应用MTT法分析青蒿素对人癌细胞系Hella细胞的体外细胞毒作用

MTT法是一种快速、简便的能够半自动化定量分析细胞增殖及药物细胞毒作用的方法.青蒿素是从天然植物青蒿中提取的有效成分,有关文献曾报道了青蒿素的一些生物活性[1].为了探讨青蒿素的抗癌活性,我们通过体外MTT法分析检测了青蒿素对体外培养的人癌细胞系Hella细胞的细胞毒效应,现报告如下.     

苏木精染色法测定化疗药物对贴壁肿瘤细胞毒性作用的实验研究

目的:建立苏木精染色法检测贴壁细胞增殖活性和化疗药物对贴壁细胞毒性作用的方法.方法:用苏木精染色法测定贴壁肿瘤细胞的增殖活性;同时利用该方法测定长春新碱、5-氟尿嘧啶对M21和SGC7901细胞的毒性作用,以及顺铂对兔VX2细胞的毒性作用;并与MTT比色法进行对比.结果:苏木精染色法测定贴壁肿瘤细胞增殖活性结果与MTT比色法测定结果具有一致性,P>0.01.苏木精染色法测定各化疗药敏结果呈剂量依赖关系,3种肿瘤细胞系5次测定抑瘤率重复性良好(CV<8%),两种方法检测结果一致,P>0.01.结论:苏木精染色法用于贴壁细胞的增殖活性和化疗药物的细胞毒性测定,具有特异、稳定、经济和简便等优点.     

人胃癌原代细胞短期培养与纯化培养体外药敏试验

目的 :评价人胃癌原代细胞短期培养 (混杂非肿瘤细胞 )与纯化培养MTT法体外药敏试验的可行性、各自的优势与缺陷。方法 :采用短期培养MTT比色法测定 7种化疗药物敏感性。另经反复贴壁、胶原酶消化排除、胰蛋白酶消化选择或自然纯化法获得纯的原代肿瘤细胞 ,再行MTT法。测定两种方法细胞数与A(光密度 )值的相关性、药物抑制率及两种方法药敏结果的灵敏性。结果 :短期法MTT药敏试验成功率 81 4% (48/59) ;纯化培养为 50 8% (30 /59) ;两种方法细胞数与A值均呈直线相关 (P均 <0 0 1 ) ,药敏结果具有可比性 ;两种方法 7种药物敏感性顺序一致 ,但纯化法显示 7种化疗药物的抑制率有 6种均高于短期法 ,表明纯化法较敏感 ;纯化培养所需时间平均 (2 0 2± 9 5)天。结论 :人胃癌原代细胞短期培养MTT比色法快捷、简便 ,能够反映化疗药敏结果的基本趋势及个体化差异 ,但灵敏性略低。纯化培养后药敏试验结果更理想 ,但成功率不高     

贲门癌患者肿瘤细胞与外周血淋巴细胞体外药敏试验的相关性研究

目的:探讨贲门癌患者外周血淋巴细胞能否代替肿瘤细胞进行体外药敏试验,以指导不能行肿瘤细胞化疗药敏检测患者的临床化疗。方法:采用MTT法体外药敏试验,检测28例贲门癌患者外周血淋巴细胞和肿瘤细胞对9种临床常用抗癌药物的敏感性。结果:贲门癌患者外周血淋巴细胞与其肿瘤细胞的体外药敏试验对9种抗癌药物的敏感性差异无统计学意义,P值为0·500~1·000。两种细胞药敏试验对5-FU、DDP、CBP、MTX、Vp-16、CTX和THP敏感,对ADM不敏感。结论:贲门癌患者外周血淋巴细胞与其肿瘤细胞对化疗药物的敏感性具有良好的正相关性,外周血淋巴细胞化疗药敏检测对临床选择化疗药物具有重要参考价值。     

酶反应比色法检测细胞介导的细胞毒作用的原理与问题

同位素标记法和酶反应比色法（如ＭＴＴ比色法、ＮＡＧ释放法）是检测ＣＴＬ、ＮＫ细胞、ＬＡＫ细胞等免疫效应细胞细胞毒作用的常用方法。由于后者有简便、经济及不使用放射性同位素等特点,近年来得到了广泛应用,但是它与同位素方法在测定原理上有本质的差别。根据检测原理、计算公式和癌症及癌症化疗患者效应细胞对靶细胞胞毒作用的检测结果,我们认为酶反应比色法并非普遍适用于检测细胞介导的细胞毒作用,特别对用细胞毒药物治疗的患者不宜用此法。     

