Romidepsin hepatocellular carcinoma suppression in mice is associated with deregulated gene expression of bone morphogenetic protein and Notch signaling pathway components.

Recently, our group showed that Romidepsin, a histone deacetylase inhibitor (HDACi), suppressed diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in mice. In the present study, we investigated the effect of Romidepsin-treatment on gene expression levels of components of Bmp and Notch signaling pathways, which are both known to be aberrantly regulated in hepatocarcinogenesis. Total RNA from liver tissue samples and paraffin-embedded livers were retrieved from a recent experiment where C57BL/6 mice were treated with Romidepsin 10 months after DEN challenge and sacrificed 2 months later. RT qPCR was used for quantification of gene expression and immunohistochemistry for in situ protein detection. Regarding Bmp pathway, Romidepsin HCC-suppression was found to correlate significantly with Bmp2 and Bmp7 ligand up- and down-regulation, respectively. Intracellularly, Romidepsin-treated HCC mice exhibited a significant elevation of Bmp-inhibitor Smurf2 and Bmp-target gene Id3, as compared to the HCC untreated controls. Concerning Notch signaling, higher expression levels of ligands Jag1/Dll4, accompanied by a decreased expression of receptor Notch2, were identified in the Romidepsin-treated group. Τhe anti-oncogenic effect of Romidepsin, also correlated significantly with an increased expression of Hes1 target, as well as an up- and down-regulation of Klf4 and Sox9 transcription factors, respectively. Moreover, the cancer-related genes Snai2 and p21, known to be involved in many signaling pathways, including Bmp and Notch, were also found to be downregulated in Romidepsin-treated mice. Romidepsin HCC suppression is associated with gene expression deregulation of selective components of both Bmp and Notch signaling cascades.

Endogenous Notch Signaling in Adult Kidneys Maintains Segment-Specific Epithelial Cell Types of the Distal Tubules and Collecting Ducts to Ensure Water Homeostasis.

BACKGROUND: Notch signaling is required during kidney development for nephron formation and principal cell fate selection within the collecting ducts. Whether Notch signaling is required in the adult kidney to maintain epithelial diversity, or whether its loss can trigger principal cell transdifferentiation (which could explain acquired diabetes insipidus in patients receiving lithium) is unclear. METHODS: To investigate whether loss of Notch signaling can trigger principal cells to lose their identity, we genetically inactivated Notch1 and Notch2, inactivated the Notch signaling target Hes1, or induced expression of a Notch signaling inhibitor in all of the nephron segments and collecting ducts in mice after kidney development. We examined renal function and cell type composition of control littermates and mice with conditional Notch signaling inactivation in adult renal epithelia. In addition, we traced the fate of genetically labeled adult kidney collecting duct principal cells after Hes1 inactivation or lithium treatment. RESULTS: Notch signaling was required for maintenance of Aqp2-expressing cells in distal nephron and collecting duct segments in adult kidneys. Fate tracing revealed mature principal cells in the inner stripe of the outer medulla converted to intercalated cells after genetic inactivation of Hes1 and, to a lesser extent, lithium treatment. Hes1 ensured repression of Foxi1 to prevent the intercalated cell program from turning on in mature Aqp2+ cell types. CONCLUSIONS: Notch signaling viaHes1 regulates maintenance of mature renal epithelial cell states. Loss of Notch signaling or use of lithium can trigger transdifferentiation of mature principal cells to intercalated cells in adult kidneys.

Cervical Cancer Cell Growth, Drug Resistance, and Epithelial-Mesenchymal Transition Are Suppressed by y-Secretase Inhibitor RO4929097.

BACKGROUND The Notch signaling pathway has been reported to play a pivotal role in tumorigenesis. Emerging evidence has demonstrated that the Notch signaling pathway regulates several cellular processes. The present study investigated the effect of the Notch signaling pathway on cell growth, invasiveness, and drug resistance, as well as epithelial-mesenchymal transition (EMT), of cervical cancer cells. MATERIAL AND METHODS We used quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis to measure the expression level of Notch2. CCK-8, clonality, wound healing, and Transwell assays were used to evaluate the effect of γ-secretase inhibitor (GSI) RO4929097 on cervical cancer cell lines HeLa and Caski. To explore the role of the Notch signaling pathway in EMT, the epithelial and mesenchymal markers were detected by qRT-PCR and Western blot after cervical cancer cell lines were treated with GSI RO4929097. RESULTS The expression of Notch2 was found to increase in cervical cancer cell lines compared with the normal immortalized human cervical epithelial cells. GSI RO4929097 was confirmed to inhibit the Notch signaling pathway and impaired the proliferation, drug resistance, migration, and invasion abilities of cervical cancer cells. The protein expression levels of the mesenchymal biomarkers Snail, Twist, and neural cadherin (N-cadherin) decreased; however, the expression of the epithelial biomarker epithelial cadherin (E-cadherin) increased in the cervical cancer cells treated with GSI RO4929097. CONCLUSIONS Notch signaling pathway plays an important role in the development and progression of cervical cancer. Blockade of the Notch pathway using GSI RO4929097 inhibited cell growth and reduced chemoresistance, invasion, metastasis, and EMT in cervical cancer cells.

Correlative analyses of notch signaling with resveratrol-induced differentiation and apoptosis of human medulloblastoma cells.

Altered Notch signaling seems linked with medulloblastoma (MB) formation and resveratrol exhibits anti-medulloblastoma effects. However, the influence of resveratrol in Notch signaling of MB cells has not been described. This issue was addressed here by checking Notch1 and Notch2 statuses in three MB cell lines with and without resveratrol treatment. Notch1 and Notch2 were detected in the cytoplasm of three cell lines under normal condition, which were up-regulated by resveratrol along with differentiation, apoptosis and enhanced Hes1 nuclear translocation. Nevertheless, blockage of Notch enzymatic cleavage with gamma-seacretase inhibitors, DAPT and L-685,458, neither interrupted resveratrol-caused cellular events nor affected MB cell growth. These results demonstrate that Notch signaling has little relevance with resveratrol-induced differentiation and apoptosis and may not be a universal critical factor of MB cells.