A baculovirus vector for gene therapy of different tumors.

ZUCCATO CAMILA; CANDOLFI MARIANELA; GOTTARDO MARÍA FLORENCIA; ASAD ANTONELA; ROMANOWSKI VÍCTOR; PIDRE MATIAS LUIS; IMSEN MERCEDES; SEILICOVICH ADRIANA

Madison, Wisconsin

Congreso; 36th Annual Meeting American Society for Virology; 2017

Baculoviruses are a family of enveloped DNA viruses pathogenic to invertebrates, infecting primarily insects of the order Lepidoptera. Baculoviruses have supercoiled, double-stranded DNA genomes of approximately 80 to 180 kbp. Autographa californica Multiple Nucleopolyhedrovirus (AcMNPV) is the most used and studied baculovirus and there are many genetic tools to generate recombinant viruses. In addition, AcMNPV is able to transduce mammalian cells, allowing the expression of heterologous genes under the control of mammalian promoters, without causing infection.Humanin (HN) is a 24-amino acid peptide originally isolated from a cDNA library of surviving neurons in Alzheimer´s disease. Both, HN and Rattin (HNr) - a homologous peptide in rat- have cytoprotective action in several cell types including neurons, lymphocytes and testicular germ cells (i). Previously, we showed that HNr is expressed in murine mammary carcinoma cells (4T1) and the GH3 somatolactotrope tumor cells, and that exogenous HN exerts antiapoptotic and mitogenic actions against various insults such as serum deprivation or TNF-α in these cells (ii). In the present study, we evaluated the effect of inhibition of endogenous HNr expression on the apoptosis of 4T1 and GH3 cells using a shRNA against HNr delivered by a recombinant baculovirus AcMNPV (Ac-shHNr).Ac-shHNr was able to transduce GH3 and 4T1 cells with an efficiency higher than 75% and increased apoptosis of tumor cells in vitro. Intratumor injection of Ac-shHNr reduced tumor growth of xenografted GH3 cells in female nude mice and increased survival compared to control baculovirus injection, indicating that endogenous HNr promotes tumor growth.Our results suggest that endogenous HN exerts antiapoptotic effect in tumor cells, and that interfering with HN expression would lead to inhibition of tumor progression. Therefore, the use of baculovirus vectors to block HN might be a promissing alternative for the development of tumor treatment strategies.(i) Yen, K., et al., 2013. J Mol Endocrinol. 50(1): R11-9.(ii) Gottardo MF, et al., 2014. PLoS One 9: e111548