The HIV protease inhibitor saquinavir induces endoplasmic reticulum stress, autophagy, and apoptosis in ovarian cancer cells.
OBJECTIVE
HIV patients taking antiretroviral protease inhibitors have a lower incidence of infection-associated malignancies, leading to the hypothesis that these drugs have antineoplastic activity. Given the need for novel treatment approaches in ovarian cancer, we sought to determine whether the protease inhibitor saquinavir has antineoplastic activity in ovarian cancer cell lines, and to elucidate the mechanism through which this occurs.


METHODS
A panel of ovarian cancer cell lines was treated with saquinavir. The effect of saquinavir on cell growth, viability, apoptotic and non-apoptotic cell death was determined. Stimulation of endoplasmic reticulum stress (ERS) response was assessed by immunoblotting for ERS regulators GRP78 and ATF6. Induction of autophagy was assessed using transmission electron microscopy (TEM), and confocal microscopy was performed to demonstrate changes in green fluorescent protein-labeled LC3 expression patterns.


RESULTS
Saquinavir induced cell death in chemosensitive and chemoresistant ovarian cancer cells in a time- and dose-dependent manner. Saquinavir treatment resulted in caspase-dependent apoptosis and caspase-independent cell death characterized by induction of ERS and autophagy. Cellular morphology assessed by TEM revealed apoptotic, autophagic, and necrotic cell death.


CONCLUSIONS
Saquinavir is an FDA-approved agent for the treatment of HIV, and our data suggest that it may also have clinical application in the treatment of ovarian cancer. Saquinavir induces endoplasmic reticulum stress, autophagy, and apoptosis in ovarian cancer cells. Given the challenges of chemoresistance in ovarian cancer, saquinavir may have particular benefit in the treatment of chemoresistant tumors that may respond to the induction of caspase-independent cell death by mechanisms such as autophagy.
McLean
Karen
K
Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA.
VanDeVen
Natalie A
NA
Sorenson
Dorothy R
DR
Daudi
Sayeema
S
Liu
J Rebecca
JR
D000255:Adenosine Triphosphate / Q000378:metabolism; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects; D053453:Caspase 9 / Q000378:metabolism; D061945:Caspase Inhibitors; D045744:Cell Line, Tumor; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004721:Endoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D006801:Humans; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019258:Saquinavir / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D000091342:Endoplasmic Reticulum Chaperone BiP; D017320:HIV Protease Inhibitors; C000717247:HSPA5 protein, human; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D000255:Adenosine Triphosphate; D053453:Caspase 9; D019258:Saquinavir