An imbalance in progenitor cell populations reflects tumour progression in breast cancer primary culture models

Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Extrinsic and intrinsic regulation of breast cancer progression - promoting an aggressive phenotype via alterations in cellular populations and subcellular compartments

Breast cancer is one of the most common worldwide cancers. Most breast cancer deaths are caused when tumour cells disseminate from the primary tumour to form metastases in other organs. Many intrinsic and extrinsic mechanisms are involved in progression to a metastatic phenotype. Thus, the aim of this thesis was to study from complementary perspectives key mechanisms involved in altering cellular homeostasis that could promote tumour progression. The first aim was to establish primary culture models from human breast tumour and non-tumour tissues, and to validate functional differences between the models that could underpin tumour progression. Tumour cultures were found to senesce significantly less than nontumour cultures. More importantly, calculation of a novel proliferation : senescence ratio revealed that a stepwise increase in this ratio correlated with a tumour progression paradigm, from non-tumour through low grade tumours and finally high grade tumours. Since there were signs that primary cultures were enriched in progenitor/stem cells, the second aim was to determine whether an imbalance in progenitor populations could associate with clinicopathological parameters of cancer progression. Putative progenitor populations were identified by flow cytometry as either double negative (DN) or double positive (DP) for the epithelial marker EPCAM and the myoepithelial marker CALLA. An increased DN : DP ratio was observed to positively correlate with poor prognosis tumours, namely those of high grade, ER-negativity or HER2 positivity. Therefore these results suggest for the first time that not only the presence of single progenitor populations but also maintenance of a correct balance between them could affect tissue homeostasis and contribute to tumour progression. However, altered self-renewal ability is not the only driver for tumour progression, but also altered migratory properties of tumour cells via proteins such as the lipid raft-affiliated protein CD44. Thus the third aim of this thesis was to dissect the role of lipid rafts in regulating CD44-mediated cell migration. In the metastatic cell line MDA-MB-231, CD44 was found to interact with its migratory binding partner ezrin only outside lipid rafts; that forced retention of CD44 in rafts abolished these interactions and concomitantly reduced cell migration. These results suggest a novel role for lipid rafts in sequestering CD44 to regulate its participation in breast cancer cell migration. Taken together, results presented in this thesis suggest that many complementary cellular events promote breast tumour progression. Some of the novel mechanisms uncovered may represent future targets for developing more powerful treatments against breast cancer.</p

MME mutation in dominant spinocerebellar ataxia with neuropathy (SCA43)

Objective: To identify the causative gene mutation in a 5-generation Belgian family with dominantly inherited spinocerebellar ataxia and polyneuropathy, in which known genetic etiologies had been excluded. Methods: We collected DNA samples of 28 family members, including 7 living affected individuals, whose clinical records were reviewed by a neurologist experienced in ataxia. We combined linkage data of 21 family members with whole exome sequencing in 2 affected individuals to identify shared heterozygous variants mapping to potentially linked regions. Variants were screened for rarity and for predicted damaging effect. A candidate mutation was confirmed by Sanger sequencing and tested for cosegregation with the disease. Results: Affected individuals presented with late-onset sensorimotor axonal polyneuropathy; all but one also had cerebellar ataxia. We identified a variant in the MME gene, p. C143Y, that was absent from control databases, cosegregated with the phenotype, and was predicted to have a strong damaging effect on the encoded protein by all algorithms we used. Conclusions: MME encodes neprilysin (NEP), a zinc-dependent metalloprotease expressed in most tissues, including the central and peripheral nervous systems. The mutated cysteine 143 forms a disulfide bridge, which is 100% conserved in NEP and in similar enzymes. The recent identification of recessive MME mutations in 10 unrelated individuals from Japan with axonal polyneuropathy further supports the causality of the mutation, despite the dominant mode of inheritance and the presence of cerebellar involvement in our study family. Functional studies are needed to identify the mechanisms underlying these differences.SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Development and Progress of Ireland's Biobank Network: Ethical, Legal, and Social Implications (ELSI), Standardized Documentation, Sample and Data Release, and International Perspective

0info:eu-repo/semantics/publishe

Molecular basis of invasion in breast cancer.

Cancer cell invasion involves the breaching of tissue barriers by cancer cells, and the subsequent infiltration of these cells throughout the surrounding tissue. In breast cancer, invasion at the molecular level requires the coordinated efforts of numerous processes within the cancer cell and its surroundings. Accumulation of genetic changes which impair the regulation of cell growth and death is generally accepted to initiate cancer. Loss of cell-adhesion molecules, resulting in a loss in tissue architecture, in parallel with matrix remodelling may also confer a motile or migratory advantage to breast cancer cells. The tumour microenvironment may further influence the behaviour of these cancer cells through expression of cytokines, growth factors, and proteases promoting chemotaxis and invasion. This review will attempt to summarise recent work on these fundamental processes influencing or facilitating breast cancer cell invasion. (Part of a Multi-author Review).Journal ArticleReviewinfo:eu-repo/semantics/publishe

Breast cancer cells: Lipid Rafts as Master Regulators of Breast Cancer Cell Function -- 1

info:eu-repo/semantics/publishe

A novel mechanism of regulating breast cancer cell migration via palmitoylation-dependent alterations in the lipid raft affiliation of CD44.

Most breast cancer-related deaths result from metastasis, a process involving dynamic regulation of tumour cell adhesion and migration. The adhesion protein CD44, a key regulator of cell migration, is enriched in cholesterol-enriched membrane microdomains termed lipid rafts. We recently reported that raft affiliation of CD44 negatively regulates interactions with its migratory binding partner ezrin. Since raft affiliation is regulated by post-translational modifications including palmitoylation, we sought to establish the contribution of CD44 palmitoylation and lipid raft affiliation to cell migration.JOURNAL ARTICLEinfo:eu-repo/semantics/publishe

Maintaining Breast Cancer Specimen Integrity and Individual or Simultaneous Extraction of Quality DNA, RNA, and Proteins from Allprotect-Stabilized and Nonstabilized Tissue Samples

info:eu-repo/semantics/publishe

Maturation of Aluminium Adsorbed Antigens Contributes to the Creation of Homogeneous Vaccine Formulations

Although aluminium-based vaccines have been used for almost over a century, their mechanism of action remains unclear. It is established that antigen adsorption to the adjuvant facilitates delivery of the antigen to immune cells at the injection site. To further increase our understanding of aluminium-based vaccines, it is important to gain additional insights on the interactions between the aluminium and antigens, including antigen distribution over the adjuvant particles. Immuno-assays can further help in this regard. In this paper, we evaluated how established formulation strategies (i.e., sequential, competitive, and separate antigen addition) applied to four different antigens and aluminium oxyhydroxide, lead to formulation changes over time. Results showed that all formulation samples were stable, and that no significant changes were observed in terms of physical-chemical properties. Antigen distribution across the bulk aluminium population, however, did show a maturation effect, with some initial dependence on the formulation approach and the antigen adsorption strength. Sequential and competitive approaches displayed similar results in terms of the homogeneity of antigen distribution across aluminium particles, while separately adsorbed antigens were initially more highly poly-dispersed. Nevertheless, the formulation sample prepared via separate adsorption also reached homogeneity according to each antigen adsorption strength. This study indicated that antigen distribution across aluminium particles is a dynamic feature that evolves over time, which is initially influenced by the formulation approach and the specific adsorption strength, but ultimately leads to homogeneous formulations