Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The question of specificity and the elucidation of the exact molecular mechanism of action of post-transcriptional gene silencing agents are two major challenges for their establishment as therapeutics. A proteomic off-target effect study (2-DE with MS) in combination with DIGE comparing the phosphorothioate antisense oligonucleotide oblimersen (Genasense, G3139) to a Bcl-2-targeting siRNA-sequence on human melanoma cells showed that additional off-target effects contribute to the apoptotic effect of oblimersen. When both oligonucleotides were transfected with lipofectamine 2000, only oblimersen increased apoptosis as determined by annexin staining and caspase activity measurement. In contrast to the highly specific siRNA, the expression level of a number of proteins was found to be altered after oblimersen treatment. Several proteins linked to apoptosis and stress response, among those galectin-1, cofilin-1, GRP78, HSP60, nucleophosmin, and peroxiredoxins, were identified and found to be down-regulated after oblimersen treatment. A down-regulation of enolase-1 and three other glycolytic enzymes indicates a reversion of the cancer-related Warburg effect. The observed effects may be caused by a phosphorothioate mediated blockage of the mitochondrial voltage dependent anion channel (VDAC).
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PMID:A proteomic study reveals unspecific apoptosis induction and reduction of glycolytic enzymes by the phosphorothioate antisense oligonucleotide oblimersen in human melanoma cells. 1952 45

A multi-inlet microfluidic hydrodynamic focusing (MF) system to prepare lipopolyplex (LP) containing Bcl-2 antisense deoxyoligonucleotide (ODN) was developed and evaluated. The lipopolyplex nanoparticles consist of ODN:protamine:lipids (1:0.3:12.5wt/wt ratio) and the lipids included DC-Chol:egg PC:PEG-DSPE (40:58:2mol/mol%). Using K562 human erythroleukemia cells, which contain an abundance of Bcl-2 and overexpression of transferrin receptors (TfR), and G3139 (oblimerson sodium or Genasense(TM)) as a model cell line and drug, respectively, the Bcl-2 down-regulation at the mRNA and protein levels as well as cellular uptake and apoptosis was compared between the conventional bulk mixing (BM) method and the MF method. The lipopolyplex size and surface charge were characterized by dynamic light scattering (DLS) and zeta potential (zeta) measurement, respectively, while the ODN encapsulation efficiency was determined by gel electrophoresis. Cryogenic transmission electron microscopy (Cryo-TEM) was used to determine the morphology of LPs. Our results demonstrated that MF produced LP nanoparticles had similar structures but smaller size and size distribution compared to BM LP nanoparticles. MF LP nanoparticles had higher level of Bcl-2 antisense uptake and showed more efficient down-regulation of Bcl-2 protein level than BM LP nanoparticles.
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PMID:Delivery of antisense oligodeoxyribonucleotide lipopolyplex nanoparticles assembled by microfluidic hydrodynamic focusing. 1971 52

The serum level of lactate dehydrogenase (LDH) is an important predictor of prognosis and treatment response in melanoma patients. It is unknown whether the expression of LDH-5 in tissue sections also has prognostic significance and whether it is related to the expression of the anti-apoptotic proteins, Bcl-2, Bcl-XL and Mcl-1, and endoplasmic reticulum stress protein glucose-regulated protein 78 (GRP78). Identification of an association between LDH-5 expression and anti-apoptotic proteins may have important therapeutic implications for melanoma patients. Sections from 159 pigmented lesions, including nevi and melanoma at different stages of progression were studied by immunohistochemistry. Correlation of LDH-5 expression with clinicopathological factors and with the expression of Bcl-2, Bcl-XL, Mcl-1 and GRP78 was examined. LDH-5 was detected at low levels in 6 of 10 compound nevi (60%) and 6 of 10 dysplastic nevi (60%). The percentage of positive cases was greater in thin (<or=1.0 mm) (74%) and thick primary melanoma (>1.0 mm) (95%) and in metastatic melanoma in the skin (100%) and lymph node (81%). The immunoreactive score was highly related to progression of melanoma (P<0.0001). LDH-5 expression was positively associated with increasing tumor thickness (P=0.02) and dermal tumor mitotic rate (P=0.02). LDH-5 above the median immunoreactive score was associated with reduced disease-free survival and overall survival (P<0.02). LDH-5 expression was negatively associated with Bcl-2 expression. In contrast, LDH-5 expression was strongly associated with Bcl-XL and Mcl-1 expression and also positively associated with GRP78 expression (P<0.0001). The low Bcl-2 expression in melanomas with high LDH-5 expression provides an explanation for the poor response of patients with high serum LDH levels to treatment with the Bcl-2 antisense drug 'Genasense'. The strong correlation of LDH-5 expression with Mcl-1 expression suggests that treatment strategies inhibiting the activity of Mcl-1 in melanoma patients should be investigated.
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PMID:Lactate dehydrogenase 5 expression in melanoma increases with disease progression and is associated with expression of Bcl-XL and Mcl-1, but not Bcl-2 proteins. 1983 63

Phosphorothioate antisense oligonucleotides have been widely used in clinical studies for rational sequence-specific gene silencing. However, several sequence-unspecific off-target effects have been recently described for this compound class. In contrast to siRNA-mediated knockdown of the same gene, the bcl-2-targeted oblimersen (Genasense, G3139) downregulates a number of proteins involved in apoptotic resistance and several glycolytic enzymes in 607B human melanoma cells. Regardless of their target, phosphorothioate-modified antisense and siRNA compounds, but not oligonucleotides with a phosphodiester backbone, resulted in a similar impact on the proteome. Unspecifically downregulated proteins include cancer markers involved in apoptotic resistance and endoplasmatic reticulum (ER) stress such as the 78 kDa glucose regulated protein (GRP 78), protein disulfide isomerase A3 (PDIA3, GRP 58), calumenin, and galectin-1, as well as the glycolytic enzymes triose phosphate isomerase, glyceraldehyde phosphodehydrogenase, and phosphoglycerate mutase. The depletion of the glycolytic enzymes is reflected by a decrease in L-lactate production, indicating a partial reversal of the Warburg effect. Compared with other phosphorothioate oligonucleotides, oblimersen generally led to a more pronounced effect both in terms of the number of influenced proteins and the extent of downregulation, suggesting a synergistic effect of Bcl-2 downregulation.
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PMID:Off-target effects related to the phosphorothioate modification of nucleic acids. 2054 86


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