Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P10415 (Bcl-2)
33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tumor suppressor gene MMAC/PTEN located on chromosome10q23.3 has dual phosphatase activity in the phosphoinositide-3-kinase signaling pathway and inhibits Akt activation, a serine-threonine kinase, which is involved in proliferative and antiapoptotic pathways. Furthermore, MMAC/PTEN is frequently inactivated in a variety of tumors including prostate cancer. In this study, we generated a new type of gene transfer drug, GelaTen, which is a microsphere of cationized gelatin hydrogels incorporating PTEN plasmid DNA. Using our previously reported radiation-resistant PC3-Bcl-2 human prostate cancer cells (PTEN deleted), we examined the efficacy of GelaTen to force the expression of PTEN in vivo to inhibit tumor growth after intratumoral injection alone or with irradiation. Combinational therapy with GelaTen and irradiation improved both the in vitro and in vivo efficacy of growth inhibition compared with GelaTen or irradiation alone. These data show that GelaTen gene therapy, enabling radiosensitization, can potentially treat prostate cancers that have MMAC/PTEN gene alterations associated with radioresistance.
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PMID:Delivery of PTEN via a novel gene microcapsule sensitizes prostate cancer cells to irradiation. 1864 98

Thyroid hormone (T3) plays a crucial role in processes such as cell proliferation and differentiation, whereas its implication on cellular apoptosis has not been well documented. Here we examined the effect of T3 on the apoptosis of GH4C1 pituitary cells and the mechanisms underlying this effect. We show that T3 produced a significant increase in apoptosis in serum-depleted conditions. This effect was accompanied by a decrease in nuclear factor-kappaB (NF-kappaB)-dependent transcription, IkappaBalpha phosphorylation, translocation of p65/NF-kappaB to the nucleus, phosphorylation, and transactivation. Moreover, these effects were correlated with a T3-induced decrease in the expression of antiapoptotic gene products, such as members of the inhibitor of apoptosis protein and Bcl-2 families. On the other hand, ERK but not c-Jun N-terminal kinase or MAPK p38, was activated upon exposure to T3, and inhibition of ERK alone abrogated T3-mediated apoptosis. In addition, T3 increased the expression of the MAPK phosphatase, dual specificity phosphatase 1 (DUSP1), in an ERK-dependent manner. Interestingly, the suppression of DUSP1 expression abrogated T3-induced inhibition of NF-kappaB-dependent transcription and p65/NF-kappaB translocation to the nucleus, as well as T3-mediated apoptosis. Overall, our results indicate that T3 induces apoptosis in rat pituitary tumor cells by down-regulating NF-kappaB activity through a mechanism dependent on the ERK/DUSP1 pathway.
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PMID:Thyroid hormone-mediated activation of the ERK/dual specificity phosphatase 1 pathway augments the apoptosis of GH4C1 cells by down-regulating nuclear factor-kappaB activity. 1875 55

Alzheimer's disease (AD) is a terminal age-associated dementia characterized by early synaptic dysfunction and late neurodegeneration. Although the presence of plaques of fibrillar aggregates of the amyloid beta peptide (Abeta) is a signature of AD, evidence suggests that the preplaque small oligomeric Abeta promotes both synaptic dysfunction and neuronal death. We found that young Tg2576 transgenic mice, which accumulate Abeta and develop cognitive impairments prior to plaque deposition, have high central nervous system (CNS) activity of calcineurin (CaN), a phosphatase involved in negative regulation of memory function via inactivation of the transcription factor cAMP responsive element binding proteins (CREB), and display CaN-dependent memory deficits. These results thus suggested the involvement of prefibrillary forms of Abeta. To investigate this issue, we compared the effect of monomeric, oligomeric, and fibrillar Abeta on CaN activity, CaN-dependent pCREB and phosphorylated Bcl-2 Associated death Protein (pBAD) levels, and cell death in SY5Y cells and in rat brain slices, and determined the role of CaN on CREB phosphorylation in the CNS of Tg2576 mice. Our results show that oligomeric Abeta specifically induces CaN activity and promotes CaN-dependent CREB and Bcl-2 Asociated death Protein (BAD) dephosphorylation and cell death. Furthermore, Tg2576 mice display Abeta oligomers and reduced pCREB in the CNS, which is normalized by CaN inhibition. These findings suggest a role for CaN in mediating effects of oligomeric Abeta on neural cells. Because elevated CaN levels have been reported in the CNS of cognitively impaired aged rodents, our results further suggest that abnormal CaN hyperactivity may be a common event exacerbating the cognitive and neurodegenerative impact of oligomeric Abeta in the aging CNS.
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PMID:Selective induction of calcineurin activity and signaling by oligomeric amyloid beta. 1878 50

