| 1. |
- Bartoschek, Michael
(författare)
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Exploring functional subsets of cancer-associated fibroblasts
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The tumor microenvironment consists of several interacting cell types. Cancer research focssed mainly on the malignant cell in the past. The importance of the tumor microenvironment is increasingly appreciated, as endothelial cells and immune cells were identified as targets for anti-tumor therapy. Targeted therapy against cancer-associated fibroblasts (CAFs) are not in clinical use for the treatment of carcinomas, even though CAFs are involved in many tumor-supporting processes. CAFs are mesenchymal stromal cells and generate and modulate the extracellular matrix (ECM), which provides physical stability to the growing tumor. CAFs can alter cell-to-cell communication within the tumor microenvironment and thereby influence the immune reaction to cancer cells, the response to cancer therapy and the tumor metabolism.Breast cancer is the most common malignant disease and second most common reason for cancer-related death in women. Despite advancements in the treatment of breast cancer, some aggressive forms remain hard to treat.In the first paper we investigated the effect of complement oligomeric matrix protein (COMP) on breast cancer. Epithelial COMP expression is associated with reduced survival in breast cancer patients.We showed that COMP resolves endoplasmic reticulum stress and deregulates the cell metabolism, causing increased growth and metastasis in vivo. We propose COMP expression as a potential prognostic marker in breast cancer.In the second part of the thesis we analyzed the importance of platelet-derived growth factor (PDGF) signaling in solid tumors in general, and the effect of PDGF-CC signaling in breast cancer in particular. We showed that PDGF-CC signaling to CAFs and the subsequent release of CAF-derived stanniocalcin 1, hepatocyte growth factor, and insulin growth factor binding protein 3 maintain a basal-like phenotype in breast cancer. Genetic and pharmacologic disruption of this commuication loop resulted in conversion of a hormone receptor-negative into a hormone receptor-positive state, causing enhanced sensitivity to endocrine therapy in previously resistant tumors. We conclude that the breast cancer subtype is in part under the control of the tumor microenvironment.CAFs have many different functions in the tumor microenvironment and different origins for CAFs have been suggested. In the last paper we used single-cell RNA-sequencing of 786 mesenchymal cells derived from tumors of the MMTV-PyMT mouse model of breast cancer, to identify subclasses of CAFs in an unbiased approach. We detected and confirmed the existence of four subclasses that potentially derive from three different origins. Based on differential gene expression analysis we assigned functional properties to each CAF subgroup. Gene profiles of the main CAF subgroups held independent prognostic capability in large clinical cohorts. We showed that an in depth investigation of cellular constituents of the tumor microenvironment with increased resolution, can reveal a higher order of cellular organization in malignant disease.
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| 2. |
- Bartoschek, Michael, et al.
(författare)
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PDGF family function and prognostic value in tumor biology
- 2018
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 503:2, s. 984-990
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Tidskriftsartikel (refereegranskat)abstract
- The development and progression of a tumor depends on the close interaction of malignant cells and the supportive and suppressive tumor microenvironment. Paracrine signaling enables tumor cells to shape the surrounding tissue in order to decrease recognition by the immune system, attract blood vessels to fuel growth, change metabolic programs, and induce wound healing programs. In this study, we investigate the role of the platelet-derived growth factor (PDGF) family members PDGFA, PDGFB, PDGFC and PDGFD and their cognate tyrosine kinase receptors PDGFRA and PDGFRB, using publicly available data from The Cancer Genome Atlas and the Human Protein Atlas. Large scale analysis of expression correlation in RNA sequencing data from 7616 samples derived from 16 tumor types, revealed conserved functional programs in PDGF signaling in the majority of solid tumor types. Besides the well-known effects of PDGF signaling in mesenchymal cells, our analyses revealed a potential role of PDGF signaling in the composition of the immune microenvironment. We furthermore derived gene signatures with increased prognostic value for each PDGF family member. This study emphasizes the potential to impinge on specific paracrine signaling events to interfere with the crosstalk between malignant cells and their microenvironment.
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| 3. |
- Bartoschek, Michael, et al.
