Significance of multiple HPV infection in cervical cancer patients and its impact on treatment response.

Human papilloma virus (HPV) is the major cause of invasive cervical cancer (ICC). The study aim was to determine the prevalence of HPV genotypes and to correlate HPV types with response to radiotherapy. A total of 43 cervical biopsies collected from sequentially enrolled patients were analyzed by DNA amplification with MY09/MY11 primers and sequenced to determine the HPV genotype. Samples with multiple infections were resolved by multiplex PCR, combined with array primer extension (APEX). HPV DNA was detected in 40 of 43 (93%) samples. Nine different HPVs, including the most common types -16 (53%) and -18 (13%) were detected. Other types were HPV 31, 33, 45, 52, 58, 66 and 68. Single HPV types were found in 33 of 40 samples (82%) and multiple types in 7 of 40 samples (18%). The following significant predictors were identified: a) HPV 58 was most significant (p=0.02), followed by HPV 18 (p=0.04) associated with lack of treatment response; b) tumor size (p=0.042) and treatment response (p=0.025) elicited association with HPV infection type; c) treatment failure were found to be nearly 5-fold higher in case of multiple infections than of single infection (57% versus 12%) (odds ratio = 9.66; 95% CI 1.6-6.00). d) Multiple HPV infections correlated most prominently with lack of treatment compared with single type infection (p=0.005). Hence, patients with multiple infections, large tumor size, and HPV 58 and/or 18, are at risk of treatment failure and need to be followed for response and suitable inter-ventions done for a favorable outcome.

Intracellular anti-E7 human antibodies in single-chain format inhibit proliferation of HPV16-positive cervical carcinoma cells.

The E7 tumor antigen of human papillomavirus type 16 (HPV16) is a validated target for immunodiagnosis and immunotherapy of HPV-associated cervical cancer. Anti-HPV16 E7 antibodies in scFv format were isolated from a human antibody phage display library and characterized. With the aim of interfering with the oncogenic activity of E7 protein, the most reactive of the selected antibody fragments was expressed by eukaryotic vectors in different compartments of the HPV16-positive cervical carcinoma SiHa cell line. The intracellular antibodies (intrabodies) were tested for their ability of inhibiting cell proliferation. A significant inhibition was obtained targeting the intrabodies to the nuclear and secretory compartments whereas no significant effect was observed in case of cytoplasmic localization. Inhibition was highly specific as no antiproliferative effect was obtained either with the E7-specific intrabodies in HPV-negative cells nor with irrelevant intrabodies in SiHa cells.

Plant-derived human papillomavirus 16 E7 oncoprotein induces immune response and specific tumor protection.

Vaccine strategies for treatment of human papillomavirus-induced cervical cancer are based on either the recombinant E7 fusion oncoprotein or E7 CTL peptides. The therapeutic potential of the E7-based vaccine depends on the use of different adjuvants. In this study, we describe for the first time the expression of the human papillomavirus 16 E7 protein in Nicotiana benthamiana plant using a potato virus X-derived vector. C57BL/6 mice immunized with E7-containing crude foliar extracts developed both humoral and cell-mediated immune responses and were protected from tumor development after challenge with the E7-expressing C3 tumoral cell line. Our data support the possibility of producing a cost-effective anticancer vaccine in plant with intrinsic adjuvant-like properties.