Secreted antibody/granzyme B fusion protein stimulates selective killing of HER2-overexpressing tumor cells.
Targeted cell killing is required for effective treatment of cancers. We previously described the generation of a chimeric immunocasp-3 protein and its potent selective antitumor activity (Jia, L. T., Zhang, L. H., Yu, C. J., Zhao, J., Xu, Y. M., Gui, J. H., Jin, M., Ji, Z. L., Wen, W. H., Wang, C. J., Chen, S. Y., and Yang, A. G. (2003) Cancer Res. 63, 3257-3262). Here we extend the repertoire of another chimeric pro-apoptotic protein immunoGrB, which comprises an anti-HER2 single-chain antibody, a Pseudomonas exotoxin A translocation domain and active granzyme B. Human lymphoma Jurkat cells transfected with the immunoGrB gene expression vector were able to produce and secrete the chimeric protein. The immunoGrB molecule selectively recognized and destroyed HER2-overexpressing tumor cells both in vitro and in nude mouse after intramuscular injection of the immunoGrB expression plasmid. Further in vivo study showed that intravenous administration of immunoGrB gene-modified lymphocytes led to suppression of HER2-overexpressing tumor growth and prolonged animal survival because of continuous secretion of immunoGrB molecules into blood and lymph fluid. These results demonstrate that the chimeric immunoGrB molecule, which is capable of antibody-directed targeting and granzyme B-mediated killing, has therapeutic potential against HER2 tumors, especially in cases in which caspase-dependent apoptosis is inhibited.
Departments of Biochemistry and Molecular Biology and Immunology, the Fourth Military Medical University, Xi'an 710032, China.
Jing
J
Zhao
Li-Hong
LH
Zhang
Lin-Tao
LT
Jia
Li
L
Zhang
Yan-Ming
YM
Xu
Zhi
Z
Wang
Cui-Juan
CJ
Yu
Wei-Dan
WD
Peng
Wei-Hong
WH
Wen
Cheng-Ji
CJ
Wang
Si-Yi
SY
Chen
An-Gang
AG
Yang
D000818:Animals; D000906:Antibodies / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D053804:Granzymes; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000633:toxicity*; D012697:Serine Endopeptidases / Q000633:toxicity*; D014162:Transfection; D014183:Transplantation, Heterologous
D000906:Antibodies; D053804:Granzymes; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; C509213:GZMB protein, human; C509214:Gzmb protein, mouse