ERK Signals: Scaffolding Scaffolds?

ERK1/2 MAP Kinases become activated in response to multiple intra- and extra-cellular stimuli through a signaling module composed of sequential tiers of cytoplasmic kinases. Scaffold proteins regulate ERK signals by connecting the different components of the module into a multi-enzymatic complex by which signal amplitude and duration are fine-tuned, and also provide signal fidelity by isolating this complex from external interferences. In addition, scaffold proteins play a central role as spatial regulators of ERKs signals. In this respect, depending on the subcellular localization from which the activating signals emanate, defined scaffolds specify which substrates are amenable to be phosphorylated. Recent evidence has unveiled direct interactions among different scaffold protein species. These scaffold-scaffold macro-complexes could constitute an additional level of regulation for ERK signals and may serve as nodes for the integration of incoming signals and the subsequent diversification of the outgoing signals with respect to substrate engagement.PC lab is supported by grants BFU2011-23807 and SAF-2015 63638R (MINECO/FERDER, UE) from the Spanish Ministry of Economy – Fondos FEDER; by the Red Temática de Investigación Cooperativa en Cáncer (RTICC) (RD/12/0036/0033), Spanish Ministry of Health and by Asociación Española Contra el Cáncer (AECC), grant GCB141423113. BC is a CSIC JAE-Doc program postdoctoral fellow supported by the European Social Fund.Peer reviewedPeer Reviewe

Método para predecir la respuesta terapéutica a fármacos inhibidores de la serina-treonina kinasa BRAF

La presente invención se refiere a un método in vitro que permite predecir la respuesta terapéutica al tratamiento con fármacos inhibidores de BRAF, tales como vemurafenib, en pacientes de cáncer asociado a mutaciones oncogénicas en dicha kinasa, tal como melanoma BRAF positivo. Dicho método se basa en la medición de los niveles de ERK1/2 citoplasmática, a través de la detección y cuantificación de ERK1/2 fosforiladas en serina 301/284 respectivamente, en una muestra biológica aislada del paciente. La invención también proporciona un anticuerpo específico frente a ERK1/2 fosforiladas en serina 301/284 y un kit que lo comprende, los cuales son de utilidad en el método descrito.Solicitud: 201930419 (13.05.2019)Nº Pub. de Solicitud: ES2793801A1 (16.11.2020

Fast regulation of AP-1 activity through interaction of lamin A/C, ERK1/2, and c-Fos at the nuclear envelope

Sequestration of c-Fos at the nuclear envelope (NE) through interaction with A-type lamins suppresses AP-1–dependent transcription. We show here that c-Fos accumulation within the extraction-resistant nuclear fraction (ERNF) and its interaction with lamin A are reduced and enhanced by gain-of and loss-of ERK1/2 activity, respectively. Moreover, hindering ERK1/2-dependent phosphorylation of c-Fos attenuates its release from the ERNF induced by serum and promotes its interaction with lamin A. Accordingly, serum stimulation rapidly releases preexisting c-Fos from the NE via ERK1/2-dependent phosphorylation, leading to a fast activation of AP-1 before de novo c-Fos synthesis. Moreover, lamin A–null cells exhibit increased AP-1 activity and reduced levels of c-Fos phosphorylation. We also find that active ERK1/2 interacts with lamin A and colocalizes with c-Fos and A-type lamins at the NE. Thus, NE-bound ERK1/2 functions as a molecular switch for rapid mitogen-dependent AP-1 activation through phosphorylation-induced release of preexisting c-Fos from its inhibitory interaction with lamin A/C

Ras subcellular localization inversely regulates thyroid tumor growth and dissemination

