"
HIV protease-induced
lipodystrophy syndrome" is associated with the use of
HIV protease inhibitors for treatment of
HIV infection. In-vitro studies suggest that alteration of
sterol regulatory
element binding protein-1 levels underlie its pathogenesis. We postulated that
HIV protease inhibitors may represent a novel class of antiliposarcoma agents. SW872, FU-DDLS-1 and LiSa-2
liposarcoma, and HT1080 and 293 nonliposarcoma cell lines were treated with
HIV protease inhibitors (
nelfinavir,
ritonavir,
saquinavir,
indinavir and
amprenavir), and clonogenic assays were performed.
Nelfinavir exhibited the most potent inhibition of clonogenicity, and further assays for proliferation, cell cycle and apoptosis were performed with
nelfinavir. Immunoblots were performed for
sterol regulatory
element binding protein-1, proapoptotic and cell cycle-related
protein expression after
nelfinavir treatment. Finally, a
sterol regulatory
element binding protein-1-inducible SW872 cell line was developed to examine the phenotype resulting from upregulated
sterol regulatory
element binding protein-1.
Nelfinavir selectively inhibited clonogenicity and proliferation, and induced G1 cell cycle block and induced apoptosis in a dose-dependent manner in SW872 and LiSa-2 cells, whereas it had minimal or no effect on these parameters in FU-DDLS-1 or nonliposarcoma cells.
Nelfinavir induced significant
sterol regulatory
element binding protein-1 expression in a dose-dependent and time-dependent fashion in sensitive SW872 and LiSa-2 cells, modestly in HT1080 cells, but not in
nelfinavir-insensitive FU-DDLS-1 and 293 cells without inducing adipocytic differentiation. Forced expression of
sterol regulatory
element binding protein-1 in inducible-SW872 cells led to the induction of proapoptotic and antiproliferative
proteins, and consequent reduction of cellular proliferation. Our data indicate that
nelfinavir represents a novel class of antiliposarcoma agent that acts by selectively upregulating
sterol regulatory
element binding protein-1 expression in
liposarcomas.