Anti-tumorigenic and anti-angiogenic effects of natural conifer Abies sibirica terpenoids in vivo and in vitro

Aim: The natural terpenoid compound was explored in vitro and in vivo to investigate the anti-HCC properties. Methods: For our study we used Abisilin (R)-a novel natural pharmacological terpenoid compound extracted and purified from coniferous Pinaceae trees. Anti-tumorigenic properties of different concentrations of Abisilin (R) were tested on murine hepatoma Hepa 1-6 cell lines. The analysis of proliferation and apoptosis was performed using immunofluorescence microscopy, FACS and qPCR. As an in vivo approach, we tested Abisilin (R) (400 mg/kg/day, 14 days, orally) in xenograft mouse models of liver cancer and investigated tumor growth, proliferation, apoptosis and angiogenesis by means of Western blotting, immunofluorescence microscopy and qPCR. Results: Application of Abisilin (R) for 24 h at a dosage ranging from 0.03 to 0.045 mg significantly reduced the number of viable Hepa 1-6 cells and induced apoptotic cell death with microscopic evidence of changes in cell morphology, and positive TUNEL, cleaved caspase 3 and Annexin V/Propidium Iodide (PI) stainings. Furthermore, treatment with Abisilin (R) strongly inhibited proliferation, impaired mitosis and prompted cell cycle arrest by down-regulation of the Cyclin D1, E1 and A2 expression levels. In Hepa 1-6 xenograft in vivo model, Abisilin (R) considerably decreased the xenograft tumor size and tumor volume. Consistently with in vitro Abisilin (R) administration elicited apoptosis and inhibit proliferation in the xenograft tumor. We also found that Abisilin (R) remarkably decrease microvessel density, diminished tumor angiogenesis and reduced expression of ICAM-1. Moreover, the expression of pAMPK, a cellular energy sensor, was up-regulated after Abisilin (R) application. Conclusions: Anti-proliferative, pro-apoptotic activity and anti-angiogenic potential of natural conifer terpenoids might turn these compounds into an attractive drug candidate for combination therapy against liver cancer. (C) 2017 Elsevier Masson SAS. All rights reserved.