小鼠3LL肿瘤局部高表达GM-CSF增强抗肿瘤免疫的实验研究

背景与目的:粒-单核细胞集落刺激因子(grannulocyte/monocyte-colony stimulating factor,GM-CSF)具有促进未成熟树突状细胞(dendritic cell,DC)成熟、上调其MHC分子和协同刺激分子表达以及增强DC对肿瘤抗原的提呈等作用.本文研究GM-CSF在肿瘤局部的高表达可以促进肿瘤局部DC成熟及亚群改变,从而诱导增强的抗肿瘤免疫效应.方法:以GM-CSF转染小鼠Lewis肺癌细胞株3LL获得3LL-GM,分别以3LL、3LL-vec(空载体对照)和3LL-GM细胞接种C57BL/6小鼠,分离肿瘤局部免疫细胞,流式细胞术检测DC成熟度、DC亚群比例、CD8 效应T细胞的活化及其功能.结果:3LL-GM肿瘤局部GM-CSF浓度高达441.22 ng/g肿瘤组织,显著高于母本3LL组的0.53 ng/g肿瘤组织(P<0.05)和空载体对照3LL-vec组的0.42 ng/g肿瘤组织(P<0.05).在3LL-GM、3LL和3LL-vec组小鼠肿瘤内浸润的CD11c DC细胞中,I-Ab 细胞的比例分别为60.62%、19.98%和23.12%(P<0.05),CD80 细胞的比例分别为60.93%、37.43%和47.03%(P<0.05),表明肿瘤局部GM-CSF促进DC成熟;同时,三组小鼠肿瘤内浸润的CD11c CD8α CD4-DC亚群比例分别为60.82%、40.00%和29.27%(P<0.05),显示肿瘤局部GM-CSF促使DC分化为CD11c CD8α CD4-亚群.3LL-GM组小鼠肿瘤内浸润淋巴细胞(tumor infiltrating lymphocyte,TIL)中,CD3 CD62Llow细胞比例高达20.84%,显著高于3LL组的6.34%(P<0.05)和3LL-vec组的15.18%(P<0.05);并且分泌IFN-γ的CD8 T淋巴细胞比例为2.77%,与对照组相比差异具有显著性(P<0.05).结论:肿瘤局部高表达GM-CSF,可通过提高DC成熟度及上调CD11c CD8α CD4-DC亚群在肿瘤局部的比例,诱导增强的抗肿瘤免疫效应,最终导致肿瘤消退.     

趋化因子SLC和免疫佐剂CpG-ODN联合应用对小鼠移植黑素瘤的疗效

目的：探讨次级淋巴组织趋化因子（seccondary lymphoid tissue chemokine, SLC）和CpG寡聚脱氧核苷酸（CpG oligodeoxynucleotide, CpGODN）联合应用对小鼠移植黑素瘤的治疗效果及其可能机制。方法：制备SLCFc融合蛋白,体外检测SLCFc对小鼠淋巴细胞的趋化效应。建立小鼠黑素瘤移植模型,随机分生理盐水对照组、CpGODN组、SLCFc组以及SLCFc+CpGODN组共4组。观察治疗后各组小鼠肿瘤的生长情况,流式细胞术检测移植瘤组织中淋巴细胞的种类和浸润情况。结果：成功制备SLCFc蛋白,SLCFc对小鼠淋巴细胞具有剂量依赖性（0.03、0.3和3 μg/L）趋化作用。瘤内注射SLCFc和(或)CpGODN明显抑制肿瘤的生长,联合治疗组瘤体明显小于对照组（P<0.01）,并且小鼠存活时间也明显延长。联合治疗组瘤体内CD4+、CD8+T淋巴细胞和CD11c+树突状细胞较对照组显著增多（P<0.05,P<0.01）,并且其肿瘤引流淋巴结也明显增大。结论：SLC和CpGODN联合应用对小鼠移植黑素瘤有抑制作用,其机制与趋化CD4+T、CD8+T细胞和促进DCs增殖有关。     

