LKB1、VEGFR2在非小细胞肺癌组织中表达及临床意义的研究

目的探究人Liver kinase B1(LKB1)与血管内皮生长因子受体-2(VEGFR2)在非小细胞肺癌组织中的表达情况,并探究其临床意义。方法采用免疫组化方法测定65例非小细胞肺癌组织及40例癌旁组织LKB1、VEGFR2表达情况。分析LKB1、VEGFR2表达情况与临床病理特征的相关性。结果肺癌组织中LKB1阳性率低于癌旁组织,VEGFR2阳性率高于癌旁组织。LKB1在腺癌中的表达阳性率高于鳞癌,VEGFR2在腺癌中的表达阳性率低于鳞癌。在具有吸烟史、淋巴转移、临床低分期以及低分化程度中LKB1阳性率更低,VEGFR2阳性率更高,差异均有统计学意义(均P0.05)。结论腺癌组织中LKB1表达水平高于鳞癌组织;非小细胞肺癌组织中LKB1、VEGFR2呈现相反的表达趋势。LKB1低表达与VEGFR2高表达提示肺癌患者具有吸烟史、出现淋巴转移、高临床分期以及低分化程度。     

LKB1调节细胞周期的主要分子机制

LKB1基因编码丝氨酸/苏氨酸蛋白激酶,该基因突变导致黑斑息肉综合征。在非小细胞肺癌中LKB1基因突变率可高达30％。作为抑癌基因,LKB1可以引起细胞周期阻滞在G1期,抑制细胞生长。LKB1主要以p53依赖的机制上调p21表达来对细胞周期进行调控。定位在细胞质中的LKB1可以引起细胞生长负调控的信号传递,而定位在细胞...     

LKB1 expression and the prognosis of lung cancer: A meta-analysis

Background:In the past few decades, many lines of evidence implicate the importance of liver kinase B1 (LKB1) as a tumor suppressor gene in the development and progression of solid tumours. However, the prognostic and clinicopathological value of LKB1 in patients with lung cancer are controversial. This article aimed to investigate the latest evidence on this question.Methods:A systematic literature searched in the PubMed, Web of Science, Embase, Cochrane library, Scopus until September 20, 2020. The association between overall survival (OS), relapse-free survival (RFS), progression-free survival (PFS), clinicopathological features and LKB1 were analysed by meta-analysis.Results:Eleven studies including 1507 patients were included in this meta-analysis. The pooled results revealed that low LKB1 expression was significantly associated with poor overall survival (OS) (HR = 1.67, 95% CI: 1.07–2.60, P = .024) in lung cancer. However, no association was found between LKB1 expression and DFS/PFS (HR = 1.29, 95% CI: 0.70–2.39, P = .410). Pooled results showed that low LKB1 expression was associated with histological differentiation (poor vs moderate or well, OR = 4.135, 95% CI:2.524–6.774, P < .001), nodal metastasis (absent vs present, OR = 0.503, 95% CI: 0.303–0.835, P = .008) and smoking (yes vs no, OR = 1.765, 95% CI: 1.120–2.782, P = .014).Conclusion:These results suggest that low expression of LKB1 can be considered as a unfavorable prognostic biomarker for human lung cancer, which should be further researched.     

LKB1和VEGFR2评价肺腺癌预后的意义

目的探讨LKB1、VEGFR2在肺腺癌中的表达情况,分析其预后意义。方法应用免疫组化方法检测46例肺腺癌中LKB1、VEGFR2的表达情况。结果 LKB1在癌旁正常肺组织、淋巴结转移阴性组肺腺癌、Ⅰ～Ⅱ期肺腺癌中的表达阳性率明显高于肺腺癌组织、淋巴结转移阳性组肺腺癌和ⅢA期肺腺癌(82.61%vs 63.04%、75.00%vs 44.44%、75.00%vs35.71%),差异有统计学意义(P<0.05)。VEGFR2在癌旁正常肺组织、淋巴结转移阴性组肺腺癌、Ⅰ～Ⅱ期肺腺癌中的表达阳性率则明显低于肺腺癌组织、淋巴结转移阳性组肺腺癌和ⅢA期肺腺癌(34.78%vs 58.70%、46.43%vs 77.78%、46.88%vs85.71%),差异有统计学意义(P<0.05)。结论 LKB1、VEGFR2在肺腺癌中的表达情况可能与肺腺癌患者的预后有关,LKB1低表达、VEGFR2高表达可能提示预后不良。     

