• CP: Molecular biology
• CP: Neuroscience
• HAFOUS
• Hao-Fountain syndrome
• Ppil4
• RNA splicing
• TMT proteomics
• USP7
• brain development
• deubiquitinase
• p53
• synapse
• ubiquitin

• Animals
• Ubiquitin-Specific Peptidase 7/metabolism
• Ubiquitin-Specific Peptidase 7/genetics
• Tumor Suppressor Protein p53/metabolism
• Signal Transduction
• Mice
• Neurons/metabolism
• Brain/metabolism
• Brain/pathology
• Mice, Knockout
• Ubiquitin/metabolism
• Dendritic Spines/metabolism
• Humans
• Synapses/metabolism

• R01 NS111014 NINDS NIH HHS
• R01 GM067945 NIGMS NIH HHS
• S10 OD021629 NIH HHS
• R01 NS051255 NINDS NIH HHS
• R01 GM132129 NIGMS NIH HHS

• Cancer
• Cell cycle
• Cell cycle inhibitors
• Drug repurposing
• Neurodegenerative disorders

• Humans
• Neurodegenerative Diseases/drug therapy
• Neurodegenerative Diseases/metabolism
• Neoplasms/drug therapy
• Neoplasms/pathology
• Neoplasms/metabolism
• Drug Repositioning
• Animals
• Cell Cycle/drug effects
• Signal Transduction/drug effects

• P50 HD103525 NICHD NIH HHS
• R01 GM132129 NIGMS NIH HHS
• R01 NS111014 NINDS NIH HHS

• NSC-34
• cannabinoids
• cannabinol
• cell cycle
• transcriptomic analysis

• Current Research Funds 2024 Ministero della Salute

• bioinformatics
• phosphorylation
• regulatory networks
• cellular signalling networks

• Humans
• CDC2 Protein Kinase/genetics
• CDC2 Protein Kinase/metabolism
• Protein Serine-Threonine Kinases/genetics
• Genes, cdc
• Cell Cycle
• Cell Division

• 21815 Associazione Italiana per la Ricerca sul Cancro (Italian Association for Cancer Research)

• Alzheimer's disease
• Apoptosis
• Bcl-2
• Caspase
• Drugs

• SH-SY5Y cells
• glutamate excitotoxicity
• neurodegeneration
• neuropeptide Y
• neuroprotection
• oxidative stress
• tunicamycin-induced ER stress

• Humans
• Neuroprotective Agents/pharmacology
• Neuropeptide Y/pharmacology
• Neuroblastoma
• Glutamic Acid/toxicity
• Tunicamycin/pharmacology
• Cell Line, Tumor

Sensory hair cell death caused by the ototoxic side effects of many clinically used drugs leads to permanent sensorineural hearing loss in patients. Aminoglycoside antibiotics are widely used and well-known for their ototoxicity, but the molecular mechanisms of aminoglycoside-induced hair cell death are not well understood. This creates challenges in our attempts to alleviate or prevent such adverse side effects. Here, we report a regulatory role of CDK2 in aminoglycoside-induced hair cell death. Utilizing organotypic cultures of cochleae from neonatal mice, we show that blocking CDK2 activity by either pharmaceutical inhibition or by Cdk2 gene knockout protects hair cells against the ototoxicity of gentamicin—one of the most commonly used aminoglycoside antibiotics—by interfering with intrinsic programmed cell death processes. Specifically, we show that CDK2 inhibition delays the collapse of mitochondria and the activation of a caspase cascade. Furthermore, at the molecular level, inhibition of CDK2 activity influences proapoptotic JNK signaling by reducing the protein level of c-Jun and suppressing the gentamicin-induced upregulation of c-Jun target genes Jun and Bim. Our in vivo studies reveal that Cdk2 gene knockout animals are significantly less sensitive to gentamicin ototoxicity compared to wild-type littermates. Altogether, our work ascertains the non-cell cycle role of CDK2 in regulating aminoglycoside-induced hair cell apoptosis and sheds lights on new potential strategies for hearing protection against ototoxicity.

