Journal of Stem Cell Research & Therapy

Apoptosis Differentiation and Viability of Dental Pulp Stem Cells Overexpressing CMyc and Bcl2

Chengfei Zhang^* Department of Endodontics, Comprehensive Dental Care, The University of Hong Kong, China
^*Correspondence: Chengfei Zhang, Department of Endodontics, Comprehensive Dental Care, The University of Hong Kong, China, Email:

Published: 26-Dec-2021

Introduction

The development of cell lines with high cell density, controlled proliferation, apoptosisresistance, and easy adaptation into cultures of serum free media is essential for the success of tissue engineering strategies. This study aimed to examine the effects of co-overexpression of c-myc and bcl-2 on viability, apoptosis and differentiation of Dental Pulp Stem Cells (DPSCs). DPSCs were transduced with premade lentiviral particles of human target c-Myc and bcl-2 consecutively. Western blot results confirmed the over-expression of c-Myc and Bcl-2 in respective cell lines. c-Myc over-expressing DPSC cultures showed an increase in proliferation rate and maximum cell number compared to wild type DPSCs as shown by cell counting kit-8 assay. However, c-Myc overexpression also demonstrated significantly higher apoptotic rates in DPSCs than that of wild type DPSCs when cultured under serum starvation. c-Myc overexpressing DPSCs co-transduced with bcl-2 resulted in reduction of apoptosis levels as shown by cell death detection ELISA kit and caspase-3 colorimetric assay, without affecting the cell proliferation rate. Further, c-Myc overexpression appeared to reduce osteo/odontogenic differentiation capacity, whereas Bcl-2 co-overexpression demonstrated a slight increase in differentiation levels. c-Myc and Bcl-2 co-overexpression increases the cell viability in cell proliferation and reduce apoptosis and cell death in DPSCs.

ental Pulp Stem Cells (DPSCs), which could be obtained in large pools of autologous cells, is considered as a promising population of stem cells in regenerative medicine. However, limited self-renewal and proliferation capacity restrict the applications of DPSCs in clinical setting. Therefore, modification of cell lines to achieve high cell density, enhanced proliferation, apoptosis resistance, and easy adaptation into cultures of serum free media is essential for the success of tissue engineering strategies.

In tissue engineering, optimization of methods in cell culture techniques is a progressing arena as the enhanced knowledge of the complex dynamics in regulation of cell survival and growth contributes to improve the expected outcome. Cell engineering strategies to improve maximal cell number would be a major step towards reaching the goal of optimally engineered tissue constructs. Overexpression of important regulators such as growth factors and cell cycle genes of proliferation and apoptosis pathways is one of the strategies employed in cell culture for the management of cell proliferation.

Discussion

The use of proto-oncogenes to modulate the cell proliferation is a potential solution in enhancing the capacity of DPSCs' use in regenerative medicine. Overexpression of c-myc, a transcription factor that is involved in regulation of cell cycle, has been shown of capable in inducing cell proliferation. The c-myc encodes a nuclear phosphoprotein, which after binding to DNA, plays an essential role in transcriptional activation of target genes, as well as in proliferation and apoptosis. However, c-Myc not only plays an important role in cell proliferation but also acts in induction of apoptosis. Therefore, it appears that cell proliferation and apoptosis are coupled at least when it is under c-Myc regulation. Bcl-2 that is involved in cell survival is a prime candidate to be introduced in cell lines to regulate the apoptosis induced by c-myc. It was shown that Bcl-2 expression effectively inhibits c-Myc-induced apoptosis without affecting the c-Myc mitogenic function. This synergistic interaction between c-Myc and Bcl-2 may have implications for developing cell lines with enhanced potential in tissue engineering.

If the aforementioned properties of c-Myc and Bcl-2 expression could be achieved in target progenitor cells, it could lead to development of cell lines with apoptosis resistance, high cell density, controlled proliferation and easy adaptation into serum free medium. Therefore, in the present study, we aimed to overexpress c-myc and bcl-2 in the DPSCs using premade lentiviral particle transfection technique and examine its effects on DPSCs' viability in cell proliferation, survival and odonto/osteogenic differentiation capacity.