The Role And Mechanism Of LHPP In B-cell Non-hodgkin Lymphoma

Background and ObjectiveB-cell non-Hodgkin’s lymphoma(B-NHL)is a B-cell malignant tumor.Although its therapeutic effect has been greatly improved in recent years,treatment outcome of relapsed and/or refractory B-NHLis not very satisfied,thus searching novel targeting points is required.Phospholysine phosphohistidine inorganic pyrophosphate phosphatase(LHPP)is a histidine phosphatase,whose expression is found to be low in various solid tumors.However,the expression and potential role of LHPP in B-NHL have not been reported.We mean to clarify the expression of LHPP and relationship of LHPP with prognosis in patients with B-NHL,and further explore mechanism throgh testing the proliferation,apoptosis,cycle and chemosensitivity of B-NHL cell line.It provides a new idea for prognostic assessment and targeted therapy of B-NHL.MethodsThe data of laboratory indexes,clinical classification and overall survival of 80 patients with new-diagnosed B-NHL were collected.The protein expression level of LHPP in lymph nodes biopsy from B-NHL patients was detected by immunohistochemistry.20 patients with reactive lymphoid hyperplasia were served as control.The relationship between the expression level of LHPP and prognosis was further analyzed.The m RNA expression level of LHPP in B-NHL cell line was detected by RT-PCR,and the B-NHL cell lines with lower expression of LHPP were selected for subsequent functional experiments.The overexpressed LHPP stable cell lines,LV-LHPP-Raji and LV-LHPP-SJC,were established through transfection with LHPP-containing lentivirus followed by selection with puromycin.The transfection efficiency was tested and verified by fluorescence inverted microscope,flow cytometry,RT-PCR and Western blot.Furthermore,the proliferation,apoptosis and cytocycle of LV-LHPP-Raji and LV-LHPP-SJC were explored by CCK-8 and flow cytometry.The LV-Control-Raji and LV-Control-SJC cell lines were served as controls.The sensitivity of LV-LHPP-Raji and LV-LHPP-SJC to Cisplatin(DDP)also was assessed by testing the proliferation,apoptosis and cytocycle of cell lines.ResultCompared with patients with reactive lymph node hyperplasia,the expression level of LHPP in lymphoid tissue of B-NHL patients was significantly lower,and the difference was statistically significant(P<0.05).The 3-year survival rate of B-NHL patients with low expression of LHPP was lower than that of B-NHL patients with high expression of LHPP(P < 0.05).The expression level of LHPP can be used to judge the prognosis of B-NHL patients.The expression level of LHPP in B-NHL cell line was significantly lower than that in the control group.We established LV-LHPP-Raji and LV-LHPP-SJC cell lines that stably overexpressed LHPP.Compared with LV-Control-Raji and LV-Control-SJC cells,LV-LHPP-Raji and LV-LHPP-SJC cell lines that overexpress LHPP have decreased proliferation ability,increased apoptosis and decreased G2/M phase cells.When cells were treated with cisplatin,it was found that compared with the control,the proliferation ability of LV-LHPP-Raji and LV-LHPP-SJC cell lines decreased significantly,apoptosis increased,and G2/M phase cells decreased.The inhibition of cell proliferation was time-dependent and concentration-dependent.The IC50 value of cisplatin in LV-LHPP-Raji and LV-LHPP-SJC strains was lower than that in the control group.ConclusionIn this study,the expression and clinical significance of LHPP in B-NHL were studied for the first time.It was found that the expression level of LHPP in B-NHL patients was significantly decreased,and the prognosis of patients with high expression of LHPP was better.Overexpression of LHPP in B-NHL cell lines can inhibit proliferation,promote apoptosis,block the cell cycle and enhance their sensitivity to cisplatin.