Induction of cytotoxic effector cells towards cholangiocellular, pancreatic, and colorectal tumor cells by activation of the immune checkpoint CD40/CD40L on dendritic cells.

INTRODUCTION: Gastrointestinal (GI) malignancies, such as cholangiocarcinoma, pancreatic carcinoma, and metastatic colorectal carcinoma, have a poor prognosis and effective therapeutic approaches are still challenging. Checkpoint inhibition with PD-1 or PDL-1 antibodies revealed promising results in different tumor entities; however, only few patients with GI tumors can potentially benefit from PD1/PDL1 inhibiting immunotherapy. Further immunotherapeutic strategies for GI malignancies are urgently needed. The aim of this study was to demonstrate that in vitro activation of the immune checkpoint CD40/CD40L can improve DC action towards bile duct, pancreas, and colorectal carcinoma. METHODS: Human DC were isolated from buffy coats from healthy donors, pulsed with tumor lysates and then transduced with adenoviruses encoding human CD40L (Ad-hCD40L). Using transwell assays, the effects of (m)CD40L on DC immunoactivation compared to (s)CD40L were analyzed. Surface marker and cytokine/chemokine expression were measured by flow cytometry, ELISA and cytokine arrays. Capacity of Ad-hCD40L-transduced DC to induce tumor-specific effector cells was tested using MTT proliferation assay and cytotoxicity assays. Apoptosis induction on tumor cells after culturing with supernatants of Ad-hCD40L-transduced DC was analyzed by flow cytometry. RESULTS: Ad-hCD40L transduction induced a high expression of (s)CD40L and (m)CD40L on DC and seemed to induce a strong cellular CD40/CD40L interaction among DC, leading to the formation of cell aggregates. Due to the CD40/CD40L interaction, a significant upregulation of DC maturation markers and a Th1-shift on cytokines/chemokines in the supernatant of DC were achieved. Interestingly, a pure Th1-shift was only achieved, when a cellular CD40/CD40L interaction among DC took place. (s)CD40L induced almost no upregulation of maturation markers and rather resulted in a Th2-cytokine expression, such as IL-10. Correspondingly, (m)CD40L-expressing DC led to significant proliferation and stimulation of tumor-specific effector cells with increased cytotoxicity towards pancreatic, bile duct and colorectal tumor cells. Supernatants of Ad-hCD40L-transduced DC could also induce apoptosis in the different tumor cells in vitro. CONCLUSION: Stimulation of the immune checkpoint CD40L/CD40 by endogenous expression of (m)CD40L provokes a cellular interaction, which increases the immunomodulatory capacity of DC. A Th1 cytokine/chemokine expression is induced, leading to a significant proliferation and enabling cytotoxicity of effector cells towards human bile duct, pancreatic and colorectal tumor cells. The present data point to the promising approach for DC-based immunotherapy of gastrointestinal malignances by activating the CD40/CD40L immune checkpoint.

Programmed cell death protein 1 (PD-1)-inhibition in hepatocellular carcinoma (HCC): a single center experience.

BACKGROUND: The prognosis for advanced Hepatocellular carcinoma (HCC)is still very poor. Despite initial usefulness of immune checkpoint inhibitor (PD-1), phase 3 trials failed to show significant benefit of PD-1 inhibition with nivolumab or pembrolizumab in the first and second line therapy of HCC. Clinical evidence of PD-1 inhibition in patients with advanced and heavily pretreated HCC outside clinical trials is extremely limited. In this study, we analyzed the clinical experience with PD-1 inhibition in patients with heavily pretreated HCC. METHODS: Between May 2016 and January 2019 14 patients with advanced and heavily pretreated HCC were treated with nivolumab or pembrolizumab at the University Hospital Bonn, Germany. Base line characteristics prior to immunotherapy, immunohistochemistry of different immunological markers, beneficial outcome and safety were recorded and retrospectively analyzed. RESULTS: Immunotherapy with PD-1 inhibition was well tolerated and resulted in significant clinical benefit as last line therapy. Median overall survival (OS) was 6.6 months (95%CI:3.9-11.8), progression-free survival (PFS) was 5.3 months (95%CI:2.4-11.7) and overall response rate (ORR) was 30.8%. One patient reached a complete remission. CONCLUSIONS: Despite numerous pretreatments, PD-1 inhibition was well tolerated and showed clinical benefit in patients with heavily pretreated HCC.

Combined photodynamic therapy with systemic chemotherapy for unresectable cholangiocarcinoma.

BACKGROUND: Chemotherapy with gemcitabine and cisplatin is the current standard for patients with unresectable cholangiocarcinoma. Local photodynamic therapy has also demonstrated benefit in patients with extrahepatic cholangiocarcinoma. AIM: To evaluate the benefit of photodynamic therapy in combination with systemic chemotherapy in advanced extrahepatic cholangiocarcinoma. METHODS: Three hundred and fifty-three patients diagnosed with cholangiocarcinoma between 2004 and 2016 were treated at the University Hospital of Bonn, Germany. Of these, 96 suffering from unresectable extrahepatic cholangiocarcinoma were included. Patients were stratified according to treatment: combination photodynamic therapy and chemotherapy (36 patients), photodynamic therapy alone (34 patients), and chemotherapy alone (26 patients). RESULTS: Combined photodynamic therapy with chemotherapy resulted in significantly longer overall survival than chemotherapy alone (P = 0.022). Median survival was 20 months in the combination group (95% CI: 16.38-23.62), 15 months in the photodynamic alone group (95% CI: 10.02-19.98) and 10 months in the chemotherapy alone group (95% CI: 8.45-11.55). In multivariate analysis, combination therapy and photodynamic therapy alone (HR: 0.41, 95% CI: 0.22-0.77, P = 0.006), metal stenting, and radiofrequency ablation were independent predictors of longer survival. CONCLUSIONS: Combination photodynamic therapy and chemotherapy was well tolerated and resulted in significantly longer survival than chemotherapy alone. Application of photodynamic therapy significantly correlated with longer survival, demonstrating benefit in advanced cholangiocarcinoma. Thus, photodynamic therapy should be considered during therapeutic decision making in advanced cholangiocarcinoma.