TY - JOUR
T1 - Cluster of differentiation 44 promotes osteosarcoma progression in mice lacking the tumor suppressor Merlin
AU - Ma, Junzhi
AU - Klemm, Janina
AU - Gerardo-Ramírez, Monserrat
AU - Frappart, Lucien
AU - Castven, Darko
AU - Becker, Diana
AU - Zoch, Ansgar
AU - Parent, Romain
AU - Bartosch, Birke
AU - Minnich, Kerstin
AU - Giovannini, Marco
AU - Danckwardt, Sven
AU - Hartmann, Nils
AU - Morrison, Helen
AU - Herrlich, Peter
AU - Marquardt, Jens U.
AU - Hartmann, Monika
N1 - Funding Information:
Sorting of cells on FACSAria was done by Flow Cytometry Core Facility at IMB, Mainz. Plasmid (pUB6/V5-His A, Invitrogen) encoding firefly luciferase gene was kindly provided by Dr Dennis Strand (University Medical Center of the Johannes Gutenberg University, Mainz, Germany). Plasmids for viral transduction were a gift from Dr Yan Cui. We also thank Monika Herr, Carolin Brandscheid, Birgit Pavelka and Silke Schulz for their excellent technical support and Johannes Peter for help with quantitative RT-PCR. Our study was supported by the Bundesministerium f?r Bildung und Forschung (BMBF, 01EO1003 to S. D.), Deutsche Forschungsgemeinschaft (HA 7860/1-1 to M. H., He551 to P. H., INST 371/33-1 and DA89/2-1 to S. D., MA 4443/2-2 to J. U. M. and MO 1421/5-1 to H. M.), Jung-Stiftung f?r Wissenschaft und Forschung (to P. H.) and Volkswagen Foundation Lichtenberg program (to J. U. M.).
Publisher Copyright:
© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/11/1
Y1 - 2020/11/1
N2 - Merlin is a versatile tumor suppressor protein encoded by the NF2 gene. Several lines of evidence suggest that Merlin exerts its tumor suppressor activity, at least in part, by forming an inhibitory complex with cluster of differentiation 44 (CD44). Consistently, numerous NF2 mutations in cancer patients are predicted to perturb the interaction of Merlin with CD44. We hypothesized that disruption of the Merlin-CD44 complex through loss of Merlin, unleashes putative tumor- or metastasis-promoting functions of CD44. To evaluate the relevance of the Merlin-CD44 interaction in vivo, we compared tumor growth and progression in Cd44-positive and Cd44-negative Nf2-mutant mice. Heterozygous Nf2-mutant mice were prone to developing highly metastatic osteosarcomas. Importantly, while the absence of the Cd44 gene had no effect on the frequency of primary osteosarcoma development, it strongly diminished osteosarcoma metastasis formation in the Nf2-mutant mice. In vitro assays identified transendothelial migration as the most prominent cellular phenotype dependent on CD44. Adhesion to endothelial cells was blocked by interfering with integrin α4β1 (very late antigen-4, VLA-4) on osteosarcoma cells and CD44 upregulated levels of integrin VLA-4 β1 subunit. Among other putative functions of CD44, which may contribute to the metastatic behavior, the passage through the endothelial cells also appears to be critical in vivo, as CD44 significantly promoted formation of lung metastasis upon intravenous injection of osteosarcoma cells into immunocompromised mice. Altogether, our results strongly suggest that CD44 plays a metastasis-promoting role in the absence of Merlin.
AB - Merlin is a versatile tumor suppressor protein encoded by the NF2 gene. Several lines of evidence suggest that Merlin exerts its tumor suppressor activity, at least in part, by forming an inhibitory complex with cluster of differentiation 44 (CD44). Consistently, numerous NF2 mutations in cancer patients are predicted to perturb the interaction of Merlin with CD44. We hypothesized that disruption of the Merlin-CD44 complex through loss of Merlin, unleashes putative tumor- or metastasis-promoting functions of CD44. To evaluate the relevance of the Merlin-CD44 interaction in vivo, we compared tumor growth and progression in Cd44-positive and Cd44-negative Nf2-mutant mice. Heterozygous Nf2-mutant mice were prone to developing highly metastatic osteosarcomas. Importantly, while the absence of the Cd44 gene had no effect on the frequency of primary osteosarcoma development, it strongly diminished osteosarcoma metastasis formation in the Nf2-mutant mice. In vitro assays identified transendothelial migration as the most prominent cellular phenotype dependent on CD44. Adhesion to endothelial cells was blocked by interfering with integrin α4β1 (very late antigen-4, VLA-4) on osteosarcoma cells and CD44 upregulated levels of integrin VLA-4 β1 subunit. Among other putative functions of CD44, which may contribute to the metastatic behavior, the passage through the endothelial cells also appears to be critical in vivo, as CD44 significantly promoted formation of lung metastasis upon intravenous injection of osteosarcoma cells into immunocompromised mice. Altogether, our results strongly suggest that CD44 plays a metastasis-promoting role in the absence of Merlin.
UR - http://www.scopus.com/inward/record.url?scp=85087305072&partnerID=8YFLogxK
U2 - 10.1002/ijc.33144
DO - 10.1002/ijc.33144
M3 - Journal articles
C2 - 32525563
AN - SCOPUS:85087305072
SN - 0020-7136
VL - 147
SP - 2564
EP - 2577
JO - International Journal of Cancer
JF - International Journal of Cancer
IS - 9
ER -