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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small interfering RNAs (siRNAs) are potentially powerful tools for therapeutic gene regulation. DNA cassettes encoding RNA polymerase III promoter-driven hairpin siRNAs allow long-term expression of siRNA in targeted cells. A variety of viral vectors have been used to deliver such cassettes to cells. Here we report on the development and use of a self-complementary recombinant adeno-associated virus (scAAV) vector for siRNA delivery into mammalian cells. We demonstrate that this modified vector efficiently delivers siRNA into multidrug-resistant human breast and oral cancer cells and suppresses MDR1 gene expression. This results in rapid, profound, and durable reduction in the expression of the P-glycoprotein multidrug transporter and a substantial reversion of the drug-resistant phenotype. This research suggests that scAAV-based vectors can be very effective agents for efficient delivery of therapeutic siRNA.
Mol Ther 2005 Apr
PMID:Delivery of MDR1 small interfering RNA by self-complementary recombinant adeno-associated virus vector. 1577 55

An early interventional effort in oral premalignancy requires novel molecular targets and diagnostic biomarkers to delay or reverse incidences of malignant progression. Microarray-based transcriptional profiling in disease states provides global insight into the causal biomolecular processes and novel pathways involved. In this study, we investigated transcript profiles in precancerous oral lesions to identify nearly 1,700 genes as significantly overexpressed or underexpressed and a primarily affected metabolic pathway that may be responsible for irreversible transition to progressive stages of oral cancer. For the first time, we show a convergence of several genes and pathways known for their oncogenic capabilities, in progression of premalignant oral epithelial tissues. This study consequently provides a molecular basis for persistent proinflammatory conditions in oral premalignant tissues. We found that lipocalin-type prostaglandin D(2) synthase (PTGDS), a key enzyme in the arachidonic acid metabolism pathway, as repressed in premalignant stages. We show the protective role of these enzyme-derived metabolites in inhibiting cell proliferation using an in vitro oral cancer progression model. We have also confirmed the overexpression of two invasion-related biomarkers, psoriasin (PSOR1) and versican (CSPG2), in oral premalignant and malignant archival tissues. Our results clearly indicate that pharmacologic intervention with anti-inflammatory prostaglandin D(2)-like analogues may help prevent or delay oral epithelial carcinogenesis because of metabolic restoration of a negative feedback regulatory loop through its several cognate receptors or target molecules. Further studies directed toward a multitude of possible protective mechanisms of this lipocalin-type enzyme or its products in oral cancer progression are warranted.
Mol Cancer Ther 2005 Jun
PMID:Identification of genes and molecular pathways involved in the progression of premalignant oral epithelia. 1595 44

Telomerase activity is suppressed in normal human somatic tissues but is activated in cancer cells and immortal cell lines. The reverse transcriptase (RT) subunit human telomerase reverse transcriptase (hTERT) is the key regulator of telomerase activity. The hTERT promoter contains E-box elements and may allow upstream stimulatory factor (USF), a basic helix-loop-helix (bHLH) leucine zipper family proteins, to bind and regulate the expression. In this study, we investigated whether and how USF effect on hTERT. Through luciferase reporter assays, we found that both USF1 and USF2 possess a comparable effect on the inhibition of hTERT expression. Immunoprecipitation (IP) and immunoblotting (IB) analysis reveal that the suppression of hTERT by USF was not through the interaction of USF with c-myc or mad, nor disturbed the cellular protein levels of those. In gel mobility shift and chromatin immunoprecipitation (CHIP) assays, we found that the USF suppression is through direct binding at the E-box site of hTERT promoter and rendering the effect actively. Analysis on clinical normal and tumor tissues reveal that the expression of USF1 and USF2 was lower in the tumor tissues, correlated with hTERT expression and telomerase activity. Taking together, our results demonstrate that USF is a negative transcriptional repressor for hTERT in oral cancer cells. It is possible that USF lose the inhibitory effect on hTERT expression leading to telomerase reactivation and oral carcinogenesis.
Mol Carcinog 2005 Nov
PMID:Upstream stimulatory factor (USF) as a transcriptional suppressor of human telomerase reverse transcriptase (hTERT) in oral cancer cells. 1601 Jun 90

