Neochlorogenic acid enhances the antitumor effects of pingyangmycin via regulating TOP2A.

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.

Short-term UV-B dose stimulates production of protective metabolites in Matricaria chamomilla leaves.

Physiological response of two cultivars of Matricaria chamomilla plants on UV irradiation was studied. The impact of used short-time UV dose was evaluated in three time points; 2, 24 and 48 h after irradiation. Used UV irradiation immediately resulted in changes in plant oxidative status monitored as increased concentration of H2 O2 . Decrease in chlorophyll a and b indicated the impact on photosynthetic apparatus. For phenolic secondary metabolites, an increase in total soluble phenols and AlCl3 -reactive flavonols was observed. The activity of main phenolic enzyme, phenylalanine ammonia-lyase, increased with time after irradiation. Significant changes, mainly decreasing trends, in the content of free coumarins and their glycosidic precursors were observed. Enhanced accumulation in chlorogenic and 1,5-dicaffeoylquinic acid and in (Z)-isoform of dicycloethers was detected. From these results, the redirecting precursors of coumarin biosynthesis to biosynthesis of substances with higher antioxidative potential can be assumed. Different reactions in diploid and tetraploid plants were recorded, too.