Anticancer agents interacting with membrane glucose transporters

The altered metabolism observed in cancer cells generally consists of increased glucose uptake and glycolytic activity. This is associated with an overexpression of glucose transporter proteins (GLUTs), which facilitate glucose uptake across the plasma membrane and play a crucial role in the survival of cancer cells. Therefore, GLUTs are considered as suitable targets for treatment of cancer. Herein we review some of the most relevant GLUT inhibitors that have been recently developed as prospective anticancer agents

Impairment of lysosomal activity as a therapeutic modality targeting cancer stem cells of embryonal rhabdomyosarcoma cell line RD.

Rhabdomyosarcoma is the most frequent soft tissue sarcoma in children and adolescents, with a high rate of relapse that dramatically affects the clinical outcome. Multiagent chemotherapy, in combination with surgery and/or radiation therapy, is the treatment of choice. However, the relapse rate is disappointingly high and identification of new therapeutic tools is urgently needed. Under this respect, the selective block of key features of cancer stem cells (CSC) appears particularly promising. In this study, we isolated rhabdomyosarcoma CSC with stem-like features (high expression of NANOG and OCT3/ 4, self-renewal ability, multipotency). Rhabdomyosarcoma CSC showed higher invasive ability and a reduced cytotoxicity to doxorubicin in comparison to native cells, through a mechanism unrelated to the classical multidrug resistance process. This was dependent on a high level of lysosome acidity mediated by a high expression of vacuolar ATPase (V-ATPase). Since it was not associated with other paediatric cancers, like Ewing\u2019s sarcoma and neuroblastoma, V-ATPase higher expression in CSC was rhabdomyosarcoma specific. Inhibition of lysosomal acidification by the V-ATPase inhibitor omeprazole, or by specific siRNA silencing, significantly enhanced doxorubicin cytoxicity. Unexpectedly, lysosomal targeting also blocked cell growth and reduced the invasive potential of rhabdomyosarcoma CSC, even at very low doses of omeprazole (10 and 50 mM, respectively). Based on these observations, we propose lysosome acidity as a valuable target to enhance chemosensitivity of rhabdomyosarcoma CSC, and suggest the use of anti-V-ATPase agents in combination with standard regimens as a promising tool for the eradication of minimal residual disease or the prevention of metastatic disease

CRIPTO and its signaling partner GRP78 drive the metastatic phenotype in human osteotropic prostate cancer

CRIPTO (CR-1, TDGF1) is a cell surface/secreted oncoprotein actively involved in development and cancer. Here, we report that high expression of CRIPTO correlates with poor survival in stratified risk groups of prostate cancer (PCa) patients. CRIPTO and its signaling partner glucose-regulated protein 78 (GRP78) are highly expressed in PCa metastases and display higher levels in the metastatic ALDHhigh sub-population of PC-3M-Pro4Luc2 PCa cells compared with non-metastatic ALDHlow. Coculture of the osteotropic PC-3M-Pro4Luc2 PCa cells with differentiated primary human osteoblasts induced CRIPTO and GRP78 expression in cancer cells and increases the size of the ALDHhigh sub-population. Additionally, CRIPTO or GRP78 knockdown decreases proliferation, migration, clonogenicity and the size of the metastasis-initiating ALDHhigh sub-population. CRIPTO knockdown reduces the invasion of PC-3M-Pro4Luc2 cells in zebrafish and inhibits bone metastasis in a preclinical mouse model. These results highlight a functional role for CRIPTO and GRP78 in PCa metastasis and suggest that targeting CRIPTO/GRP78 signaling may have significant therapeutic potential.Oncogene advance online publication, 10 April 2017; doi:10.1038/onc.2017.87

Microbiological and chemical monitoring of Marsala base wine obtained by spontaneous fermentation during large-scale production

