Expression and Role of Oct3/4 in Injury-Repair Process of Rat Alveolar Epithelium after 5-Fu Treatment.

OBJECTIVE: We aimed to investigate how the embryonic stem cell-related gene Oct3/4 changes during the injury-repair process of distal pulmonary epithelium induced by 5-fluorouracil (5-Fu). METHODS: We have developed the lung injury model induced by 5-Fu and observed the dynamic changes of Oct3/4 by indirect immunofluorescence, Western blot, and quantitative real-time PCR. Immunofluorescence double staining was used to compare the positions of Oct3/4(+) cells and other reported alveolar epithelial stem cells. RESULTS: Oct3/4(+) cells were not found in normal rat lung epithelial cells. However, after treatment with 5-Fu, Oct3/4(+) cells appeared at 12 h, reached the peak at 24 h, then decreased at 48 h, and eventually disappeared at 72 h. Oct3/4 was localized in the nucleus. We found that the sites of Clara cell secretory protein and surfactant protein-C dual positive cells were apparently different from Oct3/4(+) cells. CONCLUSIONS: Our results revealed that, in rat alveolar epithelium, expression of Oct3/4 could be induced after treatment with 5-Fu, then decreased gradually, and was silenced following the alveolar epithelial differentiation. We hold that Oct3/4(+) cells are lung stem cells, which can provide new evidence for identification and isolation of lung epithelial stem cells.

Downregulation of KPNA2 in non-small-cell lung cancer is associated with Oct4 expression.

BACKGROUND: Oct4 is a major transcription factor related to stem cell self-renewal and differentiation. To fulfill its functions, it must be able to enter the nucleus and remain there to affect transcription. KPNA2, a member of the karyopherin family, plays a central role in nucleocytoplasmic transport. The objective of the current study was to examine the association between Oct4 and KPNA2 expression levels with regard to both the clinicopathological characteristics and prognoses of patients with non-small-cell lung cancer (NSCLC). METHODS: Immunohistochemistry was used to detect the expression profile of Oct4 and KPNA2 in NSCLC tissues and adjacent noncancerous lung tissues. Real-time polymerase chain reaction and western blotting were used to detect the mRNA and protein expression profiles of Oct4 and KPNA2 in lung cancer cell lines. Small interfering RNAs were used to deplete Oct4 and KPNA2 expressions. Double immunofluorescence was used to detect Oct4 expression in KPNA2 knockdown cells. Co-immunoprecipitation was used to detect the interaction of Oct4 and KPNA2. RESULTS: Oct4 was overexpressed in 29 of 102 (28.4%) human lung cancer samples and correlated with differentiation (P = 0.002) and TNM stage (P = 0.003). KPNA2 was overexpressed in 56 of 102 (54.9%) human lung cancer samples and correlated with histology (P = 0.001) and differentiation (P = 0.045). Importantly, Oct4 and KPNA2 expression levels correlated significantly (P < 0.01). Expression of Oct4 and KPNA2 was associated with short overall survival. In addition, depleting Oct4 and KPNA2 expression using small interfering RNAs inhibited proliferation in lung cancer cell lines. Real-time polymerase chain reaction and western blotting analysis indicated that reduction of KPNA2 expression significantly reduced mRNA and nucleoprotein levels of Oct4. Double immunofluorescence analysis revealed that nuclear Oct4 signals were reduced significantly in KPNA2 knockdown cells. Co-immunoprecipitation experiments revealed that KPNA2 interacts with Oct4 in lung cancer cell lines. CONCLUSION: Oct4 and KPNA2 play an important role in NSCLC progression. Oct4 nuclear localization may be mediated by its interaction with KPNA2.

[The inhibitive effect of COX-2 inhibitor NS-398 on cancer cell growth of human tongue squamous cell carcinoma].

PURPOSE: To investigate the inhibitive effect of COX-2 inhibitor NS-398 on cancer cell growth of human tongue squamous cell carcinoma. METHODS: MTT assay was used to study the inhibitive effect of NS-398 on the growth of Tca8113 cells, and to investigate the time-effect relationship and dose-effect relationship between NS-398 and Tca8113 cells. The effect of NS-398 on cell cycle changes of Tca8113 was studied by flow cytometry (FCM). The statistical date were analysed by SAS 8.1 software. Student's t test and repeated-measure ANOVA were used to analyze the date. RESULTS: The Tca8113 cell culture median contained 0, 25, 50, 75, 100, 125, 150, 200 micromol/L NS-398, and individually cultured for 48, 72, 96, 120 hours. The inhibitive effect increased with the time prolonging and the concentration increasing. The effect was most obvious with 150 micromol/L NS-398 cultured for 96 hours (concentration: P<0.05, time: P<0.001). NS-398 can cause great increase of Tca8113 cells in G0/G1 phase, while cells in G2/M phase decreased, and cells arrested in G0/G1 phase (P<0.001). CONCLUSION: NS-398 can inhibit the growth of Tca8113 cells. The inhibitive effect of NS-398 on Tca8113 cells is dose-dependent and time-dependent, and this effect may be related to the inhibition of cell circle growth. NS-398 may play an important role in the treatment of oral squamous cell carcinoma.