Ruxolitinib induces apoptosis of human colorectal cancer cells by downregulating the JAK1/2-STAT1-Mcl-1 axis

Under pathological conditions, the Janus kinase (JAK)/STAT signaling pathway can regulate the proliferation, differentiation and migration of tumor cells, including colorectal cancer (CRC). CRC is the third major types of cancer among males and the second among females worldwide. In China, CRC is the fifth common cancer among both males and females. Western blotting, flow cytometry, RNA interference, immunoprecipitation, xenografts models, and immunohistochemical staining were carried out to evaluate the possible mechanisms of acton of ruxolitinib. The present data suggested that ruxolitinib can suppress CRC cell proliferation by inducing apoptosis. Firstly, JAK1/2-STAT1 was identified as the target of ruxolitinib. Then, ruxolitinib downregulated myeloid cell leukemia-1 (Mcl-1) mRNA level and decreased its protein level, which enabled Bak to trigger CRC apoptosis. Furthermore, ruxolitinib exerted potent activity against CRC xenograft growth in vivo. High expression of phosphorylated STAT1 (S727) was also confirmed in 44 pairs of human colon carcinoma and adjacent normal tissues. Taken together, the results showed that ruxolitinib decreased JAK1/2-STAT1-Mcl-1 protein level and effectively suppressed CRC cell proliferation in vitro and in vivo. Therefore, ruxolitinib could be a promising anticancer agent for CRC treatment.     

Suppression of multiple anti‐apoptotic BCL2 family proteins recapitulates the effects of JAK2 inhibitors in JAK2V617F driven myeloproliferative neoplasms

Several lines of research suggest that Bcl‐xL‐mediated anti‐apoptotic effects may contribute to the pathogenesis of myeloproliferative neoplasms driven by JAK2V617F and serve as therapeutic target. Here, we used a knock‐in JAK2V617F mouse model and confirmed that Bcl‐xL was overexpressed in erythroid progenitors. The myeloproliferative neoplasm (MPN)‐induced phenotype in the peripheral blood by conditional knock‐in of JAK2V617F was abrogated by conditional knockout of Bcl2l1, which presented anemia and thrombocytopenia independently of JAK2 mutation status. Mx1‐Cre Jak2V617^W/VF/Bcl2l1^f/f mice presented persistent splenomegaly as a result of extramedullary hematopoiesis and pro‐apoptotic stimuli in terminally differentiated erythroid progenitors. The pan‐BH3 mimetic inhibitor obatoclax showed superior cytotoxicity in JAK2V617F cell models, and reduced clonogenic capacity in ex vivo assay using Vav‐Cre Jak2V617F bone marrow cells. Both ruxolitinib and obatoclax significantly reduced spleen weights in a murine Jak2V617F MPN model but did not show additive effect. The tumor burden reduction was observed with either ruxolitinib or obatoclax in terminal differentiation stage neoplastic cells but not in myeloid‐erythroid precursors. Therefore, disrupting the BCL2 balance is not sufficient to treat MPN at the stem cell level, but it is certainly an additional option for controlling the critical myeloid expansion of the disease.     

费城染色体阴性骨髓增殖性肿瘤的诊断与治疗:JAK2 V617F基因突变评价

简要回顾了近百余年人们对骨髓增殖性肿瘤(MPN)的认识过程,重点讨论这一类疾病的诊断与治疗.JAK2 V617F基因突变的发现将费城染色体阴性(Ph-)MPN带入分子生物学时代,为临床提供了重要的诊断手段和依据,指导、研发了芦可替尼(ruxolitinib)等一批靶向药物.但是,与慢性粒细胞白血病(CML)中的bcr-abl不同,JAK2 V617F突变不是MPN诊断的“金标准”,其他辅助检查和鉴别诊断仍不可少.目前,JAK抑制剂开始用于Ph-MPN患者,有一定的适应证,远期疗效正在观察,目前还不能替代有效的常规治疗,如羟基脲、阿司匹林等.     

