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En las organizaciones se presentan varias debilidades vulnerables en los sistemas de control interno y en la manera en que las empresas gestionan su liquidez, de modo, que el control interno debe garantizar la efectividad de los objetivos económicos empresariales. El objetivo de este trabajo es analizar el constructo teórico del control interno mediante el modelo COSO, a través de un análisis meta-analítico. Adicionalmente, se aplicó la técnica estadística de meta-análisis, con el fin de evaluar el nivel de significancia y su sesgo de error, por tal razón se direccionó bajo un diseño metodológico mixto. Los resultados revelaron que el factor ambiente de control, es descuidado por parte de las organizaciones debido al empirismo que maneja el directorio administrativo de las pequeñas y medianas empresas. Se concluye que el modelo COSO, si mantiene relación consistente con el control interno y la gestión de liquidez empresarial. Palabras Clave: control interno, liquidez, gestión empresarial. Referencias [1]A. I. Calderón Peña y K. J. Jáuregui Salcedo, «El control interno y su relación con el cumplimiento de las obligaciones tributarias en las empresas comerciales,Chaclacayo, 2015,» Revista de Investigación Universitaria, vol. 5, nº 1, pp. 32-27, 2016. [2]H. Almeida, M. Campello, I. Cunha y M. S. Weisbach, «Corporate Liquidity Management: A conceptual Framework and Survey» El Annual Review of FinancialEconomics, vol. 6, pp. 135-162, 2014. [3]R. M. Cedeño Zambrano y L. M. Morell González, La gestión de riesgos en Ecuador: una aproximaciónevolutiva desde el control interno,» Cofín Habana., vol.12, nº 2, pp. 306-318, 2018. [4]M. P. Suntasig Tigse, El control interno del proceso de concesión de créditos y cobranzasy su incidencia en la liquidez de la empresa cereales La Pradera de la parroquia Belisario Quevedo, en el primer trimestre del año 2014, Latacunga: Universidad Técnica de Cotopaxi, 2014. [5]L. Graham, Internal Control Audit and Compliance, Canadá: JohnWiley & Sons, Inc., Hoboken, New Jersey. Published, 2015. [6]S. Mantilla, Auditoría del control interno (3a. ed.), México: ECOE, 2013. [7]N. Viloria, «Factores que inciden en el sistema de control interno de una organización.,» Actualidad Contable Faces, vol. 8, nº 11, pp. 87-92, 2005. [8]M. Samuel, Internal Control- Integrated Framework.,México: ECOE, 2008. [9]R. Estupiñán Gaitán, Administración de riesgos E.R.M. y la auditoría interna, 2006. [10]G. Rivas Márquez, «Modelos contemporáneos de control interno. Fundamentos teóricos,» Observatorio Laboral Revista Venezolana, vol. 4, nº 8, pp. 115-136, 2011. [11]S. A. Mantilla B, Control Interno Informe COSO, 2017. [12]L. R. Sánchez Sánchez, «COSO ERM y la Gestión de Riesgos.,» QUIPUKAMAYOC Revista de la Facultad de Ciencias Contables, vol. 23, nº 44, pp. 43-50, 2015. [13]M. E. Vivanco Vergara, «Los manuales de procedimientos como herramientas de control interno de una organización,» vol. 9, pp. 313-318, 2017. [14]A. L. Quispe Otoma, M. P. Padilla Matínez y J. A. Telot, «Tecnologías de información y comunicación en la gestión empresarial de pymes comerciales,» vol. XXXVIII, nº 1, pp. 81-92, 2017. [15]I. Domínguez García, «Evolución de la teoría sobre el análisis y gestión de la liquidez empresarial,» vol. 9, nº 1, pp. 66-80, 2015. [16]L. Gitman y C. Zutter, Prinpios de administración financiera, México, 2012. [17]F. Madrigal, S. Ayala y L. Chávez, «Análisis e interpretaciónde estados financieros en condiciones de incertidumbre,» vol. 2, p. 380, 2015. [18]J. Sánchez, «Cómo realizar una revisión sistemática y un meta-análisis,» Aula abierta, vol. 38, nº 2, pp. 53-64, 2010. [19]D. Ojeda y J. Wurth, «Qué es un Meta análisis ?,»Revista Chilena de Anestesía, nº 43, pp. 343-350, 2014. [20]J. A. González, E. Cobo y M. Villaró, «Revisión sistemática y meta-análisis,» Bioestadistica para no estadísticos, pp. 1-42, 2014. [21]E. Osadchy y E. M. Akhmetshin, «Development of the financial control system in the company in crisis,» Mediterranean Journal of Social Sciences, vol. 6, nº552, pp. 390-398, 2015. [22]I. C. Asubadin Azubadin, Control interno del Proceso de compras y su incidencia en la liquidez de la empresa comercial Yucailla Cia. Ltda. Latacunga durante el año 2010”, Latacunga: Universidad Técnica de Ambato, 2011. [23]J. C. Viera Quishpe, Diseño de un sistema de control interno administrativo y contable para el laboratorio autoservicio diésel de la sierra, ubicado en la ciudad de Latacunga, Latacunga: Universidad Central del Ecuador, 2015. [24]M. Nava Rosillón, «Análisis financiero: una herramienta clave para una gestión financiera eficiente.,» Revista Venezolana de Gerencia, vol. 14, nº 48, pp. 606-628, 2009. [25]S. P. Guayaquil Villarroel, El control interno y la razonabilidad de la información financiera en el Centro Comercial Popular de la ciudad de Latacunga en los locales comerciales de calzado en el período Enero - Junio 2016, Latacunga: Universidad Técnica de Ambato, 2015. [26]A. Masli, G. E. Peters, V. J. Richardson y J. Sanchez, «Examining the potential benefits of internal control monitoring technology, » Accounting Review, vol.85, nº 3, pp. 1001-1034, 2010. [27]D. C. Chasi Toca, “Gestión de riesgos y su incidencia en el control interno en el departamento financiero de la florícola fegacón cía. Ltda. Parroquia Joseguango bajo, cantón Latacunga, provincia de Cotopaxi”, Latacunga: Universidad Técnica De Cotopaxi Facultad, 2017.

