How do phosphodiesterase-5 inhibitors affect cancer? A focus on glioblastoma multiforme

Area of Science:

• Oncology
• Pharmacology
• Neuroscience

Background:

• Overexpression of phosphodiesterase-5 (PDE5) in central nervous system (CNS) malignancies, including glioblastoma multiforme (GBM).
• PDE5 inhibitors are being investigated for repositioning as a therapeutic strategy for brain tumors.
• Existing research presents conflicting findings regarding the role of PDE5 and its inhibitors in GBM.

Purpose of the Study:

• To review and discuss the mechanisms of PDE5 inhibitors in cancer, with a focus on GBM.
• To provide an overview of current knowledge on PDE5 inhibitors for GBM treatment.
• To highlight the need for further research due to inconsistent preclinical findings.

Main Methods:

• Literature review of preclinical and clinical studies on PDE5 inhibitors in CNS malignancies.
• Analysis of the molecular mechanisms underlying the effects of PDE5 inhibitors on GBM.
• Discussion of the potential benefits and drawbacks of PDE5 inhibition in GBM therapy.

Main Results:

• PDE5 inhibitors can increase brain tumor permeability and enhance chemotherapy effectiveness.
• Potential antitumor functions include apoptosis induction, growth suppression, and immune modulation within the tumor microenvironment (TME).
• Contradictory evidence suggests a pro-oncogenic role for cyclic guanosine monophosphate (cGMP) in GBM, complicating therapeutic application.

Conclusions:

• The therapeutic value of PDE5 inhibitors in GBM remains uncertain due to conflicting preclinical data.
• Further investigation is crucial to elucidate the precise effects of PDE5 inhibitors, considering individual molecular heterogeneities in GBM.
• Additional studies are needed to guide the clinical application of PDE5 inhibitors for brain tumor treatment.