PubMed Health⌕ Search

Biomedical subjects

B Dutrillaux

Publications and source records attributed to B Dutrillaux.

At least 19 recordsLinked to original sources
PubMed1992

Chromosomal anomalies in radiation-induced fibrosis in the pig.

R-banded karyotypes were established on fibroblasts from fibrotic tissues derived from experimental fibrosis induced in pigs, either surgically or by 64 Gy of gamma-rays from iridium-192. No chromosome aberrations were observed in the surgical fibrosis. In radiation-induced fibrosis, the high frequency of abnormal karyotypes and the frequent complexity of the chromosomal rearrangements suggest that the fibroblasts originated either from the 64-Gy area, or from the penumbra, but certainly not from non-irradiated areas. At early passages in vitro, almost all karyotypes were different, demonstrating a multiclonal origin of fibrotic tissue. At late passages (above 24), the situation was quite different, with the persistence of one or two clones only, demonstrating a strong selective pressure occurring in vitro.

Animals↗
PubMed1992

Early superoxide dismutase alterations during SV40-transformation of human fibroblasts.

The expression of superoxide dismutases (SOD) 1 and 2 was studied in 4 clones of human fibroblasts after their infection by simian virus 40 (SV40), in parallel with the alterations of chromosomes 21 and chromosome 6q arms, carrying the genes that encode for SOD1 and SOD2 respectively. For all clones, a similar scheme with 2 main phases was observed for both chromosome and SOD variations. The first phase, defined as the pre-crisis phase, was characterized by chromosomal instability, but maintenance of normal numbers of chromosome 6q arms and chromosomes 21. The level of SOD2 mRNA was high, while SOD2 activity and immunoreactive protein were low. SOD1 protein and activity were decreased. In the second phase, defined as the post-crisis phase, the accumulation of clonal chromosomal rearrangements led to the loss of 6q arms, while the number of chromosomes 21 remained normal. SOD2 mRNA level was decreased and SOD2 immunoreactive protein and activity remained low. SOD1 protein and activity increased with passages, reaching values similar to those of control cells at late passages. As in established SV40-transformed human fibroblast cell lines, good correlation was found between SOD2 activity and the relative number of 6q arms. These results allow us to reconstruct the sequence of events leading to the decrease of SOD2, a possible tumor-suppressor gene, during the process of SV40-transformation of human fibroblasts.

Cell Transformation, Viral↗
PubMed1992

Single-steep transformation of human breast epithelial cells by SV40 large T oncogene.

Normal human mammary epithelial cell (HMEC) cultures originating from 2 mammoplasty reduction surgical samples were transfected with replication-defective SV 40 DNA. Two independent cell lines designated as S2T2 and S1T3, selected for their increased proliferation potential and lifespan, were propagated for greater than 22 months in culture. They maintained a near-diploid karyotype with few chromosomal markers such as trisomy 1q (S1T3) and trisomy 8q (S2T2), which are most common in breast cancer in vivo. Immortalized S1T3 cells were not tumorigenic, whereas S2T2 cells produced slowly growing tumors in nude mice. One tumor was propagated in vitro and the transformed NS2T2 cell line subsequently raised 100% large tumors in the nude mouse. Rearrangement of the SV40 genome was observed in NS2T2 cells, which was not associated with increased expression of large T antigen. S1T3, S2T2 and transformed NS2T2 cell lines expressed cytokeratins CK18, CK19, the mammary-specific antigen DF3, and functional EGF receptors. Single-step immortalization and malignant transformation of human breast epithelial cells can thus occur upon transfection with SV40 large T oncogene. The chromosomal abnormalities observed in these cell lines suggest that they could offer a model for the study of breast-tumor progression in vitro.

Adult↗
PubMed1992

Jumping translocations originate clonal rearrangements in SV40-transformed human fibroblasts.

A comparative study of chromosomal rearrangements occurring in 4 independent clones obtained from SV40-transformed cornea and skin human fibroblasts was performed. Rearrangements principally affect some constitutive heterochromatin and, to a lesser degree, telomeric regions. This results in multiple exchanges between a limited number of chromosome structures, i.e., in jumping translocations. Such rearrangements occur even at early passages and some of them give rise to clonal rearrangements that accumulate at late passages. This process is responsible for progressive modification of the karyotypes, principally characterized by deletion of a number of chromosome segments. Thus, clonal rearrangements are selected among many others not occurring at random. The selective pressure retaining clonal rearrangement seems to be similar for the 4 independent clones, since selection of the derivative chromosomes leads to the same imbalances, whatever the origin of the clone. This sequence of events recalls that of human solid tumors, since jumping rearrangements are generally observed in pre-malignant conditions or in low-grade malignancies, whereas clonal rearrangements leading to typical imbalances are detected in more advanced malignant tumors.

