Poster Presentation 36th Lorne Cancer Conference 2024

Pro-malignant interactions between clones in head and neck squamous cell carcinomas (#254)

Natnicha Ketchaikosol 1 2 , Greg G. Neely 3 , Naisana Seyedasli 1 4 , Guy J. Lyons 1 2 5
  1. Sydney Medical School, University of Sydney, Camperdown, NSW, Australia
  2. Centenary Institute, University of Sydney, Camperdown, NSW, Australia
  3. School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, Australia
  4. Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
  5. Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia

Head and neck squamous cell carcinomas (HNSCCs) are one of the most common cancers worldwide. Single-cell RNA sequencing has revealed that this cancer often displays genetic intratumoral heterogeneity i.e. the tumours consist of many subpopulations which have their own genetically unique characteristics. This raises the possibility that these clones could interact to enhance tumour initiation, progression, invasion and resistance to therapies. However, clonal interactions between HNSCC subpopulations have not been widely investigated.

The aim of this study is to identify pairs of HNSCC clones that can interact to promote cell proliferation, migration, tumorigenesis and resistance to cytotoxic drugs, and to identify the genes and pathways that mediate those interactions.

CISCCO-02, a HNSCC cell line derived from Confetti mice undergoing 4NQO carcinogenesis, and the human HNSCC cell lines, HN30, SCC9 and SCC25, will be investigated in this study. These cell lines were chosen because there is genetic and/or morphological evidence that they are multiclonal. To study the clonal interactions, each clone will be tagged with a distinctive fluorescent protein. Then they will be cultured individually and as a mixture, and cell proliferation, invasion, migration and drug resistance assays will be performed. When interacting clones have been identified, the pathways which enable those interactions will be identified using a CRISPR knockout lentiviral screen.

To date, all of the mentioned cell lines have been cloned. Two clones, one cyan and one red, were selected from the CISCCO-02 biclonal Confetti mouse HNSCC cell line. Intravital imaging of the tumour that gave rise to the cell line showed that the cyan clone grew slowly until it was invaded by the adjacent red clone, at which point tumour growth began and rapidly grew. HN30, SCC9 and SCC25 clones stably maintain their epithelial and mesenchymal morphologies. These preliminary data showed that these HNSCC cell lines have dimorphic clones, and they could potentially interact to promote tumour progression. Nevertheless, the interactions between these clones remain to be investigated.