Targeting DNA Damage Response as a Strategy to Treat HPV Infections

Area of Science:

• Virology
• Oncology
• Molecular Biology

Background:

• Mucosotropic human papillomaviruses (HPVs) cause common anogenital infections with cancer-progression potential.
• Limited therapeutic options necessitate the identification of effective drug candidates for HPV infections.
• The HPV E7 protein drives viral DNA amplification by inducing S phase reentry and DNA damage response (DDR).

Purpose of the Study:

• To investigate the efficacy of DNA damage response (DDR) regulators inhibitors against HPV-18 infection using an organotypic raft culture system.
• To evaluate the impact of ATR/Chk1 and ATM/Chk2 inhibitors on HPV replication and cellular processes.
• To identify potential therapeutic agents for HPV infections and associated cancers.

Main Methods:

• Recapitulation of productive HPV-18 infection in organotypic raft cultures of primary human keratinocytes.
• Treatment of infected cultures with small molecule inhibitors of ATR/Chk1 and ATM/Chk2 pathways.
• Assessment of viral DNA amplification, S-phase reentry, DNA damage, apoptosis, and cell viability.
• Evaluation of MK-8776 efficacy in HPV-infected keratinocytes and cervical cancer cell lines, alone and in combination with cisplatin.

Main Results:

• Inhibitors of ATR/Chk1 and ATM/Chk2 impaired HPV-18 S-phase reentry, progression, and viral DNA amplification.
• The Chk1 inhibitor MK-8776 demonstrated potent antiviral activity, reducing HPV DNA amplification by 90-99%.
• MK-8776 induced DNA damage and apoptosis preferentially in HPV-infected cells, a sensitivity linked to the E7 protein, and also caused cell death in cervical cancer lines, sensitizing them to cisplatin.

Conclusions:

• Chk1 inhibitors, particularly MK-8776, show significant potential for treating HPV infections due to their ability to inhibit viral replication and induce cancer cell death.
• The HPV E7 protein mediates sensitivity to Chk1 inhibition, highlighting a specific vulnerability in HPV-driven cancers.
• Chk1 inhibitors represent promising candidates for repurposing as single or combination therapies against the spectrum of HPV infections and cervical cancer.