Involvement of Fas receptor and not tumor necrosis factor-Α receptor in ultraviolet-induced activation of acid sphingomyelinase

Fas receptor and tumor necrosis factor receptor-1 (TNFR1) mediate the activation of acid sphingomyelinase (ASMase), which catalyzes the hydrolysis of sphingomyelin to ceramide. Ceramide acts as a second messenger in mediating cell growth, differentiation, stress response, and apoptosis. Ultraviolet (UV) irradiation induces Fas receptor and TNFR1 aggregation. However, the roles of Fas receptor and TNFR1 in mediating UV-induced ASMase activation have not been explored. In this report, we demonstrate that Fas receptor, not TNFR1, mediated UV-induced activation of ASMase. Our data indicate that ASMase activity was not induced with UV irradiation but by TNFΑ in MCF-7 cells that expressed low levels of Fas receptor. In contrast, ASMase was activated by UV irradiation or TNFΑ treatment in Fas stably transfected MCF-7 cells. Immunofluorescence staining of TNFR1 on MCF-7 cells showed that TNFR1 was aggregated after treatment with UV irradiation or TNFΑ. However, UV-induced aggregation of TNFR1 did not lead to induction of ASMase activity. These results suggest that Fas receptor aggregation is solely responsible for UV-induced activation of ASMase. Further, with the use of BJAB and dominant-negative Fas-associated death domain–containing protein (FADD) stably transfected BJAB cells, we demonstrated that dominant-negative FADD partly inhibited UV-induced ASMase activation. Our results suggest that FADD is involved in UV-induced and Fas-mediated signaling pathways for activation of ASMase. Mol. Carcinog. 30:47–55, 2001. © 2001 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35061/1/1012_ftp.pd

Wnt signaling in triple negative breast cancer is associated with metastasis

Background Triple Negative subset of (TN) Breast Cancers (BC), a close associate of the basal-like subtype (with limited discordance) is an aggressive form of the disease which convey unpredictable, and poor prognosis due to limited treatment options and lack of proven effective targeted therapies. Methods We conducted an expression study of 240 formalin-fixed, paraffin-embedded (FFPE) primary biopsies from two cohorts, including 130 TN tumors, to identify molecular mechanisms of TN disease. Results The annotation of differentially expressed genes in TN tumors contained an overrepresentation of canonical Wnt signaling components in our cohort and others. These observations were supported by upregulation of experimentally induced oncogenic Wnt/β-catenin genes in TN tumors, recapitulated using targets induced by Wnt3A. A functional blockade of Wnt/β-catenin pathway by either a pharmacological Wnt-antagonist, WntC59, sulidac sulfide, or β-catenin (functional read out of Wnt/β-catenin pathway) SiRNA mediated genetic manipulation demonstrated that a functional perturbation of the pathway is causal to the metastasis- associated phenotypes including fibronectin-directed migration, F-actin organization, and invasion in TNBC cells. A classifier, trained on microarray data from β-catenin transfected mammary cells, identified a disproportionate number of TNBC breast tumors as compared to other breast cancer subtypes in a meta-analysis of 11 studies and 1,878 breast cancer patients, including the two cohorts published here. Patients identified by the Wnt/β-catenin classifier had a greater risk of lung and brain, but not bone metastases. Conclusion These data implicate transcriptional Wnt signaling as a hallmark of TNBC disease associated with specific metastatic pathways

The expression of the ubiquitin ligase subunit Cks1 in human breast cancer

INTRODUCTION: Loss of the cell-cycle inhibitory protein p27(Kip1 )is associated with a poor prognosis in breast cancer. The decrease in the levels of this protein is the result of increased proteasome-dependent degradation, mediated and rate-limited by its specific ubiquitin ligase subunits S-phase kinase protein 2 (Skp2) and cyclin-dependent kinase subunit 1 (Cks1). Skp2 was recently found to be overexpressed in breast cancers, but the role of Cks1 in these cancers is unknown. The present study was undertaken to examine the role of Cks1 expression in breast cancer and its relation to p27(Kip1 )and Skp2 expression and to tumor aggressiveness. METHODS: The expressions of Cks1, Skp2, and p27(Kip1 )were examined immunohistochemically on formalin-fixed, paraffin-wax-embedded tissue sections from 50 patients with breast cancer and by immunoblot analysis on breast cancer cell lines. The relation between Cks1 levels and patients' clinical and histological parameters were examined by Cox regression and the Kaplan–Meier method. RESULTS: The expression of Cks1 was strongly associated with Skp2 expression (r = 0.477; P = 0.001) and inversely with p27(Kip1 )(r = -0.726; P < 0.0001). Overexpression of Cks1 was associated with loss of tumor differentiation, young age, lack of expression of estrogen receptors and of progesterone receptors, and decreased disease-free (P = 0.0007) and overall (P = 0.041) survival. In addition, Cks1 and Skp2 expression were increased by estradiol in estrogen-dependent cell lines but were down-regulated by tamoxifen. CONCLUSION: These results suggest that Cks1 is involved in p27(Kip1 )down-regulation and may have an important role in the development of aggressive tumor behavior in breast cancer

