Search PubMedSearch

SEARCH · Search PubMed

Results for “Cyclin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Progesterone Is Associated With Increased Vasohibin-2 Expression, Tubulin Detyrosination, and Paclitaxel Sensitivity in PR-Negative Ovarian Cancer Cells.

BACKGROUND: Progesterone induces rapid cellular responses in progesterone receptor (PR)-negative ovarian cancer cells that are consistent with non-genomic progesterone signaling. Vasohibin-2 (VASH2), originally identified as a pro-angiogenic factor, has recently been recognized as a tubulin carboxypeptidase involved in microtubule regulation. AIMS: This study investigated the association of progesterone treatment with VASH2-related molecular changes and paclitaxel sensitivity in ovarian cancer cells. METHODS: Two PR-negative ovarian cancer cell lines expressing membrane progesterone receptors (mPRs) were treated with progesterone. VASH2 mRNA expression was evaluated by RT-qPCR, whereas detyrosinated tubulin and cyclin B1 expression were assessed by western blotting. Paclitaxel and gemcitabine sensitivities were determined using WST-1 cell viability assays. RESULTS: Progesterone treatment was associated with increased VASH2 mRNA expression, enhanced tubulin detyrosination, cyclin B1 accumulation, and significantly reduced paclitaxel IC50 values in both cell lines. In contrast, progesterone had no significant effect on gemcitabine sensitivity. CONCLUSION: Progesterone treatment was associated with increased VASH2 expression, enhanced tubulin detyrosination, and increased paclitaxel sensitivity in PR-negative ovarian cancer cells. These findings provide in vitro evidence supporting further mechanistic and preclinical investigation of progesterone as a potential adjunct to paclitaxel therapy.

Humans

Targeting Mitotic Exit in Malignant Cells.

In order to sustain genomic stability by correct DNA replication and mitosis and thus avoid malignant transformation of cells, the cell cycle is a strictly regulated process. Aberrant cell cycle regulation and defects in mitosis in malignant cells are targets of various cancer therapies. Cancer cells may survive antimitotic treatment due to mitotic slippage with a residual activity of the ubiquitin ligase anaphase-promoting complex (APC/C) and a continuous slow ubiquitin-proteasome-dependent cyclin B-degradation leading to mitotic exit. The combination of antimitotic chemotherapeutics with proteasome inhibitors to block cyclin B-proteolysis or with targeted inhibitors of the APC/C and the antiapoptotic protein Mcl-1 seems a promising approach to improve treatment response in different malignancies by enhancing mitotic arrest and apoptosis.The influence of conventional spindle poisons and new targeted substances and of their combinations on mitosis and apoptosis has not yet been conclusively clarified. Most models have been verified on cell lines whose biology may differ from that of tumors growing in vivo. To study the impact of various antimitotic substances on cell proliferation, especially detect onset of apoptosis depending on different cell cycle phases and thus to identify a possibly entity-dependent mechanism of those agents and their combinations, a combined approach with live-cell imaging and soft-agar colony assays in cultured patient-derived xenografts (PDX) was established.

Humans

CIZ1 regulates G1 length and the CDK threshold for initiation of DNA replication to prevent DNA replication stress.

Eukaryotic cell division is regulated by CDK activity that must reach critical CDK threshold levels to progress through cell cycle stages. In low-mitogen, low-CDK environments, cells exit the cell cycle into a non-proliferative quiescent state, G0, that plays essential roles in stem cell maintenance and cellular homeostasis. CIZ1 regulates cell cycle and epigenetic programmes, and CIZ1 ablation promotes genomic instability after release from quiescence. Here, we show that CIZ1 contributes to mechanisms that temporally regulate cell cycle transitions in post-quiescent cells. CIZ1-/- (CIZ1 KO) fibroblasts re-entering the cell cycle from quiescence have reduced G1 phase and cell cycle length, mediated by increased intracellular CDK activity and early restriction point bypass via G1/S cyclin overexpression. In addition, CIZ1-/- cells are deficient in cyclin A chromatin binding and require increased CDK activity to initiate DNA replication, leading to DNA replication stress. Importantly, ectopic expression of CIZ1 or addition of recombinant CIZ1 reinstates the CDK threshold for initiation of DNA replication, reversing DNA replication stress and increasing replication fork rates. These data suggest that in post-quiescent cells, CIZ1 determines the threshold CDK activity required for the G1/S transition to prevent DNA replication stress.

