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1.
World J Gastrointest Oncol ; 16(6): 2842-2861, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38994129

ABSTRACT

BACKGROUND: Gastrointestinal neoplasm (GN) significantly impact the global cancer burden and mortality, necessitating early detection and treatment. Understanding the evolution and current state of research in this field is vital. AIM: To conducts a comprehensive bibliometric analysis of publications from 1984 to 2022 to elucidate the trends and hotspots in the GN risk assessment research, focusing on key contributors, institutions, and thematic evolution. METHODS: This study conducted a bibliometric analysis of data from the Web of Science Core Collection database using the "bibliometrix" R package, VOSviewer, and CiteSpace. The analysis focused on the distribution of publications, contributions by institutions and countries, and trends in keywords. The methods included data synthesis, network analysis, and visualization of international collaboration networks. RESULTS: This analysis of 1371 articles on GN risk assessment revealed a notable evolution in terms of research focus and collaboration. It highlights the United States' critical role in advancing this field, with significant contributions from institutions such as Brigham and Women's Hospital and the National Cancer Institute. The last five years, substantial advancements have been made, representing nearly 45% of the examined literature. Publication rates have dramatically increased, from 20 articles in 2002 to 112 in 2022, reflecting intensified research efforts. This study underscores a growing trend toward interdisciplinary and international collaboration, with the Journal of Clinical Oncology standing out as a key publication outlet. This shift toward more comprehensive and collaborative research methods marks a significant step in addressing GN risks. CONCLUSION: This study underscores advancements in GN risk assessment through genetic analyses and machine learning and reveals significant geographical disparities in research emphasis. This calls for enhanced global collaboration and integration of artificial intelligence to improve cancer prevention and treatment accuracy, ultimately enhancing worldwide patient care.

2.
J Psychiatr Res ; 145: 111-117, 2021 Nov 25.
Article in English | MEDLINE | ID: mdl-34894520

ABSTRACT

The prevalence of dementia has been widely reported, and its potential risk and protective factors are well-characterized. However, there is a scarcity of related information regarding mild cognitive impairment (MCI). Thus this population-based study aimed to determine the prevalences of MCI and its subtypes, as well as to identify the risk and protective factors for MCI in the Chinese elderly population of Singapore. Results showed that the overall prevalence of MCI was 12.5%, while the gender-adjusted prevalence of MCI was 12.3%. Gender was found to be significantly associated with the subtypes of MCI, with males more likely to have amnestic MCI and females more likely to have non-amnestic MCI. Older age, lower educational levels, lower social activity levels, depression, hypertension, hyperlipidemia, diabetes and stroke were found to be risk factors for MCI in univariate analysis. However, multivariable analysis showed that only hypertension and stroke were the significant risk factors for MCI. Higher educational levels and active social engagements were significant protective factors for MCI in multivariable analysis. Age and depression had boundary significant associations with the prevalence of MCI. After adjusting for gender, the influence of hypertension, stroke, social engagement, age and depression on MCI remained unchanged, except that education became a boundary significant lower risk factor of MCI development. In conclusion, this study presented the prevalence, risk and protective factors for MCI among Singaporean Chinese older adults, which facilitates the screening of vulnerable groups for MCI.

3.
Oncol Lett ; 21(1): 3, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33240409

ABSTRACT

Gastric cancer (GC) is one of the most common malignant tumors with poor prognosis worldwide, mainly due to the lack of suitable modalities for population-based screening and early detection of this disease. Therefore, novel and less invasive tests with improved clinical utility are urgently required. The remarkable advances in genomics and proteomics, along with emerging new technologies for highly sensitive detection of genetic alterations, have shown the potential to map the genomic makeup of a tumor in liquid biopsies, in order to assist with early detection and clinical management. The present review summarize the current status in the identification and development of cell-free DNA (cfDNA)-based biomarkers in GC, and also discusses their potential utility and the technical challenges in developing practical cfDNA-based liquid biopsy for early detection of GC.

