ABSTRACT
In this study, cepharanthine hydrochloride (CH) was tested for its potential ability to modulate the expression and function of P-glycoprotein (P-gp) in the multidrug-resistant human chronic myelogenous leukemia cell line K562/ADR. Cytotoxicity of adriamycin (ADR) alone or in combination with CH or verapamil (VER) in K562 and K562/ADR cells was determined by MTT assay. Based on flow cytometric technology, the effect of CH or VER on the uptake and efflux of rhodamine123 (Rho123) and the accumulation of ADR in these cells was detected by measuring Rho123 or ADR-associated mean fluorescence intensity (MFI). The effects of CH and VER on P-glycoprotein (P-gp) expression in K562 and K562/ADR cells were also measured using a flow cytometry with PE-conjugated P-glycoprotein antibody. The results show that CH significantly enhanced the sensitivity of K562/ADR cells to ADR, 4 micromol x L(-1) of CH enhanced the sensitivity of K562/ADR cells to ADR by 7.43 folds, the reversal activity was 3.19 times higher than that of verapamil. However, CH had no effect on drug-sensitive K562 cells (P < 0.05). CH increased Rho123 and ADR accumulation in a concentration-dependent manner (2-8 micromol x L(-1)) and inhibited the efflux of Rho123 from these cells, but did not affect the accumulation and efflux of Rho123 from the wild-type drug-sensitive K562 cells. The inhibition effect of CH on P-gp expression in K562/ADR cells is in a time- and concentration-dependent manner. The reversal activity of CH is possibility related to inhibition of P-gp function and expression, which lead to an increased intracellular accumulation of anticancer drugs.
Subject(s)
Humans , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Metabolism , Antibiotics, Antineoplastic , Metabolism , Pharmacology , Antineoplastic Agents, Phytogenic , Pharmacology , Benzylisoquinolines , Pharmacology , Dose-Response Relationship, Drug , Doxorubicin , Metabolism , Pharmacology , Drug Resistance, Multiple , Drug Resistance, Neoplasm , K562 Cells , Rhodamine 123 , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To study the expressions of Piwil2 protein and mRNA in papillary thyroid carcinoma (PTC) and the relationship between Piwil2 and the invasion and metastasis of PTC.</p><p><b>METHODS</b>Immunohistochemistry and in situ hybridization were used to detect the expression of Piwil2 protein and mRNA in 60 cases of PTC with the matched adjacent non-cancerous epithelium (NCE).</p><p><b>RESULTS</b>The positive rates of Piwil2 protein expression in PTC and NCE were 88.3% (53/60) and 10.0% (6/60) respectively, with significant difference (χ² = 73.654, P < 0.01). The positive rates of Piwil2 mRNA expression in PTC and NCE were 85.0% (51/60) and 6.7% (4/60) respectively, also with significant difference (χ(2) = 74.148, P < 0.01). Up-regulated expressions of Piwil2 protein and mRNA were related to the invasion and metastasis of PTC (P < 0.05).</p><p><b>CONCLUSIONS</b>Piwil2 may play a role in the invasion and metastasis of PTC.</p>
Subject(s)
Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Young Adult , Argonaute Proteins , Carcinoma , Carcinoma, Papillary , Lymphatic Metastasis , Proteins , Genetics , Metabolism , RNA, Messenger , Genetics , Thyroid Neoplasms , Metabolism , PathologyABSTRACT
<p><b>OBJECTIVE</b>To study the relationship between status of methylation of human runt-related transcription factor 3 (RUNX3) gene promoter in papillary thyroid carcinoma (PTC).</p><p><b>METHODS</b>Methylation-specific PCR and immunohistochemical SP technique were used to detect the methylation of RUNX3 gene promoter and expression of its protein in 56 cases of PTC and their matched adjacent non-carcinous epithelium (NCE).</p><p><b>RESULTS</b>In NCE, there was no methylation of RUNX3 gene promoter, while in PTC the methylation rate was 35.7%(20/56), which was related to the tumor TNM stage, pathological grade and lymph node metastasis (P < 0.05). The positive rates of RUNX3 protein expression in NCE and PTC were 100.0% and 60.7%, respectively, with a significant difference (χ(2) = 27.378, P < 0.05). In PTC, the positive rates of RUNX3 protein expression in gradeI and grade II were 70.0% and 37.5%, respectively (P < 0.05); the rates were 46.7% and 76.9% in lymph node metastasis group and no metastasis group, respectively (P < 0.05). Moreover, there was a distinct correlation between methylation of RUNX3 gene promoter and expression of its protein (χ(2) = 21.62, P < 0.01).</p><p><b>CONCLUSIONS</b>Methylation of promoter might be one of the important factors of inactivation of RUNX3 gene, and might play an important role in carcinogenesis and progression of PTC.</p>
