Differential gene expression profiles of radioresistant oesophageal cancer cell lines established by continuous fractionated irradiation
BRITISH JOURNAL OF CANCER
Authors: Fukuda, K; Sakakura, C; Miyagawa, K; Kuriu, Y; Kin, S; Nakase, Y; Hagiwara, A; Mitsufuji, S; Okazaki, Y; Hayashizaki, Y; Yamagishi, H
Abstract
Radiation therapy is a powerful tool for the treatment of oesophageal cancer. We established radioresistant cell lines by applying fractionated irradiation in order to identify differentially expressed genes between parent and radioresistant cells. Six oesophageal cancer cell lines (TE-2, TE-5, TE-9, TE-13, KYSE170, and KYSE180) were treated with continuous 2 Gy fractionated irradiation (total dose 60 Gy). We compared expression profiles of each parent and radioresistant lines on a cDNA microarray consisting of 21168 genes. In the fractionated irradiation trial, four radioresistant sublines (TE-2R, TE-9R, TE-13R, KYSE170R) were established successfully, and we identified 19 upregulated and 28 downregulated genes common to radioresistant sublines. Upregulated genes were associated with apotosis and inflammatory response (BIRC2 and COX-2), DNA metabolism (CD73), and cell growth (PLAU). Downregulated genes were associated with apoptosis (CASP6), cell adhesion (CDH1 and CDH3), transcription (MLL3), and cell cycle (CDK6). Some of these genes were known to be associated with radiation response, such as COX-2, but others were novel. Reverse transcription-polymerase chain reaction confirmed that genes selected by cDNA microarray were overexpressed in clinical specimens of radioresistant cases. Global gene analysis of radioresistant sublines may provide new insight into mechanisms of radioresistance and effective radiation therapy.
Digenic inheritance of an autosomal recessive hypotrichosis in two consanguineous pedigrees
CLINICAL GENETICS
Authors: Basit, S.; Wali, A.; Aziz, A.; Muhammad, N.; Jelani, M.; Ahmad, W.
Abstract
Hypotrichosis is a human hereditary hair loss disorder in which affected individuals show sparse to complete absence of hair on scalp and/or on different body parts. To date, at least eight isolated autosomal recessive and dominant forms of hypotrichosis loci have been mapped on different human chromosomes, and the corresponding genes have been identified. Detailed clinical and molecular studies were undertaken of the hereditary hypotrichosis observed in the two consanguineous families (A and B) presented here. Human genome scan, using >500 highly polymorphic microsatellite markers, identified equal evidence of linkage of the hypotrichosis phenotype on chromosomes 12q21.2-q22 and 16q21-q23.1 in both the families. The novel hypotrichosis locus on chromosome 12q21.2-q22 spans 16.3 cM (17.62 Mb), flanked by markers D12S326 and D12S101. At this locus, maximum multipoint logarithm of the odds ratio (LOD) scores of 3.68 and 3.31 were obtained in families A and B, respectively. The second hypotrichosis locus on chromosome 16q21-q23.1, identified in the two families, spans 5.58 cM (8.28 Mb) and is flanked by markers D16S3031 and D16S512. Maximum multipoint LOD scores of 3.17 and 3.31 were obtained with markers mapped at this locus in families A and B, respectively. DNA sequence analysis of six candidate genes (PLEKHG7, SLC6A15, VEZT, DUSP6, KERA and KITLG), located in the linkage interval on chromosome 12q21.2-q22, failed to detect potential sequence variants in the affected individuals of the two families. However, DNA sequence analysis of CDH3 gene, located on chromosome 16q21-q23.1, detected a single base pair homozygous insertion (c.1024_1025insG and p.342insGfsX345) in exon 9 in family A and deletion of four base pair (c.1859_1862delCTCT and p.620delSfsX629) in exon 13 in family B. We described for the first time digenic inheritance of an autosomal recessive hypotrichosis phenotype in two unlinked loci on chromosomes 12q21.2-q22 and 16q21-q23.1 in two unrelated consanguineous Pakistani families.