La industria textil en el Ecuador ha sido un sector de gran aporte económico a la industria nacional. El objetivo de la investigación es analizar los costos de importación de productos textiles y su incidencia en la utilidad empresarial. La metodología se basó en un estudio de caso con un enfoque cuantitativo y un alcance de investigación correlacional, como información primaria se tomó los balances generales y de resultado de la de la empresa Texpadilla Cia. Ltda. Los resultados revelan que existe una relación directa entre los incoterms, seguro y valor total de los productos; de forma que, el CIF (seguro y flete) o FOB (Libre a Bordo) mantienen un coeficiente de regresión de R2= 0,9618 y una significancia ANOVA menor a cero. Se concluye que, los costos de importación de bienes textiles si inciden en la utilidad empresarial, pues, las variables poseen un alto grado de explicación. Palabras Clave: costos de importación, industria textil, utilidad empresarial. Referencias [1]S. Amaluisa, «Bajo nivel de crecimiento de la industria textil ecuatoriana,» Boletín de Coyuntura, Ambato, 2019. [2]B. Pinta, Estructura productiva del sector manufacturero ecuatoriano, un análisis territorial en el período 2000-2012, quito: facultad latinoamericana de ciencias sociales, 2017. [3]J.Basantes, E. González y M. Bonilla, Caracterización de las peqeñas y medianas empresa en el sector de la economía ecuatoriana, Chimborazo: Universidad de Oriente, 2015. [4]D.Rodriguez, «Importación costos y valores.,» 11 6 2020. [En línea]. Disponible: https://www.e-comex.com/costos-de-una-importacion/. [5]Primicias, «Producción de textiles está estancada,» 2010. [6]CFN, «ficha sectorial hiladura, tejedura y acabados de productos textiles,» 02 2018. [En línea]. Disponible: https://www.cfn.fin.ec/wp-content/uploads/2018/04/Ficha-Sectorial-Hiladura-Tejedura-y-Acabados-de-Productos-Textiles.pdf. [7]C. Robles, Costos históricos, Estado de México: Red Tercer Milenio S.C, 2020. [8]J. Gavelán, Costos de importación, Mexico: researchgate, 2015. [9]J. Carrión, Naturaleza del costo de importación, Quito: Todo Comercio Exterior, 2019. [10]A. Romero, «Agencia de Aduanas - Alberto Romero Sánchez y Cia. Ltda.,» 21 06 2020. [En línea]. Disponible: https://www.agenciaromero.cl/es/noticias/detalle/identifique-los-valores-cif-y-fob-en-transacciones-comerciales-12. [11]A. Romero, «Agencia de Aduanas,» 31 08 20. [En línea]. Disponible: https://www.agenciaromero.cl/es/noticias/detalle/identifique-los-valores-cif-y-fob-en-transacciones-comerciales-12. [12]G. Villarroel, «Quees Economia,» 01 05 2020. [En línea]. Disponible: https://www.queeseconomia.site/utilidad/#:~:text=La%20utilidad%20es%20el%20inter%C3%A9s,puede%20sacar%20de%20un%20producto.&text=Nos%20encontramos%20con%20tres%20tipos,la%20neta%20y%20la%20operacional. [13]K. Silva, «kueski,» ¿Qué es la utilidad bruta y cómo se calcula?, 20 02 2020. [En línea]. Disponible: https://kueski.com/blog/finanzas-personales/dinero-economia/que-es-la-utilidad-bruta/. [14]P.Roldán, «Economipedia,» 19 02 2019. [En línea]. Disponible: https://economipedia.com/definiciones/utilidad-neta.html. [15]A. Broseta, «¿Qué es la utilidad bruta, neta y operacional?: Fórmulas,» Mexico, 2016. [16]ProEcuador, «proecuador.gob.ec,» 2020. [En línea]. Disponible: https://www.proecuador.gob.ec/category/sector/confeccion-y-textil/. [17]Revista Lideres, «Sector textil es el segundo de Ecuador que genera más empleo,» Lideres Produccion, 16 03 2017. [18]Asociación de Industriales Textiles de Ecuador (AITE)., «Informe Asociación de Industriales Textiles de Ecuador (AITE).,» 2017. [En línea]. Available: https://pe.fashionnetwork.com/news/Las-exportaciones-textiles-de-ecuador-crecen-en-un-5-8-,1042825.html. [19]T. Gonzalez, «Fashion Net Work,» 6 12 2018. [En línea]. Disponible: https://pe.fashionnetwork.com/news/Las-exportaciones-textiles-de-ecuador-crecen-en-un-5-8-,1042825.html. [20]Banco Central del Ecuador, «Exportaciones por bloques económicos (SIN OTROS USOS),» 19 10 2019. [En línea]. Disponible: https://www.aite.com.ec/estadisticas/2018/EXPORT%202018%20BLOQUES%20ECON.%20SIN%20OTROS%20USOS.pdf. [21]Asociación de Industrias Textiles del Ecuador, «Asociación de Industrias Textiles del Ecuador,» 5 10 2019. [En línea]. Disponible: https://www.aite.com.ec/estadisticas/2018/IMPORT%202018%20TIPO%20PRODUCTO.pdf. [22]Textiles y confecciones en Ecuador, «textiles y confecciones en Ecuador,» 12 3 2014. [En línea]. Disponible: https://www.legiscomex.com/BancoMedios/Documentos%20PDF/estudio-textil-confecciones-ecuador-listo.pdf. [23]V. Yuliana y M. Pastaz, Barreras arancelarias y no arancelarias a las importaciones de textiles en el Ecuador y su impacto en los niveles de rentabilidad en la industria nacional, GUAYAQUIL: Universidad Laica VICENTE ROCAFUERTE, 2017. [24]A. Peiro, «Economipedia,» 10 05 2020. [En línea]. Disponible: https://economipedia.com/definiciones/coeficiente-de-correlacion-lineal.html#:~:text=La%20correlaci%C3%B3n%2C%20tambi%C3%A9n%20conocida%20como,variaci%C3%B3n%20conjunta%20entre%20dos%20variables.

Endothelin‐1 is a mitogenic peptide that activates several proliferation, survival, and invasiveness pathways. The effects of endothelin‐1 rely on its activation by endothelin‐converting enzyme‐1 (ECE1), which is expressed as four isoforms with different cytoplasmic N termini. Recently, isoform ECE1c has been suggested to have a role in cancer aggressiveness. The N terminus of ECE1c is phosphorylated by protein kinase CK2 (also known as casein kinase 2), and this enhances its stability and promotes invasiveness in colorectal cancer cells. However, it is not known how phosphorylation improves stability and why this is correlated with increased aggressiveness. We hypothesized that CK2 phosphorylation protects ECE1c from N‐terminal ubiquitination and, consequently, from proteasomal degradation. Here, we show that lysine 6 is the bona fide residue involved in ubiquitination of ECE1c and its mutation to arginine (ECE1cK6R) significantly impairs proteasomal degradation, thereby augmenting ECE1c stability, even in the presence of the CK2 inhibitor silmitasertib. Furthermore, colorectal cancer cells overexpressing ECE1cK6R displayed enhanced cancer stem cell (CSC) traits, including increased stemness gene expression, chemoresistance, self‐renewal, and colony formation and spheroid formation in vitro, as well as enhanced tumor growth and metastasis in vivo. These findings suggest that CK2‐dependent phosphorylation enhances ECE1c stability, promoting an increase in CSC‐like traits. Therefore, phospho‐ECE1c may be a biomarker of poor prognosis and a potential therapeutic target for colorectal cancer., CK2 phosphorylates the N terminus of ECE1c, impairing its proteasome‐dependent degradation and promoting invasiveness in colorectal cancer cells. We show that lys‐6 is the ubiquitinated residue and its mutation to arginine confers super‐stability to ECE1c. Moreover, overexpressed ECE1cK6R mutant significantly promotes cancer stem cell‐like traits and hence higher aggressiveness. In conclusion, CK2 inhibition may have a promising therapeutic use in colorectal cancer.

Breast cancer (BC) is the most common cancer among women worldwide. BRCA1/2 are responsible for 16–20% of the risk for hereditary BC. Other susceptibility genes have been identified; Fanconi Anemia Complementation Group M (FANCM) being one of these. Two variants in FANCM, rs144567652 and rs147021911, are associated with BC risk. These variants have been described in Finland, Italy, France, Spain, Germany, Australia, the United States, Sweden, Finnish, and the Netherlands, but not in the South American populations. Our study evaluated the association of the SNPs rs144567652 and rs147021911 with BC risk in non-carriers of BRCA1/2 mutations from a South American population. The SNPs were genotyped in 492 BRCA1/2-negative BC cases and 673 controls. Our data do not support an association between FANCM rs147021911 and rs144567652 SNPs and BC risk. Nevertheless, two BC cases, one with a family history of BC and the other with sporadic early-onset BC, were C/T heterozygotes for rs144567652. In conclusion, this is the first study related contribution of FANCM mutations and BC risk in a South American population. Nevertheless, more studies are necessary to evaluate if rs144567652 could be responsible for familial BC in BRCA1/2-negatives and for early-onset non-familial BC in Chilean BC cases.

