Landolfo S, Guarini A, Riera L, Gariglio M, Gribaudo G, Cignetti A, Cordone I, Montefusco E, Mandelli F, Foa R
Centro CNR di Immunogenetica ed Oncologia Sperimentale, University of Torino, Torino, Italy.
Hematol J. 2000;1(1):7-14. doi: 10.1038/sj.thj.6200004.
Interferon-alpha (IFN) plays a role in the management of different neoplasias, particularly those of hematological origin. The mechanisms of action of IFN are still poorly understood and the individual response is unpredictable. In the present study, the pattern of intracellular gene expression following in vitro and in vivo exposure of chronic myeloid leukemia (CML) cells to IFN was evaluated and correlated with the response to in vivo treatment with IFN.
CML patients in different phases of the disease were studied. The pattern of expression of two IFN-inducible proteins involved in IFN-mediated biological activities, the p91 and p84 proteins (STAT1alpha and STAT1beta), components of the IFN-stimulated gene factor 3 (ISGF3) complex and the enzyme 2'-5' oligoadenylate synthetase (2'-5' OASE) were investigated by Western blot in peripheral blood mononuclear cells stimulated or not in vitro by IFN.
In 6/9 patients evaluated before starting treatment, STAT1 was expressed either constitutively or after in vitro stimulation by IFN. In three cases, STAT1 remained negative even after in vitro activation. The pattern of protein expression correlated with the subsequent hematological response to prolonged in vivo IFN administration: the presence of STAT1 being associated with the clinical response to IFN and the absence and non-inducibility of STAT1 with resistance to IFN. This was further substantiated by studies carried out in ten patients analyzed at the time of a documented clinico-hematological response or resistance to the in vivo administration of IFN. Finally, in order to establish whether the pattern of response to IFN treatment could be predicted at diagnosis, cells cyropreserved at diagnosis from patients with a documented complete response, confirmed also by cytogenetic negativity, or resistance, were studied. While complete responders proved STAT1 positive, none of the four resistant cases ever expressed STAT1. The expression of 2'-5' OASE did not correlate with the clinical response to IFN. This study documents the pivotal role of STAT1 in the in vitro and in vivo responses of CML cells to IFN. The constitutive or induced presence or absence of STAT1 shows a predictive correlation with the response or resistance to treatment with IFN and could be utilized to identify, at diagnosis, resistant patients who may be spared an expensive and unnecessary prolonged IFN administration.
α干扰素（IFN）在不同肿瘤的治疗中发挥作用，尤其是血液系统来源的肿瘤。IFN的作用机制仍未完全清楚，个体反应也难以预测。在本研究中，评估了慢性髓性白血病（CML）细胞在体外和体内暴露于IFN后细胞内基因表达模式，并将其与IFN体内治疗反应相关联。
研究了处于疾病不同阶段的CML患者。通过蛋白质印迹法，在体外经IFN刺激或未刺激的外周血单个核细胞中，研究了参与IFN介导的生物学活性的两种IFN诱导蛋白（p91和p84蛋白，即STAT1α和STAT1β）、IFN刺激基因因子3（ISGF3）复合物的组成成分以及2'-5'寡腺苷酸合成酶（2'-5' OASE）的表达模式。
在开始治疗前评估的9例患者中，6例患者的STAT1呈组成性表达或在体外经IFN刺激后表达。3例患者即使在体外激活后STAT1仍为阴性。蛋白质表达模式与随后长期IFN体内给药的血液学反应相关：STAT1的存在与对IFN的临床反应相关，而STAT1的缺失和不可诱导性与对IFN的耐药相关。在10例患者中进行的研究进一步证实了这一点，这些患者在记录到临床血液学反应或对IFN体内给药耐药时进行了分析。最后，为了确定在诊断时是否可以预测IFN治疗反应模式，研究了诊断时冷冻保存的细胞，这些患者有记录的完全缓解（细胞遗传学阴性也证实）或耐药。完全缓解者STAT1呈阳性，4例耐药患者均未表达STAT1。2'-5' OASE的表达与对IFN的临床反应无关。本研究证明了STAT1在CML细胞对IFN的体外和体内反应中的关键作用。STAT1的组成性或诱导性存在或缺失与对IFN治疗的反应或耐药呈预测性相关，可用于在诊断时识别可能避免昂贵且不必要的长期IFN给药的耐药患者。
