Coumarin has antitumour effects in vivo and cytostatic effects in vitro. Its half-life in humans is short (1-1.5 h) and the monohydroxylated biotransformation products have significantly longer half-lives. One or several of these products may thus be responsible for the antitumoral effects. We have assayed the in vitro cytostatic activity of five monohydroxylated coumarins (3-, 4-, 6-, 7- and 8-monohydroxycoumarin), their acetates and methyl-ethers. Murine melanoma cells (cell line B16-F10) and murine fibroblasts (B82) were exposed to the test compounds at concentrations between 10 and 160 microg/ml. The cytostatic effects were estimated by reduction of the tetrazolium dye MTT. In the melanoma cells, some of the compounds inhibited growth after exposure for 1 day. In contrast, coumarin inhibited growth to a smaller extent, and only after exposure for 3 days. The most active compounds (3-acetoxycoumarin, 4-methoxycoumarin and 6-hydroxycoumarin), as well as coumarin, were also assayed in murine fibroblasts. The cytostatic effects of 4-methoxycoumarin and 6-hydroxycoumarin were less pronounced in fibroblasts than in melanoma cells. Our observations suggest that these compounds may have a greater therapeutic margin.

This review article focuses on von Hippel–Lindau (VHL) disease, a rare genetic disorder characterized by the development of tumors and cysts throughout the body. It discusses the following aspects of the disease. Genetics: VHL disease is caused by mutations in the VHL tumor suppressor gene located on chromosome 3. These mutations can be inherited or occur spontaneously. This article details the different types of mutations and their associated clinical features. Pathophysiology: The underlying cause of VHL disease is the loss of function of the VHL protein (pVHL). This protein normally regulates hypoxia-inducible factors (HIFs), which are involved in cell growth and survival. When pVHL is dysfunctional, HIF levels become elevated, leading to uncontrolled cell growth and tumor formation. Clinical Manifestations: VHL disease can affect various organs, including the brain, spinal cord, retina, kidneys, pancreas, and adrenal glands. Symptoms depend on the location and size of the tumors. Diagnosis: Diagnosis of VHL disease involves a combination of clinical criteria, imaging studies, and genetic testing. Treatment: Treatment options for VHL disease depend on the type and location of the tumors. Surgery is the mainstay of treatment, but other options like radiation therapy may also be used. Challenges: This article highlights the challenges in VHL disease management, including the lack of effective therapies for some tumor types and the need for better methods to monitor disease progression. In conclusion, we emphasize the importance of ongoing research to develop new and improved treatments for VHL disease.