Okabe J, Honma Y, Hayashi M, Hozumi M
Int J Cancer. 1979 Jul 15;24(1):87-91. doi: 10.1002/ijc.2910240115.
Resistant mouse myeloid leukemia cells could not be induced to differentiate in vitro into mature macrophages and granulocytes by incubation with ascitic fluid or dexamethasone as inducer. Neither could endogenous inducers acting on resistant cells maintained in a diffusion chamber in syngeneic SL mice induce differentiation. However, when resistant cells were pretreated in vitro with low doses of actinomycin D they became sensitive to inducer in vitro or in vivo. The concentration of actinomycin D effective for this effect did not induce differentiation. The effect of actinomycin D was not due to inhibition of cell growth, since sensitivity was not observed when resistant cells were pretreated with the growth inhibitor 5-fluorodeoxyuridine. When resistant cells were kept in a diffusion chamber in mice injected with low doses of actinomycin D they showed significant differentiation, suggesting that the in vivo effect of actinomycin D is partly attributable to sensitization of the resistant cells to endogenous inducers.
耐药小鼠髓系白血病细胞在与腹水或地塞米松作为诱导剂孵育时，无法在体外被诱导分化为成熟的巨噬细胞和粒细胞。作用于同基因SL小鼠扩散室中维持的耐药细胞的内源性诱导剂也不能诱导分化。然而，当耐药细胞在体外先用低剂量放线菌素D预处理时，它们在体外或体内对诱导剂变得敏感。对这种效应有效的放线菌素D浓度不会诱导分化。放线菌素D的作用不是由于抑制细胞生长，因为当耐药细胞用生长抑制剂5-氟脱氧尿苷预处理时未观察到敏感性。当耐药细胞置于注射低剂量放线菌素D的小鼠的扩散室中时，它们显示出明显的分化，这表明放线菌素D的体内效应部分归因于耐药细胞对内源性诱导剂的致敏。