RAS mutations are the second most common genetic alteration in thyroid tumors. However, the extent to which they are associated with the most aggressive phenotypes is still controversial. Regarding their malignancy, the majority of RAS mutant tumors are classified as undetermined, which complicates their clinical management and can lead to undesired under-or overtreatment. Using the chick embryo spontaneous metastasis model, we herein demonstrate that the aggressiveness of HRAS-transformed thyroid cells, as determined by the ability to extravasate and metastasize at distant organs, is orchestrated by HRAS subcellular localization. Remarkably, aggressiveness inversely correlates with tumor size. In this respect, we also show that RAS sitespecific capacity to regulate tumor growth and dissemination is dependent on VEGF-B secretion. Furthermore, we have identified the acyl protein thioesterase APT-1 as a determinant of thyroid tumor growth versus dissemination. We show that alterations in APT-1 expression levels can dramatically affect the behavior of thyroid tumors, based on its role as a regulator of HRAS sublocalization at distinct plasma membrane microdomains. In agreement, APT-1 emerges in thyroid cancer clinical samples as a prognostic factor. As such, APT-1 levels could serve as a biomarker that could help in the stratification of HRAS mutant thyroid tumors based on their aggressiveness.PC lab is supported by grant RTI2018-096658B-100 from the Spanish Ministry of Science (MICIU/AEI/FEDER, UE). Santisteban, Riesco and Crespo Laboratories are supported jointly by grants from Asociación Española Contra el Cancer (AECC; GCB141423113) and CIBERONC from the Instituto de Salud Carlos III (ISCIII). PS acknowledges support from: SAF2016-75531-R (MINECO/FEDER, UE); B2017/BMD-3724 Tironet2 (Comunidad de Madrid) and PID2019-105303RB-I00/AEI/10.13039/501100011033 from Ministerio de Ciencia e Innovación (MICIN). B.C is funded by Retos Jóvenes Investigadores grant SAF2015-73364-JIN (MICIU/AEI/FEDER, UE), a PIE grant from Consejo Superior de Investigaciones Científicas (CSIC)- MICIU and the Ramón y Cajal Research Program (MICIU, RYC2018-024004-I)

Extending the applicability of in ovo and ex ovo chicken chorioallantoic membrane assays to study cytostatic activity in neuroblastoma cells

Purpose The chick chorioallantoic membrane (CAM) assay can provide an alternative versatile, cost-effective, and ethically less controversial in vivo model for reliable screening of drugs. In the presented work, we demonstrate that CAM assay (in ovo and ex ovo) can be simply employed to delineate the effects of cisplatin (CDDP) and ellipticine (Elli) on neuroblastoma (Nbl) cells in terms of their growth and metastatic potential. Methods The Nbl UKF-NB-4 cell line was established from recurrent bone marrow metastases of high-risk Nbl (stage IV, MYCN amplification, 7q21 gain). Ex ovo and in ovo CAM assays were optimized to evaluate the antimetastatic activity of CDDP and Elli. Immunohistochemistry, qRT-PCR, and DNA isolation were performed. Results Ex ovo CAM assay was employed to study whether CDDP and Elli exhibit any inhibitory effects on growth of Nbl xenograft in ex ovo CAM assay. Under the optimal conditions, Elli and CDDP exhibited significant inhibition of the size of the primary tumor. To study the efficiency of CDDP and Elli to inhibit primary Nbl tumor growth, intravasation, and extravasation in the organs, we adapted the in ovo CAM assay protocol. In in ovo CAM assay, both studied compounds (CDDP and Elli) exhibited significant (p < 0.001) inhibitory activity against extravasation to all investigated organs including distal CAM. Conclusions Taken together, CAM assay could be a helpful and highly efficient in vivo approach for high-throughput screening of libraries of compounds with expected anticancer activities

RAS at the Golgi antagonizes malignant transformation through PTPRκ-mediated inhibition of ERK activation

