Ⅰ型膜型基质金属蛋白酶在癌细胞系中的表达及其与明胶酶A活？…

目的 探讨Ⅰ型膜型基质金属蛋白酶在人肿瘤细胞系中的表达情况及其与明胶酶的分泌和活化的关系。方法 运用逆转录巢式ＰＣＲ,ＲＮＡ印迹分析和蛋白质印迹分析的方法,检测ＭＴ１－ＭＭＰ,ｍＲＮ和ＭＭＰ２蛋白在４个黑色素瘤,２个肺癌和２个前列腺癌细胞系中的表达水平。结果 ＭＴ１－ＭＭＰｍＲＮＡ在所有癌细胞系中均有表达,但表达水平很不一致;在４个黑色素瘤细胞系中的表达水平明显高于肺癌和前列腺癌细胞系;     

不同转移潜能的人肿瘤细胞系金属蛋白酶活性分析

目的探讨不同转移潜能的人类肿瘤细胞的金属蛋白酶（ＭＭＰｓ）活性与其侵袭转移潜能的相关性。方法分别选取具有不同转移潜能的人类肺癌细胞系（ＰＧ、ＰＡａ、ＢＥ１、ＣＬ３、ＬＨ７）、黑色素瘤细胞系（ＷＭ３５、ＷＭ１３４１ｂ、ＷＭ９８３ａ、ＷＭ４５１）及前列腺癌细胞系（ＰＣ，ＰＣ３Ｍ），经细胞培养，条件培养基的收集与浓缩，利用明胶Ｚｙｍｏｇｒａｐｈｙ法检测以上各组细胞ＭＭＰ２和ＭＭＰ９的产生及活性差异，并将这种差异与各自的转移潜能联系起来。结果转移能力相对较高的细胞系产生ＭＭＰｓ的能力相应强于转移能力相对较低者：ＰＧ高于ＰＡａ，ＢＥＩ高于ＣＬ３和ＬＨ７。在进展期黑色素瘤株ＷＭ９８３ａ和转移瘤株ＷＭ４５１出现了ＭＭＰ９的表达，早期瘤株则无。前列腺瘤细胞ＰＣ３的转移性克隆ＰＣ３Ｍ的条件培养基中有较高的ＭＭＰ９活性。结论肿瘤细胞的侵袭转移潜能与其产生ＭＭＰｓ的能力密切相关。     

B7/CD28和ICAM-1/LFA-1共刺激信号对T及B细胞功能影响的研究

目的　研究共刺激途径Ｂ７／ＣＤ２８ 和ＩＣＡＭ１／ＬＦＡ１ 对Ｔ 细胞活化以及Ｂ 细胞效应的作用。方法　在体外建立ＡＰＣＴＢ 细胞反应系统, 用Ｂ７１ 单抗和ＩＣＡＭ１ 单抗分别阻断Ｂ７／ＣＤ２８ 和ＩＣＡＭ１／ＬＦＡ１ 共刺激途径, 利用３ ＨＴｄＲ 法检测Ｔ 细胞增殖,ＥＬＩＳＡ 法测定Ｂ 细胞分泌的抗体, 用ＲＴＰＣＲ 法检测细胞因子基因的表达。结果　Ｂ７１ 单抗和ＩＣＡＭ１ 单抗均可抑制Ｔ 细胞增殖及ＩＬ２ 的产生。Ｂ７１ 单抗可下调Ｂ 细胞抗体的产生（ Ｐ＜ ０ ．０５） , 而ＩＣＡＭ１ 单抗未见明显的抑制（ Ｐ＞ ０ ．０５） 。Ｂ７１ 单抗和ＣｓＡ 联用能阻断Ｔ 细胞增殖活性及Ｂ 细胞的效应, 而ＩＣＡＭ１ 单抗和ＣｓＡ联用则无此作用。Ｂ７１ 单抗能下调ＩＬ２ 和ＩＦＮγｍ ＲＮＡ 表达,Ｂ７１ 单抗和ＣｓＡ 联用则阻断ＩＬ２ 和ＩＦＮγｍ ＲＮＡ 表达,ＩＬ４ 和ＩＬ１０ ｍ ＲＮＡ 仍可表达。结论　Ｂ７／ＣＤ２８ 和ＩＣＡＭ１／ＬＦＡ１ 共刺激途径在Ｔ 细胞活化中具有不同的作用,Ｂ７１ 单抗和ＣｓＡ 联用可导致Ｔ 细胞功能失活即无能。     

