Death receptors and mitochondria: life depends on the liver

Natural epidithiodiketopiperazine alkaloids as potential anticancer agents: Recent mechanisms of action, structural modification, and synthetic strategies

Cancer has become a grave health crisis that threatens the lives of millions of people worldwide. Because of the drawbacks of the available anticancer drugs, the development of novel and efficient anticancer agents should be encouraged. Epidithiodiketopiperazine (ETP) alkaloids with a 2,5-diketopiperazine (DKP) ring equipped with transannular disulfide or polysulfide bridges or S-methyl moieties constitute a special subclass of fungal natural products. Owing to their privileged sulfur units and intriguing architectural structures, ETP alkaloids exhibit excellent anticancer activities by regulating multiple cancer proteins/signaling pathways, including HIF-1, NF-κB, NOTCH, Wnt, and PI3K/AKT/mTOR, or by inducing cell-cycle arrest, apoptosis, and autophagy. Furthermore, a series of ETP alkaloid derivatives obtained via structural modification showed more potent anticancer activity than natural ETP alkaloids. To solve supply difficulties from natural resources, the total synthetic routes for several ETP alkaloids have been designed. In this review, we summarized several ETP alkaloids with anticancer properties with particular emphasis on their underlying mechanisms of action, structural modifications, and synthetic strategies, which will offer guidance to design and innovate potential anticancer drugs.

A new era in the treatment of chronic hepatitis C infection

Treatment of chronic hepatitis C virus (HCV) infection has evolved over the past three decades. At the start, treatment involved interferon monotherapy followed by combination therapy using interferon and ribavirin, and subsequently evolved to pegylated interferon (Peg-IFN) and ribavirin. In genotype 1 infection, rates of sustained virological response (SVR) are approximately 45 % with Peg-IFN and ribavirin, whereas SVR rates in genotypes 2 and 3 infections are as high as 70 % to 80 %. Side effects and cost related to these drugs are important concerns, particularly in countries like India where patients have to bear their health expenses. In the recent past, there has been a significant change in course with the on-going search and the development of more effective drugs in the management of HCV infection. Telaprevir and Boceprevir are two new potent protease inhibitors (direct acting antiviral or DAA agents) which, when administered with Peg-IFN and ribavirin, have shown to result significantly higher SVR rates in phase 3 studies in patients with genotype 1 infection, both in treatment naïve patients (up to 75 %) and those with previously failed therapy. Several other new antiviral agents some in combination with Peg-IFN and ribavirin and some in combination without Peg-IFN (IFN-free regimens) are currently being tested in patients with genotype 1, 2 and 3 infections and are expected to dramatically change the armamentarium of HCV therapy in the coming years.

Curcumin and liver disease

Liver diseases pose a major medical problem worldwide and a wide variety of herbs have been studied for the management of liver-related diseases. In this respect, curcumin has long been used in traditional medicine, and in recent years it has been the object of increasing research interest. In combating liver diseases, it seems clear that curcumin exerts a hypolipidic effect, which prevents the fatty acid accumulation in the hepatocytes that may result from metabolic imbalances, and which may cause nonalcoholic steatohepatitis. Another crucial protective activity of curcumin, not only in the context of chronic liver diseases but also regarding carcinogenesis and other age-related processes, is its potent antioxidant activity, which affects multiple processes and signaling pathways. The effects of curcumin on NF-κβ are crucial to our understanding of the potent hepatoprotective role of this herb-derived micronutrient. Because curcumin is a micronutrient that is closely related to cellular redox balance, its properties and activity give rise to a series of molecular reactions that in every case and biological situation affect the mitochondria.