ERF deletion rescues RAS deficiency in mouse embryonic stem cells.

MEK inhibition in combination with a glycogen synthase kinase-3ß (GSK3ß) inhibitor, referred as the 2i condition, favors pluripotency in embryonic stem cells (ESCs). However, the mechanisms by which the 2i condition limits ESC differentiation and whether RAS proteins are involved in this phenomenon remain poorly understood. Here we show that RAS nullyzygosity reduces the growth of mouse ESCs (mESCs) and prohibits their differentiation. Upon RAS deficiency or MEK inhibition, ERF (E twenty-six 2 [Ets2]-repressive factor), a transcriptional repressor from the ETS domain family, translocates to the nucleus, where it binds to the enhancers of pluripotency factors and key RAS targets. Remarkably, deletion of Erf rescues the proliferative defects of RAS-devoid mESCs and restores their capacity to differentiate. Furthermore, we show that Erf loss enables the development of RAS nullyzygous teratomas. In summary, this work reveals an essential role for RAS proteins in pluripotency and identifies ERF as a key mediator of the response to RAS/MEK/ERK inhibition in mESCs.

Immuno-priming durvalumab with bevacizumab in HER2-negative advanced breast cancer: a pilot clinical trial.

BACKGROUND: Preclinical research suggests that the efficacy of immune checkpoint inhibitors in breast cancer can be enhanced by combining them with antiangiogenics, particularly in a sequential fashion. We sought to explore the efficacy and biomarkers of combining the anti-PD-L1 durvalumab plus the antiangiogenic bevacizumab after bevacizumab monotherapy for advanced HER2-negative breast cancer. METHODS: Patients had advanced HER2-negative disease that progressed while receiving single-agent bevacizumab maintenance as a part of a previous chemotherapy plus bevacizumab regimen. Treatment consisted of bi-weekly durvalumab plus bevacizumab (10 mg/kg each i.v.). Peripheral-blood mononuclear cells (PBMCs) were obtained before the first durvalumab dose and every 4 weeks and immunophenotyped by flow-cytometry. A fresh pre-durvalumab tumor biopsy was obtained; gene-expression studies and immunohistochemical staining to assess vascular normalization and characterize the immune infiltrate were conducted. Patients were classified as "non-progressors" if they had clinical benefit (SD/PR/CR) at 4 months. The co-primary endpoints were the changes in the percentage T cell subpopulations in PBMCs in progressors versus non-progressors, and PFS/OS time. RESULTS: Twenty-six patients were accrued. Median PFS and OS were 3.5 and 11 months; a trend for a longer OS was detected for the hormone-positive subset (19.8 versus 7.4 months in triple-negatives; P = 0.11). Clinical benefit rate at 2 and 4 months was 60% and 44%, respectively, without significant differences between hormone-positive and triple-negative (P = 0.73). Non-progressors' tumors displayed vascular normalization features as a result of previous bevacizumab, compared with generally abnormal patterns observed in progressors. Non-progressors also showed increased T-effector and T-memory signatures and decreased TREG signatures in gene expression studies in baseline-post-bevacizumab-tumors compared with progressors. Notably, analysis of PBMC populations before durvalumab treatment was concordant with the findings in tumor samples and showed a decreased percentage of circulating TREGs in non-progressors. CONCLUSIONS: This study reporting on sequential bevacizumab+durvalumab in breast cancer showed encouraging activity in a heavily pre-treated cohort. The correlative studies agree with the preclinical rationale supporting an immunopriming effect exerted by antiangiogenic treatment, probably by reducing TREGs cells both systemically and in tumor tissue. The magnitude of this benefit should be addressed in a randomized setting. TRIAL REGISTRATION: (www.clinicaltrials.gov): NCT02802098 . Registered on June 16, 2020.

Reprogramming in vivo produces teratomas and iPS cells with totipotency features.

