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Radiation effects on S-phase duration, labelling index, potential doubling time and DNA distribution in head and neck cancer xenografts

Zätterstrom, Ulf K; Engellau, Jacob LU ; Johansson, Maria C LU ; Wennerberg, Johan LU and Kjellén, Elisabeth LU (1995) In Acta Oncologica 34(2). p.205-211
Abstract
The effect of irradiation on S-phase duration (Ts), labelling index (LI), potential doubling time (Tpot), and cell cycle phase distributions was determined by DNA flow cytometry in xenografted human squamous cell carcinoma of the head and neck (SCCHN). Tumours were treated with a single dose of 3 Gy, and excised at intervals over a 90-h period. Six hours before each excision the tumours were labelled in vivo with bromodeoxyuridine (BrdUrd). Although the growth rate of irradiated tumours was comparable with that of untreated controls, analysis of BrdUrd uptake revealed a transient reduction of LI and a prolongation of Ts in irradiated tumours. Maximum mean Tpot was 931 days in irradiated tumours as compared to 13 days in untreated controls.... (More)
The effect of irradiation on S-phase duration (Ts), labelling index (LI), potential doubling time (Tpot), and cell cycle phase distributions was determined by DNA flow cytometry in xenografted human squamous cell carcinoma of the head and neck (SCCHN). Tumours were treated with a single dose of 3 Gy, and excised at intervals over a 90-h period. Six hours before each excision the tumours were labelled in vivo with bromodeoxyuridine (BrdUrd). Although the growth rate of irradiated tumours was comparable with that of untreated controls, analysis of BrdUrd uptake revealed a transient reduction of LI and a prolongation of Ts in irradiated tumours. Maximum mean Tpot was 931 days in irradiated tumours as compared to 13 days in untreated controls. The variations in Ts, LI and Tpot all occurred within the first hours after irradiation; during the remainder of the observation time, the values of the variables did not differ from those of untreated controls. In irradiated tumours the distribution of cells according to DNA content changed significantly on three occasions during the observation period: 1) Parallel to the initial lowering of LI and prolongation of Ts there was a transient increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S and G2; 2) At 18 h, the most pronounced cell cycle phase redistribution occurred when the G0/G1 fraction decreased and the S and G2 phase fractions increased; 3) At 66 h (i.e., approximately one cell cycle later), the pattern was the same as that after 18 h. The findings suggest that the transient prolongation of DNA replication seen in SCCHN cells immediately after a single radiation dose is a symptom of DNA damage inflicted during late G1 or early S-phase, and that this disturbance in DNA synthesis is associated with the subsequent accumulation of cells in G2 phase. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Oncologica
volume
34
issue
2
pages
205 - 211
publisher
Taylor & Francis
external identifiers
  • pmid:7718258
  • scopus:0028968107
ISSN
1651-226X
DOI
10.3109/02841869509093957
language
English
LU publication?
yes
id
1187f98e-d6e9-4e76-87db-5eb5a80be71c (old id 1108950)
date added to LUP
2008-07-25 11:27:24
date last changed
2017-01-01 06:52:11
@article{1187f98e-d6e9-4e76-87db-5eb5a80be71c,
  abstract     = {The effect of irradiation on S-phase duration (Ts), labelling index (LI), potential doubling time (Tpot), and cell cycle phase distributions was determined by DNA flow cytometry in xenografted human squamous cell carcinoma of the head and neck (SCCHN). Tumours were treated with a single dose of 3 Gy, and excised at intervals over a 90-h period. Six hours before each excision the tumours were labelled in vivo with bromodeoxyuridine (BrdUrd). Although the growth rate of irradiated tumours was comparable with that of untreated controls, analysis of BrdUrd uptake revealed a transient reduction of LI and a prolongation of Ts in irradiated tumours. Maximum mean Tpot was 931 days in irradiated tumours as compared to 13 days in untreated controls. The variations in Ts, LI and Tpot all occurred within the first hours after irradiation; during the remainder of the observation time, the values of the variables did not differ from those of untreated controls. In irradiated tumours the distribution of cells according to DNA content changed significantly on three occasions during the observation period: 1) Parallel to the initial lowering of LI and prolongation of Ts there was a transient increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S and G2; 2) At 18 h, the most pronounced cell cycle phase redistribution occurred when the G0/G1 fraction decreased and the S and G2 phase fractions increased; 3) At 66 h (i.e., approximately one cell cycle later), the pattern was the same as that after 18 h. The findings suggest that the transient prolongation of DNA replication seen in SCCHN cells immediately after a single radiation dose is a symptom of DNA damage inflicted during late G1 or early S-phase, and that this disturbance in DNA synthesis is associated with the subsequent accumulation of cells in G2 phase.},
  author       = {Zätterstrom, Ulf K and Engellau, Jacob and Johansson, Maria C and Wennerberg, Johan and Kjellén, Elisabeth},
  issn         = {1651-226X},
  language     = {eng},
  number       = {2},
  pages        = {205--211},
  publisher    = {Taylor & Francis},
  series       = {Acta Oncologica},
  title        = {Radiation effects on S-phase duration, labelling index, potential doubling time and DNA distribution in head and neck cancer xenografts},
  url          = {http://dx.doi.org/10.3109/02841869509093957},
  volume       = {34},
  year         = {1995},
}