title: Targeted Inhibition of Phosphoinositide 3-Kinase/Mammalian Target of Rapamycin Sensitizes Pancreatic Cancer Cells to Doxorubicin without Exacerbating Cardiac Toxicity.
abstract: Pancreatic cancer has the lowest 5-year survival rate of all major cancers despite decades of effort to design and implement novel, more effective treatment options. In this study, we tested whether the dual phosphoinositide 3-kinase/mechanistic target of rapamycin inhibitor BEZ235 (BEZ) potentiates the antitumor effects of doxorubicin (DOX) against pancreatic cancer. Cotreatment of BEZ235 with DOX resulted in dose-dependent inhibition of the phosphoinositide 3-kinase/mechanistic target of rapamycin survival pathway, which corresponded with an increase in poly ADP ribose polymerase cleavage. Moreover, BEZ cotreatment significantly improved the effects of DOX toward both cell viability and cell death in part through reduced Bcl-2 expression and increased expression of the shorter, more cytotoxic forms of BIM. BEZ also facilitated intracellular accumulation of DOX, which led to enhanced DNA damage and reactive oxygen species generation. Furthermore, BEZ in combination with gemcitabine reduced MiaPaca2 cell proliferation but failed to increase reactive oxygen species generation or BIM expression, resulting in reduced necrosis and apoptosis. Treatment with BEZ and DOX in mice bearing tumor xenographs significantly repressed tumor growth as compared with BEZ, DOX, or gemcitabine. Additionally, in contrast to the enhanced expression seen in MiaPaca2 cells, BEZ and DOX cotreatment reduced BIM expression in H9C2 cardiomyocytes. Also, the Bcl-2/Bax ratio was increased, which was associated with a reduction in cell death. In vivo echocardiography showed decreased cardiac function with DOX treatment, which was not improved by combination treatment with BEZ. Thus, we propose that combining BEZ with DOX would be a better option for patients than current standard of care by providing a more effective tumor response without the associated increase in toxicity.
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia.
authors.forename: David E
authors.initials: DE
authors.lastname: Durrant
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia.
authors.forename: Anindita
authors.initials: A
authors.lastname: Das
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia.
authors.forename: Samya
authors.initials: S
authors.lastname: Dyer
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia.
authors.forename: Seyedmehrad
authors.initials: S
authors.lastname: Tavallai
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia.
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
authors.affiliation: Department of Biochemistry and Molecular Biology (D.E.D., S.T., P.D.), Department of Internal Medicine, Division of Cardiology, Pauley Heart Center (A.D., S.D., R.C.K.), and Department of Physiology and Biophysics (R.C.K.), Virginia Commonwealth University Medical Center, Richmond, Virginia rakesh@vcu.edu.
authors.forename: Rakesh C
authors.initials: RC
authors.lastname: Kukreja
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000009:adverse effects* / Q000494:pharmacology; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D066126:Cardiotoxicity; D002470:Cell Survival; D004317:Doxorubicin / Q000009:adverse effects / Q000494:pharmacology*; D004357:Drug Synergism; D005260:Female; D045325:HCT116 Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology* / Q000627:therapeutic use; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D032383:Myocytes, Cardiac / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000903:Antibiotics, Antineoplastic; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D004317:Doxorubicin; D007093:Imidazoles; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D011804:Quinolines; D017382:Reactive Oxygen Species; D058570:TOR Serine-Threonine Kinases; C000606775:BCL2L11 protein, human; C000606776:Bcl2l11 protein, mouse; C531198:dactolisib