Cellular Effects of Troglitazone on YD15 Tongue Carcinoma Cells

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator–activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at G₀/G₁ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of p21(CIP1/WAF1) and p27(KIP1). In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

Troglitazone Enhances the Apoptotic Response of DLD-1 Colon Cancer Cells to Photodynamic Therapy

PURPOSE: The aim of this study was to investigate whether the peroxisomal proliferator-activated receptor gamma (PPARγ) ligand troglitazone in combination with photodynamic therapy (PDT) enhances the apoptotic response of DLD-1 colon cancer cells. MATERIALS AND METHODS: The effects of troglitazone, PDT, and troglitazone in combination with PDT on cell viability and apoptosis were assessed in DLD-1 cells. Cell viability and proliferation were evaluated using the tetrazolium-based MTT assay, and apoptosis was evaluated via cell staining with propidium iodide (PI) and annexin V-FITC. The levels of pro-caspase-3 were measured via Western blot analyses. RESULTS: Treatment of troglitazone and PDT induced the growth retardation and cell death of DLD-1 cells in a dose-dependent manner, respectively. The combination treatment significantly suppressed cell growth and increased the apoptotic response of DLD-1 and resulted in apoptosis rather than necrosis, as shown by PI/annexin V staining and degradation of procaspase-3. CONCLUSION: Conclusion: These results document the anti-proliferative and apoptotic activities of PDT in combination with the PPARγ ligand troglitazone and provide a strong rationale for testing the therapeutic potential of combination treatment in colon cancer.

Troglitazone Enhances the Apoptotic Response of DLD-1 Colon Cancer Cells to Photodynamic Therapy

PURPOSE: The aim of this study was to investigate whether the peroxisomal proliferator-activated receptor gamma (PPARγ) ligand troglitazone in combination with photodynamic therapy (PDT) enhances the apoptotic response of DLD-1 colon cancer cells. MATERIALS AND METHODS: The effects of troglitazone, PDT, and troglitazone in combination with PDT on cell viability and apoptosis were assessed in DLD-1 cells. Cell viability and proliferation were evaluated using the tetrazolium-based MTT assay, and apoptosis was evaluated via cell staining with propidium iodide (PI) and annexin V-FITC. The levels of pro-caspase-3 were measured via Western blot analyses. RESULTS: Treatment of troglitazone and PDT induced the growth retardation and cell death of DLD-1 cells in a dose-dependent manner, respectively. The combination treatment significantly suppressed cell growth and increased the apoptotic response of DLD-1 and resulted in apoptosis rather than necrosis, as shown by PI/annexin V staining and degradation of procaspase-3. CONCLUSION: Conclusion: These results document the anti-proliferative and apoptotic activities of PDT in combination with the PPARγ ligand troglitazone and provide a strong rationale for testing the therapeutic potential of combination treatment in colon cancer.

The Inhibitory Effect of Testosterone on PPARγ-induced Adipogenesis

BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) plays a major role in adipocyte differentiation. Testosterone is well known for inhibiting adipocyte metabolism in men. To investigate the inhibitory mechanism of testosterone on adipogenesis, this study evaluated the effects of testosterone on PPARγ expression and activity in adipocytes using in vitro approaches. METHODS: After differentiated 3T3-L1 adipocytes were treated with PPARγ agonist troglitazone and sex hormone testosterone, the effects of testosterone on troglitazone-induced triglyceride accumulation and expression of genes involved in adipogenesis were investigated. We also investigated whether testosterone regulates troglitazone-induced PPARγreporter activity in 3T3-L1 preadipocytes. RESULTS: Testosterone decreased triglyceride accumulation in differentiated 3T3-L1 cells compared with the vehicle treated control group. Testosterone also decreased the expression of PPARγ mRNA as well as PPARγ dependent adipocyte-specific genes, such as adipocyte fatty acid binding protein and tumor necrosis factor α. Moreover, testosterone treatment inhibited triglyceride accumulation, and the expression of PPARγ and adipocyte-specific genes caused by troglitazone in differentiated 3T3-L1 cells. Testosterone decreased troglitazone-induced PPARγ reporter activity. Also, treatment with testosterone led to an inhibition of troglitazone-induced PPARγ reporter activity in PPARγ and androgen receptor (AR) expressed 3T3-L1 preadipocytes. CONCLUSION: These results suggest that testosterone interferes with the actions of PPARγ on adipogensis by an AR-dependent component. In addition, this study may have provided valuable molecular and biological insights regarding testosterone therapy in obese hypogonadal men.

