AdipoRon Modulation of the Invasive Potential of Prostate Cancer Cells Is Dependent on Their EMT-Related Phenotype

Background/Objectives: The epithelial-to-mesenchymal transition (EMT) process provides cancer cells with morpho-functional characteristics for invasion and metastasis. A reduction in serum adiponectin (APN) has been detected in prostate cancer (PCa) patients. Since AdipoRon (AdR), an agonist of APN, has been demonstrated to exert potent antitumor effects on cancer cells, including PCa, we explored the effects of AdR on PCa cells with different EMT-related traits. Methods: DU145 and PC3 cells were grown in 3D spheroids and treated with AdR or left untreated (CT). The expression of APN receptors, EMT markers, and invasive potential were analyzed using an integrated molecular and morphological approach. Results: APN receptor mRNA levels were higher in DU145 than in PC3 cells and were markedly increased only in DU145 spheroids upon AdR administration, while remaining unchanged in PC3 spheroids. AdR treatment was associated with MAPK signaling activation and modulation by AdR only in DU145 spheroids. Molecular and morphological analysis confirmed the "more epithelial" phenotype of DU145, compared with the "more mesenchymal" PC3 cells with higher N-cadherin expression, and EMT markers were not broadly affected by AdR administration in either cell line. MMP-2 activity was similar across experimental conditions, whereas MMP-9 activity was higher in PC3 than in DU145 spheroids and was not directly modulated by AdR. Although TIMP-2 mRNA levels were similar in the different experimental conditions, TIMP-1 mRNA and protein levels were higher in PC3 than in DU145 spheroids, and AdR increased TIMP-1 protein expression in PC3 cells. However, the MMP-2/TIMP-2 ratio strongly decreased in both AdR-treated DU145 and PC3 spheroids, compared with the CT, and a similar modulation for MMP-9/TIMP-1 was limited to DU145 cells. Conclusions: Overall, our results suggest that AdR activity can be associated with the modulation of invasion-associated molecular features of PCa spheroids, depending on their EMT-related phenotype.