HPV16E7 tumor antigen modified by KDEL sequence induce specific cytotoxic T lymphocytes-dependent antitumor immunity

Pro-inflammatory responses after peptide-based cancer immunotherapy

Therapeutic vaccinations are designed to prevent cancer by inducing immune responses against tumor antigens. in cancer cells, tumor-associated antigens (TAA) or tumor-specific (mutated) derived peptides are presented within the clefts of main histocompatibility complex (MHC) class I or class II molecules, they either activate cytotoxic T-lymphocytes (CTLs), CD4+ T or CD8+ T lymphocytes, which release cytokines that can suppress tumor cells growth. In cancer immunotherapies, CD8+ T lymphocytes are a major mediator of tumor repression. The effect of peptide-based vaccinations on cytokines in the activating CD8+ T cell against targeted tumor antigens is the subject of this review. It is believed that peptide-based vaccines increased IFN-γ, TNF-α, IL-2, and IL-12, secreting CTL line by interacting with dendritic cell (DC), supposed to stimulate immune system. Additionally, mechanisms of CTL activation and dysfunction were also studied. According to most of the data resulted from in vivo and in vitro research works, it is assumed that peptide-based vaccines increased IFN-γ, TNF-α, IL-2, and IL-12.

Mechanism study of cross presentation of exogenous antigen induced by cholera toxin-like chimeric protein

Tumor subunit vaccines have great potential in personalized cancer immunotherapy. They are usually administered with adjuvant owing to their low immunogenicity. Cholera toxin (CT) is a biological adjuvant with diverse biological functions and a long history of use. Our earlier study revealed that a CT-like chimeric protein co-delivered with murine granulocyte-macrophage colony stimulating factor (mGM-CSF) and prostate cancer antigen epitope could co-stimulate dendritic cells (DCs) and enhance cross presentation of tumor epitope. To further study the molecular mechanism of CT-like chimeric protein in cross presentation, major histocompatibility complex class I (MHC I)-restricted epitope 257-264 of ovalbumin (OVAT) was used as a model antigen peptide in this study. Recombinant A subunit and pentameric B subunit of CT protein were respectively genetically constructed and purified. Then both assembled into AB5 chimeric protein in vitro. Three different chimeric biomacromolecules containing mGM-CSF and OVAT were constructed according to the different fusion sites and whether the endoplasmic reticulum (ER) retention sequence was included. It was found that A2 domain and B subunit of CT were both available for loading epitopes and retaining GM1 affinity. The binding activity of GM1 was positively correlated with antigen endocytosis. Once internalized, DCs became mature and cross-presented antigen. KDEL helped the whole molecule to be retained in the ER, and this improved the cross presentation of antigen on MHC I molecules. In conclusion, hexameric CT-like chimeric protein with dual effects of GM1 affinity and ER retention sequence were potential in improvement of cross presentation. The results laid a foundation for designing personalized tumor vaccine based on CT-like chimeric protein molecular structure.

KDEL Receptors: Pathophysiological Functions, Therapeutic Options, and Biotechnological Opportunities

KDEL receptors (KDELRs) are ubiquitous seven-transmembrane domain proteins encoded by three mammalian genes. They bind to and retro-transport endoplasmic reticulum (ER)-resident proteins with a C-terminal Lys-Asp-Glu-Leu (KDEL) sequence or variants thereof. In doing this, KDELR participates in the ER quality control of newly synthesized proteins and the unfolded protein response. The binding of KDEL proteins to KDELR initiates signaling cascades involving three alpha subunits of heterotrimeric G proteins, Src family kinases, protein kinases A (PKAs), and mitogen-activated protein kinases (MAPKs). These signaling pathways coordinate membrane trafficking flows between secretory compartments and control the degradation of the extracellular matrix (ECM), an important step in cancer progression. Considering the basic cellular functions performed by KDELRs, their association with various diseases is not surprising. KDELR mutants unable to bind the collagen-specific chaperon heat-shock protein 47 (HSP47) cause the osteogenesis imperfecta. Moreover, the overexpression of KDELRs appears to be linked to neurodegenerative diseases that share pathological ER-stress and activation of the unfolded protein response (UPR). Even immune function requires a functional KDELR1, as its mutants reduce the number of T lymphocytes and impair antiviral immunity. Several studies have also brought to light the exploitation of the shuttle activity of KDELR during the intoxication and maturation/exit of viral particles. Based on the above, KDELRs can be considered potential targets for the development of novel therapeutic strategies for a variety of diseases involving proteostasis disruption, cancer progression, and infectious disease. However, no drugs targeting KDELR functions are available to date; rather, KDELR has been leveraged to deliver drugs efficiently into cells or improve antigen presentation.