4.
Front Oncol ; 10: 1389, 2020.
Article in English | MEDLINE | ID: mdl-32850448

ABSTRACT

The oncogene MDMX, also known as MDM4 is a critical negative regulator of the tumor suppressor p53 and has been implicated in the initiation and progression of human cancers. Increasing evidence indicates that MDMX is often amplified and highly expressed in human cancers, promotes cancer cell growth, and inhibits apoptosis by dampening p53-mediated transcription of its target genes. Inhibiting MDMX-p53 interaction has been found to be effective for restoring the tumor suppressor activity of p53. Therefore, MDMX is becoming one of the most promising molecular targets for developing anticancer therapeutics. In the present review, we mainly focus on the current MDMX-targeting strategies and known MDMX inhibitors, as well as their mechanisms of action and in vitro and in vivo anticancer activities. We also propose other potential targeting strategies for developing more specific and effective MDMX inhibitors for cancer therapy.

5.
Brain Behav ; 9(4): e01251, 2019 04.
Article in English | MEDLINE | ID: mdl-30859753

ABSTRACT

BACKGROUND: Tissue plasminogen activator (t-PA) is an effective therapy for acute ischemic stroke, but some patients still have poor clinical outcome. In this study, we investigated clinical characteristics of stroke patients and determined predictors for poor clinical outcome in response to t-PA treatment. METHODS: Clinical data from 247 patients were retrospectively reviewed. Clinical parameters that were associated with survival of patients were analyzed. Areas under receiver operating characteristic curves (ROC) were used to determine the feasibility of using various combinations of the clinical parameters to predict poor clinical response. The clinical outcome was defined according to the changes in Modified Rankin Scale. RESULTS: Overall, 145 patients had improved/complete recovery, 73 had no change, and 29 had worsening conditions or died during the in-clinic period. A univariate analysis showed that baseline characteristics including age, CRP, blood glucose level, systolic blood pressure, and admission NIHSS were significantly different (p < 0.05) among patients with different clinical outcome. A further multivariate analysis was then performed. Variables associated with poor clinical outcome (worsening/death) (p < 0.1) were included in the logistic regression model. Four parameters were retained in the model: Age, CRP, Blood glucose level, and Systolic blood pressure (ACBS). To allow a convenient usage of the ACBS classifier, the parameters were put into a scoring system, and the score at 7.7 was chosen as a cut-off. The ROC curve of this ACBS classifier has an area under the curve (AUC) of 0.7788, higher than other individual parameters. The ACBS classifier provided enhanced sensitivity of 69.2% and specificity of 74.3%. CONCLUSION: The ACBS classifier provided a satisfactory power in estimating the patients' clinical outcome. After further validating, the classifier may provide important information to clinicians for making clinical decisions.


Subject(s)
Brain Ischemia/drug therapy , Fibrinolytic Agents/therapeutic use , Stroke/drug therapy , Tissue Plasminogen Activator/therapeutic use , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Retrospective Studies , Thrombolytic Therapy , Treatment Outcome
6.
Physiol Behav ; 170: 115-123, 2017 03 01.
Article in English | MEDLINE | ID: mdl-28017679

ABSTRACT

Although Metformin, a first-line antidiabetic drug, can ameliorate ischemia/reperfusion (I/R) induced brain damage, but how metformin benefits injured hippocampus and the mechanisms are still largely unknown. Therefore, the aim of this study was to investigate the neuroprotective mechanisms of metformin against ischemic brain damage induced by cerebral I/R and to explore whether the Akt-mediated down-regulation of the phosphorylation of JNK3 signaling pathway contributed to the protection provided by metformin. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The open field tasks and Morris water maze were used to assess the effect of metformin on anxiety-like behavioral and cognitive impairment after I/R. Cresyl Violet staining was used to examine the survival of hippocampal CA1 pyramidal neurons. Immunoblotting was performed to measure the phosphorylation of Akt1, JNK3, c-Jun and the expression of cleaved caspase-3. Through ischemia/reperfusion (I/R) rat model, we found that metformin could attenuate the deficits of hippocampal related behaviors and inhibit cell apoptosis. The western blot data showed that metformin could promote the activation of Akt1 and reduce the phosphorylation of JNK3 and c-Jun as well as elevation of cleaved caspase-3 in I/R brains. PI3K inhibitor reversed all the protective effects, further indicating that metformin protect hippocampus from ischemic damage through PI3K/Akt1/JNK3/c-Jun signaling pathway.


