A therosclerosis, the principal cause of cardiovascular diseases (CVDs), is a process that involves a complex interplay among different factors and cell types, including cells of the immune system (T cells, B cells, natural killer cells, monocytes/macrophages, dendritic cells) and cells of the vessel wall (endothelial cells [ECs], vascular smooth muscle cells [VSMCs]). The atherogenic process evolves in different stages, starting from inflammatory endothelial activation/ dysfunction and resulting in plaque vulnerability and rupture. Vitamin D deficiency affects almost 50% of the population worldwide. It has been suggested that this pandemic might contribute to the worldwide increased prevalence of CVD. 9-11Several mechanisms have been proposed to account for this inverse relationship. In addition to its effects exerted on numerous tissues and organs that indirectly participate in the atherosclerosis, vitamin D is directly involved in this systemic inflammatory process.12,13 Vitamin D receptors (VDRs) are present in all cells implicated in atherosclerosis, including ECs, VSMCs, and immune cells. Vitamin D appears to regulate a wide range of physiological and pathological processes like vascular cell growth, migration, and differentiation; immune response modulation; cytokine expression; and inflammatory and fibrotic pathways, all of which play a crucial role, starting from the early stage of endothelial activation/dysfunction to the later stages of the plaque vulnerability and rupture.In this review, we provide current data on the effects of vitamin D on cells directly implicated in atherosclerosis such as ECs, VSMCs, and immune cells (lymphocytes, monocytes, macrophages, etc) with a focus on the underlying molecular mechanisms, which are still largely unknown. We also summarize reports related to the favorable (antiatherogenic) actions of vitamin D in tissues and organs that indirectly participate in the atherogenic process. Finally, we critically discuss clinical studies to assess the protective role of vitamin D and the efficacy of vitamin D and VDR agonists in CVD. Because a comprehensive background is a prerequisite for further discussions of vitamin D-induced effects, we provide a brief description of vitamin D metabolism and mechanism of action. Vitamin D Metabolism and Mechanism of ActionVitamin D is a steroid hormone that comes in 2 forms that differ chemically in their side chain, D 2 and D 3 (Figure 1). Either produced in the skin (D 3 ) from 7-dehydrocholesterol by exposure to ultraviolet-B light or ingested with foods of plant or animal origin (D 2 and D 3 , respectively), vitamin D is biologically inert and requires 2 hydroxylations to form its active metabolite. 10 The first hydroxylation is constitutive and takes place in the liver by vitamin D-25-hydroxylase to form 25(OH)D. The second hydroxylation is catalyzed by 25(OH) D-1aOHase (CYP27B1) to form the biologically active form of vitamin D, 1,25(OH) 2 D (calcitriol; see Figure 1). This latter 1a-hydroxylation of 25(OH)D takes place in most tiss...
SUMMARY Pharmacologic targeting of components of ERK signaling in ERK-dependent tumors is often limited by adaptive resistance, frequently mediated by feedback-activation of RTK signaling and rebound of ERK activity. Here, we show that combinatorial pharmacologic targeting of ERK signaling and the SHP2 phosphatase prevents adaptive resistance in defined subsets of ERK-dependent tumors. In each tumor that was sensitive to combined treatment, p(Y542) SHP2 induction was observed in response to ERK signaling inhibition. The strategy was broadly effective in TNBC models and tumors with RAS mutations at G12, whereas tumors with RAS(G13D) or RAS(Q61X) mutations were resistant. In addition, we identified a subset of BRAF(V600E) tumors that were resistant to the combined treatment, in which FGFR was found to drive feedback-induced RAS activation, independently of SHP2. Thus, we identify molecular determinants of response to combined ERK signaling and SHP2 inhibition in ERK-dependent tumors.
Current data support the direct or indirect induction of ER stress response by advanced glycation end products or advanced glycation end product precursors in the pathogenesis of metabolic diseases. Inhibitors of advanced glycation acting as potent ER stress modulators with beneficial effects in restoring ER homeostasis and adjusting physiological unfolded protein response level present an emerging therapeutic approach with significant applications, especially in the context of metabolic dysfunction.
The polycystins PC1 and PC2 are emerging as major players in mechanotransduction, a process that influences all steps of the invasion/metastasis cascade. We hypothesized that PC1 and PC2 facilitate cancer aggressiveness. Immunoblotting, RT-PCR, semi-quantitative and quantitative real-time PCR and FACS analyses were employed to investigate the effect of polycystin overexpression in colorectal cancer (CRC) cells. The impact of PC1 inhibition on cancer-cell proliferation was evaluated through an MTT assay. In vitro data were analyzed by Student's t-test. HT29 human xenografts were treated with anti-PC1 (extracellular domain) inhibitory antibody and analyzed via immunohistochemistry to determine the in vivo role of PC1 in CRC. Clinical significance was assessed by examining PC1 and PC2 protein expression in CRC patients (immunohistochemistry). In vivo and clinical data were analyzed by non-parametric tests, Kaplan-Meier curves, log-rank test and Cox model. All statistical tests were two-sided. PC1 overexpression promotes epithelial-to-mesenchymal transition (EMT) in HCT116 cells, while PC2 overexpression results in upregulation of the mTOR pathway in SW480 cells. PC1 inhibition causes reduced cell proliferation in CRC cells inducing tumor necrosis and suppressing EMT in HT29 tumor xenografts. In clinical study, PC1 and PC2 overexpression associates with adverse pathological parameters, including invasiveness and mucinous carcinomas. Moreover, PC1 overexpression appears as an independent prognostic factor of reduced recurrence-free survival (HR 5 1.016, p 5 0.03) and lowers overall survival probability, while aberrant PC2 expression predicts poor overall survival (p 5 0.0468). These results support, for the first time, a direct link between mechanosensing polycystins (PC1 and PC2) and CRC progression.Invasion and metastasis are responsible for 90% of cancerassociated mortality. While the role of biochemical signals in invasion and metastasis is well established, growing evidence reveals that mechanical signals also regulate cancer-cell
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