A Comprehensive Overview of the Developments of Cdc25 Phosphatase Inhibitors.

Cdc25 phosphatases have been considered promising targets for anticancer development due to the correlation of their overexpression with a wide variety of cancers. In the last two decades, the interest in this subject has considerably increased and many publications have been launched concerning this issue. An overview is constructed based on data analysis of the results of the previous publications covering the years from 1992 to 2021. Thus, the main objective of the current review is to report the chemical structures of Cdc25s inhibitors and answer the question, how to design an inhibitor with better efficacy and lower toxicity?

Synthesis, biological evaluation and molecular modeling studies on novel quinonoid inhibitors of CDC25 phosphatases.

The cell division cycle 25 phosphatases (CDC25A, B, and C; E.C. 3.1.3.48) are key regulator of the cell cycle in human cells. Their aberrant expression has been associated with the insurgence and development of various types of cancer, and with a poor clinical prognosis. Therefore, CDC25 phosphatases are a valuable target for the development of small molecule inhibitors of therapeutic relevance. Here, we used an integrated strategy mixing organic chemistry with biological investigation and molecular modeling to study novel quinonoid derivatives as CDC25 inhibitors. The most promising molecules proved to inhibit CDC25 isoforms at single digit micromolar concentration, becoming valuable tools in chemical biology investigations and profitable leads for further optimization. [Formula: see text].

Screening of indeno[1,2-b]indoloquinones by MALDI-MS: a new set of potential CDC25 phosphatase inhibitors brought to light.

Quinones and quinones-like compounds are potential candidates for the inhibition of CDC25 phosphatases. The combination of MALDI-MS analyses and biological studies was used to develop a rapid screening of a targeted library of indeno[1,2-b]indoloquinone derivatives. The screening protocol using MALDI-TOFMS and MALDI-FTICRMS highlighted four new promising candidates. Biological investigations showed that only compounds 5c-f inhibited CDC25A and -C phosphatases, with IC50 values around the micromolar range. The direct use of a screening method based on MALDI-MS technology allowed achieving fast scaffold identification of a new class of potent inhibitors of CDC25 phosphatases. These four molecules appeared as novel molecules of a new class of CDC25 inhibitors. Assessment of 5c-e in an MRC5 proliferation assay provided an early indicator of toxicity to mammalian cells. Compound 5d seems the most promising hit for developing new CDC25 inhibitors.

The Redox Cycler Plasmodione Is a Fast-Acting Antimalarial Lead Compound with Pronounced Activity against Sexual and Early Asexual Blood-Stage Parasites.

Previously, we presented the chemical design of a promising series of antimalarial agents, 3-[substituted-benzyl]-menadiones, with potent in vitro and in vivo activities. Ongoing studies on the mode of action of antimalarial 3-[substituted-benzyl]-menadiones revealed that these agents disturb the redox balance of the parasitized erythrocyte by acting as redox cyclers-a strategy that is broadly recognized for the development of new antimalarial agents. Here we report a detailed parasitological characterization of the in vitro activity profile of the lead compound 3-[4-(trifluoromethyl)benzyl]-menadione 1c (henceforth called plasmodione) against intraerythrocytic stages of the human malaria parasite Plasmodium falciparum We show that plasmodione acts rapidly against asexual blood stages, thereby disrupting the clinically relevant intraerythrocytic life cycle of the parasite, and furthermore has potent activity against early gametocytes. The lead's antiplasmodial activity was unaffected by the most common mechanisms of resistance to clinically used antimalarials. Moreover, plasmodione has a low potential to induce drug resistance and a high killing speed, as observed by culturing parasites under continuous drug pressure. Drug interactions with licensed antimalarial drugs were also established using the fixed-ratio isobologram method. Initial toxicological profiling suggests that plasmodione is a safe agent for possible human use. Our studies identify plasmodione as a promising antimalarial lead compound and strongly support the future development of redox-active benzylmenadiones as antimalarial agents.