薏苡仁提取物对原发性肝癌细胞毒性作用的实验研究

目的 :研究康莱特注射液对原发性肝癌细胞的毒性作用。方法 :用MTT法对康莱特等 7种药物的体外抗肝癌细胞活性进行检测。结果 :康莱特与常用的化疗药CP、DDP、5 FU等对肝癌细胞有毒性作用 ,可达 30 %以上。结论 :康莱特注射液对肝癌细胞有较好的毒性作用 ,是一种天然的副作用低的抗癌新药 ,有良好的应用前景。     

康莱特注射液对肝癌化疗增敏作用的实验研究

目的 :研究康莱特 (KLT)注射液对肝癌细胞化疗增敏作用。方法 :用癌细胞药物敏感性试验(MTT法 )测定KLT注射液和 5种化疗药联合作用的敏感度与对照组比较。结果 :KLT注射液联合化疗药的抑瘤率高于单纯化疗药 (P <0 0 5)。结论 :KLT注射液分别和 5 FU、CP、DDP、MMC联用比单纯化学药物治疗肝癌有明显的增敏作用。     

外周血淋巴细胞和骨肉瘤细胞体外化疗药敏相关性研究

目的:研究外周血淋巴细胞和骨肉瘤细胞体外化疗药敏的相关性。方法:采用MTT法体外药敏试验检测30例骨肉瘤患者外周血淋巴细胞和其肿瘤细胞对14种化疗药物的敏感性。结果:经统计学处理,骨肉瘤患者外周血淋巴细胞与其肿瘤细胞的体外药敏试验对14种化疗药物的敏感性差异无显著性(P>0.05)。两种细胞药敏试验对CBP、DDP、EADM、MTX、THP、VM26中度敏感;对ADM、BLM、MMC、VCR低度敏感;对HCPT、DTIC、Vp-16不敏感。结论:骨肉瘤患者外周血淋巴细胞与其肿瘤细胞对化疗药物的敏感性具有良好的正相关性,外周血淋巴细胞化疗药敏检测对临床选择化疗药物具有重要的参考价值。     

康莱特注射液对肝癌化疗增敏作用的实验研究

目的：研究康莱特（KLT）注射液对肝癌细胞化疗增敏作用。方法：用癌细胞药物敏感性试验（MTT法）测定KLT注射液和5种化疗药联合作用的敏感度与对照组比较。结果：KLT注射液联合化疗药的抑瘤率高于单纯化疗药（P＜0．05）。结论：KLT注射液分别和5－FU、CP、DDP、MMC联用比单纯化学药物治疗肝癌有明显的增敏作用。     

肿瘤原代细胞胶原凝胶体包埋化疗药敏检测及其应用

随着肿瘤个体化治疗的提出,化疗药敏检测也不断受到重视.肿瘤原代细胞胶原凝胶体包埋化疗药敏检测技术可以模拟体内用药环境,与临床具有较好的相关性,是近十几年来发展起来的一项体外化疗药敏检测技术,在肺癌、乳腺癌、胃肠癌等的临床与基础研究方面已体现了其实际应用价值.     