Effects of Skp2 overexpression on sensitivity of troglitazone in breast cancer cells / 国际检验医学杂志

Objective To investigate the effects of Skp2 overexpression on the sensitivity of troglitazone (TRG) in breast cancer cells and to devote to develop a novel drug for increasing the patient survival rate and eventually reaching the cure goal .Methods The transcription activities of PPARγ were analyzed on peroxisome proliferators response element(PPRE) luciferase reporter .The flow cytometry analysis and CCK‐8 assay were adopted to study that overexpression of Skp2 was associated with resistance to TRG‐mediated inhibition growth and apoptosis of breast cancer cells .Results Our study found that overexpression of Skp2 inhibi‐ted the transcriptional activity of the endogenous PPARγ and resisted to TRG‐mediated inhibition growth and apoptosis of breast cancer cells .Conclusion Overexpressed Skp2 breast cancer cells is able to be resistant to TRG‐induced sensitivity of breast cancer cells .Furthermore down‐regulating Skp2 will significantly enhance the growth inhibition of TRG on breast cancer cells .

Effect of resveratrol as an antioxidant on oxidative damage to HepaRG cells induced by troglitazone / 军事医学

Objective To explore the effect of resveratrol ( Rev) as an antioxidant on oxidative damage to HepaRG cells induced by troglitazone ( Tro).Methods Cells were divided into five groups: control ( RPMI 1640 only with 0.1%DMSO), Tro(50 μmol/L), Tro(50 μmol/L) +Rev(15 μmol/L), Tro(50 μmol/L) +Rev(7.5 μmol/L) and Tro (50 μmol/L)+Rev(3.75 μmol/L) groups.MTT assay was performed to detect the viability of Rev-treated, Tro-treated and Rev with 50 μmol/L Tro-treated HepaRG cells.After 48 hours, the level of reactive oxygen species (ROS) and lipid oxidation ( malondialdehyde , MDA ) , degree of apoptosis , total antioxidant capacity , activity of hydrogenperoxidase (catalase, CAT), glutathione peroxidase (GSH-px) and superoxide dismutase(SOD)of these groups were identified. Results Tro could obviously cause HepaRG cells to produce oxidative stress .Compared with control group ,ROS and lipid peroxidation ( MDA) levels and the rate of apoptosis and necrosis in Tro-treated group were significantly increased ( P<0.05),total antioxidant capacity greatly reduced (P<0.05),and the activity of CAT,GSH-px and SOD was decreased (P<0.05).After adding various concentrations of Rev interaction , ROS and MDA production volume decreased (P < 0.05), and the apoptosis and necrosis rate correspondingly declined (P<0.05).Total antioxidant capacity of the cells and the activity of the three antioxidant enzymes were increased (P<0.05), and there was a dose-dependent relationship. Conclusion Tro can cause HepaRG cells to produce significant oxidative stress while Rev can significantly improve the oxidative damage of Tro to HepaRG cells .

