82P - Synergistic antitumor activity of afatinib and nintedanib through PP2A reactivation in non-small-cell lung cancer cells

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Cytotoxic agents
Cancer biology
Thoracic malignancies
Basic Scientific Principles
Therapy
Biological therapy
Presenter Ting-Ting Chao
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors T. Chao1, C. Chen2, Z. Peng3, C. Wang2
  • 1Medical Research Center, Cardinal Tien Hospital, 23148 - Taipei/TW
  • 2Department Of Internal Medicine, Cardinal Tien Hospital, Taipei/TW
  • 3Department Of Pharmacy, Cardinal Tien Hospital, Taipei/TW

Abstract

Background

PP2A is a tumor suppressor which is a complex protein phosphatase in regulating biological processes. Previously, we found afatinib induces cell apoptosis by PP2A-mediated Akt pathway downregulation through the inhibition of CIP2A protein in EGFR wild type NSCLC. Afatinib, a pan-HER inhibitor, is a 2nd generation EGFR-TKI and approved for the treatment of patients with NSCLC who harbor EGFR mutations. Nintedanib can inhibit VEGFR, PDGFR and FGFR kinase activity which contribute to the cell proliferation and survival. So far, there are still no effective target therapies for EGFR wild-type NSCLC. Therefore, we aim to test the synergistic anti-tumor efficacy and a novel molecular mechanism of combination therapy of afatinib and nintedanib on NSCLC cells without EGFR mutation.

Methods

Human NSCLC cell lines, A549 H358 H441 and H727, were used as the in vitro cell models. Flow cytometry assay, western blot analysis or caspase activity ELISA assay were used to detect the anti-tumor effects. PP2A activity assay, siRNA and QPCR were performed to determine the mechanism of combination efficacy. Furthermore, in vivo efficacy of combination treatment against A549 xenografts tumors were also determined in nude mice.

Results

Combined treatment of afatinib and nintedanib induced significant cell apoptosis in NSCLC cells. The enhanced apoptosis efficiency in combination was associated with reactivation of PP2A. We observed increased PP2A activity resulting from PME1 degradation by afatinib/nintedanib-induced anti-tumor efficacy. Inhibition of PP2A or ectopic expression of PME1 abolished the anti-tumor effects of combination treatment of afatinib and nintedanib. In in vivo study, we showed that the anti-tumor efficacy of combination of afatinib and nintedanib was better than alone. This ability was due to the suppression of p-ERK by reactivation of PP2A through downregulation of PME-1.

Conclusions

Our results provide in vitro and in vivo experimental evidences about the therapeutic potential in combination therapies with afatinib and nintidanib for EGFR wild type NSCLC treatment. Our findings disclose the therapeutic mechanism and suggest the feasibility of developing PP2A enhancers as a novel anti-cancer strategy.

Clinical trial identification

Legal entity responsible for the study

Cardinal Tien Hospital

Funding

National Science Council and Cardinal Tien Hospital

Disclosure

All authors have declared no conflicts of interest.