Mechanisms of resistance to vitamin D action in human cancer cells

El pdf es la versión post-print.Initial clinical trials in cancer patients with vitamin D compounds have shown acceptable toxicity but low activity. A number of mechanisms responsible for resistance to their action in cancer cells have been recently reported. They include reduced intracellular availability of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D], loss of vitamin D receptor (VDR) expression and deregulation of transcription corepressors that modulate VDR action. Here, we summarize the data in the literature on the altered activity of the enzymes (CYP27B1, CYP24A1) that controls 1,25(OH)2D levels, the repression of VDR by the transcription factor Snail1 and the overexpression of several VDR corepressors (NCoR, SMRT) in cancer cells. A better understanding of these processes must contribute to improved protocols for the clinical use of vitamin D compounds.The work in authors’ laboratory is supported by the Ministerio de Ciencia e Innovación of Spain, Comunidad de Madrid and European Union.Peer Reviewe

The transcription factors Snail1 and Snail2 repress vitamin D receptor during colon cancer progression

El pdf es el manuscrito de autor.Vitamin D receptor (VDR) mediates the antitumoral action of the active vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). However, VDR expression is lost during colon cancer progression, possibly causing unresponsiveness to 1,25(OH)2D3. Although several mechanisms responsible for resistance to 1,25(OH)2D3 action in different types of cancer had been reported, none explained the loss of VDR expression. We have found that the transcription factors Snail1 and Snail2, known as inducers of epithelial-to-mesenchymal transition (EMT), inhibit VDR expression and block 1,25(OH)2D3 action in colon cancer cells. Snail1 and Snail2 have an additive repressing effect on VDR gene promoter. These effects are specific to the Snail family, as other transcription factors that function as EMT inducers do not inhibit VDR expression in colon cancer cells. Moreover, we also found that the RNA expression of SNAI1 and SNAI2 is upregulated in human colorectal tumors and inversely correlates with that of VDR. Our results suggest that high levels of SNAIL1 and SNAIL2 are a probable cause of VDR downregulation and 1,25(OH)2D3 unresponsiveness in colon cancer. In addition, they may contribute to the improvement of protocols for the clinical use of vitamin D compounds, as they indicate that advanced colon cancer patients overexpressing SNAIL1 and SNAIL2 are not suitable candidates for this therapy. © 2010 Elsevier Ltd.The work in authors’ laboratories is supported by the Ministerio de Ciencia e Innovación of Spain (SAF2007-60341, ISCIII-RETIC RD06/0020/0009 and RD06/0020/0020), Comunidad de Madrid (S-GEN-0266/2006) and European Union (MRTN-CT-2005-019496, NucSys).Peer Reviewe

Wnt and vitamin D at the crossroads in solid cancer

The Wnt/β-catenin signaling pathway is aberrantly activated in most colorectal cancers and less frequently in a variety of other solid neoplasias. Many epidemiological and experimental studies and some clinical trials suggest an anticancer action of vitamin D, mainly against colorectal cancer. The aim of this review was to analyze the literature supporting the interference of Wnt/β-catenin signaling by the active vitamin D metabolite 1α,25-dihydroxyvitamin D3. We discuss the molecular mechanisms of this antagonism in colorectal cancer and other cancer types. Additionally, we summarize the available data indicating a reciprocal inhibition of vitamin D action by the activated Wnt/β-catenin pathway. Thus, a complex mutual antagonism between Wnt/β-catenin signaling and the vitamin D system seems to be at the root of many solid cancers. Abnormal activation of the Wnt/β-catenin pathway is common in many types of solid cancers. Likewise, a large proportion of cancer patients have vitamin D deficiency. In line with these observations, Wnt/β-catenin signaling and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), the active vitamin D metabolite, usually have opposite effects on cancer cell proliferation and phenotype. In recent years, an increasing number of studies performed in a variety of cancer types have revealed a complex crosstalk between Wnt/β-catenin signaling and 1,25(OH)2D3. Here we review the mechanisms by which 1,25(OH)2D3 inhibits Wnt/β-catenin signaling and, conversely, how the activated Wnt/β-catenin pathway may abrogate vitamin D action. The available data suggest that interaction between Wnt/β-catenin signaling and the vitamin D system is at the crossroads in solid cancers and may have therapeutic applications.The work in the authors’ laboratory is funded by the Agencia Estatal de Investigación (PID2019-104867RB-I00/AEI/10.13039/501100011033), the Agencia Estatal de Investigación—Fondo Europeo de Desarrollo Regional (SAF2016-76377-R, MINECO/AEI/FEDER, EU), the Ministerio de Economía y Competitividad (SAF2017-90604-REDT/NuRCaMeIn), and the Instituto de Salud Carlos III—Fondo Europeo de Desarrollo Regional (CIBERONC; CB16/12/00273