DNA Replication

Network pharmacology exploration reveals the bioactive compounds and molecular mechanisms of Li-Ru-Kang against hyperplasia of mammary gland.

Li-Ru-Kang (LRK) has been commonly used in the treatment of hyperplasia of mammary gland (HMG) as a cipher prescription and achieved obvious therapeutic effects. However, the bioactive compounds and underlying pharmacological mechanisms remain unclear. This study aims to decipher the bioactive compounds and potential action mechanisms of LRK in the treatment of HMG using an integrated pharmacology approach. The ingredients of LRK and the corresponding drug targets were retrieved through drug target databases and were used to construct the "compound-target-disease" network and function-pathway network. Ultimately, 89 compounds and 2150 drug targets were collected. Gene ontology enrichment analysis revealed that mammary gland alveolus development and mammary gland lobule development were the key biological processes and were regulated simultaneously by three direct targets, including androgen receptor (AR), estrogen receptor (ER) and cyclin-D1. Moreover, 14 compounds of LRK were directly involved in the regulation of the three aforementioned targets. KEGG pathway enrichment analysis found that five signaling pathways and seven direct targets were closely related with HMG treatment by LRK. The results of animal experiments showed that LRK significantly improved the histopathological status of HMG in rats. Additionally, LRK markedly regulated the protein expressions of AR, cyclin-D1, MMP2, MMP3 and MMP9. But interestingly, the effect of LRK on ER was not obvious. This study demonstrated that LRK exerted its therapeutic efficacy based on multi-components, multi-targets and multi-pathways. This research confirms the advantages of network pharmacology analyses and the necessity for experimental verification.

Animals

Multi-cohort integration and machine learning identify CPVL as a novel oncogenic driver in gastric cancer.

BACKGROUND: Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, and the prognosis of advanced GC remains poor. Systematic identification of robust biomarkers through multi-cohort integration and computational prioritization may facilitate the discovery of novel therapeutic targets. AIM: To identify key genes associated with gastric cancer progression through integrative multi-omics analysis and to elucidate the biological functions and molecular mechanisms of the top-prioritized candidate gene. METHODS: Comprehensive bioinformatics analyses integrating The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Gene Expression Omnibus (GEO) datasets were performed using differential expression analysis, weighted gene co-expression network analysis (WGCNA), Cox regression, and eight machine-learning algorithms to systematically identify and prioritize GC-associated hub genes. Among the identified candidates, CPVL was selected for further validation based on its diagnostic and prognostic performance. CPVL expression and clinical relevance were validated by independent datasets and immunohistochemistry. Lentiviral constructs were used to overexpress or silence CPVL in GC cell lines. Functional assays were performed, including CCK-8, colony formation, EdU incorporation, and flow cytometry, to assess cell proliferation and cell-cycle distribution. Western blotting and JAK2 inhibitor (AZD1480) rescue experiments were performed to elucidate the underlying mechanisms, and a nude mouse xenograft model was used to evaluate tumorigenicity in vivo. RESULTS: Multi-cohort screening identified five hub genes (CPVL, AADAC, BCAT1, CPXM1, and FBN1). Among them, CPVL exhibited the highest diagnostic accuracy (AUC = 0.895) and the strongest correlation with poor overall survival, and was therefore selected for mechanistic investigation. CPVL expression was markedly upregulated in GC tissues and cell lines. Functional assays demonstrated that CPVL promotes GC cell proliferation and accelerates G1/S-phase transition. Mechanistically, CPVL activated the JAK2/STAT3 signaling pathway, upregulating Cyclin D1 and CDK4 while downregulating p27. Treatment with the JAK2 inhibitor AZD1480 partially reversed these effects. In vivo, CPVL knockdown significantly inhibited tumor growth. CONCLUSION: Through systematic multi-cohort integration and machine-learning prioritization, CPVL was identified as a novel oncogenic driver in gastric cancer. CPVL promotes tumor growth via activation of the JAK2/STAT3 pathway and regulation of the Cyclin D1/CDK4/p27 axis, highlighting its potential as a diagnostic biomarker and therapeutic target.

