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1.
Exp Cell Res ; 439(1): 114048, 2024 Jun 01.
Article de Anglais | MEDLINE | ID: mdl-38697275

RÉSUMÉ

Prenatal surgery for the treatment of spina bifida (myelomeningocele, MMC) significantly enhances the neurological prognosis of the patient. To ensure better protection of the spinal cord by large defects, the application of skin grafts produced with cells gained from the amniotic fluid is presently studied. In order to determine the most appropriate cells for this purpose, we tried to shed light on the extremely complex amniotic fluid cellular composition in healthy and MMC pregnancies. We exploited the potential of micro-Raman spectroscopy to analyse and characterize human amniotic fluid cells in total and putative (cKit/CD117-positive) stem cells of fetuses with MMC in comparison with amniotic fluid cells from healthy individuals, human fetal dermal fibroblasts and adult adipose derived stem cells. We found that (i) the differences between healthy and MMC amniocytes can be attributed to specific spectral regions involving collagen, lipids, sugars, tryptophan, aspartate, glutamate, and carotenoids, (ii) MMC amniotic fluid contains two particular cell populations which are absent or reduced in normal pregnancies, (iii) the cKit-negative healthy amniocyte subpopulation shares molecular features with human fetal fibroblasts. On the one hand we demonstrate a different amniotic fluid cellular composition in healthy and MMC pregnancies, on the other our work confirms micro-Raman spectroscopy to be a valuable tool for discriminating cell populations in unknown mixtures of cells.


Sujet(s)
Liquide amniotique , Foetus , Myéloméningocèle , Analyse spectrale Raman , Humains , Analyse spectrale Raman/méthodes , Liquide amniotique/cytologie , Liquide amniotique/métabolisme , Myéloméningocèle/métabolisme , Myéloméningocèle/anatomopathologie , Femelle , Grossesse , Foetus/métabolisme , Fibroblastes/métabolisme , Fibroblastes/anatomopathologie , Cellules cultivées , Adulte
2.
Acta Biomater ; 134: 215-227, 2021 10 15.
Article de Anglais | MEDLINE | ID: mdl-34303011

RÉSUMÉ

Severe injuries to skin including hypodermis require full-thickness skin replacement. Here, we bioengineered a tri-layered human skin substitute (TLSS) containing the epidermis, dermis, and hypodermis. The hypodermal layer was generated by differentiation of human adipose stem cells (ASC) in a collagen type I hydrogel and combined with a prevascularized dermis consisting of human dermal microvascular endothelial cells and fibroblasts, which arranged into a dense vascular network. Subsequently, keratinocytes were seeded on top to generate the epidermal layer of the TLSS. The differentiation of ASC into adipocytes was confirmed in vitro on the mRNA level by the presence of adiponectin, as well as by the expression of perilipin and FABP-4 proteins. Moreover, functional characteristics of the hypodermis in vitro and in vivo were evaluated by Oil Red O, BODIPY, and AdipoRed stainings visualizing intracellular lipid droplets. Further, we demonstrated that both undifferentiated ASC and mature adipocytes present in the hypodermis influenced the keratinocyte maturation and homeostasis in the skin substitutes after transplantation. In particular, an enhanced secretion of TGF-ß1 by these cells affected the epidermal morphogenesis as assessed by the expression of key proteins involved in the epidermal differentiation including cytokeratin 1, 10, 19 and cornified envelope formation such as involucrin. Here, we propose a novel functional hypodermal-dermo-epidermal tri-layered skin substitute containing blood capillaries that efficiently promote regeneration of skin defects. STATEMENT OF SIGNIFICANCE: The main objective of this study was to develop and assess the usefulness of a tri-layered human prevascularized skin substitute (TLSS) containing an epidermis, dermis, and hypodermis. The bioengineered hypodermis was generated from human adipose mesenchymal stem cells (ASC) and combined with a prevascularized dermis and epidermis. The TLSS represents an exceptional model for studying the role of cell-cell and cell-matrix interactions in vitro and in vivo. In particular, we observed that enhanced secretion of TGF-ß1 in the hypodermis exerted a profound impact on fibroblast and keratinocyte differentiation, as well as epidermal barrier formation and homeostasis. Therefore, improved understanding of the cell-cell interactions in such a physiological skin model is essential to gain insights into different aspects of wound healing.


