Abstract
Three dimensional (3D) culture in vitro is a new cell culture model that more closely mimics the physiology features of the in vivo environment and is being used widely in the field of medical and biological research. It has been demonstrated that cancer cells cultured in 3D matrices are more radioresistant compared with cells in monolayer (2D). However, the mechanisms causing this difference remain largely unclear. Here we found that the cell cycle distribution and expression of cell cycle regulation genes in 3D A549 cells are different from the 2D. The higher levels of the promotor methylation of cell cycle regulation genes such as RBL1 were observed in 3D A549 cells compared with cells in 2D. The treatments of irradiation or 5-Aza-CdR activated the demethylation of RBL1 promotor and resulted in the increased expression of RBL1 only in 3D A549 cells. Inhibition of RBL1 enhanced the radioresistance and decreased the G2/M phase arrest induced by irradiation in 2D A549 and MCF7 cells. Overexpression of RBL1 sensitized 3D cultured A549 and MCF7 cells to irradiation. Taken together, to our knowledge, it is the first time to revealthat the low expression of RBL1 due to itself promotor methylation in 3D cells enhances the radioresistance. Our finding sheds a new light on understanding the features of the 3D cultured cell model and its application in basic research into cancer radiotherapy and medcine development.
Highlights
Two dimensional cell culture is a traditional culture model which is widely used in the biological and medicinal studies
Whether is there difference in DNA methylation status between 2D and 3D cells, and these difference result in the higher cellular radioresistance in 3D than 2D cells? In current study, we found that the methylation of global DNA decreased gradually after irradiation, and the methylation of the promoter of Retinoblastoma-Like 1 (RBL1) gene may play an important role in the induction of the radioresistance for 3D cells
We found that more 3D A549 cells remained in G0/G1 phase and lower in G2/M phase compared with 2D cells both in unirradiated and irradiated groups
Summary
Two dimensional (monolayer, 2D) cell culture is a traditional culture model which is widely used in the biological and medicinal studies. Compared to the traditional 2D culture, cells cultured in Matrigel demonstrate various differences in survival, proliferation, metabolism, differentiation, genes and proteins expression [9, 10]. Breast cancer cells irradiated by the fractionated dose show specific DNA methylation alterations in several locus (TRAPP9, LINE1 and FOXC1), which are mainly the loss of methylation [31]. These studies suggest a connection among the radiation exposure, epigenetic modulation and carcinogenesis. We found that the methylation of global DNA decreased gradually after irradiation, and the methylation of the promoter of RBL1 gene may play an important role in the induction of the radioresistance for 3D cells Whether is there difference in DNA methylation status between 2D and 3D cells, and these difference result in the higher cellular radioresistance in 3D than 2D cells? In current study, we found that the methylation of global DNA decreased gradually after irradiation, and the methylation of the promoter of RBL1 gene may play an important role in the induction of the radioresistance for 3D cells
Sign-in/Register to view highlights & summary 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.