Vitamin D and the Epithelial to Mesenchymal Transition

Altres ajuts: Comunidad de Madrid to Alberto Muñoz and Antonio García de Herreros (S2010/BMD-2344 Colomics2).Several studies support reciprocal regulation between the active vitamin D derivative 1 α,25-dihydroxyvitamin D (1,25(OH)D) and the epithelial to mesenchymal transition (EMT). Thus, 1,25(OH)D inhibits EMT via the induction of a variety of target genes that encode cell adhesion and polarity proteins responsible for the epithelial phenotype and through the repression of key EMT inducers. Both direct and indirect regulatory mechanisms mediate these effects. Conversely, certain master EMT inducers inhibit 1,25(OH)D action by repressing the transcription of VDR gene encoding the high affinity vitamin D receptor that mediates 1,25(OH)D effects. Consequently, the balance between the strength of 1,25(OH)D signaling and the induction of EMT defines the cellular phenotype in each context. Here we review the current understanding of the genes and mechanisms involved in the interplay between 1,25(OH)D and EMT

Organoids and colorectal cancer

Organoids were first established as a three‐dimensional cell culture system from mouse small intestine. Subsequent development has made organoids a key system to study many human physiological and pathological processes that affect a variety of tissues and organs. In particular, organoids are becoming very useful tools to dissect colorectal cancer (CRC) by allowing the circumvention of classical problems and limitations, such as the impossibility of long‐term culture of normal intestinal epithelial cells and the lack of good animal models for CRC. In this review, we describe the features and current knowledge of intestinal organoids and how they are largely contributing to our better understanding of intestinal cell biology and CRC genetics. Moreover, recent data show that organoids are appropriate systems for antitumoral drug testing and for the personalized treatment of CRC patients.The work in the authors’ laboratory is funded by the Agencia Estatal de Investigación (PID2019‐104867RB‐I00/AEI/10.13039/501100011033), the Ministerio de Ciencia e Innovación (SAF2017‐90604‐REDT/NuRCaMeIn), and the Instituto de Salud Carlos III—Fondo Europeo de Desarrollo Regional (CIBERONC/CB16/12/00273, CIBERONC/CB16/12/00398 and ICI20/00057)

Vitamin D Receptor Deficiency Enhances Wnt/β-Catenin Signaling and Tumor Burden in Colon Cancer