Glioblastoma is the most malignant brain tumor in humans and an average survival of glioblastoma patients hardly exceeds 12 months. Taxol is a plant-derived anti-cancer agent, which has been used in the treatments of many solid tumors. Deletion or mutation of phosphatase and tension homolog located on chromosome ten (PTEN) occurs in more than 80% of glioblastomas. We examined the sensitivity of human glioblastoma LN18 (PTEN-positive) and A172 (PTEN-negative) cells to Taxol for induction of apoptosis. Wright staining showed morphological features of apoptosis after treatment with different doses of Taxol for 24 h. Significant amount of apoptosis occurred in LN18 cells after treatment with 25 nM Taxol, while in A172 cells only after treatment with 50 nM Taxol. Western blotting with an antibody that could specifically detect activation or phosphorylation of Akt (p-Akt) did not show any p-Akt in LN18 cells but an increase in p-Akt in A172 cells. Activation of Akt in A172 cells could be reversed by pre-treatment of the cells with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002, indicating involvement of PI3K activity in this process. Apoptosis occurred with an increase in Bax:Bcl-2 and mitochondrial release of cytochrome c into the cytosol leading to activation of mitochondria-dependent caspase cascade. Taxol did not cause upregulation of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, in LN18 cells but substantial upregulation of VEGF in A172 cells. After treatment with Taxol, increases in p-Akt and VEGF could maintain survival and angiogenesis, respectively, in PTEN-negative glioblastoma. As a single chemotherapy, Taxol might be more efficacious in PTEN-positive glioblastoma than in PTEN-negative glioblastoma. Thus, our study showed differential sensitivity of PTEN-positive and PTEN-negative glioblastoma cells to Taxol.
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PMID:Differential sensitivity of human glioblastoma LN18 (PTEN-positive) and A172 (PTEN-negative) cells to Taxol for apoptosis. 1880 99

Multiple oncogenes (in particular phosphatidylinositol 3-kinase, PI3K; activated Akt1; antiapoptotic proteins from the Bcl-2 family) inhibit autophagy. Similarly, several tumor suppressor proteins (such as BH3-only proteins; death-associated protein kinase-1, DAPK1; the phosphatase that antagonizes PI3K, PTEN; tuberous sclerosic complex 1 and 2, TSC1 and TSC2; as well as LKB1/STK11) induce autophagy, meaning that their loss reduces autophagy. Beclin-1, which is required for autophagy induction acts as a haploinsufficient tumor suppressor protein, and other essential autophagy mediators (such as Atg4c, UVRAG and Bif-1) are bona fide oncosuppressors. One of the central tumor suppressor proteins, p53 exerts an ambiguous function in the regulation of autophagy. Within the nucleus, p53 can act as an autophagy-inducing transcription factor. Within the cytoplasm, p53 exerts a tonic autophagy-inhibitory function, and its degradation is actually required for the induction of autophagy. The role of autophagy in oncogenesis and anticancer therapy is contradictory. Chronic suppression of autophagy may stimulate oncogenesis. However, once a tumor is formed, autophagy inhibition may be a therapeutic goal for radiosensitization and chemosensitization. Altogether, the current state-of-the art suggests a complex relationship between cancer and deregulated autophagy that must be disentangled by further in-depth investigation.
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PMID:Control of autophagy by oncogenes and tumor suppressor genes. 1880 60

