Phytotherapeutics Oridonin and Ponicidin show Additive Effects Combined with Irradiation in Pancreatic Cancer in Vitro.
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ABSTRACT: Background:Chemoradiation of locally advanced non-metastatic pancreatic cancer can lead to secondary operability by tumor mass reduction. Here, we analyzed radiomodulating effects of oridonin and ponicidin in pancreatic cancer in vitro. Both agents are ent-kaurane diterpenoids, extracted from Isodon rubescens, a plant that is well known in Traditional Chinese Medicine. Cytotoxic effects have recently been shown in different tumor entities for both agents. Materials and methods:Pancreatic cancer cell lines AsPC-1, BxPC-3, Panc-1 and MIA PaCa-2 were pretreated with oridonin or ponicidin and irradiated with 2 Gy to 6 Gy. Long-term survival was determined by clonogenic assay. Cell cycle effects and intensity of ?H2AX as indicator for DNA double-strand breaks were investigated by flow cytometry. Western blotting was used to study the DNA double-strand break repair proteins Ku70, Ku80 and XRCC4. Results:Oridonin and ponicidin lead to a dose-dependent reduction of clonogenic survival and an increase in ?H2AX. Combined with irradiation we observed additive effects and a prolonged G2/M-arrest. No relevant changes in the levels of the DNA double-strand break repair proteins were detected. Conclusions:Pretreatment with oridonin or ponicidin followed by irradiation lead to an additional reduction in survival of pancreatic cancer cells in vitro, presumably explained by an induced prolonged G2/M-arrest. Both agents seem to induce DNA double-strand breaks but do not interact with the non-homologous end joining (NHEJ) pathway.
SUBMITTER: Liermann J
PROVIDER: S-EPMC5765317 | biostudies-literature | 2017 Dec
REPOSITORIES: biostudies-literature
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