Cell Transformation, Neoplastic↗
PubMed1992

Constitutional balanced translocations in patients with solid tumors.

In a sample of 329 patients with a solid tumor (colon and breast adenocarcinoma, cervical carcinoma, and meningioma), four balanced constitutional translocations were observed. Two were t(13q14q), and two were reciprocal translocations. Comparison with surveys of newborns showed a significant excess of translocations in our sample.

Adenocarcinoma↗
PubMed1992

SOD2: a new type of tumor-suppressor gene?

The activity of superoxide dismutases (SOD) 1 and 2 was analysed in correlation with mRNA and chromosome content in 6 SV40-transformed (TF) and in non-transformed (NF) human fibroblast cell lines. Total SOD activity was fairly constant, whereas the ratio SOD2/SOD1 was much lower in TF than in NF. The decrease in SOD2 activity was correlated with a low mRNA content, and with the presence of various chromosomal rearrangements leading to deletions of the long arm of chromosome 6 where the gene is mapped. In contrast, chromosome 21, carrying the gene for SOD1, was not found to be deficient and the SOD1 activity was high. This shows that in TF, the activity of SOD2 is largely determined by gene dosage. It has been proposed that SOD activity could be inversely correlated with cell proliferation, and that SOD2 activity, in particular, was related to cell differentiation. Thus, there is a cascade of events occurring in cell transformation, involving gene deregulation, chromosome (gene) deletion, low mRNA and protein content, low enzyme activity, and acquisition of growth advantage which makes the SOD2 gene a possible new type of tumor-suppressor gene.

Cell Line, Transformed↗
PubMed1992

Spontaneous metastatic potential of rat hepatocarcinoma cells after cell fusion or DNA transfection.

Eight LF x ICIG cell hybrid clones, isolated upon fusion of normal ICIG-7 human fibroblasts with tumorigenic, non-metastatic LF Cl.2A cells derived from a DAB-induced rat hepatocarcinoma, were studied. They were all highly tumorigenic and were capable of developing spontaneous lung metastases in syngeneic animals. All the hybrids were characterized by a rapid loss of human chromosomes. However, in long-term culture, they all revealed a persistence of human genetic information as assessed by Southern blotting. In hybrid lines in which human chromosomes were still visible, the most recurrent were numbers 7 and 9. Neither chromosome 7, previously reported to bear some of the genes controlling metastasis in human X mouse T-cell hybrids, nor chromosome 9 appeared to be correlated with the metastatic potential of LF X ICIG hybrids. The same conclusion applied (1) to a human 3.3-kb EcoRI DNA fragment which was amplified (approx. 10-fold) only in metastases induced by one out of 3 metastatic hybrids tested; (2) to the transcription level of c-Ha-ras and c-Ki-ras genes which was enhanced (approx. 4-fold) in metastatic and non-metastatic lines as well. Co-transfection of LF Cl.2A cells with pHSG 272 selectable marker DNA and genomic DNA from normal ICIG-7 human cells or from a hybrid-induced metastasis, reproducibly gave rise to geneticin-resistant transfectants capable of producing spontaneous lung metastases. Neither transfectants nor transfectant-induced metastases harbored detectable human DNA sequences but all harbored pHSG 272 DNA. These results again call for caution in gene transfer studies of the metastatic process.

Animals↗
PubMed1992

Proliferative activity of breast cancers increases in the course of genetic evolution as defined by cytogenetic analysis.

The prognostic value of proliferative activity and its relationship with steroid hormone receptors and histopathological grade have been demonstrated for breast cancers. However, nothing is known about the underlying mechanisms. In order to understand the chronology of the appearance of increased proliferative activities, we used a series of 760 consecutive breast cancers for which we had obtained S-phase fractions (SPFs) by DNA flow cytometry. When the absolute difference from a DNA index of 1.00 was compared to SPFs, a significant positive correlation was obtained (r = 0.39, p < 0.0001), indicating that the probability of observing a high SPF increases when tumors progressively deviate from diploidy. A highly significant correlation was observed for the hyperploid group when hypertetraploid tumors were excluded, as the SPFs increased progressively as the DNA indices decreased from 2.00 to 1.30. This observation suggested a relationship with the evolution of chromosomal abnormalities as determined by cytogenetic analysis. Indeed, in a subset of 52 cases for which sufficient metaphases were available, there was a highly significant correlation between the SPF values and the proportion of rearranged chromosomes in the tumor cells (r = 0.60, p < 0.0001). When SPFs were separated into low or high using the median value (4.5%), a correlation also existed with the genetic evolution, since they increased from diploidy to hypodiploidy and then, after endoreduplication, from tetraploidy towards triploidy, as determined by the chromosome counts. Our results substantiate the relationship between proliferative activity and steroid hormone receptors which follow the same model.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Evolution↗
PubMed1992

Genetic evolution of breast cancer: II. Relationship with estrogen and progesterone receptor expression.

