Dual inhibition of V600EBRAF and the PI3K/AKT/mTOR pathway cooperates to induce apoptosis in melanoma cells through a MEK-independent mechanism

BRAF is a main oncogene in human melanomas. Here, we show that BRAF depletion by siRNA or inhibition of its activity by treatment with RAF inhibitor Sorafenib induces apoptosis in NPA melanoma cells expressing oncogenic (V600E)BRAF. This effect is mediated through a MEK/ERK-independent mechanism, since treatment with the MEK inhibitor U0126 does not exert any effect. Moreover, we demonstrate that inhibition of the PI3K/AKT/mTOR cascade alone does not increase apoptosis in these cells. However, the blockage of this pathway in cells lacking either BRAF expression or activity cooperates to induce higher levels of apoptosis than those achieved by inhibition of BRAF alone. Consistently, we demonstrate that abrogation of BRAF expression increases AKT and mTOR phosphorylation, suggesting the existence of a compensatory pro-survival mechanism after BRAF depletion. Together, our data provide a rationale for dual targeting of BRAF and PI3K/AKT/mTOR signalling to effectively control melanoma disease

Oncogenic Ras, but not V600EB-RAF, protects from cholesterol depletion-induced apoptosis through the PI3K/AKT pathway in colorectal cancer cells

Cholesterol is necessary for proliferation and survival of transformed cells. Here we analyse the effect of cholesterol depletion on apoptosis and the mechanisms underlying this effect in colorectal cancer cells carrying oncogenic Ras or B-V600E-RAF mutations. We show that chronic cholesterol depletion achieved with lipoprotein-deficient serum (LPDS) and 25-hydroxycholesterol (25-HC) treatment results in a significant increase in apoptosis in HT-29 and Colo-205 cells containing the B-V600E-RAF mutation, but not in HCT-116 and LoVo cells harbouring the (G13D)Ras mutation, or BE cells, which possess two mutations, (G13D)Ras and B-G463V-RAF. We also demonstrate that oncogenic Ras protects from apoptosis induced by cholesterol depletion through constitutive activation of the phosphatidylinositol-3 kinase (PI3K)/AKT pathway. The specific activation of the PI3K/AKT pathway by overexpression of the (V12)RasC40 mutant or a constitutively active AKT decreases the LPDS plus 25-HC-induced apoptosis in HT-29 cells, whereas PI3K inhibition or abrogation of AKT expression renders HCT-116 sensitive to cholesterol depletion-induced apoptosis. Moreover, our data show that LPDS plus 25-HC increases the activity of c-Jun N-terminal kinase proteins only in HT-29 cells and that the inhibition of this kinase blocks the apoptosis induced by LPDS plus 25-HC. Finally, we demonstrate that AKT hyperactivation by oncogenic Ras protects from apoptosis, preventing the activation of c-Jun N-terminal kinase by cholesterol depletion. Thus, our data demonstrate that low levels of cholesterol induce apoptosis in colorectal cancer cells without oncogenic Ras mutations. These results reveal a novel molecular characteristic of colon tumours containing Ras or B-RAF mutations and should help in defining new targets for cancer therapy

Integra BioFis 5.0. A collaborative, participatory and interdisciplinary experience for undergraduates in nursing

