title: Autophagy is associated with chemoresistance in neuroblastoma.
abstract: Neuroblastoma (NB) is a frequent pediatric tumor characterized by a poor prognosis where a majority of tumors progress despite intensive multimodality treatments. Autophagy, a self-degradative process in cells, could be induced by chemotherapy and be associated with chemoresistance. The aim of this study was to determine whether: 1) autophagy is present in NB, 2) chemotherapy modified its levels, and 3) its inhibition decreased chemoresistance.
  
  
  
  Immunohistochemical stainings were performed on samples from 184 NB patients in order to verify the expression of LC3B, a specific marker for autophagy, and Beclin 1, a positive regulator of autophagy. In addition, we performed an in vitro study with six NB cell lines and six drugs (vincristine, doxorubicin, cisplatin temozolomide, LY294002 and syrolimus). Inhibition of autophagy was performed using ATG5 knockdown cells or hydroxychloroquine (HCQ). Cell survival was measured using the MTT cell proliferation assay. Autophagy was detected by monodansylcadaverine, confocal microscopy and Western blot. In vivo study with tumor xenografts in NSG mice was performed.
  
  
  
  Our results have indicated that autophagy was present at low levels in NB and was not a prognostic factor, while Beclin 1 was highly expressed in children with poor NB prognosis. However, autophagy levels increased after chemotherapy in vitro and in vivo. Tumor progression was significantly decreased in mice treated with a combination of HCQ and vincristine.
  
  
  
  Taken together, autophagy is present in NB, induced by chemotherapy and associated with chemoresistance, which is significantly reduced by its inhibition. Therefore, targeting autophagy represents a very attractive approach to develop new therapeutic strategies in NB.
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.|Department of pathology and cellular biology, Université de Montréal, Montreal, QC, Canada.
authors.forename: Assila
authors.initials: A
authors.lastname: Belounis
authors.affiliation: Department of biochemistry, CHU Sainte Justine, Montreal, QC, Canada.
authors.forename: Carine
authors.initials: C
authors.lastname: Nyalendo
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.
authors.forename: Roxane
authors.initials: R
authors.lastname: Le Gall
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.
authors.forename: Tina V
authors.initials: TV
authors.lastname: Imbriglio
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mahma
authors.affiliation: Division of paediatric oncology, CHU Sainte Justine, Montreal, QC, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Teira
authors.affiliation: Department of surgery, CHU Sainte Justine, 3175, Montreal, QC, Canada.
authors.forename: Mona
authors.initials: M
authors.lastname: Beaunoyer
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.
authors.forename: Sonia
authors.initials: S
authors.lastname: Cournoyer
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada.
authors.forename: Elie
authors.initials: E
authors.lastname: Haddad
authors.affiliation: Department of paediatric oncology, Institut Gustave Roussy, Villejuif, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Vassal
authors.affiliation: Research centre of the Sainte Justine university hospital, Montreal, QC, Canada. hsartelet@chu-grenoble.fr.|Department of pathology and cellular biology, Université de Montréal, Montreal, QC, Canada. hsartelet@chu-grenoble.fr.|Department of pathology and cytogenetic, CHU Sainte Justine, Montreal, QC, Canada. hsartelet@chu-grenoble.fr.
authors.forename: Hervé
authors.initials: H
authors.lastname: Sartelet
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics*; D000071187:Autophagy-Related Protein 5 / Q000235:genetics / Q000378:metabolism; D015415:Biomarkers; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D004195:Disease Models, Animal; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005500:Follow-Up Studies; D055786:Gene Knockout Techniques; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D051379:Mice; D018345:Mice, Knockout; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D000071187:Autophagy-Related Protein 5; D015415:Biomarkers; D034741:RNA, Small Interfering
keywords: Autophagy; Chemoresistance; Hydroxychloroquine; Neuroblastoma