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 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
<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>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>
Subject(s)
Animals , Female , Male , Mice , Alkaloids , Pharmacology , Antineoplastic Agents, Phytogenic , Pharmacology , Benzylisoquinolines , Carcinoma, Ehrlich Tumor , Drug Therapy , Metabolism , Pathology , Cell Line, Tumor , Drug Resistance, Multiple , Drug Resistance, Neoplasm , NF-kappa B , Metabolism , Neoplasm Transplantation , Plant Roots , Chemistry , Plants, Medicinal , Chemistry , Random Allocation , Stephania , ChemistryABSTRACT
<p><b>AIM</b>To investigate the effect of oridonin (ORI) on telomerase activity and cell cycle of human leukemic cell line K562 cells.</p><p><b>METHODS</b>Immunohistochemistry (IHC) technique was used to determine the expression of hTERT or C-myc. Telomerase activity was detected with TRAP-PCR-ELISA assay. In addition, the percentages of K562 cells in different cell cycle were determined by flow cytometry (FCM) at 24th and 48th hours separately after adding the different concentrations of ORI.</p><p><b>RESULTS</b>After the K562 cells were treated with ORI at 3.43 micromol x L(-1) for 48 h, the expression of hTERT and C-myc decreased obviously. There was statistical significant (P < 0.05) difference between experimental groups and the normal controls. In addition, the telomerase activity of K562 cells was significantly inhibited by ORI at the dose of 3.43 micromol x L(-1) for 48 h. At the same time, the cell cycle distribution changed, the percentage of G0/G1 or G2/M stages cells increased and that of the S stage cells decreased after ORI was added.</p><p><b>CONCLUSION</b>ORI can effectively inhibit telomerase activity in K562 cells. Arresting cell cycle and decreasing the expression of hTERT and C-myc may be the mechanism of action.</p>