460 research outputs found
Rac1 plays a role in CXCL12 but not CCL3-induced chemotaxis and Rac1 GEF inhibitor NSC23766 has off target effects on CXCR4
Cell migration towards a chemotactic stimulus relies on the re-arrangement of the cytoskeleton, which is triggered by activation of small G proteins RhoA, Rac1 and Cdc42, and leads to formation of lamellopodia and actin polymerisation amongst other effects. Here we show that Rac1 is important for CXCR4 induced chemotaxis but not for CCR1/CCR5 induced chemotaxis. For CXCL12-induced migration via CXCR4, breast cancer MCF-7 cells are reliant on Rac1, similarly to THP-1 monocytes and Jurkat T-cells. For CCL3-induced migration via CCR1 and/or CCR5, Rac1 signalling does not regulate cell migration in either suspension or adherent cells. We have confirmed the involvement of Rac1 with the use of a specific Rac1 blocking peptide. We also used a Rac1 inhibitor EHT 1864 and a Rac1-GEF inhibitor NSC23766 to probe the importance of Rac1 in chemotaxis. Both inhibitors did not block CCL3-induced chemotaxis, but they were able to block CXCL12-induced chemotaxis. This confirms that Rac1 activation is not essential for CCL3-induced migration, however NSC23766 might have secondary effects on CXCR4. This small molecule exhibits agonistic features in internalisation and cAMP assays, whereas it acts as an antagonist for CXCR4 in migration and calcium release assays. Our findings strongly suggest that Rac1 activation is not necessary for CCL3 signalling, and reveal that NSC23766 could be a novel CXCR4 receptor ligand
Depth of Encoding Through Observed Gestures in Foreign Language Word Learning
Word learning is basic to foreign language acquisition, however time consuming and not always successful. Empirical studies have shown that traditional (visual) word learning can be enhanced by gestures. The gesture benefit has been attributed to depth of encoding. Gestures can lead to depth of encoding because they trigger semantic processing and sensorimotor enrichment of the novel word. However, the neural underpinning of depth of encoding is still unclear. Here, we combined an fMRI and a behavioral study to investigate word encoding online. In the scanner, participants encoded 30 novel words of an artificial language created for experimental purposes and their translation into the subjects\u2019 native language. Participants encoded the words three times: visually, audiovisually, and by additionally observing semantically related gestures performed by an actress. Hemodynamic activity during word encoding revealed the recruitment of cortical areas involved in stimulus processing. In this study, depth of encoding can be spelt out in terms of sensorimotor brain networks that grow larger the more sensory modalities are linked to the novel word. Word retention outside the scanner documented a positive effect of gestures in a free recall test in the short term
Seasonal Differences in the Attenuation of Polar Trace Organics in the Hyporheic Zone of an Urban Stream
Attenuation of trace organic compounds (TrOCs) in a river occurs to a large extent in its hyporheic zone. A major part of the attenuation of polar TrOCs is of microbial origin. As microbial activity depends on temperature and redox conditions, seasonal differences in TrOC attenuation are likely. We investigated TrOC attenuation at a river influenced by treated wastewater during two sampling campaigns, one in summer and one in winter. In addition to redox conditions and temperature, we also determined residence times of porewater in sediment using three methods: (a) non‐parametric deconvolution of electrical conductivity time series, (b) the model VFLUX 2.0 based on temperature time series (only summer), and (c) applying Darcy's law to differences in hydraulic heads (only summer). Contrary to our expectations, we found higher attenuation for 12 out of 18 TrOCs in winter, while three TrOCs were better attenuated in summer. Sediment conditions varied between seasons as more of the top sandy layer with a higher hydraulic permeability accumulated on the river bed in summer. As a result, residence times in the sediment were shorter in summer. In winter, longer residence times, lower temperatures, and a steeper oxygen gradient in sediment coincided with higher TrOC attenuation. Further research is needed to understand our unexpected findings and underlying mechanisms.Key Points
The attenuation of 12 out of 18 trace organic compounds (TrOCs) in the hyporheic zone was higher in winter while three TrOCs were attenuated better in summer
Residence times in sediment were longer and more diverse in winter
The extent of the oxic sediment was similar between seasons but the gradient from the oxic to anoxic zone was steeper in winterDeutsche Forschungsgemeinschaft (DFG)
http://dx.doi.org/10.13039/501100001659EC | H2020 | H2020 Priority Excellent Science | H2020 Marie Skłodowska‐Curie Actions (MSCA)
http://dx.doi.org/10.13039/100010665University of Western Australia ‐ University Postgraduate AwardAustralian Government Research Training Program ScholarshipBundesministerium für Bildung und Forschung (BMBF)
http://dx.doi.org/10.13039/501100002347Peer Reviewe
The role of PKC in CXCL8 and CXCL10 directed prostate, breast and leukemic cancer cell migration