Sujet(s)
Peau artificielle , Bioingénierie , Derme , Cellules endothéliales , Fibroblastes , Humains , Kératinocytes , Peau , Tissu sous-cutané , Ingénierie tissulaire
3.
Sci Rep ; 11(1): 5418, 2021 03 08.
Article de Anglais | MEDLINE | ID: mdl-33686145

RÉSUMÉ

Bone regeneration is a complex process and the clinical translation of tissue engineered constructs (TECs) remains a challenge. The combination of biomaterials and mesenchymal stem cells (MSCs) may enhance the healing process through paracrine effects. Here, we investigated the influence of cell format in combination with a collagen scaffold on key factors in bone healing process, such as mineralization, cell infiltration, vascularization, and ECM production. MSCs as single cells (2D-SCs), assembled into microtissues (3D-MTs) or their corresponding secretomes were combined with a collagen scaffold and incubated on the chicken embryo chorioallantoic membrane (CAM) for 7 days. A comprehensive quantitative analysis was performed on a cellular level by histology and by microcomputed tomography (microCT). In all experimental groups, accumulation of collagen and glycosaminoglycan within the scaffold was observed over time. A pronounced cell infiltration and vascularization from the interface to the surface region of the CAM was detected. The 3D-MT secretome showed a significant mineralization of the biomaterial using microCT compared to all other conditions. Furthermore, it revealed a homogeneous distribution pattern of mineralization deposits in contrast to the cell-based scaffolds, where mineralization was only at the surface. Therefore, the secretome of MSCs assembled into 3D-MTs may represent an interesting therapeutic strategy for a next-generation bone healing concept.


Sujet(s)
Os et tissu osseux/métabolisme , Calcification physiologique , Chorioallantoïde , Cellules souches mésenchymateuses/métabolisme , Sécrétome/métabolisme , Structures d'échafaudage tissulaires/composition chimique , Animaux , Os et tissu osseux/imagerie diagnostique , Embryon de poulet , Femelle , Humains , Suidae , Microtomographie aux rayons X
4.
Biomolecules ; 10(9)2020 09 22.
Article de Anglais | MEDLINE | ID: mdl-32971982

RÉSUMÉ

The cardioprotective properties of extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) are currently being investigated in preclinical studies. Although microRNAs (miRNAs) encapsulated in EVs have been identified as one component responsible for the cardioprotective effect of MSCs, their potential off-target effects have not been sufficiently characterized. In the present study, we aimed to investigate the miRNA profile of EVs isolated from MSCs that were derived from cord blood (CB) and adipose tissue (AT). The identified miRNAs were then compared to known targets from the literature to discover possible adverse effects prior to clinical use. Our data show that while many cardioprotective miRNAs such as miR-22-3p, miR-26a-5p, miR-29c-3p, and miR-125b-5p were present in CB- and AT-MSC-derived EVs, a large number of known oncogenic and tumor suppressor miRNAs such as miR-16-5p, miR-23a-3p, and miR-191-5p were also detected. These findings highlight the importance of quality assessment for therapeutically applied EV preparations.


