Friedemann Laube1, Dagobert Glanz2. 1. Martin Luther University Halle-Wittenberg, Institute of Physiological Chemistry, Halle, Germany friedemann.laube@medizin.uni-halle.de. 2. Martin Luther University Halle-Wittenberg, Institute of Physiological Chemistry, Halle, Germany.
Abstract
BACKGROUND: The human melanoma cell line IGR-1 was used for the detection and regulation of both melanotransferrin (MTf) and transferrin receptor 1 (TFRC, CD71). While the function in iron transport of the TFRC is well documented the functional importance of MTf is not yet fully understood. Due to the up-regulation of TFRC by hyaluronan (HA) some components and aspects of CD44 signaling were investigated. MATERIALS AND METHODS: The cell-surface proteins MTf, TFRC and ERBB2 receptor tyrosine kinase 2 (ERBB2) were detected by immunoluminescent technique using different polyclonal and monoclonal antibodies. Ionomycin was used to inhibit β-catenin/T-cell-specific transcription factor (TCF) association, essential in HA-CD44-ERBB2 signaling. RESULTS: MTf, was found to be resistant to phosphatidylinositol-specific phospholipase C. However, MTf as well as TFRC were sensitive to partial proteolytic degradation by pronase E and trypsin. The expression of MTf was shown to be up-regulated by mannose-6-phosphate and that of TFRC by HA. Ionomycin at 10 μM inhibited TFRC up-regulation. However, at 50 μM it induced a 7.5-fold increase of TFRC concentration. CONCLUSION: Our results suggest that human melanoma cells are able to up-regulate TFRC expression using HA/CD44 signaling. The whole pathway comprises of the sequence: HA/CD44, neural Wiskott-Aldrich syndrome protein (N-WASP), ERBB2, β-catenin/TCF, c-MYC and TFRC. Since β-catenin is also known to be a component of wingless/Int-1-Frizzled signaling that also leads to transcriptional c-MYC activation, the pathway found here might be alternatively used by melanoma cells for iron supply, necessary for cell proliferation. Copyright
BACKGROUND: The humanmelanoma cell line IGR-1 was used for the detection and regulation of both melanotransferrin (MTf) and transferrin receptor 1 (TFRC, CD71). While the function in iron transport of the TFRC is well documented the functional importance of MTf is not yet fully understood. Due to the up-regulation of TFRC by hyaluronan (HA) some components and aspects of CD44 signaling were investigated. MATERIALS AND METHODS: The cell-surface proteins MTf, TFRC and ERBB2 receptor tyrosine kinase 2 (ERBB2) were detected by immunoluminescent technique using different polyclonal and monoclonal antibodies. Ionomycin was used to inhibit β-catenin/T-cell-specific transcription factor (TCF) association, essential in HA-CD44-ERBB2 signaling. RESULTS:MTf, was found to be resistant to phosphatidylinositol-specific phospholipase C. However, MTf as well as TFRC were sensitive to partial proteolytic degradation by pronase E and trypsin. The expression of MTf was shown to be up-regulated by mannose-6-phosphate and that of TFRC by HA. Ionomycin at 10 μM inhibited TFRC up-regulation. However, at 50 μM it induced a 7.5-fold increase of TFRC concentration. CONCLUSION: Our results suggest that humanmelanoma cells are able to up-regulate TFRC expression using HA/CD44 signaling. The whole pathway comprises of the sequence: HA/CD44, neural Wiskott-Aldrich syndrome protein (N-WASP), ERBB2, β-catenin/TCF, c-MYC and TFRC. Since β-catenin is also known to be a component of wingless/Int-1-Frizzled signaling that also leads to transcriptional c-MYC activation, the pathway found here might be alternatively used by melanoma cells for iron supply, necessary for cell proliferation. Copyright
Authors: K Kobayashi; M Suzukawa; K Watanabe; S Arakawa; S Igarashi; I Asari; A Hebisawa; H Matsui; H Nagai; T Nagase; K Ohta Journal: Clin Exp Immunol Date: 2019-11-08 Impact factor: 4.330
Authors: Tarak Srivastava; Trupti Joshi; Yuexu Jiang; Daniel P Heruth; Mohamed H Rezaiekhaligh; Jan Novak; Vincent S Staggs; Uri S Alon; Robert E Garola; Ashraf El-Meanawy; Ellen T McCarthy; Jianping Zhou; Varun C Boinpelly; Ram Sharma; Virginia J Savin; Mukut Sharma Journal: Am J Physiol Renal Physiol Date: 2020-07-06