Growth in vivo of l5178y-r murine leukaemic cells treated in vitro with cis-dichloro bis-(cyclopentylamine) platinum II.

ROSENBERG (1977) put forward a hypothesis concerning the mechanism of anticancer activity of cis-platinum complexes in vivo. According to this hypothesis, the simple cytotoxic effect is accompanied by an enhanced expression of cancer antigens on the surface of malignant cells. Therefore, the observed regression of malignant growth is at least partly due to the immunological response of the organism. An example supporting this assumption is the growth kinetics of ascites sarcoma 180 in ICR mice after injection of cis-dichlorodiammine cis-platinum (Rosenberg, 1978). For 4 days following injection the number of tumour cells increases. From the 5th day it falls, reaching zero in a cured animal. According to Rosenberg, this result is consistent with the suggestion that surviving cells are destroyed by the immune system. The hypothesis implies the existence of a ready defensive mechanism which can be stimulated by cisplatin-induced changes in the malignant cell surface. In an attempt to test this hypothesis, we used cis-dichloro bis-(cyclopentylamine) platinum (II) (cis-PAD) and L5178Y-R murine leukaemic cells. These cells are very sensitive to cis-PAD in vitro (Szumiel, 1979) and form ascites tumours in DBA/2 mice. The Pt complex is effective in vivo in mice against leukaemi

Nucleosomes indicate the in vitro radiosensitivity of irradiated bronchoepithelial and lung cancer cells

Nucleosomes, which are typical cell death products, are elevated in the serum of cancer patients and are known to rapidly increase during radiotherapy. As both normal and malignant cells are damaged by irradiation, we investigated to which extent both cell types contribute to the release of nucleosomes. We cultured monolayers of normal bronchoepithelial lung cells (BEAS-2B, n = 18) and epithelial lung cancer cells (EPLC, n = 18), exposed them to various radiation doses (0, 10 and 30 Gy) and observed them for 5 days. Culture medium was changed every 24 h. Subsequently, nucleosomes were determined in the supernatant by the Cell Death Detection-ELISA(plus) ( Roche Diagnostics). Additionally, the cell number was estimated after harvesting the cells in a second preparation. After 5 days, the cell number of BEAS-2B cultures in the irradiated groups (10 Gy: median 0.03 x 10(6) cells/culture, range 0.02-0.08 x 10(6) cells/culture; 30 Gy: median 0.08 x 10(6) cells/culture, range 0.02-0.14 x 10(6) cells/culture) decreased significantly (10 Gy: p = 0.005; 30 Gy p = 0.005; Wilcoxon test) compared to the non-irradiated control group (median 4.81 x 10(6) cells/culture, range 1.50-9.54 x 10(6) cells/culture). Consistently, nucleosomes remained low in the supernatant of nonirradiated BEAS-2B. However, at 10 Gy, BEAS-2B showed a considerably increasing release of nucleosomes, with a maximum at 72 h ( before irradiation: 0.24 x 10(3) arbitrary units, AU, range 0.13-4.09 x 10(3) AU, and after 72 h: 1.94 x 10(3) AU, range 0.11-5.70 x 10(3) AU). At 30 Gy, the release was even stronger, reaching the maximum earlier (at 48 h, 11.09 x 10(3) AU, range 6.89-18.28 x 10(3) AU). In non-irradiated EPLC, nucleosomes constantly increased slightly. At 10 Gy, we observed a considerably higher release of nucleosomes in EPLC, with a maximum at 72 h (before irradiation: 2.79 x 10(3) AU, range 2.42-3.80 x 10(3) AU, and after 72 h: 7.16 x 10(3) AU, range 4.30-16.20 x 10(3) AU), which was more than 3.5 times higher than in BEAS-2B. At 30 Gy, the maximum (6.22 x 10(3) AU, range 5.13-9.71 x 10(3) AU) was observed already after 24 h. These results indicate that normal bronchoepithelial and malignant lung cancer cells contribute to the release of nucleosomes during irradiation in a dose-and time-dependent manner with cancer cells having a stronger impact at low doses. Copyright (C) 2004 S. Karger AG, Basel