• National Institute on Deafness and Other Communication Disorders

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease. Aberrant production and aggregation of amyloid beta (Aβ) peptide into plaques is a frequent feature of AD, but therapeutic approaches targeting Aβ accumulation fail to inhibit disease progression. The approved cholinesterase inhibitor drugs are symptomatic treatments. During human brain development, the progenitor cells differentiate into neurons and switch to a postmitotic state. However, cell cycle re-entry often precedes loss of neurons. We developed mathematical models of multiple routes leading to cell cycle re-entry in neurons that incorporate the crosstalk between cell cycle, neuronal, and apoptotic signaling mechanisms. We show that the integration of multiple feedback loops influences disease severity making the switch to pathological state irreversible. We observe that the transcriptional changes associated with this transition are also characteristics of the AD brain. We propose that targeting multiple arms of the feedback loop may bring about disease-modifying effects in AD.

•

Developed mathematical models of cell cycle re-entry in Alzheimer's disease (AD)

• Bioinformatics
• Biological sciences
• Neuroscience
• Systems biology
• Systems neuroscience

Caspases are a family of cysteine proteases that predominantly cleave their substrates after aspartic acid residues. Much of what we know of caspases emerged from investigation a highly conserved form of programmed cell death called apoptosis. This form of cell death is regulated by several caspases, including caspase-2, caspase-3, caspase-7, caspase-8 and caspase-9. However, these “killer” apoptotic caspases have emerged as versatile enzymes that play key roles in a wide range of non-apoptotic processes. Much of what we understand about these non-apoptotic roles is built on work investigating how “killer” caspases control a range of neuronal cell behaviors. This review will attempt to provide an up to date synopsis of these roles.

• H2020 Marie Skłodowska-Curie Actions

• airway epithelial cells
• apoptosis
• cell cycle
• house dust mite allergen
• hyperplastic mucous cells
• kinase
• phosphorylation
• resolution

• biomarkers
• eRNA regulatory network
• multi-omics bioinformatics analysis
• spinal cord injury
• therapeutic targets

• ASM
• BCL-2/BCL-xL
• ER–mitochondria
• apigenin
• cyclin B1–CDK1
• lipid raft
• oxidative stress

• Adult
• CDC2 Protein Kinase/physiology
• Cell Line, Tumor
• Cyclin B1/physiology
• Endoplasmic Reticulum/metabolism
• Endoplasmic Reticulum/pathology
• Female
• Humans
• Male
• Middle Aged
• Mitochondria/metabolism
• Mitochondria/pathology
• Nasopharyngeal Carcinoma/metabolism
• Oxidative Stress

• neural stem cells
• neurogenesis
• signaling dynamics
• β-catenin

• Activating Transcription Factor 3/metabolism
• Animals
• Apoptosis/physiology
• Brain/cytology
• Brain/metabolism
• Cell Cycle Checkpoints
• Cell Differentiation/physiology
• Cell Proliferation/physiology
• HEK293 Cells
• Hippocampus/cytology
• Hippocampus/metabolism
• Humans
• Intracellular Signaling Peptides and Proteins/metabolism
• Neural Stem Cells/cytology
• Neural Stem Cells/metabolism
• Neurogenesis/physiology
• Neurons/cytology
• Neurons/metabolism
• Primary Cell Culture
• Rats
• Signal Transduction
• Wnt Signaling Pathway
• beta Catenin/metabolism
• GADD45 Proteins

• R01 NS087253 NINDS NIH HHS
• R35 GM138211 NIGMS NIH HHS

Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor BNIP3L/Nix is responsive to lipotoxicity and accumulates in response to a high-fat (HF) feeding. To provide a better understanding of this observation, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the reported roles of these phospholipids and BNIP3L in mitochondrial dynamics, we investigated aberrant mitochondrial turnover as a mechanism of impaired myocyte insulin signaling. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that BNIP3L accumulation triggers mitochondrial depolarization, calcium-dependent activation of DNM1L/DRP1, and mitophagy. In addition, BNIP3L can inhibit insulin signaling through activation of MTOR-RPS6KB/p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and RHEB. Finally, we demonstrate that BNIP3L-induced mitophagy and impaired glucose uptake can be reversed by direct phosphorylation of BNIP3L by PRKA/PKA, leading to the translocation of BNIP3L from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of BNIP3L, mitochondrial turnover, and impaired myocyte insulin signaling during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggest a mechanism by which exercise or pharmacological activation of PRKA may overcome myocyte insulin resistance.

