Academic literature on the topic 'Cell motilty'

Abstract The Bcr-Abl oncogene is present in 30–40% of adult patients with acute lymphoblastic leukemia (ALL). The Abl kinase inhibitor imatinib-based therapy has become standard for this subset ALL. Acquired resistance to imatinib occurs frequently and is associated with mutations in the tyrosine kinase domain (TKD) approximately in about 80% of patients. In contrast, TKD mutations are uncommon in primary imatinib resistance which appears to be multifactorial, although the underlying mechanisms have been incompletely elucidated. We have established a Ph+ cell line for the analysis of non-mutational resistance mechanisms of imatinib resistance: SupB15RT, a Bcr-Abl expressing lymphoblastic cell line derived from SupB15WT cell line by gradually increasing the exposure to imatinib. SupB15RT shows cross-resistance to the second generation Abl kinase inhibitors Nilotinib and Dasatinib. We have shown that several commonly implicated mechanisms of imatinib resistance do not play a role in conferring the imatinib resistance in SupB15RT cells. By comparative gene expression analysis of SupB15WT vs. SupB15RT cells using Affymetrix- Microarrays, we identified 29 differentially regulated genes. Autotaxin (ATX) is one of the most highly up-regulated genes in imatinib resistant SupB15RT cells, and suggested a contribution to imatinib resistance. ATX is an exo-enzyme (pyrophosphophatase/phosphodiesterase). It plays a role in tumor progression and migration as a tumor cell autocrine motilty factor in various solid tumor cell types. ATX is involved in the synthesis of the signaling molecule, lysophosphatidic acid (LPA) which promotes survival and motility. It was the aim of this study to determine whereas ATX plays a functional role for imatinib resistance in Ph+ ALL. Using RT-PCR we demonstrated that 2 isoforms of ATX are expressed in SupB15RT cells: ATXshort and ATXlong. ATXlong (863 aa) contains highly basic insertion in the catalytic domain (52 residues). We retroviraly transfected BaF3 cells with p185 and/or ATXshort or ATXlong to analyze its influence on growth, adhesion and migration in mouse cell model. In comparison to wild type BaF3 cells the proliferation of BaF3 cells expressing ATXshort is enhanced (1,5-fold), whereas ATXlong expressing BaF3 cells showed no difference in proliferation in comparison to Mock infected cells. The proliferation of p185 expressing BaF3 cells co-expressing ATXshort or ATXlong is not inhibited by the treatment with 1μM imatinib after 3 days in contrast to p185 expressing BaF3 cells. In adhesion experiments, BaF3 cells expressing ATXshort showed a higher attachment independent of p185 expression. We also performed migration experiments using transwell assays. These assays showed more migration with cells co-expressing p185 and ATXlong compared to p185 alone. This is in agreement with our results for SupB15RT vs. SupB15WT with a 3-fold migration increase of SupB15RT. Application of 10% fetal calf serum (FCS) in migration experiments resulted in a 1,5-fold higher migration of the ATXlong expressing BaF3 cells compared to culture without FCS. One explanation for this finding may be that FCS contains lysophosphatidic choline (LPC) which is converted to LPA by ATX. Although expression of both 2 isoforms of ATX is important for the increased proliferation, it seems that the 2 isoforms have different cellular functions in Ph+ lymphoblastic cells. ATXshort seems to enhance adhesion whereas ATXlong plays an important role in motility. Taken together our results indicate a role for ATX in TK- inhibitor resistant SupB15RT cells through LPA signaling via LPA receptors. The ratio between ATXshort and ATXlong probably is important for the intracellular signaling and has to be explored.

Abstract T cells engineered to express chimeric antigen receptor (CAR) targeting CD19 have shown promising clinical responses in patients with certain hematologic malignancies, however, it is desirable to be able to enrich cells with enhanced anti-tumor efficacy prior to infusion. We utilized a suite of high-throughput technologies with single-cell resolution, including Timelapse Imaging Microscopy In Nanowell Grids (TIMING) that integrates cytokine profiling to reveal that persistent motility of CD19- specific CAR T cells is correlated to desirable polyfunctionality (elimination of tumor cells and cytokine secretion), contributing to anti-tumor effects. We implemented a marker-free Boyden chamber-based method to enrich CAR+ T cells with persistent motility (motile cell). Integration of transcriptomic profiling, immune phenotyping and metabolism demonstrated that motile cells are more naïve-like with higher oxidative metabolism and spare respiratory capacity. Our result also revealed that the master metabolic regulator AMP kinase (AMPK) is required for CAR+ T cells with high motility. We used a xenograft leukemia mouse model (CD19+ NALM-6) and validated that the motile cells have enhanced persistence and superior anti-cancer effect in vivo compared to the parental un-sorted population. Collectively, our multi-dimensional results demonstrated that persistent motility is a selectable biomarker of expanded CAR+ T cell bioactivity.

