Mitochondrial C1QBP is essential for T cell antitumor function by maintaining mitochondrial plasticity and metabolic fitness.

The metabolic stress present in the tumor microenvironment of many cancers can attenuate T cell antitumor activity, which is intrinsically controlled by the mitochondrial plasticity, dynamics, metabolism, and biogenesis within these T cells. Previous studies have reported that the complement C1q binding protein (C1QBP), a mitochondrial protein, is responsible for maintenance of mitochondrial fitness in tumor cells; however, its role in T cell mitochondrial function, particularly in the context of an antitumor response, remains unclear. Here, we show that C1QBP is indispensable for T cell antitumor immunity by maintaining mitochondrial integrity and homeostasis. This effect holds even when only one allele of C1qbp is functional. Further analysis of C1QBP in the context of chimeric antigen receptor (CAR) T cell therapy against the murine B16 melanoma model confirmed the cell-intrinsic role of C1QBP in regulating the antitumor functions of CAR T cells. Mechanistically, we found that C1qbp knocking down impacted mitochondrial biogenesis via the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor gamma coactivator 1-alpha signaling pathway, as well as mitochondrial morphology via the phosphorylation of mitochondrial dynamics protein dynamin-related protein 1. In summary, our study provides a novel mitochondrial target to potentiate the plasticity and metabolic fitness of mitochondria within T cells, thus improving the immunotherapeutic potential of these T cells against tumors.

Complement C1q binding protein regulates T cells' mitochondrial fitness to affect their survival, proliferation, and anti-tumor immune function.

T cells survival, proliferation, and anti-tumor response are closely linked to their mitochondrial health. Complement C1q binding protein (C1QBP) promotes mitochondrial fitness through regulation of mitochondrial metabolism and morphology. However, whether C1QBP regulates T cell survival, proliferation, and anti-tumor immune function remains unclear. Our data demonstrated that C1QBP knockdown induced the accumulation of reactive oxygen species (ROS) and the loss of mitochondrial membrane potential to impair T cell mitochondrial fitness. At the same time, C1QBP insufficiency reduced the recruitment of the anti-apoptotic proteins, including Bcl-2 and Bcl-XL, and repressed caspase-3 activation and poly (ADP-ribose) polymerase cleavage, which consequently accelerated the T cell apoptotic process. In contrast, C1QBP knockdown rendered T cells with relatively weaker proliferation due to the inhibition of AKT/mTOR signaling pathway. To investigate the exact role of C1QBP in anti-tumor response, C1QBP+/- and C1QBP+/+ mice were given a subcutaneous injection of murine MC38 cells. We found that C1QBP deficiency attenuated T cell tumor infiltration and aggravated tumor-infiltrating T lymphocytes (TIL) exhaustion. Moreover, we further clarified the potential function of C1QBP in chimeric antigen receptor (CAR) T cell immunotherapy. Our data showed that C1QBP+/- CAR T cells exhibited relatively weaker anti-tumor response than the corresponding C1QBP+/+ CAR T cells. Given that C1QBP knockdown impairs T cells' anti-apoptotic capacity, proliferation as well as anti-tumor immune function, development of the strategy for potentiation of T cells' mitochondrial fitness through C1QBP could potentially optimize the efficacy of the related immunotherapy.

Adenovirus vaccine therapy with CD137L promotes CD8+ DCs-mediated multifunctional CD8+ T cell immunity and elicits potent anti-tumor activity.

