Androgen receptor functions as transcriptional repressor of cancer-associated fibroblast activation
Andrea Clocchiatti, Soumitra Ghosh, Maria-Giuseppina Procopio, Luigi Mazzeo, Pino Bordignon, Paola Ostano, Sandro Goruppi, Giulia Bottoni, Atul Katarkar, Mitchell Levesque, Peter Kölblinger, Reinhard Dummer, Victor Neel, Berna C. Özdemir, G. Paolo Dotto
Andrea Clocchiatti, Soumitra Ghosh, Maria-Giuseppina Procopio, Luigi Mazzeo, Pino Bordignon, Paola Ostano, Sandro Goruppi, Giulia Bottoni, Atul Katarkar, Mitchell Levesque, Peter Kölblinger, Reinhard Dummer, Victor Neel, Berna C. Özdemir, G. Paolo Dotto
View: Text | PDF
Research Article Dermatology Oncology

Androgen receptor functions as transcriptional repressor of cancer-associated fibroblast activation

Abstract

The aging-associated increase of cancer risk is linked with stromal fibroblast senescence and concomitant cancer-associated fibroblast (CAF) activation. Surprisingly little is known about the role of androgen receptor (AR) signaling in this context. We have found downmodulated AR expression in dermal fibroblasts underlying premalignant skin cancer lesions (actinic keratoses and dysplastic nevi) as well as in CAFs from the 3 major skin cancer types, squamous cell carcinomas (SCCs), basal cell carcinomas, and melanomas. Functionally, decreased AR expression in primary human dermal fibroblasts (HDFs) from multiple individuals induced early steps of CAF activation, and in an orthotopic skin cancer model, AR loss in HDFs enhanced tumorigenicity of SCC and melanoma cells. Forming a complex, AR converged with CSL/RBP-Jκ in transcriptional repression of key CAF effector genes. AR and CSL were positive determinants of each other’s expression, with BET inhibitors, which counteract the effects of decreased CSL, restoring AR expression and activity in CAFs. Increased AR expression in these cells overcame the consequences of CSL loss and was by itself sufficient to block the growth and tumor-enhancing effects of CAFs on neighboring cancer cells. As such, the findings establish AR as a target for stroma-focused cancer chemoprevention and treatment.

Authors

Andrea Clocchiatti, Soumitra Ghosh, Maria-Giuseppina Procopio, Luigi Mazzeo, Pino Bordignon, Paola Ostano, Sandro Goruppi, Giulia Bottoni, Atul Katarkar, Mitchell Levesque, Peter Kölblinger, Reinhard Dummer, Victor Neel, Berna C. Özdemir, G. Paolo Dotto

×

Figure 8

HDFs with reduced AR expression sustain melanoma cell growth in vivo.

Options: View larger image (or click on image) Download as PowerPoint
HDFs with reduced AR expression sustain melanoma cell growth in vivo. (A...
(A) SK-MEL-23 melanoma cells expressing a fluorescent indicator of cell cycle (GFP-FUCCI protein for S/G2 phases of the cell cycle) were admixed with HDFs with silenced AR versus control, followed by parallel injections into contralateral ears of NOD/SCID/IL2rg–/– mice (8–10 weeks old, females). Shown are representative images of combined bright-field and fluorescence microscopy of a pair of mouse ears, at 27 days after injection, with quantification of the green fluorescence intensity signal (intensity × surface area) at the indicated time points after signal normalization on day 1. Scale bar: 1 mm. Data are represented as mean ± SEM. n(tumor pairs) = 3; *P < 0.05, 2-tailed paired t test. (B) SK-MEL-28 melanoma cells expressing dsRed were admixed with HDFs with silenced AR versus control, followed by parallel injections into contralateral ears of NOD/SCID/IL2rg–/– mice (8–10 weeks old, male). Shown are representative images of combined bright-field and fluorescence microscopy of a pair of mouse ears, at 28 days after injection, with quantification of the red fluorescence intensity signal (intensity × surface area) at the indicated time points after injection after signal normalization on day 1. Scale bar: 1 mm. Data are represented as mean ± SEM. n(tumor pairs) = 5; ***P < 0.005, 2-tailed paired t test. (C and D) Immunofluorescence analysis for the MITF and Ki67 markers in lesions formed by SK-MEL-23 cells admixed with HDFs with or without AR silencing. Shown are representative images and quantification for 3 tumor pairs, examining at least 4 independent fields per lesion, using ImageJ software. Values are expressed as number of MITF-positive melanoma cells per square millimeter (C) and percentage of Ki67-positive cells (D). Data are represented as mean ± SD. n(tumor pairs) = 3; *P < 0.05, 2-tailed paired t test. Scale bars: 30 μm. Representative H&E staining and additional macrophage and angiogenesis markers are show in Supplemental Figure 6.