Epidemiological studies have shown that HPV-related diseases are the most prevalent sexually transmitted infections. In this context, this report will present various clinical cases demonstrating the effectiveness of Acyclovir (ACV) or its prodrug Valaciclovir (VCV), both acyclic guanosine analogs commonly used for the treatment of HHV-1 and HHV-2, for the treatment of HPV-related diseases. The report shows the remission of five cases of penile condyloma and a case of remission in a woman affected by cervical and vaginal condylomas and a vulvar giant condyloma acuminate of Buschke and Lowenstein. The literature review shows that ACV is effective in treating skin warts when administered orally, topically, and intralesionally, suggesting its therapeutic potential in other diseases associated with HPV. ACV was also used successfully as an adjuvant therapy for juvenile and adult forms of laryngeal papillomatosis, also known as recurrent respiratory papillomatosis, prolonging the patient’s symptom-free periods. Although the prevention of HPV infections is certainly achieved with the HPV vaccine, ACV and VCV have shown to be effective even against genotypes not included in the current vaccine and can be helpful for those problematic clinical cases involving unvaccinated individuals, immunocompromised patients, people who live with HIV, or non-responders to the vaccine. We and others concluded that randomized clinical trials are necessary to determine the efficacy of ACV and VCV for HPV-related diseases.

Despite the availability of excellent HPV-specific vaccines, HPV-related conditions and, notably, their related neoplastic diseases are expected to impact human health for many years to come. Polyphenols and flavonoids are a large class of natural products, credited with a wide range of pharmacological properties including antineoplastic activity. However, the currently available data depict a rather heterogeneous and sometimes contradictory landscape, and no univocal conclusions can be drawn. To shed light on such a controversial issue, a restricted list of promising polyphenols were evaluated for their antineoplastic activity on HPV-transformed cells. Among them, Kaempferol, Galangin, and Luteolin proved to have distinct anti-clonal activity with ID₅₀ values, respectively, of 1.25, 6.25, and 3.0 microMolar, and three other compounds, namely, Chrysin, Quercetin, and Apigenin, showed fair although less intense activity with ID values, respectively, of 25.0, 40, and 25 microMolar. Interestingly, a distinct anti-proliferative effect could also be suggested for Kaempferol, Luteolin, and Apigenine. Cooperative anti-clonal effects could be suggested for binary and ternary compositions made of Kaepferol, Galangin, and Luteolin once combined at concentrations ranging from 2 to 8 microMolar. At these concentrations, the single components and the triple combination induced distinct cell cycle modulation associated with marked restoration of the p53 and p21Cip1/Waf1 levels, consistent with the disruption of the E6/E6AP interaction whose continuous activity is necessary for both the induction and maintenance of the viral-induced neoplastic phenotype.

Human Papillomavirus-associated cancer remains a global health issue despite the availability of prophylactic vaccination. Two single-chain recombinant antibodies specific for the high-risk HPV16-E6 and E7 oncoproteins were previously developed as intrabodies in HPV16-positive cells. The anti-E6 I7NUC and anti-E7 43M2SD intrabodies demonstrated antiproliferative efficacy in vitro and in mouse tumor models by interfering with p53 and pRb tumor suppressors. This study aimed to explore the mechanism behind this antitumor activity. HPV16-positive SiHa cells were electroporated with the intrabody DNA plasmids and processed for RNA-seq analysis 6 h after transfection. Differential expression and functional analysis were conducted to identify significantly modulated genes and enriched pathways. RT-qPCR was employed to confirm the modulation of selected genes. The human interactome of E6 and E7, retrieved from BioGRID, was used to check for known interactions. The anti-E6 I7Nuc modulates 12,820 genes, of which 6,072 are upregulated and 6,748 downregulated, mainly encoding proteins that directly bind to HPV16E6. The anti-E7 43M2SD intrabody modulates 1,174 genes, mostly encoding proteins that interact indirectly with E7 binders. Notably, 3,191 genes in cells expressing I7NUC and 468 in those expressing 43M2SD are novel. The functional analysis revealed over 100 KEGG pathways significantly affected by I7NUC and only one pathway affected by 43M2SD. “Neuroactive ligand-receptor interaction, Proteasome, Nucleocytoplasmic transport, Protein processing in endoplasmic reticulum, Cell cycle, ATP-dependent chromatin remodelling, Cellular senescence, Ubiquitin-mediated proteolysis, Ribosome and Viral carcinogenesis” are the top significant pathways affected by I7NUC, with almost 100% down-modulated DEGs. 43M2SD affected only the “Viral protein interaction with cytokine and cytokine receptor” pathway, with CXCL6, 9, 10 and 11 genes all downregulated. I7NUC determines the transcriptional downregulation of Energy Metabolism pathway enzymes, including SLC2A1, SLC5A1, hexokinase1/2, LDHA, GLS2, SLC7A5, SLC7A11, HIF-1, and a significant percentage of transcripts associated with the phosphorylation-oxidative enzyme complexes. The anti-E6 and anti-E7 intrabodies interfere with cellular pathways essential for tumor transformation, confirming their great potential as therapeutic agents for HPV16-related diseases. The differences observed in the effects of the two intrabodies at the transcriptional level may be advantageous in clinical applications to different tumor types or grades of premalignant lesions.