• BAY 2402234
• aldolase
• anaerobic glycolysis
• cell cycle
• cyclin D1
• glyceraldehyde-3-phosphate dehydrogenase (GAPDH)
• liver regeneration
• palbociclib
• pentose phosphate pathway (PPP)
• purine
• pyrimidine

• Biosynthetic Pathways
• Cyclin D1/genetics
• Cyclin D1/metabolism
• Cyclin-Dependent Kinase 4/metabolism
• Hepatocytes/metabolism
• Proteomics
• Pyrimidines/biosynthesis
• Humans
• Animals
• Mice
• Cell Line

• P30 CA177558 NCI NIH HHS
• R01 DK054921 NIDDK NIH HHS

• EGFR
• GH signaling
• Intermittent GH
• Liver
• PCNA
• STAT

• cell cycle
• cell growth
• cell size
• cell size checkpoint
• cell size homeostasis
• cell size sensing
• target size

• E2F
• cell cycle
• cell growth
• cell size
• cyclin D
• growth factor signaling
• metabolism

• Animals
• Cell Cycle/genetics
• Cell Cycle/physiology
• Cell Cycle Proteins/genetics
• Cell Cycle Proteins/metabolism
• Cell Proliferation/genetics
• Cell Proliferation/physiology
• Cyclins/genetics
• Cyclins/metabolism
• DNA/metabolism
• DNA-Binding Proteins/genetics
• DNA-Binding Proteins/metabolism
• Mammals/genetics
• Saccharomyces cerevisiae/metabolism
• Transcription Factors/genetics
• Transcription Factors/metabolism

• R35 GM140900 NIGMS NIH HHS
• R35 GM140900 NIH HHS

• Cancer
• Cell biology
• Molecular biology

• R01 DK120330 NIDDK NIH HHS

• Liver
• MAFLD
• Metabolic dysfunction-associated fatty liver disease
• Mitogen-activated protein kinase
• Protein kinases
• Protein-protein interaction

• Disease Progression
• Humans
• Inflammation
• Non-alcoholic Fatty Liver Disease/metabolism
• Phosphatidylinositol 3-Kinases
• Protein Kinases

• cell signaling
• gender dimorphism
• kidney growth
• kidney transplantation
• ornithine decarboxylase

• E2F1
• TOR
• cell cycle
• translational control
• uORF

• R01 CA251928 NCI NIH HHS
• R01 DK125396 NIDDK NIH HHS

• (R)-PFI-2
• Cell cycle
• Doxorubicin
• Non-small cell lung cancer
• Set7/9 methyltransferase

• cell cycle
• glycogen
• liver regeneration
• partial hepatectomy
• pyruvate carboxylase

• 4EBP1
• Kp-10
• Rb/E2F1
• bMEC
• proliferation

• Carcinogenesis
• Epigenetics
• Kidney cancer
• Nicotine
• Oxidative tress
• Stem cell

• R01 AG055452 NIA NIH HHS
• R01 DK054921 NIDDK NIH HHS
• R01 DK114401 NIDDK NIH HHS

• chronic endometritis
• implantation loss
• lipopolysaccharide
• models

Aberrant activation of CDK4/6 kinase is the most common somatic event in non-small cell lung cancer (NSCLC). Palbociclib is a highly specific CDK4/6 inhibitor shown to inhibit cell cycle progression and promote cellular senescence. We conducted a phase 2 clinical trial of palbociclib in 19 previously-treated patients with advanced NSCLC. Only patients with p16-null staining by immunohistochemistry and documented tumor progression were eligible. The primary endpoint was tumor response rate. Palbociclib therapy alone was well-tolerated. Of 16 evaluable patients who received > 1 month of therapy, there were no objective responses. However, 8 patients (50%) with previously progressive NSCLC had stable disease (SD) lasting a range of 4-10.5 months. Median overall survival (OS) for all cases was 5.1 months, and median overall survival for the subset of patients with SD was 16.6 months. We also performed preclinical testing of palbociclib in combination with 13 different targeted or cytotoxic chemotherapeutic agents using a cell viability assay. Only the combination of palbociclib and mTOR inhibitors resulted in synergistic growth inhibition, particularly in tumors carrying RAS mutations. Our findings warrant further clinical investigation of the combination of palbociclib and mTOR inhibitors, especially in patients carrying activated RAS mutations.