Atypical chronic myeloid leukemia as defined in the WHO classification is a JAK2 V617F negative neoplasm

Atypical chronic myeloid leukemia (aCML) as defined by the WHO classification is a rare hematopoietic stem cell disorder, which shows both myeloproliferative as well as myelodysplastic features. Because of the presence of neutrophilic leukocytosis, aCML may resemble chronic myelogenous leukemia. However, in contrast with the latter, aCML lacks a Philadelphia chromosome or the BCR/ABL fusion gene. The molecular pathogenesis of aCML and its relationship to other myeloproliferative neoplasms is unknown. To clarify these points, the presence of JAK2 V617F was examined by a retrospective analysis of archival specimens obtained from two large medical institutions.Paraffin-embedded bone marrow (BM) trephines and clot sections were examined by an allele-specific TaqMan PCR suitable for use with decalcified tissue. Fifty-nine cases of Philadelphia (Ph) chromosome negative chronic myeloproliferative neoplasms (CMPN) and normal bone marrows (BM) served as controls. None of the nine amplifiable cases of aCML and none of the normal BM controls showed a JAK2 V617F mutation, in contrast to 45/59 (76%) of the Ph chromosome negative CMPN cases. Atypical CML should therefore be considered as a JAK2 negative chronic myeloid neoplasm that remains properly categorized, alongside chronic myelomonocytic leukemia and juvenile myelomonocytic leukemia, within the WHO group of myelodysplastic/myeloproliferative neoplasms.     

亚砷酸对JAK2V617F阳性的骨髓增殖性肿瘤的影响

目的:探讨亚砷酸(arsenic trioxide,ATO)在治疗JAK2V617F突变阳性的骨髓增殖性疾病(myelopro-liferative neoplasm,MPN)中的作用。方法:选取20例JAK2V617F阳性的MPN患者用亚砷酸治疗,观察其治疗前后不同时期相应的血象变化以及JAK2V617F表达,并与单用羟基脲的对照组作比较。结果:与对照组相比,3个月及1年后,应用亚砷酸治疗组的红细胞、血红蛋白、血小板、白细胞均明显降低(P<0.01);治疗3年后两组上述指标无明显差异(P>0.05);JAK2V617F的转阴率两组无明显差异性(P>0.05)。结论:亚砷酸作为一种诱导凋亡剂短期内可以有效地降低三系血细胞,但未有证据表明能降低MPN患者JAK2V617F的阳性表达,故长期疗效需更多的临床及实验观察。     

A sensitive and reliable semi-quantitative real-time PCR assay to detect JAK2 V617F in blood

Diagnosis of the myeloproliferative disorders, polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) is difficult due to lack of diagnostic markers. Recently, the acquisition of a mutation in the Janus kinase 2 (JAK2) gene by hemopoietic cells has been described as a genetic defect underlying myeloproliferative disorders. The mutation leads to constitutive activation of JAK2, a tyrosine kinase involved in cytokine receptor signalling. Because of the clinical importance of this mutation (JAK2 V617F) in diagnosing myeloproliferative disorders and its relevance for disease progression, we developed a semi-quantitative real-time PCR test to detect JAK2 V617F. With this assay, quantities down to 0.8% JAK2 V617F amongst wild-type DNA could reliably be detected. For quantification purposes, low intra- and inter-assay variabilities ensure good reproducibility of the assay. Thus the JAK2 V617F qPCR assay described here is quick, robust, simple and more sensitive than direct sequencing, RFLP, ARMS assay and other methods published so far to detect JAK2 V617F. We therefore believe that the assay will contribute to early diagnosis of myeloproliferative disorders and to disease management, especially when JAK2-specific inhibitors have become available for therapeutic use.     

Relationship of JAK2 (V617F) Allelic Burden with Clinico- Haematological Manifestations of Philadelphia-Negative Myeloproliferative Neoplasms

