Plant defensin PvD1 modulates the membrane composition of breast tumour-derived exosomes

This journal is © The Royal Society of Chemistry 2019One of the most important causes of failure in tumour treatment is the development of resistance to therapy. Cancer cells can develop the ability to lose sensitivity to anti-neoplastic drugs during reciprocal crosstalk between cells and their interaction with the tumour microenvironment (TME). Cell-to-cell communication regulates a cascade of interdependent events essential for disease development and progression and can be mediated by several signalling pathways. Exosome-mediated communication is one of the pathways regulating these events. Tumour-derived exosomes (TDE) are believed to have the ability to modulate TMEs and participate in multidrug resistance mechanisms. In this work, we studied the effect of the natural defensin from common bean, PvD1, on the formation of exosomes by breast cancer MCF-7 cells, mainly the modulatory effect it has on the level of CD63 and CD9 tetraspanins. Moreover, we followed the interaction of PvD1 with biological and model membranes of selected composition, by biophysical and imaging techniques. Overall, the results show that PvD1 induces a dual effect on MCF-7 derived exosomes: the peptide attenuates the recruitment of CD63 and CD9 to exosomes intracellularly and binds to the mature exosomes in the extracellular environment. This work uncovers the exosomemediated anticancer action of PvD1, a potential nutraceutical agent.The authors thank Fundação para a Ciência e a Tecnologia (FCT I.P., Portugal) for funding – PTDC/BBB-BQB/1693/2014, and also acknowledge financial support from the Brazilian agencies CNPq, CAPES, and FAPERJ (E-26/203.090/2016; E-26/202.132/2015). Julia Skalska, Filipa D. Oliveira, Tiago N. Figueira and Diana Gaspar acknowledge FCT I.P. for fellowships PD/BD/114177/2016, PD/BD/135046/2017, SFRH/BD/5283/2013 and SFRH/BPD/109010/2015 respectively. Marie Skłodowska-Curie Research and Innovation Staff Exchange (RISE) is also acknowledged for funding: call H2020-MSCA-RISE-2014, Grant agreement 644167, 2015–2019.info:eu-repo/semantics/publishedVersio

CM363, a novel naphthoquinone derivative which acts as multikinase modulator and overcomes imatinib resistance in chronic myelogenous leukemia

Human Chronic Myelogenous Leukemia (CML) is a hematological stem cell disorder which is associated with activation of Bcr-Abl-Stat5 oncogenic pathway. Direct Bcr-Abl inhibitors are initially successful for the treatment of CML but over time many patients develop drug resistance. In the present study, the effects of CM363, a novel naphthoquinone (NPQ) derivative, were evaluated on human CML-derived K562 cells. CM363 revealed an effective cell growth inhibition (IC50 = 0.7 ± 0.5 μM) by inducing cancer cells to undergo cell cycle arrest and apoptosis. CM363 caused a dose- and time-dependent reduction of cells in G0/G1 and G2/M phases. This cell cycle arrest was associated with increased levels of cyclin E, pChk1 and pChk2 whereas CM363 downregulated cyclin B, cyclin D3, p27, pRB, Wee1, and BUBR1. CM363 increased the double-strand DNA break marker γH2AX. CM363 caused a timedependent increase of annexin V-positive cells, DNA fragmentation and increased number of apoptotic nuclei. CM363 triggered the mitochondrial apoptotic pathway as reflected by a release of cytochrome C from mitochondria and induction of the cleavage of caspase-3 and -9, and PARP. CM363 showed multikinase modulatory effects through an early increased JNK phosphorylation followed by inhibition of pY-Bcrl-Abl and pY-Stat5. CM363 worked synergistically with imatinib to inhibit cell viability and maintained its activity in imatinib-resistant cells. Finally, CM363 (10 mg/Kg) suppressed the growth of K562 xenograft tumors in athymic mice. In summary, CM363 is a novel multikinase modulator that offers advantages to circumvent imanitib resistance and might be therapeutically effective in Bcrl-Abl- Stat5 related malignancies.This research has been supported by the Spanish Ministry of Science and Innovation (SAF2009-13296) and MINECO (SAF2012-37344, SAF2014-53526R, and SAF2015-65113-C2-2-R) with the co-funding of European Regional Development Fund (ERDF). This Project has been also supported by Centro Atlántico del Medicamento S.A. (CEAMED; www.ceamedsa.com) and Alfredo Martín-Reyes Foundation (Arehucas)-Canary Islands Foundation for Cancer Research (FICIC).Peer Reviewe

