Use of fluorescence in situ hybridization (fish) to study chromosomal damage induced by radiation and bromodeoxyuridine in human colon cancer cells

Wilt, Stephen R.; Burgess, Ann C.; Normolle, Daniel P.; Trent, Jeffrey M.; Lawrence, Theodore S.

doi:10.1016/0360-3016(94)90361-1

Cited by 8 publications

(4 citation statements)

References 17 publications

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“…Because we had hypothesized that changes in cell cycle distribution could occur from wt p53 expression, we examined the cell cycle distribution of both our control and study cell populations. Cells from the ts29-A, ts29-G, and HT29neo cell lines that were grown at the nonpermissive temperature showed a flow cytogram pattern similar to the one we have reported previously for parental HT29 cells [18]. At the permissive temperature of 32°C, ts29-A and ts29-G cells evidenced a significant depletion of cells in S-phase and a significant increase in the fraction of cells in G 2 /M-phase.…”

Section: Resultssupporting

confidence: 82%

“…Hartwell and Kastan have hypothesized that there is a biologically significant level of spontaneous DNA damage that requires checkpoint control in order for cells to maintain a high fidelity of chromosome transmission [23]. It is consistent with this model that HT29 cells, which have a highly abnormal karyotype [18], would undergo apoptosis as a result of wt p53 expression. However, apoptosis accounts for only a fraction of the of the loss of clonogenicity, so its importance in this system remains unclear.…”

Section: Discussionmentioning

confidence: 75%

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Effect of p53 overexpression on radiation sensitivity of human colon cancer cells

Zellars

Naida

Davis

et al. 1997

Radiat. Oncol. Investig.

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Substantial controversy surrounds our understanding of the effect of p53 status on radiation sensitivity. To assess directly the role of p53 expression on radiation sensitivity, we chose a conditional expression system using a temperature‐sensitive murine p53 that permitted each cell line to act as its own control. We found that the conditional expression of wild type p53 induced cell death (both apoptotic and nonapoptotic), changes in cell cycle distribution (arrest in G1 and G2, which resulted in a marked depletion of S‐phase cells and an increase in the fraction of cells in G2), and an increase in the radiation resistance of G1 cells. These counterbalancing effects resulted in no significant effect on overall radiosensitivity. These findings demonstrate that wild type p53 function can produce a variety of effects that can modulate radiation sensitivity and may explain why p53 status alone has not been a strong predictor of radiosensitivity. Radiat. Oncol. Invest. 5:43–49, 1997. © 1997 Wiley‐Liss, Inc.

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Section: Resultssupporting

confidence: 82%

Section: Discussionmentioning

confidence: 75%

Effect of p53 overexpression on radiation sensitivity of human colon cancer cells

Zellars

Naida

Davis

et al. 1997

Radiat. Oncol. Investig.

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“…However, it is possible that the heterogeneity of response to FdUrd seen in the present study could be due to variation among members of the parental HT29 population with regard to factors regulating arrest at the G1/S border that are downstream of p53, such as waf1/cip1 or Rb protein [8]. The existence of stable subpopulations in other human tumor cell lines has been demonstrated previously [14], and cytogenetic data indicate that the parental HT29 population used in the present study does contain a significant cohort of cells which have karyotypic markers that differ from the majority of the population [15]. We are therefore pursuing further studies to determine if there are stable HT29 subpopulations which could account for the heterogeneous response pattern reported here.…”

Section: Discussionsupporting

confidence: 62%

Dependence of fluorodeoxyuridine-induced cytotoxicity and megabase DNA fragment formation on S phase progression in HT29 cells

Tang

Weber

Lawrence

et al. 1996

Cancer Chemother Pharmacol

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The relationship between cell cycle progression and induction of DNA double-strand breaks and cytotoxicity by exposure to fluorodeoxyuridine (FdUrd) was studied in HT29 human colon cancer cells. Fractionation of drug-treated populations by centrifugal elutriation yielded subpopulations having widely divergent abilities to progress through S phase in the presence of the drug. One of these subpopulations, which appeared to undergo coordinated growth arrest, was resistant to FdUrd cytotoxicity and DNA damage. In contrast, the subpopulation which was able to progress furthest through S phase in the presence of FdUrd underwent unbalanced growth arrest (i.e., increase in size and mass out of proportion to DNA synthesis), and displayed both DNA double-strand break formation (assayed by pulsed field gel electrophoresis) and loss of clonogenicity. When cells were elutriated prior to drug treatment, producing fractions enriched in cells at various cell cycle stages, no significant differences in sensitivity to FdUrd-induced cytotoxicity were detected among elutriation fractions. These findings support the model that, in HT29 cells, progression into and through S phase during drug treatment is an important determinant of FdUrd-induced DNA damage and cytotoxicity, but that the cell cycle position at the start of drug exposure is not a critical factor for these effects.

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“…Next, we compared the number of breaks observed for chromosomes containing or not containing plasmid with or without telomeric repeats and found that, even if chromosomes 4 and 7 are more often broken, no significant difference could be observed either in the transfected cell lines or in the parental one. These results indicate a preferential breakage of some chromosomes rather than an effect of transfected sequences, as already described for normal chromosome 4 (Wilt et al, 1994;Boei et al, 1997). More breaks than expected occurred within the regions containing integrated plasmid sequences regardless of whether they contained telomeric repeats or not.…”

Section: Discussionsupporting

confidence: 61%

Interstitial telomeric repeats are not preferentially involved in radiation-induced chromosome aberrations in human cells

Desmaze

Pirzio²,

Blaise³

et al. 2004

Cytogenet Genome Res

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Telomeric repeat sequences, located at the end of eukaryotic chromosomes, have been detected at intrachromosomal locations in many species. Large blocks of telomeric sequences are located near the centromeres in hamster cells, and have been reported to break spontaneously or after exposure to ionizing radiation, leading to chromosome aberrations. In human cells, interstitial telomeric sequences (ITS) can be composed of short tracts of telomeric repeats (less than twenty), or of longer stretches of exact and degenerated hexanucleotides, mainly localized at subtelomeres. In this paper, we analyzed the radiation sensitivity of a naturally occurring short ITS localized in 2q31 and we found that this region is not a hot spot of radiation-induced chromosome breaks. We then selected a human cell line in which approximately 800 bp of telomeric DNA had been introduced by transfection into an internal euchromatic chromosomal region in chromosome 4q. In parallel, a cell line containing the plasmid without telomeric sequences was also analyzed. Both regions containing the transfected plasmids showed a higher frequency of radiation-induced breaks than expected, indicating that the instability of the regions containing the transfected sequences is not due to the presence of telomeric sequences. Taken together, our data show that ITS themselves do not enhance the formation of radiation-induced chromosome rearrangements in these human cell lines.

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Use of fluorescence in situ hybridization (fish) to study chromosomal damage induced by radiation and bromodeoxyuridine in human colon cancer cells

Cited by 8 publications

References 17 publications

Effect of p53 overexpression on radiation sensitivity of human colon cancer cells

Effect of p53 overexpression on radiation sensitivity of human colon cancer cells

Dependence of fluorodeoxyuridine-induced cytotoxicity and megabase DNA fragment formation on S phase progression in HT29 cells

Interstitial telomeric repeats are not preferentially involved in radiation-induced chromosome aberrations in human cells

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