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Effects of long intergenic non-coding RNA (lincRNA)-p21 on the proliferation, migration and invasion ability of HepG2 liver cancer cells were assessed to explore the underlying mechanism. The lincRNA-p21 small interfering RNA (siRNA) lentivirus vector was constructed, transfected and screened to obtain a stable cell line, which constituted the experimental group. At the same time, the empty virus vector was transfected as the control group. The messenger RNA (mRNA) expression of lincRNA-p21 in cells was detected via reverse transcription-polymerase chain reaction (RT-PCR). The proliferation ability of cells was detected via Cell Counting kit-8 (CCK-8) assay. Transwell chamber experiment was used to observe cell migration and invasion ability. Compared with that in the control group, the mRNA expression level of lincRNA-p21 in cells in the experimental group was obviously decreased (p<0.05). Results of CCK-8 showed that the proliferation ability of liver cancer cells was remarkably higher than that in the control group after knockout of lincRNA-p21 (p<0.05). Results of the Transwell chamber experiment revealed that the invasion and migration ability of HepG2 cells in experimental group was markedly higher than that in control group (p<0.05). When lincRNA-p21 was inhibited, the proliferation, invasion and migration ability of HepG2 cells were significantly enhanced, and the apoptosis rate was significantly decreased. Thus, lincRNA-p21 on the surface may play an inhibitory role in the occurrence, development and metastasis of liver cancer. [ABSTRACT FROM AUTHOR]

Abstract: Patients with advanced hepatocellular carcinoma (HCC) have shown to benefit from tamoxifen treatment. The mechanisms of tamoxifen effects in HCC, however, are not yet clearly understood. The PI3K/Akt/mTOR signal pathway is involved in cell proliferation, tumorigenesis, and apoptosis. Over-expression of survivin has played an important role in leading to antiapoptosis. The current study investigated changes in mTOR pathway and survivin expression in hepatocarcinoma cell line HepG2 treated with tamoxifen. We detected apoptosis of hepatocarcinoma cells by flow cytometry assay. Survivin transcription level and p70S6k was demonstrated by PCR, dual-luciferase reporter assay and western blot analysis respectively. Our results are showed as follows: tamoxifen leads to apoptosis of the cells, and reduction in survivin expression, as well as a dramatic reduction in the activated form of p70S6 kinase. Twenty micromoles tamoxifen treatment signifcantly depresses transcription of survivin mRNA. Treating HepG2 cells with rapamycin, a specific mTOR inhibitor, significantly reduce survivin protein level but did not affect survivin transcription, which indicated that tamoxifen and rapamycin were synergistic in regards to down-regulation of survivin expression in hepatocellular carcinoma cells. Our results suggest that tamoxifen down-regulate survivin expression in HepG2 cells is mediated by transcriptional and posttranscriptional level via PI3K/Akt/mTOR pathway to induce apoptosis. [Copyright &y& Elsevier]

Abstract: Objective: We sought to determine whether paeoniflorin enhances 5-fluorouracil-induced apoptosis in human gastric carcinoma cells, and, if so, to determine the relationship between this apoptosis and NF-κB activation. Methods: Paeoniflorin was diluted to different concentrations and added to gastric carcinoma cells (SGC-7901) at different times. Western blot was used to test the expression of NF-κB in nuclear and IκBα, p-IκBα, IKKα in cytoplasm. Further, the intranuclear expression of NF-κB was confirmed by ELISA assay. The impact of paeoniflorin and 5-fluorouracil on cell apoptosis of gastric carcinoma cells was estimated by flow cytometry. Results: Paeoniflorin revealed dramatic inhibition of NF-κB activity in the nuclei of the cells. The inhibition pattern of NF-κB was exhibited in a time- and dose-dependent manner, which was confirmed by Western blot and ELISA. Decreased nuclear translocation of NF-κB induced by paeoniflorin was found by preventing IκBα phosphorylation. Moreover, 5-fluorouracil-induced cell apoptosis was promoted by paeoniflorin in gastric carcinoma cells. Conclusions: Paeoniflorin can inhibit NF-κB activity of SGC-7901 cells, and enhance 5-fluorouracil-induced apoptosis of gastric carcinoma cells. [Copyright &y& Elsevier]

Purpose: MicroRNAs (miRNAs) are short non-coding RNA molecules, which post-transcriptionally regulate genes expression and play crucial roles in diverse biological processes. Recent studies have shown that dysregulation of miRNAs might modulate the resistance of cancer cells to anti-cancer drugs, yet the modulation mechanism is not fully understood. We aimed to investigate the possible role of miRNAs in the development of multidrug resistance (MDR) in human gastric and lung cancer cell lines. Methods: miRNA Quantitative real-time PCR was used to detect the different miRNA expression levels between drug resistant and parental cancer cells. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to test the drug-resistant phenotype changes in cancer cells via over or downregulation of miRNAs. Dual-luciferase activity assay was used to verify the target genes of miRNAs. Western blot analysis and apoptosis assay were used to elucidate the mechanism of miRNAs on modulating drug resistance in cancer cells. Results: miR-200bc/429 cluster was downregulated, while BCL2 and XIAP were upregulated in both MDR SGC7901/VCR (vincristine) and A549/CDDP (cisplatin) cells, compared with the parental SGC7901 and A549 cells, respectively. Overexpression of miR-200bc/429 cluster sensitized SGC7901/VCR and A549/CDDP cells to anti-cancer drugs, respectively. Both BCL2 and XIAP 3′-UTR reporters constructed in MDR cells suggested that BCL2 and XIAP were the common target genes of the miR-200bc/429 cluster. Enforced miR-200bc/429 cluster expression reduced BCL2 and XIAP protein level and sensitized both MDR cells to VCR-induced and CDDP-induced apoptosis, respectively. Conclusions: Our findings first suggest that miR-200bc/429 cluster could play a role in the development of MDR in both gastric and lung cancer cell lines, at least in part by modulation of apoptosis via targeting BCL2 and XIAP. [ABSTRACT FROM AUTHOR]