JAK2 (V617F) allelic burden is the main genetic driver behind and a potential differentiator between individual myeloproliferative neoplasm (MPN) subtypes. This study aimed to explore the relationship between JAK2 (V617F) allelic burden, MPN subtypes and their clinico-haematological manifestations in a Singapore-based cohort. Analysis was performed on a retrospectively collected dataset of 128 patients diagnosed with JAK2 (V617F) positive Philadelphia-negative MPNs between 2016 to 2017 in Singapore. Genomic analysis was conducted on blood samples via DNA extraction and Droplet Digital Polymerase Chain Reaction (ddPCR). The mean age was 62.4 (SD=14.1). 85 out of the 128 (66.4%) patients were male. There was a statistically significant difference in allelic burdens between the different MPN disease subtypes χ2(3) = 9.064, p=0.028, with essential thrombocytosis (ET) patients having the lowest mean JAK2 percentage allelic burden (26.5%). Patients with an allelic burden >50% had higher leukocyte counts (MWU 1016.5, p=0.001), haemoglobin levels (MWU 1287.0, p=0.045), lactate dehydrogenase levels (MWU 611.5, p=0.001), and lower platelet levels (MWU 1164.0, p=0.008). Subgroup analysis revealed none of these correlations was significant in the ET subgroup. The results are largely in concordance with previous research in Asian cohorts demonstrating the association between allelic burden and clinico-haematological manifestations of MPN. However, in the ET subgroup, the JAK2 (V617F) allelic burden do not correlate positively for haematological parameters which is only seen in Asian patients.     

JAK2 V617F基因突变与血管栓塞性疾病的相关性研究

目的 探讨JAK2 V617F基因突变与血管栓塞性疾病的相关性,为临床诊治和预防栓塞提供依据.方法 以首都医科大学宣武医院神经内科、心脏科及血管外科收治的血红蛋白＞ 160g/L、血小板计数＞ 300×109/L的56例患者为研究对象,其中骨髓增殖性肿瘤患者47例.回顾性分析患者血管栓塞情况、JAK2 V617F突变情况及两者之间的相关性.结果 JAK2 V617F基因突变阳性率为37.50％(21/56),血管栓塞发生率为41.07％(23/56),两者之间存在关联性(P=0.014).结论 JAK2 V617F基因突变检测有助于骨髓增殖性肿瘤患者的早期诊断和治疗,减少栓塞并发症,提高患者生命质量.     

JAK2 V617F基因突变阳性骨髓增殖性肿瘤治疗研究进展

JAK2 V617F基因突变阳性骨髓增殖性肿瘤(MPN)由真性红细胞增多症(PV)、原发性血小板增多症(ET)和原发性骨髓纤维化(PMF)组成.文章聚焦于其危险度积分系统和治疗进展,包括一线及二线治疗、JAK2抑制剂、降细胞治疗、抗纤维化和其他单药或联合治疗.     

MMP2 Gene-735 C/T and MMP9 gene -1562 C/T Polymorphisms in JAK2V617F Positive Myeloproliferative Disorders

Background: Myeloproliferative disorders (MPDs) are clonal hematologic malignancies originating at thelevel of the pluripotent hematopoietic stem cell. Matrix metalloproteases (MMPs) are proteolytic enzymes thatcontribute to all stages of malignancy progression. Genetic variants in the MMP genes may influence the biologicalfunction of these enzymes and change their role in carcinogenesis and progression. To our knowledge, this isthe first investigation of associations between the -735 C/T and -1562 C/T polymorphisms in the MMP2 andMMP9 genes, respectively, and the risk of essential thrombocytosis (ET), and polycythemia vera (PV). Materialsand Methods: The case-control study included JAK2V617F mutation positive 102 ET and PV patients and 111controls. Polymorphisms were determined by using polymerase chain reaction-restriction fragment lengthpolymorphism (PCR-RFLP) and electrophoresis. Results: No statistically significant differences were detectedbetween patient (ET+PV) and control groups regarding genotype distribution for MMP2 gene-735 C/T andMMP9 gene -1562 C/T polymorphisms and C/T allele frequency (p>0.050). Statistically borderline significancewas observed between PV and control groups regarding genotype distribution for the MMP9 gene -1562 C/Tpolymorphism (p=0.050, OR=2.26, 95%Cl=0.99-5.16). Conclusions: Consequently this study supported that CCgenotype of MMP9 gene -1562 C/T polymorphism may be related with PV even if with borderline significance.     

