Anti-cancer activity of anti-p185HER-2 ricin A chain immunotoxin on gastric cancer cells.
OBJECTIVE
Overexpression of the human epidermal growth factor receptor 2 (HER-2) protein has been detected in gastric cancer and has been associated with an unfavorable prognosis. We investigated the anti-cancer effects of anti-p185(HER-2) ricin A chain (RTA) immunotoxin, alone or in combination with 5-flurouracil on SGC7901-HER-2+ cells.


METHODS
SGC7901-HER-2+ cells were obtained by transfecting SGC7901 cells with HER-2-pcDNA3.1. Anti-p185(HER-2)-RTA was prepared by chemical conjugation of anti-HER-2 monoclonal antibody (mAb) and RTA. The SGC7901-HER-2+ cells were incubated with RTA, anti-p185(HER-2)-RTA, and/or 5-flurouracil. The effects of drugs on cells were evaluated by MTT assay and Annexin V-fluorescein isothiocyanate and propidium iodide double staining flow cytometry. The expression of caspase-3, caspase-9, cyclooxygenase-2, and nuclear factor-kappaB/p65 were assayed by western blot. SGC7901-HER-2+ cells were transplanted into BALB/c nude mice to produce solid tumors in an attempt to study the immunotoxin activity in vivo.


RESULTS
In vitro, anti-p185(HER-2)-RTA inhibited cell growth and induced apoptosis in SGC7901-HER-2+ cells. Anti-p185(HER-2)-RTA enhanced caspase-3 and caspase-9 activity, while downregulating the expression of cyclooxygenase-2 and nuclear factor-kappaB/p65. Its combination with 5-flurouracil further inhibited the growth of SGC7901-HER-2+ cells. In vivo, our data showed that anti-p185(HER-2)-RTA significantly inhibited the growth of SGC7901-HER-2+ cells-transplanted tumors.


CONCLUSIONS
Anti-p185(HER-2)-RTA inhibits the growth of SGC7901-HER-2+ cells. The effect may be related to the activation of caspase-3 and caspase-9 and inhibition of cyclooxygenase-2 and nuclear factor-kappaB/p65. Anti-p185(HER-2)-RTA plus 5-FU enhance anti-cancer activity, suggesting useful clues for further study for the treatment of HER-2 positive gastric cancers.
Zhou
Xin-Xin
XX
Department of Gastroenterology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
Ji
Feng
F
Zhao
Jing-Li
JL
Cheng
Lin-Fang
LF
Xu
Cheng-Fu
CF
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005472:Fluorouracil / Q000494:pharmacology; D006801:Humans; D000922:Immunotoxins / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000276:immunology*; D012276:Ricin / Q000494:pharmacology*; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D013997:Time Factors; D051996:Transcription Factor RelA / Q000378:metabolism; D014162:Transfection; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D000911:Antibodies, Monoclonal; D000964:Antimetabolites, Antineoplastic; D053148:Caspase 3; D053453:Caspase 9; D051546:Cyclooxygenase 2; D005472:Fluorouracil; D000922:Immunotoxins; D018719:Erb-b2 Receptor Tyrosine Kinases; D012276:Ricin; D051996:Transcription Factor RelA; C498143:RELA protein, human; C496540:PTGS2 protein, human; C505407:CASP3 protein, human; C506433:CASP9 protein, human