Antiproliferative effects of octadecyloxyethyl 9-[2-(phosphonomethoxy)ethyl]guanine against Me-180 human cervical cancer cells in vitro and in vivo

Small Molecule Inhibitors of Human Papillomavirus: A Review of Research from 1997 to 2021

Human papillomavirus (HPV) infections are the cause of warts, lesions and cancer, with different types of HPV causing different symptoms. HPV infections are the primary cause of cervical cancer. There are over 220 different types of HPV, and only nine of these can currently be vaccinated. There is a need to treat these viral infections without just treating the symptoms of the infection, as is currently the main method. There is a wide range of small molecules that have been used to inhibit various stages of the HPV infectious cycle. This review examined 132 small molecules from 121 studies that specifically target aspects of HPV infections. HPV DNA encodes for six early genes (E1 to E7, skipping E3) and two late genes (L1 and L2). According to the results, these targets for small molecule inhibitors fall into three categories: those targeting E1 and E2, targeting E6 and E7 and, finally, targeting L1 and L2. Inhibitors of E6 and E7 are the most widely studied targets, with the majority of HPV inhibition in this area. While compounds targeting both E1/E2 and E6/E7 have made it to clinical trials, there has been no significant advancement on the topic.

Overview of Biologically Active Nucleoside Phosphonates

The use of the phosphonate motif featuring a carbon-phosphorous bond as bioisosteric replacement of the labile P–O bond is widely recognized as an attractive structural concept in different areas of medicinal chemistry, since it addresses the very fundamental principles of enzymatic stability and minimized metabolic activation. This review discusses the most influential successes in drug design with special emphasis on nucleoside phosphonates and their prodrugs as antiviral and cancer treatment agents. A description of structurally related analogs able to interfere with the transmission of other infectious diseases caused by pathogens like bacteria and parasites will then follow. Finally, molecules acting as agonists/antagonists of P2X and P2Y receptors along with nucleotidase inhibitors will also be covered. This review aims to guide readers through the fundamentals of nucleoside phosphonate therapeutics in order to inspire the future design of molecules to target infections that are refractory to currently available therapeutic options.

Insights into the mechanism of action of cidofovir and other acyclic nucleoside phosphonates against polyoma- and papillomaviruses and non-viral induced neoplasia

Acyclic nucleoside phosphonates (ANPs) are well-known for their antiviral properties, three of them being approved for the treatment of human immunodeficiency virus infection (tenofovir), chronic hepatitis B (tenofovir and adefovir) or human cytomegalovirus retinitis (cidofovir). In addition, cidofovir is mostly used off-label for the treatment of infections caused by several DNA viruses other than cytomegalovirus, including papilloma- and polyomaviruses, which do not encode their own DNA polymerases. There is considerable interest in understanding why cidofovir is effective against these small DNA tumor viruses. Considering that papilloma- and polyomaviruses cause diseases associated either with productive infection (characterized by high production of infectious virus) or transformation (where only a limited number of viral proteins are expressed without synthesis of viral particles), it can be envisaged that cidofovir may act as antiviral and/or antiproliferative agent. The aim of this review is to discuss the advances in recent years in understanding the mode of action of ANPs as antiproliferative agents, given the fact that current data suggest that their use can be extended to the treatment of non-viral related malignancies.