The suppression of malignancy by terminal differentiation: evidence from hybrids between tumour cells and keratinocytes

1987 ◽  
Vol 87 (3) ◽  
pp. 383-388
Author(s):  
H. Harris ◽  
M.E. Bramwell
Keyword(s):  
Terminal Differentiation ◽  
Human Keratinocytes ◽  
Tumour Cells ◽  
Human Cells ◽  
Hybrid Cells ◽  
Progressive Growth ◽  
Cultivation In Vitro

When malignant human cells are crossed with diploid human keratinocytes, malignancy, as defined by progressive growth in vivo, is suppressed so long as the hybrid cells continue to produce involucrin, a protein that characterizes terminal differentiation in the keratinocyte. When, on continued cultivation in vitro, the cells lose the ability to produce involucrin, they reacquire the ability to grow progressively in the animal.

scholarly journals A protein phosphatase network controls the temporal and spatial dynamics of differentiation commitment in human epidermis

2017 ◽  
Author(s):  
Ajay Mishra ◽  
Angela Oliveira Pisco ◽  
Benedicte Oules ◽  
Tony Ly ◽  
Kifayathullah Liakath-Ali ◽  
...  
Keyword(s):  
Stem Cell ◽  
Terminal Differentiation ◽  
Human Keratinocytes ◽  
Cell Renewal ◽  
Stable States ◽  
Primary Human Keratinocytes ◽  
Network Modelling ◽  
Epidermal Homeostasis

AbstractEpidermal homeostasis depends on a balance between stem cell renewal and terminal differentiation1,2. While progress has been made in characterising the stem and differentiated cell compartments3, the transition between the two cell states, termed commitment4, is poorly understood. Here we characterise commitment by integrating transcriptomic and proteomic data from disaggregated primary human keratinocytes held in suspension for up to 12h. We have previously shown that commitment begins at approximately 4h and differentiation is initiated by 8h5. We find that cell detachment induces a network of protein phosphatases. The pro-commitment phosphatases – including DUSP6, PPTC7, PTPN1, PTPN13 and PPP3CA – promote terminal differentiation by negatively regulating ERK MAPK and positively regulating key API transcription factors. Their activity is antagonised by concomitant upregulation of the anti-commitment phosphatase DUSP10. The phosphatases form a dynamic network of transient positive and negative interactions, with DUSP6 predominating at commitment. Boolean network modelling identifies a mandatory switch between two stable states (stem cell and differentiated cell) via an unstable (committed) state. In addition phosphatase expression is spatially regulated relative to the location of stem cells, both in vivo and in response to topographical cues in vitro. We conclude that an auto-regulatory phosphatase network maintains epidermal homeostasis by controlling the onset and duration of commitment.

scholarly journals Epigenetics changes caused by the fusion of human embryonic stem cell and ovarian cancer cells

2016 ◽  
Vol 36 (5) ◽  
Author(s):  
Ke He ◽  
Hu Qu ◽  
Li-Nan Xu ◽  
Jun Gao ◽  
Fu-Yi Cheng ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Stem Cells ◽  
Cancer Cells ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Tumour Cells ◽  
Ovarian Cancer Cells ◽  
Hybrid Cells

To observe the effect of gene expression and tumorigenicity in hybrid cells of human embryonic stem cells (hESCs) and ovarian cancer cells in vitro and in vivo using a mouse model, and to determine its feasibility in reprogramming tumour cells growth and apoptosis, for a potential exploration of the role of hESCs and tumour cells fusion in the management of ovarian cancer. Stable transgenic hESCs (H1) and ovarian cancer cell line OVCAR-3 were established before fusion, and cell fusion system was established to analyse the related indicators. PTEN expression in HO-H1 cells was higher than those in the parental stem cells and lower than those in parental tumour cells; the growth of OV-H1 (RFP+GFP) hybrid cells with double fluorescence expressions were obviously slower than that of human embryonic stem cells and OVCAR-3 ovarian cancer cells. The apoptosis signal of the OV-H1 hybrid cells was significantly higher than that of the hESCs and OVCAR-3 ovarian cancer cells. In vivo results showed that compared with 7 days, 28 days and 35 days after inoculation of OV-H1 hybrid cells; also, apoptotic cell detection indicated that much stronger apoptotic signal was found in OV-H1 hybrid cells inoculated mouse. The hESCs can inhibit the growth of OVCAR-3 cells in vitro by suppressing p53 and PTEN expression to suppress the growth of tumour that may be achieved by inducing apoptosis of OVCAR-3 cells. The change of epigenetics after fusion of ovarian cancer cells and hESCs may become a novel direction for treatment of ovarian cancer.

