Mamet R, Teitz Y, Schoenfeld N
Laboratory of Biochemical Pharmacology, Beilinson Medical Center, Petah-Tiqua, Israel.
Biochem Med Metab Biol. 1994 Jun;52(1):53-7. doi: 10.1006/bmmb.1994.1033.
The relationship between growth rate and various parameters of the heme biosynthetic pathway was studied in two cell lines of rat fibroblasts (REabl-1 and REabl-3) transfected with v-abl oncogene, coded by the Abelson murine leukemia virus, and subjected to glucocorticoid dependent transformation. In the REabl-1 cell line, whose growth rate was only slightly affected by dexamethasone (DX), almost no change was noticed either in heme content or in the enzymatic activities of aminolevulinate synthase (ALAS), porphobilinogen deaminase (PBGD), and ferrochelatase (FC) in the presence of various concentrations of DX. In the REabl-3 cell line, exhibiting a growth rate highly sensitive to DX, a significant reduction in intracellular heme concomitantly with decreases in ALAS and FC activities and a threefold increase in PBGD were noted. The fact that incubation with 10(-5)M hemin did not result in a decrease in ALAS activity raised the possibility that REabl cells lack a negative feedback control mechanism. The relationships between transformation, growth rate, and heme biosynthetic pathway are discussed.
在两种转染了由阿贝尔森鼠白血病病毒编码的v-abl癌基因并经历糖皮质激素依赖性转化的大鼠成纤维细胞系（REabl-1和REabl-3）中，研究了生长速率与血红素生物合成途径各种参数之间的关系。在REabl-1细胞系中，其生长速率仅受到地塞米松（DX）的轻微影响，在存在不同浓度DX的情况下，血红素含量以及氨基乙酰丙酸合酶（ALAS）、胆色素原脱氨酶（PBGD）和亚铁螯合酶（FC）的酶活性几乎没有变化。在REabl-3细胞系中，其生长速率对DX高度敏感，观察到细胞内血红素显著减少，同时ALAS和FC活性降低，而PBGD增加了三倍。用10^(-5)M血红素孵育并未导致ALAS活性降低，这一事实增加了REabl细胞缺乏负反馈控制机制的可能性。文中讨论了转化、生长速率和血红素生物合成途径之间的关系。
