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1.
QJM ; 113(9): 643-650, 2020 Sep 01.
Article in English | MEDLINE | ID: mdl-32186731

ABSTRACT

OBJECTIVE: Air pollution had been reported to be associated with the reproductive health of women. However, the association of particulate matter (PM) and acid gases air pollution with premenstrual syndrome (PMS) warrants investigation. This study investigated the effects of air pollution on PMS risk. POPULATION: We combined data from the Taiwan Air Quality-Monitoring Database and the Longitudinal Health Insurance Database. In total, an observational cohort of 85 078 Taiwanese women not diagnosed as having PMS. METHODS: Air pollutant concentrations were grouped into four levels based on the concentration quartiles of several types of air pollutants. MAIN OUTCOME MEASURES: We then applied univariable and multivariable Cox proportional hazard regression models to assess PMS risk in association with each pollutant type. RESULTS: Women exposed to Q4-level SO2 exhibited a 7.77 times higher PMS risk compared with those to Q1-level SO2 (95% confidence interval [CI] = 6.22-9.71). Women exposed to Q4-level NOx exhibited a 2.86 times higher PMS risk compared with those exposed to Q1-level NOx (95% CI = 2.39-3.43). Women exposed to Q4-level NO exhibited a 3.17 times higher PMS risk compared with women exposed to Q1-level NO (95% CI = 2.68-3.75). Finally, women exposed to Q4-level PM with a ≤2.5-µm diameter (PM2.5) exhibited a 3.41 times higher PMS risk compared with those exposed to Q1-level PM2.5 (95% CI = 2.88-4.04). CONCLUSIONS: High incidences of PMS were noted in women who lived in areas with higher concentrations of SO2, NOx, NO, NO2 and PM2.5.


Subject(s)
Air Pollutants/analysis , Air Pollution/adverse effects , Particulate Matter/analysis , Premenstrual Syndrome/epidemiology , Adolescent , Adult , Air Pollution/statistics & numerical data , Atmosphere/chemistry , Cohort Studies , Female , Humans , Hydrogen-Ion Concentration , Middle Aged , Multivariate Analysis , Nitrates/analysis , Ozone/analysis , Proportional Hazards Models , Sulfates/analysis , Taiwan/epidemiology , Young Adult
2.
Oncogenesis ; 6(5): e335, 2017 May 15.
Article in English | MEDLINE | ID: mdl-28504690

ABSTRACT

Despite advances in early diagnosis and the development of molecularly targeted therapy, curative treatment of colon cancer once it has metastasized is yet to be accomplished. This is closely associated with deregulated CRC cell proliferation and resistance to apoptosis. Here we reveal that upregulation of microRNA-645 (miR-645) through DNA copy number gain is responsible for enhanced proliferation and resistance to apoptosis in colon cancer. MiR-645 was upregulated in most colon cancer tissues related to adjacent normal mucosa. This appeared to be associated with amplification of a section of chromosome 20q13.13, where miR-645 is located. Inhibition of miR-645 reduced proliferation and enhanced sensitivity to apoptosis triggered by the chemotherapeutic drugs 5-fluorouracil and cisplatin in CRC cells, and retarded colon cancer xenograft growth. Conversely, overexpression of miR-645 in normal colon epithelial cells enhanced proliferation and triggered anchorage-independent cell growth. Although SRY-related HMG-box 30 (SOX30) was identified as a miR-645 target, its expression was only partially affected by miR-645, suggesting that miR-645 is a fine-tuning mechanism of SOX30 expression. Moreover, overexpression of SOX30 only moderately inhibited promotion of CRC cell proliferation by miR-645, indicating that miR-645 may have more targets that contribute to its pro-proliferation effect in colon cancer. Together, this study reveals that miR-645 can regulate oncogenesis in colon cancer with SOX30 being one of its targets.

4.
Oncogene ; 35(23): 3049-61, 2016 06 09.
Article in English | MEDLINE | ID: mdl-26411369

ABSTRACT

Inositol polyphosphate 4-phosphatase type II (INPP4B) negatively regulates phosphatidylinositol 3-kinase signaling and is a tumor suppressor in some types of cancers. However, we have found that it is frequently upregulated in human colon cancer cells. Here we show that silencing of INPP4B blocks activation of Akt and serum- and glucocorticoid-regulated kinase 3 (SGK3), inhibits colon cancer cell proliferation and retards colon cancer xenograft growth. Conversely, overexpression of INPP4B increases proliferation and triggers anchorage-independent growth of normal colon epithelial cells. Moreover, we demonstrate that the effect of INPP4B on Akt and SGK3 is associated with inactivation of phosphate and tensin homolog through its protein phosphatase activity and that the increase in INPP4B is due to Ets-1-mediated transcriptional upregulation in colon cancer cells. Collectively, these results suggest that INPP4B may function as an oncogenic driver in colon cancer, with potential implications for targeting INPP4B as a novel approach to treat this disease.


