Exploring baculovirus-mediated gene therapy targeting humanin in experimental CNS tumors

GOTTARDO MARÍA FLORENCIA; ASAD ANTONELA ; SAGRIPANTI SOFÍA; ROMANOWSKI VÍCTOR; MARCHESINI ABRIL; PÉREZ VIDAKOVICS MARÍA LAURA; CANDOLFI MARIANELA; PIDRE MATIAS LUIS; ZUCCATO CAMILA; NICOLA CANDIA ALEJANDRO JAVIER; SEILICOVICH ADRIANA

Barcelona

Congreso; XV National Congress of Spanish Society for Virology (SEV) and 11th International Meeting of Global Virus Network; 2019

Spanish Society for Virology and Global Virus Network

IntroductionAcMNPV, the prototypebaculovirus, does not infect vertebrates, but can efficientlytransduce DNA in a wide variety of cells. Humanin (HN) is amitochondrial-derivedpeptide that plays a cytoprotective role in several cell types andalso promotes autophagy. We have previously shown that inhibition ofendogenous HNr (a rat homolog of human HN) expression inducesapoptosis in a pituitarysomatolactotrope tumor cell line (GH3)using a shRNA against HN/HNr delivered by a recombinant AcMNPV(Ac-shHNr). Ac-shHNr also expresses dTomato as a reporter gene.Moreover, intratumor injection of Ac-shHNr reduced tumor growth ofGH3 mouse tumor models andincreased their survival.In this study we further evaluated the use of AcMNPV for transgenedelivery in tumors of the CNS, i.e.experimental prolactinoma and glioblastoma (GB) by exploringtransduction efficiency, neurotoxicity, apoptosis and autophagyinduction. Materials & MethodsNudemice wereinjected subcutaneously (s.c.) with 3 × 106GH3 cells, and C57BL/6 mice were injected intracraneally (i.c.) with2x104syngeneic GL26 GB cells. Three weeks after inoculation, animals wereinjected intratumorally with 108PFUs of recombinant or control baculovirus for pituitary tumors or109PFUs for glioblastoma. Naïve mice were also injected in the brain toassess neurotoxicity. Transduction efficiency (dTomato), apoptosis(TUNEL) and autophagy induction (immunofluorecence) were assessedafter 5 or 15 days. HN expression and effect on chemosensitivity werealso determined after transduction of GB cells invitro.ResultsWe detected AcMNPV-mediatedexpression of reporter and HN genes in the naïve brain and theintracranial tumors without signs of neurotoxicity. Ac-shHNr inducedapoptosis and increased the sensivity of GB cells to chemotherapeuticdrugs cisplatin and temozolomide. Local injection of Ac-shHNrincreased the apoptotic rate in GH3 tumors. Finally, we determinedthat Ac-shHNr treatment decreased expression levels of LC3 and ATG17,suggesting that Ac-shHNr can also inhibit autophagy in pituitarytumors. Discussion &ConclusionOur results suggest thatsilencing of endogenous HN using baculoviral vectors inducesapoptosis of tumor cells, leading to inhibition of tumor growth.Therefore, the use of baculovirus vectors could be a promisingalternative and a complement for the treatment of tumors of the CNS.p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left; }p.western { font-family: "Calibri", serif; font-size: 11pt; }p.cjk { font-family: "Calibri"; font-size: 11pt; }p.ctl { font-family: "DejaVu Sans", "Verdana"; font-size: 11pt; }a:link { color: rgb(0, 0, 255); }