Identificación de reguladores del factor derivado del epitelio pigmnetario en la progresión maligna del melanoma humano

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 26 de Julio de 201

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 effects on human colon normal and tumour organoids

Trabajo presentado en FEBS Open Bio, celebrado en Lisboa (Portugal) del 09 al 14 de julio de 2022.Many studies indicate an association between vitamin D deficiency and increased colorectal cancer risk and, specially, mortality. Accordingly, the active vitamin D metabolite 1a,25-dihydroxyvitamin D3 (calcitriol) inhibits the proliferation and promotes the differentiation of colon carcinoma cells and of other tumour cell types, and also has antitumour effects in animal models of colon cancer. These results prompted us to analyse the effects of calcitriol on human colon normal and cancer stem cells. To this end, we established a living biobank of patient-derived colon organoids generated from the tumour mass and from the adjacent healthy tissue obtained from surgical biopsies. Organoids are a three-dimensional culture system of normal or cancer stem cells and their progeny with a self-organized multicellular structure. By immunohistochemistry and RNAscope in situ hybridization, we found that vitamin D receptor is expressed in LGR5+ colon stem cells in human tissue and in normal and tumour organoid cultures. RNA-sequencing assays showed that both organoid types respond differentially to calcitriol with profound and contrasting changes in their transcriptomic profiles. This was confirmed in an independent series of patient-derived organoids by RT-qPCR assays. In normal organoids, calcitriol upregulates stemness-related genes and inhibits cell proliferation. In contrast, in tumour organoids calcitriol has little effect on stemnessrelated genes, while it induces differentiation-associated genes, and variably reduces cell proliferation. Concordantly, electron microscopy analyses showed that calcitriol does not affect the blastic cell phenotype in normal organoids, but it induces a series of differentiated features in tumour organoids. These results indicate that calcitriol maintains the undifferentiated phenotype of human normal colon stem cells (homeostatic action), while it promotes the differentiation of colon cancer stem cells (anticancer action).

Clinico-pathological characteristics and outcomes of patients with early-onset colorectal cancer

[Background]: The rising incidence of colorectal cancer (CRC) among young patients is alarming. We aim to characterize the clinico-pathological features and outcomes of patients with early-onset CRC (EOCRC). [Methods]: We included all of the patients with pathologically confirmed diagnosis of CRC at Hospital Universitario La Paz from October 2016 to September 2020. EOCRC age cut-off was 50 years. All statistical analyses were carried out using SPSS v.25. [Results]: A total of 1152 patients were diagnosed with CRC, fifty-nine (5,1%) of them were After a median follow-up of 24 months, 279 patients have died. Median overall survival (OS) was not reached in either group (p = 0,06). Three-year OS was 80% (95%CI: 73-87) and 67 (95%CI: 65-69) in the younger and older group, respectively. In patients with localized disease that underwent surgery or other antineoplastic treatment ( n = 856), 159 events for disease-free survival (DFS) were observed. Median DFS was [Conclusions]: Patients with EOCRC are diagnosed at a more advanced stage and display distinct biological features (more prevalence of dMMR and WT tumors among others). Studies focusing on screening in this population and deeper molecular profiling are needed

Clinico-pathological characteristics and outcomes of patients with early-onset colorectal cancer

[Background]: The rising incidence of colorectal cancer (CRC) among young patients is alarming. We aim to characterize the clinico-pathological features and outcomes of patients with early-onset CRC (EOCRC).[Methods]: We included all of the patients with pathologically confirmed diagnosis of CRC at Hospital Universitario La Paz from October 2016 to September 2020. EOCRC age cut-off was 50 years. All statistical analyses were carried out using SPSS v.25. [Results]: A total of 1152 patients were diagnosed with CRC, fifty-nine (5,1%) of them were After a median follow-up of 24 months, 279 patients have died. Median overall survival (OS) was not reached in either group (p ¼ 0,06). Three-year OS was 80% (95% CI: 73-87) and 67 (95%CI: 65-69) in the younger and older group, respectively. In patients with localized disease that underwent surgery or other antineoplastic treatment ( n ¼ 856), 159 events for disease-free survival (DFS) were observed. Median DFS was not reached in either group (p ¼0,144). Three-year DFS was 86% (95%CI: 79-93) and 73% (95%CI: 71-75, respectively). In patients with metastatic disease (n ¼ 332; synchronous or metachronic), median OS was not reach in the EOCRC group vs 18,1 (95%CI: 13,8-22,4), p ¼ 0,05). In those patients with metastatic EOCRC with mutational status assessed (n ¼23), no difference in OS according to RAS was observed (p ¼ 0,55).[Conclusions]: Patients with EOCRC are diagnosed at a more advanced stage and display distinct biological features (more prevalence of dMMR and WT tumors among others). Studies focusing on screening in this population and deeper molecular profiling are needed.Peer reviewe

