Synergetic effect of functional cadmium–tellurium quantum dots conjugated with gambogic acid for HepG2 cell-labeling and proliferation inhibition

Peipei Xu,¹ Jingyuan Li,² Lixin Shi,³ Matthias Selke,³ Baoan Chen,⁴ Xuemei Wang⁵

¹Department of Hematology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China; ²Laboratory Animal Center, Institute of Comparative Medicine, Nantong University, Nantong, People’s Republic of China; ³Department of Chemistry and Biochemistry, California State University – Los Angeles, Los Angeles, CA, USA; ⁴Department of Hematology, Zhongda Hospital, Southeast University, Nanjing, People’s Republic of China; ⁵State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory), Southeast University, Nanjing, People’s Republic of China

Abstract: We prepared and studied novel fluorescent nanocomposites based on gambogic acid (GA) and cadmium–tellurium (CdTe) quantum dots (CdTe QDs) modified with cysteamine for purpose of cancer cell labeling and combined treatment. The nanocomposites were denoted as GA-CdTe. Characterization results indicated that the CdTe QDs can readily bind onto cell plasma membranes and then be internalized into cancer cells for real-time labeling and tracing of human liver hepatocellular carcinoma cell line (HepG2) cells. GA-CdTe significantly enhanced drug accumulation in HepG2 cells and inhibited cancer cell proliferation. GA-CdTe nanocomposites also improved the drug action of GA molecules in HepG2 cells and induced the G₂/M phase arrest of the cancer cell cycle, promoting cell apoptosis. Given the sensitive, pH-triggered release of GA-CdTe, the side effects of GA anticancer agents on normal cells/tissues in the blood circulation markedly decreased. Efficient drug release and accumulation in target tumor cells were also facilitated. Thus, the fluorescent GA-CdTe offered a new strategy for potential multimode cancer therapy and provided new channels for research into naturally-active compounds extracted from traditional Chinese medicinal plants.

Keywords: cadmium-tellurium quantum dots, gambogic acid, drug delivery, cell labeling, therapy