Interaction of normal haemopoiesis and L5222 leukaemic cells in vivo and in vitro

It was demonstrated previously that mice undergoing an inflammatory reaction induced by subcutaneous (SC) implantation of copper rods, produce humoral factors that initially enhance, but subsequently inhibit, diffusion chamber (DC) granulopoiesis. This provided evidence that granulopoiesis is under the control of both humoral stimulators and inhibitors. In order to test the granulopoietic regulatory mechanism in leukaemic mice, we investigated the regulatory role of granulopoietic humoral inhibitors during in vivo granulopoiesis. We noticed that mice suffering from acute myeloid leukaemia (AML) are unable to augment the production of these humoral inhibitory factors when acute inflammation is induced, since no change in DC cell content was observed with or without prior inflammation. Moreover, unlike healthy mice, the serum of leukaemic mice withdrawn during the inhibition phase of acute inflammation did not show any inhibitory activity toward granulocyte—monocyte (GM) colony growth in vitro. Our results also show that increased levels of normal humoral inhibitors do not influence the proliferation and/or differentiation of leukaemic cells implanted in diffusion chamber cultures.

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EZN-2208 treatment suppresses chronic lymphocytic leukaemia by interfering with environmental protection and increases response to fludarabine

Open Biology ◽

10.1098/rsob.190262 ◽

2020 ◽

Vol 10 (5) ◽

pp. 190262

Author(s):

Roberta Valsecchi ◽

Nadia Coltella ◽

Daniela Magliulo ◽

Lucia Bongiovanni ◽

Lydia Scarfò ◽

...

Keyword(s):

Transcription Factor ◽

Chronic Lymphocytic Leukaemia ◽

Environmental Protection ◽

Lymphocytic Leukaemia ◽

Therapeutic Approaches ◽

Leukaemic Cells ◽

Induced Apoptosis ◽

Early Phases

The transcription factor HIF-1α is overexpressed in chronic lymphocytic leukaemia (CLL), where it promotes leukaemia progression by favouring the interaction of leukaemic cells with protective tissue microenvironments. Here, we tested the hypothesis that a pharmacological compound previously shown to inhibit HIF-1α may act as a chemosensitizer by interrupting protective microenvironmental interactions and exposing CLL cells to fludarabine-induced cytotoxicity. We found that the camptothecin-11 analogue EZN-2208 sensitizes CLL cells to fludarabine-induced apoptosis in cytoprotective in vitro cultures; in vivo EZN-2208 improves fludarabine responses, especially in early phases of leukaemia expansion, and exerts significant anti-leukaemia activity, thus suggesting that this or similar compounds may be considered as effective CLL therapeutic approaches.

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Assessment of the sensitivity of leukaemic cells to cytotoxic drugs by bioluminescence measurement of ATP in cultured cells

Clinical Science ◽

10.1042/cs0710081 ◽

1986 ◽

Vol 71 (1) ◽

pp. 81-88 ◽

Cited By ~ 18

Author(s):

Rudolf Kuzmits ◽

Paul Aiginger ◽

Matthias M. Müller ◽

Günter Steurer ◽

Werner Linkesch

Keyword(s):

Cultured Cells ◽

Dose Effect ◽

Blue Dye ◽

Response Patterns ◽

Cytostatic Agents ◽

Drug Induced ◽

Atp Assay ◽

Leukaemic Cells

1. A short-term test in vitro is described, which can be used to detect resistance to cytostatic agents in leukaemic cells. Leukaemic cell suspensions were incubated with cytostatic agents and the resulting intracellular ATP concentrations were measured by a bioluminescence ATP assay. 2. There was a clear dose-effect relationship in acute leukaemia and chronic lymphocytic leukaemia cells for drugs used in the treatment of leukaemias. A good correlation was found between the ATP content of leukaemic cells and cell viability as determined by the trypan blue dye exclusion test. 3. Preliminary individual clinical correlations suggest a correlation between the chemosensitivity in vitro and the response patterns in vivo in leukaemia patients. This simple, fast and sensitive method may have application for determination of drug-induced cytotoxicity in leukaemic cells in vitro.

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Abi-1-bridged tyrosine phosphorylation of VASP by Abelson kinase impairs association of VASP to focal adhesions and regulates leukaemic cell adhesion

Biochemical Journal ◽

10.1042/bj20110951 ◽

2012 ◽

Vol 441 (3) ◽

pp. 889-901 ◽

Cited By ~ 26

Author(s):

Masahiro Maruoka ◽

Mizuho Sato ◽

Yunfeng Yuan ◽

Masayoshi Ichiba ◽

Ryosuke Fujii ◽

...