Sujet(s)
Tissu adipeux/cytologie , Vésicules extracellulaires/génétique , Sang foetal/cytologie , Analyse de profil d'expression de gènes/méthodes , Cellules souches mésenchymateuses/métabolisme , microARN/génétique , Adulte , Cellules cultivées , Analyse de regroupements , Vésicules extracellulaires/métabolisme , Vésicules extracellulaires/ultrastructure , Femelle , Humains , Mâle , Cellules souches mésenchymateuses/cytologie , microARN/classification , Microscopie électronique à transmission , Adulte d'âge moyen , Transduction du signal/génétique
5.
Praxis (Bern 1994) ; 105(9): 517-21, 2016 Apr 27.
Article de Allemand | MEDLINE | ID: mdl-27120213

RÉSUMÉ

As practitioners, we are faced in practice daily with the question about the optimal diet. Nevertheless, nutrition covers only a very small part of our medical training. A look back in the history of man shows that the human body was set to a predominantly plant-based diet for millions of years. With the introduction of factory farming and industrial food processing several hundred years ago, the current Western diet has been consisting to a large extent of animal products, leading to a number of chronic diseases such as hypertension, hypercholesterolemia, coronary heart disease, vascular dementia, diabetes, and to an increase of cancer. Many of these diseases are preventable, some even reversible when resorting to a whole-foods plant-based diet. This review work is intended to provide the practitioner with the necessary knowledge and the scientific facts.


Sujet(s)
Politique nutritionnelle , Maladie chronique/épidémiologie , Maladie chronique/prévention et contrôle , Maladie coronarienne/étiologie , Maladie coronarienne/prévention et contrôle , Études transversales , Régime végétalien , Régime végétarien , Régime occidental , Médecine générale , Humains , Besoins nutritifs
6.
Biomaterials ; 34(10): 2428-41, 2013 Mar.
Article de Anglais | MEDLINE | ID: mdl-23332174

RÉSUMÉ

Stem cells have been repeatedly suggested for cardiac regeneration after myocardial infarction (MI). However, the low retention rate of single cell suspensions limits the efficacy of current therapy concepts so far. Taking advantage of three dimensional (3D) cellular self-assembly prior to transplantation may be beneficial to overcome these limitations. In this pilot study we investigate the principal feasibility of intramyocardial delivery of in-vitro generated stem cell-based 3D microtissues (3D-MTs) in a porcine model. 3D-MTs were generated from iron-oxide (MPIO) labeled human adipose-tissue derived mesenchymal stem cells (ATMSCs) using a modified hanging-drop method. Nine pigs (33 ± 2 kg) comprising seven healthy ones and two with chronic MI in the left ventricle (LV) anterior wall were included. The pigs underwent intramyocardial transplantation of 16 × 10(3) 3D-MTs (1250 cells/MT; accounting for 2 × 10(7) single ATMSCs) into the anterior wall of the healthy pigs (n = 7)/the MI border zone of the infarcted (n = 2) of the LV using a 3D NOGA electromechanical mapping guided, transcatheter based approach. Clinical follow-up (FU) was performed for up to five weeks and in-vivo cell-tracking was performed using serial magnet resonance imaging (MRI). Thereafter, the hearts were harvested and assessed by PCR and immunohistochemistry. Intramyocardial transplantation of human ATMSC based 3D-MTs was successful in eight animals (88.8%) while one pig (without MI) died during the electromechanical mapping due to sudden cardiac-arrest. During FU, no arrhythmogenic, embolic or neurological events occurred in the treated pigs. Serial MRI confirmed the intramyocardial presence of the 3D-MTs by detection of the intracellular iron-oxide MPIOs during FU. Intramyocardial retention of 3D-MTs was confirmed by PCR analysis and was further verified on histology and immunohistochemical analysis. The 3D-MTs appeared to be viable, integrated and showed an intact micro architecture. We demonstrate the principal feasibility and safety of intramyocardial transplantation of in-vitro generated stem cell-based 3D-MTs. Multimodal cell-tracking strategies comprising advanced imaging and in-vitro tools allow for in-vivo monitoring and post-mortem analysis of transplanted 3D-MTs. The concept of 3D cellular self-assembly represents a promising application format as a next generation technology for cell-based myocardial regeneration.


