(T1530-03-19) Utilization of Polymeric Micelles to Enhance Anticancer Activity through Combined Therapy with Luteolin and Doxorubicin

Purpose: Luteolin (LUT) is a bioactive compound with prominent pharmacological activities, and doxorubicin (DOX) is an anthracycline chemotherapeutic drug that has proven to be effective in treating various types of cancers. Polymeric micelles (PMs) containing biologically active materials have emerged as prospective dosage forms with high drug loading, which can add therapeutic benefit to poorly water-soluble compounds and novel chemical entities more efficiently. PMs are effective in delivering several drugs, such as anticancer drugs, antifungal drugs, flavonoids and drugs targeting the brain. The aim of the current study was to develop PMs of LUT and DOX as a combined delivery system for cancer therapy.

Methods: PMs were prepared by loading LUT and DOX alone (LUT-PMs & DOX-PMs) and in combination (LUT-DOX-PMs) using vitamin E (TPGS): poloxamer 407 and Gelucire 44/14 (GC): poloxamer 407 at 7:3 and 5:5 molar ratios, respectively, via the thin film hydration method. Drug-loaded PMs were characterized before and after lyophilization for their particle size, polydispersity index, zeta potential and morphology by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses. An MTT assay was performed on MCF-7 cells to determine the cytotoxic effect of the different PM formulations. Finally, for the identification of apoptotic cells and discrimination between apoptosis and necrosis, flow cytometry techniques were applied.

Results: PMs were successfully developed and optimized using 74.3% poloxamer 407 with 20.7% vitamin E (TPGS) and 70% poloxamer 407 with 25% Gellucire 44/14. The particle size and polydispersity index were found to be 62.03 ± 3.99 nm and 0.33 ± 0.05 (for samples containing TPGS) and 91.96 ± 5.80 nm and 0.59 ± 0.03 (for samples containing GC), respectively. The zeta potentials of the LUT-DOX-PMs containing TPGS and GC were recorded as -2.27±0.11 and -9.3± 0.10 mV, respectively. The LUT-DOX-PMs showed a spherical structure with approx. The 50-100 nm size range was evident by TEM analysis. The SEM photomicrographs and XRD spectra showed that LUT and DOX were converted to amorphous forms. The MTT assay showed that the combined drug-loaded PMs (LUT-DOX-PMs) treatment led to a reduction in the cell viability of MCF-7 cells compared to drug-free PMs, LUT-PMs and DOX-PMs. The IC50 values were 14.89 ± 1.10, 40.91 ± 1.99, and 62.10 ± 4.41 µg/mL for LUT-DOX-PMs (containing TPGS), LUT-PMs, and DOX-PMs, respectively. Flow cytometry results of the combined LUT- and DOX-loaded PMs (LUT-DOX-PMs) detected a significant reduction in viable cells, and almost all MCF-7 cells underwent apoptosis.

Conclusion: PMs loaded with combined LUT and DOX exhibited significant cytotoxic and apoptotic effects against breast cancer cells

References: Patra A, Satpathy S, Shenoy AK, Bush JA, Kazi M, Hussain MD. Formulation and evaluation of mixed polymeric micelles of quercetin for treatment of breast, ovarian, and multidrug resistant cancers. Int J Nanomedicine. 2018 May 16;13:2869-2881.

Acknowledgements: The authors extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia for funding this research work