Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib

Megan L. Goodall, Tong Wang, Katie R. Martin, Matthew G. Kortus, Audra L. Kauffman, Jeffrey M. Trent, Stephen Gately, Jeffrey P. MacKeigan

Research output: Contribution to journalArticle

Abstract

Autophagy is a dynamic cell survival mechanism by which a double-membrane vesicle, or autophagosome, sequesters portions of the cytosol for delivery to the lysosome for recycling. This process can be inhibited using the antimalarial agent chloroquine (CQ), which impairs lysosomal function and prevents autophagosome turnover. Despite its activity, CQ is a relatively inadequate inhibitor that requires high concentrations to disrupt autophagy, highlighting the need for improved small molecules. To address this, we screened a panel of antimalarial agents for autophagy inhibition and chemically synthesized a novel series of acridine and tetrahydroacridine derivatives. Structure-activity relationship studies of the acridine ring led to the discovery of VATG-027 as a potent autophagy inhibitor with a high cytotoxicity profile. In contrast, the tetrahydroacridine VATG-032 showed remarkably little cytotoxicity while still maintaining autophagy inhibition activity, suggesting that both compounds act as autophagy inhibitors with differential effects on cell viability. Further, knockdown of autophagy-related genes showed no effect on cell viability, demonstrating that the ability to inhibit autophagy is separate from the compound cytotoxicity profiles. Next, we determined that both inhibitors function through lysosomal deacidification mechanisms and ultimately disrupt autophagosome turnover. To evaluate the genetic context in which these lysosomotropic inhibitors may be effective, they were tested in patient-derived melanoma cell lines driven by oncogenic BRAF (v-raf murine sarcoma viral oncogene homolog B). We discovered that both inhibitors sensitized melanoma cells to the BRAF V600E inhibitor vemurafenib. Overall, these autophagy inhibitors provide a means to effectively block autophagy and have the potential to sensitize mutant BRAF melanomas to first-line therapies.

Original languageEnglish (US)
Pages (from-to)1120-1136
Number of pages17
JournalAutophagy
Volume10
Issue number6
DOIs
StatePublished - 2014
Externally publishedYes

Fingerprint

Autophagy
Melanoma
Neoplasms
Acridines
Cell Survival
Chloroquine
Antimalarials
PLX4032
Recycling
Structure-Activity Relationship
Lysosomes
Oncogenes
Sarcoma
Cytosol
Cell Line
Membranes

Keywords

  • Antimalarial
  • Autophagy
  • Chloroquine
  • Lysosome
  • Melanoma
  • PLX-4032
  • Quinacrine
  • Vemurafenib

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Medicine(all)

Cite this

Goodall, M. L., Wang, T., Martin, K. R., Kortus, M. G., Kauffman, A. L., Trent, J. M., ... MacKeigan, J. P. (2014). Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib. Autophagy, 10(6), 1120-1136. https://doi.org/10.4161/auto.28594

Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib. / Goodall, Megan L.; Wang, Tong; Martin, Katie R.; Kortus, Matthew G.; Kauffman, Audra L.; Trent, Jeffrey M.; Gately, Stephen; MacKeigan, Jeffrey P.

In: Autophagy, Vol. 10, No. 6, 2014, p. 1120-1136.

Research output: Contribution to journalArticle

Goodall, ML, Wang, T, Martin, KR, Kortus, MG, Kauffman, AL, Trent, JM, Gately, S & MacKeigan, JP 2014, 'Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib', Autophagy, vol. 10, no. 6, pp. 1120-1136. https://doi.org/10.4161/auto.28594
Goodall, Megan L. ; Wang, Tong ; Martin, Katie R. ; Kortus, Matthew G. ; Kauffman, Audra L. ; Trent, Jeffrey M. ; Gately, Stephen ; MacKeigan, Jeffrey P. / Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib. In: Autophagy. 2014 ; Vol. 10, No. 6. pp. 1120-1136.
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