Inhibition of the colony-stimulating-factor-1 receptor affects the resistance of lung cancer cells to cisplatin.

// Harvey I. Pass 1 , Carmencita Lavilla 2 , Claudia Canino 1, 5 , Chandra Goparaju 1 , Jordan Preiss 1 , Samrah Noreen 2 , Giovanni Blandino 3, 4 , Mario Cioce 1, 3 1 Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Langone Medical Center, New York University, New York, USA 2 New York University Langone Medical Center, New York University, New York, USA 3 Translational Oncogenomics Unit, Italian National Cancer Institute 'Regina Elena', Rome, Italy 4 Department of Oncology, Juravinski Cancer Center-McMaster University, Hamilton, Ontario, Canada 5 University Campus Biomedico, Rome, Italy Correspondence to: Mario Cioce, email: mario.cioce@ifo.gov.it Keywords: lung cancer, chemoresistance, CSF-1, CSF-1R, ALDH Received: May 10, 2016      Accepted: June 30, 2016      Published: July 28, 2016 ABSTRACT In the present work we show that multiple lung cancer cell lines contain cisplatin resistant cell subpopulations expressing the Colony-Stimulating-Factor-Receptor-1 (CSF-1R) and surviving chemotherapy-induced stress. By exploiting siRNA-mediated knock down in vitro and the use of an investigational CSF-1R TKI (JNJ-40346527) in vitro and in vivo , we show that expression and function of the receptor are required for the clonogenicity and chemoresistance of the cell lines. Thus, inhibition of the kinase activity of the receptor reduced the levels of EMT-associated genes, stem cell markers and chemoresistance genes. Additionally, the number of high aldehyde dehydrogenase (ALDH) expressing cells was reduced, consequent to the lack of cisplatin-induced increase of ALDH isoforms. This affected the collective chemoresistance of the treated cultures. Treatment of tumor bearing mice with JNJ-40346527, at pharmacologically relevant doses, produced strong chemo-sensitizing effects in vivo . These anticancer effects correlated with a reduced number of CSF-1R pos cells, in tumors excised from the treated mice. Depletion of the CD45 pos cells within the treated tumors did not, apparently, play a major role in mediating the therapeutic response to the TKI. Thus, lung cancer cells express a functional CSF-1 and CSF-1R duo which mediates pro-tumorigenic effects in vivo and in vitro and can be targeted in a therapeutically relevant way. These observations complement the already known role for the CSF-1R at mediating the pro-tumorigenic properties of tumor-infiltrating immune components.