PPAR? IS A NOVEL THERAPEUTIC TARGETS IN PH-POSITIVE LEUKEMIA CELLS
(Abstract release date: 05/19/16)
EHA Library. Okabe S. 06/09/16; 134704; PB1804
Dr. Seiichi Okabe
Contributions
Contributions
Abstract
Abstract: PB1804
Type: Publication Only
Background
ABL tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib and dasatinib have demonstrated the potency against Philadelphia chromosome (Ph)-positive leukemia patients. However, resistance to ABL TKI can develop in chronic myeloid leukemia (CML) patients due to BCR-ABL point mutations and leukemia stem cells, because ABL TKIs cannot eradicate leukemia stem cells. Therefore, new approach against BCR-ABL mutant cells and LSCs may improve the outcome of Ph-positive leukemia patients. Peroxisome proliferator-activated receptors (PPARs) compose a superfamily of nuclear hormone receptors and regulate the transcription of target genes. Three subtypes of PPARs (α, γ and δ/β) have been identified. PPARγ is expressed not only adipose tissue but also cancer cells. The PPARγ agonist, pioglitazone was used for the treatment of diabetes patients. Recently, it has been reported that PPARγ agonist eradicate leukemia stem cells of CML patients (Prost S et al. Nature. 2015;525 :380-3).
Aims
We hypothesized that targeting PPARγ, in combination with ABL TKI, would result in enhanced therapeutic activity in Ph-positive leukemia cells including T315I mutation and primary samples.
Methods
In this study, we investigated the effect of PPARγ agonist, pioglitazone on Ph-positive leukemia cell lines (K562, NCO2, Ba/F3 BCR-ABL, Ba/F3 T315I) and primary samples.
Results
72 h treatment of pioglitazone did not exhibit cell growth inhibition against K562 cells.We found that mRNA of PPAR subunit, PPARα and PPARγ was increased after pioglitazone treatment. We examined the intracellular signaling after treatment of pioglitazone. We found phosphorylation of BCR-ABL and Crk-L was not reduced after pioglitazone treatment. In contrast, phospohorylation of AMP-activated protein kinase (AMPK) was increased and S6 ribosomal protein was reduced. We investigated the pioglitazone activity against T315I positive cells. Pioglitazone did not induce cell growth inhibition of Ba/F3 T315I cells. However, combined treatment of Ba/F3 T315I cells with ponatinib and high concentration of pioglitazone caused more cytotoxicity than each drug alone. Phosphorylation of BCR-ABL and Crk-L was not reduced. However, phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We also found that the treatment of ponatinib and pioglitazone exhibits cell growth inhibition against Ph-positive primary samples with T315I mutation. Phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We next investigated the anti-angiogenic effects of PPARγ agonist on human umbilical vein endothelial cells (HUVEC). Pioglitazone inhibited tube formation of HUVEC (size, length and junction) in matrigel assay. Pioglitazone also inhibited chemotaxis of HUVEC.
Conclusion
Our study indicated that administration of the PPARγ agonist, pioglitazone enhances the effects of ABL TKI and is effective in suppression of angiogenesis, suggests that PPARγ agonist may possess promising clinical relevance as a candidate for treatment of Ph-positive leukemia patients.
Session topic: E-poster
Keyword(s): Acute lymphoblastic leukemia, Angiogenesis, Philadelphia chromosome
Type: Publication Only
Background
ABL tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib and dasatinib have demonstrated the potency against Philadelphia chromosome (Ph)-positive leukemia patients. However, resistance to ABL TKI can develop in chronic myeloid leukemia (CML) patients due to BCR-ABL point mutations and leukemia stem cells, because ABL TKIs cannot eradicate leukemia stem cells. Therefore, new approach against BCR-ABL mutant cells and LSCs may improve the outcome of Ph-positive leukemia patients. Peroxisome proliferator-activated receptors (PPARs) compose a superfamily of nuclear hormone receptors and regulate the transcription of target genes. Three subtypes of PPARs (α, γ and δ/β) have been identified. PPARγ is expressed not only adipose tissue but also cancer cells. The PPARγ agonist, pioglitazone was used for the treatment of diabetes patients. Recently, it has been reported that PPARγ agonist eradicate leukemia stem cells of CML patients (Prost S et al. Nature. 2015;525 :380-3).
