In vitro evaluation of combination of EGCG and Erlotinib with classical chemotherapeutics on JAR cells

Abstract

Gestational Trophoblastic Neoplasia (GTN) is a term used for a group of malignant gynecological tumors including choriocarcinoma. Low-risk neoplasias can be cured using single agents Methotrexate (MTX) and actinomycin-D (ACD), but in certain cases, decreased responsiveness and serious side effects occur. Therefore, researchers have been attempting to find new treatment modalities. One of the most popular way for increasing cancer patient survival rates is supporting treatment with adjuvant molecules or chemosensitizers. For this purpose, we investigated epigallocatechin-3-gallate (EGCG), a green tea cathecin, and Erlotinib, an EGFR tyrosine kinase inhibitor, as single agents and combined with MTX or ACD. In accordance with this, JAR (human placenta choriocarcinoma) cell line was used as an in vitro model and MTT, LDH, caspase-3 activation, RT-PCR, and Western Blot analyses were performed to investigate the effects of the test materials. Our studies demonstrate that combination of Erlotinib and EGCG with MTX and ACD decreases JAR cell proliferation and metastatic HER2 protein synthesis and increases caspase-3 activation compared to ACD or MTX alone. In addition, significant increase was observed in the apoptotic Bax gene, but no notable protein synthesis occurred in the Western Blot analysis, which suggests that combination of Erlotinib and EGCG with classical chemotherapeutics ACD or MTX may lead the JAR cells to apoptosis, but not by a mitochondrial pathway. All the results indicate that the synergetic effect of Erlotinib and EGCG with classical chemotherapeutics may help to increase patient survival rates of choriocarcinoma, but the detailed mechanism needs further investigation.