Human papillomavirus 16 infection alters the Toll-like receptors and downstream signaling cascade: A plausible early event in cervical squamous cell carcinoma development.

Objective: Toll-like receptors constitute an important component of innate immune mechanism. HPV is a known etiological factor of cervical cancer and is known to interfere with the expression of TLRs and downstream signaling pathway. It remains poorly understood whether HPV modulates the expression of TLRs. Hence, understanding HPV mediated immune alterations might aid in identifying novel therapeutic targets. The aim was to study the relative gene expression of TLRs & downstream signaling pathway in cervical carcinoma.

Methods: Cervical squamous cell carcinoma (CSCC) and normal cervical tissues were obtained. Subsequent to HPV genotyping, mRNA expression profiling using PCR Array was performed. Protein expression of relevant genes with western blot was studied. Levels of cytokines in cervicovaginal washes were estimated using a Luminex multiplex platform.

Results: All cases of cervical cancer were HR-HPV positive and predominant subtype was HPV16 (71.1%). Significant TLR4 upregulation and TLR2,7 downregulation were observed in HR-HPV infected cervix. TLR4,7 demonstrated low expression in CSCC. Molecules from cancer allied pathways; RELA, AKT, CDKN2A, and MDM2 demonstrated upregulation in CSCC. Protein expression data corroborated with gene expression profile. A diminished level of Th1 cytokines TNF-α, IFN-ɣ, IL-17, and IL-12 was observed in CSCC. Significantly increased levels of IL-1β, IL-6 and IL-2 were detected in HR-HPV infected cervix. Kaplan Meier curve demonstrated high TLR4 and low TLR7 expression was associated with poor prognosis.

Conclusion: The study demonstrates the HPV mediated dampening of the innate immune response in CSCC and provides support for exploring potential TLR2, 7 agonists as an adjunct therapy in CSCC patients.