Gene expression profiling of Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly reveals alterations of characteristic oncogenetic pathways.
Bottom Line: To confirm the results of the expression profiles, in vitro analysis was performed.The results of the present study suggest that activation of the JAK-STAT and NF-κB pathways was characteristic of EBV(+)DLBCL-E, which may reflect the nature of EBV-positive tumor cells.Targeting these pathways as therapies might improve clinical outcomes of EBV(+)DLBCL-E.
Affiliation: Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya, Aichi, Japan; Department of Hematology and Cell Therapy, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan; Department of Cancer Genetics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.Show MeSH
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Mentions: The results of the expression profile suggest that STAT3 and NF-κB activation were characteristics of EBV(+)DLBCL-E. However, it is not clear whether the activation reflected the nature of the tumor cells or the non-tumor cell of the samples, and if STAT3 and NF-κB activation was associated with EBV infection into tumor cells. To investigate the association between EBV-infected B-cell lymphoma cells and molecular pathways, we then conducted in vitro functional analysis. A recombinant EBV harboring EGFP and neomycin resistance genes20 was used to infect five DLBCL cell lines, of which two EBV-infected GCB-like DLBCL cell lines (SUDHL6 and OCI-Ly7) and one EBV-infected ABC-like DLBCL cell line (OCI-Ly3) were successfully established showing ≥90% EGFP positivity (Fig.3a). The protein expression of LMP1 in SUDHL6 and OCI-Ly3 was confirmed; however, the expression level in OCI-Ly7 was quite low (Figs3b, S1). SUDHL6 and OCI-Ly7 cell lines were successfully used in studying the protein expression of EBNA2. Expression of EBNA2 was not detected in both cell lines (Fig. S2). Gene expression profiling of EBV-infected cell lines was compared with cell lines before EBV infection using STAT3- and NF-κB-related gene sets (Table S2). Figure3(c,d) shows that the gene sets of STAT3 and NF-κB were enriched in EBV-infected B-cell lines. To confirm the protein expression level, we performed western blot analysis using the cell lines and found elevation of STAT3 and enhanced pSTAT3 expression after EBV infection into SUDHL6, whereas the expression was not observed in OCI-Ly7 (Fig.3e). The expression level of pSTAT3 of EBV-infected OCI-Ly3 was the same as that of EBV-naïve OCI-Ly3 (Fig. S1).
Affiliation: Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya, Aichi, Japan; Department of Hematology and Cell Therapy, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan; Department of Cancer Genetics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.