BAG-4/SODD and Associated Antiapoptotic Proteins Are Linked to Aggressiveness of Epithelial Ovarian Cancer ChristinaM.Annunziata, 1 LilachKleinberg, 5 BenDavidson, 5 AasmundBerner, 5 DavidGius, 3 NanaTchabo, 2 SethM.Steinberg, 4 andEliseC.Kohn 1,2 Abstract Purpose: We hypothesized that elevated expression in ovarian cancer of the BAG family of prosurvivalproteinsandassociatedpartnerswouldbeassociatedwithclinicalfeaturesofaggres- sivenessinovariancancer. Experimental Design: Expressionpatterns of BAG-1, BAG-3, BAG-4, and Bcl-xL were determinedby immunohistochemicalanalysis of tissue samples obtained at diagnosis from 28 womenwithstageIIIorstageIVovariancancertreatedwithcisplatin,paclitaxel,andcyclophos- phamideafterinitialcytoreduction.Associationoftheseproteins,BAG-6,heatshockprotein70 (Hsp70),Hsp27,andBcl-2,withclinicalvariableswastestedinovariancancertissuearraysfrom GynecologicOncologyGrouptissuebank. Results: Astatisticallysignificantrelationshipwasfoundbetweenelevatedcytoplasmicexpres- sionofBAG-4andimprovedoverall( P =0.0002)andprogression-freesurvival(P =0.003)in theprospectivelycollectedsamples.Bcl-2stainingwassignificantlymorefrequentonthetissue arrayinlowerstage( P =0.005)andgrade(P =0.0009)tumors,whereasHsp70wasprominent inhighergradecases(P =0.002).Furthermore,Bcl-xLwasmorecloselyassociatedwithserous comparedwithendometrioidovariancancers(P =0.004). Conclusion: Unexpectedly,cytoplasmicexpressionofBAG-4andBcl-2markedlessaggressive ovariancancer,whereasnuclearHsp70suggestedmoreaggressivebehavior.Bcl-xLmayplaya moreprominentfunctioninthepathologyofseroushistologyovariancancerscomparedwiththe endometrioidsubtype.Thefindingspresentedheresupportinvolvementoftheseproteinsinthe propagationofovariancancerandprovideabasisforthedevelopmentofmoleculartherapeutics modulatingthesesurvivalpathways. Ovarian cancer affects over 22,000 women annually, and >70% of these women eventually die of their disease (1). The poor survival of affected women is due in part to three quarters of all patients presenting with advanced stage disease at the time of initial diagnosis (2). Complete response to standard chemotherapy with a taxane and a platinum agent varies from 50% to 85% in advanced disease, depending on the volume of tumor left after cytoreductive surgery (2). Despite this promising initial outcome, these patients have a high cancer- related mortality. New molecular prognostics and therapeutics may identify patients for novel therapies and potentially improve the durability of response. We observed increased expression of the prosurvival protein BAG-3 in platinum- resistant ovarian cancer cells. 6 We therefore sought to deter- mine the expression pattern of the BAG family of proteins and associated partners to discern relationships of these proteins with clinical features of aggressiveness in ovarian cancer. The Bcl-2, BAG, and heat shock protein (Hsp) families of proteins directly interact with each other to regulate cell survival (see diagram in Fig. 1). The Bcl-2 family and associated proteins have been implicated in the pathogenesis of ovarian cancer (3–5). Bcl-xL and Bcl-2 may have prognostic impor- tance in ovarian cancer (6, 7). The BAG proteins act as cochaperones for Bcl-2 and Hsp70 (8, 9). BAG proteins have been shown to bind directly to Bcl-2, but not to Bcl-xL (9). BAG-1, BAG-3, and BAG-4 [also known as silencer of death domain (SODD)] are involved in the survival of cancer cells and have been linked with aggressiveness of breast, gastric, and pancreatic cancer (8–11). Loss of BAG-4, conversely, has been observed in resistance to platinum chemotherapy (7, 12). The BAG proteins have been shown as both cytoplasmic and nuclear in location, although the functional importance of this has not been elucidated (9). Hsp27 and Hsp70 are cocha- perones for the Bcl and BAG proteins and modulate induction 6 N.RasoolandE.C.Kohn,unpublishedobservations. Human Cancer Biology Authors’Affiliations: 1 Medical Oncology Branch, 2 Molecular Signaling Section, LaboratoryofPathology, 3 RadiationOncologyBranch,and 4 BiostatisticsandData ManagementSection,CenterforCancerResearch,NationalCancerInstitute,NIH, Bethesda, Maryland and 5 PathologyClinic,Rikshospitalet-Radiumhospitalet MedicalCenter,Oslo,Norway Received2/7/07;revised7/19/07;accepted8/17/07. Grant support: IntramuralResearchProgramofNIH,NationalCancerInstitute, CenterforCancerResearch. Thecostsofpublicationofthisarticleweredefrayedinpartbythepaymentofpage charges.Thisarticlemustthereforebeherebymarked advertisement inaccordance with18U.S.C.Section1734solelytoindicatethisfact. Requests for reprints: Christina M. Annunziata, Medical Oncology Branch, National Cancer Institute, NIH, Building10, Room 4N115,10 Center Drive, Bethesda,MD20892-1374.Phone:301-402-7259;Fax:301-496-9956;E-mail: annunzic@mail.nih.gov. F 2007AmericanAssociationforCancerResearch. doi:10.1158/1078-0432.CCR-07-0327 www.aacrjournals.org Clin Cancer Res 2007;13(22) November15, 2007 6585 Research. on May 16, 2017. © 2007 American Association for Cancer clincancerres.aacrjournals.org Downloaded from