Delivery of chemotherapeutic drug targeting folate receptor to oral cancer cells using functionalized carbon nanospheres

Abstract

Folate receptor (FR) (α) has long been the subject of active interest as regards its potential to serve as a target for cancer therapy. FR has been found to be overexpressed in several cancers, including clinical samples of different stages from OSCC (oral squamous cell carcinoma) patients. However, no clear correlation or conclusive finding has been obtained so far which might indicate the efficacy of FR as a credible target for the treatment of OSCC. All cell lines to be used were assessed for FR-expression. Subsequently, we developed glucose-derived carbon nanospheres (CSPs) and primed them with a Folate-based cationic lipid FA8 and the chemotherapeutic drug doxorubicin (DOX). CSP based delivery systems along with pristine drug DOX were characterized and treated subsequently to in vitro cultures of OSCC cells and assessed for cancer cell targetability as well as cell death. Subsequently, treatment was administered to immunocompetent C57 mice carrying MOC2 based syngeneic OSCC tumours and assessed for tumour regression and toxicity. Ligand primed targeted CSPs exhibited commendable drug uptake as well as efficient induction of cell death. Further, receptor blocking studies revealed FR-mediated uptake, preferentially in cancer cells. Drug once delivered by ligand-primed CSPs was retained longer inside cells than pristine drug alone, indicating possibilities of better therapeutic outcome. In animal studies, CSP-FA8-DOX (Ligand primed targeted CSP) demonstrated significant regression in tumour size compared to pristine DOX as well as CSP-DOX (non-targeted CSP) treated animals. FR-mediated system CFD demonstrated targeted drug uptake and apoptotic death selectively in cancer cells. Significant tumour regression was also observed in vivo. Overall, it may be presumed that the FR is a therapeutic target with substantial potential in OSCC treatment.