Anti-neoplastic effect of chicken anemia virus VP3 protein (apoptin) in Rous sarcoma virus-induced tumours in chicken.
The anti-neoplastic effect of chicken anemia virus VP3 protein (apoptin) was investigated in vitro in Rous sarcoma virus (RSV)-transformed chicken embryo fibroblast (CEF) cells and in RSV-induced tumours of specific-pathogen-free (SPF) chicks in vivo. The apoptin gene was cloned in the pVAX expression vector and in vitro expression of the recombinant vector pVAX-CAV-VP3 was confirmed. Two groups of SPF chicks, each containing ten chicks, were used. Chicks in groups I and II were inoculated with RSV at 1 day old. Group I served as the control, receiving pVAX vector without insert, and group II received recombinant vector pVAX-CAV-VP3 containing the apoptin gene, on day 10. An in vitro study confirmed that apoptin induced apoptosis in RSV-transformed CEF cells, which was demonstrated by observation of the characteristic changes of apoptosis using the indirect immunofluorescence technique and acridine orange/ethidium bromide staining. In vivo study also indicated that apoptin induced apoptosis and caused tumour regression by an intratumoral-delivery method. Apoptotic changes, such as nuclear condensation, fragmentation of the chromatin and formation of apoptic bodies in the tumour cells, were demonstrated by histopathology and acridine orange/ethidium bromide staining. No apoptotic changes were seen in the tumours of the control group. The results of the present study showed that apoptin had an anti-neoplastic effect in vivo and in vitro in RSV-induced tumours. The anti-neoplastic effect is due to apoptin-induced apoptosis. Further improvements in the dose, delivery method and delivery frequency of the apoptin-expressing recombinant vector could help to develop apoptin as an anti-neoplastic drug.
Natesan
Senthilkumar
S
Molecular Biology Laboratory, Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122 (UP), India.
Kataria
J M
JM
Molecular Biology Laboratory, Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122 (UP), India.
Dhama
K
K
Molecular Biology Laboratory, Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122 (UP), India.
Bhardwaj
N
N
Molecular Biology Laboratory, Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122 (UP), India.
Sylvester
A
A
Molecular Biology Laboratory, Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar, Bareilly 243122 (UP), India.
D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism*; D001358:Avian Sarcoma Viruses / Q000502:physiology*; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002645:Chickens / Q000821:virology; D015870:Gene Expression; D006801:Humans; D011201:Poultry Diseases / Q000473:pathology* / Q000821:virology*; D001357:Sarcoma, Avian / Q000473:pathology* / Q000821:virology*; D013047:Specific Pathogen-Free Organisms
D000970:Antineoplastic Agents; D036022:Capsid Proteins; C091717:VP3 protein, Chicken anemia virus