Abbreviations: BCL2: B cell leukemia/lymphoma 2; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; DNM1L/DRP1: dynamin 1-like; FUNDC1: FUN14 domain containing 1; IRS1: insulin receptor substrate 1; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; MFN1: mitofusin 1; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; OPA1: OPA1 mitochondrial dynamin like GTPase; PDE4i: phosphodiesterase 4 inhibitor; PLD1: phospholipase D1; PLD6: phospholipase D family member 6; PRKA/PKA: protein kinase, AMP-activated; PRKCD/PKCδ: protein kinase C, delta; PRKCQ/PKCθ: protein kinase C, theta; RHEB: Ras homolog enriched in brain; RPS6KB/p70S6K: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; YWHAB/14-3-3β: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein beta

• Insulin signaling
• MTOR
• Nix
• PKA
• mitochondria
• mitophagy
• muscle

Cell cycle dysregulation has been implicated in the pathogenesis of neurodegenerative disorders. Specialised function obligates neuronal cells to subsist in a quiescent state of cell cycle once differentiated and therefore the circumstances and mechanisms underlying aberrant cell cycle activation in post-mitotic neurons in physiological and disease conditions remains an intriguing area of research. There is a strict requirement of concurrence to cell cycle regulation for neurons to ensure intracellular biochemical conformity as well as interrelationship with other cells within neural tissues. This review deliberates on various mechanisms underlying cell cycle regulation in neuronal cells and underscores potential implications of their non-compliance in neural pathology. Recent research suggests that successful duplication of genetic material without subsequent induction of mitosis induces inherent molecular flaws that eventually assert as apoptotic changes. The consequences of anomalous cell cycle activation and subsequent apoptosis are demonstrated by the increased presence of molecular stress response and apoptotic markers. This review delineates cell cycle events under normal physiological conditions and deficits amalgamated by alterations in protein levels and signalling pathways associated with cell-division are analysed. Cell cycle regulators essentially, cyclins, CDKs, cip/kip family of inhibitors, caspases, bax and p53 have been identified to be involved in impaired cell cycle regulation and associated with neural pathology. The pharmacological modulators of cell cycle that are shown to impart protection in various animal models of neurological deficits are summarised. Greater understanding of the molecular mechanisms that are indispensable to cell cycle regulation in neurons in health and disease conditions will facilitate targeted drug development for neuroprotection.

• Apoptosis
• CDK
• Cell cycle
• Cyclin
• Neurodegeneration
• Neuron

• Alzheimer’s disease
• LMTK2
• digital image analysis
• neurodegeneration
• tau

• ÚNKP-19-3, ÚNKP-19-2 Hungarian Ministry of Innovation and Technologies, New National Excellence Program
• EFOP-3.6.3-VEKOP-16-2017-00009 EMBERI ERŐFORRÁS FEJLESZTÉSI OPERATÍV PROGRAM (EFOP)
• GINOP-2.3.2-15-2016-00043 Gazdaságfejlesztési és Innovációs Operatív Program (GINOP)
• 2017-1.2.1-NKP-2017-00002 Hungarian Brain Research Program
• 5S 567 (A202) SZTE ÁOK-KKA

• APC/C
• Cdk1
• Centriole
• Differentiation
• Mitosis
• Motile cilia
• Multiciliated cells

