Small Molecules as Modulators of Different Targets Involved in Tumor Progression

Tumor is a lesion that may be formed by an abnormal growth of neoplastic cells. Many factors increase the risk of cancer and different targets are involved in tumor progression. Within this thesis, we have addressed two different biological targets, independently connected with tumor formation, e.g. Hsp90 and androgen receptor. The ATP-dependent chaperone Hsp90 is responsible for the conformational maturation and the renaturation of proteins. “Client” proteins are associated with the cancer hallmarks, as cell proliferation and tumor progression. Consequently, Hsp90 has evolved into promising anticancer target. Over the past decade, radicicol has been identified as potential anticancer agent targeting Hsp90, but it is not active in vivo. With that aim of obtaining radicicol-related derivatives, we developed the design and synthesis of new chalcones analogs. Chalcones, which are abundant in edible plants, own a diverse array of pharmacological activities and are considered a versatile scaffold for drug design. Antiproliferative assays and western blot analysis on the new compounds showed that some of those display an interesting cytotoxic effect and the ability to modulate Hsp90 client proteins expression. Androgen Receptor (AR) hypersensitivity plays crucial role in prostate cancer, which progression is stimulated by androgens. The therapy consists in a combination of surgical or chemical castration, along with antiandrogens treatment. Casodex® (bicalutamide), is the most widespread antiandrogen used in clinic. However, hormonal therapy is time-limited since many patients develop resistance. Commercially available antiandrogens show a common scaffold, e.g. two substituted aromatic rings linked by a linear or a cyclic spacer. With the aim of obtaining novel pure AR antagonists, we developed a new synthetic methodology, which allowed us to introduce, as linker between two suitably chosen aromatic rings, a triazole moiety. Preliminary data suggest that the herein reported new molecules generally decrease PSA expression, thus confirming their potential AR antagonistic activity.

Discovery and Pharmacological Characterization of a Novel Small Molecule Antagonist of Integrin α4β1: Focus on Antiallergic Activity

Allergy is a common hypersensitivity disorder that affects 15% to 20% of the population and its prevalence is increasing worldwide. Its severity correlates with the degree of eosinophil infiltration into the conjunctiva, which is mediated by chemokines that stimulate the production of adhesion molecules like intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the endothelial cell surface. The α4β1 and α4β7 integrins are expressed in eosinophils and contribute to their activation and infiltration in AC through the binding to VCAM-1 or fibronectin, expressed on vascular endothelial cells. Blockade of α4 integrins might be a therapeutical achievement in allergic eye diseases. DS 70, that show an IC50 in the nanomolar range against α4β1 integrin in Jurkat cells and in the eosinophilic cell line EOL-1. This compound was able to prevent cell adhesion to VCAM-1 and FN in vitro. In a scintillation proximity assay DS70 displaced 125I-FN binding to human α4β1 integrin and, in flow cytometry analysis, it antagonized the binding of a primary antibody to α4β1 integrin expressed on the Jurkat cells surface as well. Furthermore, we analysed also its effects on integrin α4β1 signalling. In an vivo model of allergic conjunctivitis, topical DS70 reduced the clinical aspects of EPR (early phase reaction) and LPR (late phase reaction), by reducing clinical score, eosinophil accumulation, mRNA levels of cytochines and chemochines pro-inflammatory and the conjunctival expression of α4 integrin. In conclusion, DS70 seems a novel antiallergic ocular agent that has significant effects on both early and late phases of ocular allergy.