Aberrant activation of the Wnt/β-catenin pathway is critical for the initiation and progression of most colon cancers. This activation provokes the accumulation of nuclear β-catenin and the induction of its target genes. Apcmin/+ mice are the most commonly used model for colon cancer. They harbor a mutated Apc allele and develop intestinal adenomas and carcinomas during the first months of life. This phenotype is caused by the mutation of the second Apc allele and the consequent accumulation of nuclear β-catenin in the affected cells. Here we describe that vitamin D receptor (VDR) is a crucial modulator of nuclear β-catenin levels in colon cancer in vivo. By appropriate breeding of Apcmin/+ mice and Vdr+/− mice we have generated animals expressing a mutated Apc allele and two, one, or none Vdr wild type alleles. Lack of Vdr increased the number of colonic Aberrant Crypt Foci (ACF) but not that of adenomas or carcinomas in either small intestine or colon. Importantly, colon ACF and tumors of Apcmin/+Vdr-/- mice had increased nuclear β-catenin and the tumors reached a larger size than those of Apcmin/+Vdr+/+. Both ACF and carcinomas in Apcmin/+Vdr-/- mice showed higher expression of β-catenin/TCF target genes. In line with this, VDR knock-down in cultured human colon cancer cells enhanced β-catenin nuclear content and target gene expression. Consistently, VDR depletion abrogated the capacity of 1,25(OH)2D3 to promote the relocation of β-catenin from the nucleus to the plasma membrane and to inhibit β-catenin/TCF target genes. In conclusion, VDR controls the level of nuclear β-catenin in colon cancer cells and can therefore attenuate the impact of oncogenic mutations that activate the Wnt/β-catenin pathway

Vitamin D and Wnt3A have additive and partially overlapping modulatory effects on gene expression and phenotype in human colon fibroblasts

The Wnt/β-catenin signalling pathway is essential for intestinal epithelium homeostasis, but its aberrant activation is a hallmark of colorectal cancer (CRC). Several studies indicate that the bioactive vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) inhibits proliferation and promotes epithelial differentiation of colon carcinoma cells in part through antagonism of the Wnt/β-catenin pathway. It is now accepted that stromal fibroblasts are crucial in healthy and pathologic intestine: pericryptal myofibroblasts are constituents of the stem cell niche and cancer-associated fibroblasts (CAFs) contribute to CRC progression. However, studies on the combined action of 1,25(OH)2D3 and Wnt factors in colon fibroblasts are lacking. Here we show by global transcriptomic studies that 1,25(OH)2D3 and Wnt3A have profound, additive, partially overlapping effects on the gene expression profile of CCD-18Co human colon myofibroblasts. Moreover, 1,25(OH)2D3 and Wnt3A inhibit CCD-18Co cell proliferation and migration, while 1,25(OH)2D3 reduces, but Wnt3A increases, their capacity to contract collagen gels (a marker of fibroblast activation). These data were largely confirmed in patient-derived primary colon normal fibroblasts and CAFs, and in fibroblasts from other origins. Our results indicate that 1,25(OH)2D3 and Wnt3A are strong regulators of colon fibroblast biology and contribute to a better knowledge of intestinal homeostasis and stromal fibroblast action in CRCThe work in the authors’ laboratories is supported by the Spanish Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (FEDER) (SAF2016-76377-R, SAF2017-90604-REDT), Consejo Superior de Investigaciones Científicas (201820I058), and Instituto de Salud Carlos III - FEDER (CIBERONC, CB16/12/00273; CIBERES, CB15/00037

Exosomes enriched in stemness/metastatic-related mRNAS promote oncogenic potential in breast cancer

Cancer cells efficiently transfer exosome contents (essentially mRNAs and microRNAs) to other cell types, modifying immune responses, cell growth, angiogenesis and metastasis. Here we analyzed the exosomes release by breast tumor cells with different capacities of stemness/metastasis based on CXCR4 expression, and evaluated their capacity to generate oncogenic features in recipient cells. Breast cancer cells overexpressing CXCR4 showed an increase in stemness-related markers, and in proliferation, migration and invasion capacities. Furthermore, recipient cells treated with exosomes from CXCR4-cells showed increased in the same abilities. Moreover, inoculation of CXCR4-cell-derived exosomes in immunocompromised mice stimulated primary tumor growth and metastatic potential. Comparison of nucleic acids contained into exosomes isolated from patients revealed a >stemness and metastatic> signature in exosomes of patients with worse prognosis. Finally, our data supported the view that cancer cells with stem-like properties show concomitant metastatic behavior, and their exosomes stimulate tumor progression and metastasis. Exosomes-derived nucleic acids from plasma of breast cancer patients are suitable markers in the prognosis of such patients.Instituto de Salud Carlos III (ISCIII-AES2012: RTICC-RD12/0036/0041, RTICCRD12/0036/0021 and FIS: PI12/02037) from the National I+D+I 2013-2016 Plan and cofinanced by FEDER funds, SAF2010-20750, Fundación Banco Santander, Fundación Asociación Española Contra el Cáncer (AECC) and CM: S2010/BMD-2344.Peer Reviewe

