A Photocaged Microtubule-Stabilising Epothilone Allows Spatiotemporal Control of Cytoskeletal Dynamics.

The cytoskeleton is essential for spatial and temporal organisation of a wide range of cellular and tissue-level processes, such as proliferation, signalling, cargo transport, migration, morphogenesis, and neuronal development. Cytoskeleton research aims to study these processes by imaging, or by locally manipulating, the dynamics and organisation of cytoskeletal proteins with high spatiotemporal resolution: which matches the capabilities of optical methods. To date, no photoresponsive microtubule-stabilising tool has united all the features needed for a practical high-precision reagent: a low potency and biochemically stable non-illuminated state; then an efficient, rapid, and clean photoresponse that generates a high potency illuminated state; plus good solubility at suitable working concentrations; and efficient synthetic access. We now present CouEpo, a photocaged epothilone microtubule-stabilising reagent that combines these needs. Its potency increases approximately 100-fold upon violet/blue irradiation to reach low-nanomolar values, allowing efficient photocontrol of microtubule dynamics in live cells, and even the generation of cellular asymmetries in microtubule architecture and cell dynamics. CouEpo is thus a high-performance tool compound that can support high-precision research into many microtubule-associated processes, from biophysics to transport, cell motility, and neuronal physiology.

Challenging gestational trophoblastic disease cases and mimics: An exemplar for the management of rare tumours.

OBJECTIVE: Rare tumour management is challenging for clinicians as evidence bases are limited and clinical trials are difficult to conduct. It is even more difficult for patients where self-reliance alone is insufficient to overcome the challenges of navigating care which is often poorly evidence based. In Ireland, a national Gestational Trophoblastic Disease (GTD) service was established as one of 3 initiatives for rare tumours by the National Cancer Control Programme. The service has a national clinical lead, a dedicated supportive nursing service and a clinical biochemistry liaison team. This study sought to assess the impact of a GTD centre using national clinical guidelines and integrating and networking with European and International GTD groups on the clinical management of challenging GTD cases and to consider the application of this model of care to other rare tumour management. STUDY DESIGN: In this article, we analyse the impact of a national GTD service on five challenging cases, and review how the service affects patient management in this rare tumour type. These cases were selected from a cohort of patients who were voluntarily registered in the service based on the diagnostic management dilemma they posed. RESULTS: Case management was impacted by the identification of GTD mimics, the provision of lifesaving treatment of metastatic choriocarcinoma with brain metastasis, networking with international colleagues, the identification of early relapse, the use of genetics to differentiate treatment pathways and prognosis, and supportive supervision of treatment courses of up to 2 years of therapy in a cohort of patients starting or completing families. CONCLUSION: The National GTD service could be an exemplar for the management of rare tumours (such as cholangiocarcinoma) in our jurisdiction which could benefit from a similar constellation of supports. Our study demonstrates the importance of a nominated national clinical lead, dedicated nurse navigator support, registration of cases and networking. The impact of our service would be greater if registration was mandatory rather than voluntary. Such a measure would also ensure equity of access for patients to the service, assist in quantifying the need for resourcing and facilitate research to improve outcomes.

[5]-Helistatins: Tubulin-Binding Helicenes with Antimitotic Activity.

Helicenes are high interest synthetic targets with unique conjugated helical structures that have found important technological applications. Despite this interest, helicenes have had limited impact in chemical biology. Herein, we disclose a first-in-class antimitotic helicene, helistatin 1 (HA-1), where the helicene scaffold acts as a structural mimic of colchicine, a known antimitotic drug. The synthesis proceeds via sequential Pd-catalyzed coupling reactions and a π-Lewis acid cycloisomerization mediated by PtCl2. HA-1 was found to block microtubule polymerization in both cell-free and live cell assays. Not only does this demonstrate the feasibility of using helicenes as bioactive scaffolds against protein targets, but also suggests wider potential for the use of helicenes as isosteres of biaryls or cis-stilbenes-themselves common drug and natural product scaffolds. Overall, this study further supports future opportunities for helicenes for a range of chemical biological applications.

Opto-katanin, an optogenetic tool for localized, microtubule disassembly.