• CDK 4/6
• clinical trial
• mTOR
• non-small cell lung cancer
• palbociclib

• dedifferentiation
• regeneration
• repair
• reprogramming
• transdifferentiation

• Acinar Cells
• Animals
• Autophagosomes/physiology
• Cell Cycle/physiology
• Cell Differentiation/physiology
• Cell Proliferation/physiology
• Cell Transdifferentiation/physiology
• Cellular Reprogramming/physiology
• Chief Cells, Gastric/pathology
• Gastrointestinal Tract/pathology
• Gene Expression
• Humans
• Lysosomes
• Mechanistic Target of Rapamycin Complex 1/metabolism
• Metaplasia/genetics
• Mice
• Mice, Inbred C57BL
• Regeneration/physiology
• S Phase/physiology
• SOX9 Transcription Factor/metabolism
• Stomach/injuries
• Stomach/pathology
• Transferases (Other Substituted Phosphate Groups)/genetics

• R01 DK094989 NIDDK NIH HHS
• R01 HL038180 NHLBI NIH HHS
• P30 CA091842 NCI NIH HHS
• R37 HL038180 NHLBI NIH HHS
• R01 DK110406 NIDDK NIH HHS
• R56 DK110406 NIDDK NIH HHS
• R01 DK112378 NIDDK NIH HHS
• R01 DK105129 NIDDK NIH HHS
• R01 DK056260 NIDDK NIH HHS
• T32 GM007067 NIGMS NIH HHS
• P30 DK052574 NIDDK NIH HHS

Cyclin D1 is a cell cycle protein that promotes proliferation by mediating progression through key checkpoints in G1 phase. It is also a proto-oncogene that is commonly overexpressed in human cancers. In addition to its canonical role in controlling cell cycle progression, cyclin D1 affects other aspects of cell physiology, in part through transcriptional regulation. In this study, we find that cyclin D1 inhibits the activity of a key metabolic transcription factor, peroxisome proliferator-activated receptor α (PPARα), a member of nuclear receptor family that induces fatty acid oxidation and may play an anti-neoplastic role. In primary hepatocytes, cyclin D1 inhibits PPARα transcriptional activity and target gene expression in a cdk4-independent manner. In liver and breast cancer cells, knockdown of cyclin D1 leads to increased PPARα transcriptional activity, expression of PPARα target genes, and fatty acid oxidation. Similarly, cyclin D1 depletion enhances binding of PPARα to target sequences by chromatin immunoprecipitation. In proliferating hepatocytes and regenerating liver in vivo, induction of endogenous cyclin D1 is associated with diminished PPARα activity. Cyclin D1 expression is both necessary and sufficient for growth factor-mediated repression of fatty acid oxidation in proliferating hepatocytes. These studies indicate that in addition to playing a pivotal role in cell cycle progression, cyclin D1 represses PPARα activity and inhibits fatty acid oxidation. Our findings establish a new link between cyclin D1 and metabolism in both tumor cells and physiologic hepatocyte proliferation.

• breast cancer
• hepatocellular carcinoma
• liver regeneration
• metabolism
• peroxisome proliferator-activated receptor alpha

• Associating liver partition with portal vein ligation for staged hepatectomy
• Liver regeneration
• Liver transection
• Portal vein embolization
• Portal vein ligation

• Animals
• Cell Proliferation
• Cytokines/metabolism
• Embolization, Therapeutic
• Hepatectomy/methods
• Hepatocytes/cytology
• Humans
• Ligation
• Liver/physiology
• Liver/surgery
• Liver Neoplasms/pathology
• Liver Regeneration
• Liver Transplantation/methods
• Mice
• Portal Vein/pathology
• Portal Vein/surgery
• Regeneration
• Vascular Surgical Procedures