Reprogramming of adult cells to generate induced pluripotent stem cells (iPS cells) has opened new therapeutic opportunities; however, little is known about the possibility of in vivo reprogramming within tissues. Here we show that transitory induction of the four factors Oct4, Sox2, Klf4 and c-Myc in mice results in teratomas emerging from multiple organs, implying that full reprogramming can occur in vivo. Analyses of the stomach, intestine, pancreas and kidney reveal groups of dedifferentiated cells that express the pluripotency marker NANOG, indicative of in situ reprogramming. By bone marrow transplantation, we demonstrate that haematopoietic cells can also be reprogrammed in vivo. Notably, reprogrammable mice present circulating iPS cells in the blood and, at the transcriptome level, these in vivo generated iPS cells are closer to embryonic stem cells (ES cells) than standard in vitro generated iPS cells. Moreover, in vivo iPS cells efficiently contribute to the trophectoderm lineage, suggesting that they achieve a more plastic or primitive state than ES cells. Finally, intraperitoneal injection of in vivo iPS cells generates embryo-like structures that express embryonic and extraembryonic markers. We conclude that reprogramming in vivo is feasible and confers totipotency features absent in standard iPS or ES cells. These discoveries could be relevant for future applications of reprogramming in regenerative medicine.

PLCG1 mutations in cutaneous T-cell lymphomas.

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of primary cutaneous T-cell lymphoproliferative processes, mainly composed of mycosis fungoides and Sézary syndrome, the aggressive forms of which lack an effective treatment. The molecular pathogenesis of CTCL is largely unknown, although neoplastic cells show increased signaling from T-cell receptors (TCRs). DNAs from 11 patients with CTCL, both normal and tumoral, were target-enriched and sequenced by massive parallel sequencing for a selection of 524 TCR-signaling-related genes. Identified variants were validated by capillary sequencing. Multiple mutations were found that affected several signaling pathways, such as TCRs, nuclear factor κB, or Janus kinase/signal transducer and activator of transcription, but PLCG1 was found to be mutated in 3 samples, 2 of which featured a redundant mutation (c.1034T>C, S345F) in exon 11 that affects the PLCx protein catalytic domain. This mutation was further analyzed by quantitative polymerase chain reaction genotyping in a new cohort of 42 patients with CTCL, where it was found in 19% of samples. Immunohistochemical analysis for nuclear factor of activated T cells (NFAT) showed that PLCG1-mutated cases exhibited strong NFAT nuclear immunostaining. Functional studies demonstrated that PLCG1 mutants elicited increased downstream signaling toward NFAT activation, and inhibition of this pathway resulted in reduced CTCL cell proliferation and cell viability. Thus, increased proliferative and survival mechanisms in CTCL may partially depend on the acquisition of somatic mutations in PLCG1 and other genes that are essential for normal T-cell differentiation.

MicroRNA-22 is induced by vitamin D and contributes to its antiproliferative, antimigratory and gene regulatory effects in colon cancer cells.

Vitamin D deficiency is associated with the high risk of colon cancer and a variety of other diseases. The active vitamin D metabolite 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) regulates gene transcription via its nuclear receptor (VDR), and posttranscriptional regulatory mechanisms of gene expression have also been proposed. We have identified microRNA-22 (miR-22) and several other miRNA species as 1,25(OH)(2)D(3) targets in human colon cancer cells. Remarkably, miR-22 is induced by 1,25(OH)(2)D(3) in a time-, dose- and VDR-dependent manner. In SW480-ADH and HCT116 cells, miR-22 loss-of-function by transfection of a miR-22 inhibitor suppresses the antiproliferative effect of 1,25(OH)(2)D(3). Additionally, miR-22 inhibition increases cell migration per se and decreases the antimigratory effect of 1,25(OH)(2)D(3) in both cell types. In silico analysis shows a significant overlap between genes suppressed by 1,25(OH)(2)D(3) and miR-22 putative target genes. Consistently, miR-22 inhibition abrogates the 1,25(OH)(2)D(3)-mediated suppression of NELL2, OGN, HNRPH1, RERE and NFAT5 genes. In 39 out of 50 (78%) human colon cancer patients, miR-22 expression was found lower in the tumour than in the matched normal tissue and correlated directly with that of VDR. Our results indicate that miR-22 is induced by 1,25(OH)(2)D(3) in human colon cancer cells and it may contribute to its antitumour action against this neoplasia.

