[Mechanism about LMP1 of EB Virus Promoting Plasma Blast Differentiation of DLBCL Cell via mTORC1]

To investigate possible mechanism on protien LMP1 expressed by EBV inducing plasmablast differentiation of DLBCL cell via the mTORC1 pathway.

The expression levels of LMP1 protein, CD38 and the phosphorylation levels of p70S6K in EBV⁺ and EBV^- DLBCL cell lines were detected by Western blot. Cell lines overexpressing LMP1 gene stablely were constructed and LMP1 gene was silenced by RNAi. The expression of LMP1 gene was verified by RT-qPCR. The expression levels of LMP1 and CD38 and the phosphorylation levels of p70S6K in each group were detected by Western blot.

Compared with EBV^-DLBCL cells, the expression of LMP1 was detected on EBV ⁺DLBCL cells (P =0.0008), EBV ⁺DLBCL cells had higher phosphorylation levels of p70S6K (P =0.0072) and expression levels of CD38(P =0.0091). Compared with vector group, the cells of LMP1^OE group had higher expression levels of LMP1 and CD38 (P =0.0353; P <0.0001), meanwhile molecular p70S6K was phosphorylated much more(P =0.0065); expression of LMP1 mRNA was verified(P <0.0001). Compared with si-NC group, expression level of LMP1 protein(P =0.0129) was not detected and phosphorylated p70S6K disappeared of LMP1^KO group (P =0.0228); meanwhile, expression of CD38 decreased,although there was no significant difference (P =0.2377).

LMP1 promotes DLBCL cells plasmablast differentiation via activating mTORC1 signal pathway.