肝细胞癌高表达基因TPT1转染对肝细胞系生物学行为的影响

目的 将TPT1转染肝癌细胞系SMMC-7721和肝细胞系L-02,观察肝细胞系生物学行为的变化.方法 将连有TPT1的、带有绿色荧光蛋白标签的真核报告表达载体pEGFP-N3TPT1,通过Lipofectamine分别转染SMMC-7721和L-02细胞,同时设pEGFP-N3对照.采用逆转录聚合酶链反应(RT-PCR)检测TPT1 mRNA水平,四甲基偶氮唑蓝(MTT)法、软琼脂克隆形成实验、细胞周期分析检测细胞增殖和致瘤性.结果 pEGFP-N3TPT1转染后,SMMC-7721细胞TPT1 mRNA相对表达水平与对照组的比值为1.78,L-02细胞TPT1 mRNA相对表达水平与对照组的比值为2.59.pEGFP-N3TPT1转染可明显增强肝细胞的增殖能力,转染SMMC-7721后24、48、72、96h的吸光度(A)值分别为0.80、1.56、2.69和2.94,均高于pEGFP-N3(分别为0.71、1.23、1.92和2.75)和脂质体对照(分别为0.76、1.27、1.89和2.78),差异均有统计学意义(均P＜0.05).在接种500个和1000个细胞时,pEGFP-N3TPT1组软琼脂克隆形成数分别为(6.00±1.73)个和(12.00±2.65)个,pEGFP-N3组软琼脂克隆形成数分别为(1.00±1.00)个和(7.00±1.00)个(P＜0.05).pEGFP-N3TPT1转染后的SMMC-7721细胞增殖指数(P1)为40.9%,高于pEGFP-N3组(26.4%).EGFP-N3TPT1转染正常肝细胞L-02后,24、48、72、96、120 h测得的A值分别为0.87、1.11、1.55、2.12和2.42,均高于pEGFP-N3组(分别为0.65、0.79、1.02、1.49和1.96)和脂质体组(分别为0.67、0.82、0.89、1.56和1.85),差异有统计学意义(P＜0.05);pEGFP-N3TPT1组平板克隆数为(18.00±2.00)个,pEGFP-N3组为(7.00±2.65)个(P＜0.05),但L-02细胞不能在软琼脂中形成克隆.pEGFP-N3TPT1转染后L-02细胞的PI为35.9%,高于pEGFP-N3组(26.1%).结论 TPT1转染可增强肝癌细胞SMMC-7721的恶性表型,促进正常肝细胞L-02的增殖能力,但不能使L-02发生恶性转化.

Abstract：

Objective The aim of this study was to transfect TPT1 into cell lines SMMC-7721 and L-02, seperately, and to observe the changes of biological behaviors of the cell lines. Methods Through lipofectamine, the eukaryotic report expression vector containing TPT1 ORF( open reading frame), pEGFP-N3TPT1, were transducted into hepatocarcinoma cell line SMMC-7721 cells and normal liver cell line L-02 cells, seperately. The transduction was repeated three times in 24 hrs. The differences of biological behaviors between the pEGFP-N3TPT1 and pEGFP-N3 groups were studied by RT-PCR, MTT assay, soft agar colony formation assay and cell cycle analysis. Results The pEGFP-N3TPT1 transfected cells had a high mRNA level in the two cell lines ( P ＜ 0. 05 ) compared with the pEGFP-N3 controls. The ability of proliferation and the soft agar colony formation were enhanced in the SMMC-7721 transducted cells with pEGFP-N3TPT1 compared with that transducted with pEGFP-N3 ( P ＜ 0.05 ), and the cell cycle analysis showed that the cells in the phase G2 + S/M increased after pEGFP-N3TPT1 transduction. In the L-02 cell line, we obtained similar results, pEGFP-N3TPT1 enhanced the colony formation in plate( P ＜0.05 ), but not make it form colony in soft agar. Conclusions TPT1 can enhance malignant phenotype of SMMC-7721 cells and promote the growth of L-02 cells, but not transform L-02 into malignant phenotype.     

Distribution of a hematopoietic-specific differentiation antigen of K562 cells in the human myeloid and lymphoid cell lineages

BALB/c mice were immunized with uninduced K562 erythroleukemia cells and hybridomas were isolated after fusion of immune spleen cells to P3/NS1 murine myeloma cells. One selected hybrid, designated 10L-30, secreted an antibody of subclass immunoglobulin G2a which was specific for hematopoietic cells. Analysis of 10L-30 binding by complement-mediated cytotoxicity, indirect immunofluorescence, solid-phase radioimmunoassay, and mixed hemadsorption assay indicated that the 10L-30 antigen was expressed on the myeloid cell lines K562, KG-1A, KG-1, some B- and T-lymphoid cell lines, and all normal human peripheral blood T-lymphocyte samples tested, but was absent on the more differentiated myeloid cell lines HL-60, ML-2, ML-3, and normal blood granulocytes. Induction of erythroid differentiation in hemin-treated K562 cells caused a 10-fold reduction in 10L-30 binding. Human erythroid and granulocytic progenitor cells, platelets, erythrocytes, and reticulocytes were nonreactive, as were a variety of nonhematopoietic human tumor cell lines. Freshly isolated leukemic bone marrow samples from patients with M5 (2 of 5), M6 (2 of 2), acute lymphoid leukemia (9 of 14), and chronic myeloid leukemia in lymphoid blast crisis (1 of 1) were 10L-30 positive. The combined evidence indicates that the 10L-30 antigen is a normal, hematopoietic-specific differentiation antigen which is strongly expressed on both immature cells of the myeloid lineage and more generally in lymphoid ontogeny. The 10L-30 antigen may be a useful marker of both normal and leukemic hematopoietic differentiation.     