Effect of troglitazone on radiation sensitivity in cervix cancer cells

PURPOSE: Troglitazone (TRO) is a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist. TRO has antiproliferative activity on many kinds of cancer cells via G1 arrest. TRO also increases Cu2+/Zn2+-superoxide dismutase (CuZnSOD) and catalase. Cell cycle, and SOD and catalase may affect on radiation sensitivity. We investigated the effect of TRO on radiation sensitivity in cancer cells in vitro. MATERIALS AND METHODS: Three human cervix cancer cell lines (HeLa, Me180, and SiHa) were used. The protein expressions of SOD and catalase, and catalase activities were measured at 2-10 microM of TRO for 24 hours. Cell cycle was evaluated with flow cytometry. Reactive oxygen species (ROS) was measured using 2',7'-dichlorofluorescin diacetate. Cell survival by radiation was measured with clonogenic assay. RESULTS: By 5 microM TRO for 24 hours, the mRNA, protein expression and activity of catalase were increased in all three cell lines. G0-G1 phase cells were increased in HeLa and Me180 by 5 microM TRO for 24 hours, but those were not increased in SiHa. By pretreatment with 5 microM TRO radiation sensitivity was increased in HeLa and Me180, but it was decreased in SiHa. In Me180, with 2 microM TRO which increased catalase but not increased G0-G1 cells, radiosensitization was not observed. ROS produced by radiation was decreased with TRO. CONCLUSION: TRO increases radiation sensitivity through G0-G1 arrest or decreases radiation sensitivity through catalase-mediated ROS scavenging according to TRO dose or cell types. The change of radiation sensitivity by combined with TRO is not dependent on the PPARgamma expression level.

Troglitazone reduces the inhibitory effect of sirolimus on premature 3T3-L1 cell's function / 中华肾脏病杂志

Objective To investigate the effects of troglitazone on cholesterol homeostasis and secretion of 3T3-L1 cells by sirolimus and the underlying mechanisms. Methods In vitro cultured 3T3-L1 cells were divided into control group,sirolimus (100 nmol/L) group,sirolimus(100nmol/L)+ troglitazone (10 μmol/L) group and troglitazone (10 μmol/L) group.High performance liquid chromatography (HPLC) was used to measure intracellular cholesterol accumulation.ELISA was used to measure leptin excretion.Quantitative real-time PCR and Western blotting were used to examine mRNA and protein expression of PPARγ. Results Free cholesterol of sirolimus +troglitazone group was 1.19 times of sirolimus group (P＜0.05).The leptin secretion levels of control group,sirolimus group,sirolimus+troglitazone group and troglitazone group were (19.02±0.52) μg/L,(15.62±0.47) μg/L,(16.45±0.51) μg/L,(18.07±0.66) μg/L,respectively.And the leptin secretion level of sirolimus+ troglitazone group was 1.05 times of sirolimus group (P＜0.05).The PPARγmRNA expressions of sirolinus group,sirolimus + troglitazone group and troglitazone group were 0.60±0.14,1.12±0.27,1.30±:0.14 folds of control,and the PPARγ mRNA expression of sirolimus + troglitazone group was higher than that of sirolimus group (P＜0.05).PPARγ protein expression had the same tendency. Conclusion Troglitazone reduces the inhibitory effect of sirolimus on PPARγ transactivation and the inhibitory effect of sirolimus on 3T3-L1 cells differentiation and adipogenesis.

Over-expression of PTEN Involved in Troglitazone-induced Apoptosis in Human Osteosarcoma Cells / 대한골관절종양학회지

PURPOSE: We investigated the effects of phosphatase and tensin homologue deleted on chromosome 10 gene phosphatase and tensin homologue deleted on chromosome 10 gene (PTEN) expression on the cell proliferation and on the responsiveness of troglitazone in osteosarcoma cells. MATERIALS AND METHODS: Western blotting alnalysis was performed to detect the expression of PTEN in U-2OS cells treated with troglitazone. WST (water-soluble tetrazolium) assay was used to evaluate cell proliferation. Flow cytometry was used to determine cell apoptosis. Further, transfection of wild-type PTEN plasmid DNA was used to upregulate PTEN expression. RESULTS: Troglitazone treatment induced growth inhibition of U2-OS cells in a dose- and time-dependent manner. Troglitazone increased the expression of PTEN in a dose-dependent manner. PTEN upregulation induced by troglitazone treatment resulted in cell growth inhibition and apoptosis in U-2OS cells. PTEN over-expression by plasmid transfection enhanced these effects of troglitazone. Moreover, no changes were observed in the mutant type-PTEN group. CONCLUSION: Upregulation of PTEN is involved in the inhibition of cell growth and induction of cell apoptosis by troglitazone. Further, PTEN over-expression can cause cell growth inhibition in osteosarcoma cells and these cell growth inhibitions could be enhance by troglitazone treatment.

