The plasticity of melanoma cell invasiveness

and keywords: During metastasis, cancer cells can invade the extracellular matrix using various strategies. When invading individually, they employ either the amoeboid invasion mode, during which the cell body dynamically deforms by enhanced contractility to squeeze through pores within the matrix, or protease dependent mesenchymal migration that takes advantage of the possibility to digest the surrounding matrix. Cells migrating in one mode can actively switch to the other by mesenchymal-amoeboid (MAT) or amoeboid-mesenchymal transitions (AMT). This enables escape mechanisms and considerably complicates anti-metastatic treatment. It is well known that Rho GTPases are master regulators of cytoskeleton re-arrangements and thus, unsurprisingly, play a major role in both invasion modes and can directly drive the transitions. However, upstream activation of these pathways is still largely unclear. This thesis aimed to optimize 3D conditions suitable for studying plasticity of cell invasion in vitro, establish AMT and MAT in melanoma cells based on manipulation of Rho GTPases and verify novel candidates regulating cell invasion plasticity based on previous RNA sequencing of cells before and after MAT. Last, by synthesis of published data, results from sequencing and new findings presented in this...a klíčová slova: Během metastazování mohou rakovinové buňky využívat různé strategie pro invazi skrz extracelulární matrix. Při individuální invazi využívají buď améboidní migrační mód, během kterého buňka dynamicky mění tvar díky zvýšené kontraktilitě tak, aby mohla prolézat póry v extracelulárním prostředí, nebo mesenchymální migraci, která je závislá na proteolytickém štěpení a využívá možnosti degradace okolní tkáně. Buňky migrující v daném módu mohou aktivně přecházet do druhého módu v procesu mesenchymálně-améboidního přechodu (MAT) nebo améboidně-mesenchymálního přechodu (AMT). To jim nabízí únikové cesty, což značně komplikuje léčbu metastatické rakoviny. Je známo, že Rho GTPázy jsou hlavními regulátory přestavby cytoskeletu a není tedy překvapením, že hrají důležitou roli v obou migračních modech a mohou přímo řídit přechody mezi nimi. Nicméně, aktivace těchto drah je stále poměrně nejasná. Tato práce si kladla za cíl optimalizovat 3D podmínky vhodné pro studium plasticity invazivních módů in vitro, poté na bázi manipulace s Rho GTPázami ustanovit modely pro studium AMT a MAT v melanomových buňkách a ověřit nové kandidáty regulující plasticitu buněčné invazivity dle předchozích dat získaných sekvenováním RNA z buněk před a po MAT. Nakonec, pomocí syntézy publikovaných dat, výsledků ze...Katedra buněčné biologieDepartment of Cell BiologyPřírodovědecká fakultaFaculty of Scienc

Úloha signalizace regulující buněčnou polaritu v plasticitě invazivity nádorových buněk

Výzkum rakoviny se v posledních letech zaměřil na vznik sekundárních nádorů, tj. metastáz, které jsou přímým důsledkem schopnosti nádorových buněk opustit primární nádor a invadovat do okolní tkáně. Rakovinové buňky migrují především dvěma rozdílnými mechanismy- améboidním a mezenchymálním. Zatímco mezenchymální způsob migrace lze popsat jako "cestu vytvářející", améboidní připomíná spíš "cestu hledající" migraci. Oba typy invazivity jsou regulovány odlišnými signálními dráhami, které úzce souvisí s buněčnou polaritou a přestavbou cytoskeletu. Za polaritu buňky jsou zodpovědné nejen polarizační komplexy Par, Scribble a Crumbs, ale také fosfoinositidy a Rho GTPázy Rac, Rho a Cdc42, které navíc řídí dynamiku cytoskeletu. Vzájemnou souhrou regulují buněčnou motilitu. Není proto překvapením, že jejich deregulace často vede ke karcinogenezi. Dokonalejší prozkoumání signálních drah vedoucích k buněčné invasivitě je nutným krokem k porozumění komplexního problému vzniku metastáz. Klíčová slova: invazivita, améboidní, mezenchymální, buněčná polarita, motilita, Rho GTPázy, polarizační komplexyThroughout the last few years cancer research has focused on studying the origin of secondary tumors, i.e. metastases, which are a direct outcome of the ability of cancer cells to disseminate from the primary tumor and invade the adjacent tissue. Generally, cancer cells migrate by two distinct mechanisms- amoeboid or mesenchymal. Whereas the mesenchymal migration mode can be described as "path generating", the amoeboid mode resembles a "path finding" way of migration. Both types of invasion are regulated by divergent signaling pathways that are closely related to cell polarity and cytoskeleton reorganization. Responsible for cell polarization are not only the polarity complexes Par, Scribble and Crumbs, but also phosphoinositides and Rho GTPases Rac, Rho and Cdc42, which, additionally, regulate the dynamics of the cytoskeleton. By a mutual interplay they regulate cell motility. It cannot come as a surprise that their deregulation commonly results in tumorigenesis. A more thorough comprehension of the signaling pathways leading to cancer cell invasiveness is a necessary step towards understanding the complex problem of metastasis. Key words: invasiveness, amoeboid, mesenchymal, cell polarity, motility, Rho GTPases, polarity complexesDepartment of Cell BiologyKatedra buněčné biologiePřírodovědecká fakultaFaculty of Scienc

