Myc-mediated Apoptosis is Blocked by Ectopic Expression of Bcl-2
Overview
Authors
Affiliations
The product of the c-myc proto-oncogene is an important positive regulator of cell growth and proliferation. Recently, c-Myc has also been demonstrated to be a potent inducer of apoptosis when expressed in the absence of serum or growth factors. To further examine Myc-induced apoptosis, we coexpressed the proto-oncogene bcl2, which has been shown to block apoptosis in other systems, with c-myc in serum-deprived Rat 1a fibroblasts. Here we report that ectopic expression of bcl2 specifically blocks apoptosis induced by constitutive c-myc expression. Constitutive c-myc expression in serum-deprived Rat 1a cells caused a > 15-fold increase in the number of dead cells, accompanied by DNA fragmentation. However, coexpression of bcl2 with c-myc in these cells led to a 10-fold increase in the number of live cells and a significant decrease in DNA fragmentation. Thus, Bcl-2 effectively inhibits Myc-induced apoptosis in serum-deprived Rat 1a fibroblasts without blocking entry into the cell cycle. These results imply that apoptosis serves as a protective mechanism to prevent tumorigenicity elicited by deregulated Myc expression. This protective mechanism is abrogated, however, by Bcl-2 and therefore may explain the synergism between Myc and Bcl-2 observed in certain tumor cells.
miR-142: A Master Regulator in Hematological Malignancies and Therapeutic Opportunities.
Huang W, Paul D, Calin G, Bayraktar R Cells. 2024; 13(1).
PMID: 38201290 PMC: 10778542. DOI: 10.3390/cells13010084.
Co-Operativity between MYC and BCL-2 Pro-Survival Proteins in Cancer.
Fairlie W, Lee E Int J Mol Sci. 2021; 22(6).
PMID: 33799592 PMC: 8000576. DOI: 10.3390/ijms22062841.
Mutations in the RNA Splicing Factor SF3B1 Promote Tumorigenesis through MYC Stabilization.
Liu Z, Yoshimi A, Wang J, Cho H, Chun-Wei Lee S, Ki M Cancer Discov. 2020; 10(6):806-821.
PMID: 32188705 PMC: 8188517. DOI: 10.1158/2159-8290.CD-19-1330.
Farria A, Mustachio L, Coban Akdemir Z, Dent S Oncotarget. 2019; 10(56):5847-5858.
PMID: 31645904 PMC: 6791378. DOI: 10.18632/oncotarget.27226.
Zhang Z, Shi L, Song L, Maurer K, Petri M, Sullivan K Front Immunol. 2018; 9:497.
PMID: 29593737 PMC: 5859352. DOI: 10.3389/fimmu.2018.00497.