Testing anabolic activity, potency and mechanisms of action of the phyto-derived beta 2 agonist higenamine

Higenamine (Hige), a plant derived alkaloid is classified as β2 agonist by the World Anti-Doping Agency (WADA). However, pharmacologic mechanisms of its performance-enhancing activity have not been investigated so far. Therefore, we investigate the anabolic activity and associated molecular mechanisms of Hige in C2C12 myotubes. In differentiated C2C12 cells dose-dependent effects of Hige on myotube size were analyzed. The mRNA expression of genes involved in hypertrophy was measured. For mechanistic studies, β2-adrenoceptor (ADRB2), androgen receptor (AR), and estrogen receptor (ER) inhibitors and dexamethasone (Dexa) were co-incubated and myotube diameter was evaluated. The interaction of Hige with the AR and ER was investigated. Hige treatment significantly increased myotube diameters and stimulated the mRNA expression of hypertrophy-involved genes. In contrast to the ADRB2 inhibitor (ICI 118551), the ER inhibitor ZK 191703, the AR inhibitor Flutamide (Flu), and treatment with Dexa were able to antagonize the Hige-induced increase of myotube diameter. Hige has antagonistic activity in the AR and ER yeast transactivation assay. Our results demonstrate that Hige induces anabolic effects in C2C12 cells but not via the ADRB2. There are indications for a cross talk between Hige and the AR and ER. Future studies are necessary to investigate the involved molecular mechanisms.

Combinatory in vitro effects of the β2-agonists salbutamol and formoterol in skeletal muscle cells

β2-agonists are used for the treatment of bronchoconstriction, but also abused in doping. Beside an ergogenic activity β2-agonists may have also anabolic activity. Therefore, we investigated the anabolic activity and associated molecular mechanisms of Salbutamol (SAL) and Formoterol (FOR) alone, as well as in combination in C2C12 myotubes. In differentiated C2C12 cells, dose-dependent effects of SAL and FOR (alone/in combination) on myotube diameter, myosin heavy chain (MHC) protein expression and the mRNA expression of genes involved in hypertrophy were analyzed. β2-adrenoceptor 2 (ADRB2), androgen receptor (AR) and estrogen receptor (ER) inhibitors, as well as dexamethasone (Dexa) were co-incubated with the β2-agonists and myotube diameter was determined. SAL and FOR treatment significantly induced hypertrophy and increased MHC expression and the mRNA expression of Igf1, mTOR, PIk3r1 and AMpKa2. In contrast to an ER inhibitor, the ADRB2 and AR inhibitors, as well as Dexa antagonized FOR and SAL induced hypertrophy. Combined treatment with SAL and FOR resulted in significant additive effects on myotube diameter and MHC expression. Future clinical studies are needed to prove this effect in humans and to evaluate this finding with respect to antidoping regulations.

Survival with dacarbazine and fotemustine in newly diagnosed glioblastoma multiforme

A total of 55 patients with histologically proven glioblastoma multiforme (total gross resection: n=24, subtotal resection: n=20, stereotactic biopsy: n=11) were treated with the combination of dacarbazine (D) (200 mg m(-2)) and fotemustine (F) (100 mg m(-2)) and concomitant radiotherapy (2 Gy day(-1), 5 days per week using limited fields up to 60 Gy) to assess efficacy and toxicity of this regimen. Survival (median survival, 12-, 18- and 24-month survival rates) and time to progression (median time to progression (TTP), 6-month progression-free survival) were analysed by Kaplan-Meier's method. A total of 268 (range 1-8, median: 5) cycles were administered. Median survival is 14.5+ (range: 0.5-40+) months, and the 12-, 18- and 24-month survival rates are 58, 29 and 23%, respectively. Median TTP from the start of D/F therapy is 9.5+ (range: 0.5-33+) months. The 6-month progression-free survival is 54%. Partial remissions were observed in 3.6%. Main toxicity was thrombocytopenia. Five patients were excluded from further D/F application, four patients because of prolonged thrombocytopenia NCI-CTC grades 3 and 4 and one patient because of whole body erythrodermia. One patient died because of septic fever during thrombocytopenia and leukopenia NCI-CTC grade 4 after the first cycle. No other toxicities of NCI-CTC grade 3 or 4 occurred. The treatment is feasible in a complete outpatient setting and the results of the D/F regimen justify further investigations with these compounds.

[Multimodal therapy of high-grade gliomas in adults]

Multimodal Therapy of High Grade Gliomas in Adults For chemotherapy of high-grade gliomas only few substances with proven efficacy are available. Today, even the newest substances are not proven to be superior to nitrosoureas. Although nitrosoureas are still considered as commonly accepted standard treatment, these results are based on studies in which response evaluation was not performed according to standardized criteria: prognostic criteria were not taken into account and statistical power of these studies is limited. However, a lot of questions remain to be dealt with and are currently under investigation in multicentric randomized studies. Therefore, patients should be encouraged to participate in prospectively randomized trials. With or after chemotherapy, supportive and palliative care including neurorehabilitation are important to improve patients' quality of life.

Glutathione in the prevention of cisplatin induced toxicities. A prospectively randomized pilot trial in patients with head and neck cancer and non small cell lung cancer

PURPOSE

Glutathione has been shown to be an effective chemoprotector against cisplatin-induced side effects in patients with ovarian cancer. In view of this fact, we performed a randomized clinical pilot-trial in the management of other solid tumors in order to compare application of Glutathione to intensive hydration in patients undergoing chemotherapy with a regimen including cisplatin.

PATIENTS AND METHODS

Twenty patients suffering from advanced non small cell lung cancer (n = 6) or head- and neck cancer (n = 14) were enrolled in the study. All patients received 80 mg/m2 cisplatin along with etoposide or 5-fluorouracil every 4 weeks. Patients randomized to application of Glutathione (n = 11) received 5 g of Glutathione immediately before application of cisplatin followed by 2000 ml of normal saline. Patients in the control group (n = 9) received 2000 ml electrolyte infusion before and 2000 ml of normal saline with forced diuresis after cisplatin.

RESULTS

The intensity of hematologic toxicity was significantly less pronounced in patients treated with Glutathione than in the control group (hemoglobin: 10.7 vs 9.5 mg% respectively, p = 0.039; white blood cell count 3.3 vs 2.2 x 103/microliter respectively, p = 0.004; platelets 167 vs 95 x 103/microliter respectively, p = 0.02), whereas in terms of non-hematologic toxicity no difference was observed. Objective remission occurred in 6 out of 11 evaluable patients from the group receiving Glutathione (55%; complete remission: 9%; partial remission: 46%), and in 4 out of 8 evaluable patients from the control group (partial remission: 50%). However, there was no statistical difference in terms of response and overall survival (13.5 months vs. 10.5 months) between the two groups.

CONCLUSIONS

Application of Cisplatin and Glutathione seems to be safe and feasible and the antitumoral efficacy of cisplatin is apparently not impaired by the concomitant use of Glutathione in patients with solid tumors.