In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 31, No. 15_suppl ( 2013-05-20), p. e15513-e15513
Abstract:
e15513 Background: Tyrosine kinase inhibitors (TKI), such as sunitinib, sorafenib and pazopanib, have replaced immunotherapy as the standard of care for metastatic renal cell carcinoma (mRCC). However, their use in sequential or combined strategies is limited by the lack of evidences on TKI-induced cell death in cancer cells. Aim of our study was to evaluate the different mechanisms responsible of the anti-proliferative and cytotoxic effects induced in vitro by µM doses of sunitinib, sorafenib and pazopanib in 5637 and J82 bladder cancer (BC) cell lines. Methods: The viability of BC cell lines were tested by MTT assay. Autophagy was evaluated by western blot analysis with anti-LC3 and anti-p62 antibodies, acridine orange staining and cytofluorimetric analysis. Necrotic cell death was evaluated by Annexin-V/PI staining and FACS analysis. The cathepsin B activation was evaluated by western blot using an anti-cathepsin B antibody; the cathepsin B proteolytic activity was determined using the fluorogenic Z-Arg-Arg-AMC peptide and the fluorescence of the hydrolyzed 7-amino-4-methyl-coumarin was detected by a SpectraMax Gemini XPS microplate reader. Results: We found that sunitinib and pazopanib markedly reduced at mM dose the viability of BC cells. Treatment for 24h with 20µM of sunitinib, by triggering “Incomplete autophagy”, induced necrosis of BC cells. In addition, sunitinib as a lysosomotropic agent, entered free within the lysosomes, where by increasing lysosomal pH and impairing cathepsin B activity, induced lysosomal-dependent necrosis. By contrast, treatment of BC cells for 72h with 20µM of pazopanib induced autophagic cell death, which was markedly reversed in a dose-dependent manner by the autophagic inhibitor 3-MA. The pazopanib-induced autophagic cell death was associated with increased procathepsin B cleavage and enhanced cathepsin B activity. Conclusions: Overall, our results show different cathepsin B-dependent cancer cell death mechanisms induced by sunitinib or pazopanib, providing the biological basis for novel molecularly targeted approaches.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2013.31.15_suppl.e15513
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2013
detail.hit.zdb_id:
2005181-5
