Would the Development of a Multitarget Inhibitor of 3CL^pro and TMPRSS2 be Promising in the Fight Against SARS-CoV-2?

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2), responsible for generating COVID-19, has spread worldwide and was declared a pandemic by the World Health Organization (WHO) on 11 March 2020, being responsible for various damages to public health, social life, and the economy of countries. Its high infectivity and mutation rates have stimulated researchers and pharmaceutical companies to search for new therapies against this disease. These efforts resulted in several vaccines and the identification of Molnupiravir as an oral treatment for this disease. However, identifying new alternatives and critical information is necessary to fight against this devastating agent. The findings in recent years regarding the structure and biochemistry of SARS-CoV2 are remarkable. In anti-CoV drug discovery, various targets, such as structural, non-structural, and hostrelated proteins are explored. In fact, 3CL^pro is the most used among non-structural proteins since this protease cleaves peptide sequences after the glutamine residue, and no human protease has this function. This makes this macromolecule an excellent drug target for discovering new compounds. Another promising target is the transmembrane protease serine 2 (TMPRSS2). Recent studies point to TMPRSS2 as one of the main targets responsible for viral entry related to the cleavage of the S protein. Similar to cathepsins, TMPRSS2 is also responsible for cleaving the spike protein SARS-CoV2, which binds to the ACE2 receptor. Thus, TMPRSS2 is one of the targets that may represent new alternatives in treating SARS-CoV2. In this context, would discovering a multitarget inhibitor be the new strategy in searching for drugs against SARS-CoV2? For many years, new drug discovery was based on the "one drug, one target" premise, where the biological action is related to interactions with only one biological target. However, this paradigm has been overcome as new evidence of multiple mechanisms of action for a single drug. Finally, this review will present a perspective on drug design based on a multitarget strategy against 3CL^pro and TMPRSS2. We hope to provide new horizons for researchers worldwide searching for more effective drugs against this devastating agent.