Renal carcinoma progresses aggressively in patients with metastatic disease while curative strategies are limited. Here, we constructed a recombinant non-replicating adenovirus (Ad) vaccine encoding an immune activator, CD137L, and a tumor antigen, CAIX, for treating renal carcinoma. In a subcutaneous tumor model, tumor growth was significantly suppressed in the Ad-CD137L/CAIX vaccine group compared with the single vaccine group. The induction and maturity of CD11C+ and CD8+CD11C+ dendritic cell (DC) subsets were promoted in Ad-CD137L/CAIX co-immunized mice. Furthermore, the Ad-CD137L/CAIX vaccine elicited stronger tumor-specific multifunctional CD8+ T cell immune responses as demonstrated by increased proliferation and cytolytic function of CD8+ T cells. Notably, depletion of CD8+ T cells greatly compromised the effective protection provided by Ad-CD137L/CAIX vaccine, suggesting an irreplaceable role of CD8+ T cells for the immunopotency of the vaccine. In both lung metastatic and orthotopic models, Ad-CD137L/CAIX vaccine treatment significantly decreased tumor metastasis and progression and increased the induction of tumor-specific multifunctional CD8+ T cells, in contrast to treatment with the Ad-CAIX vaccine alone. The Ad-CD137L/CAIX vaccine also augmented the tumor-specific multifunctional CD8+ T cell immune response in both orthotopic and metastatic models. These results indicated that Ad-CD137L/CAIX vaccine elicited a potent anti-tumor activity by inducing CD8+DC-mediated multifunctional CD8+ T cell immune responses. The potential strategy of CD137L-based vaccine might be served as a novel treatment for renal carcinoma or other malignant tumors.

Co-immunization with L-Myc enhances CD8+ or CD103+ DCs mediated tumor-specific multi-functional CD8+ T cell responses.

Renal carcinoma shows a high risk of invasion and metastasis without effective treatment. Herein, we developed a chitosan (CS) nanoparticle-mediated DNA vaccine containing an activated factor L-Myc and a tumor-specific antigen CAIX for renal carcinoma treatment. The subcutaneous tumor models were intramuscularly immunized with CS-pL-Myc/pCAIX or control vaccine, respectively. Compared with single immunization group, the tumor growth was significantly suppressed in CS-pL-Myc/pCAIX co-immunization group. The increased proportion and mature of CD11c+ DCs, CD8+ CD11c+ DCs and CD103+ CD11c+ DCs were observed in the splenocytes from CS-pL-Myc/pCAIX co-immunized mice. Furthermore, the enhanced antigen-specific CD8+ T lymphocyte proliferation, cytotoxic T lymphocyte (CTL) responses, and multi-functional CD8+ T cell induction were detected in CS-pL-Myc/pCAIX co-immunization group compared with CS-pCAIX immunization group. Of note, the depletion of CD8 T cells resulted in the reduction of CD8+ T cells or CD8+ CD11c+ DCs and the loss of anti-tumor efficacy induced by CS-pL-Myc/pCAIX vaccine, suggesting the therapeutic efficacy of the vaccine was required for CD8+ DCs and CD103+ DCs mediated CD8+ T cells responses. Likewise, CS-pL-Myc/pCAIX co-immunization also significantly inhibited the lung metastasis of renal carcinoma models accompanied with the increased induction of multi-functional CD8+ T cell responses. Therefore, these results indicated that CS-pL-Myc/pCAIX vaccine could effectively induce CD8+ DCs and CD103+ DCs mediated tumor-specific multi-functional CD8+ T cell responses and exert the anti-tumor efficacy. This vaccine strategy offers a potential and promising approach for solid or metastatic tumor treatment.

gB co-immunization with GP96 enhances pulmonary-resident CD8 T cells and exerts a long-term defence against MCMV pneumonitis.