The expression of estrogen (ER) and progesterone (PR) receptors was assayed by steroid binding in a series of 95 malignant breast tumors, for which the analysis of chromosome aberrations was performed and allowed the reconstruction of their chromosomal evolution. It was shown that breast tumors undergo a progressive loss of chromosomes, with occasionally one and rarely two endoreduplications. Chromosome losses were often the consequence of rearrangements, and the rate of rearranged chromosomes, which increases progressively, appeared as a possible indicator of tumor progression. The distribution of ER and PR values in the sample of 95 tumors was compared to that of a larger control series of consecutive cases: 598 for ER and 460 for PR. The similarities of the distributions indicated that the sample of 95 tumors was representative of the general population of breast cancers. The levels of ER and PR expression were very strongly and negatively correlated to the rate of rearranged chromosomes, but not to the modal number of chromosomes. However, when tumors having either undergone endoreduplication or not (greater than 50 or less than 51 chromosomes, respectively) were considered separately, a significant correlation between ER and PR expression and chromosome number was found within each group. Finally, breast cancers were subdivided into 4 stages of cytogenetic evolution, from the least to the most evolved: stage 1: less than or equal to 50 chromosomes, less than 25% rearranged chromosomes; stage 2: greater than 50 chromosomes, less than 25% rearranged chromosomes; stage 3: less than or equal to 50 chromosomes, greater than 25% rearranged chromosomes; stage 4: greater than 50 chromosomes, greater than 25% rearranged chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1992

Cytogenetic study of breast cancer: clinicopathologic significance of homogeneously staining regions in 84 patients.

A cytogenetic study performed on 84 primary breast cancers was conducted to detect the presence of chromosomes with homogeneously staining regions (HSRs) which are assumed to correspond to gene amplification. Homogeneously staining regions were found in 60% of the cases. To assess the prognostic significance of HSRs, clinical and pathologic data were correlated with the cytogenetic findings. Median follow-up for the 84 patients was 40 months. Differences in overall survival and disease-free survival rates between patients with HSRs (50 cases) and patients without HSRs (34 cases) were not significant. Although an excess of HSRs was found in patients considered to have poor prognostic factors (eg, young age, high histologic grade, metastatic axillary nodes, loss of hormonal receptors), no statistically significant correlation between variables could be demonstrated. The high percentage of cases with HSRs strongly suggests that they have an important biologic role, but more cases should be studied with a longer follow-up to assess their significance.

Adult↗
PubMed1992

Cytogenetic study of five cases of lung adenosquamous carcinomas.

The cytogenetic study of five cases of untreated adenosquamous carcinoma of the lung allows us to propose a number of characteristic anomalies. All tumor cells were hyperdiploid, with a mean chromosome number ranging from 59 to 83, and had many clonal chromosome rearrangements. The chromosomes the most frequently affected by these rearrangements were, by decreasing order, 1, 3, and 15; 7 and 8; and 17. No recurrent breakpoints were observed in euchromatic regions, most breaks (45/66) involving juxtacentromeric heterochromatin or immediately adjacent regions. Although chromosome 3 was frequently rearranged, no recurrent deletions of its short arm were observed.

Adenocarcinoma↗
PubMed1992

Increased p53 protein content of colorectal tumours correlates with poor survival.