Subject(s)
Colonic Neoplasms/genetics , Phosphoric Monoester Hydrolases/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Humans , Immunohistochemistry , Phosphoric Monoester Hydrolases/metabolism
5.
Ann Oncol ; 27(3): 409-16, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26681673

ABSTRACT

Evasion of immune system is a hallmark of cancer, which enables cancer cells to escape the attack from immune cells. Cancer cells can express many immune inhibitory signalling proteins to cause immune cell dysfunction and apoptosis. One of these inhibitory molecules is programmed death-ligand-1 (PD-L1), which binds to programmed death-1 (PD-1) expressed on T-cells, B-cells, dendritic cells and natural killer T-cells to suppress anti-cancer immunity. Therefore, anti-PD-L1 and anti-PD-1 antibodies have been used for the treatment of cancer, showing promising outcomes. However, only a proportion of patients respond to the treatments. Further understanding of the regulation of PD-L1 expression could be helpful for the improvement of anti-PD-L1 and anti-PD-1 treatments. Studies have shown that PD-L1 expression is regulated by signalling pathways, transcriptional factors and epigenetic factors. In this review, we summarise the recent progress of the regulation of PD-L1 expression in cancer cells and propose a regulatory model for unified explanation. Both PI3K and MAPK pathways are involved in PD-L1 regulation but the downstream molecules that control PD-L1 and cell proliferation may differ. Transcriptional factors hypoxia-inducible factor-1α and signal transducer and activation of transcription-3 act on the promoter of PD-L1 to regulate its expression. In addition, microRNAs including miR-570, miR-513, miR-197, miR-34a and miR-200 negatively regulate PD-L1. Clinically, it could increase treatment efficacy of targeted therapy by choosing those molecules that control both PD-L1 expression and cell proliferation.


Subject(s)
B7-H1 Antigen/metabolism , Mitogen-Activated Protein Kinases/metabolism , Neoplasms/immunology , Phosphatidylinositol 3-Kinases/metabolism , Programmed Cell Death 1 Receptor/metabolism , Signal Transduction/immunology , Tumor Escape/immunology , B-Lymphocytes/immunology , B7-H1 Antigen/genetics , B7-H1 Antigen/immunology , Biomarkers, Tumor , Cell Proliferation , Dendritic Cells/immunology , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , MicroRNAs/genetics , NF-kappa B/metabolism , Natural Killer T-Cells/immunology , Neoplasms/metabolism , Programmed Cell Death 1 Receptor/immunology , Promoter Regions, Genetic/genetics , Protein Binding/immunology , STAT3 Transcription Factor/metabolism , T-Lymphocytes/immunology
6.
Rev Sci Instrum ; 86(5): 056110, 2015 May.
Article in English | MEDLINE | ID: mdl-26026571

ABSTRACT

The hot cathode ion source will tend to be unstable when operated with high power and long pulse. In order to achieve stable operation, a new regulation method based on the arc power (discharge power) feedback control was designed and tested on the hot cathode ion source test bed with arc discharge and beam extraction. The results show that the new regulation method can achieve stable arc discharge and beam extraction. It verifies the success of feedback control of arc source with arc power.

7.
Oncogene ; 33(39): 4756-66, 2014 Sep 25.
Article in English | MEDLINE | ID: mdl-24121273

ABSTRACT

Akt is constitutively activated in up to 70% of human melanomas and has an important role in the pathogenesis of the disease. However, little is known about protein phosphatases that dephosphorylate and thereby inactivate it in melanoma cells. Here we report that suppression of pleckstrin homology domain and leucine-rich repeat Ser/Thr protein phosphatase 1 (PHLPP1) by DNA methylation promotes Akt activation and has an oncogenic role in melanoma. While it is commonly downregulated, overexpression of PHLPP1 reduces Akt activation and inhibits melanoma cell proliferation in vitro, and retards melanoma growth in a xenograft model. In contrast, knockdown of PHLPP1 increases Akt activation, enhances melanoma cell and melanocyte proliferation, and results in anchorage-independent growth of melanocytes. Suppression of PHLPP1 involves blockade of binding of the transcription factor Sp1 to the PHLPP1 promoter. Collectively, these results suggest that suppression of PHLPP1 by DNA methylation contributes to melanoma development and progression.


