Limits...
Pyrvinium targets the unfolded protein response to hypoglycemia and its anti-tumor activity is enhanced by combination therapy.

Yu DH, Macdonald J, Liu G, Lee AS, Ly M, Davis T, Ke N, Zhou D, Wong-Staal F, Li QX - PLoS ONE (2008)

Bottom Line: Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187.Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium.However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

View Article: PubMed Central - PubMed

Affiliation: iTherX Pharmaceuticals, Inc., San Diego, California, United States of America. yu@itherx.com

ABSTRACT
We identified pyrvinium pamoate, an old anthelminthic medicine, which preferentially inhibits anchorage-independent growth of cancer cells over anchorage-dependent growth (approximately 10 fold). It was also reported by others to have anti-tumor activity in vivo and selective toxicity against cancer cells under glucose starvation in vitro, but with unknown mechanism. Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187. Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium. Constitutive expression of GRP78 via transgene partially protected cells from pyrvinium induced cell death under glucose starvation, suggesting that suppression of the UPR is involved in pyrvinium mediated cytotoxicity under glucose starvation. Xenograft experiments showed rather marginal overall anti-tumor activity for pyrvinium as a monotherapy. However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

Show MeSH

Related in: MedlinePlus

Over-expression of GRP78 protects cells from pyrvinium-induced cell death.A: Quantitative real-time RT-PCR analysis. CHO and C.1 cells cultured in growth media with or without 2DG were treated with pyrvinium phosphate (pyrvinium-p) for 6 hrs. Total RNA was harvested and subjected to Taqman real-time PCR analysis for GRP78. B and C: Clonogenicity assay. CHO and C.1 cells were seeded on day 1. The cultures were treated on day 3 with 2DG (10 mM), pyrvinium-p (0.1 µM) or combination of 2DG and pyrvinium-p for another 18 hrs and continued to culture for 2 weeks. The colonies were quantitated. D: alamarBlue readout of cell proliferation (3 days in 96 well plates) as described in figure 1. The SD of triplicate samples is shown.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2597738&req=5

pone-0003951-g004: Over-expression of GRP78 protects cells from pyrvinium-induced cell death.A: Quantitative real-time RT-PCR analysis. CHO and C.1 cells cultured in growth media with or without 2DG were treated with pyrvinium phosphate (pyrvinium-p) for 6 hrs. Total RNA was harvested and subjected to Taqman real-time PCR analysis for GRP78. B and C: Clonogenicity assay. CHO and C.1 cells were seeded on day 1. The cultures were treated on day 3 with 2DG (10 mM), pyrvinium-p (0.1 µM) or combination of 2DG and pyrvinium-p for another 18 hrs and continued to culture for 2 weeks. The colonies were quantitated. D: alamarBlue readout of cell proliferation (3 days in 96 well plates) as described in figure 1. The SD of triplicate samples is shown.

Mentions: GRP78 and GRP94 are two ER resident stress response chaperones that are transcriptionally induced during glucose deprivation as part of the UPR, which protects cells from apoptosis under a variety of stress conditions [5], [24]. We were therefore interested in whether pyrvinium affects GRP78 and GRP94 induction caused by glucose deprivation. Figures 3A and 3B shows the induction of GRP78 and GRP94 mRNA levels in Panc-1 cells, as measured by Taqman real-time RT-PCR for 6 hours (3 and 2 fold respectively) and 24 hours (11 and 5 fold respectively) of glucose starvation. Interestingly, these inductions were completely suppressed by pyrvinium treatments at 0.1 and 0.3 µM (Figure 3A and 3B), the concentrations causing cytotoxicity. Since there was no apparent cell death measured by alamarBlue assay for the 6 hour treatment, the observed suppression of the GRP78 and GRP94 induction did not result from cell death. Consistently, similar an inhibitory effect was also reflected at protein levels as shown by immunoblot analysis (Figure 3C). Importantly, this suppression was also seen in all the tested cells including PC3 human prostate cancer, 143b osterosarcoma cell lines (Figure 3D) and CHO cells (Figure 4), suggesting an ubiquitous effect of pyrvinium on the UPR


Pyrvinium targets the unfolded protein response to hypoglycemia and its anti-tumor activity is enhanced by combination therapy.

