Phycoerythrin extract from marine red microalga Porphyridium purpureum inhibits lung cancer progression in zebrafish xenograft model

Marine phycobiliproteins are promising anticancer candidates; although they have shown compelling in vitro activity, their in vivo performance remains underexplored. In this study, we evaluated the anticancer potential of a PE-rich extract from Porphyridium purpureum (P. purpureum) using a zebrafish (Danio rerio) xenograft model. To determine the appropriate concentration for in vivo evaluation, zebrafish embryos were exposed to increasing concentrations (2-50 mu g/mL) of PE-extract to assess survival, hatching rate, and cardiac morphology. The PE-extract was well tolerated at low concentrations and did not induce any evident developmental defects or heart abnormalities. A concentration of 10 mu g/mL was selected for short-term anticancer assessment. For this purpose, Dil-labeled A549, NCI-H1975, and NCI-H322 non-small cell lung cancer (NSCLC) cells were injected into the yolk sac of zebrafish embryos and treated with PE-extract. Tumor progression was monitored by fluorescence imaging over 48 h, and tumor area was quantified using ImageJ. Treatment with PE-extract significantly inhibited tumor progression in NCI-H1975 xenografts (p = 0.03), moderately reduced tumor growth in A549 xenografts, and showed minimal effect on NCI-H322 metastatic cells. The differential response highlights cell line-dependent sensitivity to PE-extract in vivo. Overall, this study supports the potential of PE-extract as a natural anticancer agent against selected NSCLC cells and highlights the zebrafish model as a valuable in vivo platform for preclinical evaluation of marine-derived bioactive compounds.