The SH3 domain contributes to BCR/ABL-dependent leukemogenesis in vivo: role in adhesion, invasion, and homing.
To determine the possible role of the BCR/ABL oncoprotein SH3 domain in BCR/ABL-dependent leukemogenesis, we studied the biologic properties of a BCR/ABL SH3 deletion mutant (delta SH3 BCR/ABL) constitutively expressed in murine hematopoietic cells. delta SH3 BCR/ABL was able to activate known BCR/ABL-dependent downstream effector molecules such as RAS, PI-3kinase, MAPK, JNK, MYC, JUN, STATs, and BCL-2. Moreover, expression of delta SH3 BCR/ABL protected 32Dcl3 murine myeloid precursor cells from apoptosis, induced their growth factor-independent proliferation, and resulted in transformation of primary bone marrow cells in vitro. Unexpectedly, leukemic growth from cells expressing delta SH3 BCR/ABL was significantly retarded in SCID mice compared with that of cells expressing the wild-type protein. In vitro and in vivo studies to determine the adhesive and invasive properties of delta SH3 BCR/ABL-expressing cells showed their decreased interaction to collagen IV- and laminin-coated plates and their reduced capacity to invade the stroma and to seed the bone marrow and spleen. The decreased interaction with collagen type IV and laminin was consistent with a reduced expression of alpha 2 integrin by delta SH3 BCR/ABL-transfected 32Dcl3 cells. Moreover, as compared with wild-type BCR/ABL, which localizes primarily in the cytoskeletal/membrane fraction, delta SH3 BCR/ABL was more evenly distributed between the cytoskeleton/membrane and the cytosol compartments. Together, the data indicate that the SH3 domain of BCR/ABL is dispensable for in vitro transformation of hematopoietic cells but is essential for full leukemogenic potential in vivo.
Skorski
T
T
Kimmel Cancer Institute, Jefferson Medical College, Philadelphia, PA 19107, USA.
Nieborowska-Skorska
M
M
Wlodarski
P
P
Wasik
M
M
Trotta
R
R
Kanakaraj
P
P
Salomoni
P
P
Antonyak
M
M
Martinez
R
R
Majewski
M
M
Wong
A
A
Perussia
B
B
Calabretta
B
B
D000818:Animals; D002448:Cell Adhesion / Q000235:genetics; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics*; D002471:Cell Transformation, Neoplastic; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D007942:Leukemia, Experimental / Q000235:genetics / Q000473:pathology*; D051379:Mice; D018909:src Homology Domains / Q000235:genetics*
D016044:Fusion Proteins, bcr-abl