title: Radiosensitivity of human ovarian carcinoma and melanoma cells to γ-rays and protons.
abstract: BACKGROUND
  Proton radiation offers physical advantages over conventional radiation. Radiosensitivity of human 59M ovarian cancer and HTB140 melanoma cells was investigated after exposure to γ-rays and protons.
  
  
  METHODS
  Irradiations were performed in the middle of a 62 MeV therapeutic proton spread out Bragg peak with doses ranging from 2 to 16 Gy. The mean energy of protons was 34.88 ±2.15 MeV, corresponding to the linear energy transfer of 4.7 ±0.2 keV/µm. Irradiations with γ-rays were performed using the same doses. Viability, proliferation and survival were assessed 7 days after both types of irradiation while analyses of cell cycle and apoptosis were performed 48 h after irradiation.
  
  
  RESULTS
  Results showed that γ-rays and protons reduced the number of viable cells for both cell lines, with stronger inactivation achieved after irradiation with protons. Surviving fractions for 59M were 0.91 ±0.01 for γ-rays and 0.81 ±0.01 for protons, while those for HTB140 cells were 0.93 ±0.01 for γ-rays and 0.86 ±0.01 for protons. Relative biological effectiveness of protons, being 2.47 ±0.22 for 59M and 2.08 ±0.36 for HTB140, indicated that protons provoked better cell elimination than γ-rays. After proton irradiation proliferation capacity of the two cell lines was slightly higher as compared to γ-rays. Proliferation was higher for 59M than for HTB140 cells after both types of irradiation. Induction of apoptosis and G2 arrest detected after proton irradiation were more prominent in 59M cells.
  
  
  CONCLUSIONS
  The obtained results suggest that protons exert better antitumour effects on ovarian carcinoma and melanoma cells than γ-rays. The dissimilar response of these cells to radiation is related to their different features.
authors.affiliation: Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: Otilija
authors.initials: O
authors.lastname: Keta
authors.affiliation: Medical Faculty, University of Kragujevac, Kragujevac, Serbia.
authors.forename: Danijela
authors.initials: D
authors.lastname: Todorović
authors.affiliation: Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: Nataša
authors.initials: N
authors.lastname: Popović
authors.affiliation: Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: Lela
authors.initials: L
authors.lastname: Korićanac
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Cuttone
authors.affiliation: Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Petrović
authors.affiliation: Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Ristić-Fira
keywords: apoptosis; cell cycle; melanoma; ovarian carcinoma; protons; γ-rays
references.citation: Clin Oncol (R Coll Radiol). 1997;9(2):70-8
references.pmid: 9135890
references.citation: Br J Cancer. 2003 Aug 4;89(3):593-601
references.pmid: 12888835
references.citation: AJR Am J Roentgenol. 1976 Dec;127(6):1027-32
references.pmid: 1069484
references.citation: Arch Med Sci. 2012 Nov 9;8(5):848-53
references.pmid: 23185194
references.citation: Mol Cell Biol. 2009 May;29(10):2828-40
references.pmid: 19273588
references.citation: J Radiat Res. 2007 Sep;48(5):407-15
references.pmid: 17660698
references.citation: Cancer Chemother Pharmacol. 2003 Mar;51(3):221-6
references.pmid: 12655440
references.citation: J Radiat Res. 2009 Jan;50(1):27-36
references.pmid: 19218779
references.citation: Eur J Cancer. 1994;30A(9):1370-6
references.pmid: 7999427
references.citation: Apoptosis. 2006 Jan;11(1):57-66
references.pmid: 16374542
references.citation: Int J Radiat Biol. 2006 Apr;82(4):251-65
references.pmid: 16690593
references.citation: Radiat Oncol Investig. 1999;7(2):77-85
references.pmid: 10333248
references.citation: Phys Med. 2008 Dec;24(4):187-95
references.pmid: 18514560
references.citation: Mol Ther. 2000 Jun;1(6):545-54
references.pmid: 10933979
references.citation: Anticancer Drugs. 1995 Feb;6(1):115-23
references.pmid: 7538827
references.citation: Eur J Cancer. 1991;27(7):897-900
references.pmid: 1834124
references.citation: Arch Med Sci. 2011 Feb;7(1):27-33
references.pmid: 22291729
references.citation: Radiat Res. 2000 Mar;153(3):279-88
references.pmid: 10669549
references.citation: Curr Opin Chem Biol. 1999 Feb;3(1):77-83
references.pmid: 10021401
references.citation: Oncogene. 2003 May 19;22(20):3138-51
references.pmid: 12789290
references.citation: Ann N Y Acad Sci. 2007 Jan;1095:165-74
references.pmid: 17404029
references.citation: DNA Repair (Amst). 2012 Jan 2;11(1):92-8
references.pmid: 22133811
references.citation: Int J Radiat Biol. 2010 Sep;86(9):742-51
references.pmid: 20597839