JAK2 V617F mutation is uncommon in non-Hodgkin lymphomas

Recently, the JAK2 V617F mutation has been reported in high proportions of chronic myeloproliferative disorders, including polycythemia vera. To see whether the JAK2 V617F is important in the pathogenesis of lymphoid malignancies, this study analysed the occurrence of the JAK2 V617F mutation in 117 non-Hodgkin lymphomas (NHLs) by a single strand conformation polymorphism assay. However, there was no JAK2 V617F mutation in the NHLs and the data suggest that the JAK2 V617F mutation may not play a role in the development of NHL.     

干扰素对JAK2 V617F阳性骨髓增殖性肿瘤PD-1/PD-L1及Treg表达的影响

 目的 探讨干扰素-alpha-2b（IFN-α2b）对JAK2 V617F阳性骨髓增殖性肿瘤（MPN）患者中程序性死亡受体-1（PD-1）、程序性死亡配体-1 （PD-L1）及CD4+ CD25+ Foxp3+调节性T细胞（Treg）表达的影响及临床意义。方法 收集JAK2 V617F阳性MPN患者61例，包括初治组41例、IFN-α2b治疗组20例，健康对照组20例。应用荧光定量PCR检测JAK2 V617F/JAK2突变率，流式细胞术检测PD-1、PD-L1、Treg的表达情况。选取15例患者骨髓及外周血标本进行体外细胞培养，应用1×106 U/L IFN-α2b作用48 h后检测PD-1、PD-L1及Treg表达情况。结果 初治组的JAK2 V617F、PD-1、PD-L1及Treg表达明显高于IFN-α2b治疗组及对照组（均P<0.05）。JAK2 V617F突变量≥50%患者骨髓髓系细胞PD-1、PD-L1及外周血Treg细胞均明显高于突变量<50%患者（均P<0.05）。相关性分析结果显示JAK2 V617F突变量与骨髓髓系细胞PD-1、PD-L1和淋巴细胞PD-1呈正相关，与Treg表达无相关性。1×106 U/L IFN-α2b作用48 h后能够体外抑制MPN原代细胞PD-1、PD-L1及Treg的表达（P<0.05）。结论 PD-1、PD-L1及Treg共同参与了MPN的发病过程，干扰素能够不同程度抑制MPNJAK2 V617F、PD-1、PD-L1及Treg表达，进而抑制MPN的进展。     

骨髓增殖性肿瘤120例JAK2 V617F基因突变的临床分析

目的 探讨JAK2 V617F基因突变在骨髓增殖性肿瘤(MPN)患者中的发生率及临床意义.方法 采用骨髓细胞学和活组织检查方法分析120例患者的骨髓病理状况,监测费城染色体(Ph染色体)和bcr-abl融合基因.从患者骨髓抽提DNA,采用荧光定量PCR技术检测JAK2 V617F基因突变.结果 所有患者均呈现出MPN各自类型的典型特征.Ph染色体和bcr-abl融合基因检测均为阴性.120例MPN患者中JAK2 V617F基因突变的阳性率为66.7％(80/120),其中真性红细胞增多症(PV)为72.7％(16/22),原发性血小板增多症(ET)为66.0％(62/94),4例原发性骨髓纤维化(PMF)患者中2例阳性.JAK2 V617F突变阳性PV患者的外周血白细胞计数(P=0.001)和血小板计数(P=0.010)均高于阴性患者;JAK2 V617F突变阳性ET患者的白细胞计数高于阴性患者(P=0.006);PMF中JAK2V617F突变阳性和阴性患者间各项指标差异均无统计学意义(均P＞0.05).结论 JAK2 V617F基因突变检测有助于bcr-abl阴性MPN的诊断和鉴别诊断,使患者能够在早期被发现和治疗.     

JAK2基因突变与骨髓增生性疾病的关系

 骨髓增生性疾病（MPD）中真性红细胞增多症（PV）、特发性血小板增多症（ET）、特发性骨髓纤维化（IMF）发现蛋白酪氨酸激酶（JAK2）基因上有一个碱基突变JAK2 V617F,突变明显与PV、ET和IMF的发生有关,这一发现可能成为诊断这类综合征的一种方式,也为寻找新的药物治疗MPD提供了明确的作用目标,同时还为研究细胞生长紊乱和细胞功能紊乱提供新的研究思路。