Microtubules are cytoskeletal polymers that separate chromosomes during mitosis and serve as rails for intracellular transport and organelle positioning. Manipulation of microtubules is widely used in cell and developmental biology, but tools for precise subcellular spatiotemporal control of microtubules are currently lacking. Here, we describe a light-activated system for localized recruitment of the microtubule-severing enzyme katanin. This system, named opto-katanin, uses targeted illumination with blue light to induce rapid, localized, and reversible microtubule depolymerization. This tool allows precise clearing of a subcellular region of microtubules while preserving the rest of the microtubule network, demonstrating that regulation of katanin recruitment to microtubules is sufficient to control its severing activity. The tool is not toxic in the absence of blue light and can be used to disassemble both dynamic and stable microtubules in primary neurons as well as in dividing cells. We show that opto-katanin can be used to locally block vesicle transport and to clarify the dependence of organelle morphology and dynamics on microtubules. Specifically, our data indicate that microtubules are not required for the maintenance of the Golgi stacks or the tubules of the endoplasmic reticulum but are needed for the formation of new membrane tubules. Finally, we demonstrate that this tool can be applied to study the contribution of microtubules to cell mechanics by showing that microtubule bundles can exert forces constricting the nucleus.

Experience of women on the Irish National Gestational Trophoblastic Disease Registry.

OBJECTIVE: Gestational Trophoblastic Disease (GTD) is a rare pregnancy related disorder and the most curable of all gynaecological malignancies. GTD comprises the premalignant conditions of complete or partial hydatidiform mole known as molar pregnancy and a spectrum of malignant disorders termed gestational trophoblastic neoplasia. Clinical management and treatment in specialist centres is essential to achieve high cure rates and clinical guidelines recommend registration with a GTD centre as a minimum standard of care. National GTD registries are valuable repositories of epidemiological data and facilitate clinical audit, centralised pathology review and human chorionic gonadotropin (hCG) monitoring. This study sought the opinion of women enrolled on the Irish National GTD registry to inform future service development and establish a knowledge base for molar pregnancy in Ireland. STUDY DESIGN: A cross-sectional survey using an anonymised questionnaire was distributed by post to all women on the GTD registry. The questionnaire was designed by a multidisciplinary team and consisted of twenty-five closed-ended questions and two open-ended questions to facilitate feedback. Data collected in the survey included information on the patient experience of registration, knowledge of molar pregnancy, diagnosis at their local hospital, hCG monitoring and overall satisfaction with the service. RESULTS: The survey had a successful participation rate of 42.6% (215/504). Forty-nine percent (n = 106) of respondents rated a rapid hCG result as their top priority. Forty percent (n = 84) of women had concerns about future pregnancies but acknowledged that these were largely addressed by the GTD specialist nurses. A quarter of respondents reported that other medical professionals with whom they interacted during follow-up treatment did not understand their condition. Many women commented on the emotional stress of attending their local maternity unit for phlebotomy while dealing with pregnancy loss. CONCLUSION: This study is unique in being the first survey of women on the Irish National GTD registry. It highlights the specific needs of women with molar pregnancy in terms of psychological support, bereavement counselling and peer support groups. It reveals a knowledge gap in molar pregnancy amongst healthcare professionals which should be considered in future planning of medical and nursing curricula.

Photocontrolling Microtubule Dynamics with Photoswitchable Chemical Reagents.

Microtubule dynamics can be inhibited with sub-second temporal resolution and cellular-scale spatial resolution, by using precise illuminations to optically pattern where and when photoswitchable microtubule-inhibiting chemical reagents exert their latent bioactivity. The recently available reagents (SBTub, PST, STEpo, AzTax, PHTub) now enable researchers to use light to reversibly modulate microtubule-dependent processes in eukaryotes, in 2D and 3D cell culture as well as in vivo, across a variety of model organisms: with applications in fields from cargo transport to cell migration, cell division, and embryonic development.Here we give an introduction to using these photoswitchable microtubule inhibitors in cells. We describe the theory of small molecule photoswitching, and the unique performance features, usage requirements, and limitations that photoswitchable chemical reagents have; then we summarize the major classes of photoswitchable microtubule inhibitors that are currently available, with the properties that suit them to different applications, and troubleshooting measures for avoiding common mistakes. We outline workflows to establish cellular assays where they are used to optically control microtubule dynamics in a temporally reversible fashion with spatial specificity down to a single selected cell within a field of view. The methods in this chapter also equip the reader to tackle advanced uses of photoswitchable chemical reagents, in 3D culture and in vivo.