Kras oncogene ablation prevents resistance in advanced lung adenocarcinomas.

KRASG12C inhibitors have revolutionized the clinical management of patients with KRASG12C-mutant lung adenocarcinoma. However, patient exposure to these inhibitors leads to the rapid onset of resistance. In this study, we have used genetically engineered mice to compare the therapeutic efficacy and the emergence of tumor resistance between genetic ablation of mutant Kras expression and pharmacological inhibition of oncogenic KRAS activity. Whereas Kras ablation induces massive tumor regression and prevents the appearance of resistant cells in vivo, treatment of KrasG12C/Trp53-driven lung adenocarcinomas with sotorasib, a selective KRASG12C inhibitor, caused a limited antitumor response similar to that observed in the clinic, including the rapid onset of resistance. Unlike in human tumors, we did not observe mutations in components of the RAS-signaling pathways. Instead, sotorasib-resistant tumors displayed amplification of the mutant Kras allele and activation of xenobiotic metabolism pathways, suggesting that reduction of the on-target activity of KRASG12C inhibitors is the main mechanism responsible for the onset of resistance. In sum, our results suggest that resistance to KRAS inhibitors could be prevented by achieving a more robust inhibition of KRAS signaling mimicking the results obtained upon Kras ablation.

Genomic and immune landscape Of metastatic pheochromocytoma and paraganglioma.

The mechanisms triggering metastasis in pheochromocytoma/paraganglioma are unknown, hindering therapeutic options for patients with metastatic tumors (mPPGL). Herein we show by genomic profiling of a large cohort of mPPGLs that high mutational load, microsatellite instability and somatic copy-number alteration burden are associated with ATRX/TERT alterations and are suitable prognostic markers. Transcriptomic analysis defines the signaling networks involved in the acquisition of metastatic competence and establishes a gene signature related to mPPGLs, highlighting CDK1 as an additional mPPGL marker. Immunogenomics accompanied by immunohistochemistry identifies a heterogeneous ecosystem at the tumor microenvironment level, linked to the genomic subtype and tumor behavior. Specifically, we define a general immunosuppressive microenvironment in mPPGLs, the exception being PD-L1 expressing MAML3-related tumors. Our study reveals canonical markers for risk of metastasis, and suggests the usefulness of including immune parameters in clinical management for PPGL prognostication and identification of patients who might benefit from immunotherapy.

Whole genome analysis of p38 SAPK-mediated gene expression upon stress.

BACKGROUND: Cells have the ability to respond and adapt to environmental changes through activation of stress-activated protein kinases (SAPKs). Although p38 SAPK signalling is known to participate in the regulation of gene expression little is known on the molecular mechanisms used by this SAPK to regulate stress-responsive genes and the overall set of genes regulated by p38 in response to different stimuli. RESULTS: Here, we report a whole genome expression analyses on mouse embryonic fibroblasts (MEFs) treated with three different p38 SAPK activating-stimuli, namely osmostress, the cytokine TNFalpha and the protein synthesis inhibitor anisomycin. We have found that the activation kinetics of p38alpha SAPK in response to these insults is different and also leads to a complex gene pattern response specific for a given stress with a restricted set of overlapping genes. In addition, we have analysed the contribution of p38alpha the major p38 family member present in MEFs, to the overall stress-induced transcriptional response by using both a chemical inhibitor (SB203580) and p38alpha deficient (p38alpha-/-) MEFs. We show here that p38 SAPK dependency ranged between 60% and 88% depending on the treatments and that there is a very good overlap between the inhibitor treatment and the ko cells. Furthermore, we have found that the dependency of SAPK varies depending on the time the cells are subjected to osmostress. CONCLUSIONS: Our genome-wide transcriptional analyses shows a selective response to specific stimuli and a restricted common response of up to 20% of the stress up-regulated early genes that involves an important set of transcription factors, which might be critical for either cell adaptation or preparation for continuous extra-cellular changes. Interestingly, up to 85% of the up-regulated genes are under the transcriptional control of p38 SAPK. Thus, activation of p38 SAPK is critical to elicit the early gene expression program required for cell adaptation to stress.