MicroRNA-423 (miR-423) is highly expressed in breast cancer (BC). Previously, our group showed that the SNP rs6505162:C>A located in the pre-miR-423 was significantly associated with increased familial BC risk in patients with a strong family history of BC. Therefore, in this study, we evaluated the functional role of rs6505162 in mammary tumorigenesis in vitro to corroborate the association of this SNP with BC risk. We found that rs6505162:C>A upregulated expression of both mature miR-423 sequences (3p and 5p). Moreover, pre-miR-423-A enhanced proliferation, and promoted cisplatin resistance in BC cell lines. We also showed that pre-miR-423-A expression decreased cisplatin-induced apoptosis, and increased BC cell migration and invasion. We propose that the rs6505162-A allele promotes miR-423 overexpression, and that the rs6505162-A allele induces BC cell proliferation, viability, chemoresistance, migration, and invasion, and decreases cell apoptosis as a consequence. We suggest that rs6505162:C>A is a functional SNP site with potential utility as a marker for early diagnosis, prognosis, and treatment efficacy monitoring in BRCA1/2-negative BC patients, as well as a possible therapeutic target.

Variants in genes encoding for microRNAs have been associated with their deregulation in breast cancer (BC). Sequencing of microRNAs deregulated in BC was performed using DNA from Chilean patients with a strong family history and negative for mutations in BRCA1/BRCA2. Seventeen variants were identified, three of which were selected for a case-control association study: rs376491654 (miR-335), rs755634302 (miR-497), and rs190708267 (miR-155). For rs190708267 C>T, the heterozygous T allele was detected in four BC cases and absent in controls, while homozygous TT cases were not detected. Variants were modelled in silico, cloned in a plasmid, expressed in BC cell lines, and functional in vitro assays were performed. Overexpression of the miR-155-T allele increased mature miR-155-5p levels in both BC cell lines, suggesting that its presence alters pre-miR-155 processing. Moreover, BC cells overexpressing the miR-155-T allele showed increased proliferation, migration, and resistance to cisplatin-induced death compared to miR-155-C overexpressing cells. Of note, the 3′UTR of APC, GSK3β, and PPP1CA genes, all into the canonical Wnt signaling pathway, were identified as direct targets. APC and GSK3β mRNA levels decreased while PP1 levels increased. These results suggest a pathogenic role of the variant rs190708267 (miR-155) in BRCA 1/2 negative BC, conferring susceptibility and promoting traits of aggressiveness.

Endothelin-1 (ET-1) is involved in the regulation of steroidogenesis. Additionally, patients with castration-resistant prostate cancer (PCa) have a higher ET-1 plasma concentration than those with localized PCa and healthy individuals. The aim of the present study was to evaluate the effect of ET-1 on steroidogenesis enzymes, androgen receptor (AR) and testosterone (T) production in PCa cells. The expression levels of endothelin receptors in prostate tissue from patients with localized PCa by immunohistochemistry, and those in LNCaP and PC3 cells were determined reverse transcription-quantitative PCR (RT-qPCR) and western blotting. Furthermore, the expression levels of ET-1 were determined in LNCaP and PC3 cells by RT-qPCR and western blotting. The ET-1 receptor activation was evaluated by intracellular calcium measurement, the expression levels of AR and enzymes participating in steroidogenesis [cytochrome P450 family 11 subfamily A member 1 (CyP11A1), cytochrome P450 family 17 subfamily A member 1, aldo-keto reductase family member C2 and 3β-hydroxysteroid dehydrogenase/isomerase 2 (3β HSD2)] were determined by western blotting and T concentration was determined by ELISA using PC3 cells. The present results revealed higher expression levels of endothelin A receptor (ETAR) in tissues obtained from samples of patients with PCa with a low Gleason Score. No changes were identified for endothelin B receptor (ETBR). PC3 cells expressed higher levels of ET-1 and ETAR, while LNCaP cells exhibited higher expression levels of ETBR. Blocking of ETAR and endothelin B receptor decreased the expression levels of CyP11A1 and 3β HSD2 enzymes and AR in PC3 cells, as well as T secretion. These findings suggested that ET-1 has a potential role in modulating the intratumoral steroidogenesis pathway and might have relevance as a possible therapeutic target.

Indexación: Scopus. Endothelin-converting enzyme-1 (ECE1) activates the endothelin-1 peptide, which upregulates pathways that are related to diverse hallmarks of cancer. ECE1 is expressed as four isoforms differing in their N-terminal domains. Protein kinase CK2 phosphorylates the N-terminus of isoform ECE1c, enhancing its stability and promoting invasiveness of colorectal cancer cells. However, the specific residues in ECE1c that are phosphorylated by CK2 and how this phosphorylation promotes invasiveness was unknown. Here we demonstrate that Ser-18 and Ser-20 are the bona fide residues phosphorylated by CK2 in ECE1c. Thus, biphospho-mimetic ECE1cDD and biphospho-resistant ECE1cAA mutants were constructed and stably expressed in different colorectal cancer cells through lentiviral transduction. Biphospho-mimetic ECE1cDD displayed the highest stability in cells, even in the presence of the specific CK2 inhibitor silmitasertib. Concordantly, ECE1cDD-expressing cells showed enhanced hallmarks of cancer, such as proliferation, migration, invasiveness, and self-renewal capacities. Conversely, cells expressing the less-stable biphospho-resistant ECE1cAA showed a reduction in these features, but also displayed an important sensitization to 5-fluorouracil, an antineoplastic agent traditionally used as therapy in colorectal cancer patients. Altogether, these findings suggest that phosphorylation of ECE1c at Ser-18 and Ser-20 by CK2 promotes aggressiveness in colorectal cancer cells. Therefore, phospho-ECE1c may constitute a novel biomarker of poor prognosis and CK2 inhibition may be envisioned as a potential therapy for colorectal cancer patients. © Copyright © 2020 Pérez-Moreno, Quezada-Meza, Chavez-Almarza, Niechi, Silva-Pavez, Trigo-Hidalgo, Aguayo, Jara, Cáceres-Verschae, Varas-Godoy, Díaz, García de Herreros, Burzio and Tapia. https://www.frontiersin.org/articles/10.3389/fonc.2020.01004/full

Ovarian cancer is the first cause of death for gynecological malignances in developed countries and around 80% correspond to Epithelial Ovarian Cancer (EOC). Overexpression of Nerve Growth Factor (NGF) and its high affinity receptor TRKA are involved in EOC progression, modulating several oncogenic processes such as angiogenesis by the increase of Vascular Endothelial Growth Factor (VEGF). FSH receptors (FSH-R) are present in EOC, but their changes and contribution during EOC progression are still not thoroughly known. The aims of this study were to evaluate the abundance of FSH receptors during EOC differentiation and to determine whether FSH modulates oncoproteins such as NGF and VEGF in ovarian cells. FSH-R expression in EOC tissues and cell lines (A2780, poorly differentiated EOC cells and HOSE, non-tumoral ovarian surface epithelial cells) were measured by RT-PCR and laser capture of epithelial cells from EOC samples by qPCR. FSH-R protein levels were evaluated by immunohisto/cytochemistry. Additionally, ovarian explants and ovarian cell lines were stimulated with FSH and/or FSH-R inhibitor to assess NGF and VEGF mRNA and protein levels. The results showed that FSH-R levels decreased during EOC progression, nevertheless these receptors are still present in poorly differentiated EOC. FSH increased NGF expression in ovarian cells, which was prevented using a FSH-R inhibitor. Similarly, in ovarian cancer explants, FSH increased NGF and VEGF mRNA, as well as NGF protein levels. These results suggest that FSH would display a key role not only in initial stages of EOC, but also in late stages of this disease, by modulation of NGF and VEGF levels in EOC cells.

