Limits...
A new mixed-backbone oligonucleotide against glucosylceramide synthase sensitizes multidrug-resistant tumors to apoptosis.

Patwardhan GA, Zhang QJ, Yin D, Gupta V, Bao J, Senkal CE, Ogretmen B, Cabot MC, Shah GV, Sylvester PW, Jazwinski SM, Liu YY - PLoS ONE (2009)

Bottom Line: The sensitization effects of MBO-asGCS relied on the decreases of gene expression and enzyme activity of GCS, and on the increases of C(18)-ceramide and of caspase-executed apoptosis.MBO-asGCS was accumulation in tumor xenografts was greater in other tissues, excepting liver and kidneys; but MBO-asGCS did not exert significant toxic effects on liver and kidneys.This study, for the first time in vivo, has demonstrated that GCS is a promising therapeutic target for cancer drug resistance, and MBO-asGCS has the potential to be developed as an antineoplastic agent.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Pharmaceutical Sciences, University of Louisiana at Monroe, Monroe, Louisiana, United States of America.

ABSTRACT
Enhanced ceramide glycosylation catalyzed by glucosylceramide synthase (GCS) limits therapeutic efficiencies of antineoplastic agents including doxorubicin in drug-resistant cancer cells. Aimed to determine the role of GCS in tumor response to chemotherapy, a new mixed-backbone oligonucleotide (MBO-asGCS) with higher stability and efficiency has been generated to silence human GCS gene. MBO-asGCS was taken up efficiently in both drug-sensitive and drug-resistant cells, but it selectively suppressed GCS overexpression, and sensitized drug-resistant cells. MBO-asGCS increased doxorubicin sensitivity by 83-fold in human NCI/ADR-RES, and 43-fold in murine EMT6/AR1 breast cancer cells, respectively. In tumor-bearing mice, MBO-asGCS treatment dramatically inhibited the growth of multidrug-resistant NCI/ADR-RE tumors, decreasing tumor volume to 37%, as compared with scrambled control. Furthermore, MBO-asGCS sensitized multidrug-resistant tumors to chemotherapy, increasing doxorubicin efficiency greater than 2-fold. The sensitization effects of MBO-asGCS relied on the decreases of gene expression and enzyme activity of GCS, and on the increases of C(18)-ceramide and of caspase-executed apoptosis. MBO-asGCS was accumulation in tumor xenografts was greater in other tissues, excepting liver and kidneys; but MBO-asGCS did not exert significant toxic effects on liver and kidneys. This study, for the first time in vivo, has demonstrated that GCS is a promising therapeutic target for cancer drug resistance, and MBO-asGCS has the potential to be developed as an antineoplastic agent.

Show MeSH

Related in: MedlinePlus

MBO-asGCS increases doxorubicin sensitivity in drug-resistant cancer cells.Cells (4,000/well) were plated in 96-well plates and pretreated with MBO-asGCS (50 nM). After 24 hr growth, cells were shifted to 5% FBS medium containing increasing concentrations of agents and grown for additional 72 hr. Cell viability was measured using the CellTiter-Glo luminescent cell viability assay. a. Cell viability after C6-ceramide treatment. ADR-RE, NCI/ADR-RE cells; *, p<0.01 compared with vehicle treatment. b. EC50 values for C6-ceramide. *, p<0.001 compared with vehicle treatments. c. Cell viability after doxorubicin treatment. d. EC50 values for doxorubicin. *, p<0.001 compared with vehicle treatment.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2735002&req=5

pone-0006938-g003: MBO-asGCS increases doxorubicin sensitivity in drug-resistant cancer cells.Cells (4,000/well) were plated in 96-well plates and pretreated with MBO-asGCS (50 nM). After 24 hr growth, cells were shifted to 5% FBS medium containing increasing concentrations of agents and grown for additional 72 hr. Cell viability was measured using the CellTiter-Glo luminescent cell viability assay. a. Cell viability after C6-ceramide treatment. ADR-RE, NCI/ADR-RE cells; *, p<0.01 compared with vehicle treatment. b. EC50 values for C6-ceramide. *, p<0.001 compared with vehicle treatments. c. Cell viability after doxorubicin treatment. d. EC50 values for doxorubicin. *, p<0.001 compared with vehicle treatment.

Mentions: Additional studies showed that MBO-asGCS significantly increased cytotoxicity of ceramide and doxorubicin in drug-resistant cells, but not in drug-sensitive cells. MBO-asGCS pretreatment (50 nM) did not increase ceramide cytotoxicity in drug-sensitive MCF-7 and EMT6 cells. In contrast, MBO-asGCS (50 nM) significantly increased ceramide cytotoxicity in drug-resistant NCI/ADR-RE and EMT6/AR1; the EC50 values for C6-ceramide decreased to approximately 50% in both resistant cell lines (Fig. 3a, 3b). MBO-asGCS pretreatment markedly increased doxorubicin sensitivity in drug-resistant cells; the EC50 values for doxorubicin decreased by 83-fold (0.18 vs. 12.5 µM) in NCI/ADR-RE, and by 43-fold (0.20 vs. 8.6 µM) in EMT6/AR1, respectively (Fig. 3c and 3d). By comparison, MBO-asGCS only mildly (by 50%) decreased the EC50 values for doxorubicin in sensitive counterparts of MCF-7 and EMT6 cells. These results demonstrate that suppressing GCS overexpression sensitizes resistant cancer cells to therapeutic agents, such as doxorubicin whose therapeutic efficiency is associated with ceramide actuation [11], [41], [42].


