In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 31, No. 6_suppl ( 2013-02-20), p. 270-270
Abstract:
270 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 the ability of TKIs to induce cell death in cancer cells. Aim of our study was to evaluate the different mechanisms responsible of the 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 the anti-LC3 and anti-p62 antibodies, acridine orange staining and cytofluorimetric analysis. Necrosis and apoptosis, (ΔΨ m ) dissipation and ROS generation were determined by Annexin-V/PI, JC-1 and DCFDA staining, respectively and cytofluorimetric analysis. The cathepsin B activity was evaluated by ELISA. Finally, by mRNA estraction and RT-PCR array the pazopanib-induced gene profile expression was evaluated. Results: We found that treatment of 5637 and J82 BC cells with the three TKI agents markedly reduced cell viability. Treatment for 24 h with sunitinib and sorafenib at 20 µM dose, triggers an incomplete autophagy of BC cells. In addition, inhibition of autophagy induced by sunitinib and sorafenib triggers cell death of BC cells. Thus, sunitinib by imparing the cathepsin B activity induces lysosomal-dependent necrosis. Similarly, sorafenib by defective lysosomial degradation triggers ROS- and mitochondrial-dependent apoptosis. As regard to pazopanib, we first demonstrate that treatment of BC cells for 72 hrs (20 µM) induces autophagic Type II cell death, which was markedly reversed in a dose-dependent manner by 3MA and chloroquine autophagic inhibitors. Finally, pazopanib upregulates the mRNA expression of α-glucosidase (GAA) and TP73 belonging to the p53 tumor suppressor genes. Conclusions: Overall, our results showing different TKI-induced cell death mechanisms provide the rationale for the sequential use of these agents and the biological basis for novel molecularly targeted approaches.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2013.31.6_suppl.270
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2013
detail.hit.zdb_id:
2005181-5
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