Hypoxia Negatively Regulates Antimetastatic PEDF in Melanoma Cells by a Hypoxia Inducible Factor-Independent, Autophagy Dependent Mechanism

Pigment epithelium-derived factor (PEDF), a member of the serine protease inhibitor (SERPIN) superfamily, displays a potent antiangiogenic and antimetastatic activity in a broad range of tumor types. Melanocytes and low aggressive melanoma cells secrete high levels of PEDF, while its expression is lost in highly aggressive melanomas. PEDF efficiently abrogates a number of functional properties critical for the acquisition of metastatic ability by melanoma cells, such as neovascularization, proliferation, migration, invasiveness and extravasation. In this study, we identify hypoxia as a relevant negative regulator of PEDF in melanocytes and low aggressive melanoma cells. PEDF was regulated at the protein level. Importantly, although downregulation of PEDF was induced by inhibition of 2-oxoglutarate-dependent dioxygenases, it was independent of the hypoxia inducible factor (HIF), a key mediator of the adaptation to hypoxia. Decreased PEDF protein was not mediated by inhibition of translation through untranslated regions (UTRs) in melanoma cells. Degradation by metalloproteinases, implicated on PEDF degradation in retinal pigment epithelial cells, or by the proteasome, was also excluded as regulatory mechanism in melanoma cells. Instead, we found that degradation by autophagy was critical for PEDF downregulation under hypoxia in human melanoma cells. Our findings show that hypoxic conditions encountered during primary melanoma growth downregulate antiangiogenic and antimetastasic PEDF by a posttranslational mechanism involving degradation by autophagy and could therefore contribute to the acquisition of highly metastatic potential characteristic of aggressive melanoma cells

Colon cancer: organoids, microenvironment and vitamin D

Trabajo presentado en la Reunión Anual del Programa de Mecanismos de Progresión Tumoral de CIBERONC, celebrada en modalidad virtual el 13 de julio de 2022

From molecular basis to clinical insights: a challenging future for the vitamin D endocrine system in colorectal cancer

Colorectal cancer (CRC) is one of the most life-threatening neoplasias in terms of incidence and mortality worldwide. Vitamin D deficiency has been associated with an increased risk of CRC. 1α,25-Dihydroxyvitamin D3 [1,25(OH)2D3], the most active vitamin D metabolite, is a pleiotropic hormone that, through its binding to a transcription factor of the nuclear receptor superfamily, is a major regulator of the human genome. 1,25(OH)2D3 acts on colon carcinoma and stromal cells and displays tumor protective actions. Here, we review the variety of molecular mechanisms underlying the effects of 1,25(OH)2D3 in CRC, which affect multiple processes that are dysregulated during tumor initiation and progression. Additionally, we discuss the epidemiological data that associate vitamin D deficiency and CRC, and the most relevant randomized controlled trials of vitamin D3 supplementation conducted in both healthy individuals and CRC patients.The work in the authors' laboratory is funded by the Agencia Estatal de Investigación (PID2019-104867RB-I00 and PID2022-136729OB-I00; MCIN/AEI/10.13039/501100011033), the Instituto de Salud Carlos III – Fondo Europeo de Desarrollo Regional (CIBERONC/CB16/12/00273 and ICI20/00057), and the Comunidad de Madrid (S2022/BMD-7212). AF-B, MJL, AB, and JMG-S belong to the Spanish National Research Council (CSIC)'s Cancer Hub.Peer reviewe