miR-204 inhibits proliferation of Hodgkin lymphoma cells by targeting Sirt1/p53 signaling pathway

AIM: To investigate the effect of microRNA-204 (miR-204) on the proliferation of Hodgkin lymphoma cells and the underlying mechanism. METHODS: The expression of miR-204 and Sirt1 mRNA in Hodgkin lymphoma tissues was detected by RT-qPCR. After transfection with miR-204 mimic, Sirt1 siRNA and miR-204 mimic+pcDNA3.1-Sirt1 into the L428 cells, the cell viability and BrdU incorporation were measured by CCK-8 assay and BrdU assay, respectively. The protein levels of Sirt1 and acetylated p53 (ac-p53) were determined by Western blot.The targeting relationship between miR-204 and Sirt1 was verified by double luciferase reporter assay. RESULTS: The low expression of miR-204 and the high mRNA expression of Sirt1 were found in the Hodgkin lymphoma tissues. Compared with control group, the cell viability, BrdU incorporation and the protein levels of Sirt1 and ac-p53 were significantly decreased after L428 cells were transfected with miR-204 mimic or Sirt1 siRNA (P<0.05). Compared with miR-204 mimic alone group, the cell viability, BrdU incorporation and the protein levels of Sirt1 and ac-p53 were increased after L428 cells were co-transfected with miR-204 mimic and pcDNA3.1-Sirt1 (P<0.05). The results of double luciferase reporter assay confiermed that Sirt1 was the target gene of miR-204. CONCLUSION: The inhibitory effect of miR-204 on the proliferation of L428 cells may be achieved by inhibiting the expression of Sirt1 and promoting the up-regulation of ac-p53.     

Evaluation of Pax5 expression and comparison with BLA.36 and CD79αcy in feline non‐Hodgkin lymphoma

Paired box gene 5 (Pax5) is a widely used B‐cell marker for human and canine non‐Hodgkin's lymphoma (nHL); however, in the literature there is only one case report using Pax5 in a cat B‐cell lymphoma. The purposes of this study were to investigate the expression and detection of B‐cell specific activator protein (BSAP) using a monoclonal anti‐Pax5 antibody in feline nHL (FnHL) tissue samples to evaluate its diagnostic relevance as a B‐cell marker. A total of 45 FnHL samples in 45 cats were evaluated. B‐cell lymphoma was the most common immunophenotype (51.1%) for all the samples and T‐cell the most common immunophenotype (64.3%) for the gastrointestinal (GI) form. Pax5 stained 82.6% of all B‐cell lymphomas and no expression was found in any of the T‐cell lymphomas. Anti‐Pax5 antibody staining in FnHL is similar to that reported in human and canine counterparts and may offer an excellent B‐cell marker in cats.     

Epigenetic modification by 5-Aza/TSA treatment induces loss of B-cell phenotype in B-cell derived non-Hodgkin lymphoma

AIM: To investigate influence of demethylation/acetylation by 5-Aza-2'-deoxycytidine/trichostatin A (5-Aza/TSA) treatment on B-cell specific phenotype of non-Hodgkin lymphoma cells. METHODS: CD19 promoter-driven reporter with NEO cassette was constructed to realize transfection and stable selection of Hodgkin and non-Hodgkin lymphoma cells. The exogenous CD19 promoter activity in both cell line clusters with and without 5-Aza/TSA treatment was detected and compared. The B-cell specific expression profiling in Eμ-myc transgenic mouse model developed lymphoma was isolated and identified. The effects of 5-Aza/TSA treatment on B-cell specific phenotype were analyzed. RESULTS: Epigenetic modification via 5-Aza/TSA repressed B-cell specific phenotype in B-cell-derived non-Hodgkin lymphoma cells. CONCLUSION: Epigenetic modification of pivotal master repressor genes plays an essential role in B-cell phenotype of both human and murine developed B-cell non-Hodgkin lymphoma cells.     

Expression and significance of c-IAP2 and GAS1 in Hodgkin's lymphoma and anaplastic large cell lymphoma

AIM: To detect the expression of cytoplasmic inhibitor of apoptosis protein 2 (c-IAP2) and growth arrest-specific gene 1 (GAS1) in Hodgkin's lymphoma (HL) and anaplastic large cell lymphoma (ALCL) and to investigate the role of two genes in the pathogenesis of HL and ALCL.METHODS: HE staining, the antibodies CD30, CD15, CD45RO and CD20 were used to screen the cases of HL and ALCL from 288 cases of lymphoma. The clarified HL and ALCL were subjected for immunohistochemical staining by SP and ABC methods to analyze the expression of c-IAP2 and GAS1. RESULTS: ①The positive rate of c-IAP2 in HL was 25/26(96.1%) while that in ALCL was 6/19(31.6%), there presented statistic significance between HL and ALCL groups(P<0.05), meanwhile the positive rate of GAS1 showed statistic significance between HL and ALCL groups(P<0.05). ②Two cases were showed to be a mixed type combined with large tumor cells of HL and relatively smaller tumor cells of ALCL.CONCLUSION: ①The different expression of c-IAP2 and GAS1 in HL and ALCL implied a different mechanism of oncogenesis and the different defects in the pathway of signal transduction of apoptosis in HL and ALCL;②Few cases showed an overlap and a likely transitional state between HL and ALCL; ③The different expressing manner of GAS1 and c-IAP2 in HL and ALCL implied the potential marks for the differential dignosis of two kinds of lymphoma.     

Expression of caspase-4 in Hodgkin's lymphoma and anaplastic large cell lymphoma

AIM: This study is based on the result of the study in HL and ALCL employing gene chip technique, in which writer found that there was distinctly different expression of caspase-4 between HL and ALCL cell lines at the level of mRNA. From the point of view, we try to identify at the level of protein whether there is different expression of this gene in HL and ALCL tissues as well. METHODS: HE staining, the monoclonal antibodies CD30 (BerH2), CD15 (C3D-1), CD20 (L26) and CD45RO (UCHL1) were used for selecting the cases of HL and ALCL. Specific high affinitive anti-caspase-4 polyclonal antibody was used by immunohistochemical staining to analyze the expression of caspase-4 in 18 cases of HL and 15 cases of ALCL. RESULTS: The expression of caspase-4 demonstrated a strong positive staining in all ALCL cases (15/15,100%), whereas negative in 16 HL cases (88.8%), while other two cases were weakly stained (11.2%), showing a distinct difference (P<0.01) between two groups. CONCLUSIONS: (1) The diverse expression of caspase-4 gene in HL and ALCL groups implies a different mechanism of oncogenesis and the different defects of signal transduction pathway of apoptosis in these two entities of lymphomas. (2) Clarification of this gene might be useful for the differential diagnosis of HL and ALCL. Furthermore, it probably provides theoretically gene therapy strategies for lymphoma in the future.