journal contribution posted on 2023-03-31, 03:08 authored by Akshay V. Bhat, Monica Palanichamy Kala, Vinay Kumar Rao, Luca Pignata, Huey Jin Lim, Sudha Suriyamurthy, Kenneth T. Chang, Victor K. Lee, Ernesto Guccione, Reshma Taneja
Supplementary Figure S1. Inhibition of G9a activity reduces colony formation. Supplementary Figure S2. Inhibition of G9a expression or activity in RH30 cells impacts proliferation, differentiation and motility Supplementary Figure S3. Inhibition of G9a expression or activity in RH41 cells impacts proliferation, differentiation and motility Supplementary Figure S4. Validation of transcriptome analysis with G9a knockdown cells Supplementary Figure S5. Validation of ChIP-Seq analysis by CHIP-PCR Supplementary Figure S6. Inhibition of RAC1 activity reduces proliferation, migration and invasion Supplementary Table 1. Nanostring PanCancer pathway analysis in siG9a cells
National Medical Research Council
ARTICLE ABSTRACTAlveolar rhabdomyosarcoma (ARMS) is an aggressive pediatric cancer with poor prognosis. As transient and stable modifications to chromatin have emerged as critical mechanisms in oncogenic signaling, efforts to target epigenetic modifiers as a therapeutic strategy have accelerated in recent years. To identify chromatin modifiers that sustain tumor growth, we performed an epigenetic screen and found that inhibition of lysine methyltransferase G9a significantly affected the viability of ARMS cell lines. Targeting expression or activity of G9a reduced cellular proliferation and motility in vitro and tumor growth in vivo. Transcriptome and chromatin immunoprecipitation–sequencing analysis provided mechanistic evidence that the tumor-suppressor PTEN was a direct target gene of G9a. G9a repressed PTEN expression in a methyltransferase activity–dependent manner, resulting in increased AKT and RAC1 activity. Re-expression of constitutively active RAC1 in G9a-deficient tumor cells restored oncogenic phenotypes, demonstrating its critical functions downstream of G9a. Collectively, our study provides evidence for a G9a-dependent epigenetic program that regulates tumor growth and suggests targeting G9a as a therapeutic strategy in ARMS.
These findings demonstrate that RAC1 is an effector of G9a oncogenic functions and highlight the potential of G9a inhibitors in the treatment of ARMS.