Bcl-2 protein expression is associated with p27 and p53 protein expressions and MIB-1 counts in breast cancer

BACKGROUND: Recent experimental studies have shown that Bcl-2, which has been established as a key player in the control of apoptosis, plays a role in regulating the cell cycle and proliferation. The aim of this study was to investigate the relationship between Bcl-2 and p27 protein expression, p53 protein expression and the proliferation activity as defined by the MIB-1 counts. The prognostic implication of Bcl-2 protein expression in relation to p27 and p53 protein expressions and MIB-1 counts for breast cancer was also evaluated. METHODS: The immunohistochemical expression of Bcl-2 protein was evaluated in a series of 249 invasive ductal carcinomas of the breast, in which p27 and p53 protein expressions and MIB-1 counts had been determined previously. RESULTS: The Bcl-2 protein expression was found to be decreased in 105 (42%) cases. A decreased Bcl-2 protein expression was significantly correlated with a nuclear grade of III, a negative estrogen receptor, a decreased p27 protein expression, a positive p53 protein expression, positive MIB-1 counts and a positive HER2 protein expression. The incidence of a nuclear grade of III and positive MIB-1 counts increased as the number of abnormal findings of Bcl-2, p27 and p53 protein expressions increased. A univariate analysis indicated a decreased Bcl-2 protein expression to be significantly (p = 0.0089) associated with a worse disease free survival (DFS), while a multivariate analysis indicated the lymph node status and MIB-1 counts to be independently significant prognostic factors for the DFS. CONCLUSION: The Bcl-2 protein expression has a close correlation with p27 and p53 protein expressions and the proliferation activity determined by MIB-1 counts in invasive ductal carcinoma of the breast. The prognostic value of Bcl-2 as well as p27 and p53 protein expressions was dependent on the proliferation activity in breast cancer

A Study to investigate the role of p27 and Cyclin E immunoexpression as a prognostic factor in early breast carcinoma

<p>Abstract</p> <p>Background</p> <p>Cyclin E and p27 expression is easy to assess in human tissues by standard immunohistochemical techniques. Immunohistochemistry is cost effective, relatively easy to perform and will play more of a role in the future management of cancer. The aim of this study was to investigate the role of p27 and cyclin E immunoexpression as a prognostic factor in early breast carcinoma.</p> <p>Methods</p> <p>Cyclin E and p27 immunohistochemistry was performed on sixty six cases of breast carcinoma submitted over a five year period to the Division of Anatomical Pathology, Groote Schuur hospital; Whittaker and Associates; and PathCare. All tumours included in this study were less than 5 cm in diameter (pT1 and pT2 stage) and all the patients had wide local excisions performed. Follow up information was obtained from patient folders in the Department of Radiation Oncology.</p> <p>Results</p> <p>There was no significant association of cyclin E and p27 expression with distant metastasis free survival (MFS) for all invasive carcinomas in contrast to grade, lymph node spread and vascular invasion. However, there was a statistically significant direct association of cyclin E with distant metastases in all invasive carcinomas, in the subgroup of infiltrating duct carcinomas (IDC) and in the node negative group when cyclin E was stratified as negative and positive (low/high). In this study of early breast carcinoma, only 9/66 cases showed cyclin E expression. Of these, four patients had distant metastases, one patient had a local recurrence and four patients were alive at last follow-up. Furthermore, cyclin E expression was significantly associated with grade, lymph node spread, oestrogen receptor status and histological type. None of the lobular carcinomas showed cyclin E positivity and only one case of lobular carcinoma presented with distant metastases.</p> <p>59/66 cases were positive (low/high) for p27 while seven cases were negative, 22 cases showed low expression and 37 cases demonstrated high p27 expression.</p> <p>p27 was significantly associated with oestrogen receptor status only for all invasive carcinomas and in the IDC group. There was no statistical relationship between p27 and cyclin E, but 50 (76%) tumours with positive p27 expression were negative for cyclin E. There were similar results for the invasive ductal carcinoma subgroup.</p> <p>Conclusion</p> <p>This study shows that p27 and cyclin E are not good independent prognostic markers for early breast carcinoma in contrast to grade, lymph node spread and vascular invasion for all invasive carcinomas. However, cyclin E provides some prognostic value as there is a direct statistical association with the development of distant metastases. Many previous studies have correlated overexpression of cyclin E with an aggressive course. The inverse relationship between p27 and cyclin E expression which has been reported in the literature has been highlighted, but this was not statistically significant. Most cases showed positive p27 expression and negative Cyclin E expression. This may be due to the early stage of the disease.</p