Sujet(s)
Transplantation de cellules souches mésenchymateuses/méthodes , Animaux , Femelle , Défaillance cardiaque/thérapie , Humains , Imagerie par résonance magnétique , Infarctus du myocarde/thérapie , Myocarde/métabolisme , Médecine régénérative , Suidae
7.
Dermatology ; 220(3): 223-5, 2010.
Article de Anglais | MEDLINE | ID: mdl-20110638

RÉSUMÉ

BACKGROUND: Local anesthesia has been widely accepted as the standard of care in liposuction. Anesthesia is achieved with a standard tumescent solution, and lidocaine is most often used at a concentration of 500 mg/l. OBJECTIVE: To evaluate the efficacy of a 400 mg/l lidocaine concentration in tumescent liposuction. METHODS: We performed a randomized clinical trial on 200 consecutive patients undergoing lipoaspiration. Patients were divided into two groups: group A (n = 100) received tumescent solution with a lidocaine concentration of 500 mg/l, in group B (n = 100) lidocaine levels were reduced to 400 mg/l. Pain was assessed twice during the procedure, at infiltration and while liposuction was performed. Patients rated their pain level on a numeric rating scale from 0 to 10, with 10 being the worst possible pain. RESULTS: Tumescent solution containing a lidocaine concentration of 400 mg/l provided effective local anesthesia during lipoaspiration. There was no statistically significant difference in the pain level between the two groups. CONCLUSION: We propose the use of a lower lidocaine concentration of 400 mg/l in the tumescent solution compared to the originally described solution containing 500 mg/l. This is of particular interest when multiple body parts or larger areas are to be treated to avoid lidocaine toxicity.


Sujet(s)
Anesthésiques locaux/administration et posologie , Lidocaïne/administration et posologie , Lipectomie , Adulte , Sujet âgé , Femelle , Humains , Mâle , Adulte d'âge moyen , Jeune adulte
8.
Dermatology ; 213(3): 215-7, 2006.
Article de Anglais | MEDLINE | ID: mdl-17033170

RÉSUMÉ

BACKGROUND: Axillary hyperhidrosis is a common and most distressing problem, which can be addressed by a variety of treatment modalities. OBJECTIVE: To assess the value of tumescent suction curettage in the treatment of axillary hyperhidrosis. METHODS: 63 patients (39 female, 25 male; mean age 30.3 +/- 7.6 years) with axillary hyperhidrosis were enrolled in the study. All patients were treated in an outpatient setting with tumescent suction curettage of the axillary cavity, using two entry sites. The results were evaluated with the iodine-starch test after 4 weeks and after 6 months. Two years after the procedure, patient satisfaction was evaluated as 'satisfied', 'partially satisfied' or 'dissatisfied'. RESULTS: None of the patients had early postoperative complications of infection or seroma. All patients had a marked reduction of hyperhidrosis after 4 weeks, confirmed by the iodine-starch test. After 6 months, 15 patients had high sweat rates and asked for repeat surgery. Two years after the procedure, 49 patients were satisfied, 11 patients were partially satisfied and 3 patients were dissatisfied. CONCLUSION: Tumescent suction curettage is a safe and effective treatment of axillary hyperhidrosis resulting in a high level of patient satisfaction. Some patients will need repeat surgery. Suction curettage, however, should not be used as the first line of treatment in axillary hyperhidrosis.


Sujet(s)
Hyperhidrose/thérapie , Curetage aspiratif , Adulte , Aisselle , Toxines botuliniques de type A/usage thérapeutique , Femelle , Humains , Iode , Mâle , Agents neuromusculaires/usage thérapeutique , Satisfaction des patients , Résultat thérapeutique
9.
Dermatology ; 213(2): 140-3, 2006.
Article de Anglais | MEDLINE | ID: mdl-16902291