Molecular detection of t(8;21)/AML1-ETO in AML M1/M2: correlation with cytogenetics,morphology and immunophenotype

The t(8;21) identifies a subgroup of acute myeloid leukaemia (AML) with a relatively good prognosis which may merit different treatment. It is associated predominantly, but not exclusively, with AML M2, and corresponds to rearrangements involving the AML1 and ETO genes. AML1-ETO positive, t(8;21) negative cases are well recognized but their incidence is unknown. In order to determine optimal prospective AML1-ETO RT-PCR screening strategies, we analysed 64 unselected AML M1 and M2 cases and correlated the results with other biological parameters. Molecular screening increased the overall detection rate from 8% to 14%. AML1-ETO was found in 3% (1/32) of AML M1 and 25% (8/32) of M2, including three patients without a classic t(8;21) but with chromosome 8 abnormalities. It was more common in younger patients. Correlation with morphology enabled development of a scoring system which detected all nine AML1-ETO-positive cases with a false positive rate of 7% (4/55). Although certain AML1-ETO-positive cases demonstrated characteristic immunological features (CD19 and CD34 expression, CD33 negativity), each of these markers was insufficiently specific to permit prediction in an individual case. We conclude that initial routine prospective molecular screening for AML1-ETO in all AMLs, combined with standardized morphological and immunological analysis, is desirable in order to produce improved prognostic stratification and to determine whether screening can ultimately be restricted to appropriate subgroups.     

Molecular detection of t(8;21)/AML1-ETO in AML M1/M2: correlation with cytogenetics, morphology and immunophenotype

The t(8;21) identifies a subgroup of acute myeloid leukaemia (AML) with a relatively good prognosis which may merit different treatment. It is associated predominantly, but not exclusively, with AML M2, and corresponds to rearrangements involving the AML1 and ETO genes. AML1-ETO positive, t(8;21) negative cases are well recognized but their incidence is unknown. In order to determine optimal prospective AML1-ETO RT-PCR screening strategies, we analysed 64 unselected AML M1 and M2 cases and correlated the results with other biological parameters. Molecular screening increased the overall detection rate from 8% to 14%. AML1-ETO was found in 3% (1/32) of AML M1 and 25% (8/32) of M2, including three patients without a classic t(8;21) but with chromosome 8 abnormalities. It was more common in younger patients. Correlation with morphology enabled development of a scoring system which detected all nine AML1-ETO-positive cases with a false positive rate of 7% (4/55). Although certain AML1-ETO-positive cases demonstrated characteristic immunological features (CD19 and CD34 expression, CD33 negativity), each of these markers was insufficiently specific to permit prediction in an individual case. We conclude that initial routine prospective molecular screening for AML1-ETO in all AMLs, combined with standardized morphological and immunological analysis, is desirable in order to produce improved prognostic stratification and to determine whether screening can ultimately be restricted to appropriate subgroups.     

LKB1 Positively Regulates Dendritic Cell-induced T Cell Immunity and Suppresses Tumor Development

Background: The functions of dendritic cells (DCs) are influenced by their intracellular metabolism, in which liver kinase B1 (LKB1) plays an important role. However, due to the difficulty in isolating the DCs, the roles of LKB1 in DC maturation and functions in tumor settings have been poorly characterized.Objective: To investigate the roles of LKB1 in DC functions including phagocytosis and presentation of antigens, activation, T cell differentiation, and ultimately tumor eradication.Methods: Genetic modification of Lkb1 in the DCs was made by lentiviral transduction, and their impacts on T cell proliferation, differentiation, activity, or B16 melanoma metastasis were examined by flow cytometry, qPCR, or lung tumor nodule counting.Results: LKB1 did not affect antigen uptake and presentation by the DCs, but facilitated the stimulation of T cell proliferation. Interestingly, following T cell activation, Foxp3-expressing regulatory T cells (Treg) were increased (P=0.0267) or decreased (P=0.0195) in mice injected with Lkb1 knockdown DCs or overexpressing DCs, respectively. Further exploration revealed that LKB1 inhibited OX40L (P=0.0385) and CD86 (P=0.0111) expression, and these co-stimulatory molecules enhanced Treg proliferation, and downregulated immune suppressive cytokine IL-10 (P=0.0315). Moreover, we found that the injection of the DCs with limited LKB1 expression before tumor inoculation could reduce their production of granzyme B (P<0.0001) and perforin (P=0.0042) from CD8+T cells, thereby impairing their cytotoxicity and promoting tumor growth.Conclusion: Our data suggest that LKB1 can enhance DC-mediated T cell immunity by restraining Treg development and thereby suppressing tumor growth.     

