Potent inhibition of human gastric cancer by HER2-directed induction of apoptosis with anti-HER2 antibody and caspase-3 fusion protein.
OBJECTIVE
HER2, an oncogene, has been found to be over-expressed in 10-40% of human gastric carcinomas. The aims of this study were to investigate if a fusion protein consisting of anti-HER2 sFv and constitutively active caspase-3 was capable of inducing apoptosis in HER2-expressing human gastric cancer cells and blocking the growth of human gastric cancer xenografts in nude mice.


METHODS
NIH3T3 cells stably transduced with the pcDNA3.1-HER-PE-CP3 recombinant plasmid containing a secretion signal, a single-chain anti-HER2 monoclonal antibody fragment, a Pseudomonas exotoxin A translocation domain and a constitutively active caspase-3 molecule were used to induce apoptosis in human gastric cancer cells both in vitro and in vivo. Immunofluorescence staining and western blotting were used to examine the expression of the recombinant protein HER-PE-CP3. Apoptosis was determined by flow cytometry and TUNEL assay.


RESULTS
Co-cultivation of HER-PE-CP3/ NIH3T3 with human gastric cancer cells led to internalisation of HER-PE-CP3 and apoptosis in HER2-expressing human gastric cancer cells but not in HER2-negative cancer cells. Inoculation of HER-PE-CP3/NIH3T3 in nude mice resulted in potent inhibition of human gastric cancer xenografts and much prolonged survival time of the tumour-bearing mice compared with the control. Significantly more apoptotic cells were detected in xenografts in mice receiving HER-PE-CP3/NIH3T3 than in control mice.


CONCLUSIONS
The HER-PE-CP3 chimeric molecule could induce selective apoptosis and potent growth inhibition of HER2-positive human gastric cancer cells and might represent a novel HER2-directed treatment option for human gastric cancer.
Zhang
De-Xin
DX
State Key Laboratory of Cancer Biology & Xijing Hospital of Digestive Disease, the Fourth Military Medical University, 15 West Chang-Le Road, Xi'an 710032, PR China.
Zhao
Peng-Tao
PT
Xia
Lin
L
Liu
Li-Li
LL
Liang
Jie
J
Zhai
Hui-Hong
HH
Zhang
Hong-Bo
HB
Guo
Xue-Gang
XG
Wu
Kai-Chun
KC
Xu
Yan-Ming
YM
Jia
Lin-Tao
LT
Yang
An-Gang
AG
Chen
Si-Yi
SY
Fan
Dai-Ming
DM
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000627:therapeutic use; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000494:pharmacology / Q000627:therapeutic use*; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D053148:Caspase 3; D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C508053:ERBB2 protein, human