Effect Of Tumor Suppressor Gene PTEN On Proliferation, Invasion And Migration Of Human Thyroid Papillary Carcinoma Cell Line

BackgroundThe Phosphatase gene and tensin homolog deleted on chromosome ten(PTEN gene)is a tumor suppressor gene newly discovered by the research team of Li et al.in 1997.The gene is located at 10q23.3 of human chromosome point.The protein expressed by PTEN gene consists of 403 amino acids.It is found that PTEN protein not only has lipid phosphatase activity,but also has protein phosphatase activity,so PTEN is the first double phosphatase activity found so far.Tumor suppressor gene.The discovery of PTEN has caused great reaction in the field of oncology.It has once become a new star in the field of oncology,and its research reports have continued.Low expression of the PTEN gene has been found in many tumors,Such as colorectal cancer,thyroid cancer and so on.Thyroid carcinoma(TC)is the most common endocrine malignancy and one of the most common malignant tumors in the head and neck.Studies have shown that thyroid cancer can account for 5.11% of the total number of malignant tumors of the head and neck,accounting for 0.22% to 1.0% of the total number of malignant tumors.According to tissue-derived thyroid cancer,it can be divided into three types: differentiated thyroid cancer,medullary thyroid carcinoma,and thyroid undifferentiated carcinoma.Among them,differentiated thyroid cancer is the most common type,and differentiated thyroid cancer has the most thyroid papillary type,it accounts for 85% of all thyroid malignancies.According to the latest epidemiological survey,the incidence of thyroid cancer,especially papillary thyroid carcinoma,continues to increase in recent years.The clinical features of papillary thyroid carcinoma are: low malignancy,slow growth,and lack of specificity in clinical manifestations.The current diagnosis relies mainly on high-resolution ultrasound and rapid frozen pathology.Because the early clinical manifestations of patients often have no obvious symptoms,many patients have found distant metastasis of cancer during surgical treatment,which seriously affects the prognosis of patients.Therefore,how to treat patients with papillary thyroid carcinoma more effectively,to define the internal mechanism of the development and metastasis of papillary thyroid carcinoma,to find new targets for the invasion and migration of papillary thyroid carcinoma,and to become a problem in the current diagnosis and treatment of thyroid papillary carcinoma.As a star molecule in the newly discovered tumor suppressor gene family,the tumor suppressor gene PTEN must play an indispensable role in the diagnosis and treatment of tumor diseases in the future.At present,most studies on papillary thyroid carcinoma and PTEN gene are used to observe the expression of PTEN protein in postoperative resected specimens of patients with cancer,numerous studies have supported the formation and development of thyroid cancer and the low expression of PTEN gene,but there are few reports on the specific biological behavior of PTEN gene on the level of thyroid papillary cancer cells.The aim of this study was to observe the effect of PTEN gene expression on the biological behavior of human thyroid papillary carcinoma cells,and further validate the relationship between PTEN gene and papillary thyroid carcinoma,and to find new targets for invasion and migration of papillary thyroid carcinoma.It provides a theoretical basis for better diagnosis and treatment of thyroid papillary carcinoma.ObjectiveThis study was to observe the effect of PTEN gene expression on the biological behavior of human thyroid papillary carcinoma cell line proliferation,invasion and migration.Methods1.The experimental material TPC-1 cell line was presented by Professor Zheng Lili from the Department of Endocrinology,the First Affiliated Hospital of Zhengzhou University.The experimental place was the key laboratory of the First Affiliated Hospital of Zhengzhou University.The overall method was: transfection of PTEN overexpression vector(pBP-PTEN)in human TPC-1 cell line,and transfection of empty vector(pBP)as control.After incubation in cell culture,western-blot method was used to detect PTEN in human TPC.the effect of PTEN on cell proliferation of TPC-1 cell line was observed by measuring the absorbance A value in the thiazolyl blue colorimetric(MTT)assay,transwell chamber to observe the effect of PTEN on cell invasion and migration of TPC-1 cell line by detecting the number of cells,the collected values are expressed as mean ± standard deviation(Mean ± SD),and t test is applied.2.TPC-1 cell culture and transfection(1)The PTEN overexpression vector(pBP-PTEN)was constructed and maintained by the Zhengzhou University Laboratory.(2)When the TPC-1 cells were cultured to 80% confluency according to cell culture requirements,the PTEN overexpression vector(pBP-PTEN)and the PTEN-free control vector(pBP)were transfected into TPC-1 cells.Expression group and control vector group.Transfection reagent with Lipofectamine 2000.3.Analysis of the effect of PTEN gene expression on the biological behavior of human thyroid papillary carcinoma cell lines(1)Western-blot assay for expression of PTEN in human TPC-1 cell line.(2)The effect of PTEN on cell proliferation of TPC-1 cell line was detected by thiazolyl blue colorimetry(MTT)assay.(3)Transwell chamber detects PTEN cell invasion of TPC-1 cell line.(4)Transwell chamber detects PTEN cell migration in TPC-1 cell line.Results1.The western-blot test showed that the PTEN protein level in the overexpression group was significantly higher than that in the control group,indicating that TPC-1 cells overexpressing PTEN were successfully constructed.2.The results of MTT assay showed that the absorbance A value of the overexpression vector group was 0.40±0.02,which was significantly lower than the absorbance A value of the control group of 0.75±0.03(P<0.05).This indicates that PTEN inhibits the proliferation of TPC-1 cells.3.The number of cell invasion in the overexpression vector group was 45.76±4.11,which was significantly lower than that in the control group,95.32±5.41(P<0.05).It indicated that PTEN significantly inhibited the invasion ability of TPC-1 cells.4.The number of cell migration in the overexpression vector group was 25.62±2.89,which was significantly lower than that in the control group,which was 53.47±4.42(P<0.05).It indicated that PTEN significantly inhibited the migration ability of TPC-1 cells.ConclusionOverexpression of PTEN can significantly inhibit the proliferation,invasion and migration of thyroid papillary carcinoma cells,suggesting that PTEN gene may be a potential target for the treatment of invasion and migration of papillary thyroid carcinoma,with high clinical value.