PDE5 inhibitors against cancer via mediating immune cells in tumor microenvironment: AI‐based approach for future drug repurposing exploration

Phosphodiesterase‐5 (PDE5) inhibitors are used clinically for the treatment of erectile dysfunction, pulmonary arterial hypertension, and other urological diseases. Emerging evidences have suggested the therapeutic capacity of PDE5 inhibitors as the repurposed drugs in oncology. However, the essential immune function of PDE5 inhibitors against cancer in tumor microenvironment (TME) remains unclear. This review aimed to summarize the recent advances regarding the repurposing of PDE5 inhibitors as anti‐cancer agents for cancer management to enhance the anti‐tumor immune response by mediating various immune cells, which included the myeloid‐derived suppressor cells, macrophages, T cells, fibroblasts, and natural killer cells in TME. Moreover, artificial intelligence (AI), as a new approach, is composed of traditional machine learning and deep learning methods and could be potentially used to identify the targets of immune cells in TME and predict the efficacy for repurposed drug toward malignancies. In summary, these endeavors provide novel insights into the comprehensive strategies for PDE5 inhibitors mediating immune cells against cancer and AI‐based approach for future drug repurposing exploration. Phosphodiesterase‐5 (PDE5) inhibitors are used clinically for the treatment of erectile dysfunction, pulmonary arterial hypertension, and other urological diseases. Emerging evidences have suggested the therapeutic capacity of PDE5 inhibitors as the repurposed drugs in oncology. However, the essential immune function of PDE5 inhibitors against cancer in tumor microenvironment (TME) remains unclear. This review aimed to summarize the recent advances regarding the repurposing of PDE5 inhibitors as anti‐cancer agents for cancer management to enhance the anti‐tumor immune response through mediating various immune cells, which included the myeloid‐derived suppressor cells (MDSCs), macrophages, T cells, fibroblasts, and natural killer (NK) cells in TME. Moreover, artificial intelligence (AI), as a new approach, is composed of traditional machine learning (ML) and deep learning (DL) methods and could be potentially used to identify the targets of immune cells in TME and predict the efficacy for repurposed drug toward malignancies. In summary, these endeavors provide novel insights into the comprehensive strategies for PDE5 inhibitors mediating immune cells against cancer and AI‐based approach for future drug repurposing exploration.