The beneficial health properties of the Mediter-ranean diet are well recognized. The principle source of fat in Mediterranean diet is extra-virgin olive oil (EVOO). Oleocanthal (OC) is a naturally occurring minor phenolic compound isolated from EVOO, which has shown a potent anti-inflammatory activity, by means of its ability to inhibit the cyclooxygenase (COX) enzymes COX-1 and COX-2. A large body of evidence indicates that phenols exhibit anticancer activities. The aim of the present study was to evaluate the potential anticancer effects of OC in hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC) models. A panel of human HCC (HepG2, Huh7, Hep3B and PLC/PRF/5) and CRC (HT29, SW480) cell lines was used. Cells were treated with OC, and cell viability and apoptosis were evaluated. Compared with classical commercially available COX inhibitors (ibuprofen, indomethacin, nimesulide), OC was more effective in inducing cell growth inhibition in HCC and CRC cells. Moreover, OC inhibited colony formation and induced apoptosis, as confirmed by PARP cleavage, activation of caspases 3/7 and chromatin condensation. OC treatment in a dose dependent-manner induced expression of γH2AX, a marker of DNA damage, increased intracellular ROS production and caused mitochondrial depolarization. Moreover, the effects of OC were suppressed by the ROS scavenger N-acetyl-L-cysteine. Finally, OC was not toxic in primary normal human hepatocytes. In conclusion, OC treatment was found to exert a potent anticancer activity against HCC and CRC cells. Taken together, our findings provide preclinical support of the chemotherapeutic potential of EVOO against cancer.

Interleukin-6 (IL-6) is a pleiotropic cytokine which is expressed in many inflammatory cells in response to different types of stimuli, regulating a number of biological processes. The IL-6 gene is polymorphic in both the 5' and 3' flanking regions and more than 150 single nucleotide polymorphisms have been identified so far. Genetic polymorphisms of IL-6 may affect the outcomes of several diseases, where the presence of high levels of circulating IL-6 have been correlated to the stage and/or the progression of the disease itself. The -174 G/C polymorphism is a frequent polymorphism, that is located in the upstream regulatory region of the IL-6 gene and affects IL-6 production. However, the data in the literature on the genetic association between the -174 G/C polymorphism and some specific liver diseases characterized by different etiologies are still controversial. In particular, most of the studies are quite unanimous in describing a correlation between the presence of the high-producer genotype and a worse evolution of the chronic liver disease. This is valid for patients with hepatitis C virus (HCV)-related chronic hepatitis and liver cirrhosis and hepatocellular carcinoma (HCC) whatever the etiology. Studies in hepatitis B virus-related chronic liver diseases are not conclusive, while specific populations like non alcoholic fatty liver disease/non-alcoholic steatohepatitis, autoimmune and human immunodeficiency virus/HCV co-infected patients show a higher prevalence of the low-producer genotype, probably due to the complexity of these clinical pictures. In this direction, a systematic revision of these data should shed more light on the role of this polymorphism in chronic liver diseases and HCC.

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