Momelotinib sensitizes glioblastoma cells to temozolomide by enhancement of autophagy via JAK2/STAT3 inhibition.

Temozolomide (TMZ) is a widely used chemotherapeutic agent for glioblastoma multiforme (GBM). However, chemoresistance to TMZ is still a major obstacle for GBM patients. An abundance of candidates has been reported to improve the chemotherapeutic sensitization of TMZ. In the present study, it was demonstrated that momelotinib (MTB) enhanced the sensitivity of glioma cells to TMZ in vitro, as evidenced by a noticeable decrease in cell growth and a significant increase in apoptosis and autophagy following treatment with the combination of TMZ and MTB compared to TMZ alone. Mechanistically, MTB and TMZ combination treatment reduced U251 cell growth by activating both apoptosis and autophagy pathways. MTB potentiated TMZ to inhibit the phosphorylation of JAK2 and STAT3 in U251 cells, resulting in the inactivation of JAK2/STAT3 signaling pathways. Moreover, we investigated the effect of MTB in xenograft tumor model mice. MTB and TMZ combination reduced tumor weight, decreased the expression of Ki‑67, P62, p‑STAT3 and p‑JAK2, while increased the ratio of LC3‑II/I and the expression of caspase‑3 and Beclin1 in vivo. Importantly, this combination was well tolerated, and caused significant tumor growth inhibition in the GBM xenografts. In summary, the present study provides pharmacological evidence that MTB has potential value in the treatment of GBM.