Establishment and characterization of a nude mice model of human diffuse large B-cell lymphoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To establish a diffuse large B-cell lymphoma (DLBCL)-mice model using human DLBCL cell line LY8, to investigate its characteristics of growth and to provide a model for in vivo study of DLBCL pathogenesis and treatment.</p><p><b>METHODS</b>LY8 cells were injected subcutaneously into the right flank of nude mice. Harvested tumor tissues were cut into small pieces of 1.5 mm × 1.5 mm × 1.5 mm and implanted subcutaneously into nude mice. Tumor growth was visualized and the histologic characteristics were documented. Expression of LCA, CD20, CD79α, Ki-67, CD3, CD45RO, bcl-6, MUM-1, CD10 and bcl-2 were examined by using immunohistochemistry. IgH clonal rearrangement and status of three microsatellite loci (D14S68, D18S69, D20S199) in the xenografted tumor samples and the parental cell line LY8 were detected using PCR amplification followed by PAGE.</p><p><b>RESULTS</b>The subcutaneous xenograft DLBCL model was successfully established by using cell line LY8, and a stable growth was achieved up to the 9th generation. The tumor in each generation showed similar growth characteristics and the rate of subcutaneous tumor formation was 91.9% (114/124). The tumor growth was observed from the 2nd week after implantation, reaching 1.3 cm in major diameter at the 3rd week and 2.0 cm at the 4th week. The tumor had identical morphological characteristics with those of human DLBCL, and expressed LCA, CD20, CD79α, bcl-6, MUM-1, CD10 and bcl-2. The tumor of xenograft mice and cell line LY8 showed identical IgH rearrangement and microsatellite length.</p><p><b>CONCLUSIONS</b>A human DLBCL bearing mouse model was successfully established. The mice model is similar to human counterpart with high stability and repeatability. Therefore, it provides an ideal animal model for in vivo studies of the biological characteristics and treatment of DLBCL.</p>

Study on PI3K inhibitor LY294002 for chemotherapeutic sensitization in diffuse large B cell lymphoma cell lines / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects on chemotherapeutic sensitization of the PI3K inhibitor LY294002 in diffuse large B cell Lymphoma (DLBCL) cell lines ly1, ly8, ly10.</p><p><b>METHODS</b>The three cell lines were treated with LY294002, or doxorubicin alone or combined or sequentially respectively. Western blotting was used to detect the level of phospho-AKT after the treatment. Flow cytometry combined with annexin V-FITC assay and Brdu incorporation assay were used to analyze the alterations of cell cycle, proliferation, and apoptosis, respectively.</p><p><b>RESULTS</b>LY294002 decreased the level of phospha-AKT efficiently in the three DLBCL cell lines. The ratio of S phase cells was significantly decreased (P < 0.05). Sequential use of LY294002 and doxorubicin increased the ratio of apoptosis and there was significant difference between the sequential group and the other four groups (P < 0.05) at 24, 48, 72(ly1), 48, 72 (ly8) or 24 h (ly10).</p><p><b>CONCLUSION</b>LY294002 can sensitize doxorubicin-induced apoptosis and may be a potential molecular therapeutic agent targeted at AKT signaling pathway in DLBCL.</p>

Effects of AKT protein kinase activation on biologic behavior of diffuse large B cell lymphoma cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To observe the status of AKT and phospho-AKT (pAKT) in three diffuse large B cell lymphoma (DLBCL) cell lines, and to investigate the effects of AKT activation on biologic behavior of DLBCL cells.</p><p><b>METHODS</b>Three DLBCL cell lines, ly1, ly8 and ly10 were maintained in 10% FBS or serum free culture medium. The expression of AKT and status of pAKT were detected by Western blotting. LY294002, an inhibitor of PI3K, was used to suppress the level of pAKT. Flow cytometry combined with PI staining, AnnexinV-FITC assay and Brdu incorporation assay were used to analyze the parameters of the cell cycle, apoptosis and proliferation respectively.</p><p><b>RESULTS</b>There was constitutive activation of AKT in three DLBCL cell lines and the levels of pAKT were altered in the different environments. In 10% FBS culture medium, pAKT was higher than that in serum free culture medium in ly8 and ly10, however, pAKT in ly1 maintained in serum free culture medium was mildly higher than that in 10% FBS culture medium. When the cell lines ly1, ly8, ly10 were maintained in 10% FBS culture medium, the inhibitor LY294002 suppressed the level of pAKT efficiently in three DLBCL cell lines. The percentage of cells at S phase and the proliferation index were significantly decreased (P < 0.05) without an increase of apoptosis (P > 0.05).</p><p><b>CONCLUSIONS</b>Activation of AKT may play an important role in the development of DLBCL. It is closely related to the control of cell cycle and proliferation, but is not associated with apoptosis. LY294002 can inhibit cell growth by decreasing the levels of pAKT in DLBCL cell lines.</p>