AI Based Discovery of a New AKR1C3 Inhibitor for Anticancer Applications.

AKR1C3 is an upregulated enzyme in prostate and other cancers; in addition to regulating hormone synthesis, this enzyme is thought to play a role in the aggressiveness of tumors and in the defense against drugs. We here used an unbiased method to discover new potent AKR1C3 inhibitors: through an AI-based virtual drug screen, compound 4 was identified as a potent and selective enzymatic inhibitor able to translate this activity into a pronounced antiproliferative effect in the 22RV1 prostate cancer cell model. As other known AKR1C3 inhibitors, compound 4 determined a significantly increased activity of abiraterone, a drug approved for advanced prostate cancer. Compound 4 also showed a synergic effect with doxorubicin in osteosarcoma cell lines; specifically, the effect is correlated with AKR1C3 expression. In this research work, therefore, the use of AI allowed the identification of a new structure as an AKR1C3 inhibitor and its potential to enhance the effect of chemotherapeutics.

Extraction, purification and in vitro assessment of the antioxidant and anti-inflammatory activity of policosanols from non-psychoactive Cannabis sativa L.

Policosanols (PCs) are bioactive compounds extracted from different natural waxes. In this work, the purification, characterization and assessment of the antioxidant and anti-inflammatory activity was carried out on PCs from an innovative source, i.e. a waxy material from supercritical-fluid extraction (SFE) of non-psychoactive Cannabis sativa L. (hemp) inflorescences. Starting from this material, PCs were obtained by microwave-assisted trans-esterification and hydrolysis, followed by preparative liquid chromatography under normal phase conditions. The purified product was characterized using high-performance liquid chromatography (HPLC) with an evaporative light scattering detector (ELSD). In vitro cell-free and cell-based antioxidant and anti-inflammatory assays were then performed to assess their bioactivity. HPLC-ELSED analysis of the purified mixture from hemp wax revealed C26OH and C28OH as the main compounds. In vitro assays indicated an inhibition of intracellular reactive oxygen species (ROS) production, a reduction of nuclear factor kappa B (NF-κB) activation and of the activity of the neutrophil elastase. Immunoblotting assays allowed us to hypothesize the mechanism of action of the compounds of interest, given the higher levels of MAPK-activated protein kinase 2 (MK2) and heme oxygenase-1 (HO-1) protein expression in the PC pretreated HaCaT cells. In conclusion, even if more research is needed to unveil other molecular mechanisms involved in hemp PC activity, the results of this work suggest that these compounds may have potential for use in oxinflammation processes.

Structure-guided optimization of 3-hydroxybenzoisoxazole derivatives as inhibitors of Aldo-keto reductase 1C3 (AKR1C3) to target prostate cancer.

AKR1C3 is an enzyme that is overexpressed in several types of radiotherapy- and chemotherapy-resistant cancers. Despite AKR1C3 is a validated target for drug development, no inhibitor has been approved for clinical use. In this manuscript, we describe our study of a new series of potent AKR1C3-targeting 3-hydroxybenzoisoxazole based inhibitors that display high selectivity over the AKR1C2 isoform and low micromolar activity in inhibiting 22Rv1 prostate cancer cell proliferation. In silico studies suggested proper substituents to increase compound potency and provided with a mechanistic explanation that could clarify their different activity, later confirmed by X-ray crystallography. Both the in-silico studies and the crystallographic data highlight the importance of 90° rotation around the single bond of the biphenyl group, in ensuring that the inhibitor can adopt the optimal binding mode within the active pocket. The p-biphenyls that bear the meta-methoxy, and the ortho- and meta-trifluoromethyl substituents (in compounds 6a, 6e and 6f respectively) proved to be the best contributors to cellular potency as they provided the best IC50 values in series (2.3, 2.0 and 2.4 µM respectively) and showed no toxicity towards human MRC-5 cells. Co-treatment with scalar dilutions of either compound 6 or 6e and the clinically used drug abiraterone led to a significant reduction in cell proliferation, and thus confirmed that treatment with both CYP171A1-and AKR1C3-targeting compounds possess the potential to intervene in key steps in the steroidogenic pathway. Taken together, the novel compounds display desirable biochemical potency and cellular target inhibition as well as good in-vitro ADME properties, which highlight their potential for further preclinical studies.