Anti-tumor activity of baculoviruses displaying and expressing the cancer-specific apoptosis inducing cytokine, Mda-7
Year: 2009
Type: dissertation
Abstract: Recently, it has been widely proposed that cancer could be treated by transferring therapeutic genes or proteins into the cancer tissue by using different viral or non-viral systems. Among the vectors under development is the insect baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), which represents a versatile tool for both mammalian gene delivery and protein display. Due to its low cytotoxicity and innate inability to replicate in mammalian cells, AcMNPV holds potential for in vivo applications. The melanoma differentiation associated gene 7 (Mda-7), in turn, is a novel multifunctional tumor-specific cytokine that suppresses growth and induces apoptosis in numerous human cancer cells. Furthermore, Mda-7 possesses immunomodulatory and anti-angiogenic features, as well as a robust bystander activity. The objectives of this study were to generate and characterize recombinant baculovirus vectors expressing and/or displaying Mda-7, as well as to analyze the anti-tumor activity of these viruses. Two mammalian expression vectors, Ac-Mda-7 and the control virus Ac-Luc, were constructed, expressing Mda-7 or firefly luciferase, respectively. Additionally, by utilizing these vectors as backbones, two surfacemodified viruses, AcMda-7-Luc and AcMda-7-Mda-7, displaying Mda-7 by fusion to the transmembrane anchor of vesicular stomatitis virus G-protein (Mda-7-VSVg) on their surface, were developed. The Mda-7VSVg fusion protein was successfully expressed in insect cells and incorporated into the budded virions of AcMda-7-Luc and AcMda-7-Mda-7 as demonstrated by confocal microscopy and Western blotting. Importantly, analysis by Western blotting and flow cytometry showed no significant differences between the infectivities of the unmodified and the Mda-7-VSVg-displaying viruses. Furthermore, Annexin V-staining and subsequent analysis by flow cytometry revealed clear induction of apoptosis by Ac-Mda-7, AcMda-7-Luc and AcMda-7-Mda-7, but not by the control virus Ac-Luc in human prostate cancer PC-3 cells at 5 days post transduction. These results demonstrate the functionality of baculovirus mediated gene delivery and protein display, highlighting the potential of baculovirus vectors in cancer therapy.
Author: Riikka Kapanen
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
Funder: Suomen Kulttuurirahasto
OpenAlex ID: W2253219954