Bcl-2 is an anti-apoptotic protein that is frequently overexpressed in cancer cells but its role in carcinogenesis is not clear. We are interested in how Bcl-2 expression affects non-cancerous breast cells and its role in the cell cycle. We prepared an MCF10A breast epithelial cell line that stably overexpressed Bcl-2. We analyzed the cells by flow cytometry after synchronization, and used cDNA microarrays with quantitative reverse-transcription PCR (qRT-PCR) to determine differences in gene expression. The microarray data was subjected to two pathway analysis tools, parametric analysis of gene set enrichment (PAGE) and ingenuity pathway analysis (IPA), and western analysis was carried out to determine the correlation between mRNA and protein levels. The MCF10A/Bcl-2 cells exhibited a slow-growth phenotype compared to control MCF10A/Neo cells that we attributed to a slowing of the G(1)-S cell cycle transition. A total of 363 genes were differentially expressed by at least two-fold, 307 upregulated and 56 downregulated. PAGE identified 22 significantly changed gene sets. The highest ranked network of genes identified by IPA contained 24 genes. Genes that were chosen for further analysis were confirmed by qRT-PCR, however, the western analysis did not always confirm differential expression of the proteins. Downregulation of the phosphatase CDC25A could solely be responsible for the slow growth phenotype in MCF10A/Bcl-2 cells. Increased levels of GTPase Cdc42 could be adding to this effect. PAGE and IPA are valuable tools for microarray analysis, but protein expression results do not always follow mRNA expression results.
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PMID:Microarray and pathway analysis reveals decreased CDC25A and increased CDC42 associated with slow growth of BCL2 overexpressing immortalized breast cell line. 1883 68

Atrogin-1/MAFbx is a major atrophy-related E3 ubiquitin ligase that is expressed specifically in striated muscle. Although the contribution of atrogin-1 to cardiac and muscle hypertrophy/atrophy has been examined extensively, it remains unclear whether atrogin-1 plays an essential role in the simulated ischemia/reperfusion-induced apoptosis of primary cardiomyocytes. Here we showed that atrogin-1 markedly enhanced ischemia/reperfusion-induced apoptosis in cardiomyocytes via activation of JNK signaling. Overexpression of atrogin-1 increased phosphorylation of JNK and c-Jun and decreased phosphorylation of Foxo3a. In addition, atrogin-1 decreased Bcl-2, increased Bax, and enhanced the activation of caspases. Furthermore, JNK inhibitor SP600125 markedly blocked the effect of atrogin-1 on cell apoptosis and the expression of apoptotic-related proteins and caspases. Importantly, atrogin-1 induced sustained activation of JNK through a mechanism that involved degradation of MAPK phosphatase-1 (MKP-1) protein. Atrogin-1 interacted with and triggered MKP-1 for ubiquitin-mediated degradation. In contrast, proteasome inhibitors markedly blocked the degradation of MKP-1. Taken together, these results demonstrate that atrogin-1 promotes degradation of MKP-1 through the ubiquitin-proteasome pathway, thereby leading to persistent activation of JNK signaling and further cardiomyocyte apoptosis following ischemia/reperfusion injury.
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PMID:Atrogin-1/MAFbx enhances simulated ischemia/reperfusion-induced apoptosis in cardiomyocytes through degradation of MAPK phosphatase-1 and sustained JNK activation. 1911 50

