PEG-transferrin conjugated TRAIL (TNF-related apoptosis-inducing ligand) for therapeutic tumor targeting

다국어 초록 (Multilingual Abstract)

Transferrin (Tf) is considered an effective tumor-targeting agent, and PEGylation effectively prolongs in vivo pharmacokinetics by delaying excretion via the renal route. The authors describe the active tumor targeting of long-acting Tf-PEG-TNF-related apoptosis-inducing ligand conjugate (Tf-PEG-TRAIL) for effective cancer therapy. Tf-PEG-TRAIL was prepared using a two-step N-terminal specific PEGylation procedure using different PEGs (Mw: 3.4, 5, 10kDa). Eventually, only 10kDa PEG was linked to Tf and TRAIL because TRAIL (66kDa) and Tf (81kDa) were too large to link to 3.4 and 5kDa PEG. The final conjugate Tf-PEG<SUB>10K</SUB>-TRAIL was successfully purified and characterized by SDS-PAGE, western blotting. To determine the specific binding of Tf-PEG<SUB>10K</SUB>-TRAIL to Tf receptor, competitive receptor binding assays were performed on K 562 cells. The results obtained demonstrate that the affinity of Tf-PEG<SUB>10K</SUB>-TRAIL for Tf receptor is similar to that of native Tf. In contrast, PEG<SUB>10K</SUB>-TRAIL demonstrated no specificity. Biodistribution patterns and antitumor effects were investigated in C57BL6 mice bearing B16F10 murine melanomas and BALB/c athymic mice bearing HCT116. Tumor accumulation of Tf-PEG<SUB>10K</SUB>-TRAIL was 5.2 fold higher (at 2h) than TRAIL, because Tf-PEG<SUB>10K</SUB>-TRAIL has both passive and active tumor targeting ability. Furthermore, the suppression of tumors by Tf-PEG<SUB>10K</SUB>-TRAIL was 3.6 and 1.5 fold those of TRAIL and PEG<SUB>10K</SUB>-TRAIL, respectively. These results suggest that Tf-PEG<SUB>10K</SUB>-TRAIL is a superior pharmacokinetic conjugate that potently targets tumors and that it should be viewed as a potential cancer therapy.