Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MDM2 is a critical negative regulator of the p53 tumor suppressor protein. Recently, small-molecule antagonists of MDM2, the Nutlins, have been developed to inhibit the p53-MDM2 interaction and activate p53 signaling. However, half of human cancers have mutated p53 and they are resistant to Nutlin treatment. Here, we report that treatment of the p53-mutant malignant peripheral nerve sheath (MPNST) and p53-null HCT116 cells with cisplatin (Cis) and Nutlin-3a induced a degree of apoptosis that was significantly greater than either drug alone. Nutlin-3a also increased the cytotoxicity of both carboplatin and doxorubicin in a series of p53-mutant human tumor cell lines. In the human dedifferentiated liposarcoma cell line (LS141) and the p53 wild-type HCT116 cells, Nutlin-3a induced downregulation of E2F1 and this effect appeared to be proteasome dependent. In contrast, in MPNST and HCTp53-/- cells, Nutlin-3a inhibited the binding of E2F1 to MDM2 and induced transcriptional activation of free E2F1 in the presence of Cis-induced DNA damage. Downregulation of E2F1 by small interfering RNA significantly decreased the level of apoptosis induced by Cis and Nutlin-3a treatment. Moreover, expression of a dominant-negative form of E2F1 rescued cells from apoptosis, whereas cells overexpressing wild-type E2F1 showed an increase in cell death. This correlated with the induction of the proapoptotic proteins p73alpha and Noxa, which are both regulated by E2F1. These results indicate that antagonism of MDM2 by Nutlin-3a in cells with mutant p53 enhances chemosensitivity in an E2F1-dependent manner. Nutlin-3a therefore may provide a therapeutic benefit in tumors with mutant p53 provided it is combined with chemotherapy.
 ...
PMID:Mouse double minute antagonist Nutlin-3a enhances chemotherapy-induced apoptosis in cancer cells with mutant p53 by activating E2F1. 1714 34

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder caused by loss of motor neurons both in the brain and spinal cord, which dramatically reduces life expectancy. ALS occurs either in familial ALS or, more frequently, in sporadic ALS forms. Several mechanisms have been postulated to underlie motor neuron death. In the present paper, starting from some of the genes related to familial ALS, we overview and discuss their potential role in modifying of the physiological clearance of altered proteins and organelles in motor neurons. Special emphasis is placed on the role of autophagy, which seems to prevail as a protein clearing system over other multienzymatic pathways such as the proteasome within motor neurons. The evidence which links an altered autophagy to the onset of motor neuron death proposes that this biochemical pathway might represent a final common mechanism underlying both inherited and sporadic forms of ALS. In light of these findings we also analyze the potential significance of a novel association between ALS, altered autophagy, and mutations of nuclear proteins such as TAR-DNA-Binding Protein 43 and fused in sarcoma/translated in liposarcoma. Such an association appears to be critical since it is now well demonstrated that all sporadic and most familiar forms of ALS are characterized by altered deposition and mislocalization of TAR-DNA-Binding Protein 43. These novel insights into the pathogenesis of ALS may lead to the identification of novel strategies to promote motor neuron survival.
 ...
PMID:The role of autophagy: what can be learned from the genetic forms of amyotrophic lateral sclerosis. 2040 84

Liposarcoma is the most common soft tissue sarcoma with a high risk of relapse. Few therapeutic options are available for the aggressive local or metastatic disease. Here, we report that the clinically used proteasome inhibitor bortezomib exhibits significantly stronger cytotoxicity toward highly malignant human liposarcoma SW872-S cells compared with its parental SW872 cells, which is accompanied by enhanced activation of apoptotic signaling both in vitro and in vivo. Treatment of cells with Jun-N-terminal kinase (JNK) inhibitor SP60015 or the translation inhibitor cycloheximide ameliorated this enhanced apoptosis. Bortezomib inhibited MDR1 expression and function more effectively in SW872-S cells than in SW872 cells, indicating that the increased cytotoxicity relies on the degree of proteasome inhibition. Furthermore, the pharmacological or genetic inhibition of sarco/endoplasmic reticulum calcium-ATPase (SERCA) 2, which is highly expressed in SW872-S cells, resulted in partial reversal of cell growth inhibition and increase of MDR1 expression in bortezomib-treated SW872-S cells. These results show that bortezomib exhibits preferential cytotoxicity toward SW872-S cells possibly via highly expressed SERCA2-associated MDR1 suppression and suggest that bortezomib may serve as a potent agent for treating advanced liposarcoma.
...
PMID:Preferential cytotoxicity of bortezomib toward highly malignant human liposarcoma cells via suppression of MDR1 expression and function. 2557 94