Subject(s)
Brain Ischemia/drug therapy , Brain Ischemia/enzymology , Metformin/pharmacology , Neuroprotective Agents/pharmacology , Reperfusion Injury/drug therapy , Reperfusion Injury/enzymology , Animals , Anxiety/drug therapy , Anxiety/enzymology , Anxiety/etiology , Anxiety/pathology , Apoptosis/drug effects , Apoptosis/physiology , Brain Ischemia/complications , Brain Ischemia/pathology , CA1 Region, Hippocampal/drug effects , CA1 Region, Hippocampal/enzymology , CA1 Region, Hippocampal/pathology , Caspase 3/metabolism , Cognition Disorders/drug therapy , Cognition Disorders/enzymology , Cognition Disorders/etiology , Cognition Disorders/pathology , Disease Models, Animal , Enzyme Inhibitors/pharmacology , Male , Maze Learning/drug effects , Maze Learning/physiology , Mitogen-Activated Protein Kinase 10/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Proto-Oncogene Proteins c-akt/metabolism , Pyramidal Cells/drug effects , Pyramidal Cells/enzymology , Pyramidal Cells/pathology , Rats, Sprague-Dawley , Reperfusion Injury/complications , Reperfusion Injury/pathology , Signal Transduction/drug effects
7.
Int J Clin Exp Pathol ; 8(6): 6126-34, 2015.
Article in English | MEDLINE | ID: mdl-26261490

ABSTRACT

BACKGROUND: Anastomotic leakage is one of serious complications of colorectal surgery. Research is inconsistent about whether non-steroidal anti-inflammatory drugs influence the healing of colorectal anastomoses and increase the incidence of anastomotic leakage. OBJECTIVE: To study the influence of NSAIDs on the healing of rat colonic anastomoses. DESIGN: This was an animal randomized-control trial. This study was approved by the ethical committee of Yangpu Hospital, Tongji University. INTERVENTION: 90 healthy Sprague-Dawley rats were randomly divided into 6 groups of 15 rats/group. Trail was performed in C (cotrol group) with no drugs, group M with morphine for analgesia, group F with flurbiprofen axeil, group L with lornoxicam, and group P with parecoxib sodium. MAIN OUTCOME MEASURES: The main outcomes measures were serological indexes including vascular endothelial growth factor, prostaglandin E2, hydroxyproline, and C reactive protein; histological specimens from the anastomotic stoma tissue including the collagen proportion, and hydroxyproline, cycloxygenase-2, and vascular endothelial growth factor content; physical indicators, including stoma fracture pressure, fracture strength and anastomotic leakage. RESULTS: No significant difference was observed among the indices of each group (P > 0.05). A significant difference occurred after operation (P < 0.05), with the data for groups K and M being dramatically higher than those for group F. LIMITATION: The study was nonblinded. CONCLUSION: The postoperative usages of non-steroidal anti-inflammatory drugs can decrease the strength of anastomotic tissue, and increase the incidence of anastomotic leakage.


Subject(s)
Anastomotic Leak/chemically induced , Anti-Inflammatory Agents, Non-Steroidal/toxicity , Colon/surgery , Wound Healing/drug effects , Anastomosis, Surgical/adverse effects , Anastomotic Leak/blood , Anastomotic Leak/pathology , Animals , Biomarkers/blood , C-Reactive Protein/metabolism , Collagen/metabolism , Colon/metabolism , Colon/pathology , Cyclooxygenase 2/metabolism , Dinoprostone/blood , Hydroxyproline/blood , Male , Models, Animal , Pressure , Rats, Sprague-Dawley , Risk Factors , Time Factors , Tissue Adhesions , Vascular Endothelial Growth Factor A/blood , Vascular Endothelial Growth Factor A/metabolism
8.
J Transl Med ; 13: 116, 2015 Apr 11.
Article in English | MEDLINE | ID: mdl-25889497