The Analysis of Malignancy by Cell Fusion

1971 ◽  
Vol 8 (3) ◽  
pp. 681-692
Author(s):  
F. WIENER ◽  
G. KLEIN ◽  
H. HARRIS
Keyword(s):  
Tumour Cells ◽  
Hybrid Cells ◽  
Recessive Character ◽  
Parental Chromosome ◽  
Diploid Fibroblasts ◽  
Progressive Loss ◽  
L Cell ◽  
Very High

Diploid fibroblasts were fused with cells of two highly malignant near euploid tumours, a sarcoma induced by polyoma virus and a spontaneous carcinoma; the resulting hybrid cells were tested for their ability to grow progressively in vivo. In the case of the sarcoma/fibroblast hybrids, 15 clonal populations, each derived from a separate primary fusion, were examined. Most of these populations already showed substantial losses of chromosomes by the time enough cells had been generated to permit chromosomal analysis; but a few clones were isolated with chromosomal constitutions approximating to the sum of the 2 parental chromosome sets. Those clones that had undergone substantial chromosomal losses were highly tumorigenic, but some of the clones that contained the complete, or almost complete, chromosome sets of both parent cells, showed a greatly reduced take incidence. Initially these clones produced very few tumours, but the take incidence rose as continued cultivation of the cells in vitro resulted in progressive loss of chromosomes. In the case of the carcinoma/fibroblast hybrids, clonal populations with very high chromosome numbers were selected for special study. These were also found to have a very low take incidence, comparable to that of the hybrids formed by the fusion of the tumour cells with L cell derivatives. None of the tumours produced by the injection of either the sarcoma/fibroblast or carcinoma/fibroblast hybrids were composed of cells containing chromosome complements corresponding to the sum of the 2 parental chromosome sets; all the tumours were formed by selective overgrowth of cells from which some chromosomes had been eliminated. These results indicate that the malignancy of the tumour cells can be suppressed by diploid fibroblasts as well as by the L cell derivatives, but that the rapid chromosome losses characteristic of hybrids between these tumour cells and diploid fibroblasts generate malignant segregants with much greater frequency. In the range of material examined in the present experiments malignancy thus behaves as if it were a recessive character.

The Analysis of Malignancy by Cell Fusion

1973 ◽  
Vol 12 (1) ◽  
pp. 253-261
Author(s):  
F. WIENER ◽  
G. KLEIN ◽  
H. HARRIS
Keyword(s):  
Tumour Cell ◽  
Tumour Cells ◽  
Hybrid Cells ◽  
Wild Type ◽  
Malignant Phenotype ◽  
L Cell ◽  
Progressive Growth ◽  
Mouse Tumour ◽  
Derivatives Of

Previous experiments showed that when a range of different highly malignant mouse tumour cells were fused with L cell derivatives of low tumorigenicity, the resulting hybrid cells, so long as they retained something close to the complete chromosome sets of both parent cells, had little or no ability to grow progressively in vivo. Tumours arising from the injection of such hybrids were produced not by progressive growth of the cells injected, but by selective overgrowth of cells from which certain specific, but as yet unidentified, chromosomes had been eliminated. In the present experiments the same malignant mouse tumour cells were fused with a highly malignant L cell derivative selected from the wild type cell population by passage through the animal. In all cases the resulting hybrid cells were found to be highly malignant; and the chromosome constitutions of the tumours arising from the injection of these hybrids were not significantly different from those of the cells injected. These findings confirm the interpretation given to the previous work; the L cell derivatives of low tumorigenicity contribute to the hybrid cells some factor, linked to specific chromosomes, that suppresses the malignant character of the tumour cell, and this suppression is removed, with consequent reappearance of the malignant phenotype, when certain chromosomes are eliminated.

