Role of Kupffer cells in thioacetamide-induced cell cycle dysfunction

It is well known that gadolinium chloride (GD) attenuates drug-induced hepatotoxicity by selectively inactivating Kupffer cells. In the present study the effect of GD in reference to cell cycle and postnecrotic liver regeneration induced by thioacetamide (TA) in rats was studied. Two months male rats, intraveously pretreated with a single dose of GD (0.1 mmol/Kg), were intraperitoneally injected with TA (6.6 mmol/Kg). Samples of blood and liver were obtained from rats at 0, 12, 24, 48, 72 and 96 h following TA intoxication. Parameters related to liver damage were determined in blood. In order to evaluate the mechanisms involved in the post-necrotic regenerative state, the levels of cyclin D and cyclin E as well as protein p27 and Proliferating Cell Nuclear Antigen (PCNA) were determined in liver extracts because of their roles in the control of cell cycle check-points. The results showed that GD significantly reduced the extent of necrosis. Noticeable changes were detected in the levels of cyclin D1, cyclin E, p27 and PCNA when compared to those induced by thioacetamide. Thus GD pre-treatment reduced TA-induced liver injury and accelerated the postnecrotic liver regeneration. These results demonstrate that Kupffer cells are involved in TA-induced liver and also in the postnecrotic proliferative liver states.

[Biomarkers in breast cancer]

Biomarkers are measured in the management of breast cancer patients for the following purposes. (1) Early detection of breast cancer: blood tumor markers such as CA 15-3 are useless for this detection because of a low sensitivity. Proteomics profiling has recently been investigated using blood or nipple aspirate fluid for the detection. Measurement of CEA and HER 2 in abnormal nipple discharge has been approved for diagnosis of breast cancer in Japan. (2) Monitoring of breast cancer patients: serum tumor markers are routinely measured for early detection of recurrent diseases, evaluation of therapeutic response and monitoring outcome of patients by a majority of breast cancer experts in Japan. Study results investigated by the Study Group of the Japanese Breast Cancer Society in 2001 are presented with regard to the questionnaire survey on the present status of tumor marker measurement and the clinical study on usefulness of tumor markers for the evaluation for therapeutic response. (3) Prognostic factors: new biomarkers have been investigated to select patients at high risk for distant metastases, which could not be selected by classic prognostic factors. Three prognostic factors (UPA/PAI-1, cyclin E, gene profiling), which were discussed at the 8th St. Gallen International Consensus Meeting last year, are mainly discussed. (4) Predictive factors for therapeutic response: hormone receptors (HR) have been used as reliable predictive factors for response to endocrine therapy. Other biomarkers have been investigated to select patients with tumors HR-positive but unresponsive to endocrine therapy. Current status, clinical significance, problems and future directions on predictive factors for response to cytotoxic chemotherapy are also discussed.

New data on chemotherapy in the adjuvant setting

In the last few months, there have been three sets of new, provocative data that might have important implications for the daily prescription of adjuvant chemotherapy (CT) in the future. (1) Urokinase-type plasminogen activator (UPA) and type 1 plasminogen activator inhibitor (PAI-1), two molecular markers of invasion already known for their powerful prognostic value in node-negative breast cancer, seem to predict for enhanced benefit from adjuvant CT, while the benefit from adjuvant endocrine therapy seems independent of them. The predictive value of these markers, however, remains suboptimal and an important limitation lies in their evaluation through a cytosolic assay, which is compromised for small tumours (<1cm). (2) Breast cancer 'gene expression profiles' have been identified through DNA-microarray technology and seem to be better predictors of clinical outcome in young women (less than 55 years old) with stage I or II breast cancer, when compared to the currently used clinical-pathological criteria. Remarkably, these molecular data suggest that the prognostic profile of breast cancer does not depend on lymph node status and that it is possible to identify a group of node-positive breast cancer patients with an unexpectedly good prognosis. Prospective and independent confirmation is needed, but these data are fascinating and carry the hope that CT decision-making in breast cancer will be greatly facilitated in the future. (3) The recently reported CALGB 9741 (or INT 69741) trial shakes our belief that 'one cycle of CT every 3 weeks' is the adequate adjuvant treatment for node-positive breast cancer. Launched in 1999, it aimed to test two novel concepts based on mathematical models of tumour cell growth kinetics. Concept 1 implies that dose-densification of CT, i.e., delivering drugs at reduced intervals, will maximize the chances of eradicating the tumour; and concept 2 extends the first one to encompass situations of heterogeneous drug sensitivity through the use of sequential dose-dense, non-cross-resistant single agents or regimens. The 3-year results of this trial strongly support concept 1; a longer follow-up and a confirmation study are desirable before recommending changes in routine patient care.

Decreasing of p27(Kip1)and cyclin E protein levels is associated with progression from superficial into invasive bladder cancer

The p27(Kip1)(p27) protein is a cyclin-dependent kinase inhibitor of the transition from G1 to S phase. It has been reported that decreased p27 protein level is a negative prognostic indicator in human tumours including bladder cancer. We studied the relationship between protein levels of p27, cyclin E and Ki-67 and clinicopathological features of 145 consecutive Japanese patients with transitional cell carcinoma of the bladder using immunohistochemical staining. Low protein levels of p27 were associated with low staining of cyclin E (P = 0.0302), high Ki-67 index (P = 0.0306), poorly differentiated grade (P = 0.0006), muscle invasion (P = 0.0019) and lymph node metastsis (P = 0.0002). Low staining of cyclin E and high Ki-67 index correlated with poorly differentiated grade, muscle invasion and lymph node metastsis. Cyclin E protein levels was inversely related with Ki-67 index (P = 0.0002). Kaplan-Meier plots of survival rate in patients with low versus high p27 staining showed that low protein levels of p27 were associated with a shortened disease-free and overall survival (P< 0.0001 and P< 0.0001, respectively). Similarly, low staining of cyclin E and high Ki-67 index correlated with a shortened disease-free and overall survival. On multivariate analysis using Cox proportional hazards model, low protein levels of p27 and high Ki-67 index were independent predictors of shortened disease-free (P< 0.0001, P = 0.0031, respectively), and low protein levels of p27, low staining of cyclin E and high Ki-67 index of overall survival (P = 0.0017, P = 0.0009, P = 0.0003, respectively). In superficial bladder tumours (Ta, T1; 86 patients), significant correlations were observed between low p27 staining and high Ki-67 index and early recurrence (P = 0.0048, P = 0.0178, respectively). Among the recurrenced superficial tumours (35 patients), the tumours which remained at a low stage showed high protein levels of p27 and cyclin E, and the tumours which progressed to invasive disease showed a gradual decrease in p27 and cyclin E protein levels over time. Our findings suggest that decreased protein levels of p27 and cyclin E play a role in the progression of bladder cancer and to evaluate these protein levels may be useful in management of the diseases.