Human cytomegalovirus (HCMV) infection in the respiratory tract leads to pneumonitis in immunocompromised hosts without available vaccine. Considering cytomegalovirus (CMV) mainly invades through the respiratory tract, CMV-specific pulmonary mucosal vaccine development that provides a long-lasting protection against CMV challenge gains our attention. In this study, N-terminal domain of GP96 (GP96-NT) was used as a mucosal adjuvant to enhance the induction of pulmonary-resident CD8 T cells elicited by MCMV glycoprotein B (gB) vaccine. Mice were intranasally co-immunized with 50 µg pgB and equal amount of pGP96-NT vaccine 4 times at 2-week intervals, and then i.n. challenged with MCMV at 16 weeks after the last immunization. Compared with pgB immunization alone, co-immunization with pgB/pGP96-NT enhanced a long-lasting protection against MCMV pneumonitis by significantly improved pneumonitis pathology, enhanced bodyweight, reduced viral burdens and increased survival rate. Moreover, the increased CD8 T cells were observed in lung but not spleen from pgB/pGP96-NT co-immunized mice. The increments of pulmonary CD8 T cells might be mainly due to non-circulating pulmonary-resident CD8 T-cell subset expansion but not circulating CD8 T-cell populations that home to inflammation site upon MCMV challenge. Finally, the deterioration of MCMV pneumonitis by depletion of pulmonary site-specific CD8 T cells in mice that were pgB/pGP96-NT co-immunization might be a clue to interpret the non-circulating pulmonary-resident CD8 T subset expansion. These data might uncover a promising long-lasting prophylactic vaccine strategy against MCMV-induced pneumonitis.

Absent in melanoma 2 enhances anti-tumour effects of CAIX promotor controlled conditionally replicative adenovirus in renal cancer.

Conditionally replicative adenoviruses (CRAds) were promising approach for solid tumour treatment, but its oncolytic efficiency and toxicity are still not satisfactory for further clinical application. Here, we developed the CAIX promotor (CAIXpromotor )-controlled CRAd armed with a tumour suppressor absent in melanoma 2 (AIM2) to enhance its oncolytic potency. The CAIXpromotor -AIM2 adenoviruses (Ad-CAIXpromotor -AIM2) could efficiently express E1A and AIM2 in renal cancer cells. Compared with Ad-CAIXpromotor , Ad-CAIXpromotor -AIM2 significantly inhibited cell proliferation and enhanced cell apoptosis and cell killing, thus resulting in the oncolytic efficiency in 786-O cells or OSRC-2 cells. To explore the therapeutic effect, various Ads were intratumourally injected into OSRC-2-xenograft mice. The tumour growth was remarkably inhibited in Ad-CAIXpromotor -AIM2-treated group as demonstrated by reduced tumour volume and weight with a low toxicity. The inflammasome inhibitor YVAD-CMK resulted in the reduction of anti-tumour activity by Ad-CAIXpromotor -AIM2 in vitro or in vivo, suggesting that inflammasome activation response was required for the enhanced therapeutic efficiency. Furthermore, lung metastasis of renal cancer mice was also suppressed by Ad-CAIXpromotor -AIM2 treatment accompanied by the decreased tumour fossil in lung tissues. These results indicated that the tumour-specific Ad-CAIXpromotor -AIM2 could be applied for human renal cancer therapy. The therapeutic strategy of AIM2-based CRAds could be a potential and promising approach for the therapy of primary solid or metastasis tumours.

ISG12a and its interaction partner NR4A1 are involved in TRAIL-induced apoptosis in hepatoma cells.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in cancer cells while sparing normal cells, thereby leading to the development of TRAIL receptor agonists for cancer treatment. However, these agonist-based therapeutics exhibit little clinical benefits due to the lack of biomarkers to predict whether patients are responsive to the treatment, as well as determine the resistance of cancer cells to TRAIL-based agonists. Our previous study has demonstrated that ISG12a enhances TRAIL-induced apoptosis and might serve as a biomarker to predict the TRAIL response. The downstream mechanism by which ISG12a augments TRAIL-induced apoptosis remains to be elucidated. In this study, we found that ISG12a was localized in the mitochondria and nucleus and augmented TRAIL-induced apoptosis through intrinsic apoptotic pathway. In addition, ISG12a interacted with NR4A1 and promoted its nuclear-to-cytoplasm translocation. Upon translocate to cytoplasm, NR4A1 targeted mitochondria and induced Bcl2 conformational change, thereby exposing its BH3 domain. Moreover, TRAIL treatment can induce NR4A1 expression through the activation of NF-κB in TRAIL-resistant Huh7 hepatoma cells. Knockdown of NR4A1 could overcome TRAIL resistance. However, in TRAIL-sensitive LH86 liver cancer cells, TRAIL activated the Jun N-terminal kinases signalling pathway. Overall, these results showed that both ISG12a and its interaction partner NR4A1 are involved in TRAIL-mediated apoptosis in hepatoma cells.

