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Background MicroRNAs (miRNAs) play crucial roles in varieties of cancers, particularly in tumorigenesis, progression, and migration. Dysregulation of miR-28 was reported to occur in various types of human malignancies. In humans, two different mature miRNA sequences are excised from opposite arms of the stem-loop pre-miR-28, hsa-miR-28-3p and hsamiR-28-5p. However, the expression and distinct role of miR-28-3p and miR-28-5p in nasopharyngeal carcinoma (NPC) remain undetermined. Methods The expressions of miR-28-3p/-5p in human NPC tissues were tested by quantitative real-time PCR. miR-28-3p/-5p were overexpressed by mimics and silenced by inhibitors. The roles of miR-28-3p/-5p in NPC development were studied using cultured HONE-1 cells. Results The mRNA expression levels of miR-28-3p and -5p were significantly decreased in NPC tissues in comparison with adjacent normal tissues. Overexpression of miR-28-5p suppressed NPC cell proliferation and induced cell cycle arrest and apoptosis, while miR-28-3p promoted NPC cell migration and invasion. The miRNAs effected on different signal pathways: miR-28-5p altered expression of cyclin D1 and influenced the PI3K/AKT signaling pathway. In contrast, miR-28-3p downregulated Nm23-H1 and accelerated the process of EMT. Conclusion miR-28-3p and -5p were both downregulated in NPC tissues but had distinct biological effects in NPC cells. They may serve as potential prognostic markers and therapeutic targets for NPC.

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Background/Aims: Lymphocyte antigen 6 complex, locus E (LY6E) is a member of the lymphostromal cell membrane Ly6 superfamily protein. The present study investigated the clinical significance and potential biological function of LY6E in gastric cancer (GC). Methods: LY6E mRNA and protein expressions in human GC tissues and GC cells were tested. Relationship between LY6E expression and the GC patients’ clinicopathologic characteristics was analyzed. LY6E was silenced by siRNA in the cultured GC cells. Results: The RNA expression microarray profiling assay results demonstrated that LY6E mRNA was significantly increased in multiple human GC tumor tissues. Immunohistochemistry (IHC) staining analysis revealed that 59 of 75 (78.7%) GC specimens were LY6E positive. LY6E over-expression in human GC was correlated with the histology grade, AJCC stage, N classification, lymphatic invasion, and tumor location. Notably, functional LY6E expression was also detected in AGS and other established GC cell lines. LY6E knockdown by targeted-siRNA inhibited AGS cell survival and proliferation. Meanwhile, the LY6E siRNA induced G1-S cell cycle arrest and apoptosis in AGC cells. Additionally, AGC cell migration was also inhibited by LY6E knockdown. Expressions of tumor-suppressing proteins, including PTEN (phosphatase and tensin homolog) and E-Cadherin, were increased in LY6E-silenced AGS cells. Conclusion: LY6E over-expression in GC is potentially required for cancer cell survival, proliferation and migration.

TBX2 is a member of the T box transcription factor family. Its expression and potential biological functions in nasopharyngeal cancer (NPC) cells are studied here. We showed that TBX2 mRNA and protein expression was significantly elevated in multiple human NPC tissues, as compared with that in adjacent normal tissues. Knockdown of TBX2 by targeted-siRNA significantly inhibited proliferation and invasion of NPC cells (CNE-1 and HONE-1 lines). Meanwhile, TBX2 knockdown also induced G1-phase cell cycle arrest. At the molecular level, we discovered that expressions of several tumor suppressor genes, including p21, p27, phosphatase with tensin homology (PTEN) and E-Cadherin, were increased dramatically after TBX2 knockdown in above NPC cells. Collectively, our results imply that TBX2 over-expression promotes NPC cell proliferation and invasion, possibly via silencing several key tumor suppressor genes.

Background/Aims: Human hedgehog-interacting protein (HHIP) is a negative regulator of the hedgehog (HH) signaling pathway. It is deregulated in gastric cancer. The underlying molecular mechanism of HHIP-induced inhibition of HH signaling remains to be determined. Methods: A lentiviral HHIP expression vector (“LV-HHIP”) was established to exogenously over-express HHIP in gastric cancer cells. HHIP protein and mRNA were tested by Western blotting assay and quantitative real-time PCR assay, respectively. Cell survival was tested by the Cell Counting Kit-8 (CCK-8) assay. Cell proliferation was examined by the BrdU ELISA assay and [H³] Thymidine DNA incorporation assay. Cell invasion and migration were tested by the phagokinetic track assay and the “Transwell” assay. The bisulfite-sequencing PCR was applied to test HHIP promoter methylation. Results: In the established (AGS cell line) and primary human gastric cancer cells, LV-HHIP transfection increased HHIP expression and inhibited cancer cell survival and proliferation as well as cell migration and invasion. Furthermore, LV-HHIP significantly attenuated promoter methylation of the endogenous HHIP gene in AGS cells, causing it upregulation. Inhibition of methylation by 5-aza-dc similarly induced HHIP expression in gastric cancer cells, which inhibited cancer cell proliferation and migration. Conclusions: Our results suggest that inhibition of HHIP promoter methylation can efficiently inhibit human gastric cancer cell proliferation and migration.

The author had organized raw data in the article recently and found that data arrangement for some experiments existed incorrectly. Afterwards, these experiments were carried out again and updated the data for the assays. The updated images (Figs. 2C, D, E, 4B, C, D) are shown below.

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