Comparative Study of Organoids from Patient-Derived Normal and Tumor Colon and Rectal Tissue.

Colon and rectal tumors, often referred to as colorectal cancer, show different gene expression patterns in studies that analyze whole tissue biopsies containing a mix of tumor and non-tumor cells. To better characterize colon and rectal tumors, we investigated the gene expression profile of organoids generated from endoscopic biopsies of rectal tumors and adjacent normal colon and rectum mucosa from therapy-naive rectal cancer patients. We also studied the effect of vitamin D on these organoid types. Gene profiling was performed by RNA-sequencing. Organoids from a normal colon and rectum had a shared gene expression profile that profoundly differed from that of rectal tumor organoids. We identified a group of genes of the biosynthetic machinery as rectal tumor organoid-specific, including those encoding the RNA polymerase II subunits POLR2H and POLR2J. The active vitamin D metabolite 1α,25-dihydroxyvitamin D3/calcitriol upregulated stemness-related genes (LGR5, LRIG1, SMOC2, and MSI1) in normal rectum organoids, while it downregulated differentiation marker genes (TFF2 and MUC2). Normal colon and rectum organoids share similar gene expression patterns and respond similarly to calcitriol. Rectal tumor organoids display distinct and heterogeneous gene expression profiles, with differences with respect to those of colon tumor organoids, and respond differently to calcitriol than normal rectum organoids.

Vitamin D differentially regulates colon stem cells in patient-derived normal and tumor organoids.

Intestine is a major target of vitamin D and several studies indicate an association between vitamin D deficiency and inflammatory bowel diseases (IBD), but also increased colorectal cancer (CRC) risk and mortality. However, the putative effects of 1α,25-dihydroxyvitamin D3 (calcitriol), the active vitamin D metabolite, on human colonic stem cells are unknown. Here we show by immunohistochemistry and RNAscope in situ hybridization that vitamin D receptor (VDR) is unexpectedly expressed in LGR5+ colon stem cells in human tissue and in normal and tumor organoid cultures generated from patient biopsies. Interestingly, normal and tumor organoids respond differentially to calcitriol with profound and contrasting changes in their transcriptomic profiles. In normal organoids, calcitriol upregulates stemness-related genes, such as LGR5, SMOC2, LRIG1, MSI1, PTK7, and MEX3A, and inhibits cell proliferation. In contrast, in tumor organoids calcitriol has little effect on stemness-related genes while it induces a differentiated phenotype, and variably reduces cell proliferation. Concordantly, electron microscopy showed that calcitriol does not affect the blastic undifferentiated cell phenotype in normal organoids but it induces a series of differentiated features in tumor organoids. Our results constitute the first demonstration of a regulatory role of vitamin D on human colon stem cells, indicating a homeostatic effect on colon epithelium with relevant implications in IBD and CRC.

Present status of Medical Physics practice in Mexico: An occupational analysis.

PURPOSE: To present an overview of the status of Medical Physics practice in Mexico, promote the legal recognition of Medical Physics high-end training, and provide information that will potentially improve the Mexican healthcare system. METHODS: For the purpose of this research, the concept of "Medical Physics Professional/s" (MPP) is introduced to refer to any person/s executing the role of a clinical medical physicist (cMP) in whole or in part independent of academic profile, training or experience. A database of MPP in Mexico was built from official sources and personal communication with peers. Database records included the following fields: employer/s, specialty, academic profile, and annual income (when available). RESULTS: 133 centers in Mexico employ MPP, 49% of which are public institutions. 360 positions involving cMP roles were identified at the National Healthcare System (occupied by 283 MPP), 77% of which corresponded to radiation therapy. Public healthcare services hold 65% of the reported positions. Only 40% of MPP hold a graduate degree in Medical Physics, 46% of whom were located in the most densely populated region of Mexico. Of all MPP, 32% were women. CONCLUSIONS: This work allowed to clearly identify the current challenges of Medical Physics practice in Mexico, such as: insufficiency and uneven geographical distribution of qualified manpower, gender imparity, multishifting and wage gap. The products derived from this work could be used to guide the efforts to improve the Mexican healthcare system.