Keyword(s):

Focal Adhesions ◽

K562 Cells ◽

Dependent Manner ◽

Wild Type ◽

Abelson Kinase ◽

Leukaemic Cells ◽

Phosphoinositide 3 Kinase ◽

Proline Rich Region

Mena [mammalian Ena (Enabled)]/VASP (vasodilator-stimulated phosphoprotein) proteins are the homologues of Drosophila Ena. In Drosophila, Ena is a substrate of the tyrosine kinase DAbl (Drosophila Abl). However, the link between Abl and the Mena/VASP family is not fully understood in mammals. We previously reported that Abi-1 (Abl interactor 1) promotes phosphorylation of Mena and BCAP (B-cell adaptor for phosphoinositide 3-kinase) by bridging the interaction between c-Abl and the substrate. In the present study we have identified VASP, another member of the Mena/VASP family, as an Abi-1-bridged substrate of Abl. VASP is phosphorylated by Abl when Abi-1 is co-expressed. We also found that VASP interacted with Abi-1 both in vitro and in vivo. VASP was tyrosine-phosphorylated in Bcr-Abl-positive leukaemic cells in an Abi-1-dependent manner. Co-expression of c-Abl and Abi-1 or the phosphomimetic Y39D mutation in VASP resulted in less accumulation of VASP at focal adhesions. VASP Y39D had a reduced affinity to the proline-rich region of zyxin. Interestingly, overexpression of both phosphomimetic and unphosphorylated forms of VASP, but not wild-type VASP, impaired adhesion of K562 cells to fibronectin. These results suggest that the phosphorylation and dephosphorylation cycle of VASP by the Abi-1-bridged mechanism regulates association of VASP with focal adhesions, which may regulate adhesion of Bcr-Abl-transformed leukaemic cells.

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How do retroviral oncogenes induce transformation in avian erythroid cells?

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1985.0086 ◽

1985 ◽

Vol 226 (1242) ◽

pp. 121-126 ◽

Cited By ~ 6

Keyword(s):

Early Stage ◽

Erythroid Differentiation ◽

Erythroid Cells ◽

Self Renewal ◽

Erythroid Precursor ◽

Erythroid Precursors ◽

Leukaemic Cells ◽

Transforming Proteins

The v-erb B oncogene, as well as other oncogenes of the src -gene family transform immature erythroid cells from chick bone marrow in vivo and in vitro . The erb B-transformed erythroid cells differ from normal late erythroid precursors (CFU-E) in that they have acquired the capacity to undergo self-renewal as well as to differentiate terminally. They also do not require the normal erythroid differentiation hormone, erythro-poietin, for either process. Cooperation of v-erb B with a second oncogene, v-erb A, results in a differentiation arrest of the transformed cells, which now only use the self-renewal pathway. Studies with conditional and non-conditional mutants in both v-erb B and v-erb A will be presented to elucidate further how the transforming proteins encoded by these oncogenes, gp74 erb B and gp75 gag-erb A , affect the differentiation programme of the infected erythroid precursor with the outcome of hormone-independent leukaemic cells arrested at an early stage of erythroid differentiation.

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Infant leukaemia – faithful models, cell of origin and the niche

Disease Models & Mechanisms ◽

10.1242/dmm.049189 ◽

2021 ◽

Vol 14 (10) ◽

Author(s):

Alasdair Duguid ◽

Domenico Mattiucci ◽

Katrin Ottersbach

Keyword(s):

Ex Vivo ◽

Central Nervous System Involvement ◽

Biological Entity ◽

Single Mutation ◽

Cell Of Origin ◽

Established Disease ◽

Leukaemic Cells ◽

Distinguishing Features

ABSTRACT For patients and their families, the diagnosis of infant leukaemia is devastating. This disease has not seen the improvements in outcomes experienced with other paediatric leukaemias and it is becoming ever more apparent that infant leukaemia is a distinct biological entity. Insights into some of the distinguishing features of infant leukaemia, such as a single mutation – the MLL-gene rearrangement, the biology of disease aggressiveness and lineage plasticity, and the high incidence of central nervous system involvement, are likely to be gained from understanding the interactions between leukaemic cells and their environment or niche. The origins of infant leukaemia lie in the embryonic haematopoietic system, which is characterised by shifting locations and dynamic changes in the microenvironment. Understanding this foetal or embryonic context is integral to understanding infant leukaemia development. Owing to its rarity and prenatal origins, developing accurate modelling systems for further investigation of infant leukaemia is essential. In this Review, we discuss how available in vitro, ex vivo and in vivo infant leukaemia models contribute to our current understanding of the leukaemia niche in embryonic development, established disease and specialised non-haematopoietic niches. The mechanistic insights provided by accurate models will help identify viable novel therapeutic options.

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Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053425 ◽

1982 ◽

Vol 40 ◽

pp. 142-145

Author(s):

E. J. Kollar

Keyword(s):

Connective Tissue ◽

Oral Mucosa ◽

Basal Lamina ◽

Functional Derivatives ◽

Specific Source ◽

Dental Epithelium ◽

Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

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Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053711 ◽

1982 ◽

Vol 40 ◽

pp. 210-211

Author(s):

M.J. Murphy ◽

R.R. Price ◽

J.C. Sloman

Keyword(s):

Cultured Cells ◽

Human Tumor ◽

Cell Type ◽

Tumor Mass ◽

Initial Cell ◽

Cloning Assay ◽

Human Tumor Cloning ◽

The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084120 ◽

1978 ◽

Vol 36 (2) ◽

pp. 650-651

Author(s):

Raul I. Garcia ◽

Evelyn A. Flynn ◽

George Szabo

Keyword(s):

Direct Injection ◽

Skin Pigmentation ◽

Freeze Fracture ◽

Pigment Granule ◽

Time Lapse ◽

Ultrastructural Level ◽

Lanthanum Tracer ◽

A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

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