Figure 5.

Doxycycline significantly enhances the inhibitory effects of temozolomide in glioblastoma in vitro and in vivo. Combination of doxycycline and temozolomide is more superior in inhibiting proliferation (A) and inducing apoptosis (B) than single drug alone in glioblastoma cells. The concentrations of doxycycline and temozolomide used in combination studies were 10 μM and 5 μM, respectively. (C) Combination of doxycycline and temozolomide further inhibits A172 tumor growth in SCID mice compared to single drug alone. 100 mg/kg intraperitoneal doxycycline and 20 mg/kg oral temozolomide or combination of both was given once per day for 30 days. * p<0.05 compared to single arm treatment.