Effect of troglitazone on insulin secretion in pancreatic β-cells and its mechanism / 中华内分泌代谢杂志

The effect of troglitazone on glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells and its mechanism were investigated.10 μmol/L troglitazone had no effect on basal insulin secretion,but significantly decreased GSIS and stimulated AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylations (all P<0.01).These reactions were completely reversed by AMPK inhibitor compound C,suggesting that the troglitazone acutely inhibits insulin secretion via stimulating AMPK activity in beta cells.

Troglitazone inhibits proliferation of GH3 cell in vitro / 第二军医大学学报

Objective: To study the anti-proliferation effects of thiazolidinedione compounds-troglitazone, which is a high affinity ligand of PPAR-γ, on rat pituitary adenoma GH3 cell line and explore the related mechanisms. Methods: GH3 cells were separately treated with troglitazone (10-7, 10-6 and 10-5 mol/L), dimethyl sulfoxide (DMSO) (DMSO control group) and phenol red- and serum-free F-12 medium (blank group). MTT was used to examine the cell growth in each group and FACS was used to detect the distribution of cell cycle. Semi-quantitative RT-PCR method was utilized to determine the expression of CyclinDi mRNA. ANOVA was used for statistical analysis. Results: The 72 h treatment with troglitazone inhibited GH3 cell proliferation in a dose-dependent manner. The treatment also induced cell cycle arrest in G1/S phase and significantly decreased the expression of CyclinD1 mRNA as compared to the other 2 groups (P< 0.05). Conclusion: Troglitazone can obviously inhibit the proliferation of GH3 cells; the molecular mechanism may be the decrease of CyclinD1 mRNA due to binding to PPAR-γ.

Influence of troglitazone on proliferation of human liver cancer cell line HepG2 in vitro and on β-catenin signaling pathway / 第二军医大学学报

Objective: To investigate the influence of troglitazone, a potent peroxisome proliferator-activated receptor (PPAR) gamma agonist, on proliferation and β-catenin signaling pathway of human liver cancer cell line HepG2 in vitro, and to discuss its possible anti-cancer mechanism. Methods: HepG2 cells were cultured in vitro and the cell growth was assessed by MTT assay after exposure to different concentrations of troglitazone (5, 10, 20, 40, 80 and 100 μmol/L) for 120 h, and the results were compared with that of the control cells (cultured normally). Flow cytometry was used to assess cell cycle of HepG2 cells treated with troglitazone at 10 μmol/L and of normal control cells. The subcellular location of β-catenin was investigated by immunocytochemistry in troglitazone (10 μmol/L)-treated and control cells. Expression of cyclin D1 and c-myc proteins was examined by Western blotting assay. Results: MTT assay demonstrated that, after treatment with 5, 10, 20, 40, 80 and 100 μmol/L of troglitazone, the cell survival rates were (96.8±1.2)%, (53.4±1.2)%, (42.3±1.2)%, (31.4±1.0)%, (13.6± 0.8)% and (9.6±0.7)%, respectively. Compared with control cells, cells treated with 10 μmol/ L troglitazone showed an increased proportion of cells at the G0/G1 phase ([67.6±0.5]% vs [56.3±1.5]%, P<0.01) and decreased proportion of cells at the S phase ([20.6±0.5]% vs [25±1.0]%, P<0. 01). β-catenin was located in the nucleus of the control cells and in the cytoplasm of the troglitazone-treated cells. Western blotting analysis showed that the expression of c-myc and cyclin D1 proteins in troglitazone-treated cells was lower than that in the control cells. Conclusion: Troglitazone can inhibit the proliferation of HepG2 cells in a dose-dependent manner, which may be associated with regulation of the β-catenin signaling pathway and inhibition of target protein expression.

