Camp efflux inhibition by nsaids: drug repositioning for pdac treatment

Abstract

In a previous work, we validated the inhibition of MRP4-dependant cAMP extrusion process as a promising therapeutic strategy for Pancreatic Ductal Adenocarcinoma (PDAC). In view of the therapeutic challenge associated with PDAC, we set out to search and characterize approved drugs that inhibit cAMP transport with the goal of establishing a repositioning strategy. Based on the results of this screening, we selected the Non-steroidal anti-inflammatory drugs (NSAIDs) as an interesting pharmacological family to inquire for rational drug repositioning. NSAIDs have been tested in the past as co-adjuvants in the therapy of various types of cancer, in many cases with positive results. Although their effects that depend on cyclooxygenase-2 inhibition are well described, the effects that are independent of this inhibition are far for being clear. We hypothesize that MRP4 inhibition could be a missing link in the overall action on tumor progression of these compounds. In this work, we measure the intracellular cAMP response upon treatment with 13 different NSAIDs using a technique developed in our laboratory in which we use HEK-293T cells stably transfected with the EPAC-SH187 sensor. Ibuprofen, acetyilsalicylic acid, Naproxen, Indomethacin, Diclofenac, Dexketoprofen and Ketorolac have shown to increase intracellular cAMP concentrations upon treatment (p<0.01). The concomitant significant reduction of extracellular cAMP upon treatment with these NSAIDs was also measured using a Radio-Binding Protein assay (RBP), which confirmed cAMP transport inhibition as one of the mechanisms that triggers intracellular cAMP increment (p<0.05). On the other hand, Celecoxib, Acetaminophen, Dipyrone, Phenacetin, Meloxicam and Piroxicam failed to increase intracellular cAMP upon treatment. These emerging results, together with an exhaustive literature search will allow us to select our repositioning