Subject(s)
Gene Expression Regulation, Neoplastic , Gene Silencing , Melanoma/genetics , Nuclear Proteins/genetics , Phosphoprotein Phosphatases/genetics , Animals , Cell Line, Tumor , Cell Proliferation , Cell Survival , DNA Methylation , Down-Regulation , Enzyme Activation , Humans , Male , Melanoma/metabolism , Melanoma/pathology , Mice , Mice, Nude , Nuclear Proteins/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoprotein Phosphatases/metabolism , Promoter Regions, Genetic , Proto-Oncogene Proteins c-akt/metabolism , Sp1 Transcription Factor/metabolism , Tumor Burden
8.
Oncogene ; 33(20): 2577-88, 2014 May 15.
Article in English | MEDLINE | ID: mdl-23770856

ABSTRACT

Increased global protein synthesis and selective translation of mRNAs encoding proteins contributing to malignancy is common in cancer cells. This is often associated with elevated expression of eukaryotic translation initiation factor 4 (eIF4E), the rate-limiting factor of cap-dependent translation initiation. We report here that in human melanoma downregulation of miR-768-3p as a result of activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway has an important role in the upregulation of eIF4E and enhancement in protein synthesis. Melanoma cells displayed increased nascent protein production and elevated eIF4E expression, which was associated with the downregulation of miR-768-3p that was predicted to target the 3'-untranslated region of the eIF4E mRNA. Overexpression of miR-768-3p led to the downregulation of the endogenous eIF4E protein, reduction in nascent protein synthesis and inhibition of cell survival and proliferation. These effects were efficiently reversed when eIF4E was co-overexpressed in melanoma cells. On the other hand, introduction of anti-miR-768-3p into melanocytes upregulated endogenous eIF4E protein expression and increased global protein synthesis. Downregulation of miR-768-3p appeared to be mediated by activation of the MEK/ERK pathway, in that treatment of BRAF(V600E) melanoma cells with the mutant BRAF inhibitor PLX4720 or exposure of either BRAF(V600E) or wild-type BRAF melanoma cells to the MEK inhibitor U0126 resulted in the upregulation of miR-768-3p and inhibition of nascent protein synthesis. This inhibition was partially blocked in cells cointroduced with anti-miR-768-3p. Significantly, miR-768-3p was similarly downregulated, which was inversely associated with the expression levels of eIF4E in fresh melanoma isolates. Taken together, these results identify downregulation of miR-768-3p and subsequent upregulation of eIF4E as an important mechanism in addition to phosphorylation of eIF4E responsible for MEK/ERK-mediated enhancement of protein synthesis in melanoma.


Subject(s)
MAP Kinase Signaling System , Melanoma/genetics , MicroRNAs/genetics , Protein Biosynthesis , RNA, Messenger/genetics , Signal Transduction , Cell Line, Tumor , Down-Regulation , Eukaryotic Initiation Factor-4E/metabolism , Humans , Melanoma/metabolism , Melanoma/pathology , Up-Regulation
9.
Curr Med Chem ; 21(10): 1255-67, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24304284

ABSTRACT

Epidemiological evidence has linked the development and progression of several cancers including melanoma with obesity. However, whether obesity impinges on responses of cancer cells to treatment remains less understood. Here we report that human adipocytes contribute to resistance of melanoma cells to various therapeutic agents. Exposure to media from adipocyte cultures (adipocyte media) increased cell proliferation and reduced sensitivity of melanoma cells to apoptosis induced by diverse chemotherapeutic drugs, including the DNA-damaging drug cisplatin, the microtubuletargeting agent docetaxel, and the histone deacetylase inhibitor SAHA. This was associated with increased activation of PI3K/Akt and MEK/ERK signaling, and was attenuated by a PI3K or MEK inhibitor. The effect of adipocyte media on melanoma cells was, at least in part, due to the interaction between the adipokine leptin and its long form receptor OB-Rb, in that immunodepletion of leptin in adipocyte media or siRNA knockdown of OB-Rb in melanoma cells reversed the increase in Akt and ERK activation, enhancement in cell proliferation, and importantly, protection of melanoma cells against the drugs. In support, recombinant leptin partially recapitulated the effect of adipocyte media on melanoma cells. Of note, OB-Rb was increased on the surface of melanoma cells compared to melanocytes, whereas leptin short form receptors appeared to be suppressed post-transcriptionally, suggesting that OB-Rb was selectively upregulated in melanoma cells. Collectively, these results indicate that adipocytes contribute to the resistance of melanoma cells to chemotherapeutic drugs and agents targeting the PI3K/Akt and MEK/ERK pathways, and suggest that inhibition of the leptin/ OB-Rb system may be useful to improve the efficacy of multiple therapeutic approaches in the treatment of melanoma.


