ABCB5(+) mesenchymal stromal cells facilitate complete and durable wound closure in recessive dystrophic epidermolysis bullosa. Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary, rare, devastating and life-threatening skin fragility disorder with a high unmet medical need. In a recent international, single-arm clinical trial, treatment of 16 patients (aged 6-36 years) with three intravenous infusions of 2 × 10 immunomodulatory ABCB5 dermal mesenchymal stromal cells (MSCs)/kg on days 0, 17 and 35 reduced disease activity, itch and pain. A post-hoc analysis was undertaken to assess the potential effects of treatment with ABCB5 MSCs on the overall skin wound healing in patients suffering from RDEB. Documentary photographs of the affected body regions taken on days 0, 17, 35 and at 12
Translational development of ABCB5(+) dermal mesenchymal stem cells for therapeutic induction of angiogenesis in non-healing diabetic foot ulcers. While rapid healing of diabetic foot ulcers (DFUs) is highly desirable to avoid infections, amputations and life-threatening complications, DFUs often respond poorly to standard treatment. GMP-manufactured skin-derived ABCB5 mesenchymal stem cells (MSCs) might provide a new adjunctive DFU treatment, based on their remarkable skin wound homing and engraftment potential, their ability to adaptively respond to inflammatory signals, and their wound healing-promoting efficacy in mouse wound models and human chronic venous ulcers. The angiogenic potential of ABCB5 MSCs was characterized with respect to angiogenic factor expression at the mRNA
Angiogenin Released from ABCB5(+) Stromal Precursors Improves Healing of Diabetic Wounds by Promoting Angiogenesis. Severe angiopathy is a major driver for diabetes-associated secondary complications. Knowledge on the underlying mechanisms essential for advanced therapies to attenuate these pathologies is limited. Injection of ABCB5 stromal precursors at the edge of nonhealing diabetic wounds in a murine db/db model, closely mirroring human type 2 diabetes, profoundly accelerates wound closure. Strikingly, enhanced angiogenesis was substantially enforced by the release of the ribonuclease angiogenin from ABCB5 stromal precursors. This compensates for the profoundly reduced angiogenin expression in nontreated murine chronic diabetic wounds. Silencing of angiogenin in ABCB5 stromal precursors
Clinical trial of ABCB5+ mesenchymal stem cells for recessive dystrophic epidermolysis bullosa. BACKGROUNDRecessive dystrophic epidermolysis bullosa (RDEB) is a rare, devastating, and life-threatening inherited skin fragility disorder that comes about due to a lack of functional type VII collagen, for which no effective therapy exists. ABCB5+ dermal mesenchymal stem cells (ABCB5+ MSCs) possess immunomodulatory, inflammation-dampening, and tissue-healing capacities. In a Col7a1-/- mouse model of RDEB, treatment with ABCB5+ MSCs markedly extended the animals' lifespans.METHODSIn this international, multicentric, single-arm, phase I/IIa clinical trial, 16 patients (aged 4-36 years) enrolled into 4 age cohorts received 3 i.v. infusions of 2 × 106 ABCB5+ MSCs/kg on days 0, 17, and 35. Patients were
A novel spheroid-based co-culture model mimics loss of keratinocyte differentiation, melanoma cell invasion, and drug-induced selection of ABCB5-expressing cells. Different 3D-cell culture approaches with varying degrees of complexity have been developed to serve as melanoma models for drug testing or mechanistic studies. While these 3D-culture initiatives are already often superior to classical and induced apoptosis of external melanoma cells. Remaining intact external melanoma cells showed a significantly increased amount of ABCB5-immunoreactivity. In the present work, a novel, simple spheroid-based melanoma tri-culture model composed of fibroblasts, keratinocytes, and melanoma cells was described. This model mimicked features observed in early melanoma stages, including loss of keratinocyte
Exome sequencing of ABCB5 identifies recurrent melanoma mutations that result in increased proliferative and invasive capacities. ABCB5 is an ABC transporter that was shown to confer low-level multidrug resistance in cancer. In this study, we show that ABCB5 was mutated in 13.75% of the 640 melanoma samples analyzed. Besides nonsense mutations, two mutation hotspots were found in the ABCB5 protein, in the drug-binding pocket and the nucleotide-binding domains. Four mutations, which are representative of the mutation pattern, were selected. ATPase assays showed that these mutations resulted in a decrease in basal ATP hydrolysis by ABCB5. To select informative melanoma cell lines, mutational profiles of the clinical samples were further analyzed. This study showed mutations in the tumor