The pandemic has forced us to reinvent ourselves and to consider new strategies in education. Motivation, fundamental to student performance, has been seriously compromised. In this sense, the type of motivation we are interested in "fostering" is intrinsic motivation, closely linked to the concept of learning-centered goals and objectives. The action implemented is committed to the approach to challenge-based learning-gamification in the Degree in Nursing (UAH), in order to develop an integrative training with an interdisciplinary focus. Biochemistry and Physiology came together in Integra BioFis 5.0 and through participatory and collaborative techniques we pursued meaningful learning. All the students of the Biochemistry and Physiology subjects (n = 120) took part in the learning experience, organized in 12 teams. The action was carried out online through the virtual platform: - An initial session, in which the objectives, methodology, timetable and evaluation criteria were clarified. Topics that aroused the students? interest were randomly assigned (https://bit.ly/3tfJaCi). The assigned tutors guided the students in overcoming the challenges of each stage. - The development of the action consisted of a series of phases: i) documentation and literature search; ii) integration of objectives and choice of presentation format; iii) elaboration of the graphical document; iv) peer review of presentations and voting for the best contribution. The students' papers, as well as the rubrics with comments and suggestions from each of the instructors, were returned to the teams immediately. - A final session, in which they reflected on the activity they had carried out, highlighting the positive aspects of the training for the development of competences and skills: i) search for information from quality sources; ii) synthesis of contents; iii) work as a team; iv) elaboration of an original and own work. Voting was then shown for the papers presented, revealing the names of the three teams with the most votes, finalists and winners. Learning assessment was conducted by taking into account the influence of learning on motivation and the student's self-esteem and competences, with indicators such as progress, content, sources, graphical document production, teamwork and responsibility, among others. As an important element that makes gamification work, a reward for participation (awarding of a participation diploma) and for the best Integra BioFis 5.0 graphic document presented (awarding of diplomas and prizes-gifts to the members of the winning team) was considered as an important element that makes gamification work. From this educational strategy, it can be concluded that gamification is a constructive experience, taking advantage of all the benefits of implementing the overcoming of challenges in the educational environment. This has had an impact on teaching practice, to the extent that what has been "reflected" and "worked" in Integra BioFis 5.0 has contributed to improving the quality of virtual teaching, "fostering" intrinsic motivation in students.Universidad de Alcal

A novel real-time PCR assay for quantitative detection of Campylobacter fetus based on ribosomal sequences

Background: Campylobacter fetus is a pathogen of major concern for animal and human health. The species shows a great intraspecific variation, with three subspecies: C. fetus subsp. fetus, C. fetus subsp. venerealis, and C. fetus subsp. testudinum. Campylobacter fetus fetus affects a broad range of hosts and induces abortion in sheep and cows. Campylobacter fetus venerealis is restricted to cattle and causes the endemic disease bovine genital campylobacteriosis, which triggers reproductive problems and is responsible for major economic losses. Campylobacter fetus testudinum has been proposed recently based on genetically divergent strains isolated from reptiles and humans. Both C. fetus fetus and C. fetus testudinum are opportunistic pathogens for immune-compromised humans. Biochemical tests remain as the gold standard for identifying C. fetus but the fastidious growing requirements and the lack of reliability and reproducibility of some biochemical tests motivated the development of molecular diagnostic tools. These methods have been successfully tested on bovine isolates but fail to detect some genetically divergent strains isolated from other hosts. The aim of the present study was to develop a highly specific molecular assay to identify and quantify C. fetus strains. Results: We developed a highly sensitive real-time PCR assay that targets a unique region of the 16S rRNA gene. This assay successfully detected all C. fetus strains, including those that were negative for the cstA gene-based assay used as a standard for molecular C. fetus identification. The assay showed high specificity and absence of cross-reactivity with other bacterial species. The analytical testing of the assay was determined using a standard curve. The assay demonstrated a wide dynamic range between 102 and 107 genome copies per reaction, and a good reproducibility with small intra- and inter-assay variability. Conclusions: The possibility to characterize samples in a rapid, sensitive and reproducible way makes this assay a good option to establish a new standard in molecular identification and quantification of C. fetus species.EEA BalcarceFil: Iraola, Gregorio. Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva; Uruguay. Institut Pasteur Montevideo. Unidad de Bioinformática; UruguayFil: Pérez, Ruben. Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva; UruguayFil: Betancor, Laura. Universidad de la República. Facultad de Medicina. Instituto de Higiene. Departamento de Bacteriología y Virología; UruguayFil: Marandino, Ana. Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva; UruguayFil: Morsella, Claudia Graciela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Laboratorio de Bacteriología. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Mendez, Maria Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Laboratorio de Bacteriología. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Paolicchi, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Laboratorio de Bacteriología. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Piccirillo, Alessandra. Università degli Studi di Padova. Dipartimento di Biomedicina Comparata e Alimentazione; ItaliaFil: Tomás, Gonzalo. Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva; UruguayFil: Velilla, Alejandra Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Laboratorio de Bacteriología. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Calleros, Lucía. Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva; Urugua