Oral squamous cell carcinomas (OSCCs), a major public health problem worldwide, are the most common neoplasms of the head and neck. The most important prognostic indicator for patients with OSCC is metastasis to cervical lymph nodes or distant organs. Galectin-9 is correlated with cellular adhesion and aggregation in melanoma cells. To investigate expression levels of galectin-9 mRNA and protein, we performed qRT-PCR and Western blot analyses on OSCC cell lines (Ca9-22, HSC-2, and HSC-3) and normal oral keratinocytes (NOKs). Galectin-9 mRNA and protein were commonly down-regulated in OSCC cell lines compared with NOKs. We further analyzed Ca9-22, which had the lowest expression of galectin-9. We then transfected the galectin-9 cDNA into Ca9-22 cells to examine whether overexpression of galectin-9 increases cellular adhesion in vitro. An adhesion assay using a fibronectin and collagen I coating plate revealed an increased cellular adherence ratio in overexpressed galectin-9 cells compared with nontransfected cells (p < 0.05). The data suggest that galectin-9 is correlated with oral cancer cell-matrix interactions and may therefore play an important role in the metastasis of OSCCs.
Int J Mol Med 2005 Aug
PMID:Galectin-9 as a regulator of cellular adhesion in human oral squamous cell carcinoma cell lines. 1601 60

Cyclin D1 overexpression and upregulation has been reported largely in Oral Squamous Cell Carcinoma (OSCC) but the mechanism behind it is not clear. Here, the transcription and translational upregulation of cyclin D1 was observed in most of the tobacco chewing oral cancer patients where as the gene amplification was limited to only small group (20%) of patients. A transcription factor (TF) binding site has been detected from -483 to -451 by using DNase I foot printing analysis and confirmed by electrophoretic mobility shift assay by using oral tumour nuclear extract (NE). This is a STAT binding sequence and confirmed as STAT 5a by super shift assay. The binding of STAT 5 was observed in 80% (24/30) oral cancer samples. The co-expression of cyclin D1 with STAT 5 binding was observed in 90% (27/30) of the samples. STAT family of proteins is emerging to play role in oral carcinogenesis. Here, the binding of STAT 5 might up regulate cyclin D1 in most of the samples whereas; the gene amplification events are sporadic in oral carcinogenesis. Our study provides the first evidence of the constitutive activation of STAT 5-cyclin D1 pathway in chewing tobacco mediated OSCC.
Mol Biol Rep 2005 Sep
PMID:Activation of STAT 5-cyclin D1 pathway in chewing tobacco mediated oral squamous cell carcinoma. 1617 16

Cationic lipids and polyamines have been used as non-viral gene transfer reagents, both in vitro and in vivo. One of the limitations to their use in vivo is the inhibition of gene delivery by serum. We showed previously that, in the absence of serum, relatively high cytotoxicity in oral cancer cell lines could be achieved via transfection of the Herpes Simplex Virus thymidine kinase (HSV-tk) gene followed by treatment with ganciclovir (GCV), despite the low efficiency of transfection (Konopka et al., Gene Ther. Mol. Biol. 8 (2004) 307-318). In this study we evaluated the effect of high concentrations (20-60%) of fetal bovine serum (FBS) on the transfection efficiency of two novel reagents, the polycationic liposome, Metafectene, and the polyamine reagent, GeneJammer, in HSC-3 and H357 human oral squamous cell carcinoma (OSCC) cells. We also examined whether the HSV-tk gene delivered in the presence of FBS (up to 60%, could induce cell death following treatment with GCV. Transfection was optimized using a luciferase-expressing plasmid. Both Metafectene- and GeneJammer-mediated luciferase gene expression in HSC-3 cells was reduced by 40-50% when transfection was performed in the presence of 20-60% FBS. The delivery of the HSV-tk gene by Metafectene in the absence and the presence of 60% FBS, followed by GCV treatment for 9 days, resulted in 95% and 70% cytotoxicity, respectively. With GeneJammer, transfection in 0% and 60% FBS resulted in 90% and 40% cytotoxicity, respectively, after 9 days. In contrast, very low transfection activity and a much higher inhibitory effect of serum were observed in H357 cells. Nevertheless, about 35% GCV-mediated cytotoxicity was observed with H357 cells at both 0% and 60% FBS, using GeneJamer. Thus, Metafectene and GeneJammer can be used in the delivery of genes in biological milieu and in the gene therapy of OSCC in animal models.
Cell Mol Biol Lett 2005
PMID:Serum-resistant gene transfer to oral cancer cells by Metafectene and GeneJammer: application to HSV-tk/ganciclovir-mediated cytotoxicity. 1621 56

