Inactivation of capicua in adult mice causes T-cell lymphoblastic lymphoma

CIC (also known as Capicua) is a transcriptional repressor negatively regulated by RAS/MAPK signaling. Whereas the functions of Cic have been well characterized in Drosophila, little is known about its role in mammals. CIC is inactivated in a variety of human tumors and has been implicated recently in the promotion of lung metastases. Here, we describe a mouse model in which we inactivated Cic by selectively disabling its DNA-binding activity, a mutation that causes derepression of its target genes. Germline Cic inactivation causes perinatal lethality due to lung differentiation defects. However, its systemic inactivation in adult mice induces T-cell acute lymphoblastic lymphoma (T-ALL), a tumor type known to carry CIC mutations, albeit with low incidence. Cic inactivation in mice induces T-ALL by a mechanism involving derepression of its well-known target, Etv4. Importantly, human T-ALL also relies on ETV4 expression for maintaining its oncogenic phenotype. Moreover, Cic inactivation renders T-ALL insensitive to MEK inhibitors in both mouse and human cell lines. Finally, we show that Ras-induced mouse T-ALL as well as human T-ALL carrying mutations in the RAS/MAPK pathway display a genetic signature indicative of Cic inactivation. These observations illustrate that CIC inactivation plays a key role in this human malignancyThis work was supported by grants from the Fundació La Marató de TV3 (20131730/1) to G.J. and M.B., and the European Research Council (ERC-AG/ 250297-RAS AHEAD), the EU-Framework Programme (HEALTH-F2-2010-259770/LUNGTARGET and HEALTH-2010- 260791/EUROCANPLATFORM), the Spanish Ministry of Economy and Competitiveness (SAF2014-59864-R), the Autonomous Community of Madrid (S2011/BDM-2470/ONCOCYCLE), and the Asociación Española contra el Cáncer (AECC) (GC16173694BARB) to M.B. M.B. is the recipient of an Endowed Chair from the AXA Research Fund. L.S.-C. was supported by a fellowship from the Programa de Formación de Personal Investigator (FPI) of the Spanish Ministry of Economy and Competitiveness.Peer reviewe

Overexpression of Periostin and Lumican in Esophageal Squamous Cell Carcinoma

To identify biomarkers for early detection for esophageal squamous cell carcinoma (ESCC), we previously carried out a genome-wide gene expression profiling study using an oligonucleotide microarray platform. This analysis led to identification of several transcripts that were significantly upregulated in ESCC compared to the adjacent normal epithelium. In the current study, we performed immunohistochemical analyses of protein products for two candidates genes identified from the DNA microarray analysis, periostin (POSTN) and lumican (LUM), using tissue microarrays. Increased expression of both periostin and lumican was observed in 100% of 137 different ESCC samples arrayed on tissue microarrays. Increased expression of periostin and lumican was observed in carcinoma as well as in stromal cell in the large majority of cases. These findings suggest that these candidates can be investigated in the sera of ESCC patients using ELISA or multiple reaction monitoring (MRM) type assays to further explore their utility as biomarkers

Complete Regression of Advanced Pancreatic Ductal Adenocarcinomas upon Combined Inhibition of EGFR and C-RAF

We thank B. Jime ́nez, M. San Roman, R. Villar, and S. Jime ́nez for excellenttechnical assistance; I. Arago ́n, A. Lo ́pez, F. Dı ́az,and I. Blanco (Animal Facil-ity) for mouse work; G. Visdomine, C. Pen ̃alba, and G. Garaulet (MolecularImaging Unit) for ultrasound studies; P. Vargiu (Transgenic Unit) for help ingenerating theTetO-FlpOstrain; N. Cabrera, A. de Martino (HistopathologyUnit) and M. Morente (Tumor Bank) for histopathological analysis, andC. Blanco and A. Cebria ́(Experimental Therapeutics) for determining theIC50values of gefinitib and erlotinib. Special thanks to J. de la Pen ̃a and E. Ortiz(Servicio de Anatomı ́aPatolo ́gica HCUVA) and T. Escamez and V. Navarro(Biobanco-IMIM) for their help with the PDX tumor models, and to R. Nieto,J.M. Ligo ́s, and M. Montoya (Cytometry Unit, CNIC) for fluorescence-activatedcell sorting analysis of apoptotic cells. This work was supported by grants fromthe European Research Council (advanced grants ERC-AG/250297-RASAHEAD and ERC-AG/695566-THERACAN), from the Spanish Ministry ofEconomy and Competitiveness (SAF2014-59864-R) to M.B. Additional sup-port was also obtained from grants from the Asociacio ́n Espan ̃ola contra elCa ́ncer (GC16173694BARB) to M.B. and B.S., from La Ligue Contre le Cancerto J.I., from the European Research Council (advanced grants ERC-2014-ADG) to M.H., and from the NIH (U54CA193313 and U54CA209997) to R.R.M.T.B was supported by an FPU fellowship from the Spanish Ministry of Edu-cation. C.N. was supported by a Juan de la Cierva Award. M. Djurec waspartially supported by a pre-doctoral fellowship from La Caixa. J.P.-P. wassupported by a Severo Ochoa FPI fellowship from the Spanish Ministry ofEconomy and Competitiveness. M.B. is the recipient of an Endowed Chairfrom the AXA Research Fund.Five-year survival for pancreatic ductal adenocarcinoma (PDAC) patients remains below 7% due to the lack of effective treatments. Here, we report that combined ablation of EGFR and c-RAF expression results in complete regression of a significant percentage of PDAC tumors driven by Kras/Trp53 mutations in genetically engineered mice. Moreover, systemic elimination of these targets induces toxicities that are well tolerated. Response to this targeted therapy correlates with transcriptional profiles that resemble those observed in human PDACs. Finally, inhibition of EGFR and c-RAF expression effectively blocked tumor progression in nine independent patient-derived xenografts carrying KRAS and TP53 mutations. These results open the door to the development of targeted therapies for PDAC patients.S

Hsp70 modulates immune response in pancreatic cancer through dendritic cells

Heat shock protein 70 (Hsp70), a protein chaperone, is known to promote cell survival and tumor progression. However, its role in the tumor microenvironment (TME) is largely unknown. We specifically evaluated Hsp70 in the TME by implanting tumors in wild-type (WT) controls or Hsp70 −/- animals, thus creating a TME with or without Hsp70. Loss of Hsp70 led to significantly smaller tumors; there were no differences in stromal markers, but interestingly, depletion of CD8 + T-cells abrogated this tumor suppressive effect, indicating that loss of Hsp70 in the TME affects tumor growth through the immune cells. Compared to WT, adoptive transfer of Hsp70 −/- splenocytes exhibited greater antitumor activity in immunodeficient NSG and Rag 1 −/- mice. Hsp70 −/- dendritic cells showed increased expression of MHCII and TNF-α both in vitro and in vivo. These results suggest that the absence of Hsp70 in the TME inhibits tumors through increased dendritic cell activation. Hsp70 inhibition in DCs may emerge as a novel therapeutic strategy against pancreatic cancer