The Effect of Troglitazone on Thermal Sensitivity in Uterine Cervix Cancer Cells / 대한방사선종양학회지

PURPOSE: Troglitazone (TRO), a PPAR-gamma agonist, can reduce heat shock protein (HSP) 70 and increase the antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, which might affect thermal sensitivity. Here, we investigated whether TRO modifies thermal sensitivity in uterine cervical cancer cells, which is most commonly treated by hyperthermia (HT). MATERIALS AND METHODS: HeLa cells were treated with 5microM TRO for 24 hours before HT at 42degrees C for 1 hour. Cell survival was analyzed by clonogenic assay. The expression of HSPs was analyzed by Western blot. SOD and catalase activity was measured and reactive oxygen species (ROS) was measured using 2',7'-dichlorofluorescin diacetate and dihydroethidium. RESULTS: The decreased cell survival by HT was increased by preincubation with TRO before HT. Expression of HSP 70 was increased by HT however, it was not decreased by preincubation with TRO before HT. The decreased Bcl-2 expression by HT was increased by preincubation with TRO. SOD and catalase activity was increased by 1.2 and 1.3 times,respectively with TRO. Increased ROS by HT was decreased by preincubation with TRO. CONCLUSION: TRO decreases thermal sensitivity through increased SOD and catalase activity, as well as scavenging ROS in HeLa cells.

Reversal of P-glycoprotein-mediated Multidrug Resistance in SGC7901/VCR Cells by PPARγ Activation by Troglitazone / 华中科技大学学报（医学）（英德文版）

Over-expression of P-glycoprotein(P-gp),an ATP-dependent drug efflux pump,represents one of the major mechanisms that contribute to multidrug resistance(MDR)in cancer cells.This study examined the effects of troglitazone,a ligand of peroxisome proliferator-activated receptor gamma (PPARγ),on P-gp-mediated MDR in SGC7901/VCR cells(a vincristine-resistant human gastric cancer cell line).The expression of P-gp was detected by RT-PCR and Westem blotting,respectively.The SGC7901/VCR cells were treated with 0.1 mg/L vincristine(VCR)alone or in combination with 1,5,10 μmol/L troglitazone for 24 h.PPARγ was measured by electrophoretic mobility shift assay(EMSA).The intracellular concentration of Rhodamine123(Rh123,a fluorescent P-gp substrate)was assayed to evaluate the activity of P-gp.The cell cycle and apoptosis were measured by flow cytometry.The results showed that the P-gp was increasingly expressed in SGC7901,BGC823 and SGC7901/VCR cells in turn,suggesting that MDR in the SGC7901/VCR cells was mediated by the increased expression of P-gp.In the SGC7901/VCR cells,the expression level of total PPARγ was increased,however,the protein level and activity of PPARγ,in the nuclei of cells decreased significantly.Troglitazone elevated the PPARγ,activity in SGC7901/VCR cells in a dose-dependent manner.Troglitazone decreased the P-gp expression and markedly enhanced the accumulation of Rh123 in SGC7901/VCR cells in a dose-dependent manner.We also found that troglitazone significantly increased the percentage of SGC7901/VCR cells in the G2/M phase and decreased the cell percentage in G1 and S phase in a dose-dependent manner.Troglitazone significantly increased the apoptotic rate of SGC7901/VCR cells treated by VCR or ADR in a dose-dependent manner.It was concluded that P-gp-overexpressed SGC7901/VCR cells have minor endogenous PPARγ activity.Elevation of the PPARγ activity by troglitazone can reverse P-gp-mediated MDR via down-regulating the expression and activity of P-gp in SGC7901/VCR cells.It was suggested that troglitazone can dramatically enhance the sensitivity of P-gp-mediated MDR cancer cells to chemotherapeutic agents.