AIM2 is a potential therapeutic target in human renal carcinoma and suppresses its invasion and metastasis via enhancing autophagy induction.

Absent in melanoma 2 (AIM2) as a tumor suppressor is recently recognized to play an important role in many human solid tumors. However, the biological significance and function of AIM2 in renal cell carcinoma (RCC) remain unknown. In this study, we proposed to investigate the clinicopathological and prognostic significance of AIM2 in RCC patient specimens, to analyze the correlation between AIM2 expression and disease progression, and to further investigate the role and mechanism of AIM2 in malignant behaviors of renal carcinoma by cellular and animal models. The correlation analysis showed that low AIM2 expression was significantly correlated with lymph node metastasis, poor 5-year overall (P < 0.05) and disease-specific survival (P < 0.05) in RCC patients. Over-expression of AIM2 in 786-O or OSRC-2 cells suppressed the cell proliferation, migration and invasion as compared with control. The increased AIM2 expression enhanced the expression of autophagy-related genes (Bcl-2, Beclin-1, LC3-Ⅱ, and ATG-5) and increased the ratio of LC3-Ⅱ/LC3-Ⅰin renal carcinoma cells. Of note, the blockade of autophagy by 3-Methyladenine (3-MA) abrogated the inhibition of cell migration and invasion by over-expressing AIM2, indicated that AIM2 suppressed the malignant behaviors of renal carcinoma by enhancing the induction of autophagy. Furthermore, 3-MA abolished the prevention of tumor growth on nude mouse established by AIM2-OSRC-2 cells. Our results suggested that AIM2 might serve as a novel prognostic indicator as well as a potential therapeutic target for renal carcinoma treatment.

H1/pAIM2 nanoparticles exert anti-tumour effects that is associated with the inflammasome activation in renal carcinoma.

Renal cell carcinoma (RCC) is a high metastasis tumour with less effective treatment available currently. Absent in melanoma 2 (AIM2) as a tumour suppressor might be used as a potential therapeutic target for RCC treatment. Here, we found that AIM2 expression was significantly decreased in RCC patient specimens and renal carcinoma cell lines (786-O and OSRC-2). To establish a safe and effective AIM2 gene delivery system, we formed the nanoparticles consisting of a folate grafted PEI600-CyD (H1) nanoparticle-mediated AIM2 gene (H1/pAIM2) as an effective delivery agent. Delivery of H1/pAIM2 in renal carcinoma cells could remarkably increase the expression of AIM2, and subsequently decrease cell proliferation, migration, and invasion as well as enhance cell apoptosis. In order to evaluate the therapeutic efficacy of AIM2 in vivo, H1/pAIM2 nanoparticles were injected intratumorally into 786-O-xenograft mice. Administration of H1/pAIM2 nanoparticles could inhibit the tumour growth as evidenced by reduced tumour volume and weight. Furthermore, Blockade of inflammasome activation triggered by H1/pAIM2 nanoparticles using inflammasome inhibitor YVAD-CMK abrogated the anti-tumoral activities of H1/AIM2. These results indicated the therapeutic effect of H1/pAIM2 nanoparticles was mainly attributable to its capability to enhance the inflammasome activation. H1/AIM2 nanoparticles might act as an efficient therapeutic approach for RCC treatment.

DNA-delivered monoclonal antibodies targeting the p53 R175H mutant epitope inhibit tumor development in mice.

