Search results

Search:
in the keywords: shRNA

Sort By:

Limit search:

Reversal of drug resistance by silencing Survivin gene expression in acute myeloid leukemia cells

100%

Wu Y.-H., You Y., Chen Z.-C., Zou P.

2008

vol. 55

issue 4

673-680

The role of Survivin in the pathogenesis of leukemia was explored in order to discover the effective avenues for gene therapy. Most primary leukemia cells isolated from patients as well as three leukemia cell lines (HL-60, K562, and U937) all expressed Survivin gene. To investigate the relationship between Survivin and chemotherapeutic resistance, HL-60 cells were treated with daunorubicin (DNR), mitoxantrone (MIT) or arsenious oxide (As2O3), and it was found that after 24 h the level of Survivin mRNA was decreased by 9.7%, 41.0% and 27.5%, respectively. At 72 h, the level of Survivin mRNA was increased by 21.2% and 65.2% in HL-60 cells treated with DNR or MIT, but decreased by 33.2% in those treated with As2O3 as compared with that in the cells treated for 24 h. These results showed that DNR and MIT could initally decrease the expression of Survivin and then increase it, but As2O3 could decrease the Survivin expression continually. Furthermore, shRNA plasmids targeting the Survivin gene (pEGFP-Survivin), which can silence the expression of Survivin with a high specificity, were constructed. pEGFP-Survivin and pEGFP-H1 were transfected into HL-60 cells via electroporation and selected by G418, and HL-60/Survivin and HL-60/EGFP cells were obtained. After treatment with DNR, the cell survival rate and IC50 of DNR in HL-60/Survivin cells were decreased substantially as compared with those of HL-60/EGFP and HL-60 cells (IC50 of DNR: 18.3 ± 2.45 vs 40.8 ± 6.37 and 39.2 ± 5.91 ng/ml, respectively), and the apoptosis rate was elevated ((84.3 ± 19.7)% vs (45.8 ± 13.8)% and (50.9 ± 12.4)%, respectively). These results suggest that shRNA can down-regulate the expression of Survivin in HL-60 cells substantially and improve their sensitivity to DNR. They also further explain the pathogenesis of leukemia drug resistance and provide new theory in the design of clinical therapies.

Pharmacological versus genetic inhibition of heme oxygenase-1 - the comparison of metalloporphyrins, shRNA and CRISPR/Cas9 system

86%

Mucha O., Podkalicka P., Czarnek M., Biela A., Mieczkowski M., Kachamakova-Trojanowska N., Stepniewski J., Jozkowicz A., Dulak J., Loboda A.

2018

vol. 65

issue 2

277-286

Inhibition of heme oxygenase-1 (HO-1, encoded by HMOX1), a cytoprotective, anti-apoptotic and anti-inflammatory enzyme, may serve as a valuable therapy in various pathophysiological processes, including tumorigenesis. We compared the effect of chemical inhibitors - metalloporphyrins, with genetic tools - shRNA and CRISPR/Cas9 systems, to knock-down (KD)/knock-out (KO) HO-1 expression/activity. 293T cells were incubated with metalloporphyrins, tin and zinc protoporphyrins (SnPPIX and ZnPPIX, respectively) or were either transduced with lentiviral vectors encoding different shRNA sequences against HO-1 or were modified by CRISPR/Cas9 system targeting HMOX1. Metalloporphyrins decreased HO activity but concomitantly strongly induced HO-1 mRNA and protein in 293T cells. On the other hand, only slight basal HO-1 inhibition in shRNA KD 293T cell lines was confirmed on mRNA and protein level with no significant effect on enzyme activity. Nevertheless, silencing effect was much stronger when CRISPR/Cas9-mediated knock-out was performed. Most of the clones harboring mutations within HMOX1 locus did not express HO-1 protein and failed to increase bilirubin concentration after hemin stimulation. Furthermore, CRISPR/Cas9-mediated HO-1 depletion decreased 293T viability, growth, clonogenic potential and increased sensitivity to H2O2 treatment. In summary, we have shown that not all technologies can be used for inhibition of HO activity in vitro with the same efficiency. In our hands, the most potent and comprehensible results can be obtained using genetic tools, especially CRISPR/Cas9 approach.

Refine search results

2 Acta Biochimica Polonica

1 2018

1 2008

1 Biela A.

1 Chen Z.-C.

1 Czarnek M.

1 Dulak J.

1 Jozkowicz A.

1 Kachamakova-Trojanowska N.

1 Loboda A.

1 Mieczkowski M.

1 Mucha O.

1 Podkalicka P.

1 Stepniewski J.

1 Wu Y.-H.

1 You Y.

1 Zou P.

Search results

Reversal of drug resistance by silencing Survivin gene expression in acute myeloid leukemia cells

Pharmacological versus genetic inhibition of heme oxygenase-1 - the comparison of metalloporphyrins, shRNA and CRISPR/Cas9 system