Activation of signal transducers and activators of transcription-3 (STAT-3) has been linked with survival, proliferation, chemoresistance, and angiogenesis of tumor cells, including human multiple myeloma (MM). Thus, agents that can suppress STAT3 activation have potential as cancer therapeutics. In our search for such agents, we identified acetyl-11-keto-beta-boswellic acid (AKBA), originally isolated from Boswellia serrata. Our results show that AKBA inhibited constitutive STAT3 activation in human MM cells. AKBA suppressed IL-6-induced STAT3 activation, and the inhibition was reversible. The phosphorylation of both Jak 2 and Src, constituents of the STAT3 pathway, was inhibited by AKBA. Interestingly, treatment of cells with pervanadate suppressed the effect of AKBA to inhibit the phosphorylation of STAT3, thus suggesting the involvement of a protein tyrosine phosphatase. We found that AKBA induced Src homology region 2 domain-containing phosphatase 1 (SHP-1), which may account for its role in dephosphorylation of STAT3. Moreover, deletion of the SHP-1 gene by small interfering RNA abolished the ability of AKBA to inhibit STAT3 activation. The inhibition of STAT3 activation by AKBA led to the suppression of gene products involved in proliferation (cyclin D1), survival (Bcl-2, Bcl-xL, and Mcl-1), and angiogenesis (VEGF). This effect correlated with the inhibition of proliferation and apoptosis in MM cells. Consistent with these results, overexpression of constitutive active STAT3 significantly reduced the AKBA-induced apoptosis. Overall, our results suggest that AKBA is a novel inhibitor of STAT3 activation and has potential in the treatment of cancer.
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PMID:Boswellic acid blocks signal transducers and activators of transcription 3 signaling, proliferation, and survival of multiple myeloma via the protein tyrosine phosphatase SHP-1. 3018 Dec 8

The protein kinase Akt plays an important role in cell proliferation and survival in many cancers, including prostate cancer. Due to its kinase activity, it serves as a molecular conduit for inhibiting apoptosis and promoting angiogenesis in most cell types. In most of the prostate tumors, Akt signaling is constitutively activated due to the deletion or mutation of the tumor suppressor PTEN, which negatively regulates phosphatidylinositol 3-kinase through lipid phosphatase activity. Recently, we identified a natural compound, psoralidin, which inhibits Akt phosphorylation, and its consequent activation in androgen-independent prostate cancer (AIPC) cells. Furthermore, ectopic expression of Akt renders AIPC cells resistant to chemotherapy; however, psoralidin overcomes Akt-mediated resistance and induces apoptosis in AIPC cells. While dissecting the molecular events, both upstream and downstream of Akt, we found that psoralidin inhibits phosphatidylinositol 3-kinase activation and transcriptionally represses the activation of nuclear factor-kappaB and its target genes (Bcl-2, Survivin, and Bcl-xL, etc.), which results in the inhibition of cell viability and induction of apoptosis in PC-3 and DU-145 cells. Interestingly, psoralidin selectively targets cancer cells without causing any toxicity to normal prostate epithelial cells. In vivo xenograft assays substantiate these in vitro findings and show that psoralidin inhibits prostate tumor growth in nude mice. Our findings are of therapeutic significance in the management of prostate cancer patients with advanced or metastatic disease, as they provide new directions for the development of a phytochemical-based platform for prevention and treatment strategies for AIPC.
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PMID:Psoralidin, an herbal molecule, inhibits phosphatidylinositol 3-kinase-mediated Akt signaling in androgen-independent prostate cancer cells. 2202 47

Although cisplatin is a very effective anticancer agent against several types of cancer including ovarian cancer, the mechanisms of acquired resistance are not fully understood. By chronically exposing cisplatin to ovarian cancer cell lines, we established two cisplatin-resistant cell lines OV433 and TOV112D. Our results indicate that the mechanisms underlying their cisplatin resistance are distinct. In OV433 cells, cisplatin resistance is associated with increased expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1). By knocking down MKP-1 expression by siRNA or inhibiting MKP-1 expression by its pharmacological inhibitor triptolide, cisplatin-resistant OV433 cells became cisplatin-sensitive and subsequently increased cisplatin-induced apoptosis. In TOV112D cells, on the other hand, acquired cisplatin resistance is associated with increased levels of Bcl-2 protein. By inhibiting the activity of Bcl-2 protein with its pharmacological inhibitor gossypol or knocking down Bcl-2 expression by siRNA, cisplatin-resistant TOV112D cells became cisplatin-sensitive and subsequently increased cisplatin-induced apoptosis. Therefore, our data suggest that the mechanisms of acquired cisplatin resistance vary among ovarian cancer cells, which involve upregulation of molecules associated with the cell survival pathways.
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PMID:Involvement of MKP-1 and Bcl-2 in acquired cisplatin resistance in ovarian cancer cells. 1985 82


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