The tumor suppressor p53 is the most common mutated gene in cancer, with the R175H as the most frequent p53 missense mutant. However, there are currently no approved targeted therapies or immunotherapies against mutant p53. Here, we characterized and investigated a monoclonal antibody (mAb) that recognizes the mutant p53-R175H for its affinity, specificity, and activity against tumor cells in vitro. We then delivered DNA plasmids expressing the anti-R175H mAb or a bispecific antibody (BsAb) into mice to evaluate their therapeutic effects. Our results showed that the anti-R175H mAb specifically bound to the p53-R175H antigen with a high affinity and recognized the human mutant p53-R175H antigen expressed on HEK293T or MC38 cells, with no cross-reactivity with wild-type p53. In cultured cells, the anti-R175H mAb showed higher cytotoxicity than the control but did not induce antibody-dependent cellular cytotoxicity. We made a recombinant MC38 mouse cell line (MC38-p53-R175H) that overexpressed the human p53-R175H after knocking out the endogenous mutant p53 alleles. In vivo, administration of the anti-R175H mAb plasmid elicited a robust anti-tumor effect against MC38-p53-R175H in mice. The administration of the anti-R175H BsAb plasmid showed no therapeutic effects, yet potent anti-tumor activity was observed in combination with the anti-PD-1 antibody. These results indicate that targeting specific mutant epitopes using DNA-delivered mAbs or BsAbs presents a form of improved natural immunity derived from tumor-infiltrating B cells and plasma cells against intracellular tumor antigens.

Cancer-educated neutrophils promote lung cancer progression via PARP-1-ALOX5-mediated MMP-9 expression.

OBJECTIVE: Neutrophils are one of the most predominant infiltrating leukocytes in lung cancer tissues and are associated with lung cancer progression. How neutrophils promote lung cancer progression, however, has not been established. METHODS: Kaplan-Meier plotter online analysis and tissue immunohistochemistry were used to determine the relationship between neutrophils and overall survival in lung cancer patients. The effect of neutrophils on lung cancer was determined using the Transwell migration assay, a proliferation assay, and a murine tumor model. Gene knockdown was used to determine poly ADP-ribose polymerase (PARP)-1 function in lung cancer-educated neutrophils. Western blot analysis and gelatin zymography were used to demonstrate the correlation between PARP-1 and matrix metallopeptidase 9 (MMP-9). Immunoprecipitation coupled to mass spectrometry (IP/MS) was used to identify the proteins interacting with PARP-1. Co-immunoprecipitation (Co-IP) was used to confirm that PARP-1 interacts with arachidonate 5-lipooxygenase (ALOX5). Neutrophil PARP-1 blockage by AG14361 rescued neutrophil-promoted lung cancer progression. RESULTS: An increased number of infiltrating neutrophils was negatively associated with overall survival in lung cancer patients (P < 0.001). Neutrophil activation promoted lung cancer cell invasion, migration, and proliferation in vitro, and murine lung cancer growth in vivo. Mechanistically, PARP-1 was shown to be involved in lung cancer cell-induced neutrophil activation to increase MMP-9 expression through interacting and stabilizing ALOX5 by post-translational protein modification (PARylation). Blocking PARP-1 by gene knockdown or AG14361 significantly decreased ALOX5 expression and MMP-9 production, and eliminated neutrophil-mediated lung cancer cell invasion and in vivo tumor growth. CONCLUSIONS: We identified a novel mechanism by which PARP-1 mediates lung cancer cell-induced neutrophil activation and PARylates ALOX5 to regulate MMP-9 expression, which exacerbates lung cancer progression.

The next-generation DNA vaccine platforms and delivery systems: advances, challenges and prospects.