RÉSUMÉ

BACKGROUND: Tumescent power liposuction is widely used on various parts of the body for minimal-access lipectomy. The undesired fat deposits are injected with tumescence fluid containing saline, epinephrine, bicarbonate and lidocaine; the latter is used as the only source of pain control. The fat is then removed using vibrating microcannulas. OBJECTIVE: To evaluate the value of tumescent power liposuction in the treatment of the enlarged male breast. METHODS: 38 male patients aged 23-64 years (mean age 39.8 +/- 9.7 years) with enlarged breasts were enrolled in the study. In 32 patients, breasts were enlarged due to fat tissue, and the ductal glands were not palpable (pseudogynecomastia). In 6 patients, the ductal glands were enlarged (gynecomastia). All patients were treated with tumescent liposuction over a 2-year period using a single entry site from the axillary fossa. Both fat as well as ductal and stromal tissue were removed by microcannulas. RESULTS: None of the patients had early postoperative complications of infection, hematoma or seroma. There were no treatment-induced asymmetries, contour deformities or irregularities. No open excision or skin reduction procedures were required. CONCLUSION: Tumescent liposuction using a single entry site in the axillary fossa is a minimally invasive technique to treat enlarged male breasts. Both fat (pseudogynecomastia in adipose patients) as well as ductal and stromal tissue (in gynecomastia) can be removed with tumescent liposuction, resulting in a high level of patient satisfaction.


Sujet(s)
Gynécomastie/chirurgie , Lipectomie/méthodes , Adulte , Études de suivi , Humains , Mâle , Adulte d'âge moyen , Résultat thérapeutique
10.
Melanoma Res ; 13(2): 213-7, 2003 Apr.
Article de Anglais | MEDLINE | ID: mdl-12690309

RÉSUMÉ

It has been shown that the co-occurrence of melanoma and pre-existing naevus is not a random event and that acquired naevi may be precursors of melanoma. A critical area of chromosomal loss at 9p21 has been implicated in the genesis of malignant melanoma, representing a site of frequent somatic chromosomal deletions in melanoma. Allelic deletions within this chromosomal region most often include the tumour suppressor gene p16. The objective of this study was to search for allelic deletions on chromosome 9p21 in naevus cell clusters. A microdissection-based approach was used to analyse 30 archived primary cutaneous melanomas and associated naevi for loss of heterozygosity (LOH) at 9p21 using the polymorphic DNA markers D9S171 and IFNA. LOH was detected in 10 out of 27 informative naevi (37%) at D9S171 and in eight out of 19 (42%) at IFNA in the dissected naevus cell clusters, and in nine out of 27 (33%) at D9S171 and seven out of 19 (36%) at IFNA in the associated melanomas. In eight out of 46 (17%) cases, LOH was detected simultaneously in the naevus and the associated melanoma using both markers. Our results suggest a causal relationship for the development of melanoma within a pre-existent associated naevus. These data support the hypothesis that lesions within 9p21 play an important role in early melanoma development, since these genetic alterations are found in histologically benign melanoma-associated naevi.


Sujet(s)
Mélanome/diagnostic , Naevus/diagnostic , Tumeurs cutanées/diagnostic , Allèles , Chromosomes humains de la paire 9 , ADN/métabolisme , Syndrome du naevus dysplasique/diagnostic , Syndrome du naevus dysplasique/génétique , Délétion de gène , Gènes p16 , Marqueurs génétiques , Humains , Perte d'hétérozygotie , Mélanome/génétique , Répétitions microsatellites , Naevus/génétique , Réaction de polymérisation en chaîne , Polymorphisme génétique , États précancéreux , Tumeurs cutanées/génétique
11.
Am J Clin Dermatol ; 4(4): 273-6, 2003.
Article de Anglais | MEDLINE | ID: mdl-12680804

