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Objective:To study the expression and interaction between miR-194 and PTPN12 in the process of age-related atrophy of thymus for clarifying the regulatory mechanism in the process of this disease.Methods:C57BL/6 mouse were divided into 4 groups as 1 month,6 months,10 months and 19 months old and each group has 6 cases.Thymus tissue was removed and thymic stromal cells were isolated.And thymus epithelial cells were washed out by CD45 antibody and LS column after anesthesia.Fluorescence quantitative real-time PCR and Western blot were used to detect the changes of miR-194 and PTPN12 gene expression in thymus epithelial cells with aging.miR-194 and PTPN12 luciferase reporter vectors were transfected into HEK293 cells,and the auto fluorescence values were detected at 24 h and 48 h,respectively in vitro.Results:The expression level of miR-194 decreased (P<0.05),while the expression level of PTPN12 mRNA increased (P<0.05) as the age increased.And the correlation between miR-194 and PTPN12 mRNA expression was found to be negative(P<0.05).In vitro,luciferase reporter gene results show that miR-194 has a direct effect on the 3'UTR region of PTPN12 gene and had the highest binding efficiency in 48 h.Conclusion:PTPN12 is one of the target genes of miR-194,which is involved in the aging process of thymus and is an important factor regulating the function of thymic ep-ithelial cells.
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Objective To investigate the expression of non receptor protein tyrosine phosphatase 12 (PTPN12) in hepatocellular carcinoma (HCC) and its adjacent tissues and investigate the relationship between the expression of non receptor protein and prognosis of hepatocellular carcinoma (HCC).Methods The expresson of PTPN12 protein in HCC tissues and adjacent liver tissues was detected by immunohistochemistry.The relationship between the expression of PTPN12 protein and prognosis of primary hepatocellular carcinoma was evaluated by rank correlation and Cox proportional hazards regression model.Results Compared with the adjacent liver tissues,the expression of PTPN12 protein in HCC tissues was significantly lower (55.83％ vs 43.12％,P＜0.005).Further analysis showed that the decreased expression of PTPN12 was closely related with tumor recurrence (x2 =4.346,P=0.015).Single factor analysis showed that the decreased expression of PTPN12 in hepatocellular carcinoma and liver cancer specific survival and recurrence of hepatocellular carcinoma related (x2=5.687,P＜0.001),and multivariate Cox proportional hazards regression model analysis showed that the expression of PTPN12 in patients with liver cancer were independent prognostic factors (x2 =6.687,P＜0.05).Conclusion The expression of PTPN12 protein was down or absent in human hepatocellular carcinoma,and the expression of PTPN12 may be a biomarker for the recurrence and prognosis of HCC patients.
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Objective: To identify the relationship between the expression of protein tyrosine phosphatase non-receptor type 12 (PTPN12) and radiotherapy effect in non-small cell lung cancer (NSCLC) tissues and to determine whether PTPN12 deficiency can sensi-tize lung cancer cells to irradiation. Methods: From September 2013 to October 2014, 92 NSCLC patients undergoing radiotherapy with or without platinum-based combination chemotherapy were analyzed retrospectively. Before the treatment, PTPN12 expression was detected through immunohistochemistry. After the completion of radiotherapy, the patients' responses were assessed and radio-therapeutic efficacy analyzed. The human NSCLC cell line H1299 was infected with shPTPN12 knockdown, and colony survival assay was analyzed after irradiation. Chi-square test was used to examine the correlation between PTPN12 expression and clinicopathologi-cal characteristics. Univariate analyses and Logistic regression test were used to analyze the relationship between clinicopathological characteristics and radiotherapeutic response. Results: Patients with low PTPN12 expression were more sensitive to radiotherapy than those with high PTPN12 expression (80.0%vs. 57.1%, P=0.018). Multivariate analysis showed that PTPN12 expression was the on-ly independent predictor of radiotherapeutic response in NSCLC. The H1299-shPTPN12-knockdown cells were sensitive to irradiation. Conclusions:The results of the study indicated that downregulation of PTPN12 improved the radiosensitivity of NSCLC cells.
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Protein tyrosine phosphatase non-receptor type 12 (PTPN12) is a recently identified tumor suppressor gene (TSG) that is frequently compromised in human triple-negative breast cancer. In the present study, we investigated the expression of PTPN12 protein by patients with breast cancer in a Chinese population and the relationship between PTPN12 expression levels and patient clinicopathological features and prognosis. Additionally, we explored the underlying down-regulation mechanism from the perspective of an epigenetic alteration. We examined PTPN12 mRNA expression in five breast cancer cell lines using semi-quantitative reverse-transcription PCR, and detected PTPN12 protein expression using immunohistochemistry in 150 primary invasive breast cancer cases and paired adjacent non-tumor tissues. Methylation-specific PCR was performed to analyze the promoter CpG island methylation status of PTPN12. PTPN12 was significantly down-regulated in breast cancer cases (48/150) compared to adjacent noncancerous tissues (17/150; P < 0.05). Furthermore, low expression of PTPN12 showed a significant positive correlation with tumor size (P = 0.047), lymph node metastasis (P = 0.001), distant metastasis (P = 0.009), histological grade (P = 0.012), and survival time (P = 0.019). Additionally, promoter CpG island hypermethylation occurs more frequently in breast cancer cases and breast cancer cell lines with low PTPN12 expression. Our findings suggest that PTPN12 is potentially a methylation-silenced TSG for breast cancer that may play an important role in breast carcinogenesis and could potentially serve as an independent prognostic factor for invasive breast cancer patients.