In vivo antitumor effect of an intracellular single-chain antibody fragment against the E7 oncoprotein of human papillomavirus 16.
Human papillomavirus (HPV)-associated tumors still represent an urgent problem of public health in spite of the efficacy of the prophylactic HPV vaccines. Specific antibodies in single-chain format expressed as intracellular antibodies (intrabodies) are valid tools to counteract the activity of target proteins. We previously showed that the M2SD intrabody, specific for the E7 oncoprotein of HPV16 and expressed in the endoplasmic reticulum of the HPV16-positive SiHa cells, was able to inhibit cell proliferation. Here, we showed by confocal microscopy that M2SD and E7 colocalize in the endoplasmic reticulum of SiHa cells, suggesting that the E7 delocalization mediated by M2SD could account for the anti-proliferative activity of the intrabody. We then tested the M2SD antitumor activity in two mouse models for HPV tumors based respectively on TC-1 and C3 cells. The M2SD intrabody was delivered by retroviral vector to tumor cells before cell injection into C57BL/6 mice. In both models, a marked delay of tumor onset with respect to the controls was observed in all the mice injected with the M2SD-expressing tumor cells and, importantly, a significant percentage of mice remained tumor-free permanently. This is the first in vivo demonstration of the antitumor activity of an intrabody directed towards an HPV oncoprotein. We consider that these results could contribute to the development of new therapeutic molecules based on antibodies in single-chain format, to be employed against the HPV-associated lesions even in combination with other drugs.
Department of Infectious Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, Rome, Italy.
Luisa
L
Accardi
Francesca
F
Paolini
Angela
A
Mandarino
Zulema
Z
Percario
Paola
P
Di Bonito
Valentina
V
Di Carlo
Elisabetta
E
Affabris
Colomba
C
Giorgi
Carla
C
Amici
Aldo
A
Venuti
D000818:Animals; D000914:Antibodies, Viral / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D005260:Female; D015316:Genetic Therapy; D052162:Human papillomavirus 16 / Q000276:immunology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D050725:Papillomavirus E7 Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology; D030361:Papillomavirus Infections / Q000235:genetics / Q000628:therapy* / Q000821:virology; D057127:Single-Chain Antibodies / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000628:therapy* / Q000821:virology
D000914:Antibodies, Viral; D050725:Papillomavirus E7 Proteins; D057127:Single-Chain Antibodies; C059731:oncogene protein E7, Human papillomavirus type 16
E7 oncoprotein; cancer therapy; human papillomaviruses; intrabodies; scFv