ABSTRACT
Neochlorogenic acid (NCA), a natural compound found in honeysuckle, possesses prominent antiinflammatory and antitumor effects. Pingyangmycin (PYM) induces DNA damage and has been used for the treatment of oral and maxillofacial tumors. Oral care serves an important role in promoting wound healing during chemotherapy in patients with oral squamous cell carcinoma (OSCC). Therefore, the present study aimed to analyze the effects of NCA and PYM on OSCC cells and to investigate the potential underlying mechanism. Reverse transcriptionquantitative PCR and western blotting were conducted to analyze the expression levels of DNA topoisomerase II α (TOP2A) in different OSCC cell lines. TOP2Aoverexpression cells were constructed via transfection of TOP2Aoverexpression plasmids. Following NCA or PYM treatment, cell proliferation was assessed using Cell Counting Kit8 and colony formation assays, whereas cell apoptosis and the cell cycle distribution were assessed via TUNEL staining and flow cytometry, respectively. In addition, the expression levels of apoptosis and cell cyclerelated proteins were detected via western blotting. Moreover, coimmunoprecipitation (CoIP) was conducted to determine whether TOP2A interacted with CDK1. The results of the present study indicated that NCA treatment significantly enhanced the suppressive effects of PYM on OSCC cell proliferation and apoptosis. The results also indicated that PYM arrested the cell cycle in the G0/1 by regulating cyclin dependent kinase 1 (CDK1)/cyclin B1, which was enhanced by the cotreatment of NCA and PYM. In addition, NCA and PYA treatment altered the expression levels of apoptosisrelated proteins. The CoIP assay indicated that TOP2A interacted with CDK1. Moreover, TOP2A overexpression significantly reversed the effects of NCA and PYM treatment on OSCC cell proliferation and apoptosis. In addition, NCA significantly decreased PYMinduced toxicity in normal oral epithelial cells. In conclusion, the results of the present study suggested that NCA may promote the inhibitory effects of PYM in OSCC via TOP2A.
Subject(s)
Antineoplastic Agents/pharmacology , Bleomycin/analogs & derivatives , Chlorogenic Acid/analogs & derivatives , DNA Topoisomerases, Type II/metabolism , Neoplasm Proteins/metabolism , Neoplasms , Poly-ADP-Ribose Binding Proteins/metabolism , Quinic Acid/analogs & derivatives , Bleomycin/agonists , Bleomycin/pharmacology , Cell Line, Tumor , Chlorogenic Acid/agonists , Chlorogenic Acid/pharmacology , Humans , Neoplasms/drug therapy , Neoplasms/metabolism , Neoplasms/pathology , Quinic Acid/agonists , Quinic Acid/pharmacologyABSTRACT
In a survey of crude plant extracts for DNA polymerase beta lyase inhibitors, the hexanes extracts of Cladogynus orientalis, Hymenache donacifolia, and Heteropsis integerrima, and the methyl ethyl ketone extract of Acacia pilispina were found to exhibit good inhibition of the dRP lyase activity of DNA polymerase beta. Bioassay-guided fractionation of these extracts led to the isolation of three DNA polymerase beta lyase inhibitory phytosterols, namely stigmasterol (1) and beta-sitosterol (2), isolated from the hexanes extracts, and beta-sitosterol-beta-d-glucoside (3), isolated from the methyl ethyl ketone extract. Compounds 1-3 inhibited the DNA polymerase beta lyase activity with IC(50) values of 43.6, 43.3, and 72.4 microM, respectively. Compounds 1 and 2 were found capable of potentiating the action of bleomycin in cultured human tumor cells, consistent with the possibility that lyase inhibitors may find utility in vivo.