Human immunodeficiency virus type 1 chronic infection is associated with different gene expression in MT-4, H9 and U937 cell lines.

To investigate cellular factors involved in HIV-1 chronic infection, three cell lines chronically infected with the same HIV-1 viral isolate (s61) were studied by cDNA microarray analysis. Two T cell lines, H61 and M61, showed the characteristics of a persistent infection whereas U61 cell line displayed a latent infection pattern. Analysis of genes with altered expression in the three cell lines revealed evidence of apoptosis control by up-regulation of anti-apoptotic genes and down-regulation of pro-apoptotic genes. In addition, cell cycle control was affected in the two persistent T cell lines particularly through the down-regulation of cyclin-dependent kinase inhibitor 1A (CDKN1A/p21). Moreover, each cell line showed specific characteristics, like in M61 cells, genes related with cellular activation and with cell migration and motility. In U61 cells, genes associated with immune response were activated. Genes with altered expression in our experiments, and not previously related with HIV such as ANXA 1 or CFLAR were detected and validated. This work revealed that different cell mechanism such as control of apoptosis and cell cycle are important for "in vitro" HIV-1 chronic infections, and discovered new genes previously not related with HIV-1 replication.

Urothelial organoids originating from Cd49fhigh mouse stem cells display Notch-dependent differentiation capacity.

Understanding urothelial stem cell biology and differentiation has been limited by the lack of methods for their unlimited propagation. Here, we establish mouse urothelial organoids that can be maintained uninterruptedly for >1 year. Organoid growth is dependent on EGF and Wnt activators. High CD49f/ITGA6 expression features a subpopulation of organoid-forming cells expressing basal markers. Upon differentiation, multilayered organoids undergo reduced proliferation, decreased cell layer number, urothelial program activation, and acquisition of barrier function. Pharmacological modulation of PPARγ and EGFR promotes differentiation. RNA sequencing highlighted genesets enriched in proliferative organoids (i.e. ribosome) and transcriptional networks involved in differentiation, including expression of Wnt ligands and Notch components. Single-cell RNA sequencing (scRNA-Seq) analysis of the organoids revealed five clusters with distinct gene expression profiles. Together, with the use of γ-secretase inhibitors and scRNA-Seq, confirms that Notch signaling is required for differentiation. Urothelial organoids provide a powerful tool to study cell regeneration and differentiation.

Exome Sequencing of Plasma DNA Portrays the Mutation Landscape of Colorectal Cancer and Discovers Mutated VEGFR2 Receptors as Modulators of Antiangiogenic Therapies.

Purpose: Despite the wide use of antiangiogenic drugs in the clinical setting, predictive biomarkers of response to these drugs are still unknown.Experimental Design: We applied whole-exome sequencing of matched germline and basal plasma cell-free DNA samples (WES-cfDNA) on a RAS/BRAF/PIK3CA wild-type metastatic colorectal cancer patient with primary resistance to standard treatment regimens, including inhibitors to the VEGF:VEGFR2 pathway. We performed extensive functional experiments, including ectopic expression of VEGFR2 mutants in different cell lines, kinase and drug sensitivity assays, and cell- and patient-derived xenografts.Results: WES-cfDNA yielded a 77% concordance rate with tumor exome sequencing and enabled the identification of the KDR/VEGFR2 L840F clonal, somatic mutation as the cause of therapy refractoriness in our patient. In addition, we found that 1% to 3% of samples from cancer sequencing projects harbor KDR somatic mutations located in protein residues frequently mutated in other cancer-relevant kinases, such as EGFR, ABL1, and ALK. Our in vitro and in vivo functional assays confirmed that L840F causes strong resistance to antiangiogenic drugs, whereas the KDR hot-spot mutant R1032Q confers sensitivity to strong VEGFR2 inhibitors. Moreover, we showed that the D717V, G800D, G800R, L840F, G843D, S925F, R1022Q, R1032Q, and S1100F VEGFR2 mutants promote tumor growth in mice.Conclusions: Our study supports WES-cfDNA as a powerful platform for portraying the somatic mutation landscape of cancer and discovery of new resistance mechanisms to cancer therapies. Importantly, we discovered that VEGFR2 is somatically mutated across tumor types and that VEGFR2 mutants can be oncogenic and control sensitivity/resistance to antiangiogenic drugs. Clin Cancer Res; 24(15); 3550-9. ©2018 AACR.

