ABSTRACT
The acute myeloid leukemia is a very common malignant tumor of hematopoietic system, which is seriously harmful to human health. The long-term survival rate of routine chemotherapy is not satisfactory, especially in the high risk patients. Resistance to chemotherapy drugs is one of the major reasons, which causes the refractorines and relapse of the acute myeloid leukemia. The microRNA found in eukaryote is an endogenous non-coding micromolecular signle-stranded RNA of 19 to 25 nt. The miRNA can degrade the specific RNA or inhibit its translation through combining to 3' untranslated regions of the specific RNA, which contributes to regulate the expression of the target gene. There are already some evidences showing that the disorder of miRNA plays an important role in the genesis and progress of the tumors. Recently, more and more researches suggest that the miRNA is also important in the genesis of drug resistance to tumors. This review summarizes the research progress and the major mechanism of drug-resistance mediated by the miRNA in AML, including multiple drug resistance, cell cycle and the tolerance to apoptosis, all of which are associated with ABC transport protein.
ABSTRACT
<p><b>OBJECTIVE</b>To study the correlation between the excessive activation of Hedgehog signal and the drug resistance of multiple myeloma.</p><p><b>METHODS</b>The resistant cell line RPMI 8226/R of multiple myeloma was established by an ascending concentration gradient method. The experiment consisted of 4 groups: RPMI8226/R, RPMI8226/S, GANT61+RPMI8226/R and GANT61+RPMI8226/S. The CCK-8 (cell counting kit-8) assay was used to detect the cell proliferation inhibition rate in 4 groups; the RT-PCR was used to detect the expression of Gli1, Gli2, Shh, Ihh, Smo and Sufu in the RPMI8226/S and RPMI8226/R cells. The Western blot was used to detect the expression of the resistant protein Cyclin D1, P21 and BCL-2 and MDR-related signaling pathways protein p-Akt, p-MAPK and STAT3 in the RPMI8226/S and RPMI8226/R cells. After adding different concentration of GANT61, the Western blot was used to detect the expression of Gli2 in RPMI8226/R and RPMI8226/S cells.</p><p><b>RESULTS</b>The expression of Shh, Ihh, Smo Gli2 was enhanced significantly in the RPMI8226/R cells, but the expression of Sufu inhibitor was reduced, the expression level of related protein in Hedgehog signaling pathway was significanly higher in RPMI8226/R than that in RPMI8226/S. After theatment of GANT61 in vitro, the expression level of Gli2 in multiple myelom cells obviously decreased, the decreasing effect of GANT61 on Gli2 expression in RPMI8226/R cells was more significant than that in RPMI8226/S cells. The sensitivity of RPMI8226/R cells to DOX after treatment with GANT61 (IC) was risen from 7.11±0.061 µmol/L to 0.99±0.053 µmol/L, the corresponding cell resistance index decreased from 5.51 to 1.69.</p><p><b>CONCLUSION</b>the activation of Hedgehog signaling pathway is closely related with the resistance of multiple myeloma cells, and GANT61 can block the Hedgehog signaling pathway, thus Hedgehog signaling may be used as a new target for multiple myeloma treatment.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the diagnostic value of circulating serum miRNA for multiple myeloma.</p><p><b>METHODS</b>Forty blood samples from patients with multiple myeloma were collected from July 2013 to June 2014 in Department of Hematology, Zhongshan Hospital Affiliated to Xiamen University. The real-time quantitative PCR was performed to detect the serum expression levels of miRNAs (miR-29a, miR-155, miR-16 and miR-92a) circulating in the different stages of patients with multiple myeloma and evaluate the diagnostic value for patients with multiple myeloma.</p><p><b>RESULTS</b>The serum level of miR-29a significantly increased in newly diagnosed patients as compared to healthy donor (P<0.01), serum miR-155 levels were significantly lower as compared with healthy donor(P<0.001); The ratio of miR-29a and miR-155 was an effective biomarker for distinguishing multiple myeloma from healthy donor, their sensitivity and specificity were 80.8% and 83.3% respectively for myeloma diagnosis. the change of miR-29a expression was consistent with the changes of bone marrow plasma cells and M protein levels.</p><p><b>CONCLUSION</b>These circulating serum microRNA, such as miR-29a, miR-155 and miR-16, may serve as potential diagnostic biomarkers for multiple myeloma, and the ratio of miR-29a/miR-155 may serve as a most useful biomarker for myeloma diagnosis.</p>