The COOH-terminal peptide of platelet factor-4 variant (CXCL4L1/PF-4var47-70) strongly inhibits angiogenesis and suppresses B16 melanoma growth in vivo

Mol Cancer Res. 2010 Mar;8(3):322-34. doi: 10.1158/1541-7786.MCR-09-0176. Epub 2010 Mar 9.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiostatic Proteins / chemistry
  • Angiostatic Proteins / pharmacology*
  • Animals
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Biological Assay
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Movement / physiology
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Chick Embryo
  • Disease Models, Animal
  • Humans
  • Melanoma, Experimental / blood supply
  • Melanoma, Experimental / drug therapy*
  • Melanoma, Experimental / physiopathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Nude
  • Neovascularization, Pathologic / drug therapy*
  • Neovascularization, Pathologic / physiopathology
  • Neovascularization, Pathologic / prevention & control
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / chemistry
  • Peptide Fragments / pharmacology*
  • Platelet Factor 4 / agonists
  • Platelet Factor 4 / chemical synthesis
  • Platelet Factor 4 / chemistry
  • Platelet Factor 4 / pharmacology*

Substances

  • Angiostatic Proteins
  • Antineoplastic Agents
  • PF4V1 protein, human
  • Peptide Fragments
  • Platelet Factor 4