Migration of tumour cells is a fundamental process for the formation and progression of metastasis in malignant diseases. Chemokines binding to their cognate receptors induce the migration of cancer cells, however, the molecular signalling pathways involved in this process are not fully understood. Protein kinase C (PKC) has been shown to regulate cell migration, adhesion and proliferation. In order to identify a connection between PKC and tumour progression in breast, prostate and leukaemia cells, the effect of PKC on CXCL8 or CXCL10-mediated cell migration and morphology was analysed. We tested the speed of the migrating cells, morphology, and chemotaxis incubated with different PKC isoforms inhibitors- GF109203X, staurosporine and PKCζ pseudosubstrate inhibitor (PKCζi). We found that the migration of CXCL8-driven PC3 and MDA-MB231 cells in the presence of conventional, novel or atypical PKCs was not affected, but atypical PKCζ is crucial for THP-1 chemotaxis. The speed of CXCL10-activated PC3 and MDA-MB231 cells was significantly reduced in the presence of conventional, novel and atypical PKCζ. THP-1 chemotaxis was again affected by atypical PKCζi. On the other hand, cell area, circularity or aspect ratio were affected by staurosporine in CXCL8 or CXCL10-activated cells, demonstrating a role of PKCα in the rearrangement of the cytoskeleton regardless of the effect on the migration. Consequently, this allows the speculation that different PKC isoforms induce different outcomes in migration and actin cytoskeleton based on the chemokine receptor and/or the cell type
Latest update on chemokine receptors as therapeutic targets
The chemokine system plays a fundamental role in a diverse range of physiological processes, such as homeostasis and immune responses. Dysregulation in the chemokine system has been linked to inflammatory diseases and cancer, which renders chemokine receptors to be considered as therapeutic targets. In the past two decades, around 45 drugs targeting chemokine receptors have been developed, yet only three are clinically approved. The challenging factors include the limited understanding of aberrant chemokine signalling in malignant diseases, high redundancy of the chemokine system, differences between cell types and non-specific binding of the chemokine receptor antagonists due to the broad ligand-binding pockets. In recent years, emerging studies attempt to characterise the chemokine ligand–receptor interactions and the downstream signalling protein–protein interactions, aiming to fine tuning to the promiscuous interplay of the chemokine system for the development of precision medicine. This review will outline the updates on the mechanistic insights in the chemokine system and propose some potential strategies in the future development of targeted therap
Diffuse swelling of the buccal mucosa and palate as first and only manifestation of an extranodal non-Hodgkin ‘double-hit' lymphoma: report of a case
Background: Most of the lymphomas arising in the oral cavity are of B-cell origin. Among these, diffuse large B-cell lymphomas are the most common. Diffuse large B-cell lymphomas may exhibit more than one chromosomal rearrangement and are then referred to as ‘double-hit' or ‘triple-hit' lymphomas. Case report: We present a case of an intraoral ‘double-hit' lymphoma in a 76-year-old male who had been referred by an oral surgeon in private practice. Intraoral examination exhibited a firm, exophytic lesion in the region of the right hard palate and buccal mucosa with extension to the soft palate. Radiographic examination exhibited a massive thickening of the right sinus membrane, and arrosion of the lateral and basal cortical sinus walls in the right maxilla. After diagnosis of the lesion, the patient was treated with six cycles of chemotherapy. Discussion: Lymphomas arising within the oral cavity account for less than 5% of all oral malignancies and typically affect the palatine tonsils and the palate. ‘Double-hit' lymphomas are associated with older age, usually present with an advanced stage of disease, and show an aggressive clinical behaviour. They normally have a poor prognosis, even when treated with intensive chemotherapy regimens. Nevertheless, in the case presented, the patient was free of symptoms 1year after initial diagnosi
An Integrated Interdisciplinary Faculty-Student Learning Community Focused on Water Issues: A Case Study
In response to a request from a campus student organization, faculty from three fields came together to develop and teach an integrated interdisciplinary course on water issues and social activism. This course, Water as Life, Death, and Power, brought together topics from the fields of anthropology, biology and chemistry to explore water rights, access to clean water, and water treatment methods. Students enrolled in the course developed projects related to a variety of local and global water issues to present real-world solutions at a university-wide student research showcase. This article describes how we organized the learning community, composed of students, faculty, and staff, and outlines the training process of developing a sense of community, content integration, and interdisciplinary teaching techniques.