• Ac-H3K9, histone H3 acetylated on lysine 9
• CDKI, cyclin dependent kinase inhibitor
• ChIP-Seq, chromatin immunoprecipitation-next generation DNA sequencing
• GO, gene ontology
• PH, partial hepatectomy
• SAHA, suberoylanilide hydroxamic acid
• TSS, transcription start sites
• Zn-HDAC, zinc-dependent histone deacetylase
• chromatin immunoprecipitation
• histone acetylation
• histone deacetylase
• partial hepatectomy
• qRT-PCR, semi-quantitative real-time reverse-transcription polymerase-chain-reaction
• suberoylanilide hydroxamic acid

The molecular mechanism underlying renal hypertrophy and progressive nephron damage remains poorly understood. Here we generated congenic ribosomal protein S6 (rpS6) knockin mice expressing non-phosphorylatable rpS6 and found that uninephrectomy-induced renal hypertrophy was significantly blunted in these knockin mice. Uninephrectomy-induced increases in cyclin D1 and decreases in cyclin E in the remaining kidney were attenuated in the knockin mice compared to their wild-type littermates. Uninephrectomy induced rpS6 phosphorylation in the wild type mice; however, no rpS6 phosphorylation was detected in uninephrectomized or sham-operated knockin mice. Nonetheless, uninephrectomy stimulated comparable 4E-BP1 phosphorylation in both knockin and wild type mice, indicating that mTORC1 was still activated in the knockin mice. Moreover, the mTORC1 inhibitor rapamycin prevented both rpS6 and 4E-BP1 phosphorylation, significantly blunted uninephrectomy-induced renal hypertrophy in wild type mice, but did not prevent residual renal hypertrophy despite inhibiting 4E-BP1 phosphorylation in uninephrectomized knockin mice. Thus, both genetic and pharmacological approaches unequivocally demonstrate that phosphorylated rpS6 is a downstream effector of the mTORC1-S6K1 signaling pathway mediating renal hypertrophy. Hence, rpS6 phosphorylation facilitates the increase in cyclin D1 and decrease in cyclin E1 that underlie the hypertrophic nature of uninephrectomy-induced kidney growth.

• DNA damage
• apoptosis
• autophagy
• cAMP response element-binding protein 1
• chemoresistance
• mechanistic target of rapamycin

AIM: To investigate the effects of mammalian target of rapamycin (mTOR) inhibition on liver regeneration and autophagy in a surgical resection model.

METHODS: C57BL/6 mice were subjected to a 70% partial hepatectomy (PH) and treated intraperitoneally every 24 h with a combination of the mTOR inhibitor rapamycin (2.5 mg/kg per day) and the steroid dexamethasone (2.0 mg/kg per day) in phosphate buffered saline (PBS) or with PBS alone as vehicle control. In the immunosuppressant group, part of the group was treated subcutaneously 4 h prior to and 24 h after PH with a combination of human recombinant interleukin 6 (IL-6; 500 μg/kg per day) and hepatocyte growth factor (HGF; 100 μg/kg per day) in PBS. Animals were sacrificed 2, 3 or 5 d after PH and liver tissue and blood were collected for further analysis. Immunohistochemical staining for 5-Bromo-2’-deoxyuridine (BrdU) was used to quantify hepatocyte proliferation. Western blotting was used to detect hepatic microtubule-associated protein 1 light chain 3 (LC3)-II protein expression as a marker for autophagy. Hepatic gene expression levels of proliferation-, inflammation- and angiogenesis-related genes were examined by real-time reverse transcription-polymerase chain reaction and serum bilirubin and transaminase levels were analyzed at the clinical chemical core facility of the Erasmus MC-University Medical Center.