Effects of troglitazone on the proliferation and differentiation of HepG2 cells / 中华消化外科杂志

Objective To examine the effects of a peroxisome proliferator-activated receptor γ ligand troglitazone on the proliferation and differentiation of HepG2 cells. Methods After the pretreatment of HepG2 cells with troglitazone, MTT and flow cytometry were used to analyze the proliferation and cell cycle of HepG2 cells, respectively. Immunocytochemistry, bromocresol green dye-binding method and chemiluminessence immunosorbent assay was used to determine E-cadherin, albumin and AFP, respectively. The expression of cyclin D1 and c-myc protein were detected by Western blot. Results Troglitazone inhibited the proliferation of HepG2 cells in a concentration-dependent manner and arrested HepG2 ceils at the G0>/G1> phase. After pretreated with troglitazone, HepG2 cells showed E-cadherin expression, a decreased expression of cyclin D1 and c-myc protein, a reduction of AFP level and a dramatic increase of albumin level. Conclusions Troglitazone inhibits proliferation and induces differentiation of HepG2 cells, the mechanism of which might be attributable to the down-regulation of cyclin D1 and c-myc expression.

Troglitazone inhibits rat pituitary adenoma GH3 cell growth by activating peroxisome proliferator-activated receptor-gamma to suppress cyclin DI transcription / 中华神经医学杂志

Objective To study the inhibitory effects of troglitazone on the proliferation of rat pituitary adenoma GH3 cell line in vitro and explore the mechanisms. Methods GH3 cells were treated with troglitazone at different concentrations (1×10-7, 1×10-6and 1×10-5 mol/L), dimethyl sulfoxide (DMSO) (DMSO control group) or phenol red- and serum-free F-12 medium (blank control group). MTT assay and flow cytometry was used to detect the cell growth and the cell cycle distribution after the treatment, respectively. Semi-quantitative RT-PCR was performed to detect the expression of cyclin D1 mRNA. Results Troglitazone treatment for 72 h significantly inhibited the cell proliferation and induced obvious G1/S cell cycle arrest and cell death. Compared to those in the blank control and DMSO-treated cells, troglitazone also significantly decreased the expression ofcyclin 1I mR_NA in the GH3 cells in a concentration-dependent manner (P<0.05). Conclusion Troglitazone can obviously inhibit the proliferation of GH3 cells possibly through the mechanism of decreasing cyclin D1 mRNA after its binding to peroxisome proliferator-activated receptor-γ, which induces G1 cell-cycle arrest and promotes cell death.

Effect of Troglitazone on Expression of Adhesion Molecules and eNOS in Human Saphenous Vein Gaft / 华中科技大学学报（医学）（英德文版）

To investigate whether peroxisome proliferators-activated receptor-y (PPARγ) ligand Troglitazone can reduce endothelial injury and activation during storage of harvested saphenous vein grafts. Segments of human saphenous vein graft were collected from 9 patients undergoing coronary bypass surgery and then divided into two equal parts of control and test specimens, were stored in ei-ther heparinized blood (control group) or heparinized blood containing 20 μmol/L troglitazone (test group) for 1 h at room temperature. Tissue distribution and protein expression of VCAM-1, ICAM-1, and endothelial nitric oxide synthase (eNOS) were compared using immunohistochemistry and West-ern blot analysis. Myeloperoxidase (MPO) activity, a marker of neutrophil sequestration in human saphenous vein grafts, was also measured in each group. The expression of ICAM-1 (753±132 versus 7201±934; P<0.01) , VCAM-1 (3731±294 versus 8292±793; P<0.01), and MPO activity (1.52±0.42 U/g, 5.04±1.26 U/g P<0.01) were significantly lower in test group. In contract, eNOS expression (7983±834 versus 3989±1008; P<0.01) was significantly higher in test group. PPARγ ligand troglita- zone might reduce endothelial injury during the storage period of human saphenous vein grafts.

