Etoposide-mediated glioblastoma cell death: dependent or independent on the expression of its target, topoisomerase II alpha?

BACKGROUND: Treatments which significantly improve progression-free and overall survival for patients with relapsed glioblastoma (GBM) after the standard therapy are lacking. The Topoisomerase II (TopoII) enzyme is a key target of anticancer agents because of the important role it plays in transcription regulation and chromatin remodeling. A drug with strong topoisomerase-mediated anticancer activity is etoposide that is used in combination with carboplatin in patients with relapsed GBM. We hypothesized that tumors harboring high expression of TopoII alpha (TopoIIa) would be more sensitive to etoposide treatment. METHODS: The relative expression levels of TopoIIa protein were measured in a panel of GBM cell lines using Western blot analysis and in a cohort of GBM using immunohistochemistry. Expression levels of TopoIIa in the cell lines were correlated with relative sensitivity to treatment with etoposide. To ascertain the role TopoIIa plays in mediating response to etoposide, expression was reduced with a siRNA targeted to TopoIIa. RESULTS: Protein expression of TopoIIa, although high in the cell lines, was very low in patient specimens. Correlations between TopoIIa protein expression and sensitivity to etoposide were evident. The IC(50) for the low-TopoIIa-expressing cell line, T98G, was almost 50 times higher than M059K (high TopoIIa). Inhibition of TopoIIa in MO59K cells with siRNA significantly altered the IC(50), increasing the resistance to etoposide. Interestingly, the expression of TopoIIa was not decreased after treatment with etoposide, indicating other mechanisms underplay treatment response. CONCLUSIONS: In vitro, the levels of TopoIIa protein expression correlate with response to etoposide but also multiple molecular events namely DNA-PK and MDR also play a role in cell sensitivity to etoposide. That we did not find a high expression of TopoIIa in clinical specimens further suggests the mechanisms underlying treatment response are complex.

Clinical impact and biomaterial evaluation of autologous platelet gel in cardiac surgery.

We compared the clinical efficacy of autologous platelet gel (APG) and gelatine (CONT), including biomaterial evaluation. In a prospective, randomized, controlled trial, 64 patients undergoing complex coronary artery bypass graft (CABG) surgery and/or aortic surgery, in whom the surgeon was able to identify a bleeding site for which conventional means to stop bleeding were impractical or proved unsuccessful, were enrolled. Aortic punch biopsy from each patient was harvested in explant cell (EC) culture media. Hemostasis success for the "oozing" category was 89% in APG and 60% in CONT (p< 0.05). For the "heavy bleeding" category, the success rates were 92% in APG and 45% in CONT (p<0.01). Contact of gelatine inhibited EC proliferation and APG increased cell cycling and EC quantity. Phagocytic capacity (PC) was significantly higher in the APG group (p<0.001). APG was significantly better than CONT with respect to hemostatic success rate, effects on wound healing and increased resistance to infection (PC).

In vivo effects of Urtica urens (dwarf nettle) on the expression of CYP1A in control and 3-methylcholanthrene-exposed rats.

The in vivo effects of the intraperitoneal administration of an Urtica urens L. (dwarf nettle) seed extract were examined on the hepatic, pulmonary, and renal cytochrome P450-dependent monooxygenase activities of rats co-administered with 3-methylcholanthrene (MC). Urtica extract was administered by intraperitoneal injection to male Wistar rats at 200 mgkg(-1)day(-1) for 4 days from which were also co-administered with intraperitoneal injection of 50mg of MC kg(-1) of body weight twice on days 1 and 3. MC treatment increased the 7-ethoxyresorufin O-deethylase (EROD) activity of the liver, lung, and kidney 54-, 21-, and 119-fold, respectively. Urtica treatment substantially reduced the 3MC induction of hepatic, lung, and renal EROD activity by 79, 42, and 50%, respectively. Similarly, compared with the control, MROD activities in liver and kidney were increased after MC administration, and these increases were significantly inhibited by Urtica. reverse transcriptase-polymerase chain reaction (RT-PCR) analysis clearly showed that the hepatic CYP1A1 and CYP1A2 mRNA levels substantially increased after treatment with MC, which was suppressed by Urtica supplementation. Western blotting studies also supported the alterations observed in the catalytic activities and mRNA levels. In conclusion, substantial reduction in CYP1A1 and CYP1A2 expression levels and related activities with Urtica are possibly associated with a potential chemoprotective ability of the Urtica due to the anticipated decrease in the activation of environmental chemical carcinogens through modulation of the CYP1A enzymes.

Effect of BCG vaccine on tuberculin skin tests in 7-11-year-old children.

AIM: To determine the effect of Bacillus Calmette Guerin (BCG) vaccination on tuberculin skin test responses in 7-11-year-old children, and also to clarify whether the number of vaccinations and the time interval between vaccination and tuberculin skin test have an effect on the test responses. METHOD: 1200 primary school children were evaluated for the presence and number of BCG scars. They were then given 5 TU PPD-S intra-dermally. Seventy-two hours after the application of tests, PPD indurations were measured. RESULTS: Mean indurations were 3.7 +/- 3.9, 6.5 +/- 5.4 and 9.2 +/- 7.1 mm in children with no scar, one scar and two scars, respectively. No statistical difference was found between mean induration of children with one scar and those with two scars. CONCLUSION: The effect of the number of BCG vaccinations and the time interval between vaccination and tuberculin skin test application on tuberculin skin test responses was statistically insignificant.