Novel Snail1 Target Proteins in Human Colon Cancer Identified by Proteomic Analysis

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.[Background]: The transcription factor Snail1 induces epithelial-to-mesenchymal transition (EMT), a process responsible for the acquisition of invasiveness during tumorigenesis. Several transcriptomic studies have reported Snail1-regulated genes in different cell types, many of them involved in cell adhesion. However, only a few studies have used proteomics as a tool for the characterization of proteins mediating EMT. [Methodology/Principal Findings]: We identified by proteomic analysis using 2D-DIGE electrophoresis combined with MALDI-TOF-TOF and ESI-linear ion trap mass spectrometry a number of proteins with variable functions whose expression is modulated by Snail1 in SW480-ADH human colon cancer cells. Validation was performed by Western blot and immunofluorescence analyses. Snail1 repressed several members of the 14-3-3 family of phosphoserine/phosphothreonine binding proteins and also the expression of the Proliferation-associated protein 2G4 (PA2G4) that was mainly localized at the nuclear Cajal bodies. In contrast, the expression of two proteins involved in RNA processing, the Cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and the Splicing factor proline/glutamine-rich (SFPQ), was higher in Snail1-expressing cells than in controls. The regulation of 14-3-3 epsilon, 14-3-3 tau, 14-3-3 zeta and PA2G4 by Snail1 was reproduced in HT29 colon cancer cells. In addition, we found an inverse correlation between 14-3-3 sigma and Snail1 expression in human colorectal tumors. [Conclusions/Significance]: We have identified a set of novel Snail1 target proteins in colon cancer that expand the cellular processes affected by Snail1 and thus its relevance for cell function and phenotype.Peer reviewe

Vitamin D induces SIRT1 activation through K610 deacetylation in colon cancer

Posttranslational modifications of epigenetic modifiers provide a flexible and timely mechanism for rapid adaptations to the dynamic environment of cancer cells. SIRT1 is an NAD+-dependent epigenetic modifier whose activity is classically associated with healthy aging and longevity, but its function in cancer is not well understood. Here, we reveal that 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3, calcitriol), the active metabolite of vitamin D (VD), promotes SIRT1 activation through auto-deacetylation in human colon carcinoma cells, and identify lysine 610 as an essential driver of SIRT1 activity. Remarkably, our data show that the post-translational control of SIRT1 activity mediates the antiproliferative action of 1,25(OH)2D3. This effect is reproduced by the SIRT1 activator SRT1720, suggesting that SIRT1 activators may offer new therapeutic possibilities for colon cancer patients who are VD deficient or unresponsive. Moreover, this might be extrapolated to inflammation and other VD deficiency-associated and highly prevalent diseases in which SIRT1 plays a prominent role.Funding for this work was provided by the Agencia Estatal de Investigación (PID2019-104867RB-I00/AEI/10.13039/501100011033, RTI2018-099343-B-100 and PID2021-127645OA-I00); Instituto de Salud Carlos III (CIBERONC, CB16/12/00273 and CB16/12/00326); Comunidad de Madrid (Ayudas Atracción de Talento 2017-T1/BMD-5334 and 2021–5 A/BMD-20951; A385-DROPLET Young Reserchers R&D Project 2019 CAM-URJC; PRECICOLON-CM, P2022/BMD7212); Universidad Rey Juan Carlos (ADIPOMELM, Proyecto Puente de Investigación 2020)S