RÉSUMÉ

Gram-negative folliculitis may be the result of long-term antibacterial treatment in acne patients. It is caused by bacterial interference and replacement of the Gram-positive flora of the facial skin and the mucous membranes of the nose and infestation with Gram-negative bacteria. These Gram-negative bacteria include Escherischia coli, Pseudomonas aeruginosa, Serratia marescens, Klebsiella and Proteus mirabilis. The occurrence of Gram-negative folliculitis should be considered in acne patients in whom oral treatment with tetracyclines has not resulted in a significant improvement of acne lesions after 3-6 months' treatment. The occurrence of Gram-negative folliculitis in acne patients is believed to be generally underestimated, since correct sampling and bacteriology is rarely performed by clinicians. Gram-negative folliculitis in acne and rosacea patients is best treated with isotretinoin (0.5-1 mg/kg daily for 4-5 months).


Sujet(s)
Produits dermatologiques/usage thérapeutique , Folliculite/traitement médicamenteux , Bactéries à Gram négatif/isolement et purification , Infections bactériennes à Gram négatif/traitement médicamenteux , Isotrétinoïne/usage thérapeutique , Folliculite/immunologie , Folliculite/microbiologie , Infections bactériennes à Gram négatif/complications , Humains
14.
Neuro Endocrinol Lett ; 23 Suppl 2: 48-51, 2002 Jul.
Article de Anglais | MEDLINE | ID: mdl-12163848

RÉSUMÉ

The skin is the most common site of malignancy. Due to several mostly unknown factors, the frequency of skin tumors is increasing. Except for malignant melanoma, reliable statistical data on the frequency of skin tumors are scarce. Discussion on the epidemiology of skin tumors may take different aspects and factors into consideration: (1) histogenetic type; (2) race, (3) sex; (4) age, (5) localization; (6) environment. Moreover, precancerous conditions also may play an important role in this context. Epithelial tumors, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the most frequent tumors of the skin. Figures show a wide range between 40 and over 700 or 5 and 250 respectively per 100 000 inhabitants per year depending on the country or area of report. Malignant melanoma is more frequently seen in Caucasians living in sunny regions (40) than in northern countries or in dark skinned races (4-12 per 100 000 per year), representing 4% of all skin tumors, but being responsible for 79% of skin cancer deaths. Other types of skin tumors like cutaneous lymphoma, Kaposi sarcoma, lipomas, adnexal tumors etc. are either not reported regularly and reliable epidemiologic data is not available, or are rare cutaneous tumors (taken all together < 1%).


Sujet(s)
Mélanome/épidémiologie , Tumeurs cutanées/épidémiologie , Maladie de Bowen/épidémiologie , Humains , Tumeurs basocellulaires/épidémiologie , Tumeurs épidermoïdes/épidémiologie
15.
Recent Results Cancer Res ; 160: 100-10, 2002.
Article de Anglais | MEDLINE | ID: mdl-12079204

RÉSUMÉ

Acquired melanocytic nevi may show signs of histological dysplasia, and epidemiological studies have demonstrated that dysplastic melanocytic nevi (DMN) are associated with an elevated melanoma risk. Nevertheless, the concept of DMN as precursors of melanoma has remained a concept, in view of the difficulty of establishing unambiguous cytological and histological criteria for DMN. Recent molecular data suggest that genetic instability is more frequent in DMN than in benign acquired melanocytic nevi. We have analyzed 54 benign melanocytic nevi and 6 DMN for loss of heterozygosity (LOH) at microsatellite markers D9S171, IFNA, D9S270, D9S265. LOH at one or more loci was detected in 17 out of 54 benign nevi and in 4 out of 6 DMN. LOH was demonstrated at 26 out of 103 amplified and informative microsatellites in benign nevi and at 6 out of 11 microsatellites in DMN. In addition, 6 benign nevi and 6 DMN were microdissected in 4-15 regions per lesion and analyzed for LOH and microsatellite instability (MSI) at D9S162 and D14S53. Both LOH and MSI were detected more frequently in dysplastic nevi (LOH frequency 0.61 vs 0.18; MSI frequency 0.27 vs 0.05). These results confirm that genetic instability is more prevalent in DMN than in benign acquired melanocytic nevi. Therefore, DMN might be defined as a monoclonal and genetically unstable, but limited, melanocytic proliferation that distinguishes this entity from the benign nevus and from malignant melanoma.


