Comparison of the Inhibitory Effect of PEG-Liposomal and Conventional Doxorubicin on Migration and Extravasation Efficacy on Canine Osteosarcoma Cell Line- in Vitro and Ex Ovo Studies.
Abstract The chick chorioallantoic membrane (CAM) assay has long been used to study the effects of drugs on angiogenesis or evaluate cancer cell invasiveness by quantifying in vivo rates of cancer cell extravasation. Extravasation plays a crucial role in the metastatic cascade, whereby circulating cancer cells derived from the primary tumor cross the endothelial barrier to reach the target metastatic site. Accordingly, we adapted an ex ovo model to study the anti-extravasation efficiency of anticancer drugs. The drugs investigated include conventional and PEG-liposomal doxorubicin. The conventional form is commonly used in chemotherapy protocols for canine appendicular osteosarcoma (OSA), although it has no specific biodistribution and a low therapeutic index. For this reason, this study compared the effects of conventional and PEG-liposomal doxorubicin on cytotoxicity and migration inhibition in the in vitro environment. Cytotoxicity was evaluated by the MTT assay, Annexin V staining and the Draq 7 test; the inhibition of migration was analyzed using the scratch assay test. Moreover the inhibitory effect of study drugs on cancer cell extravasation was analyzed in the in vivo conditions, on the ex ovo model. The results of experiments performed showed that PEG-liposomal doxorubicin has a higher inhibitory effect on the in vitro migration of canine OSA (p ≤ 0.05). Ex ovo research revealed both drugs elicited a high efficiency for inhibiting the extravasation of canine OSA (p< 0.0001). Therefore PEG-liposomal doxorubicin may be considered as a potentially useful anti-metastatic agent in canine osteosarcoma due to its inhibitory effect on both the migration and extravasation of the D-17 cell line.