CpG oligodeoxynucleotides augment antitumor efficacy of folate receptor α based DNA vaccine

Cytosine-phosphate-guanine oligodeoxynucleotides regulate the cell cycle, apoptosis, and steroidogenesis of mouse ovarian granulosa cells by targeting inhibin alpha (1 ~ 32) fragments

Cytosine-phosphate-guanine oligodeoxynucleotides (CpG-ODNs), which exist in vertebrate, bacterial, and viral genomes, are regarded as strong immune adjuvants. To date, the biological activities of CpG-ODNs in reproduction remain unknown. Here, we investigated the effects of CpG-ODNs on the cell cycle, apoptosis, and steroidogenesis in mouse granulosa cells (mGCs), in combination with inhibin alpha (1 ~ 32) fragments. mGCs were transfected with pEGFP (containing green fluorescent protein, as a control), pEGISI (containing inhibin alpha (1 ~ 32) fragments), or pEGISI-CpG-ODNs (containing inhibin alpha (1 ~ 32) fragments and CpG-ODNs motifs) plasmid for 48 h in vitro. Our results showed that the mRNA and protein expression levels of inhibin alpha were downregulated in mGCs transfected with pEGISI-CpG-ODNs, compared to those transfected with pEGISI. Flow cytometry demonstrated that pEGISI-CpG-ODNs transfection promoted cell proliferation (for example, increasing the number of cells in S and G2 phases) and decreased apoptosis, compared to pEGISI transfection. The present study also indicated that the expression of cell cycle-related genes (cyclin D2, cyclin D3, cyclin E1, Cdk2, and Cdk6) was increased, while the expression of apoptosis-related factors (Fas, FasL, caspase-8, and caspase-3) decreased after pEGISI-CpG-ODNs treatment. Additionally, pEGISI-CpG-ODNs reversed the effect of pEGISI on the secretion of estradiol in mGCs, which was further validated by upregulating the levels of its synthesis-related factors (StAR, Cyp11a1, and 17β-HSD II). Nevertheless, pEGISI-CpG-ODNs or pEGISI did not affect the concentration of progesterone nor changed the expression levels of its synthesis-related factors (3β-HSD I and Cyp19a1). In conclusion, this study demonstrated that CpG-ODNs may affect the cell cycle, apoptosis, and steroidogenesis by targeting the effects of inhibin alpha (1 ~ 32) fragments, supporting the potential role of CpG-ODNs in the development of granulosa cells.

Strategies in DNA vaccine for melanoma cancer

According to reports of the international agency for cancer on research, although malignant melanoma shows less prevalence than nonmelanoma skin cancers, it is the major cause of skin cancer mortality. Given that, the production of effective vaccines to control melanoma is eminently required. In this regard, DNA-based vaccines have been extensively investigated for melanoma therapy. DNA vaccines are capable of inducing both cellular and humoral branches of immune responses. These vaccines possess some valuable advantages such as lack of severe side effects and high stability compared to conventional vaccination methods. The ongoing studies are focused on novel strategies in the development of DNA vaccines encoding artificial polyepitope immunogens based on the multiple melanoma antigens, the inclusion of molecular adjuvants to increase the level of immune responses, and the improvement of delivery approaches. In this review, we have outlined the recent advances in the field of melanoma DNA vaccines and described their implications in clinical trials as a strong strategy in the prevention and control of melanoma.

Non-viral COVID-19 vaccine delivery systems

The novel corona virus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the globe at a formidable speed, causing tens of millions of cases and more than one million deaths in less than a year of its report in December 2019. Since then, companies and research institutions have raced to develop SARS-CoV-2 vaccines, ranging from conventional viral and protein-based vaccines to those that are more cutting edge, including DNA- and mRNA-based vaccines. Each vaccine exhibits a different potency and duration of efficacy, as determined by the antigen design, adjuvant molecules, vaccine delivery platforms, and immunization method. In this review, we will introduce a few of the leading non-viral vaccines that are under clinical stage development and discuss delivery strategies to improve vaccine efficacy, duration of protection, safety, and mass vaccination.