In Vivo Photocontrol of Microtubule Dynamics and Integrity, Migration and Mitosis, by the Potent GFP-Imaging-Compatible Photoswitchable Reagents SBTubA4P and SBTub2M.

Photoswitchable reagents are powerful tools for high-precision studies in cell biology. When these reagents are globally administered yet locally photoactivated in two-dimensional (2D) cell cultures, they can exert micron- and millisecond-scale biological control. This gives them great potential for use in biologically more relevant three-dimensional (3D) models and in vivo, particularly for studying systems with inherent spatiotemporal complexity, such as the cytoskeleton. However, due to a combination of photoswitch isomerization under typical imaging conditions, metabolic liabilities, and insufficient water solubility at effective concentrations, the in vivo potential of photoswitchable reagents addressing cytosolic protein targets remains largely unrealized. Here, we optimized the potency and solubility of metabolically stable, druglike colchicinoid microtubule inhibitors based on the styrylbenzothiazole (SBT) scaffold that are nonresponsive to typical fluorescent protein imaging wavelengths and so enable multichannel imaging studies. We applied these reagents both to 3D organoids and tissue explants and to classic model organisms (zebrafish, clawed frog) in one- and two-protein imaging experiments, in which spatiotemporally localized illuminations allowed them to photocontrol microtubule dynamics, network architecture, and microtubule-dependent processes in vivo with cellular precision and second-level resolution. These nanomolar, in vivo capable photoswitchable reagents should open up new dimensions for high-precision cytoskeleton research in cargo transport, cell motility, cell division, and development. More broadly, their design can also inspire similarly capable optical reagents for a range of cytosolic protein targets, thus bringing in vivo photopharmacology one step closer to general realization.

Life-threatening infections during treatment for acute lymphoblastic leukemia on the Malaysia-Singapore 2003 and 2010 clinical trials: A risk prediction model.

AIM: Life-threatening infections significantly impact the care of children undergoing therapy for acute lymphoblastic leukemia (ALL) who are at risk of severe sepsis due to both host and treatment factors. Our aim was to develop a life-threatening infection risk prediction model that would allow remote rapid triage of patients to reduce time to first dose of antibiotics and sepsis-related mortality. METHODS: A retrospective analysis of 2068 fever episodes during ALL therapy was used for model building and subsequent internal validation. RESULTS: Three hundred and seventy-seven patients were treated for ALL in two institutions with comparable critical and supportive care resources. A total of 55 patients accounted for 71 admissions to the critical care unit for sepsis that led to eight septic deaths during a 16-year study period. A retrospective analysis of risk factors for sepsis enabled us to build a model focused on 13 variables that discriminated admissions requiring critical care well: area under the receiver operating characteristic curve of .82; 95% CI .76-.87, p<.001, and Brier score of .033. Significant univariate predictors included neutropenia, presence of symptoms of abdominal pain, diarrhea, fever during induction or steroid-based phases, and the lack of any localizing source of infection at time of presentation. CONCLUSION: We have developed a risk prediction model that can reliably identify ALL patients undergoing treatment who are at a higher risk of life-threatening sepsis. Clinical applicability can potentially be extended to low-middle income settings, and its utility should be further studied in real-world settings.

Photoswitchable Epothilone-Based Microtubule Stabilisers Allow GFP-Imaging-Compatible, Optical Control over the Microtubule Cytoskeleton.

