Topical Diclofenac Reprograms Metabolism and Immune Cell Infiltration in Actinic Keratosis

Abstract

Background: Melanoma and squamous cell carcinoma of the skin are characterized by an altered glucose metabolism, but little is known about metabolic changes in precancerous skin lesions such as actinic keratosis (AK). Here, we studied the central carbon metabolism and immune cell infiltrate of actinic keratosis lesions before, under, and 4 weeks after treatment with topical diclofenac (Solaraze®). Methods: This study was designed as a prospective, randomized, controlled, monocentric investigation ( ClinicalTrials.gov Identifier: NCT01935531). Myeloid and T cell infiltration was analyzed in skin biopsies from 28 patients by immunohistochemistry. Furthermore, immune cell activation was determined via quantitative real-time PCR ( IFN- γ, IL-10, CSF1, TGF- β , IL-6 ). Glucose, amino acid and Krebs' cycle metabolism was studied by mass spectrometry prior, during and after treatment with topical diclofenac. Biopsies from sun-exposed, untreated, healthy skin served as controls. Results: Increased lactate and decreased glucose levels suggested accelerated glycolysis in pre-treatment AK. Further, levels of Krebs' cycle intermediates other than citrate and amino acids were elevated. Analysis of the immune infiltrate revealed less epidermal CD1a+ cells but increased frequencies of dermal CD8+ T cells in AK. Treatment with diclofenac reduced lactate and amino acid levels in AK, especially in responding lesions, and induced an infiltration of dermal CD8+ T cells accompanied by high IFN- γ mRNA expression, suggesting improved T cell function. Discussion: Our study clearly demonstrated that not only cancers but also pre-malignant skin lesions, like AK, exhibit profound changes in metabolism, correlating with an altered immune infiltrate. Diclofenac normalizes metabolism, immune cell infiltration and function in AK lesions, suggesting a novel mechanism of action.

Restricting Glycolysis Preserves T Cell Effector Functions and Augments Checkpoint Therapy

“…Anti-tumor activity of diclofenac has been reported, and clinical trials were claimed (Pantziarka et al, 2016). We recently showed that topical administration of diclofenac in actinic keratosis, a pre-cancerous skin lesion, reduced lactate levels and increased IFNg expression in responders (Singer et al, 2019). In line with this, the data of this study suggest that the main impact of diclofenac on checkpoint therapy is the upregulated IFNg expression in T and NK cells.…”

“…In support of this notion, a high glycolytic index negatively correlated with progression-free survival in cancer patients treated with anti-PD1 therapy. As diclofenac targets glucose metabolism not only in murine tumor models and cell lines but also in patients with actinic keratosis (Gottfried et al, 2013;Singer et al, 2019), we tested its impact on the efficacy of checkpoint therapy.…”

Metabolism of pancreatic cancer: paving the way to better anticancer strategies

“…For instance, ivosidenib, an inhibitor of IDH1, improves the complete remission rate of IDH1-mutated acute myeloid leukemia with a low frequency of treatmentrelated adverse events in a phase I clinical trial that enrolled 258 patients [206]. In a phase IV clinical trial that enrolled 28 patients, the mechanism of diclofenac in effectively relieving actinic keratosis (a premalignant skin lesion) was well demonstrated, and the effect was largely dependent on modulating the metabolism of local lesions [207]. However, given the heterogeneity of different cancers, successful clinical applications in other cancers cannot be directly and simply applied to treating pancreatic tumors.…”

Regenerative Wound Dressings for Skin Cancer

“…Diclofenac (2-(2-(2,6-dichlorophenylamino)phenyl)acetic acid, Figure 1 ), also known for its sodium salt sold as Voltaren, is a non-steroidal anti-inflammatory drug widely used for actinic keratosis treatment and can be an adjuvant for basal cell carcinoma, squamous cell carcinoma, and melanoma skin metastases therapy [ 35 , 49 , 50 ].…”

“…Its mechanism of action, although not completely elucidated, could involve the inhibition of cyclooxygenase-1 and -2, enzymes involved in reducing prostaglandin formation from arachidonic acid, which reduces PGE2 synthesis and dysplastic keratinocytes in cancerous lesions [ 31 , 35 , 50 , 51 ]. Additionally, it might interfere with the SHH and Wnt signaling and lead to cancer cell apoptosis and inhibit angiogenesis and proliferation [ 31 , 35 , 50 ].…”