The Role of TIMPs in Cell Growth, Tumor Progression and Metastasis

主要活动/具体目标。我们正在进行的研究工作的主要目标是深入了解TIMP家族成员，特别是TIMP-2的mmp独立活动的机制。我们确定了以下具体目标来实现我们的目标：1)检查TIMPs在体外改变癌细胞生长和侵袭潜力中的作用；2)研究TIMPs对体内原发性和转移性肿瘤生长的影响；3)研究TIMP对免疫调节细胞（髓源性抑制细胞（MDSC））向原发肿瘤和转移性壁龛募集的影响4)更好地了解细胞间TIMP的摄取和作用。在先前的实验中，在肿瘤细胞中强制表达TIMP-2，我们已经观察到原发肿瘤生长受到抑制。肿瘤生长的抑制伴随着肿瘤微血管密度计数（cd31 +或CD34+）的统计学显著下降，这是一种抗血管生成作用的测量，以及肿瘤细胞凋亡的增加（也可能是由于抑制血管生成）。出乎意料的是，我们还观察到表达TIMP-2的肿瘤细胞中局灶黏附激酶（FAK）的减少，以及表达TIMP-2和Ala+TIMP-2的肿瘤细胞中FAK磷酸化（Y397）的显著减少。我们观察到FAK和/或AKT （Protein Kinase B， PKB）磷酸化在TIMP-2和Ala+TIMP-2肿瘤组织中均降低，这表明：1)FAK位于AKT信号传导的上游，并且都参与细胞迁移的调节；2)体外表达TIMP-2和Ala+TIMP-2可减少肿瘤细胞的迁移。我们之前报道了内皮细胞中FAK磷酸化降低，其中FAK磷酸化参与控制eNOS活性。我实验室的一个主要重点是研究外源性TIMP-2在小鼠肿瘤模型中的作用。我们正在研究对肿瘤生长和转移的影响，目的是更好地了解可能影响这些过程的机制。这些最近的研究结果表明，TIMP-2对肿瘤和宿主细胞具有多种作用，这些作用结合在一起产生了一种有效的抗肿瘤活性，可以在临床上加以利用。

Major Activities/Specific Objectives. The principal goal of our ongoing research effort is to develop an in depth mechanistic understanding of the MMP-independent activities of members of the TIMP family, in particular TIMP-2. We have identified the following specific objectives to obtain our goals: 1) examine the role of TIMPs in altering the growth and invasive potential of cancer cells in vitro; 2) study to effects of TIMPs on primary and metastatic tumor growth in vivo; 3) study the influence of TIMPs on recruitment of immune-modulatory cells (myeloid-derived suppressor cells (MDSC)) to the primary tumor and metastatic niche4) develop a better understanding of the uptake and role of intercellular TIMP. In prior experiments with forced expression of TIMP-2 in tumor cells we have observed suppression of primary tumor growth. The suppression of tumor growth was accompanied by a statistically significant decrease in tumor microvascular density count (CD 31+ or CD34+), a measure of antiangiogenic effects, as well as by increased tumor cell apoptosis (also possibly due to inhibition of angiogenesis). Somewhat unexpectedly, we also observed a decrease in focal adhesion kinase (FAK) in TIMP-2 expressing tumors and a significant decrease in FAK phosphorylation (Y397) in both TIMP-2 and Ala+TIMP-2 expressing tumor cells. Our observation that both FAK and/or AKT (Protein Kinase B, PKB) phosphorylation is reduced in TIMP-2 and Ala+TIMP-2 tumor tissues is significant in that: 1) FAK is upstream of AKT signaling, and both are involved in regulation of cell migration; 2) TIMP-2 and Ala+TIMP-2 expression reduced tumor cell migration in vitro. We previously reported decreased FAK phosphorylation in endothelial cells where it is involved in control of eNOS activity. A major focus in my lab has been to examine the effects of exogenous TIMP-2 in murine tumor models. We are studying the effects on tumor growth and metastasis with the aim of developing a better understanding of the mechanisms that may affect these processes.These recent findings suggest that TIMP-2 has a variety of effects on both tumor and host cells that combine to produce a potent anti-tumor activity that could be exploited clinically.