ABSTRACT

BACKGROUND: Genetic amplification of HER2 drives tumorigenesis and cancer progression in a subset of patients with gastric cancer (GC), and treatment with trastuzumab, a humanized HER2-neutralizing antibody, improves the overall survival rate of HER2-positive patients. However, a considerable portion of the patients does not respond to trastuzumab and the molecular mechanisms underlying the intrinsic resistance to anti-HER2 therapy in GC is not fully understood. METHODS: We performed whole-transcriptome sequencing on 21 HER2-positive tumor specimens from Chinese GC patients. Whole genome sequencing was performed on the three samples with HER2 fusion to discover the DNA integration structure. A multicolor FISH assay for HER2 split screening was conducted to confirm HER2 fusion and IHC (HercepTest™) was used to detect the membranous expression of HER2. Fusion cDNA were transfected into NIH/3T3 cells and generate stable cell line by lentivirus. The expression of exogenous HER2 fusion proteins and pHER2 were examined by western blot analysis. In vitro efficacy studies were also conducted by PD assay and softagar assay in cell line expression wild type and fusion HER2. T-DM1 was used to assess its binding to NIH/3T3 cells ectopically expressing wild-type and fusion HER2. Finally, the anti-tumor efficacy of trastuzumab was tested in NIH/3 T3 xenografts expressing the HER2 fusion variants. RESULTS: We identified three new HER2 fusions with ZNF207, MDK, or NOS2 in 21 HER2-amplified GC samples (14%; 3/21). Two of the fusions, ZNF207-HER2, and MDK-HER2, which are oncogenic, lead to aberrant activation of HER2 kinase. Treatment with trastuzumab inhibited tumor growth significantly in xenografts expressing MDK-HER2 fusion. In contrast, trastuzumab had no effect on the growth of xenografts expressing ZNF207-HER2 fusion, due to its inability to bind to trastuzumab. CONCLUSIONS: Our results provide the molecular basis of a novel resistance mechanism to trastuzumab-based anti-HER2 therapy, supporting additional molecule stratification within HER2-positive GC patients for more effective therapy options.


Subject(s)
Genes, erbB-2 , Oncogenes , Stomach Neoplasms/genetics , Animals , Base Sequence , DNA Primers , Gene Fusion , Humans , In Situ Hybridization, Fluorescence , Mice , NIH 3T3 Cells , Reverse Transcriptase Polymerase Chain Reaction
9.
Cancer Biol Ther ; 15(1): 128-34, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24253382

ABSTRACT

Protein phosphatase methylesterase 1 (PPME1) is a protein phosphatase 2A (PP2A)-specific methyl esterase that negatively regulates PP2A through demethylation at its carboxy terminal leucine 309 residue. Emerging evidence shows that the upregulation of PPME1 is associated with poor prognosis in glioblastoma patients. By performing an array comparative genomic hybridization analysis to detect copy number changes, we have been the first to identify PPME1 gene amplification in 3.8% (5/131) of Chinese gastric cancer (GC) samples and 3.1% (4/124) of Chinese lung cancer (LC) samples. This PPME1 gene amplification was confirmed by fluorescence in situ hybridization analysis and is correlated with elevated protein expression, as determined by immunohistochemistry analysis. To further investigate the role of PPME1 amplification in tumor growth, short-hairpin RNA-mediated gene silencing was employed. A knockdown of PPME1 expression resulted in a significant inhibition of cell proliferation and induction of cell apoptosis in PPME1-amplified human cancer cell lines SNU668 (GC) and Oka-C1 (LC), but not in nonamplified MKN1 (GC) and HCC95 (LC) cells. The PPME1 gene knockdown also led to a consistent decrease in PP2A demethylation at leucine 309, which was correlated with the downregulation of cellular Erk and AKT phosphorylation. Our data indicate that PPME1 could be an attractive therapeutic target for a subset of GCs and LCs.


Subject(s)
Carboxylic Ester Hydrolases/genetics , Lung Neoplasms/genetics , Stomach Neoplasms/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Apoptosis , Carboxylic Ester Hydrolases/metabolism , Carboxylic Ester Hydrolases/therapeutic use , Cell Line, Tumor , Female , Gene Dosage , Gene Expression Profiling , Humans , Lung Neoplasms/metabolism , Male , Middle Aged , RNA, Small Interfering/genetics , Signal Transduction , Stomach Neoplasms/metabolism , Young Adult
10.
J Transl Med ; 11: 241, 2013 Oct 02.
Article in English | MEDLINE | ID: mdl-24088382