2-(Thienothiazolylimino)-1,3-thiazolidin-4-ones inhibit cell division cycle 25 A phosphatase.

Cell division cycle dual phosphatases (CDC25) are essential enzymes that regulate cell progression in cell cycle. Three isoforms exist as CDC25A, B and C. Over-expression of each CDC25 enzyme is found in cancers of diverse origins. Thiazolidinone derivatives have been reported to display anti-proliferative activities, bactericidal activities and to reduce inflammation process. New 2-(thienothiazolylimino)-1,3-thiazolidin-4-ones were synthesized and evaluated as inhibitors of CDC25 phosphatase. Among the molecules tested, compound 6 inhibited CDC25A with an IC50 estimated at 6.2±1.0µM. The binding of thiazolidinone derivative 6 onto CDC25A protein was reversible. In cellulo, compound 6 treatment led to MCF7 and MDA-MB-231 cell growth arrest. To our knowledge, it is the first time that such 4-thiazolidinone derivatives are characterized as CDC25 potential inhibitor.

A novel coumarin-quinone derivative SV37 inhibits CDC25 phosphatases, impairs proliferation, and induces cell death.

Cell division cycle (CDC) 25 proteins are key phosphatases regulating cell cycle transition and proliferation by regulating CDK/cyclin complexes. Overexpression of these enzymes is frequently observed in cancer and is related to aggressiveness, high-grade tumors and poor prognosis. Thus, targeting CDC25 by compounds, able to inhibit their activity, appears a good therapeutic approach. Here, we describe the synthesis of a new inhibitor (SV37) whose structure is based on both coumarin and quinone moieties. An analytical in vitro approach shows that this compound efficiently inhibits all three purified human CDC25 isoforms (IC50 1-9 µM) in a mixed-type mode. Moreover, SV37 inhibits growth of breast cancer cell lines. In MDA-MB-231 cells, reactive oxygen species generation is followed by pCDK accumulation, a mark of CDC25 dysfunction. Eventually, SV37 treatment leads to activation of apoptosis and DNA cleavage, underlining the potential of this new type of coumarin-quinone structure.

Plumbagin modulates leukemia cell redox status.

Plumbagin is a plant naphtoquinone exerting anti-cancer properties including apoptotic cell death induction and generation of reactive oxygen species (ROS). The aim of this study was to elucidate parameters explaining the differential leukemia cell sensitivity towards this compound. Among several leukemia cell lines, U937 monocytic leukemia cells appeared more sensitive to plumbagin treatment in terms of cytotoxicity and level of apoptotic cell death compared to more resistant Raji Burkitt lymphoma cells. Moreover, U937 cells exhibited a ten-fold higher ROS production compared to Raji. Neither differential incorporation, nor efflux of plumbagin was detected. Pre-treatment with thiol-containing antioxidants prevented ROS production and subsequent induction of cell death by apoptosis whereas non-thiol-containing antioxidants remained ineffective in both cellular models. We conclude that the anticancer potential of plumbagin is driven by pro-oxidant activities related to the cellular thiolstat.

Genotoxic stress modulates CDC25C phosphatase alternative splicing in human breast cancer cell lines.

CDC25 (cell division cycle 25) phosphatases are essential for cell cycle control under normal conditions and in response to DNA damage. They are represented by three isoforms, CDC25A, B and C, each of them being submitted to an alternative splicing mechanism. Alternative splicing of many genes is affected in response to genotoxic stress, but the impact of such a stress on CDC25 splicing has never been investigated. In this study, we demonstrate that genotoxic agents (doxorubicin, camptothecin, etoposide and cisplatin), alter the balance between CDC25C splice variants in human breast cancer cell lines both at the mRNA and protein levels. This modulation occurs during the response to moderate, sub-lethal DNA damage. Our results also suggest that the CDC25C splice variants expression shift induced by a genotoxic stress is dependent on the ATM/ATR signaling but not on p53. This study highlights the modulation of CDC25C alternative splicing as an additional regulatory event involved in cellular response to DNA damage in breast cancer cells.