Optical methods to modulate microtubule dynamics show promise for reaching the micron- and millisecond-scale resolution needed to decrypt the roles of the cytoskeleton in biology. However, optical microtubule stabilisers are under-developed. We introduce "STEpos" as GFP-orthogonal, light-responsive epothilone-based microtubule stabilisers. They use a novel styrylthiazole photoswitch in a design to modulate hydrogen-bonding and steric effects that control epothilone potency. STEpos photocontrol microtubule dynamics and cell division with micron- and second-scale spatiotemporal precision. They substantially improve potency, solubility, and ease-of-use compared to previous optical microtubule stabilisers, and the structure-photoswitching-activity relationship insights in this work will guide future optimisations. The STEpo reagents can contribute greatly to high-precision research in cytoskeleton biophysics, cargo transport, cell motility, cell division, development, and neuroscience.

Postoperative Rather Than Preoperative Neutropenia Is Associated With Early Catheter-related Bloodstream Infections in Newly Diagnosed Pediatric Cancer Patients.

BACKGROUND: The relationship of early catheter-related bloodstream infections (CRBSIs) with perioperative neutropenia and antibiotic prophylaxis is not well established. We sought to evaluate perioperative factors associated with early CRBSIs in newly diagnosed pediatric cancer patients, particularly hematologic indices and antibiotic use. METHODS: We retrospectively reviewed national registry records of newly diagnosed pediatric cancer patients with port-a-caths inserted using standardized perioperative protocols where only antibiotic use was not regulated. Thirty-day postoperative CRBSI incidence was correlated with preoperative factors using logistic regression and with postoperative blood counts using linear trend analysis. RESULTS: Among 243 patients, 17 CRBSIs (7.0%) occurred at median 14 (range, 8-28) postoperative days. Early CRBSIs were significantly associated with cancer type [acute myeloid leukemia and other leukemias (AML/OLs) vs. solid tumors and lymphomas (STLs): odds ratio (OR), 5.09; P = 0.0036; acute lymphoblastic leukemia vs. STL: OR 0.83; P = 0.0446] but not preoperative antibiotics, absolute neutrophil counts and white blood cell counts. Thirty-day postoperative absolute neutrophil counts and white blood cell trends differed significantly between patients with acute lymphoblastic leukemia and STLs (OR 0.83, P < 0.05) and between AML/OLs and STLs (OR 5.09, P < 0.005), with AML/OL patients having the most protracted neutropenia during this period. CONCLUSIONS: Contrary to common belief, low preoperative absolute neutrophil counts and lack of preoperative antibiotics were not associated with higher early CRBSI rates. Instead, AML/OL patients, particularly those with prolonged neutropenia during the first 30 postoperative days, were at increased risk. Our findings do not support the use of empirical preoperative antibiotics and instead identify prolonged postoperative neutropenia as a major contributing factor for early CRBSI.

Pyrrole Hemithioindigo Antimitotics with Near-Quantitative Bidirectional Photoswitching that Photocontrol Cellular Microtubule Dynamics with Single-Cell Precision*.

We report the first cellular application of the emerging near-quantitative photoswitch pyrrole hemithioindigo, by rationally designing photopharmaceutical PHTub inhibitors of the cytoskeletal protein tubulin. PHTubs allow simultaneous visible-light imaging and photoswitching in live cells, delivering cell-precise photomodulation of microtubule dynamics, and photocontrol over cell cycle progression and cell death. This is the first acute use of a hemithioindigo photopharmaceutical for high-spatiotemporal-resolution biological control in live cells. It additionally demonstrates the utility of near-quantitative photoswitches, by enabling a dark-active design to overcome residual background activity during cellular photopatterning. This work opens up new horizons for high-precision microtubule research using PHTubs and shows the cellular applicability of pyrrole hemithioindigo as a valuable scaffold for photocontrol of a range of other biological targets.

Gastrointestinal and oncologic outcomes of pediatric gastrointestinal lymphoma following upfront resection or biopsy of bowel masses.

