Truncated TERT mRNA transfected dendritic cells evoke TERT specific antitumor response in vivo

Abstract

Background/aims: To evaluate the antitumor immune response induced by truncated TERT (TERTt) mRNA transfected dendritic cells (DCs) in

Methodology: Truncated mouse TERT sequence (according to mice telomerase reverse transcriptase mRNA 1776bp-2942bp) was cloned from B16 mice melanoma cells and inserted into pBluescript II KS(+) plasmid downstreaming of T7 promoter. The in vitro transcription was performed to prepare TERTt mRNA. The bone marrow-derived DCs isolated from BALB/c or C57B/L mice were electroporated with TERTt mRNA and recruited to immunize syngeneic naive mice respectively. The quantity and cytotoxic activity of tumor specific cytotoxic T lymphocytes (CTLs) in mice spleen were evaluated by using IFN-gamma enzyme-linked immunospot (ELIspot) and LDH release assay. The immunoprophylactic effects induced by TERTt mRNA transfected DC were evaluated in immunized-challenged mouse model.

Results: TERTt was cloned and transcripted into TERTt mRNA in vitro. TERTt mRNA transfected bone marrow-derived DCs were prepared. As shown by transfecting with EGFP mRNA, the DC transfected efficiency is 35.1% and there was a subtle increase of costimulator and MHC-II molecule expression after electroporation. Immunization with TERTt mRNA transfected DCs can induce TERTt and TERT-specific IFN-gamma secreting CTLs in the spleen of immunized mice. The splenocytes isolated from mice immunized with TERTt mRNA transfected DCs showed specific cytotoxic activity against TERTt and TERT-positive target cells. Using a syngeneic cancer mouse model, it was shown that TERTt mRNA transfected DCs vaccination can suppress the growth of TERT-positive tumor inoculation.

Conclusions: TERTt mRNA transfected bone marrow-derived DCs can evoke antitumor immune response in vivo effectively and TERTt can serve as a universal tumor associated antigen to produce DC-based tumor vaccine.