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Phytotherapeutics oridonin and ponicidin show additive effects combined with irradiation in pancreatic cancer in vitro Cover

Phytotherapeutics oridonin and ponicidin show additive effects combined with irradiation in pancreatic cancer in vitro

Open Access
|Nov 2017

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 γH2AX 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 γH2AX. 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.

DOI: https://doi.org/10.1515/raon-2017-0048 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099
Language: English
Page range: 407 - 414
Submitted on: Jun 28, 2017
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Accepted on: Oct 13, 2017
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Published on: Nov 29, 2017
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2017 Jakob Liermann, Patrick Naumann, Franco Fortunato, Thomas E. Schmid, Klaus-Josef Weber, Jürgen Debus, Stephanie E. Combs, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.