Screening for genetic abnormalities involved in ovarian carcinogenesis using retroviral expression libraries
INTERNATIONAL JOURNAL OF ONCOLOGY
Authors: Wada, Tomoaki; Yamashita, Yoshihiro; Saga, Yasushi; Takahashi, Kayoko; Koinuma, Koji; Choi, Young Lim; Kaneda, Ruri; Fujiwara, Shin-Ichiro; Soda, Manabu; Watanabe, Hideki; Kurashina, Kentaro; Hatanaka, Hisashi; Enomato, Munehiro; Takada, Shuji; Mano, Hiroyuki; Suzuki, Mitsuaki
Abstract
The purpose of this study was to screen for genes involved in ovarian carcinogenesis in an attempt to develop an effective molecular-targeted therapy for ovarian cancer. We constructed retroviral expression libraries for the human ovarian cancer cell lines SHIN-3 and TYK-CPr, and performed a focus formation assay with 3T3 cells. As a result, proteasome subunit beta-type 2 (PSMB2), ubiquitin-specific protease 14 (USP14), and keratin 8 (KRT8) were identified from SHIN-3, and polymerase H RNA subunit (POLR2E), chaperonin containing T-complex polypeptide 1 subunit 4 (CCT4), glia maturation factor beta (GMFB), and neuroblastoma ras viral oncogene homolog (NRAS) from TYK-CPr. NRAS gene analysis revealed a CAA -> AAA substitution at codon 61, resulting in a Glu -> Lys change at position 61. When the mutant NRAS was introduced into fibroblasts for its expression, many transformed foci were generated, confirming the transforming ability of the mutant NRAS.
Non-Coding Keratin Variants Associate with Liver Fibrosis Progression in Patients with Hemochromatosis
PLOS ONE
Authors: Strnad, Pavel; Kucukoglu, Ozlem; Lunova, Mariia; Guldiken, Nurdan; Lienau, Tim C.; Stickel, Felix; Omary, M. Bishr
Abstract
Background: Keratins 8 and 18 (K8/K18) are intermediate filament proteins that protect the liver from various forms of injury. Exonic K8/K18 variants associate with adverse outcome in acute liver failure and with liver fibrosis progression in patients with chronic hepatitis C infection or primary biliary cirrhosis. Given the association of K8/K18 variants with end-stage liver disease and progression in several chronic liver disorders, we studied the importance of keratin variants in patients with hemochromatosis. Methods: The entire K8/K18 exonic regions were analyzed in 162 hemochromatosis patients carrying homozygous C282Y HFE (hemochromatosis gene) mutations. 234 liver-healthy subjects were used as controls. Exonic regions were PCR-amplified and analyzed using denaturing high-performance liquid chromatography and DNA sequencing. Previously-generated transgenic mice overexpressing K8 G62C were studied for their susceptibility to iron overload. Susceptibility to iron toxicity of primary hepatocytes that express K8 wild-type and G62C was also assessed. Results: We identified amino-acid-altering keratin heterozygous variants in 10 of 162 hemochromatosis patients (6.2%) and non-coding heterozygous variants in 6 additional patients (3.7%). Two novel K8 variants (Q169E/R275W) were found. K8 R341H was the most common amino-acid altering variant (4 patients), and exclusively associated with an intronic KRT8 IVS7+ 10delC deletion. Intronic, but not amino-acid-altering variants associated with the development of liver fibrosis. In mice, or ex vivo, the K8 G62C variant did not affect iron-accumulation in response to iron-rich diet or the extent of iron-induced hepatocellular injury. Conclusion: In patients with hemochromatosis, intronic but not exonic K8/K18 variants associate with liver fibrosis development.