Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells

Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.Instituto de Salud Carlos III PI13/00021Ministerio de Economía y Competitividad BFU2012-32056Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía BIO-0216Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía CTS-6264Consejería de Salud, Junta de Andalucía PI13/ 0002

Nitric Oxide Synthase Type III Overexpression By Gene Therapy Exerts Antitumoral Activity In Mouse Hepatocellular Carcinoma

Hepatocellular carcinoma develops in cirrhotic liver. The nitric oxide (NO) synthase type III (NOS-3) overexpression induces cell death in hepatoma cells. The study developed gene therapy designed to specifically overexpress NOS-3 in cultured hepatoma cells, and in tumors derived from orthotopically implanted tumor cells in fibrotic livers. Liver fibrosis was induced by CCl4 administration in mice. Hepa 1-6 cells were used for in vitro and in vivo experiments. The first generation adenovirus was designed to overexpress NOS-3 (or GFP) and luciferase cDNA under the regulation of murine alpha-fetoprotein (AFP) and Rous Sarcoma Virus (RSV) promoters, respectively. Both adenoviruses were administered through the tail vein two weeks after orthotopic tumor cell implantation. AFP-NOS-3/RSV-Luciferase increased oxidative-related DNA damage, p53, CD95/CD95L expression and caspase-8 activity in cultured Hepa 1-6 cells. The increased expression of CD95/CD95L and caspase-8 activity was abolished by l-NAME or p53 siRNA. The tail vein infusion of AFP-NOS- 3/RSV-Luciferase adenovirus increased cell death markers, and reduced cell proliferation of established tumors in fibrotic livers. The increase of oxidative/nitrosative stress induced by NOS-3 overexpression induced DNA damage, p53, CD95/CD95L expression and cell death in hepatocellular carcinoma cells. The effectiveness of the gene therapy has been demonstrated in vitro and in vivo

Incidence and survival rate of de novo tumors in liver transplants

The greater survival of transplanted patients is accompanied by an increase in the rate of de novo malignancies (NM), which are the most frequent late-onset complication. We can distinguish between non-melanoma skin cancers (NMSC), post-transplant lymphoproliferative disorders (PTLD) and solid organ cancers (SOC). Our objective is to determine the incidence of the different types of NM, the time elapsed until diagnosis and survival rates in our setting. We conducted a retrospective study of 1071 liver transplant patients from 1990 to 2015 at our center. We analyzed the demographic variables, incidence of NM and survival. 184 NM developed in 1071 transplant patients (17%), specifically 19% of the males and 13% of the females (P=.004). The most frequent NM were NMSC (29%), lung (18%), head and neck (16%), PTLD (10%) and gastrointestinal (8%). The median time of diagnosis was 7.9 years in NMSC, 3.9 years in PTLD and 9.8 years in SOC. Patients with NMSC had significantly better survival than those with PTLD or SOC. The incidence of de novo tumors (excluding NMSC) was 1889/100,000 transplants/year. By gender, lung cancer was the most common TOS in men and breast cancer in women. In our setting, excluding NMSC, the incidence is 8.8 times greater than estimations for the general population, with a high rate of lung cancer, so we should implement preventive and diagnostic strategies