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. 2016 Jun 3;11(6):e0156833. doi: 10.1371/journal.pone.0156833

Fig 3. PIN1 inhibitor Juglone suppresses tumor cell growth and induces caspase-3 activity.

Fig 3

(A) HK-1 (left panel) and C666-1 (right panel) were treated with the PIN1 inhibitor Juglone for 24 hours to determine the drug dose sensitivity. The IC50 values of the C666-1 and HK1 cells were 6 μM and 10 μM, respectively. (B) The expression of cyclin D1 was suppressed by Juglone in a dose-dependent manner, but no significant changes in β-catenin expression were detected. The expression of cyclin D1 and β-catenin in the Juglone-treated C-666 xenograft model was examined by Western blot. Reduced expression of cyclin D1 was observed in the tumor that had received Juglone treatment. PIN1 inhibition resulted in suppression of cyclin D1 both in vitro and in vivo, and there was a modest reduction in the β-catenin level in the in vivo model. (C) The C666-1 cells exhibited significantly higher caspase-3 activity after Juglone treatment, compared with their untreated or DMSO-treated counterparts. This indicates that PIN1 inhibition can activate the caspase apoptotic pathway in NPC cells. Statistical significance was determined by Student t-test, P-value of less than 0.05 was considered significant (*P < 0.05, **P < 0.01).