Biology subjects

Akslen, L. A.

Publications and source records attributed to Akslen, L. A..

6 recordsLinked to original sources

bioRxiv2025

Establishment of a humanized patient-derived xenograft mouse model of high-grade serous ovarian cancer for preclinical evaluation of combination immunotherapy

The limited efficacy of immunotherapy in clinical trials in high-grade serous ovarian cancer (HGSOC) may improve by implementing models more reflective of human biology into preclinical studies. To address this, we developed and validated a humanized patient-derived xenograft mouse model of HGSOC. Human hematopoietic stem cells and patient-derived HGSOC were engrafted into immunodeficient mice. The mice were administered durvalumab and/or oleclumab intraperitoneally semi-weekly for five weeks. The immunotherapy was well-tolerated, though no responses occurred. Leukocytes in primary tumors were analyzed immunohistochemically, and circulating T cells were characterized using spectral flow cytometry. All tumors exhibited an immune-excluded immunophenotype. No significant inter-group differences in disease burden, intratumoral leukocyte density, or circulating T-cells were observed. In the durvalumab-only group, tumor burden significantly positively correlated with intratumoral cytotoxic and regulatory T-cell densities. This model reflects human disease biology and clinical findings, providing a robust platform for studying tumor-immune interactions and immunosuppressive mechanisms in HGSOC.

cancer biology↗

bioRxiv2023

Age-related phenotypes in breast cancer: a population- based study

Breast cancer in young (<40 years) is associated with a higher frequency of aggressive tumor types and poor prognosis. It remains unclear if there is an underlying age-related biology that contributes to the unfavorable outcome. We aim to investigate the relationship between age and breast cancer biology, with emphasis on proliferation. Clinico-pathologic information, immunohistochemical markers, and follow-up data were obtained for all patients aged <50 (Bergen cohort-1; n=355) and compared to previously obtained information on patients aged 50-69 (Bergen cohort-2; n=540), who participated in the Norwegian Breast Cancer Screening Program. Data from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) was applied for validation and for analyses of gene expression signatures. Young breast cancer patients presented more aggressive tumor features such as hormone receptor negativity, HER2 positivity, lymph-node metastasis, the HER2-enriched and triple negative subtypes, and shorter survival. Age <40 was significantly associated with features of stemness and higher proliferation (by Ki67), also in molecular subsets. Ki67 showed weaker prognostic value in young patients. We point to aggressive phenotypes, increased tumor cell proliferation and stem-like features in breast cancer of the young. Hence, tumors of young breast cancer patients may have a unique biology, also when accounting for screen/interval differences, that may open for new clinical opportunities, stratifying treatment by age.

pathology↗

bioRxiv2023

Global and single-cell proteomics view of the co-evolution between neural progenitors and breast cancer cells in a co-culture model

Tumor neurogenesis, a process by which new nerves invade tumors, is a growing area of interest in cancer research. Nerve presence has been linked to aggressive features of various solid tumors, including breast and prostate cancer. A recent study suggested that the tumor microenvironment may influence cancer progression through recruitment of neural progenitor cells from the central nervous system. However, the presence of neural progenitors in human breast tumors has not been reported. Here, we investigate the presence of Doublecortin (DCX) and Neurofilament-Light (NFL) co-expressing (DCX+/NFL+) cells in patient breast cancer tissue using Imaging Mass Cytometry. To map the interaction between breast cancer cells and neural progenitor cells further, we created an in vitro model mimicking breast cancer innervation, and characterized using mass spectrometry-based proteomics on the two cell types as they co- evolved in co-culture. Our results indicate stromal presence of DCX+/NFL+ cells in breast tumor tissue from a cohort of 107 patient cases, and that neural interaction contribute to drive a more aggressive breast cancer phenotype in our co-culture models. Our results support that neural involvement plays an active role in breast cancer and warrants further studies on the interaction between nervous system and breast cancer progression.

cancer biology↗

bioRxiv2022

Neurogenesis and angiogenesis are associated features of aggressive breast cancer

