Human Tumor Primary Cultures Research Articles

Lack of a correlation between p53 protein expression and radiation response in human tumor primary cultures.

We investigated the possible relationship between immunohistochemically detected p53 expression and in vitro response to gamma-irradiation in 24 primary cultures of human ovarian cancers and cutaneous melanomas. The frequency of p53-positive tumors was around 60% within each tumor histotype. The range of the surviving fraction at 2 Gy (SF2) was similar in p53-positive (0.10-0.76) and p53-negative (0.23-0.65) tumors, with median values of 0.36 and 0.33, respectively. No differences were observed in the accumulation of DNA-double strand breaks, assessed by neutral filter elution after exposure to 50 Gy, between p53-positive and p53-negative tumors. As regards DNA lesion repair, after 2 h of recovery the percentage of rejoined DNA-double strand breaks ranged from 19% to 99% in the different cultures, but again the distribution of values was similar for p53-positive and p53-negative tumors. Specifically, the median percentage of repaired DNA-double strand breaks was 70% and 74% in the two groups. On the whole, our data do not support the hypothesis that p53 overexpression is a major determinant of in vitro radiation response.

DNA double-strand break repair and radiation response in human tumour primary cultures.

The accumulation and repair of radiation-induced DNA double-strand breaks (dsbs) were determined by neutral filter elution on 20 primary cultures obtained from ovarian cancer and malignant melanoma clinical specimens. The initial frequency of DNA dsbs after exposure to 50 Gy gamma-irradiation varied greatly for the individual cultures. However, melanomas were generally more efficient than ovarian cancers in repairing these DNA lesions (mean percentage of DNA dsb rejoined after 2 h: 83 versus 62%). In 13 of 20 cultures radiosensitivity was also assessed by the Courtenay clonogenic assay. The mean +/- SD of the surviving fraction at 2 Gy (SF2) was slightly higher for melanomas (0.56 +/- 0.25) than for ovarian carcinomas (0.43 +/- 0.23). No correlation was observed between SF2 and in vitro plating efficiencies or any biological characteristics of the tumour cell population, such as proliferative activity and DNA ploidy. Similarly, we failed to find any relation between the initial frequencies of DNA dsbs and SF2 in individual tumours. In contrast, a significant and direct relationship (r = 0.86, p < 0.01) was observed between SF2 and the percentages of DNA dsbs rejoined 2 h after irradiation. In agreement with reported data on human tumour established cell lines, our results indicate that the ability to repair DNA dsbs is an important determinant for radiation response even in primary cultures of clinical tumours.

Radiosensitivity testing of human tumor primary cultures

Radiosensitivity testing of human tumor primary cultures

Characterization of cell types in human breast tumor primary cultures

Primary cultures of cells from breast carcinomas were attempted in 74 cases. Growth was observed in 46 cases. Using immunochemical demonstration of keratin proteins (KER), epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), three morphologically distinct cell populations were characterized and described. Two cell types (E- and E'-cells) were identified as epithelial by their positive staining for KER and EMA. The third type (F cells) displayed a negative staining for these two epithelial markers; they were considered as stromal cells (fibroblasts). More than 50% of the cultures consisted of pure epithelial cells. Positive CEA staining was observed only in KER- and EMA-positive cells. Out of the 30 cultures, 15 displayed positive staining for CEA. In 7 of these, 30-50% of cells displayed positive, diffuse staining for CEA. The other 8 cultures consisted of more than 50% CEA-positive cells. Strong and homogeneous positivity was restricted to the E-cells, while in the same cultures, E'-cells displayed heterogeneous and diffuse staining. Efficiency and value of this cell culture system are discussed, in comparison with other human breast tumor cell (HBTC) culture techniques. Identification of growing cells and cellular composition of primary cultures are emphasized.