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Two soft-agar methods for assaying chemosensitivity of human cancers in vitro were compared with respect to colony morphology, plating efficiency (PE) and chemosensitivity of human melanomas. In 9 xenografts and 9 patients' biopsy specimens Method A (essentially that of Courtenay & Mills, 1978) gave considerably higher PE that Method B (essentially that of(More)
Multidrug resistance (MDR) to anti-cancer agents is frequently associated with overexpression of the drug efflux transporter P-glycoprotein (Pgp) in cancer cells, ensuing drug expulsion and maintenance of tolerable intracellular levels of certain cytotoxic drugs. Pgp may also be present in normal tissue, providing protection against toxic substances, but(More)
Drug resistance is a major obstacle to successful chemotherapy of primary liver cancer, which is associated with high expression of the multidrug resistance (MDR) gene product P-glycoprotein (Pgp), a multidrug efflux transporter. The most effective single agents in treatment of primary liver carcinoma belong to the anthracycline family, yet several(More)
The role of metallothionein (MT) in the cytotoxicity of tumor necrosis factor (TNF) was investigated in vitro. A human epithelial cell line (HE100) and a mouse fibroblast line (CI 1D100) had previously been cultured to become resistant to 100 microns CdCl2 and were cultured routinely in cadmium-containing medium. The MT content of these cells and the(More)
To investigate the influence of culture conditions on the in vitro responses of tumour cells to anticancer drugs, the sensitivities observed with the soft agar methods of Hamburger & Salmon (1977) (H-S) and of Courtenay & Mills (1978) (C-M) were compared. In all cases the ID50 values were determined from dose-response curves. Six human tumour cell lines(More)
Cultured cells with elevated levels of cytoplasmic metalloidi-onein (MT), a small-molecular-weight protein extremely rich in cysteine. showed resistance against the alkylating drug chlor-ambucil. One human epithelial line (HE) and one mouse fibroblast line (CI 1D) were used, as well as substrains of both cell lines (HE10oand CI 1D10o).The substrains contain(More)
Repeated i.p. injections of the synthetic peptides pyroglutamylgluta-mylglycylserylasparagine and pyroglutamylglutamylglycylserylaspartic acid inhibited the long-term growth of MHiCi rat hepatoma cells by 50-70% in three in vivo models: metastatic colony growth in the lungs of young Buffalo rats; s.c. tumor growth in young Buffalo rats; and s.c. tumor(More)
Cultured cells have been made resistant to otherwise lethal concentrations of the toxic Cd ion, probably by induction of metallothionein (MT) synthesis and binding of Cd to the MT. One human epithelial cell line (HE) and two enzyme-deficient mutants of mouse fibroblasts (L-cells) (Cl 1D and A9) and their Cd-resistant substrains with a high content of MT,(More)
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