Chemical-proteomics Identify Peroxiredoxin-1 as an Actionable Target in Triple-negative Breast Cancer

Triple-negative breast cancer (TNBC) is difficult to treat; therefore, the development of drugs directed against its oncogenic vulnerabilities is a desirable goal. Herein, we report the antitumor effects of CM728, a novel quinone-fused oxazepine, against this malignancy. CM728 potently inhibited TNBC cell viability and decreased the growth of MDA-MB-231-induced orthotopic tumors. Furthermore, CM728 exerted a strong synergistic antiproliferative effect with docetaxel in vitro and this combination was more effective than the individual treatments in vivo. Chemical proteomic approaches revealed that CM728 bound to peroxiredoxin-1 (Prdx1), thereby inducing its oxidation. Molecular docking corroborated these findings. CM728 induced oxidative stress and a multi-signal response, including JNK/p38 MAPK activation and STAT3 inhibition. Interestingly, Prdx1 downregulation mimicked these effects. Finally, CM728 led to DNA damage, cell cycle blockage at the S and G2/M phases, and the activation of caspase-dependent apoptosis. Taken together, our results identify a novel compound with antitumoral properties against TNBC. In addition, we describe the mechanism of action of this drug and provide a rationale for the use of Prdx1 inhibitors, such as CM728, alone or in combination with other drugs, for the treatment of TNBC.This project was supported by Centro Atlántico del Medicamento S.A. (CEAMED), CDTI [IDI-20111517], ACIISI [EATIC2017010006], Universidad de Las Palmas de Gran Canaria, Cabildo Insular de Gran Canaria, Fundación del Instituto Canario de Investigación del Cáncer (FICIC), and Miguel Ángel Rodríguez Cardenes. E. Spínola-Lasso is the recipient of a predoctoral fellowship from the Agencia Canaria de Investigación, Innovación y Sociedad de la Información de la Consejería de Economía, Conocimiento y Empleo y por el Fondo Social Europeo (FSE) Programa Operativo Integrado de Canarias 2014-2020, Eje 3 Tema Prioritario 74 (85%) [TESIS2020010081]. J.C. Montero was funded by the Instituto de Salud Carlos III through the Miguel Servet Program [CP12/03073 and CPII17/00015] and received research support from the same institution [PI15/00684 and PI18/00796]. A. Pandiella received funding from the Ministry of Economy and Competitiveness of Spain [BFU2015-71371-R and PID2020-115605RB-I00], Instituto de Salud Carlos III through CIBERONC, Junta de Castilla y León [CSI146P20], CRIS Cancer Foundation, ACMUMA, UCCTA, ALMOM, and the European Community through the Regional Development Funding Program (FEDER)

