Project description:Recent studies have shown that circular RNAs (circRNAs) are abundant, widely expressed in mammals, and can display cell-type specific expression. However, how production of circRNAs is regulated and their precise biological function remains largely unknown. To study how circRNAs might be regulated during colorectal cancer progression, we used three isogenic colon cancer cell lines that differ only in KRAS mutation status. Cellular RNAs from the parental DLD-1 cells that contain both wild-type and G13D mutant KRAS alleles and isogenically-matched derivative cell lines, DKO-1 (mutant KRAS allele only) and DKs-8 (wild-type KRAS allele only) were analyzed using RNA-Seq. We developed a bioinformatics pipeline to identify and evaluate circRNA candidates from RNA-Seq data. Hundreds of high-quality circRNA candidates were identified in each cell line. Remarkably, circRNAs were significantly down-regulated at a global level in DLD-1 and DKO-1 cells compared to DKs-8 cells, indicating a widespread effect of mutant KRAS on circRNA abundance. This finding was confirmed in two independent colon cancer cell lines HCT116 (KRAS mutant) and HKe3 (KRAS WT). In all three cell lines, circRNAs were also found in secreted extracellular-vesicles, and circRNAs were more abundant in exosomes than cells. Our results suggest that circRNAs may serve as promising cancer biomarkers.
Project description:Gene expression profile of two reporgrammed cell lines iPSC CRL1831 (induced pluripotent stem cells) and CSC DLD1 (cancer stem-like cells) derived from normal colon CRL1831 and colorectal cancer DLD-1 cells, after transfer to 3D cell culture conditions and cell lines treated with single or fractionated ionizing radiation doses under 3D cell culture conditions. There are no data that cancer metastases arise due to specific mutations of cancer cells. Therefore ongoing investigation of reprogrammed cancer cells grown in three-dimensional (3D) cell culture models might provide researchers with essential data studying tumor oncogenesis and metastases formation. 3D culture models were shown to mimic in vivo cell microenvironment more accurately than the standard two-dimensional cell monolayer (2D) cultures. Also, growing evidence suggests that 2D and 3D cultured cells gene expression pattern variance following irradiation is highly dependent on cancer cell state and their interaction with microenvironment.
Project description:Fibroblasts isolated from human colon submucosal and subperitoneal layer were stimulated by colon cancer cell line (DLD-1) cultured medium. Peritoneal invasion in colon cancer is an important prognostic factor, and the fibrosis with α-SMA was a significant pathological feature of the cancer microenvironment formed by peritoneal invasion (CMPI). The result indicated that the gene expression of subperitoneal fibroblasts showed more various gene modification than submucosal fibroblasts. And ACTA2 expression was higher in fibroblasts from subperitoneal layer than that from submucosal layer. Together with this concordant stromal protein expression in CMPI, this in vitro model is able to reflect the special microenvironment in CMPI. 3 cases of human colon submucosal and subperitoneal fibroblasts were isolated, and these fibroblasts were stimulated with DLD-1 cultured medium. Total RNA were extracted from these samples and hybridized in Affymetrix microarray to compare their gene expression changes through the DLD-1 stimulation
Project description:Using human colon cancer DLD-1 cells, we engineered a cell line with a doxycycline-inducible single-copy of Snail and compared it to an existing EMT models in DLD-1 where Snail was introduced by episome transfection. Induction of the single-copy line (Snail-lo) with doxycycline increased Snail expression to a level similar to that observed in cancer cell lines spontaneously expressing Snail and results in partial EMT. In comparison, higher levels of overexpression arising from introduction of episomal-Snail (Snail-hi), results in complete EMT.
Project description:MicroRNAs (miRNAs) have emerged as important gene regulators and are recognized as key players in tumorigenesis. miR-143 is reported to be down-regulated in several cancers, but knowledge of its targets in colon cancer remains limited. To investigate the role of miR-143 in colon cancer, we have employed a microarray based approach to identify miR-143 targets. Based on seed site enrichment analyses and unbiased word analyses, we found a significant enrichment of miRNA binding sites in the 3M-bM-^@M-^Y-untranslated regions (UTRs) of transcripts down-regulated upon miRNA overexpression. Here we identify Hexokinase 2 (HK2) as a direct target of miR-143 and show that re-introduction of miR-143 in the colon cancer cell line DLD-1 results in a decreased lactate secretion, indicating that miR-143 down-regulation of HK2 affects glucose metabolism in colon cancer cells. DLD-1 cells were transfected with 50 nM miR-143 duplex or mock transfected. Total RNA was harvested 24 hours post-transfection and analyzed on Affymetrix HG-U133 Plus 2.0 human arrays.
Project description:Despite the efforts in defining the molecular mechanisms for the drug resistance in colorectal cancers, little is known about the roles of microRNAs. With microarray containing 723 microRNAs, we examined effect of 5-fluorouracil (5-FU) on the microRNA expression. Respond to 5-FU, we identify two microRNAs, miR-19b and miR-21, that were differentially expressed in 5-FU resistant colon cancer cells derived from KM12C and DLD-1. DLD-1, DLD-1/R, KM12C, and KM12C/R cells were plated at 1 × 105 cells/well. After pre-culture, cells were treated with 60 uM of 5-FU for 72 h. This was the same condition as the analysis of cell cycle. RNAs were collected before (0 h) and after the treatment of 5-FU (72 h).