Investigation of the putative role of antisense transcripts as regulators of sense transcripts by correlation analysis of sense-antisense pairs in colorectal cancers.

Antisense transcription occurs widely more expected than when it was first identified in bacteria in the 1980s. However, the functional relevance of antisense transcripts in transcription remains controversial. Here, we investigated the putative role of antisense transcripts in regulating their corresponding sense transcripts by analyzing changes in correlative relationships between sense-antisense pairs under tumor and normal conditions. A total of 3469 sense-antisense gene pairs (SAGPs) downloaded from BioMart mapped to a list of sense and antisense genes in RNA-seq data derived from 80 paired colorectal cancer (CRC) samples were analyzed. As a result, cancer-related genes were significantly enriched in the significantly correlated SAGPs (SCPs). Differentially expressed genes estimated between normal and tumor conditions were also significantly more enriched in SCPs than in non-SCPs. Interestingly, using differential correlation analysis, we found that tumor samples had a significantly larger density of genes with higher correlation coefficients than normal samples, as verified by various cancer transcriptomes from The Cancer Genome Atlas (TCGA). Moreover, we found that the magnitude of the correlation between SAGPs could distinguish poor prognostic CRCs from good prognostic CRCs, showing that correlation coefficients between the SAGPs of CRCs with a poor prognosis were significantly stronger than CRCs with a good prognosis. Consistent with this finding, the Cox proportion hazards model showed that the survival rates were significantly different between patients with high and low expression of genes in the SCPs. All these results strongly support the idea that antisense transcripts are important regulators of their corresponding sense transcripts.

Putative positive role of inflammatory genes in fat deposition supported by altered gene expression in purified human adipocytes and preadipocytes from lean and obese adipose tissues.

BACKGROUND: Obesity is a chronic low-grade inflammatory disease that is generally characterized by enhanced inflammation in obese adipose tissue (AT). Here, we investigated alterations in gene expression between lean and obese conditions using mRNA-Seq data derived from human purified adipocytes (ACs) and preadipocytes (preACs). RESULTS: Total mRNA-seq data were generated with 27 AC and 21 preAC samples purified from human visceral AT collected during resection surgery in cancer patients, where the samples were classified into lean and obese categories by BMI > 25 kg/m2. We defined four classes of differentially expressed genes (DEGs) by comparing gene expression between (1) lean and obese ACs, (2) lean and obese preACs, (3) lean ACs and lean preACs, and 4) obese ACs and obese preACs. Based on an analysis of comparison 1, numerous canonical obesity-related genes, particularly inflammatory genes including IL-6, TNF-α and IL-1ß, i.e., the genes that are expected to be upregulated in obesity conditions, were found to be expressed at significantly lower levels in obese ACs than in lean ACs. In contrast, some inflammatory genes were found to be expressed at higher levels in obese preACs than lean preACs in the analysis of comparison 2. The analysis of comparisons 3 and 4 showed that inflammatory gene classes were expressed at higher levels in differentiated ACs than undifferentiated preACs under both lean and obese conditions; however, the degree of upregulation was significantly greater for lean than for obese conditions. We validated our observations using previously published microarray transcriptome data deposited in the GEO database (GSE80654). CONCLUSIONS: Taken together, our analyses suggest that inflammatory genes are expressed at lower levels in obese ACs than in lean ACs because lean adipogenesis involves even greater enhancement of inflammatory responses than does obese adipogenesis.

Smoking-Related DNA Methylation is Differentially Associated with Cadmium Concentration in Blood.

Tobacco smoking, a risk factor for several human diseases, can lead to alterations in DNA methylation. Smoking is a key source of cadmium exposure; however, there are limited studies examining DNA methylation alterations following smoking-related cadmium exposure. To identify such cadmium exposure-related DNA methylation, we performed genome-wide DNA methylation profiling using DNA samples from 50 smokers and 50 non-smokers. We found that a total of 136 CpG sites (including 70 unique genes) were significantly differentially methylated in smokers as compared to that in non-smokers. The CpG site cg05575921 in the AHRR gene was hypomethylated (Δ ß > - 0.2) in smokers, which was in accordance with previous studies. The rs951295 (within RNA gene LOC105370802) and cg00587941 sites were under-methylated by > 15% in smokers, whereas cg11314779 (within CELF6) and cg02126896 were over-methylated by ≥ 15%. We analyzed the association between blood cadmium concentration and DNA methylation level for 50 smokers and 50 non-smokers. DNA methylation rates of 307 CpG sites (including 207 unique genes) were significantly correlated to blood cadmium concentration (linear regression P value < 0.001). The four significant loci (cg05575921 and cg23576855 in AHRR, cg03636183 in F2RL3, and cg21566642) were under-methylated by > 10% in smokers compared to that in non-smokers. In conclusion, our study demonstrated that DNA methylation levels of rs951295, cg00587941, cg11314779, and cg02126896 sites may be new putative indicators of smoking status. Furthermore, we showed that these four loci may be differentially methylated by cadmium exposure due to smoking.

Degeneration of acetabular articular cartilage to bipolar hemiarthroplasty.

PURPOSE: This study examined the rate of degeneration of acetabular cartilage by the bipolar head according to time, and also which clinical factors are related to the degeneration of acetabular cartilage. MATERIALS AND METHODS: Among 192 patients (226 hip joints) who received bipolar hemiarthroplasty from August 1996 to August 2002, 61 patients (65 hip joints) were enrolled in this study, who were followed up for more than 2 years and showed no signs of dislocation, infection, or functional problems. A modified form of a computer assisted vector wear analysis program was used to measure the rate of degeneration of the acetabular cartilage. The factors that appeared to affect the rate of acetabular degeneration in the two groups was evaluated. RESULTS: The average linear degenerative change in the acetabular cartilage and the volumetric degenerative change were 0.23 +/- 0.107mm/year and 114 +/- 47.2mm3/year, respectively. The result showed significant differences in activity and HHS between the 2 groups. The HHS showed a reverse relationship with the linear degeneration and volumetric degeneration, and the activity showed a correlation with the linear and volumetric degeneration. CONCLUSION: The acetabular cartilage degenerates faster as the patient' activity increases, and slower with a higher HHS. When surgeons perform hip joint arthroplasty, it is strongly recommended that the life expectancy and the level of activity should be considered when deciding between a hemiarthroplasty and total hip arthroplasty.