| Objectives: Human gliomas mostly derived from glial cells,belong to neuroepithelial tumors,accounting for about 27% of all tumors in the central nervous system.Glioma is the most common malignant tumor in intracranial primary,accounting for about 80%.Glioblastoma(GBM,WHO Ⅳ)is the most common primary malignant tumor in the central nervous system,accounting for about 46%,and the incidence rate of male is higher than that of female.Glioma has clinical characteristics such as insidious onset,rapid growth,relatively high degree of malignancy,poorly circumscribed,and invasive growth.The current treatment of the glioma is poor.In primary intracranial tumors,glioma patients Mortality is the highest,and the median survival time is only about one year.Like other malignant tumors,glioma development is a multi-step,multi-factor process,and the exact mechanism remains to be further studied.With the progress of science and technology,tumor suppressors,which are closely related to the development and progression of gliomas,are found gradually,with the development of detection methods and molecular biology,molecular genetics.It will give impetus to find target gene or target protein for glioma,classify glioma,develop molecular targeted drug and judge prognosis when more glioma-associated tumor suppressor factor was found.On the basis of the present study,three abnormal signal transduction pathways have been found to be part of the development of glioma,including EGFR / PTEN / PI3 K pathway,Rb-E2 F / CDK4,6 / P16-cyclin D pathway,P53 / MDM2 / P12,P21 pathway.The INPP4 B gene,a potential tumor suppressor gene,is located on human chromosome 4q31.21,encoding a phosphatidylinositol 4-phosphatase type II(INPP4B)Enzyme.According to the results of the present study,as a potential tumor suppressor,absent or abnormal expression of INPP4 B has been found in many malignant tumors,such as in leukemia,breast cancer,adenocarcinoma,melanoma,liver cancer and gastric cancer.INPP4 B dephosphorylates the D4 group of phosphatidylinositol 3,4-bisphosphate(PI(3,4)P2),and the product of which is phosphatidylinositol 3-phosphate(PI(3)P)PI(3,4)P2 activates AKT.With the decreased of PI(3,4)P2,PI3 K / AKT signaling pathway is inhibited and tumorigenesis has been suppressed by INPP4 B.Gene of phosphate and tension homology deleted on chromsome ten(PTEN)is located on chromosome 10q23.31,which encodes a 403-amino acid protein with phospholipids and proteins.PTEN,as one of the hot tumor suppressor genes in tumor research,plays an important role in regulating cell cycle,inducing cell apoptosis and cell migration and adhesion.The PTEN protein dephosphorylates the D3 site of phosphatidylinositol 3,4,5-triphosphate(PI(3,4,5)P3),which regulates intracellular PI(3,4,5)P3 levels,and the PI3 K / AKT pathway was negatively regulated.In this study,we tested the expression of INPP4 B and PTEN in human glioma and the correlation between them,so as to explore the mechanism of glioma development at the molecular level.At the same time,we hope to provide the theoretical basis for the diagnosis,classification and prognosis of glioma.Methods: 60 cases of glioma tissue samples were collected from the Department of Neurosurgery,Affiliated Hospital of North Sichuan Medical College from January 2015 to August 2016.Including 33 male patients,27 female patients and 31 cases of low grade level of glioma(WHO grade Ⅰ~Ⅱ),25 cases of high grade level of glioma(WHO gradeⅢ~Ⅳ).Pathological diagnosis were made by the pathology department according to WHO(2007)brain tumor classification standard.All the cases have complete medical records and have not received radiotherapy or chemotherapy.In addition,25 normal brain tissue samples were collected as normal controls.The specimens were obtained from the normal brain tissues with high intracranial pressure during traumatic brain injury.All specimens were cut and washed immediately with PBS solution at 4 ℃ to remove blood and necrotic tissue and electrocauterized tissue.The specimen was divided into two parts and one of half was fixed in 4% paraformaldehyde solution for 12 to 24 hours and then paraffin-embedded,the other half was put in liquid nitrogen and transferred to the laboratory and then placed in-80 ℃ refrigerator for use.The expressions of INPP4 B and PTEN in normal brain and glioma were detected by immunohistochemistry(IHC)and real-time quantitative PCR(qRT-PCR).The statistical data were analyzed by SPSS22.0.Results:1 Immunohistochemistry results: The expression of INPP4 B in normal brain tissue group and low grade glioma group and high grade glioma group was significantly different(P<0.05).The positive rate of INPP4 B was 92% in normal brain tissue,67.7% in low grade glioma group and 37.9% in high grade glioma group.The expression of INPP4 B in low grade glioma group was higher than that in high grade glioma group(P<0.05).The expression of INPP4 B in normal brain tissue group was higher than that in low grade glioma group and high grade glioma group(P<0.05).The expression of PTEN in normal brain tissue group and low grade glioma group and high grade glioma group was significantly different(P<0.05).The positive rate of PTEN was 96% in normal brain tissue,74.2% in low grade glioma group and 41.4% in high grade glioma group.The expression of PTEN in low grade glioma group was higher than that in high grade glioma group(P<0.05).The expression of PTEN in normal brain tissue group was higher than that in low grade glioma group and high grade glioma group(P <0.05).2 qRT-PCR results: The expression of INPP4 B mRNA in normal glioma group and low-grade glioma group and high-grade glioma group was statistically significant(P<0.05).The expression level of INPP4 B mRNA in low-grade glioma group was significantly higher than that in low-grade glioma group(P<0.05).The expression of INPP4 B mRNA in high grade glioma group was significantly lower than that in low grade glioma group and normal brain tissue group(P<0.05);the expression of PTEN mRNA in normal brain tissue group and low-grade glioma group and high-grade glioma group was significantly different(P<0.05).The expression of PTEN mRNA in low-grade glioma group was significantly higher than that in low-grade glioma group(P<0.05).The expression of PTEN mRNA in high grade glioma group was significantly lower than that in low grade glioma group and normal brain tissue group(P<0.05);There was a positive correlation between INPP4 B and PTEN in normal brain tissue,low grade glioma and high grade glioma(r = 0.752,P = 0.000).Conclusions:1 The expression level of INPP4 B and PTEN was negatively correlated with the malignant grade of glioma,and decreased with the increase of malignancy of glioma.2 There was a positive correlation between the expression of INPP4 B and PTEN in glioma,which suggests that it may have synergistic effect in inhibiting the occurrence,development,invasion and proliferation of glioma.Further validation requires follow-up experiments.3 Since the expressions of INPP4 B and PTEN both decline in glioma,we hypothesized that combined detection of INPP4 B and PTEN may be used for the diagnosis and prognosis in glioma. |
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