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Autonomous inhibition of apoptosis correlates with responsiveness of colon carcinoma cell lines to ciglitazone.

Baron DM, Kaindl U, Haudek-Prinz VJ, Bayer E, Röhrl C, Gerner C, Marian B - PLoS ONE (2014)

Bottom Line: Resistance to therapy is common and often results in patients succumbing to the disease.To verify the data we performed shotgun analysis using the same treatment procedure as in 2D-experiments.Biological functions of the identified proteins were mainly associated with apoptosis regulation, chaperoning, intrinsic inflammation, and DNA repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine I, Clinic for Internal Medicine I, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria; Department of Anesthesia, General Intensive Care, and Pain Management Medical, Medical University of Vienna, Vienna, Austria.

ABSTRACT
Colorectal cancer is a leading cause of mortality worldwide. Resistance to therapy is common and often results in patients succumbing to the disease. The mechanisms of resistance are poorly understood. Cells basically have two possibilities to survive a treatment with potentially apoptosis-inducing substances. They can make use of their existing proteins to counteract the induced reactions or quickly upregulate protective factors to evade the apoptotic signal. To identify protein patterns involved in resistance to apoptosis, we studied two colorectal adenocarcinoma cell lines with different growth responses to low-molar concentrations of the thiazolidinedione Ciglitazone: HT29 cells underwent apoptosis, whereas SW480 cells increased cell number. Fluorescence detection and autoradiography scans of 2D-PAGE gels were performed in both cell lines to assess protein synthesis and turnover, respectively. To verify the data we performed shotgun analysis using the same treatment procedure as in 2D-experiments. Biological functions of the identified proteins were mainly associated with apoptosis regulation, chaperoning, intrinsic inflammation, and DNA repair. The present study suggests that different growth response of two colorectal carcinoma cell lines after treatment with Ciglitazone results from cell-specific protein synthesis and differences in protein regulation.

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Cell viability and mitochondrial membrane potential after treatment with thiazolidinediones.Cell viability was assessed by neutral red uptake in SW480 and HT29 cells treated with increasing concentrations of (A) Ciglitazone or (B) Troglitazone for 6 and 24 hours. *p<0.05, values of HT29 cells differ from those of SW480 cells. Mitochondrial membrane potential (Δψm) was assessed by JC-1 FACS analysis in (C) HT29 and (D) SW480 cells treated with increasing concentrations of Ciglitazone for 24 and 48 hours. *p<0.05, values at 48 hours differ from those at 24 hours. #p<0.05, values at indicated concentrations differ from baseline.
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pone-0114158-g001: Cell viability and mitochondrial membrane potential after treatment with thiazolidinediones.Cell viability was assessed by neutral red uptake in SW480 and HT29 cells treated with increasing concentrations of (A) Ciglitazone or (B) Troglitazone for 6 and 24 hours. *p<0.05, values of HT29 cells differ from those of SW480 cells. Mitochondrial membrane potential (Δψm) was assessed by JC-1 FACS analysis in (C) HT29 and (D) SW480 cells treated with increasing concentrations of Ciglitazone for 24 and 48 hours. *p<0.05, values at 48 hours differ from those at 24 hours. #p<0.05, values at indicated concentrations differ from baseline.

Mentions: Several research groups have reported apoptosis- and differentiation-inducing effects of PPAR-γ activators in colorectal cancer cell lines [34], [35]. To confirm these data we performed neutral red viability assays after incubation of HT29 and SW480 cells with TZDs. In HT29 cells, CIG induced a dose-dependent decrease of cell number after 6 and 24 hours (Fig. 1A). Surprisingly, in SW480 cells concentrations of CIG less than 5 µM, which is around the published EC50 for CIG binding to the PPAR-γ, caused a small but highly reproducible increase in cell number. These effects of CIG were potentiated even further after 48 and 72 hours in both cell lines (data not shown). The effects of TRO on cell number were similar. Incubation of HT29 cells with TRO caused a dose-dependent decrease of cell number after 6 and 24 hours (Fig. 1B). In SW480 cells, cell numbers were consistently increased by about 10% at 0.5 µM, which is the EC50 for TRO.