Subject(s)
Adipocytes/metabolism , Antineoplastic Agents/pharmacology , Drug Resistance, Neoplasm/genetics , Gene Expression Regulation, Neoplastic , Keratinocytes/drug effects , Adipocytes/cytology , Cell Line, Tumor , Cell Proliferation/drug effects , Cisplatin/pharmacology , Culture Media, Conditioned/pharmacology , Docetaxel , Histone Deacetylase Inhibitors/pharmacology , Humans , Keratinocytes/metabolism , Keratinocytes/pathology , Leptin/deficiency , Leptin/genetics , MAP Kinase Kinase Kinases/antagonists & inhibitors , MAP Kinase Kinase Kinases/genetics , MAP Kinase Kinase Kinases/metabolism , Molecular Targeted Therapy , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Receptors, Leptin/antagonists & inhibitors , Receptors, Leptin/genetics , Receptors, Leptin/metabolism , Signal Transduction , Taxoids/pharmacology
10.
Cell Death Dis ; 4: e914, 2013 Nov 07.
Article in English | MEDLINE | ID: mdl-24201813

ABSTRACT

An activating BRAF (V600E) kinase mutation occurs in approximately half of melanomas. Recent clinical studies have demonstrated that vemurafenib (PLX4032) and dabrafenib, potent and selective inhibitors of mutant v-raf murine sarcoma viral oncogene homolog B1 (BRAF), exhibit remarkable activities in patients with V600 BRAF mutant melanomas. However, acquired drug resistance invariably develops after the initial treatment. Identification of acquired resistance mechanisms may inform the development of new therapies that elicit long-term responses of melanomas to BRAF inhibitors. Here we report that increased expression of AEBP1 (adipocyte enhancer-binding protein 1) confers acquired resistance to BRAF inhibition in melanoma. AEBP1 is shown to be highly upregulated in PLX4032-resistant melanoma cells because of the hyperactivation of the PI3K/Akt-cAMP response element-binding protein (CREB) signaling pathway. This upregulates AEBP1 expression and thus leads to the activation of NF-κB via accelerating IκBa degradation. In addition, inhibition of the PI3K/Akt-CREB-AEBP1-NF-κB pathway greatly reverses the PLX4032-resistant phenotype of melanoma cells. Furthermore, increased expression of AEBP1 is validated in post-treatment tumors in patients with acquired resistance to BRAF inhibitor. Therefore, these results reveal a novel PI3K/Akt-CREB-AEBP1-NF-κB pathway whose activation contributes to acquired resistance to BRAF inhibition, and suggest that this pathway, particularly AEBP1, may represent a novel therapeutic target for treating BRAF inhibitor-resistant melanoma.


Subject(s)
Carboxypeptidases/metabolism , Melanoma/metabolism , Proto-Oncogene Proteins B-raf/metabolism , Repressor Proteins/metabolism , Animals , CREB-Binding Protein/genetics , CREB-Binding Protein/metabolism , Carboxypeptidases/genetics , Cell Line, Tumor , Chromatin Immunoprecipitation , Drug Resistance, Neoplasm/genetics , Humans , In Vitro Techniques , Indoles/pharmacology , Lentivirus/genetics , Melanoma/drug therapy , Melanoma/genetics , Mice , Mice, Nude , NF-kappa B/metabolism , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , RNA, Small Interfering/genetics , Repressor Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Signal Transduction/genetics , Sulfonamides/pharmacology , Vemurafenib
11.
Cell Death Dis ; 4: e655, 2013 Jun 06.
Article in English | MEDLINE | ID: mdl-23744355

ABSTRACT

Past studies have shown that histone deacetylase (HDAC) and mutant BRAF (v-Raf murine sarcoma viral oncogene homolog B1) inhibitors synergistically kill melanoma cells with activating mutations in BRAF. However, the mechanism(s) involved remains less understood. Here, we report that combinations of HDAC and BRAF inhibitors kill BRAF(V600E) melanoma cells by induction of necrosis. Cotreatment with the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) or panobinostat (LBH589) and the BRAF inhibitor PLX4720 activated the caspase cascade, but caspases appeared dispensable for killing, in that inhibition of caspases did not invariably block induction of cell death. The majority of dying cells acquired propidium iodide positivity instantly when they became positive for Annexin V, suggesting induction of necrosis. This was supported by caspase-independent release of high-mobility group protein B1, and further consolidated by rupture of the plasma membrane and loss of nuclear and cytoplasmic contents, as manifested by transmission electron microscopic analysis. Of note, neither the necrosis inhibitor necrostatin-1 nor the small interference RNA (siRNA) knockdown of receptor-interacting protein kinase 3 (RIPK3) inhibited cell death, suggesting that RIPK1 and RIPK3 do not contribute to induction of necrosis by combinations of HDAC and BRAF inhibitors in BRAF(V600E) melanoma cells. Significantly, SAHA and the clinically available BRAF inhibitor vemurafenib cooperatively inhibited BRAF(V600E) melanoma xenograft growth in a mouse model even when caspase-3 was inhibited. Taken together, these results indicate that cotreatment with HDAC and BRAF inhibitors can bypass canonical cell death pathways to kill melanoma cells, which may be of therapeutic advantage in the treatment of melanoma.