A new mixed-backbone oligonucleotide against glucosylceramide synthase sensitizes multidrug-resistant tumors to apoptosis.

Patwardhan GA, Zhang QJ, Yin D, Gupta V, Bao J, Senkal CE, Ogretmen B, Cabot MC, Shah GV, Sylvester PW, Jazwinski SM, Liu YY - PLoS ONE (2009)

MBO-asGCS increases doxorubicin sensitivity in drug-resistant cancer cells.Cells (4,000/well) were plated in 96-well plates and pretreated with MBO-asGCS (50 nM). After 24 hr growth, cells were shifted to 5% FBS medium containing increasing concentrations of agents and grown for additional 72 hr. Cell viability was measured using the CellTiter-Glo luminescent cell viability assay. a. Cell viability after C6-ceramide treatment. ADR-RE, NCI/ADR-RE cells; *, p<0.01 compared with vehicle treatment. b. EC50 values for C6-ceramide. *, p<0.001 compared with vehicle treatments. c. Cell viability after doxorubicin treatment. d. EC50 values for doxorubicin. *, p<0.001 compared with vehicle treatment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2735002&req=5

pone-0006938-g003: MBO-asGCS increases doxorubicin sensitivity in drug-resistant cancer cells.Cells (4,000/well) were plated in 96-well plates and pretreated with MBO-asGCS (50 nM). After 24 hr growth, cells were shifted to 5% FBS medium containing increasing concentrations of agents and grown for additional 72 hr. Cell viability was measured using the CellTiter-Glo luminescent cell viability assay. a. Cell viability after C6-ceramide treatment. ADR-RE, NCI/ADR-RE cells; *, p<0.01 compared with vehicle treatment. b. EC50 values for C6-ceramide. *, p<0.001 compared with vehicle treatments. c. Cell viability after doxorubicin treatment. d. EC50 values for doxorubicin. *, p<0.001 compared with vehicle treatment.
Mentions: Additional studies showed that MBO-asGCS significantly increased cytotoxicity of ceramide and doxorubicin in drug-resistant cells, but not in drug-sensitive cells. MBO-asGCS pretreatment (50 nM) did not increase ceramide cytotoxicity in drug-sensitive MCF-7 and EMT6 cells. In contrast, MBO-asGCS (50 nM) significantly increased ceramide cytotoxicity in drug-resistant NCI/ADR-RE and EMT6/AR1; the EC50 values for C6-ceramide decreased to approximately 50% in both resistant cell lines (Fig. 3a, 3b). MBO-asGCS pretreatment markedly increased doxorubicin sensitivity in drug-resistant cells; the EC50 values for doxorubicin decreased by 83-fold (0.18 vs. 12.5 µM) in NCI/ADR-RE, and by 43-fold (0.20 vs. 8.6 µM) in EMT6/AR1, respectively (Fig. 3c and 3d). By comparison, MBO-asGCS only mildly (by 50%) decreased the EC50 values for doxorubicin in sensitive counterparts of MCF-7 and EMT6 cells. These results demonstrate that suppressing GCS overexpression sensitizes resistant cancer cells to therapeutic agents, such as doxorubicin whose therapeutic efficiency is associated with ceramide actuation [11], [41], [42].

Bottom Line: The sensitization effects of MBO-asGCS relied on the decreases of gene expression and enzyme activity of GCS, and on the increases of C(18)-ceramide and of caspase-executed apoptosis.MBO-asGCS was accumulation in tumor xenografts was greater in other tissues, excepting liver and kidneys; but MBO-asGCS did not exert significant toxic effects on liver and kidneys.This study, for the first time in vivo, has demonstrated that GCS is a promising therapeutic target for cancer drug resistance, and MBO-asGCS has the potential to be developed as an antineoplastic agent.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Pharmaceutical Sciences, University of Louisiana at Monroe, Monroe, Louisiana, United States of America.

ABSTRACT
Enhanced ceramide glycosylation catalyzed by glucosylceramide synthase (GCS) limits therapeutic efficiencies of antineoplastic agents including doxorubicin in drug-resistant cancer cells. Aimed to determine the role of GCS in tumor response to chemotherapy, a new mixed-backbone oligonucleotide (MBO-asGCS) with higher stability and efficiency has been generated to silence human GCS gene. MBO-asGCS was taken up efficiently in both drug-sensitive and drug-resistant cells, but it selectively suppressed GCS overexpression, and sensitized drug-resistant cells. MBO-asGCS increased doxorubicin sensitivity by 83-fold in human NCI/ADR-RES, and 43-fold in murine EMT6/AR1 breast cancer cells, respectively. In tumor-bearing mice, MBO-asGCS treatment dramatically inhibited the growth of multidrug-resistant NCI/ADR-RE tumors, decreasing tumor volume to 37%, as compared with scrambled control. Furthermore, MBO-asGCS sensitized multidrug-resistant tumors to chemotherapy, increasing doxorubicin efficiency greater than 2-fold. The sensitization effects of MBO-asGCS relied on the decreases of gene expression and enzyme activity of GCS, and on the increases of C(18)-ceramide and of caspase-executed apoptosis. MBO-asGCS was accumulation in tumor xenografts was greater in other tissues, excepting liver and kidneys; but MBO-asGCS did not exert significant toxic effects on liver and kidneys. This study, for the first time in vivo, has demonstrated that GCS is a promising therapeutic target for cancer drug resistance, and MBO-asGCS has the potential to be developed as an antineoplastic agent.

Show MeSH
Related in: MedlinePlus