T细胞耐受的诱导及其机理研究

目的　阐明抗原特异性 Ｔ 细胞无能的诱导条件、无能细胞的特性及其耐受的机理。方法　抗 Ｂ７１ 单抗与 Ｃｓ Ａ 联用诱导抗原特异性 Ｔ 细胞无能, 通过３ Ｈ Ｔｄ Ｒ 掺入法测定 Ｔ 细胞增殖和 Ｍ Ｌ Ｒ, 利用 Ｒ Ｔ Ｐ Ｃ Ｒ 检测细胞因子基因表达。结果　耐受 Ｔ 细胞与异体淋巴细胞比例为０ ．０１∶１时, 可显著抑制 Ｍ Ｌ Ｒ, 转染 Ｂ７１ 分子的 Ｍ Ｄ Ａ４５３ 和３ Ａ Ｏ 能协同刺激 Ｃ Ｄ３ 诱导的 Ｔ 细胞增殖,不表达 Ｂ７ 分子的 Ｍ Ｄ Ａ４５３ 和３ Ａ Ｏ 无此作用。 Ｐ Ｈ Ａ、 Ｃ Ｄ３ 单抗、 Ｐ Ｍ Ａ＋ Ａ２３１８７ 可以逆转本试验所用诱导方法所致的 Ｔ 细胞的耐受状态。无能 Ｔ 细胞 Ｉ Ｌ２ 和 Ｉ Ｆ Ｎγｍ Ｒ Ｎ Ａ 不表达, 而 Ｉ Ｌ４ 和 Ｉ Ｌ１０ ｍ Ｒ Ｎ Ａ可表达。无能 Ｔ 细胞活化后, Ｉ Ｌ２ 和 Ｉ Ｆ Ｎγｍ Ｒ Ｎ Ａ 能够表达。结论　抗原特异性 Ｔ 细胞耐受是可以人为诱导的, 无能 Ｔ 细胞细胞因子基因格局向 Ｔ Ｈ２ 细胞偏离。     

McAb共激活T细胞介导肝癌细胞前后的膜分子与TCRVβ基因的表达

Ｔ淋巴细胞活化是一个涉及多种膜表面分子和受体以及一系列相关多肽的复杂过程，为了使Ｔ细胞发挥更好的识别和杀伤癌细胞的功能，采用抗ＣＤ３、ＣＤ２８、ＣＤ８０（Ｂ７１）、ＣＤ２、ＣＤ５８ＭｃＡｂ分别刺激健康人ＰＢＬｓ后作用肝癌细胞，对作用前后ＰＢＬｓ用ＦＡＣＳ进行表型分析，结果发现：作用后ＣＤ３和ＣＤ８分子表达比作用前明显增高，而ＣＤ４分子无显著变化，同时基因家族采用ＲＴＰＣＲＳｏｕｔｈｅｒｎ印迹分析ＴＣＲＶβ基因１～２０亚家族表达水平与特征，健康人ＰＢＬｓ分别加入ＩＬ２、ＰＨＡ、抗ＣＤ３和ＣＤ３＋ＣＤ２８、ＣＤ２８＋ＣＤ８０、ＣＤ２＋ＣＤ５８作用肝癌细胞（ＢＥＬ７４０２）前表达水平平均约为５％，作用ＢＥＬ７４０２后表达水平约为１３％～２５％，其特征为Ｖβ７增高，这提示在癌抗原的参与下ＭｃＡｂ共刺激的Ｔ细胞活化，ＴＣＲ接受ＡＰＣ相应抗原的刺激，具有该ＴＣＲ的淋巴细胞迅速增殖而成为针对抗原的Ｔ细胞克隆，发挥其识别和杀伤癌细胞的作用，这将为肿瘤生物治疗的研究提供分子免疫学依据。     

体内持续存在的产生1型及2型细胞因子的不同型CD8T细胞亚群

未活化的ＣＤ８Ｔ细胞能够被抗原和细胞因子活化,成为产生１型细胞因子ＩＦＮγ和ＩＬ２的效应细胞ＴＣ１或产生２型细胞因子ＩＬ４、ＩＬ５及ＩＬ１０的效应细胞ＴＣ２。Ｔ细胞活化的初始阶段环境中的细胞因子决定着Ｔ细胞的分化方向,但它是否还决定着体内持续存在的记忆细胞产生细胞因子的性质,这在ＣＤ４Ｔ细胞已经得以肯定,而在ＣＤ８细胞尚未明确,本文对此进行了研究。方法：未活化ＣＤ８细胞来源于与Ｂ１０．Ｄ２鼠回交的Ｃｌｏｎｅ４ＴＣＲ转基因鼠的脾脏及淋巴结;ＡＰＣ来源于Ｂ１０．Ｄ２鼠的脾脏,与流感病毒血…     

