Pharmacodynamic Studies of Fluorescent Diamond Carriers of Doxorubicin in Liver Cancer Cells and Colorectal Cancer Organoids

Abstract

Background : We recently reported on preferential deposition of bare fluorescent diamond particles FDP-NV-700/800nm (FDP-NV) in the liver following intravenous administration to rats. The pharmacokinetics of FDP-NV in that species indicated short residency in the circulation by rapid clearance by the liver. Retention of FDP-NV in the liver was not associated with any pathology. These observations suggested that cancer therapeutics, such as doxorubicin, linked to FDP-NV, could potentially serve for anti-cancer treatment while sparing toxicities of peripheral organs. Purpose: To generate proof-of-concept (POC) and detail mechanisms of action of doxorubicin-coated FDP-NV-700/800nm (FDP-DOX) as a prospective chemotherapeutic for metastatic liver cancer. Methods: FDP-DOX was generated by adsorption chemistry. Experimental design included concentration and time-dependent efficacy studies as compared with naïve (baren) FDP-NV in in vitro liver cancer cells models. Uptake of FDP-NV and FDP-DOX by HepG-2, Hep-3B and hCRC organoids were demonstrated by flow-cytometry and fluorescent microscopy. FDP-DOX pharmacodynamic effects included metabolic as well as cell death biomarkers Annexin V, TUNEL and LDH leakage. DOX desorpted from FDP-DOX was assessed by confocal microscopy and chemical assay of cells fractions. Results: FDP-DOX efficacy was dose-and time-dependent and manifested in both liver cancer cell lines and human CRC organoids. FDP-DOX was rapidly internalized into cancer cells/organoids leading to cancer growth inhibition and apoptosis. FDP-DOX disrupted cell membrane integrity as evident by LDH release and suppressing mitochondrial metabolic pathways (AlamarBlue assay). Access of free DOX to the nuclei was confirmed by direct UV-Visible fluorescent assay and confocal microscopy of DOX fluorescence. Conclusion:The rapid uptake and profound cancer inhibition observed using FDP-DOX in clinically relevant cancer models, highlight FDP-DOX promise for cancer chemotherapeutics. We also conclude that the in vitro data justify further investment in in vivo POC studies.

Bioengineered Organoids Offer New Possibilities for Liver Cancer Studies: A Review of Key Milestones and Challenges

“…Purine metabolism, therefore, could be a potential target for personalized therapy. Preferential deposition of fluorescent nano-diamond particles (FDP) coated with doxorubicin, a chemotherapy agent, allows growth inhibition and cell death selectively in tumor cells, thus lowering adverse effects [127]. Oroyxlin A (transketolase inhibitor) is a novel anti-cancer drug studied using liver organoids.…”