The rates of adult neurogenesis and oligodendrogenesis are linked to cell cycle regulation through p27-dependent gene repression of SOX2

Cell differentiation involves profound changes in global gene expression that often has to occur in coordination with cell cycle exit. Because cyclin-dependent kinase inhibitor p27 reportedly regulates proliferation of neural progenitor cells in the subependymal neurogenic niche of the adult mouse brain, but can also have effects on gene expression, we decided to molecularly analyze its role in adult neurogenesis and oligodendrogenesis. At the cell level, we show that p27 restricts residual cyclin-dependent kinase activity after mitogen withdrawal to antagonize cycling, but it is not essential for cell cycle exit. By integrating genome-wide gene expression and chromatin accessibility data, we find that p27 is coincidentally necessary to repress many genes involved in the transit from multipotentiality to differentiation, including those coding for neural progenitor transcription factors SOX2, OLIG2 and ASCL1. Our data reveal both a direct association of p27 with regulatory sequences in the three genes and an additional hierarchical relationship where p27 repression of Sox2 leads to reduced levels of its downstream targets Olig2 and Ascl1. In vivo, p27 is also required for the regulation of the proper level of SOX2 necessary for neuroblasts and oligodendroglial progenitor cells to timely exit cell cycle in a lineage-dependent manne

SOX9 Triggers Different Epithelial to Mesenchymal Transition States to Promote Pancreatic Cancer Progression.

BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers mainly due to spatial obstacles to complete resection, early metastasis and therapy resistance. The molecular events accompanying PDAC progression remain poorly understood. SOX9 is required for maintaining the pancreatic ductal identity and it is involved in the initiation of pancreatic cancer. In addition, SOX9 is a transcription factor linked to stem cell activity and is commonly overexpressed in solid cancers. It cooperates with Snail/Slug to induce epithelial-mesenchymal transition (EMT) during neural development and in diseases such as organ fibrosis or different types of cancer. METHODS We investigated the roles of SOX9 in pancreatic tumor cell plasticity, metastatic dissemination and chemoresistance using pancreatic cancer cell lines as well as mouse embryo fibroblasts. In addition, we characterized the clinical relevance of SOX9 in pancreatic cancer using human biopsies. RESULTS Gain- and loss-of-function of SOX9 in PDAC cells revealed that high levels of SOX9 increased migration and invasion, and promoted EMT and metastatic dissemination, whilst SOX9 silencing resulted in metastasis inhibition, along with a phenotypic reversion to epithelial features and loss of stemness potential. In both contexts, EMT factors were not altered. Moreover, high levels of SOX9 promoted resistance to gemcitabine. In contrast, overexpression of SOX9 was sufficient to promote metastatic potential in K-Ras transformed MEFs, triggering EMT associated with Snail/Slug activity. In clinical samples, SOX9 expression was analyzed in 198 PDAC cases by immunohistochemistry and in 53 patient derived xenografts (PDXs). SOX9 was overexpressed in primary adenocarcinomas and particularly in metastases. Notably, SOX9 expression correlated with high vimentin and low E-cadherin expression. CONCLUSIONS Our results indicate that SOX9 facilitates PDAC progression and metastasis by triggering stemness and EMT

Loss of Caveolin-1 in Metastasis-Associated Macrophages Drives Lung Metastatic Growth through Increased Angiogenesis