Biomarker

Nrm1 is a bistable switch connecting cell cycle progression to transcriptional control.

Entry into the cell cycle requires activation of G1 cyclin-dependent kinases (CDKs) and the G1/S transcriptional program. In fission yeast, the MBF complex is the main transcription factor driving early cell-cycle gene expression. MBF-dependent transcription is activated in metaphase and repressed at the end of S phase by a feedback loop involving the cyclin Cig2 and co-repressors Nrm1 and Yox1. While replicative stress inactivates Yox1 via phosphorylation, the mechanism that activates MBF during an unperturbed cell cycle remains unclear. Here, we identify Nrm1 as the key target of cell cycle regulation in a two-step control mechanism. First, CDK1 phosphorylates Nrm1 in metaphase, leading to its release-along with Yox1-from chromatin. Second, unphosphorylated Nrm1, generated either by dephosphorylation or de novo synthesis, is degraded during anaphase, preventing its re-association with MBF until the end of the next S phase. Together, these parallel pathways create a precisely timed window of MBF activation, ensuring proper cell cycle progression and preserving genomic stability.

Schizosaccharomyces

Exploring the treatment of liver cancer with Gehua Hugan Gao based on bioinformatics, network pharmacology, and molecular docking.

Gehua Hugan Gao (GHHGG) is a traditional Chinese medicine paste that is chiefly used to treat liver cancer. However, the potential impact of GHHGG on liver cancer remains unclear. We explored how GHHGG treats liver cancer using bioinformatics, network pharmacology, and molecular docking. Network pharmacology included GHHGG active ingredients, predicted targets, predicted targets for liver cancer, and differential gene collection. A protein-protein interaction network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins database, and crucial targets were ranked according to their degree values. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses of liver cancer targets were followed by survival, differential analysis, and molecular docking. Venn diagrams show 123 predicted GHHGG targets for the treatment of hepatocellular carcinoma (HCC). Enrichment analysis showed that GHHGG treats HCC through multiple targets and pathways. We also found that estrogen receptor 1, cytochrome P450 3A4, cyclin-dependent kinase 4, type IIA topoisomerase, aurora kinase A, and cyclin E1 targets were closely associated with HCC development through survival and differential analyses. Molecular docking confirmed GHHGG's strong affinity for liver cancer targets. This study helps us understand GHHGG ingredients and targets for liver cancer treatment. To a certain extent, the molecular mechanism of GHHGG in the treatment of liver cancer has been elucidated, thus providing a theoretical basis.

Molecular Docking Simulation

Functional genetics of rice PISTILLATA genes reveals new roles and target genes in flowering time, female fertility, and parthenocarpy.

