Additive and antagonist effects of therapeutic gene combinations for suppression of HIV-1 infection.
A previously described Moloney-based vector expressing a double copy anti-tat antisense tRNA (DC-tRNA-AT) (Biasolo et al., 1996. J. Virol. 70, 2154-2161) was modified to increase the copy number of the antisense molecule and to target the intra-cytoplasmic localization of the HIV genome. To this end, an anti-U5 hammerhead ribozyme, engineered as a hybrid small adenoviral VAI RNA (VAIalpha), was inserted into the vector as a single molecule or in combination with the double copy anti-tat sequence. The retroviral vector expressing only VAIalpha (DC-VAIalpha) inhibited HIV-1 replication to an extent comparable to that of DC-tRNA-AT. A more effective inhibition was produced by the vector expressing multiple copies of the anti-tat antisense (DC-6tRNA-AT). This higher effectiveness correlated with anti-tat stochiometry, i.e. with the absolute number of therapeutic molecules being produced on a per cell basis at the steady state. Surprisingly, when the tRNA-AT and VAIalpha genes were combined in the same vector (DC-AT-VAIalpha), an enhancement of viral replication was noticed. This study indicates that it is possible to potentiate the antiviral activity of a retroviral vector by increasing the steady-state level of the therapeutic molecule. Results also show that the combined expression of two singularly active therapeutic RNAs can have antagonistic rather than synergistic effects.
Gennari
Francesca
F
Department of Histology, Microbiology and Medical Biotechnologies, University of Padova, via A. Gabelli 63, 35121, Padova, Italy.
Biasolo
Maria Angela
MA
Cancellotti
Enrico
E
Radaelli
Antonia
A
De Giuli Morghen
Carlo
C
Bozzoni
Irene
I
Cereda
Paolo Martino
PM
Mengoli
Carlo
C
Palù
Giorgio
G
Parolin
Cristina
C
D000256:Adenoviridae / Q000235:genetics; D015696:Gene Products, tat / Q000235:genetics; D015316:Genetic Therapy; D005822:Genetic Vectors; D015497:HIV-1 / Q000502:physiology; D006801:Humans; D019169:Jurkat Cells; D016372:RNA, Antisense / Q000737:chemistry / Q000235:genetics; D016337:RNA, Catalytic / Q000235:genetics; D012190:Retroviridae / Q000235:genetics; D013223:Statistics as Topic; D014162:Transfection; D014779:Virus Replication; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D016372:RNA, Antisense; D016337:RNA, Catalytic; C427204:hammerhead ribozyme; C434423:ribozyme UV5; D054322:tat Gene Products, Human Immunodeficiency Virus