Abstract 4385: The green tea polyphenol EGCG induces mesenchymal to epithelial transition (MET) and tumor regression in triple negative breast cancer (TNBC) cells and mouse xenograft model: involvement of CCN5

Background: Epithelial to Mesenchymal transition (EMT) is an important and coordinated series of events associated with tumor metastasis and invasion. Recent studies had shown the importance of CCN5 (also known as WISP-2,Wnt-1-induced signaling protein-2) in the regulation of various carcinomas including the breast cancer. Recent studies had showed that ectopic expression of CCN5 can reverse Epithelial-Mesenchymal transition (EMT) and inhibit cancer metastasis. Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, has been extensively studied as a bioactive dietary component against various types of carcinomas through multiple mechanisms such as anti-oxidation, induction of apoptosis, inhibition of angiogenesis and metastasis. However, the mechanism of action of EGCG in breast carcinoma is uncertain.

Objective: The objective of the present study is to determine whether CCN5 plays any significant role in EGCG-mediated cytotoxicity in triple negative breast cancer cells.

Results: Exposure of triple negative human breast cancer (TNBC) cells, MDA-MB-231 and HCC70 to EGCG resulted in a dose-dependent inhibition of proliferation after 72h and the IC50 was observed around 75μM for MDA-MB-231 cells and 50μM for HCC70 respectively. We found EGCG-treatment effectively induces MET and inhibits the in vitro migration parallel with the induction of CCN5 expression in TNBC cells in a dose-dependent fashion. Furthermore, consistent with in vitro findings, tumor progression was drastically inhibited in EGCG-treated MDA-MB-231-tumor xenograft in nude mouse model.

Conclusion: EGCG imparts its anti-cancer activity in both TNBC cells as well as MB-231-tumor xenografts via induction of CCN5.

Citation Format: Amlan Das, Snigdha Banerjee, Archana De, Inamul Haque, Gargi Maity, Matt McEwen, Sushanta K. Banerjee. The green tea polyphenol EGCG induces mesenchymal to epithelial transition (MET) and tumor regression in triple negative breast cancer (TNBC) cells and mouse xenograft model: involvement of CCN5. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4385. doi:10.1158/1538-7445.AM2013-4385

Sci-Fri PM: Delivery - 04: Quantitative air communication testing of ion chambers for megavoltage dosimetry

The valid application of the standard correction for air density (P_TP in the TG-51 protocol) requires that for a vented ion chamber (basically all reference-class ion chambers) the air cavity does indeed communicate directly with the external environment. However, this assumption is not tested by users, and not universally verified by calibration laboratories. A system has therefore been developed at the National Research Council to test air communication of cylindrical and parallel-plate ion chambers. The systems is based on measurements in a vacuum vessel with a Sr-90 check source; the procedure is simple and quick and can measure ionization currents over the pressure range 0 kPa (atmospheric) to -20kPa (0.8 atm) with an uncertainty better than 0.2%. Investigation of a wide range of chamber types shows that for a coarse check on chamber performance (i.e., that the chamber is vented to atmosphere) measurement at a single polarity is sufficient (total test time less than 15 minutes) but for accurate characterization of the chamber performance, data at both polarities must be acquired. The accuracy of the system means that it can potentially be used to investigate: i) the validity of the pressure correction, and ii) the source of the polarity correction in cylindrical and parallel-plate chambers. The air communication test will be implemented as part of the standard calibration services provided by NRC for external beam radiotherapy.