lncRNA Erbb4‑IR is downregulated in prostate carcinoma and predicts prognosis

Long non-coding (lnc) RNA Erbb4-IR has been associated with diabetic renal injury; however, its roles in other diseases remain unknown. Therefore, the present study investigated the involvement of Erbb4-IR in prostate carcinoma. Reverse transcription-quantitative PCR was used to analyze gene expression in tissue samples collected from patients with prostate carcinoma. Overexpression experiments via cell transfection were performed to determine the association between Erbb4-IR and microRNA (miR)-21. Furthermore, Cell Counting Kit-8 and cell apoptosis assays were performed to assess cell proliferation and apoptotic rate, respectively. The results revealed that Erbb4-IR was downregulated in prostate carcinoma tissues compared with adjacent non-cancerous tissues, and that low expression of Erbb4-IR in tumor tissues was closely associated with poor survival. Furthermore, miR-21 was upregulated in prostate carcinoma tissues compared with adjacent non-cancerous tissues and was inversely associated with Erbb4-IR expression in tumor tissues. In vitro cell experiments revealed that Erbb4-IR overexpression resulted in the downregulation of miR-21, while miR-21 overexpression did not significantly affect the expression of Erbb4-IR. Moreover, Erbb4-IR overexpression increased apoptosis and inhibited the proliferation of prostate carcinoma cells. miR-21 overexpression resulted in the opposite effect and attenuated the effects of Erbb4-IR overexpression. Therefore, the results of the present study suggested that lncRNA Erbb4-IR is downregulated in prostate carcinoma and may inhibit cancer development by downregulating miR-21.