Differential expression of ABCB5 in BRAF inhibitor-resistant melanoma cell lines. More than 50% of metastatic melanoma patients have a specific mutation in the serine/threonine kinase BRAF. This results in constitutive activation of the RAS-RAF-MEK-ERK-MAP kinase pathway, which causes uncontrolled cell growth. Vemurafenib (PLX4032) is an oral chemotherapeutic agent that targets the specific mutation V600E in the BRAF protein. Initial response rates are high in patients with BRAF mutant melanoma treated with a BRAF inhibitor such as vemurafenib, but resistance nearly always develops and disease progression ensues. There are several different mechanisms by which melanoma develops BRAF inhibitor resistance. One potential component of resistance is increased drug efflux. Overexpressed ABCB5
Establishment of Novel Limbus-Derived, Highly Proliferative ABCG2+/ABCB5+ Limbal Epithelial Stem Cell Cultures Homeostasis and regeneration of corneal epithelia are sustained by limbal epithelial stem cells (LESCs); thus, an LESC deficiency is a major cause of blindness worldwide. Despite the generally promising results of cultivated LESC transplantation, it has been limited by variations in long-term success rates, the use of xenogeneic and undefined culture components, and a scarcity of donor tissues. In this study, we identified the culture conditions required to expand LESCs and established human limbus-derived highly proliferative ABCG2/ABCB5 double-positive LESCs. These LESCs exhibited the LESC marker profile and differentiated into corneal epithelial cells. In addition, cultured
ΔNp73 regulates the expression of the multidrug-resistance genes ABCB1 and ABCB5 in breast cancer and melanoma cells - a short report Multidrug resistance (MDR) is a major cause of treatment failure. In cancer cells, MDR is often caused by an increased efflux of therapeutic drugs mediated by an up-regulation of ATP binding cassette (ABC) transporters. It has previously been shown that oncogenic correlate with a general up-regulation of ABC transporters in breast cancer samples. In addition, we found that exogenous expression of ΔNp73 led to an increase in the expression of ABCB1 and ABCB5 in the breast cancer-derived cell lines tested, while knocking down of ΔNp73 resulted in a reduction in ABCB1 and ABCB5 expression. In addition, we found that ΔNp73 reduction leads to an intracellular retention
Upregulation of cellular glutathione levels in human ABCB5- and murine Abcb5-transfected cells Previously, we have demonstrated that human ABCB5 is a full-sized ATP-binding cassette transporter that shares strong homology with ABCB1/P-glycoprotein. ABCB5-transfected cells showed resistance to taxanes and anthracyclines. Herein, we further screened ABCB5 substrates, and explored the mechanism ABCB5-transfected 293/B5-11 cells and murine Abcb5-transfected 293/mb5-8 cells showed 6.5- and 14-fold higher resistance to BSO than the mock-transfected 293/mock cells, respectively. BSO is an inhibitor of gamma-glutamylcysteine ligase (GCL), which is a key enzyme of glutathione synthesis. 293/B5-11 and 293/mb5-8 cells also showed resistance to methionine sulfoximine, another GCL inhibitor
Allogeneic ABCB5-positive Dermal Mesenchymal Stromal Cells for Treatment of Therapy-resistant CVU (Phase III) The aim of this clinical trial is to investigate the efficacy and safety of allo-APZ2-CVU, administered topically on therapy-resistant non-healing CVUs compared to placebo. This is a pivotal, randomized, placebo-controlled, double-blind, multicenter, international phase III clinical trial to investigate the efficacy and safety of the IMP allo-APZ2-CVU on wound healing in patients with therapy-resistant non-healing CVU. The allogeneic IMP allo-APZ2-CVU contains skin-derived ABCB5-positive dermal mesenchymal stromal cells isolated from skin tissue of healthy donors and stored in a donor cell bank. Patients will be randomized to be treated with allo-APZ2-CVU or placebo. The patients will undergo
ABCB5-targeted chemoresistance reversal inhibits Merkel cell carcinoma growth. Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer with profound but poorly understood resistance to chemotherapy, which poses a significant barrier to clinical MCC treatment. Here we show that ATP-binding cassette member B5 (ABCB5) confers resistance to standard-of-care MCC chemotherapeutic agents and provide proof-of-principle that ABCB5 blockade can inhibit human MCC tumor growth through sensitization to drug-induced cell cytotoxicity. ABCB5 expression was detected in both established MCC lines and clinical MCC specimens at levels significantly higher than those in normal skin. Carboplatin- and etoposide-resistant MCC cell lines exhibited increased expression of ABCB5, along
Expression of SOX10, ABCB5 and CD271 in melanocytic lesions and correlation with survival data of patients with melanoma. In malignant melanoma (MM), the proteins SOX10, ABCB5 and CD271 are strongly expressed, and are associated with tumour-initiating potential and stem cell-like properties. To compare SOX10, ABCB5 and CD271 expression profiles in melanocytic naevi and MM at different stages , and to correlate these with survival data. Immunohistochemistry was performed for SOX10, ABCB5 and CD271 expression in common naevi (n = 14), dysplastic naevi (n = 11), primary MM (n = 39), lymph node metastases (n = 14) and distant metastases (n = 14). Data were assessed using univariate and multivariate statistics. Compared with melanocytic naevi, there was significantly higher SOX10 expression in primary