ABSTRACT

INTRODUCTION: Activation of the PI3K/AKT pathway is a common phenomenon in cancer due to multiple mechanisms, including mutation of PI3KCA, loss or mutation of PTEN, or over-expression of receptor tyrosine kinases. We recently developed a novel AKT kinase inhibitor, AZD5363, and demonstrated that HGC27, a cell line harboring both PI3KCA mutation and PTEN loss, displayed the greatest sensitivity to this AKT inhibitor in vitro and in vivo. CASE PREPARATION: To further elucidate the correlation between AZD5363 response and genetic alterations in gastric cancer (GC) and identify GC patients with both PI3KCA mutations and PTEN loss, we investigated the effects of pharmacological inhibition of AKT on a panel of 20 GC cell lines and genetic aberrations in tumor samples from a cohort of Chinese GC patients. We demonstrated that GC cells with PI3KCA mutations were selectively sensitive to AZD5363. Disease linkage studies showed that PI3KCA activating mutations or PTEN loss were found in 2.7% (4/150) and 23% (14/61) of Chinese GC patients respectively. To further dissect the role of PI3KCA mutation and PTEN loss in response to AKT inhibition, we tested the antitumor activity of AZD5363 in two patient-derived GC xenograft (PDGCX) models harboring either PI3KCA mutation or PTEN loss. Our data indicated that AZD5363 monotherapy treatment led to a moderate response in the PI3KCA mutant PDGCX model. Whilst monotherapy AZD5363 or Taxotere were ineffective in the PTEN negative PDGCX model, significant anti-tumor activity was observed when AZD5363 was combined with Taxotere. CONCLUSION: Our results indicated that PI3KCA mutation is an important determinant of response to AKT inhibition in GC and combination with AZD5363 can overcome innate resistance to Taxotere in a PTEN loss PDGCX model. It is suggested that AKT inhibitor is an attractive option for treatment of a new segment of GC patients with aberrant PI3K/AKT signaling.


Subject(s)
Nuclear Proteins/genetics , PTEN Phosphohydrolase/deficiency , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyrimidines/therapeutic use , Pyrroles/therapeutic use , Stomach Neoplasms/drug therapy , Taxoids/therapeutic use , Transcription Factors/genetics , Xenograft Model Antitumor Assays , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Asian People , Cell Line, Tumor , Cell Proliferation/drug effects , China , Disease Models, Animal , Docetaxel , Female , Humans , Immunohistochemistry , Mice , Mice, Nude , Mutation/genetics , PTEN Phosphohydrolase/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins c-akt/metabolism , Pyrimidines/pharmacology , Pyrroles/pharmacology , Stomach Neoplasms/enzymology , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Taxoids/pharmacology , Treatment Outcome
11.
Mol Cancer Ther ; 11(4): 873-87, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22294718

ABSTRACT

AKT is a key node in the most frequently deregulated signaling network in human cancer. AZD5363, a novel pyrrolopyrimidine-derived compound, inhibited all AKT isoforms with a potency of 10 nmol/L or less and inhibited phosphorylation of AKT substrates in cells with a potency of approximately 0.3 to 0.8 µmol/L. AZD5363 monotherapy inhibited the proliferation of 41 of 182 solid and hematologic tumor cell lines with a potency of 3 µmol/L or less. Cell lines derived from breast cancers showed the highest frequency of sensitivity. There was a significant relationship between the presence of PIK3CA and/or PTEN mutations and sensitivity to AZD5363 and between RAS mutations and resistance. Oral dosing of AZD5363 to nude mice caused dose- and time-dependent reduction of PRAS40, GSK3ß, and S6 phosphorylation in BT474c xenografts (PRAS40 phosphorylation EC(50) ~ 0.1 µmol/L total plasma exposure), reversible increases in blood glucose concentrations, and dose-dependent decreases in 2[18F]fluoro-2-deoxy-D-glucose ((18)F-FDG) uptake in U87-MG xenografts. Chronic oral dosing of AZD5363 caused dose-dependent growth inhibition of xenografts derived from various tumor types, including HER2(+) breast cancer models that are resistant to trastuzumab. AZD5363 also significantly enhanced the antitumor activity of docetaxel, lapatinib, and trastuzumab in breast cancer xenografts. It is concluded that AZD5363 is a potent inhibitor of AKT with pharmacodynamic activity in vivo, has potential to treat a range of solid and hematologic tumors as monotherapy or a combinatorial agent, and has potential for personalized medicine based on the genetic status of PIK3CA, PTEN, and RAS. AZD5363 is currently in phase I clinical trials.