Triple-negative breast cancer (TNBC) represents a challenge in the search for new therapeutic targets. TNBCs are aggressive and generate resistance to chemotherapy. Tumors of TNBC patients with poor prognosis present a high level of adenosine deaminase acting on RNA1 (ADAR1). We explore the connection of ADAR1 with the canonical Wnt signaling pathway and the effect of modulation of its expression in TNBC. Expression data from cell line sequencing (DepMap) and TCGA samples were downloaded and analyzed. We lentivirally generated an MDA-MB-231 breast cancer cell line that overexpress (OE) ADAR1p110 or an ADAR knockdown. Abundance of different proteins related to Wnt/β-catenin pathway and activity of nuclear β-catenin were analyzed by Western blot and luciferase TOP/FOP reporter assay, respectively. Cell invasion was analyzed by matrigel assay. In mice, we study the behavior of tumors generated from ADAR1p110 (OE) cells and tumor vascularization immunostaining were analyzed. ADAR1 connects to the canonical Wnt pathway in TNBC. ADAR1p110 overexpression decreased GSK-3β, while increasing active β-catenin. It also increased the activity of nuclear β-catenin and increased its target levels. ADAR1 knockdown has the opposite effect. MDA-MB-231 ADAR1 (OE) cells showed increased capacity of invasion. Subsequently, we observed that tumors derived from ADAR1p110 (OE) cells showed increased invasion towards the epithelium, and increased levels of Survivin and CD-31 expressed in vascular endothelial cells. These results indicate that ADAR1 overexpression alters the expression of some key components of the canonical Wnt pathway, favoring invasion and neovascularization, possibly through activation of the β-catenin, which suggests an unknown role of ADAR1p110 in aggressiveness of TNBC tumors.

Indexación: Scopus. Increased expression of the TRPM4 channel has been reported to be associated with the progression of prostate cancer. However, the molecular mechanism underlying its effect remains unknown. This work found that decreasing TRPM4 levels leads to the reduced proliferation of PC3 cells. This effect was associated with a decrease in total β-catenin protein levels and its nuclear localization, and a significant reduction in Tcf/Lef transcriptional activity. Moreover, TRPM4 silencing increases the Ser33/Ser37/Thr41 β-catenin phosphorylated population and reduces the phosphorylation of GSK-3β at Ser9, suggesting an increase in β-catenin degradation as the underlying mechanism. Conversely, TRPM4 overexpression in LNCaP cells increases the Ser9 inhibitory phosphorylation of GSK-3β and the total levels of β-catenin and its nonphosphorylated form. Finally, PC3 cells with reduced levels of TRPM4 showed a decrease in basal and stimulated phosphoactivation of Akt1, which is likely responsible for the decrease in GSK-3β activity in these cells. Our results also suggest that the effect of TRPM4 on Akt1 is probably mediated by an alteration in the calcium/calmodulin-EGFR axis, linking TRPM4 activity with the observed effects in β-catenin-related signaling pathways. These results suggest a role for TRPM4 channels in β-catenin oncogene signaling and underlying mechanisms, highlighting this ion channel as a new potential target for future therapies in prostate cancer. https://febs.onlinelibrary.wiley.com/doi/abs/10.1002/1878-0261.12100

The family of non-coding mitochondrial RNAs (ncmtRNA) is differentially expressed according to proliferative status. Normal proliferating cells express sense (SncmtRNA) and antisense ncmtRNAs (ASncmtRNAs), whereas tumor cells express SncmtRNA and downregulate ASncmtRNAs. Knockdown of ASncmtRNAs with oligonucleotides induces apoptotic cell death of tumor cells, leaving normal cells unaffected, suggesting a potential application for developing a novel cancer therapy. In this study, we knocked down the ASncmtRNAs in melanoma cell lines with a lentiviral-encoded shRNA approach. Transduction with lentiviral constructs targeted to the ASncmtRNAs induced apoptosis in murine B16F10 and human A375 melanoma cells in vitro and significantly retarded B16F10 primary tumor growth in vivo. Moreover, the treatment drastically reduced the number of lung metastatic foci in a tail vein injection assay, compared to controls. These results provide additional proof of concept to the knockdown of ncmtRNAs for cancer therapy and validate lentiviral-shRNA vectors for gene therapy.

Curcumin is a natural antioxidant polyphenol, which decreases epithelial‑mesenchymal transition (EMT) and cell migration in cervical cancer cells. However, the mechanism by which such a decrease occurs is unclear. It is well established that cervical cancer can be caused by high‑risk human papillomavirus (HPV), which overexpresses E6 and E7 oncoproteins. Recent findings have suggested that viral oncoproteins regulate the expression of Pirin, which is an oxidative stress sensor involved in EMT and cell migration. Molecular markers associated with EMT, pirin and HPV were evaluated using reverse transcription‑reverse quantitative PCR and western blotting. In addition, the migratory ability of cells was evaluated using a Transwell assay. In order to evaluate the role of Pirin in curcumin‑mediated inhibition of EMT, SiHa cervical carcinoma cells, which contain two integrated copies of HPV16, were exposed to curcumin. Cell migration, and the expression levels of EMT biomarkers and the pirin protein, which is a product of the PIR gene, were subsequently evaluated. The results demonstrated a significant decrease in EMT following exposure to 20 µM curcumin for 72 h. This finding was supported by a decrease in the protein expression levels of N‑cadherin, Vimentin and Slug. Furthermore, it was observed that PIR expression and Pirin protein levels were significantly decreased when SiHa cells were exposed to curcumin. Subsequently, to analyze the effects of Pirin on EMT, SiHa cells were transfected with a small interfering RNA (siRNA) to knockdown PIR. A significant increase in E‑cadherin mRNA expression and a decrease in N‑cadherin protein expression were observed. In addition, a similar decrease was observed when SiHa cells were exposed to both PIR siRNA and curcumin. Finally, a significant decrease in SiHa cell migration was observed in the presence of 20 µM curcumin compared with in the control group. These findings suggested that curcumin may decrease EMT, at least in part by a Pirin‑dependent mechanism. Therefore, Pirin protein may be an important pharmacological target for cervical cancer treatment.

The endothelin-1 (ET-1) axis contributes to the pathophysiology of several cancers by promoting tumor development and progression. This peptide is activated from its precursor, big ET-1, by endothelin-converting enzyme-1 (ECE-1). Active ET-1 binds to its cognate G-coupled receptor, ETAR, which transduces the signal to the inside of the cell. ET-1 has a short half-life of about 90 s, so its biological effects are completely dependent on its enzymatic activation by ECE-1. Expression of ECE-1 is elevated in several tumors and cancer cell lines. There are four ECE-1 isoforms —ECE-1a, -1b, -1c, and -1d— which vary in terms of their subcellular localization and, in some cases, their effects on cancer-related properties such as proliferation and invasiveness. In this article, we review findings on the role of ECE-1, particularly isoform ECE-1c, in oncogenesis and malignant progression. We also review evidence regarding ECE-1 expression in several types of tumors and cancer cell lines. Recent findings from our laboratory and others allow us to speculate on the mechanism by which ECE-1c promotes cancer aggressiveness. Finally, we evaluate potential post-translational modifications of ECE-1c, highlighting phosphorylation by several kinases, as well as evidence pointing to a putative, non-canonical, ET-1-independent mechanism for promoting invasiveness. Taken together, current evidence suggests that ECE-1c contributes to cancer aggressiveness and plays a putative role as a key regulator of cancer progression. Therefore, we propose that this protein is a promising target for prognostic and therapeutic purposes.