RESULTS: mTOR inhibition significantly suppressed regeneration, shown by decreased hepatocyte proliferation (2% vs 12% BrdU positive hepatocyte nuclei at day 2, P < 0.01; 0.8% vs 1.4% at day 5, P = 0.02) and liver weight reconstitution (63% vs 76% of initial total liver weight at day 3, P = 0.04), and furthermore increased serum transaminase levels (aspartate aminotransferase 641 U/L vs 185 U/L at day 2, P = 0.02). Expression of the autophagy marker LC3-II, which was reduced during normal liver regeneration, increased after mTOR inhibition (46% increase at day 2, P = 0.04). Hepatic gene expression showed an increased inflammation-related response [tumor necrosis factor (TNF)-α 3.2-fold upregulation at day 2, P = 0.03; IL-1Ra 6.0-fold upregulation at day 2 and 42.3-fold upregulation at day 5, P < 0.01] and a reduced expression of cell cycle progression and angiogenesis-related factors (HGF 40% reduction at day 2; vascular endothelial growth factor receptor 2 50% reduction at days 2 and 5; angiopoietin 1 60% reduction at day 2, all P≤ 0.01). Treatment with the regeneration stimulating cytokine IL-6 and growth factor HGF could overcome the inhibitory effect on liver weight (75% of initial total liver weight at day 3, P = 0.02 vs immunosuppression alone and P = 0.90 vs controls) and partially reversed gene expression changes caused by rapamycin (TNF-α and IL-1Ra levels at day 2 were restored to control levels). However, no significant changes in hepatocyte proliferation, serum injury markers or autophagy were found.

CONCLUSION: mTOR inhibition severely impairs liver regeneration and increases autophagy after PH. These effects are partly reversed by stimulation of the IL-6 and HGF pathways.

• Hepatocyte proliferation
• Autophagy
• Microtubule-associated protein 1 light chain 3
• Partial hepatectomy
• Rapamycin

• Aminopyridines/pharmacology
• Analysis of Variance
• Antineoplastic Combined Chemotherapy Protocols
• Apoptosis/drug effects
• Autophagy/drug effects
• Camptothecin/administration & dosage
• Camptothecin/analogs & derivatives
• Camptothecin/pharmacology
• Carcinoma, Hepatocellular/drug therapy
• Cell Cycle/drug effects
• Cell Line
• Cell Respiration/drug effects
• Cisplatin/administration & dosage
• Cisplatin/pharmacology
• Doxorubicin/administration & dosage
• Doxorubicin/pharmacology
• Everolimus
• Humans
• Imidazoles/pharmacology
• Immunoblotting
• Immunohistochemistry
• In Situ Nick-End Labeling
• Irinotecan
• Liver Neoplasms/drug therapy
• Morpholines/pharmacology
• Phosphoinositide-3 Kinase Inhibitors
• Quinolines/pharmacology
• Sirolimus/analogs & derivatives
• Sirolimus/pharmacology
• TOR Serine-Threonine Kinases/antagonists & inhibitors

• GSK3β
• NFκB
• c-fos
• c-jun
• c-myc
• cyclin D1
• cyclin E
• growth hormone
• liver
• β-catenin

When the cell cycle is arrested, even though growth-promoting pathways such as mTOR are still active, then cells senesce. For example, induction of either p21 or p16 arrests the cell cycle without inhibiting mTOR, which, in turn, converts p21/p16-induced arrest into senescence (geroconversion). Here we show that geroconversion is accompanied by dramatic accumulation of cyclin D1 followed by cyclin E and replicative stress. When p21 was switched off, senescent cells (despite their loss of proliferative potential) progressed through S phase, and levels of cyclins D1 and E dropped. Most cells entered mitosis and then died, either during mitotic arrest or after mitotic slippage, or underwent endoreduplication. Next, we investigated whether inhibition of mTOR would prevent accumulation of cyclins and loss of mitotic competence in p21-arrested cells. Both nutlin-3, which inhibits mTOR in these cells, and rapamycin suppressed geroconversion during p21-induced arrest, decelerated accumulation of cyclins D1 and E and decreased replicative stress. When p21 was switched off, cells successfully progressed through both S phase and mitosis. Also, senescent mouse embryonic fibroblasts (MEFs) overexpressed cyclin D1. After release from cell cycle arrest, senescent MEFs entered S phase but could not undergo mitosis and did not proliferate. We conclude that cellular senescence is characterized by futile hyper-mitogenic drive associated with mTOR-dependent mitotic incompetence.

