Abstract:

Objective To investigate the expressionof Sirtuin 4 (SIRT4) in colorectal cancer (CRC)cells and tissues and its clinical significance.

Methods  RT-qPCR and Western blot were used to detect the expression of SIRT4 mRNA and protein in normal colorectal epithelial cell, CRC cells, CRC tissues and paired adjacent tissues, respectively. Then, the expression of SIRT4 protein in CRC tissues of 85 cases was investigated by immunohistochemical method, andthe correlation of SIRT4 expression with clinicopathological factors and patients' prognosis were further analyzed.

Results Compared to normal colorectal epithelial cell, the mRNA and protein expression of SIRT4 in CRC cells was significantly decreased(P＜0.05, respectively).Consistently, the mRNA and protein expression of SIRT4 in CRC tissues was significant lower than that of paired adjacent normal tissues(P＜0.05, respectively).Immunohistochemical analysis showed that the low expression of SIRT4 in CRC tissues were significant association with tumor grade, depth of invasion, lymph node metastasis,lympho-vascular invasion, nervous invasion and TNM stage (P＜0.05, respectively), but not with gender, age, tumor site,tumor size andpreoperative CEA level (P>0.05, respectively). Further Kaplan-Meier univariate analysis demonstrated that the low expression of SIRT4 protein was significant related to poor prognosis of CRC patients (P＜0.05).

Conclusion The low expression of SIRT4 in CRC is closely related to the unfavorable clinicopathological factors and poor patients' prognosis, indicating that SIRT4 may become a new biomarker to evaluate the prognosis of CRC.

Key words: colorectal cancer, SIRT4, clinicopathological factors, prognosis