Truncated HDAC9 identified by integrated genome-wide screen as the key modulator for paclitaxel resistance in triple-negative breast cancer

Theranostics. 2020 Sep 2;10(24):11092-11109. doi: 10.7150/thno.44997. eCollection 2020.

Abstract

Rationale: Paclitaxel resistance is a major concern when treating triple-negative breast cancer (TNBC) patients. We aimed to identify candidates causing paclitaxel resistance and explore their significance in TNBC therapeutics. Methods: A genome-wide CRISPR screening, integrated with transcriptome analyses, was performed to identify candidates involved in paclitaxel-resistant TNBCs. Cell proliferation, cytotoxicity, immunofluorescent staining, and xenograft assays were conducted to verify the phenotypes of paclitaxel resistance induced by candidate genes, both in vitro and in vivo. RNA sequencing, Western blotting, and chromatin immunoprecipitation assays were used to explore the underlying mechanisms. Results: MEF2-interacting transcriptional repressor (MITR), the truncated isoform of histone deacetylase 9 (HDAC9) lacking the deacetylation domain, was enriched in paclitaxel-resistant cells. Elevated MITR expression resulted in increased interleukin-11 (IL11) expression and activation of downstream JAK/STAT3 signaling. Mechanistically, MITR counteracted MEF2A-induced transcriptional suppression of IL11, ultimately causing paclitaxel resistance. By contrast, pharmacological inhibition of JAK1/2 by ruxolitinib reversed paclitaxel resistance both in vitro and in vivo. Conclusion: Our in vitro and in vivo genetic and cellular analyses elucidated the pivotal role of MITR/MEF2A/IL11 axis in paclitaxel resistance and provided a novel therapeutic strategy for TNBC patients to overcome poor chemotherapy responses.

Keywords: CRISPR screen; HDAC9; MITR; breast cancer; paclitaxel resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / genetics
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Datasets as Topic
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression Regulation, Neoplastic / genetics
  • Gene Knockdown Techniques
  • Gene Knockout Techniques
  • HEK293 Cells
  • Histone Deacetylases / genetics
  • Histone Deacetylases / metabolism*
  • Humans
  • Interleukin-11 / genetics
  • Janus Kinases / antagonists & inhibitors
  • Janus Kinases / metabolism
  • Kaplan-Meier Estimate
  • MEF2 Transcription Factors / genetics
  • MEF2 Transcription Factors / metabolism
  • Mice
  • Nitriles
  • Paclitaxel / pharmacology*
  • Paclitaxel / therapeutic use
  • Pyrazoles / pharmacology
  • Pyrazoles / therapeutic use
  • Pyrimidines
  • RNA-Seq
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Triple Negative Breast Neoplasms / drug therapy*
  • Triple Negative Breast Neoplasms / genetics
  • Triple Negative Breast Neoplasms / mortality
  • Triple Negative Breast Neoplasms / pathology
  • Xenograft Model Antitumor Assays

Substances

  • IL11 protein, human
  • Interleukin-11
  • MEF2 Transcription Factors
  • MEF2A protein, human
  • Nitriles
  • Pyrazoles
  • Pyrimidines
  • Repressor Proteins
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • ruxolitinib
  • Janus Kinases
  • HDAC9 protein, human
  • Histone Deacetylases
  • Paclitaxel