Poly(A)-Specific Ribonuclease (PARN) Promotes the Proliferation, Migration and Metastasis of Esophageal Cancer

Abstract

Background: Esophageal cancer leads to the majority of cancer deaths in the world. Surgery, radiotherapy and chemotherapy are the main treatment methods, but due to its high recurrence and metastasis rate, the overall prognosis is poor. Poly(A)-specific ribonuclease (PARN) is a multifunctional enzyme molecule, which is involved in the occurrence and development of tumors. This study explores the relationship between PARN and the proliferation, metastasis and prognosis of esophageal cancer. Methods: The esophageal cancer tissues and adjacent normal tissues were collected from 91 patients with esophageal cancer after surgery. The expression level of PARN was detected by immunohistochemistry (IHC) using tissue microarray (TMA). PARN expression and its relationships with clinicopathological characteristics and prognosis was detected. In addition, stable PARN knockdown esophageal cancer cell lines TE-1 and Eca-109 were used to study its effect on the phenotype and behavior of tumor cells. Meanwhile, the effect of PARN silencing on tumor growth in vivo was verified by xenotransplantation model in nude mice. Finally, we examined possible downstream signaling mechanisms of PARN in esophageal cancer. Findings: PARN showed high expression in esophageal carcinoma tissues and its expression was significantly correlated with lymphatic metastasis and prognosis of patients. In the culture of PARN knockdown esophageal cancer cell lines, the growth and proliferation were significantly inhibited, and the invasion and migration ability of tumor cells were also significantly decreased. In addition, inhibition of PARN suppressed tumor growth and increased survival time in xenograft murine models. In the PARN knockdown group, BIM, IGFBP-5 and p21 were significantly increased, while the expression levels of anti-apoptotic proteins Survivin and STNF-R1 were significantly down-regulated. In addition, the expression levels of Akt, p-Akt, PIK3CA and CCND1 downstream of the signaling pathway regulating esophageal cancer progression were significantly down-regulated. Interpretation: These results suggest a previously undetected role of PARN as a suppressor of tumor development and its associations of prognosis in esophageal cancer through anti-apoptotic effect. Funding Information: None. Declaration of Interests: The authors declare no conflicts of interests. Ethics Approval Statement: Ethical approval for the study was approved by the Research Ethics Committee of the Second Affiliated Hospital of Guangxi Medical University and Zhujiang Hospital Affiliated to Southern Medical University, and written patient consent was obtained from all patients. Nude mice xenograft model - This study was approved by the Guangxi Medical University Ethics Committee.