The traditional Chinese medicine component dehydrocostuslactone (DHC) isolated from Saussurea costus (Falc.) Lipschitz, has been shown to have anti-cancer activity. Angiogenesis is an essential process in the growth and progression of cancer. In this study, we demonstrated, for the first time, the anti-angiogenic mechanism of action of DHC to be via the induction of cell cycle progression at the G0/G1 phase due to abrogation of the Akt/glycogen synthase kinase-3β (GSK-3β)/cyclin D1 and mTOR signaling pathway. First, we demonstrated that DHC has an anti-angiogenic effect in the matrigel-plug nude mice model and an inhibitory effect on human umbilical vein endothelial cell (HUVEC) proliferation and capillary-like tube formation in vitro. DHC caused G0/G1 cell cycle arrest, which was associated with the down-regulation of cyclin D1 expression, leading to the suppression of retinoblastoma protein phosphorylation and subsequent inhibition of cyclin A and cdk2 expression. With respect to the molecular mechanisms underlying the DHC-induced cyclin D1 down-regulation, this study demonstrated that DHC significantly inhibits Akt expression, resulting in the suppression of GSK-3β phosphorylation and mTOR expression. These effects are capable of regulating cyclin D1 degradation, but they were significantly reversed by constitutively active myristoylated (myr)-Akt. Furthermore, the abrogation of tube formation induced by DHC was also reversed by overexpression of Akt. And the co-treatment with LiCl and DHC significantly reversed the growth inhibition induced by DHC. Taken together, our study has identified Akt/GSK-3β and mTOR as important targets of DHC and has thus highlighted its potential application in angiogenesis-related diseases, such as cancer.

• Angiogenesis
• bioenergetics
• everolimus

• Animals
• Antibiotics, Antineoplastic/pharmacology
• Cell Cycle/drug effects
• Cell Cycle/physiology
• Cell Proliferation/drug effects
• Cells, Cultured
• Cyclin D1/genetics
• Cyclin D1/metabolism
• Genotype
• Hepatectomy
• Hepatocytes/cytology
• Hepatocytes/physiology
• Isoenzymes/genetics
• Isoenzymes/metabolism
• Liver/cytology
• Liver/drug effects
• Liver/physiology
• Liver Regeneration/physiology
• Mechanistic Target of Rapamycin Complex 1
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Multiprotein Complexes
• Proteins/metabolism
• Ribosomal Protein S6 Kinases, 90-kDa/genetics
• Ribosomal Protein S6 Kinases, 90-kDa/metabolism
• Sirolimus/pharmacology
• TOR Serine-Threonine Kinases

• R01 DK054921 NIDDK NIH HHS
• DK54921 NIDDK NIH HHS

The branched-chain amino acid (BCAA) leucine has been identified to be a key regulator of skeletal muscle anabolism. Activation of anabolic signalling occurs via the mammalian target of rapamycin (mTOR) through an undefined mechanism. System A and L solute carriers transport essential amino acids across plasma membranes; however it remains unknown whether an exogenous supply of leucine regulates their gene expression. The aim of the present study was to investigate the effects of acute and chronic leucine stimulation of anabolic signalling and specific amino acid transporters, using cultured primary human skeletal muscle cells.

Human myotubes were treated with leucine, insulin or co-treated with leucine and insulin for 30 min, 3 h or 24 h. Activation of mTOR signalling kinases were examined, together with putative nutrient sensor human vacuolar protein sorting 34 (hVps34) and gene expression of selected amino acid transporters. Phosphorylation of mTOR and p70S6K was transiently increased following leucine exposure, independently to insulin. hVps34 protein expression was also significantly increased. However, genes encoding amino acid transporters were differentially regulated by insulin and not leucine.

mTOR signalling is transiently activated by leucine within human myotubes independently of insulin stimulation. While this occurred in the absence of changes in gene expression of amino acid transporters, protein expression of hVps34 increased.

• cyclin d1b
• liver regeneration
• steroid 5-α reductase
• 17β-hydroxysteroid dehydrogenase
• 3β-hydroxysteroid dehydrogenase