Cisplatin Combined with Metformin Inhibits Migration and Invasion of Human Nasopharyngeal Carcinoma Cells by Regulating E-cadherin and MMP-9

Metformin has been shown to be useful in reducing insulin resistance by restoring sensitivity. Recentevidence suggests that metformin might also possess anti-tumour activity. This study aimed to investigate theeffects of cisplatin combined with metformin on the proliferation, invasion and migration of HNE1/DDP humannasopharyngeal carcinoma (NPC) cells, and to provide a new target for treating metastasis. The MTT assay wasused to assess viability of HNE1/DDP cells after exposure to different concentrations of 2, 5-diaminopyrimidine-4,6-diol (DDP; 2, 4, 8, 16, and 32 μmol·L-1), metformin (5, 10, 15, 20, and 25 μmol·L-1), and 4 μmol·L-1 of DDPcombined with metformin. Wound healing and transwell migration assays were performed to assess cell migrationand invasion, and expression of E-cadherin and MMP-9 was detected using Western blotting. MTT assay resultsshowed that DDP could inhibit the proliferation of HNE1/DDP cells in a time- and concentration-dependentmanner, with an IC50 of 32.0 μmol·L-1  at 24 h (P < 0.05), whereas low concentrations of DDP had almost noinhibitory effects on cell invasion and migration. DDP combined with metformin significantly inhibited cellinvasion and migration. In addition, genes related to migration and invasion, such as those of E-cadherin andMMP-9, showed differential expression in the NPC cell line HNE1/DDP. In the present study, with an increasingconcentration of metformin, the expression of MMP-9 was downregulated whereas that of E-cadherin wassignificantly upregulated. Taken together, our results show that cisplatin combined with metformin has effectson proliferation, invasion, and migration of human NPC cells.     

Vascular endothelial growth factor and soluble FLT-1 receptor interactions and biological implications

Vascular endothelial growth factor (VEGF), binding to an appropriate receptor like FLT, is the main mitogen for endothelial cells and a strong inducer of angiogenesis. A soluble form of VEGF receptor, sFLT-1, specifically binds VEGF and inhibits its activity. The following expression plasmids were used in the experiments: pVEGF plasmid encoding VEGF165, pFGF-2 encoding FGF-2 and psFLT-1 plasmid encoding the soluble form of VEGF receptor, sFLT-1. The interaction between VEGF and sFLT-1 was evaluated using a migration test and ERK1/2 activity utilizing mouse sarcoma cells (L-1). Implication of the VEGF/sFLT-1 action was also visualized using in vivo angiogenesis assay. The conditioned medium (CM) from L-1 phVEGF-165 transfectants stimulated L-1 cell migration more than medium from non-transfected L-1 cells. Media collected from phVEGF-165 transfectants or original L-1 cells only slightly stimulated the migration of cells transfected with psFLT-1. The L-1 cells also showed intensive phospho-ERK1/2 activity when treated with the CM from VEGF transfectants. In vivo tests showed that sFLT-1 effectively suppressed VEGF-mediated angiogenesis without affecting FGF-2-driven angiogenesis. To summarize, this study documented that sFLT-1 released from transfected cells might inhibit cell functions induced by VEGF, but not by FGF. The results obtained from in vivo angiogenesis tests also confirm the antiangiogenic potency of cloned sFLT-1, which can be useful for planning cancer experimental therapy studies.     

稳定干扰SET肝细胞株的生物学鉴定

目的:对稳定干扰SET(patient SE translocation)的肝细胞株进行生物学性状鉴定,为研究SET蛋白在肝细胞中的作用奠定基础。方法:培养人肝L-02细胞、慢病毒载体介导的稳定干扰(siRNA)SET L-02肝细胞及psiRNAc L-02肝细胞(空载体转染细胞),于倒置显微镜下观察细胞形态,利用MTT吸光度与细胞数目间关系绘制生长曲线,采用染色体畸变试验观察染色体有无结构异常,软琼脂克隆实验检测细胞的恶性转化。结果:与正常肝细胞比较,稳定干扰SET肝细胞及psiRNAc肝细胞的生长形态无明显变化,3组细胞的生长曲线趋于一致。染色体畸变分析表明SET基因沉默的人肝L-02细胞染色体结构与数目未发生明显改变。软琼脂克隆实验表明SET基因沉默的人肝L-02细胞未发生恶性转化。结论:SET siRNA的导入未引起细胞生物学特征的改变,遗传性状保持稳定,说明所构建的SE7基因沉默的人肝L-02细胞模型是稳定的,为后续的研究提供了工具细胞。     

