New antiglioma zwitterionic pronucleotides with an FdUMP framework

Prodrugs of Nucleoside 5'-Monophosphate Analogues: Overview of the Recent Literature Concerning their Synthesis and Applications

Nucleoside analogues are widely used as anti-infectious and antitumoral agents. However, their clinical use may face limitations associated with their physicochemical properties, pharmacokinetic parameters, and/or their peculiar mechanisms of action. Indeed, once inside the cells, nucleoside analogues require to be metabolized into their corresponding (poly-)phosphorylated derivatives, mediated by cellular and/or viral kinases, in order to interfere with nucleic acid biosynthesis. Within this activation process, the first-phosphorylation step is often the limiting one and to overcome this limitation, numerous prodrug approaches have been proposed. Herein, we will focus on recent literature data (from 2015 and onwards) related to new prodrug strategies, the development of original synthetic approaches and novel applications of nucleotide prodrugs (namely pronucleotides) leading to the intracellular delivery of 5'-monophosphate nucleoside analogues.

COXIBs and 2,5-dimethylcelecoxib counteract the hyperactivated Wnt/β-catenin pathway and COX-2/PGE2/EP4 signaling in glioblastoma cells

BACKGROUND

Glioblastoma (GBM) is the deadliest and the most common primary brain tumor in adults. The invasiveness and proliferation of GBM cells can be decreased through the inhibition of Wnt/β-catenin pathway. In this regard, celecoxib is a promising agent, but other COXIBs and 2,5-dimethylcelecoxib (2,5-DMC) await elucidation. Thus, the aim of this study was to analyze the impact of celecoxib, 2,5-DMC, etori-, rofe-, and valdecoxib on GBM cell viability and the activity of Wnt/β-catenin pathway. In addition, the combination of the compounds with temozolomide (TMZ) was also evaluated. Cell cycle distribution and apoptosis, MGMT methylation level, COX-2 and PGE2 EP4 protein levels were also determined in order to better understand the molecular mechanisms exerted by these compounds and to find out which of them can serve best in GBM therapy.

METHODS

Celecoxib, 2,5-DMC, etori-, rofe- and valdecoxib were evaluated using three commercially available and two patient-derived GBM cell lines. Cell viability was analyzed using MTT assay, whereas alterations in MGMT methylation level were determined using MS-HRM method. The impact of COXIBs, in the presence and absence of TMZ, on Wnt pathway was measured on the basis of the expression of β-catenin target genes. Cell cycle distribution and apoptosis analysis were performed using flow cytometry. COX-2 and PGE2 EP4 receptor expression were evaluated using Western blot analysis.

RESULTS

Wnt/β-catenin pathway was attenuated by COXIBs and 2,5-DMC irrespective of the COX-2 expression profile of the treated cells, their MGMT methylation status, or radio/chemoresistance. Celecoxib and 2,5-DMC were the most cytotoxic. Cell cycle distribution was altered, and apoptosis was induced after the treatment with celecoxib, 2,5-DMC, etori- and valdecoxib in T98G cell line. COXIBs and 2,5-DMC did not influence MGMT methylation status, but inhibited COX-2/PGE2/EP4 pathway.

CONCLUSIONS

Not only celecoxib, but also 2,5-DMC, etori-, rofe- and valdecoxib should be further investigated as potential good anti-GBM therapeutics.

H-Phosphonate Chemistry in the Synthesis of Electrically Neutral and Charged Antiviral and Anticancer Pronucleotides

In this review a short account of our work on the synthesis and biological activity of electrically neutral and charged anti-HIV and anticancer pronucleotides, presented on the background of the contemporary research in this area, is given.

Down-regulation of tenascin-C inhibits breast cancer cells development by cell growth, migration, and adhesion impairment

Tenascin-C (TNC) is an extracellular matrix (ECM) glycoprotein that plays an important role in cell proliferation, migration, and tumour invasion in various cancers. TNC is one of the main protein overexpressed in breast cancer, indicating a role for this ECM molecule in cancer pathology. In this study we have evaluated the TNC loss-off-function in breast cancer cells. In our approach, we used dsRNA sharing sequence homology with TNC mRNA, called ATN-RNA. We present the data showing the effects of ATN-RNA in MDA-MB-231 cells both in monolayer and three-dimensional culture. Cells treated with ATN-RNA were analyzed for phenotypic alterations in proliferation, migration, adhesion, cell cycle, multi-caspase activation and the involvement in epithelial to mesenchymal transition (EMT) processes. As complementary analysis the oncogenomic portals were used to assess the clinical implication of TNC expression on breast cancer patient's survival, showing the TNC overexpression associated with a poor survival outcome. Our approach applied first in brain tumors and then in breast cancer cell lines reveals that ATN-RNA significantly diminishes the cell proliferation, migration and additionally, reverses the mesenchymal cells phenotype to the epithelial one. Thus, TNC could be considered as the universal target in different types of tumors, where TNC overexpression is associated with poor prognosis.

Pd-catalyzed asymmetric allylic substitution cascade using α-(pyridin-1-yl)-acetamides formed in situ as nucleophiles

A Pd-catalyzed asymmetric allylic substitution cascade reaction, using α-(pyridin-1-yl)-acetamides (formed in situ) as nucleophiles, has been developed, generating chiral piperidine-containing amino acid derivatives via a one-pot procedure in high yields and with up to 96% ee. The products can be easily converted into potential bioactive compounds, unnatural chiral amino acids and dipeptides.