Aims
We hypothesized that targeting PPARγ, in combination with ABL TKI, would result in enhanced therapeutic activity in Ph-positive leukemia cells including T315I mutation and primary samples.
Methods
In this study, we investigated the effect of PPARγ agonist, pioglitazone on Ph-positive leukemia cell lines (K562, NCO2, Ba/F3 BCR-ABL, Ba/F3 T315I) and primary samples.
Results
72 h treatment of pioglitazone did not exhibit cell growth inhibition against K562 cells.We found that mRNA of PPAR subunit, PPARα and PPARγ was increased after pioglitazone treatment. We examined the intracellular signaling after treatment of pioglitazone. We found phosphorylation of BCR-ABL and Crk-L was not reduced after pioglitazone treatment. In contrast, phospohorylation of AMP-activated protein kinase (AMPK) was increased and S6 ribosomal protein was reduced. We investigated the pioglitazone activity against T315I positive cells. Pioglitazone did not induce cell growth inhibition of Ba/F3 T315I cells. However, combined treatment of Ba/F3 T315I cells with ponatinib and high concentration of pioglitazone caused more cytotoxicity than each drug alone. Phosphorylation of BCR-ABL and Crk-L was not reduced. However, phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We also found that the treatment of ponatinib and pioglitazone exhibits cell growth inhibition against Ph-positive primary samples with T315I mutation. Phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We next investigated the anti-angiogenic effects of PPARγ agonist on human umbilical vein endothelial cells (HUVEC). Pioglitazone inhibited tube formation of HUVEC (size, length and junction) in matrigel assay. Pioglitazone also inhibited chemotaxis of HUVEC.
Conclusion
Our study indicated that administration of the PPARγ agonist, pioglitazone enhances the effects of ABL TKI and is effective in suppression of angiogenesis, suggests that PPARγ agonist may possess promising clinical relevance as a candidate for treatment of Ph-positive leukemia patients.
Session topic: E-poster
Keyword(s): Acute lymphoblastic leukemia, Angiogenesis, Philadelphia chromosome
Abstract: PB1804
Type: Publication Only
Background
ABL tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib and dasatinib have demonstrated the potency against Philadelphia chromosome (Ph)-positive leukemia patients. However, resistance to ABL TKI can develop in chronic myeloid leukemia (CML) patients due to BCR-ABL point mutations and leukemia stem cells, because ABL TKIs cannot eradicate leukemia stem cells. Therefore, new approach against BCR-ABL mutant cells and LSCs may improve the outcome of Ph-positive leukemia patients. Peroxisome proliferator-activated receptors (PPARs) compose a superfamily of nuclear hormone receptors and regulate the transcription of target genes. Three subtypes of PPARs (α, γ and δ/β) have been identified. PPARγ is expressed not only adipose tissue but also cancer cells. The PPARγ agonist, pioglitazone was used for the treatment of diabetes patients. Recently, it has been reported that PPARγ agonist eradicate leukemia stem cells of CML patients (Prost S et al. Nature. 2015;525 :380-3).
Aims
We hypothesized that targeting PPARγ, in combination with ABL TKI, would result in enhanced therapeutic activity in Ph-positive leukemia cells including T315I mutation and primary samples.
Methods
In this study, we investigated the effect of PPARγ agonist, pioglitazone on Ph-positive leukemia cell lines (K562, NCO2, Ba/F3 BCR-ABL, Ba/F3 T315I) and primary samples.
Results
72 h treatment of pioglitazone did not exhibit cell growth inhibition against K562 cells.We found that mRNA of PPAR subunit, PPARα and PPARγ was increased after pioglitazone treatment. We examined the intracellular signaling after treatment of pioglitazone. We found phosphorylation of BCR-ABL and Crk-L was not reduced after pioglitazone treatment. In contrast, phospohorylation of AMP-activated protein kinase (AMPK) was increased and S6 ribosomal protein was reduced. We investigated the pioglitazone activity against T315I positive cells. Pioglitazone did not induce cell growth inhibition of Ba/F3 T315I cells. However, combined treatment of Ba/F3 T315I cells with ponatinib and high concentration of pioglitazone caused more cytotoxicity than each drug alone. Phosphorylation of BCR-ABL and Crk-L was not reduced. However, phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We also found that the treatment of ponatinib and pioglitazone exhibits cell growth inhibition against Ph-positive primary samples with T315I mutation. Phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We next investigated the anti-angiogenic effects of PPARγ agonist on human umbilical vein endothelial cells (HUVEC). Pioglitazone inhibited tube formation of HUVEC (size, length and junction) in matrigel assay. Pioglitazone also inhibited chemotaxis of HUVEC.
