Combination of gemcitabine and anti-PD-1 antibody enhances the anticancer effect of M1 macrophages and the Th1 response in a murine model of pancreatic cancer liver metastasis.

BACKGROUND: Pancreatic ductular adenocarcinoma (PDAC) is among the most dreadful of malignancies, in part due to the lack of efficacious chemotherapy. Immune checkpoint inhibitors, including anti-programmed cell death 1 (anti-PD-1) antibodies, are novel promising forms of systemic immunotherapy. In the current study, we assessed whether gemcitabine (GEM) combined with anti-PD-1 antibody treatment was efficacious as immunochemotherapy for advanced PDAC using a murine model of liver metastasis. METHODS: The murine model of PDAC liver metastasis was established by intrasplenically injecting the murine pancreatic cancer cell line PAN02 into immunocompetent C57BL/6J mice. The mice were treated with an anti-PD-1 antibody, GEM, or a combination of GEM plus anti-PD-1 antibody, and compared with no treatment (control); liver metastases, immune cell infiltration, gene expression, immune cell response phenotypes, and overall survival were investigated. RESULTS: In the metastatic tumor tissues of mice treated with GEM plus anti-PD-1 antibody, we observed the increased infiltration of Th1 lymphocytes and M1 macrophages. Gene expression profile analysis of peripheral blood cells obtained from mice treated with GEM plus anti-PD-1 antibody clearly highlighted T cell and innate immune signaling pathways. Survival of PDAC liver metastasis mice was significantly prolonged by the combination therapy (median survival, 66 days) when compared with that of GEM alone treatment (median survival, 56 days). Expanded lymphocytes, which were isolated from the splenocytes of PDAC liver metastasis mice treated with GEM plus anti-PD-1 antibody, had an increased number of M1 macrophages. CONCLUSION: The combination of anti-PD-1 antibody immunotherapy with GEM was beneficial to treat a murine model of PDAC liver metastasis by enhancing the immune response mediated by Th1 lymphocytes and M1 macrophages and was associated with CD8+ T cells.

Regenerative Therapy for Liver Cirrhosis Based on Intrahepatic Arterial Infusion of Autologous Subcutaneous Adipose Tissue-Derived Regenerative (Stem) Cells: Protocol for a Confirmatory Multicenter Uncontrolled Clinical Trial.

BACKGROUND: Liver cirrhosis results from chronic hepatitis, and is characterized by advanced fibrosis due to long-term hepatic inflammation. Cirrhosis ultimately leads to manifestations of jaundice, ascites, and encephalopathy, and increases the risk of hepatocellular carcinoma. Once cirrhosis is established, resulting in hepatic failure, no effective treatment is available. Therefore, novel therapies to inhibit disease progression of cirrhosis are needed. OBJECTIVE: The objective of this investigator-initiated clinical trial is to assess the safety and efficacy of autologous adipose tissue-derived regenerative (stem) cell therapy delivered to the liver via the hepatic artery in patients with liver cirrhosis. METHODS: Through consultation with the Japan Pharmaceuticals and Medical Devices Agency, we designed a clinical trial to assess a therapy for liver cirrhosis based on autologous adipose tissue-derived regenerative (stem) cells, which are extracted using an adipose tissue dissociation device. The primary endpoints of the trial are the serum albumin concentration, prothrombin activity, harmful events, and device malfunction. RESULTS: Enrollment and registration were initiated in November 2017, and the follow-up period ended in November 2019. Data analysis and the clinical study report will be completed by the end of March 2020. CONCLUSIONS: Completion of this clinical trial, including data analysis, will provide data on the safety and efficacy of this novel liver repair therapy based on autologous adipose tissue-derived regenerative (stem) cells using an adipose tissue dissociation device. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000022601; https://tinyurl.com/w9uqw3q. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/17904.

Distinct chemotherapy-associated anti-cancer immunity by myeloid cells inhibition in murine pancreatic cancer models.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with an extremely poor prognosis. Chemotherapy, such as gemcitabine (GEM), is the only treatment for PDAC patients who are not suitable for radical surgical treatment; however, its anti-tumor efficacy is limited. In this study, we investigated the host immune system response in murine PDAC models undergoing GEM treatment. We found that PDAC tumor tissues were infiltrated with a substantial number of Gr-1+ myeloid cells and had relatively small numbers of CD4+ and CD8+ cells. In addition, there were increased numbers of myeloid cells expressing CD11b+ and Gr-1+ in peripheral blood. When mice with PDAC tumors in the intraperitoneal cavity or liver were treated with GEM, numbers of myeloid cells in tumor tissues and in peripheral blood decreased. In contrast, numbers of CD4+ or CD8+ cells increased. In peripheral blood, the numbers of CD8+ cells expressing interferon-gamma (IFN-γ) were higher in GEM-treated mice than in untreated mice. In addition, GEM treatment in combination with myeloid cell depletion further prolonged the survival of PDAC mice. The gene expression profile of peripheral blood in myeloid cell-depleted PDAC mice treated with GEM showed biological processes related to anti-cancer immunity, such as natural killer cell-mediated cytotoxicity, type I IFN signaling, and co-stimulatory signaling for T cell activation. Thus, in PDAC murine models, GEM treatment was associated with an immune response consistent with an anti-cancer effect, and depletion of myeloid-lineage cells played an important role in enhancing anti-cancer immunity associated with GEM treatment.