Protein kinase CK2 is a highly conserved and constitutively active Ser/Thr-kinase that phosphorylates a large number of substrates, resulting in increased cell proliferation and survival. A known target of CK2 is Akt, a player in the PI3K/Akt/mTORC1 signaling pathway, which is aberrantly activated in 32% of colorectal cancer (CRC) patients. On the other hand, mTORC1 plays an important role in the regulation of protein synthesis, cell growth, and autophagy. Some studies suggest that CK2 regulates mTORC1 in several cancers. The most recently developed CK2 inhibitor, silmitasertib (formerly CX-4945), has been tested in phase I/II trials for cholangiocarcinoma and multiple myeloma. This drug has been shown to induce autophagy and enhance apoptosis in pancreatic cancer cells and to promote apoptosis in non-small cell lung cancer cells. Nevertheless, it has not been tested in studies for CRC patients. We show in this work that inhibition of CK2 with silmitasertib decreases in vitro tumorigenesis of CRC cells in response to G2/M arrest, which correlates with mTORC1 inhibition and formation of large cytoplasmic vacuoles. Notably, molecular markers indicate that these vacuoles derive from massive macropinocytosis. Altogether, these findings suggest that an aberrantly elevated expression/activity of CK2 may play a key role in CRC, promoting cell viability and proliferation in untreated cells, however, its inhibition with silmitasertib promotes methuosis-like cell death associated to massive catastrophic vacuolization, accounting for decreased tumorigenicity at later times. These characteristics of silmitasertib support a potential therapeutic use in CRC patients and probably other CK2-dependent cancers. Fil: Silva Pavez, Eduardo. Universidad de Chile; Chile Fil: Villar, Paulina. Universidad de Chile; Chile Fil: Trigo, César. Universidad de Chile; Chile Fil: Caamaño, Esteban. Universidad de Chile; Chile Fil: Niechi, Ignacio. Universidad de Chile; Chile. Universidad Austral de Chile; Chile Fil: Pérez, Pablo. Universidad de Chile; Chile Fil: Muñoz, Juan Pablo. Universidad de Chile; Chile Fil: Aguayo, Francisco. Universidad de Chile; Chile Fil: Burzio, Verónica A.. Universidad Andrés Bello; Chile Fil: Varas Godoy, Manuel. Universidad de Los Andes; Chile Fil: Castro, Ariel F.. Universidad de Concepción; Chile Fil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina Fil: Tapia, Julio C.. Universidad de Chile; Chile

Oncogenic kinase Aurora A (AURKA) has been found to be overexpresed in several tumors including colorectal, breast and hematological cancers. Overexpression of AURKA induces centrosome amplification and aneuploidy and it is related with cancer progression and poor prognosis. Here we show that AURKA phosphorylates in vitro the transcripcional co-repressor Ski on aminoacids Ser326 and Ser383. Phosphorylations on these aminoacids decreased Ski protein half-life. Reduced levels of Ski resulted in centrosomes amplification and multipolar spindles formation, same as AURKA overexpressing cells. Importantly, overexpression of Ski wild type, but not S326D and S383D mutants inhibited centrosome amplification and cellular transformation induced by AURKA. Altogether, these results suggest that the Ski protein is a target in the transformation pathway mediated by the AURKA oncogene. This article is protected by copyright. All rights reserved

// Ignacio Niechi 1 , Eduardo Silva 1 , Pablo Cabello 1 , Hernan Huerta 1 , Valentina Carrasco 1 , Paulina Villar 1 , Luis Rodrigo Cataldo 1 , Katherine Marcelain 2 , Ricardo Armisen 2 , Manuel Varas-Godoy 3 , Cristina Fernandez 4 , Julio C. Tapia 1, 2 1 Cell Transformation Laboratory, Program of Cellular and Molecular Biology, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile 2 ICBM, Faculty of Medicine, University of Chile, Santiago, Chile 3 Fundacion Ciencia y Vida, Santiago, Chile 4 Department of Anatomopathology, HCUCH, Faculty of Medicine, University of Chile, Santiago, Chile Correspondence to: Julio C. Tapia, e-mail: jtapia@med.uchile.cl Keywords: CK2, ECE-1, endothelin, colon cancer, metastasis Received: February 08, 2015 Accepted: October 06, 2015 Published: October 16, 2015 ABSTRACT Endothelin-converting enzyme-1c (ECE-1c) is a membrane metalloprotease involved in endothelin-1 synthesis, which has been shown in vitro to have a role in breast, ovary and prostate cancer cell invasion. N-terminal end of ECE-1c displays three putative phosphorylation sites for the protein kinase CK2. We studied whether CK2 phosphorylates N-terminal end of ECE-1c as well as whether this has a role in migration and invasion of colon cancer cells. CK2 phosphorylated the N-terminal end of ECE-1c and this was precluded upon inhibition of CK2. Inhibition also led to diminished protein levels of both endogen ECE-1 or GFP-fused N-terminal end of ECE-1c in 293T embryonic and DLD-1 colon cancer cells, which highlighted the importance of this motif on UPS-dependent ECE-1c degradation. Full-length ECE-1c mutants designed either to mimic or abrogate CK2-phosphorylation displayed increased or decreased migration/invasion of colon cancer cells, respectively. Moreover, ECE-1c overexpression or its silencing with a siRNA led to increased or diminished cell migration/invasion, respectively. Altogether, these data show that CK2-increased ECE-1c protein stability is related to augmented migration and invasion of colon cancer cells, shedding light on a novel mechanism by which CK2 may promote malignant progression of this disease.

We previously found that the small GTPase Rheb regulates the cell-cycle inhibitor p27KIP1 (p27) in colon cancer cells by a mTORC1-independent mechanism. However, the biological function of the Rheb/p27 axis in cancer cells remains unknown. Here, we show that siRNA-mediated depletion of Rheb decreases survival of human colon cancer cells under serum deprivation. As autophagy can support cell survival, we analyzed the effect of Rheb on this process by detecting the modification of the autophagy marker protein LC3 by western blot and imunofluorescence. We found that Rheb promotes autophagy in several human cancer cell lines under serum deprivation. Accordingly, blocking autophagy inhibited the pro-survival effect of Rheb in colon cancer cells. We then analyzed whether p27 was involved in the biological effect of Rheb. Depletion of p27 inhibited colon cancer cell survival, and Rheb induction of autophagy. These results suggest that p27 has an essential role in the effect of Rheb in response to serum deprivation. In addition, we demonstrated that the role of p27 in autophagy stands on the N-terminal portion of the protein, where the CDK-inhibitory domain is located. Our results indicate that a Rheb/p27 axis accounts for the activation of autophagy that supports cancer cell survival. Our work therefore highlights a biological function of Rheb and prompts the need for future studies to address whether the mTORC1-independent Rheb/p27 axis could contribute to tumorigenesis and/or resistance to mTOR inhibitors.