The tumor microenvironment (TME) is important for cancer growth and progression. While angiogenesis is an established hallmark of cancer, the role of nerve fibers is less studied. Here, we investigated neurogenesis and angiogenesis in breast cancer and found them to be closely associated. Single-cell based spatial mapping by imaging mass cytometry (IMC) indicated close proximity between neural and vascular structures. Subsequent validation by tissue-based markers of neurogenesis and angiogenesis, supported by proteomics and transcriptomics data of tissues and cell lines, supported a link between these processes. A consolidated neuro-angiogenic signature score was linked to high-grade breast cancer and reduced patient survival, also within the low-grade luminal tumor subgroup. Our findings support that neurogenesis and angiogenesis are related in aggressive breast cancer and might possibly improve tumor stratification and clinical management.

cancer biology↗

bioRxiv2021

PRSS2 promotes tumor growth and progression by repressing Tsp-1 in the tumor microenvironment via binding to LRP1

In the earliest stages of tumor development, epithelial tumors (carcinomas) are physically confined to the area of the tissue in which they form. These nascent lesions (carcinomas in situ) are sequestered from the tissue parenchyma by the basement membrane. Within the tissue parenchyma lie a myriad of cell types comprised of fibroblasts, immune and inflammatory cells and endothelial cells. Upon invasion across the basement membrane and into the tissue parenchyma, tumors must manipulate the expression of pro- and anti-tumorigenic proteins such that pro-tumorigenic factors are produced in excess to anti-tumorigenic proteins. One such anti-tumorigenic protein is Thrombospondin-1 (Tsp-1). We have previously demonstrated that stimulation of Tsp-1 in the tumor microenvironment (TME) potently inhibits tumor growth and progression and in some cases induces tumor regression. Here, we identify a novel tumor-mediated mechanism to repress the expression of Tsp-1 in the TME via secretion of the serine protease PRSS2. We demonstrate that PRSS2 represses Tsp-1, not via its enzymatic activity, but by binding to low-density lipoprotein receptor-related protein 1 (LRP1). These findings describe a novel activity for PRSS2 through binding to LRP1 and represent a potential therapeutic strategy to treat cancer by blocking the PRSS2-mediated repression of Tsp-1.

cancer biology↗

bioRxiv2020

Notch1 regulates breast cancer stem cell function via a non-canonical cleavage-independent pathway

Current treatment of triple negative breast cancer patients is hindered by a high incidence of chemoresistance (30-50%). The prevailing theory is that resistance and subsequent recurrence is driven by cancer stem cells. Unfortunately, the functional characterization of cancer stem cells at the molecular level is still incomplete. We show here, that within the canonical breast cancer stem cell population, a subset of cells characterized by high Notch1 expression possesses the tumor-initiating property associated with cancer stem cells. Moreover, the tumor initiating property of these high Notch1-expressing breast cancer stem cells is mediated by a cleavage independent Notch signaling pathway culminating in the repression of SIRT1. Of note, the Notch1-mediated repression of SIRT1 is required not only for tumor initiation, but also for chemoresistance in breast cancer stem cells. Strikingly, inhibition of SIRT1 obviates the requirement for Notch1, marking the first example of conferring cancer stem cell function by inhibiting the activity of a single protein. We also demonstrate that progenitor-like mammary epithelial cells, which possess both luminal and basal properties, are also characterized by high Notch1 expression and repression of SIRT1 via the non-canonical pathway. These findings provide the first functional mechanistic requirements for tumor initiation by breast cancer stem cells and suggest that activation of the non-canonical Notch1 pathway is hardwired into tumor-initiating progenitor cells and thus a prerequisite for tumor initiation. Statement of SignificanceWe demonstrate that chemoresistant and tumor-initiating properties of breast cancer stem cells are driven by repression of SIRT1 via non-canonical Notch signaling, suggesting a novel therapeutic strategy for triple negative breast cancer.

cancer biology↗