Proto-oncogene Wip1, a member of a new family of proliferative genes in NSCLC and its clinical significance

This study aimed to analyze the expression, clinical significance of proto-oncogene in non small cell lung cancer (NSCLC), and the biological effect in its cell line by siRNA targeting wild-type p53-induced phosphatase 1 (Wip1). Immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) were, respectively, used to analyze Wip1 protein expression in 75 cases of NSCLC and normal tissues to study the relationship between Wip1 expression and clinical parameters. Wip1 siRNA was transiently transfected into papillary NSCLC H1299 cell by liposome-mediated method and was detected by RT-PCR and Western blot. MTT assay, cell apoptosis, and cell cycle were also conducted as to the influence of the downregulated expression of Wip1 that might be found on H1299 cells biological effect. The positive rates of Wip1 protein was 69.3 % in NSCLC tissues but 16.0 % expressed in normal tissues (P < 0.05). The relative content of Wip1 mRNA was 0.785 +/- 0.062 and 0.147 +/- 0.020 in NSCLC tissues and normal tissues, respectively, with significant differences between the two types (P < 0.05). There were no significant differences between Wip1 expression and sex, age, tumor size, and pathological types (P > 0.05). However, there were significant differences between Wip1 expression and lymph node metastasis, clinical stages, and tumor differentiation (P < 0.05). Individuals with positive and negative levels of Wip1 expression showed were statistically significant differences in the 5-year overall survival rate (P < 0.05). RT-PCR and Western blot showed that H1299 cell transfected Wip1 siRNA had a lower relative expressive content than normal cell (P < 0.05). MTT assay, cell apoptosis, and cell cycles demonstrated that H1299 cell transfected Wip1 siRNA had a lower survival fraction, higher cell apoptosis, more percentage of the G0/G1 phases, and lower cells in the S phases (P < 0.05). Wip1 protein and mRNA were increased in NSCLC, specifically in lymph node metastasis, clinical stages, and tumor differentiation. Wip1 may be involved in the biological processes of NSCLC cell proliferation, cell apoptosis, and cell cycle.