Tumour heterogeneity during the progression of metastatic breast cancer and anti-tumour effects of the novel FAK inhibitor BI 853520 in breast cancer

Over the past decades, reasonable progress has been made in the understanding of breast cancer biology and the treatment of the primary tumour. However, the molecular contribution of multiple cancer cell clones on the various steps of tumour progression is still poorly understood. Aside from that, standard of care treatments, like the chemotherapeutic reagents cyclophosphamide and docetaxel, are rarely able to cure breast cancer patients and the overall survival rates for metastatic disease remain poor. Only in 2018, more than 620,000 women lost their live to breast cancer, mostly due to the presence of tumour heterogeneity, an emerging drug resistance and the formation of secondary lesions. This exemplifies the unmet medical need to an in-depth understanding of tumour heterogeneity during the progression of metastatic breast cancer to finally develop new targeted therapies for this presently incurable disease. The first project has aimed to assess clonal heterogeneity during tumour progression using the MMTV-PyMT mouse model of metastatic breast cancer expressing the Confetti lineage reporter. For this purpose, mammary epithelial cells have been induced to express one of the four Confetti reporter fluorescent proteins. The outgrowth of clonal cell populations has been analysed when the maximum tumour volume comprising all stages (normal, hyperplasia, adenoma, carcinoma, pulmonary metastases) had been reached. The Confetti lineage tracing system initially visualized the emergence of clonal heterogeneity, which culminated in clonal restriction during carcinogenesis and pointed towards a polychromatic metastatic spread. Laser capture microdissection, RNA sequencing and comparative gene expression analysis of various clonal lesions indicated a substantial level of heterogeneity across and also within the various stages of tumour progression. This intra-stage tumour heterogeneity manifested by differences in proliferation, oxidative phosphorylation and cell death and could also be observed in human breast cancer biopsies. This novel understanding of clonal variation and intra-stage heterogeneity needs to be implemented in diagnosis and therapeutic options. In the past years, rising efforts have been made to develop agents targeting molecules and signalling pathways that are specifically present in breast cancer cells. Previous studies have linked an overexpression of focal adhesion kinase (FAK) – a cytoplasmic tyrosine kinase – with the initiation and progression of a wide variety of malignancies, including breast cancer. This correlation of FAK and cancer, together with its role in cell migration, invasion, and proliferation, propose FAK as an attractive target for cancer therapy. In collaboration with a pharmaceutical company, we have assessed and characterized the therapeutic potential and the biological effects of BI 853520, a novel, potent and selective small chemical inhibitor of FAK, in vitro and in several preclinical mouse models of breast cancer. We observed a significant reduction in primary tumour growth driven by an anti-proliferative effect of BI 853520. In contrast, dissecting its influence on metastasis revealed heterogenous effects at different levels of the metastatic cascade. Hence, manipulation of FAK activity with the novel FAK-inhibitor BI 853520 offers a promising anti-tumour approach for breast cancer therapy. In summary, my Ph.D. work delivered new insights into: - The existence of an intra-stage tumour heterogeneity, which is conferred by clonal variations in proliferation, oxidative phosphorylation and cell death. This novel understanding of an intra-stage heterogeneity could have a significant impact on a patient’s diagnosis and therapeutic response and should be implemented in clinical decision-making. - The therapeutic potential and biological effects of the novel FAK-inhibitor BI 853520 in vitro and in preclinical mouse models of breast cancer. This highlighted BI 853520 as a promising anti-proliferative approach for cancer therapy

A multilinear tongue model derived from speech related MRI data of the human vocal tract

We present a multilinear statistical model of the human tongue that captures anatomical and tongue pose related shape variations separately. The model is derived from 3D magnetic resonance imaging data of 11 speakers sustaining speech related vocal tract configurations. The extraction is performed by using a minimally supervised method that uses as basis an image segmentation approach and a template fitting technique. Furthermore, it uses image denoising to deal with possibly corrupt data, palate surface information reconstruction to handle palatal tongue contacts, and a bootstrap strategy to refine the obtained shapes. Our evaluation concludes that limiting the degrees of freedom for the anatomical and speech related variations to 5 and 4, respectively, produces a model that can reliably register unknown data while avoiding overfitting effects. Furthermore, we show that it can be used to generate a plausible tongue animation by tracking sparse motion capture data