Floral organ identity is controlled largely by the combinatorial action of MADS domain homeotic transcription factors. Lodicules are specialized plant organs in cereals and grasses that are involved in floret opening and facilitate pollination and fertility in rice (Oryza sativa L.). To understand the mechanisms underlying the specification of the rice lodicule, we investigated the developmental functions of the rice PISTILLATA (PI) paralogs, OsMADS2, and OsMADS4. Null osmads2 mutants reiterated OsMADS2 nonredundant lodicule specification roles and revealed new roles in flowering time and floral organ number and fate. Doubly perturbed osmads2 osmads4kd florets had severe abnormalities, were female infertile, yet could initiate parthenocarpy. Ubiquitous OsMADS4 overexpression rescued osmads2 abnormalities. We also utilized genome-wide binding analyses and transcriptome profiling to identify putative target genes contributing to OsMADS2 functions. In osmads2d8/d8 null mutant, we observed deregulated genes in a plethora of processes including lodicule and stamen development, floral organ number, and cell wall development. Some examples are cell division regulators (Cyclin D6, Cyclin-P4-1-like), an aquaporin (PIP1A), a peptide transporter, a vascular developmental regulator (HOX1), and a cell wall modulator (GH9B16). The deregulation of these genes may be associated with the disrupted cell division, tissue differentiation, and physiology of the malformed lodicules in osmads2 and osmads2 osmads4kd florets. Altogether, we reveal novel roles for the rice PI paralogs in flowering time, panicle exsertion, and embryo sac differentiation, identify gene targets for lodicule development, and provide mechanistic insights on the functional diversification of rice PI paralogs.

Oryza

Establishment of Stable Immortalized Human Choroidal Melanocytes for Ocular Research.

PURPOSE: The short lifespan of primary normal choroidal melanocytes (NCMs) in vitro represents a major barrier to mechanistic, functional, and translational studies of choroid biology and uveal melanoma (UM). This study aimed to establish and characterize immortalized human NCM lines that retain melanocytic function, maintain a non-cancerous profile, and are amenable to gene editing. METHODS: NCMs from four donors were immortalized by lentiviral transduction of cyclin-dependent kinase 4 (CDK4R24C), cyclin D1, and human telomerase reverse transcriptase (hTERT), establishing NCM-K4DT lines. Their morphology, melanocytic marker expression, proliferation, and functional properties (melanin synthesis and tyrosinase activity) were evaluated. Genomic stability was assessed by targeted mutation profiling, karyotyping, and copy number variation (CNV) analysis. The tumorigenicity was tested in immunodeficient mice. Plasmid-based CRISPR/Cas9 editing was performed to determine their suitability for gene editing. RESULTS: NCM-K4DT lines retained dendritic-shaped morphology, pigmentation, and expression of PMEL, TYRP1, Melan-A, and SOX10. Cells exhibited enhanced proliferative capacity with preserved cell cycle regulation. Melanin production and tyrosinase activity were comparable to primary NCMs. Genomic profiling confirmed the absence of UM-associated driver mutations and chromosomal abnormalities. In vivo growth assays demonstrated that NCM-K4DT lines did not form tumors within the 3-month observation period. Notably, NCM-K4DT cells were efficiently edited by CRISPR/Cas9. CONCLUSIONS: NCM-K4DT lines represent stable, non-cancerous, and genetically tractable models for studying choroidal melanocyte biology, modeling UM-associated mechanisms, and advancing therapeutic development in ocular research.

Humans

Spatial Proteomic Profiling, a Novel Method for Detecting Diagnostic and Prognostic Proteins in Pediatric Sarcoma.

Pediatric sarcomas comprise approximately 10% of all childhood solid malignancies and are characterized by distinct genetic and proteomic alterations that have potential diagnostic, prognostic, and therapeutic significance. We have utilized digital spatial profiling (DSP) to identify protein expression in pediatric Ewing sarcoma (ES), Osteosarcoma (OS), Alveolar rhabdomyosarcoma (ARMS), and Embryonal rhabdomyosarcoma (ERMS), in association with clinical outcomes. Formalin-fixed, paraffin-embedded sections from a tissue microarray block containing eight ES, eight OS, five ARMS, and three ERMS cases were subjected to proteomic DSP on a GeoMx NanoString platform yielding information on expression of 580 proteins. Proteins related to epigenetic regulation, signaling pathways, and mesenchymal differentiation were broadly expressed across all tumor types. Tumor-specific protein profiles were defined based on highly expressed proteins. Differentially expressed proteins include Cyclin D1 in ES, S100A4 in OS and IKKi/IKKe in ARMS and ERMS. Immunohistochemical validation confirmed variable expression of H3K27me3 across the tumors, and elevated expression of Cyclin D1 in ES and S100 in OS. These findings underscore the utility of DSP as a high-resolution proteomic tool for the identification of clinically relevant biomarkers in pediatric sarcomas. The results provide a foundation for further investigation of candidate proteins with potential diagnostic, prognostic, and therapeutic applications.