Vaccines have proven effective in the treatment and prevention of numerous diseases. However, traditional attenuated and inactivated vaccines suffer from certain drawbacks such as complex preparation, limited efficacy, potential risks and others. These limitations restrict their widespread use, especially in the face of an increasingly diverse range of diseases. With the ongoing advancements in genetic engineering vaccines, DNA vaccines have emerged as a highly promising approach in the treatment of both genetic diseases and acquired diseases. While several DNA vaccines have demonstrated substantial success in animal models of diseases, certain challenges need to be addressed before application in human subjects. The primary obstacle lies in the absence of an optimal delivery system, which significantly hampers the immunogenicity of DNA vaccines. We conduct a comprehensive analysis of the current status and limitations of DNA vaccines by focusing on both viral and non-viral DNA delivery systems, as they play crucial roles in the exploration of novel DNA vaccines. We provide an evaluation of their strengths and weaknesses based on our critical assessment. Additionally, the review summarizes the most recent advancements and breakthroughs in pre-clinical and clinical studies, highlighting the need for further clinical trials in this rapidly evolving field.

Remodeling of anti-tumor immunity with antibodies targeting a p53 mutant.

BACKGROUND: p53, the most frequently mutated gene in cancer, lacks effective targeted drugs. METHODS: We developed monoclonal antibodies (mAbs) that target a p53 hotspot mutation E285K without cross-reactivity with wild-type p53. They were delivered using lipid nanoparticles (LNPs) that encapsulate DNA plasmids. Western blot, BLI, flow cytometry, single-cell sequencing (scRNA-seq), and other methods were employed to assess the function of mAbs in vitro and in vivo. RESULTS: These LNP-pE285K-mAbs in the IgG1 format exhibited a robust anti-tumor effect, facilitating the infiltration of immune cells, including CD8+ T, B, and NK cells. scRNA-seq revealed that IgG1 reduces immune inhibitory signaling, increases MHC signaling from B cells to CD8+ T cells, and enriches anti-tumor T cell and B cell receptor profiles. The E285K-mAbs were also produced in the dimeric IgA (dIgA) format, whose anti-tumor activity depended on the polymeric immunoglobulin receptor (PIGR), a membrane Ig receptor, whereas that of IgG1 relied on TRIM21, an intracellular IgG receptor. CONCLUSIONS: Targeting specific mutant epitopes using DNA-encoded and LNP-delivered mAbs represents a potential precision medicine strategy against p53 mutants in TRIM21- or PIGR-positive cancers.

Artificial intelligence-powered discovery of small molecules inhibiting CTLA-4 in cancer.

BACKGROUND/OBJECTIVES: Checkpoint inhibitors, which generate durable responses in many cancer patients, have revolutionized cancer immunotherapy. However, their therapeutic efficacy is limited, and immune-related adverse events are severe, especially for monoclonal antibody treatment directed against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which plays a pivotal role in preventing autoimmunity and fostering anticancer immunity by interacting with the B7 proteins CD80 and CD86. Small molecules impairing the CTLA-4/CD80 interaction have been developed; however, they directly target CD80, not CTLA-4. SUBJECTS/METHODS: In this study, we performed artificial intelligence (AI)-powered virtual screening of approximately ten million compounds to identify those targeting CTLA-4. We validated the hits molecules with biochemical, biophysical, immunological, and experimental animal assays. RESULTS: The primary hits obtained from the virtual screening were successfully validated in vitro and in vivo. We then optimized lead compounds and obtained inhibitors (inhibitory concentration, 1 micromole) that disrupted the CTLA-4/CD80 interaction without degrading CTLA-4. CONCLUSIONS: Several compounds inhibited tumor development prophylactically and therapeutically in syngeneic and CTLA-4-humanized mice. Our findings support using AI-based frameworks to design small molecules targeting immune checkpoints for cancer therapy.

Comparison of DNA vaccines with AS03 as an adjuvant and an mRNA vaccine against SARS-CoV-2.