Subject(s)
Antineoplastic Agents/pharmacology , Histone Deacetylase Inhibitors/pharmacology , Melanoma/drug therapy , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Animals , Cell Line, Tumor , Cell Survival/drug effects , Drug Synergism , Gene Knockdown Techniques , Humans , Hydroxamic Acids/pharmacology , Indoles/pharmacology , Male , Mice , Mice, Nude , Mutation, Missense , Necrosis , Panobinostat , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins B-raf/metabolism , RNA, Small Interfering/genetics , Receptor-Interacting Protein Serine-Threonine Kinases/genetics , Sulfonamides/pharmacology , Vemurafenib , Vorinostat , Xenograft Model Antitumor Assays
12.
Osteoarthritis Cartilage ; 21(4): 589-98, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23333470

ABSTRACT

OBJECTIVE: Matrix-associated autologous chondrocyte implantation has been used to treat cartilage defects. We developed a biphasic cylindrical osteochondral composite construct for such use, and conducted this study to determine its feasibility for treating osteochondral lesions in human knees. METHOD: Ten patients with symptomatic osteochondral lesions at femoral condyles were treated by replacing pathological tissue with the construct of dl-poly-lactide-co-glycolide, whose lower body was impregnated with ß-tricalcium phosphate and served as osseous phase. The construct had a chamber to load double-minced autologous cartilage, serving as source of chondrocytes. Osteochondral lesion was drill-fashioned a pit of identical dimension as the construct. Chondrocyte-laden construct was press-fit to fill the pit. Postoperative outcome was evaluated using Knee Injury and Osteoarthritis Outcome Score (KOOS) scale up to 24 months. Magnetic resonance image was taken, and sample tissue was collected with second-look arthroscopic needle biopsy at 12 months. Outcome parameters were primarily safety of surgery, and secondarily postoperative change in KOOS and regeneration of hyaline cartilage and cancellous bone. RESULTS: No patient experienced serious adverse events. Postoperative mean KOOS in "symptoms" subscale had not changed significantly from pre-operation until 24 months; whereas those in the other four subscales were significantly higher than pre-operation at 12 and 24 months. Second-look arthroscopy showed completely filled grafted sites, with regenerate cartilaginous surfaces flushed with surrounding native joint surface. Microscopically, regenerated cartilage appeared hyaline. CONCLUSION: This novel construct for chondrocyte implantation is safe for surgical application in knee. It repairs osteochondral lesions of femoral condyles by successful regeneration of hyaline cartilage.


Subject(s)
Chondrocytes/transplantation , Knee Injuries/surgery , Knee Joint/surgery , Tissue Scaffolds , Adult , Arthroscopy , Bone Regeneration/physiology , Cartilage, Articular/injuries , Cartilage, Articular/pathology , Cartilage, Articular/physiology , Feasibility Studies , Female , Humans , Knee Joint/pathology , Knee Joint/physiology , Lactic Acid , Magnetic Resonance Imaging , Male , Middle Aged , Osteochondritis Dissecans/surgery , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer , Postoperative Complications , Regeneration , Severity of Illness Index , Tissue Engineering/methods , Treatment Outcome , Young Adult
13.
Oncogene ; 32(15): 1910-20, 2013 Apr 11.
Article in English | MEDLINE | ID: mdl-22710713