Humans

A Genomic Alteration in GATA3 Affects Treatment Responses With a CDK4/6 Inhibitor Collaborating With p18INK4C Expression in Advanced Breast Carcinoma.

Cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) with endocrine therapy benefits patients with hormone receptor-positive, human epidermal growth receptor 2-negative breast carcinomas. However, most tumors develop resistance to CDK4/6i during the course of therapy. Although preclinical studies have proposed molecular mechanisms for the resistance, predictive markers are yet to be discovered. We investigated the tumor molecular profiling in 42 patients with advanced-stage breast carcinoma who received CDK4/6i therapy. The tumors carrying a GATA-binding protein 3 (GATA3) gene mutation, mainly a frameshift variant, showed a better treatment response compared with other tumors. Furthermore, we explored the potential underlying mechanism of this association. To that end, nuclear expression of p18, one of the INK family proteins, was found to be positively associated with the GATA3 mutation, as well as a CDK4/6i treatment response. Therefore, our study suggests that a GATA3 gene mutation, collaborating with p18 protein expression in tumor nuclei, may have a predictive value for CDK4/6i therapy in breast carcinoma.

Humans

RNF115 aggravates tumor progression through regulation of CDK10 degradation in thyroid carcinoma.

BACKGROUND: RING Finger Protein 115 (RNF115), a notable E3 ligase, is known to modulate tumorigenesis and metastasis. In our investigation, we endeavor to unravel the putative function and inherent mechanism through which RNF115 influences the evolution of thyroid carcinoma (THCA). METHODS: We analyzed RNF115 expression in THCA using the Cancer Genome Atlas (TCGA) database. The influence of RNF115 on the progression of THCA was evaluated using both in vitro and in vivo experimental approaches. The protein regulated by RNF115 was identified through bioinformatics analysis, and its biological significance was further explored. RESULTS: In both THCA tissues and cells, RNF115 showed elevated expression levels. Enhanced expression of RNF115 fostered cell proliferation, tumor growth, and the exacerbation of epithelial-mesenchymal transition (EMT) in THCA, while also promoting tumor lung metastasis. Bioinformatics analysis identified cyclin-dependent kinase 10 (CDK10) as a downstream target of RNF115, which was found to be ubiquitinated and degraded by RNF115 in THCA cells. Functionally, overexpression of CDK10 was found to counteract the promotion of malignant phenotype in THCA induced by RNF115. From a mechanistic perspective, RNF115 activated the Raf-1 pathway and enhanced cancer cell cycle progression by degrading CDK10 in THCA cells. CONCLUSION: RNF115 triggers cell proliferation, EMT, and tumor metastasis by ubiquitinating and degrading CDK10. The regulation of the Raf-1 pathway and cell cycle progression in THCA may be profoundly influenced by this process.

Humans

Impact of BRCA2 pathogenic variants on outcomes to first-line CDK4/6 inhibitors plus endocrine therapy in HR-positive/HER2-negative metastatic breast cancer.

