title: Macroautophagy is dispensable for growth of KRAS mutant tumors and chloroquine efficacy.
abstract: Macroautophagy is a key stress-response pathway that can suppress or promote tumorigenesis depending on the cellular context. Notably, Kirsten rat sarcoma (KRAS)-driven tumors have been reported to rely on macroautophagy for growth and survival, suggesting a potential therapeutic approach of using autophagy inhibitors based on genetic stratification. In this study, we evaluated whether KRAS mutation status can predict the efficacy to macroautophagy inhibition. By profiling 47 cell lines with pharmacological and genetic loss-of-function tools, we were unable to confirm that KRAS-driven tumor lines require macroautophagy for growth. Deletion of autophagy-related 7 (ATG7) by genome editing completely blocked macroautophagy in several tumor lines with oncogenic mutations in KRAS but did not inhibit cell proliferation in vitro or tumorigenesis in vivo. Furthermore, ATG7 knockout did not sensitize cells to irradiation or to several anticancer agents tested. Interestingly, ATG7-deficient and -proficient cells were equally sensitive to the antiproliferative effect of chloroquine, a lysosomotropic agent often used as a pharmacological tool to evaluate the response to macroautophagy inhibition. Moreover, both cell types manifested synergistic growth inhibition when treated with chloroquine plus the tyrosine kinase inhibitors erlotinib or sunitinib, suggesting that the antiproliferative effects of chloroquine are independent of its suppressive actions on autophagy.
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965; christina.eng@pfizer.com beat.nyfeler@novartis.com.
authors.forename: Christina H
authors.initials: CH
authors.lastname: Eng
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Zuncai
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965;
authors.forename: Diane
authors.initials: D
authors.lastname: Tkach
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965;
authors.forename: Lourdes
authors.initials: L
authors.lastname: Toral-Barza
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Savuth
authors.initials: S
authors.lastname: Ugwonali
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Shanming
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Fitzgerald
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Elizabeth
authors.initials: E
authors.lastname: George
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Frias
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Nadire
authors.initials: N
authors.lastname: Cochran
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Rowena
authors.initials: R
authors.lastname: De Jesus
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Gregory
authors.initials: G
authors.lastname: McAllister
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Hoffman
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965;
authors.forename: Kevin
authors.initials: K
authors.lastname: Bray
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965;
authors.forename: LuAnna
authors.initials: L
authors.lastname: Lemon
authors.affiliation: Oncology Research Unit, Pfizer, Pearl River, NY 10965;
authors.forename: Judy
authors.initials: J
authors.lastname: Lucas
authors.affiliation: Oncology Research Unit, Pfizer, San Diego, CA 92121;
authors.forename: Valeria R
authors.initials: VR
authors.lastname: Fantin
authors.affiliation: Oncology Research Unit, Pfizer, San Diego, CA 92121;
authors.forename: Robert T
authors.initials: RT
authors.lastname: Abraham
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, MA 02139;
authors.forename: Leon O
authors.initials: LO
authors.lastname: Murphy
authors.affiliation: Department of Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, CH-4056 Basel, Switzerland christina.eng@pfizer.com beat.nyfeler@novartis.com.
authors.forename: Beat
authors.initials: B
authors.lastname: Nyfeler
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D000071193:Autophagy-Related Protein 7; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000235:genetics / Q000473:pathology; D002738:Chloroquine / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D000069347:Erlotinib Hydrochloride / Q000494:pharmacology; D055786:Gene Knockout Techniques; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D011758:Pyrroles / Q000494:pharmacology; D011836:Radiation Tolerance / Q000235:genetics; D000077210:Sunitinib; D044764:Ubiquitin-Activating Enzymes / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; C117307:KRAS protein, human; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; D002738:Chloroquine; D000069347:Erlotinib Hydrochloride; D016283:Proto-Oncogene Proteins p21(ras); C509349:ATG7 protein, human; D000071193:Autophagy-Related Protein 7; D044764:Ubiquitin-Activating Enzymes; D000077210:Sunitinib
keywords: ATG7; KRAS; autophagy; cancer; chloroquine