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Hyperglycemia is a hallmark of diabetes, which is associated with protein glycation and misfolding, impaired cell metabolism and altered signaling pathways result in endoplasmic reticulum stress (ERS). We previously showed that L-lysine (Lys) inhibits the nonenzymatic glycation of proteins, and protects diabetic rats and type 2 diabetic patients against diabetic complications. Here, we studied some molecular aspects of the Lys protective role in high glucose (HG)-induced toxicity in C2C12 myotubes and 3T3-L1 adipocytes. C2C12 and 3T3-L1 cell lines were differentiated into myotubes and adipocytes, respectively. Then, they were incubated with normal or high glucose (HG) concentrations in the absence/presence of Lys (1 mM). To investigate the role of HG and/or Lys on cell apoptosis, oxidative status, unfolded protein response (UPR) and autophagy, we used the MTT assay and flow cytometry, spectrophotometry and fluorometry, RT-PCR and Western blotting, respectively. In both cell lines, HG significantly reduced cell viability and induced apoptosis, accompanying with the significant increase in reactive oxygen species (ROS) and nitric oxide (NO). Furthermore, the spliced form of X-box binding protein 1 (XBP1), at both mRNA and protein levels, the phosphorylated eukaryotic translation initiation factor 2α (p-eIf2α), and the Light chain 3 (LC3)II/LC3I ratio was also significantly increased. Lys alone had no significant effects on most of these parameters; but, treatment with HG plus Lys returned them all to, or close to, the normal values. The results indicated the protective role of Lys against glucotoxicity induced by HG in C2C12 myotubes and 3T3-L1 adipocytes.

As an experimental model, most studies rely on established human cancer cell lines; however, some genetical or phenotypical differences exist between these cells and their original tumor. Therefore, primary cells isolated directly from tissue are believed to be more biologically relevant tools for studying human and animal biology. Here, we aimed to isolate primary epithelial cancer and normal cells from breast tumors of Iranian women, for the first time. Thus, we isolated the epithelial and fibroblast cells from biopsy samples of patients with breast cancer based on differential centrifugation followed by culture in selective media. Normal epithelial cells obtained from the tissue biopsy away from the core of the tumor, based on the pathological diagnosis. Flow cytometry analysis indicated the positive immunoreactivity of the isolated epithelial cells against CD24 and Epithelial Specific Antigen (ESA/EpCAM), while they displayed a concomitant low expression of CD44 and CD49f. In contrat to fibroblasts, the qPCR data indicated the expression of luminal intracellular cytokeratin (Ck18) in both normal and cancer epithelial cells, but there was no expression of myoepithelial/basal markers, CK5 and vimentin. The epithelial cancer cells were reactive to cytokeratin 19 (CK19) antibody, whereas the normal epithelial cells were not. The expression of calmodulin-like protein (CLP) was also lower in the cancer epithelial cells than in the normal ones. In conclusion, primary epithelial normal and cancer cells, in addition to the fibroblasts were isolated and characterized from breast tumor of Iranian patients; and CLP expression is suggested as a susceptibility marker for breast cancer screening.

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