scholarly journals Cathepsin L plays a key role in SARS-CoV-2 infection in humans and humanized mice and is a promising target for new drug development

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Miao-Miao Zhao ◽  
Wei-Li Yang ◽  
Fang-Yuan Yang ◽  
Li Zhang ◽  
Wei-Jin Huang ◽  
...  
Keyword(s):  
Drug Development ◽  
Cathepsin L ◽  
Human Cells ◽  
New Drugs ◽  
Disease Course ◽  
Promising Target ◽  
First Time

AbstractTo discover new drugs to combat COVID-19, an understanding of the molecular basis of SARS-CoV-2 infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated after SARS-CoV-2 infection and was positively correlated with disease course and severity. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cells in vitro and human ACE2 transgenic mice in vivo, while CTSL overexpression, in turn, enhanced pseudovirus infection in human cells. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity after SARS-CoV-2 pseudovirus infection and prevented infection both in vitro and in vivo. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.

scholarly journals Human Keratinocytes Adopt Neuronal Fates After In Utero Transplantation in the Developing Rat Brain

2021 ◽  
Vol 30 ◽  
pp. 096368972097821
Author(s):  
Andrea Tenorio-Mina ◽  
Daniel Cortés ◽  
Joel Esquivel-Estudillo ◽  
Adolfo López-Ornelas ◽  
Alejandro Cabrera-Wrooman ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Ectopic Expression ◽  
Neural Induction ◽  
Human Keratinocytes ◽  
Differentiation Potential ◽  
Neuronal Proteins ◽  
Green Fluorescent

Human skin contains keratinocytes in the epidermis. Such cells share their ectodermal origin with the central nervous system (CNS). Recent studies have demonstrated that terminally differentiated somatic cells can adopt a pluripotent state, or can directly convert its phenotype to neurons, after ectopic expression of transcription factors. In this article we tested the hypothesis that human keratinocytes can adopt neural fates after culturing them in suspension with a neural medium. Initially, keratinocytes expressed Keratins and Vimentin. After neural induction, transcriptional upregulation of NESTIN, SOX2, VIMENTIN, SOX1, and MUSASHI1 was observed, concomitant with significant increases in NESTIN detected by immunostaining. However, in vitro differentiation did not yield the expression of neuronal or astrocytic markers. We tested the differentiation potential of control and neural-induced keratinocytes by grafting them in the developing CNS of rats, through ultrasound-guided injection. For this purpose, keratinocytes were transduced with lentivirus that contained the coding sequence of green fluorescent protein. Cell sorting was employed to select cells with high fluorescence. Unexpectedly, 4 days after grafting these cells in the ventricles, both control and neural-induced cells expressed green fluorescent protein together with the neuronal proteins βIII-Tubulin and Microtubule-Associated Protein 2. These results support the notion that in vivo environment provides appropriate signals to evaluate the neuronal differentiation potential of keratinocytes or other non-neural cell populations.

scholarly journals Macrophage oxygen-dependent antimicrobial activity. III. Enhanced oxidative metabolism as an expression of macrophage activation.

1980 ◽  
Vol 152 (6) ◽  
pp. 1596-1609 ◽  
Author(s):  
H W Murray ◽  
Z A Cohn
Keyword(s):  
Antimicrobial Activity ◽  
Oxidative Metabolism ◽  
Macrophage Activation ◽  
Systemic Infection ◽  
Peritoneal Macrophages ◽  
H2o2 Production ◽  
Oxygen Intermediates ◽  
Cultivation In Vitro

