Neuroprotective Effect of β-Lapachone in MPTP-Induced Parkinson's Disease Mouse Model: Involvement of Astroglial p-AMPK/Nrf2/HO-1 Signaling Pathways

Parkinson's disease is a neurodegenerative disease characterized by the progressive loss of dopaminergic neurons within the substantia nigra pars compacta. In the present study, we investigated whether β-Lapachone (β-LAP), a natural naphthoquinone compound isolated from the lapacho tree (Tabebuia avellanedae), elicits neuroprotective effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mouse model. β-LAP reduced the tyrosine hydroxylase (TH)-immuno-reactive fiber loss induced by MPTP in the dorsolateral striatum, and alleviated motor dysfunction as determined by the rotarod test. In addition, β-LAP protected against MPTP-induced loss of TH positive neurons, and upregulated B-cell lymphoma 2 protein (Bcl-2) expression in the substantia nigra. Based on previous reports on the neuroprotective role of nuclear factor-E2-related factor-2 (Nrf2) in neurodegenerative diseases, we investigated whether β-LAP induces upregulation of the Nrf2-hemeoxygenae-1 (HO-1) signaling pathway molecules in MPTP-injected mouse brains. Western blot and immunohistochemical analyses indicated that β-LAP increased HO-1 expression in glial fibrillary acidic protein-positive astrocytes. Moreover, β-LAP increased the nuclear translocation and DNA binding activity of Nrf2, and the phosphorylation of upstream adenosine monophosphate-activated protein kinase (AMPK). β-LAP also increased the localization of p-AMPK and Nrf2 in astrocytes. Collectively, our data suggest that β-LAP exerts neuroprotective effect in MPTP-injected mice by upregulating the p-AMPK/Nrf2/HO-1 signaling pathways in astrocytes.

Combination of β-lapachone and BEZ235 inhibits proliferation and migration of breast cancer cells / 肿瘤

Objective: To investigate the effects of β-lapachone combined with BEZ235 on the proliferation and migration of breast cancer cells, and to explore its possible mechanism. Methods: The effects of β-lapachone and BEZ235 alone or combination on the proliferation of breast cancer MCF-7 and MDA-MB-468 cells were detected by MTT assay, and the combination index (CI) was calculated. The expression level of proliferation-related protein Ki67 in MCF-7 and MDA-MB-468 cells was detected by Western blotting. The colony formation ability of MCF-7 and MDA-MB-468 cells was detected by plate cloning assay. The lateral migration, vertical migration and invasion abilities of MCF-7 and MDA-MB-468 cells were detected by scratch healing experiment and Transwell chamber assay, respectively. The expression levels of epithelialmesenchymal transition (EMT)-related proteins in MCF-7 and MDA-MB-468 cells were detected by Western blotting. The angiogenesis assay was used to detect the angiogenic ability of human umbilical vein endothelial cells (HUVECs) cultured with the supernatants of MCF-7 and MDAMB- 468 cells treated with β-lapachone, BEZ235 and their combination. The effects of β-lapachone and BEZ235 alone or combination on the expression of vascular endothelial growth factor (VEGF) in breast cancer MCF-7 and MDA-MB-468 cells were detected by Western blotting. Results: The proliferation abilities of breast cancer MCF-7 and MDA-MB-468 cells in β-lapachone, BEZ235 alone or combination treatment groups were lower than those in the control group (without any treatment) (all P < 0.05). The two drugs had synergistic effect with CI < 1. The expression level of Ki67 protein in MCF-7 and MDA-MB-468 cells in β-lapachone combined with BEZ235 group was lower than that in the control and single drug groups (all P < 0.05). The number of colony formation of MCF-7 and MDA-MB-468 cells in β-lapachone combined with BEZ235 group was less than that in the control and single drug groups (all P < 0.05). The abilities of lateral migration, vertical migration and invasion of MCF-7 and MDA-MB-468 cells in β-lapachone combined with BEZ235 group were lower than those in the control and single drug groups (all P < 0.05). The expression level of EMTrelated protein E-cadherin in MCF-7 and MDA-MB-468 cells treated with β-lapachone and BEZ235 was higher than that in the control and single drug groups (all P < 0.05), whereas the expression levels of Vimentin and Twist were opposite (all P < 0.05). The vascularization number of HUVECs, which cultured in the supernatants of MCF-7 and MDA-MB-468 cells treated with β-lapachone and BEZ235, was significantly lower than that in the control and single drug groups (all P < 0.01). The expression level of VEGF in MCF-7 and MDA-MB-468 cells treated with β-lapachone and BEZ235 was lower than that in the control and single drug groups (all P < 0.05). Conclusion: Combination of β-lapachone and BEZ235 can synergistically inhibit the proliferation of breast cancer cells in vitro, and suppress cell invasion and metastasis through angiogenesis and EMT pathway.