Oral Presentation NSW State Cancer Conference 2023

Targeting Urokinase Plasminogen Activator Combined with Gemcitabine Enhances Immune Regulation and Inhibits Metastasis in Pancreatic Cancer (#57)

S M Zahid HOSEN 1 2 , Zhihong Xu 1 2 , Alpha Mekapogu 1 2 , Chamini Perera 1 2 , Romano Pirola 1 , David Goldstein 1 , Jeremy Wilson 1 , Benjamin Buckley 3 4 , Marie Ranson 3 4 , Minoti Apte 1 2
  1. Pancreatic Research Group, South Western Sydney Clinical School, Faculty of Medicine, , Sydney, NSW, Australia
  2. Ingham Institute for Applied Medical Research, Liverpool, Sydney, NSW, Australia
  3. Molecular Horizons and School of Chemistry & Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
  4. Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia

Background and Aim: The serine protease, urokinase plasminogen activator (uPA), is implicated in the stromal-tumour interactions that mediate pancreatic cancer progression. Although uPA inhibition has previously shown promise in immunocompromised mouse models of PC, these models lack the important immune system that is known to play a key role in cancer biology. Therefore, the present study aims to evaluate the effects of uPA inhibition alone and in combination with the chemotherapeutic agent on pancreatic cancer growth and metastasis in an immunocompetent setting.

Methods: A syngeneic orthotopic model of PC was used where genetically engineered mouse pancreatic cancer cells (KRasG12D , P53R172H, Cre-Pdx1; KPC cells)  + mouse pancreatic stellate cells (PSCs, which produce the collagenous stroma of PC) were injected into the pancreas of C57BL6 mice. Two weeks post-implantation, tumour development was assessed by ultrasound before randomising mice to four treatment groups (n=7/group): vehicle control (C), Gemcitabine (G; 75 mg/kg IP biweekly), uPA inhibitor BB230F (U; 10 mg/kg IP daily), and a combination of Gemcitabine and uPA inhibitor (G+U). After a five-week treatment period, tumour volume and metastasis were assessed, followed by immunohistochemistry and morphometric analysis of tumour sections for cancer cell proliferation, epithelial-mesenchymal transition (EMT) and stemness, extracellular matrix (ECM) deposition, and immune cell infiltration (total T cells (CD3+), helper T cells (CD4+), cytotoxic T cells (CD8+), macrophages and bone marrow-derived suppressor cells (MDSCs)).

Results: uPA inhibition or Gemcitabine alone, and in combination, significantly reduced tumour volume compared to the vehicle control. uPA inhibition alone, but not Gemcitabine, decreased metastasis. Strikingly, the combination of uPA inhibition and Gemcitabine completely eliminated visible metastasis in the liver. Cancer cell proliferation, EMT and stemness were significantly decreased by uPA inhibition alone and in combination with Gemcitabine. Most importantly, uPA inhibition alone and in combination with Gemcitabine significantly increased the infiltration of cytotoxic T cells into the tumour while decreasing helper T cell and M2 macrophage numbers. MDSC numbers remained unchanged. These effects were associated with a significant reduction in intratumoral expression of TGFb (a cytokine known to facilitate an immunosuppressive environment in tumours).

Conclusion: The combined approach of targeting stromal-tumour interactions with uPA inhibitors and cancer cells with chemotherapy effectively reduced tumour volume, facilitated anti-tumour immunity and eliminated metastasis in an immunocompetent PC model. Our results support the potential of uPA inhibition alone or in combination with chemotherapy as a promising therapeutic strategy for pancreatic cancer.