Although it is well established that tumor-associated macrophages take part in each step of cancer progression, less is known about the distinct role of the so-called metastasis-associated macrophages (MAMs) at the metastatic site. Previous studies reported that Caveolin-1 (Cav1) has both tumor-promoting and tumor-suppressive functions. However, the role of Cav1 in bone-marrow-derived cells is unknown. Here, we describe Cav1 as an anti-metastatic regulator in mouse models of lung and breast cancer pulmonary metastasis. Among all the recruited inflammatory cell populations, we show that MAMs uniquely express abundant levels of Cav1. Using clodronate depletion of macrophages, we demonstrate that macrophage Cav1 signaling is critical for metastasis and not for primary tumor growth. In particular, Cav1 inhibition does not affect MAM recruitment to the metastatic site but, in turn, favors angiogenesis. We describe a mechanism by which Cav1 in MAMs specifically restrains vascular endothelial growth factor A/vascular endothelial growth factor receptor 1 (VEGF-A/VEGFR1) signaling and its downstream effectors, matrix metallopeptidase 9 (MMP9) and colony-stimulating factor 1 (CSF1).FWO-Strategic Basic Research (SB) doctoral fellowship (1S26917N), G.D.C. by a Pegasus FWO-Marie Curie fellowship (12114113N), A.I.O. by FCT Portugal (SFRH/BD/52287/2013), and M.E. by the DFG (EH 472/1-1) and Kom op tegen Kanker (Stand up to Cancer), the Flemish cancer society (2016/10538/2453). B.M.C. was funded by FCT Portugal (IF/00601/2012). M.M. received an ERC starting grant (OxyMO, 308459) and long-term structural Methusalem funding by the Flemish government (METH.14.08)info:eu-repo/semantics/publishedVersio

Metabolic rewiring induced by ranolazine improves melanoma responses to targeted therapy and immunotherapy

Resistance of melanoma to targeted therapy and immunotherapy is linked to metabolic rewiring. Here, we show that increased fatty acid oxidation (FAO) during prolonged BRAF inhibitor (BRAFi) treatment contributes to acquired therapy resistance in mice. Targeting FAO using the US Food and Drug Administration-approved and European Medicines Agency-approved anti-anginal drug ranolazine (RANO) delays tumour recurrence with acquired BRAFi resistance. Single-cell RNA-sequencing analysis reveals that RANO diminishes the abundance of the therapy-resistant NGFRhi neural crest stem cell subpopulation. Moreover, by rewiring the methionine salvage pathway, RANO enhances melanoma immunogenicity through increased antigen presentation and interferon signalling. Combination of RANO with anti-PD-L1 antibodies strongly improves survival by increasing antitumour immune responses. Altogether, we show that RANO increases the efficacy of targeted melanoma therapy through its effects on FAO and the methionine salvage pathway. Importantly, our study suggests that RANO could sensitize BRAFi-resistant tumours to immunotherapy. Since RANO has very mild side-effects, it might constitute a therapeutic option to improve the two main strategies currently used to treat metastatic melanoma

mTOR inhibition decreases SOX2-SOX9 mediated glioma stem cell activity and temozolomide resistance

<p><b>Background</b>: SOX2 and SOX9 are commonly overexpressed in glioblastoma, and regulate the activity of glioma stem cells (GSCs). Their specific and overlapping roles in GSCs and glioma treatment remain unclear.</p> <p><b>Methods</b>: <i>SOX2</i> and <i>SOX9</i> levels were examined in human biopsies. Gain and loss of function determined the impact of altering SOX2 and SOX9 on cell proliferation, senescence, stem cell activity, tumorigenesis and chemoresistance.</p> <p><b>Results</b>: SOX2 and SOX9 expression correlates positively in glioma cells and glioblastoma biopsies. High levels of SOX2 bypass cellular senescence and promote resistance to temozolomide. Mechanistic investigations revealed that SOX2 acts upstream of SOX9. mTOR genetic and pharmacologic (rapamycin) inhibition decreased SOX2 and SOX9 expression, and reversed chemoresistance.</p> <p><b>Conclusions</b>: Our findings reveal SOX2-SOX9 as an oncogenic axis that regulates stem cell properties and chemoresistance. We identify that rapamycin abrogate SOX protein expression and provide evidence that a combination of rapamycin and temozolomide inhibits tumor growth in cells with high SOX2/SOX9.</p