Role of T198 Modification in the Regulation of p27Kip1 Protein Stability and Function

The tumor suppressor gene p27Kip1 plays a fundamental role in human cancer progression. Its expression and/or functions are altered in almost all the different tumor histotype analyzed so far. Recently, it has been demonstrated that the tumor suppression function of p27 resides not only in the ability to inhibit Cyclins/CDKs complexes through its N-terminal domain but also in the capacity to modulate cell motility through its C-terminal portion. Particular interest has been raised by the last amino-acid, (Threonine 198) in the regulation of both protein stability and cell motility

Reduced expression of p27 is a novel mechanism of docetaxel resistance in breast cancer cells

INTRODUCTION: Docetaxel is one of the most effective chemotherapeutic agents in the treatment of breast cancer. Breast cancers can have an inherent or acquired resistance to docetaxel but the causes of this resistance remain unclear. However, apoptosis and cell cycle regulation are key mechanisms by which most chemotherapeutic agents exert their cytotoxic effects. METHODS: We created two docetaxel-resistant human breast cancer cell lines (MCF-7 and MDA-MB-231) and performed cDNA microarray analysis to identify candidate genes associated with docetaxel resistance. Gene expression changes were validated at the RNA and protein levels by reverse transcription PCR and western analysis, respectively. RESULTS: Gene expression cDNA microarray analysis demonstrated reduced p27 expression in docetaxel-resistant breast cancer cells. Although p27 mRNA expression was found to be reduced only in MCF-7 docetaxel-resistant sublines (2.47-fold), reduced expression of p27 protein was noted in both MCF-7 and MDA-MB-231 docetaxel-resistant breast cancer cells (2.83-fold and 3.80-fold, respectively). CONCLUSIONS: This study demonstrates that reduced expression of p27 is associated with acquired resistance to docetaxel in breast cancer cells. An understanding of the genes that are involved in resistance to chemotherapy may allow further development in modulating drug resistance, and may permit selection of those patients who are most likely to benefit from such therapies

Necrosis related HIF-1α expression predicts prognosis in patients with endometrioid endometrial carcinoma

<p>Abstract</p> <p>Background</p> <p>Hypoxia inducible factor 1α (HIF-1α) plays an essential role in the adaptive response of cells to hypoxia and is associated with aggressive tumour behaviour. We have shown p27^kip1, which is generally reduced in endometrial cancer, to be re-expressed in hypoxic regions. This possibly contributes to survival of cancer cells. The aim of this study was to evaluate the prognostic value of HIF-1α and p27^kipexpression in patients with endometrioid endometrial cancer.</p> <p>Methods</p> <p>Expression levels of HIF-1α, CAIX, Glut-1, and p27^kip1were analyzed by immunohistochemistry. Percentage of positive cells, staining pattern (perinecrotic, diffuse, or mixed) and presence of necrosis were noted.</p> <p>Results</p> <p>Necrosis was correlated with shortened disease free survival (DFS) (p <it>= </it>0.008) and overall survival (OS) (p <it>= </it>0.045). For DFS, perinecrotic HIF-1α expression was also prognostic (p <it>= </it>0.044). Moreover, high p27^kip1expression was an additional prognostic factor for these patients with perinecrotic HIF-1α expression. In multivariate Cox regression, perinecrotic HIF-expression emerged as an independent prognostic factor. Perinecrotic HIF-1α expression was significantly associated with CAIX and Glut-1 expression, pointing towards functional HIF-1.</p> <p>Conclusions</p> <p>In patients with endometrioid endometrial cancer, necrosis and necrosis-related expression of HIF-1α are important prognostic factors. More aggressive adjuvant treatment might be necessary to improve the outcome of patients with these characteristics.</p