Overexpression of aminoacylase 1 is associated with colorectal cancer progression.

Aminoacylase 1 (ACY1) is a cytosolic enzyme responsible for amino acid deacylation during intracellular protein degradation. ACY1 has been implicated in a number of human tumor types. However, the exact role of ACY1 in tumor development remains elusive because it was found to be lost in small cell lung cancer and renal cell carcinoma but overexpressed in colorectal cancer (CRC). The present study aims to further clarify the relationship of ACY1 with CRC progression. Immunohistochemical staining was performed in tissue microarrays composed of 120 cases of CRC using a monoclonal anti-ACY1 antibody. Immunoreactivity was analyzed in association with patients' clinicopathologic parameters and survival time. The role of ACY1 in cell proliferation and apoptosis was assessed by silencing its expression in HCT116 cells using a small interfering RNA. Strong expression of ACY1 was found to be significantly associated with more advanced TNM stage, lymph node metastasis, positive vascular invasion, and shorter cancer-specific survival. ACY1 knockdown significantly inhibited cell proliferation and induced apoptosis. We concluded that ACY1 expression in CRC varies with stage and appears to play a role in cell proliferation and apoptosis. Further evaluation of ACY1 as a clinically useful prognostic marker and a potential drug target for CRC would seem worthwhile.