High expression of MKP1/DUSP1 counteracts glioma stem cell activity and mediates HDAC inhibitor response

Abstract The elucidation of mechanisms involved in resistance to therapies is essential to improve the survival of patients with malignant gliomas. A major feature possessed by glioma cells that may aid their ability to survive therapy and reconstitute tumors is the capacity for self-renewal. We show here that glioma stem cells (GSCs) express low levels of MKP1, a dual-specificity phosphatase, which acts as a negative inhibitor of JNK, ERK1/2, and p38 MAPK, while induction of high levels of MKP1 expression are associated with differentiation of GSC. Notably, we find that high levels of MKP1 correlate with a subset of glioblastoma patients with better prognosis and overall increased survival. Gain of expression studies demonstrated that elevated MKP1 impairs self-renewal and induces differentiation of GSCs while reducing tumorigenesis in vivo. Moreover, we identified that MKP1 is epigenetically regulated and that it mediates the anti-tumor activity of histone deacetylase inhibitors (HDACIs) alone or in combination with temozolomide. In summary, this study identifies MKP1 as a key modulator of the interplay between GSC self-renewal and differentiation and provides evidence that the activation of MKP1, through epigenetic regulation, might be a novel therapeutic strategy to overcome therapy resistance in glioblastoma

Papel de DUSP1 en progresión tumoral y en respuesta a CDDP en cáncer no microcítico de pulmón

DUSP1 es una fosfatasa que regula la actividad de las MAPK, JNK y p38, que además tiene un papel significativo en la biología tumoral y en la resistencia al cisplatino (CDDP). En este trabajo se estudia la función de DUSP1 en cáncer no microcítico de pulmón (CNMP). Para ello se realizó un análisis diferencial de la expresión génica global entre células de CNMP parentales (H460v) y células con expresión de DUSP1 inhibida (H460cri). En este estudio se observó que la inhibición en la expresión de DUSP1 induce cambios en las rutas biológicas involucradas en angiogénesis, actividad MAP quinasa, señalización célula-célula, la actividad del factores de crecimiento y receptores tirosina-quinasa. Estas diferencias observadas en expresión génica se complementaron con ensayos funcionales para estudiar la implicación de DUSP1 en angiogénesis y metástasis. Se observó que en células H460, la inhibición de la expresión DUSP1 disminuye la capacidad migratoria e invasiva, el crecimiento de tumores en ratones inmunodeprimidos y la metástasis inducida por estas células. También se observó que la inhibición de DUSP1 reduce el potencial angiogénico in vivo, dato que correlaciona con una disminución de la producción de VEGFC. A raíz de estos resultados, se realizó una aproximación translacional con muestras de biopsias de tumores de pacientes con CNMP, observándose una estrecha correlación entre la expresión de VEGFC y DUSP1 en las zonas de mayor vascularización. La expresión de DUSP1 parece estar relacionada con la resistencia encontrada frecuentemente en pacientes de CNMP al CDDP, quimioterápico de uso habitual en este tumor. Por tanto, se quiso profundizar en el conocimiento del papel de DUSP1 en respuesta al CDDP en células de CNMP. Para ello, se trataron las células H460v y H460cri con CDDP a diferentes tiempos y se estudiaron los cambios en la expresión génica mediante el uso de microarrays de expresión. Los resultados obtenidos indican que las células H460cri son más sensibles al CDDP, con un aumento en el porcentaje en células apoptóticas tras su tratamiento con este agente. En ambas líneas celulares la apoptosis está mediada por la actividad de p38, aunque en células H460v la activación de la apoptosis es vía p38-ATF2, mientras que en células H460cri parece ser independiente de ATF2 Como conclusión los resultados indican que DUSP1 juega un papel importante en la progresión tumoral en CNMP, probablemente debido a su participación en los procesos de angiogénesis y metástasis; además DUSP1 parece estar implicada en la aparición de resistencia al agente CDDP a través de una sutil regulación de los procesos apoptóticos mediados por la ruta p38.Peer reviewe

