The quinoxaline di-N-oxide DCQ blocks breast cancer metastasis in vitro and in vivo by targeting the hypoxia inducible factor-1 pathway

BACKGROUND: Although tumor hypoxia poses challenges against conventional cancer treatments, it provides a therapeutic target for hypoxia-activated drugs. Here, we studied the effect of the hypoxia-activated synthetic quinoxaline di-N-oxide DCQ against breast cancer metastasis and identified the underlying mechanisms. METHODS: The human breast cancer cell lines MCF-7 (p53 wildtype) and MDA-MB-231 (p53 mutant) were treated with DCQ under normoxia or hypoxia. Drug toxicity on non-cancerous MCF-10A breast cells was also determined. In vitro cellular responses were investigated by flow cytometry, transfection, western blotting, ELISA and migration assays. The anti-metastatic effect of DCQ was validated in the MDA-MB-231 xenograft mouse model. RESULTS: DCQ selectively induced apoptosis in both human breast cancer cells preferentially under hypoxia without affecting the viability of non-cancerous MCF-10A. Cancer cell death was associated with an increase in reactive oxygen species (ROS) independently of p53 and was inhibited by antioxidants. DCQ-induced ROS was associated with DNA damage, the downregulation of hypoxia inducible factor-1 alpha (HIF-1α), and inhibition of vascular endothelial growth factor (VEGF) secretion. In MCF-7, HIF-1α inhibition was partially via p53-activation and was accompanied by a decrease in p-mTOR protein, suggesting interference with HIF-1α translation. In MDA-MB-231, DCQ reduced HIF-1α through proteasomal-dependent degradation mechanisms. HIF-1α inhibition by DCQ blocked VEGF secretion and invasion in MCF-7 and led to the inhibition of TWIST in MDA-MB-231. Consistently, DCQ exhibited robust antitumor activity in MDA-MB-231 breast cancer mouse xenografts, enhanced animal survival, and reduced metastatic dissemination to lungs and liver. CONCLUSION: DCQ is the first hypoxia-activated drug showing anti-metastatic effects against breast cancer, suggesting its potential use for breast cancer therapy

Flupirtine Derivatives as Potential Treatment for the Neuronal Ceroid Lipofuscinoses

OBJECTIVE: Neuronal Ceroid Lipofuscinoses (NCL) are fatal inherited neurodegenerative diseases with established neuronal cell death and increased ceramide levels in brain, hence, a need for disease-modifying drug candidates, with potential to enhance growth, reduce apoptosis and lower ceramide in neuronal precursor PC12 cells and human NCL cell lines using enhanced flupirtine aromatic carbamate derivatives in vitro. METHODS: Aromatic carbamate derivatives were tested by establishing growth curves under pro-apoptotic conditions and activity evaluated by trypan blue and JC-1 staining, as well as a drop in pro-apoptotic ceramide in neuronal precursor PC12 cells following siRNA knockdown of the RESULTS: Retigabine, the benzyl-derivatized carbamate and an allyl carbamate derivative were neuroprotective in CLN3-defective PC12 cells and rescued CLN1-/CLN2-/CLN3-/CLN6-/CLN8 patient-derived lymphoblasts from diminished growth and accelerated apoptosis. All drugs decreased ceramide in CLN1-/CLN2-/CLN3-/CLN6-/CLN8 patient-derived lymphoblasts. Increased INTERPRETATION: These findings establish that compounds analogous to flupirtine demonstrate anti-apoptotic activity with potential for treatment of NCL disease and use of ceramide as a marker for these diseases

Developmental Comparison of Ceramide in Wild-Type and Cln3Δex7/8 Mouse Brains and Sera

CLN3 disease is a neurodevelopmental disease leading to early visual failure, motor decline, and death. CLN3 pathogenesis has been linked to dysregulation of ceramide, a key intracellular messenger impacting various biological functions. Ceramide is upregulated in brains of CLN3 patients and activates apoptosis. Ceramide levels over the lifespan of WT and Cln3Δex7/8 mice were measured using the DGK assay. Ceramide subspecies were determined by LC-MS. Ceramide synthesis enzymes and pre- and post-synaptic mRNA expression was measured in Cln3Δex7/8 and normal mouse brains. Neuronal cell death was established by PARP cleavage and Caspases 3/6/9 and cytochrome C mRNA expression in Cln3Δex7/8 and normal mouse brains. In WT mouse, a ceramide peak was noted at 3 weeks of age. The absence of this peak in Cln3Δex7/8 mice might be related to early disease pathogenesis. Increase of ceramide in Cln3Δex7/8 mouse brain at 24 weeks of age precedes neuronal apoptosis. The correlation between serum and brain ceramide in WT mice, and dysregulation of ceramide in serum and brain of Cln3Δex7/8 mice, and the significant increase in ceramide in Cln3Δex7/8 mouse brains and sera argue for use of easily accessible serum ceramide levels to track response to novel therapies in human CLN3 disease

The regulation of RhoA at focal adhesions by StarD13 is important for astrocytoma cell motility

Malignant astrocytomas are highly invasive into adjacent and distant regions of the normal brain. Rho GTPases are small monomeric G proteins that play important roles in cytoskeleton rearrangement, cell motility, and tumor invasion. In the present study, we show that the knock down of StarD13, a GTPase activating protein (GAP) for RhoA and Cdc42, inhibits astrocytoma cell migration through modulating focal adhesion dynamics and cell adhesion. This effect is mediated by the resulting constitutive activation of RhoA and the subsequent indirect inhibition of Rac. Using Total Internal Reflection Fluorescence (TIRF)-based Förster Resonance Energy Transfer (FRET), we show that RhoA activity localizes with focal adhesions at the basal surface of astrocytoma cells. Moreover, the knock down of StarD13 inhibits the cycling of RhoA activation at the rear edge of cells, which makes them defective in retracting their tail. This study highlights the importance of the regulation of RhoA activity in focal adhesions of astrocytoma cells and establishes StarD13 as a GAP playing a major role in this process

Sex differences in gene expression with galactosylceramide treatment in Cln3Δex7/8 mice.

BackgroundCLN3 disease is caused by mutations in the CLN3 gene. The purpose of this study is to discern global expression patterns reflecting therapeutic targets in CLN3 disease.MethodsDifferential gene expression in vehicle-exposed mouse brain was determined after intraperitoneal vehicle/Galactosylceramide (GalCer) injections for 40 weeks with GeneChip Mouse Genome 430 2.0 arrays.ResultsAnalysis identified 66 genes in male and 30 in female brains differentially expressed in GalCer-treated versus vehicle-exposed Cln3Δex7/8 mice. Gene ontology revealed aberrations of biological function including developmental, cellular, and behavioral processes. GalCer treatment altered pathways of long-term potentiation/depression, estrogen signaling, synaptic vesicle cycle, ErbB signaling, and prion diseases in males, but prolactin signaling, selenium compound metabolism and steroid biosynthesis in females. Gene-gene network analysis highlighted networks functionally pertinent to GalCer treatment encompassing motor dysfunction, neurodegeneration, memory disorder, inflammation and astrogliosis in males, and, cataracts, inflammation, astrogliosis, and anxiety in females.ConclusionsThis study sheds light on global expression patterns following GalCer treatment of Cln3Δex7/8 mice. Understanding molecular effects of GalCer on mouse brain gene expression, paves the way for personalized strategies for treating this debilitating disease in humans