重组溶瘤单纯疱疹病毒oHSV2 治疗结直肠癌的实验研究

  目的  评估重组溶瘤单纯疱疹病毒oHSV2在CT26结肠癌荷瘤小鼠中的抗肿瘤效果,初步探讨其治疗机制。  方法  构建CT26细胞荷瘤小鼠肿瘤模型。1）小鼠瘤内注射oHSV2,ELISA法测定血清中粒细胞-巨噬细胞集落刺激因子（granulocyte-macro-phage colony-stimulating factor,GM-CSF）浓度;2）荷瘤小鼠分为oHSV2组、5-氟尿嘧啶（5-FU）组（阳性对照组）、磷酸盐缓冲液（PBS）组（阴性对照组）。给药后,记录小鼠体质量、肿瘤体积、生存期及生活状态等变化,评估病毒抗肿瘤效果;3）流式细胞术定量检测肿瘤引流淋巴结（tumor-draining lymphnode,TDLN）内树突状细胞（dendritic cell,DC）及瘤体内CD4+T与CD8+T的比例。  结果  1）瘤内注射oHSV2后,血清中的GM-CSF浓度不断升高。首次给药后第8 天出现高峰（3150±327.1）pg/mL,后缓慢下降;2）相比PBS组,oHSV2和5-FU组均表现出显著的抗肿瘤效果,小鼠生存期显著延长（50 d vs. 36 d,P＜0.01;51 d vs. 36 d,P＜0.01）,但oHSV2治疗未引起小鼠体质量下降。治疗起始第28天,5-FU组平均体质量较PBS组有显著性差异（16.61 g vs. 22.07 g,P＜0.01）,oHSV2组与PBS组差异无统计学意义（P>0.05）,且小鼠病毒注射区皮肤无坏死、溃疡;3）流式分析结果显示相比PBS组,oHSV2治疗组的DC（6.49% vs. 3.73%,P＜0.01）,CD4+T（15% vs. 8.57%,P＜0.01）与CD8+T（8.19% vs. 5.15%,P＜0.01）比例升高。而5-FU组各细胞比例较PBS组明显降低（P＜0.05）。  结论  瘤内注射oHSV2有效抑制结直肠癌细胞生长,病毒治疗与化疗药物相比不伴有明显的毒副反应。病毒在荷瘤小鼠体内复制产生具有生物活性的GM-CSF,可增强抗肿瘤免疫。      

恶性肿瘤患者外周血CD146+T淋巴细胞的检测及其临床意义

目的 探讨CD146+T淋巴细胞在肿瘤患者外周血中的变化及其临床意义.方法 用流式细胞术检测47例健康对照组和188例肿瘤患者外周血中CD3+ CD146+T淋巴细胞的数量,并观察其在肿瘤痰病中的变化.结果 (1)与健康对照组比较,总肿瘤组、肝癌、肺癌组、食管癌、乳腺癌、胃癌、胰腺癌组的CD146+T/T比例显著升高,差异有统计学意义(P＜0.001).(2)与健康对照组比较,肿瘤组的外周血T细胞绝对数是降低的(P＜0.05),而CD146+T绝对数却是与健康对照相似(P＞0.05);(3)恶性肿瘤患者外周血CD146+T比例与T细胞绝对计数负相关(n=188,r=-0.297,P＜0.001).(4)肿瘤转移组与未转移组的CD146+T/T比例的比较未观察到差异有统计学意义(P＞005).结论 肿瘤患者外周血CD146+T比例增高,可能是机体抗肿瘤免疫调节的一个重要方面.     

CpG ODN对急性粒-单核细胞白血病荷瘤小鼠免疫治疗作用研究

目的:探讨两种CpG ODN序列对急性粒-单核细胞白血病荷瘤小鼠模型的免疫治疗作用。方法:通过注射WEHI-3细胞构建急性粒-单核细胞白血病荷瘤小鼠模型，分别皮下注射PBS无菌缓冲液、CpG 1826、CpG Seq14，观察治疗后各组小鼠的一般状况、生存时间、瘤结节生长、病理切片等，综合评价两种CpG ODN的治疗效果。结果:皮下接种1×106个WEHI-3细胞，成功建立急性粒-单核细胞白血病荷瘤小鼠模型。肿瘤组平均生存时间20.87天，CpG 1826组 32.60天，CpG Seq14组 28.35天，两种CpG治疗组小鼠平均存活时间明显较肿瘤组长，P＜0.05；实验初期，肿瘤组及两CpG治疗组小鼠较正常组小鼠体重增长明显，终末期体重明显下降；肿瘤组小鼠瘤结节较同期两CpG治疗组小鼠大，且增长速度快；肿瘤组小鼠肝脏、脾脏、肿瘤组织中均可见广泛瘤细胞浸润，CpG 治疗组肝脏、脾脏中瘤细胞浸润明显减少，脾脏白髓区明显较对照组扩大，小鼠免疫功能增强，减少了肿瘤细胞的器官浸润；两实验组小鼠注射CpG部位均未见红肿、硬结、坏死等不良反应。结论:CpG 1826、CpG Seq14直接用于急性粒-单核细胞白血病荷瘤小鼠模型的免疫治疗，均可增强小鼠抗肿瘤作用，延长生存时间，且无明显毒副作用。     

