Study Of Alarmin-expressing Lentiviral Vaccine For Immunotherapy In Hepatocellular Carcinoma

Hepatocellular carcinoma(HCC)is a devastating malignancy with high mortality.Resection has been extensively applied in the clinic but it is only applicable to 10-20%HCC patients.Although different strategies to overcome the physiological barriers and drug resistance are under close scrutiny,there is no effective treatment available in the clinic.Immunotherapy,particularly for(Alpha-fetoprotein)AFP-based immunotherapy,has shown promises but with limited effects.Lentivirus is superior to adenovirus and adenovirus-associated virus in transducing non-replicating cells such as dendritic cells(DCs).Thus,lentivirus has been widely employed in gene therapy and immunotherapy for a myriad of diseases with the first lentivirus-transduced cell therapy approved in 2017.The tenacity of HCC necessitates enhancement of AFP-based lentiviral vaccine immunogenicity which is critical for the clinical use and success,thus immunoadjuvants have been under close scrutiny.In particular,the high mobility group nucleosome binding domain protein 1(HMGN1)has been effective in melanoma,thymoma and colon cancer immunotherapy.However,the potential of HMGN1 in augmenting AFP-specific antitumor immune response in HCC remains elusive.Here,we investigated whether direct fusion of HMGN1 and AFP with the insulin signal peptide for extracellular secretion packaged into lentivirus(Lenti-HA)can trigger stronger antitumor immunity in different HCC mouse models.Covalent linkage of HMGN1 to a tumor-associated antigen was shown to improve antigen-specific immune responses and immunoprotection.Also to further validate its clinical applicability,we tested the antitumor effect of Lenti-HA in human cells in vitro.The results demonstrated that lentivirus encoding the fusion protein of HMGN1and AFP enables augmentation of the antigen-specific antitumor immunity in different HCC mice and human cells in vitro.Importantly,significantly higher antitumor activities were achieved by incorporating HMGN1 into lentiviral vaccines across different HCC mice,particularly in autochthonous HCC mice,a model commonly used for closely mimicking patient HCC.Lenti-HA significantly improved the immune state and tumor microenvironment in autochthonous HCC mice and the enhanced antitumor immunity is likely due to greater homing capacity and activation of DCs conferred by HMGN1.Detailed calibration of different doses of Lenti-HA in comparison with Lenti-AFP revealed that HMGN1 can significantly reduce the effective dose required for Lenti-AFP by at least 6-fold.Besides CD8~+T cells,memory T cells and NKs were also shown to be elevated in blood from Lenti-HA-treated autochthonous HCC mice,implying that these effector cells also contribute to the enhanced antitumor effect elicited by Lenti-HA.In summary,our study demonstrates that HMGN1 is an effective immunoadjuvant and can significantly augment AFP-specific antitumor immune response in different HCC mice and in human cells in vitro,and thus provides a new treatment option for HCC.