IN-VITRO ANTITUMOR-ACTIVITY OF MIC2 PROTEIN-DOXORUBICIN CONJUGATES

The pseudoautosomal encoded MIC2 glycoprotein is a tumor-associated an tigen of Ewing's sarcoma (ES) and closely related tumors of unknown fu nction. To investigate the use of this protein as selective drug carri er recombinant MIC2 was coupled to doxorubicin by a two step glutarald ehyde method (molar ratio DOX/MIC2 of 32 and 16). The conjugates showe d dose-dependent cytostatic activity against the ES cell line SK-ES1, the peripheral neuroectodermal line KAL and the prostate cancer cell l ine PC-3 concurrent with reduced toxicity against normal lymphoblasts. In comparison to free doxorubicin the MIC2-doxorubicin conjugates exh ibited highest activity against the PC-3 cell line. Confocal microscop y showed intracellular accumulation of MIC2 conjugates.