Redirecting Chemotherapeutics to the Endoplasmic Reticulum Increases Tumor Immunogenicity and Potentiates Anti-PD-L1 Therapy

The endoplasmic reticulum (ER) in cancer cells has been considered as a pharmacological target. Still, the effects of a ER-targeted system remain less investigated, due to the fact that most chemo-drugs take actions in the nucleus. Here, it is demonstrated that ER-targeted delivery of doxorubicin (DOX), a typically nucleus-tropic-and-acting agent, attenuates its original effect on cytotoxicity while generating new functions favorable for immune activation. First, a library of DOX derivatives with variable ER-targeting abilities is synthesized. The results reveal that higher ER-targeting efficiency correlates with greater ER stress. As compared with naïve drug, ER-targeted DOX considerably alters the mode of action from nuclear DNA damage-associated cytotoxicity to ER stress-mediated calreticulin exposure. Consequently, ER-targeted DOX decreases cytotoxicity but increases the capability to induce immunogenic cell death (ICD). Therefore, a platform combining naïve and ER-targeted DOX is constructed for in vivo application. Conventional polymer-DOX conjugate inhibits tumor growth by exerting a direct killing effect, and ER-targeted polymer-DOX conjugate suppresses residual tumors by eliciting ICD-associated immunity, together resulting in considerable tumor regression. In addition, simultaneous inhibition of adaptive PD-L1 enrichment (due to negative-feedback to ICD induction) further leads to greater therapeutic outcome. Collectively, ER-targeted therapy can enhance anticancer efficacy by promoting ICD-associated immunotherapy, and potentiating chemotherapy and checkpoint blockade therapy.

Immunogenicity and efficacy of mRNA COVID-19 vaccine MRT5500 in preclinical animal models

Emergency use authorization of COVID vaccines has brought hope to mitigate pandemic of coronavirus disease 2019 (COVID-19). However, there remains a need for additional effective vaccines to meet the global demand and address the potential new viral variants. mRNA technologies offer an expeditious path alternative to traditional vaccine approaches. Here we describe the efforts to utilize an mRNA platform for rational design and evaluations of mRNA vaccine candidates based on the spike (S) glycoprotein of SARS-CoV-2. Several mRNA constructs of S-protein, including wild type, a pre-fusion stabilized mutant (2P), a furin cleavage-site mutant (GSAS) and a double mutant form (2P/GSAS), as well as others, were tested in animal models for their capacity to elicit neutralizing antibodies (nAbs). The lead 2P/GSAS candidate was further assessed in dose-ranging studies in mice and Cynomolgus macaques, and for efficacy in a Syrian golden hamster model. The selected 2P/GSAS vaccine formulation, designated MRT5500, elicited potent nAbs as measured in neutralization assays in all three preclinical models and more importantly, protected against SARS-CoV-2-induced weight loss and lung pathology in hamsters. In addition, MRT5500 elicited T_H1-biased responses in both mouse and non-human primate (NHP), thus alleviating a hypothetical concern of potential vaccine-associated enhanced respiratory diseases known associated with T_H2-biased responses. These data position MRT5500 as a viable vaccine candidate for entering clinical development.

Immunogenicity and efficacy of mRNA COVID-19 vaccine MRT5500 in preclinical animal models

Emergency use authorization of COVID vaccines has brought hope to mitigate pandemic of coronavirus disease 2019 (COVID-19). However, there remains a need for additional effective vaccines to meet the global demand and address the potential new viral variants. mRNA technologies offer an expeditious path alternative to traditional vaccine approaches. Here we describe the efforts to utilize an mRNA platform for rational design and evaluations of mRNA vaccine candidates based on the spike (S) glycoprotein of SARS-CoV-2. Several mRNA constructs of S-protein, including wild type, a pre-fusion stabilized mutant (2P), a furin cleavage-site mutant (GSAS) and a double mutant form (2P/GSAS), as well as others, were tested in animal models for their capacity to elicit neutralizing antibodies (nAbs). The lead 2P/GSAS candidate was further assessed in dose-ranging studies in mice and Cynomolgus macaques, and for efficacy in a Syrian golden hamster model. The selected 2P/GSAS vaccine formulation, designated MRT5500, elicited potent nAbs as measured in neutralization assays in all three preclinical models and more importantly, protected against SARS-CoV-2-induced weight loss and lung pathology in hamsters. In addition, MRT5500 elicited TH1-biased responses in both mouse and non-human primate (NHP), thus alleviating a hypothetical concern of potential vaccine-associated enhanced respiratory diseases known associated with TH2-biased responses. These data position MRT5500 as a viable vaccine candidate for entering clinical development.

