Laboratory of Molecular Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium.
Mol Cancer Res. 2010 Mar;8(3):322-34. doi: 10.1158/1541-7786.MCR-09-0176. Epub 2010 Mar 9.
Chemokines influence tumor growth directly or indirectly via both angiogenesis and tumor-leukocyte interactions. Platelet factor-4 (CXCL4/PF-4), which is released from alpha-granules of activated platelets, is the first described angiostatic chemokine. Recently, it was found that the variant of CXCL4/PF-4 (CXCL4L1/PF-4var) could exert a more pronounced angiostatic and antitumoral effect than CXCL4/PF-4. However, the molecular mechanisms of the angiostatic activities of the PF-4 forms remain partially elusive. Here, we studied the biological properties of the chemically synthesized COOH-terminal peptides of CXCL4/PF-4 (CXCL4/PF-4(47-70)) and CXCL4L1/PF-4var (CXCL4L1/PF-4var(47-70)). Both PF-4 peptides lacked monocyte and lymphocyte chemotactic activity but equally well inhibited (25 nmol/L) endothelial cell motility and proliferation in the presence of a single stimulus (i.e., exogenous recombinant fibroblast growth factor-2). In contrast, when assayed in more complex angiogenesis test systems characterized by the presence of multiple mediators, including in vitro wound-healing (2.5 nmol/L versus 12.5 nmol/L), Matrigel (60 nmol/L versus 300 nmol/L), and chorioallantoic membrane assays, CXCL4L1/PF-4var(47-70) was found to be significantly (5-fold) more angiostatic than CXCL4/PF-4(47-70). In addition, low (7 microg total) doses of intratumoral CXCL4L1/PF-4var(47-70) inhibited B16 melanoma growth in mice more extensively than CXCL4/PF-4(47-70). This antitumoral activity was predominantly mediated through inhibition of angiogenesis (without affecting blood vessel stability) and induction of apoptosis, as evidenced by immunohistochemical and fluorescent staining of B16 tumor tissue. In conclusion, CXCL4L1/PF-4var(47-70) is a potent antitumoral and antiangiogenic peptide. These results may represent the basis for the design of CXCL4L1/PF-4var COOH-terminal-derived peptidomimetic anticancer drugs.
趋化因子通过血管生成和肿瘤白细胞相互作用直接或间接地影响肿瘤生长。血小板因子-4（CXCL4/PF-4）是从激活的血小板α-颗粒中释放出来的，是第一个描述的血管生成抑制趋化因子。最近发现，CXCL4/PF-4 的变体（CXCL4L1/PF-4var）比 CXCL4/PF-4 具有更明显的血管生成抑制和抗肿瘤作用。然而，PF-4 形式的血管生成活性的分子机制仍部分不清楚。在这里，我们研究了化学合成的 CXCL4/PF-4（CXCL4/PF-4(47-70)）和 CXCL4L1/PF-4var（CXCL4L1/PF-4var(47-70)）的 COOH 末端肽的生物学特性。两种 PF-4 肽均缺乏单核细胞和淋巴细胞趋化活性，但在存在单一刺激（即外源性重组成纤维细胞生长因子-2）时，同样能很好地抑制内皮细胞的迁移和增殖（25 nmol/L）。相比之下，在具有多种介质（包括体外划痕愈合（2.5 nmol/L 与 12.5 nmol/L）、Matrigel（60 nmol/L 与 300 nmol/L）和鸡胚绒毛尿囊膜试验）的更复杂的血管生成试验系统中进行检测时，发现 CXCL4L1/PF-4var(47-70)的血管生成抑制作用比 CXCL4/PF-4(47-70)显著增强（5 倍）。此外，肿瘤内给予低剂量（总剂量为 7μg）的 CXCL4L1/PF-4var(47-70)可更广泛地抑制 B16 黑色素瘤在小鼠体内的生长，优于 CXCL4/PF-4(47-70)。这种抗肿瘤活性主要是通过抑制血管生成（不影响血管稳定性）和诱导细胞凋亡介导的，这可通过 B16 肿瘤组织的免疫组织化学和荧光染色得到证明。总之，CXCL4L1/PF-4var(47-70)是一种有效的抗肿瘤和抗血管生成肽。这些结果可能为设计 CXCL4L1/PF-4var COOH 末端衍生的肽类抗癌药物提供依据。