DNA vaccine encoding OmpA and Pal from Acinetobacter baumannii efficiently protects mice against pulmonary infection

Acinetobacter baumannii (A. baumannii) is an opportunistic pathogen that causes serious infections in the lungs, blood, and brain in critically ill hospital patients, resulting in considerable mortality rates every year. Due to the rapid appearance of multi-drug resistance or even pan-drug resistance isolates, it is becoming more and more difficult to cure A. baumannii infection by traditional antibiotic treatment, alternative strategies are urgently required to combat A. baumannii infection. In this study, we developed a DNA vaccine encoding two antigens from A. baumannii, OmpA and Pal, and the immunogenicity and protective efficacy was further evaluated. The results showed that the DNA vaccine exhibited significant immune protective efficacy against acute A. baumannii infection in a mouse pneumonia model, and cross protective efficacy was observed when immunized mice were challenged with clinical strains of A. baumannii. DNA vaccine immunization induced high level of humoral response and a mixed Th1/Th2/Th17 cellular response, which protect against lethal bacterial challenges by decreased bacterial loads and pathology in the lungs, and reduced level of inflammatory cytokines expression and inflammatory cell infiltration in BALF. These results demonstrated that it is possible to prevent A. baumannii infection by DNA vaccine and both OmpA and Pal could be serve as promising candidate antigens.

Identification of a peptide for folate receptor alpha by phage display and its tumor targeting activity in ovary cancer xenograft

The expression level of folate receptor alpha (FRα) is located highly rate in ovarian cancer though it is remained absent in normal tissues. This highly tumor restricted expression profile makes FRα a promising target for tumor therapy and diagnosis. In this research we report a FRα binding peptide C7(Met-His-Thr-Ala-Pro-Gly-Trp-Gly-Tyr-Arg-Leu-Ser) discovered by phage display and this peptide showed specific binding to FRα expressing cells by cell ELISA and flow cytometry. Tumor targeting ability of C7 was proved in vivo by both phage homing experiment and fluorescence imaging. C7 can be internalized by SKOV3 cells and its affinity to FRα was determined by MST. The molecular recognition was revealed by structure modeling, suggesting its binding mode with FRα.

MUC1- and Survivin-based DNA Vaccine Combining Immunoadjuvants CpG and interleukin-2 in a Bicistronic Expression Plasmid Generates Specific Immune Responses and Antitumour Effects in a Murine Colorectal Carcinoma Model

DNA vaccination is a promising cancer treatment due to its safety, but poor immunogenicity limits its application. However, immunoadjuvants, heterogeneous prime-boost strategies and combination with conventional treatments can be used to improve the antitumour immune effects. A CpG motif and interleukin-2 (IL-2) cytokine are often used as adjuvants. In this study, a DNA vaccine containing a CpG motif was constructed to evaluate its adjuvant effect. The results show that the cytotoxicity of the DNA vaccine was increased fivefold, and survival lifetime was prolonged twofold by the CpG motif adjuvant. To simplify the industrial production process, a bicistronic plasmid was constructed to carry the fusion genes of survivin/MUC1 (MS) and IL-2 and with a CpG motif in its backbone. The results showed that the antitumour effect of the bicistronic vaccine was the same as that of the two vaccine co-injected regime. Furthermore, the vaccine could suppress metastatic tumour foci by 69.1% in colorectal carcinoma-bearing mice. Moreover, the vaccine induced survivin- and MUC1-specific immune responses in splenocytes and induced the immune promoting factor CCL-19 and GM-CSF upregulated, while metastatic-associated factor MMP-9 and immunosuppressing factor PD-L1 downregulated in tumour tissue. When combining the vaccine with the chemotherapy drug oxaliplatin, the survival was prolonged by about 2.5-fold. In conclusion, the DNA vaccine containing a CpG motif in bicistronic form showed good effects on colorectal cancer by inhibiting both tumour growth and metastasis, and combination with oxaliplatin could improve its antitumour effects.