DNAJA4 deficiency enhances NF-kappa B-related growth arrest induced by hyperthermia in human keratinocytes

BACKGROUND

Hyperthermia is an effective treatment against cancer and human papillomavirus (HPV) infection. Previous studies have shown that heat shock proteins are crucial to the action of hyperthermia.

OBJECTIVES

To examine the effects of hyperthermia in combination with DNAJA4-deficiency on human keratinocytes and Condyloma acumunatum (CA) tissues.

METHODS

HaCaT cells were subjected to 44°C (compared to 37°C) waterbath for 30min for stimulation. Foreskin or CA tissues obtained from patients undergoing circumcision or pathological examination were bisected and subjected to similar treatments. DNAJA4-knockout (KO) HaCaT cells were generated with CRISPR/Cas9 technology. mRNA and protein expressions were determined using rt-qPCR and western-blotting. Cell cycle distribution, apoptosis and senescence were analyzed by flow cytometry.

RESULTS

DNAJA4 was induced in HaCaT cells, foreskin and CA tissues subjected to hyperthermia at both transcriptional and translational levels. NF-kB,³ was activated by hyperthermia in HaCaT cells, and further enhanced by DNAJA4-deficiency. Transcription of TNF-α⁴; IL-1B,⁵ TNFAIP3⁶ and IL-8⁷ were induced in HaCaT cells subjected to hyperthermia. DNAJA4-knockout promoted transcriptions of TNF-α and IL-1B, whereas decreased that of TNFAIP3 and IL-8. Reduced cell survival, proliferation and viability were demonstrated using flow cytometry and MTS assays. Furthermore, NF-kB inhibitors reversed most of the phenotypes observed.

CONCLUSIONS

Hyperthermia reduced HaCaT cell proliferation and promoted cytokine expressions responsible for anti-viral activity, mainly through a NF-kB dependent pathway. DNAJA4-deficiency enhanced the activation of NF-kB by hyperthermia in HaCaT cells, indicating that DNAJA4 may be a promising therapeutic target for use in the treatment of cutaneous HPV infections.

Dendritic cells treated with HPV16mE7 in a three-dimensional model promote the secretion of IL-12p70 and IFN-γ

Although the human papillomavirus (HPV) DNA therapeutic vaccine represents a promising approach to the prevention and treatment of cervical cancer, the mechanism of the HPV DNA vaccine is poorly understood. Moreover, current strategies have met with only limited success in preclinical and dendritic cell-based (DC-based) clinical research. In addition, two-dimensional (2-D) DC monolayers poorly mimic the physiology function in vivo. We used a three-dimensional (3-D) DC culture model in vitro to explore the immune mechanism of the HPV DNA vaccine. DCs were generated from peripheral blood monocytes with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cells, growing in 3-D collagen gel, were treated with pcDNA3.1-HPV16mE7 in vitro for 48 h. Compared to DCs treated with E7 in a 2-D culture model, the expression of co-stimulatory molecules CD80 and CD40 were significantly increased in the 3-D model (p<0.05), and a remarkable increase of IL-12 p70 was observed. However, we did not detect any obvious change in IL-10 in 3-D culture. In addition, we found that IFN-γ expression increased when HPV16mE7-DC cells were co-cultured with T-cells for 96 h in the 3-D model, and HPV16mE7-DCs stimulated the proliferation of T lymphocytes more efficiently in the 3-D model than in the 2-D model (p<0.05). These results suggest that DCs in 3-D culture model have a notable effect on the enhancement of the HPV16 DNA vaccine's immune reaction and indicate that the DC-based 3-D model is a novel approach to study the HPV vaccine.

Targeting and retention of HPV16 E7 to the endoplasmic reticulum enhances immune tumour protection

The endoplasmic reticulum (ER) is where the major histocompatibility complex (MHC) class I molecules are loaded with epitopes to cause an immune cellular response. Most of the protein antigens are degraded in the cytoplasm to amino acids and few epitopes reach the ER. Antigen targeting of this organelle by Calreticulin (CRT) fusion avoids this degradation and enhances the immune response. We constructed a recombinant adenovirus to express the E7 antigen with an ER-targeting signal peptide (SP) plus an ER retention signal (KDEL sequence). In cell-culture experiments we demonstrated that this new E7 antigen, SP-E7-KDEL, targeted the ER. Infection of mice with this recombinant adenovirus that expresses SP-E7-KDEL showed interferon induction and tumour-protection response, similar to that provided by an adenovirus expressing the E7 antigen fused to CRT. This work demonstrated that just by adding a SP and the KDEL sequence, antigens can be targeted and retained in the ER with a consequent enhancement of immune response and tumour protection. These results will have significant clinical applications.