EDIL3 promotes epithelial-mesenchymal transition and paclitaxel resistance through its interaction with integrin αVβ3 in cancer cells

Epithelial-mesenchymal transition (EMT) has recently been associated with tumor progression, metastasis, and chemotherapy resistance in several tumor types. We performed a differential gene expression analysis comparing paclitaxel-resistant vs. paclitaxel-sensitive breast cancer cells that showed the upregulation of EDIL3 (EGF Like Repeats and Discoidin I Like Domains Protein 3). This gene codifies an extracellular matrix protein that has been identified as a novel regulator of EMT, so we studied its role in tumor progression and paclitaxel response. Our results demonstrated that EDIL3 expression levels were increased in paclitaxel-resistant breast and prostate cancer cells, and in subsets of high-grade breast and prostate tumors. Moreover, we observed that EDIL3 modulated the expression of EMT markers and this was impaired by cilengitide, which blocks the EDIL3-integrin αVβ3 interaction. EDIL3 knockdown reverted EMT and sensitized cells to paclitaxel. In contrast, EDIL3 overexpression or the culture of cells in the presence of EDIL3-enriched medium induced EMT and paclitaxel resistance. Adding cilengitide resensitized these cells to paclitaxel treatment. In summary, EDIL3 may contribute to EMT and paclitaxel resistance through autocrine or paracrine signaling in cancer cells. Blockade of EDIL3-integrin αVβ3 interaction by cilengitide restores sensitivity to paclitaxel and reverts EMT in paclitaxel-resistant cancer cells. Combinations of cilengitide and taxanes could be beneficial in the treatment of subsets of breast and prostate cancers.

Specific detection of fission yeast primary septum reveals septum and cleavage furrow ingression during early anaphase independent of mitosis completion

It is widely accepted in eukaryotes that the cleavage furrow only initiates after mitosis completion. In fission yeast, cytokinesis requires the synthesis of a septum tightly coupled to cleavage furrow ingression. The current cytokinesis model establishes that simultaneous septation and furrow ingression only initiate after spindle breakage and mitosis exit. Thus, this model considers that although Cdk1 is inactivated at early-anaphase, septation onset requires the long elapsed time until mitosis completion and full activation of the Hippo-like SIN pathway. Here, we studied the precise timing of septation onset regarding mitosis by exploiting both the septum-specific detection with the fluorochrome calcofluor and the high-resolution electron microscopy during anaphase and telophase. Contrarily to the existing model, we found that both septum and cleavage furrow start to ingress at early anaphase B, long before spindle breakage, with a slow ingression rate during anaphase B, and greatly increasing after telophase onset. This shows that mitosis and cleavage furrow ingression are not concatenated but simultaneous events in fission yeast. We found that the timing of septation during early anaphase correlates with the cell size and is regulated by the corresponding levels of SIN Etd1 and Rho1. Cdk1 inactivation was directly required for timely septation in early anaphase. Strikingly the reduced SIN activity present after Cdk1 loss was enough to trigger septation by immediately inducing the medial recruitment of the SIN kinase complex Sid2-Mob1. On the other hand, septation onset did not depend on the SIN asymmetry establishment, which is considered a hallmark for SIN activation. These results recalibrate the timing of key cytokinetic events in fission yeast; and unveil a size-dependent control mechanism that synchronizes simultaneous nuclei separation with septum and cleavage furrow ingression to safeguard the proper chromosome segregation during cell division.

Fission yeast cytokinesis requires the invagination of the equatorial plasma membrane (cleavage furrow ingression) coupled to the synthesis of a special wall structure named septum (septation). Despite Cdk1 kinase is inactivated in early anaphase, it is believed that cleavage furrow ingression and septation onset require anaphase progression and mitosis completion, only initiating after the complete activation of the Hippo-like septation initiation network (SIN) after telophase onset. Here, we studied the precise timing of septation start with respect to mitosis through specific septum-staining and electron microscopy. We found that septum and cleavage furrow ingression initiate in early anaphase, showing first a slow ingression rate during anaphase B, and increasing to a fast ingression rate after telophase onset. Thus, mitosis and cleavage furrow ingression are not concatenated but simultaneous events in fission yeast. The timing of septation correlated with cell size and depended on the level of cytoplasmic activators like SIN Etd1 and Rho1. We further analyzed the mitotic mechanisms that control the septation onset during early anaphase. Cdk1 directly regulated the timing of septation onset during early anaphase, and the low SIN activity present after Cdk1 inactivation was enough to trigger septation. Globally, these results recalibrate the timing of the main cytokinetic events of fission yeast and reveal a size-dependent control mechanism that synchronizes simultaneous nuclei separation with septum and cleavage furrow ingression.