Aurones: interesting natural and synthetic compounds with emerging biological potential.

Aurones [2-benzylidenebenzofuran-3(2H)-ones] are either natural or synthetic compounds, belonging to the flavonoid family. They are isomeric to flavones and provide a bright yellow color to the plants in which they occur. Today, a literature survey indicates that the related flavonoids have been studied not only for their physiological properties and effects on Nature, but also for their therapeutic potential. Aurones are recently attracting the interest of an increasing number of research groups, and, since the last review, some interesting advances have been made in understanding the aurones. In this review, we report the recent advances made on the synthetic routes towards aurones. We also highlight their activity in different biological areas, as well as applied genetic plant modifications to produce these colored compounds. Their synthesis, structure-activity relationships and the importance of the substitution pattern will also be mentioned. Finally, some aspects regarding the possible development of aurones will be discussed briefly.

Protection of CDC25 phosphatases against oxidative stress in breast cancer cells: evaluation of the implication of the thioredoxin system.

Reactive oxygen species regulate protein functionality. Cell cycle CDC25 phosphatases are targets of such oxidative regulation in vitro. We sought to evaluate if a thioredoxin (trx)-dependent redox regulation of CDC25 exists in cancer cells. For that purpose, we used MCF7 and MDA-MB 231 breast cancer cells, which express trx1 differentially, together with two trx/thioredoxin reductase (trxR) inhibitors, Auranofin and Acrolein. Auranofin could induce a full trxR inhibition associated with ROS production in both cell lines. Acrolein could provoke similar effects only in MDA-MB 231 cells with a low trx1 expression. Simultaneous trx1 oxidation and trxR inactivation occurred only in the presence of Acrolein and resulted in a G2-M cell cycle arrest, without full CDC25 inhibition in MDA-MB 231 cells. Our data suggest that the maintenance of CDC25 activity does not fully rely on the trx system in breast cancer cells, even in the presence of a major oxidative stress.

Coumarin polysulfides inhibit cell growth and induce apoptosis in HCT116 colon cancer cells.

Coumarins and coumarin derivatives as well as diallyl polysulfides are well known as anticancer drugs. In order to find new drugs with anticancer activities, we combined coumarins with polysulfides in the form of di-coumarin polysulfides. These novel compounds were tested in the HCT116 colorectal cancer cell line. It turned out that they reduced cell viability of cancer cells in a time and concentration dependent manner. Cells tested with these coumarin polysulfides accumulate in the G(2)/M phase of the cell cycle and finally they go into apoptosis. A decrease in bcl-2 level, and increase in the level of bax, cytochrome c release into the cytosol, cleavage of caspase 3/7and PARP suggested that coumarin polysulfides induced the intrinsic pathway of apoptosis. Comparison of these new coumarin compounds with the well known diallyl polysulfides revealed that the coumarin disulfides were more active than the corresponding diallyl disulfides. The activities of the coumarin tetrasulfides and the corresponding diallyl tetrasulfides are similar. The novel coumarin compounds regulated the phosphatase activity of the cell cycle regulating cdc25 family members, indicating that these phosphatases are implicated in the induction of cell cycle arrest and possibly in apoptosis induction as well. In addition, coumarin polysulfides also down-regulated the level of cdc25C, which also contributed to the arrest in the G(2)-phase of the cell cycle.

Control of oxidative posttranslational cysteine modifications: from intricate chemistry to widespread biological and medical applications.

