RESUMO
<p><b>OBJECTIVE</b>To investigate the effects of curcumin (Cur) and erythromycin (EM) on multidrug resistance (MDR) reversal of K562/A02 cell line and their mechanism.</p><p><b>METHODS</b>MTT assay was employed to determine the sensitivity of Cur, EM-treated K562/A02 cells to adriamycin (ADM). Flow cytometry was used to measure intracellular mean fluorescence intensity (MFI) of daunorubicin (DNR). P-gp expression was determined by immunohistochemistry. RT-PCR technique was used to examine the mdr1 mRNA level.</p><p><b>RESULTS</b>IC(50) of ADM in K562/A02 cells was decreased when treated with Cur or EM, and the reversal times (RvT) was 4.9, 3.7 respectively. The RvT reached to 11.3 when treated with Cur (2.5 microg/ml) combined with EM (120 microg/ml). The DNR MFI in K562/A02 cells was significantly lower than that in K562 cells (P < 0.01), and was increased significantly when treated with Cur (2.5 microg/ml) or EM (120 microg/ml) (P < 0.05). There was no significant difference between DNR MFI of K562/A02 cells treated with Cur (2.5 microg/ml) or EM (120 microg/ml). Immunohistochemistry showed that P-gp expression was significantly higher in K562/A02 cells than in K562 cells (P < 0.01), and was reduced in K562/A02 cells treated with each (P < 0.01), though being still higher than that in K562 cells (P < 0.01). P-gp expression of K562/A02 cells treated with each drug for 5 days were lower than that for 3 days (P < 0.01), and lowered further when treated with Cur and EM together (P < 0.01). Mdr1 mRNA level in K562/A02 cells was higher than in K562 cells (P < 0.01), and was decreased when treated with each of the drugs (P < 0.01). The mdr1 mRNA level of K562/A02 cells treated with Cur (2.5 microg/ml) plus EM (120 microg/ml) was decreased most significantly than that treated with other group of drugs. After 5 day treatment the mdr1 mRNA level of K562/A02 cells with Cur (2.5 microg/ml) was lower than that with EM 120 microg/ml (P < 0.01).</p><p><b>CONCLUSIONS</b>Either Cur or EM can partly reverse the multidrug resistance of K562/A02 cells and decrease the expression and function of P-gp in a time-dependent way. MDR reversing effect of Cur combined with EM is stronger than that of Cur or EM alone.</p>
Assuntos
Humanos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Genética , Metabolismo , Antineoplásicos , Farmacologia , Proliferação de Células , Sobrevivência Celular , Curcumina , Farmacologia , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Epirubicina , Farmacologia , Eritromicina , Farmacologia , Regulação Neoplásica da Expressão Gênica , Imuno-Histoquímica , Células K562 , Leucemia Eritroblástica Aguda , Genética , Metabolismo , Patologia , RNA Mensageiro , Genética , Metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de TempoRESUMO
<p><b>OBJECTIVE</b>Human Parvovirus B19 (HPV B19) is a small (23 nm), non-enveloped DNA virus found in 1974. It has been proved that HPV B19 is associated with a variety of childhood diseases, such as erythema infectious, transient aplastic crisis, aplastic anemia, idiopathic thrombocytopenic purpura and arthropathy, etc. There have been no any effective vaccines to prevent HPV B19 infection so far. The HPV B19 genome is composed of 5.6 kb single strand DNA. This genome encodes a nonstructural protein NS1, two structural proteins VP1 and VP2. Most neutralizing linear epitopes of HPV B19 cluster in the VP1 unique and VP1-VP2 junction regions. Only proteins encoded by genes of the VP1 unique and VP1-VP2 junction regions can stimulate bodies to produce protective antibodies. Aim of the present study was to get the VP1 unique region gene of HPV B19 and to analyze the genetic diversity so as to further study its function and application.</p><p><b>METHODS</b>The VP1 unique region gene of HPV B19 was amplified from the serum of a child with idiopathic thrombocytopenic purpura by PCR. The purified PCR product was cloned into pGEM-T easy vector and transfected into the host strain E. coli (DH5 alpha). Positive clones were chosen and then the target gene was sequenced.</p><p><b>RESULTS</b>The target gene sequence of HPV B19 VP1 unique region was amplified and cloned successfully. It had 705 nucleotides. Compared with the relevant sequences published in Genbank, the sequencing results were revealed with two nucleotides changes in the HPV B19 VP1 unique region, but their coding amino acid were not changed.</p><p><b>CONCLUSION</b>It is suggested that genetic diversity exists in the VP1 unique region of HPV B19. Construction of the recombinant plasmid of HPV B19 VP1 unique region gene might benefit to further study.</p>