Tissue microarrays (TMAs) are potentially suited to find associations between molecular features and clinical outcome. Enhanced cell proliferation, as measured by Ki67 immunohistochemistry, is related to poor patient prognosis in many different tumor types. Ki67 expression shows considerable intratumoral heterogeneity. It is unclear if the TMA format is suitable for the analysis of potentially heterogeneous markers because of the small size of TMA spots. We have analyzed a breast cancer TMA containing 2,517 breast tissues, including 2,222 neoplastic and 295 normal or premalignant samples, for Ki67 labeling index (Ki67 LI) and additional markers with a known relationship to Ki67 LI by immunohistochemistry (ER, PR, Bcl-2, Egfr, p16, p53) and Fluorescence in situ hybridization (HER2, MDM2, CCND1, MYC). A high Ki67 LI was linked to tumor phenotype including grade (p < 0.0001), stage (p < 0.0001), nodal stage (p = 0.0018), and patient prognosis (p < 0.0001), elevated protein levels of p53, p16 and Egfr, reduced levels of Bcl2, ER, and PR (p < 0.0001 each), as well as amplifications of HER2, MYC, CCND1 and MDM2 (p < 0.0001 each). In summary, all expected associations between Ki67 and the analyzed molecular markers could be reproduced with high statistical significance using a TMA containing only one tissue sample per tumor, measuring 0.6 mm in diameter. We conclude that associations with cell proliferation can be reliably analyzed in a TMA format.

Curcumin has been shown to possess variety of biological functions including anti-tumor activity. The mechanism by which curcumin inhibit cell proliferation remains poorly understood. In the present report, we investigated the effect of curcumin on the activation of apoptotic pathway in T-cell acute lymphoblastic leukemia (T-ALL) malignant cells. Our data demonstrate that curcumin causes dose dependent suppression of proliferation in several T cell lines. Curcumin treatment causes the de-phosphorylation/inactivation of constitutively active AKT, FOXO transcription factor and GSK3. Curcumin also induces release of cytochrome c accompanied by activation of caspase-3 and PARP cleavage. In addition, zVAD-fmk, a universal inhibitor of caspases, prevents caspase-3 activation and abrogates cell death induced by curcumin treatment. Finally, treatment of T-ALL cells with curcumin down-regulated the expression of inhibitor of apoptosis protein (IAPs). Taken together, our finding suggest that curcumin suppresses constitutively activated targets of PI3'-kinase (AKT, FOXO and GSK3) in T cells leading to the inhibition of proliferation and induction of caspase-dependent apoptosis.

SummaryModern research technologies, including DNA, protein, and antibody microarrays identify a steadily growing number of clues that are useful in molecular disease classification, drug development, and the prediction of response to treatment. Subsequent validation of the clinical importance of such candidate genes or proteins requires large-scale analysis of human tissues. To date, this analysis constitutes an important bottleneck in the process of discovery because tissue analysis by the conventional slide-by-slide strategy is slow and expensive. To overcome these limitations, tissue microarray (TMA) technology has been developed. TMA allows for the simultaneous analysis of up to 1,000 tissue samples in a single experiment, using all types of in-situ analyses including immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and RNA in situ hybridization (RNA-ISH). TMA technology has the potential to greatly facilitate the translation of basic research into clinical practice. Potential applications include the establishment of associations between molecular changes and clinical endpoints, testing of potential therapeutic targets using tissue samples from specific cancer patients, standardization of molecular detection of targets, and rapid translation of results from cell lines and animal models to human cancer. Because of its beneficial economic aspects and ability to differentiate ethnic differences in tumor biology, TMA applications may become particularly important in developing countries.

