The non-genomic effects of high doses of Rosiglitazone on cell growth and apoptosis in cultured monocytic cells

Peroxisome Proliferator-Activated Receptor gamma (PPARγ) is a ligand-activated transcription factor which belongs to the nuclear hormone superfamily and has multiple pharmacological ligands called Thiazolidinediones (TZDs). TZDs are a class of drugs used in the treatment of type 2 diabetic patients. Rosiglitazone is one such TZD, and is used clinically to treat type 2 diabetes. In this study, the effect of Rosiglitazone on cell growth and apoptosis in cultured monocytic monomac 6 (MM6) cells was investigated. Over a 14 day period, MM6 cells were cultured in vitro and treated with 1μM and 10μM Rosiglitazone. Cell viability and proliferation were evaluated by Haemocytometer cell count and MTS assay respectively. Turbidity due to cell density was assessed spectrophotometrically. Apoptosis was determined by Caspase-Glo 3/7 assay. Expression of the endoplasmic reticulum (ER) stress-inducible protein sarco-endoplasmic reticulum Ca2+ATPase-2b (SERCA2b) was determined by Western blot. Neither 1μM nor 10μM Rosiglitazone exerted statistically significant inhibitory effects on cell proliferation, turbidity due to cell density, or cell viability (p > 0.05 in all cases). In contrast, Rosiglitazone induced increased apoptosis, but a significant difference was only observed in 10μM-treated cells compared with control cells (3.04 ± 0.52 control; p < 0.05) while 1μM-treated cells showed a non-significant increase (1.50 ± .06 control; p > 0.05). Meanwhile the expression of SERCA2b was up-regulated significantly in cells treated for >4hrs (e.g 2.45 ± 0.06 control at 24 hrs; p < 0.05) with 10μM Rosiglitazone. It was concluded that high doses (10μM) of Rosiglitazone up-regulate SERCA2b expression and induce apoptosis of MM6 cells by activating an ER stress response via a PPARγ-independent mechanism. The therapeutic relevance of these observations is a matter for further investigations. Key words: Rosiglitazone, PPARγ, Monocytes, ER Stress, SERCA2b, Apoptosi

Phase II study of two dose schedules of C.E.R.A. (Continuous Erythropoietin Receptor Activator) in anemic patients with advanced non-small cell lung cancer (NSCLC) receiving chemotherapy

BACKGROUND: C.E.R.A. (Continuous Erythropoietin Receptor Activator) is an innovative agent with unique erythropoietin receptor activity and prolonged half-life. This study evaluated C.E.R.A. once weekly (QW) or once every 3 weeks (Q3W) in patients with anemia and advanced non-small cell lung cancer (NSCLC) receiving chemotherapy. METHODS: In this Phase II, randomized, open-label, multicenter, dose-finding study, patients (n = 218) with Stage IIIB or IV NSCLC and hemoglobin (Hb) ≤ 11 g/dL were randomized to one of six treatment groups of C.E.R.A. administered subcutaneously for 12 weeks: 0.7, 1.4, or 2.1 μg/kg QW or 2.1, 4.2, or 6.3 μg/kg Q3W. Primary endpoint was average Hb level between baseline and end of initial treatment (defined as last Hb measurement before dose reduction or transfusion, or the value at week 13). Hematopoietic response (Hb increase ≥ 2 g/dL or achievement of Hb ≥ 12 g/dL with no blood transfusion in the previous 28 days determined in two consecutive measurements within a 10-day interval) was also measured. RESULTS: Dose-dependent Hb increases were observed, although the magnitude of increase was moderate. Hematopoietic response rate was also dose dependent, achieved by 51% and 62% of patients in the 4.2 and 6.3 μg/kg Q3W groups, and 63% of the 2.1 μg/kg QW group. In the Q3W group, the proportion of early responders (defined as ≥ 1 g/dL increase in Hb from baseline during the first 22 days) increased with increasing C.E.R.A. dose, reaching 41% with the highest dose. In the 6.3 μg/kg Q3W group, 15% of patients received blood transfusion. There was an inclination for higher mean Hb increases and lower transfusion use in the Q3W groups than in the QW groups. C.E.R.A. was generally well tolerated. CONCLUSION: C.E.R.A. administered QW or Q3W showed clinical activity and safety in patients with NSCLC. There were dose-dependent increases in Hb responses. C.E.R.A. appeared to be more effective when the same dose over time was given Q3W than QW, with a suggestion that C.E.R.A. 6.3 μg/kg Q3W provided best efficacy in this study. However, further dose-finding studies using higher doses are required to determine the optimal C.E.R.A. dose regimen in cancer patients receiving chemotherapy