Inhibiting autophagy potentiates the antitumor efficacy ofEuphorbia royleanafor canine mammary gland tumors

Abstract

Background Canine mammary gland tumors (cMGTs) are the most common neoplasms in intact female canines and viewed as a suitable model for studying human breast cancers.Euphorbia royleanahas been reported to have a variety of antitumor efficacies. We have prepared the crude extracts ofE. royleanain ethanol and hexane solvents to evaluate the anti-tumor effects for cMGT in vitro and in vivo. Results The results showed thatE. royleanacould inhibit cell proliferation and colony formation in cMGT cells. The suppression of tumor cell growth resulted from necrosis and cell cycle arrest. Moreover, autophagy appears to play a critical role inE. royleana-mediated cell death by triggering cell apoptosis. The in vivo results also revealed thatE. royleanatreatment could reduce the size of solid tumors while exhibiting low toxicity in cMGT-bearing nude mice. Conclusions The anti-tumor mechanisms ofE. royleanawere firstly verified to show it would cause autophagic cell death, apoptosis, and cell cycle arrest in canine mammary tumor cells. The in vitro and in vivo findings in the present study revealedE. royleanahas potential anticancer effects for the treatment of canine mammary gland tumors.