Enhanced cytotoxicity of optimized liposomal genistein via specific induction of apoptosis in breast, ovarian and prostate carcinomas

Abstract

Clinical use of genistein against cancer is limited by its extremely low aqueous solubility, poor bioavailability and pharmacokinetics. Based on structural analogy with steroidal compounds, liposomal vehicle compositions were designed and optimized for maximum incorporation of genistein's flavonoid structure. Model conventional and stealth liposomes of genistein (GenLip)--incorporating unsaturated phospholipids and cholesterol--have demonstrated enhanced drug solubilization (over 350-folds > aqueous drug solution), shelf-life stability, and extended release profile. Owing to effective cellular delivery, preservation of genistein's antioxidant activity was confirmed through marked neutralization of peroxides via GenLip, in both quantitative and microscopic fluorescent-probe oxidation assays. Furthermore, significant broad-spectrum anticancer efficacy of GenLip, in murine and human cancer cell lines (p < 0.05-0.001), was achieved in a concentration and time-dependent manner--approx. 5-7 lower IC50 values versus all non-incorporated drug controls. Indicative of key pro-apoptotic activity, GenLip produced DNA laddering, with 1/3 of free drug solution content, and resulted in the highest induction level of P53-independent apoptotic pathway markers, compared to all treatments, in our assays (namely, mitochondrial polarization, and caspase-3/7 enzymes). Our proof-of-principle pharmaceutical design of genistein-loaded liposomes shows optimal loading capacity and physico-chemical properties, which improved cellular delivery and specific pro-apototic effectiveness of incorporated drug, against various cancers.

Layered nanoemulsions as mucoadhesive buccal systems for controlled delivery of oral cancer therapeutics

“…18,19 Combined with mucoadhesive coating, the optimized nanoemulsification of Gen would allow for sustained delivery of this antiproliferative drug candidate into oral carcinoma lesions, due to improved solubilization and permeation through biomembranes.…”

“…The drug encapsulation efficiency in the NE formulations was determined by ultrafiltration technique (MWCO =3,000 Da), using centrifugal filter devices (Centricorn, Millipore, Bedford, MA, USA), followed by HPLC quantification. 18,19,21 stability of Nes and incorporated gen…”

“…At certain coincubation time points (12,24, and 48 hours), after washing twice with HBSS, cell viability was determined using a CellTiter Blue ® Kit and reading sample plate fluorescence at excitation λ =480 nm and emission λ =530 nm, using a Synergy 2 BioTek fluorescence plate reader (BioTek Instruments Inc, Winooski, VT, USA), according to manufacturer's instructions. 18,25 Data analysis A minimum of triplicates were run for each experiment. Data were reported as mean ± SD.…”

“…Liposomal vehicles of Gen markedly induced apoptosis in different solid tumor cell lines of diverse origin, leading to both time-and concentration-dependent improvement in cancer cell repression. 18 Further enhancement of the antiproliferative efficacy of Gen was achieved using surfactant-based vesicles (specifically, polymeric lipid micelles and nanoemulsions [NEs]). 19 In the latter nanocarrier system designs, the active Gen drug molecules served …”

“…Proapoptotic effects of Gen were also associated with mitochondrial depolarization and cytosolic release of cytochrome c, in T-cell lymphoma and acute promyelocytic leukemia cells as well as in human prostate, breast, and hepatic carcinoma cultures. 14,[17][18][19] Despite evident anticancer activity of Gen, its use is limited by its lipophilic nature, extremely low aqueous (AQ) solubility, 20 and extensive metabolism, resulting in poor bioavailability and pharmacokinetic profiles. Thus, nanoscale vehicles have been recently designed and investigated to enhance the solubilization and delivery of Gen for various therapeutic applications, such as antioxidant and cancer chemoprevention.…”