LKB1和血管内皮生长因子在胃癌组织中的表达及其临床意义

目的探讨LKB1和血管内皮生长因子(VEGF)在胃癌中的表达及临床意义。方法采用免疫组织化学(SP)法检测115例胃癌组织和20例胃正常组织中LKB1和VEGF的表达,并探讨其与胃癌分期、淋巴结转移、Lauren's分型及预后的关系。结果 LKB1在胃癌组织中的阳性率为20.9%,低于正常胃组织中的95.0%(P0.01);VEGF在胃癌组织中的阳性率为64.3%,高于正常胃组织中的5.0%(P0.01)。LKB1在胃癌组织中的低表达与胃癌的TNM分期、淋巴结转移、Lauren's分型及预后有关(P0.05);VEGF在胃癌中的表达与淋巴结转移、远处转移、TNM分期及预后相关(P0.05)。结论 LKB1的低表达与胃癌的发生、发展有关,对胃癌恶性生物学行为的评估及预后判断具有重要的指导意义。     

LKB1和VEGFR_2在不同分期非小细胞肺癌中的表达

目的检测LKB1、VEGFR2在不同TNM分期非小细胞肺癌(NSCLC)中的表达情况。方法选取88例经手术治疗的不同TNM分期的非小细胞肺癌患者,切取癌组织及癌周5 cm以上无转移的正常肺组织,应用免疫组化方法测定LKB1和VEGFR2的表达情况。结果 LKB1和VEGFR2在肺癌组织及正常肺组织中均有表达。LKB1蛋白表达率在正常肺组织中明显高于癌组织(P0.01),VEGFR2在癌组织的表达率显著高于正常肺组织(P0.01);LKB1和VEGFR2在不同分期肺癌组织中的表达有显著差异(P0.05)。结论 LKB1和VEGFR2在非小细胞肺癌中的表达情况可能帮助判断非小细胞肺癌的分期及预后。     

AML1-EVI1转基因斑马鱼模型的建立及对造血转录因子的调控

目的:通过建立表达急性髓系白血病(AML)1-同向性病毒整合位点(EVI)1融合基因斑马鱼模型,研究AML1-EVI1融合基因对造血转录因子的影响。方法:构建携带绿色荧光蛋白的AML1-EVI1质粒,显微注射到斑马鱼胚胎单细胞期,建立生殖系稳定转染的转基因模型,常规养殖到F2代。以F2代转基因斑马鱼作为实验对象,运用反转录(RT)-PCR验证AML1-EVI1融合基因的表达,外周血涂片、肾细胞涂片检测血细胞形态学改变,全胚胎原位杂交及荧光实时定量PCR(RFQ-PCR)检测融合基因对造血转录因子[GATA结合蛋白1(GATA1)、髓过氧化物酶(MPO)]的影响。结果:在性成熟146条嵌合表达的F0代斑马鱼中鉴定得到3条(2.1%)转基因阳性斑马鱼,其中雄鱼2条,雌鱼1条。外周血涂片及肾细胞涂片显示转基因斑马鱼出现造血细胞分化障碍,幼稚细胞增多,全胚胎原位杂交及RFQ-PCR均显示,与野生型相比,转基因型斑马鱼造血转录因子MPO基因表达量无论造血细胞发育早期还是晚期都明显下降,转录因子GATA1则在发育早期上调,晚期呈现明显下调。结论:AML1-EVI1融合基因通过调节转录因子抑制髓系分化,红系发育,促进原始细胞增殖。     

Point Mutations of the RUNX1/AML1 Gene in Sporadic and Familial Myeloid Leukemias

