Potential effects of parietin on apoptosis and cell cycle related genes in SH-SY5Y neuroblastoma cells

Abstract

Background: Ingredients obtained from natural products have been used in cancer treatments for years. High diversity and non-toxicity compared to chemotherapeutic agents are the main reasons for their preference. Lichens having potential for treatment of cancer consist of fungus and 1-2 species of algae. Under the name of lichen substances, many of them have also been synthesized as specific substances. The secondary metabolites in lichens are generally insoluble in water, and have many biological activities such as antiviral, antitumor, antibacterial, and antioxidant; they store in the fungal cell or on the surface of the hyphae and can only be extracted with organic solvents.
 Parietin extracted from lichen species such as xanthoria parietina is an anthraquinone pigment and a secondary metabolite. 
 In our study, the effects of parietin on cytotoxicity, gene expression, migration, invasion, and colony formation in neuroblastoma cells treated with parietin were investigated. The SH-SY5Y neuroblastoma (NB), which is not treated with parietin, was administered as a control group.
 Methods: The IC50 value of the parietin was determined using XTT assay. The total RNA extractions were performed from the cells using the Tri-Reagent kit. The expressions of BCL-XL, BCL-2, MMP2, MMP9, P21, CYCLIN D1, CASAPASE-3, CASAPASE-9, BAX, P53, PUMA, and NOXA genes were investigated by Lightcycler 480 (Roche) using SYBR Green dye. Migration analysis of the control and the dose group cells were performed in accordance with the Wound-healing assay protocol. Invasion activities were determined using the “Invasion Chamber” (BD Biosciences) protocol. The colony assay was treated with crystal violet and the cells were observed under the light microscope.
 Results: The IC50 value of the parietin used for 48-hour treatment on the cells was determined as 35 µM. It was found that the expression levels of BCL-XL, BCL-2, MMP2, MMP9, P21, and CYCLIN D1 mRNA were downregulated, and it was also shown the expression levels of CASAPASE-3, CASAPASE-9, BAX, P53, PUMA, and NOXA to be upregulated. It was determined that parietin suppressed both cell invasion and migration, and colony formation in the neuroblastoma cells. 
 Conclusions: Thus, it can be possible parietin to be used as an alternative, complementary, and supportive agent together with the other drugs in the treatment of neuroblastoma. However, more comprehensive studies supporting these significant effects of parietin will increase its potential in the application.