title: Antagonistic effects of chloroquine on autophagy occurrence potentiate the anticancer effects of everolimus on renal cancer cells.
abstract: Renal cell carcinoma is an aggressive disease often asymptomatic and weakly chemo-radiosensitive. Currently, new biologic drugs are used among which everolimus, an mTOR inhibitor, that has been approved for second-line therapy. Since mTOR is involved in the control of autophagy, its antitumor capacity is often limited. In this view, chloroquine, a 4-alkylamino substituted quinoline family member, is an autophagy inhibitor that blocks the fusion of autophagosomes and lysosomes. In the present study, we evaluated the effects of everolimus alone or in combination with chloroquine on renal cancer cell viability and verified possible synergism. Our results demonstrate that renal cancer cells are differently sensitive to everolimus and chloroquine and the pharmacological combination everolimus/chloroquine was strongly synergistic inducing cell viability inhibition. In details, the pharmacological synergism occurs when chloroquine is administered before everolimus. In addition, we found a flow autophagic block and shift of death mechanisms to apoptosis. This event was associated with decrease of Beclin-1/Bcl(-)2 complex and parallel reduction of anti-apoptotic protein Bcl(-)2 in combined treatment. At last, we found that the enhancement of apoptosis induced by drug combination occurs through the intrinsic mitochondrial apoptotic pathway activation, while the extrinsic pathway is involved only partly following its activation by chloroquine. These results provide the basis for new therapeutic strategies for the treatment of renal cell carcinoma after appropriate clinical trial.
authors: a Department of Biochemistry; Biophysics and General Pathology.
authors: A
authors: A
authors: Grimaldi
authors: D
authors: D
authors: Santini
authors: S
authors: S
authors: Zappavigna
authors: A
authors: A
authors: Lombardi
authors: G
authors: G
authors: Misso
authors: M
authors: M
authors: Boccellino
authors: V
authors: V
authors: Desiderio
authors: P P
authors: PP
authors: Vitiello
authors: G
authors: G
authors: Di Lorenzo
authors: A
authors: A
authors: Zoccoli
authors: F
authors: F
authors: Pantano
authors: M
authors: M
authors: Caraglia
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D002292:Carcinoma, Renal Cell / Q000188:drug therapy* / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002738:Chloroquine / Q000494:pharmacology*; D004357:Drug Synergism; D000068338:Everolimus / Q000494:pharmacology*; D006801:Humans; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000235:genetics; D008247:Lysosomes / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D008565:Membrane Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D002738:Chloroquine; D000068338:Everolimus; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases
keywords: AVOS, autophagic vacuoles; CLC, chloroquine; FITC, fluorescein isothiocyanate; MDC monodansyl-cadaverine; MFI, mean fluorescence intensity; PI, propidium iodide; RAD, everolimus; VHL, Von Hippel-Lindau; apoptosis; autophagy; chloroquine; everolimus; renal cancer cells