Background:HOX transcript antisense RNA (HOTAIR), which is expressed from the homebox C gene (HOXC) locus, is capable of reprogramming chromatin organisation and promoting cancer cell metastasis and can simultaneously bind the polycomb repressive complex 2, which enhances H3K27 trimethylation, and the LSD1-CoREST-REST complex, which is critical for H3K4 demethylation. Clinically, the overexpression of HOTAIR is a powerful predictor of the tumour progression and overall survival in patients with diverse cancers. The relationship between HOTAIR and oesophageal squamous cell carcinoma (ESCC), however, remains unclear. We investigated the role of HOTAIR in the pathogenesis of ESCC.Methods:We used quantitative real-time PCR to determine the level of HOTAIR in ESCC cell lines and 100 ESCC samples from patients; 56 adjacent non-neoplastic tissues were used as controls. We measured the effect of HOTAIR knockdown and overexpression in ESCC cell lines using colony formation assays, anchorage-independent growth assays, the CCK-8 assay, transwell migration and invasion assays, and Annexin V-binding assays. We analysed the growth of ESCC xenograft tumours in nude mice. Changes in the gene expression and methylation levels in ESCC cell lines were analysed using gene expression microarrays and the Infinium HumanMethylation450K BeadChip assay, respectively.Results:The levels of HOTAIR were increased in ESCC cell lines and patient samples compared with the controls; the expression levels correlated with the disease stage and survival time. The knockdown of HOTAIR in the KYSE510 and KYSE180 ESCC cell lines using small hairpin RNAs (shRNAs) reduced the ability of the cells to form foci, migrate, and invade the extracellular matrix in culture, altered cell cycle progression, and increased the sensitivity of the cells to apoptosis. The HOTAIR knockdown reduced cancer cell metastasis in vivo, and the tumours formed by HOTAIR-silenced ESCC cells were smaller, both in size and weight, than the tumours and metastases formed by the shRNA vector control cells in a mouse xenograft model. The results of the gene microarray study showed that HOTAIR reprogrammed the gene expression profile of ESCC cells, and the gene ontology analysis revealed an enrichment in genes that are important for tumorigenesis, such as genes involved in cell migration and the regulation of the cell cycle. Comparing the gene expression profiles and DNA methylation analysis between the KYSE180 and KYSE180_HOTAIR cells revealed that only a small proportion of the methylation changes were correlated with gene expression changes.Conclusion:HOX transcript antisense RNA is upregulated in ESCC cell lines and patient samples, and promotes ESCC cell proliferation and tumour metastasis in mice. The knockdown of HOTAIR resulted in significant changes in gene expression, and data analysis suggested that HOTAIR-mediated gene regulation has a critical role in ESCC progression and is a novel epigenetic molecular target for treating ESCC patients.
In this paper, we obtain a global exact controllability result for a class of multidimensional semilinear hyperbolic equations with a superlinear nonlinearity and variable coefficients. For this purpose, we establish an observability estimate for the linear hyperbolic equation with an unbounded potential, in which the crucial observability constant is estimated explicitly by a function of the norm of the potential. Such an estimate is obtained by a combination of a pointwise estimate and a global Carleman estimate for the hyperbolic differential operators and analysis on the regularity of the optimal solution to an auxiliary optimal control problem.
Chalcones (1,3-diaryl-2-propen-1-ones) are precursors for flavonoids and isoflavonoids, which are common simple chemical scaffolds found in many naturally occurring compounds. Many chalcone derivatives were also prepared due to their convenient synthesis. Chalcones as weandhetic analogues have attracted much interest due to their broad biological activities with clinical potentials against various diseases, particularly for antitumor activity. The chalcone family has demonstrated potential in vitro and in vivo activity against cancers via multiple mechanisms, including cell cycle disruption, autophagy regulation, apoptosis induction, and immunomodulatory and inflammatory mediators. It represents a promising strategy to develop chalcones as novel anticancer agents. In addition, the combination of chalcones and other therapies is expected to be an effective way to improve anticancer therapeutic efficacy. However, despite the encouraging results for their response to cancers observed in clinical studies, a full description of toxicity is required for their clinical use as safe drugs for the treatment of cancer. In this review, we will summarize the recent advances of the chalcone family as potential anticancer agents and the mechanisms of action. Besides, future applications and scope of the chalcone family toward the treatment and prevention of cancer are brought out.
Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer in adults. Previous studies in our laboratory found that long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was upregulated in HCC cells, which could affect the metastasis and invasion of HCC. However, the underlying mechanism remains unknown. Herein, we studied the interaction between MALAT1 and miR-140 on the regulation of angiogenesis and immunosuppressive properties. We revealed that the expression of MALAT1 and VEGF-A was significantly increased in HCC cells. Knockdown of MALAT1 in HCC cells suppressed the production of VEGF-A, impaired the angiogenesis of HUVECs, and facilitated the polarization of macrophage toward the M1 subset. Mechanistically, the interaction between MALAT1 and miR-140 or between miR-140 and VEGF-A was confirmed by multiple assays. Besides, a negative correlation between MALAT1 and miR-140 was found in HCC tissues. Furthermore, miR-140 inhibition significantly increased VEGF-A expression, promoted angiogenesis of HUVECs, and redirected the polarization of macrophages toward the M2 subset. In addition, in vivo studies also verified the regulatory network of the MALAT1/miR-140 axis on VEGF-A in HCC progression. In summary, this study revealed the mechanism that MALAT1 worked as a putative HCC promotor via inhibiting miR-140. Therefore, targeting MALAT1 or miR-140 might alleviate the progression of HCC in the future.
Increasing evidence supports the significance of long non-coding RNA in cancer development. Several recent studies suggest the oncogenic activity of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in hepatocellular carcinoma. In this study, we explored the molecular mechanisms by which MALAT1 modulates hepatocellular carcinoma biological behaviors. We found that microRNA-204 was significantly downregulated in sh-MALAT1 HepG2 cell and 15 hepatocellular carcinoma tissues by quantitative real-time polymerase chain reaction analysis. Through bioinformatic screening, luciferase reporter assay, RNA-binding protein immunoprecipitation, and RNA pull-down assay, we identified microRNA-204 as a potential interacting partner for MALAT1. Functionally, wound-healing and transwell assays revealed that microRNA-204 significantly inhibited the migration and invasion of hepatocellular carcinoma cells. Notably, sirtuin 1 was recognized as a direct downstream target of microRNA-204 in HepG2 cells. Moreover, si-SIRT1 significantly inhibited cell invasion and migration process. These data elucidated, by sponging and competitive binding to microRNA-204, MALAT1 releases the suppression on sirtuin 1, which in turn promotes hepatocellular carcinoma migration and invasion. This study reveals a novel mechanism by which MALAT1 stimulates hepatocellular carcinoma progression and justifies targeting metastasis-associated lung adenocarcinoma transcript 1 as a potential therapy for hepatocellular carcinoma.
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