A novel real-time PCR assay for quantitative detection of Campylobacter fetus based on ribosomal sequences

Background: Campylobacter fetus is a pathogen of major concern for animal and human health. The species shows a great intraspecific variation, with three subspecies: C. fetus subsp. fetus, C. fetus subsp. venerealis, and C. fetus subsp. testudinum. Campylobacter fetus fetus affects a broad range of hosts and induces abortion in sheep and cows. Campylobacter fetus venerealis is restricted to cattle and causes the endemic disease bovine genital campylobacteriosis, which triggers reproductive problems and is responsible for major economic losses. Campylobacter fetus testudinum has been proposed recently based on genetically divergent strains isolated from reptiles and humans. Both C. fetus fetus and C. fetus testudinum are opportunistic pathogens for immune-compromised humans. Biochemical tests remain as the gold standard for identifying C. fetus but the fastidious growing requirements and the lack of reliability and reproducibility of some biochemical tests motivated the development of molecular diagnostic tools. These methods have been successfully tested on bovine isolates but fail to detect some genetically divergent strains isolated from other hosts. The aim of the present study was to develop a highly specific molecular assay to identify and quantify C. fetus strains. Results: We developed a highly sensitive real-time PCR assay that targets a unique region of the 16S rRNA gene. This assay successfully detected all C. fetus strains, including those that were negative for the cstA gene-based assay used as a standard for molecular C. fetus identification. The assay showed high specificity and absence of cross-reactivity with other bacterial species. The analytical testing of the assay was determined using a standard curve. The assay demonstrated a wide dynamic range between 102 and 107 genome copies per reaction, and a good reproducibility with small intra- and inter-assay variability. Conclusions: The possibility to characterize samples in a rapid, sensitive and reproducible way makes this assay a good option to establish a new standard in molecular identification and quantification of C. fetus species

Integrin Linked Kinase (ILK) Downregulation as an Early Event During the Development of Metabolic Alterations in a Short-Term High Fat Diet Mice Model.

Background/Aims: Diabetes type 2, metabolic syndrome or non-alcoholic fatty liver disease are insulin resistance-related metabolic disorders, which lack a better prognosis before their full establishment. We studied the importance of the intracellular scaffold protein integrin linked kinaes (ILK) as a key modulator in the initial pathogenesis and the early progression of those insulin resistance- related disorders. Methods: Adult mice with a global transgenic downregulation of ILK expression (cKD-ILK) and littermates without that depletion (CT) were fed with either standard (STD) or high fat (HFD) diets during 2 and 6 weeks. Weights, blood glucose and other systemic biochemical parameters were determined in animals under fasting conditions and after glucose or pyruvate intraperitoneal injections to test their tolerance. In RNA or proteins extracted from insulin-sensitive tissues, we determined by reverse transcription?quantitative PCR and western blot the expression of ILK, metabolites transporters and other metabolism and inflammatory markers. Glucose uptake capacity was studied in freshly isolated tissues. Results: HFD feeding was able to early and progressively increase glycaemia, insulinemia, circulating glycerol, body weight gain, liver-mediated gluconeogenesis along this time lapse, but cKD-ILK have all these systemic misbalances exacerbated compared to CT in the same HFD time lapse. Interestingly, the tisular expression of ILK in HFD-fed CT was dramatically downregulated in white adipose tissue (WAT), skeletal muscle and liver at the same extent of the original ILK downregulation of cKD-ILK. We previously published that basal STD-fed cKD-ILK compared to basal STD-CT have different expression of glucose transporters GLUT4 in WAT and skeletal muscle. In the same STD-fed cKD-ILK, we observed here the increased expressions of hepatic GLUT2 and WAT pro-inflammatory cytokines TNF-? and MCP-1. The administration of HFD exacerbated the expression changes in cKD-ILK of these and other markers related to the imbalanced metabolism observed, such as WAT lipolysis (HSL), hepatic gluconeogenesis (PCK-1) and glycerol transport (AQP9). Conclusion: ILK expression may be taken as a predictive determinant of metabolic disorders establishment, because its downregulation seems to correlate with the early imbalance of glucose and glycerol transport and the subsequent loss of systemic homeostasis of these metabolites.Instituto de Salud Carlos III-ISCIIIComunidad de MadridFondo Europeo de Desarrollo Regional-FEDERInstituto Ramon y Cajal de Investigación Sanitária-IRYCISFundación Renal Iñigo Álvarez de Toledo-FRIA

