General Assessment of Indole Derivatives and Wnt Pathway as Potential Key Factors Against Various Diseases, with Particular Emphasis on Thyroid Tumors

Indoles are chemical compounds that naturally occur in Prokaryotes and Eukaryotes. For example, indole alkaloids mainly occur in plant families such as Nyssaceae, Rubiaceae, Apocynaceae, and Loganiaceae. The popularity of indoles has led to further research into their function and synthetic modification. Meanwhile, the Wnt (Wingless and Int-1) signaling pathway is responsible for cell regulatory processes, while its dysfunction often constitutes the molecular basis for the pathogenesis of neoplastic processes. Databases such as PubMed, Scopus, Google Scholar, and Science Direct were used to perform a literature search with keywords including “indoles” and those related to their biological activity, as well as “Wnt pathway” and “thyroid cancer (TC)”. We used ClinicalTrials.gov to search current clinical trials for selected indoles, such as melatonin, indole-3-propionic acid, and indole-3-carbinol. While indoles possess many therapeutic properties, we focused here on the following: antitumor, antiviral, anti-inflammatory, antidepressant, antimigraine, antiemetic, and antihypertensive activities. We analyzed the Wnt pathway and its disruptions in thyroid cancer. In this manuscript, seventy-six (76) indoles, which have natural and synthetic origins, are presented. In addition to all activities mentioned, we discuss the therapeutic goals of indole applications in anticancer research. The Wnt signaling pathway can be changed in tumor cells, and such disruptions can occur in thyroid cancers.