Flash Talk + Poster Presentation 37th Lorne Cancer Conference 2025

Enhancing Tumour Response in Pancreatic Cancer: The Role of Itraconazole (#120)

Diego Chacon-Fajardo 1 2 , Sean Porazinski 1 2 , Jennifer Man 1 2 , Howard Yim 3 , Emad El-Omar 3 , Anthony Joshua 1 2 , Marina Pajic 1 2
  1. Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
  2. St Vincent’s Clinical School, Clinical School, Faculty of Medicine, Sydney, NSW, Australia
  3. Microbiome Research Centre, St George and Sutherland Clinical School, UNSW , Sydney, NSW, Australia

Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival of only 10% and persists as the third most common cause of cancer-related death in Western societies. As precision medicine revolutionises healthcare and treatment of diseases, patients with pancreatic cancer (PC) are gaining new hope with the development of molecular-guided therapies that modulate signalling within tumours and their ecosystem[1-4]. In this study, single-cell transcriptomics (scRNAseq) and bioinformatics were used to validate and further understand how Itraconazole (ITZ), a clinically-used anti-fungal agent, enhances the overall tumour response of an in vivo genetically-engineered KPC model (LSL-KrasG12D;LSL-Trp53R172H/+) of PC.

scRNAseq analysis allowed to elucidate the effects of ITZ on PC tumours, beyond basal and classical classification. By studying epithelial-mesenchymal transition (EMT) across subsets, it was found a uniform decrease of the mesenchymal phenotype, associated with enhanced migration and modulation of the immune microenvironment [5,6]. Interestingly, using a signature associated with KRT17high/CXCL8+ cells, a Basal/Classical intermediary population was identified in the model, reducing its abundance by half upon ITZ treatment. Our findings resembled the effects of chemotherapy in responsive patients and reinforces the importance of chemokine CXCL8, a human neutrophil-attracting chemokine, and a prognostic marker which can modulate the infiltration of Tumour Associated Neutrophils (TANs)[7,8].

To further investigate how ITZ affects the immune system, we evaluated gene expression and cellular crosstalk in myeloid and lymphoid subsets. Our findings suggest that ITZ treatment led to positive changes within macrophages, including enrichment of M1-like pro-inflammatory phenotype, confirmed via immunofluorescence. The response was further associated with positive signalling via Cxcl9-Cxcr3 and Tnf1rs-1a/1b. On the other hand, after identifying diversity of TANs, downregulation of the chemokine Cxcr2 was present across subtypes following treatment, thus dampening tumour-TANs interaction via Cxcl1/2/5-Cxcr2. Remarkably, Cxcl1/2/5 chemokines are the murine homolog of human CXCL8, making ITZ a potential inhibitor of TANs infiltration, thus reducing metastasis and enhancing survival[7,9]. Lastly, in Cd8+ T cells, upregulation of TNF-α signalling via NF-κB signalling along the effector lineage was linked to regulation of immune functions and inflammatory response[10].

In conclusion, our integrated bioinformatic and molecular studies provide scientific rationale for the development of ITZ and immunotherapy combination in PC.

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