Table 3.

Preclinical Studies of DNA-Based Cancer Vaccines in Murine Models as a part of new vaccine discovery and development

Sr No	Murine model and cancer-type	Treatment regimen	Critical findings	References
1	C57BL/6 mice Cervical cancer (TC-1 cells)	DNA Vaccine: HPV plasmid encoding E6 and E7 antigens Combination therapy: pVAX1-ISG15 encoding an optimized mouse adjuvant ISG15	Strong immune response was observed with an increase in IFN-γ secretion	[153]
2	BALB/c mice Murine breast cancer (D2F2 cells)	DNA Vaccine: pVAX-E2A, encoding Her2/neu antigen Combination therapy: pVAX-CCL4, encoding CCL4, chemoattractant for immune effector cells	Combination therapy improved tumor protection. Also, CCL4 produced a Th1 anti-Her2/neu response	[154]
3	BALB/c mice Murine breast cancer (4 T1 cells)	DNA Vaccine: CpVR-FAP, encoding fibroblast associated protein (FAP) Combination therapy: Cyclophosphamide, chemotherapy agent	Combination therapy elevated median survival time of mice	[155]
4	BALB/c mice Colon cancer (CT26/HER2 cells)	DNA Vaccine: pVAX1-HER2, coding HER2 antigen Combination therapy: Gemcitabine, chemotherapy agent; anti-Gr1 antibody; anti-PD-L1 Ab	Combination of vaccine + anti-PD-L1 Ab failed to delay tumor growth. The addition of anti-Gr1 or gemcitabine delayed tumor growth	[156]
5	DBA/2 mice Mastocytoma (P815 cells)	DNA Vaccine: Optimized pVAX2-P1A vaccine, encoding P815A Combination therapy: Anti-CTLA4, anti-PD1	The survival rate reached to 90%. IL-12 production increased and metastasis formation decreased	[157]
6	HHDII-DR1 mice Sarcoma	DNA Vaccine: SSX2-optimized vaccine, encoding modified cancer testis antigen Combination therapy: Ab anti-PD-1/L1	Increase of PD-L1 expression on tumor cells. CTL from immunized mice expressed more PD-1, increasing the antitumor efficacy of the combination with ICB	[158]
7	C57BL/6 mice Melanoma (B16F10 cells)	DNA Vaccine: pVAX1-MUCI, encoding mucin I glycoprotein Combination therapy: pVAX1-Flt3L, encoding Fms-like tyrosinase 3-ligand	Specific CTL and antibodies were observed and tumor growth suppression was seen	[159]
8	BALB/c mice Colorectal cancer (CT- 26/NIS cells)	DNA Vaccine: pcDNA-hNIS, expressing human sodium/io- dide symporter (hNIS)	Elevation was seen in the IgG2a/IgG1 ratio, and the number of INF-g-secreting cells and IFN-g production increased. Th1 response was demonstrated and tumor growth slowed down	[160]
9	BALB/c mice Murine breast cancer (4 T1 cells)	DNA Vaccine: pVAX1-mCr-1, encoding mouse Cripto-1 oncofetal protein	A protective immune response was observed against cancer stem cells and lung metastasis seemed to be reduced	[161]
10	BALB/c mice Murine breast cancer (4 T1 cells)	DNA Vaccine: CpVR-FAP, encoding FAP	An increase in IL-2 production and a delay of tumor growth was observed. Specific CTL response against FAP was seen	[162]
11	BALB/c mice Kidney cancer (RenCa cells)	DNA Vaccine: pVAX1-G250-F2A-CTLA4, containing the co-expression gene G250-CTLA4, linked by Furin-2A (F2A)	Humoral and cellular-specific immune response against CTLA4 and G250 was observed. The rate of tumor growth reduced and there was an increase in INFγ and IL-4 (Th1/2 response)	[163]