Journal: Scientific Reports

Article Title: Proteomics analysis reveals progesterone receptor induced mitochondria-mediated apoptosis in breast cancer cells

doi: 10.1038/s41598-025-28183-3

Figure Lengend Snippet: Examples of PR regulated proteins and pathways involved in cell proliferation and apoptosis. The quantitative proteomic analysis identified significant changes of thousands of proteins and many hundreds of phosphorylated peptides in response to PR agonist. This figure shows proteins and pathways that were analyzed and interpreted in greater details. (A) Proteins and complexes involved in R5020 induced G0/G1 and G2/M cell cycle arrest, which could also be triggers for apoptosis. (B) PR regulated mitochondrial proteins involved in R5020 induced apoptosis. Significant increases of HIF1A and its downstream targets such as BNIP3 and NIX activated mitophagy together with upregulated LC3. Prolonged increase of BNIP3 and NIX causes mitochondria dysfunction and loss of mitochondria membrane potential. BNIP3 and NIX can sequester anti-apoptotic proteins such as BCL-2 and BCL-XL. This relieved BH3-only proteins, which facilitated formation of BAX and BAK pores on mitochondria outer membrane, leading to MOMPs, cytochrome c release and CASP9 activation, along with upregulation and releases of pro-apoptotic factors such as AIF, ENDOG, HtrA2/Omi, and Smac/DIABLO. PR induced apoptotic mechanism may also involve some of the 200 mitochondrial proteins regulated by R5020. (C) p53 pathway may also participate in R5020-induced cell apoptosis through upregulation of proteins such as death receptors FAS, DR4 and DR5. Upregulation of MDM2 is involved in a negative feedback regulation of p53. (D) TNF signaling via NFKB is generally pro-survival. It was found to be markedly upregulated. Gene silencing of its key players BIRC3 and TNFAIP3 alone or in combination had no influence on R5020 induced downregulation of effector caspases and apoptosis. (E) True to the holistic nature of proteomic analysis, the study also detected the previously reported upregulation of protooncogenic proteins by R5020, but the upregulation of these proteins are futile and should not be interpreted as evidence for pro-tumoral activity of PR. Additionally, all effector CASPs detected in the MS data and in immunoblots were downregulation despite R5020 induced apoptosis. *Although CASP6 is marginally increased in MS data and immunoblot, its activation by cleavage is evidently reduced in immunoblot. Blue downward arrow = Downregulation; Red upward arrow = Upregulation.

Article Snippet: BIRC3 , 1:1000 , Cell Signaling Technology, Danvers, MA, USA , 3130.

Techniques: Membrane, Activation Assay, Activity Assay, Western Blot