Serum microRNA expression profiling revealing potential diagnostic biomarkers for lung adenocarcinoma.

BACKGROUND: Recent studies have demonstrated that microRNAs (miRNAs) in the blood circulation can serve as promising diagnostic markers for cancers. This four-stage study aimed at finding serum miRNAs as potential biomarkers for lung adenocarcinoma (LA) diagnosis. METHODS: The study was carried out between 2016 and 2017. The Exiqon miRNA qPCR panel (3 LA vs. 1 normal control [NC] pooled serum samples) was used for initial screening to acquire miRNA profiles. Thirty-five dysregulated miRNAs were further evaluated in the training (24 LA vs. 24 NCs) and testing stages (110 LA vs. 110 NCs) using quantitative real-time polymerase chain reaction assays. RESULTS: Four serum miRNAs (miR-133a-3p, miR-584-5p, miR-10b-5p, and miR-221-3p) were significantly overexpressed in LA patients compared with NCs. The diagnostic value of the four-miRNA panel was validated by an external cohort (36 LA vs. 36 NCs). The areas under the receiver operating characteristic curve of the four-miRNA panel in the training, testing, and external validation stages were 0.734, 0.803, and 0.894 respectively. Meanwhile, the expression level of miR-221-3p was much higher in LA tumor samples than that in the adjacent normal tissues (19 LA vs. 19 NCs). The expression level of miR-10b-5p was also elevated in the serum-derived exosomes samples (18 LA vs. 18 NCs). The expression of miR-133a-3p, miR-584-5p, and miR-10b-5p was significantly elevated in LA patients with epidermal growth factor receptor mutation compared with NCs. CONCLUSION: The study established a four-miRNA signature in serum that could improve the diagnostic capability of LA.

[Down-regulation of mTOR activity and survivin expression during tamoxifen-induced apoptosis in hepatoblastoma cells].

OBJECTIVE: The aim of this study was to investigate the changes in mTOR activity and survivin expression in liver cancer cell line HepG2 cells treated with tamoxifen. METHODS: Survivin transcription level and p70S6K was demonstrated by PCR, dual-luciferase reporter assay and Western blot analysis, respectively, and the apoptosis in the HepG2 cells was detected by flow cytometry. RESULTS: Tamoxifen leads to apoptosis of the cells and reduction in survivin expression, as well as a dramatic reduction in the activated form of p70S6K. Treating HepG2 cells with rapamycin, a specific mTOR inhibitor, significantly reduced the survivin protein level but not affected the survivin transcription, indicating that tamoxifen and rapamycin were synergistic in regards to down-regulation of survivin expression in hepatocellular carcinoma cells. CONCLUSIONS: Our results suggest that tamoxifen down-regulates survivin expression in HepG2 cells and it is mediated by transcriptional and post-transcriptional level via PI3K/Akt/mTOR pathway to induce apoptosis.

Overexpression of cyclin L2 induces apoptosis and cell-cycle arrest in human lung cancer cells.

BACKGROUND: Uncontrolled cell division is one of the hallmarks of tumor growth. Researches have been focused on numerous molecules involved in this process. Cyclins are critical regulatory proteins of cell cycle progression and/or transcription. The present study aimed to investigate the anti-proliferative effect of cyclin L2, and to define its growth regulatory mechanisms using human lung adenocarcinoma cell line A549. METHODS: Human cyclin L2 was transfected into human lung adenocarcinoma cells (A549 cell), and was expressed in a mammalian expression vector pcDNA3.1. The effects and mechanisms of the cyclin L2 in cell growth, cell cycle analysis and apoptosis were studied by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), flow cytometry or Western blot, respectively. RESULTS: Overexpression of cyclin L2 inhibited the growth of A549 cells. Cell cycle analysis in cells transfected with pCCNL2 revealed an increment in proportion in G0/G1 phase ((68.07 +/- 4.2)%) in contrast to (60.39 +/- 2.82)% of the cells transfected with mock vector. Apoptosis occurred in (7.25 +/- 0.98)% cells transfected with pCCNL2, as compared with (1.25 +/- 0.21)% of the mock vector control group. Cyclin L2-induced-G0/G1 arrest and apoptosis involved upregulation of caspase-3 and downregulation of Bcl-2 and survivin. CONCLUSION: The results indicate that overexpression of cyclin L2 protein may promote efficient growth inhibition of human lung adenocarcinoma cells by inducing G0/G1 cell cycle arrest and apoptosis.

[Expression of livin in gastric cancer and effect of silencing of the livin gene on apoptosis in gastric cancer cells].

OBJECTIVE: The aim of this study was to detect the expression of livin in human gastric carcinoma and analyze the relationship between livin expression and cliniopathologic features. To explore the feasibility of small interference RNA (siRNA) in inhibition of livin gene expression and to investigate the apoptosis susceptibility of SGC-7901 cells by siRNA-mediated silencing of the livin gene. METHODS: The expression of livin at mRNA and protein levels were determined by RT-PCR and Western blot assay, respectively. The relationship between livin expression and clinicopathologic features was analyzed. Two siRNAs specifically targeting livin gene were designed and synthesized in vitro, and were transfected into the gastric cancer SGC-7901 cells. The expression of livin mRNA was assayed by RT-PCR. Cell growth state and 50% inhibition concentration (IC50) of 5-Fu and cisplatin on SGC-7901 cells were determined by MTT method. Cell apoptosis was assessed by flow cytometry (FCM). RESULTS: The expressions of livin mRNA and protein were detected in 19 of 40 gastric carcinoma cases (47.5%). No expression of livin was detected in tumor-adjacent tissues and benign gastric lesion. A positive correlation was found between livin expression and poor differentiation as well as lymph node metastases (P < 0.05). The level of livin mRNA was decreased in the SGC-7901 cells transfected by si-livin1 for 48 hours, with inhibition of cell growth. IC50 of si-livin-treated SGC-7901 cells to 5-Fu and cisplatin was decreased (P < 0.05) and the cells were more susceptible to proapoptotic stimuli (5-Fu and cisplatin) than control groups (P < 0.05). CONCLUSION: Livin is overexpressed in gastric carcinoma with a correlation to tumor differentiation and lymph node metastasis, suggesting that it may be as one of molecular prognostic factors for some cases of gastric cancer. SiRNA can inhibit livin expression of SGC-7901 cells and induce cell apoptosis. Livin might serve as a new target for apoptosis-inducing therapy of gastric cancer. Livin;