Yen A, Sturgill R, Varvayanis S, Chern R
Department of Pathology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
Exp Cell Res. 1996 Nov 25;229(1):111-25. doi: 10.1006/excr.1996.0349.
The effect of the CSF-1 receptor, cFMS, on the phosphorylation of the retinoblastoma (RB) tumor suppressor protein and on the cell cycle and cell differentiation was analyzed in a cultured promyelocytic leukemia cell capable of induced myelomonocytic differentiation. A series of cFMS-transfected HL-60 sublines with progressively higher cell surface FMS expression was derived by flow cytometric cell sorting. Overexpression of FMS increased the duration of the cell cycle, prolonging all cell cycle phases especially S phase, which doubled. The increased cell cycle generation times occurred without any detectable changes in RB expression level or phosphorylation. For retinoic acid (RA)-induced myeloid differentiation, progressive overexpression of FMS caused a greater fraction of cells to differentiate and G1/0 arrest compared to wild-type cells after the same number of cell cycle generation times. FMS overexpression also progressively increased the relative amount of dephosphorylated RB protein induced, while reducing the total amount of RB protein. The inducer-originated and FMS-driven changes in RB hypophosphorylation were not effected through changes in p21/WAF1/CIP1 in this p53-negative cell. Similar effects on differentiation and G0 arrest occurred with 1,25-dihydroxy vitamin D3 (D3)-induced monocytic differentiation. FMS did not significantly affect myeloid differentiation induced by DMSO, which does not target steroid-thyroid hormone receptors like RA and D3. While differentiation is typically associated with hypophosphorylated RB in all these cases, the kinetics indicate that the FMS-induced changes in cell cycle and cell differentiation do not depend in a direct causal fashion on the interconversion between hyperphosphorylated and hypophosphorylated RB.
在一种能够诱导髓单核细胞分化的培养早幼粒细胞白血病细胞中，分析了集落刺激因子-1受体（CSF-1受体，cFMS）对视网膜母细胞瘤（RB）肿瘤抑制蛋白磷酸化、细胞周期和细胞分化的影响。通过流式细胞术细胞分选获得了一系列cFMS转染的HL-60亚系，其细胞表面FMS表达逐渐升高。FMS的过表达增加了细胞周期的持续时间，延长了所有细胞周期阶段，尤其是S期，S期延长了一倍。细胞周期代时增加，但RB表达水平或磷酸化没有任何可检测到的变化。对于维甲酸（RA）诱导的髓系分化，在相同数量的细胞周期代时后，与野生型细胞相比，FMS的逐渐过表达导致更多比例的细胞分化并停滞在G1/0期。FMS过表达还逐渐增加了诱导的去磷酸化RB蛋白的相对量，同时减少了RB蛋白的总量。在这个p53阴性细胞中，RB低磷酸化的诱导物起源和FMS驱动的变化不是通过p21/WAF1/CIP1的变化实现的。1,25-二羟基维生素D3（D3）诱导的单核细胞分化也对分化和G0期停滞产生了类似的影响。FMS对二甲基亚砜（DMSO）诱导的髓系分化没有显著影响，DMSO不像RA和D3那样靶向类固醇-甲状腺激素受体。虽然在所有这些情况下，分化通常与低磷酸化的RB相关，但动力学表明，FMS诱导的细胞周期和细胞分化变化并不直接依赖于高磷酸化和低磷酸化RB之间的相互转化。
