Contributions
Abstract: PB1898
Type: Publication Only
Background
Imatinib, the most affordable and effective tyrosine kinase inhibitor for chronic phase chronic myeloid leukaemia is becoming resistance in many patients. Efforts are being made to combine the imatinib with other molecules to dodge the resistance and to get deeper molecular responses. This concept has been substantiated by recent phase 2 trial of imatinib in combination with well-known thiazolidinedione (TZD), pioglitazone. TZDs like rosiglitazone, pioglitazone once known for their potent antidiabetic action were withdrawn from the market due to their ability to cause cardiotoxicity and bladder cancer respectively and these side effects have been attributed to their full agnostic activity towards peroxisome proliferative activated receptor γ (PPAR γ).
Aims
To circumvent the PPARγ activation and thus toxicity, we design and synthesized novel TZDs (3a-3y) and studied their in-vitro and in-vivo antiproliferative activity in combination with imatinib.
Methods
Synthetic scheme was standardized and molecules 3a-3y were synthesized as per standard scheme. Molecules were characterized using IR, 1H NMR, 13C NMR and mass spectrometry. Antiproliferative activity was carried out using SRB assay on various leukemic cell lines. Moieties were also screened for their toxicity on non-transformed hepatocyte using MTT assay. Cell cycle inhibition assay was carried out using propidium iodide and FACS. Inhibition of proliferative and cell cycle markers, PCNA and cyclin D1 inhibition was checked by western blot analysis. PPARγ activation assay was carried out using ELISA test. In-vivo activity of 3t and 3x in combination with imatinib was carried in mice xenograft model with the permission from institutional ethical committee.
Results
The IR, 1H NMR, 13C NMR and mass spectra data confirmed the structure of molecules. The anti-proliferative activity of molecules was in the range of 0.19-70 µM on k-562 cell line. The MTT assay confirmed the safety of all moieties on untransformed hepatocytes. Molecules bearing significant anti-proliferative activity were also found to arrested the cells in G0/G1 phase in dose and time dependent manner. Two molecules 3t and 3x emerged as a lead entities. Maximum tolerated dose analysis revealed that molecules were tolerated up to 2000 mg/kg. These two lead compounds found to significantly reduce the tumour volume in combination with imatinib.
Conclusion
In the developing countries like India, Imatinib is the only affordable tyrosine kinase inhibitor (TKI). Compared to 2nd generation TKIs, imatinib is well tolerated and has a proven efficacy. These novel agents when combined with imatinib will help to get deeper responses and overcome resistance to imatinib. Further investigation on leukemic stem cell and long term toxicity of these molecule are under investigation.
Session topic: 7. Chronic myeloid leukemia – Biology & Translational Research
Keyword(s): Cell cycle, Chronic myeloid leukemia, Cyclin D1, imatinib
Abstract: PB1898
Type: Publication Only
Background
Imatinib, the most affordable and effective tyrosine kinase inhibitor for chronic phase chronic myeloid leukaemia is becoming resistance in many patients. Efforts are being made to combine the imatinib with other molecules to dodge the resistance and to get deeper molecular responses. This concept has been substantiated by recent phase 2 trial of imatinib in combination with well-known thiazolidinedione (TZD), pioglitazone. TZDs like rosiglitazone, pioglitazone once known for their potent antidiabetic action were withdrawn from the market due to their ability to cause cardiotoxicity and bladder cancer respectively and these side effects have been attributed to their full agnostic activity towards peroxisome proliferative activated receptor γ (PPAR γ).
Aims
To circumvent the PPARγ activation and thus toxicity, we design and synthesized novel TZDs (3a-3y) and studied their in-vitro and in-vivo antiproliferative activity in combination with imatinib.
Methods
Synthetic scheme was standardized and molecules 3a-3y were synthesized as per standard scheme. Molecules were characterized using IR, 1H NMR, 13C NMR and mass spectrometry. Antiproliferative activity was carried out using SRB assay on various leukemic cell lines. Moieties were also screened for their toxicity on non-transformed hepatocyte using MTT assay. Cell cycle inhibition assay was carried out using propidium iodide and FACS. Inhibition of proliferative and cell cycle markers, PCNA and cyclin D1 inhibition was checked by western blot analysis. PPARγ activation assay was carried out using ELISA test. In-vivo activity of 3t and 3x in combination with imatinib was carried in mice xenograft model with the permission from institutional ethical committee.
Results
The IR, 1H NMR, 13C NMR and mass spectra data confirmed the structure of molecules. The anti-proliferative activity of molecules was in the range of 0.19-70 µM on k-562 cell line. The MTT assay confirmed the safety of all moieties on untransformed hepatocytes. Molecules bearing significant anti-proliferative activity were also found to arrested the cells in G0/G1 phase in dose and time dependent manner. Two molecules 3t and 3x emerged as a lead entities. Maximum tolerated dose analysis revealed that molecules were tolerated up to 2000 mg/kg. These two lead compounds found to significantly reduce the tumour volume in combination with imatinib.
Conclusion
In the developing countries like India, Imatinib is the only affordable tyrosine kinase inhibitor (TKI). Compared to 2nd generation TKIs, imatinib is well tolerated and has a proven efficacy. These novel agents when combined with imatinib will help to get deeper responses and overcome resistance to imatinib. Further investigation on leukemic stem cell and long term toxicity of these molecule are under investigation.
Session topic: 7. Chronic myeloid leukemia – Biology & Translational Research
Keyword(s): Cell cycle, Chronic myeloid leukemia, Cyclin D1, imatinib