ABSTRACT

Past studies have shown that amplified insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1-R) signalling has an important role in colorectal cancer (CRC) development, progression and resistance to treatment. In this report, we demonstrate that downregulation of microRNA-497 (miR-497) as a result of DNA copy number reduction is involved in upregulation of IGF1-R in CRC cells. MiR-497 and miR-195 of the miR-15/16/195/424/497 family that share the same 3' untranslated region (3'UTR) binding seed sequence and are predicted to target IGF1-R were concurrently downregulated in the majority of CRC tissues relative to paired adjacent normal mucosa. However, only overexpression of miR-497 led to suppression of the IGF1-R 3'UTR activity and downregulation of the endogenous IGF1-R protein in CRC cells. This was associated with inhibition of cell survival, proliferation and invasion, and increased sensitivity to apoptosis induced by various stimuli including the chemotherapeutic drugs cisplatin and 5-fluorouracil, and the death ligand tumour necrosis factor-related apoptosis-inducing ligand. The biological effect of miR-497 on CRC cells was largely mediated by inhibition of phosphatidylinositol 3-kinase/Akt signalling, as overexpression of an active form of Akt reversed its impact on cell survival and proliferation, recapitulating the effect of overexpression of IGF1-R. Downregulation of miR-497 and miR-195 appeared to associate with copy number loss of a segment of chromosome 17p13.1, where these miRs are located at proximity. Similarly to miR-195, the members of the same miR family, miR-424 that was upregulated, and miR-15a, miR-15b and miR-16 that were unaltered in expression in CRC tissues compared with paired adjacent normal mucosa, did not appear to have a role in regulating the expression of IGF1-R. Taken together, these results identify downregulation of miR-497 as an important mechanism of upregulation of IGF1-R in CRC cells that contributes to malignancy of CRC.


Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , DNA Copy Number Variations , MicroRNAs/metabolism , Receptor, IGF Type 1/metabolism , 3' Untranslated Regions , Apoptosis/genetics , Cell Line, Tumor , Cell Proliferation , Cell Survival/genetics , Cisplatin/pharmacology , Disease Progression , Down-Regulation , Drug Resistance, Neoplasm/genetics , Fluorouracil/pharmacology , Gene Expression Regulation, Neoplastic , Humans , Insulin-Like Growth Factor I/metabolism , MicroRNAs/genetics , Neoplasm Invasiveness/genetics , Phosphatidylinositol 3-Kinase/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/genetics
14.
Cell Death Dis ; 3: e337, 2012 Jun 28.
Article in English | MEDLINE | ID: mdl-22739989

ABSTRACT

Endoplasmic reticulum (ER) stress triggers apoptosis by activating Bim in diverse types of cells, which involves dephosphorylation of Bim(EL) by protein phosphatase 2A (PP2A). However, melanoma cells are largely resistant to ER stress-induced apoptosis, suggesting that Bim activation is suppressed in melanoma cells undergoing ER stress. We show here that ER stress reduces PP2A activity leading to increased ERK activation and subsequent phosphorylation and proteasomal degradation of Bim(EL). Despite sustained upregulation of Bim at the transcriptional level, the Bim(EL) protein expression was downregulated after an initial increase in melanoma cells subjected to pharmacological ER stress. This was mediated by increased activity of ERK, whereas the phosphatase activity of PP2A was reduced by ER stress in melanoma cells. The increase in ERK activation was, at least in part, due to reduced dephosphorylation by PP2A, which was associated with downregulation of the PP2A catalytic C subunit. Notably, instead of direct dephosphorylation of Bim(EL), PP2A inhibited its phosphorylation indirectly through dephosphorylation of ERK in melanoma cells. Taken together, these results identify downregualtion of PP2A activity as an important protective mechanism of melanoma cells against ER stress-induced apoptosis.


Subject(s)
Endoplasmic Reticulum Stress , Melanoma/metabolism , Protein Phosphatase 2/genetics , Apoptosis , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Bcl-2-Like Protein 11 , Cell Line, Tumor , Down-Regulation , Humans , Melanoma/genetics , Melanoma/pathology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Phosphorylation , Protein Phosphatase 2/metabolism , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Signal Transduction , Transcription, Genetic , Up-Regulation
15.
Oncogene ; 30(34): 3716-26, 2011 Aug 25.
Article in English | MEDLINE | ID: mdl-21423203

ABSTRACT

Past studies have shown that upregulation of the anti-apoptotic Bcl-2 family protein Mcl-1 is a major adaptive mechanism of melanoma cells to endoplasmic reticulum (ER) stress, and has an important role in resistance of the cells to apoptosis. In this study, we show that the increase in transcription of Mcl-1 in melanoma cells triggered by pharmacological ER stress inducers is mediated by the transcription factor Ets-1. By incremental deletion analysis of the Mcl-1 promoter, we identified a DNA fragment containing an Ets-1 binding site that is transcriptionally responsive to ER stress. Mutations in the Ets-1 binding site or knockdown of Ets-1 inhibited the increase in Mcl-1, indicating that Ets-1 has a critical role in transcriptional upregulation of Mcl-1. Similar to Mcl-1, Ets-1 was transcriptionally upregulated by ER stress. This was mediated by the IRE1α/XBP-1 branch of the unfolded protein response, as upregulation of Ets-1 was inhibited in melanoma cell lines deficient in IRE1α or XBP-1 established by short hairpin RNA knockdown. Activation of the PI3k/Akt pathway downstream of XBP-1 was also involved, in that inhibition of the pathway blocked upregulation of Ets-1. Inhibition of Ets-1 enhanced ER stress-induced apoptosis in melanoma cell lines and in fresh melanoma isolates, recapitulating the effect of inhibition of Mcl-1. These results reveal a key mechanism by which Mcl-1 is transcriptionally upregulated in melanoma cells by ER stress, and identify Ets-1 as a potential target for inhibition to sensitize melanoma cells to apoptosis.