肺癌患者肿瘤浸润淋巴细胞中IL-17的分布特征及临床意义

目的:探讨肺癌患者肿瘤浸润淋巴细胞中IL-17的分布特征及其临床意义。方法:流式细胞术检测15例肺癌组织和15例配对远癌正常组织中浸润淋巴细胞的IL-17表达水平。结果:肺癌患者肿瘤组织浸润淋巴细胞中IL-17A显著高于远癌正常组织（P＜0.000 1）,肿瘤组织中浸润产生IL-17的CD3+CD4+T细胞（Th17）（P＜0.001）、CD3+CD8+T细胞（Tc17）（P＜0.001）、γδT细胞（γδT17）(P＜0.000 1)均高于远癌正常组织;肺癌患者肿瘤组织浸润Th17和Tc17水平无明显差异（P＞0.05）,而γδT17水平显著高于Th17（P＜0.001）和Tc17（P＜0.000 1）;肿瘤组织中浸润的γδT17表达水平和淋巴结转移相关（P＜0.05）。结论:IL-17和肺癌发生相关,其早期主要来源是肿瘤浸润的γδT细胞;γδT17数量与淋巴结转移有关,提示γδT17细胞可能参与肺癌病程的进展。     

CD4+T细胞与肿瘤免疫

在肿瘤免疫中细胞免疫发挥着重要作用,其中T细胞介导的特异性免疫应答反应更为重要.近年来CD4+T细胞在抗肿瘤免疫中的作用越来越受到重视.在肿瘤免疫中CD4+T细胞启动后可以通过多种机制启动细胞毒性T淋巴细胞(CTL),维持和加强CTL的抗肿瘤反应,并且可以作为效应细胞发挥抗肿瘤作用,CD4+T细胞中的一个亚群细胞CD4+ CD25+T调节细胞对肿瘤免疫有抑制作用.     

自体CIK细胞治疗对不同阶段肿瘤患者免疫功能的影响

目的 探讨自体细胞因子诱导的杀伤细胞（CIK）治疗对不同阶段的恶性肿瘤患者免疫功能的影响。方法 162例恶性肿瘤患者分为A组（肿瘤晚期临终患者,预计生存期＜3个月）、B组（存在远处转移或局部晚期肿瘤患者,预计生存期＞3个月）和C组（根治术后患者）,另选取健康志愿者作为空白对照组（D组）。检测治疗前后A、B、C 3组患者及D组免疫功能的变化,包括CD3+、CD3+CD4+、CD3+CD8+、CD3+CD56+和CD4+／CD8+T淋巴细胞亚群水平,并监测治疗相关的不良反应。结果 自体CIK细胞治疗前,A、B、C组患者CD3+、CD3+CD4+T细胞亚群水平低于D组,CD3+CD8+T淋巴细胞亚群水平高于D组,差异均有统计学意义（P＜0.05）。经过2次自体CIK细胞治疗后,A组患者CD3+T细胞水平较治疗前降低（P＜0.05）,CD3+、CD3+CD4+、CD3+CD8+、CD3+CD56+和CD4+／CD8+与D组比较差异有统计学意义（P＜0.05）;B组治疗后CD3+、CD3+CD56+T淋巴细胞水平较治疗前升高（P＜0.05）,CD3+、CD3+CD4+、CD3+CD8+与D组比较差异有统计学意义（P＜0.05）;C组治疗后CD3+、CD3+CD4+、CD3+CD56+T细胞亚群水平较治疗前升高（P＜0.05）,CD3+、CD3+CD4+、CD3+CD8+、CD3+CD56+和CD4／CD8与D组比较差异无统计学意义（P＞0.05）。各组患者因回输CIK引起的不良反应发生率较低,组间差异均无统计学意义。结论 自体CIK细胞治疗可增强细胞免疫功能,纠正恶性实体瘤患者外周血T细胞亚群紊乱状态,治疗相关的不良反应可耐受,经对症处理后均可缓解,且不良反应与肿瘤所处阶段无关。     

