Background & Aims
Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting side effect of chemotherapy resulting from pathological changes to peripheral nerves, neuronal accessory cells and immune cells [1,2,3,4]. We have previously demonstrated that vincristine activates the Nod-Like-Receptor 3 (NLRP3) inflammasome, leading to the release of nerve-sensitising interleukin-1β (IL-1β) from macrophages in the proximity of peripheral nerves [1]. Additionally, treatment with anakinra, a drug targeting IL-1β signalling, prevents vincristine-induced neuropathy without affecting anti-cancer efficacy [1]. However, chemotherapy is always administered as a combination regimen, with unknown effects on CIPN development [2]. The CVAD (cyclophosphamide, vincristine, doxorubicin and dexamethasone) regimen is commonly used to treat leukaemia and lymphomas. The aim of this project was to develop a clinically relevant mouse model of CVAD-induced CIPN to identify mechanisms and novel targets.
Methods
Mice were injected intraperitoneally with cyclophosphamide (50 mg/kg), vincristine (0.25 mg/kg), doxorubicin (20 mg/kg) and dexamethasone (10 mg/kg), and co-treated with anakinra (100 mg/kg). Changes to the mechanical paw withdrawal thresholds were assessed using the electronic von Frey apparatus (MouseMet, TopCat Metrology). Deficits in neuromuscular function were measured using the grip strength meter (Stoelting) and complete blood count analysis was performed using the BC5000 Haematology Analyser (Mindray Bio-Medical Electronics Co.). Immunohistochemical staining of dorsal root ganglia (DRGs) and sciatic nerves with the F4/80 antibody (Clone CI:A3-1, Novus Biologicals) was carried out to determine if neuroinflammation contributes to the development of CVAD-induced neuropathy.
Results
Our CVAD model reproduced sensory and motor neuropathy. CVAD-treated mice developed mechanical allodynia, albeit with differences in severity during the early stage of CVAD- and single drug-induced neuropathy, suggesting that sensory symptoms develop in a drug- and time-dependent manner with synergistic effects. Anakinra, as a pre-treatment, ultimately reduced sensory symptoms by 40% after eight days of treatment and completely protected mice from motor neuropathy. Haematological assessment revealed a decline in blood monocyte counts on day 2 and an increase on day 9. Furthermore, histological assessment of peripheral nerves revealed a decrease in the percentage of F4/80+-stained area on day 2, indicating a reduction in inflammatory cell infiltration. However, the number of F4/80+ macrophages increased again on day 9, indicating the infiltration of inflammatory cells.
Conclusions
We have developed a clinically relevant mouse model of the CVAD combination regimen to understand the pathophysiology of CIPN and screened for potential therapeutic targets to ultimately bridge the gap between basic science and clinical practice. Collectively, our data suggest that F4/80+ cells contribute to the development of neuropathy, with IL-1β playing a more dominant role in the later stages. At present, we have demonstrated that anakinra only partially alleviates CVAD-induced neuropathy. However, the data obtained from various mouse models developed during this project will provide new insights into the mechanisms of CVAD-induced peripheral neuropathy, allow the identification of novel targets for the treatment of neuropathic pain and pave the way for a more applicable bench-to-bedside translation towards the development of effective CIPN strategies.
References
1. Starobova H, Monteleone M, Adolphe C, Batoon L, Sandrock CJ, Tay B, et al. Vincristine-induced peripheral neuropathy is driven by canonical NLRP3 activation and IL-1beta release. J Exp Med 2021;218(5). 2. Tay N, Laakso EL, Schweitzer D, Endersby R, Vetter I, Starobova H. Chemotherapy-induced peripheral neuropathy in children and adolescent cancer patients. Front Mol Biosci 2022;9:1015746. 3. Starobova H, Alshammari A, Winkler IG, Vetter I. The role of the neuronal microenvironment in sensory function and pain pathophysiology. J Neurochem 2022. 4. Gilchrist L. Chemotherapy-induced peripheral neuropathy in pediatric cancer patients. Semin Pediatr Neurol 2012;19(1):9-17.
Poster Authors
Nicolette Tay
School of Pharmacy, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author
Svetlana Shatunova
Master of Biotechnology
Institute for Molecular Bioscience, The University of Queensland, Saint Lucia, QLD, Australia
Lead Author
Ammar Alshammari
MSc & BSc
Institute for Molecular Bioscience, The University of Queensland, Saint Lucia, QLD, Australia
Lead Author
Simranpreet Kaur
Mater Research Institute, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author
Allison Petitt
Mater Research Institute, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author
Ingrid Winkler
PhD
Mater Research Institute, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author
Hana Starobova
PhD & MPharm
Mater Research Institute, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author
Irina Vetter
PhD & BPharm (Hons)
School of Pharmacy, The University of Queensland, Woolloongabba, QLD, Australia
Lead Author