SFRP2 and NFAT are therapeutic targets in angiosarcoma

血管肉瘤是一种具有高转移潜能的生物侵袭性血管恶性肿瘤， 随后死亡（1）。在诊断血管肉瘤的时候，10 - 25%的患者已经有 转移性疾病所有血管肉瘤患者的2年和5年总生存率分别为50%和30%， 中位总生存期为24个月。对于不可切除的血管肉瘤，基于阿霉素 治疗方案的无进展生存期为5个月，紫杉醇的无进展生存期为7个月。 个月（2）。因此，迫切需要新的治疗方法来提高这种患者的生存率。 高度致命的疾病。我们的实验室最近发现了一种新的信号通路， 血管肉瘤生长在进行乳腺肿瘤血管细胞与正常血管细胞相比的基因组分析时， 通过激光捕获显微切割获得的血管，我们鉴定了分泌型卷曲相关蛋白2（SFRP 2）， 一种在肿瘤内皮中表达增加的基因。SFRP 2是一个33 kd的分泌型蛋白，参与Wnt 信号我们的初步数据显示，通过IHC，SFRP 2蛋白存在于9/9的人血管瘤中， 刺激鸡胚绒毛尿囊膜上的血管生成，诱导内皮细胞迁移和管 形成，并防止缺氧诱导的细胞凋亡。SFRP 2在SVR血管肉瘤细胞中的沉默 导致管形成的抑制，并且用SFRP 2刺激内皮细胞导致 核NFATc 3。NFAT是一种转录因子，在介导血管生成中起关键作用， 答案（3;4）。NFAT核定位取决于核材料之间的动态进出口平衡。 Ca 2 +/钙调蛋白依赖性磷酸酶、钙调神经磷酸酶的活性和丝氨酸/苏氨酸的活性 激酶（20）。NFAT通常不能进入细胞核，直到它被去磷酸化，但可以被激活， 钙调神经磷酸酶激活的钙调磷酸酶使NFAT去磷酸化，然后从细胞质易位到细胞质。 在细胞核中表达，并导致参与细胞生长、分化和细胞周期进程的基因的转录。 他克莫司（FK 506）是一种免疫抑制药物，与淋巴细胞中的免疫球蛋白FKBP 12结合。 FK 506-FKBP 12复合物与钙调磷酸酶结合并抑制其磷酸酶活性，从而抑制 NFAT核转位（5）。我们的初步数据显示，他克莫司抑制血管肉瘤管 体外形成和全身给药抑制了SVR血管肉瘤裸鼠移植瘤的生长 小鼠在20天时减少了46%。综上所述，我们的数据使我们提出以下假设： SFRP 2将减少血管生成和血管肉瘤生长，并将协同改善肿瘤消退 联合化疗和抗血管生成治疗。本研究的目的是显示 这些药物单独治疗以及与化疗和抗血管生成药物联合治疗血管肉瘤的疗效 治疗，并阐明其抑制肿瘤生长的分子机制。成功完成 该项目将在未来的研究中导致这些药物在血管肉瘤患者中的临床试验。

Angiosarcoma is a biologically aggressive vascular malignancy with a high metastatic potential and subsequent mortality(1). At the time of diagnosis of angiosarcoma, 10¿ 25% of patients already have metastatic disease. The 2- and 5-year overall survival for all patients with angiosarcoma is 50 and 30%, respectively, with a median overall survival of 24 months. For unresectable angiosarcoma, doxorubicin based regimens yield progression-free survival of 5 months, and paclitaxel achieves a progression-free survival of 7 months(2). Therefore there is a desperate need for novel therapies to improve survival in patients with this highly lethal disease. Our laboratory has recently discovered a novel signaling pathway responsible for angiosarcoma growth. While conducting genomic profiling of breast tumor vascular cells compared to normal vessels obtained by laser capture microdissection, we identified secreted frizzled related protein 2 (SFRP2) as a gene with increased expression in tumor endothelium. SFRP2 is a 33kd secreted protein involved in Wnt signaling. Our preliminary data shows that SFRP2 protein is present in 9/9 human angiosarcomas by IHC, and stimulates angiogenesis on the chick chorioallantoic membrane, induces endothelial cell migration and tube formation, and protects against hypoxia induced apoptosis. Silencing of SFRP2 in SVR angiosarcoma cells resulted in inhibition of tube formation, and stimulation of endothelial cells with SFRP2 resulted in an increase in nuclear NFATc3. NFAT is a transcription factor that plays a critical role in mediating angiogenic responses(3;4). NFAT nuclear localization is dependent on a dynamic import-export balance between the activity of the Ca2+/calmodulin-dependent phosphatase, calcineurin, and the activity of serine/threonine kinases(20). NFAT cannot normally enter the nucleus until it is dephosphorylated, but can be activated by calcineurin. Activated calcineurin dephosphorylates NFAT, which then translocates from the cytoplasm to the nucleus and results in transcription of genes involved in cell growth, differentiation, and cell cycle progression. Tacrolimus (FK506) is an immunosuppressive drug that binds to the immunophlin FKBP12 in lymphocytes. The FK506-FKBP12 complex associates with calcineurin and inhibits its phosphatase activity, which inhibits nuclear translocation of NFAT(5). Our preliminary data shows that tacrolimus inhibits angiosarcoma tube formation in vitro, and systemic administration inhibits the growth of the SVR angiosarcoma xenograft in nude mice by 46% at 20 days. Taken together, our data leads us to propose the following hypothesis: Blockade of SFRP2 will decrease angiogenesis and angiosarcoma growth and will synergistically improve tumor regression in combination with both chemotherapy and antiangiogenic therapy. The objective of this study is to show the efficacy of these drugs in angiosarcoma alone, and in combination with chemotherapy and antiangiogenic therapy, and to elucidate their molecular mechanism in inhibiting tumor growth. Successful completion of the project will lead to clinical trials of these agents in patients with angiosarcoma in future studies.