Subject(s)
Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyrimidines/pharmacology , Pyrroles/pharmacology , Animals , Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Cell Line, Tumor , Cell Proliferation , Female , Humans , Male , Mice , Mice, Nude , Mice, SCID , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/enzymology , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Xenograft Model Antitumor Assays
12.
Planta Med ; 77(2): 141-5, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20717870

ABSTRACT

The involvement of unfolded protein response (UPR) activation in tumor survival and resistance to chemotherapies suggests a new anticancer strategy targeting UPR pathway. Arctigenin, a natural product, has been recently identified for its antitumor activity with selective toxicity against cancer cells under glucose starvation with unknown mechanism. Here we found that arctigenin specifically blocks the transcriptional induction of two potential anticancer targets, namely glucose-regulated protein-78 (GRP78) and its analog GRP94, under glucose deprivation, but not by tunicamycin. The activation of other UPR pathways, e.g., XBP-1 and ATF4, by glucose deprivation was also suppressed by arctigenin. A further transgene experiment showed that ectopic expression of GRP78 at least partially rescued arctigenin/glucose starvation-mediated cell growth inhibition, suggesting the causal role of UPR suppression in arctigenin-mediated cytotoxicity under glucose starvation. These observations bring a new insight into the mechanism of action of arctigenin and may lead to the design of new anticancer therapeutics.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Furans/pharmacology , Glucose/metabolism , Lignans/pharmacology , Transcriptional Activation/drug effects , Unfolded Protein Response/drug effects , Activating Transcription Factor 4/drug effects , Activating Transcription Factor 4/genetics , Animals , Cell Line, Tumor , Cell Survival/drug effects , DNA-Binding Proteins/drug effects , DNA-Binding Proteins/genetics , Endoplasmic Reticulum Chaperone BiP , Gene Expression Regulation, Neoplastic/drug effects , Glucose/pharmacology , HSP70 Heat-Shock Proteins/drug effects , HSP70 Heat-Shock Proteins/genetics , Humans , Membrane Proteins/drug effects , Membrane Proteins/genetics , Regulatory Factor X Transcription Factors , Time Factors , Transcription Factors/drug effects , Transcription Factors/genetics , Unfolded Protein Response/genetics , X-Box Binding Protein 1
14.
PLoS One ; 3(12): e3951, 2008.
Article in English | MEDLINE | ID: mdl-19079611

ABSTRACT

We identified pyrvinium pamoate, an old anthelminthic medicine, which preferentially inhibits anchorage-independent growth of cancer cells over anchorage-dependent growth (approximately 10 fold). It was also reported by others to have anti-tumor activity in vivo and selective toxicity against cancer cells under glucose starvation in vitro, but with unknown mechanism. Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187. Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium. Constitutive expression of GRP78 via transgene partially protected cells from pyrvinium induced cell death under glucose starvation, suggesting that suppression of the UPR is involved in pyrvinium mediated cytotoxicity under glucose starvation. Xenograft experiments showed rather marginal overall anti-tumor activity for pyrvinium as a monotherapy. However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.


Subject(s)
Antineoplastic Agents/pharmacology , Antineoplastic Combined Chemotherapy Protocols , Hypoglycemia/metabolism , Protein Folding/drug effects , Pyrvinium Compounds/pharmacology , Activating Transcription Factor 4/metabolism , Animals , Cell Adhesion/drug effects , Cell Death/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Down-Regulation/drug effects , Doxorubicin/pharmacology , Drug Synergism , Endoplasmic Reticulum Chaperone BiP , Female , Gene Expression Regulation, Neoplastic/drug effects , Glucose/deficiency , Glycolysis/drug effects , HSP70 Heat-Shock Proteins/genetics , HSP70 Heat-Shock Proteins/metabolism , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Humans , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Nude , Molecular Chaperones/genetics , Molecular Chaperones/metabolism , Regulatory Factor X Transcription Factors , Transcription Factors/genetics , Transcription Factors/metabolism , Transcriptional Activation/drug effects , Up-Regulation/drug effects , X-Box Binding Protein 1
15.
Biochem Biophys Res Commun ; 366(2): 314-20, 2008 Feb 08.
Article in English | MEDLINE | ID: mdl-18042463

