Malignant melanoma (MM) is one of the most malignant
tumors and has a very poor prognosis. However, there are no effective drugs to treat this disease. As a kind of
iron flavin dependent
enzyme,
dihydroorotate dehydrogenase (
DHODH, EC 1.3.3.1) is the fourth and a key
enzyme in the de novo biosynthesis of
pyrimidines. Herein, we found that
DHODH inactivation/deficiency inhibited
melanoma cell proliferation, induced cell cycle arrest at S phase and lead to autophagy in human
melanoma cells. Meanwhile,
leflunomide treatment induced cell apoptosis and deficiency of
DHODH sensitized cells to
drug-induced apoptosis in BCL-2 deficient
melanoma cells, while not in BCL-2 abundant
melanoma cells. Then we found that BCL-2 could rescue apoptosis induced by
DHODH inactivation/deficiency. Moreover, BCL-2 also showed to promote cell cycle arrest and to inhibit autophagy induced by
leflunomide. To explore the mechanisms underlying autophagy induced by
DHODH inhibition, we found that AMPK-Ulk1 axis was activated in this process. Besides, JNK was phosphorylated and activated to phosphorylate BCL-2, which abrogated the interaction between BCL-2 and
Beclin1 and then abolished autophagy. Our findings provided evidences for the potential of
DHODH used as a
drug target for
melanoma treatment.