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Query: UNIPROT:P10415 (
Bcl-2
)
33,771
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Biliary tract cancer, or cholangiocarcinoma, has a poor prognosis. Resection is the only curative treatment, but only a minority of patients are eligible. Chemotherapy and gamma-irradiation are merely palliative, as they are unable to remove the malignancy completely. The chicken anemia virus-derived protein apoptin induces apoptosis in a wide range of human tumor cells and is not hindered by mutations inactivating p53 or by overexpression of
Bcl-2
, changes known to frustrate chemotherapy and radiation therapy. We examined whether apoptin kills human biliary tract cancer cells. Expression of apoptin by means of plasmids caused extensive cell death in three independent cholangiocarcinoma cell lines, CC-LP, CC-SW, and Mz-ChA-1, regardless of their oncogenic mutations, which included inactivated p16 and p53 and the disruption of the transforming growth factor beta signaling pathway. In vitro delivery of apoptin by an adenoviral vector completely eradicated cholangiocarcinoma cells. Moreover, coexpression of the broad-spectrum caspase inhibitor
p35
with apoptin only delayed the induced cell death. Changes in nuclear morphology still occurred early after transfection, and nuclei eventually disintegrated, suggesting that apoptin-induced cell death in these cells is not blocked by mutations in either the initiation or execution phase of apoptosis. The efficient induction of cell death by apoptin in cholangiocarcinoma cell lines makes apoptin an attractive candidate for molecular therapy of biliary tract cancer.
...
PMID:The tumor-selective viral protein apoptin effectively kills human biliary tract cancer cells. 1464 20
Members of the
Bcl-2
family of proteins play important roles in the regulation of cell death by apoptosis. The yeast Two-Hybrid system was utilized to identify a protein that interacts with the anti-apoptotic protein
Bcl-2
, designated BMRP. This protein corresponds to a previously known mitochondrial ribosomal protein (MRPL41). Binding experiments confirmed the interaction of BMRP to
Bcl-2
in mammalian cells. Subcellular fractionation by differential centrifugation studies showed that both
Bcl-2
and BMRP are localized to the same fractions (fractions that are rich in mitochondria). Northern blot analysis revealed a major bmrp mRNA band of approximately 0.8 kb in several human tissues. Additionally, a larger 2.2 kb mRNA species was also observed in some tissues. Western blot analysis showed that endogenous BMRP runs as a band of 16-17 kDa in SDS-PAGE. Overexpression of BMRP induced cell death in primary embryonic fibroblasts and NIH/3T3 cells. Transfection of BMRP showed similar effects to those observed by overexpression of the pro-apoptotic proteins Bax or Bad. BMRP-stimulated cell death was counteracted by co-expression of
Bcl-2
. The baculoviral caspase inhibitor
p35
also protected cells from BMRP-induced cell death. These findings suggest that BMRP is a mitochondrial ribosomal protein involved in the regulation of cell death by apoptosis, probably affecting pathways mediated by
Bcl-2
and caspases.
...
