CDK4 promotes beta cell differentiation
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ABSTRACT:
PROVIDER: PRJNA984652 | ENA |
REPOSITORIES: ENA
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Project description:Expanding beta cell mass is a critical goal in the fight against diabetes. CDK4, an extensively characterized cell cycle activator, is required to establish and maintain beta cell number. Beta cell failure in the IRS2-deletion mouse type 2 diabetes model is in part due to loss of CDK4 regulator Cyclin D2. We set out to determine whether replacement of endogenous CDK4 with the inhibitor-resistant mutant CDK4-R24C rescued the loss of beta cell mass in Irs2-deficient mice. Surprisingly, not only beta cell mass but also beta cell dedifferentiation was effectively rescued, despite no improvement in whole body insulin sensitivity. Ex vivo studies in primary islet cells revealed a novel mechanism in which CDK4 intervened downstream in the insulin signaling pathway to prevent FOXO1-mediated transcriptional repression of critical beta cell transcription factor Pdx1. FOXO1 inhibition was not related to E2F1 activity, to FOXO1 phosphorylation, or even to FOXO1 subcellular localization, but rather was related to deacetylation and reduced FOXO1 abundance. Taken together, these results demonstrate a novel differentiation-promoting activity of the classical cell cycle activator CDK4 and support the concept that beta cell mass can be expanded without compromising function.
2023-07-31 | GSE235129 | GEO
Project description:Inhibition of CDK4/6 Promotes CD8 T cell memory
| PRJNA734381 | ENA
Project description:Inhibition of CDK4/6 Promotes CD8 T cell memory
| PRJNA734380 | ENA
Project description:Beta cell directed differentiation (ChIP-seq)
| PRJEB2707 | ENA
Project description:The molecular chaperons FK506-binding proteins (Fkbps) comprise one of three families of peptidyl prolyl isomerases, which promote the transition between cis- and trans-conformations of peptidyl prolyl bonds. Mouse Fkbp family is composed of at least 15 members, but the functions of the large family in cell proliferation and differentiation remain elusive. During myoblast differentiation, the cells need to exit the cell cycle before fusion and terminal differentiation to form myotubes. The clear distinction between proliferation and differentiation provides an ideal model with which to investigate the roles of Fkbps in these two cell biological events. We found that depletion of FkbpC in mouse myoblasts delayed the exit from the cell cycle and expression of myotube-specific genes, whereas its overexpression caused opposite effects. At a mechanistic level, our study revealed a crucial function of FkbpC in Cdk4 activation during myoblast proliferation. Cdk4 undergoes conformational changes in the HSP90/Cdc37/Cdk4 complex as a prerequisite for activation through binding to CyclinD1 accompanied by phosphorylation. Our results showed that FkbpC depletion released Cdk4 from the HSP90 complex, which increased the Cdk4/CyclinD1 complex in myoblasts and sustained high levels of phosphorylated Cdk4 and Rb during differentiation. These results explain the delayed cell cycle exit and differentiation in the depleted cells. In addition, after synchronizing the cell cycle of myoblasts we found dynamic changes of the amounts of FkbpC and Cdk4 in the HSP90 complex during the G1/S transition. Knockout mice of FkbpC demonstrated delayed muscle regeneration after chemical damage, providing an in vivo evidence for the essential role of FkbpC in muscle differentiation. Collectively, our study uncovered FkbpC's critical function as a novel switch regulating the transition from proliferation to differentiation through controlling one of the central regulators of proliferation, Cdk4.
2018-11-27 | GSE109237 | GEO
Project description:Pharmacologicalinhibitors of cyclin dependent kinases 4 and 6 (CDK4/6) are an approvedtreatment forhormone receptor-positive breast cancer and are currently under evaluation across hundreds of clinical trials for other cancertypes. The clinical success of these inhibitorsis largely attributedto well-defined tumor-intrinsic cytostatic mechanisms, while their emerging role as immunomodulatory agents is lessunderstood. Usingintegrated epigenomic, transcriptomic and proteomicanalyses, we demonstrateda novel action of CDK4/6inhibitorsin promoting the phenotypic and functional acquisition of immunological T cell memory.Short-term priming with a CDK4/6inhibitorpromoted long-termendogenousanti-tumor T cell immunityin mice, enhanced the persistence and therapeutic efficacy of chimeric antigen receptor (CAR)-T cells, and induced an RB-dependent T cell phenotype supportive offavorable responses to immune checkpoint blockade in melanoma patients.Together, thesemechanistic insights significantlybroaden the prospective utility of CDK4/6 inhibitors as clinical tools to boostanti-tumorT cell immunity.
