Protection of hepatocytes from apoptosis by a novel substance from actinomycetes culture medium

Immunization with UV-Induced Apoptotic Cells Generates Monoclonal Antibodies Against Proteins Differentially Expressed in Hepatocellular Carcinoma Cell Lines

Early and differential diagnosis of hepatocellular carcinoma (HCC) requires sensitive and specific tissue and serum markers. On the other hand, proteins involved in tumorigenesis are extensively modulated on exposure to apoptotic stimuli, including ultraviolet (UVC) irradiation. Hence, we generated monoclonal antibodies by using UVC-irradiated apoptotic cells of an HCC cell line, HUH7, aiming to explore proteins differentially expressed in tumors and apoptosis. We obtained 18 hybridoma clones recognizing protein targets in apoptotic HUH7 cells, and clone 6D5 was chosen for characterization studies because of its strong reactivity in cell-ELISA assay. Subtype of the antibody was IgG3 (kappa). Targets of 6D5 antibody were found to be abundantly expressed in all HCC cell lines except FLC4, which resembles normal hepatocytes. We also observed the secretion of 6D5 ligands by some of the HCC cell lines. Moreover, cellular proteins recognized by the antibody displayed a late upregulation in UVC-induced apoptotic cells. We concluded that 6D5 target proteins are modulated in liver tumorigenesis and apoptotic processes. We therefore propose the validation of our antibody in tissue and serum samples of HCC patients to assess its potential use for the early diagnosis of HCC and to understand the role of 6D5 ligands in liver carcinogenesis.

Neuroglobin and cytoglobin expression in mice

Although essentially unknown, several functions are hypothesized for neuroglobin and cytoglobin, two new members of the globin family. In this article, we try to shed more light on their possible roles in hypoxia and detoxification of reactive oxygen species in vivo. The relative transcriptional changes of neuroglobin and cytoglobin in a situation of chronic hypoxia in mice were examined using real-time quantitative PCR. The kinetics of the hypoxic expression of neuroglobin (brain, eyes) and cytoglobin (brain, eyes, liver, heart, skeletal muscle) is organ-specific. Moreover, reactive oxygen species production is higher in liver than in the other tissues. In eyes, the negative correlation, after reoxygenation, between neuroglobin protein level and H(2)O(2) concentration is a first proof of a reactive oxygen species-scavenging function for neuroglobin. In addition, apoptotic cell death after hypoxia is for the first time demonstrated in heart and liver.