(författare)
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Spatially and functionally distinct subclasses of breast cancer-associated fibroblasts revealed by single cell RNA sequencing
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Cancer-associated fibroblasts (CAFs) are a major constituent of the tumor microenvironment, although their origin and roles in shaping disease initiation, progression and treatment response remain unclear due to significant heterogeneity. Here, following a negative selection strategy combined with single-cell RNA sequencing of 768 transcriptomes of mesenchymal cells from a genetically engineered mouse model of breast cancer, we define three distinct subpopulations of CAFs. Validation at the transcriptional and protein level in several experimental models of cancer and human tumors reveal spatial separation of the CAF subclasses attributable to different origins, including the peri-vascular niche, the mammary fat pad and the transformed epithelium. Gene profiles for each CAF subtype correlate to distinctive functional programs and hold independent prognostic capability in clinical cohorts by association to metastatic disease. In conclusion, the improved resolution of the widely defined CAF population opens the possibility for biomarker-driven development of drugs for precision targeting of CAFs.
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| 4. |
- Quandt, Jasmin, et al.
(författare)
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Long-peptide vaccination with driver gene mutations in p53 and Kras induces cancer mutation-specific effector as well as regulatory T cell responses
- 2018
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Ingår i: OncoImmunology. - 2162-4011. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- Mutated proteins arising from somatic mutations in tumors are promising targets for cancer immunotherapy. They represent true tumor-specific antigens (TSAs) as they are exclusively expressed in tumors, reduce the risk of autoimmunity and are more likely to overcome tolerance compared to wild-type (wt) sequences. Hence, we designed a panel of long peptides (LPs, 28–35 aa) comprising driver gene mutations in TP35 and KRAS frequently found in gastrointestinal tumors to test their combined immunotherapeutic potential. We found increased numbers of T cells responsive against respective mutated and wt peptides in colorectal cancer patients that carry the tested mutations in their tumors than patients with other mutations. Further, active immunization of HLA(-A2/DR1)-humanized mice with mixes of the same mutated LPs yielded simultaneous, polyvalent CD8+/CD4+ T cell responses against the majority of peptides. Peptide-specific T cells possessed a multifunctional cytokine profile with CD4+ T cells showing a TH1-like phenotype. Two mutated peptides (Kras[G12V], p53[R248W]) induced significantly higher T cell responses than corresponding wt sequences and comprised HLA-A2/DR1-restricted mutated epitopes. However, vaccination with the same highly immunogenic LPs strongly increased systemic regulatory T cells (Treg) numbers in a syngeneic sarcoma model over-expressing these mutated protein variants and resulted in accelerated tumor outgrowth. In contrast, tumor outgrowth was delayed when vaccination was directed against tumor-intrinsic Kras/Tp53 mutations of lower immunogenicity. Conclusively, we show that LP vaccination targeting multiple mutated TSAs elicits polyvalent, multifunctional, and mutation-specific effector T cells capable of targeting tumors. However, the success of this therapeutic approach can be hampered by vaccination-induced, TSA-specific Tregs.
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| 5. |
- Roswall, Pernilla, et al.
(författare)
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Microenvironmental control of breast cancer subtype elicited through paracrine platelet-derived growth factor-CC signaling
- 2018
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 24, s. 463-473
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Tidskriftsartikel (refereegranskat)abstract
- Breast tumors of the basal-like, hormone receptor-negative subtype remain an unmet clinical challenge, as there is high rate of recurrence and poor survival in patients following treatment. Coevolution of the malignant mammary epithelium and its underlying stroma instigates cancer-associated fibroblasts (CAFs) to support most, if not all, hallmarks of cancer progression. Here we delineate a previously unappreciated role for CAFs as determinants of the molecular subtype of breast cancer. We identified paracrine crosstalk between cancer cells expressing platelet-derived growth factor (PDGF)-CC and CAFs expressing the cognate receptors in human basal-like mammary carcinomas. Genetic or pharmacological intervention of PDGF-CC activity in mouse models of cancer resulted in conversion of basal-like breast cancers into a hormone receptor-positive state that enhanced sensitivity to endocrine therapy in previously resistant tumors. We conclude that specification of breast cancer to the basal-like subtype is under microenvironmental control and is therapeutically actionable.
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