CD4+T细胞与肿瘤免疫

在肿瘤免疫中细胞免疫发挥着重要作用,其中T细胞介导的特异性免疫应答反应更为重要.近年来CD4+T细胞在抗肿瘤免疫中的作用越来越受到重视.在肿瘤免疫中CD4+T细胞启动后可以通过多种机制启动细胞毒性T淋巴细胞(CTL),维持和加强CTL的抗肿瘤反应,并且可以作为效应细胞发挥抗肿瘤作用,CD4+T细胞中的一个亚群细胞CD4+ CD25+T调节细胞对肿瘤免疫有抑制作用.     

125I粒子植入联合抗PD-1治疗对小鼠Lewis肺癌的抑制作用研究

  目的  研究125I粒子植入对免疫微环境的影响,以及125I粒子植入联合抗程序性死亡受体-1（programmed cell death receptor-1,PD-1）治疗的抗肿瘤疗效。  方法  在小鼠右后肢皮下注射Lewis肺癌（LLC）细胞构建肿瘤模型,利用流式细胞术分析125I粒子植入后PD-1、程序性死亡配体1（programmed death-ligand 1,PD-L1）、Treg细胞的表达。在小鼠右后肢（原位肿瘤）和左前肢（远位肿瘤）皮下注射LLC细胞,将小鼠随机分为PBS组、抗PD-1组、125I粒子植入组和联合治疗组。绘制肿瘤生长曲线,流式分析肿瘤浸润CD4+及CD8+T细胞比例。  结果  125I粒子植入12天后PD-L1及PD-1表达上调（P < 0.01）,Treg表达无显著性差异（P=0.196）。与其余各组相比,联合治疗组小鼠原位和远位肿瘤生长均受到明显抑制（均P < 0.05）,肿瘤浸润CD8+T细胞比例显著增加（均P < 0.05）。  结论  125I粒子植入联合抗PD-1治疗能激活机体抗肿瘤免疫,协同抑制小鼠LLC生长。      

DNMT3A、FLT3-ITD合并NPM1基因突变正常核型急性髓系白血病患者的临床特征及预后分析

目的 分析DNMT3A、FLT3-ITD合并NPM1基因突变的正常核型急性髓系白血病(AML)患者的临床特征,探讨该类患者的预后.方法 回顾性分析2005年12月至2014年6月就诊的109例正常核型AML患者的临床特征及预后.其中DNMT3A/FLT3-ITD/NPM1+AML患者共25例,单独FLT3-ITD+ AML患者共32例,单独NPM1+AML患者24例,单独DNMT3A+ AML患者28例.结果 25例DNMT3A/FLT3-ITD/NPM1+ AML患者平均年龄46岁,伴有高白细胞(81.7×109/L)及较高的骨髓原始细胞(66.3％).其中,17例选择大剂量化疗,8例行异基因造血干细胞移植,与DNMT3A+、FLT3-ITD+、NPM1+AML组比较,差异均无统计学意义.25例DNMT3A/FLT3-ITD/NPM1+患者的3年总生存率为17.65％,3年无病生存率为13.88％,与DNMT3A+、FLT3-ITD+、NPM1+AML组差异均有统计学意义(P值分别为0.049 9、0.036 1、0.013 4),3年无病生存率差异无统计学意义(均P＞ 0.05).结论 DNMT3A、FLT3-ITD合并NPM1基因突变的正常AML患者往往合并高的外周血白细胞及骨髓原始细胞,预后较差.     