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Metastasis and poor responsiveness to chemotherapy in osteosarcoma correlates with over-expression of the runt-related transcription factor RUNX2, which normally plays a key role in osteogenic lineage commitment, osteoblast differentiation, and bone formation. Furthermore, WNT/β-catenin signaling is over-activated in osteosarcoma and promotes tumor progression. Importantly, the WNT/β-catenin pathway normally activates RUNX2 gene expression during osteogenic lineage commitment. Therefore, we examined whether the WNT/β-catenin pathway controls the tumor-related elevation of RUNX2 expression in osteosarcoma. We analyzed protein levels and nuclear localization of β-catenin and RUNX2 in a panel of human osteosarcoma cell lines (SAOS, MG63, U2OS, HOS, G292, and 143B). In all six cell lines, β-catenin and RUNX2 are expressed to different degrees and localized in the nucleus and/or cytoplasm. SAOS cells have the highest levels of RUNX2 protein that is localized in the nucleus, while MG63 cells have the lowest RUNX2 levels which is mostly localized in the cytoplasm. Levels of β-catenin and RUNX2 protein are enhanced in HOS, G292, and 143B cells after treatment with the GSK3β inhibitor SB216763. Furthermore, small interfering RNA (siRNA)-mediated depletion of β-catenin inhibits RUNX2 expression in G292 cells. Thus, WNT/β-catenin activation is required for RUNX2 expression in at least some osteosarcoma cell types, where RUNX2 is known to promote expression of metastasis related genes. J. Cell. Biochem. 118: 3662-3674, 2017. © 2017 Wiley Periodicals, Inc.

The genetic variations responsible for tumorigenesis are called driver mutations. In breast cancer (BC), two studies have demonstrated that germline mutations in driver genes linked to sporadic tumors may also influence BC risk. The present study evaluates the association between SNPs and SNP-SNP interaction in driver genes TTN (rs10497520), TBX3 (rs2242442), KMT2D (rs11168827), and MAP3K1 (rs702688 and rs702689) with BC risk in BRCA1/2-negative Chilean families. The SNPs were genotyped in 489 BC cases and 1078 controls by TaqMan Assay. Our data do not support an association between rs702688: A&gt, G or rs702689: G&gt, A and BC risk. The rs10497520-T allele was associated with a decreased risk in patients with family history of BC or early-onset BC (OR = 0.6, p &lt, 0.0001 and OR = 0.7, p = 0.05, respectively). rs2242442-G was associated with a protective effect and rs11168827-C was associated with increased BC risk in families with a strong history of BC (OR = 0.6, p = 0.02 and OR = 1.4, p = 0.05, respectively). As rs10497520-T and rs2242442-G seemed to protect against BC risk, we then evaluated their combined effect. Familial BC risk decreased in a dose-dependent manner with the protective allele count, reflecting an additive effect (p-trend &lt, 10&minus, 4). To our knowledge, this is the first association study of BC driver gene germline variations in a Chilean population.

Osteosarcoma is the most common bone tumor in children and adolescents (Young and Miller, 1975). The highest incidence of osteosarcoma is in the second decade of life, which suggests a relationship between bone growth and tumor development (Fraumeni, 1967; Cotterill et al., 2004). One of the critical steps for normal skeletal development and bone formation is the proliferative expansion of mesenchymal cells, osteoprogenitors, and immature osteoblasts. Cell growth and differentiation of normal osteoprogenitors and pre-osteoblasts is tightly regulated by Runx2, which favors a quiescent state (Pratap et al., 2003; Galindo et al., 2005). The growth suppressive potential of Runx2 is controlled by modulation of its protein levels during the cell cycle (Galindo et al., 2005, 2007). Cell cycle dependent changes of Runx2 levels occur with respect to G1 progression at a cell cycle stage when normal osteoblasts monitor extra-cellular cues for competency to initiate cell cycle progression beyond the G1/S phase transition. Accordingly, transient Runx2 overexpression in synchronized cells delays cell cycle entry into S phase and significantly decreases cell proliferation in the MC3T3 pre-osteoblasts, Runx2 null calvarian osteoprogenitors, C2C12 pluripotent mesenchymal, and IMR-90 fibroblasts cell lines (Pratap et al., 2003; Galindo et al., 2005; Young et al., 2007a; Teplyuk et al., 2008, 2009a). The function of Runx2 as a negative regulator of cell proliferation is also reflected by linkage of Runx2 deficiency to cell immortalization and tumorigenesis (Kilbey et al., 2007; Zaidi et al., 2007a). Apart from the growth suppressive potential that is evident during late G1 in osteoblasts (Pratap et al., 2003; Galindo et al., 2005), Runx2 may have mitogenic potential in early G1 (Teplyuk et al., 2008). Several studies indicate that Runx2-dependent control of proliferation is cell type-specific. Runx2 inhibits proliferation of osteoprogenitors and committed osteoblasts (Pratap et al., 2003; Galindo et al., 2005), but it may have distinct biological roles in chondrocytes (Galindo et al., 2005; Hinoi et al., 2006; Komori, 2008) and endothelial cells (Inman and Shore, 2003; Qiao et al., 2006). While immature osteoblasts from mice with Runx2 null mutations show accelerated proliferative potential, chondrocyte proliferation seems to be decreased in Runx2 null mice (Pratap et al., 2003; Yoshida et al., 2004), suggesting that Runx2 would also have opposites roles in different bone cell types. Moreover, ectopic expression of Runx2 in aortic endothelial cells increases cell proliferation (Sun et al., 2004), whereas Runx2 depletion inhibits cell proliferation in human marrow endothelial cells (Qiao et al., 2006). These findings support the concept that Runx2 protein can function as either a bona fide tumor suppressor or a classical oncoprotein depending on the cellular context (Blyth et al., 2005). Current evidence indicates that Runx2 expression is a key pathological factor in osteosarcoma (Martin et al., 2011) by controlling a number of cancer-related genes (van der Deen et al., 2012). Moreover, osteosarcoma development may be associated with Runx2 overexpression and defects in osteogenic differentiation (Wagner et al., 2011). Over-expression of Runx2 in transgenic mice within the osteoblast lineage inhibits osteoblast maturation, increases bone resorption, and causes osteopenia with multiple fractures (Liu et al., 2001; Geoffroy et al., 2002). Runx2 is also clearly detected in clinical osteosarcoma samples (Andela et al., 2005; Lu et al., 2008; Sadikovic et al., 2009; Won et al., 2009; Kurek et al., 2010). Analysis of genomic DNA from osteosarcoma patients with amplication of the 6p12#x02013;p21 chromosomal interval, which spans the Runx2 locus, increases the Runx2 gene copy number and aberrantly elevates Runx2 expression (Lau et al., 2004; Lu et al., 2008; Sadikovic et al., 2009). Increased expression of Runx2 in osteosarcoma biopsies has been associated to increased tumorigenicity, tumor progression, metastases, lower survival, and poor prognosis (Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Interestingly, osteosarcoma cell culture models may exhibit a similar variability of Runx2 gene expression, because Runx2 is expressed at different levels in a number of human osteosarcoma cell lines (Thomas et al., 2004; Lu et al., 2008; Luo et al., 2008; Kurek et al., 2010; Shapovalov et al., 2010). A subset of patient-derived osteosarcoma cell lines exhibit high levels of Runx2, whereas others show decreased Runx2 expression in accordance with the findings of Thomas and colleagues who suggested that Runx2 protein levels are negatively regulated in some types of osteosarcoma (Thomas et al., 2004; Nathan et al., 2009; Pereira et al., 2009; San Martin et al., 2009; Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Recently, we presented data indicating that cell cycle control of Runx2, which is readily observed in osteoblasts, is deregulated in osteosarcoma cells (Galindo et al., 2005; San Martin et al., 2009). Runx2 is constitutively expressed throughout the cell cycle in at least two osteosarcoma (human SaOS and rat ROS) cell lines (Young et al., 2007b; San Martin et al., 2009). Hence, the transcriptional and post-transcriptional mechanisms that mediate cell cycle control of Runx2 gene expression in osteoblasts could be compromised in osteosarcoma cells. The latter may occur in conjunction with abrogation of other molecular mechanisms cells that mediate normal osteoblast proliferation and that may bypass the growth suppressive properties of Runx2 in bone cancer cells (Nathan et al., 2009). In this article, we systematically examined human osteosarcoma cell lines with respect to Runx2 gene expression and cell cycle regulation to understand the biological functions of Runx2 in osteosarcoma cell proliferation. Our main finding is that forced expression of Runx2 suppresses growth in all cell lines, indicating that stimulation of Runx2 beyond its preestablished levels in osteosarcoma cells remains capable of triggering an anti-proliferative response. We propose that osteosarcoma cells in which Runx2 is present must balance prooncogenic functions of Runx2 with the requirement to maintain Runx2 at levels that avoid tumor suppression.