Cysteine residues in proteins and enzymes often fulfill rather important roles, particularly in the context of cellular signaling, protein-protein interactions, substrate and metal binding, and catalysis. At the same time, some of the most active cysteine residues are also quite sensitive toward (oxidative) modification. S-Thiolation, S-nitrosation, and disulfide bond and sulfenic acid formation are processes which occur frequently inside the cell and regulate the function and activity of many proteins and enzymes. During oxidative stress, such modifications trigger, among others, antioxidant responses and cell death. The unique combination of nonredox function on the one hand and participation in redox signaling and control on the other has placed many cysteine proteins at the center of drug design and pesticide development. Research during the past decade has identified a range of chemically rather interesting, biologically very active substances that are able to modify cysteine residues in such proteins with huge efficiency, yet also considerable selectivity. These agents are often based on natural products and range from simple disulfides to complex polysulfanes, tetrahydrothienopyridines, α,ß -unsaturated disulfides, thiuramdisulfides, and 1,2-dithiole-3-thiones. At the same time, inhibition of enzymes responsible for posttranslational cysteine modifications (and their removal) has become an important area of innovative drug research. Such investigations into the control of the cellular thiolstat by thiol-selective agents cross many disciplines and are often far from trivial.

Differential expression of CDC25 phosphatases splice variants in human breast cancer cells.

BACKGROUND: CDC25 phosphatases control cell cycle progression by activating cyclin dependent kinases. The three CDC25 isoforms encoding genes are submitted to alternative splicing events which generate at least two variants for CDC25A and five for both CDC25B and CDC25C. An over-expression of CDC25 was reported in several types of cancer, including breast cancer, and is often associated with a poor prognosis. Nevertheless, most of the previous studies did not address the expression of CDC25 splice variants. Here, we evaluated CDC25 spliced transcripts expression in anti-cancerous drug-sensitive and resistant breast cancer cell lines in order to identify potential breast cancer biomarkers. METHODS: CDC25 splice variants mRNA levels were evaluated by semi-quantitative RT-PCR and by an original real-time RT-PCR assay. RESULTS: CDC25 spliced transcripts are differentially expressed in the breast cancer cell lines studied. An up-regulation of CDC25A2 variant and an increase of the CDC25C5/C1 ratio are associated to the multidrug-resistance in VCREMS and DOXOR breast cancer cells, compared to their sensitive counterpart cell line MCF-7. Additionally, CDC25B2 transcript is exclusively over-expressed in VCREMS resistant cells and could therefore be involved in the development of certain type of drug resistance. CONCLUSIONS: CDC25 splice variants could represent interesting potential breast cancer prognostic biomarkers.

Antiproliferative effect of natural tetrasulfides in human breast cancer cells is mediated through the inhibition of the cell division cycle 25 phosphatases.

For many years, in vitro and in vivo studies have reported that organosulfur compounds (OSCs), naturally found in Allium vegetables, are able to suppress the proliferation of various tumor cells. In spite of recent advances, the specific molecular mechanisms involved in OSC activity are still unclear. Considering the antiproliferative effects observed in cancer cells, we postulated that OSCs might target the cell division cycle (Cdc) 25 phosphatases which are crucial enzymes of the cell cycle. Our findings suggest phosphatases Cdc25 as possible targets of naturally occuring polysulfides contributing to their anticancer properties. We report on the inhibitory activity of tetrasulfides occurring naturally in garlic and onion towards the human Cdc25 phosphatases. Diallyl- and dipropyltetrasulfides have emerged as interesting irreversible inhibitors of the Cdc25 isoforms A and C in vitro. Furthermore, growth of both sensitive (MCF-7) and resistant (Vcr-R) human breast carcinoma cells was significantly decreased by these tetrasulfides. The observed antiproliferative effect appeared to be associated with a G2-M cell cycle arrest.

Functional genomics towards personalized healthcare and systems medicine.

The 5th Biologie Prospective Santorini Conference explored the themes of systems biology, nutrigenomics and pharmacogenomics, all of which are related to personalized health, personalized therapy and personalized medicine. The conference started with a satellite meeting on genome-wide scan studies where the need for simplified models, the quality of the phenotypes and the input of epigenetics were dominant remarks. All of the omics approaches were then applied during the 3 days' sessions to multifactorial diseases (e.g., diabetes, atherosclerosis, cancer and inflammation) and often focused on gene-gene and gene-environment interactions. Afterwards, a fundamental session on drug metabolism, theranostics and pharmacogenetics and their practical aspects showed that the translation to clinical practice is finally happening although much slower than expected.

