Shamanth D Harishkumar, Shuaib Pasha, Rosemary Edwin, Sahana Madashetty, Bhargav Shreevatsa, Shiva Prasad Kollur, Chandan Shivamallu, Chandan Dharmashekar
Adenosine represents a promising drug repurposing candidate for further investigation as a modulator of the HPV E6-p53 interaction, exhibiting favorable computational and preliminary in vitro profiles. However, adenosine's short plasma half-life and complex receptor-mediated effects present major translational barriers, and direct biochemical evidence of p53 stabilization is still required to confirm this mechanism. Further mechanistic and translational studies are warranted to establish its therapeutic efficacy and clinical applicability.
BACKGROUND: High-risk HPV infection initiates cervical cancer through E6-mediated degradation of the p53 tumor suppressor protein via the ubiquitin-proteasome system, leading to apoptotic failure and genomic instability. No FDA-approved therapies currently target HPV E6, representing a significant unmet clinical need. This study aimed to identify repurposable compounds predicted to engage the p53 interface disrupted by E6-mediated proteasomal degradation, as a starting point for future p53-stabilisation studies.
METHODS: An integrated computational and experimental repurposing strategy was applied, encompassing network pharmacology, molecular docking, density functional theory (DFT), in silico ADMET profiling, and 500 ns molecular dynamics simulations. Network analysis was used to identify the primary hub protein targeted by HPV E6. Candidate compounds were screened for binding affinity against p53 chains C and D within the HPV16-associated degradation complex (PDB: 4XR8). In vitro validation was conducted by antioxidant, anti-inflammatory, anti-angiogenic, and cytotoxicity assay was assessed in SiHa (HPV16-positive) cells.
RESULTS: Network analysis confirmed TP53 as the principal hub disrupted by the HPV E6 protein. Among all screened compounds, adenosine demonstrated the highest binding affinities against p53 chains C and D (-6.318 kcal/mol and -7.104 kcal/mol, respectively), suggesting a stabilizing interaction at the p53 interface. DFT calculations revealed moderate electronic stability, with a HOMO-LUMO frontier orbital energy gap of 5.399 eV. ADMET profiling indicated an acceptable pharmacokinetic profile, and molecular dynamics simulations showed lower RMSD and RMSF fluctuations compared to doxorubicin over 500 ns. In vitro assays demonstrated dose-dependent cytotoxicity against SiHa cells (IC50 = 20.6 µg/mL), alongside antioxidant, anti-inflammatory, and anti-angiogenic activities.
CONCLUSION: Adenosine represents a promising drug repurposing candidate for further investigation as a modulator of the HPV E6-p53 interaction, exhibiting favorable computational and preliminary in vitro profiles. However, adenosine's short plasma half-life and complex receptor-mediated effects present major translational barriers, and direct biochemical evidence of p53 stabilization is still required to confirm this mechanism. Further mechanistic and translational studies are warranted to establish its therapeutic efficacy and clinical applicability.