The botanical component p-hydroxycinnamic acid suppresses the growth and bone metastatic activity of human prostate cancer PC-3 cells in vitro

Role of Ubiquitination and Epigenetics in the Regulation of AhR Signaling in Carcinogenesis and Metastasis: "Albatross around the Neck" or "Blessing in Disguise"

The molecular mechanisms and signal transduction cascades evoked by the activation of aryl hydrocarbon receptor (AhR) are becoming increasingly understandable. AhR is a ligand-activated transcriptional factor that integrates environmental, dietary and metabolic cues for the pleiotropic regulation of a wide variety of mechanisms. AhR mediates transcriptional programming in a ligand-specific, context-specific and cell-type-specific manner. Pioneering cutting-edge research works have provided fascinating new insights into the mechanistic role of AhR-driven downstream signaling in a wide variety of cancers. AhR ligands derived from food, environmental contaminants and intestinal microbiota strategically activated AhR signaling and regulated multiple stages of cancer. Although AhR has classically been viewed and characterized as a ligand-regulated transcriptional factor, its role as a ubiquitin ligase is fascinating. Accordingly, recent evidence has paradigmatically shifted our understanding and urged researchers to drill down deep into these novel and clinically valuable facets of AhR biology. Our rapidly increasing realization related to AhR-mediated regulation of the ubiquitination and proteasomal degradation of different proteins has started to scratch the surface of intriguing mechanisms. Furthermore, AhR and epigenome dynamics have shown previously unprecedented complexity during multiple stages of cancer progression. AhR not only transcriptionally regulated epigenetic-associated molecules, but also worked with epigenetic-modifying enzymes during cancer progression. In this review, we have summarized the findings obtained not only from cell-culture studies, but also from animal models. Different clinical trials are currently being conducted using AhR inhibitors and PD-1 inhibitors (Pembrolizumab and nivolumab), which confirm the linchpin role of AhR-related mechanistic details in cancer progression. Therefore, further studies are required to develop a better comprehension of the many-sided and "diametrically opposed" roles of AhR in the regulation of carcinogenesis and metastatic spread of cancer cells to the secondary organs.

CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC ACIDS IN THE FLOWERING SHOOTS OF SOME Vitex L. SPECIES

Introduction. The genus Vitex L. counts more than 200 species of shrubs and trees common to subtropical areas of the Earth. Only fruits of Vitex agnus-castus L. are used in official medicine. The aim of our study was to perform the chromatographic analysis of carboxylic acids in the flowering shoots of three Vitex representatives under their cultivation in Ukraine. Materials and Methods. Gas chromatography with mass spectrometry (GC/MS) was applied for the analysis of composition and contents of carboxylic acids in the Vitex agnus-castus L., Vitex negundo L. and Vitex negundo var. cannabifolia (Siebold & Zucc.) Hand.-Mazz. flowering shoots. Results and Discussion. The Vitex agnus-castus raw material contained the most significant amount of short-chained aliphatic acids (2454 mg/kg). Malonic, oxalic, citric, and malic acids noticeably prevailed in all the raw materials. The largest amount of aromatic acids was found in the Vitex negundo var. cannabifolia (3926 mg/kg) flowering shoots. p-Hydroxybenzoic acid dominated among the aromatic acids in the plant raw materials of all species. The most noticeable total content of unsaturated fatty acids was in the Vitex negundo var. cannabifolia (4793 mg/kg). Conclusions. To summarize the contents of valuable carboxylic acids, the obtained results provide the evidence for the development and further pharmacological study of herbal preparations from the flowering shoots of three Vitex species.

The marine factor 3,5-dihydroxy-4-methoxybenzyl alcohol suppresses growth, migration and invasion and stimulates death of metastatic human prostate cancer cells: targeting diverse signaling processes

Prostate cancer is metastatic cancer and is the second leading cause of cancer-related death in men. It is needed to develop more effective treatment for metastatic prostate cancer. The present study investigates whether the novel factor 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA), which was isolated from marine oyster, suppresses the activity of metastatic human prostate cancer PC-3 or DU-145 cells. Culture of DHMBA (1 or 10 µM) suppressed colony formation and growth of PC-3 or DU-145 cells in vitro. Suppressive effects of DHMBA on cell proliferation were not occurred by culturing with intracellular signaling inhibitors. Mechanistically, DHMBA (10 µM) reduced the levels of key proteins linked to promotion of cell growth, including Ras, PI3K, Akt, MAPK, and mTOR in PC-3 cells. Interestingly, DHMBA increased the levels of cancer suppressor p53, p21, Rb, and regucalcin. Moreover, culture of DHMBA simulated the death of PC-3 and DU-145 cells. This effect was implicated to caspase-3 activation in cells. Interestingly, the effects of DHMBA on cell proliferation and death were blocked by culturing with an inhibitor of aryl hydrocarbon receptor linked to transcriptional regulation. Furthermore, culture of DHMBA inhibited production of reactive oxygen species in PC-3 or DU-145 cells. Of note, DHMBA blocked migration and invasion by diminishing their related protein levels, including NF-κB 65, caveolin-1 and integrin β1. The novel marine factor DHMBA was demonstrated to suppress metastatic prostate cancer cells via targeting diverse signaling pathways. This study may provide a new strategy for prostate cancer therapy with DHMBA.