Plasma FLT3-L levels predict bone marrow recovery from myelosuppressive therapy

BACKGROUND: During the recovery period after anticancer myelosuppressive therapy, hematopoietic progenitor cells become mitotically active in order to replenish the bone marrow compartment and remain hyperproliferative even after normalization of peripheral white blood cells and platelets. At this stage, the progenitors are more radiosensitive and chemosensitive. Dosing patients with additional cytotoxic therapy during this phase will likely result in more severe toxicity. For example, the authors have noted that the red bone marrow (RM) dose resulting from radioantibody therapy does not correlate with observed bone marrow toxicity. Several patients given similar RM doses had Grade 3 or 4 toxicity, whereas others had Grade 0-2 toxicity even though their white blood cell (WBC) and (PLT) counts were normal at the time of dosing. The goal of these studies was to establish a noninvasive predictive marker of bone marrow activity that could determine stem cell and progenitor cell recovery from previous myelosuppressive therapy. METHODS: A retrospective study was conducted to quantitate plasma levels of 5 cytokines regulating hematopoiesis, namely, 2 stimulatory fms-like tyrosine kinase (FLT3-L) and stem cell factor (SCF) and 3 inhibitory growth factors tumor necrosis factor-alpha (TNFalpha), tumor growth factor-beta, and macrophage inflammatory protein (MIP-1alpha), by immunoassay in 43 patients enrolled in clinical trials at Garden State Cancer Center in Belleville, New Jersey. All patients had had previous chemotherapy with a duration of 1-24 months. The serum cytokine values were correlated with the magnitude of leukopenia or thrombocytopenia following a single dose of radioantibody as the cytotoxic therapy. RESULTS: Plasma FLT3-L levels predicted excess platelet toxicity in 13 of 16 patients (mean = 225 +/- 106 pg/mL) and resulted in a false-positive in only 3 of 27 other patients (mean = 80 +/- 41 pg/mL). Plasma FLT3-L > 135 pg/mL resulted in 81% sensitivity and 89% and 86% specificity and accuracy, respectively, for predicting excess toxicity caused by additional cytotoxic therapy. The positive likelihood ratio was 7.5 (95% confidence interval, 2.5-22.5) and the negative likelihood ratio was 0.19 (95% confidence interval, 0.05-0.67). CONCLUSIONS: Elevated plasma FLT3-L in patients who previously received chemotherapy is a predictive measure of the stage of recovery of the bone marrow compartment. FLT3-L seems to identify the likelihood that the patient will experience Grade > or = 3 thrombocytopenia if additional cytotoxic therapy is administered. Knowledge of bone marrow activity should permit therapy that is more aggressive by establishing the earliest possible time for dosing with any cytotoxic agent for which myelosuppression is the dose-limiting toxicity.     

老年急性非早幼粒细胞白血病NPM1及FLT3-ITD基因突变特征及临床意义

目的:探讨老年急性非早幼粒细胞白血病（non-acute promyelocytic leukemia,non-APL）NPM1及FLT3-ITD基因突变特征及临床意义。方法:回顾性分析本院2011年1月至2018年6月接受NPM1、FLT3-ITD基因突变检测的98例老年non-APL患者临床资料,统计NPM1、FLT3-ITD基因突变阳性率,分析不同核型non-APL患者NPM1、FLT3-ITD基因突变情况,并比较 NPM1/FLT3-ITD基因突变阳性与阴性患者性别、年龄、白细胞、血小板、血红蛋白、骨髓原始细胞、CD34+、CD117+的关系。结果:NPM1基因突变阳性20例,占20.41%;FLT3-ITD基因突变阳性15例,占15.31%;NPM1、FLT3-ITD基因突变双阳性5例,占5.10%。正常核型38例,占38.78%,正常核型患者NPM1、FLT3-ITD基因突变阳性率及双阳性率均显著高于异常核型者（P<0.05）。NPM1基因突变阳性患者白细胞计数、血小板计数均显著大于NPM1基因突变阴性者,CD34+比例显著小于NPM1基因突变阴性者（P<0.05）;FLT3-ITD基因突变阳性患者白细胞、骨髓原始细胞均显著大于FLT3-ITD基因突变阴性者（P<0.05）。NPM1基因突变阳性患者1疗程CR率、总CR率均显著高于NPM1基因突变阴性者（P<0.05）;FLT3-ITD基因突变阳性患者1疗程CR率、总CR率均显著低于FLT3-ITD基因突变阴性者（P<0.05）。结论:对老年non-APL患者行FLT3-ITD及NPM1基因突变检测,可指导临床治疗及疗效评估。     

CpG oligodeoxynucleotides potentiate the antitumor effects of chemotherapy or tumor resection in an orthotopic murine model of rhabdomyosarcoma.

