title: Antitumor activity of anti-type IV collagenase monoclonal antibody and its lidamycin conjugate against colon carcinoma.
abstract: OBJECTIVE
  Type IV collagenase including MMP-2 and -9 plays an important role in cancer cell invasion and metastasis and is an attractive target for mAb-directed therapy. The immunoreactivity of mAb 3G11, a mAb directed against type IV collagenase in human colorectal carcinomas, was studied by immuno-histochemical (IHC) staining. mAb 3G11 was conjugated to an antitumor antibiotic lidamycin (LDM). The antitumor activity of 3G11-LDM conjugate against colon carcinoma was investigated in mice.
  
  
  METHODS
  ELISA, gelatin zymography, and Western blot assay were used for the biological characterization of mAb 3G11. The immunoreactivity of mAb 3G11 with human colorectal carcinomas was detected by IHC staining. The cytotoxicity of LDM and 3G11-LDM conjugate to human colon carcinoma HT-29 cells was examined by clonogenic assay and MTT assay. The therapeutic effect of conjugate 3G11-LDM was evaluated with colon carcinoma 26 in mice.
  
  
  RESULTS
  As shown in ELISA, mAb 3G11 reacted specifically with type IV collagenase, while 3G11-LDM conjugate also recognized specifically its respective antigen. In IHC assay, mAb 3G11 showed positive immunoreactivity in most cases of colorectal carcinoma, and negative immunoreactivity in the adjacent non-malignant tissues. By gelatin zymography, the inhibition effect of mAb 3G11 on the secretion activity of type IV collagenase was proved. In terms of IC50 values in MTT assay, the cytotoxicity of LDM to human colon carcinoma HT-29 cells was 10,000-fold more potent than that of mitomycin C (MMC) and adriamycin (ADM). 3G11-LDM conjugate also displayed extremely potent cytotoxicity to human colon carcinoma HT-29 cells with an IC50 value of 5.6 x 10(-19) mol/L. 3G11-LDM conjugate at the doses of 0.05 and 0.1 mg/kg inhibited the growth of colon carcinoma 26 in mice by 70.3 and 81.2%, respectively.
  
  
  CONCLUSIONS
  mAb 3G11 is immunoreactive with human colorectal carcinoma and its conjugate with LDM is highly effective against colon carcinoma in mice.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing 100050, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Yun-Hong
authors.initials: YH
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Feng-Qiang
authors.initials: FQ
authors.lastname: Wang
authors.forename: Bo-Yang
authors.initials: BY
authors.lastname: Shang
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Zhen
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D024141:Collagen Type IV / Q000276:immunology*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000276:immunology; D053281:Enediynes; D005354:Fibrosarcoma; D019073:HT29 Cells; D006801:Humans; D018796:Immunoconjugates / Q000494:pharmacology; D066298:In Vitro Techniques; D008113:Liver Neoplasms; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D000617:Aminoglycosides; D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; D024141:Collagen Type IV; D053281:Enediynes; D018796:Immunoconjugates; C058024:C 1027