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Skeletal muscle may also contribute to the circulating plasma IL-6 and increased oxidative stress during HD.

BackgroundEpidermal growth factor (EGF) and its receptor (EGFR) constitute a principal growth-promoting pathway in endometrial cancer cells. Pre-clinical studies were undertaken to compare the expression of EGFR isoforms and the downstream effects of activating or blocking EGFR function in Ishikawa H cells, derived from a moderately differentiated type I endometrioid adenocarcinoma, or in Hec50co cells, derived from a poorly differentiated type II adenocarcinoma with papillary serous sub-differentiation.ResultsWe investigated whether EGFR mutations are present in the tyrosine kinase domain (exons 18-22) of EGFR and also whether EGFR isoforms are expressed in the Ishikawa H or Hec50co cell lines. Sequence of the EGFR tyrosine kinase domain proved to be wild type in both cell lines. While both cell lines expressed full-length EGFR (isoform A), EGFR and sEGFR (isoform D) were expressed at significantly lower levels in Hec50co cells compared to Ishikawa H cells. Analysis of gene expression following EGF vs. gefitinib treatment (a small molecule EGFR tyrosine kinase inhibitor) was performed. Early growth response 1, sphingosine kinase 2, dual specificity phosphatase 6, and glucocorticoid receptor DNA binding factor 1 are members of a cluster of genes downstream of EGFR that are differentially regulated by treatment with EGF compared to gefitinib in Ishikawa H cells, but not in Hec50co cells.ConclusionsType I Ishikawa H and type II Hec50co endometrial carcinoma cells both express EGFR and sEGFR, but differ markedly in their responsiveness to the EGFR inhibitor gefitinib. This difference is paralleled by differences in the expression of sEGFR and EGFR, as well as in their transcriptional response following treatment with either EGF or gefitinib. The small cluster of differently regulated genes reported here in these type I vs. type II endometrial cancer-derived cell lines may identify candidate biomarkers useful for predicting sensitivity to EGFR blockade.

Purpose Accumulation of mitochondrial DNA (mtDNA) deletions and the resultant impaired oxidative phosphorylation may play a pathogenic role in the mediation of age-related sarcopenia. Methods Twenty four participants of the New Mexico Aging Process Study were classified as normal lean (n=15) or sarcopenic (n=9) based on body composition determined by Dual Energy X-ray Absorptiometry. Complex I and IV activities were measured in the skeletal muscle samples obtained from gastrocnemius muscle. A two-stage nested PCR strategy was used to identify the mtDNA deletions in the entire mitochondrial genome in the skeletal muscle samples. Results While complex I activity was not significantly different (5.5 ± 0.9 vs. 4.6 ± 0.7 mU/mg protein, p>0.05), complex IV activity was higher in sarcopenic subjects (1.4 ± 0.3 vs. 1.0 ± 0.1 mU/mg protein, p<0.05). mtDNA deletions were mostly located in the region of complex I and spanned from NADH dehydrogenase (ND)1 to ND6. Deletions in the 8577–10407 bp and 10233–11249 bp regions were associated with a significant decrease in complex I activity (p<0.05 and p=0.02 respectively). Total cumulative deletion, defined as the sum of individual length of deletions in a subject, was comparable in subjects with and without sarcopenia (1760 ± 726 vs. 1782 ± 888 bp, p>0.05). The magnitude of mtDNA deletion, however, correlated positively with lean body mass (r=0.43, p<0.05). Conclusion Thus, mtDNA deletions are common in elderly subjects and are negatively related to complex I activity. The positive association between mtDNA deletions and lean body mass needs to be confirmed by studies in a larger study population.