TrapSeq: An RNA Sequencing-Based Pipeline for the Identification of Gene-Trap Insertions in Mammalian Cells.

The development of haploid mammalian cell lines, coupled to next-generation sequencing, has recently facilitated forward genetic screenings in mammals. For mutagenesis, retrovirus- or transposon-based gene traps are frequently used. Current methods to map gene-trap insertions are based on inverse or splinkerette PCR, which despite their efficacy are prone to artifacts and do not provide information on expression of the targeted gene. Here, we describe a new RNA sequencing-based method (TrapSeq) to map gene-trap insertions. By recognizing chimeric mRNAs containing gene-trap sequences spliced to an exon, our method identifies insertions that lead to productive trapping. When applied to individual mutant clones, our method provides a fast and cost-effective way that not only identifies the insertion site but also reveals its impact on the expression of the trapped gene. As proof of principle, we conducted two independent screenings for resistance against 6-thioguanine and an ATR inhibitor, which identified mutations known to provide resistance to these reagents and revealed ECT2 as a novel determinant for the sensitivity to ATR inhibition.

Growth and molecular profile of lung cancer cells expressing ectopic LKB1: down-regulation of the phosphatidylinositol 3'-phosphate kinase/PTEN pathway.

Germ-line mutations in LKB1 gene cause the Peutz-Jeghers syndrome (PJS), a genetic disease with increased risk of malignancies. Recently, LKB1-inactivating mutations have been identified in one-third of sporadic lung adenocarcinomas, indicating that LKB1 gene inactivation is critical in tumors other than those of the PJS syndrome. However, the in vivo substrates of LKB1 and its role in cancer development have not been completely elucidated. Here we show that overexpression of wild-type LKB1 protein in A549 lung adenocarcinomas cells leads to cell-growth suppression. To examine changes in gene expression profiles subsequent to exogenous wild-type LKB1 in A549 cells, we used cDNA microarrays. We detected deregulation of 100 genes involved in cell proliferation, apoptosis, and cell adhesion. Strikingly, modification of the expression of well-known p53-responsive genes such as GADD45, TOP2A, and p21 suggests that growth suppression in A549 cells overexpressing LKB1 may be mediated by p53. In addition, PTEN up-regulation indicates that LKB1 could be involved in the PTEN/phosphatidylinositol-3'-kinase(PI3K)/AKT molecular pathway. Thus, our results give some insights into the understanding of how LKB1 inactivation contributes to lung carcinogenesis.

Differential gene expression profile in endometrioid and nonendometrioid endometrial carcinoma: STK15 is frequently overexpressed and amplified in nonendometrioid carcinomas.

Endometrial carcinoma (EC) comprises at least two types of cancer: endometrioid carcinomas (EECs) are estrogen-related tumors, which are frequently euploid and have a good prognosis. Nonendometrioid carcinomas (NEECs; serous and clear cell forms) are not estrogen related, are frequently aneuploid, and are clinically aggressive. We used cDNA microarrays containing 6386 different genes to analyze gene expression profiles in 24 EECs and 11 NEECs to identify differentially expressed genes that could help us to understand differences in the biology and clinical outcome between histotypes. After supervised analysis of the microarray data, there was at least a 2-fold difference in expression between EEC and NEEC in 66 genes. The 31 genes up-regulated in EECs included genes known to be hormonally regulated during the menstrual cycle and to be important in endometrial homeostasis, such as MGB2, LTF, END1, and MMP11, supporting the notion that EEC is a hormone-related neoplasm. Conversely, of the 35 genes overexpressed in NEECs, three genes, STK15, BUB1, and CCNB2, are involved in the regulation of the mitotic spindle checkpoint. Because STK15 amplification/overexpression is associated with aneuploidy and an aggressive phenotype in other human tumors, we used fluorescence in situ hybridization to investigate whether STK15 amplification occurred in ECs. We found that STK15 was amplified in 55.5% of NEECs but not in any EECs (P

Expression profiling of T-cell lymphomas differentiates peripheral and lymphoblastic lymphomas and defines survival related genes.