β-Catenin is crucial in the canonical Wnt signaling pathway. This pathway is up-regulated by CK2 which is associated with an enhanced expression of the antiapoptotic protein survivin, although the underlying molecular mechanism is unknown. AKT/PKB kinase phosphorylates and promotes β-catenin transcriptional activity, whereas CK2 hyperactivates AKT by phosphorylation at Ser129; however, the role of this phosphorylation on β-catenin transcriptional activity and cell survival is unclear. We studied in HEK-293T cells, the effect of CK2-dependent hyperactivation of AKT on cell viability, as well as analyzed β-catenin subcellular localization and transcriptional activity and survivin expression. CK2α overexpression led to an augmented β-catenin-dependent transcription and protein levels of survivin, and consequently an enhanced resistance to apoptosis. However, CK2α-enhancing effects were reversed when an AKT mutant deficient in Ser129 phosphorylation by CK2 was co-expressed. Therefore, our results strongly suggest that CK2α-specific enhancement of β-catenin transcriptional activity as well as cell survival may depend on AKT hyperactivation by CK2.

β-Catenin is a key protein in the canonical Wnt signaling pathway and in many cancers alterations in transcriptional activity of its components are observed. This pathway is up-regulated by the protein kinase CK2, but the underlying mechanism of this change is unknown. It has been demonstrated that CK2 hyperactivates AKT/PKB by phosphorylation at Ser129, and AKT phosphorylates β-catenin at Ser552, which in turn, promotes its nuclear localization and transcriptional activity. However, the consequences of CK2-dependent hyperactivation of AKT on β-catenin activity and cell viability have not been evaluated. We assessed this regulatory process by manipulating the activity of CK2 and AKT through overexpression of wild-type, constitutively active and dominant negative forms of these proteins as well as analyzing β-catenin-dependent transcriptional activity, survivin expression and viability in HEK-293T cells. We observed that CK2α overexpression up-regulated the β-catenin transcriptional activity, which correlated to an increased nuclear localization of β-catenin as well as survivin expression. Importantly, these effects were strongly reversed when an AKT-S129A mutant was co-expressed in the same cells, followed by a significant decrease in cell viability but no changes in β-catenin stability. Taken together, the data suggest that the CK2α-dependent up-regulation of β-catenin activity requires phosphorylation of AKT in human embryonic kidney cells. J. Cell. Physiol. 226: 1953–1959, 2011. © 2010 Wiley-Liss, Inc.

Introduction Enhanced radiosensitivity at low doses of ionising radiation (IR) (0.2 to 0.6 Gy) has been reported in several cell lines. This phenomenon, known as low doses hyper–radiosensitivity (LDHRS), appears as an opportunity to decrease toxicity of radiotherapy. However, this effect is subtle and the mechanism underlying LDHRS has not been clearly explained, limiting the benefit of LDHRS in clinical practice. Material and methods To determinate LDHRS in DLD–1 human colorectal cancer cells, viability, DNA damage, cell death and apoptosis were evaluated by: MTS, γ–H2AX immunofluorescence, trypan blue dye assays, Caspase 3/7 activity and hypoploidy determination; in cells exposed to low (0.6 Gy) and high (12 Gy) doses IR. LDHRS in DLD.-1 cells was confirmed by clonogenic assays and mathematical modelling. Then, to understand the mechanisms responsible for cell death induced by low-dose IR, we evaluated a panel of 86 miRNAs in array-PCR format. Validation of targets was made by qRT-PCR and functional assays were achieved by transient overexpression. Results and discussions Our results show that DLD–1 cells display LDHRS. Also, doses of 0.6 Gy induced an early but transient DNA damage response. miRNA expression assays revealed an overexpression of 3 microRNAs (miR-205–3 p, miR–1 and miR–133b) and down regulation of 2 miRNAs (miR–122–5 p, and miR–134–5 p). This miRNA profile differed from the one in cells exposed to high-dose IR (12 Gy). Transfection with mimetic of miR-205–3 p, the most overexpressed miRNA in cells exposed to 0.6 Gy, induced cell death at lower dose, increasing LDHRS response. Interestingly, at higher doses (12 Gy), miR–205–3 p induced formation of multi- and micronuclei, features associated with mitotic catastrophe. Thus, IR evoked differents miRNAs profiles, in agreement with a distinct low dose radiation-induced cell death mechanism. Moreover, MiR–205–3 p increased radiosentitivity by two-ways: at low doses, by apoptosis induction, and higher doses by mitotic catastrophe. This effect could be used to boost the outcome of IR, while decreasing therapeutic doses. Conclusion We propose miR-205–3 p as a potential radiosensitizer to low-dose IR. Acknowledgments This work was supported by grant Anillo ACT115, PIA Program, CONICYT, FONDECYT 1151435, 1160889 and the national doctoral fellowship 21130246 CONICYT

Oncogenic kinase Aurora A (AURKA) has been found to be overexpresed in several tumors including colorectal, breast, and hematological cancers. Overexpression of AURKA induces centrosome amplification and aneuploidy and it is related with cancer progression and poor prognosis. Here we show that AURKA phosphorylates in vitro the transcripcional co-repressor Ski on aminoacids Ser326 and Ser383. Phosphorylations on these aminoacids decreased Ski protein half-life. Reduced levels of Ski resulted in centrosomes amplification and multipolar spindles formation, same as AURKA overexpressing cells. Importantly, overexpression of Ski wild type, but not S326D and S383D mutants inhibited centrosome amplification and cellular transformation induced by AURKA. Altogether, these results suggest that the Ski protein is a target in the transformation pathway mediated by the AURKA oncogene.

Caveolin-1 is suggested to act as a tumor suppressor. We tested the hypothesis that caveolin-1 does so by repression of survivin, an Inhibitor of apoptosis protein that regulates cell-cycle progression as well as apoptosis and is commonly overexpressed in human cancers. Ectopic expression of caveolin-1 in HEK293T and ZR75 cells or siRNA-mediated silencing of caveolin-1 in NIH3T3 cells caused downregulation or upregulation of survivin mRNA and protein, respectively. Survivin downregulation in HEK293T cells was paralleled by reduced cell proliferation, increases in G0-G1 and decreases in G2-M phase of the cell cycle. In addition, apoptosis was evident, as judged by several criteria. Importantly, expression of green fluorescent protein-survivin in caveolin-1-transfected HEK293T cells restored cell proliferation and viability. In addition, expression of caveolin-1 inhibited transcriptional activity of a survivin promoter construct in a β-catenin-Tcf/Lef-dependent manner. Furthermore, in HEK293T cells caveolin-1 associated with β-catenin and inhibited Tcf/Lef-dependent transcription. Similar results were obtained upon caveolin-1 expression in DLD1 cells, where APC mutation leads to constitutive activation of β-catenin-Tcf/Lef-mediated transcription of survivin. Taken together, these results suggest that anti-proliferative and pro-apoptotic properties of caveolin-1 may be attributed to reduced survivin expression via a mechanism involving diminished β-catenin-Tcf/Lef-dependent transcription.