Synthesis and biological evaluation of novel coumarin-based inhibitors of Cdc25 phosphatases.

The cell division cycle 25 (Cdc25) family of proteins are dual specificity phosphatases that activate cyclin-dependent kinase (CDK) complexes, which in turn regulate progression through the cell division cycle. Overexpression of Cdc25 proteins has been reported in a wide variety of cancers; their inhibition may thus represent a novel approach for the development of anticancer therapeutics. Herein we report new coumarin-based scaffolds endowed with a selective inhibition against Cdc25A and Cdc25C, being 6a and 6d the most efficient inhibitors and worthy of further investigation as anticancer agents.

eRF3a/GSPT1 12-GGC allele increases the susceptibility for breast cancer development.

It is now widely recognized that translation factors are involved in cancer development and that components of the translation machinery that are deregulated in cancer cells may become targets for cancer therapy. The eukaryotic Release Factor 3 (eRF3) is a GTPase that associates with eRF1 in a complex that mediates translation termination. eRF3a/GSPT1 first exon contains a (GGC)n expansion coding for proteins with different N-terminal extremities. Herein we show that the longer allele (12-GGC) is present in 5.1% (7/137) of the breast cancer patients analysed and is absent in the control population (0/135), corresponding to an increased risk for cancer development, as revealed by Odds Ratio analysis. mRNA quantification suggests that patients with the 12-GGC allele overexpress eRF3a/GSPT1 in tumor tissues relative to the normal adjacent tissues. However, using an in vivo assay for translation termination in HEK293 cells, we do not detect any difference in the activity of the eRF3a proteins encoded by the various eRF3a/GSPT1 alleles. Although the connection between the presence of eRF3a/GSPT1 12-GGC allele and tumorigenesis is still unknown, our data suggest that the presence of the 12-GGC allele provides a potential novel risk marker for various types of cancer.

Synthesis and antioxidant potential of novel synthetic benzophenone analogues.

Considering that oxidative stress is strongly implicated in the toxicity of chemotherapy, much effort is focused on the research of diverse antioxidants as protective agents. An efficient synthesis of three novel benzophenones containing 1,3-thiazol moiety (6a-c) is described. Their antioxidant power was evaluated in vitro and in three cell lines (the cancerous MCF7 and the non-cancerous hTERT-HME1 mammary cells, and the H9c2 cardiomyoblastic cells). One analogue 5-(2,5-dihydroxybenzoyl)-2(3H)-benzothiazolone (6c), displayed an important antioxidant activity, a low cytotoxicity, and could decrease reactive oxygen species production generated by tert-butyl hydroperoxide (tBHP) in all three cell lines. Interestingly, 6c was able to protect the non-cancerous cells against tBHP-induced death. Further studies are underway to determine its relevance as an adjuvant in oxidative stress inducing chemotherapy.

Apoptosis/necrosis switch in two different cancer cell lines: influence of benzoquinone- and hydrogen peroxide-induced oxidative stress intensity, and glutathione.

Depending on the strength of oxidative stress, cells exhibit proliferative, apoptotic or necrotic responses. We have investigated whether the severity of glutathione (GSH) depletion could determine the type of cell death using 1,4-benzoquinone (BQ) and H(2)O(2) in two different tumor cell lines (human mammary gland carcinoma MCF-7 and rat hepatoma H5-6). BQ-treated surviving cells showed an increase in GSH, but no detectable oxidized glutathione (GSSG) nor reactive oxygen species (ROS) augmentation. Alternatively, H(2)O(2) depressed GSH. BQ induced mostly apoptosis, up to 90% cell elimination, while necrosis was prominent in H(2)O(2)-treated cultures. The resistance of BQ-treated cells to necrosis could be due to increased cellular GSH and formation of BQ-GSH conjugates which are less toxic than free BQ, minimal toxicity being provided by GS4-BHQ. This ability of certain cancer cells to tightly keep the apoptotic pathway may have therapeutic applications for oxidation-based drugs.