Inhibition of the PI3K/AKT pathway potentiates cytotoxicity of EGFR kinase inhibitors in triple-negative breast cancer cells

Triple‐negative breast cancers (TNBCs) are known to be intrinsically resistant to inhibitors for epidermal growth factor receptor (EGFR). Until now, clinical trials for TNBCs using EGFR inhibitors (EGFRis) as single agents have yielded disappointing results. Here, we report that combinatorial treatment using EGFRis, such as gefitinib or erlotinib, with PI3K/AKT pathway inhibitors (PI3K/AKTis) demonstrated a synergistic, anti‐proliferative effect in cell lines of the basal‐like (BL) subtype, a subtype of TNBC. Western blot analysis revealed that the gefitinib/PI‐103 combination significantly reduced the level of both phospho‐AKT and phospho‐ERK in two susceptible BL subtype cell lines, SUM149PT and MDA‐MB‐468, whereas it had little or no effect on the level of phospho‐ERK in two non‐susceptible cell lines (HS578T and MDA‐MB‐231) of mesenchymal stem‐like (MSL) TNBC subtype. The gefitinib/PI‐103 combination also significantly induced caspase‐3/7‐mediated PARP cleavage and reduced two anti‐apoptotic proteins, XIAP and Bcl‐2 in the susceptible cell lines. In addition, the level of myeloid cell leukemia 1 (Mcl‐1) protein was markedly decreased by gefitinib/PI‐103 combination in the BL TNBC cells, but showed no significant change by this combination in MSL subtype cells. These results suggest that pharmacological inhibition of EGFR used in combination of PI3K/AKTis is a potential therapeutic approach to treat a subtype of TNBCs.

[1]  C. Kuperwasser,et al.  Fibroblast-secreted hepatocyte growth factor mediates epidermal growth factor receptor tyrosine kinase inhibitor resistance in triple-negative breast cancers through paracrine activation of Met , 2012, Breast Cancer Research.

[2]  Yuan Qi,et al.  Prognostic and therapeutic implications of distinct kinase expression patterns in different subtypes of breast cancer. , 2010, Cancer research.

[3]  Melissa L. Johnson,et al.  Emerging targeted therapies for breast cancer. , 2007, Hematology/oncology clinics of North America.

[4]  Gur Pines,et al.  The ERBB network: at last, cancer therapy meets systems biology , 2012, Nature Reviews Cancer.

[5]  S. Chandarlapaty,et al.  PI3K inhibition results in enhanced HER signaling and acquired ERK dependency in HER2-overexpressing breast cancer , 2011, Oncogene.

[6]  L. Carey,et al.  Triple-negative breast cancer: disease entity or title of convenience? , 2010, Nature Reviews Clinical Oncology.

[7]  Ting-Chao Chou,et al.  Theoretical Basis, Experimental Design, and Computerized Simulation of Synergism and Antagonism in Drug Combination Studies , 2006, Pharmacological Reviews.

[8]  W. Muller,et al.  Distinct biological roles for the akt family in mammary tumor progression. , 2010, Cancer research.

[9]  Paul Ellis,et al.  Dissecting the heterogeneity of triple-negative breast cancer. , 2012, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[10]  David E. Housman,et al.  mTORC1 promotes survival through translational control of Mcl-1 , 2008, Proceedings of the National Academy of Sciences.

[11]  H. Varmus,et al.  KRAS Mutations and Primary Resistance of Lung Adenocarcinomas to Gefitinib or Erlotinib , 2005, PLoS medicine.

[12]  D. Green,et al.  Glycogen synthase kinase-3 regulates mitochondrial outer membrane permeabilization and apoptosis by destabilization of MCL-1. , 2006, Molecular cell.

[13]  Y. Seong,et al.  BRCA1 negatively regulates IGF-1 expression through an estrogen-responsive element-like site , 2012, Cell Death and Disease.

[14]  W. Denny,et al.  Tyrosine kinase inhibitors. 8. An unusually steep structure-activity relationship for analogues of 4-(3-bromoanilino)-6,7-dimethoxyquinazoline (PD 153035), a potent inhibitor of the epidermal growth factor receptor. , 1996, Journal of medicinal chemistry.

[15]  X. Chen,et al.  Identification of human triple-negative breast cancer subtypes and preclinical models for selection of targeted therapies. , 2011, The Journal of clinical investigation.

[16]  Sarat Chandarlapaty,et al.  AKT inhibition relieves feedback suppression of receptor tyrosine kinase expression and activity. , 2011, Cancer cell.

