Background: High-risk human papillomavirus (HR-HPV) persistent infection is the main cause of
cervical cancer and its precancerous lesions. A previous study showed that HPV16 and HPV58 infections were
the most common infection types in the local region. Some studies also declared that HPV58 E7 variants
increased the risk of cervical cancer among Asian populations.
Objective: This study aimed to determine whether the HPV58 E7 T20I (C632T) variant promotes the malignant
behavior of cervical cancer cells and the underlying mechanism of the HR-HPV E7 oncoprotein involved in the
development of cervical cancer.
Methods: CCK-8 and clone formation assays were used to detect cell proliferation ability. Transwell assays and
cell wound healing assays were used to evaluate cell migration ability. Targeted knockdown of E2F1 expression
using specific siRNA, RT-qPCR and Western blot were performed to assess gene expression changes. A
chromatin immunoprecipitation assay was used to verify that E2F1 interacted with the TOP2A promoter region.
Results: HPV58 E7 and HPV58 E7M oncoproteins increased the proliferation and migration ability of cervical
cancer cells. However, the HPV58 E7 T20I variant did not promote malignant behaviors compared with wildtype
HPV58 E7. HPV E7 and E7M oncoproteins increased the expression of TOP2A, BIRC5 and E2F1, and
knockdown of HPV E7 decreased their expression. Low E2F1 expression reduced the expression of TOP2A and
BIRC5 and inhibited the proliferation and migration ability of cervical cancer cells. E2F1 interacted with the
TOP2A gene promoter region to promote its transcriptional expression.
Conclusion: The HPV58 E7 T20I variant did not promote malignant behaviors compared with wild-type HPV58
E7. The HR-HPV E7 oncoprotein enhanced the proliferation and migration of cervical cancer cells, which was
considered to be due to the HPV E7 oncoprotein, increasing the expression of BIRC5 and TOP2A by
upregulating the transcription factor E2F1.