ABSTRACT
RPS6KB1 encodes p70S6K/p85S6K, which plays a role in the PI3K/Akt/mTOR signal transduction pathway. CDC2 gene encodes cdc2, which is critical for G2/M cell cycle progression. We had previously shown that amplified RPS6KB1 and CDC2 are commonly detected in the EBV+ diffuse large B-cell lymphoma (DLBCL) in HIV patients. In current study, we further evaluated the amplified RPS6KB1 and CDC2 genes in 12 HIV-related aggressive B-cell lymphomas and 10 non-HIV-related DLBCL using real time quantitative PCR. The cases were divided into 4 groups: 1) HIV-/EBV-; 2) HIV-/EBV+; 3) HIV+/EBV-; and 4) HIV+/EBV+. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) was used to assess the ability of each gene to distinguish non-HIV+/EBV+ cases from HIV+/EBV+ cases. The AUC was estimated to be 0.76 for RPS6KB1 and 0.74 for CDC2 by using the Mann-Whitney statistic. Amplified RPS6KB1 and CDC2 genes were more frequently detected in common variants of DLBCL associated with HIV infection. Taken together, amplified RPS6KB1 and CDC2 are potential biomarkers for the aggressive DLBCL, particularly in HIV+/EBV+ patients. This study also suggests that the HIV+/EBV+ aggressive DLBCL could be potentially treated by targeting RPS6KB1 and CDC2 genes.
Subject(s)
Cyclin B/genetics , Epstein-Barr Virus Infections/complications , HIV Infections/complications , Lymphoma, AIDS-Related/genetics , Lymphoma, Large B-Cell, Diffuse/genetics , Ribosomal Protein S6 Kinases, 70-kDa/genetics , Biomarkers, Tumor/genetics , CDC2 Protein Kinase , Cell Division/genetics , Cyclin-Dependent Kinases , G2 Phase/genetics , Humans , Lymphoma, AIDS-Related/pathology , Lymphoma, AIDS-Related/virology , Lymphoma, Large B-Cell, Diffuse/pathology , Lymphoma, Large B-Cell, Diffuse/virology , ROC Curve , Signal Transduction/geneticsABSTRACT
PURPOSE: This study aimed to identify and evaluate molecular targets for the development of a novel combination chemotherapy to treat refractory and recurrent diffuse large B-cell lymphoma (DLBCL). EXPERIMENTAL DESIGN: Lymphoma samples from 38 cases of primary and recurrent DLBCL were analyzed using real-time quantitative PCR of the RPS6KB1 and CDC2 genes, and immunohistochemistry for their gene products p70S6K/p85S6K and cdc2/cdk1. The Farage, Karpas422, Pfeiffer, and Toledo DLBCL cell lines were subsequently treated with rapamycin and UCN-01 alone or in combination. Cell proliferation, apoptosis, and cell cycle progression were analyzed after the drug treatment. In addition, the levels of several key protein kinases involved in the phosphoinositide 3'-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, apoptosis, and cell cycle progression were analyzed in the presence and absence of the drugs. RESULTS: Amplification of the RPS6KB1 and CDC2 genes was found in both primary and recurrent DLBCL. Moreover, the vast majority of these lymphomas (approximately 94%) were strongly positive for phospho-p70S6K and cdc2/cdk1 proteins. The combination of rapamycin and UCN-01 synergistically inhibited the DLBCL cell proliferation by inducing G1 arrest as well as apoptosis by suppressing the phosphorylation of p70S6K/p85S6K and CDC2 expression. CONCLUSION: RPS6KB1 and CDC2 overexpression is common in DLBCL. Simultaneously targeting the RPS6KB1 and CDC2 products phospho-p70S6K/p85S6K and cdc2/cdk1 is very effective in inhibiting DLBCL proliferation and overcoming drug resistance. This work suggests that multilevel inhibition of the PI3K/Akt/mTOR pathway and double-block of cell cycle progression are effective strategies for DLBCL therapy.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , CDC2 Protein Kinase/metabolism , Cyclin B/metabolism , Lymphoma, Large B-Cell, Diffuse/pathology , Neoplasm Recurrence, Local/pathology , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Adult , Aged , Aged, 80 and over , Apoptosis/drug effects , Blotting, Western , CDC2 Protein Kinase/genetics , Cell Proliferation/drug effects , Cyclin B/genetics , Cyclin-Dependent Kinases , Drug Synergism , Female , Flow Cytometry , G1 Phase/drug effects , Gene Expression Profiling , Humans , Immunoenzyme Techniques , Lymphoma, Large B-Cell, Diffuse/metabolism , Male , Middle Aged , Neoplasm Recurrence, Local/metabolism , Oligonucleotide Array Sequence Analysis , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation/drug effects , Protein Kinases/genetics , Protein Kinases/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Ribosomal Protein S6 Kinases, 70-kDa/genetics , Sirolimus/administration & dosage , Staurosporine/administration & dosage , Staurosporine/analogs & derivatives , TOR Serine-Threonine Kinases , Tumor Cells, CulturedABSTRACT
Primary gastric T cell lymphoma is rare and mostly of large cell type. In this paper, we present a case of gastric T cell lymphoma morphologically similar to the gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT). Morphologically, the cells are small with abundant clear cytoplasm. Lymphoepithelial lesions are readily identified with diffuse destruction of gastric glands. Immunohistochemically, the neoplastic cells are CD3+/CD4+/CD8-/Granzyme B-. Molecular studies revealed monoclonal T cell receptor gamma gene rearrangement. Clinically, the patient responded initially to four cycles of R-CHOP, but then progressed. Because peripheral T cell lymphoma is usually associated with a poor prognosis, whereas marginal zone B cell lymphoma is an indolent lymphoproliferative disorder, this morphologic mimicry should be recognized and completely investigated when atypical small lymphoid infiltrates with lymphoepithelial lesions are encountered in the stomach.