PURPOSE: Complete upfront resection of pediatric gastrointestinal lymphomas is recommended over biopsy whenever feasible, but either approach may have adverse sequelae. We sought to compare gastrointestinal and oncological outcomes of pediatric gastrointestinal lymphomas who underwent attempted upfront resection or biopsy of the presenting bowel mass. METHODS: We retrospectively reviewed charts of children with gastrointestinal lymphomas treated on LMB89 and LMB96 protocols from 2000 to 2019 who underwent upfront gastrointestinal surgery, and compared resection and biopsy groups. RESULTS: Of 33 children with abdominal lymphomas, 20 had upfront gastrointestinal surgery-10 each had resection or biopsy. Patients with attempted upfront resections had fewer postoperative gastrointestinal complications compared to biopsies (10% vs. 60%, p = 0.057), but longer time to chemotherapy initiation (median 11.5 vs. 4.5 days, p < 0.001). Three resection patients were surgically down-staged. Second surgeries were required in 30% and 40% of resected and biopsied patients, respectively, at median 4.6 months. Survival was similar in both groups, but better in patients on LMB96 protocol and stage II/III disease. CONCLUSIONS: Children with upfront attempted resection had low rates of surgical down-staging, greater delay in chemotherapy initiation, but fewer gastrointestinal complications and subsequent surgeries than biopsies. Survival was similar regardless of upfront surgery, likely reflecting beneficial effects of newer protocols.

Successful toxicity reduction during delayed intensification in the non-high-risk arm of Malaysia-Singapore Acute Lymphoblastic Leukaemia 2010 study.

In non-high-risk (non-HR) patients, the Malaysia-Singapore Acute Lymphoblastic Leukaemia 2003 (MS2003) study achieved good outcomes. However, its delayed-intensification (DI) phase, comprising repeated blocks of protocol III (2003-PIII), was toxic and caused significant treatment delays. The successor MS2010 study attempted to lower DI toxicity by replacing myelosuppressive drugs (doxorubicin, cytarabine) with vincristine and asparaginase. PATIENTS AND METHODS: We analysed 1748 admissions for fever in 315 Singapore children with non-HR acute lymphoblastic leukaemia (ALL) (MS2003, n = 183; MS2010, n = 132), comprising 76% of the total cohort (n = 413), to study the impact of these changes. RESULTS: The new 2010-PVa which has no doxorubicin, was associated with significantly fewer hospitalisations due to fever (0.08 versus 0.30 admissions per block [A/blk], p < 0.001), as than 2003-PIIIa. Similarly in 2010-PIIIb and PVb, where one block of cytarabine was replaced by two doses of vincristine, admissions for fever were also fewer (0.47 versus 0.74 A/blk, p < 0.001) than in 2003-PIIIb. However, the addition of single doses of vincristine and asparaginase in 2010-PIIIa, even with a mandatory seven-day rest, led to more hospitalisations (0.45 A/blk, p < 0.001), increased risk of bacteraemia (relative-risk (RR) = 7.66, p = 0.005) and critical-care admissions (RR = 4.31, p = 0.13). Despite this, overall treatment-related mortality decreased from 2.7% to 0.8%. Taken together, the reduced phase delays allowed earlier completion of the intensive phase of treatment (standard risk: 38.1 versus 49.4 weeks, p < 0.001; intermediate risk: 50.9 versus 58.8 weeks, p < 0.001), while maintaining excellent 10-year event-free survival of 95.4% and overall survival of 96.2%. CONCLUSIONS: In non-HR ALL, replacing doxorubicin/cytarabine with vincristine/asparaginase during some DI blocks is effective in reducing toxicity without compromising outcomes. CLINICAL TRIAL INFORMATION: NCT0289464.

A Robust, GFP-Orthogonal Photoswitchable Inhibitor Scaffold Extends Optical Control over the Microtubule Cytoskeleton.

Optically controlled chemical reagents, termed "photopharmaceuticals," are powerful tools for precise spatiotemporal control of proteins particularly when genetic methods, such as knockouts or optogenetics are not viable options. However, current photopharmaceutical scaffolds, such as azobenzenes are intolerant of GFP/YFP imaging and are metabolically labile, posing severe limitations for biological use. We rationally designed a photoswitchable "SBT" scaffold to overcome these problems, then derivatized it to create exceptionally metabolically robust and fully GFP/YFP-orthogonal "SBTub" photopharmaceutical tubulin inhibitors. Lead compound SBTub3 allows temporally reversible, cell-precise, and even subcellularly precise photomodulation of microtubule dynamics, organization, and microtubule-dependent processes. By overcoming the previous limitations of microtubule photopharmaceuticals, SBTubs offer powerful applications in cell biology, and their robustness and druglikeness are favorable for intracellular biological control in in vivo applications. We furthermore expect that the robustness and imaging orthogonality of the SBT scaffold will inspire other derivatizations directed at extending the photocontrol of a range of other biological targets.

