PI3K as a Potential Therapeutic Target in Thymic Epithelial Tumors Anna Teresa Alberobello, PhD, Yisong Wang, PhD, Frans Joseph Beerkens, BS, Fabio Conforti, MD, Justine N. McCutcheon, BS, Guanhua Rao, PhD, Mark Raffeld, MD, Jing Liu, MD, Raneen Rahhal, BS, Yu-Wen Zhang, MD, PhD, Giuseppe Giaccone, MD, PhD Journal of Thoracic Oncology Volume 11, Issue 8, Pages 1345-1356 (August 2016) DOI: 10.1016/j.jtho.2016.04.013 Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Figure 1 Morphological features and characterization of MP57 primary cells. (A) Photographs of MP57 morphological features at passages 16 and 30 taken under a light-inverted microscope (magnification ×40). (B) Immunofluorescence staining of thymic epithelial markers in MP57. The staining of cytokeratin clone AE1/AE3, EpCAM, E-cadherin, c-Kit, and p63 are indicated by fluorescein isothiocyanate (FITC). 4,6-Diamino-2-phenylindole (DAPI) was used for staining of nuclei. (C) Cell surface marker analysis of MP57 by flow cytometry. Cytokeratin clone AE1/AE3, EpCAM, p63, c-Kit, and E-cadherin and human fibroblast antibody were analyzed. Black histogram represents control isotypes. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Figure 2 Proliferative and tumorigenic activities of MP57 cells. Cell proliferation was measured by CellTiter Glo Viability assay (A) and the trypan blue dye exclusion method (B). For comparison, T1889 and IU-TAB1 cells were also examined. (C) Tumorigenicity of MP57 cells in immunocompromised athymic nude mice (n = 10). The curve represents the growth of subcutaneous tumors within the 5-week window. (D) MP57 xenograft tumors at the experimental end point (day35 after inoculation). (E) Histological comparison of MP57 xenograft tumor and the primary tumor obtained from patient autopsy. Morphological pattern of tumor cells was examined by hematoxylin and eosin (H&E) staining. The expression of cytokeratin 7 and p63 was determined by immunohistochemical staining. Abbreviation: RLU, relative luminescence units. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Figure 3 Identification of mutations in the genes encoding subunits of PI3K in thymic epithelial tumor samples. Sanger sequencing confirmation of mutations identified by MiSeq in (A) phosphoinositide-3-kinase regulatory subunit 2 gene (PIK3R2) in MP57 cells and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA) in IU-TAB1 cells. (B) Sanger sequencing of mutations identified in PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma gene (PIK3CG), and phosphoinositide-3-kinase regulatory subunit 4 gene (PIK3R4) in three thymic epithelial tumor primary tumor samples, respectively. Arrows indicate the mutated nucleotides. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Figure 4 PI3K inhibition suppressed protein kinase B (AKT) activation and reduced viability of TET cells. (A) Western blot analysis of AKT phosphorylation in MP57, IU-TAB1, and T1889 cells treated with the indicated concentration of GDC-0941 for 6 hours. As controls, total AKT and β-actin were also probed. (B) The viability of the indicated cells treated with increasing concentrations of GDC-0941 (ranging from 70 nM to 20 μM) for 72 hours, determined by CellTiter Glo Viability assay. The concentrations that inhibit 50% were calculated using the GraphPad Prism program (GraphPad Software, La Jolla, CA). The assay was performed in triplicate, and the error bars represent standard deviations. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Figure 5 Effects of GDC-0941 on cell cycle, apoptosis, and motility of PI3K-mutated thymic epithelial cells. (A) Cell cycle analysis of MP57 and IU-TAB1 cells treated with the indicated concentrations of GDC-0941 for 72 hours, determined by flow cytometry of propidium iodide (PI) staining. DMSO treatment was used as the control. (B) Analysis of apoptosis by flow cytometry using annexin V and propidium iodide staining of the cells treated with the indicated concentrations of GDC-0941 for 72 hours. (C) Migration assay of MP57 cells treated with and without GDC-0941. Migrating cells were visualized by crystal violet staining (left), and the quantification was shown in the graph bars (right). Error bar represents standard deviation. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions
Supplementary Fig. 1 MP57 cells do not express vimentin and N-cadherin. Immunofluorescence staining was used to detect vimentin and N-cadherin (FITC). DAPI was used to stain the nucleus of the cells. Journal of Thoracic Oncology 2016 11, 1345-1356DOI: (10.1016/j.jtho.2016.04.013) Copyright © 2016 International Association for the Study of Lung Cancer Terms and Conditions