Allelic losses on the short arm of chromosome 17 occur frequently in colorectal cancers. Despite the existence of other common molecular events such as loss of the long arms of chromosomes 18 and 5, it has been demonstrated that the former has the greatest prognostic significance. Of the various genes mapping to the commonly deleted sequence, the best candidate as a 'target' seems to be the p53 antioncogene. We applied our methods of detection of the p53 protein in a series of 78 colorectal cancers stored in a tumour bank from 1985 to 1989, for which the median follow-up was 42 months. Nuclear-attached p53 was quantified by flow cytometry and soluble p53 was assayed by ELISA. Both assays used a monoclonal antibody considered to be specific for a conformational epitope present only on the mutated protein. Fifty of the 78 tumours (64%) were found to present significant levels of p53 attached to the nucleus. A further two tumours contained high levels of p53 only in their soluble fraction. Thus, 52 out of 78 cancers (67%) were considered to be positive for p53. The p53 content correlated with 17p loss (P < 0.002), hyperdiploid DNA content (P < 0.001) and tumour site (P < 0.03), but not Dukes' stage (P = 0.15). p53 negative cases had a better overall survival than p53 positive ones (P < 0.03). When the 14 stage D tumours were excluded from the analysis, p53 was no longer significantly predictive of survival (P < 0.07), but remained predictive of recurrence (P < 0.02) and metastasis (P < 0.03). Multivariate analysis was not performed because of the small number of cases. Overall, disease-free and metastasis-free survival were compared to the positivity obtained either with pAb 421 and/or 1801 or pAb 240 since all three were used in the flow cytometric analysis, defining subsets of 421-, 1801+ and 421-, 1801-, 240+. The presence of nuclear protein presenting the mutation-specific epitope, recognised by pAb 240, was found to be the most discriminant. It must be noted that univariate survival analysis demonstrated that more than 80% of patients with p53-negative tumours were alive at 3 years vs less than 50% in the p53-positive group. A large prospective study should be conducted to define the exact prognostic significance of the p53 content of colorectal carcinomas.

Adenocarcinoma↗
PubMed1992

Chromosomal, mitochondrial and metabolic alterations in SV40-transformed rabbit chondrocytes.

Karyotype, mitochondrial ultrastructure and several enzymatic activities were studied in two clones, D22 and D27, from SV40-transformed rabbit chondrocytes. Similar chromosome alterations, with recurrent losses and gains were observed at the various passages. Mitochondria were rare, with increase in size and crest alterations. By comparison to non-transformed rabbit chondrocytes, activities of superoxide dismutase 1 and 2 (SOD) and glutathione peroxidase were increased, those of glutathione reductase, glucose-6-phosphate dehydrogenase and glutathione-S-transferase fluctuated according to passages, thymidylate synthase decreased, thymidine kinase and hypoxanthine-phosphoribosyl-transferase increased and the ratio lactate dehydrogenase B/A increased. In most cases, these variations were correlated with the number of chromosomes carrying the genes encoding for corresponding enzymes. These results, compared to those obtained in SV40-transformed human fibroblasts, demonstrate that the two cell types behave differently for detoxication systems against oxygen radicals, in particular for SOD2 activity, and have opposite imbalances of chromosomes carrying the corresponding genes.

Animals↗
PubMed1992

A simple method for simultaneous R- or G-banding and fluorescence in situ hybridization of small single-copy genes.

A significant improvement in fluorescence in situ hybridization, enabling the detection of single-copy genes as small as 500 bp directly on banded chromosomes, is presented. The induction of chromosome banding, which does not require additional handling or any system of amplification, is obtained simply by using an alkaline (pH 11) p-phenylenediamine anti-fade solution. As the banding produced is related to the timing of 5-bromodeoxyuridine incorporation, either R- or G-banding, constitutive heterochromatin staining, or chromosome asymmetry can be observed simultaneously with the fluorescent hybridized spots. Results of hybridization of small cDNA probes for the human genes for motilin, thymidylate synthetase, and lymphocyte activation-3 are provided as examples of the high-resolution mapping obtainable with this technique.

Cells, Cultured↗
PubMed1992

Detection of small, single-copy genes on protein-G-banded chromosomes by electron microscopy.

A method for the detection by electron microscopy of chromosome banding after in situ hybridization of small, nonradioactive DNA sequences is described. Typical high-resolution G-banding is produced by adding 5-bromodeoxyuridine (BrdU) during the last part of the S-phase and by applying a monoclonal antibody against the BrdU-substituted chromosome segments, followed by the addition of protein G, but no further treatment. A protocol for in situ hybridization of small, single-copy biotinylated DNA sequences and their detection by immunogold tagging on banded chromosomes is also described. This combined approach permits high-resolution mapping of small DNA sequences and should be useful in discriminating between neighboring DNA fragments.

Antibodies, Monoclonal↗
PubMed1992

New gene assignments to rabbit chromosomes; implications for chromosome evolution.

The genes for SOD1 and SOD2 (superoxide dismutases 1 and 2), RB1 (retinoblastoma), TYMS (thymidylate synthase), and TK1 (thymidine kinase) were mapped by in situ hybridization using biotinylated probes to rabbit chromosomes 6, 12, 8, 9, and 19, respectively. This confirms their proposed homoeologies with human chromosomes 21, 6, 13, 18, and 17, respectively, and provides additional information on the modification of these chromosomes during evolution.

Animals↗