In the present study we developed a model of diet-induced obesity (DIO) in male C57 BL/6J mice using an 8-wk high fat diet. This model should better reflect the physiology of the majority of the human obese patients than mouse genetic models of obesity with defects in leptin or leptin signaling. At the end of the diet, DIO mice displayed an increased weight (20%) and higher leptin, insulin, glucose, and corticosterone plasma levels compared with mice fed a standard diet during the same period. Moreover, they became resistant to the central effect of peripheral administration of leptin. Oligonucleotide microarray studies were conducted in adipose tissue. They showed that a great number of genes are differentially expressed. The majority of these genes (69%) are down-regulated in DIO mice. Among those are genes encoding enzymes of the lipid metabolism or markers of adipocyte differentiation, enzymes involved in detoxification processes, as well as structural components of the cytoskeleton. Some other groups of genes displayed increased expression, such as those encoding inflammatory markers. The results of the microarray analysis were confirmed by semiquantitative RT-PCR studies run on a selected number of genes that were differentially expressed or not modified.

Colorectal cancer (CRC) is one of the leading causes of cancer deaths in Western countries. A significant number of CRC patients undergoing curatively intended surgery subsequently develop recurrence and die from the disease. MicroRNAs (miRNAs) are aberrantly expressed in cancers and appear to have both diagnostic and prognostic significance. In this study, we identified novel miRNAs associated with recurrence of CRC, and their possible mechanism of action. TaqMan V R Human Micro-RNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosas and 46 microsatellite stable CRC tumors. Four miRNAs (miR-362-3p, miR-570, miR-148 a* and miR-944) were expressed at a higher level in tumors from patients with no recurrence (p<0.015), compared with tumors from patients with recurrence. A significant association with increased disease free survival was confirmed for miR-362-3p in a second independent cohort of 43 CRC patients, using single TaqMan V R microRNA assays. In vitro functional analysis showed that over-expression of miR-362-3p in colon cancer cell lines reduced cell viability, and proliferation mainly due to cell cycle arrest. E2F1, USF2 and PTPN1 were identified as potential miR-362-3p targets by mRNA profiling of HCT116 cells over-expressing miR-362-3p. Subsequently, these genes were confirmed as direct targets by Luciferase reporter assays and their knockdown in vitro phenocopied the effects of miR-362-3p over-expression. We conclude that miR-362-3p may be a novel prognostic marker in CRC, and hypothesize that the positive effects of augmented miR-362-3p expression may in part be mediated through the targets E2F1, USF2 and PTPN1.

Circulating tumor (ctDNA) can be used for sensitive detection of minimal residual disease (MRD). However, the probability of detecting ctDNA at low tumor burden is limited by the number of mutations analyzed and available plasma volume. Here we applied a tumor-informed WGS approach for ctDNA-based MRD detection (91% sensitivity, 92% specificity) and treatment response evaluation in 916 longitudinally collected plasma samples from 112 patients with localized muscle-invasive bladder cancer. We show that WGS-based ctDNA detection is prognostic of patient outcomes with a median lead time of 131 days over radiographic imaging. We performed genomic characterization of post-treatment plasma samples to study tumor evolution and observed acquisition of the platinum therapy-associated mutational signatures and copy number variations not present in the primary tumors. Our results support the use of WGS for ultra-sensitive ctDNA detection, and highlight how tracking of tumor evolution using WGS of plasma samples opens opportunities to refine precision oncology.

In a previous study KIAA1199 was found to be upregulated in colon adenomas. A depletion of beta-catenin resulted in silencing of KIAA1199, suggesting a potential role in wnt/beta signaling. Aim of this study was to correlate KIAA1199 expression with patient outcome, to identify KIAA1199 downstream target genes and to elucidate its function and pathway association. Here we show by transcript profiling of &gt;400 colon adenocarcinomas that KIAA1199 is strongly increased in &gt;75% of colon adenocarcinomas compared to normal mucosas. Immunohistochemical analyses with a monospecific antibody identified the protein to be expressed in the nucleus and the cytoplasm of adenocarcinomas, and a strong upregulation of the KIAA1199 protein compared to normal, as also seen in several other types of cancer. Cloning identified a splice isoform lacking exon 28 resulting in a truncated KIAA1199 protein. Microarray profiling of SW480 cells transiently overexpressing, or stably depleted from, KIAA1199 identified genes involved in cell cycle regulation, cell signaling, cellular movement and cell to cell interaction. In vitro functional analyses indicated that cells depleted from KIAA1199 showed reduced cellular adhesion, a decreased proliferation rate and migrated less than control cells. KIAA1199 silencing affected the expression of eighteen genes, known to be involved in the wnt/beta catenin signaling pathway. The identified target genes correlated with KIAA1199 expression in normal colon mucosa and adenocarcinomas of stage II and III (Pearson 0.7-0.9). In conclusion, our data provide evidence that KIAA1199 is a regulatory part of the wnt/beta catenin signaling, sited downstream of beta-catenin and upstream of the stem cell marker ASCL2. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4678.

Colorectal cancer (CRC) is one of the leading causes of cancer death in Western countries. A significant number of CRC patients undergoing curative-intented surgery subsequently develop recurrence and die from the disease. MicroRNAs (miRNAs) are aberrantly expressed in cancers and appear to have both diagnostic and prognostic significance. In this study we identified novel miRNAs associated with recurrence of CRC. TaqMan® Human MicroRNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosas and 46 microsatellite stable CRC tumors. Four miRNAs (miR-362-3p, miR-570, miR-148a* and miR-944) were expressed at a lower level in the tumors from patients with recurrence (p &lt; 0.015) compared to tumors from patients with no recurrence. A significant association of low expression with reduced disease free survival was confirmed for miR-362-3p in a second independent cohort of 43 CRC patients using single TaqMan® microRNA assays. In vitro functional analysis showed that over-expression of miR-362-3p in colon cancer cell lines (HCT116, LS174T, and DLD1) reduced cell viability and proliferation mainly due to cell cycle arrest. E2F1, USF2 and PTPN1 were identified as potential miR-362-3p targets by mRNA profiling of HCT116 cells over-expressing miR-362-3p. Subsequently, these genes were confirmed as direct targets by Luciferase reporter assays. In vitro knock-down confirmed that these targets are important players in the miR-362-3p target network. We conclude that miR-362-3p may be a novel prognostic marker in CRC and hypothesize that augmented expression of miR-362-3p may prevent the development of distant metastasis by targeting E2F1, USF2 and PTPN1. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4138. doi:1538-7445.AM2012-4138