• CDK
• Cell cycle
• Metabolism
• Mitochondria
• Tumor resistance

Neurodegenerative disorders are frequent, incurable diseases characterised by abnormal protein accumulation and progressive neuronal loss. Despite their growing prevalence, the underlying pathomechanism remains unclear. Lemur tyrosine kinase 2 (LMTK2) is a member of a transmembrane serine/threonine-protein kinase family. Although it was described more than a decade ago, our knowledge on LMTK2’s biological functions is still insufficient. Recent evidence has suggested that LMTK2 is implicated in neurodegeneration. After reviewing the literature, we identified three LMTK2-mediated mechanisms which may contribute to neurodegenerative processes: disrupted axonal transport, tau hyperphosphorylation and enhanced apoptosis. Moreover, LMTK2 gene expression is decreased in an Alzheimer’s disease mouse model. According to these features, LMTK2 might be a promising therapeutic target in near future. However, further investigations are required to clarify the exact biological functions of this unique protein.

• Alzheimer’s disease
• Axonal transport
• LMTK2
• Neurodegeneration
• Tau

Cell cycle proteins are mainly expressed by dividing cells. However, it is well established that these molecules play additional non-canonical activities in several cell death contexts. Increasing evidence shows expression of cell cycle regulating proteins in post-mitotic cells, including mature neurons, following neuronal insult. Several cyclin-dependent kinases (Cdks) have already been shown to mediate ischemic neuronal death but Cdk1, a major cell cycle G2/M regulator, has not been investigated in this context. We therefore examined the role of Cdk1 in neuronal cell death following cerebral ischemia, using both in vitro and in vivo genetic and pharmacological approaches. Exposure of primary cortical neurons cultures to 4 h of oxygen–glucose deprivation (OGD) resulted in neuronal cell death and induced Cdk1 expression. Neurons from Cdk1-cKO mice showed partial resistance to OGD-induced neuronal cell death. Addition of R-roscovitine to the culture medium conferred neuroprotection against OGD-induced neuronal death. Transient 1-h occlusion of the cerebral artery (MCAO) also leads to Cdk1 expression and activation. Cdk1-cKO mice displayed partial resistance to transient 1-h MCAO. Moreover, systemic delivery of R-roscovitine was neuroprotective following transient 1-h MCAO. This study demonstrates that promising neuroprotective therapies can be considered through inhibition of the cell cycle machinery and particularly through pharmacological inhibition of Cdk1.

• Apoptosis
• BAD phosphorylation
• Bcl-2 family
• kinase inhibitor

• AZD1775
• Apoptosis
• CDK1
• CDK2
• Cytarabine
• DNA damage
• Leukemia
• WEE1

• Animals
• Apoptosis
• Humans
• Mitochondria/metabolism
• Mitochondrial Membranes/metabolism
• Mitosis
• Permeability
• Proto-Oncogene Proteins c-bcl-2/metabolism

• 088785/Z/09/Z Wellcome Trust

• PRAJA
• apoptosis
• glioblastoma

• P01 CA130821 NCI NIH HHS
• R01 AA023146 NIAAA NIH HHS
• R01 CA106614 NCI NIH HHS
• I01 BX003732 BLRD VA
• R01 DK056111 NIDDK NIH HHS
• R01 CA042857 NCI NIH HHS

The retinoblastoma protein (Rb), which typically functions as a transcriptional repressor of E2F‐regulated genes, represents a major control hub of the cell cycle. Here, we show that loss of the Arabidopsis Rb homolog RETINOBLASTOMA‐RELATED 1 (RBR1) leads to cell death, especially upon exposure to genotoxic drugs such as the environmental toxin aluminum. While cell death can be suppressed by reduced cell‐proliferation rates, rbr1 mutant cells exhibit elevated levels of DNA lesions, indicating a direct role of RBR1 in the DNA‐damage response (DDR). Consistent with its role as a transcriptional repressor, we find that RBR1 directly binds to and represses key DDR genes such as RADIATION SENSITIVE 51 (RAD51), leaving it unclear why rbr1 mutants are hypersensitive to DNA damage. However, we find that RBR1 is also required for RAD51 localization to DNA lesions. We further show that RBR1 is itself targeted to DNA break sites in a CDKB1 activity‐dependent manner and partially co‐localizes with RAD51 at damage sites. Taken together, these results implicate RBR1 in the assembly of DNA‐bound repair complexes, in addition to its canonical function as a transcriptional regulator.

