gms | German Medical Science

Introduction: More than 25% of oropharygeal squamous cell carcinomas (OSCC) are associated with the human papilloma virus (HPV). Until today, there is no difference in therapy between HPV positive and HPV negative OSCCs, although there is strong clinical evidence that HPV associated OSCC respond much better to irradiation. In this study, we compared the radio sensitivity of HPV positive and negative OSCC cell lines.

Methods: Twelve immortal OSCC cell lines with known HPV status were irradiated with 2, 6 and 8 Gray (Gy). After irradiation, cell cycle analysis via flow cytometry and clonogenic survival tests via colony forming assay was performed.

Results: Irradiation of the OSCC cell lines revealed that HPV associated OSCC cell lines are more sensitive than HPV negative cell lines. The SF2 values (surviving fraction after 2 Gy) of the HPV positive OSCC cell lines were 71% in comparison to the HPV negative cell lines. In cell cycle analysis, irradiation with 2 and 6 Gy resulted in a time and dose dependent cell cycle arrest within all OSCC lines, but increased apoptosis could be measured in HPV positive cell lines.

Conclusion: We have shown that HPV positive OSCC cell lines have an increased radio sensitivity compared to HPV negative OSCC, which might be explained by specific cellular alterations within HPV positive OSCC. Resolving these specific molecular mechanisms might reveal new ways towards targeted therapy.