The novel reversible LSD1 inhibitor SP-2577 promotes anti-tumor immunity in SWItch/Sucrose-NonFermentable (SWI/SNF) complex mutated ovarian cancer

PLoS One. 2020 Jul 10;15(7):e0235705. doi: 10.1371/journal.pone.0235705. eCollection 2020.

Abstract

Mutations of the SWI/SNF chromatin remodeling complex occur in 20% of all human cancers, including ovarian cancer. Approximately half of ovarian clear cell carcinomas (OCCC) carry mutations in the SWI/SNF subunit ARID1A, while small cell carcinoma of the ovary hypercalcemic type (SCCOHT) presents with inactivating mutations of the SWI/SNF ATPase SMARCA4 alongside epigenetic silencing of the ATPase SMARCA2. Loss of these ATPases disrupts SWI/SNF chromatin remodeling activity and may also interfere with the function of other histone-modifying enzymes that associate with or are dependent on SWI/SNF activity. One such enzyme is lysine-specific histone demethylase 1 (LSD1/KDM1A), which regulates the chromatin landscape and gene expression by demethylating proteins such as histone H3. Cross-cancer analysis of the TCGA database shows that LSD1 is highly expressed in SWI/SNF-mutated tumors. SCCOHT and OCCC cell lines have shown sensitivity to the reversible LSD1 inhibitor SP-2577 (Seclidemstat), suggesting that SWI/SNF-deficient ovarian cancers are dependent on LSD1 activity. Moreover, it has been shown that inhibition of LSD1 stimulates interferon (IFN)-dependent anti-tumor immunity through induction of endogenous retroviral elements and may thereby overcome resistance to checkpoint blockade. In this study, we investigated the ability of SP-2577 to promote anti-tumor immunity and T-cell infiltration in SCCOHT and OCCC cell lines. We found that SP-2577 stimulated IFN-dependent anti-tumor immunity in SCCOHT and promoted the expression of PD-L1 in both SCCOHT and OCCC. Together, these findings suggest that the combination therapy of SP-2577 with checkpoint inhibitors may induce or augment immunogenic responses of SWI/SNF-mutated ovarian cancers and warrants further investigation.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • B7-H1 Antigen / genetics
  • B7-H1 Antigen / metabolism
  • Carcinoma, Small Cell / genetics
  • Carcinoma, Small Cell / pathology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chromosomal Proteins, Non-Histone / genetics*
  • Culture Media, Conditioned / chemistry
  • Culture Media, Conditioned / pharmacology
  • DNA Helicases / genetics
  • DNA Helicases / metabolism
  • DNA-Binding Proteins / antagonists & inhibitors*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Female
  • Gene Expression Regulation / drug effects
  • Histones / genetics
  • Histones / metabolism
  • Humans
  • Interferons / pharmacology
  • Mutation
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Ovarian Neoplasms / genetics
  • Ovarian Neoplasms / immunology
  • Ovarian Neoplasms / pathology
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects*
  • T-Lymphocytes / immunology
  • Transcription Factors / antagonists & inhibitors*
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism

Substances

  • ARID1A protein, human
  • Antineoplastic Agents
  • B7-H1 Antigen
  • CD274 protein, human
  • Chromosomal Proteins, Non-Histone
  • Culture Media, Conditioned
  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • Histones
  • Nuclear Proteins
  • SWI-SNF-B chromatin-remodeling complex
  • Transcription Factors
  • Interferons
  • SMARCA4 protein, human
  • DNA Helicases