Emerging variants of SARS-CoV-2 call for frequent changes in vaccine antigens. Nucleic acid-based vaccination strategies are superior as the coding sequences can be easily altered with little impact on downstream production. mRNA vaccines, including variant-specific boosters, are approved for SARS-CoV-2. Here, we tested the efficacy of DNA vaccines against the SARS-CoV-2 Spike aided by the AS03 adjuvant using electroporation and compared their immunogenicity with an approved mRNA vaccine (mRNA-1273). DNA vaccination elicited robust humoral and cellular immune responses in C57BL/6 mice with Spike-specific antibody neutralization and T cells produced from 20 µg DNA vaccines similar to that from 0.5 µg mRNA-1273. Furthermore, a Nanoplasmid-based vector further increased the immunogenicity. Our results indicate that adjuvants are critical to the efficacy of DNA vaccines in stimulating robust immune responses against Spike, highlighting the feasibility of plasmid DNA as a rapid nucleic acid-based vaccine approach against SARS-CoV-2 and other emerging infectious diseases.

AI-powered discovery of a novel p53-Y220C reactivator.

Introduction: The p53-Y220C mutation is one of the most common mutations that play a major role in cancer progression. Methods: In this study, we applied artificial intelligence (AI)-powered virtual screening to identify small-molecule compounds that specifically restore the wild-type p53 conformation from p53-Y220C. From 10 million compounds, the AI algorithm selected a chemically diverse set of 83 high-scoring hits, which were subjected to several experimental assays using cell lines with different p53 mutations. Results: We identified one compound, H3, that preferentially killed cells with the p53-Y220C mutation compared to cells with other p53 mutations. H3 increased the amount of folded mutant protein with wild-type p53 conformation, restored its transcriptional functions, and caused cell cycle arrest and apoptosis. Furthermore, H3 reduced tumorigenesis in a mouse xenograft model with p53-Y220C-positive cells. Conclusion: AI enabled the discovery of the H3 compound that selectively reactivates the p53-Y220C mutant and inhibits tumor development in mice.

HMGB1/GPC3 dual targeting vaccine induces dendritic cells-mediated CD8+T cell immune response and elicits potential therapeutic effect in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a fatal malignant tumor, but effective clinical interventions are limited. PLGA/PEI-mediated DNA vaccine encoding the dual targets of high-mobility group box 1 (HMGB1) or GPC3 was developed for HCC treatment. Compared with PLGA/PEI-GPC3 immunization, PLGA/PEI-HMGB1/GPC3 co-immunization significantly inhibited the subcutaneous tumor growth, while increasing the infiltration of CD8+T cells and DCs. Furthermore, the PLGA/PEI-HMGB1/GPC3 vaccine induced a strong CTL effect and promoted functional CD8+T cell proliferation. Intriguingly, the depletion assay proved that the therapeutic effect PLGA/PEI-HMGB1/GPC3 vaccine was dependent on antigen-specific CD8+T cell immune responses. In the rechallenge experiment, PLGA/PEI-HMGB1/GPC3 vaccine provided a long-lasting resistance to the growth of the contralateral tumor by inducing the memory CD8+T cell responses. Collectively, PLGA/PEI-HMGB1/GPC3 vaccine could induce a strong and long-lasting CTL effect and inhibit the tumor progression or re-attack. Therefore, the combined co-immunization of PLGA/PEI-HMGB1/GPC3 might be served as an effective anti-tumor strategy against HCC.

Adenovirus-assembled DC vaccine induces dual-targeting CTLs for tumor antigen and adenovirus to eradicate tumors.

