[Experimental study of combined target treatments using PYM-BAC5 and 131I-BAC5 to nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Combined therapy has been advocated for modern tumor treatment; the combined target therapy is a valuable research direction. Based on the previous research of nasopharyngeal carcinoma (NPC) radioimmunotherapy, this experiment was designed to develop two immunoconjugates of the monoclonal antibody BAC(5):PYM-BAC(5) and (131)I-BAC(5), and to assess the inhibition effects of their combined treatment on the NPC CNE-2 cells cultured in vitro. METHODS: Dextran T40 was used as media to link PYM and BAC(5). The conjugate PYM-BAC(5) was identified by testing its immunoactivity and the inhibition to mycobacterium. BAC(5) was labeled with (131)I by Chloramin-T method. Five experimental groups were set up:(1)PYM-BAC(5) group, (2)free PYM group, (3)(131)I-BAC(5) group, (4)(131)I-mIgG group, (5)the combined target treatment group ( (131)I-BAC(5)+PYM-BAC(5)). The antitumor effects of the five groups were assessed with MTT method. RESULTS: The 50% inhibition doses(IC(50)) of PYM-BAC(5) group and PYM group were 46.57 microg/ml and 316.7 microg/ml, respectively. The IC(50) of (131)I-BAC(5) group and (131)I-mIgG group to CNE2 were 4.42 x 10(5) Bq/ml and >11.1 x 10(5) Bq/ml,respectively. In the combined target treatment group(PYM-BAC(5)+(131)I-BAC(5)),the IC(50) of PYM-BAC(5) was 7.01 microg/ml and of (131)I-BAC(5) was 0.54 x 10(5) Bq/ml, which much less than other separate treatment groups. CONCLUSION: The inhibition effects of the target treatment ((131)I-BAC(5) and PYM-BAC(5)) on the NPC CNE-2 cells are stronger than non-target treatment (free PYM and (131)I-BAC(5)). The combined target treatment of the two immune ((131)I-BAC(5)+PYM-BAC(5)) conjugates gets stronger inhibition effects than their separate treatment.