HPV-p53-miR-34a axis in HPV-associated cancers

Human papillomaviruses (HPVs) are known to cause many cancers by altering multiple signaling pathways through their oncogene integration into host genome and expression. Studies have shown that many microRNAs (miRs) may function as oncogenes (called as oncomiRs) to promote an oncogenic effect. MiR-34a among the reported oncomiRs is a key player in the carcinogenesis caused by infection with HPVs. In this mini-review, we summarise the roles of miR-34a in HPV-caused cancers. MiR-34a is transcriptionally regulated by tumour suppressor p53. HPV oncogene E6 inhibits expression of p53 to decrease the levels of miR-34a, leading to the increased expression of multiple genes which are targeted by miR-34a. The upregulation of these genes increases cancer cell proliferation, survival and migration in HPV-associated cancers.