Preliminary Researches On The Effect Of MRPL35 Protein On Human Esophageal Cancer Cells Growth

Background:With the rapid development of modern medicine,the life span of human beings is gradually prolonged.The problem of threatening human health has rapidly shifted from tuberculosis,organic heart disease and diabetes mellitus,which were put forward by Western medical circles at the beginning of this century,to cancer.Esophageal cancer is one of the common malignant tumors of digestive tract.It has poor prognosis and high mortality.According to statistics,in 2018,there were 57 200 new cases and 509 000 deaths.Morbidity and total mortality ranked seventh and sixth respectively.More than 95% of the pathological types of esophageal cancer are squamous cell carcinoma and adenocarcinoma.Significant risk factors for squamous cell carcinoma include smoking,alcohol consumption and achalasia,and are predominant in non-industrialized countries.The major risk factors for adenocarcinoma include chronic gastroesophageal reflux disease,obesity and smoking,which are predominant in developed countries.Esophageal cancer usually has no obvious symptoms in the early stage.If dysphagia occurs or accompanied by weight loss without obvious cause,the initial diagnosis is usually made by endoscopy.After the diagnosis of cancer,the depth of the tumor was determined by endoscopic ultrasonography and lymph node involvement was assessed.The distant metastasis was excluded by computed tomography,and the initial stage was defined.Local non-spread tumors can be treated by endoscopic mucosal resection,while local tumors with or without intraregional lymph node metastasis can be treated by esophagectomy,neoadjuvant chemotherapy,radiotherapy and chemotherapy or combination therapy.Palliative interventional therapy is used for unresectable or distant metastatic tumors.At present,there is no definite strategy for prevention andearly screening of esophageal cancer.Mitochondrial ribosomal protein 35(MRPL35),a member of the mitochondrial ribosomal proteins(MRPs)family,is involved in coding the large 39 s subunit of mitochondrial ribosome.Relevant studies have shown that MRPL35 plays an important role in the synthesis of cytochrome c oxidase.At the same time,in vitro experiments have confirmed that it is involved in regulating the proliferation,apoptosis and cycle of rectal cancer cells,but little research has been done on the growth effect and mechanism of esophageal cancer cells.Objective:To study the effect of MRPL35 protein on the growth of human esophageal cancer cells Methods:To analyze the expression of MRPL35 m RNA and protein in 20 pairs of esophageal cancer patients and adjacent normal tissuesd.Two kinds of human esophageal cancer cells were preliminarily screened and the expression level of MRPL35 in knockout cells was reduced by lentivirus transfection.Western Blot and Real-time PCR were used to test gene knockout efficiency.The effects of MRPL35 on the proliferation of two kinds of esophageal cancer cells were observed by CCK8 assay and plate cloning assay.The effects of MRPL35 on the apoptosis and cycle of two kinds of esophageal cancer cells were detected by flow cytometry.Western Blot method was used to detect the changes of apoptotic proteins such as c-caspase 3,c-PARP,Bcl-2 and bax.Results:1.Western blotting and PCR results indicated that the expression of MRPL35 in esophageal cancer tissues was higher than that in adjacent normal tissues.2.MRPL35 was expressed in all four kinds of esophageal cancer cells,and the expression abundance was higher,but there was no significant difference in the expression levels of MRPL35 m RNA among the four kinds of cells.3.When MRPL35 was knocked down by lentivirus transfection,the proliferation rate of KYSE410 and TE-1 cells decreased,the apoptotic rate increased,and the cellcycle was blocked in G2/M phase.4.The results of western blotting showed that the expression of apoptotic related proteins c-caspase 3 and c-PARP increased,while the expression of apoptotic Bcl-2protein decreased and the expression of apoptotic Bax protein increased after lentivirus transfection knocked down MRPL35.Conclusion:MRPL35 promotes the proliferation of esophageal cancer cells.Silencing MRPL35 gene can promote apoptosis and induce cycle arrest.The related mechanisms need to be further studied.