KRAS-mutation status dependent effect of zoledronic acid in human non-small cell cancer preclinical models.

// Istvan Kenessey 1, 2 , Krisztina Koi 1 , Orsolya Horvath 3 , Mihaly Cserepes 3, 4 , David Molnar 1 , Vera Izsak 1 , Judit Dobos 5 , Balazs Hegedűs 6 , Jozsef Tovari 3, * , Jozsef Timar 1, 6, * 1 2 nd Department of Pathology, Semmelweis University, Budapest, Hungary 2 National Cancer Registry, National Institute of Oncology, Budapest, Hungary 3 Department of Experimental Pharmacology, National Institute of Oncology, Budapest, Hungary 4 Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary 5 Vichem Chemie Ltd., Budapest, Hungary 6 Hungarian Academy of Sciences-Semmelweis University Molecular Oncology Research Group, Budapest, Hungary * These authors have contributed equally to this work Correspondence to: Istvan Kenessey, email: steveken12@yahoo.com Keywords: zoledronic acid, ras inhibitor, human non-small cell lung cancer, xenograft model Received: March 17, 2016      Accepted: September 27, 2016      Published: October 21, 2016 ABSTRACT Background: In non-small cell lung cancer (NSCLC) KRAS-mutant status is a negative prognostic and predictive factor. Nitrogen-containing bisphosphonates inhibit prenylation of small G-proteins (e.g. Ras, Rac, Rho) and thus may affect proliferation and migration. In our preclinical work, we investigated the effect of an aminobisphosphonate compound (zoledronic acid) on mutant and wild type KRAS-expressing human NSCLC cell lines. Results: We confirmed that zoledronic acid was unable to inhibit the prenylation of mutant K-Ras unlike in the case of wild type K-Ras. In case of in vitro proliferation, the KRAS-mutant human NSCLC cell lines showed resistance to zoledronic acid wild-type KRAS-cells proved to be sensitive. Combinatory application of zoledronic acid enhanced the cytostatic effect of cisplatin. Zoledronic acid did not induce significant apoptosis. In xenograft model, zoledronic acid significantly reduced the weight of wild type KRAS-EGFR-expressing xenograft tumor by decreasing the proliferative capacity. Futhermore, zoledronic acid induced VEGF expression and improved in vivo tumor vascularization. Materials and methods: Membrane association of K-Ras was examined by Western-blot. In vitro cell viability, apoptotic cell death and migration were measured in NSCLC lines with different molecular background. The in vivo effect of zoledronic acid was investigated in a SCID mouse subcutaneous xenograft model. Conclusions: The in vitro and in vivo inhibitory effect of zoledronic acid was based on the blockade of cell cycle in wild type KRAS-expressing human NSCLC cells. The zoledronic acid induced vascularization supported in vivo cytostatic effect. Our preclinical investigation suggests that patients with wild type KRAS-expressing NSCLC could potentially benefit from aminobisphosphonate therapy.