Subject(s)
DNA-Binding Proteins/physiology , Endoplasmic Reticulum/metabolism , Melanoma/metabolism , Proto-Oncogene Protein c-ets-1/physiology , Proto-Oncogene Proteins c-bcl-2/physiology , Transcription Factors/physiology , Up-Regulation/physiology , Apoptosis , Base Sequence , Blotting, Western , Cell Line, Tumor , Chromatin Immunoprecipitation , DNA Primers , Electrophoretic Mobility Shift Assay , Humans , Melanoma/pathology , Myeloid Cell Leukemia Sequence 1 Protein , Polymerase Chain Reaction , Promoter Regions, Genetic , Proto-Oncogene Proteins c-bcl-2/genetics , Regulatory Factor X Transcription Factors , Transcription, Genetic , X-Box Binding Protein 1
16.
Cell Death Differ ; 17(8): 1354-67, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20300110

ABSTRACT

Past studies have identified a number of distinct mechanisms that contribute to the resistance of melanoma cells against apoptosis induced by TNF-related apoptosis-inducing ligand (TRAIL). In this report we show that cystatin B is another endogenous inhibitor of TRAIL-induced apoptosis. Cystatin B-deficient melanoma cell lines established by shRNA knockdown displayed increased apoptosis that was associated with enhanced activation of caspase-8 induced by TRAIL. This was not related to the inhibitory effect of cystatin B on the lysosomal cysteine proteases, cathepsin B and L, as they did not have a role in TRAIL-induced apoptosis in most melanoma cell lines even when cystatin B was inhibited. Instead, sensitization of melanoma cells to TRAIL-induced apoptosis by inhibition of cystatin B appeared associated with decreased stability of FLIP(L) as the levels of FLIP(L) were reduced because of shortened half-life time in melanoma cells deficient in cystatin B. In contrast, over-expression of cystatin B increased the levels of FLIP(L), decreased the amount of the E3 ligase Itch associated with FLIP(L), and reduced FLIP(L) ubiquitination. Inhibition of Itch by siRNA restored the levels of FLIP(L) and blocked sensitization to TRAIL-induced apoptosis associated with deficiency in cystatin B. Taken together, these results indicate that cystatin B regulates Itch-mediated degradation of FLIP(L) and thereby TRAIL-induced apoptosis in melanoma cells.


Subject(s)
Apoptosis , CASP8 and FADD-Like Apoptosis Regulating Protein/metabolism , Cystatin B/metabolism , Melanoma/metabolism , Repressor Proteins/metabolism , TNF-Related Apoptosis-Inducing Ligand/pharmacology , Ubiquitin-Protein Ligases/metabolism , Caspase 8/metabolism , Cell Line, Tumor , Cystatin B/genetics , Gene Knockdown Techniques , Humans , Melanoma/enzymology , RNA Interference , RNA, Small Interfering/metabolism
17.
Acta Neurol Scand ; 122(5): 350-9, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20085559

ABSTRACT

OBJECTIVE: The application of biomarkers may potentially improve the efficiency of the diagnosis for Parkinson's disease (PD). However, no reliable biomarker has been identified to date. This study is aimed to identify proteins that might serve as potential biomarkers for PD diagnosis or pathogenesis. MATERIALS AND METHODS: Two-dimensional difference gel electrophoresis (2D DIGE) technique, in combination with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), was used to determine the differentially expressed cerebrospinal fluid (CSF) proteins in PD patients (n = 3) compared with normal controls (n = 3). Selected proteins were further confirmed by Western blotting analysis in the CSF of PD patients (n = 8), Alzheimer's disease (AD) patients (n = 6) and normal control subjects (n = 7). RESULTS: Eight proteins were identified after MS and protein database interrogation. In the CSF of PD patients, the expression levels of one isoform of apolipoprotein A-I (apoA-I), tetranectin, myosin phosphatase target subunit 1 (MYPT1), and two unknown proteins were down-regulated, whereas the expression levels of another apoA-I isoform, proapolipoprotein, and lipoprotein were up-regulated. Western blotting indicates that the expression of tetranectin was reduced in the CSF from PD patients and elevated in AD, while the expression of apoA-I was changed only in the CSF from PD patients. CONCLUSION: Our preliminary results suggest that tetranectin and apoA-I may serve as potential biomarkers for PD, though further validation is needed.