组织金属蛋白酶抑制剂TIMP-2基因转染对胃癌细胞体内外侵袭能力的影响

目的了解ＴＩＭＰ２基因转染对胃癌细胞侵袭行为的影响，进行阻断肿瘤细胞侵袭转移的筛选尝试。方法采取脂质体将外源基因ＴＩＭＰ２导入人胃癌细胞系ＳＧＣ７９０１，经体外Ｂｏｙｄｅｎ小室测定肿瘤细胞侵袭能力与体内肾包膜下瘤组织种植侵袭模型对比分析，观察Ⅳ型胶原酶前体（ＭＴＭＭＰ）与基底膜Ⅳ型胶原免疫组化改变。结果发现转染ＴＩＭＰ２基因的胃癌细胞其表达ＭＴＭＭＰ的能力降低，成瘤时间延长，成瘤率降低，体外与体内的侵袭能力受到抑制。结论ＴＩＭＰ２基因转染可使胃癌细胞的侵袭表型得到下调。     

维吾尔族人群抗原处理相关转运体(TAP)基因多态性及与类风湿关节炎的相关性

目的：探讨新疆维吾尔族人群抗原处理相关转运体（ＴＡＰ）基因多态性及与类风湿关节炎（ＲＡ）的相关性。方法：采用ＰＣＲＡＲＭＳ,ＲＦＬＰ,ＳＳＯＰ检测ＲＡ患者３９例及健康献血者４１例ＴＡＰ１３３３和６３７位,ＴＡＰ２３７９、５６５、６５１、６６５、６８７等位氨基酸等位基因多态性。结果：健康维吾尔族人群ＴＡＰ１３３３位和６３７位等位基因基因型分别以Ｉ和Ｄ为主,表现型主要为Ｉ和ＤＤ,有１Ａ～１Ｄ４个亚型,以１Ａ和１Ｂ为主;ＴＡＰ２３７９、５６５、６５１、６６５、６８７等位基因型分别以ＶＡＲＴＱ为主,表现型以ＶＶＡＴＲＲＴＴＱＱ为主,有２Ａ～２Ｈ共８个亚型,以２Ａ和２Ｂ为主。ＲＡ患者ＴＡＰ２３７９Ｉ,５６５Ｔ和６８７Ｓ频率,５６５ＴＴ,６８７ＳＳ及ＴＡＰ１Ｂ频率显著升高,并且ＴＡＰ１Ｂ可使ＤＲ４阳性者患ＲＡ的相对危险性增加５．３３倍。结论：维吾尔族健康人群及ＲＡ患者ＴＡＰ基因多态性有不同于其他民族人群的基本特点。ＴＡＰ１Ｂ可使ＤＲ４阳性者患ＲＡ的相对危险性增加,并可能是维吾尔患者ＲＡ的易感基因。     

EB病毒活化细胞周期的机制

ＥＢ病毒潜伏感染细胞后表达１０种潜伏蛋白,但只有４种可能与细胞周期的活化有关。这４种潜伏蛋白活化细胞周期的机制各不相同,且与小分子量肿瘤相关ＤＮＡ病毒也不完全相同。其中ＥＢＮＡ２和ＥＢＮＡＬＰ可共同增强周期素Ｄ２的表达,ＥＢＮＡ３Ｃ与ｐＲＢ结合使其释放Ｅ２Ｆ,而ＬＭＰ１则可能通过激活ＮＦκＢ来活化细胞周期。     