Towards the Quantification of Peggy Babcock: Speech Errors and Their Position within the Word

Sequences of similar (i.e., partially identical) words can be hard to say, as indicated by error frequencies, longer reaction and execution times. This study investigates the role of the location of this partial identity and the accompanying differences, i.e. whether errors are more frequent with mismatches in word onsets (top cop), codas (top tock) or both (pop tot). Number of syllables (tippy ticky) and empty positions (top ta) were also varied. Since the gradient nature of errors can be difficult to determine acoustically, articulatory data were investigated. Articulator movements were recorded using electromagnetic articulography, for up to 9 speakers of American English repeatedly producing 2-word sequences to an accelerating metronome. Most word pairs showed more intrusions and greater variability in coda than in onset position, in contrast to the predominance of onset position errors in corpora from perceptual observation.Peer Reviewe

Breast cancer as an example of tumour heterogeneity and tumour cell plasticity during malignant progression

Heterogeneity within a tumour increases its ability to adapt to constantly changing constraints, but adversely affects a patient's prognosis, therapy response and clinical outcome. Intratumoural heterogeneity results from a combination of extrinsic factors from the tumour microenvironment and intrinsic parameters from the cancer cells themselves, including their genetic, epigenetic and transcriptomic traits, their ability to proliferate, migrate and invade, and their stemness and plasticity attributes. Cell plasticity constitutes the ability of cancer cells to rapidly reprogramme their gene expression repertoire, to change their behaviour and identities, and to adapt to microenvironmental cues. These features also directly contribute to tumour heterogeneity and are critical for malignant tumour progression. In this article, we use breast cancer as an example of the origins of tumour heterogeneity (in particular, the mutational spectrum and clonal evolution of progressing tumours) and of tumour cell plasticity (in particular, that shown by tumour cells undergoing epithelial-to-mesenchymal transition), as well as considering interclonal cooperativity and cell plasticity as sources of cancer cell heterogeneity. We review current knowledge on the functional contribution of cell plasticity and tumour heterogeneity to malignant tumour progression, metastasis formation and therapy resistance

Subgroup Splits in Diverse Work Teams : Subgroup Perceptions but Not Demographic Faultlines Affect Team Identification and Emotional Exhaustion

We investigate the relationship between (hypothetical) subgroup splits (i.e., faultlines), subjectively perceived subgroups, and team identification and emotional exhaustion. Based on the job demands-resources model and on self-categorization theory, we propose that faultline strength and perceived subgroups negatively affect emotional exhaustion, mediated by team identification. We further propose that subgroup identification moderates the mediation such that subgroup identification compensates low levels of team identification. We tested our hypotheses with a two-wave questionnaire study in a sample of 105 participants from 48 teams from various contexts. We found an effect of perceived subgroups on emotional exhaustion mediated by team identification, but no direct or indirect effect of faultline strength on emotional exhaustion. We also could not find that subgroup identification moderates the effect of team identification on emotional exhaustion. We discuss the need for further research on the link of subgroup splits in work teams and the rise of psychological health issues and derive that measures to prevent burnout should primarily focus on avoiding or reducing subgroup perception whereas affecting the actual demographic composition of work team should be of lower priority.publishe

A dual role of Irf1 in maintaining epithelial identity but also enabling EMT and metastasis formation of breast cancer cells.

