PERSONNEL

PRINCIPAL INVESTIGATOR:

Víctor Javier Sánchez-Arévalo Lobo Ph.D. victor.sanchezarevalo@ufv.es

INVESTIGATORS:

Inmaculada Montanuy Sellat Ph.D.

EXTERNAL COLLABORATORS:

Bruno Amati Ph.D. (Instituto Europeo de Oncología, Milán, Italia)
Francisco X. Real Ph.D. (Centro Nacional de Investigaciones Oncológicas, Madrid)
Sandra Rodríguez Ph.D. (Centro Nacional de Investigaciones Oncológicas, Madrid)
Javier Hernández Losa Ph.D. (Hospital Vall d´hebron, Barcelona)
Santiago Ramón y Cajal Ph.D. (Hospital Vall d´hebron, Barcelona)
José Luis Rodríguez Peralto Ph.D. (Hospital 12 de Octubre, Madrid)
Yolanda Rodriguez Gil Ph.D. (Hospital 12 de Octubre, Madrid)

PREDOCTORAL INVESTIGATOR PT:

Raúl Muñoz Velasco
Ana García García
Irati Rekondo Izaguirre (Master Student)
Paula Jiménez Sánchez (Master Student)

LINE OF INVESTIGATION
Mechanisms of cellular plasticity and transformation associated with pancreatic cancer. Investigation of new therapeutic targets.

SUMMARY OF THE RESEARCH PROJECT

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a 5% survival rate. Its poor prognosis is due to a late diagnosis – once the tumour has already metastasised – and its resistance to chemotherapy. The only effective therapy at the moment is surgery, yet, this is only possible in 15-20% of cases. Therefore, finding new therapeutic strategies is a major clinical need.

The linear model that explains the origin and progression of PDAC is similar to the one described for colon, where a series of molecular alterations correlate with the degrees of dysplasia associated with precursor lesions (PanINs). PanIN-1a and 1b are characterized by the presence of elongated of ductal cells and mucus production (mucinous metaplasia), mild nuclear atypia and KRAS mutations; PanIN-1b add to the mucinous metaplasia the formation of papillae or micro papillae; it keeps the atypia slightly and molecularly show inactivation of CDKN2A. PanIN-2, show higher degree of dysplasia, stack nuclei that look hyperchromatic and lose polarity, and molecularly correlate with CDKN2A inactivation. The appearance of mitosis is usually limited to the basal layer (not apical). The presence of atypical mitosis or towards the luminal pole is related to greater dysplasia, molecularly they are characterized by the inactivation or loss of the SMAD4 gene. Finally, PanIN-3 is considered a carcinoma in situ, and is characterized by TP53 and BRCA2 losses. The overexpression of the c-MYC oncogene occurs in forty two percent of PDACs as a result of KRAS activation, copy number gain or gene amplifications {Ying:2012bv}. This linear model is currently under debate, Nota et al. suggest that genomic instability due to chromotripsis have an important role in PDAC genetics specifically at early stages {Notta:2016ky}.

Several research groups have demonstrated the relevance of differentiation as a protective mechanism against cellular transformation, and how dedifferentiated cells are more prone to transformation. Inflammatory responses, such as pancreatitis, can induce dedifferentiation of acinar cells and their posterior trans-differentiation to ductal cells through a process known as acinar-to-ductal metaplasia (ADM). This is a reversible process, although when it becomes chronic it can induce cellular transformation. Based on this hypothesis, our laboratory has demonstrated how c-MYC oncogene can induce a dedifferentiated state, supressing the acinar program and promoting cellular transformation.

We want to explore how c-MYC recognizes the different landscape -normal versus oncogenic- and executes specific genetic programs. To bind to the DNA and induce transcription of its target genes, c-MYC heterodimerizes with the ubiquitous transcription factor MAX to recognize specific sequences named E-box. There are more that 25,000 c-MYC binding sites in the genome and the differential recognition of those sites depends on the epigenetic context -defined by the combination of several histone marks- that constitute a prerequisite for c-MYC binding 12. The presence of CpG islands and activating marks (H3K4me3, H3K79me and H3ac) defines high affinity c-MYC binding sites, named “euchromatic island”, while low affinity sites show repressing marks (H4K16ac) 13. c-MYC requires specific chromatin remodelers to recognize those marks and bind chromatin. Sabo et al have described a model to explain the recognition of these binding sites: c-MYC scans the chromatin and through protein-protein interactions with chromatin remodelers it is stabilized to recognize DNA sequences and transcribe its target genes 14. Supporting this hypothesis, we have recently described a new c-MYC chromatin remodeler named BPTF (Bromodomain PHD finger transcription factor); BPTF is a member of the hNURF complex that recognizes H3K4me3 and H4K16ac and promotes nucleosome sliding and H1 exchange.

