Study of the impact ot the secretome of fibroblasts in UVB-induced and replicative senescence

  • Coline Lambert

Student thesis: Master typesMaster en sciences biomédicales à finalité spécialisée en recherche préclinique


Background: Chronic exposure to UV rays has been reported to be responsible for the development of skin cancers and for skin photoaging. Skin aging is associated to an accumulation of senescent cells. These senescent cells can interact with their microenvironment by secreting multiple factors referred as their senescence-associated secretory phenotype (SASP). This SASP and its impact on the communication between senescent cells and skin cancer cells is the main focus of this work.
Aim: The aim of this work is to study the impact of the secretome isolated from fibroblasts in UVBinduced or in replicative senescence on the migration of melanoma cells and to identify potential protein candidates responsible of this effect.
Methods: UVB-induced and replicative senescence of human dermal fibroblasts were induced by repeated UVB exposures or by several passages in culture. The senescent state was assessed by different biomarkers such as enlarged morphology, SA-βgal, growth arrest, detection of persistent DNA damage, loss of lamin B1 expression and expression of SASP factors. Then the impact of SASP on melanoma cells was analyzed by using migration assays (Boyden chambers). Preliminary studies to assess the protein composition of the
secretome of senescent fibroblasts, as well as the impact of JSH-23 or Navitoclax on the onset of UVBinduced senescence were also achieved.
Results: We developed a new robust model of UVB-induced senescence in normal human dermal fibroblasts. This new model reproducibly induces a senescent phenotype characterized by an enlarged morphology, an increase in the proportion of SA-βgal positive cells, persistent DNA damage and
expression of SASP factors. The conditioned medium harvested from UVB-induced and replicative senescent fibroblasts could not show a clear pro-migration effect on melanoma cells. However, pre-analysis of the secretome by mass spectrometry identified a series of proteins associated with fibroblasts secretion as well as proteins associated to SASP. The results obtained with JSH-23 or Navitoclax were inconclusive due to the high cytotoxicity associated with the treatments.
Conclusion: We have established a robust model of senescence that can now be used to further study the impact of senescent cells conditioned medium on melanoma cells. Furthermore, the technical adjustments for the analysis of the secretome by mass spectrometry have paved the way for further characterization of the composition of the secretome collected from UVB-induced and replicative senescent human dermal fibroblasts. The impact of JSH-23 and Navitoclax on the onset of UVB-induced senescence will need further development.
la date de réponse18 janv. 2022
langue originaleAnglais
L'institution diplômante
  • Universite de Namur
SuperviseurFlorence Debacq-Chainiaux (Promoteur)

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