The capacity of 15 separate populations of mouse peritoneal macrophages to generate and release H2O2 (an index of oxidative metabolism) was compared with their ability to inhibit the intracellular replication of virulent Toxoplasma gondii. Resident macrophages and those elicited by inflammatory agents readily supported toxoplasma multiplication and released 4-20X less H2O2 than macrophages activated in vivo by systemic infection with Bacille Calmette-Guérin or T. gondii, or by immunization with Corynebacterium parvum. Immunologically activated cells consistently displayed both enhanced H2O2 production and antitoxoplasma activity. Exposure to lymphokines generated from cultures of spleen cells from T. gondii immune mice and toxoplasma antigen preserved both the antitoxoplasma activity and the heightened H2O2 release of toxoplasma immune and immune-boosted macrophages, which otherwise were lost after 48-72 h of cultivation. In vitro activation of resident and chemically-elicited cells by 72 h of exposure to mitogen- and antigen-prepared lymphokines, conditions that induce trypanocidal (5) and leishmanicidal activity (14), stimulated O2- and H2O2 release, and enhanced nitroblue tetrazolium reduction in response to toxoplasma ingestion. Such treatment, however, failed to confer any antitoxoplasma activity, indicating that intracellular pathogens may vary in their susceptibility to macrophage microbicidal mechanisms, including specific oxygen intermediates. In contrast, cocultivating normal macrophages with lymphokine plus heart infusion broth for 18H rendered these cells toxoplasmastatic. This in vitro-acquired activity was inhibited by scavengers of O2-, H2O2, OH., and 1O2, demonstrating a role for oxidative metabolites in lymphokine-induced enhancement of macrophage antimicrobial activity. These findings indicate that augmented oxidative metabolism is an consistent marker of macrophage activation, and that oxygen intermediates participate in the resistance of both in vivo- and vitro-activated macrophages toward the intracellular parasite, T. gondii.

Mode of action of amphotericin B on chick embryo fibroblasts and on mouse Ehrlich tumour cells: a cytological and cytochemical analysis

1975 ◽  
Vol 18 (3) ◽  
pp. 441-451
Author(s):  
F. De Paermentier ◽  
R. Bassleer ◽  
A. Lepoint ◽  
C. Desaive ◽  
G. Goessens ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Amphotericin B ◽  
Tumour Cells ◽  
Total Protein Content ◽  
Cell Multiplication ◽  
Cytochemical Analysis ◽  
Ehrlich Ascites ◽  
Embryo Fibroblasts

Chick embryo fibroblasts cultivated in vitro and Ehrlich ascites tumor cells (in vivo or in vitro) have been treated with amphotericin B. Cell multiplication is strongly inhibited. Large clear zones appear in the fibroblast nucleoi (phase-contrast and electron-microscope observations). Many treated fibroblasts and tumour cells have a high DNA content (pre-mitotic or polyploid level; measurements by cytophotometry). However, the RNA content (cytophotometry) and the total protein content (cytophotometry and micro-interferometry) are relatively low in the tumour cells. As shown by autoradiography, DNA synthesis is active but RNA synthesis and, in some cases, protein synthesis are inhibited. Due to this unbalanced growth, the cells cannot divide.

The extracellular matrix of hybrids between melanoma cells and normal fibroblasts

1988 ◽  
Vol 91 (2) ◽  
pp. 281-286
Author(s):  
M.C. Copeman ◽  
H. Harris
Keyword(s):  
Extracellular Matrix ◽  
Protease Activity ◽  
Malignant Tumour ◽  
Melanoma Cells ◽  
Chromosome Loss ◽  
Type I ◽  
Chromosome 4 ◽  
Hybrid Cells

It has been shown that when malignant tumour cells are fused with normal fibroblasts the suppression of malignancy in the hybrids is linked to their ability to produce a collagenous extracellular matrix in vivo. When, as a consequence of chromosome loss, segregants arise that reacquire malignancy, these do not produce any detectable matrix. In this paper we examine the main components of the extracellular matrix produced in vitro by hybrids between malignant mouse melanoma cells and normal mouse fibroblasts. Hybrids in which malignancy is suppressed synthesize about ten times as much type 1 procollagen as the malignant segregants derived from them; they also retain more fibronectin in the cell layer and release less protease activity into the medium. Malignant segregants more closely resemble the parental melanoma cells in producing fibronectin and mainly types IV and V procollagen. When hybrid cells in which malignancy is initially suppressed are grown continuously in vitro, the production of type I procollagen declines, and the production of type V procollagen and the release of protease activity into the medium increase. These changes, which are associated with the loss from the hybrid cells of both copies of the chromosome 4 derived from the parental fibroblast, predict the reacquisition of malignancy when the cells are inoculated into mice. It is possible that one gene or set of genes located on chromosome 4 determines both the execution of the fibroblast differentiation programme and the suppression of malignancy.

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