Safety and efficacy of anticoagulant therapy in pediatric catheter-related venous thrombosis (EINSTEIN-Jr CVC-VTE).

Anticoagulant treatment of pediatric central venous catheter-related venous thromboembolism (CVC-VTE) has not been specifically evaluated. In EINSTEIN-Jr, 500 children with any VTE received rivaroxaban or standard anticoagulants. A predefined analysis of the CVC-VTE cohort was performed. Children with CVC-VTE (age, birth to 17 years) were administered rivaroxaban or standard anticoagulants during the 1-month (children <2 years) or 3-month (all other children) study period. Predefined outcomes were recurrent VTE, change in thrombotic burden on repeat imaging, and bleeding. Predictors for continuation of anticoagulant therapy beyond the study period were evaluated. One hundred twenty-six children with symptomatic (n = 76, 60%) or asymptomatic (n = 50, 40%) CVC-VTE received either rivaroxaban (n = 90) or standard anticoagulants (n = 36). There was no recurrent VTE (0%; 95% confidence interval [CI], 0.0%-2.8%). Three children had the principal safety outcome: none had major bleeding and 3 children had clinically relevant nonmajor bleeding (2.4%; 95% CI, 0.7%-6.5%), all in the rivaroxaban arm. Complete or partial vein recanalization occurred in 57 (55%) and 38 (37%) of 103 evaluable children, respectively. Results were similar for symptomatic and asymptomatic CVC-VTE. Continuation of anticoagulant therapy beyond the study period occurred in 61 (48%) of children and was associated with residual VTE but only in children <2 years (odds ratio [OR], 20.9; P = .003) and continued CVC use (OR, 6.7; P = .002). Anticoagulant therapy appeared safe and efficacious and was associated with reduced clot burden in most children with symptomatic or asymptomatic CVC-VTE. Residual VTE and continued CVC use were associated with extended anticoagulation. This trial was registered at www.clinicaltrials.gov as #NCT02234843.

Photoswitchable paclitaxel-based microtubule stabilisers allow optical control over the microtubule cytoskeleton.

Small molecule inhibitors are prime reagents for studies in microtubule cytoskeleton research, being applicable across a range of biological models and not requiring genetic engineering. However, traditional chemical inhibitors cannot be experimentally applied with spatiotemporal precision suiting the length and time scales inherent to microtubule-dependent cellular processes. We have synthesised photoswitchable paclitaxel-based microtubule stabilisers, whose binding is induced by photoisomerisation to their metastable state. Photoisomerising these reagents in living cells allows optical control over microtubule network integrity and dynamics, cell division and survival, with biological response on the timescale of seconds and spatial precision to the level of individual cells within a population. In primary neurons, they enable regulation of microtubule dynamics resolved to subcellular regions within individual neurites. These azobenzene-based microtubule stabilisers thus enable non-invasive, spatiotemporally precise modulation of the microtubule cytoskeleton in living cells, and promise new possibilities for studying intracellular transport, cell motility, and neuronal physiology.

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response.

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient-derived cell cultures (PDCs) from chemo-naïve and post-treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo-response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal-type gene expression signature and showed upregulation of pro-angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard-of-care cytotoxics at human Cmax -equivalent concentrations, MYCN-amplified and non-MYCN-amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients' responses, and correlated with gene signatures of chemosensitivity. In this translational proof-of-concept study, early-phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug-response testing.

Microtubules keep large cells in shape.

Migrating cells need to coordinate extension and retraction of their protrusions to avoid fragmenting. Kopf et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.201907154) demonstrate that microtubules help to maintain cell coherence during amoeboid migration by controlling actomyosin contractility in retracting protrusions.