Metastasis is the outcome of several selective sequential steps where one of the first and necessary steps is the progressive overgrowth or dominance of a small number of metastatic cells in a tumour. In spite of numerous experimental investigations concerning the growth advantage of metastatic cells, the mechanisms resulting in their dominance are still unknown. Metastatic cell overgrowth occurs even if doubling time of the metastatic subpopulation is shorter than that of all others subpopulations in a heterogeneous tumour. In order to examine the hypothesis that under conditions of competition of cell subpopulations for common substrata cell motility of the slow-growing subpopulation can result in its dominance in a heterogeneous tumour, a mathematical model of heterogeneous tumour growth is suggested. The model describes two cell subpopulations which can grow with different rates and transform into the resting state depending on the concentration of the substrate consumed by both subpopulations. The slow-growing subpopulation is assumed to be motile. In numerical simulations it is shown that this subpopulation is able to overgrow the other one. The dominance phenomenon (resulting from random cell motion) depends on the motility coefficient in a threshold manner: in a heterogeneous tumour the slow-dividing motile subpopulation is able to overgrow its non-motile counterparts if its motility coefficient exceeds a certain threshold value. Computations demonstrate independence of the motile cells overgrowth from the initial tumour composition.

Abstract T-cell therapy with specificity redirected through chimeric antigen receptors (CARs) has shown efficacy for the treatment of hematologic malignancies. Although treatment with CAR T cell can result in high response rates, the properties of the cells that comprise the cellular infusion product, associated with clinical benefit are incompletely understood. We utilized a suite of high-throughput single-cell assays including single-cell RNA-sequencing (scRNA-seq); confocal microscopy; and Timelapse Imaging Microscopy In Nanowell Grids (TIMING). TIMING profiling of a cohort of 16 patients showed that persistent motility of T cells in the presence of tumor cells was associated with both serial killing capacity and polyfunctionality. Confocal microscopy on these same T cells revealed that persistent motility is linearly correlated with both mitochondrial volume and lysosomal number. ScRNA-seq demonstrated that T cells from responders were enriched in pathways related to T-cell proliferative capacity; interferon responses; and a distinct cluster of pathways related to actin cytoskeleton and migration. We employed a marker-free sorting strategy for enriching T cells with persistent motility. RNA-seq on sorted motile T cells showed an enrichment of the core motility signature. These motile T cells also demonstrated superior in vivo anti-leukemia efficacy in comparison to unsorted T cells. Lastly, we also confirmed the association with increased persistent motility and killing of CAR T cells across diverse CARs. In aggregate, our data identified that independent of CAR design or biomanufacturing, persistent motility serves as a selectable cell-intrinsic biomarker, desired in the bioactivity of expanded CAR+ T cells.

We analyse a generic motility model, with the motility mechanism arising by contractile stress due to the interaction of myosin and actin. A hydrodynamic active polar gel theory is used to model the cytoplasm of a cell and is combined with a Helfrich-type model to account for membrane properties. The overall model allows consideration of the motility without the necessity for local adhesion. Besides a detailed numerical approach together with convergence studies for the highly nonlinear free boundary problem, we also compare the induced flow field of the motile cell with that of classical squirmer models and identify the motile cell as a puller or pusher, depending on the strength of the myosin–actin interactions.

Phytoplankton often encounter turbulence in their habitat. As most toxic phytoplankton species are motile, resolving the interplay of motility and turbulence has fundamental repercussions on our understanding of their own ecology and of the entire ecosystems they inhabit. The spatial distribution of motile phytoplankton cells exhibits patchiness at distances of decimeter to millimeter scales for numerous species with different motility strategies. The explanation of this general phenomenon remains challenging. Furthermore, hydrodynamic cell–cell interactions, which grow more relevant as the density in the patches increases, have been so far ignored. Here, we combine particle simulations and continuum theory to study the emergence of patchiness in motile microorganisms in three dimensions. By addressing the combined effects of motility, cell–cell interaction, and turbulent flow conditions, we uncover a general mechanism: The coupling of cell–cell interactions to the turbulent dynamics favors the formation of dense patches. Identification of the important length and time scales, independent from the motility mode, allows us to elucidate a general physical mechanism underpinning the emergence of patchiness. Our results shed light on the dynamical characteristics necessary for the formation of patchiness and complement current efforts to unravel planktonic ecological interactions.

Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding.

Cadherin-mediated cell–cell adhesion is dynamically modulated during epithelial–mesenchymal transition triggered by activation of receptor tyrosine kinases (RTK) in epithelial cells. Several cadherin-binding proteins have been identified that control cell–cell adhesion. However, the mechanisms by which intercellular adhesion and cell motility are coregulated are still unknown. Here, we delineate a hitherto uncharted cooperation between RTKs, RhoA GTPase, and p120 catenin in instructing a motile behavior to epithelial cells. We found that expression of an N-terminus–deleted p120 catenin in a variety of epithelial cell types, including primary keratinocytes, effectively competes for endogenous p120 at cadherin binding sites and abrogates EGF-stimulated cell motility as well as HGF-induced cell scattering. The deleted mutant also inhibits the PI3K-dependent RhoA activation ensuing receptor activation. Conversely, we also show that the ectopic expression of full-length p120 in epithelial cells promotes cytoskeletal changes, stimulates cell motility, and activates RhoA. Both motogenic response to p120 and RhoA activation require coactivation of signaling downstream of RTKs as they are suppressed by ablation of the Ras/PI3K pathway. These studies demonstrate that p120 catenin is a necessary target of RTKs in regulating cell motility and help define a novel pathway leading to RhoA activation, which may contribute to the early steps of metastatic invasion.