IL-4对治疗前后亚急性重型病毒性肝炎患者PBMCs TNF-α和IL-1αmRNA表达的影响

目的　了解白介素（ＩＬ）４ 对重型病毒性肝炎患者外周血单个核细胞（ＰＢＭＣｓ） 中肿瘤坏死因子（ＴＮＦ）α和ＩＬ１αｍＲＮＡ的表达的影响。方法　ＴＮＦα和ＩＬ１αｍＲＮＡ的表达水平采用半定量逆转录聚合酶链反应（ＲＴＰＣＲ） 进行检测。结果　ＩＬ４ 均以剂量依赖的方式抑制治疗前、后亚急性重型肝炎患者ＰＢＭＣｓ ＴＮＦα和ＩＬ１αｍＲＮＡ的表达,在发病初期,ＩＬ４ 于１ ０００Ｕｍｌ 时接近最大抑制效应;而恢复期患者,ＩＬ４ 于１００Ｕｍｌ 时即接近最大抑制效应,剂量－ 反应曲线明显左移。如以１００Ｕｍｌ 的ＩＬ４ 处理ＰＢＭＣｓ,恢复期亚急性重型肝炎患者ＰＢＭＣｓ ＴＮＦα和ＩＬ１αｍＲＮＡ的抑制率接近５０％ 。另外还发现,在发病初期,ＩＬ４ 对内毒素血症和ＨＢｅＡｇ 阳性患者ＰＢＭＣｓＴＮＦα和ＩＬ１αｍＲＮＡ表达的抑制作用低于阴性的患者。结论　ＩＬ４ 对发病初期患者ＰＢＭＣＴＮＦα和ＩＬ１αｍＲＮＡ 表达的抑制作用明显低于恢复期患者,其原因可能与内毒素血症和病毒血症有关     

AAC-11 overexpression induces invasion and protects cervical cancer cells from apoptosis

To identify the genes involved in cervical carcinogenesis, we applied the mRNA differential display (DD) method to analyze normal cervical tissue, cervical cancer, metastatic lymph node, and cervical cancer cell line. We cloned a 491-bp cDNA fragment, CC231, which was present in metastatic tissue and cervical cancer cell line, but absent in normal cervical and cervical cancer tissues. The 491 bp cDNA fragment has 98% homology to the previously published sequence, AAC-11 (antiapoptosis clone 11). The levels of AAC-11 mRNA expressions in nine normal cervical and nine primary cervical cancer tissues were low. Its expression was higher in three metastatic tissues and five cervical cancer cell lines (HeLa, CaSki, SiHa, CUMC-3, and CUMC-6). Invasion of matrigel and adhesion to laminin by AAC-11 transfected CUMC-6 cells were increased by approximately 2-fold and 4-fold, respectively. Northern blot analysis showed that matrix metalloproteinase (MMP)-2 and membrane type 1 MMP (MT1-MMP) genes were found to be expressed in high levels in AAC-11-transfected cancer cells. But MMP-2 and MT1-MMP were not expressed in cells transfected with vector alone or wild-type cells. AAC-11-transfected cells expressed an elevated level of MMP-2 protein as assessed by immunoblotting. On the contrary, tissue inhibitor of MMP (TIMP-2) expression was detectable in cells transfected with vector alone or wild-type cells, respectively. Its expression was undetectable in AAC-11 transfected cells. In cervical cancer cells transfected with AAC-11, the expression of beta-catenin was up-regulated. These suggest that overexpressions of MMP-2 and MT1-MMP, loss of TIMP-2 expression, and up-regulation of beta-catenin by AAC-11 transfection may contribute to the development of cervical cancer invasion. AAC-11 gene transfection increased cervical cancer cell colonization. The effect of AAC-11 on cultured cervical cancer cells was associated with antiapoptotic process. Approximately 50% of the AAC-11 transfected cells in serum-free medium died after 2 weeks, compared to 1 week for vector alone or wild-type cells. These results suggest that AAC-11 may serve as a candidate metastasis-related and apoptosis-inhibiting gene in human cervical cancer.     

Golgi phosphoprotein 3 regulates metastasis of prostate cancer via matrix metalloproteinase 9

Recent studies suggest that Golgi phosphoprotein 3 (GOLPH3) protein is a candidate metastasis gene in human cancer. The goal of this study was to determine the function of GOLPH3 in prostate cancer metastasis and to identify GOLPH3-regulated pathways and genes involved in prostate cancer metastasis. GOLPH3 expression was detected in prostate cancer. To investigate its function, PC-3 cells were stably transfected with shRNA targeting GOLPH3. Cell abilities of invasion and migration were measured in vitro. Downstream regulatory pathways of GOLPH3 were characterized using quantitative RT-PCR and Western blotting analysis. Immunohistochemical studies in prostate cancer specimens revealed a positive correlation of GOLPH3 expression with prostate cancer. GOLPH3 was expressed in prostate cancer cell lines. GOLPH3 repression resulted in the reduction of mRNA level and protein level of MMP9, accompanied with reduced phosphorylation of mTOR, EGFR and Src. Our findings suggest GOLPH3 regulate MMP9 expression which impact cell migration and invasion. This regulation is probably mediated by EGFR and Src signaling pathways.     