Yu DH, Macdonald J, Liu G, Lee AS, Ly M, Davis T, Ke N, Zhou D, Wong-Staal F, Li QX - PLoS ONE (2008)

Over-expression of GRP78 protects cells from pyrvinium-induced cell death.A: Quantitative real-time RT-PCR analysis. CHO and C.1 cells cultured in growth media with or without 2DG were treated with pyrvinium phosphate (pyrvinium-p) for 6 hrs. Total RNA was harvested and subjected to Taqman real-time PCR analysis for GRP78. B and C: Clonogenicity assay. CHO and C.1 cells were seeded on day 1. The cultures were treated on day 3 with 2DG (10 mM), pyrvinium-p (0.1 µM) or combination of 2DG and pyrvinium-p for another 18 hrs and continued to culture for 2 weeks. The colonies were quantitated. D: alamarBlue readout of cell proliferation (3 days in 96 well plates) as described in figure 1. The SD of triplicate samples is shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2597738&req=5

pone-0003951-g004: Over-expression of GRP78 protects cells from pyrvinium-induced cell death.A: Quantitative real-time RT-PCR analysis. CHO and C.1 cells cultured in growth media with or without 2DG were treated with pyrvinium phosphate (pyrvinium-p) for 6 hrs. Total RNA was harvested and subjected to Taqman real-time PCR analysis for GRP78. B and C: Clonogenicity assay. CHO and C.1 cells were seeded on day 1. The cultures were treated on day 3 with 2DG (10 mM), pyrvinium-p (0.1 µM) or combination of 2DG and pyrvinium-p for another 18 hrs and continued to culture for 2 weeks. The colonies were quantitated. D: alamarBlue readout of cell proliferation (3 days in 96 well plates) as described in figure 1. The SD of triplicate samples is shown.
Mentions: GRP78 and GRP94 are two ER resident stress response chaperones that are transcriptionally induced during glucose deprivation as part of the UPR, which protects cells from apoptosis under a variety of stress conditions [5], [24]. We were therefore interested in whether pyrvinium affects GRP78 and GRP94 induction caused by glucose deprivation. Figures 3A and 3B shows the induction of GRP78 and GRP94 mRNA levels in Panc-1 cells, as measured by Taqman real-time RT-PCR for 6 hours (3 and 2 fold respectively) and 24 hours (11 and 5 fold respectively) of glucose starvation. Interestingly, these inductions were completely suppressed by pyrvinium treatments at 0.1 and 0.3 µM (Figure 3A and 3B), the concentrations causing cytotoxicity. Since there was no apparent cell death measured by alamarBlue assay for the 6 hour treatment, the observed suppression of the GRP78 and GRP94 induction did not result from cell death. Consistently, similar an inhibitory effect was also reflected at protein levels as shown by immunoblot analysis (Figure 3C). Importantly, this suppression was also seen in all the tested cells including PC3 human prostate cancer, 143b osterosarcoma cell lines (Figure 3D) and CHO cells (Figure 4), suggesting an ubiquitous effect of pyrvinium on the UPR

Bottom Line: Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187.Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium.However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

View Article: PubMed Central - PubMed

Affiliation: iTherX Pharmaceuticals, Inc., San Diego, California, United States of America. yu@itherx.com

ABSTRACT
We identified pyrvinium pamoate, an old anthelminthic medicine, which preferentially inhibits anchorage-independent growth of cancer cells over anchorage-dependent growth (approximately 10 fold). It was also reported by others to have anti-tumor activity in vivo and selective toxicity against cancer cells under glucose starvation in vitro, but with unknown mechanism. Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187. Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium. Constitutive expression of GRP78 via transgene partially protected cells from pyrvinium induced cell death under glucose starvation, suggesting that suppression of the UPR is involved in pyrvinium mediated cytotoxicity under glucose starvation. Xenograft experiments showed rather marginal overall anti-tumor activity for pyrvinium as a monotherapy. However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

Show MeSH
Related in: MedlinePlus