PMID:BMRP is a Bcl-2 binding protein that induces apoptosis. 1554 50
Aberrant calpain activation is a key mediator of neuron death. We examined the cell-permeable calpain inhibitor MDL28170 in the pathophysiological processes after spinal cord injury (SCI) including
p35
-p25- cyclin-dependent kinase-5 (Cdk5) activation, tau hyperphosphorylation, neuron cell death, calpain I activation, astrogliosis, and microglia activation. Our study showed that intrathecal administration of MDL28170 improved neurologic dysfunction, prevented neuron loss, decreased the number of apoptotic cells, and abated astrogliosis and microglia activation 7 days after spinal cord hemisection in rats. Reverse transcription polymerase chain reaction demonstrated calpain inhibition significantly attenuated the ratio of proapoptotic Bax/anti-apoptotic
Bcl-2
mRNA in the lesion and penumbra after SCI. Calpain, the calcium-activated proteolytic enzyme, was found to digest
p35
to its truncated product, p25. Moreover, abnormal Cdk5 activation by p25 and subsequent tau hyperphosphorylation triggers pathologic events leading to neurodegeneration and neurofibrillary tangles. We found
p35
-p25-Cdk5 activation and tau hyperphosphorylation in SCI, and then we showed that intrathecal MDL28170 treatment could diminish
p35
truncation, and abrogate aberrant tau phosphorylation. Double labeling of calpain I and phosphorylated tau (AT8) in the same cells of spinal cord lesion further implicated pathogenesis of SCI. In conclusion, MDL28170 abated calpain I activation, inhibited apoptosis and neuron loss, quenched microglia and astrocyte activation, and significantly improved neurologic deficit one week after spinal cord hemisection. The neuroprotective mechanisms of calpain inhibitor in SCI could be attenuating upregulation of Bax/
Bcl-2
ratio, preventing
p35
truncation in the lesion and penumbra, and abrogating tau hyperphosphorylation.
...
PMID:Calpain inhibitor inhibits p35-p25-Cdk5 activation, decreases tau hyperphosphorylation, and improves neurological function after spinal cord hemisection in rats. 1571 81
The herpes simplex virus type 2 (HSV-2) protein ICP10PK has anti-apoptotic activity in virus-infected hippocampal cultures through activation of the Ras/Raf-1/MEK/ERK pathway. To exclude the possible contribution of other viral proteins to cell fate determination, we examined the survival of primary hippocampal cultures and neuronally differentiated PC12 cells transfected with ICP10PK from apoptosis caused by nerve growth factor (NGF) withdrawal. NGF deprivation caused apoptosis in cultures mock-transfected or transfected with the kinase-negative ICP10 mutant p139(TM), but not in ICP10PK-transfected cultures. In one clone (PC47), ICP10PK inhibited caspase-3 activation through up-regulation/stabilization of adenylate cyclase (AC), activation of PKA and MEK, and the convergence of the two pathways on extracellular signal-regulated kinase activation. The anti-apoptotic proteins Bag-1 and
Bcl-2
were stabilized and the pro-apoptotic protein Bad was phosphorylated (inactivated). In another clone (PC70), ICP10PK inhibited apoptosis through MEK-dependent up-regulation of the anti-apoptotic protein XIAP (that inhibits the activity of processed caspase-3) and down-regulation of the apoptogenic protein Smac/DIABLO. This may be cell-type specific, but the baculovirus
p35
protein did not potentiate the neuroprotective activity of ICP10PK in PC12 cells, suggesting that ICP10PK inhibits both caspase activation and activity. The data indicate that ICP10PK inhibits apoptosis independent of other viral proteins and is a promising neuronal gene therapy platform.
...
PMID:The herpes simplex virus type 2 gene ICP10PK protects from apoptosis caused by nerve growth factor deprivation through inhibition of caspase-3 activation and XIAP up-regulation. 1787 40
Although previous studies have indicated that the neuroprotective effect of N-acetylcysteine (NAC) required activation of the Ras-extracellular-signal-regulated kinase (ERK) pathway, the detailed mechanisms and signal cascades leading to activation ERK are not clear. In the present study, we investigated the effect of NAC on A beta(25-35)-induced neuronal death. Pretreatment of neurons with NAC 1 hr before application of A beta prevented A beta-mediated cell death. NAC increased cyclin-dependent kinase 5 (Cdk5) phosphorylation, an effect that was blocked by Cdk5 inhibitor. The neuroprotective effect of NAC was significantly attenuated by Cdk5 inhibitors or in neurons transfected with Cdk5 or
p35
small interfering RNA (siRNA). Conversely, pretreatment of neurons with the calpain inhibitors calpeptin or MDL28170 enhanced the neuroprotective effect of NAC. A beta(25-35) caused a significant decrease in the level of
p35
, with a concomitant increase in p25, which was completely prevented by NAC. This effect of NAC was blocked by the Cdk5 inhibitors roscovitine and butyrolactone. In addition, NAC increased Cdk5/
p35
kinase activity but reduced Cdk5 kinase activity. A beta(25-35) treatment decreased phosphorylated levels of ERK, which could be reversed by NAC. The effect of NAC was completely blocked by Cdk5 inhibitors. NAC reversed the A beta(25-35)-induced decrease in the expression of
Bcl-2
, which could be blocked by the MAPK kinase (MEK) inhibitor or Cdk5 inhibitors. These results suggest that NAC-mediated neuroprotection against A beta toxicity is likely mediated by the
p35
/Cdk5-ERKs-
Bcl-2
signal pathway.
