Pancreatic Cancer Cell Migration and Metastasis Is Regulated by Chemokine-Biased Agonism and Bioenergetic Signaling

Abstract

Patients with pancreatic ductal adenocarcinoma (PDAC) invariably succumb to metastatic disease, but the underlying mechanisms that regulate PDAC cell movement and metastasis remain little understood. In this study, we investigated the effects of the chemokine gene CXCL12, which is silenced in PDAC tumors yet is sufficient to suppress growth and metastasis when re-expressed. Chemokines like CXCL12 regulate cell movement in a biphasic pattern, with peak migration typically in the low nanomolar concentration range. Herein, we tested the hypothesis that the biphasic cell migration pattern induced by CXCL12 reflected a bias of agonist bioenergetic signaling that might be exploited to interfere with PDAC metastasis. In human and murine PDAC cell models, we observed that non-migratory doses of CXCL12 were sufficient to decrease oxidative phosphorylation and glycolytic capacity and to increase levels of phosphorylated forms of the master metabolic kinase AMPK. Those same doses of CXCL12 locked myosin light chain into a phosphorylated state, thereby decreasing F-actin polymerization and preventing cell migration in a manner dependent upon AMPK and the calcium-dependent kinase CAMKII. Notably, at elevated concentrations of CXCL12 that were insufficient to trigger chemotaxis of PDAC cells, AMPK blockade resulted in increased cell movement. In two preclinical mouse models of PDAC, administration of CXCL12 decreased tumor dissemination, supporting our hypothesis that chemokine-biased agonist signaling may offer a useful therapeutic strategy. Our results offer a mechanistic rationale for further investigation of CXCL12 as a potential therapy to prevent or treat PDAC metastasis.

On the use of peroxy-caged luciferin (PCL-1) probe for bioluminescent detection of inflammatory oxidants in vitro and in vivo – Identification of reaction intermediates and oxidant-specific minor products

“…This in turn may provide a better approach to increase the efficiency of cancer immunotherapy and/or combination of redox modulators with the standard-of-care drugs. Typically tumor growth is assessed by measuring the intensity of bioluminescence signal (light intensity) in luciferase-transfected cancer cell mice xenografts [30]. The substrate, luciferin, is injected as needed and the green bioluminescent signal intensity from the luciferase-transfected tumor cells is measured [30].…”

“…Typically tumor growth is assessed by measuring the intensity of bioluminescence signal (light intensity) in luciferase-transfected cancer cell mice xenografts [30]. The substrate, luciferin, is injected as needed and the green bioluminescent signal intensity from the luciferase-transfected tumor cells is measured [30]. Using the PCL-1 probe, one can monitor in vivo bioluminescence imaging of tumor-derived ROS/RNS.…”

Mitochondria-Targeted Analogues of Metformin Exhibit Enhanced Antiproliferative and Radiosensitizing Effects in Pancreatic Cancer Cells

“…Six to eight-week-old C57BL/6 mice were anesthetized with isoflurane and were injected with 1×10 6 luciferase-expressing FC-1242 (FC-1242-luc) cells (24). To generate FC-1242-luc cells, the firefly luciferase gene was cloned into the mammalian expression vector pcDNA3.1/hygro(−) cells transfected using the Lipofectamine 2000 transfection reagent (Life Technologies).…”

“…A stable FC-1242-luc clone was expanded to generate a frozen stock. Cells were pretreated for 48 h with Met (1 mM) or Mito-Met 10 (0.5 μM) and then orthotopically engrafted to the pancreas as described previously (24-26). Starting the day of implantation, mice were treated daily with 1 mg/kg Met or Mito-Met 10 administered via an intraperitoneal injection in a 200 μL volume.…”

Diacylglycerol Kinase ζ (DGKζ) and Casitas b-Lineage Proto-Oncogene b–Deficient Mice Have Similar Functional Outcomes in T Cells but DGKζ-Deficient Mice Have Increased T Cell Activation and Tumor Clearance

“…1×10 6 KPC1242 tumor cells were injected orthotopically into the pancreas as previously described (26). 15 days later, mice were euthanized, tumor weight was measured, and T cells in the spleen, ascites and tumor were analyzed.…”