Is staphylococci population from milk of healthy goats safe?

The aim of this study was to assess the species and the genetic diversity of the staphylococci population in raw milk from healthy goats. Isolates representative of all genotypes were screened for their potential pathogenicity by the occurrence of some relevant safety-related properties, such as antibiotic resistance, presence of virulence factor genes, biofilm formation ability and biogenic amine production. A total of 314 staphylococci were isolated, and randomly amplified polymorphic DNA-PCR analysis displayed 48 genotypes. Isolates were identified as belonging to S. epidermidis (87.5%), S. caprae (6.2%), S. aureus (4.2%) and S. simulans (2.1%) species. The antibiotic resistance varied strongly with strains, with S. epidermidis and S. aureus strains showing resistance to more number of antibiotics. A high occurrence of strains harbouring hemolysin genes was also found in both species. On the contrary, none of the strains assayed harboured enterotoxin or amino acid decarboxylase genes, and, although a moderate or high biofilm formation was observed in 29% of the strains, they did not harbour icaA or icaD genes. This study gives a first and extensive picture of safety-related properties within Staphylococcus species isolated from milk of healthy goats, displaying that these species can act as a reservoir for spreading genes related to safety.

Genetic analysis of FAM46A in Spanish families with autosomal recessive retinitis pigmentosa: characterisation of novel VNTRs

Retinitis pigmentosa (RP) is a group of retinal dystrophies characterised primarily by rod photoreceptor cell degeneration. Exhibiting great clinical and genetic heterogeneity, RP be inherited as an autosomal dominant (ad) and recessive (ar), X-linked (xl) and digenic disorder. RP25, a locus for arRP, was mapped to chromosome 6p12.1-q14.1 where several retinal dystrophy loci are located. A gene expressed in the retina, FAM46A, mapped within the RP25 locus, and computational data revealed its involvement in retinal signalling pathways. Therefore, we chose to perform molecular evaluation of this gene as a good candidate in arRP families linked to the RP25 interval. A comprehensive bioinformatic and retinal tissue expression characterisation of FAM46A was performed, together with mutation screening of seven RP25 families. Herein we present 4 novel sequence variants, of which one is a novel deletion within a low complexity region close to the initiation codon of FAM46A. Furthermore, we have characterised for the first time a coding tandem variation in the Caucasian population. This study reports on bioinformatic and moleculardata for the FAM46A gene that may give a wider insight into the putative function of this gene and its pathologic relevance to RP25 and other retinal diseases mapping within the 6q chromosomal interval.

Linkage validation of RP25 Using the 10K genechip array and further refinement of the locus by new linked families

Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal dystrophies, characterised by rod photoreceptor cell degeneration with autosomal recessive RP (arRP) as the commonest form worldwide. To date, a total of 26 loci have been reported for arRP, each having a prevalence of 1-5%, except for the RP25 locus which was identified as the genetic cause of 14% of arRP cases in Spain. In order to validate the original linkage of RP25, we undertook a total genome scan using the 10K GeneChip mapping array on three of the previously linked families. The data obtained supported the initial findings of linkage. Additionally, linkage analysis in 18 newly ascertained arRP families was performed using microsatellite markers spanning the chromosome 6p12.1-q15 interval. Five out of the 18 families showed suggestive evidence of linkage to RP25, hence supporting the high prevalence of this locus in the Spanish population. Furthermore, the finding of a crossover in one of these families is likely to have refined the disease interval from the original 16 cM to only a 2.67 cM region between D6S257 and D6S1557.