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Antibody-Targeted Chemotherapy with the Calicheamicin Conjugate hu3S193- N -Acetyl γ Calicheamicin Dimethyl Hydrazide Targets Lewisy and Eliminates Lewisy-Positive Human Carcinoma Cells and Xenografts

2004; American Association for Cancer Research; Volume: 10; Issue: 13 Linguagem: Inglês

10.1158/1078-0432.ccr-04-0037

1557-3265

Erwin R. Boghaert, Latha Sridharan, Douglas Armellino, Kiran Khandke, John F. DiJoseph, Arthur Kunz, Maureen Dougher, Fan Jiang, Lyka B. Kalyandrug, Philip R. Hamann, Philip Frost, Nitin K. Damle,

Cancer therapeutics and mechanisms

Abstract Purpose: Linking a cytotoxic anticancer drug to an antibody that recognizes a tumor-associated antigen can improve the therapeutic index of the drug. We asked whether a conjugate of the cytotoxic antibiotic N-acetyl γ calicheamicin dimethyl hydrazide (CalichDMH) and an antibody recognizing Lewisy (Ley) antigen could eliminate carcinomas that express Ley. Because Ley is highly expressed on carcinomas of colon, breast, lung, ovary, and prostate, a CalichDMH conjugate targeting Ley could provide a treatment option for various cancers. Experimental Design: The humanized anti-Ley antibody hu3S193 was conjugated to CalichDMH via the bifunctional AcBut linker. Selectivity and avidity of the conjugate (hu3S193-CalichDMH) for Ley-BSA or Ley+ cells was tested by BIAcore or flow cytometry. Cytotoxicity of hu3S193-CalichDMH was compared with toxicity of a control conjugate on monolayers of Ley+ and Ley− carcinoma cells. Inhibition of tumor growth by hu3S193-CalichDMH was assessed on three types of s.c. xenografts. Results: Hu3S193-CalichDMH had similar selectivity as hu3S193. The conjugate had lower affinity for Ley-BSA but not for Ley+ cells. When tested on monolayers of human Ley+ carcinoma cells, hu3S193-CalichDMH was more cytotoxic than a control conjugate. This difference in efficacy was not noted on Ley− cells. Efficacy of hu3S193-CalichDMH depended on the expression of Ley and on the sensitivity of the cells to CalichDMH. In vivo, hu3S193-CalichDMH inhibited growth of xenografted human gastric (N87), colon (LOVO), and prostate carcinomas (LNCaP). When used against N87 xenografts, hu3S193-CalichDMH arrested tumor growth for at least 100 days. Conclusion: Hu3S193-CalichDMH can specifically eliminate Ley+ tumors. These results support development of this conjugate for treatment of carcinomas.