DADS下调肌动蛋白解聚因子抑制人结肠癌SW480细胞迁移与侵袭

  目的  研究二烯丙基二硫（diallyl disulfide, DADS）对人结肠癌SW480细胞肌动蛋白解聚因子（actin depolymerizing factor, ADF）表达及肿瘤细胞增殖、迁移与侵袭能力的影响。  方法  MTT、划痕愈合和侵袭实验分别检测DADS对SW480细胞增殖、迁移与侵袭的影响; RT-PCR、Western blot检测DADS对SW480细胞destrin与cofilin1表达的作用。  结果  MTT分析显示, 不同浓度DADS处理SW480细胞24、48、72、96 h后, 可呈时间-剂量依赖性抑制SW480细胞增殖（P < 0.05）。划痕愈合实验显示, 20、30、40、50 mg/L DADS处理48h后, 细胞迁移率分别为55.51%、34.72%、23.23%、12.87%, 较对照组75.86%与DMSO组72.58%明显降低（P < 0.05）, 表明DADS呈浓度依赖性抑制SW480细胞迁移。Transwell侵袭显示, 20、30、40、50 mg/L DADS作用24 h后, 穿膜细胞数呈剂量依赖性分别减少34.67%、50.54%、57.12%、64.59%（P < 0.05）。45mg/L DADS处理SW480细胞24、48 h后, destrin mRNA下调24.7%、60.1%, 蛋白下调30.1%、58.9%（P < 0.05）, 而处理前后cofilin1 mRNA与蛋白表达无显著性差异（P>0.05）。但SW480细胞处理1、15、30、60 min后, p-cofilin1表达呈时间依赖性分别下调18.9%、53.8%、62.1%、78.2%（P < 0.05）。  结论  DADS抑制人结肠癌SW480细胞迁移与侵袭可能与下调destrin和p-cofilin1有关。      

氨甲蝶呤对映体耐药A549细胞株的建立及其生物学特征

 目的 诱导并建立耐氨甲蝶呤对映体的A549细胞株并观察耐药细胞系（L-(+)-MTX/A549、D-(-)-MTX/A549）的生物学特性。 方法 以MTX对映体为诱导剂,采用浓度递增结合低剂量持续诱导方法诱导A549细胞株,建立MTX不同对映体耐药细胞系;倒置相差显微镜观察细胞形态变化;MTT法绘制细胞生长曲线;MTT法检测耐药细胞株的耐药指数;流式细胞仪检测细胞周期和细胞的分裂增殖能力。 结果 L-(+)-MTX/A549、D-(-)-MTX/A549耐药指数分别为6.0的和20.2。倒置相差显微镜观察细胞形态发生了改变;细胞生长曲线显示D-(-)-MTX/A549的增殖略慢于亲本细胞,而L-(+)-MTX/A549的增殖最慢;流式细胞仪检测细胞周期结果显示L-(+)-MTX/A549、D-(-)-MTX/A549耐药细胞株S期细胞数量减少(P<0.05),G₀/G₁期细胞增多(P<0.05);CFSE检测A549、L-(+)-MTX/A549、D-(-)-MTX/A549的MFI分别为(6.08±0.55)、(7.72±0.30)、(6.90±0.18)。两对映体细胞株间有明显手性差异。 结论 本研究建立了MTX两种对映体耐药细胞株,为进一步研究其耐药机制提供了一种实验模型。     

