Effects of siRNA-Mediated Knockdown of HDAC1 on the Biological Behavior of Esophageal Carcinoma Cell Lines

Targeting Strategies for Aberrant Lipid Metabolism Reprogramming and the Immune Microenvironment in Esophageal Cancer: A Review

Esophageal cancer is of high importance to occurrence, development, and treatment resistance. As evidenced by recent studies, pathways (e.g., Wnt/β-catenin, AMPK, and Hippo) are critical to the proliferation, differentiation, and self-renewal of esophageal cancer. In addition, the above pathways play a certain role in regulating esophageal cancer and act as potential therapeutic targets. Over the past few years, the function of lipid metabolism in controlling tumor cells and immune cells has aroused extensive attention. It has been reported that there are intricate interactions between lipid metabolism reprogramming between immune and esophageal cancer cells, whereas molecular mechanisms should be studied in depth. Immune cells have been commonly recognized as a vital player in the esophageal cancer microenvironment, having complex crosstalk with cancer cells. It is increasingly evidenced that the function of immune cells in the tumor microenvironment (TME) is significantly correlated with abnormal lipid metabolism. In this review, the latest findings in lipid metabolism reprogramming in TME are summarized, and the above findings are linked to esophageal cancer progression. Aberrant lipid metabolism and associated signaling pathways are likely to serve as a novel strategy to treat esophageal cancer through lipid metabolism reprogramming.

Suppression of histone deacetylase 1 by JSL-1 attenuates the progression and metastasis of cholangiocarcinoma via the TPX2/Snail axis

Histone deacetylases (HDACs) are entwined with the pathogenesis of various cancers and potentially serve as promising therapeutic targets. Herein, we intend to explore the potential role of HDAC1 inhibitor (JSL-1) in the tumorigenesis and metastasis of cholangiocarcinoma (CC) and to highlight the molecular basis of its function. As shown by bioinformatics analysis and immunohistochemical detection, high HDAC1 expression was witnessed in CC tissues relative to matched controls from patients with cholecystitis. The molecular network that HDAC1 silencing reduced the enrichment of HDAC1 and Snail on the TPX2 promoter was identified using immunoprecipitation and chromatin immunoprecipitation assays. Both short hairpin RNA (shRNA)-mediated knockdown of HDAC1 and JSL-1 treatment exhibited anti-proliferative, anti-migration and anti-invasion effects on CC cells through downregulation of TPX2. The in vivo xenograft model was developed in nude mice. Consistently, the anti-tumorigenic and anti-metastatic properties of shRNA against HDAC1 and HDAC1 inhibitor were validated in the in vivo settings. Taken together, our data supported the notion that HDAC1 inhibitor retards the initiation and development of CC via mediating the TPX2/Snail axis, highlighting the anti-tumor molecular network functioned in CC.

Epigenetic Alterations in Oesophageal Cancer: Expression and Role of the Involved Enzymes

Oesophageal cancer is a life-threatening disease, accounting for high mortality rates. The poor prognosis of this malignancy is mostly due to late diagnosis and lack of effective therapies for advanced disease. Epigenetic alterations may constitute novel and attractive therapeutic targets, owing to their ubiquity in cancer and their reversible nature. Herein, we offer an overview of the most important studies which compared differences in expression of enzymes that mediate epigenetic alterations between oesophageal cancer and normal mucosa, as well as in vitro data addressing the role of these genes/proteins in oesophageal cancer. Furthermore, The Cancer Genome Atlas database was interrogated for the correlation between expression of these epigenetic markers and standard clinicopathological features. We concluded that most epigenetic players studied thus far are overexpressed in tumours compared to normal tissue. Furthermore, functional assays suggest an oncogenic role for most of those enzymes, supporting their potential as therapeutic targets in oesophageal cancer.

HDAC1 overexpression enhances β-cell proliferation by down-regulating Cdkn1b/p27

The homeobox transcription factor Nkx6.1 is sufficient to increase functional β-cell mass, where functional β-cell mass refers to the combination of β-cell proliferation, glucose-stimulated insulin secretion (GSIS) and β-cell survival. Here, we demonstrate that the histone deacetylase 1 (HDAC1), which is an early target of Nkx6.1, is sufficient to increase functional β-cell mass. We show that HDAC activity is necessary for Nkx6.1-mediated proliferation, and that HDAC1 is sufficient to increase β-cell proliferation in primary rat islets and the INS-1 832/13 β-cell line. The increase in HDAC1-mediated proliferation occurs while maintaining GSIS and increasing β-cell survival in response to apoptotic stimuli. We demonstrate that HDAC1 overexpression results in decreased expression of the cell cycle inhibitor Cdkn1b/p27 which is essential for inhibiting the G1 to S phase transition of the cell cycle. This corresponds with increased expression of key cell cycle activators, such as Cyclin A2, Cyclin B1 and E2F1, which are activated by activation of the Cdk4/Cdk6/Cyclin D holoenzymes due to down-regulation of Cdkn1b/p27. Finally, we demonstrate that overexpression of Cdkn1b/p27 inhibits HDAC1-mediated β-cell proliferation. Our data suggest that HDAC1 is critical for the Nkx6.1-mediated pathway that enhances functional β-cell mass.

Curcumol Controls Choriocarcinoma Stem-Like Cells Self-Renewal via Repression of DNA Methyltransferase (DNMT)- and Histone Deacetylase (HDAC)-Mediated Epigenetic Regulation

BACKGROUND Cancer stem cells (CSCs), in choriocarcinoma and other carcinomas, possess the ability of self-renewal and multilineage differentiation potential. We previous isolated choriocarcinoma cancer stem-like cells (CSLCs), which hold the stemness characteristics of CSCs. Epigenetic modifications have emerged as drivers in tumorigenesis, but the mechanisms of CSCs are largely unknown, and new drug therapies are needed to break the persistence of CSCs. MATERIAL AND METHODS Quantitative real-time PCR (qRT-PCR) and Western blot analysis were performed to detect the expression of DNMTs, HDACs, and stemness-genes. DNMTs and HDACs silencing and overexpressing lentivirus were transfected into JEG-3 cells to investigate the epigenetic functions in CSLCs. In vivo expression of curcumol effects of CSLCs on DNMTs and HDACs were analyzed by immunohistochemistry. RESULTS Expression of DNMT1, DNMT3b, HDAC1, and HDAC3 were increased in choriocarcinoma CSLCs. Consistent with the inhibitory effect of 5-AzaC and TSA on CSLCs, DNMT/HDAC knockdown displayed significant repression of self-renewal in CSLCs. Curcumol inhibited the stemness ability of CSLCs in vitro and in vivo, and the inhibitory effect we observed was mediated in part through repressing activity of DNMTs and HDACs. Importantly, curcumol showed a better effect than DNMT and HDAC inhibitors combined in eliminating CSLCs. CONCLUSIONS These findings indicate that DNMT- and HDAC-mediated epigenetic regulation plays an important role in the biology of choriocarcinoma CSLCs, and curcumol has the potential to be a new drug to fight CSLCs, warranting further investigation of epigenetic-based therapies.