Oncotarget

Research Papers:

This article has been corrected. Correction in: Oncotarget. 2019; 10:5120-5122.

HDAC inhibitors enhance neratinib activity and when combined enhance the actions of an anti-PD-1 immunomodulatory antibody in vivo

Laurence Booth, Jane L. Roberts, Andrew Poklepovic, Francesca Avogadri-Connors, Richard E. Cutler, Alshad S. Lalani and Paul Dent _

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Oncotarget. 2017; 8:90262-90277. https://doi.org/10.18632/oncotarget.21660

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Abstract

Laurence Booth1, Jane L. Roberts1, Andrew Poklepovic2, Francesca Avogadri-Connors3, Richard E. Cutler3, Alshad S. Lalani3 and Paul Dent1

1Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA

2Department of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA

3Puma Biotechnology Inc., Los Angeles, CA 90024, USA

Correspondence to:

Paul Dent, email: paul.dent@vcuhealth.org

Keywords: autophagy, HDAC, receptor tyrosine kinase, neratinib

Received: August 21, 2017    Accepted: September 13, 2017    Published: October 09, 2017

ABSTRACT

Patients whose NSCLC tumors become afatinib resistant presently have few effective therapeutic options to extend their survival. Afatinib resistant NSCLC cells were sensitive to clinically relevant concentrations of the irreversible pan-HER inhibitor neratinib, but not by the first generation ERBB1/2/4 inhibitor lapatinib. In multiple afatinib resistant NSCLC clones, HDAC inhibitors reduced the expression of ERBB1/3/4, but activated c-SRC, which resulted in higher total levels of ERBB1/3 phosphorylation. Neratinib also rapidly reduced the expression of ERBB1/2/3/4, c-MET and of mutant K-/N-RAS; K-RAS co-localized with phosphorylated ATG13 and with cathepsin B in vesicles. Combined exposure of cells to [neratinib + HDAC inhibitors] caused inactivation of mTORC1 and mTORC2, enhanced autophagosome and subsequently autolysosome formation, and caused an additive to greater than additive induction of cell death. Knock down of Beclin1 or ATG5 prevented HDAC inhibitors or neratinib from reducing ERBB1/3/4 and K-/N-RAS expression and reduced [neratinib + HDAC inhibitor] lethality. Neratinib and HDAC inhibitors reduced the expression of multiple HDAC proteins via autophagy that was causal in the reduced expression of PD-L1, PD-L2 and ornithine decarboxylase, and increased expression of Class I MHCA. In vivo, neratinib and HDAC inhibitors interacted to suppress the growth of 4T1 mammary tumors, an effect that was enhanced by an anti-PD-1 antibody. Our data support the premises that neratinib lethality can be enhanced by HDAC inhibitors, that neratinib may be a useful therapeutic tool in afatinib resistant NSCLC, and that [neratinib + HDAC inhibitor] exposure facilitates anti-tumor immune responses.


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