Pazopanib and sunitinib trigger autophagic and non-autophagic death of bladder tumour cells

Abstract

Background:Tyrosine kinase inhibitors (TKI) such as sunitinib and pazopanib display their efficacy in a variety of solid tumours. However, their use in therapy is limited by the lack of evidence about the ability to induce cell death in cancer cells. Our aim was to evaluate cytotoxic effects induced by sunitinib and pazopanib in 5637 and J82 bladder cancer cell lines.Methods:Cell viability was tested by MTT assay. Autophagy was evaluated by western blot using anti-LC3 and anti-p62 antibodies, acridine orange staining and FACS analysis. Oxygen radical generation and necrosis were determined by FACS analysis using DCFDA and PI staining. Cathepsin B activation was evaluated by western blot and fluorogenic Z-Arg-Arg-AMC peptide. Finally, gene expression was performed using RT–PCR Profiler array.Results:We found that sunitinib treatment for 24 h triggers incomplete autophagy, impairs cathepsin B activation and stimulates a lysosomal-dependent necrosis. By contrast, treatment for 48 h with pazopanib induces cathepsin B activation and autophagic cell death, markedly reversed by CA074-Me and 3-MA, cathepsin B and autophagic inhibitors, respectively. Finally, pazopanib upregulates the α-glucosidase and downregulates the TP73 mRNA expression.Conclusion:Our results showing distinct cell death mechanisms activated by different TKIs, provide the biological basis for novel molecularly targeted approaches.

Emerging concepts on drug resistance in bladder cancer: Implications for future strategies

“…As for pazopanib, it induced complete autophagy, as evaluated by p62 degradation, increase of LC3-II protein, AVO formation and autophagic flux. Moreover, pazopanib increased pERK1/2 phosphorylation, and the use of MEK1 inhibitor PD98059 reduced pazopanib-induced autophagy [85] (Fig. 2).…”

Autophagy Inhibition Enhances Sunitinib Efficacy in Clear Cell Ovarian Carcinoma

“…There have been conflicting reports of the effect of sunitinib on autophagy, highlighting that sensitivity to sunitinib-induced autophagy as well as autophagy inhibition varies depending on the tumor type (22)(23)(24)(25)(26). In our study, and consistent with these other reports, we found that sunitinib had different effects on autophagy depending on the CCOC cell line tested and on the presence or absence of oxygen.…”

“…Sunitinib however has been shown to induce or block autophagy depending on the cell type (22)(23)(24)(25)(26). To determine the effect of sunitinib on autophagy in CCOC cells, we first examined LC3-II and the autophagy-dependent degradation of p62 following sunitinib treatment.…”

Chloroquine as a promising adjuvant chemotherapy together with sunitinib

“…This may hint to the "cytoprotective adaptive" role of autophagy initiated by cancer cells in response to the cytotoxic stimuli of sunitinib. In this context, several studies described contradictory effects of sunitinib on autophagy [17][18][19][20] . This warrants further investigation to address this discrepancy.…”