Significance And Mechanism Of RanBPM Expression In Osteosarcoma Patients

Background:The malignant tumor of primary bone is a mesenchymal malignant tumor with a low incidence,accounting for less than 0.2% of all malignant tumors.The clinical manifestation of primary malignant tumors of bone is very heterogeneous,and it is necessary to choose appropriate treatment methods.Osteosarcoma(35%),chondrosarcoma(30%)and Ewing sarcoma(16%)are more common primary malignant tumors of bone,of which osteosarcoma is the most common primary malignant tumor of bone.Osteosarcoma mainly occurs in children and young people.Usually located in the extremities: 78% are located in the lower extremities.Since the introduction of neoadjuvant chemotherapy,the survival rate of osteosarcoma has been greatly improved.In the 1980 s of the last century,it has increased from 10%-20% to 50%-60%.The increase in survival rate is due to the combination of multi-drug chemotherapy and advanced surgery.In modern treatment regimens,a combination of doxorubicin and cisplatin is commonly used,with selective addition of methotrexate,ifosfamide,and etoposide.But since 1985,the survival rate of osteosarcoma has not improved substantially.The survival rate of children is 5-10% higher than that of patients under 50 years old,while the survival rate of patients over 60 years old is only 24%.Osteosarcoma cells' poor sensitivity to chemotherapy and drug resistance of chemotherapeutic drugs are the main factors that affect the efficacy of chemotherapy.Therefore,controlling metastasis and overcoming chemotherapy resistance are of great significance for improving the survival rate of osteosarcoma patients.At present,chemotherapeutic drugs are mainly based on DNA damage inducers.The mechanism of action of chemotherapeutic drugs is to induce the expression of cell cycle regulators and apoptosis-related factors in osteosarcoma,leading to cell cycle arrest and apoptosis.Therefore,the related genes that regulate the cell cycle and apoptosis pathway of osteosarcoma have become the key to increase the sensitivity of chemotherapy and control drug resistance to improve the long-term survival rate of patients.Ran BPM is a new Ran protein binding protein.It is widely expressed in different tissues and cell lines and plays the role of scaffold protein in cells.Ran BPM is closely related to the occurrence and development of various tumors.It plays a role of tumor suppressor genes in colon cancer,gastric cancer and lung cancer.Significantly inhibit tumor metastasis and increase its sensitivity to chemotherapy drugs.However,the role of Ran BPM in the development of osteosarcoma is still unclear.Some studies have found that Ran BPM is lowly expressed in osteosarcoma cells and is related to the proliferation,apoptosis and metastasis of osteosarcoma.Ran BPM is a scaffold protein related to apoptosis,and the distribution in cells can change significantly with the progress of apoptosis.Recent studies have shown that Ran BPM can play an important regulatory role in the form of apoptotic precursor protein in apoptosis,but its role and molecular mechanism in the process of osteosarcoma apoptosis still need to be further studied.Therefore,this study detected the expression of Ran BPM in osteosarcoma tissues,analyzed its clinicopathological significance,and overexpressed Ran BPM to preliminary explore its effect on osteosarcoma cell apoptosis and molecular mechanism.Purpose:To study the clinical significance of Ran BPM expression in osteosarcoma patients' tissues,and to preliminary explore the molecular mechanism of its influence on osteosarcoma cell apoptosis.Method:Collect the second affiliated hospital of Chongqing Medical University(from January 2014 to December 2019)and the second affiliated hospital of Army Military Medical University(August 2008 to December 2014)with osteosarcoma patients with more complete cases and follow-up data A total of 54 clinical samples were included in this study.The expression of Ran BPM in human osteosarcoma tissue samples was detected by immunohistochemistry,and its clinical pathological significance was analyzed.The m RNA and protein expression of Ran BPM in osteoblasts and different osteosarcoma cell lines were detected by RTPCR and Western blot.Lentivirus was used to establish a model of Sa OS2 osteosarcoma cell line that stably overexpressed Ran BPM,and flow cytometry and TUNEL staining were used to detect the apoptosis rate of osteosarcoma cells in the overexpressed Ran BPM group and the control group.The mitochondrial membrane potential was used to detect the overexpressed Ran BPM group and In the control group,the mitochondrial transmembrane potential changes during apoptosis.The result:1.Of the 54 cases of osteosarcoma paraffin specimens,43 cases had positive expression of Ran BPM,and the positive expression rate was 79.63%.The expression rate of osteoblastoma tissues in the control group was 100%,P<0.05,the difference was statistically significant.2.Comparison between the groups found that the expression of Ran BPM was not related to the clinical and pathological parameters of patients with osteosarcoma,such as gender,age and pathological classification,and the difference was not statistically significant(P>0.05).3.The expression of Ran BPM in osteosarcoma tissue is related to osteosarcoma staging,tumor recurrence and lung metastasis.In advanced,recurrent or metastatic osteosarcoma tissue,the positive rate of Ran BPM is relatively low(P<0.01 and P<0.001 respectively).4.Ran BPM was positively expressed in osteoblasts and osteosarcoma cell lines,and its expression in osteoblasts was significantly higher than that of osteosarcoma cells(P<0.05),and in osteosarcoma cell lines MG63 and The expression in HOS is higher than that of the cell lines Sa OS2 and U2 OS with higher malignant degree(P<0.05).5.Overexpression of Ran BPM reduced the proliferation of osteosarcoma cells and promoted the increase of apoptosis rate(P<0.05).Overexpression of Ran BPM significantly increased the expression levels of caspase-3 and Cytc,and at the same time the ratio of Bax:Bcl-2 was increased(P<0.05);overexpression of Ran BPM destroyed the mitochondrial membrane potential and induced the endogenous mitochondrial apoptosis signal transduction Guide way.Conclusions:1.The expression of Ran BPM in osteosarcoma tissue is related to osteosarcoma stage,tumor recurrence and lung metastasis.In the late,relapsed or metastatic osteosarcoma tissue,the positive rate of Ran BPM is relatively low.2.The apoptosis rate of osteosarcoma cells over-expressing Ran BPM is increased.Ran BPM may play a role in inducing apoptosis of osteosarcoma cells by up-regulating the endogenous mitochondrial pathway.