Abstract
A ligustrazine (TMP) derivative, (E)-2-(2, 4-dimethoxystyryl)-3,5,6-trimethylpyrazine (DLJ14) was synthesized for the improvement of low bioavailability and short half-life of ligustrazine. We have observed potential reversal effects of DLJ14 on adriamycin (Adr)-resistant human myelogenous leukemia cells (K562/A02) and Adr-resistant human breast cancer cells (MCF-7/A) in vitro or in vivo in previous studies. The aim of the present study was to investigate the underlying molecular mechanism of DLJ14 and Adr combination treatment on Adr-resistant human breast cancer. Inhibition of cancer cell growth was estimated by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell cycle distribution was analyzed by flow cytometry and apoptosis determined using Annexin V-FITC/propidium iodide (PI) double staining and Hoechst 33258 nuclear staining. The expression of proteins in the epidermal growth factor receptor (EGFR)/phosphatidylinositol-3 kinase (PI3K)/Akt survival pathway and mitochondrial-mediated apoptosis pathway were measured by Western blotting analysis. Results showed that DLJ14 and Adr combination treatment exhibited stronger inhibition of the survival of MCF-7/A cells than Adr treatment alone. This effect might be associated with its role in cell cycle arrest and apoptosis induction. DLJ14 combined with Adr induced cell cycle arrest in the G2/M-phase by activating p21(wafl /cip1) and p53 in mitochondria and increased cleavage of caspase-9 and caspase-3, and Bax/Bcl-2 ratio. Mitochondrial membrane potential (MMP) disruption and cytochrome c (Cytc) release from mitochondria to cytosol suggested that apoptosis induction might be mediated by the mitochondrial pathway. Moreover, the combination of DLJ14 and Adr could down-regulate the expression of EGFR, p-EGFR, PI3K, and p-Akt in MCF-7/A cells. Overall, DLJ14 and Adr combination treatment may inhibit proliferation of Adr-resistant human breast cancer cells through inhibition of the EGFR/PI3K/Akt survival pathway and induction of apoptosis via the mitochondrial-mediated apoptosis pathway.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