Subject(s)
Apolipoprotein A-I/cerebrospinal fluid , Lectins, C-Type/metabolism , Parkinson Disease/cerebrospinal fluid , Parkinson Disease/diagnosis , Aged , Biomarkers/cerebrospinal fluid , Electrophoresis, Gel, Two-Dimensional/methods , Female , Humans , Male , Mass Spectrometry/methods , Middle Aged , Probability
18.
Opt Express ; 18(26): 27820-6, 2010 Dec 20.
Article in English | MEDLINE | ID: mdl-21197055

ABSTRACT

The modulation function of holographic functional screen (HFS) in the real-time, large-size full-color (RLF), three-dimensional (3D) display system is derived from angular spectrum analysis. The directional laser speckle (DLS) method to realize the HFS is proposed. A HFS by the DLS method was fabricated and used in the experiment. Experimental results show that the HFS is valid in the RLF 3D display, and that the derived modulation function is valuable for the design of the HFS. The research results are important to realize the RLF 3D display system which will find many applications such as holographic video.


Subject(s)
Algorithms , Holography/instrumentation , Holography/methods , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/instrumentation , Imaging, Three-Dimensional/methods , Computer-Aided Design , Equipment Design , Equipment Failure Analysis
19.
Cell Death Dis ; 1: e69, 2010 Sep 02.
Article in English | MEDLINE | ID: mdl-21364673

ABSTRACT

Bim is known to be critical in killing of melanoma cells by inhibition of the RAF/MEK/ERK pathway. However, the potential role of the most potent apoptosis-inducing isoform of Bim, Bim(S), remains largely unappreciated. Here, we show that inhibition of the mutant B-RAF(V600E) triggers preferential splicing to produce Bim(S), which is particularly important in induction of apoptosis in B-RAF(V600E) melanoma cells. Although the specific B-RAF(V600E) inhibitor PLX4720 upregulates all three major isoforms of Bim, Bim(EL), Bim(L), and Bim(S), at the protein and mRNA levels in B-RAF(V600E) melanoma cells, the increase in the ratios of Bim(S) mRNA to Bim(EL) and Bim(L) mRNA indicates that it favours Bim(S) splicing. Consistently, enforced expression of B-RAF(V600E) in wild-type B-RAF melanoma cells and melanocytes inhibits Bim(S) expression. The splicing factor SRp55 appears necessary for the increase in Bim(S) splicing, as SRp55 is upregulated, and its inhibition by small interfering RNA blocks induction of Bim(S) and apoptosis induced by PLX4720. The PLX4720-induced, SRp55-mediated increase in Bim(S) splicing is also mirrored in freshly isolated B-RAF(V600E) melanoma cells. These results identify a key mechanism for induction of apoptosis by PLX4720, and are instructive for sensitizing melanoma cells to B-RAF(V600E) inhibitors.


Subject(s)
Apoptosis Regulatory Proteins/metabolism , Apoptosis , Melanoma/metabolism , Membrane Proteins/metabolism , Proto-Oncogene Proteins B-raf/metabolism , Proto-Oncogene Proteins/metabolism , Amino Acid Substitution , Apoptosis Regulatory Proteins/genetics , Bcl-2-Like Protein 11 , Cell Line, Tumor , Humans , Indoles/pharmacology , Membrane Proteins/genetics , Mutation , Nuclear Proteins/metabolism , Phosphoproteins/metabolism , Protein Isoforms/genetics , Protein Isoforms/metabolism , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/genetics , RNA Interference , RNA Splicing , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism , RNA-Binding Proteins , Serine-Arginine Splicing Factors , Sulfonamides/pharmacology
20.
Opt Lett ; 34(24): 3803-5, 2009 Dec 15.
Article in English | MEDLINE | ID: mdl-20016619

ABSTRACT

A large-size and full-color three-dimensional (3D) display system without the need for special eyeglasses is demonstrated. With a specially fabricated holographic functional screen with a size of 1.8x1.3 m(2), the system including optimally designed camera-projector arrays and a video server can display the fully continuous, natural 3D scene with more than 1 m image depth in real time. We explain the operating principle and present experimental results.

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