Safety and Immunogenicity of a Human Papillomavirus Peptide Vaccine (CIGB-228) in Women with High-Grade Cervical Intraepithelial Neoplasia: First-in-Human, Proof-of-Concept Trial

Objective. CIGB-228 is a novel therapeutic vaccine consisting of HLA-restricted HPV16 E7 epitope adjuvated with VSSP. This trial was designed to evaluate the toxicity, safety, immunogenicity, HPV clearance, and lesion regression. Methods. Seven women were entered. All were HLA-A2 positive, had biopsy-proven high-grade CIN, histologically positive for HPV16, and beared persistent postbiopsy lesions visible by digital colposcopy. HLA-A2 women with biopsy-proven high-grade CIN, HPV16-positive, and beared persistent postbiopsy lesions visible by digital colposcopy were vaccinated. One weekly injections of CIGB-228 vaccine was given for four weeks. Then, loop electrosurgical excision procedure (LEEP) of the transformation zone was performed. Study subjects were followed for 1 year after LEEP. Results. No toxicity beyond grade 1 was observed during and after the four vaccinations. Five of seven women had complete and partial regression. Cellular immune response was seen in all patients. HPV was cleared in three of the patients with complete response. Conclusion. CIGB-228 vaccination was well tolerated and capable to induce IFNγ-associated T-cell response in women with high-grade CIN. In several patients, lesion regression and HPV clearance were observed

The interesting relationship between APOBEC3 deoxycytidine deaminases and cancer: a long road ahead

Cancer is considered a group of diseases characterized by uncontrolled growth and spread of abnormal cells and is propelled by somatic mutations. Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) family of enzymes are endogenous sources of somatic mutations found in multiple human cancers. While these enzymes normally act as an intrinsic immune defence against viruses, they can also catalyse ‘off-target’ cytidine deamination in genomic single-stranded DNA intermediates. The deamination of cytosine forms uracil, which is promutagenic in DNA. Key factors to trigger the APOBEC ‘off-target’ activity are overexpression in a non-normal cell type, nuclear localization and replication stress. The resulting uracil-induced mutations contribute to genomic variation, which may result in neutral, beneficial or harmful consequences for the cancer. This review summarizes the functional and biochemical basis of the APOBEC3 enzyme activity and highlights their relationship with the most well-studied cancers in this particular context such as breast, lung, bladder, and human papillomavirus-associated cancers. We focus on APOBEC3A, APOBEC3B and APOBEC3H haplotype I because they are the leading candidates as sources of somatic mutations in these and other cancers. Also, we discuss the prognostic value of the APOBEC3 expression in drug resistance and response to therapies.</jats:p

DataSheet1_Similar deamination activities but different phenotypic outcomes induced by APOBEC3 enzymes in breast epithelial cells.PDF

APOBEC3 (A3) enzymes deaminate cytosine to uracil in viral single-stranded DNA as a mutagenic barrier for some viruses. A3-induced deaminations can also occur in human genomes resulting in an endogenous source of somatic mutations in multiple cancers. However, the roles of each A3 are unclear since few studies have assessed these enzymes in parallel. Thus, we developed stable cell lines expressing A3A, A3B, or A3H Hap I using non-tumorigenic MCF10A and tumorigenic MCF7 breast epithelial cells to assess their mutagenic potential and cancer phenotypes in breast cells. The activity of these enzymes was characterized by γH2AX foci formation and in vitro deamination. Cell migration and soft agar colony formation assays assessed cellular transformation potential. We found that all three A3 enzymes had similar γH2AX foci formation, despite different deamination activities in vitro. Notably, in nuclear lysates, the in vitro deaminase activity of A3A, A3B, and A3H did not require digestion of cellular RNA, in contrast to that of A3B and A3H in whole-cell lysates. Their similar activities in cells, nonetheless, resulted in distinct phenotypes where A3A decreased colony formation in soft agar, A3B decreased colony formation in soft agar after hydroxyurea treatment, and A3H Hap I promoted cell migration. Overall, we show that in vitro deamination data do not always reflect cell DNA damage, all three A3s induce DNA damage, and the impact of each is different.</p

Obtaining a Vaccine Candidate Against Tumors Expressing the E7 Antigen of Human Papillomavirus type 18

Abstract Background: Cervical cancer is the fourth most common cancer in women worldwide and was the leading cause of death among approximately 300 000 cases in 2018. The main risk factor for developing this disease is the persistent infection of high-risk types of human papillomavirus (HPV); specifically HPV-18 is recognized as one of the major contributors for adenocarcinoma and squamous cancer. There are three prophylactic vaccines to prevent infection by HPV, but these vaccines are not effective in infected people. On the other hand, despite the success of various types of therapeutic vaccine candidates in clinical trials, none of them is commercially available to treat women with HPV-related malignancies. As the methods used for obtaining those therapeutic candidates are awfully expensive, they could be inaccessible for developing countries. In this scenario, E7 antigen of HPV is considered and ideal target for developing therapeutic vaccines. In accordance with this, the aim of this work is to obtain a vaccine candidate with high levels of purity through a profitable process, for treating tumors expressing the E7 antigen of HPV-18.Results: We have obtained the novel therapeutic vaccine candidate CIGB550-E718 that comprises the fusion between an E7 mutein of HPV-18 and the cell-penetrating peptide with immunostimulatory properties CIGB550. The expression of the fusion protein evaluated using two strains of E. coli and 16 culture media with different composition enabled us to choose the best setting in which the interest protein accounted for approximately 16% of the total cellular protein. The best results were obtained using BL21(DE3) cells as host system grown in a culture medium containing M9 salt, casein hydrolysate and glycerol as a carbon source. The recombinant protein was purified by a single affinity chromatographic step up to 90% purity. Yields of 32 mg of the CIGB550-E718 per liter of culture were achieved from 2.5 L scale.Conclusions: These results are a promising and cost-effective approach for the future production and scale-up of the protein CIGB550-E718, which could be a therapeutic alternative for treating women with lesions associated to HPV-18 infection. </jats:p