[17]  Sharon Peplinski,et al.  X-Linked Inhibitor of Apoptosis Protein Inhibits Apoptosis in Inflammatory Breast Cancer Cells with Acquired Resistance to an ErbB1/2 Tyrosine Kinase Inhibitor , 2010, Molecular Cancer Therapeutics.

[18]  Robbie Loewith,et al.  A Pharmacological Map of the PI3-K Family Defines a Role for p110α in Insulin Signaling , 2006, Cell.

[19]  Carlos L. Arteaga,et al.  Feedback upregulation of HER3 (ErbB3) expression and activity attenuates antitumor effect of PI3K inhibitors , 2011, Proceedings of the National Academy of Sciences.

[20]  J. Hunt,et al.  Preclinical Antitumor Activity of BMS-599626, a pan-HER Kinase Inhibitor That Inhibits HER1/HER2 Homodimer and Heterodimer Signaling , 2006, Clinical Cancer Research.

[21]  F. Bazan,et al.  Deubiquitinase USP9X stabilizes MCL1 and promotes tumour cell survival , 2010, Nature.

[22]  A. Seidman,et al.  Emerging targeted therapies for breast cancer. , 2007, Hematology/oncology clinics of North America.

[23]  P. Majumder,et al.  MK-2206, an Allosteric Akt Inhibitor, Enhances Antitumor Efficacy by Standard Chemotherapeutic Agents or Molecular Targeted Drugs In vitro and In vivo , 2010, Molecular Cancer Therapeutics.

[24]  N. Normanno,et al.  Target-based therapies in breast cancer: current status and future perspectives. , 2009, Endocrine-related cancer.

[25]  O. Olopade,et al.  Epidermal Growth Factor Receptor in Triple-Negative and Basal-Like Breast Cancer: Promising Clinical Target or Only a Marker? , 2010, Cancer journal.

[26]  William Pao,et al.  Transcriptional and posttranslational up-regulation of HER3 (ErbB3) compensates for inhibition of the HER2 tyrosine kinase , 2011, Proceedings of the National Academy of Sciences.

[27]  S. Chia,et al.  What Is the Difference Between Triple-Negative and Basal Breast Cancers? , 2010, Cancer journal.

[28]  S. Pandey,et al.  Potential mechanism(s) involved in the regulation of glycogen synthesis by insulin , 1998, Molecular and Cellular Biochemistry.

[29]  T. Sørlie,et al.  Triple‐negative breast cancer: Present challenges and new perspectives , 2010, Molecular oncology.

[30]  S. Eccles.  The epidermal growth factor receptor/Erb-B/HER family in normal and malignant breast biology. , 2011, The International journal of developmental biology.

[31]  D. Green,et al.  The BCL-2 family reunion. , 2010, Molecular cell.

[32]  D. Spandidos,et al.  Gene alterations in the PI3K/PTEN/AKT pathway as a mechanism of drug-resistance (review). , 2011, International journal of oncology.

[33]  Antai Wang,et al.  Loss of BRCA1 leads to an increased sensitivity to Bisphenol A. , 2010, Toxicology letters.

[34]  P. Cohen,et al.  Inhibition of glycogen synthase kinase-3 by insulin mediated by protein kinase B , 1995, Nature.

[35]  L. Trusolino,et al.  The Met oncogene and basal-like breast cancer: another culprit to watch out for? , 2010, Breast Cancer Research.

[36]  P. Harari,et al.  Understanding resistance to EGFR inhibitors—impact on future treatment strategies , 2010, Nature Reviews Clinical Oncology.

[37]  M. Clynes,et al.  Epidermal growth factor receptor as a potential therapeutic target in triple-negative breast cancer. , 2009, Annals of oncology : official journal of the European Society for Medical Oncology.

[38]  M. Kris,et al.  'Targeting' the epidermal growth factor receptor tyrosine kinase with gefitinib (Iressa) in non-small cell lung cancer (NSCLC). , 2004, Seminars in cancer biology.

[39]  M. Meyerson,et al.  BIBW2992, an irreversible EGFR/HER2 inhibitor highly effective in preclinical lung cancer models , 2008, Oncogene.

[40]  Antai Wang,et al.  Inhibition of constitutively activated phosphoinositide 3‐kinase/AKT pathway enhances antitumor activity of chemotherapeutic agents in breast cancer susceptibility gene 1‐defective breast cancer cells , 2013, Molecular carcinogenesis.