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Sensitization of chemo-resistant human chronic myeloid leukemia stem-like cells to Hsp90 inhibitor by SIRT1 inhibition.

Kim HB, Lee SH, Um JH, Kim MJ, Hyun SK, Gong EJ, Oh WK, Kang CD, Kim SH - Int. J. Biol. Sci. (2015)

Bottom Line: The current investigation was undertaken to examine the effectiveness of the combination treatment of Hsp90 inhibitor and SIRT1 inhibitor in inhibiting the growth of chemo-resistant stem-like cells isolated from human chronic myeloid leukemia K562 cells.Inhibition of SIRT1 by use of SIRT1 siRNA or SIRT1 inhibitors (amurensin G and EX527) effectively potentiated sensitivity of Hsp90 inhibitors (17-AAG and AUY922) in CD44(high) K562 stem-like cells expressing high levels of CSC-related molecules including Oct4, CD34, β-catenin, c-Myc, mutant p53 (mut p53), BCRP and P-glycoprotein (P-gp) as well as CD44.Our data suggest that combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be an effective therapeutic approach to target CSCs that are resistant to current therapies.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Biochemistry, Pusan National University School of Medicine, Yangsan 626-870, Korea.

ABSTRACT
Development of effective therapeutic strategies to eliminate cancer stem-like cells (CSCs), which play a major role in drug resistance and disease recurrence, is critical to improve cancer treatment outcomes. The current investigation was undertaken to examine the effectiveness of the combination treatment of Hsp90 inhibitor and SIRT1 inhibitor in inhibiting the growth of chemo-resistant stem-like cells isolated from human chronic myeloid leukemia K562 cells. Inhibition of SIRT1 by use of SIRT1 siRNA or SIRT1 inhibitors (amurensin G and EX527) effectively potentiated sensitivity of Hsp90 inhibitors (17-AAG and AUY922) in CD44(high) K562 stem-like cells expressing high levels of CSC-related molecules including Oct4, CD34, β-catenin, c-Myc, mutant p53 (mut p53), BCRP and P-glycoprotein (P-gp) as well as CD44. SIRT1 depletion caused significant down-regulation of heat shock factor 1 (HSF1)/heat shock proteins (Hsps) as well as these CSC-related molecules, which led to the sensitization of CD44(high) K562 cells to Hsp90 inhibitor by SIRT1 inhibitor. Moreover, 17-AAG-mediated activation of HSF1/Hsps and P-gp-mediated efflux, major causes of Hsp90 inhibitor resistance, was suppressed by SIRT1 inhibitor in K562-CD44(high) cells. Our data suggest that combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be an effective therapeutic approach to target CSCs that are resistant to current therapies.

No MeSH data available.


Related in: MedlinePlus

Effect of SIRT1 inhibitors on P-gp (or BCRP)-mediated efflux activity of Hsp90 inhibitors in CD44high K562 cells. Cell suspension isolated from the cells treated with 17-AAG (5 μM) or in the presence or absence of AG (5 μg/ml) or for 12 h. And then these are incubated with rhodamine 123 (A) or Hoechst 33342 (B) and further incubated at 37 °C for 4 h to allow P-gp (or BCRP) transporter-mediated efflux. Cellular fluorescence was analyzed immediately by using flow cytometer.
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Figure 5: Effect of SIRT1 inhibitors on P-gp (or BCRP)-mediated efflux activity of Hsp90 inhibitors in CD44high K562 cells. Cell suspension isolated from the cells treated with 17-AAG (5 μM) or in the presence or absence of AG (5 μg/ml) or for 12 h. And then these are incubated with rhodamine 123 (A) or Hoechst 33342 (B) and further incubated at 37 °C for 4 h to allow P-gp (or BCRP) transporter-mediated efflux. Cellular fluorescence was analyzed immediately by using flow cytometer.

