The tumor suppressor PTEN positively regulates macroautophagy by inhibiting the phosphatidylinositol 3-kinase/protein kinase B pathway

The tumor suppressor PTEN is a dual protein and phosphoinositide phosphatase that negatively controls the phosphatidylinositol (PI) 3-kinase/protein kinase B (Akt/PKB) signaling pathway. Interleukin-13 via the activation of the class I PI 3-kinase has been shown to inhibit the macroautophagic pathway in the human colon cancer HT-29 cells. Here we demonstrate that the wild-type PTEN is expressed in this cell line. Its overexpression directed by an inducible promoter counteracts the interleukin-13 down-regulation of macroautophagy. This effect was dependent upon the phosphoinositide phosphatase activity of PTEN as determined by using the mutant G129E, which has only protein phosphatase activity. The role of Akt/PKB in the signaling control of interleukin-13-dependent macroautophagy was investigated by expressing a constitutively active form of the kinase ((Myr)PKB). Under these conditions a dramatic inhibition of macroautophagy was observed. By contrast a high rate of autophagy was observed in cells expressing a dominant negative form of PKB. These data demonstrate that the signaling control of macroautophagy overlaps with the well known PI 3-kinase/PKB survival pathway and that the loss of PTEN function in cancer cells inhibits a major catabolic pathway.

Autophagy delays sulindac sulfide-induced apoptosis in the human intestinal colon cancer cell line HT-29

Autophagy is a major catabolic process allowing the renewal of intracellular organelles by which cells maintain their homeostasis. We have previously shown that autophagy is controlled by two transduction pathways mediated by a heterotrimeric Gi3 protein and phosphatidylinositol 3-kinase activities in the human colon cancer cell line HT-29. Here, we show that 3-methyladenine, an inhibitor of autophagy, increases the sensitivity of HT-29 cells to apoptosis induced by sulindac sulfide, a nonsteroidal anti-inflammatory drug which inhibits the cyclooxygenases. Similarly, HT-29 cells overexpressing a GTPase-deficient mutant of the G(alpha i3) protein (Q204L), which have a low rate of autophagy, were more sensitive to sulindac sulfide-induced apoptosis than parental HT-29 cells. In both cell populations we did not observe differences in the expression patterns of COX-2, Bcl-2, Bcl(XL), Bax, and Akt/PKB activity. However, the rate of cytochrome c release was higher in Q204L-overexpressing cells than in HT-29 cells. These results suggest that autophagy could retard apoptosis in colon cancer cells by sequestering mitochondrial death-promoting factors such as cytochrome c.

Exploring the dose-response relationship between alcohol consumption and the risk of several alcohol-related conditions: a meta-analysis

OBJECTIVE

To compare the strength of the evidence provided by the epidemiological literature on the association between alcohol consumption and the risk of six cancers (oral cavity, oesophagus, colorectum, liver, larynx, breast), hypertension, cerebrovascular diseases, gastric and duodenal ulcer, liver cirrhosis and other chronic liver diseases, pancreatitis and injures and adverse effects.

METHODS

A search of the epidemiological literature from 1966 to 1998 was performed by several bibliographic databases. Meta-regression models were fitted considering fixed and random models and linear and non-linear effects of alcohol intake on the risk of each condition. The effects of some characteristics of the studies including an index of their quality were considered as putative sources of heterogeneity of the estimates. Publication bias was also investigated by asymmetry of funnel plots.

RESULTS

Of the 397 initially reviewed studies, 200 were selected for meta-analysis. Since qualitative characteristics of the studies were often significant sources of heterogeneity among them, the estimates of the pooled dose-response slopes were based only on the 123 studies with higher quality score and/or reporting adjusted estimates of relative risks. Higher alcohol-related risks were found for liver cirrhosis, neoplasms of the upper respiratory and digestive tracts, haemorrhagic stroke and injuries and adverse effects. Weaker but significant associations were found for colorectum, liver and breast cancers, essential hypertension and chronic pancreatitis. For all these conditions, low intakes, corresponding to daily consumption of two drinks or two glasses of wine (25 g/day), have shown significant risks. Ischaemic stroke and gastric and duodenal ulcer seem independent of alcohol intake. The area in which the study was performed, the study's design and the outcome variable differently affected the slopes.

