Objective:The present study aims to evaluate the chemopreventive effect of celecoxib combined with tamoxifen on breast tumor induced by methylnitrosourea (MNU) in rats. Methods:A total of 140 SD female rats were injected with MNU to estab-lish breast tumor models. The rats were divided subsequently into control, celecoxib, tamoxifen, and combination groups. The occur-rence rates, volumes of breast tumor, and expression levels of cyclooxygenase 2 (COX-2) and c-erbB-2 were observed. Results:The tu-mor occurrence rates were lower in the celecoxib and tamoxifen groups than in the control group. The combination group exhibited the lowest tumor-occurrence rate. The tumor volumes of the celecoxib and tamoxifen groups were lower than that of the control group. The combination group had the least tumor volume. The positive rates of COX-2 and c-erbB-2 in the celecoxib and combination groups were lower than those in the control and tamoxifen groups (P<0.05). Conclusion:The combination of celecoxib and tamoxifen can sig-nificantly suppress MNU-induced breast tumor in female rats.

Objective The aim of this study was to investigate the role of long chain non-coding RNA LINC-PINT in drug sensitivity of hypoxia induced in head and neck squamous cell carcinoma(HNSCC)through the Hippo/Yes-associated protein(YAP)signaling pathway.Methods The proliferative changes of HNSCC cell lines(AGZY-973 cells,HN4 cells,and HN30 cells)and nor-mal human oral keratinocytes(NHOKs)in hypoxic environment were detected by CCK-8 assay;HN30 cells in good condition were taken and set them as the normal group,hypoxia group,hypoxia+LINC-PINT overexpression group,and hypoxia+overexpression negative control group.The expression of LINC-PINT in HN30 cells was detected by qRT-PCR;CCK-8 assay was applied to de-tect the drug sensitivity of HN30 cells,and the effect of cisplatin on proliferation in HN30 cells;cell apoptosis was detected by flow cy-tometry;and Western blot was applied to detect the expression of hypoxia inducible factor-1α(HIF-1α),p-YAP,and YAP protein in HN30 cells.Results Under hypoxia conditions,the proliferative rates of AGZY-973 cells,HN4 cells and HN30 cells were obvi-ously higher than that of NHOKs cells(P＜0.05).Compared with the normal group,the IC50 value,the expression of HIF-1 α and p-YAP/YAP in the hypoxic group were obviously increased in HN30 cells,the rate of apoptosis,the rates of cell growth inhibition at 24 h and 48 h,and the expression of LINC-PINT protein were obviously decreased(P＜0.05);Compared with the hypoxia+overex-pression negative control group,the IC50 values,the expression of HIF-1α and p-YAP/YAP cells in the hypoxia overexpression of LINC-PINT group was obviously reduced in HN30,the rates of apoptosis,the rates of cell growth inhibition at 24 h and 48 h,and the expression of LINC-PINT protein were significantly increased(P＜0.05).Conclusion Overexpression of LINC-PINT can en-hance the hypoxia-induced cisplatin sensitivity in HNSCC,which may be related to the inhibition of the activation of Hippo/YAP sig-naling pathway.