The synovial sarcoma SYT-SSX2 oncogene remodels the cytoskeleton through activation of the ephrin pathway.
Synovial sarcoma is a soft tissue cancer associated with a recurrent t(X:18) translocation that generates one of two fusion proteins, SYT-SSX1 or SYT-SSX2. In this study, we demonstrate that SYT-SSX2 is a unique oncogene. Rather than confer enhanced proliferation on its target cells, SYT-SSX2 instead causes a profound alteration of their architecture. This aberrant morphology included elongation of the cell body and formation of neurite-like extensions. We also observed that cells transduced with SYT-SSX2 often repulsed one another. Notably, cell repulsion is a known component of ephrin signaling. Further analysis of SYT-SSX2-infected cells revealed significant increases in the expression and activation of Eph/ephrin pathway components. On blockade of EphB2 signaling SYT-SSX2 infectants demonstrated significant reversion of the aberrant cytoskeletal phenotype. In addition, we discovered, in parallel, that SYT-SSX2 induced stabilization of the microtubule network accompanied by accumulation of detyrosinated Glu tubulin and nocodazole resistance. Glu tubulin regulation was independent of ephrin signaling. The clinical relevance of these studies was confirmed by abundant expression of both EphB2 and Glu tubulin in SYT-SSX2-positive synovial sarcoma tissues. These results indicate that SYT-SSX2 exerts part of its oncogenic effect by altering cytoskeletal architecture in an Eph-dependent manner and cytoskeletal stability through a concurrent and distinct pathway.
Barco
Roy
R
Department of Cancer Biology and Vanderbilt Orthopedic Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Hunt
Laura B
LB
Frump
Andrea L
AL
Garcia
Christina B
CB
Benesh
Andrew
A
Caldwell
Robert L
RL
Eid
Josiane E
JE
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D036342:Ephrins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D051379:Mice; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D041681:NIH 3T3 Cells; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036183:Receptor, EphB2 / Q000378:metabolism; D012190:Retroviridae / Q000187:drug effects; D013584:Sarcoma, Synovial / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D020032:Tyrphostins / Q000494:pharmacology
D036342:Ephrins; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; C116512:SYT-SSX fusion protein; D020032:Tyrphostins; D036183:Receptor, EphB2; C060641:tyrphostin A23