Genomics and proteomics approaches to the study of cancer-stroma interactions

Background

The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression.

Methods

The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells.

Results

We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (ARID4A, CALR, GNB2L1, RNF10, SQSTM1, USP9X) were validated by real time PCR.

Conclusions

A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.

Histological study of canine mammary gland during the oestrous cycle

The development of the mammary gland is a puzzling phenomenon and the research on this field has been focussed mostly on the carcinogenesis, with a less goal-oriented concern in basic histology. In order to determine the histological features of normal mammary gland in the different oestrous phases we used 39 non-pregnant female dogs of various breeds and ages. The animals were grouped in: pre-pubertal, pro-oestrous, oestrous, early and late dioestrous, early and late anoestrous phases. Major changes of the canine mammary histology throughout the oestrous cycle were identified in this study. A rudimentary gland with few ducts in the base of the nipple was observed in pre-pubertal female individuals and pubertal pro-oestrous female ones. In the oestrus, small inactive lobules associated with ductal branching and inconspicuous regressive changes were observed, while in early dioestrus, a ductal arborization was present. In late dioestrus, a complete lobuloalveolar differentiation and secretory capacity was achieved. The regressive histological features were abundant on early anoestrus, and markedly generalized on late anoestrus. The regressive process was longer in the more caudal gland pairs. This work provides baseline knowledge of canine mammary gland that may be relevant for interspecies comparative purposes and for pathologists dealing with mammary gland tumours.

Contrasting patterns of phenotypic variation linked to chromosomal inversions in native and colonizing populations of Drosophila subobscura

In fewer than two decades after invading the Americas, the fly Drosophila subobscura evolved latitudinal clines for chromosomal inversion frequencies and wing size that are parallel to the long-standing ones in native Palearctic populations. By sharp contrast, wing shape clines also evolved in the New World, but the relationship with latitude was opposite to that in the Old World. Previous work has suggested that wing trait differences among individuals are partially due to the association between chromosomal inversions and particular alleles which influence the trait under consideration. Furthermore, it is well documented that a few number of effective individuals founded the New World populations, which might have modified the biometrical effect of inversions on quantitative traits. Here we evaluate the relative contribution of chromosomal inversion clines in shaping the parallel clines in wing size and contrasting clines in wing shape in native and colonizing populations of the species. Our results reveal that inversion-size and inversion-shape associations in native and colonizing (South America) populations are generally different, probably due to the bottleneck effect. Contingent, unpredictable evolution was suggested as an explanation for the different details involved in the otherwise parallel wing size clines between Old and New World populations of D. subobscura. We challenge this assertion and conclude that contrasting wing shape clines came out as a correlated response of inversion clines that might have been predicted considering the genetic background of colonizers.