Our aim is to expand these results and explore the roles of c-MYC and BPTF during acinar transformation and dedifferentiation as well as their role as therapeutic targets in PADC models driven by KRAS. In addition to BPTF´s therapeutic potential, there are several work lines supporting the relevance of chromatin modifiers and remodelers as therapeutic targets. In order to address this challenge, we focus on the genetic search – “screening”- of new therapeutic targets through CRISPR/Cas9 sgRNA libraries in collaboration with Dr. Sandra Rodríguez, who leads the Cytogenetics unit at CNIO, with the objective of exploring possible synergies with current PDAC treatments.

PUBLICATIONS RELATED TO THE LINE OF RESEARCH

Cobo, I., Martinelli, P., Flandez, M., Bakiri, L., Zhang, M., Carrillo-de-Santa-Pau, E., Jia, Jinping., Sanchez-Arevalo Lobo, V. J., et al. (2018). Transcriptional regulation by NR5A2 links differentiation and inflammation in the pancreas. Nature, 554(7693), 533–537. http://doi.org/10.1038/nature25751.

Sanchez-Arevalo Lobo, V. J*., Fernández, L. C., Carrillo-de-Santa-Pau, E., Richart, L., Cobo, I., Cendrowski, J., et al. (2017). c-Myc downregulation is required for preacinar to acinar maturation and pancreatic homeostasis. Gut. http://doi.org/10.1136/gutjnl-2016-312306.

Richart, L., Real, F. X., & Sánchez-Arévalo Lobo, V. J*. (2016). c-MYC partners with BPTF in human cancer. Molecular & Cellular Oncology, 3(3), e1152346. http://doi.org/10.1080/23723556.2016.1152346.

Mazarico, J. M., Sanchez-Arevalo Lobo, V. J*., Favicchio, R., Greenhalf, W., Costello, E., Carrillo-de-Santa-Pau, E., et al. (2016). Choline Kinase Alpha (CHKα) as a Therapeutic Target in Pancreatic Ductal Adenocarcinoma: Expression, Predictive Value, and Sensitivity to Inhibitors. Molecular Cancer Therapeutics, 15(2), 323–333. http://doi.org/10.1158/1535-7163.MCT-15-0214.

Richart, L., Carrillo-de-Santa-Pau, E., Río-Machín, A., de Andrés, M. P., Cigudosa, J. C., Lobo, Sanchez-Arevalo Lobo, V. J*., & Real, F. X*. (2016). BPTF is required for c-MYC transcriptional activity and in vivo tumorigenesis. Nature Communications, 7, 10153. http://doi.org/10.1038/ncomms10153.

PROJECTS (last 5 years)

BPTF y remodeladores de cromatina como nuevas dianas terapéuticas en el carcinoma de páncreas. Fondo de Investigaciones Sanitarias (FIS). Investigador Principal. PI18/01080. Duración: Enero 2019-Diciembre 2022.

BPTF como diana terapéutica y regulador de la plasticidad celular en el adenocarcinoma pancreático ductal. ASEICA +QUEUNTRAIL. Investigador Principal. Duración Enero 2020-Diciembre 2020.

Red temática de investigación cooperativa en cáncer. Instituto de Salud Carlos III. Colaborador. RD12/0036/0034. Duración: 2013 – 2016 .

Development of BPTF-MYC functional inhibitors for anticancer therapy. ROCHE. Colaborador. Duración: 2013 – 2015
.

Control transcripcional de la diferenciación de las células acinares y cáncer de páncreas. MINECO. Colaborador. SAF2011-29530. Duración: 2012 – 2014
.

CANCERALIA-Development of novel diagnostic and therapeutic approaches to improve patients outcome in lung and pancreatic tumors. EU-FP7. Colaborador. 259737. Duración: 2011 – 2014.