Expression Of SEL1L And BCL2,BCL6 In Diffuse Large B Cell Lymphoma And Its Significance

Background:Diffuse large B cell lymphoma(DLBCL)is a group of invasive lymphoma that is heterogeneous in morphology,genetics,immunophenotype and clinical manifestations.It is the most common non-Hodgkin's lymphoma(NHL)and accounts for about 30-40%of all NHLs.DLBCL mostly occurs in the elderly though they are not restricted to any age group and the median age is in the 7th decade.Currently the standard clinical treatment program is R-CHOP,but 30%to 40%of patients still have ineffective treatment or rapidly relapse.The prognosis is poor.Exploring the relationship between gene function and the development of DLBCL is helpful to study the pathogenesis of DLBCL and provide a theoretical basis for clinical treatment.The SEL1L gene(human Sel-l-like gene)is located on human chromosome 14q23.3-q31 and was first isolated from human chromosomes by Biunno.I et al.in 1997,similar to the C.elegans sel-1 gene sequence.In recent years,SEL1L has been studied in many tumors.Orlandi.et al.found that SEL1L was underexpressed in about 78 of 117 breast cancer cases.Overall survival analysis showed that low SEL1L expression was associated with poor prognosis.Granelli.et al.found that SEL1L mRNA and protein were not detected in normal esophageal squamous epithelium but highly expressed in esophageal squamous cell dysplasia and esophageal cancer,so they supposed that SEL1L may be used as a biomarker to identify patients at high risk of esophageal cancer.The expression of SEL1L in lymphoma and its significance have not been reported at home and abroad till now.Object:To investigate the expression of SEL1L and BCL2,BCL6 in Diffuse Large B cell Lymphoma and its significances.Methods:(1)The expression of SEL1L,BCL2 and BCL6 protein in 123 cases of DLBCL and the expression of SEL1L in 60 cases of reactive lymphoid tissue(RLH)were detected by immunohistochemistry.(2)The expression of SEL1L protein in DLBCL cell lines LY-10 and SUDHL-4 was detected by Western Blot.(3)Three siRNA-SELIL(siRNA-983,siRNA-1666 and siRNA-200)were designed to interfere with the expression of SEL1L in DLBCL cell lines.Negative control group(siRNA-NC)and blank control group(Mock)were also established.(4)DLBCL cell lines LY10 and SUDHL-4 were transfected with siRNA-SEL1L by LipofectamineTM3000.After 48 hours of transfection,the cells were harvested,and the amount of SEL1L mRNA and SEL1L protein were detected by RT-PCR and Western blot.(5 MTT,the flow cytometry and transwell chamber experiment were used to explore the proliferation,apoptosis and invasion ability of transfected cells.(6)Western Blot was used to detect of BCL2 expression after transfection.Results:(1)The high expression rate of SEL1L was 69.9%in 123 DLBCL,which was significantly higher than that in 60 RLH(25.0%).The expression of SEL1L protein in DLBCL was not related to clinicopathological parameters.The positive rate of BCL2,BCL6 was 83.7%and 61%respectively in 123 DLBCL.The expression of BCL2 protein was correlated with immunophenotyping,primary location,and Ann Arbor stage.The expression of SEL1L protein was positively correlated with that of BCL-2 protein in DLBCL.The expression of BCL6 protein was correlated with immunophenotyping.The expression of SEL1L protein didn't show correlated with that of BCL6 protein in DLBCL.(2)Western blot showed that SEL1L protein was high expressed in LY-10 and SUDHL-4 cell lines.(3)After transfecting three siRNA-SELIL transfected cells,the mRNA and protein expression of was significantly lower than that of siRNA-NC group and Mock group,and the most significant decrease was siRNA-1666.(4)The results of MTT showed that the proliferation ability of siRNA-SELIL group was significantly lower than that of siRNA-NC group and Mock group(P<0.05).(5)The flow cytometry showed that the apoptosis ratio of siRNA-SELIL group was significantly higher than that of siRNA-NC group and Mock group(P<0.05).(6)Transwell chamber experiments showed that the invasion and migration ability of siRNA-SEL1L group was lower than that of siRNA-NC group and Mock group(P<0.05).(7)The expression of BCL2 did not change significantly after transfection of siRNA-SEL1L(P>0.05).Conclusion:SEL1L protein was high expressed in DLBCL tissues and cell lines.And,the down-regulation of SEL1L expression can inhibit cell proliferation and invasion and promote apoptosis.Therefore,we supposed that SEL1L may play an important role in the development of DLBCL.Inhibition of SEL1L expression may be a new way to treat DLBCL.