How 'Fake News' Affects Autism Policy

Since autism was first recognised, prevalence has increased rapidly. The growing economic as well as social cost to families and society can only be mitigated by effective interventions and supports. It is, therefore, not surprising that there is much heated debate and most governments have developed public policies to address the management of autism. This paper describes how well-known ‘propaganda’ techniques, that have become prevalent in the helping professions have been used to influence autism policies by spreading ‘fake news’ about the scientific discipline of Applied Behaviour Analysis (ABA). Over the past 40–50 years, meaningful evidence has accrued showing that interventions based on ABA can help people with autism reach their potential. In view of this, nearly all of North America has laws to mandate that ABA-based interventions are available through their health care systems. In contrast, across Europe there are no such laws. In fact, the National Institute for Health and Care Excellence (NICE), the body guiding health and social policy in the UK, concluded that it could not find any evidence to support ABA, and therefore could not recommend it. This paper addresses the reasons for these diametrically opposed perspectives

Migrastatics—anti-Metastatic and Anti-invasion Drugs:Promises and Challenges

In solid cancers, invasion and metastasis account for more than 90% of mortality. However, in the current armory of anticancer therapies, a specific category of anti-invasion and antimetastatic drugs is missing. Here, we coin the term ‘migrastatics’ for drugs interfering with all modes of cancer cell invasion and metastasis, to distinguish this class from conventional cytostatic drugs, which are mainly directed against cell proliferation. We define actin polymerization and contractility as target mechanisms for migrastatics, and review candidate migrastatic drugs. Critical assessment of these antimetastatic agents is warranted, because they may define new options for the treatment of solid cancers

Migrastatics-Anti-metastatic and Anti-invasion Drugs: Promises and Challenges

In solid cancers, invasion and metastasis account for more than 90% of mortality. However, in the current armory of anticancer therapies, a specific category of anti-invasion and antimetastatic drugs is missing. Here, we coin the term ‘migrastatics’ for drugs interfering with all modes of cancer cell invasion and metastasis, to distinguish this class from conventional cytostatic drugs, which are mainly directed against cell proliferation. We define actin polymerization and contractility as target mechanisms for migrastatics, and review candidate migrastatic drugs. Critical assessment of these antimetastatic agents is warranted, because they may define new options for the treatment of solid cancers

CDC42EP5/BORG3 modulates SEPT9 to promote actomyosin function, migration, and invasion.

Fast amoeboid migration is critical for developmental processes and can be hijacked by cancer cells to enhance metastatic dissemination. This migratory behavior is tightly controlled by high levels of actomyosin contractility, but how it is coupled to other cytoskeletal components is poorly understood. Septins are increasingly recognized as novel cytoskeletal components, but details on their regulation and contribution to migration are lacking. Here, we show that the septin regulator Cdc42EP5 is consistently required for amoeboid melanoma cells to invade and migrate into collagen-rich matrices and locally invade and disseminate in vivo. Cdc42EP5 associates with actin structures, leading to increased actomyosin contractility and amoeboid migration. Cdc42EP5 affects these functions through SEPT9-dependent F-actin cross-linking, which enables the generation of F-actin bundles required for the sustained stabilization of highly contractile actomyosin structures. This study provides evidence that Cdc42EP5 is a regulator of cancer cell motility that coordinates actin and septin networks and describes a unique role for SEPT9 in melanoma invasion and metastasis

MASTL promotes cell contractility and motility through kinase-independent signaling

Microtubule-associated serine/threonine-protein kinase-like (MASTL) is a mitosis-accelerating kinase with emerging roles in cancer progression. However, possible cell cycle-independent mechanisms behind its oncogenicity remain ambiguous. Here, we identify MASTL as an activator of cell contractility and MRTF-A/SRF (myocardin-related transcription factor A/serum response factor) signaling. Depletion of MASTL increased cell spreading while reducing contractile actin stress fibers in normal and breast cancer cells and strongly impairing breast cancer cell motility and invasion. Transcriptome and proteome profiling revealed MASTL-regulated genes implicated in cell movement and actomyosin contraction, including Rho guanine nucleotide exchange factor 2 (GEF-H1, ARHGEF2) and MRTF-A target genes tropomyosin 4.2 (TPM4), vinculin (VCL), and nonmuscle myosin IIB (NM-2B, MYH10). Mechanistically, MASTL associated with MRTF-A and increased its nuclear retention and transcriptional activity. Importantly, MASTL kinase activity was not required for regulation of cell spreading or MRTF-A/SRF transcriptional activity. Taken together, we present a previously unknown kinase-independent role for MASTL as a regulator of cell adhesion, contractility, and MRTF-A/SRF activity. [Abstract copyright: © 2020 Taskinen et al.

Sepulchral Ironwork in Early Modern Bohemia. Ironwork and Sepulchral Environment between 1550-1740

The text deals with various types of ironwork from ca 1550-1740, which we can encounter in sepulchral spaces in Bohemia. The text includes notable examples of individual types of ironwork related to sepulchral monuments in Bohemia and even Central Europe, especially when the works were inspired by Bohemian examples. The main research subject matter of the dissertation is a typological group of ironwork that defined the space around a tombstone or mausoleum freely situated in a sacred environment, e.g. the most important cited work - the ironwork surrounding the Royal Mausoleum in Prague, or the ironwork surrounding the Cenotaph of Maxmilian I located in the Court Church of Innsbruck. Other types of ironwork related to sepulchral monuments are mentioned complementarily, such as ironwork closing off interior chapels, freely standing ironwork, and ironwork protecting sepulchral niches. Powered by TCPDF (www.tcpdf.org