Aleksandra Stanczak

Prognostic significance of Wnt-1, β-catenin and E-cadherin expression in advanced colorectal carcinoma.

Wnt/β-catenin pathway plays an important role in initiation and progression of colorectal oncogenesis. The aim of this study was to determine expression and localization of E-cadherin, β-catenin and Wnt-1 proteins in colorectal tumors. Expression of β-catenin, E-cadherin and Wnt-1 was determined by immunohistochemistry on advanced colorectal cancers. Abnormal expression of E-cadherin, β-catenin, Wnt-1 was observed. Additionally, we revealed correlations between levels of studied proteins and histoclinical data. In multivariate analysis nuclear β-catenin, higher carcinoembryonic antigen serum level before treatment, female sex and tumor localized in colon or rectum were independent unfavorable prognostic factors. These findings support the hypothesis that Wnt/β-catenin pathway plays an important role in advanced colorectal carcinoma.

Wnt/β-catenin pathway as a potential prognostic and predictive marker in patients with advanced ovarian cancer.

Backgroundβ-catenin is the key protein in the WNT signalling pathway and it forms adherent junctions together with E-cadherin. In ovarian carcinoma, abnormal expression of β-catenin, E-cadherin and WNT-1 was observed, but their prognostic and predictive role is unclear. The aim of this study was to clarify the prognostic and predictive role of E-cadherin, β-catenin and WNT-1 in advanced epithelial ovarian carcinoma (AEOC).MethodsThe expression of E-cadherin, β-catenin and WNT-1 was determined by immunohistochemistry in AEOC. The correlation between expression of these proteins and progression-free survival (PFS) and overall survival (OS) was evaluated. Statistical analyses included Kaplan-Meier estimation, log-rank test, Spearman correlation and Cox proportional-hazards model.ResultsIn ovarian cancer, intense expression of E-cadherin, β-catenin and WNT-1 was found. In multivariate analysis, strong membrane β-catenin expression was an independent unfavourable predictor for PFS (HR 2.19, 95% CI 1.09-4.39; p = 0.028), while in univariate analysis, strong membrane β-catenin expression was a prognostic factor for OS in patients with AOC (p = 0.039). In multivariate analysis, only resistance to first-line chemotherapy was an adverse independent prognostic factor for OS (HR 16.84; 95% CI 5.07-55.98; p < 0.0001). Additionally, strong membranous β-catenin expression was associated with resistance to platinum-based chemotherapy (p = 0.027).ConclusionsThese findings support that WNT/β-catenin pathway and E-cadherin are important factors in advanced epithelial ovarian cancer.

Cell-based assay for low- and high-scale screening of the Wnt/β-catenin signaling modulators

Deregulation of the Wnt/β-catenin signaling pathway is associated with many serious disorders, including cancer and Alzheimers disease. The pivotal player is β-catenin, which avoids degradation after activation of the pathway and is translocated to the nucleus, where it interacts with TCF/LEF transcription factors and induces expression of genes involved in cell cycle and apoptosis regulation. The identification of small molecules that may affect Wnt/β-catenin signaling remains an important target during the development of novel therapies. We used the TCF/LEF lentiviral vector and the Wnt-independent H1703 cell line to develop a luciferase reporter-based cell assay for screening of the Wnt/β-catenin pathway modulators. Following the optimization of cell density, concentration of activator, and stimulation time, the reporter system was validated by demonstrating its specific and dose-dependent response to several established modulators of Wnt/β-catenin signaling such as Wnt3a, small interfering RNA (siRNA) against β-catenin, glycogen synthase kinase 3 (GSK-3), and β-catenin/TCF transcription complex inhibitors. Two pilot screens of inhibitors and activators of Wnt/β-catenin signaling identified potential novel modulators of this pathway. Our findings suggest that the H1703-7TFP assay constitutes a suitable model of low background and high sensitivity for the low- and high-scale screening of the Wnt/β-catenin pathway modulators.

Differences in gene expression and alterations in cell cycle of acute myeloid leukemia cell lines after treatment with JAK inhibitors

Janus kinase (JAK) inhibitors are a promising treatment strategy in several hematological malignancies and autoimmune diseases. A number of inhibitors are in clinical development, and two have already reached the market. Unfortunately, all of them are burdened with different toxicity profiles. To check if the JAK inhibitors of different selectivity evoke different responses on JAK2-dependent and independent cells, we have used three acute myeloid leukemia cell lines with confirmed JAK2 mutation status. We have found that JAK inhibitors exert distinct effect on the expression of BCLXL, CCND1 and c-MYC genes, regulated by JAK pathway, in JAK2 wild type cells in comparison to JAK2 V617F-positive cell lines. Moreover, cell cycle analysis showed that inhibitors alter the cycle by arresting cells in different phases. Our results suggest that observed effect of JAK2 inhibitors on transcription and cell cycle level in different cell lines are associated not with activity within JAK family, but presumably with other off-target activities.

Abstract B33: Prognostic role of Wnt/beta‐catenin pathway in colorectal carcinoma

Introduction: Beta‐catenin is a member of a cadherin‐catenin complex mediating cell adhesion. It is also a key protein of Wnt/Beta‐catenin pathway responsible for cell cycle and proliferation. This is important for initiation and progression of colorectal cancer. The aim of this study was to determine expression and localization of E‐cadherin, Beta‐catenin and Wnt‐1 proteins in colorectal tumors. Description: Forty‐four unrelated patients with advanced colorectal carcinoma (CRC) were enrolled consecutively from CRC patients attending palliative care. Expression of Beta‐catenin, E‐cadherin and Wnt‐1 was determined by immunohistochemistry on formalin‐fixed, paraffin‐embedded primary colorectal tissue. The expression was scored by two independent observers who had no knowledge of the clinical data. Correlation was measured with Spearman test, overall survival were analyzed with Kaplan‐Meier method. Log‐rank test was used for univariate analysis, while Cox regression model for multivariate analysis. A value of p Results: Decreased expression of membrane E‐cadherin and Beta‐catenin was observed in 34% and 27% of patients, respectively. Abnormal cytoplasmic E‐cadherin was detected in 32% of cases and abnormal cytoplasmic and nuclear Beta‐catenin was detected in 50% and 25% of patients, respectively. 60% of patients had decreased cytoplasmic Wnt‐1 expression. Correlation was seen between cytoplasmic E‐cadherin and cytoplasmic Beta‐catenin (R 0,35; p=0,019). Nuclear localization of Betacatenin was correlated with localization of primary tumor (the highest expression in rectum) (R 0,48; p=0,001) and tumor size (R 0,32; p=0,035). Lower Wnt‐1 expression was correlated with higher nodal stage (R ‐0,31; p=0,047). Nuclear Beta‐catenin was an adverse prognostic factor in univariate analysis (log‐rank test p=0,034) which was confirmed in multivariate analysis (HR 4,27 95% CI 1,70–10,72; p=0,002). Higher CEA serum level before treatment (HR 4,30 95% CI 1,35–13,66; p=0,013) and female sex (HR 2,75 95% CI 1,24–6,10; p=0,013) were also independent prognostic factors. Conclusions: This finding supports that Beta‐catenin is an independent prognostic factor for colorectal carcinoma. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B33.