• Arabidopsis
• DNA‐damage response
• RAD51
• retinoblastoma

• DNA damage
• DNA damage response
• DNA repair defects
• Neurodegeneration

• Apoptosis
• Colorectal cancer
• Proliferation
• UBAP2L
• siRNA

Neurons are usually regarded as postmitotic cells that undergo apoptosis in response to cell cycle reactivation. Nevertheless, recent evidence indicates the existence of a defined developmental program that induces DNA replication in specific populations of neurons, which remain in a tetraploid state for the rest of their adult life. Similarly, de novo neuronal tetraploidization has also been described in the adult brain as an early hallmark of neurodegeneration. The aim of this review is to integrate these recent developments in the context of cell cycle regulation and apoptotic cell death in neurons. We conclude that a variety of mechanisms exists in neuronal cells for G1/S and G2/M checkpoint regulation. These mechanisms, which are connected with the apoptotic machinery, can be modulated by environmental signals and the neuronal phenotype itself, thus resulting in a variety of outcomes ranging from cell death at the G1/S checkpoint to full proliferation of differentiated neurons.

• AD, Alzheimer disease
• BDNF, brain-derived neurotrophic factor
• BrdU, 5-bromo-2′-deoxyuridine
• CKI, Cdk-inhibitor
• CNS, central nervous system
• Cdk, cyclin-dependent kinase
• Cip/Kip, cyclin inhibitor protein/kinase inhibitor protein
• G0, quiescent state
• G1, growth phase 1
• G2, growth phase 2
• Ink, inhibitor of kinase
• Mcm2, minichromosome maintenance 2
• PCNA, proliferating cell nuclear antigen
• PD, Parkinson disease
• RGCs, retinal ganglion cells
• Rb, Retinoblastoma
• S-phase
• S-phase, synthesis phase.
• apoptosis
• cell cycle re-entry
• mitosis
• neuron
• p38MAPK, p38 mitogen-activated protein kinase
• p75NTR, neurotrophin receptor p75
• tetraploid

15,16-Dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge which is a functional food in Asia. In this study, we investigated the apoptotic effect of DHTS on the human acute myeloid leukemia (AML) type III HL-60 cell line. We found that treatment with 1.5 μg/mL DHTS increased proapoptotic Bax and Bad protein expressions and activated caspases-3, -8, and -9, thus leading to poly ADP ribose polymerase (PARP) cleavage and resulting in cell apoptosis. DHTS induced sustained c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. The anti-Fas blocking antibody reversed the DHTS-induced cell death, and the JNK-specific inhibitor, SP600125, inhibited DHTS-induced caspase-3, -8, -9, and PARP cleavage. In a xenograft nude mice model, 25 mg/kg DHTS showed a great effect in attenuating HL-60 tumor growth. Taken together, these results suggest that DHTS can induce HL-60 cell apoptosis in vitro and inhibit HL-60 cell growth in vivo; the underlying mechanisms might be mediated through activation of the JNK and FasL signal pathways.

• 15,16-dihydrotanshinone I
• Fas ligand
• acute myeloid leukemia
• apoptosis
• c-Jun N-terminal kinase

• Animals
• Antineoplastic Agents, Phytogenic/chemistry
• Antineoplastic Agents, Phytogenic/isolation & purification
• Antineoplastic Agents, Phytogenic/therapeutic use
• Apoptosis/drug effects
• Fas Ligand Protein/metabolism
• Functional Food/analysis
• Furans
• HL-60 Cells
• Humans
• JNK Mitogen-Activated Protein Kinases/metabolism
• Leukemia/drug therapy
• Leukemia/metabolism
• Leukemia/pathology
• Male
• Mice, Inbred BALB C
• Mice, Nude
• Phenanthrenes/chemistry
• Phenanthrenes/isolation & purification
• Phenanthrenes/therapeutic use
• Quinones
• Salvia miltiorrhiza/chemistry

