Regorafenib: Antitumor Activity upon Mono and Combination Therapy in Preclinical Pediatric Malignancy Models

PLoS One. 2015 Nov 23;10(11):e0142612. doi: 10.1371/journal.pone.0142612. eCollection 2015.

Abstract

The multikinase inhibitor regorafenib (BAY 73-4506) exerts both anti-angiogenic and anti-tumorigenic activity in adult solid malignancies mainly advanced colorectal cancer and gastrointestinal stromal tumors. We intended to explore preclinically the potential of regorafenib against solid pediatric malignancies alone and in combination with anticancer agents to guide the pediatric development plan. In vitro effects on cell proliferation were screened against 33 solid tumor cell lines of the Innovative Therapies for Children with Cancer (ITCC) panel covering five pediatric solid malignancies. Regorafenib inhibited cell proliferation with a mean half maximal growth inhibition of 12.5 μmol/L (range 0.7 μmol/L to 28 μmol/L). In vivo, regorafenib was evaluated alone at 10 or 30 mg/kg/d or in combination with radiation, irinotecan or the mitogen-activated protein kinase kinase (MEK) inhibitor refametinib against various tumor types, including patient-derived brain tumor models with an amplified platelet-derived growth factor receptor A (PDGFRA) gene. Regorafenib alone significantly inhibited tumor growth in all xenografts derived from nervous system and connective tissue tumors. Enhanced effects were observed when regorafenib was combined with irradiation and irinotecan against PDGFRA amplified IGRG93 glioma and IGRM57 medulloblastoma respectively, resulting in 100% tumor regressions. Antitumor activity was associated with decreased tumor vascularization, inhibition of PDGFR signaling, and induction of apoptotic cell death. Our work demonstrates that regorafenib exhibits significant antitumor activity in a wide spectrum of preclinical pediatric models through inhibition of angiogenesis and induction of apoptosis. Furthermore, radio- and chemosensitizing effects were observed with DNA damaging agents in PDGFR amplified tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antineoplastic Agents / therapeutic use*
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Apoptosis / drug effects
  • Camptothecin / analogs & derivatives
  • Camptothecin / therapeutic use
  • Cell Line, Tumor
  • Cell Proliferation
  • Child
  • Drug Screening Assays, Antitumor
  • Female
  • Humans
  • In Situ Hybridization, Fluorescence
  • Irinotecan
  • MAP Kinase Signaling System
  • Male
  • Mice
  • Neoplasm Transplantation
  • Neoplasms / drug therapy*
  • Neoplasms / metabolism
  • Neovascularization, Pathologic / drug therapy
  • Phenylurea Compounds / therapeutic use*
  • Pyridines / therapeutic use*

Substances

  • Antineoplastic Agents
  • Phenylurea Compounds
  • Pyridines
  • regorafenib
  • Irinotecan
  • Camptothecin

Grants and funding

This preclinical evaluation was supported by: Bayer Pharma Aktiengesellschaft, (BG), 'Enfants et Santé' and the 'Société Française des Cancers de l'Enfant'. Bayer Pharma Aktiengesellschaft provided support in the form of salaries for authors [DZ] and had a role in study design, data collection and analysis, decision to publish, and preparation of the manuscript. Tribvn provided support in the form of salaries for authors [AV] and had a collaborative role in data analysis and preparation of the manuscript without financial support. The specific roles of these authors are articulated in the ‘author contributions’ section.