Despite enormous progress, advanced cancers are still one of the most serious medical problems in current society. Although various agents and therapeutic strategies with anticancer activity are known and used, they often fail to achieve satisfactory long-term patient outcomes and survival. Recently, immunotherapy has shown success in patients by harnessing important interactions between the immune system and cancer. However, many of these therapies lead to frequent side effects when administered systemically, prompting treatment modifications or discontinuation or, in severe cases, fatalities. New therapeutic approaches like intratumoral immunotherapy, characterized by reduced side effects, cost, and systemic toxicity, offer promising prospects for future applications in clinical oncology. In the context of locally advanced or metastatic cancer, combining diverse immunotherapeutic and other treatment strategies targeting multiple cancer hallmarks appears crucial. Such combination therapies hold promise for improving patient outcomes and survival and for promoting a sustained systemic response. This review aims to provide a current overview of immunotherapeutic approaches, specifically focusing on the intratumoral administration of drugs in patients with locally advanced and metastatic cancers. It also explores the integration of intratumoral administration with other modalities to maximize therapeutic response. Additionally, the review summarizes recent advances in intratumoral immunotherapy and discusses novel therapeutic approaches, outlining future directions in the field.

• Klíčová slova
• advanced and metastatic cancer, cancer, combination therapy, immunotherapy, intratumoral,
• MeSH
• imunoterapie * metody   MeSH
• injekce do léze MeSH
• kombinovaná terapie MeSH
• lidé MeSH
• metastázy nádorů MeSH
• nádory * terapie   imunologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: Autologous tumor cell-based vaccines (ATVs) aim to prevent and treat tumor metastasis by activating patient-specific tumor antigens to induce immune memory. However, their clinical efficacy is limited. Mannan-BAM (MB), a pathogen-associated molecular pattern (PAMP), can coordinate an innate immune response that recognizes and eliminates mannan-BAM-labeled tumor cells. TLR agonists and anti-CD40 antibodies (TA) can enhance the immune response by activating antigen-presenting cells (APCs) to present tumor antigens to the adaptive immune system. In this study, we investigated the efficacy and mechanism of action of rWTC-MBTA, an autologous whole tumor cell vaccine consisting of irradiated tumor cells (rWTC) pulsed with mannan-BAM, TLR agonists, and anti-CD40 antibody (MBTA), in preventing tumor metastasis in multiple animal models. METHODS: The efficacy of the rWTC-MBTA vaccine was evaluated in mice using breast (4T1) and melanoma (B16-F10) tumor models via subcutaneous and intravenous injection of tumor cells to induce metastasis. The vaccine's effect was also assessed in a postoperative breast tumor model (4T1) and tested in autologous and allogeneic syngeneic breast tumor models (4T1 and EMT6). Mechanistic investigations included immunohistochemistry, immunophenotyping analysis, ELISA, tumor-specific cytotoxicity testing, and T-cell depletion experiments. Biochemistry testing and histopathology of major tissues in vaccinated mice were also evaluated for potential systemic toxicity of the vaccine. RESULTS: The rWTC-MBTA vaccine effectively prevented metastasis and inhibited tumor growth in breast tumor and melanoma metastatic animal models. It also prevented tumor metastasis and prolonged survival in the postoperative breast tumor animal model. Cross-vaccination experiments revealed that the rWTC-MBTA vaccine prevented autologous tumor growth, but not allogeneic tumor growth. Mechanistic data demonstrated that the vaccine increased the percentage of antigen-presenting cells, induced effector and central memory cells, and enhanced CD4+ and CD8+ T-cell responses. T-cells obtained from mice that were vaccinated displayed tumor-specific cytotoxicity, as shown by enhanced tumor cell killing in co-culture experiments, accompanied by increased levels of Granzyme B, TNF-α, IFN-γ, and CD107a in T-cells. T-cell depletion experiments showed that the vaccine's antitumor efficacy depended on T-cells, especially CD4+ T-cells. Biochemistry testing and histopathology of major tissues in vaccinated mice revealed negligible systemic toxicity of the vaccine. CONCLUSION: The rWTC-MBTA vaccine demonstrated efficacy in multiple animal models through T-cell mediated cytotoxicity and has potential as a therapeutic option for preventing and treating tumor metastasis with minimal systemic toxicity.