婆罗双树样基因4在人前列腺癌细胞和组织中的表达及其与临床预后之间的关系

 目的：评估婆罗双树样基因4（SALL4）在人前列腺癌细胞系和前列腺癌组织中的表达情况,并明确其表达水平和临床病理学参数间的关系。方法：用免疫荧光技术、RT-PCR和Western blotting检测SALL4在LNCaP、DU145、PC-3细胞系和RWPE-1正常前列腺上皮细胞系中的表达。同时用免疫组化方法检测SALL4在前列腺增生及前列腺癌组织中的表达,并探讨其与Gleason评分等临床病理参数的关系。结果： SALL4蛋白在细胞中主要表达于胞浆,在3种前列腺癌细胞株中SALL4蛋白表达水平要明显高于正常前列腺上皮细胞RWPE-1（P＜005）,而SALL4 mRNA表达水平在4种细胞系中无明显差异（P＞0.05）。免疫组化结果显示SALL4在前列腺癌组织中的表达水平明显高于增生和正常前列腺组织（P＜0.01）。SALL4蛋白表达水平与Gleason评分、前列腺癌临床分期、预后及组织前列腺特异抗原（PSA）表达密切相关,而与患者年龄、治疗前血清总PSA水平、前列腺体积及组织雄激素受体表达无明显相关性。结论：SALL4蛋白在前列腺癌中高表达,提示其在前列腺癌的发生、发展过程中可能起重要作用,有可能成为诊断前列腺癌新的肿瘤标志物及评估其恶性程度、进展和预后的参考指标。     

The role of urokinase and urokinase inhibitor in tumour cell metastasis

In this paper we summarize experiments in which murine melanoma B16-F1 cells of low metastatic potential were transfected with the human gene for prep rourokinase. B16-F1 cells selected for their secretion of high amounts of the human urokinase gene product (3- to 4-fold higher plasminogen activator activity than control cells) formed between 4- and 16-fold greater numbers of lung tumours in C57BL mice after tail vein injection. In correlative results, highly malignant B16-F10 melanoma cells transfected with a urokinase antisense sequence showed a significant inhibition of endogenous urokinase expression and a corresponding significant decrease in the number of tumours formed after tail vein injection.The human urokinase gene product expressed by the transfected cells does not bind to murine cell surface urokinase receptors, and the results may provide direct evidence for a role of secreted (non-surface bound) urokinase in the extravasation steps of tumour cell metastasis. These human urokinase secreting cells also showed a greater ability to spontaneously metastasize from a primary footpad tumour to the mouse lung.Extending the study of urokinase to the role of its natural inhibitor, plasminogen activator inhibitor 2 (PAI-2), we determined the constitutive and phorbol ester inducibility of the mRNA for PAI-2 and urokinase in human A375 melanoma cell lines and human prostate PC3 carcinoma cell lines of different metastatic potentials. Analysis of the changes in PAI-2 and urokinase mRNA levels indicate that variation in the levels of PAI-2 may be more important than urokinase in explaining the different metastatic abilities of A375 and PC3 sublines. Urokinase activity may promote metastasis by its initiation of a specific proteolysis pathway leading to the activation of metalloproteinases. We have previously shown that the metalloproteinase inhibitor, recombinant tissue inhibitor of metalloproteinases (rTIMP), inhibits B16 melanoma cell lung colonization.     

Differential Expression and Origin of Membrane-Type 1 and 2 Matrix Metalloproteinases (MT-MMPs) in Association with MMP2 Activation in Injured Human Livers