Recent studies have suggested a potential prognostic role of alterations of the fragile histidine triad (FHIT) gene in diffuse large B-cell lymphoma. To evaluate possible mechanisms of FHIT inactivation and to further clarify its potential prognostic relevance, we analyzed a set of 114 diffuse large B-cell lymphoma with clinical follow-up information. Tissue microarrays were analyzed by immunohistochemistry for protein expression, and corresponding DNA samples were analyzed for FHIT promotor hypermethlyation. Reduced or absent FHIT expression was found in 75 of 114 diffuse large B-cell lymphoma (66%), but was unrelated to clinical tumor stage or patient prognosis. FHIT promotor hypermethylation was observed in 29 of 93 (23%) interpretable diffuse large B-cell lymphoma. Hypermethylation was not significantly correlated to protein expression loss, which could be explained by competing mechanisms for FHIT inactivation in a substantial fraction of non FHIT hypermethylated diffuse large B-cell lymphoma. Hypermethylation was significantly associated with poor prognosis of diffuse large B-cell lymphoma patients and predominantly seen in nongerminal center diffuse large B-cell lymphoma (27%), but less frequent (13%) in germinal center diffuse large B-cell lymphoma. In summary, these data suggest that promotor hypermethylation is responsible for reduced FHIT expression in a substantial subset of diffuse large B-cell lymphoma, which is primarily composed of nongerminal center subtype with poor patient prognosis.

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Fatty acid synthase (FASN), the enzyme responsible for de novo synthesis of fatty acids has been shown to be deregulated in several cancers including epithelial ovarian carcinoma (EOC). In this study, we investigated the function of Fatty acid Synthase (FASN) signaling pathway in a large series of middle eastern EOC patient samples, using a panel of cell lines, and nude mouse model. Using immunohistochemistry, we detected FASN in 75.5 %(114/151) tumor samples. Overexpression of FASN was significantly associated with tumor proliferative marker Ki-67 (p=0.0009), activated AKT (p=0.0117) and XIAP(p=0.0046). Treatment of EOC cell lines with C75 a selective inhibitor of FASN causes inhibition of EOC cell proliferation via induction of apoptosis. Inhibition of FASN by C75 led apoptosis via involving mitochondrial pathway, activation of caspases and downregulation of XIAP, and survivin. FASN inhibition causes down regulation of activated AKT. In addition, inhibition by FASN siRNA causes downregulation of FASN and activation of caspases suggesting the role of FASN in C75 mediated apoptosis. Furthermore, treatment of EOC cells with subtoxic doses C75 augmented the effect of cisplatin mediated inhibition of cell proliferation and induction of apoptosis. Finally, treatment of EOC cell line xenografts with combination of C75 and cisplatin resulted in growth inhibition of tumors in nude mice through downregulation of FASN and activation of caspases Altogether, our results suggest that overexpression of FASN in Middle eastern EOC suggests that FASN may be a potential therapeutic target in a subset of EOC, alone or in combination with other conventional chemotherapeutic agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1002. doi:10.1158/1538-7445.AM2011-1002

Diffuse large B-cell lymphoma (DLBCL) belongs to the most common malignancies in Saudi Arabia, accounting for 50–60% of adult non-Hodgkin Lymphomas. DLBCL represents a heterogeneous group of tumors with respect to morphology, genetics, and clinical behaviour. The two major subtypes of DLBCL differ in their site of origin, i.e. within (nodal) or outside (extranodal) the lymph nodes, and a separate genetic pathway has been suggested for these subtypes. To detect potential biological differences between these two DLBCL categories, we performed gene expression analysis in 20 nodal and 8 extranodal lymphoma tissues, as well as in 4 normal lymph nodes, using the GeneChip technology (Affymetrix HG-U133_2 array). Data analysis using the D chip software highlighted a total of 215 genes expression patterns of which were significantly different in nodal and extranodal lymphomas. The most striking differences were observed for genes contributing in ATP binding (20 genes), nucleotide binding (12 genes), response to stress (19 genes), RNA metabolism (6 genes), protein translation (4 genes), and inflammatory response (4 genes). Remarkably, also 5 protein tyrosine kinases were found to be differentially expressed. Our data strongly suggests the existence of at least two different genetic pathways for the development of nodal and extranodal DLBCL, which are characterized by these genetic changes. These results prompt for further expression analysis in large cohorts of histomorphologically well defined lymphoma tissues in order to evaluate the clinical relevance of these alterations.