P-018 - Desacetyl isovaltratum, an extract from Valeriana, induces G2/M phase arrest and apoptosis in gastric cancer cell lines

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Basic Science
Gastric Cancer
Presenter B. Zhang
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors B. Zhang, D. Zhang, N. Lin
  • Hangzhou First People's Hospital, Hangzhou/CN

Abstract

Introduction

Desacetyl isovaltratum (DI) was a novel component isolated from the roots of Valeriana in our previous work. DI exhibited obvious anticancer activity against a variety of cancer cell lines in vitro, while presenting the strongest anti-proliferation effect against gastric cancer cells.

Methods

GeneChip Human Genome U133 Plus 2.0 Array was used to determine the mRNA expression before and after DI treatment. MTT assay and colony formation assay was used to determine the in vitro cytotoxicity of DI in several cancer cell lines. Flow cytometry was utilized to analyze the cell cycle distribution and apoptotic cells. Western blot was used to detect the protein expression level. Tubulin polymerization assay was used to determine the effect of DI on tubulin polymerization.

Results

Using microarray we found that DI dramatically affected the cell cycle determinant proteins in two gastric cancer cell lines AGS and HGC-27. Flow cytometric analysis showed that DI caused G2/M phase arrest at short treatment time, while prolonging the DI treatment led to the induction of apoptosis in both AGS and HGC-27 cell lines. MTT assay suggested that DI could effectively inhibit the proliferation of AGS and HGC-27 cells, which was due to the induction of apoptosis as indicated by DAPI staining. Western blot demonstrated that DI down-regulated the expression of cdc2 and cdc25c, meanwhile up-regulated the expression of p-Chk1 and active caspase3. However, the protein expression of cyclinB was found barely unchanged. Further results showed that DI effectively expedited the tubulin polymerization as compared with untreated cells, suggesting that DI stalled cell cycle in M phase.

Conclusion

In summary, DI was a novel compound isolated from Valeriana. The antitumor effect of DI could attribute to the its G2/M phase arrest activity through Chk1-cdc25c-cdc2 pathways, and also interfering with normal tubulin polymerization process. Further exposure to DI could induce caspase-dependent apoptosis. Therefore, as a newly extracted compound, DI exhibited its strong antitumor activity against gastric carcinoma.