Serum soluble interleukin 2 receptor levels in patients with breast cancer

Preoperative levels of serum soluble interleukin-2 receptor (1L-2R) were examined in 37 patients with breast cancer. We investigated the correlations of serum soluble IL-2R levels with various factors such as stage grouping, lymph node metastasis, distant metastasis, tumor size, histophthological type, estrogen receptor (ER), progesterone receptor (PgR) and CA 15-3. Serum soluble 1L-2R levels were measured with an enzyme-linked immunosorbent assay. Levels of serum soluble 1L-2R in the patients with stage III and IV breast cancer were significantly higher than those in the normal controls, and patients with stage I and II breast cancer. Preoperative levels of serum soluble IL-2R in patients with T3 and T4 were also significantly higher than those in patients with T1 and T2. Serum levels of IL-2R in patients with distant metastasis were also significantly higher than those in patients without distant metastasis. Moreover, serum levels of soluble IL-2R in patients with higher CA 15-3 were significantly higher than those in patients with normal CA 15-3 levels. We conclude that preoperative serum soluble IL-2R levels in patients with breast cancer may be a valuable parameter, especially in evaluating whether they have distant metastasis or not.     

Effect of caffeine on cytotoxicity and sister chromatid exchange induction in sensitive and resistant rat brain tumor cells treated with 1,3-bis(2-chloroethyl)-1-nitrosourea

Treatment of 9L and 9L-2 cells, which are, respectively, sensitive and resistant to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), with various concentrations of BCNU followed by treatment with 1 mM caffeine potentiated BCNU cytotoxicity by 10-fold with dose modification factors of 1.5 to 1.7. The synergistic effect of caffeine on cellular toxicity diminished when caffeine was added 6 to 24 h after treatment of BCNU. The number of sister chromatid exchanges (SCEs) induced by treatment with BCNU in both cell lines showed a good correlation with cytotoxicity; the number of SCEs induced in 9L cells is 6-fold higher than the number induced in 9L-2 cells. Caffeine potentiated BCNU induction of SCEs in both 9L or 9L-2 cells by the same amount. Caffeine potentiation of BCNU-induced SCEs was also time dependent and was eliminated by a delay of 6 h between BCNU treatment and addition of caffeine. Caffeine had no effect on the formation and removal of DNA cross-links in either 9L or 9L-2 cells after BCNU treatment as determined with the alkaline elution assay. Eighteen to 24 h after BCNU treatment there was an accumulation of 9L cells in late-S-G2-M phase of the cell cycle which diminished with time. Caffeine treatment potentiated the BCNU-induced accumulation of cells in late-S-G2-M phase of the cell cycle. Our results suggest that caffeine potentiates BCNU cytotoxicity and induction of SCEs by a mechanism that is independent of repair of alkylation products, but that may depend on alterations of cellular replication in BCNU-treated cells.     

Characterization of a novel prostate-specific antigen-activated peptide-doxorubicin conjugate in patients with prostate cancer.

PURPOSE: To evaluate safety and pharmacokinetics (PK), and determine the recommended dose for efficacy studies, of L-377202, a novel peptide conjugate of doxorubicin (Dox) that releases the active metabolites leucine-doxorubicin (Leu-Dox) and Dox on cleavage by membrane-bound prostate-specific antigen (PSA). PATIENTS AND METHODS: Nineteen patients with advanced hormone-refractory prostate cancer were treated intravenously with 71 cycles of L-377202 at escalating dose levels of 20 (n = 1), 40 (n = 3), 80 (n = 4), 160 (n = 3), 225 (n = 6), and 315 mg/m(2) (n = 2) once every 3 weeks. Toxicity, response, and PK of L-377202 were assessed. RESULTS: L-377202 was well tolerated. Dose-limiting grade 4 neutropenia was noted in two of two patients administered 315 mg/m(2) (both patients were able to resume therapy at 225 mg/m(2)). The recommended dose for efficacy studies was 225 mg/m(2), which induced grade 4 neutropenia in one of six patients. PK studies demonstrated that L-377202 was metabolized to Leu-Dox and Dox. PK were linear; after administration of single doses of 225 mg/m(2), the mean area under the concentration-time profiles of L-377202, Leu-Dox, and Dox were 6 micromol x L/h, 4 micromol x L/h, and 1 micromol x L/h, and peak concentrations were 14 micromol/L, 5 micromol/L, and 120 nmol/L, respectively. At 225 and 315 mg/m(2), five patients completed at least three cycles of therapy; two patients had a greater than 75% decrease in PSA, and one patient had a stabilized PSA. No response was noted at dose levels less than 225 mg/m(2). CONCLUSION: This is the first study of selective drug delivery in humans using a novel PSA-activated agent. L-377202 was cleaved to produce detectable levels of the active metabolites Leu-Dox and Dox. L-377202 was well tolerated and established a safe dose level for further study.