• Klíčová slova
• Mannan-BAM, Metastasis, T-cell cytotoxicity, TLR agonists, rWTC-MBTA vaccine,
• MeSH
• antigeny CD40 MeSH
• antigeny nádorové MeSH
• imunologická paměť MeSH
• lidé MeSH
• mannany MeSH
• melanom * MeSH
• myši MeSH
• nádory prsu * terapie   MeSH
• protinádorové vakcíny * terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD40 MeSH
• antigeny nádorové MeSH
• mannany MeSH
• protinádorové vakcíny * MeSH

Cancer immunotherapy has shown remarkable clinical progress in recent years. Although age is one of the biggest leading risk factors for cancer development and older adults represent a majority of cancer patients, only a few new cancer immunotherapeutic interventions have been preclinically tested in aged animals. Thus, the lack of preclinical studies focused on age-dependent effect during cancer immunotherapy could lead to different therapeutic outcomes in young and aged animals and future modifications of human clinical trials. Here, we compare the efficacy of previously developed and tested intratumoral immunotherapy, based on the combination of polysaccharide mannan, toll-like receptor ligands, and anti-CD40 antibody (MBTA immunotherapy), in young (6 weeks) and aged (71 weeks) mice bearing experimental pheochromocytoma (PHEO). The presented results point out that despite faster growth of PHEO in aged mice MBTA intratumoral immunotherapy is effective approach without age dependence and could be one of the possible therapeutic interventions to enhance immune response to pheochromocytoma and perhaps other tumor types in aged and young hosts.

• Klíčová slova
• TLR ligands, age, anti-CD40 antibody, intratumoral immunotherapy, pancreatic adenocarcinoma, pheochromocytoma,
• MeSH
• antigeny CD40 MeSH
• feochromocytom * terapie   MeSH
• imunoterapie metody   MeSH
• lidé MeSH
• myši MeSH
• nádory nadledvin * terapie   MeSH
• senioři MeSH
• toll-like receptory MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• senioři MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• antigeny CD40 MeSH
• toll-like receptory MeSH

Despite constant advances in cancer research, the treatment of pancreatic adenocarcinoma remains extremely challenging. The intratumoral immunotherapy approach that was developed by our research group and was based on a combination of mannan-BAM, TLR ligands, and anti-CD40 antibody (MBTA) showed promising therapeutic effects in various murine tumor models, including a pancreatic adenocarcinoma model (Panc02). However, the efficacy of MBTA therapy in the Panc02 model was negatively correlated with tumor size at the time of therapy initiation. Here, we aimed to further improve the outcome of MBTA therapy in the Panc02 model using the glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON). The combination of intratumoral MBTA therapy and intraperitoneal administration of DON resulted in the complete elimination of advanced Panc02 subcutaneous tumors (140.8 ± 46.8 mm3) in 50% of treated animals and was followed by development of long-term immune memory. In the bilateral Panc02 subcutaneous tumor model, we observed a significant reduction in tumor growth in both tumors as well as prolonged survival of treated animals. The appropriate timing and method of administration of DON were also addressed to maximize its therapeutic effects and minimize its side effects. In summary, our findings demonstrate that the intraperitoneal application of DON significantly improves the efficacy of intratumoral MBTA therapy in both advanced and bilateral Panc02 subcutaneous tumor murine models.

• Klíčová slova
• Cancer, Glutamine antagonist, Immunotherapy, Intratumoral, Pancreatic adenocarcinoma,
• MeSH
• adenokarcinom * farmakoterapie   MeSH
• glutamin terapeutické užití   MeSH
• imunoterapie metody   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory slinivky břišní * farmakoterapie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glutamin MeSH

Immunotherapy has become an essential component in cancer treatment. However, the majority of solid metastatic cancers, such as pheochromocytoma, are resistant to this approach. Therefore, understanding immune cell composition in primary and distant metastatic tumors is important for therapeutic intervention and diagnostics. Combined mannan-BAM, TLR ligand, and anti-CD40 antibody-based intratumoral immunotherapy (MBTA therapy) previously resulted in the complete eradication of murine subcutaneous pheochromocytoma and demonstrated a systemic antitumor immune response in a metastatic model. Here, we further evaluated this systemic effect using a bilateral pheochromocytoma model, performing MBTA therapy through injection into the primary tumor and using distant (non-injected) tumors to monitor size changes and detailed immune cell infiltration. MBTA therapy suppressed the growth of not only injected but also distal tumors and prolonged MBTA-treated mice survival. Our flow cytometry analysis showed that MBTA therapy led to increased recruitment of innate and adaptive immune cells in both tumors and the spleen. Moreover, adoptive CD4+ T cell transfer from successfully MBTA-treated mice (i.e., subcutaneous pheochromocytoma) demonstrates the importance of these cells in long-term immunological memory. In summary, this study unravels further details on the systemic effect of MBTA therapy and its use for tumor and metastasis reduction or even elimination.

• Klíčová slova
• bilateral tumor model, immune memory, intratumoral immunotherapy, pheochromocytoma, toll-like receptor,
• Publikační typ
• časopisecké články MeSH