The RUNX1/AML1 gene is known to be the most frequent target for chromosomal translocation in leukemia. In addition, recent studies have demonstrated point mutations in the RUNX1 gene as an another mode of genetic lesion resulting in leukemia. Of particular interest, sporadic point mutations of biallelic type are found in a tight association with either the acute myelogenous leukemia (AML) MO subtype or trisomy 21. Germline mutations give rise to a familial platelet disorder that results in a predisposition to acute myelogenous leukemia (FPD/AML). Most of the RUNX1 mutants were defective in DNA binding but still active in beta binding, a characteristic that is consistent with the 3-dimensional structural findings and may explain the dominant inhibitory effects. Although genuine haploinsufficiency of RUNX1 was observed in some cases, a greater majority of mutant RUNX1 proteins may also act in a dominant-negative manner, possibly creating a higher propensity for leukemia development. The stronger dominant-negative effect was also deduced to be the major mechanism of the chimeric genes created by chromosomal translocations. The decrement of RUNXI activity may be a common underlying cause for RUNX1-related leukemias. However, because these RUNX1 abnormalities per se are insufficient for leukemogenesis, cooperating genetic alteration(s) should be intensively sought for further mechanistic insights and future clinical applications.     

MDR1 gene expression and drug resistance of AML cells

We investigated the cellular drug resistance to aclarubicin (Acla), cytosine arabinoside (Ara-C), daunorubicin (Dau), doxorubicin (Dox), etoposide (Etop) and mitoxantrone (Mitox) using the MTT assay at time of disease presentation in 93 cases of acute myeloid leukaemia (AML). In 31 cases we concomitantly investigated MDR1 (multiple drug resistance 1 gene) expression (semi-quantitative competitive RT-PCR) of the leukaemic cells. Drug resistance towards Dau, Dox and Etop was correlated to the MDR1 expression of the AML cells ( P  < 0.05) with high MDR1 expression being associated with high drug resistance towards these drugs. Although the data did not allow firm conclusions to be drawn on the correlation between MDR1 expression and drug resistance towards Ara-C and Mitox, the drug resistance towards Acla clearly was not correlated to, or dependent on, the MDR1 expression level of the AML blast cells. In addition, when examining the cross-activities among the six drugs distinct patterns emerged. Thus, high to very high degrees of cross-activity were found to exist between Dau, Dox, Etop and Mitox, whereas Ara-C had moderate cross-activity with the other drugs except Acla, which showed absent to moderate cross-activity with the other drugs. We conclude that MDR1 gene expression is of significance for cellular drug resistance towards specific (MDR1-related) drugs in AML, whereas it is not of significance regarding drug resistance towards other drugs, which is the case with the anthracycline Acla. We suggest that in the place of other more or less complicated ways to circumvent MDR1-mediated drug resistance, Acla may be used to replace Dau, Dox and other MDR1-related drugs if proven as potent as the drug it is to substitute.     

Haploinsufficiency of Runx1/AML1 promotes myeloid features and leukaemogenesis in BXH2 mice

Haploinsufficiency of RUNX1/AML1 is associated with familial platelet disorder with a predisposition to acute myeloid leukaemia (FPD/AML), but the causal relationship remains to be addressed experimentally. Mice heterozygous for the Runx1 null mutation, Runx1+/-, are considered to be genetically comparable with human FPD/AML patients but do not develop spontaneous leukaemia. To induce additional genetic alterations, retroviral insertional mutagenesis was employed with the use of BXH2 mice, which develop myeloid leukaemia because of the random integration of retrovirus present in the mouse. Heterozygous disruption of Runx1 in BXH2 mice resulted in a shortening of the latency period of leukaemia. In addition, BXH2-Runx1+/- mice exhibited more marked myeloid features than control mice. Moreover, the c-Kit gene, mutated in human RUNX leukaemias, was recurrently activated in BXH2-Runx1+/- mice, and a colony-forming assay revealed synergism between the Runx1+/- status and c-KIT overexpression. In conclusion, the BXH2-Runx1+/- system is a promising mouse model to investigate the mechanism of leukaemogenesis in FPD/AML.     

Low-dose cytosine-arabinoside in the treatment of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)

Summary Ten AML- and two MDS-patients in whom conventional chemotherapy was contraindicated or ineffective were treated with low dose ARA-C, 10 mg/m² per 12^hs.c. for 2–4 weeks. Seven patients obtained a complete and two a partial remission. Our findings suggest that low dose ARA-C may act both by induction of differentiation and/or inhibition of proliferation.Supported by the Hamburger Krebsgesellschaft