Poster Presentation 37th Lorne Cancer Conference 2025

Modulating mRNA translation to prevent cancer cell state switching (#116)

Christina HT Bui 1 2 3 , Vanina Rodriguez 2 3 , Cerys McCool 1 2 3 , Shabarni Gupta 1 2 3 , Heloisa Helena Milioli 1 2 3 , Christine L Chaffer 1 2 3
  1. St Vincent's Clinical School, UNSW Medicine, UNSW Sydney, Darlinghurst, NSW, Australia
  2. The Kinghorn Cancer Centre, Darlinghurst, NSW, Australia
  3. The Garvan Institute of Medical Research, Darlinghurst, NSW, Australia

Cancer cell plasticity, a hallmark of cancer, underpins intratumoral heterogeneity by enabling cancer cells to traverse a phenotypic cell state landscape 1,2. The non-genetic mechanisms that drive cell state plasticity, including epigenetics and mRNA translation, facilitate rapid and dynamic adaption to their evolving microenvironment and therapeutic insults3,4. This fosters the emergence of the aggressive cancer stem cell (CSC) state. Although adjuvant therapy aims to lower the chances of disease recurrence, CSCs can evade treatment and remain dormant in different tissues in the body for years and even decades5,6. Recently, we have discovered unique components of the mRNA translation machinery that are critical to the CSC state. Targeting this machinery may be crucial in preventing resistance and relapse, offering a novel curative approach and ultimately improve patient outcomes7,8.

Through RNA-seq, we have identified Eukaryotic Initiation Factor 5-A (EIF5A) as a translational vulnerability that may play an important role in the CSC state. Importantly, EIF5A is one of two highly conserved, known proteins that can undergo hypusination, a post-translational modification that activates EIF5A function 9–11. Once activated, EIF5A plays a global role in protein synthesis and is implicated in various processes including cell proliferation, survival and tumorigenesis. Now, we will determine whether EIF5A and/or the hypusination of EIF5A (EIF5Ahyp) are essential to the CSC state by generating a CRISPR-Cas9 model of EIF5A and performing site-directed mutagenesis to generate an EIF5Ahyp knockdown model. We will then define the EIF5A- and EIF5Ahyp-dependent translatome in CSCs by performing RNA-sequencing in combination with matched ribosomal profiling of the generated models. Preliminary results revealed that low concentrations of EIF5Ahyp inhibitor significantly decreased CSC proliferation and enhanced chemotherapeutic efficacy in vitro. We further identified inhibition of CSC tumorigenicity and migration capabilities, by tumorsphere formation and wound healing assay. In vivo, combination therapy impaired tumour growth and significantly improved survival of xenograft breast cancer models. This pioneering study highlights a promising future direction for CSC research with potential to break new grounds for clinical translation, exploiting mRNA translation therapeutic vulnerabilities to eradicate resistant disease and preventing recurrence, ultimately improving patient survival and quality of life.

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