title: Modulation of Regorafenib effects on HCC cell lines by epidermal growth factor.
abstract: OBJECTIVE
  Blood platelet numbers are correlated to growth and aggressiveness of several tumor types, including hepatocellular carcinoma (HCC). We previously found that platelet lysates (hPLs) also stimulated growth and migration, and antagonized the growth-inhibitory and apoptotic effects of both Sorafenib and Regorafenib, two multikinase inhibitors, on three HCC cell lines. In this study, in vitro function of human epidermal growth factor (EGF) with and without Sorafenib or Regorafenib was investigated.
  
  
  METHODS
  An ELISA kit was used to evaluate the EGF concentrations in hPLs. In vitro function of EGF was assessed with proliferation MTT test. Apoptosis assay, scratch assays, and Transwell assays were performed for apoptosis, invasion, and migration, respectively. MAPK Activation Kit was used to explore MAPK phosphorylation.
  
  
  RESULTS
  EGF antagonized the growth inhibition of Regorafenib on three HCC cell lines. Regorafenib-mediated growth inhibition was blocked by 70 % when the cells were pre-treated with EGF. EGF also blocked Regorafenib-induced apoptosis, as well as Regorafenib-induced decreases in cell migration and invasion. The EGF effects were in turn antagonized by concomitant addition to the cultures of EGF receptor antagonist Erlotinib, showing that the EGF receptor was involved in the mechanisms of EGF-mediated blocking of Regorafenib effects. Erlotinib also partially blocked the effects of hPLs in antagonizing Regorafenib-mediated growth inhibition, showing that EGF was an important component of hPL actions.
  
  
  CONCLUSIONS
  All these results show that EGF antagonized Regorafenib-mediated growth and migration inhibition and apoptosis induction in HCC cells and reinforce the idea that microenvironment can influence cancer drug actions.
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Rosalba
authors.initials: R
authors.lastname: D'Alessandro
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Refolo
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Catia
authors.initials: C
authors.lastname: Lippolis
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Nicola
authors.initials: N
authors.lastname: Carella
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Caterina
authors.initials: C
authors.lastname: Messa
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Aldo
authors.initials: A
authors.lastname: Cavallini
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department Clinical Pathology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013 Castellana Grotte, BA, Italy.|Department of Gastroenterology and Hepatology, Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Brian Irving
authors.initials: BI
authors.lastname: Carr
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000378:metabolism*; D000069347:Erlotinib Hydrochloride; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009536:Niacinamide / Q000031:analogs & derivatives / Q000494:pharmacology; D010671:Phenylurea Compounds / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology; D000077157:Sorafenib
chemical_list: D000970:Antineoplastic Agents; D010671:Phenylurea Compounds; D011725:Pyridines; D011799:Quinazolines; C559147:regorafenib; D009536:Niacinamide; D004815:Epidermal Growth Factor; D000077157:Sorafenib; D000069347:Erlotinib Hydrochloride