Abstract Recovery rates for baleen whales that were decimated by exploitation vary between species and populations. Age determination is critical for the understanding of recovery trends and population structure, but determining age in free‐ranging individuals remains challenging. Recent research has suggested that the methylation level of some genes in skin samples may provide age determinations with accuracy. We selected nine CpG sites from three genes ( TET2 , CDKN2A , and GRIA2 ) and analyzed them in 40 skin samples from known‐age individuals pertaining to two different populations of fin whales from the North Atlantic. We observed significant correlations with age in five CpG sites. We used three of these CpG sites to perform an epigenetic age estimation. Predictions had a standard deviation of 2.94, but regression between observed and predicted ages showed a clear underestimation for older fin whales. For further development, we suggest: (1) screening for new CpG sites associated with age that exhibit higher variability between individuals, and (2) including older animals whenever the sampling allows it. We also observed subtle, but significant differences between the two populations studied in one of the CpG sites (TET2_CpG + 21). We attributed these differences to genetic differences or to the dissimilar environments that affect both populations.

Biological and genetic cell heterogeneity is a landmark of most colorectal cancers and provides a frame for tumor progression as an evolutional process. Classical models have hypothesized that increased genetic instability may contribute to modulating and shaping malignant transformation. This is true for the small subset of colorectal cancers displaying microsatellite instability. For the rest of colorectal tumors, numerical and/or structural chromosomal alterations are the most prominent outcome of genetic disruption. These observations have prompted some investigators to hypothesize about the presence of chromosomal instability in these cells. To characterize chromosomal instability in cancer cells, we have analyzed genetic clonal divergence in three colorectal cancer cell lines considered to be archetypes in cancer research (HCT116, LoVo, and SW480). A dynamic setting was designed to allow the calculation of mutation rates. Comprehensive analyses at the chromosomal level revealed distinctive patterns of genetic divergence. Aneuploid SW480 cells displayed high rates of structural alterations (>100-fold) as compared with near diploid LoVo cells. Numerical alterations also occurred more frequently in SW480 cells but at low rates as compared with rearrangements in the chromosomically unstable SW480 cells. These results strengthen the role of structural instability in the generation of genetic heterogeneity in colorectal cancer.

Various studies have suggested the existence of different pathways of tumor progression in colorectal cancer that associate with specific molecular, chromosomal, and clinicopathological features. We hypothesize that a comprehensive analysis of cumulated genomic damage in colorectal cancers would aid the characterization of different tumor progression pathways and identify the factors determining clinical outcome of tumors of each type. Genome-wide disruption was studied by DNA fingerprinting in a series of 129 sporadic colorectal carcinomas. These results, taken together with data for DNA ploidy, microsatellite instability, p53, and K-ras mutations and clinicopathological characteristics of the patients, have been used to classify colorectal carcinomas. The following five groups can be defined based on the type and level of cumulated genomic damage: (a) tumors with microsatellite instability, right location, and good prognosis; (b) diploid tumors lacking p53 mutations, left and right location, low subchromosomal damage, and bad prognosis; (c) diploid tumors with p53 mutations, left location, high levels of subchromosomal damage, and good prognosis; (d) high aneuploid tumors, p53 mutations, left location, high levels of numerical and structural chromosomal alterations, and bad prognosis; and finally (e) low aneuploid tumors, no p53 mutations, left and right location, low levels of structural chromosomal alterations, and good prognosis. We postulate that these groups represent alternative pathways of tumor progression, each with determinants of aggressiveness. This indicates a need for different prognostic assessments depending on which group the tumor belongs to.

BACKGROUND: Mdm2 is a natural inhibitor of p53 function and its overexpression impairs p53 transcriptional activity. T-->G single-nucleotide polymorphism at position 309 (SNP309) of mdm2 induces overexpression of mdm2, but inhibits p53. OBJECTIVES: To determine whether SNP309 is a risk-modifier polymorphism in colorectal cancer (CRC) and whether tumour selection of P53 mutations are influenced by SNP309. METHODS: Single-stranded conformation polymorphism and automatic sequencing were performed. RESULTS: SNP309 is not associated with the risk of CRC or recurrence of tumours. These data do not over-ride the tumour-selection capabilities of P53 mutations in CRC. However, a significant association with non-dominant-negative P53 mutations (p = 0.02) was found. CONCLUSIONS: MDM2-SNP309 favours tumour selection of non-dominant negative P53 mutations in CRC, which also show an earlier age of tumour onset.