ABSTRACT

Bilateral frontoparietal polymicrogyria (BFPP) is a rare genetic disease characterized by cortical malformation associated with GPR56 mutations of frameshift, splicing, and point mutations (Science 303:2033). All the missense point mutations are located in the regions predicted to be exposed at the cell surface, e.g. the N-terminal extracellular domain (ECD), the proteolytic site (GPS), and the extracellular loops of transmembrane domain (TM), implying functionally important interaction among these domains. Wild type GPR56 protein is cleaved at the GPCR protein cleavage site (GPS) and gives rise to two subunits (ECD and TM), which are transported to cell surface. We have shown that GPR56 GPS mutant protein is defective in cleavage and surface localization, while non-GPS mutant proteins are cleaved normally but still defective in surface localization. Furthermore, all the mutant proteins demonstrated different glycosylation pattern from that of wild-type protein. PNGase F and Endo H sensitivity assays suggests that the mutant proteins are trapped in endoplasmic reticulum (ER), preventing them from trafficking to Golgi where further glycosylation modification usually occurs before destination to cell surface. Therefore, the loss-of-function of all these missense mutations is primarily caused by their failure to localize to cell surface.


Subject(s)
Cell Membrane/chemistry , Cell Membrane/metabolism , Malformations of Cortical Development/genetics , Malformations of Cortical Development/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Animals , Genetic Predisposition to Disease/genetics , Humans , Mice , Mutation , NIH 3T3 Cells , Receptors, G-Protein-Coupled/chemistry
16.
Invest New Drugs ; 24(6): 489-98, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16633716

ABSTRACT

4-Methyl-2,7-diamino-5,10-diphenyl-4,9-diaz-apyrenium chloride (MDDD), a stable and water soluble nucleic acid-intercalating agent, was shown to be toxic to cancer cells with IC50 around 10 microM. IC(50) We tested MDDD for its potential antitumor activities and found it inhibited cancer cell growth with IC(50) in the micromolar range for the majority of cancer cells tested, with the exception of glioma cells, for which the IC(50) is in the submicromolar range. This unique selectivity of MDDD to glioma cells can potentially be exploited for anti-glioma therapeutics. Although the underlying mechanisms for the apparent glioma specificity remain to be elucidated, our analysis indicates that MDDD significantly reduces cell clonogenicity and blockes cell proliferation at the G1 phase. MDDD treatment also triggers induction of p53 and p21 at the protein levels, suggesting the activation of DNA damage response. However, MDDD mediated growth inhibition does not require the p53 pathway since p53+/- isogenic cell pairs display the same sensitivity. These properties of MDDD favor its candidacy for evaluation as a new anti-tumor agent, particularly for glioma.


Subject(s)
Antineoplastic Agents/pharmacology , Cell Cycle/drug effects , Glioma/pathology , Intercalating Agents/pharmacology , Pyridinium Compounds/pharmacology , Animals , Apoptosis , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , DNA/drug effects , DNA/metabolism , DNA Damage , G1 Phase , Glioma/genetics , Glioma/metabolism , Humans , Inhibitory Concentration 50 , Neoplastic Stem Cells/drug effects , RNA Interference , Rats , Resting Phase, Cell Cycle , Tumor Stem Cell Assay , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
17.
Exp Cell Res ; 312(6): 865-76, 2006 Apr 01.
Article in English | MEDLINE | ID: mdl-16413018

ABSTRACT

HeLaHF is a non-transformed revertant of HeLa cells, likely resulting from the activation of a putative tumor suppressor(s). p53 protein was stabilized in this revertant and reactivated for certain transactivation functions. Although p53 stabilization has not conclusively been linked to the reversion, it is clear that the genes in p53 pathway are involved. The present study confirms the direct role of p53 in HeLaHF reversion by demonstrating that RNAi-mediated p53 silencing partially restores anchorage-independent growth potential of the revertant through the suppression of anoikis. In addition, we identified a novel gene, named PHTS, with putative tumor suppressor properties, and showed that this gene is also involved in HeLaHF reversion independently of the p53 pathway. Expression profiling revealed that PHTS is one of the genes that is up-regulated in HeLaHF but not in HeLa. It encodes a putative protein with CD59-like domains. RNAi-mediated PHTS silencing resulted in the partial restoration of transformation (anchorage-independent growth) in HeLaHF cells, similar to that of p53 gene silencing, implying its tumor suppressor effect. However, the observed increased transformation potential by PHTS silencing appears to be due to an increased anchorage-independent proliferation rate rather than suppression of anoikis, unlike the effect of p53 silencing. p53 silencing did not affect PHTS gene expression, and vice versa, suggesting PHTS may function in a new and p53-independent tumor suppressor pathway. Furthermore, over-expression of PHTS in different cancer cell lines, in addition to HeLa, reduces cell growth likely via induced apoptosis, confirming the broad PHTS tumor suppressor properties.


