Project description:Circular RNAs (circRNAs) represent critical roles in the biology of various cancers. However, their expression patterns and biological functions in human colorectal cancer (CRC) remain largely unknown. The aim of this study was to explore circRNAs profiles in CRC and investigate key circRNAs involved in CRC tumourigenesis and progression.
Project description:Long noncoding RNAs (lncRNAs) have been shown to play critical roles in the biology of various cancers. However, their expression patterns and biological functions in human colorectal cancer (CRC) remain largely unknown. The aim of this study was to explore lncRNA profiles in CRC and investigate key lncRNAs involved in CRC tumourigenesis and progression.
Project description:K-ras mutations are observed in around 40% human colorectal adenomas and carcinomas and contribute to the pathogenesis of human and rodent colorectal tumour formation. Previously, we developed and characterised a strain of transgenic mice with inducible intestinal epithelial expression of K-rasVal12 via a Cre/LoxP system. To evaluate the influence of mutant K-ras on carcinogen-induced colorectal tumourigenesis, we induced neoplastic alterations in the large intestines of wild-type and K-rasVal12 mice using the colon-selective carcinogen 1, 2-dimethylhydrazine (DMH), which has been widely used to study chemically induced colorectal tumours that are histopathologically similar to those observed in humans. K-rasVal12 expression significantly promoted DMH-induced colorectal tumourigenesis: the average life span of the mice decreased from 38.52±1.97 weeks for 40 wild-type mice to 32.42±2.17 weeks for 26 K-rasVal12 mice (mean+SEM, P<0.05) and the large intestinal tumours increased from 2.27±0.15 per wild-type mouse to 3.85±0.20 in K-rasVal12 mice (mean+SEM, P<0.01). Adenomas from DMH-treated K-rasVal12 mice showed significantly higher levels (10.9±1.69%) of Ki-67-positive proliferating cells compared with those from DMH-treated wild-type mice (7.77±1.15%) (mean+SD, P<0.01) and a mild increase in apoptotic nuclei staining for cleaved caspase-3 (1.94+0.51% compared with 1.15±0.34%, mean+SD, P<0.01). In the adenomas from DMH-treated K-rasVal12 mice, K-rasVal12 transgene recombination and expression were confirmed and shown to promote strong Erk and mild Akt activation compared with adenomas from DMH-treated wild-type mice. Microarray hybridization and cluster analysis demonstrated different expression profiles in adenomas from DMH-treated wild-type and DMH-treated K-rasVal12 mice, indicating involvement of different molecular mechanisms, but array-comparative genomic hybridisation analysis showed chromosome stability in both, with very few chromosome alterations observed in adenomas from either of the two groups. Taken together, these data show that mutant K-ras promotes DMH-induced colorectal tumourigenesis, conferring a proliferative effect, but does not alter chromosome stability in the tumours. This study has 7 samples analysed, 4 Kras mutants and 3 controls, on the Illumina Mouse-6 Beadchip array.
Project description:The endpoint of this study was to prospectively validate the prognostic significance of fecal Akk in advanced NSCLC patients treated with first or second line ICI. We performed RNA sequencing to compare transcriptomic profiles of the different groups.
Project description:The aberrant gain of DNA methylation at CpG islands (CGIs) is frequently observed in colorectal tumours and may silence the expression of tumour suppressors such as MLH1. Current models propose that these CGIs are targeted by de novo DNA methyltransferases (DNMTs) in a sequence-specific manner but this has not been tested. Using ectopically integrated CGIs, we find that aberrantly methylated CGIs are subject to low levels of de novo DNMT activity in colorectal cancer cells. By delineating DNMT targets, we find that instead de novo DNMT activity is targeted primarily to CGIs marked by the histone modification H3K36me3, a mark associated with transcriptional elongation. These H3K36me3 marked CGIs are heavily methylated in colorectal tumours and the normal colon suggesting that de novo DNMT activity at CGIs in colorectal cancer is focused on similar targets to normal tissues and not greatly remodelled by tumourigenesis.
Project description:The aberrant gain of DNA methylation at CpG islands (CGIs) is frequently observed in colorectal tumours and may silence the expression of tumour suppressors such as MLH1. Current models propose that these CGIs are targeted by de novo DNA methyltransferases (DNMTs) in a sequence-specific manner but this has not been tested. Using ectopically integrated CGIs, we find that aberrantly methylated CGIs are subject to low levels of de novo DNMT activity in colorectal cancer cells. By delineating DNMT targets, we find that instead de novo DNMT activity is targeted primarily to CGIs marked by the histone modification H3K36me3, a mark associated with transcriptional elongation. These H3K36me3 marked CGIs are heavily methylated in colorectal tumours and the normal colon suggesting that de novo DNMT activity at CGIs in colorectal cancer is focused on similar targets to normal tissues and not greatly remodelled by tumourigenesis.