Electrotransfer of Different Control Plasmids Elicits Different Antitumor Effectiveness in B16.F10 Melanoma

Area of Science:

• Oncology
• Molecular Biology
• Biotechnology

Background:

• Different control plasmids exhibit varying antitumor effects post-gene electrotransfer (GET) in murine models.
• Incomparable results across studies stem from variations in GET protocols, plasmid vectors, and experimental models.

Purpose of the Study:

• To compare the antitumor effectiveness of three distinct control plasmids (pControl, pENTR/U6 scr, pVAX1) using standardized GET parameters.
• To investigate cellular responses, including cell death and the upregulation of cytosolic DNA sensors and cytokines, following GET of these plasmids in B16.F10 melanoma cells and tumors.

Main Methods:

• In vitro cytotoxicity assays and in vivo antitumor efficacy assessments in B16.F10 melanoma models.
• Analysis of cell death mechanisms and quantification of selected cytosolic DNA sensors and cytokine mRNA/protein levels post-GET.
• Standardized GET parameters were applied across all experimental groups.

Main Results:

• All three plasmids induced significant melanoma tumor growth delay, with pVAX1 showing a markedly greater effect than pControl.
• In vivo, while DNA sensors showed no significant upregulation, cytokines IFN-β and TNF-α were elevated after pVAX1 GET.
• In vitro, GET led to overexpression of some cytosolic DNA sensor mRNAs, but without significant differences among the plasmids.

Conclusions:

• Control plasmid choice impacts in vivo antitumor effectiveness in melanoma models, with pVAX1 demonstrating superior performance.
• Cellular responses in vitro did not significantly differ across the tested plasmids, indicating that the tumor microenvironment and plasmid properties are key determinants of in vivo efficacy.