Livin is a novel member of the inhibitor of apoptosis protein family, which has been identified to be expressed in various malignancies and is suggested to be associated with poor prognostic significance. However, no data are available concerning the significance of livin in mid-distal rectal cancer. In the present study, livin expression, and its association with clinicopathological characteristics and prognosis was examined in patients with mid-distal rectal cancer. Apoptotic susceptibility, invasion capacity and chemosensitivity of LoVo cells were investigated using small interfering RNA (siRNA)-mediated knockdown of livin. It was revealed that livin was highly expressed in mid-distal rectal cancer tissues compared with the normal rectal mucosal tissues. Livin expression was associated with pathological grade, extent of invasion (T stage) and extent of lymph node metastasis (N stage) of tumor, contributing to poor prognosis of mid-distal rectal cancer following surgery. The data suggest that aggressive surgery should be applied in patients with mid-distal rectal cancer with high expression of livin. It was also revealed that knockdown of livin by siRNA increased the apoptotic rate, suppressed invasion of LoVo cells, and decreased the half-maximal inhibitory concentration of oxaliplatin and 5-fluorouracil by ~50% in LoVo cells significantly compared with control groups. The data suggested that a combination of downregulation of livin and anticancer drugs may significantly decrease the toxicity of anticancer drugs. Taken together, the present study indicated that livin may be a promising target in clinical therapy of mid-distal rectal cancer.
Keywords: apoptosis; chemosensitivity; invasion; livin; mid-distal rectal cancer; prognosis.