Human papillomavirus-driven repression of NRF2 signalling confers chemo-radio sensitivity and predicts prognosis in head and neck squamous cell carcinoma

Purpose: To investigate the role of NRF2 signalling in conferring superior prognosis in patients with HPV positive (HPV+ve) head & neck squamous cell carcinomas (HNSCC) compared to HPV negative (HPV-ve) HNSCC and develop molecular markers for selection of HPV+ve HNSCC patients for treatment de-escalation trials.Methods: NRF2 activity (NRF2, KEAP1, and NRF2-transcriptional targets), p16, and p53 levels between HPV+ve HNSCC and HPV-ve HNSCC in prospective and retrospective tumor samples as well as from TCGA database were compared. Cancer cells were transfected with HPV-E6/E7 plasmid to elucidate if HPV infection represses NRF2 activity and sensitizes to chemo-radiotherapy.Results: Prospective analysis revealed a marked reduction in expression of NRF2, and its downstream genes in HPV+ve tumors compared to HPV-ve tumors. A retrospective analysis by IHC revealed significantly lower NQO1 in p16high tumors compared to p16low tumors and the NQO1 expression correlated negatively with p16 and positively with p53. Analysis of the TCGA database confirmed low constitutive NRF2 activity in HPV+ve HNSCC compared to HPV-ve HNSCC and revealed that HPV+ve HNSCC patients with 'low NQO1' expression showed better overall survival compared to HPV+ve HNSCC patients with 'high NQO1' expression. Ectopic expression of HPV-E6/E7 plasmid in various cancer cells repressed constitutive NRF2 activity, reduced total GSH, increased ROS levels, and sensitized the cancer cells to cisplatin and ionizing radiation.Conclusion: Low constitutive NRF2 activity contributes to better prognosis of HPV+ve HNSCC patients. Co expression of p16high, NQO1low, and p53low could serve as a predictive biomarker for the selection of HPV + ve HNSCC patients for de-escalation trials.

Automated summary

The role of NRF2 signalling in conferring superior prognosis in HPV+ve HNSCC patients and developing molecular markers for treatment selection was investigated. The study compared NRF2 activity, p16, and p53 levels between HPV+ve and HPV-ve tumors using prospective and retrospective samples, as well as the TCGA database. The results showed lower NRF2 activity in HPV+ve tumors, and HPV+ve HNSCC patients with low NQO1 expression had better overall survival. Ectopic expression of HPV-E6/E7 plasmid in cancer cells repressed NRF2 activity and sensitized the cells to cisplatin and radiation.