Possible involvement of androgen receptor alterations in hepatocarcinogenesis.

BACKGROUND: Androgen receptors (ARs) act as transcription factors. An increased AR activity could be due either to mutations or to an increased expression of the receptor. AR mutations involving the hormone binding domain could increase AR function and promote carcinogenesis, as suggested for prostate cancer. AIMS: Herein, we evaluated qualitative (point mutations involving the hormone binding domain) and quantitative AR alterations and their possible correlation with cell proliferation and tumour grading. MATERIALS: Carcinomatous and non-cancerous surrounding liver tissue was collected from 14 Caucasian patients with hepatocarcinoma. They were all affected by cirrhosis with different aetiologies. METHODS: AR missense mutations, AR mRNA and protein levels, AR distribution in the liver, liver cell proliferation, and tumour staging were evaluated by DNA sequencing, quantitative real-time PCR, Western blot analysis, immunofluorescence, PCNA immunostaining, and conventional histological techniques, respectively. RESULTS: AR gene regions encoding the hormone binding domain did not contain any missense mutation. AR mRNA and protein levels were increased in hepatocarcinoma compared to non-cancerous surrounding tissue. Cell proliferation was significantly increased in the tumour compared to non-cancerous surrounding tissue. CONCLUSIONS: Mutations of the AR regions studied were not involved in hepatocarcinogenesis. Elevated AR levels in transformed cells could have a tumour promoting effect by stimulating cell growth.

FOLFIRI with or without celecoxib in advanced colorectal cancer: a randomized phase II study of the Gruppo Oncologico dell'Italia Meridionale (GOIM).

BACKGROUND: The aim of the study was to verify the efficacy and safety of the addition of celecoxib to FOLFIRI combination therapy in patients affected by advanced colorectal cancer. PATIENTS AND METHODS: Eighty-one chemotherapy-naïve patients entered in this randomized phase II trial of the GOIM (protocol no. 2301). Patients were randomized to receive FOLFIRI regimen (arm A): irinotecan 180 mg/m(2) on day 1 with LV5FU2 regimen (LV at 100 mg/m(2) administered as a 2-h infusion before FU at 400 mg/m(2) as an intravenous bolus injection, and FU at 600 mg/m(2) as a 22-h infusion immediately after 5-FU bolus injection on day 1 and 2); or FOLFIRI plus celecoxib 400 mg twice daily for 14 days (arm B). Both treatments were repeated every 2 weeks. RESULTS: Seventy-seven patients (38 in arm A and 39 in arm B) were evaluable for response. The overall response rate was 41% in arm A (95% CI 27% to 57%) and 35% in arm B (95% CI 20% to 50%). When only assessable patients were analyzed, overall response rate was 45% in arm A (95% CI 29% to 61%) and 36% in arm B (95% CI 21% to 51%). Median time to progression, median duration of response and survival were, respectively, 8 months, 9 months and 16 months in arm A, and 7 months, 9 months and 19 months in arm B. All patients were evaluable for toxicity, which was globally mild in both arms; grade 3-4 toxicity was uncommon, and gastrointestinal disturbances were the most common. CONCLUSIONS: FOLFIRI regimen is effective and well-tolerated as a first-line treatment in patients with advanced colorectal cancer. The addition of celecoxib to FOLFIRI regimen does not improve results.

The biophysical and pharmacological characteristics of skeletal muscle ATP-sensitive K+ channels are modified in K+-depleted rat, an animal model of hypokalemic periodic paralysis.

We evaluated the involvement of the sarcolemmal ATP-sensitive K+ channel in the depolarization of skeletal muscle fibers occurring in an animal model of human hypokalemic periodic paralysis, the K+-depleted rat. After 23-36 days of treatment with a K+-free diet, an hypokalemia was observed in the rats. No difference in the fasting insulinemia and glycemia was found between normokalemic and hypokalemic rats. The fibers of the hypokalemic rats were depolarized. In these fibers, the current of sarcolemmal ATP-sensitive K+ channels measured by the patch-clamp technique was abnormally reduced. Cromakalim, a K+ channel opener, enhanced the current and repolarized the fibers. At channel level, two open conductance states blocked by ATP and stimulated by cromakalim were found in the hypokalemic rats. The two states could be distinguished on the basis of their slope conductance and open probability and were never detected on muscle fibers of normokalemic rats. It is known that insulin in humans affected by hypokalemic periodic paralysis leads to fiber depolarization and provokes paralysis. We therefore examined the effects of insulin at macroscopic and single-channel level on hypokalemic rats. In normokalemic animals, insulin applied in vitro to the muscles induced a glybenclamide-sensitive hyperpolarization of the fibers and also stimulated the sarcolemmal ATP-sensitive K+ channels. In contrast, in hypokalemic rats, insulin caused a pronounced fiber depolarization and reduced the residual currents. Our data indicated that in hypokalemic rats, an abnormally low activity of ATP-sensitive K+ channel is responsible for the fiber depolarization that is aggravated by insulin.

Modulation of ATP-sensitive K+ channel by insulin in rat skeletal muscle fibers.

In the present study we evaluated the modulation of the sarcolemmal ATP sensitive K+ channel by insulin. The "in vivo" administration of insulin to the rats led to an hyperpolarization of the skeletal muscle fibers. This effect is antagonized by "in vitro" incubation of the muscle with glybenclamide, an ATP sensitive K+ channel blocker. Patch clamp experiments revealed that insulin enhanced the mean current of the ATP sensitive K+ channel by a factor of 1.4. This effect is mediated by an increase of the channel open probability, while no change occurred in the single channel conductance nor in the channel density. In the treated rats, the sensitivity of the channel to ATP and glybenclamide is abnormally reduced. Our results are consistent with an activation of the ATP sensitive K+ channel by insulin. This contributes to the hyperpolarization of the skeletal muscle fibers.