Expression of Cell-Surface Marker ABCB5 Causes Characteristic Modifications of Glucose, Amino Acid and Phospholipid Metabolism in the G3361 Melanoma-Initiating Cell Line We present a pilot study aimed at determining the effects of expression of ATP-binding cassette member B5 (ABCB5), a previously described marker for melanoma-initiating cells, on cellular metabolism. Metabolic profiles for two groups of human G3361 melanoma cells were compared, i.e. wildtype melanoma cells with intact ABCB5 expression (ABCB5-WT) and corresponding melanoma cell variants with inhibited ABCB5 expression, through shRNA-mediated gene knockdown (ABCB5-KD). A comprehensive metabolomic analysis was performed by using proton and phosphorus NMR spectroscopy of cell extracts to examine water-soluble metabolites
Salmonella VNP20009-mediated RNA interference of ABCB5 moderated chemoresistance of melanoma stem cell and suppressed tumor growth more potently Drug resistance remains an obstacle hindering the success of chemotherapy. Cancer stem cells (CSCs) have been recently found to confer resistance to chemotherapy. Therefore functional markers of CSCs should be discovered and specific therapies targeting these cells should be developed. In our investigation, a small population of B16F10 cells which was positive for ATP-binding cassette sub-family B member 5 (ABCB5) was isolated. This population displayed characteristics similar to those of CSCs and ABCB5 was identified to confer tumor growth and drug resistance in B16F10 cell line. Although targeting ABCB5 by small short interfering RNA delivered
Elevated expression of ABCB5 in ocular surface squamous neoplasia ATP-binding cassette subfamily B member 5 (ABCB5) is a new member of the ATP-binding cassette superfamily and has been reported as a novel marker for limbal stem cell (LSC), which is essential for corneal homeostasis. ABCB5 expression has also been discovered in the subpopulation of several cancer cells containing the cancer stem cell (CSC). However, the pathogenetic relationship between LSC and CSC and ABCB5 in the ocular surface squamous neoplasm (OSSN) is still entirely unknown. To improve understanding of the role of ABCB5 in OSSN, we performed immunohistochemistry for ABCB5 in nine OSSN case series. While expression of ABCB5 is restricted to the basal epithelial cell layer in the normal limbus, elevated expressions
The role of abcb5 alleles in susceptibility to haloperidol-induced toxicity in mice and humans. We know very little about the genetic factors affecting susceptibility to drug-induced central nervous system (CNS) toxicities, and this has limited our ability to optimally utilize existing drugs or to develop new drugs for CNS disorders. For example, haloperidol is a potent dopamine antagonist susceptible to HIT. Therefore, we genetically analyzed this murine model and performed a translational human genetic association study. A whole genome SNP database and computational genetic mapping were used to analyze the murine genetic model of HIT. Guided by the mouse genetic analysis, we demonstrate that genetic variation within an ABC-drug efflux transporter (Abcb5) affected susceptibility to HIT
Expression of Multidrug Resistance Transporter ABCB5 in a Murine Model of Human Conjunctival Melanoma Conjunctival melanoma (CM) is a rare ocular malignancy with a high tendency to reoccur locally and with a high risk of metastatic disease. Metastases are often unresponsive to conventional treatment. Recently, an animal model was set up using human CM cells. Orthotopic xenografts from human CM cells are linked to tumor recurrences, we used this new murine model to determine the expression of the stem cell marker ABCB5 during tumor progression. Expression of the ABCB5 protein was determined in three cell lines and during different stages of tumor development as observed in our model. All three cell lines contained a subpopulation of cells positive for ABCB5. During tumor development
Allogeneic ABCB5-positive Dermal Mesenchymal Stromal Cells for Treatment of Epidermolysis Bullosa (Phase III) The aim of this clinical trial is to investigate the safety and efficacy of allo-APZ2-OTS administered intravenously to subjects with recessive dystrophic epidermolysis bullosa (RDEB) compared to placebo. undefined
ABCB5 is a limbal stem cell gene required for corneal development and repair Corneal epithelial homeostasis and regeneration are sustained by limbal stem cells (LSCs), and LSC deficiency is a major cause of blindness worldwide. Transplantation is often the only therapeutic option available to patients with LSC deficiency. However, while transplant success depends foremost on LSC frequency within grafts, a gene allowing for prospective LSC enrichment has not been identified so far. Here we show that ATP-binding cassette, sub-family B, member 5 (ABCB5) marks LSCs and is required for LSC maintenance, corneal development and repair. Furthermore, we demonstrate that prospectively isolated human or murine ABCB5-positive LSCs possess the exclusive capacity to fully restore the cornea upon grafting