Bafilomycin A1 inhibits autophagy and induces apoptosis in MG63 osteosarcoma cells

Xie, Zonggang; Xie, Ye; Xu, Youjia; Zhou, Haibin; Xu, Wei; Dong, Qirong

doi:10.3892/mmr.2014.2281

Cited by 49 publications

(32 citation statements)

References 15 publications

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“…BAF, a known inhibitor of vacuolar H+ ATPase pump (V-ATPase) is used as a control for its known inhibitory effects on autophagy efflux. (15)(16)(17) BAF control alone resulted in significant accumulation of LC3-II and p62 levels in every cell line model, as expected ( Fig.1C-1E). The combination of BAF plus STF did not show an additive effect on LC3-II levels compared to BAF alone in neither VHL-mutated RCC4 cells nor in cell lines containing a functioning gene, RCC4 VHL and HeLa (Fig.…”

Section: Stf-62247 Blocks Late Stages Of Autophagy Independently Of Vsupporting

confidence: 82%

STF-62247 blocks late stages of autophagy by disrupting lysosomal physiology

Bouhamdani

Comeau

Cormier

et al. 2018

Preprint

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STF-62247 was previously identified as a promising compound able to selectively target the loss of the tumor suppressor gene von Hippel-Lindau (VHL) in renal cell carcinomas. This present work investigates the effect of STF-62247 on the autophagic flux. Our investigations show that STF-62247 blocks late stages of autophagy through lysosomal disruption. Indeed, STF-62247 localizes at lysosomes and causes unregulated swelling of these acidic compartments in VHL-mutated cells, linking a potential role for VHL in lysosomal integrity. Knock-outs of BECN1 and ATG5 were able to rescue the viability of VHL-mutated cells in response to STF-62247 but did not rescue the lysosomal swelling. In fact, neutralizing the lysosomal pH by inhibiting the vacuolar H+-ATPase completely rescued this phenotype. Moreover, we show that STF-62247 disrupts endocytic routes and causes cathepsin D trafficking defects. This mechanistic study is the first to characterize STF-62447 as a novel lysosomotropic compound. Importantly, our study re-classifies STF-62247 as a blocker of later stages of autophagy and highlights its potential usage as a powerful new tool for endocytic and autophagy-related research.

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Section: Stf-62247 Blocks Late Stages Of Autophagy Independently Of Vsupporting

confidence: 82%

STF-62247 blocks late stages of autophagy by disrupting lysosomal physiology

Bouhamdani

Comeau

Cormier

et al. 2018

Preprint

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“…Increased autophagy activities have been reported to increase cell growth and promote chemoresistance in osteosarcoma cells [34-36]. In this study, we found decreased p62 expression in osteosarcoma patients with poor response to preoperative chemotherapy.…”

Section: Discussionsupporting

confidence: 61%

Expression and Clinical Implication of Autophagy-Associated Protein p62 in Osteosarcoma

Wang

et al. 2018

Oncology

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Purpose: Recent studies highlight the role of autophagy in cancer tumorigenesis, recurrence, metastasis, and chemoresistance. p62 is an adapter protein that is crucial for the autophagy pathway. In this study, we will describe the expression of p62 and its correlation with clinic prognosis in osteosarcoma. Methods: Western blot was used to test the expression of p62 in osteosarcoma cell lines (U2OS, KHOS, MG63, Saos-2, U2OSR2, KHOSR2, and 143B). A tissue microarray (TMA) was analyzed by immunohistochemistry to determine the expression levels of p62 in osteosarcoma patients and evaluate any correlation between p62 and clinical characteristics in osteosarcoma patients. Results: p62 was expressed differently in all cell lines. The TMA also showed differential expression in osteosarcoma tissues. Seventy-five of 79 (94.9%) patient tissues exhibited p62 immunostaining, ranging from no staining (4 of 97, 5.1%) to 1+ staining (40 of 79, 50.6%), 2+ staining (17 of 79, 21.5%), and 3+ staining (18 of 79, 22.8%). The low staining (1+) was classified as the p62 weak group (50.6%), the medium staining (2+) and intense staining (3+) were classified as the p62 strong group (44.3%). Analyzing the clinical data of the osteosarcoma TMA, we found that the 5-year survival rate of patients with weak p62 expression was significantly lower than that of the patients with strong p62 expression (p = 0.0165). Furthermore, the decreased p62 expression may be associated with higher metastatic and chemoresistant rates in osteosarcoma patients. Conclusion: Our results suggest that p62 may be an effective predictor of prognosis and a potential target for therapy in osteosarcoma.

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“…As deacidification inhibits degradative processes in lysosomes and can both inhibit and enhance autophagy, we wondered whether the large EEA1 structures were created by changes in trafficking to these compartments. In Figure S3, we labeled vehicle or Baf‐treated cells with markers against lysosomes (LAMP1, A–B), Cathepsin D (C–D) or autophagosomes (LC3B, E–F) and observed no overlap between these organelles and the ATP7B clusters.…”

Section: Resultsmentioning

confidence: 99%

Copper Directs ATP7B to the Apical Domain of Hepatic Cells via Basolateral Endosomes

Nyasae¹,

Schell²,

Hubbard³

2014

Traffic

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Physiologic Cu levels regulate the intracellular location of the Cu ATPase ATP7B. Here, we determined the routes of Cu-directed trafficking of endogenous ATP7B in the polarized hepatic cell line WIF-B and in the liver in vivo. Copper (10 μM) caused ATP7B to exit the trans-Golgi network (TGN) in vesicles, which trafficked via large basolateral endosomes to the apical domain within one hour. Although perturbants of luminal acidification had little effect on the TGN localization of ATP7B in low Cu, they blocked delivery to the apical membrane in elevated Cu. If the vesicular proton-pump inhibitor bafilomycin-A1 (Baf) was present with Cu, ATP7B still exited the TGN, but accumulated in large endosomes located near the coverslip, in the basolateral region. Baf washout restored ATP7B trafficking to the apical domain. If ATP7B was staged apically in high Cu, Baf addition promoted the accumulation of ATP7B in subapical endosomes, indicating a blockade of apical recycling, with concomitant loss of ATP7B at the apical membrane. The retrograde pathway to the TGN, induced by Cu removal, was far less affected by Baf than the anterograde (Cu-stimulated) case. Overall, loss of acidification impaired Cu-regulated trafficking of ATP7B at two main sites: 1) sorting and exit from large basolateral endosomes and 2) recycling via endosomes near the apical membrane.

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Bafilomycin A1 inhibits autophagy and induces apoptosis in MG63 osteosarcoma cells

Cited by 49 publications

References 15 publications

STF-62247 blocks late stages of autophagy by disrupting lysosomal physiology

STF-62247 blocks late stages of autophagy by disrupting lysosomal physiology

Expression and Clinical Implication of Autophagy-Associated Protein p62 in Osteosarcoma

Copper Directs ATP7B to the Apical Domain of Hepatic Cells via Basolateral Endosomes

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