Foxy-5 TFA

Foxy-5 TFA is the trifluoroacetate salt form of Foxy-5 (CAS No.: 881188-51-8). Foxy-5 is a WNT5A-mimicking peptide (WNT5A-mimicking / Wnt5a agonist), a formylated hexapeptide （sequence: Met-Asp-Gly-Cys-Glu-Leu ）that acts as a WNT5A agonist/mimetic (not an inhibitor or antagonist). Its target is the WNT5A signaling pathway: by mimicking WNT5A to agonize Ryk, Frizzled, and ROR family receptors, it mainly initiates the non-canonical WNT/Ca²⁺ pathway and can cross-talk with the canonical Wnt/β‑catenin pathway. Downstream events involve a series of cascades including PI3K/AKT, MAPK/ERK, β‑catenin, and CXCL12/CXCR4-mediated actin rearrangement and cell chemotaxis. Liu et al. (2024) confirmed by CCK‑8 that the safe dose range of Foxy‑5 in ARPE‑19 cells was 0–300 μmol/L.

For in vitro applications, Foxy‑5 is mainly used in: ① monoculture of the leukemia cell lines HL60, K562, KG1a, and U937, or 2D/3D co-culture with HS‑5 stromal cells, commonly at concentrations of 50 μM and 100 μM for 72 h, for detecting proliferation, ROS, autophagy, and CXCL12-induced migration; ② human retinal pigment epithelial ARPE‑19 cells, in a TGF‑β1 (10 ng/mL)-induced EMT model, with Foxy‑5 used at 50, 100, and 200 μmol/L for 48 h to evaluate EMT/fibrosis-related markers (fibronectin, α‑SMA, nuclear translocation of active β‑catenin, etc.).

In animal experiments, Bueno et al. established a xenograft tumor model by subcutaneously inoculating 8-week-old female NOD/SCID mice with U937 (5×10⁶). After tumors reached 60–100 mm³, therapeutic administration was started: Foxy‑5 2 mg/kg, intraperitoneal injection, once every 2 days, for a total of 9 days. The authors estimated that the circulating concentration in vivo after each i.p. injection was approximately 50 μM. At the end of treatment, the tumor volume inhibition rate was approximately 55.46%, and the tumor weight inhibition rate was approximately 45.51% (P<0.05). In contrast, Liu et al. (2024) used intravitreal injection of FH535 and Box5 only in vivo in a CNV model induced by 532‑nm laser photocoagulation in 7-week-old male C57BL/6J mice; Foxy‑5 was used only for in vitro experiments in ARPE‑19 cells and was not involved in in vivo administration.

It should be emphasized that the effects of Foxy‑5 are markedly tissue / cell type-dependent: in AML cells with low WNT5A expression, it acts as a WNT5A-mimicking tumor suppressor mimetic, inhibiting cell proliferation, ROS production, autophagy, and CXCL12 chemotaxis, and downregulating PI3K/MAPK/β‑catenin signaling; whereas in ARPE‑19 retinal pigment epithelial cells, Foxy‑5, as a Wnt5a agonist, promotes EMT and fibrosis, consistent with the context-dependent “double-sided” effects of WNT5A itself in different tissues.

References:

[1] Bueno MLP, Saad STO, Roversi FM. The antitumor effects of WNT5A against hematological malignancies. J Cell Commun Signal. 2023 Dec;17(4):1487-1499. doi: 10.1007/s12079-023-00773-8. Epub 2023 Jun 13. PMID: 37310653; PMCID: PMC10713930.

[2] Liu D, Du J, Xie H, Tian H, Lu L, Zhang C, Xu GT, Zhang J. Wnt5a/β-catenin-mediated epithelial-mesenchymal transition: a key driver of subretinal fibrosis in neovascular age-related macular degeneration. J Neuroinflammation. 2024 Mar 26;21(1):75. doi: 10.1186/s12974-024-03068-w. PMID: 38532410; PMCID: PMC10967154.