Sujet(s)
Syndrome du naevus dysplasique/génétique , Perte d'hétérozygotie , Répétitions microsatellites/génétique , Naevus pigmentaire/génétique , Chromosomes humains de la paire 9 , ADN tumoral/génétique , Humains , Réaction de polymérisation en chaîne
16.
Recent Results Cancer Res ; 160: 271-80, 2002.
Article de Anglais | MEDLINE | ID: mdl-12079224

RÉSUMÉ

Mycosis fungoides is a clinicopathologic term which describes a neoplasm of cerebriform T lymphocytes that form plaques and tumors. We further suggest that mycosis fungoides arises in a background of chronic inflammation or as a response to chronic antigenic stimulation. Subsequently, a series of mutations results in the stepwise progression from eczematous patches, to plaques, tumors and eventual hematogenous dissemination. The pathogenetic process is driven by various, probably individually different, exogenous factors, e.g. environmental foreign antigens, bacterial superantigen, and/or endogenous factors, e.g. autocrine cytokine loops, CD40/CD40L and B7/CD28 interaction.


Sujet(s)
Inflammation/anatomopathologie , Lymphome T/anatomopathologie , Tumeurs cutanées/anatomopathologie , Humains
17.
Int J Cancer ; 99(1): 82-7, 2002 May 01.
Article de Anglais | MEDLINE | ID: mdl-11948496

RÉSUMÉ

Expression of human leucocyte antigen (HLA) Class I molecules is essential for the recognition of malignant melanoma (MM) cells by CD8(+) T lymphocytes. A complete or partial loss of HLA Class I molecules is a potent strategy for MM cells to escape from immunosurveillance. In 2 out of 55 melanoma cell cultures we identified a complete phenotypic loss of HLA allospecificities. Both patients have been treated unsuccessfully with HLA-A2 peptides. To identify the reasons underlying the loss of single HLA-A allospecificities, we searched for genomic alterations at the locus for HLA Class I alpha-chain on chromosome 6 in melanoma cell cultures established from 2 selected patients with MM in advanced stage. This deficiency was associated with alterations of HLA-A2 gene sequences as determined by polymerase chain reaction-sequence specific primers (PCR-SSP). Karyotyping revealed a chromosomal loss in Patient 1, whereas melanoma cell cultures established from Patient 2 displayed 2 copies of chromosome 6. Loss of heterozygosity (LOH) using markers located around position 6p21 was detected in both cases. By applying group-specific primer-mixes spanning the 5'-flanking region of the HLA-A2 gene locus the relevant region was amplified by PCR and subsequent sequencing allowed alignment with the known HLA Class I reference sequences. Functional assays using HLA-A2-restricted cytotoxic T-cell clones were performed in HLA-A2 deficient MM cultures and revealed a drastically reduced susceptibility to CTL lysis in HLA-A2 negative cells. We could document the occurrence of selective HLA-A2 deficiencies in cultured advanced-stage melanoma metastases and identify their molecular causes as genomic alterations within the HLA-A gene locus.


Sujet(s)
Antigènes néoplasiques/génétique , Antigène HLA-A2/génétique , Perte d'hétérozygotie , Mélanome/génétique , Tumeurs cutanées/génétique , Allèles , Chromosomes humains de la paire 6/génétique , Cytométrie en flux , Gènes MHC de classe I/génétique , Humains , Caryotypage , Mélanome/immunologie , Adulte d'âge moyen , Réaction de polymérisation en chaîne , Polymorphisme de conformation simple brin , Analyse de séquence d'ADN , Tumeurs cutanées/immunologie , Lymphocytes T cytotoxiques/immunologie , Cellules cancéreuses en culture
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