Matrix metalloproteinase-2 (MMP2) activation is associated with basement membrane remodeling that occurs in injured tissues and during tumor invasion. The newly described membrane-type MMPs (MT-MMPs) form a family of potential MMP2 activators. We investigated the localization and steady-state levels of MT1-MMP and MT2-MMP mRNA, compared with those of MMP2 and tissue inhibitor of MMP-2 in 22 hepatocellular carcinomas, 12 liver metastases from colonic adenocarcinomas, 13 nontumoral samples from livers with metastases, 10 benign tumors, and 6 normal livers. MMP2 activation was analyzed by zymography in the same series. The expression of MT1-MMP mRNA and the activation of MMP-2 were increased in hepatocellular carcinomas, metastases, and cholestatic nontumoral samples. MT2-MMP mRNA was rather stable in the different groups. MT1-MMP mRNA levels, but not MT2-MMP mRNA, correlated with MMP-2 and tissue inhibitor of MMP-2 mRNA levels and with MMP2 activation. In situ hybridization showed that MT1-MMP mRNA was expressed in stromal cells, and MT2-MMP mRNA was principally located in both hepatocytes and biliary epithelial cells. Consistently, freshly isolated hepatocytes expressed only MT2-MMP mRNA, and culture-activated hepatic stellate cells showed high levels of MT1-MMP mRNA. These results indicate that in injured livers, MMP2 activation is related to a coordinated high expression of MMP2, tissue inhibitor of MMP-2, and MT1-MMP. Furthermore, the finding of a preferential expression of MT2-MMP in hepatocytes, together with our previous demonstration that the activation of stellate cell-derived MMP2 in co-culture requires interactions with hepatocytes (Am J Pathol 1997, 150:51–58), suggests that parenchymal cells might play a pivotal role in the MMP2 activation process.     

MT2-MMP expression associates with tumor progression and angiogenesis in human lung cancer

Matrix metalloproteinases (MMPs) are a family of important proteolytic enzymes that play an important role in the remodeling of the tumor microenvironment and associate with tumorigenesis and metastasis. We previously reported that membrane type-2 MMP (MT2-MMP) is highly expressed in human esophageal cancer tissues, and its expression level is positively correlated to tumor size and intratumoral angiogenesis. In order to reveal whether MT2-MMP expression is operative in human lung cancer and its underlying physio-pathological role, in the present study, we examined both mRNA and protein expression levels of MT2-MMP in non-small cell lung caner (NSCLC) tissues and in adjacent normal tissues by using real-time RT-PCR and immunohistochemistry respectively, which showed that both MT2-MMP mRNA (P=0.0359) and protein (P<0.0001) expression levels were significantly increased in cancer tissues in contrast to adjacent normal tissues. Moreover, we also found that the MT2-MMP protein level in cancer tissues positively correlated to lymph node metastasis (P=0.0483), tumor stage (P=0.0483), intra-tumoral microvessel density (MVD) (P=0.0445). We have not found statistically significant correlation between MT2-MMP expression and patients’ prognoses, but we found that the patients with both higher MT2-MMP protein expression and higher intra-tumoral microvessel density showed better prognoses than that of the patients with either higher MT2-MMP protein expression or higher intra-tumoral microvessel density (P=0.0311). Thus, our data suggest that MT2-MMP expression positively involves in NSCLC, and might play an important role in promoting the tumor progression and intra-tumoral angiogenesis in NSCLC.     

The metalloproteinase inhibitor TIMP-2 is down-regulated by androgens in LNCaP prostate carcinoma cells

Tissue inhibitors of metalloproteinases (TIMPs) have been shown to perform several biological functions in tumor promotion, principally by their action of inhibiting matrix metalloproteinases (MMPs) at different steps of the metastatic process. In particular, TIMP-2 is involved in a functional complex with the membrane-type 1 (MT1) MMP to convert the secreted MMP-2 progelatinase into the fully active proteolytic enzyme. We used the human, androgen-sensitive prostate carcinoma cell line LNCaP in coculture with the human osteosarcoma cell line OHS to experimentally address the possibility of androgen-dependent regulatory effects on the functional MT1-MMP/TIMP-2/MMP-2 complex upon interaction between prostate carcinoma and osteoblastic cells in metastasis of prostate cancer to bone. In the LNCaP cells a gradual, time-dependent decline in TIMP-2 mRNA expression was observed in the presence of the synthetic androgen analogue R1881 (100 nM), reaching ∼25% of the control level after 48 h of incubation. Consistent with this, the accumulation of secreted TIMP-2 in media from R1881-treated cells was significantly inhibited already after 3 h. Neither MMP-2 gelatinolytic activity nor expression of MT1-MMP was detected in LNCaP cells. In contrast, the OHS cells showed membrane-associated MT1-MMP expression as well as MMP-2 secretion. However, R1881 treatment of the LNCaP/OHS coculture model did not seem to change the overall proteolytic activity of the MT1-MMP/TIMP-2/MMP-2 complex. Hormonal control of TIMP-2 expression in prostate carcinoma cells has not been previously reported, but whether such regulation has any functional role in the development of osteoblastic metastases in prostate cancer is still unclear. This revised version was published online in July 2006 with corrections to the Cover Date.