The dendritic cell (DC) vaccine is a promising cancerimmunotherapy strategy, but its efficacy in treating the solid tumor is limited. To overcome this limitation, an oncolytic adenovirus (OAV-IL-12) was developed to enhance antigen targeting ability of adenovirus-assembled DC vaccine (DCs-CD137L/CAIX) for renal carcinoma treatment. Peritumoral administration of OAV-IL-12 increased the number of tumor-infiltrating DCs and their subsets (CD8+DCs and CD103+DCs). Combining OAV-IL-12 with DCs-CD137L/CAIX significantly inhibited the growth of subcutaneous tumors by inducing potent cytotoxic T lymphocyte (CTL) effect and improving the immune infiltration in tumor lesions. Interestingly, this treatment also reduced tumor growth distal to the OAV-IL-12 injecting side via eliciting a systemic CTL response. Furthermore, OAV-IL-12 potentiated DCs-CD137L/CAIX treatment induced dual CTL responses against both CAIX and adenovirus antigens. The therapeutic benefits of this treatment approach mainly relied on multifunctional CD8+T cell immune responses, as indicated by the depletion assay. Moreover, OAV-IL-12 potentiated DCs-CD137L/CAIX treatment generated a long-lasting protective effect against tumors by inducing memory CD8+T cell immune responses. These results suggest that the effective tumor targeting of the adenovirus-based DC vaccine, boosted by OAV-IL-12, is a promising treatment approach for renal carcinoma and other solid tumors.

The co-delivery of adenovirus-based immune checkpoint vaccine elicits a potent anti-tumor effect in renal carcinoma.

Immune-based checkpoint therapy has made significant progress in cancer treatment, but its therapeutic effect is limited. A replication-defective adenovirus (Ad) vaccine encoding tumor antigen carbonic anhydrase IX (CAIX) combined with Ad-encoding immune checkpoint PD-L1 was developed to treat renal carcinoma. Three tumor models, subcutaneous, lung metastasis and orthotopic tumor were established, and Ad vaccines were used to immunize them and evaluate the vaccine's therapeutic effect. Compared to the single Ad vaccine group, the subcutaneous tumor growth was significantly reduced in Ad-CAIX/Ad-PD-L1 combination group. Co-immunization of Ad-CAIX/Ad-PD-L1 enhanced the induction and maturation of CD11c+ or CD8+CD11c+ DCs in the spleen and tumor and promoted the strong tumor-specific CD8+ T cell immune responses. In vivo CD8 T cell deletion assay showed that the anti-tumor effect of the Ad-CAIX/Ad-PD-L1 vaccine was mainly dependent on functional CD8+ T cell immune responses. Furthermore, the Ad-CAIX/Ad-PD-L1 vaccine effectively inhibited tumor growth and lung metastasis in metastatic or orthotopic models. These results indicate that the combination strategy of the immune checkpoint vaccine shows promising potential as an approach for malignant tumor therapy.

Recombinant oncolytic adenovirus armed with CCL5, IL-12, and IFN-γ promotes CAR-T infiltration and proliferation in vivo to eradicate local and distal tumors.

The efficacy of chimeric antigen receptor T (CAR-T) cells for solid tumors remains unsatisfactory due to the limited tumor infiltration and immunosuppressive microenvironment. To overcome these limitations, the genetically engineered recombinant oncolytic adenoviruses (OAVs) that conditionally replicate in tumor cells were developed to modify the tumor microenvironment (TME) to facilitate CAR-T-mediated tumor eradication. Here in the present study, a novel recombinant OAV carrying CCL5, IL12, and IFN-γ controlled by Ki67 promoter was constructed (named AdKi67-C3). The antitumor activity of AdKi67-C3 was tested in vitro and in vivo by using mono administration or combing with CAR-T cells targeting B7H3. It proved that CCL5 expressed by AdKi67-C3 indeed induced more CAR-T migration in vitro and CAR-T infiltration in tumor mass in vivo. Meanwhile, cytokines of IFN-γ and IL12 secreted by AdKi67-C3-infected tumor cells significantly promoted proliferation and persistence of CAR-T cells in vitro and in vivo. In tumor-bearing xenograft mouse models of kidney, prostate or pancreatic cancer, local pretreatment with AdKi67-C3 dramatically enhanced CAR-T cell efficacy and eliminated local and distant tumors. More importantly, mice achieving complete tumor regression resisted to re-challenge with the same tumor cells, suggesting establishment of long-term antitumor immune response. Therefore, OAVs armored with cytokines could be developed as a bioenhancer to defeat the immunosuppressive microenvironment and improve therapeutic efficacy of CAR-T in solid tumors.