Effects of troglitazone on cytokines induced expression of ICAM-1 in human mesangial cell / 重庆医科大学学报

Objective:To investigate the effects of troglitazone on cell proliferation and expression of intercellular adhesion molecule-1(ICAM-1) induced by tumor necrosis factor-?(TNF-?) in human mesangial cells.Methods:Human mesangial cells were cultured in RPMI-1640 media containing TNF-? with or without troglitazone.Cell proliferation was assessed by MTT;the mRNA and protein expression of ICAM-1 were measured by RT-PCR and ELISA;the protein expression of NF-?B was measured by immunohistochemistry.Results:Troglitazone inhibited the proliferation of mesangial cell.The mRNA and protein expression of ICAM-1 of the cell induced by TNF-? increased significantly(P

Synergistic Apoptotic Effect of Combination Treatment with Troglitazone and COX-2 Inhibitor in Glioma Cells

BACKGROUND: The use of troglitazone (a PPARgamma ligand) and COX-2 inhibitor have been intensively studied for inhibition of tumor growth in cancer treatment, but the anti-tumor effect with a combination of these agents for cancer has not yet been studied. The aim of this study was to determine if low concentrations of troglitazone with COX-2 inhibitor in combination would cause significant cytotoxicity in glioma cells. METHODS: The effects of co-treatment with troglitazone and COX-2 inhibitor on cell growth and apoptosis were assessed by use of trypan blue exclusion and a DNA fragmentation assay. A western blot was used to analyze the apoptotic signaling for the expression of bcl-2, bax, PARP and p21 proteins. RESULTS: A low dose of troglitazone (5micrometer) and COX-2 inhibitor (5micrometer) strongly enhanced the cell growth inhibition and apoptosis in glioma cells when compared to a low dose of each drug alone. Western blotting analysis showed a decreased expression of bcl-2 and PARP proteins. In contrast, the bax protein level was increased. CONCLUSIONS: The combination of troglitazone and COX-2 inhibitor in a low dose elicits synergistic cytotoxicity in glioma cells. Our study also demonstrates that down regulation of bcl-2, fragmentation of PARP protein and increased expression of bax protein were accompanied by co-treatment with troglitazone and the COX-2 inhibitor.

Antiproliferative Effect of Phenylbutyrate in AsPC-1 Pancreatic Cancer Cell Line

PURPOSE: Phenylbutyrate is an effective redifferentiating agent in several human cancers. Recently phenylbutyrate has been reported to inhibit histone deacetylase activity. We investigated the effects of sodium 4-henylbutyrate (Na-4-PB) on cell proliferation in a human pancreatic cancer cell line. METHODS: A human pancreatic cancer cell line, Aspc-1 was purchased from Korean Cell Line Bank. Antiproliferative effects of sodium 4-phenylbutyrate were measured by MTT assay and their mechanisms were evaluated by apoptosis assay and cell cycle analysis. RESULTS: After 3 days of treatment with Na-4-PB at the concentration of 2.5, 5, 7.5, and 10 mM, relative growth inhibition compared to control was 21.3+/-8.3% (mean+/-SD), 37.8+/-2.3%, 46.7+/-0.5%, and 56.7+/-1.7% respectively (p < 0.05). Antiproliferative effect of Na-4-PB was also time-dependent. Combination treatment with Na-4-PB and troglitazone, a PPARg agonist, increased antiproliferative effects but was not synergistic. After 48 hour treatment with Na-4-PB, early apoptotic cell population in control, 2.5, and 5 mM of Na-4-PB was 29.6%, 44.2%, and 65.9%, respectively. After 24 hour treatment with Na-4- PB, G0/G1 phase population in control, 2.5, and 5 mM of Na-4-PB was 55.0%, 67.4%, and 65.8%, respectively. CONCLUSION: Na-4-PB inhibited pancreatic cancer cell proliferation by inducing apoptosis and cell cycle arrest at G0/G1 phase in time- and dose-dependent manner. Combination treatment with Na-4-PB and other chemotherapeutic agents such as troglitazone, a PPARg agonist, can enhance antiproliferative effects. Na-4-PB might be a promising potential therapeutic agent for patients with pancreatic cancer.