Degradation of Myc protein is mediated by E3 ubiquitin ligases, including SCF(Fbw7) and SCF(Skp2), but much remains unknown about the mechanism of S-phase kinase-associated protein (Skp2)-mediated Myc degradation. In the present study, we show that upregulated Myc protein, which triggers the G1-S phase progression in response to growth-stimulatory signals, induces reactive oxygen species modulator 1 (Romo1) expression. Romo1 subsequently triggers Skp2-mediated ubiquitylation and degradation of Myc by a mechanism not previously reported in normal lung fibroblasts. We also show that reactive oxygen species (ROS) derived from steady-state Romo1 expression are necessary for cell cycle entry of quiescent cells. From this study, we suggest that the generation of ROS mediated by pre-existing Romo1 protein is required for Myc induction. Meanwhile, Romo1 expression induced by Myc during G1 phase stimulates Skp2-mediated Myc degradation in a negative-feedback mechanism.
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http://dx.doi.org/10.1242/jcs.079996 | DOI Listing |
Adv Sci (Weinh)
January 2025
School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China.
Despite substantial advances in the antitumor effects of annonaceous acetogenins (ACGs), the absence of a defined biological action mechanism remains a major barrier to their clinical application. Here, it is found that squamocin effectively depletes both EZH2 and MYC in multiple cancer cell lines, including head and neck squamous cell carcinoma, and gastric and colorectal cancer, demonstrating potent efficacy in suppressing these in vivo tumor models. Through the combination of surface plasmon resonance (SPR), differential scanning fluorimetry (DSF), and cellular thermal shift assay (CETSA), heat shock protein 90α (HSP90α) is identified as the direct binding target of squamocin.
View Article and Find Full Text PDFJ Cell Mol Med
January 2025
Cancer Biology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
This study identifies microRNAs (miRNAs) with significant discriminatory power in distinguishing melanoma from nevus, notably hsa-miR-26a and hsa-miR-211, which have exhibited diagnostic potential with accuracy of 81% and 78% respectively. To enhance diagnostic accuracy, we integrated miRNAs into various machine-learning (ML) models. Incorporating miRNAs with AUC scores above 0.
View Article and Find Full Text PDFActa Neuropathol
January 2025
Pathology Unit, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
The foremost feature of glioblastoma (GBM), the most frequent malignant brain tumours in adults, is a remarkable degree of intra- and inter-tumour heterogeneity reflecting the coexistence within the tumour bulk of different cell populations displaying distinctive genetic and transcriptomic profiles. GBM with primitive neuronal component (PNC), recently identified by DNA methylation-based classification as a peculiar GBM subtype (GBM-PNC), is a poorly recognized and aggressive GBM variant characterised by nodules containing cells with primitive neuronal differentiation along with conventional GBM areas. In addition, the presence of a PNC component has been also reported in IDH-mutant high-grade gliomas (HGGs), and to a lesser extent to other HGGs, suggesting that regardless from being IDH-mutant or IDH-wildtype, peculiar genetic and/or epigenetic events may contribute to the phenotypic skewing with the emergence of the PNC phenotype.
View Article and Find Full Text PDFMol Biol Rep
January 2025
Department of Translational Research, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, 91766-1854, USA.
Cell communication and competition pathways are malleable to Myocardial Infarction (MI). Key signals, transcriptive regulators, and metabolites associated with apoptotic responses such as Myc, mTOR, and p53 are important players in the myocardium. The individual state of cardiomyocytes, fibroblasts, and macrophages in the heart tissue are adaptable in times of stress.
View Article and Find Full Text PDFCurr Genet
January 2025
Center for Functional Genomics of Microbes, Institut Für Genetik Und Funktionelle Genomforschung, Universität Greifswald, Felix-Hausdorff-Straße 8, 17487, Greifswald, Germany.
Basic helix-loop-helix domains in yeast regulatory proteins Ino2 and Ino4 mediate formation of a heterodimer which binds to and activates expression of phospholipid biosynthetic genes. The human proto-oncoprotein c-Myc (Myc) and its binding partner Max activate genes important for cellular proliferation and contain functional domains structure and position of which strongly resembles Ino2 and Ino4. Since Ino2-Myc and Ino4-Max may be considered as orthologs we performed functional comparisons in yeast.
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