PURPOSE: T-Cell lymphomas constitute heterogeneous and aggressive tumors in which pathogenic alterations remain largely unknown. Expression profiling has demonstrated to be a useful tool for molecular classification of tumors. EXPERIMENTAL DESIGN: Using DNA microarrays (CNIO-OncoChip) containing 6386 cancer-related genes, we established the expression profiling of T-cell lymphomas and compared them to normal lymphocytes and lymph nodes. RESULTS: We found significant differences between the peripheral and lymphoblastic T-cell lymphomas, which include a deregulation of nuclear factor-kappaB signaling pathway. We also identify differentially expressed genes between peripheral T-cell lymphoma tumors and normal T lymphocytes or reactive lymph nodes, which could represent candidate tumor markers of these lymphomas. Additionally, a close relationship between genes associated to survival and those that differentiate among the stages of disease and responses to therapy was found. CONCLUSIONS: Our results reflect the value of gene expression profiling to gain insight about the molecular alterations involved in the pathogenesis of T-cell lymphomas.

Profiling of Sox4-dependent transcriptome in skin links tumour suppression and adult stem cell activation.

Adult stem cells (ASCs) reside in specific niches in a quiescent state in adult mammals. Upon specific cues they become activated and respond by self-renewing and differentiating into newly generated specialised cells that ensure appropriate tissue fitness. ASC quiescence also serves as a tumour suppression mechanism by hampering cellular transformation and expansion (White AC et al., 2014). Some genes restricted to early embryonic development and adult stem cell niches are often potent modulators of stem cell quiescence, and derailed expression of these is commonly associated to cancer (Vervoort SJ et al., 2013). Among them, it has been shown that recommissioned Sox4 expression facilitates proliferation, survival and migration of malignant cells. By generating a conditional Knockout mouse model in stratified epithelia (Sox4 (cKO) mice), we demonstrated a delayed plucking-induced Anagen in the absence of Sox4. Skin global transcriptome analysis revealed a prominent defect in the induction of transcriptional networks that control hair follicle stem cell (HFSC) activation such as those regulated by Wnt/Ctnnb1, Shh, Myc or Sox9, cell cycle and DNA damage response-associated pathways. Besides, Sox4 (cKO) mice are resistant to skin carcinogenesis, thus linking Sox4 to both normal and pathological HFSC activation (Foronda M et al., 2014). Here we provide additional details on the analysis of Sox4-regulated transcriptome in Telogen and Anagen skin. The raw and processed microarray data is deposited in GEO under GSE58155.

Deregulated expression of Cdc6 in the skin facilitates papilloma formation and affects the hair growth cycle.

Cdc6 encodes a key protein for DNA replication, responsible for the recruitment of the MCM helicase to replication origins during the G1 phase of the cell division cycle. The oncogenic potential of deregulated Cdc6 expression has been inferred from cellular studies, but no mouse models have been described to study its effects in mammalian tissues. Here we report the generation of K5-Cdc6, a transgenic mouse strain in which Cdc6 expression is deregulated in tissues with stratified epithelia. Higher levels of CDC6 protein enhanced the loading of MCM complexes to DNA in epidermal keratinocytes, without affecting their proliferation rate or inducing DNA damage. While Cdc6 overexpression did not promote skin tumors, it facilitated the formation of papillomas in cooperation with mutagenic agents such as DMBA. In addition, the elevated levels of CDC6 protein in the skin extended the resting stage of the hair growth cycle, leading to better fur preservation in older mice.