Title:Pyrrolidine Dithiocarbamate Enhances the Cytotoxic Effect of Arsenic
Trioxide on Acute Promyelocytic Leukemia Cells
Volume: 26
Issue: 11
Author(s): Simin Yu, Zhuowang Ge, Weixiang Chen and Jinbin Han*
Affiliation:
- Department of Traditional Chinese Medicine, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiao
Tong University, Shanghai, China
Keywords:
Leukemia, dithiocarbamate, arsenic, PML-RARα, apoptosis, cytotoxic effect.
Abstract:
Background: More than 95% patients with acute promyelocytic leukemia (APL) carry
the PML-RARα fusion oncoprotein. Arsenic trioxide (ATO) is an efficacious therapeutic agent for
APL, and the mechanism involves the binding with PML and degradation of PML-RARα protein.
Pyrrolidine dithiocarbamate (PDTC) demonstrates the function of facilitating the cytotoxic effect
of ATO.
Purpose: To investigate whether PDTC is potential to enhance the cytotoxic effect of ATO to APL
cells by acting on PML-RARα oncoproteins.
Methods: Inhibitory effects of drugs on cell viability were examined by CCK-8 test, and apoptosis
was evaluated by flow cytometry. Western blotting and immunofluorescence assays were used to
explore the mechanism.
Results: PDTC improved the effect of ATO on inhibiting proliferation of NB4 cells in vitro. Further,
PDTC-ATO promoted apoptosis and cell cycle arrest in NB4 cells. The expression of caspase-
3 and Bcl-2 was reduced in PDTC-ATO-treated NB4 cells, while cleaved caspase-3 and Bax
was up-regulated. Furthermore, less PML-RARα expression were found in PDTC-ATO-treated
NB4 cells than that in NB4 cells treated with ATO singly. Laser confocal microscopy showed that
protein colocalization of PML and RARα was disrupted more significantly by PDTC-ATO treatment
than that with ATO monotherapy.
Conclusion: In conclusion, PDTC enhanced the cytotoxic effect of ATO on APL, and the mechanism
was, at least in part, related to the promotion of ATO-induced degradation of PML-RARα fusion
protein via forming a complex PDTC-ATO.