...
PMID:N-acetylcysteine prevents beta-amyloid toxicity by a stimulatory effect on p35/cyclin-dependent kinase 5 activity in cultured cortical neurons. 1851 59
The mannosylated lipoarabinomanan (ManLAM) from mycobacterial species possesses strong anti-apoptotic action. Here we examined the ability of ManLAM isolated from Mycobacterium tuberculosis H37Rv to alter expression profiles of apoptosis-related genes in mouse macrophages infected with Mycobacterium bovis BCG Danish strain. ManLAM suppressed BCG-induced apoptosis and activities of caspase-1, -3, -8 and 9. Mouse Apoptosis Gene Array showed that ManLAM significantly down-regulated pro-apoptotic and proinflammatory genes: caspase-1, -3, -7, -8 and -9, TNF-alpha/TNFSF2, Fas/TNFRSF6, Bax-alpha, as well as IL-12
p35
and iNOS simultaneously up-regulating anti-apoptotic genes such as
Bcl-2
and Mcl-1. The effect of ManLAM was contrary to BCG-induced up-regulation of proapoptotic and pro-inflammatory genes and consistent with the functional data.
...
PMID:Gene expression profiling of lipoarabinomannan-treated mouse macrophage cultures infected with Mycobacterium bovis BCG. 1864
Cyclin-dependent kinase-5 is widely expressed and predominantly regulated by the non-cyclin activator
p35
. Since we recently showed that expression of
p35
in the kidney is restricted to podocytes, we examined here its function in mice in which
p35
was genetically deleted. The mice did not exhibit kidney abnormalities during glomerular development or during adult life. Conditionally immortalized cultured podocytes, derived from these null mice, did not have any change in their morphology, differentiation, or proliferation. However, when these cultured podocytes were exposed to UV-C irradiation, serum depletion, puromycin aminonucleoside, or transforming growth factor-beta-1, they showed increased apoptosis compared to those from wild-type mice. Levels of
Bcl-2
were decreased in these null podocytes but increased after transduction with human
p35
. Restoration of
p35
or the ectopic expression of
Bcl-2
reduced the susceptibility of
p35
-null podocytes to apoptosis. Experimental glomerulonephritis, characterized by podocyte apoptosis and subsequent crescent formation, was utilized to test these findings in vivo. Podocyte apoptosis was significantly increased in diseased
p35
-null compared with wild-type mice, accompanied by increased glomerulosclerosis and decreased renal function. Our study shows that
p35
does not affect glomerulogenesis but controls podocyte survival following injury, in part, by regulating
Bcl-2
expression.
...
PMID:p35, the non-cyclin activator of Cdk5, protects podocytes against apoptosis in vitro and in vivo. 2013 May 26
Cdk5 has long been recognized to play an important role in development, maturation and apoptosis of postmitotic and terminally differentiated cells. Activation of Cdk5 is tightly regulated by specific activators. Cyclin I was recently characterized as the first cyclin protein that binds to and activates Cdk5. Cyclin I-Cdk5 activates the MEK-ERK pathway and results in increased
Bcl-2
and Bcl-X(L) mRNA and protein levels. Lack of Cyclin I renders podocytes more susceptible to apoptosis. Interestingly, activation of Cdk5 by
p35
is also involved in the podocytes' response to injury. In the absence of
p35
, podocytes are more prone to undergo apoptosis. Here, we propose a new model where Cdk5 plays a central role in the cellular response machinery against injury-induced apoptosis of post-mitotic cells. While Cyclin I-Cdk5 regulates
Bcl-2
family proteins through activation of the MEK-ERK pathway,
p35
-Cdk5 directly phosphorylates and stabilizes
Bcl-2
.