• FOXO3a
• HDAC2
• oxidative stress
• p21
• transcription

• S phase kinase-associated protein 2
• cyclin B1
• diabetic nephropathy
• mitotic arrest deficiency 2B
• podocytes

• Animals
• Axons/metabolism
• Cells, Cultured
• Cerebellum/cytology
• Cerebellum/enzymology
• Cerebellum/growth & development
• Dendrites/metabolism
• Morphogenesis
• Rats
• Signal Transduction
• Ubiquitin/metabolism
• Ubiquitin-Specific Proteases/genetics
• Ubiquitin-Specific Proteases/metabolism

• NS051255 NINDS NIH HHS

Dysregulation of protein synthesis is emerging as a major contributory factor in cancer development. eIF3D (eukaryotic translation initiation factor 3 subunit D) is one member of the eIF3 (eukaryotic translation initiation factor 3) family, which is essential for initiation of protein synthesis in eukaryotic cells. Acquaintance with eIF3D is little since it has been identified as a dispensable subunit of eIF3 complex. Recently, eIF3D was found to embed somatic mutations in human colorectal cancers, indicating its importance for tumour progression. To further probe into its action in colon cancer, we utilized lentivirus-mediated RNA interference to knock down eIF3D expression in one colon cancer cell line HCT116. Knockdown of eIF3D in HCT116 cells significantly inhibited cell proliferation and colony formation in vitro. Flow cytometry analysis indicated that depletion of eIF3D led to cell-cycle arrest in the G2/M phase, and induced an excess accumulation of HCT116 cells in the sub-G1 phase representing apoptotic cells. Signalling pathways responsible for cell growth and apoptosis have also been found altered after eIF3D silencing, such as AMPKα (AMP-activated protein kinase alpha), Bad, PRAS40 [proline-rich Akt (PKB) substrate of 40 kDa], SAPK (stress-activated protein kinase)/JNK (c-Jun N-terminal kinase), GSK3β and PARP [poly(ADP-ribose) polymerase]. Taken together, these findings suggest that eIF3D might play an important role in colon cancer progression.

eIF3D is essential for colon cancer cell growth, and knockdown of eIF3D resulted in a significant reduction in cell proliferation probably due to activation of AMPKα, Bad, PRAS40, SAPK/JNK and GSK3β, as well as cleavage of PARP.

Human embryonic stem cells (hESC) and induced pluripotent stem cells (hiPSC) are characterised by an unusual and tightly regulated cell cycle that has been shown to be important for the maintenance of a pluripotent phenotype. Cyclin-dependant kinase 1 (CDK1) is a key player in cell cycle regulation and particularly mitosis; however, its role has not been studied previously in hESC and hiPSC. To investigate the impacts of CDK1 downregulation, we performed RNA interference studies which in addition to expected mitotic deficiencies revealed a large range of additional phenotypes related to maintenance of pluripotency, ability to repair double strand breaks (DSBs) and commitment to apoptosis. Downregulation of CDK1 led to the loss of typical pluripotent stem cell morphology, downregulation of pluripotency markers and upregulation of a large number of differentiation markers. In addition, human pluripotent stem cells with reduced CDK1 expression accumulated a higher number of DSBs were unable to activate CHK2 expression and could not maintain G2/M arrest upon exposure to ionising radiation. CDK1 downregulation led to the accumulation of cells with abnormal numbers of mitotic organelles, multiple chromosomal abnormalities and polyploidy. Furthermore, such cells demonstrated an inability to execute apoptosis under normal culture conditions, despite a significant increase in the expression of active PARP1, resulting in tolerance and very likely further propagation of genomic instabilities and ensuing of differentiation process. On the contrary, apoptosis but not differentiation, was the preferred route for such cells when they were subjected to ionising radiation. Together these data suggest that CDK1 regulates multiple events in human pluripotent stem cells ranging from regulation of mitosis, G2/M checkpoint maintenance, execution of apoptosis, maintenance of pluripotency and genomic stability.