The Integrin Beta1 Modulator Tirofiban Prevents Adipogenesis and Obesity by the Overexpression of Integrin-Linked Kinase: a Pre-Clinical Approach In Vitro and In Vivo

de Frutos, S., Griera, M., Hatem-Vaquero, M. et al. The integrin beta1 modulator Tirofiban prevents adipogenesis and obesity by the overexpression of integrin-linked kinase: a pre-clinical approach in vitro and in vivo. Cell Biosci 12, 10 (2022)Background: Obesity is caused by the enlargement of the white adipose tissue (WAT) depots, characterized by the hypertrophic enlargement of malfunctioning adipocytes within WAT which increases the storage of triglycerides (TG) in the lipid droplets (LD). Adipogenesis pathways as well as the expression and activity of some extracellular matrix receptors integrins are upregulated. Integrin?1 (INTB1) is the main isoform involved in WAT remodeling during obesity and insulin resistance-related diseases. We recently described Integrin Linked Kinase (ILK), a scafold protein recruited by INTB1, as an important mediator of WAT remodeling and insulin resistance. As the few approved drugs to fght obesity have brought long-term cardiovascular side efects and given that the consideration of INTB1 and/or ILK modulation as anti-obesogenic strategies remains unexplored, we aimed to evaluate the anti-obesogenic capacity of the clinically approved anticoagulant Tirofban (TF), stated in preclinical studies as a cardiovascular protector. Methods: Fully diferentiated adipocytes originating from C3H10T1/2 were exposed to TF and were co-treated with specifc INTB1 blockers or with siRNA-based knockdown ILK expression. Lipid-specifc dyes were used to determine the TG content in LD. The genetic expression pattern of ILK, pro-infammatory cytokines (MCP1, IL6), adipogenesis (PPAR?, Leptin), thermogenesis (UCP1), proliferation (PCNA), lipid metabolism (FASN, HSL, ATGL), and metabolite trans porters (FABP4, FAT, AQP7) were detected using quantitative PCR. Cytoskeletal actin polymerization was detected by confocal microscopy. Immunoblotting was performed to detect INTB1 phosphorylation at Thr788/9 and ILK activity as phosphorylation levels of protein kinase B (AKT) in Ser473 and glycogen synthase kinase 3? (GSK3?) at Ser9. TF was intraperitoneally administered once per day to wildtype and ILK knockdown mice (cKDILK) challenged with a high-fat diet (HFD) or control diet (STD) for 2 weeks. Body and WAT weight gains were compared. The expression of ILK and other markers was determined in the visceral epididymal (epi) and inguinal subcutaneous (sc) WAT. Results: TF reduced TG content and the expression of adipogenesis markers and transporters in adipocytes, while UCP-1 expression was increased and the expression of lipases, cytokines or PCNA was not afected. Mechanistically, TF rapidly increased and faded the intracellular phosphorylation of INTB1 but not AKT or GSK3?. F-actin levels were rapidly decreased, and INTB1 blockade avoided the TF efect. After 24 h, ILK expression and phosphorylation rates of AKT and GSK3? were upregulated, while ILK silencing increased TG content. INTB1 blockade and ILK silencing avoided TF efects on the TG content and the transcriptional expression of PPAR? and UCP1. In HFD-challenged mice, the systemic administration of TF for several days reduced the weight gain on WAT depots. TF reduced adipogenesis and pro-infammatory biomarkers and increased lipolysis markers HSL and FAT in epiWAT from HFD, while increased UCP1 in scWAT. In both WATs, TF upregulated ILK expression and activity, while no changes were observed in other tissues. In HFD-fed cKDILK, the blunted ILK in epiWAT worsened weight gain and avoided the anti-obesogenic efect of in vivo TF administration. Conclusions: ILK downregulation in WAT can be considered a biomarker of obesity establishment. Via an INTB1-ILK axis, TF restores malfunctioning hypertrophied WAT by changing the expression of adipocyte-related genes, increas ing ILK expression and activity, and reducing TG storage. TF prevents obesity, a property to be added to its anticoagu lant and cardiovascular protective advantages.Instituto de Salud Carlos IIIComunidad de MadridFondo Europeo de Desarrollo Regional-FEDE