Subject(s)
Transformation, Genetic , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/physiology , Tumor Suppressor Proteins/metabolism , Amino Acid Sequence , Cell Line, Tumor , Cell Proliferation , Cell Survival/physiology , GPI-Linked Proteins , Gene Expression Profiling , Gene Silencing , HeLa Cells , Humans , Membrane Proteins , Molecular Sequence Data , Phenotype , RNA Interference/physiology , Tumor Suppressor Proteins/genetics , Up-Regulation
19.
Assay Drug Dev Technol ; 3(4): 401-11, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16180995

ABSTRACT

Transient transfection of short interfering RNAs to inactivate cancer therapeutic genes in cancer cells is an important method to induce therapeutic phenotypes (cell apoptosis, growth arrest, etc.) for cancer target validation. These phenotypes can be initially assessed by cell survival via colorimetric/fluorescence readings, e.g., alamarBlue (Trek Diagnostic Systems, Cleveland, OH) and WST-1. However, intrinsic problems exist for transient transfection-varying toxicity, inconsistent transfection efficiency, as well as other cell-specific determinants-which contribute to a low signal:noise ratio of the assays, rendering of the assay ineffective particularly when applied in high-throughput screening (HTS) multiplexed for different cells. This report describes a method using reporter as a "normalized surrogate" for the conventional survival readout in a 96-well format. In this approach, only the transfected surviving cells produce reporter activities, and many variables associated with transient transfection are excluded. A constitutively expressed reporter gene (luciferase or LacZ) expression cassette is co-transfected into cells along with a specially designed RNA interference (RNAi) vector (or a transgene for that matter). The reporter activity in either liquid cultures or in soft agar cultures in 96-well formats is then quantitated in situ. The RNAi vector construction is simplified so that it can be adapted to a 96-well format. Our data demonstrated that the relative reporter readings for survival are independent of both transfection efficiency and cellular toxicity. The signal:noise ratio is markedly increased, particularly for cells with low transfection efficiency. The assay is versatile and robust and can be applied in multiplexed HTS for cancer target identification and validation.


Subject(s)
Genes, Reporter , Genetic Vectors , RNA, Small Interfering/genetics , Base Sequence , Cell Survival , Drug Evaluation, Preclinical/methods , HeLa Cells , Humans , Indicators and Reagents , Luciferases/genetics , Luciferases/metabolism , Molecular Sequence Data , Oxazines , Proto-Oncogenes/genetics , RNA Interference , RNA, Messenger , RNA, Small Interfering/metabolism , Transfection , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolism , Xanthenes , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolism
20.
Cancer Res ; 64(22): 8208-12, 2004 Nov 15.
Article in English | MEDLINE | ID: mdl-15548686

ABSTRACT

HeLaHF cells are transformation revertants of cervical cancer HeLa cells and have lost anchorage-independent growth potential and tumorigenicity. Activation of tumor suppressor(s) was implicated previously in this transformation reversion. In this study, expression profiling analysis was carried out to identify potential oncogenes that are down-regulated in HeLaHF cells. We found that all three members of the NR4A1/Nur77/NGFIB orphan nuclear hormone receptor subfamily (NR4A1, NR4A2, and NR4A3) were down-regulated in the HeLaHF revertant. Small interfering RNA-mediated down-regulation of NR4A2 in HeLa cells, either transiently or stably, resulted in reduced anchorage-independent growth that was largely attributable to increased anoikis. Furthermore, down-regulation of NR4A2 as well as NR4A1 promoted intrinsic apoptosis. These phenotypes were also observed in several other experimental cancer cells, suggesting the observed apoptosis suppression is a more general property of NR4A2 and NR4A1. These phenotypes also suggest that the Nur77/NGFIB subfamily of orphan receptors exhibit certain oncogenic functionalities with regards to cell proliferation and apoptosis and could therefore be evaluated as potential cancer therapeutic targets.


Subject(s)
Apoptosis/physiology , Cell Transformation, Neoplastic , DNA-Binding Proteins/physiology , Transcription Factors/physiology , Down-Regulation , HeLa Cells , Humans , Nuclear Receptor Subfamily 4, Group A, Member 2 , RNA, Small Interfering
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