Microtubules are a highly validated target in cancer therapy. However, the clinical development of tubulin binding agents (TBA) has been hampered by toxicity and chemoresistance issues and has necessitated the search for new TBAs. Here, we report the identification of a novel cell permeable, tubulin-destabilizing molecule - 4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid [1p-tolyl-meth-(E)-ylidene]-hydrazide (termed as Suprafenacine, SRF). SRF, identified by in silico screening of annotated chemical libraries, was shown to bind microtubules at the colchicine-binding site and inhibit polymerization. This led to G₂/M cell cycle arrest and cell death via a mitochondria-mediated apoptotic pathway. Cell death was preceded by loss of mitochondrial membrane potential, JNK - mediated phosphorylation of Bcl-2 and Bad, and activation of caspase-3. Intriguingly, SRF was found to selectively inhibit cancer cell proliferation and was effective against drug-resistant cancer cells by virtue of its ability to bypass the multidrug resistance transporter P-glycoprotein. Taken together, our results suggest that SRF has potential as a chemotherapeutic agent for cancer treatment and provides an alternate scaffold for the development of improved anti-cancer agents.

• Amino Acid Sequence
• Animals
• Antineoplastic Agents/chemistry
• Antineoplastic Agents/isolation & purification
• Antineoplastic Agents/pharmacology
• Apoptosis
• Binding Sites
• Colchicine/pharmacology
• G2 Phase Cell Cycle Checkpoints
• HeLa Cells
• Humans
• Hydrazines/chemistry
• Hydrazines/isolation & purification
• Hydrazines/pharmacology
• Indazoles/chemistry
• Indazoles/isolation & purification
• Indazoles/pharmacology
• Membrane Potential, Mitochondrial
• Mice
• Microtubules/chemistry
• Microtubules/drug effects
• Microtubules/metabolism
• Molecular Sequence Data
• PC12 Cells
• Protein Binding
• Rats
• Small Molecule Libraries/chemistry
• Small Molecule Libraries/pharmacology

• NMDA receptor
• PP1/PP2A
• cerebellar granule neurons
• dendrite
• phosphorylation
• transcription factor Sp4

Diabetic encephalopathy may lead to cognitive deficits in diabetic patients and diminish quality of life. It has been shown that protracted hyperglycaemia is directly associated with neuronal apoptosis, which is involved in diabetic encephalopathy. The anaphase-promoting complex (APC) is essential for the survival of post-mitotic neurons. In our previous study, we found that the mitotic arrest deficient protein MAD2B, one of APC inhibitors, was expressed in neurons in central nervous system. However, whether MAD2B is involved in hyperglycaemia-induced apoptosis and thus takes part in diabetic encephalopathy is still unknown. To address this issue, we first explored the expression of MAD2B and cyclin B1 detected by immunofluorescence and Western blot. It was found that hyperglycaemia remarkably increased the expression of MAD2B and accumulation of cyclin B1 in cortices of diabetes mellitus rat model and in cultured primary neurons. To further explore the role of MAD2B in hyperglycaemia-induced neuronal injury, we depleted MAD2B expression by a specifically targeted shRNA against MAD2B. We observed that MAD2B deficiency alleviated cyclin B1 expression and apoptotic neuronal death. These results demonstrate that MAD2B expression is the main culprit for accumulation of cyclin B1 and apoptosis in neurons under high glucose. Moreover, inhibition of the expression of MAD2B prevented neurons from entering an aberrant S phase that led differentiated neurons into apoptotic cell death. These results suggest that hyperglycaemia induced neuronal apoptosis through inducing expression of MAD2B, which represents a novel mechanism of diabetic encephalopathy.

• MAD2B
• cyclin B1
• hyperglycaemia
• neuronal injury