The dual-specificity protein phosphatase MkpB, homologous to mammalian MKP phosphatases, is required for D. discoideum post-aggregative development and cisplatin response

Dual-specificity protein phosphatases participate in signal transduction pathways inactivating mitogen-activated protein kinases (MAP kinases). These signaling pathways are of critical importance in the regulation of numerous biological processes, including cell proliferation, differentiation and development. The social ameba Dictyostelium discoideum harbors 14 genes coding for proteins containing regions very similar to the dual-specificity protein phosphatase domain. One of these genes, mkpB, additionally codes for a region similar to the Rhodanase domain, characteristic of animal MAP kinase-phosphatases, in its N-terminal region. Cells that over-express this gene show increased protein phosphatase activity. mkpB is expressed in D. discoideum ameba at growth but it is greatly induced at 12. h of multicellular development. Although it is expressed in all the cells of developmental structures, mkpB mRNA is enriched in cells with a distribution typical of anterior-like cells. Cells that express a catalytically inactive mutant of MkpB grow and aggregate like wild-type cells but show a greatly impaired post-aggregative development. In addition, the expression of cell-type specific genes is very delayed, indicating that this protein plays an important role in cell differentiation and development. Cells expressing the MkpB catalytically inactive mutant show increased sensitivity to cisplatin, while cells over-expressing wild type MkpB, or MkpA, proteins or mutated in the MAP kinase erkB gene are more resistant to this chemotherapeutic drug, as also shown in human tumor cells. © 2010 International Society of Differentiation.This work was supported by Grants BFU2008-02249 (LS) from the Dirección General de Investigación, Spanish Ministerio de Ciencia e Innovación, and PI08-1485 from the Fondo de Investigación Sanitaria (RP), respectively. VM-A is recipient of a FIS pre-doctoral fellowship and MG-C of a JAE pre-doctoral fellowship.Peer Reviewe

Cancer stem cells and cisplatin-resistant cells isolated from non-small-lung cancer cell lines constitute related cell populations

Lung cancer is the top cause of cancer-related deceases. One of the reasons is the development of resistance to the chemotherapy treatment. In particular, cancer stem cells (CSCs), can escape treatment and regenerate the bulk of the tumor. In this article, we describe a comparison between cancer cells resistant to cisplatin and CSCs, both derived from the non-small-cell lung cancer cell lines H460 and A549. Cisplatin-resistant cells were obtained after a single treatment with the drug. CSCs were isolated by culture in defined media, under nonadherent conditions. The isolated CSCs were clonogenic, could be differentiated into adherent cells and were less sensitive to cisplatin than the original cells. Cisplatin resistant and CSCs were able to generate primary tumors and to metastasize when injected into immunodeficient Nu/Nu mice, although they formed smaller tumors with a larger latency than untreated cells. Notably, under appropriated proportions, CSCs synergized with differentiated cells to form larger tumors. CSCs also showed increased capacity to induce angiogenesis in Nu/Nu mice. Conversely, H460 cisplatin-resistant cells showed increased tendency to develop bone metastasis. Gene expression analysis showed that several genes involved in tumor development and metastasis (EGR1, COX2, MALAT1, AKAP12, ADM) were similarly induced in CSC and cisplatin-resistant H460 cells, in agreement with a close similarity between these two cell populations. Cells with the characteristic growth properties of CSCs were also isolated from surgical samples of 18 out of 44 lung cancer patients. A significant correlation (P = 0.028) was found between the absence of CSCs and cisplatin sensitivity.B. D. López-Ayllon was supported by a Roche unrestricted grant. Supported by FIS PS09/00472, PI12/00386, PI11/00949; PI11/00537, and “Miguel Servet” financial support to Ibanez de Caceres, I (CP 08/000689; PI- 717).Peer Reviewe