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Asim Belgaumi

Publications and source records attributed to Asim Belgaumi.

4 recordsLinked to original sources

Role of phosphatidylinositol 3'-kinase/AKT pathway in diffuse large B-cell lymphoma survival.

Phosphatidylinositol 3'-kinase (PI3K) is a key player in cell-growth signaling in a number of lymphoid malignancies, but its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. Therefore, we investigated the role of the PI3K/AKT pathway in a panel of 5 DLBCL cell lines and 100 clinical samples. Inhibition of PI3K by a specific inhibitor, LY294002, induced apoptosis in SUDHL4, SUDHL5, and SUDHL10 (LY-sensitive) cells, whereas SUDHL8 and OCI-LY19 (LY-resistant) cells were refractory to LY294002-induced apoptosis. AKT was phosphorylated in 5 of 5 DLBCL cell lines and inhibition of PI3K caused dephosphorylation/inactivation of constitutively active AKT, FOXO transcription factor, and GSK3 in LY-sensitive cell lines. In addition, there was a decrease in the expression level of inhibitory apoptotic protein, XIAP, in the DLBCL cell lines sensitive to LY294002 after treatment. However, no effect was observed in XIAP protein levels in the resistant DLBCL cell lines following LY294002 treatment. Finally, using immunohistochemistry, p-AKT was detected in 52% of DLBCL tumors tested. Furthermore, in univariate analysis, high p-AKT expression was associated with short survival. In multivariate analysis, this correlation was no longer significant. Altogether, these results suggest that the PI3K/AKT pathway may be a potential target for therapeutic intervention in DLBCL.

Apoptosis↗

High throughput tissue microarray analysis of FHIT expression in diffuse large cell B-cell lymphoma from Saudi Arabia.

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.

Acid Anhydride Hydrolases↗

Epstein-Barr virus infection is not the sole cause of high prevalence for Hodgkin's lymphoma in Saudi Arabia.

The age-adjusted incidence of Hodgkin's lymphoma (HL) is markedly higher in Saudi Arabia than in the USA, and accounts for 10.5% of all neoplasias in children aged 15 years or older in Saudi Arabia. Epstein-Barr virus (EBV) infection has been suspected to cause high HL incidence in developing countries. To investigate the role of EBV for the high frequency of HL in Saudi Arabia, we analysed 169 HLs from Saudi Arabia and 30 HLs from Europe for EBV infection by in situ hybridization with fluorescence in-conjugated EBV on tissue microarray sections. All Saudi Arabian and European HLs were analysed in one experiment under identical conditions. Unexpectedly, our data show only minor, insignificant differences in EBV infection rates between Saudi Arabian (42 out of 147 informative cases 28.6%) and European HL (nine out of 30 informative cases; 30%; P = 0.8752). Within the Saudi Arabian population, EBV infection was most frequently seen in mixed cellularity HL (52.4%). This was significantly more frequent than in nodular sclerosing HL (26.1%; P = 0.0236). EBV positivity was unrelated to patient prognosis. In conclusion, our data strongly suggest that EBV is not the main cause for the high prevalence of HL in Saudi Arabia. This would be consistent with a major role of genetic susceptibility genes for HL in these populations. The Saudi Arabian population, with high consanguinity and large families, would prove ideal for identifying HL susceptibility genes.

Adolescent↗