...
PMID:Cyclin I-Cdk5 governs survival in post-mitotic cells. 2040 35
Cyclin-dependent kinase (Cdk)-5 is activated by both cyclin I and the noncyclin activator
p35
in terminally differentiated cells such as kidney podocytes and neurons. Cyclin I and
p35
are restricted to podocytes in the kidney, and each limit podocyte apoptosis by activating Cdk5. To determine whether both activators are necessary, or whether they serve backup roles, a double cyclin I-
p35
null mouse was generated. Experimental glomerular disease characterized by podocyte apoptosis was then induced by administering an anti-podocyte antibody. The results showed that under nonstressed conditions double mutants had normal kidney structure and function and were indistinguishable from wild-type, cyclin I(-/-), or
p35
(-/-) mice. In contrast, when stressed with disease, podocyte apoptosis increased fourfold compared with diseased cyclin I(-/-) or
p35
(-/-) mice. This resulted in a more pronounced decrease in podocyte number, proteinuria, and glomerulosclerosis. Under normal states and nephritic states, levels for the prosurvival protein
Bcl-2
were lower in double cyclin I(-/-)
p35
(-/-) mice than the other mice. Similarly, levels of Bcl-xL, another prosurvival member, were lower in normal and nephritic double cyclin I(-/-)
p35
(-/-) mice but similar to single-cyclin I(-/-) mice. Moreover, levels of ERK1/2 and MEK1/2 activation were lower in nephritic double cyclin I(-/-)
p35
(-/-) mice but similar to single-cyclin I(-/-) mice. The results demonstrate that the activators of Cdk5,
p35
, and cyclin I are not required for normal kidney function. However, they play pivotal coordinated roles in maintaining podocyte survival during stress states in disease.
...
PMID:Both cyclin I and p35 are required for maximal survival benefit of cyclin-dependent kinase 5 in kidney podocytes. 2226 81
Podocyte apoptosis contributes to the pathogenesis of diabetic nephropathy (DN). However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis remain poorly understood. Recent findings indicate that the disruption of the cytoskeleton is related to the podocyte apoptosis. In the present study, we investigated the involvement of nestin, an important cytoskeleton-associated class VI intermediate filament (IF) protein, in the high glucose (HG)-induced podocyte apoptosis. Our data showed that HG decreased the expression level of nestin, either mRNA or protein, in a time-dependent manner in cultured podocytes. Also, through knockdown of nestin expression by miRNA interference, the HG-induced podocyte apoptotic rate was significantly increased. The expression of cleaved caspase-3 was also markedly elevated. Considering that nestin is a substrate of cyclin-dependent kinase 5 (Cdk5), we further assessed the expression of Cdk5 in HG-treated podocytes. The results showed that HG stimulation increased the protein and mRNA expression of Cdk5 in a time-dependent manner in cultured mouse podocytes. The protein activator of Cdk5,
p35
, was also increased in a time-dependent manner by HG stimulation, and downregulation of Cdk5 by miRNA interference attenuated the nestin reduction in HG-treated podocytes; the HG-induced podocyte apoptosis, the increased cleaved caspase-3 expression and the Bax/
Bcl-2
ratio were all effectively attenuated. These data suggested that nestin, which is dependent on Cdk5 regulation, plays a cytoprotective role in HG-induced podocyte apoptosis.
...
PMID:Nestin protects mouse podocytes against high glucose-induced apoptosis by a Cdk5-dependent mechanism. 2261 21
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