Banca de QUALIFICAÇÃO: LETÍCIA SILVA FERRAZ
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : LETÍCIA SILVA FERRAZ
DATA : 01/07/2019
HORA: 14:00
LOCAL: Campus Santo André
TÍTULO:
MITOCHONDRIAIS MORPHOLOGY AND DYNAMIC CHANGES IN MELANOMA: COMPREHENSION OF TUMOR BIOLOGY AND PROSPECTION OF NEW THERAPEUTIC TARGETS
PÁGINAS: 111
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
SUBÁREA: Metabolismo e Bioenergética
RESUMO:
Melanoma is a malignant proliferative disease originated in melanocytes characterized byhigh metastatic activity and mortality. This disease is characterized by the BRAF mutation in 40-50 % of cases and NRAS mutation in 15-20 % of cases. Vemurafenib is a MAP kinase pathway inhibitor that prolongs the survival of patients with non-operable metastatic melanoma or BRAFV600E mutation. Recent studies suggested mitochondria as a target of vemurafenib; however, the underlying mechanisms are unclear. Mitochondria are highly dynamic organellesthat constantly fuse and divide, which help the mitochondrial network to adapt to alterations in metabolic cell needs. Dynamin-related GTPases (mitofusin-1, mitofusin-2, and OPA1) are required for mitochondrial fusion, while DRP1 is required by fission. This study aimed to characterize the alterations in mitochondrial dynamics in vemurafenib-treated melanoma cell lines with BRAFV600E (SKmel19) and NRASQ6IR (SKmel147) mutations. For this, cell viability analyzes were performed (MTT reduction test, Trypan blue exclusion and double labeling with annexin V-FITC / propidium iodide); the expression of proteins involved (western blotting); parameters related to mitochondrial function (ATP production and membrane potential), and mitochondrial morphology (transmission electron microscopy and fluorescence). Vemurafenib induced a concentration-dependent and time-dependent cell death in SKmel19 but not in SKmel147 cells. Our analyzes showed that inhibition of the MAPK pathway by vemurafenib in the SKmel19 line promoted the inhibition of DRP1 phosphorylation with maintenance of mitochondrial membrane potential and ATP production. We also found alterations in the expression of proteins involved in the mitochondrial fusion process (Mfn1, Mfn2, OPA-1) in the SKmel19 cell lines. Our data show, in both cell lines, changes in mitochondrial organization pattern, previously fragmented to hyperfused, with the formation of large mitochondrial networks. The mitochondrial fusion induced by vemurafenib in melanoma cells and the impact of this change on mitochondrial energy and cell fate are under investigation. These data evidence the mitochondrial fusion process as a possible therapeutic target for melanoma treatment.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1674592 - TIAGO RODRIGUES
Membro Titular - Examinador(a) Interno ao Programa - 1948411 - LUIZ ROBERTO NUNES
Membro Titular - Examinador(a) Interno ao Programa - 1623562 - RODRIGO LUIZ OLIVEIRA RODRIGUES CUNHA
Membro Suplente - Examinador(a) Externo ao Programa - 1771857 - CARLOS ALBERTO DA SILVA