Cancer cells are particularly vulnerable to treatments impairing redox homeostasis. Reactive oxygen species (ROS) can indeed play an important role in the initiation and progression of cancer, and advanced stage tumors frequently exhibit high basal levels of ROS that stimulate cell proliferation and promote genetic instability. In addition, an inverse correlation between histological grade and antioxidant enzyme activities is frequently observed in human tumors, further supporting the existence of a redox dysregulation in cancer cells. This biochemical property can be exploited by using redox-modulating compounds, which represent an interesting approach to induce cancer cell death. Thus, we have developed a new strategy based on the use of pharmacologic concentrations of ascorbate and redox-active quinones. Ascorbate-driven quinone redox cycling leads to ROS formation and provokes an oxidative stress that preferentially kills cancer cells and spares healthy tissues. Cancer cell death occurs through necrosis and the underlying mechanism implies an energetic impairment (ATP depletion) that is likely due to glycolysis inhibition. Additional mechanisms that participate to cell death include calcium equilibrium impairment and oxidative cleavage of protein chaperone Hsp90. Given the low systemic toxicity of ascorbate and the impairment of crucial survival pathways when associated with redox-active quinones, these combinations could represent an original approach that could be combined to standard cancer therapy.

Hsp90 is a molecular chaperone involved in the stabilization of many oncoproteins that are required for the acquisition and maintenance of the so-called six major hallmarks of cancer cells. Various strategies have, therefore, been developed to inhibit the chaperone activity of Hsp90 and induce cancer cell death through the destabilization of its client proteins. Among these strategies, we have shown that generation of oxidative stress leads to the cleavage and deactivation of Hsp90. Because cancer cells are often deficient in antioxidant enzymes and exhibit higher basal levels of reactive oxygen species (ROS) than their normal counterparts, inducing a selective oxidative stress may be a promising approach for cancer treatment. Thus, many redox-modulating agents have, therefore, been developed or are undergoing clinical trials and Hsp90 represents a new target for oxidative stress-generating agents. The purpose of this article is to review the current state of knowledge about Hsp90 and the use of oxidative stress-generating agents in cancer treatment. We will illustrate the review with some of our results concerning the effects of oxidative stress on Hsp90 using various oxidative stress-generating systems based on different quinones in combination with a well-known reducing agent (i.e., ascorbate). Our results show that oxidative stress provokes the cleavage of Hsp90 in CML cells, as well as the degradation of its client protein Bcr-Abl and the deactivation of its downstream signaling pathways, namely MAPK and STAT5. Overall, these results highlight the potential interest of using oxidative stress to target Hsp90.

The wide tissue distribution of the adrenergic β3 receptor makes it a potential target for the treatment of multiple pathologies such as diabetes, obesity, depression, overactive bladder (OAB), and cancer. Currently, there is only one drug on the market, mirabegron, approved for the treatment of OAB. In the present study, we have carried out an extensive structure-activity relationship analysis of a series of 41 aryloxypropanolamine compounds based on three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques. This is the first combined comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) study in a series of selective aryloxypropanolamines displaying anti-diabetes and anti-obesity pharmacological profiles. The best CoMFA and CoMSIA models presented values of r²_ncv = 0.993 and 0.984 and values of r²_test = 0.865 and 0.918, respectively. The results obtained were subjected to extensive external validation (q², r², r²_m, etc.) and a final series of compounds was designed and their biological activity was predicted (best pEC₅₀ = 8.561).

A highly efficient one-pot procedure for the synthesis of phenanthridine-1,7,10-triones from acylbenzoquinones and cyclic enaminones is reported. The cycloaddition reactions of these quinones with 1-trimethylsilyloxybutadiene followed by hydrolysis and oxidative processes provide entry to a variety of angucyclinone 5-aza analogues.