2021-06-08 | PXD026539 | Pride
Project description:Cell size and the cell cycle are intrinsically coupled and abnormal increases in cell size are associated with senescence and permanent cell cycle arrest. The mechanism by which overgrowth primes cells to withdraw from the cell cycle remains unknown. We investigate this here using CDK4/6 inhibitors that arrest cell cycle progression during G0/G1 and are used in the clinic to treat ER+/HER2- metastatic breast cancer. We demonstrate that CDK4/6 inhibition promotes cellular overgrowth during G0/G1, causing p38MAPK-p53-p21-dependent cell cycle withdrawal. We find that cell cycle withdrawal is triggered by two waves of p21 induction. First, overgrowth during a long-term G0/G1 arrest induces an osmotic stress response. This stress response produces the first wave of p21 induction. Second, when CDK4/6 inhibitors are removed, a fraction of cells escape long term G0/G1 arrest and enter S-phase where overgrowth-driven replication stress results in a second wave of p21 induction that causes cell cycle withdrawal from G2, or the subsequent G1. We propose a model whereby both waves of p21 induction contribute to promote permanent cell cycle arrest. This model could explain why cellular hypertrophy is associated with senescence and why CDK4/6 inhibitors have long-lasting effects in patients.
2023-11-27 | PXD036519 | Pride
Project description:Coiled-coil domain-containing 68 (CCDC68) plays different roles in cancer and is predicted as a tumor suppressor in human colorectal cancer (CRC). However, the specific role of CCDC68 in CRC and the underlying mechanisms remain unknown. Here, we showed that CCDC68 expression was lower in CRC than in corresponding normal tissues, and CCDC68 level was positively correlated with disease-free survival. Ectopic expression of CCDC68 decreased CRC cell proliferation in vitro and suppressed the growth of CRC xenograft tumors in vivo. CCDC68 caused G0/G1 cell cycle arrest, downregulated CDK4, and upregulated ITCH, the E3 ubiquitin ligase responsible for CDK4 protein degradation. This increased CDK4 degradation, which decreased CDK4 protein levels and inhibited CRC tumor growth. Collectively, the present results identify a novel CDK4 regulatory axis consisting of CCDC68 and ITCH, which suggest that CCDC68 is a promising target for the treatment of CRC.
2021-04-14 | PXD024343 | Pride
Project description:Genomic aberrations of Cyclin D1 (CCND1) and CDK4 in neuroblastoma indicate that dysregulation of the G1 entry checkpoint is an important cell cycle aberration in this pediatric tumor. Here we report that analysis of Affymetrix expression data of primary neuroblastic tumors shows an extensive over-expression of Cyclin D1 and CDK4 which correlates with histological subgroups and prognosis respectively. Immunohistochemical analysis demonstrated an over-expression of Cyclin D1 in neuroblasts and a low Cyclin D1 expression in all cell types in ganglioneuroma. This suggests an involvement of G1 regulating genes in neuronal differentiation processes which we further evaluated using RNA interference against Cyclin D1 and its kinase partner CDK4 in several neuroblastoma cell lines. This resulted in pRb pathway inhibition as shown by an almost complete disappearance of CDK4 specific pRb phosphorylation; reduction of E2F transcriptional activity and a decrease of Cyclin A protein levels. The Cyclin D1 and CDK4 knock-down resulted in a significant reduction in cell proliferation, a G1 specific cell cycle arrest and moreover an extensive neuronal differentiation. Affymetrix microarray profiling of siRNA treated cells revealed a shift in expression profile towards a neuronal phenotype. Several new potential downstream players are identified. We conclude that neuroblastoma functionally depend on over-expression of G1 regulating genes to maintain their undifferentiated phenotype. Experiment Overall Design: The Cell line IMR-32 at time point 0 and transiently transfected with siRNA against GFP, Cyclin D1 and CDK4 at time point 48 hours. All experiments are biological triplicates.
2008-10-25 | E-GEOD-8866 | biostudies-arrayexpress
Project description:Charting in vitro beta cell differentiation by single cell RNA sequencing
| PRJNA471420 | ENA