© The Author(s) 2018.RAS GTPases are frequently mutated in human cancer. H- and NRAS isoforms are distributed over both plasma-membrane and endomembranes, including the Golgi complex, but how this organizational context contributes to cellular transformation is unknown. Here we show that RAS at the Golgi is selectively activated by apoptogenic stimuli and antagonizes cell survival by suppressing ERK activity through the induction of PTPRκ, which targets CRAF for dephosphorylation. Consistently, in contrast to what occurs at the plasma-membrane, RAS at the Golgi cannot induce melanoma in zebrafish. Inactivation of PTPRκ, which occurs frequently in human melanoma, often coincident with TP53 inactivation, accelerates RAS-ERK pathway-driven melanomagenesis in zebrafish. Likewise, tp53 disruption in zebrafish facilitates oncogenesis driven by RAS from the Golgi complex. Thus, RAS oncogenic potential is strictly dependent on its sublocalization, with Golgi complex-located RAS antagonizing tumor development.We are grateful to Drs: Ignacio Rubio, Yardena Samuels, Mariano Barbacid and Javier León for providing reagents; and Alicia Noriega, Sandra Zunzunegui y Victor Campa for technical support. Crespo laboratory is supported by grant SAF-2015 63638R (MINECO/ FEDER, UE); by Red Temática de Investigación Cooperativa sobre el Cáncer (RTICC). RD/12/0036/0033 and by Asociación Española Contra el Cáncer (AECC), grant GCB141423113. Work in the Hurlstone laboratory was unded by a grant from the European Research Council (ERC-2011-StG-282059 PROMINENT). B.C. is supported by a Retos Jóvenes Investigadores grant SAF2015-73364-JIN (AEI/FEDER, UE) and a grant from Fundación Francisco Cobos. X.R.B. is supported by grants from the CastillaLeón Government (BIO/SA01/15, CSI049U16), MINECO (SAF2015-64556-R, RD12/ 0036/0002), Worldwide Cancer Research (14-1248), Ramón Areces Foundation, andAECC (GC16173472GARC). Spanish funding to P.C., B.C., and X.R.B. is partially supported by the European Regional Development Fund

Scaffold coupling: ERK activation by trans-phosphorylation across different scaffold protein species.

RAS-ERK (extracellular signal-regulated kinase) pathway signals are modulated by scaffold proteins that assemble the components of different kinase tiers into a sequential phosphorylation cascade. In the prevailing model scaffold proteins function as isolated entities, where the flux of phosphorylation events progresses downstream linearly, to achieve ERK phosphorylation. We show that different types of scaffold proteins, specifically KSR1 (kinase suppressor of Ras 1) and IQGAP1 (IQ motif-containing guanosine triphosphatase activating protein 1), can bind to each other, forming a complex whereby phosphorylation reactions occur across both species. MEK (mitogen-activated protein kinase kinase) bound to IQGAP1 can phosphorylate ERK docked at KSR1, a process that we have named trans-phosphorylation. We also reveal that ERK trans-phosphorylation participates in KSR1-regulated adipogenesis, and it also underlies the modest cytotoxicity exhibited by KSR-directed inhibitors. Overall, we identify interactions between scaffold proteins and trans-phosphorylation as an additional level of regulation in the ERK cascade, with broad implications in signaling and the design of scaffold protein-aimed therapeutics

ERK1/2 MAP kinases promote cell cycle entry by rapid, kinase-independent disruption of retinoblastoma–lamin A complexes

When in the nucleus, ERK1/2 dislodges the retinoblastoma protein from lamin A, facilitating its rapid phosphorylation

MO38-2 Metallothionein-3: Potential therapeutic target for sorafenib resistance in hepatocellular carcinoma

