Navegando por Palavras-chave "Estresse proteotóxico"

Agora exibindo 1 - 1 de 1
  • Imagem de Miniatura
    Item
    Acesso aberto (Open Access)
    Papel da família da heat shock protein 70 (HSP70) como alvo terapêutico em mieloma múltiplo através de análises in vitro e in vivo
    (Universidade Federal de São Paulo (UNIFESP), 2017-03-07) Eugênio, Angela Isabel Pereira [UNIFESP]; Colleoni, Gisele Wally Braga [UNIFESP]; http://lattes.cnpq.br/2918635854077904; http://lattes.cnpq.br/1240012495336970; Universidade Federal de São Paulo (UNIFESP)
    Introduction: HSP70 has integrative role in protein degradation due to the interaction with many pathways, such as ubiquitin proteasome, unfolded protein response and autophagy. Objectives: To explore the role of HSP70 as a therapeutic target for multiple myeloma (MM) through in vitro and in vivo analyses. Methods: Bioluminescent cell lines RPMI8226-LUC-PURO and U266-LUC-PURO were treated with HSP70 inhibitor (VER155008) and proteasome inhibitor (bortezomib) for evaluation of apoptosis by flow cytometry. HSP70 members, unfolded protein response and autophagy genes were evaluated by qPCR in the same cell lines. Immunodeficient mice were used for subcutaneous xenograft model in two different approaches: RPMI8226-LUC-PURO cells into the right flank to induce a plasmocytoma. When the tumors became palpable mice were randomised to receive bortezomib, VER155008 or bortezomib plus VER155008 or no intervention. Histologic and protein expression analysis were performed. In a second model, each mouse was inoculated at the same moment, with RPMI8226-LUC-PURO cells into the left and U266-LUC-PURO into the righ flank. Mice were randomised into four groups of treatment and received intravenously proteassome and HSP70 inhitors immediately after xenotransplantation of the cell lines. Bioluminescence (BLI) was measured once a day for seven days. Results: RPMI8226- LUC-PURO and U266-LUC-PURO cell lines express HSP70 family genes, XBP-1 and BECLINA-1. Both cell lines treated with bortezomib, VER155008 (50μM and 80μM), isolated or combined, responded with increased expression of HSPA1A/HSPA1B. RPMI8226-LUC-PURO also showed increased expression of HSPA5 and XBP-1 genes after treatment with VER155008 (50μM). RPMI8226-LUC-PURO almost 60% of late apoptosis after treatment with bortezomib (100nM) alone. Treatment with VER155008, isolated or combined with bortezomib, did not add benefit to bortezomib treatment in 128 this cell line. However, U266-LUC-PURO cell line showed over 60% of cell death after treatment with VER155008 (80μM) alone and also with VER155008 (80μM) plus bortezomib, 48 hours after treatmet. In vivo data showed tumor growth reduction by bioluminescence in the group with RPMI8226-LUC-PURO plasmocytoma after treatment with bortezomib, VER155008 or combination of drugs compared to the control group. Nevertheless, the expression of HSP70 proteins, XBP-1s and BECLINA-1 had no statistically significant changes, except for reduction of XBP-1s protein relative expression in to tumors treated with VER155008. For the group of mice that had no prior induction of tumor, treatment with bortezomib, isolated or combined with VER155008 showed inhibition of tumor growth (or incipient growth) assessed by bioluminescence after one week for both cell lines when compared with the control group. Conclusion: Our study shows that the combination of proteasome and HSP70 inhibitors induced cell death in tumor cells in vitro and in vivo (late apoptosis induction and inhibition of tumor growth). Since HSP70 connects multiple signaling pathways that work synergistically to protect tumor cells from death by proteotoxic stress, it can represent a key role to establish a new approach for the treatment of MM (after achievement of the best response or as maintanence therapy) mostly in patients with deletion of 17p (like U266 cell line).