Autonomous inhibition of apoptosis correlates with responsiveness of colon carcinoma cell lines to ciglitazone.

Baron DM, Kaindl U, Haudek-Prinz VJ, Bayer E, Röhrl C, Gerner C, Marian B - PLoS ONE (2014)

Cell viability and mitochondrial membrane potential after treatment with thiazolidinediones.Cell viability was assessed by neutral red uptake in SW480 and HT29 cells treated with increasing concentrations of (A) Ciglitazone or (B) Troglitazone for 6 and 24 hours. *p<0.05, values of HT29 cells differ from those of SW480 cells. Mitochondrial membrane potential (Δψm) was assessed by JC-1 FACS analysis in (C) HT29 and (D) SW480 cells treated with increasing concentrations of Ciglitazone for 24 and 48 hours. *p<0.05, values at 48 hours differ from those at 24 hours. #p<0.05, values at indicated concentrations differ from baseline.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263530&req=5

pone-0114158-g001: Cell viability and mitochondrial membrane potential after treatment with thiazolidinediones.Cell viability was assessed by neutral red uptake in SW480 and HT29 cells treated with increasing concentrations of (A) Ciglitazone or (B) Troglitazone for 6 and 24 hours. *p<0.05, values of HT29 cells differ from those of SW480 cells. Mitochondrial membrane potential (Δψm) was assessed by JC-1 FACS analysis in (C) HT29 and (D) SW480 cells treated with increasing concentrations of Ciglitazone for 24 and 48 hours. *p<0.05, values at 48 hours differ from those at 24 hours. #p<0.05, values at indicated concentrations differ from baseline.
Mentions: Several research groups have reported apoptosis- and differentiation-inducing effects of PPAR-γ activators in colorectal cancer cell lines [34], [35]. To confirm these data we performed neutral red viability assays after incubation of HT29 and SW480 cells with TZDs. In HT29 cells, CIG induced a dose-dependent decrease of cell number after 6 and 24 hours (Fig. 1A). Surprisingly, in SW480 cells concentrations of CIG less than 5 µM, which is around the published EC50 for CIG binding to the PPAR-γ, caused a small but highly reproducible increase in cell number. These effects of CIG were potentiated even further after 48 and 72 hours in both cell lines (data not shown). The effects of TRO on cell number were similar. Incubation of HT29 cells with TRO caused a dose-dependent decrease of cell number after 6 and 24 hours (Fig. 1B). In SW480 cells, cell numbers were consistently increased by about 10% at 0.5 µM, which is the EC50 for TRO.

Bottom Line: Resistance to therapy is common and often results in patients succumbing to the disease.To verify the data we performed shotgun analysis using the same treatment procedure as in 2D-experiments.Biological functions of the identified proteins were mainly associated with apoptosis regulation, chaperoning, intrinsic inflammation, and DNA repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine I, Clinic for Internal Medicine I, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria; Department of Anesthesia, General Intensive Care, and Pain Management Medical, Medical University of Vienna, Vienna, Austria.

ABSTRACT
Colorectal cancer is a leading cause of mortality worldwide. Resistance to therapy is common and often results in patients succumbing to the disease. The mechanisms of resistance are poorly understood. Cells basically have two possibilities to survive a treatment with potentially apoptosis-inducing substances. They can make use of their existing proteins to counteract the induced reactions or quickly upregulate protective factors to evade the apoptotic signal. To identify protein patterns involved in resistance to apoptosis, we studied two colorectal adenocarcinoma cell lines with different growth responses to low-molar concentrations of the thiazolidinedione Ciglitazone: HT29 cells underwent apoptosis, whereas SW480 cells increased cell number. Fluorescence detection and autoradiography scans of 2D-PAGE gels were performed in both cell lines to assess protein synthesis and turnover, respectively. To verify the data we performed shotgun analysis using the same treatment procedure as in 2D-experiments. Biological functions of the identified proteins were mainly associated with apoptosis regulation, chaperoning, intrinsic inflammation, and DNA repair. The present study suggests that different growth response of two colorectal carcinoma cell lines after treatment with Ciglitazone results from cell-specific protein synthesis and differences in protein regulation.

Show MeSH
Related in: MedlinePlus