Einleitung: Chemokine sind inflammatorische Moleküle, die sowohl in der akuten als auch der chronischer Leberschädigung eine wichtige Rolle spielen. Das Chemokin PF4 (platelet factor 4, CXCL4) wird in Thrombozyten gespeichert und nach deren Aktivierung freigesetzt. Es konnte bereits gezeigt werden, dass es im Rahmen chronischer Lebererkrankung zu einer vermehrten Akkumulation aktivierter Thrombozyten in der Leber kommt. Die Bedeutung des dabei vermehrt freigesetzten PF4 ist jedoch noch nicht bekannt. Wir untersuchten daher den Einfluss einer genetischen Deletion von PF4 auf die hepatische Fibrosierung in zwei Mausmodellen der chronischen Leberschädigung.

Skeletal muscle is the largest tissue in mammalian organisms and is a key determinant of basal metabolic rate and whole-body energy metabolism. Histone deacetylase 11 (HDAC11) is the only member of the class IV subfamily of HDACs, and it is highly expressed in skeletal muscle, but its role in skeletal muscle physiology has never been investigated. Here, we describe for the first time the consequences of HDAC11 genetic deficiency in skeletal muscle, which results in the improvement of muscle function enhancing fatigue resistance and muscle strength. Loss of HDAC11 had no obvious impact on skeletal muscle structure but increased the number of oxidative myofibers by promoting a glycolytic-to-oxidative muscle fiber switch. Unexpectedly, HDAC11 was localized in muscle mitochondria and its deficiency enhanced mitochondrial content. In particular, we showed that HDAC11 depletion increased mitochondrial fatty acid β-oxidation through activating the AMP-activated protein kinase-acetyl-CoA carboxylase pathway and reducing acylcarnitine levels in vivo, thus providing a mechanistic explanation for the improved muscle strength and fatigue resistance. Overall, our data reveal a unique role of HDAC11 in the maintenance of muscle fiber-type balance and the mitochondrial lipid oxidation. These findings shed light on the mechanisms governing muscle metabolism and may have implications for chronic muscle metabolic disease management.

BACKGROUND: Methotrexate is one of the earliest cytotoxic drugs used in cancer therapy, and despite the isolation of multiple other folate antagonists, methotrexate maintains its significant role as a treatment for different types of cancer and other disorders. The usefulness of treatment with methotrexate is limited by the development of drug resistance, which may be acquired through different ways. To get insights into the mechanisms associated with drug resistance and sensitization we performed a functional analysis of genes deregulated in methotrexate resistant cells, either due to its co-amplification with the dhfr gene or as a result of a transcriptome screening using microarrays. METHODS: Gene expression levels were compared between triplicate samples from either HT29 sensitive cells and resistant to 10-5 M MTX by hybridization to the GeneChip(R) HG U133 PLUS 2.0 from Affymetrix. After normalization, a list of 3-fold differentially expressed genes with a p-value < 0.05 including multiple testing correction (Benjamini and Hochberg false discovery rate) was generated. RT-Real-time PCR was used to validate the expression levels of selected genes and copy-number was determined by qPCR. Functional validations were performed either by siRNAs or by transfection of an expression plasmid. RESULTS: Genes adjacent to the dhfr locus and included in the 5q14 amplicon were overexpressed in HT29 MTX-resistant cells. Treatment with siRNAs against those genes caused a slight reduction in cell viability in both HT29 sensitive and resistant cells. On the other hand, microarray analysis of HT29 and HT29 MTX resistant cells unveiled overexpression of caveolin 1, enolase 2 and PKCalpha genes in resistant cells without concomitant copy number gain. siRNAs against these three genes effectively reduced cell viability and caused a decreased MTX resistance capacity. Moreover, overexpression of E-cadherin, which was found underexpressed in MTX-resistant cells, also sensitized the cells toward the chemotherapeutic agent. Combined treatments targeting siRNA inhibition of caveolin 1 and overexpression of E-cadherin markedly reduced cell viability in both sensitive and MTX-resistant HT29 cells. CONCLUSION: We provide functional evidences indicating that caveolin 1 and E-cadherin, deregulated in MTX resistant cells, may play a critical role in cell survival and may constitute potential targets for coadjuvant therapy.