Conclusion
Our study indicated that administration of the PPARγ agonist, pioglitazone enhances the effects of ABL TKI and is effective in suppression of angiogenesis, suggests that PPARγ agonist may possess promising clinical relevance as a candidate for treatment of Ph-positive leukemia patients.
Session topic: E-poster
Keyword(s): Acute lymphoblastic leukemia, Angiogenesis, Philadelphia chromosome
Type: Publication Only
Background
ABL tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib and dasatinib have demonstrated the potency against Philadelphia chromosome (Ph)-positive leukemia patients. However, resistance to ABL TKI can develop in chronic myeloid leukemia (CML) patients due to BCR-ABL point mutations and leukemia stem cells, because ABL TKIs cannot eradicate leukemia stem cells. Therefore, new approach against BCR-ABL mutant cells and LSCs may improve the outcome of Ph-positive leukemia patients. Peroxisome proliferator-activated receptors (PPARs) compose a superfamily of nuclear hormone receptors and regulate the transcription of target genes. Three subtypes of PPARs (α, γ and δ/β) have been identified. PPARγ is expressed not only adipose tissue but also cancer cells. The PPARγ agonist, pioglitazone was used for the treatment of diabetes patients. Recently, it has been reported that PPARγ agonist eradicate leukemia stem cells of CML patients (Prost S et al. Nature. 2015;525 :380-3).
Aims
We hypothesized that targeting PPARγ, in combination with ABL TKI, would result in enhanced therapeutic activity in Ph-positive leukemia cells including T315I mutation and primary samples.
Methods
In this study, we investigated the effect of PPARγ agonist, pioglitazone on Ph-positive leukemia cell lines (K562, NCO2, Ba/F3 BCR-ABL, Ba/F3 T315I) and primary samples.
Results
72 h treatment of pioglitazone did not exhibit cell growth inhibition against K562 cells.We found that mRNA of PPAR subunit, PPARα and PPARγ was increased after pioglitazone treatment. We examined the intracellular signaling after treatment of pioglitazone. We found phosphorylation of BCR-ABL and Crk-L was not reduced after pioglitazone treatment. In contrast, phospohorylation of AMP-activated protein kinase (AMPK) was increased and S6 ribosomal protein was reduced. We investigated the pioglitazone activity against T315I positive cells. Pioglitazone did not induce cell growth inhibition of Ba/F3 T315I cells. However, combined treatment of Ba/F3 T315I cells with ponatinib and high concentration of pioglitazone caused more cytotoxicity than each drug alone. Phosphorylation of BCR-ABL and Crk-L was not reduced. However, phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We also found that the treatment of ponatinib and pioglitazone exhibits cell growth inhibition against Ph-positive primary samples with T315I mutation. Phosphorylation of S6 ribosomal protein was reduced and AMPK phosphorylation and cleaved poly (ADP-ribose) polymerase (PARP) was increased after ponatinib and pioglitazone treatment. We next investigated the anti-angiogenic effects of PPARγ agonist on human umbilical vein endothelial cells (HUVEC). Pioglitazone inhibited tube formation of HUVEC (size, length and junction) in matrigel assay. Pioglitazone also inhibited chemotaxis of HUVEC.
Conclusion
Our study indicated that administration of the PPARγ agonist, pioglitazone enhances the effects of ABL TKI and is effective in suppression of angiogenesis, suggests that PPARγ agonist may possess promising clinical relevance as a candidate for treatment of Ph-positive leukemia patients.
Session topic: E-poster
Keyword(s): Acute lymphoblastic leukemia, Angiogenesis, Philadelphia chromosome
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