T cells and macrophages is associated with severe phenotypes of chronic inflammation, including allergic inflammation. Metabolic changes in immune cells have a crucial role in their inflammatory or regulatory responses. This notion is reinforced by metabolic diseases influencing global energy metabolism, such as diabetes or obesity, which are known risk factors of severity in inflammatory conditions, due to the metabolic-associated inflammation present in these patients. Since several metabolic pathways are closely tied to T cell and macrophage differentiation, a better understanding of metabolic alterations in immune disorders could help to restore and modulate immune cell functions. This link between energy metabolism and inflammation can be studied employing animal, human or cellular models. Analytical approaches rank from classic immunological studies to integrated analysis of metabolomics, transcriptomics, and proteomics. This review summarizes the main metabolic pathways of the cells involved in the allergic reaction with a focus on T cells and macrophages and describes different models and platforms of analysis used to study the immune system and its relationship with metabolism.