BACKGROUND: Currently, three cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) are approved in combination with endocrine therapy (ET) as first-line treatment of patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC). The impact of homologous recombination repair (HRR) pathogenic variants (PV) on outcomes with first-line CDK4/6i plus ET in HR-positive/HER2-negative MBC remains uncertain. PATIENTS AND METHODS: We conducted a multicenter, real-world, case-control study including 233 patients with HR-positive/HER2-negative MBC treated with first-line CDK4/6i and ET. Among them, 116 presented HRR PVs and 117 were matched controls with negative germline testing. The primary objective was to compare progression-free survival (PFS) and overall survival among germline-BRCA2 PV carriers, other HRR PV carriers, and controls. To minimize baseline differences in prognostic factors between PV carriers and controls, inverse probability of treatment weighting was applied. Molecular analyses in pre-CDK4/6i samples among patients with BRCA2 PV were carried out, including RAD51-foci, PAM50 intrinsic subtype, and RB1 loss of heterozygosity (LOH). RESULTS: Among the included 233 patients, median age at diagnosis was 45 years (interquartile range 39-56) and 33% had de novo metastatic disease. Primary resistance to adjuvant ET was present in 10% and secondary resistance in 27%. After a median follow-up of 44 months, patients with germline-BRCA2 PVs (n = 67) had significantly shorter PFS [11 versus 27 months; adjusted hazard ratio (aHR) 2.73, 95% confidence interval (CI) 1.65-4.51, P < 0.001] compared with controls. Among patients with endocrine-sensitive disease, germline BRCA2 PV carriers had markedly shorter PFS (median PFS 12 versus 39 months; aHR 4.04; 95% CI 1.82-8.98, P < 0.001). Exploratory analyses revealed RB1 LOH before CDK4/6i-treatment in most evaluable BRCA2 tumors. CONCLUSIONS: BRCA2 PVs were independently associated with poorer outcomes to first-line CDK4/6i plus ET in HR-positive/HER2-negative MBC compared with controls, especially relevant among patients with endocrine-sensitive disease. These findings suggest that patients with a germline PV in BRCA2 may require alternative first-line strategies.

Humans

Inactivation of CDK12 Enhances Mitochondrial Efficiency to Suppress DNA Damage.

Inactivation of cyclin-dependent kinase 12 (CDK12) characterizes a subset of prostate cancers but it is not understood how cells adapt to declining activity of this major transcription elongation kinase. To probe this response, we developed a cell line resistant to an inhibitor targeting CDK12 and its paralog, CDK13. CDK13 can compensate for the loss of CDK12, which is why we used the dual inhibitor THZ531. Targeted drug screening of the parental and resistant cell lines revealed cross-resistance to other transcriptional kinases but no clear acquired point of vulnerability. Using genome-wide mapping of mRNA-stabilization based on metabolic labelling of RNA, we report selective mRNA stabilization of factors promoting oxidative phosphorylation in the resistant cells. We go on to show that loss of CDK12 activity enhances ATP production both in cell line models and in patient tumours. Finally, we show that dual inhibition of CDK12/13 results in excessive phosphorylation of the DNA damage H2AX in prostate cancer cells but not in our CDK12/13 inhibitor-resistant model system. In brief, we propose that inactivation of CDK12 rewires cellular energy metabolism to suppress DNA damage.

Humans

Skin-innervating glutamatergic neurons modulate aging.

Peripheral nerves regulate skin homeostasis by secreting neurotransmitters, but their role during skin aging remains incompletely understood. Here, we report that cutaneous denervation accelerates skin aging, as evidenced by collagen reduction. Neurofilament heavy chain (Nefh) is decreased in aged skin and is predominantly expressed in vesicular glutamate transporter 2-positive (Vglut2+) skin-innervating glutamatergic neurons. Notably, dermal fibroblasts, the primary producers of collagen, frequently contact Nefh+ nerve fibers. Moreover, Nefh deletion in Vglut2+ glutamatergic neurons drives skin fibroblast senescence and collagen loss, whereas additional glutamate improves skin aging phenotypes. Mechanistically, cyclin-dependent kinase 5 (Cdk5) interacts with both Nefh and Vglut2 and maintains glutamate release and collagen homeostasis. Additionally, in skin fibroblasts, solute carrier family 1 member 3 (Slc1a3) governs the collagen-promoting and anti-senescence functions of glutamate. Together, these findings reveal Nefh-mediated glutamatergic neuromodulation of skin aging and provide therapeutic targets for aging-related skin disorders.

