Chemotherapy-induced infiltration of neutrophils promotes pancreatic cancer metastasis via Gas6/AXL signalling axis

ObjectivePancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease and cytotoxic chemotherapy is the standard of care treatment for patients with advanced disease. Here, we investigate how the microenvironment in PDAC liver metastases reacts to chemotherapy and its role in metastatic disease progression post-treatment, an area which is poorly understood.DesignThe impact of chemotherapy on metastatic disease progression and immune cell infiltrates was characterised using flow and mass cytometry combined with transcriptional and histopathological analysis in experimental PDAC liver metastases mouse models. Findings were validated in patient derived liver metastases and in an autochthonous PDAC mouse model. Human and murine primary cell cocultures and ex vivo patient-derived liver explants were deployed to gain mechanistical insights on whether and how chemotherapy affects the metastatic tumour microenvironment.ResultsWe show that in vivo, chemotherapy induces an initial infiltration of proinflammatory macrophages into the liver and activates cytotoxic T cells, leading only to a temporary restraining of metastatic disease progression. However, after stopping treatment, neutrophils are recruited to the metastatic liver via CXCL1 and 2 secretion by metastatic tumour cells. These neutrophils express growth arrest specific 6 (Gas6) which leads to AXL receptor activation on tumour cells enabling their regrowth. Disruption of neutrophil infiltration or inhibition of the Gas6/AXL signalling axis in combination with chemotherapy inhibits metastatic growth. Chemotherapy increases Gas6 expression in circulating neutrophils from patients with metastatic pancreatic cancer and recombinant Gas6 is sufficient to promote tumour cell proliferation ex vivo, in patient-derived metastatic liver explants.ConclusionCombining chemotherapy with Gas6/AXL or neutrophil targeted therapy could provide a therapeutic benefit for patients with metastatic pancreatic cancer.

Anlotinib Plus Toripalimab and Nab-Paclitaxel in Patients with Locally Advanced or Metastatic Pancreatic Cancer: Study Protocol for An Open-Label, Non-Randomized, Phase II Study (ATNPA)

Background There have not been standard second-line or maintenance regimens with definite survival benefits so far for patients with pancreatic carcinoma who have lost the opportunity of curable resections or failed first-line chemotherapy. Anlotinib, a potent small-molecule tyrosine kinase inhibitor, exhibits anti-angiogenic and anti-tumour effects by specifically binding to multiple targets such as VEGFR, FGFR, PDGFR, c-Kit and Ret. Toripalimab, a novel anti-PD-1 mAb, has been proved to significantly prolong progression-free survival (PFS) and overall survival (OS) in various solid tumours with manageable toxicities when combining with cytotoxic chemotherapy. We design this study to assess the combination of anlotinib, toripalimab and nab-paclitaxel as a second-line or maintenance therapy for locally advanced pancreatic cancer (LAPC) or metastatic pancreatic cancer (MPC). Patients and Methods: This is an open-label, non-randomized, single-arm phase Ⅱ study, aimed at evaluating the efficacy and safety profile of the above-mentioned combination strategy in first-line therapy-failed LAPC or MPC. Totally 53 patients are to be enrolled and receive anlotinib (12 mg, po. qd.) plus toripalimab (240 mg, ivgtt. q3w.) and nab-paclitaxel (125 mg/m2, ivgtt, d1, d8) every 3 weeks as a cycle until disease progression or intolerable adverse events. The primary endpoint is PFS. Secondary end points include OS, disease control rate (DCR), object response rate (ORR), quality of life (QoL) and safety. Enrollment started in April 2021, and follow-up will be finished in April 2023. Discussion and Significance: Combination of anlotinib, toripalimab and nab-paclitaxel may promote vessel normalization and drug delivery, and activate the immune response, thus exerting synergistic anti-tumour effects and counteracting the immunosuppressive microenvironment of pancreatic cancer. As the first intending to assess this combination in pancreatic cancer, this study will provide comprehensive evidence for second-line or maintenance therapy of LAPC and MPC. Trial registration: ClinicalTrials.gov: ATNPA, NCT04718701. Registered January 22, 2021. (https://clinicaltrials.gov/ct2/show/NCT04718701?term=NCT04718701&draw=2&rank=1)