αvβ3
integrin, a plasma membrane
protein, is amply expressed on an array of
tumors. We identified nuclear αvβ3 pool in
ovarian cancer cells and were interested to explore this phenomenon in two rare and aggressive types of
leukemia, T-cell acute lymphoblastic leukemia (
T-ALL) and
Mast cell leukemia (MCL) using Jurkat and HMC-1 cell lines, respectively. Moreover, we collected primary cells from patients with
chronic lymphocytic leukemia (CLL, n = 11), the most common chronic adult
leukemia and used human lymphoblastoid cell lines (LCL) generated from normal B cells. Nuclear αvβ3
integrin was assessed by Western blots, confocal microscopy, and the ImageStream technology which combines flow-cytometry with microscopy. We further examined post translational modifications (phosphorylation/glycosylation), nuclear trafficking regulation using inhibitors for MAPK (
U0126) and PI3K (
LY294002), as well as nuclear interactions by performing Co-immunoprecipitation (Co-IP). αvβ3
integrin was identified in all cell models within the nucleus and is N-glycosylated. In primary CLL cells the β3
integrin monomer is
tyrosine Y759 phosphorylated, suggesting an active receptor conformation. MAPK and PI3K inhibition in Jurkat and CLL cells led to αvβ3 enhancement in the nucleus and a reduction in the membrane. The nuclear αvβ3
integrin interacts with ERK,
Histone H3 and
Lamin B1 in Jurkat,
Histone H3 in CLL cells, but not in control LCL cells. To conclude, this observational study provides the identification of nuclear αvβ3 in
hematological malignancies and lays the basis for novel
cancer-relevant actions, which may be independent from the membrane functions.