In vitro and in vivo Study on Glioma Treatment Enhancement by Combining Temozolomide with Calycosin and Formononetin

Abstract

Ethnopharmacological relevance: Astragalina alpestris is a traditional Chinese herbal medicine with anti-inflammatory, anti-immune, anti-tumor and other pharmacological effects. Calycosin and formononetin (FMN) are two natural compounds isolated from astragalus. It has been shown that calycosin and FMN are active anti-tumor ingredient.

Aim of the study: The aim of this current work was to study the therapeutic enhancement of temozolomide (TMZ) on gliomavia combining with calycosin and FMN.

Materials and methods: The effect of co-administration via hematoxylin-eosin staining (HE staining) was determined by measuring cell proliferation toxicity with the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, Thiazolyl Blue Tetrazolium Bromide (MTT) assay and sequentially observing the cell morphology. To synchronously explore the effect of migration on C6, transwell assay and wound healing assay were performed. Apoptosis was measured by Annexin V/propidium iodide (PI) staining. Meanwhile, western blot was used to investigate proteins involved in the mechanisms for migration and apoptosis. Furthermore, HE staining and immunohistochemistry were also analyzed for curative effect in vivo.

Results: The efficacy of TMZ on glioma could be enhanced by combining with calycosin and FMN through inhibiting the proliferation and migration of glioma cells and promoting their apoptosis. Western blot assays indicated that expression of apoptotic proteins (Bcl-2 Associated XProtein (Bax), Cleaved Caspase-3, Cleaved Caspase-9) were up-regulated. Anti-apoptotic protein (B-cell lymphoma-2,Bcl-2) was down-regulated. The migratory proteins (Matrix metallopeptidase 2, 9, MMP-2, MMP-9) was downregulated. In vivo study, this kind of co-administration (calycosin, FMN, and TMZ) exhibited the marked therapeutic effect on glioma.

Conclusions: This study has identified that calycosin and FMN can increase the treatment effect of TMZ in vitro and in vivo. These attractive features substantially broadened the application range of TMZ as a glioma treatment medicine.

Keywords: Calycosin; Combination treatment; Formononetin; Glioma; Temozolomide.