Human tumour clonogenicity in agar is improved by cell-free ascites

Abstract

Summary Replacement of enriched CMRL 1066 medium by cell-free ascites from tumour patients in the human tumour clonogenic assay described by Hamburger and Salmon (1977) increased plating efficiency for ovarian cancer cells by a median of 8-fold (range 0.4-1012 fold). In 40 experiments, two cases had a lower plating efficiency when cultured in cell-free ascites, 10 grew neither in standard medium nor in cell-free ascites and in two cases, growth was only observed in cell-free ascites. With standard medium, we observed 53% growth (>5 colonies/dish) and 41% evaluable for chemosensitivity testing (>30 colonies/dish). With cell-free ascites as culture medium, these figures were 71% and 63%, respectively. While under standard conditions the highest plating efficiency obtained was 0.25%, in 21% of the experiments done with cell-free ascites a plating efficiency higher than 1% was reached. We conclude that cell-free ascites is able to stimulate proliferation of ovarian cancer cells in agar and that the use of it extends the applicability of the clonogenic assay.

A comparison of two culture techniques: An in vitro & an in vivo tumour colony-forming assay

“…Several ways to optimize culture conditions have been investigated: the application of a low oxygen concentration, the replenishment of the medium at weekly intervals, the addition of feeder cells or cellfree ascites fluid. The addition of 25% cell-free ascites fluid has repeatedly been found to result in better growth by others (Uitendaal et al, 1983), as well as ourselves (unpublished observations). Nevertheless, in vitro assays are frequently hampered by insufficient growth.…”

Mesothelial cells stimulate the anchorage-independent growth of human ovarian tumour cells

“…Colony stimulating activity of cell-free ascites and serum from the same patient The colony stimulating activity (CSA) of cell-free ascites for TC has been described by others (Uitendaal et al, 1983;Broxterman et al, 1987). The supposition that preferential growth of ovarian cancer in the coelomic cavities is due to locally produced growth factors implies that there should be a difference in the growth promoting properties of serum and ascites, and paired samples of serum and ascites from the same patient were therefore tested for CSA, using OAW 42 as target cells.…”

“…It was originally hypothesised that locally produced factors could contribute to the restricted pattern of spread of ovarian cancer and the finding that MC can stimulate the clonogenic growth of ovarian TC supports this idea. Ascitic fluids from cancer patients also possess colony stimulating activity for some TC (Uitendaal et al, 1983;Broxterman et al, 1987) and this may be due to conditioning of the fluid by MC and/or TC. Although human serum/plasma also promoted clonogenic growth of TC above control levels (GM) in 3/7 samples tested, it was interesting to observe that the colony stimulating activity of serum was appreciably lower than ascitic fluid from the same patient in 5/7 pairs tested.…”

Growth promoting properties of cell free malignant ascites and benign peritoneal fluid on epithelial ovarian carcinoma cells in culture

“…Until now, in vitro evidence in support of this hypothesis has been circumstantial, since in previous experiments the mitogenic potential of cell free malignant ascites has been measured on target cultures composed of immortalized cell lines which may not reflect the receptor distribution of the cells in vivo. Studies using the human tumor clonogenicity assay (26) have demonstrated increased growth stimulation of primary explants of ovarian carcinoma cells by ascites but have not shown this with cells and fluid from the same patient. Ovarian carcinoma colony stimulation under anchorage-independent conditions (27) has shown stimulation of tumor cell lines by both malignant and benign peritoneal fluid but with no significant difference between them.…”