title: Targeting HSP70 and GRP78 in canine osteosarcoma cells in combination with doxorubicin chemotherapy.
abstract: Heat shock proteins (HSPs) are molecular chaperones subdivided into several families based on their molecular weight. Due to their cytoprotective roles, these proteins may help protect cancer cells against chemotherapy-induced cell death. Investigation into the biologic activity of HSPs in a variety of cancers including primary bone tumors, such as osteosarcoma (OSA), is of great interest. Both human and canine OSA tumor samples have aberrant production of HSP70. This study assessed the response of canine OSA cells to inhibition of HSP70 and GRP78 by the ATP-mimetic VER-155008 and whether this treatment strategy could sensitize cells to doxorubicin chemotherapy. Single-agent VER-155008 treatment decreased cellular viability and clonogenic survival and increased apoptosis in canine OSA cell lines. However, combination schedules with doxorubicin after pretreatment with VER-155008 did not improve inhibition of cellular viability, apoptosis, or clonogenic survival. Treatment with VER-155008 prior to chemotherapy resulted in an upregulation of target proteins HSP70 and GRP78 in addition to the co-chaperone proteins Herp, C/EBP homologous transcription protein (CHOP), and BAG-1. The increased GRP78 was more cytoplasmic in location compared to untreated cells. Single-agent treatment also revealed a dose-dependent reduction in activated and total Akt. Based on these results, targeting GRP78 and HSP70 may have biologic activity in canine osteosarcoma. Further studies are required to determine if and how this strategy may impact the response of osteosarcoma cells to chemotherapy.
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Asling
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Jodi
authors.initials: J
authors.lastname: Morrison
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada. mutsaers@uoguelph.ca.|Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada. mutsaers@uoguelph.ca.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Mutsaers
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000633:toxicity*; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D004285:Dogs; D004317:Doxorubicin / Q000633:toxicity*; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011684:Purine Nucleosides / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051742:Transcription Factor CHOP / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D056811:Unfolded Protein Response; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000903:Antibiotics, Antineoplastic; C091732:BCL2-associated athanogene 1 protein; D004268:DNA-Binding Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D011684:Purine Nucleosides; D014157:Transcription Factors; C550733:VER 155008; D051742:Transcription Factor CHOP; D004317:Doxorubicin; D051057:Proto-Oncogene Proteins c-akt
keywords: Chemotherapy; Dog; Doxorubicin; Heat shock protein 70 (HSP70); Osteosarcoma