Cathy Willermet is a Professor of Anthropology at Central Michigan University.
Eron Drake is the Assistant Director of the Faculty Center for Innovative Teaching at Central Michigan University.
Anja Mueller is a Professor of Chemistry at Central Michigan University.
Stephen J. Juris is a Professor of Biology at Central Michigan University.
Pratik Chhetri is a graduate student and a member of Universities Allied for Essential Medicines (UAEM) at Central Michigan University.
Samik Upadhaya is a graduate student and a member of UAEM at Central Michigan University
METHOD EVALUATION TO DETERMINE HYDRATION STATES OF TENDONS BY USING MRI
Due to the fact that water content is a determinant of the material properties of tendons and therefore might affect sports performance and the risk of injury, the purpose of this pilot study was to evaluate the reliabilityand sensitivity of a MRI based method to quantify content of a tendon. For this pilot study twenty porcine digital flexor tendons were chosen. All samples were examined on a MR scanner using three 3D ultra-short echo time sequences. With the applied sequences it was possible to determine a decrease in water content of the tendons. In addition, the methods showed a good inter session reliability. Further investigations are needed to improve the upper and lower limit of resolution regarding the physiological hydration state
Accuracy of Sentinel Lymph Node Mapping After Previous Hysterectomy in Patients with Occult Cervical Cancer.
BACKGROUND
In patients with a diagnosis of occult cervical cancer made on a hysterectomy specimen after surgery for a benign indication, lymph node assessment is crucial to determine treatment. We aimed to compare sentinel lymph node (SLN) mapping between patients with postoperative diagnosis of occult cervical carcinoma and patients with cervical cancer and uterus in situ.
METHODS
A retrospective analysis of cervical cancer patients International Federation of Gynecology and Obstetrics (FIGO) stage IA-IIA disease undergoing laparoscopic SLN mapping was performed. Patients were divided into two groups: those with a diagnosis of occult cervical cancer made on a hysterectomy specimen (group 1) and those with a diagnosis of cervical cancer and uterus in situ (group 2). Tracers used for SLN mapping included technetium-99m ((99m)Tc), blue dye, and indocyanine green. After detection and excision, the SLN was sent for frozen section analysis, and the planned surgical procedure was aborted in case of metastatic disease in favor of a chemoradiotherapeutic treatment.
RESULTS
Groups 1 and 2 included 9 and 62 patients, respectively. Clinicopathologic characteristics were similar among the two groups. Overall and bilateral detection rates were 66.6 and 33.3 and 95.1 and 87 % in groups 1 and 2, respectively (p < 0.05). No false-negative SLNs were identified in either group, with a negative predictive value of 100 %.
CONCLUSIONS
SLN mapping in occult cervical cancer patients has lower detection rates compared to patients with uterus in situ. In these patients, proper management of their disease has already failed before diagnosis, and additional mistakes may definitely compromise attempts at cure
Cell migration towards CXCL12 in leukemic cells compared to breast cancer cells
Chemotaxis or directed cell migration is mediated by signalling events initiated by binding of chemokines to their cognate receptors and the activation of a complex signalling cascade. The molecular signalling pathways involved in cell migration are important to understand cancer cell metastasis. Therefore we investigated the molecular mechanisms of CXCL12 induced cell migration and the importance of different signalling cascades that become activated by CXCR4 in leukemic cells versus breast cancer cells. We identified Src kinase as being essential for cell migration in both cancer types, with strong involvement of the Raf/MEK/ERK1/2 pathway. We did not detect any involvement of Ras or JAK2/STAT3 in CXCL12 induced migration in Jurkat cells. Preventing PKC activation with inhibitors does not affect migration in Jurkat cells at all, unlike in the adherent breast cancer cell line MCF-7 cells. However in both cell lines, knock down of PKCα prevents migration towards CXCL12, whereas the expression of PKCζ is less crucial for migration. PI3K activation is essential in both cell types, however LY294002 usage in MCF-7 cells does not block migration significantly. These results highlight the importance of verifying specific signalling pathways in different cell settings and with different approaches
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