Poster Presentation Hunter Cell Biology Meeting 2025

CSPG4 as a driver of malignancy in aggressive squamous cell carcinoma (#215)

Jasmine M Zhou 1 , Kathryn Chen 2 , Chen Wang 1 , Fiaz R Chowdhury 1 , Verena Wally 3 , Roland Zauner 3 , Josefina Pinon-Hofbauer 3 , Guy Lyons 4 , Kieran F Scott 2 , Paul de Souza 1 5 , Albert S Mellick 1 5
  1. Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
  2. Medicine, Western Sydney University, Sydney, NSW, Australia
  3. Department of Dermatology and Allergology, EB House Austria, Salzburg, Austria
  4. Centenary Institute, University of Sydney, Camperdown, NSW, Australia
  5. Nepean Clinical School, University of Sydney, Nepean, New South Wales, Australia

Introduction: Chondroitin sulfate proteoglycan 4 (CSPG4) is a cell surface proteoglycan that plays a role in angiogenesis and malignancy in melanoma, but whose role in nonmelanoma skin cancer is less well defined. While early evidence showed some link between CSPG4 expression and malignancy in squamous cell carcinomas (SCCs), the advent of new monoclonal antibodies (mAb) has allowed us to re-examine the role of CSPG4 in SCCs. Examination of the TCGA gene expression data showed that CSPG4 mRNA expression is associated with reduced patient outcome in SCCs, and CSPG4 expression correlated with the partial epithelial to mesenchymal transition (EMT) and tumour-specific keratinocyte fingerprint recently identified through single-cell sequencing. Understanding how CSPG4 may play a role in malignancy is particularly important given that deaths from SCCs are increasing worldwide and there is a need to identify new markers and targets for therapy. Many SCCs are inoperable, such as those that develop post-chemotherapy; and in many cases such as in epidermolysis bullosa (EB), a rare genetic condition resulting in fragile skin, death can occur rapidly following diagnosis, leading to the need for more effective surveillance tools.

 

Methods: To assess the link between CSPG4 and malignancy, we examined CSPG4 protein levels in primary cell lines derived from patients with aggressive SCCs using next-generation anti-CSPG4 mAbs. In addition, we have developed a model for the in-vitro examination of circulating tumour cells (CTCs) by studying the nonadherent cell fraction of cultured cells and comparing results from CTCs obtained from patient blood using ScreenCell® filtration.

 

Results: We have shown that CSPG4 is upregulated in malignant SCCs, including those from patients with EB. We have examined the nonadherent cell fraction and shown enhanced expression of CSPG4 in cells that have undergone EMT, and we have identified differential expression for CSPG4 in CTCs isolated from the blood of patients. In the process, we have developed a bespoke AI-machined learning workflow to automate CTC detection on filter membranes using morphology and fluorescent marker detection.

 

Conclusion: Our work is ongoing, but our current findings suggest that CSPG4 is upregulated in malignant SCCs that have undergone EMT and might be used to mark clinically important cells circulating in the blood of cancer patients. These results suggest that CSPG4 may be a driver of malignancy in SCC. In the future, we will use this information to begin developing a minimally invasive blood-based surveillance protocol using CSPG4 as a marker.

  1. Wilson, B.S., Imai, K., Natali, P.G. & Ferrone, S. Distribution and molecular characterization of a cell-surface and a cytoplasmic antigen detectable in human melanoma cells with monoclonal antibodies. Int J Cancer 28, 293-300 (1981).
  2. Price, M.A., et al. CSPG4, a potential therapeutic target, facilitates malignant progression of melanoma. Pigment Cell Melanoma Res 24, 1148-1157 (2011).
  3. Kivisaari, A. & Kähäri, V.M. Squamous cell carcinoma of the skin: Emerging need for novel biomarkers. World J Clin Oncol 4, 85-90 (2013).
  4. Liu J, Lian J, Chen Y, Zhao X, Du C, Xu Y, Hu H, Rao H, Hong X. Circulating Tumor Cells (CTCs): A Unique Model of Cancer Metastases and Non-invasive Biomarkers of Therapeutic Response. Front Genet. 2021 Aug 25;12:734595. doi: 10.3389/fgene.2021.734595
  5. Vidlarova M, Rehulkova A, Stejskal P, Prokopova A, Slavik H, Hajduch M, Srovnal J. Recent Advances in Methods for Circulating Tumor Cell Detection. Int J Mol Sci. 2023 Feb 15;24(4):3902. doi: 10.3390/ijms24043902
  6. Illmer, J., et al. miR-200b-mediated reversion of a spectrum of epithelial to mesenchymal transition states in recessive dystrophic epidermolysis bullosa squamous cell carcinomas. Br J Dermatol (2023).