Animals

CDK12 inhibition reveals melanoma dependence on the RUNX1/CBF&#x3b2; complex for genomic stability.

Cutaneous melanoma is the deadliest form of skin cancer, frequently driven by hyperactivation of the RAS/mitogen-activated protein kinase (MAPK) pathway. Cyclin-dependent kinase 12 (CDK12), a downstream effector of MAPK signaling, has emerged as a therapeutic target due to its essential role in transcriptional regulation and DNA damage repair. To identify vulnerabilities associated with CDK12 inhibition, we performed a genome-wide CRISPR-Cas9 screen and identified the Runt-related transcription factor RUNX1 and its cofactor CBF&#x3b2; as synthetic lethal partners of CDK12. RUNX1 inhibition enhanced melanoma sensitivity to CDK12 inhibitors in a p53-independent manner, resulting in DNA damage accumulation and impaired repair capacity. Combined inhibition of CDK12 and RUNX1 suppressed melanoma growth in vivo. These findings identify RUNX1/CBF&#x3b2; as a compensatory mechanism in CDK12-inhibited melanoma and define a synthetic lethal interaction with translational potential for combinatorial therapy.

Core Binding Factor Alpha 2 Subunit

Novel CDK-independent function of CDC25 phosphatases in mRNA translation.

Molecular and functional networks driving coordination between cell cycle and mRNA translation remain to be explored. Here, we use mass spectrometry-based proteomics to comprehensively investigate the interactome and phosphoproteome of the cell cycle regulator CDC25A. We identify actors of mRNA regulation, such as RNA-binding proteins and translation factors, as interacting partners of CDC25A. CDC25A overexpression increases global translation, whereas catalytic inactivation or pharmacological inhibition decreases protein synthesis. A Cyclin-Dependent Kinase (CDK) interaction-deficient mutant of CDC25A also enhances translation, indicating a CDK-independent role. Our results further reveal an interplay between CDC25A and CDC25B whereby downregulation of CDC25A leads to compensatory overexpression of CDC25B. The roles of CDC25A and CDC25B in mRNA translation are independent of their roles in the cell cycle, with CDC25A possibly regulating translation elongation and CDC25B rather involved in initiation. In acute myeloid leukemia cells, CDC25A depletion also inhibits translation, suggesting its potential relevance as a therapeutic target. We propose that CDC25 phosphatases might be signaling platforms coordinating cell cycle progression with protein synthesis.

cdc25 Phosphatases

scribble mutants cooperate with oncogenic Ras or Notch to cause neoplastic overgrowth in Drosophila.

Cancer is a multistep process involving cooperation between oncogenic or tumor suppressor mutations and interactions between the tumor and surrounding normal tissue. Here we present the first description of cooperative tumorigenesis in Drosophila, by using a system that mimics the development of tumors in mammals. We have used the MARCM system to generate mutant clones of the apical-basal cell polarity tumor suppressor gene, scribble, in the context of normal tissue. We show that scribble mutant clones in the eye disc exhibit ectopic expression of cyclin E and ectopic cell cycles, but do not overgrow due to increased cell death mediated by the JNK pathway and the surrounding wild-type tissue. In contrast, when oncogenic Ras or Notch is expressed within the scribble mutant clones, cell death is prevented and neoplastic tumors develop. This demonstrates, for the first time in Drosophila, that activated alleles of Ras and Notch can act as cooperating oncogenes in the development of epithelial tumors, and highlights the importance of epithelial polarity regulators in restraining oncogenes and preventing tumor formation.

Animals