title: Gefitinib enhances the effects of combined radiotherapy and 5-fluorouracil in a colorectal cancer cell line.
abstract: OBJECTIVE
  In a phase I/II trial, patients with locally advanced rectal cancer received preoperative radiotherapy (RT) and concurrent with 5-fluorouracil (5-FU) and gefitinib. Results were promising. To elucidate the molecular and biological effects, we replicated the schedule in the LoVo human colorectal adenocarcinoma cell line.
  
  
  METHODS
  RT (2 Gy daily for 3 days), 5-FU (0.3, 0.6, 1.25, 2.5, 5, 10 μM) and gefitinib (0.2, 0.4, 0.8 μM) were administered alone, in double combinations and all together. We assessed viable cells, cell cycle, cyclin, p53 and p21 expression, signalling pathways by means of phosphorylated epidermal growth factor receptor (p-EGFR), p-AKT and p-ERK 1-2 and clonogenic capacity.
  
  
  RESULTS
  RT and 5-FU were cytotoxic. Gefitinib was cytostatic. RT reduced clonogenic capacity more than 5-FU. 5-FU induced more cell death than RT, but surviving cells were proliferative (cyclins and p-EGFR increased). 5-FU + RT had a synergistic effect. Gefitinib, enhancing G1 accumulation, reduced proliferation of cells surviving 5-FU and 5-FU + RT. It slightly increased the cytotoxicity of RT and 5-FU.
  
  
  CONCLUSIONS
  As gefitinib limited the proliferation rate of cells surviving 5-FU and 5-FU + RT in the LoVo cell line, it may be a useful addition to chemotherapy and RT in rectal cancer patients.
authors.affiliation: Radiation Oncology Section, Department of Surgical, Radiological and Odontostomatological Sciences, University of Perugia, Ospedale Santa Maria della Misericordia, Sant'Andrea delle Fratte, 06156, Perugia, Italy, isabella.palumbo@unipg.it.
authors.forename: Isabella
authors.initials: I
authors.lastname: Palumbo
authors.forename: Simonetta
authors.initials: S
authors.lastname: Piattoni
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Valentini
authors.forename: Valeria
authors.initials: V
authors.lastname: Marini
authors.forename: Paola
authors.initials: P
authors.lastname: Contavalli
authors.forename: Monica
authors.initials: M
authors.lastname: Calzuola
authors.forename: Fabio Maria
authors.initials: FM
authors.lastname: Vecchio
authors.forename: Debora
authors.initials: D
authors.lastname: Cecchini
authors.forename: Franca
authors.initials: F
authors.lastname: Falzetti
authors.forename: Cynthia
authors.initials: C
authors.lastname: Aristei
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D059248:Chemoradiotherapy; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D005472:Fluorouracil / Q000627:therapeutic use*; D000077156:Gefitinib; D006801:Humans; D011799:Quinazolines / Q000627:therapeutic use*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D011799:Quinazolines; D000077156:Gefitinib; D005472:Fluorouracil
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