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Carcinoma , Carcinoma, Papillary , Core Binding Factor Alpha 3 Subunit , Genetics , Metabolism , DNA Methylation , Promoter Regions, Genetic , RNA, Messenger , Genetics , Thyroid Neoplasms , Metabolism , PathologyABSTRACT
Aflatoxins produced primarily by two closely related fungi, Aspergillus flavus and Aspergillus parasiticus, are mutagenic and carcinogenic in animals and humans. Of many approaches investigated to manage aflatoxin contamination, biological control method has shown great promise. Numerous organisms, including bacteria, yeasts and nontoxigenic fungal strains of A. flavus and A. parasiticus, have been tested for their ability in controlling aflatoxin contamination. Great successes in reducing aflatoxin contamination have been achieved by application of nontoxigenic strains of A. flavus and A. parasiticus in fields of cotton, peanut, maize and pistachio. The nontoxigenic strains applied to soil occupy the same niches as the natural occurring toxigenic strains. They, therefore, are capable of competing and displacing toxigenic strains. In this paper, we review recent development in biological control of aflatoxin contamination.
Subject(s)
Animals , Humans , Aflatoxins , Toxicity , Aspergillus , Virulence , Physiology , Aspergillus flavus , Virulence , Physiology , Food Contamination , Herbicides , Pest Control, Biological , Methods , Soil Microbiology , Species SpecificityABSTRACT
The AtTOM1 gene of Arabidopsis thaliana had been shown to be essential for the efficient multiplication of Tobacco mosaic virus (TMV) in A. thaliana. In this study, we cloned an AtTOM1-like gene from Nicotiana benthamiana named as NbTOM1. Sequence alignment showed that NbTOM1 is closely related to AtTOM1 homologues of N. tabacum and Lycopersicon esculentum with 97.2% and 92.6% nucleotide sequence identities, respectively. Silencing of NbTOM1 by a modified viral satellite DNA-based vector resulted in complete inhibition of the multiplication of TMV in N. benthamiana. The result suggests that inhibition of NbTOM1 via RNA silencing is a potentially useful method for generating TMV-resistant plants.
Subject(s)
Arabidopsis Proteins , Genetics , Cloning, Molecular , Membrane Proteins , Genetics , Plant Proteins , Genetics , RNA Interference , RNA, Plant , RNA, Viral , Sequence Homology , Nicotiana , Metabolism , Virology , Tobacco Mosaic Virus , Physiology , Virus ReplicationABSTRACT
<p><b>AIM</b>To investigate the correlation between reversal effect of cepharanthine hydrochloride (CH) on multidrug resistance (MDR) in drug-resistant cell line EAC/ADR and the nuclear transcription factor-KB (NF-KB).</p><p><b>METHODS</b>Cytotoxicity was determined by the tetrazolium (MTT) assay in vitro. An EAC/ADR cell homograft model was established to investigate the effect of CH on reversing MDR in vivo. The constitutive activity and activation of NF-KB by drugs were measured by Dot-Enzyme-linked Immune Sorbent Assay (Dot-ELISA).</p><p><b>RESULTS</b>CH was shown to potentiate the cytotoxicity of ADR, a 13- fold reversal effect of resistance was achieved in vitro. In mice bearing EAC/ADR cell homografts, CH was found to prolong the survival time of animals bearing tumor. Increase in life span over control was 75. 37%. In addition, the constitutive activity of NF-KB and activation of NF-KB by chemotherapy were lowered by CH.</p><p><b>CONCLUSION</b>The findings suggest that CH is able to reverse drug resistance and its mechanism may be related to suppressing the constitutive activity and activation of NF-KB by drugs.</p>