CONCLUSIONS

The small number of sufficiently reliable studies, the strong indications of heterogeneity across them and the suspicion of publication bias suggest that there is a great need for well-conducted epidemiological studies performed in several countries, to examine the dose-response relationship between alcohol intake and the risk of several alcohol-related conditions, as well as the role of drinking pattern in determining the risk.

The measure of life-time alcohol consumption in patients with cirrhosis: reproducibility and clinical relevance

Our aims were to design a reproducible method of measuring life-time alcohol consumption in patients with cirrhosis, and to assess the risk of liver decompensation associated with alcohol intake using a case-control design and a multivariate analysis. We studied 439 patients ("cases") with decompensated cirrhosis, and 233 with compensated cirrhosis ("controls"). Mean life-time daily amount and duration of alcohol intake were measured by a standardized questionnaire, whose reproducibility, assessed by interviewing 75 relatives, was 70% for daily alcohol intake and 84% for duration of intake. Better reproducibility was found by re-interviewing patients at discharge from hospital. Daily alcohol intake was significantly higher in males, younger patients and patients with liver decompensation. After stratification according to the average life-time daily alcohol intake, we found a significant increase in the risk of liver decompensation from 125 g ethanol intake per day onwards. No association was found between duration of alcohol intake and risk of liver decompensation. We conclude that alcohol intake can be reliably and reproducibly measured: in patients with cirrhosis, increased alcohol intake is associated with increased risk of liver decompensation, with a significant dose-effect above a daily intake of 125 g ethanol.

Family compliance to a treatment programme for alcoholics: a prospective study of prognostic factors

A total of 198 alcoholic subjects was recruited into a treatment programme according to Hudolin's method. The programme included three steps: (1) presentation of the programme to the alcoholic family (four meetings); (2) a therapeutic community that met weekly over 4 months; and (3) attendance at an on-Treatment Alcoholic Club located close to the family's home residence (weekly self-conducted meetings). Data on the families' compliance to the treatment programme were obtained in January 1993 and the prognostic significance of 11 variables collected during the first step was determined by the proportional hazards regression model. The cumulative proportion of family compliance after 40 months was 36.4%, with similar drop-out rates at each of the three steps of the programme. The prognostic factor which was the major determinant of family compliance to treatment was the active presence of the whole family in the first step, while a good job performance was independently associated with family compliance, being a significant prognostic factor in the second step of the programme. Alcohol abstinence was obtained in 35.9% of the whole study group. This programme provided results for alcohol abstinence which are comparable with methods that require more expensive resources.

Amount and duration of alcohol intake in patients with chronic liver disease: an Italian multicentre study. AISF Group for the Study of Alcohol and Liver Disease

We report the results of an Italian multicenter study aimed at measuring retrospectively the lifetime amount and duration of alcohol consumption in non-selected consecutive patients with chronic liver disease. We used a standardized, reproducible questionnaire for measuring the lifetime daily alcohol intake (globally and separately for wine, beer and spirits), total alcohol intake and duration of alcohol consumption in 1,258 patients recruited from 17 medical centers. Wine intake contributed to the total alcohol intake in a proportion ranging from 44% to 85% throughout the centers. Spirits and beer intake contributed in smaller proportions (15% to 56%; and 3% to 27%, respectively). Males showed higher alcohol intake: those from northern-central Italy showed significantly higher intake than their southern-insular counterparts; of these, younger patients also showed a higher alcohol intake, due to a higher beer and spirit intake. Older patients showed higher intakes in southern-insular Italy, whereas the opposite was found in northern-central Italy. In this area, a longer duration of alcohol consumption was found, reflecting an earlier start in the use of alcohol. In conclusion, we believe that measuring alcohol intake on a wide series of patients in a multicenter study is feasible. This should stimulate gastroenterologists to approach the relationship between alcohol and liver disease using standardized and epidemiologically correct methods, and form the basis for well-designed case-control studies on a large scale, aimed at clarifying the risk of both hepatic and extrahepatic diseases associated with alcohol intake.

