ICAM-2 confers a non-metastatic phenotype in neuroblastoma cells by interaction with α-actinin.
Progressive metastatic disease is a major cause of mortality for patients diagnosed with multiple types of solid tumors. One of the long-term goals of our laboratory is to identify  molecular interactions that regulate metastasis, as a basis for developing agents that inhibit this process. Toward this goal, we recently demonstrated that intercellular adhesion molecule-2 (ICAM-2) converted neuroblastoma (NB) cells from a metastatic to a non-metastatic phenotype, a previously unknown function for ICAM-2. Interestingly, ICAM-2 suppressed metastatic but not tumorigenic potential in preclinical models, supporting a novel mechanism of regulating metastasis. We hypothesized that the effects of ICAM-2 on NB cell phenotype depend on the interaction of ICAM-2 with the cytoskeletal linker protein α-actinin. The goal of the study presented here was to evaluate the impact of α-actinin binding to ICAM-2 on the phenotype of NB tumor cells. We used in silico approaches to examine the likelihood that the cytoplasmic domain of ICAM-2 binds directly to α-actinin. We then expressed variants of ICAM-2 with mutated α-actinin-binding domains, and compared the impact of ICAM-2 and each variant on NB cell adhesion, migration, anchorage-independent growth, co-precipitation with α-actinin and production of localized and disseminated tumors in vivo. The in vitro and in vivo characteristics of cells expressing ICAM-2 variants with modified α-actinin-binding domains differed from cells expressing ICAM-2 wild type (WT) and also from cells that expressed no detectable ICAM-2. Like the WT protein, ICAM-2 variants inhibited cell adhesion, migration and colony growth in vitro. However, unlike the WT protein, ICAM-2 variants did not completely suppress development of disseminated NB tumors in vivo. The data suggest the presence of α-actinin-dependent and α-actinin-independent mechanisms, and indicate that the interaction of ICAM-2 with α-actinin is critical to conferring an ICAM-2-mediated non-metastatic phenotype in NB cells.
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
J M
JM
Feduska
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
S G
SG
Aller
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
P L
PL
Garcia
Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA.
S L
SL
Cramer
Division of Anatomic Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
L N
LN
Council
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
R C A M
RC
van Waardenburg
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
K J
KJ
Yoon
D000199:Actins / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D008958:Models, Molecular; D009154:Mutation; D009362:Neoplasm Metastasis; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D011485:Protein Binding
D000199:Actins; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; C480027:ICAM-2 protein, mouse; C065289:ICAM2 protein, human