H- ras deletion protects against angiotensin II-induced arterial hypertension and cardiac remodeling through protein kinase G-Ibeta pathway activation

15 p.Ras proteins regulate cell survival, growth, differentiation, blood pressure, and fibrosis in some organs.We have demonstrated that H-rasgene deletion produces mice hypotensionviaa soluble guanylate cyclase-proteinkinase G (PKG)–dependent mechanism. In this study, we analyzed the consequences of H-rasdeletiononcardiacremodeling induced by continuous angiotensin II (AngII) infusion and the molecular mechanisms implied. Leftventricular posterior wall thickness and mass and cardiomyocyte cross-sectional area were similar between AngII-treated H-Ras knockout (H-ras2/2) and control wild-type (H-ras+/+) mice, as were extracellular matrix proteinexpression. Increased cardiac PKG-Ibprotein expression in H-ras2/2mice suggests the involvement of this proteinin heart protection.Ex vivoexperiments on cardiac explants could support this mechanism, as PKG blockadeblunted protection against AngII-induced cardiac hypertrophy and fibrosis markers in H-ras2/2mice. Geneticmodulation studies in cardiomyocytes and cardiac and embryonic fibroblasts revealed that the lack of H-Ras down-regulates the B-RAF/MEK/ERK pathway, which induces the glycogen synthase kinase-3b-dependent activation ofthe transcription factor, cAMP response element-binding protein, which is responsible for PKG-Iboverexpressionin H-ras2/2mouse embryonic fibroblasts. This study demonstrates that H-rasdeletion protects against AngII-induced cardiac remodeling, possiblyviaa mechanism in which PKG-Iboverexpression could play a partial role, andpoints to H-Ras and/or downstream proteins as potential therapeutic targets in cardiovascular disease.Instituto de Salud Carlos IIIUniversidad de AlcaláFundación SenefroFEDE

Experimental and DFT characterization, antioxidant and anticancer activities of a Cu(II)–irbesartan complex: structure–antihypertensive activity relationships in Cu(II)–sartan complexes

The coordination compound of the antihypertensive ligand irbesartan (irb) with copper(II) (CuIrb) was synthesized and characterized by FTIR, FT-Raman, UV–visible, reflectance and EPR spectroscopies. Experimental evidence allowed the implementation of structural and vibrational studies by theoretical calculations made in the light of the density functional theory (DFT). This compound was designed to induce structural modifications on the ligand. No antioxidant effects were displayed by both compounds, though CuIrb behaved as a weak 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenger (IC₅₀ = 425 μM). The measurements of the contractile capacity on human mesangial cell lines showed that CuIrb improved the antihypertensive effects of the parent medication. In vitro cell growth inhibition against prostate cancer cell lines (LNCaP and DU 145) was measured for CuIrb, irbesartan and copper(II). These cell lines have been selected since the angiotensin II type 1 (AT1) receptor (that was blocked by the angiotensin receptor blockers, ARB) has been identified in them. The complex exerted anticancer behavior (at 100 μM) improving the activity of the ligand. Flow cytometry determinations were used to determine late apoptotic mechanisms of cell death.Facultad de Ciencias ExactasCentro de Química Inorgánic