Nucleosomes in pancreatic cancer patients during radiochemotherapy

Nucleosomes appear spontaneously in elevated concentrations in the serum of patients with malignant diseases as well as during chemo- and radiotherapy. We analyzed whether their kinetics show typical characteristics during radiochemotherapy and enable an early estimation of therapy efficacy. We used the Cell Death Detection Elisaplus ( Roche Diagnostics) and investigated the course of nucleosomes in the serum of 32 patients with a local stage of pancreatic cancer who were treated with radiochemotherapy for several weeks. Ten of them received postsurgical therapy, 21 received primary therapy and 1 received therapy for local relapse. Blood was taken before the beginning of therapy, daily during the first week, once weekly during the following weeks and at the end of radiochemotherapy. The response to therapy was defined according to the kinetics of CA 19-9: a decrease of CA 19-9 650% after radiochemotherapy was considered as `remission'; an increase of >= 100% ( which was confirmed by two following values) was defined as `progression'. Patients with `stable disease' ranged intermediately. Most of the examined patients showed a decrease of the concentration of nucleosomes within 6 h after the first dose of radiation. Afterwards, nucleosome levels increased rapidly, reaching their maximum during the following days. Patients receiving postsurgery, primary or relapse therapies did not show significant differences in nucleosome values during the time of treatment. Single nucleosome values, measured at 6, 24 and 48 h after the application of therapy, could not discriminate significantly between patients with no progression and those with progression of disease. However, the area under the curve of the first 3 days, which integrated all variables of the initial therapeutic phase, showed a significant correlation with the progression-free interval ( p = 0.008). Our results indicate that the area under the curve of nucleosomes during the initial phase of radiochemotherapy could be valuable for the early prediction of the progression-free interval. Copyright (C) 2005 S. Karger AG, Basel

The contribution of DNA ploidy to radiation sensitivity in human tumour cell lines

The contribution of DNA ploidy to radiation sensitivity was investigated in a group of eight human tumour cell lines. As previous studies suggest, while more aneuploid tumours tend to be more radioresistant, there is no significant relationship between ploidy and radiation sensitivity (SF2). The failure to observe a significant effect of ploidy on radiation sensitivity is due to the complex and multifactorial basis of radiation sensitivity. When we determined the relationship between survival and radiation-induced chromosome aberration frequency, a measure independent of most other modifiers of sensitivity, we observed a direct relationship between ploidy and mean lethal aberration frequency. The mean lethal frequency of aberrations increased from about 1 for diploid cells to about 2 for tetraploid cells. The mean lethal frequency of aberrations was independent of DNA repair variations. These observations demonstrate that changes in DNA ploidy are an important contributor to radiation sensitivity variations in human tumour cell lines. Therefore, any battery of predictive assays should include DNA ploidy measurements. © 1999 Cancer Research Campaig

The effect of radio-adaptive doses on HT29 and GM637 cells

<p>Abstract</p> <p>Background</p> <p>The shape of the dose-response curve at low doses differs from the linear quadratic model. The effect of a radio-adaptive response is the centre of many studies and well known inspite that the clinical applications are still rarely considered.</p> <p>Methods</p> <p>We studied the effect of a low-dose pre-irradiation (0.03 Gy – 0.1 Gy) alone or followed by a 2.0 Gy challenging dose 4 h later on the survival of the HT29 cell line (human colorectal cancer cells) and on the GM637 cell line (human fibroblasts).</p> <p>Results</p> <p>0.03 Gy given alone did not have a significant effect on both cell lines, the other low doses alone significantly reduced the cell survival. Applied 4 h before the 2.0 Gy fraction, 0.03 Gy led to a significant induced radioresistance in GM637 cells, but not in HT29 cells, and 0.05 Gy led to a significant hyperradiosensitivity in HT29 cells, but not in GM637 cells.</p> <p>Conclusion</p> <p>A pre-irradiation with 0.03 Gy can protect normal fibroblasts, but not colorectal cancer cells, from damage induced by an irradiation of 2.0 Gy and the application of 0.05 Gy prior to the 2.0 Gy fraction can enhance the cell killing of colorectal cancer cells while not additionally damaging normal fibroblasts. If these findings prove to be true in vivo as well this may optimize the balance between local tumour control and injury to normal tissue in modern radiotherapy.</p