Since genetic abnormalities of human cancer are greatly geographically dependent, cultural and environmental backgrounds are thought to be closely related to the carcinogenic process. In the present study, eight human cell lines were established by culture from untreated carcinomas of the oral cancer, of which five were from primary oral squamous cell carcinomas (OSC), one from a mucoepidermoid carcinoma (MEC) and one each originating from metastatic OSC and MEC. All the studied tumor lines grew as monolayers, and showed: i) an epithelial origin by the presence of cytokeratin, and ii) tumorigenic potential in nude mice. Western blot analysis revealed i) over expression of EGFR in six of the cell lines ii) decreased expression of E-cadherin in six cell lines compared to normal human oral mucosa. A mutational analysis showed: point mutations of p53 at exon 7, with transversion, and at exon 8, with transition. These well-characterized human YD cell lines should serve as useful tools in the study of the molecular pathogenesis and biological characteristics of head and neck cancer cells, and in the future testing of new therapeutic reagents for oral cancer.
Exp Mol Med 2005 Oct 31
PMID:Characterization of newly established oral cancer cell lines derived from six squamous cell carcinoma and two mucoepidermoid carcinoma cells. 1626 62

Early detection of a premalignant or cancerous oral lesion promises to improve the survival and the morbidity of patients suffering from these conditions. Cytological study of oral cells is a non-aggressive technique that is well accepted by the patient, and is therefore an attractive option for the early diagnosis of oral cancer, including epithelial atypia and squamous cell carcinoma. However its usage has been limited so far due to poor sensitivity and specificity in diagnosing oral malignancies. Lately it has re-emerged due to improved methods and it's application in oral precancer and cancer as a diagnostic and predictive method as well as for monitoring patients. Newer diagnostic techniques such as "brush biopsy" and molecular studies have been developed. Recent advances in cytological techniques and novel aspects of applications of scraped or exfoliative cytology for detecting these lesions and predicting their progression or recurrence are reviewed here.
Mol Cancer 2006 Mar 23
PMID:Application of cytology and molecular biology in diagnosing premalignant or malignant oral lesions. 2290 81

Aim-To study p53 expression in relation to proliferative status in normal and nondysplastic, dysplastic and malignant lesions of the oral mucosa.Method-The standard avidin-biotin complex (ABC) immunohistochemical staining method was used to study the expression of p53 and Ki67 on frozen sections of oral leukoplakias and carcinomas.Results-Of the leukoplakia and carcinoma samples, 70% expressed p53 in over 5% of cells. In normal mucosa less than 5% of cells expressed p53. The proliferation index, as assessed by expression of Ki67, was highest in the malignant lesions (43%) and lowest in normal mucosa (11%). Statistical analysis revealed that expression of both p53 and Ki67 was correlated significantly with the histopathological stage of the tumour. However, expression of p53 was not correlated with that of Ki67. In leukoplakia lesions with proliferative features p53 immunostaining was less intense than in non-proliferative lesions; this difference was statistically significant.Conclusions-These results emphasise the potential of Ki67 and p53 as biomarkers of carcinogenesis in oral cancer and may also serve as intermediate points for cancer prevention programmes, such as the oral chemopreventive trials. Factors other than p53 may have a more important role in the deregulation of proliferation in pre-malignant oral lesions.
Clin Mol Pathol 1996 Jun
PMID:Expression of p53 in leukoplakia and squamous cell carcinoma of the oral mucosa: correlation with expression of Ki67. 1669 67

Oral cancer is a major health problem in many parts of the world including India. The molecular mechanisms involved in oral tumorigenesis are not completely understood. Although surgery continues to be the most common treatment modality for this cancer, survival rates of oral cancer patients have still not significantly improved over the last few decades. Classical diagnostic methods are still not sensitive enough in detecting completeness of surgery and assessing minimal residual disease. This study investigated the role of NF-kappaB and COX-2 both in oral cancer progression and assessment of minimal residual disease. Expression of NF-kappaB proteins and its inhibitory protein IkappaB-alpha was evaluated using immunohistochemistry, ELISA and EMSA, while RT-PCR was used to detect COX-2 expression. Cytoplasmic expression as well as nuclear translocation of NF-kappaB proteins increased with histological progression of oral cancer (from normal to leukoplakia to cancer). A similar pattern of expression was observed for COX-2 also. NF-kappaB proteins, both cytoplasmic and nuclear, had a significant negative correlation from tumor to surgical margin to extra margin; COX-2 paralleled the expression of NF-kappaB proteins. Our results thus point to NF-kappaB and COX-2 as participants in oral tumor progression and also to the validation of these two molecular markers in assessing minimal residual disease.
Exp Mol Pathol 2006 Oct
PMID:NF-kappaB and COX-2 during oral tumorigenesis and in assessment of minimal residual disease in surgical margins. 1682


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