Targeting Wnt Canonical Signaling by Recombinant sFRP1 Bound Luminescent Au-Nanocluster Embedded Nanoparticles in Cancer Theranostics.

Secreted frizzled-related protein 1 (SFRP1) is a natural blocker of the Wnt signaling pathway in normal adult cells but is epigenetically silenced in cancer cells leading to aberrant proliferation. In this study, we have reported novel composite nanoparticles fabricated with gold nanocluster embedded chitosan and alginate, bound to bacterially expressed human recombinant sFRP1. The Wnt pathway, which is upregulated in cancer, has been specifically targeted with the nanoparticles to achieve an antiproliferative effect on cancer cells, as evident from reduced levels of downstream molecules, namely, β-catenin, cyclin D1, and survivin. The nanoparticles enabled sustained release of sFRP1 outside the cells, where it is functional. Moreover, remarkable luminescence properties of gold nanoclusters were exploited for binding, imaging, and tracking studies. Co-therapy of sFRP1-loaded nanoparticles with the drug cisplatin targeted two independent pathways to induce apoptosis, as documented by flow cytometry based assays. Overall, this nanosystem is promising for tracking, imaging, and targeting cancer signaling with therapeutic protein.