The protein kinase CK2 is constituted by two catalytic (alpha and/or alpha') and two regulatory (beta) subunits. CK2 phosphorylates more than 300 proteins with important functions in the cell cycle. This study has looked at the relation between CK2 and p27(KIP1), which is a regulator of the cell cycle and a known inhibitor of cyclin-dependent kinases (Cdk). We demonstrated that in vitro recombinant Xenopus laevis CK2 can phosphorylate recombinant human p27(KIP1), but this phosphorylation occurs only in the presence of the regulatory beta subunit. The principal site of phosphorylation is serine-83. Analysis using pull down and surface plasmon resonance (SPR) techniques showed that p27(KIP1) interacts with the beta subunit through two domains present in the amino and carboxyl ends, while CD spectra showed that p27(KIP1) phosphorylation by CK2 affects its secondary structure. Altogether, these results suggest that p27(KIP1) phosphorylation by CK2 probably involves a docking event mediated by the CK2beta subunit. The phosphorylation of p27(KIP1) by CK2 may affect its biological activity.

Background Germline mutations in PALB2 have been identified in approximately 1% of familial breast cancer (BC) in several populations. Nevertheless its contribution in the South-American population is unknown. The goal of this study was to determine the prevalence of PALB2 mutations in the Chilean population. Methods 100 Chilean BRCA1/2-negatives familial BC cases were included for the PALB2 mutation analysis. We use conformational sensitive gel electrophoresis and direct sequencing. Using a case-control design, we studied the identified variants in 436 BC cases and 809 controls to evaluate their possible association with BC risk. Results No pathogenic mutations were detected. We identified three variants, the variant c.1861C > A not previously described was found in one of the 436 cases and none of the 809 controls. The bioinformatic analyses indicate that this variant probably is not pathogenic. PALB2 c.1676A > G (rs152451A/G) and c.2993C > T (rs45551636C/T) variants were significantly associated with increased BC risk only in cases with a strong family history of BC (OR = 1.9 [CI 95% 1.3-2.8] p G and c.2993C > T play roles in BC risk in women with a strong family history of BC. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1033-3) contains supplementary material, which is available to authorized users.

The key protein in the canonical Wnt pathway is β-catenin, which is phosphorylated both in absence and presence of Wnt signals by different kinases. Upon activation in the cytoplasm, β-catenin can enter into the nucleus to transactivate target gene expression, many of which are cancer-related genes. The mechanism governing β-catenin's nucleocytoplasmic transport has been recently unvealed, although phosphorylation at its C-terminal end and its functional consequences are not completely understood. Serine 646 of β-catenin is a putative CK2 phosphorylation site and lies in a region which has been proposed to be important for its nucleocytoplasmic transport and transactivation activity. This residue was mutated to aspartic acid mimicking CK2-phosphorylation and its effects on β-catenin activity as well as localization were explored. β-Catenin S6464D did not show significant differences in both transcriptional activity and nuclear localization compared to the wild-type form, but displayed a characteristic granular nuclear pattern. Three-dimensional models of nuclei were constructed which showed differences in number and volume of granules, being those from β-catenin S646D more and smaller than the wild-type form. FRAP microscopy was used to compare nuclear export of both proteins which showed a slightly higher but not significant retention of β-catenin S646D. Altogether, these results show that C-terminal phosphorylation of β-catenin seems to be related with its nucleocytoplasmic transport but not transactivation activity.

Early in cancer development, tumour cells express vascular endothelial growth factor (VEGF), a secreted molecule that is important in all stages of angiogenesis, an essential process that provides nutrients and oxygen to the nascent tumor and thereby enhances tumor-cell survival and facilitates growth. Survivin, another protein involved in angiogenesis, is strongly expressed in most human cancers, where it promotes tumor survival by reducing apoptosis as well as favoring endothelial cell proliferation and migration. The mechanisms by which cancer cells induce VEGF expression and angiogenesis upon survivin up-regulation remain to be fully established. Since the PI3K/Akt signalling and β-catenin-Tcf/Lef dependent transcription have been implicated in the expression of many cancer-related genes, including survivin and VEGF, we evaluated whether survivin may favor VEGF expression, release from tumor cells and induction of angiogenesis in a PI3K/Akt-β-catenin-Tcf/Lef-dependent manner. Here, we provide evidence linking survivin expression in tumor cells to increased β-catenin protein levels, β-catenin-Tcf/Lef transcriptional activity and expression of several target genes of this pathway, including survivin and VEGF, which accumulates in the culture medium. Alternatively, survivin downregulation reduced β-catenin protein levels and β-catenin-Tcf/Lef transcriptional activity. Also, using inhibitors of PI3K and the expression of dominant negative Akt, we show that survivin acts upstream in an amplification loop to promote VEGF expression. Moreover, survivin knock-down in B16F10 murine melanoma cells diminished the number of blood vessels and reduced VEGF expression in tumors formed in C57BL/6 mice. Finally, in the chick chorioallantoid membrane assay, survivin expression in tumor cells enhanced VEGF liberation and blood vessel formation. Importantly, the presence of neutralizing anti-VEGF antibodies precluded survivin-enhanced angiogenesis in this assay. These findings provide evidence for the existance of a posititve feedback loop connecting survivin expression in tumor cells to PI3K/Akt enhanced β-catenin-Tcf/Lef-dependent transcription followed by secretion of VEGF and angiogenesis. Electronic supplementary material The online version of this article (doi:10.1186/1476-4598-13-209) contains supplementary material, which is available to authorized users.

We previously found that the small GTPase Rheb regulates the cell-cycle inhibitor p27KIP1 (p27) in colon cancer cells by a mTORC1-independent mechanism. However, the biological function of the Rheb/p27 axis in cancer cells remains unknown. Here, we show that siRNA-mediated depletion of Rheb decreases survival of human colon cancer cells under serum deprivation. As autophagy can support cell survival, we analyzed the effect of Rheb on this process by detecting the modification of the autophagy marker protein LC3 by western blot and imunofluorescence. We found that Rheb promotes autophagy in several human cancer cell lines under serum deprivation. Accordingly, blocking autophagy inhibited the pro-survival effect of Rheb in colon cancer cells. We then analyzed whether p27 was involved in the biological effect of Rheb. Depletion of p27 inhibited colon cancer cell survival, and Rheb induction of autophagy. These results suggest that p27 has an essential role in the effect of Rheb in response to serum deprivation. In addition, we demonstrated that the role of p27 in autophagy stands on the N-terminal portion of the protein, where the CDK-inhibitory domain is located. Our results indicate that a Rheb/p27 axis accounts for the activation of autophagy that supports cancer cell survival. Our work therefore highlights a biological function of Rheb and prompts the need for future studies to address whether the mTORC1-independent Rheb/p27 axis could contribute to tumorigenesis and/or resistance to mTOR inhibitors.