Mentions: Since hyaluronan receptor CD44 forms complexes with multidrug transporters, BCRP and P-gp in the plasma membrane, and disassembly of CD44-transporter complexes with hyaluronan oligomers induces internalization of CD44, BCRP, and P-gp, and consequently, suppresses drug transporter activity and increases sensitivity to anticancer drug 36, we examined whether SIRT1 inhibition blocks multidrug transporters-mediated efflux activity in CD44high K562 cells, using a flow cytometric functional efflux assay based on the extrusion of rhodamine 123 (Rho 123), a fluorescent substrate of P-gp (Fig. 5A) and Hoechst 33342, a fluorescent substrate of BCRP (Fig. 5B). When CD44high K562 cells treated with 17-AAG, Rho123 efflux was rather increased, possibly due to induction of P-gp, but amurensin G significantly suppressed efflux of Rho 123. Moreover, combined treatment of amurensin G and 17-AAG suppressed remarkably the efflux of Rho 123 in CD44high K562 cells, which was consistent with the down-regulation of P-gp in CD44high K562 cells after combined treatment with 17-AAG and SIRT1 siRNA (Fig. 4). Since BCRP may also function to decrease cellular accumulation of 17-AAG in CD44high K562 cells, we examined the effect of amurensin G on BCRP-mediated efflux using Hoechst 33342 (Fig. 5B). When CD44high K562 cells treated with 17-AAG, Hoechst 33342 efflux was increased like Rho 123 efflux, possibly due to induction of BCRP, but amurensin G significantly suppressed efflux of Hoechst 33342. Moreover, combined treatment of amurensin G and 17-AAG suppressed remarkably the efflux of Hoechst 33342 in CD44high K562 cells, which was consistent with the down-regulation of BCRP in CD44high K562 cells after combined treatment with 17-AAG and amurensin G (Fig. 4). These results suggest that SIRT1 inhibitor is highly effective to increase an efficacy of Hsp90 inhibitors possibly through down-regulation of P-gp/BCRP.


Sensitization of chemo-resistant human chronic myeloid leukemia stem-like cells to Hsp90 inhibitor by SIRT1 inhibition.

Kim HB, Lee SH, Um JH, Kim MJ, Hyun SK, Gong EJ, Oh WK, Kang CD, Kim SH - Int. J. Biol. Sci. (2015)

Effect of SIRT1 inhibitors on P-gp (or BCRP)-mediated efflux activity of Hsp90 inhibitors in CD44high K562 cells. Cell suspension isolated from the cells treated with 17-AAG (5 μM) or in the presence or absence of AG (5 μg/ml) or for 12 h. And then these are incubated with rhodamine 123 (A) or Hoechst 33342 (B) and further incubated at 37 °C for 4 h to allow P-gp (or BCRP) transporter-mediated efflux. Cellular fluorescence was analyzed immediately by using flow cytometer.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495410&req=5