PURPOSE: CpG oligodeoxynucleotides (ODNs) are synthetic DNA sequences that mimic bacterial DNA and have potent immunostimulatory effects on dendritic cells (DCs), B cells, and natural killer cells. To evaluate CpG ODN antitumor effects against solid tumors, we used an orthotopic murine model of embryonal rhabdomyosarcoma. Experimental Design: The systemic administration of CpG 2006 was tested beginning on day 9 or 19 when tumors were not yet palpable or palpable, respectively, and after surgical resection of the tumor. CpG was also administered in combination with the chemotherapeutic agents, cyclophosphamide (CY) and topotecan, or surgical resection. RESULTS: Systemic CpG prolonged survival when begun at day 9 but had no effect with a large tumor burden. CpG administered after surgical resection of tumor significantly improved survival of mice (P < 0.03). On day 9, CY plus CpG 2006 resulted in improved survival compared with CY alone (70% versus 41%, respectively). Survival was significantly improved when CpG 2006 was administered systemically with CY beginning on day 19 (15% versus 0% survival). The administration of CpG 2006 with topotecan significantly improved survival in mice with large tumors. Cell-depletion studies demonstrated that the antitumor effects of systemically administered CpG 2006 combined with CY were predominantly T cell dependent. CONCLUSIONS: These data are the first to show that immune stimulatory agents such as CpGs may enhance the antitumor effects of chemotherapeutic agents and improve survival after surgical resection of a solid tumor.     

Immune-mediated tumor regression induced by CpG-containing oligodeoxynucleotides.

T-cell based immunotherapy is an attractive approach for the treatment of multiple tumor types including cervical carcinoma. Immunostimulating DNA containing unmethylated cytosine-guanine (CpG) motifs have been successfully used as adjuvants to enhance immune responses to vaccines designed to trigger antitumor T-cell responses. Using a murine model of cervical carcinoma, we report here that repeated administration of synthetic oligodeoxynucleotides bearing CpG motifs (CpG-ODNs) without the need of vaccination into animals bearing large, established tumors resulted in significant antitumor effects. Both tumor regressions and extended survival resulting from CpG-ODN therapy required the participation of CD8+ T cells. On the other hand, CD4+ T cells were not only not required, but also appeared to inhibit the therapeutic effect of CpG-ODN. Tumor regression correlated with increased infiltration of CD8+ T cells into the tumors and with enhanced expression of MHC class I and II antigens by the tumor cells. Together, these results indicate that CpG therapy could be promising as a single agent for the treatment of some tumors such as cervical carcinoma.     

树突状细胞局部免疫抗瘤作用的初步研究

目的：探讨树突状细胞（ＤＣ）瘤内注射的局部免疫方式对小鼠Ｈ２２肿瘤的治疗效果。方法：体外诱导生成树突状细胞,经Ｈ２２肿瘤裂解抗原致敏,实验分为对照组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组,分别与Ｔ细胞共培养,收获的Ｔ细胞与肿瘤细胞共培养,观察其对肿瘤细胞的杀伤。体内试验：ＢＡＬＢ／ｃ小鼠皮下接种Ｈ２２肿瘤细胞制作成荷瘤鼠,第４天时进行局部瘤内免疫治疗,分为３组：生理盐水组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组,免疫治疗１０天后处死小鼠,观察其治疗小鼠Ｈ２２肿瘤的效果。结果：体外实验中,对照组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组的肿瘤杀伤率分别为（１０.８０±３.２７）％、（３８.２６±５.６０）％和（４２.６６±９.００）％,后两组杀伤率均高于对照组（Ｐ＜０.０１）;体内实验中,生理盐水组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组的平均瘤重（ｇ）分别为１.８０４±０.４２２、１.２１６±０.３３５和０.７３３±０.１９１（Ｐ＜０.０１）。结论：ＤＣ瘤苗局部瘤内注射可抑制小鼠Ｈ２２肿瘤的生长,联合应用非甲基化ＣｐＧ-ＯＤＮ可以明显提高抑瘤效果。     

Finding the next Gleevec: FLT3 targeted kinase inhibitor therapy for acute myeloid leukemia

Activating mutations in the FLT3 receptor tyrosine kinase occur in 30% of patients with acute myeloid leukemia. Small molecule FLT3 kinase inhibitors show selective antitumor activity in preclinical models. Clinical studies are underway.     