1 p. JSMO2021 Virtual Congress. 2021 the Japanese Society of Medical Oncology Annual Meeting. February 18 - 21, 2021Background: Metallothionein-3 (M-3) has poorly characterized functions in hepatocellular carcinoma (HCC). HCC is a significant health problem. Globally is the second most common cause of cancer-associated death. Sorafenib was originally identified as an inhibitor of multiple oncogenic kinases and remains the only approved systemic therapy for advanced HCC. However, acquired resistance to sorafenib has been found in HCC patients, which results in poor prognosis. Overexpression of MT-3 decreased the sensitivity of HCC cells to sorefenib. Here, we investigated the impact of MT-3 up-regulation in HCC cells and the mechanisms underlying the sorafenib-resistance.Methods: To increase the expression of MT-3 HCC cells were transiently transfected with a plasmid containing MT-3 gene or with empty vector. The cDNA microarrays were accomplished using the ElectraSenseTM Reader. MS analysis was performed using a Q-Exactive MS. We used chick chorioallantoic membrane assay as in vivo model.Results: A cDNA profiling revealed that sorafenib resistance has a specific transcriptomic signature involving genes responsible for ion transport, trafficking and DNA repair. Also, The MS analysis data strongly suggest that resistance HCC cells acquired a complex regulatory network that significantly affects the ability of HCC cells to remove the ROS and activation of glycolysis. We provide the first evidence that up-regulation of MT3 resulted in increased dissociation, invasion, and intravasation from the primary tumours to the veins. In addition, MT3 profoundly impacted blood migration of Nbl cells and their extravasation to chicken organs.Conclusion: From a perspective of future utilization of our data, we anticipate that several identified genes and proteins could serve as prognostic biomarkers of outcome of sorafenib therapy. The increased expression of MT-3 within tumour mass should inform about worse prognosis and also decreased efficiency of sorafenib-based chemotherapy in HCC.Peer reviewe

ARID2 deficiency promotes tumor progression and is associated with higher sensitivity to chemotherapy in lung cancer

The survival rate in lung cancer remains stubbornly low and there is an urgent need for the identification of new therapeutic targets. In the last decade, several members of the SWI/SNF chromatin remodeling complexes have been described altered in different tumor types. Nevertheless, the precise mechanisms of their impact on cancer progression, as well as the application of this knowledge to cancer patient management are largely unknown. In this study, we performed targeted sequencing of a cohort of lung cancer patients on genes involved in chromatin structure. In addition, we studied at the protein level the expression of these genes in cancer samples and performed functional experiments to identify the molecular mechanisms linking alterations of chromatin remodeling genes and tumor development. Remarkably, we found that 20% of lung cancer patients show ARID2 protein loss, partially explained by the presence of ARID2 mutations. In addition, we showed that ARID2 deficiency provokes profound chromatin structural changes altering cell transcriptional programs, which bolsters the proliferative and metastatic potential of the cells both in vitro and in vivo. Moreover, we demonstrated that ARID2 deficiency impairs DNA repair, enhancing the sensitivity of the cells to DNA-damaging agents. Our findings support that ARID2 is a bona fide tumor suppressor gene in lung cancer that may be exploited therapeutically.Financial Support: I. V. is supported by SAF2012-31627 and SAF2016-76758-R grants from the Spanish Ministerio de Economía y Competitividad (MINECO), by a Fundación Ramón Areces grant and by ERC2014-StG637904 grant from the European Research Council. I. V has been awardee of the Programa Ramón y Cajal (MINECO, Spain). T. M has been awardee of the Ayudas para la contratación de investigadores predoctorales (MINECO, Spain). B. M is awardee of the Ayudas para la formación de profesorado universitario (FPU, Ministerio de Educación y Formación Profesional, Spain). PC laboratory is supported by grant SAF-2015-63638R (MINECO/FEDER, UE); by Centro de Investigación Biomédica en Red de Cáncer (CIBERONC) and by Asociación Española Contra el Cáncer (AECC), grant GCB141423113. BC has been supported by a Retos Jóvenes Investigadores grant SAF2015-73364-JIN (AEI/FEDER, UE) and a grant from Fundación Francisco Cobos. P. S. is supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001152), the UK Medical Research Council (FC001152). HUCA/IUOPA which is jointly financed by Servicio de Salud del Principado de Asturias, Instituto de Salud Carlos III and Fundación Bancaria Cajastur. This research was funded in part by the Wellcome Trust [FC001152]