Figure 5: Effect of SIRT1 inhibitors on P-gp (or BCRP)-mediated efflux activity of Hsp90 inhibitors in CD44high K562 cells. Cell suspension isolated from the cells treated with 17-AAG (5 μM) or in the presence or absence of AG (5 μg/ml) or for 12 h. And then these are incubated with rhodamine 123 (A) or Hoechst 33342 (B) and further incubated at 37 °C for 4 h to allow P-gp (or BCRP) transporter-mediated efflux. Cellular fluorescence was analyzed immediately by using flow cytometer.
Mentions: Since hyaluronan receptor CD44 forms complexes with multidrug transporters, BCRP and P-gp in the plasma membrane, and disassembly of CD44-transporter complexes with hyaluronan oligomers induces internalization of CD44, BCRP, and P-gp, and consequently, suppresses drug transporter activity and increases sensitivity to anticancer drug 36, we examined whether SIRT1 inhibition blocks multidrug transporters-mediated efflux activity in CD44high K562 cells, using a flow cytometric functional efflux assay based on the extrusion of rhodamine 123 (Rho 123), a fluorescent substrate of P-gp (Fig. 5A) and Hoechst 33342, a fluorescent substrate of BCRP (Fig. 5B). When CD44high K562 cells treated with 17-AAG, Rho123 efflux was rather increased, possibly due to induction of P-gp, but amurensin G significantly suppressed efflux of Rho 123. Moreover, combined treatment of amurensin G and 17-AAG suppressed remarkably the efflux of Rho 123 in CD44high K562 cells, which was consistent with the down-regulation of P-gp in CD44high K562 cells after combined treatment with 17-AAG and SIRT1 siRNA (Fig. 4). Since BCRP may also function to decrease cellular accumulation of 17-AAG in CD44high K562 cells, we examined the effect of amurensin G on BCRP-mediated efflux using Hoechst 33342 (Fig. 5B). When CD44high K562 cells treated with 17-AAG, Hoechst 33342 efflux was increased like Rho 123 efflux, possibly due to induction of BCRP, but amurensin G significantly suppressed efflux of Hoechst 33342. Moreover, combined treatment of amurensin G and 17-AAG suppressed remarkably the efflux of Hoechst 33342 in CD44high K562 cells, which was consistent with the down-regulation of BCRP in CD44high K562 cells after combined treatment with 17-AAG and amurensin G (Fig. 4). These results suggest that SIRT1 inhibitor is highly effective to increase an efficacy of Hsp90 inhibitors possibly through down-regulation of P-gp/BCRP.

Bottom Line: The current investigation was undertaken to examine the effectiveness of the combination treatment of Hsp90 inhibitor and SIRT1 inhibitor in inhibiting the growth of chemo-resistant stem-like cells isolated from human chronic myeloid leukemia K562 cells.Inhibition of SIRT1 by use of SIRT1 siRNA or SIRT1 inhibitors (amurensin G and EX527) effectively potentiated sensitivity of Hsp90 inhibitors (17-AAG and AUY922) in CD44(high) K562 stem-like cells expressing high levels of CSC-related molecules including Oct4, CD34, β-catenin, c-Myc, mutant p53 (mut p53), BCRP and P-glycoprotein (P-gp) as well as CD44.Our data suggest that combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be an effective therapeutic approach to target CSCs that are resistant to current therapies.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Biochemistry, Pusan National University School of Medicine, Yangsan 626-870, Korea.

ABSTRACT
Development of effective therapeutic strategies to eliminate cancer stem-like cells (CSCs), which play a major role in drug resistance and disease recurrence, is critical to improve cancer treatment outcomes. The current investigation was undertaken to examine the effectiveness of the combination treatment of Hsp90 inhibitor and SIRT1 inhibitor in inhibiting the growth of chemo-resistant stem-like cells isolated from human chronic myeloid leukemia K562 cells. Inhibition of SIRT1 by use of SIRT1 siRNA or SIRT1 inhibitors (amurensin G and EX527) effectively potentiated sensitivity of Hsp90 inhibitors (17-AAG and AUY922) in CD44(high) K562 stem-like cells expressing high levels of CSC-related molecules including Oct4, CD34, β-catenin, c-Myc, mutant p53 (mut p53), BCRP and P-glycoprotein (P-gp) as well as CD44. SIRT1 depletion caused significant down-regulation of heat shock factor 1 (HSF1)/heat shock proteins (Hsps) as well as these CSC-related molecules, which led to the sensitization of CD44(high) K562 cells to Hsp90 inhibitor by SIRT1 inhibitor. Moreover, 17-AAG-mediated activation of HSF1/Hsps and P-gp-mediated efflux, major causes of Hsp90 inhibitor resistance, was suppressed by SIRT1 inhibitor in K562-CD44(high) cells. Our data suggest that combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be an effective therapeutic approach to target CSCs that are resistant to current therapies.

No MeSH data available.


Related in: MedlinePlus