FLT3 ligand enhances the cancer therapeutic potency of naked RNA vaccines

Intranodal immunization with antigen-encoding naked RNA may offer a simple and safe approach to induce antitumor immunity. RNA taken up by nodal dendritic cells (DC) coactivates toll-like receptor (TLR) signaling that will prime and expand antigen-specific T cells. In this study, we show that RNA vaccination can be optimized by coadministration of the DC-activating Fms-like tyrosine kinase 3 (FLT3) ligand as an effective adjuvant. Systemic administration of FLT3 ligand prior to immunization enhanced priming and expansion of antigen-specific CD8(+) T cells in lymphoid organs, T-cell homing into melanoma tumors, and therapeutic activity of the intranodal RNA. Unexpectedly, plasmacytoid DCs (pDC) were found to be essential for the adjuvant effect of FLT3 ligand and they were systemically expanded together with conventional DCs after treatment. In response to FLT3 ligand, pDCs maintained an immature phenotype, internalized RNA, and presented the RNA-encoded antigen for efficient induction of antigen-specific CD8(+) T-cell responses. Coadministration of FLT3 ligand with RNA vaccination achieved remarkable cure rates and survival of mice with advanced melanoma. Our findings show how to improve the simple and safe strategy offered by RNA vaccines for cancer immunotherapy.     

Antileukemic activity of Flt3 ligand in murine leukemia

Flt3-ligand (Flt3-L) is an early acting costimulatory cytokine that has been shown to possess antitumor properties in murine solid tumor models. Flt3-L is a trans-membrane protein (tm) but can be proteolytically cleaved to a soluble form, which is also biologically active. In this study, the antitumor effect of both soluble and tmFlt3-L was evaluated in a mouse leukemia model. To mimic the multiorgan involvement characteristic of human leukemia, a factor-dependent cell line FDC.P1 was made leukemogenic by transfection with the human BCR/ABL gene. The resulting cell line, AW, expresses BCR/ABL RNA and protein. It maintains a similar in vitro growth rate as the parent cell line, but unlike the parent cell line, AW cells are factor independent and tumorigenic. Growth of FDC.P1 and AW cells are unaffected by the addition of soluble human Flt3-L to the culture medium. Also, AW growth is unaltered after transduction with a retroviral vector expressing the tm isoform of human Flt3-L (AW/tmFlt3-L). When 10(5) AW cells were i.v. injected into syngeneic DBA/2 mice, fatal leukemia developed in nine of nine (100%) mice within 4-6 weeks with involvement of the blood, bone marrow, spleen, and thymus. Systematic administration of soluble human Flt3-L (500 microg/kg/day) for 10 days protected mice from leukemia, with 11 of 17 mice tumor free at week 8 (64.7%) The tm isoform of Flt3-L also was protective. When 10(4) AW/tmFlt3-L cells were injected i.v. into mice, only 35.7% (5 of 14) developed leukemia versus 100% in control groups. Adoptive transfer of immunity was also demonstrated; T cells obtained from tumor-free animals conferred protection to 87% (seven of eight) naive mice challenged with AW cells. These results demonstrate that both soluble and membrane-bound human Flt3-L has antitumor activity in this leukemia model.     

Antitumor activity of sorafenib in FLT3-driven leukemic cells.

Activating internal tandem duplication (ITD) insertions in the juxtamembrane domain of the FLT3 tyrosine kinase are found in about one fourth of patients with acute myeloid leukemia and have been shown to be an independent negative prognostic factor for survival. We show that sorafenib (BAY 43-9006, Nexavar) potently inhibits FLT3 enzymatic and signaling activities. In HEK293 cells stably transfected with FLT3-WT or FLT3-ITD, sorafenib blocked basal and ligand dependent FLT3-mediated tyrosine autophosphorylation as well as extracellular signal-regulated kinase1/2 and Stat5 phosphorylation. In leukemia cell lines MV4-11 and EOL-1, sorafenib treatment resulted in decreased cell proliferation and inhibition of FLT3 signaling. The growth of the FLT3-independent RS4-11 cell line was only weakly inhibited by sorafenib. Cell cycle arrest and induction of apoptosis were observed upon treatment with sorafenib in MV4-11 and EOL-1 cells. The antitumor efficacy of sorafenib was evaluated against the MV4-11 leukemia grown subcutaneously in NCr nu/nu mice. Doses of 3 and 10 mg/kg administered orally for 14 days resulted in six and nine out of 10 animals with complete responses, respectively. The demonstration that sorafenib exhibits potent target inhibition and efficacy in FLT3-driven models suggests that this compound may have a therapeutic benefit for patients with FLT3-driven leukemias.