JKST6, a novel multikinase modulator of the BCR-ABL1/STAT5 signaling pathway that potentiates direct BCR-ABL1 inhibition and overcomes imatinib resistance in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a hematological malignancy that highly depends on the BCR-ABL1/STAT5 signaling pathway for cell survival. First-line treatments for CML consist of tyrosine kinase inhibitors that efficiently target BCR-ABL1 activity. However, drug resistance and intolerance are still therapeutic limitations in Ph+ cells. Therefore, the development of new anti-CML drugs that exhibit alternative mechanisms to overcome these limitations is a desirable goal. In this work, the antitumoral activity of JKST6, a naphthoquinone-pyrone hybrid, was assessed in imatinib-sensitive and imatinib-resistant human CML cells. Live-cell imaging analysis revealed JKST6 potent antiproliferative activity in 2D and 3D CML cultures. JKST6 provoked cell increase in the subG1 phase along with a reduction in the G0/G1 phase and altered the expression of key proteins involved in the control of mitosis and DNA damage. Rapid increases in Annexin V staining and activation/cleavage of caspases 8, 9 and 3 were observed after JKST6 treatment in CML cells. Of interest, JKST6 inhibited BCR-ABL1/STAT5 signaling through oncokinase downregulation that was preceded by rapid polyubiquitination. In addition, JKST6 caused a transient increase in JNK and AKT phosphorylation, whereas the phosphorylation of P38-MAPK and Src was reduced. Combinatory treatment unveiled synergistic effects between imatinib and JKST6. Notably, JKST6 maintained its antitumor efficacy in BCR-ABL1-T315I-positive cells and CML cells that overexpress BCR-ABL and even restored imatinib efficacy after a short exposure time. These findings, together with the observed low toxicity of JKST6, reveal a novel multikinase modulator that might overcome the limitations of BCR-ABL1 inhibitors in CML therapy.This research has been funded by Spanish Ministry of Economy and Competitiveness - MINECO - (SAF 2015–65113-C2–1-R and RTI2018–094356-B-C21 to AEB, SAF2015–65113-C2–2 to LFP, SAF2017–88026-R to JL) with the co-funding of European Regional Development Fund (EU-ERDF), Canary Islands Government (CEI2018–23/ACIISI to BG, CEI2019–08/ACIISI to BG and LFP, ProID2021010037 to AEB, LFP and BG) and "Juan de la Cierva Incorporacion" Grant Program from the Ministry of Science, Innovation and Universities (IJC2018-035193-I to CR). This project has been also supported by Alfredo Martin-Reyes Foundation (Arehucas)-Canary Islands Foundation for Cancer Research (FICIC). HAT is recipient of a predoctoral program grant from ULPGC (2016). JCM was funded by the Instituto de Salud Carlos III through a Miguel Servet program (CPII17/ 00015)

Seasonal variation in the relative dominance of herbivore guilds in an African savanna

African savannas are highly seasonal with a diverse array of both mammalian and invertebrate herbivores, yet herbivory studies have focused almost exclusively on mammals. We conducted a 2-yr exclosure experiment in South Africa's Kruger National Park to measure the relative impact of these two groups of herbivores on grass removal at both highly productive patches (termite mounds) and in the less productive savanna matrix. Invertebrate and mammalian herbivory was greater on termite mounds, but the relative importance of each group changed over time. Mammalian offtake was higher than invertebrates in the dry season, but can be eclipsed by invertebrates during the wet season when this group is more active. Our results demonstrate that invertebrates play a substantial role in savanna herbivory and should not be disregarded in attempts to understand the impacts of herbivory on ecosystems

ISSN exercise & sport nutrition review: research & recommendations

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients

Barriers and facilitators to use of high technology augmentative and alternative communication devices: a systematic review and qualitative synthesis

Background: There has been a rapid growth in recent years of available technologies for individuals with communication difficulties. Research in the area is currently under-developed with practitioners having a limited body of work to draw on to guide the process of intervention. Concerns have been raised that this newly-developed technology may have limited functional usage. Aims: This review aimed to investigate the potential barriers and facilitators to high tech AAC provision and its ongoing use. The aim of the analysis was to explore factors underpinning use rather than effectiveness, thus it synthesised data from predominantly qualitative and survey studies reporting the views and perceptions of AAC users or staff providing the devices. Main Contribution: The review highlights the range of factors that can impact on provision and use of high tech AAC, which practitioners should consider and address as appropriate in the intervention process. These include: ease of use of the device; reliability; availability of technical support; the voice/language of the device; the decision-making process; the time taken to generate a message; family perceptions and support; communication partner responses; service provision; and the knowledge and skills of staff. The work outlines how qualitative synthesis review methods may be applied to the consideration of published material that is not reporting outcomes data, and how this may provide valuable information to inform future studies. Conclusions: Practitioners should be aware of barriers and facilitators to successful use when making recommendations, and consider how barriers where present, might be overcome. Aspects of service delivery such as ongoing technical support and staff training may require further consideration. The synthesis of evidence describing views of users and providers, and the implementation of high tech AAC systems, can provide valuable data to inform intervention studies and functional outcome measures