The present work was undertaken to evaluate the effect of the natural winemaking on the microbial and chemical composition of Marsala base wine. To this purpose, a large-scale vinification process of Grillo grape cultivar was monitored from harvesting to the final product. Total yeasts (TY) showed a rapid increase after must pressing and reached values almost superimposable to those registered during the conventional winemakings. Lactic acid bacteria (LAB) were registered at the highest levels simultaneously to yeast growth at the beginning of the process. Saccharomyces cerevisiae was the species found at the highest concentrations in all samples analysed. Several strains (n= 16) was registered at high levels during the alcoholic fermentation and/or aging of wine; only two of them were detected on the grape surface. Lactobacillus plantarum was the LAB species most frequently isolated during the entire vinification process. Ethanol content was approximately 14% (v/v) at the end of vinification. The value of pH did not greatly vary during the process and the volatile acidity (VA) was detected at low concentrations during the entire transformation. The concentration of malic acid rapidly decreased during the AF; on the other hand, lactic acid showed an irregular trend during the entire process. trans-caffeil tartaric acid was the most abundant hydroxycinnamoyl tartaric acid and volatile organic compounds (VOC) were mainly represented by isoamylic alcohol and isobutanol

Salicylketoximes as inhibitors of Glucose Transporters

Some derivatives of the 4-arylsalicylketoximes series displayed inhibitory effects on glucose transport and on cell proliferation in several biological assays,[1] resulting to be effective GLUT1 inhibitors also in GLUT1-containing giant vesicles. GLUT1 is one of the 14 glucose transporter isoforms, widely overexpressed in many cancer types. Thus, for the discovered properties, the oximes of interest represent interesting candidates for anticancer therapy. Variously substituted 4-arylsalicylketoximes (3, Fig.1) were synthetized via Suzuki cross-coupling and a subsequent condensation of the resulting biaryl-ketone intermediates with hydroxylamine hydrochloride. [1] Rat GLUT1 membrane proteins were produced by Pichia Pastoris cultures, and purified following GLUT1 purification protocols, [2] which were largely revised to avoid the protein cleavage. Compounds 3a, 3b, 3e, and 3f efficiently inhibited glucose uptake in GLUT1-containing giant vesicle assays. [3] To study the nature of the binding process between GLUT1 and the synthetic compounds, many crystallization attempts were set up with 3a and 3e using Lipidic Cubic Phase method, which produced many small crystals. Since many isoforms of GLUTs are overexpressed in cancer cells, inhibition of other GLUT isoforms, such as GLUT3, will be tested in the near future. In conclusion, 4-arylsalicylketoximes showed good inhibition of GLUT1 isoform. First results from GLUT3-giant vesicles assays revealed that, within this series of compounds, 3a is the most selective GLUT1-inhibitor. Further assays with GLUTs-containing giant vesicle and crystallization attempts are currently underway. [1] Granchi C, Qian Y, Lee H.Y, Paterni I, Pasero C, Iegre J, Carlson K. E, Tuccinardi T, Chen X, Katzenellenbogen J. A, Hergenrother P. J, Minutolo F, ChemMedChem. 2015; 1892–1900. [2] Venskutonyté R, Elbing K, Lindkvist-Petersson K, Methods Mol Biol. 2018; 1713, 1–13. [3] Hansen J.H, Elbing K, Thompson J.R, Malmstadt N, Lindkvist-Petersson K, Chem. Commun. 2015; 51, 2316–2319

Watermelon: setup and validation of an in silico fragment-based approach

We present a new computational approach, named Watermelon, designed for the development of pharmacophore models based on receptor structures. The methodology involves the sampling of potential hotspots for ligand interactions within a protein target’s binding site, utilising molecular fragments as probes. By employing docking and molecular dynamics (MD) simulations, the most significant interactions formed by these probes within distinct regions of the binding site are identified. These interactions are subsequently transformed into pharmacophore features that delineates key anchoring sites for potential ligands. The reliability of the approach was experimentally validated using the monoacylglycerol lipase (MAGL) enzyme. The generated pharmacophore model captured features representing ligand-MAGL interactions observed in various X-ray co-crystal structures and was employed to screen a database of commercially available compounds, in combination with consensus docking and MD simulations. The screening successfully identified two new MAGL inhibitors with micromolar potency, thus confirming the reliability of the Watermelon approach