Differential stromal reprogramming in benign and malignant naturally occurring canine mammary tumours identifies disease-modulating stromal components

While cancer-associated stroma (CAS) in malignant tumours is well described, stromal changes in benign forms of naturally occurring tumours remain poorly characterized. Spontaneous canine mammary carcinomas (mCA) are viewed as excellent models of human mCA. We have recently reported highly conserved stromal reprogramming between canine and human mCA based on transcriptome analysis of laser-capture-microdissected FFPE specimen. To identify stromal changes between benign and malignant mammary tumours, we have analysed matched normal and adenoma-associated stroma (AAS) from 13 canine mammary adenomas and compared them to previous data from 15 canine mCA. Our analyses reveal distinct stromal reprogramming even in small benign tumours. While similarities between AAS and CAS exist, the stromal signature clearly distinguished adenomas from mCA. The distinction between AAS and CAS is further substantiated by differential enrichment in several hallmark signalling pathways as well as differential abundance in cellular composition. Finally, we identify COL11A1, VIT, CD74, HLA-DRA, STRA6, IGFBP4, PIGR, and TNIP1 as strongly discriminatory stromal genes between adenoma and mCA, and demonstrate their prognostic value for human breast cancer. Given the relevance of canine CAS as a model for the human disease, our approach identifies disease-modulating stromal components with implications for both human and canine breast cancer

Nucleolus: the fascinating nuclear body

Nucleoli are the prominent contrasted structures of the cell nucleus. In the nucleolus, ribosomal RNAs are synthesized, processed and assembled with ribosomal proteins. RNA polymerase I synthesizes the ribosomal RNAs and this activity is cell cycle regulated. The nucleolus reveals the functional organization of the nucleus in which the compartmentation of the different steps of ribosome biogenesis is observed whereas the nucleolar machineries are in permanent exchange with the nucleoplasm and other nuclear bodies. After mitosis, nucleolar assembly is a time and space regulated process controlled by the cell cycle. In addition, by generating a large volume in the nucleus with apparently no RNA polymerase II activity, the nucleolus creates a domain of retention/sequestration of molecules normally active outside the nucleolus. Viruses interact with the nucleolus and recruit nucleolar proteins to facilitate virus replication. The nucleolus is also a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm by nucleolus disruption. The nucleolus plays several crucial functions in the nucleus: in addition to its function as ribosome factory of the cells it is a multifunctional nuclear domain, and nucleolar activity is linked with several pathologies. Perspectives on the evolution of this research area are proposed

Fusion proteins comprising the catalytic domain of mutansucrase and a starch-binding domain can alter the morphology of amylose-free potato starch granules during biosynthesis

It has been shown previously that mutan can be co-synthesized with starch when a truncated mutansucrase (GtfICAT) is directed to potato tuber amyloplasts. The mutan seemed to adhere to the isolated starch granules, but it was not incorporated in the starch granules. In this study, GtfICAT was fused to the N- or C-terminus of a starch-binding domain (SBD). These constructs were introduced into two genetically different potato backgrounds (cv. Kardal and amf), in order to bring GtfICAT in more intimate contact with growing starch granules, and to facilitate the incorporation of mutan polymers in starch. Fusion proteins of the appropriate size were evidenced in starch granules, particularly in the amf back- ground. The starches from the various GtfICAT/ SBD transformants seemed to contain less mutan than those from transformants with GtfICAT alone, suggesting that the appended SBD might inhibit the activity of GtfICAT in the engineered fusion proteins. Scanning electron microscopy showed that expression of SBD-GtfICAT resulted in alterations of granule morphology in both genetic backgrounds. Surprisingly, the amf starches con- taining SBD-GtfICAT had a spongeous appearance, i.e., the granule surface contained many small holes and grooves, suggesting that this fusion protein can interfere with the lateral interactions of amylopectin sidechains. No differences in phys- ico-chemical properties of the transgenic starches were observed. Our results show that expression of granule-bound and ‘‘soluble’’ GtfICAT can affect starch biosynthesis differently