An epithelial to mesenchymal transition (EMT) is an embryonic dedifferentiation program which is aberrantly activated in cancer cells to acquire cellular plasticity. This plasticity increases the ability of breast cancer cells to invade into surrounding tissue, to seed metastasis at distant sites and to resist to chemotherapy. In this study, we have observed a higher expression of interferon-related factors in basal-like and claudin-low subtypes of breast cancer in patients, known to be associated with EMT. Notably, Irf1 exerts essential functions during the EMT process, yet it is also required for the maintenance of an epithelial differentiation status of mammary gland epithelial cells: RNAi-mediated ablation of Irf1 in mammary epithelial cells results in the expression of mesenchymal factors and Smad transcriptional activity. Conversely, ablation of Irf1 during TGFβ-induced EMT prevents a mesenchymal transition and stabilizes the expression of E-cadherin. In the basal-like murine breast cancer cell line 4T1, RNAi-mediated ablation of Irf1 reduces colony formation and cell migration in vitro and shedding of circulating tumor cells and metastasis formation in vivo. This context-dependent dual role of Irf1 in the regulation of epithelial-mesenchymal plasticity provides important new insights into the functional contribution and therapeutic potential of interferon-regulated factors in breast cancer

ROMP-Derived cyclooctene-based monolithic polymeric materials reinforced with inorganic nanoparticles for applications in tissue engineering

Porous monolithic inorganic/polymeric hybrid materials have been prepared via ring-opening metathesis copolymerization starting from a highly polar monomer, i.e., cis-5-cyclooctene-trans-1,2-diol and a 7-oxanorborn-2-ene-derived cross-linker in the presence of porogenic solvents and two types of inorganic nanoparticles (i.e., CaCO3 and calcium hydroxyapatite, respectively) using the third-generation Grubbs initiator RuCl2(Py)2(IMesH2)(CHPh). The physico-chemical properties of the monolithic materials, such as pore size distribution and microhardness were studied with regard to the nanoparticle type and content. Moreover, the reinforced monoliths were tested for the possible use as scaffold materials in tissue engineering, by carrying out cell cultivation experiments with human adipose tissue-derived stromal cells

miR-1199-5p and Zeb1 function in a double-negative feedback loop potentially coordinating EMT and tumour metastasis

Epithelial tumour cells can gain invasive and metastatic capabilities by undergoing an epithelial-mesenchymal transition. Transcriptional regulators and post-transcriptional effectors like microRNAs orchestrate this process of high cellular plasticity and its malignant consequences. Here, using microRNA sequencing in a time-resolved manner and functional validation, we have identified microRNAs that are critical for the regulation of an epithelial-mesenchymal transition and of mesenchymal tumour cell migration. We report that miR-1199-5p is downregulated in its expression during an epithelial-mesenchymal transition, while its forced expression prevents an epithelial-mesenchymal transition, tumour cell migration and invasion in vitro, and lung metastasis in vivo. Mechanistically, miR-1199-5p acts in a reciprocal double-negative feedback loop with the epithelial-mesenchymal transition transcription factor Zeb1. This function resembles the activities of miR-200 family members, guardians of an epithelial cell phenotype. However, miR-1199-5p and miR-200 family members share only six target genes, indicating that, besides regulating Zeb1 expression, they exert distinct functions during an epithelial-mesenchymal transition

Distinct contributions of partial and full EMT to breast cancer malignancy

Epithelial-mesenchymal transition (EMT) is a transient, reversible process of cell de-differentiation where cancer cells transit between various stages of an EMT continuum, including epithelial, partial EMT, and mesenchymal cell states. We have employed Tamoxifen-inducible dual recombinase lineage tracing systems combined with live imaging and 5-cell RNA sequencing to track cancer cells undergoing partial or full EMT in the MMTV-PyMT mouse model of metastatic breast cancer. In primary tumors, cancer cells infrequently undergo EMT and mostly transition between epithelial and partial EMT states but rarely reach full EMT. Cells undergoing partial EMT contribute to lung metastasis and chemoresistance, whereas full EMT cells mostly retain a mesenchymal phenotype and fail to colonize the lungs. However, full EMT cancer cells are enriched in recurrent tumors upon chemotherapy. Hence, cancer cells in various stages of the EMT continuum differentially contribute to hallmarks of breast cancer malignancy, such as tumor invasion, metastasis, and chemoresistance.ISSN:1534-5807ISSN:1878-155