Alcohol consumption and non-cirrhotic chronic hepatitis: a case-control study

We carried out a hospital-based case-control study to assess the association of both the daily amount and the duration of alcohol intake with the risk of developing non-cirrhotic chronic liver disease (chronic hepatitis) in 121 chronic hepatitis patients diagnosed by laparoscopy and liver biopsy, and in 242 matched 'controls' randomly selected from inpatients of the same hospital. Alcohol intake was quantified in all subjects using a standardized questionnaire administered by two doctors unaware of the aim of the study. The odds ratio (OR) for chronic hepatitis was estimated by conditional logistic regression and increased exponentially from 1.0 for non-drinkers to 11.4 for daily alcohol intake of 325 g or more. Considering duration of alcohol consumption from up to 10 to up to 30 years, the ORs for chronic hepatitis consistently decreased for the daily alcohol intake categories of 25-50 g (from 74.1 to 0.7 respectively), 75-100 g (from 149.7 to 0.7 respectively) and 125 g or more (from 212.0 to 1.8 respectively). Our results suggest the existence of a dose-dependent individual susceptibility to the damaging effect of alcohol on the liver.

Clinical significance of antibody to the hepatitis delta virus in symptomless HBsAg carriers

Antibody to the hepatitis delta virus (anti-delta) was detected in 112 out of 2487 (5%) individuals fortuitously found to have the hepatitis B surface antigen (HBsAg) in the blood. Liver function was impaired in 38% (43 of 112) of the anti-delta-positive carriers but in only 9% (215 of 2375) of the anti-delta-negative subjects (p less than 0.001). Liver biopsy specimens were obtained from 31 antibody-positive and 97 antibody-negative subjects with impaired liver function. Important histological changes were observed in 61% of the 31 antibody-positive carriers (7 chronic active hepatitis, 4 active cirrhosis, 8 inactive cirrhosis) but in only 19% of the 97 antibody-negative carriers (p less than 0.001). The presence of anti-delta in serum identifies a subpopulation of apparently healthy HBsAg carriers whose risk of underlying liver disease is four times higher than that in the ordinary carrier. The identification of anti-delta in a symptom-free HBsAg carrier with abnormal liver function is thus an indication for a diagnostic liver biopsy.

Long-term results of surgical treatment for alkaline reflux gastritis in gastrectomized patients

Sixteen gastrectomized patients underwent surgical treatment for alkaline reflux gastritis by means of a Roux-en-Y loop duodenal diversion. Long-term evaluation of results was performed 5-9 years later. Ten patients (62.5%) showed good results, with absence of digestive symptoms and with an increase in body weight. Two patients (12.5%) had moderate results, with presence of sporadic and mild epigastric pain. Four patients (25%) had unsatisfactory results, with persistence of epigastric pain and absence of body weight increase. No patient had recurrent biliary vomiting or endoscopic evidence of endogastric biliary reflux. Among the six patients with moderate and unsatisfactory results, two had a significant alcoholic intake, two showed a high degree of anxiety on psychological assessment, and two had both factors. Alcoholism and psychological disturbances should be considered exclusion criteria when evaluating a gastrectomized patient for surgical cure of alkaline reflux gastritis.

An ultrastructural and immunohistochemical study on the delta antigen associated with the hepatitis B virus

Thirteen liver biopsies in which the delta antigen was detected by immunofluorescence were studied by electron microscopy and immune electron microscopy with peroxidase labelled IgG and F(ab1)2 fraction obtained from a human antiserum containing high-titre anti-delta antibodies. The findings were compared with those obtained in 11 HBcAg positive and in two HBsAg negative controls. Neither unique particulate morphology nor any HB virus ultrastructural component were visualised in the delta positive specimens; 20-23 nm naked core particles were observed in 10 of 11 biopsies displaying the HBcAg in immunofluorescence. Delta positive nuclei frequently contained dense round structures of diameter varying between 20 and 30 nm with a soft indistinct edge. These granules did not exhibit characteristic ultrastructural features which enabled them to be distinguished from other granular material observed occasionally in nuclei of normal and diseased livers. However, their association with the delta antigen has been proved by the deposition on identical structures of peroxidase labelled anti-delta antibody. These results suggest that the delta antigen is unrelated to the Dane particle, the putative HB virus. The granules observed in the delta positive nuclei are composed of an amorphous matrix, possibly insoluble aggregates of the delta antigen.