| 1. |
- Bozoky, Benedek, et al.
(författare)
-
Stabilization of the classical phenotype upon integration of pancreatic cancer cells into the duodenal epithelium
- 2021
-
Ingår i: Neoplasia. - : Elsevier. - 1522-8002 .- 1476-5586. ; 23:12, s. 1300-1306
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive solid tumors. Based on transcriptomic classifiers, basal-like and classical PDAC subtypes have been defined that differ in prognosis. Cells of both subtypes can coexist in individual tumors; however, the contribution of either clonal heterogeneity or microenvironmental cues to subtype heterogeneity is unclear. Here, we report the spatial tumor phenotype dynamics in a cohort of patients in whom PDAC infiltrated the duodenal wall, and identify the duodenal epithelium as a distinct PDAC microniche. Materials and methods: We used serial multiplex quantitative immunohistochemistry (smq-IHC) for 24 proteins to phenotypically chart PDAC tumor cells in patients whose tumors infiltrated the duodenal epithelium. Additionally, we used a genetically engineered mouse model to study the PDAC cell phenotype in the small intestinal epithelium in a controlled genetic background. Result: We show that pancreatic cancer cells revert to non-destructive growth upon integration into the duodenal epithelium, where they adopt traits of intestinal cell differentiation, associated with phenotypical stabilization of the classical subtype. The integrated tumor cells replace epithelial cells in an adenoma-like manner, as opposed to invasive growth in the submucosa. Finally, we show that this phenomenon is shared between species, by confirming duodenal integration and phenotypic switching in a genetic PDAC mouse model. Discussion: Our results identify the duodenal epithelium as a distinct PDAC microniche and tightly link microenvironmental cue to cancer transcriptional subtypes. The phenomenon of "intestinal mimicry" provides a unique opportunity for the systematic investigation of microenvironmental influences on pancreatic cancer plasticity.
|
|
| 2. |
- Alkasalias, Twana, et al.
(författare)
-
RhoA knockout fibroblasts lose tumor-inhibitory capacity in vitro and promote tumor growth in vivo
- 2017
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 114:8, s. E1413-E1421
-
Tidskriftsartikel (refereegranskat)abstract
- Fibroblasts are a main player in the tumor-inhibitory microenvironment. Upon tumor initiation and progression, fibroblasts can lose their tumor-inhibitory capacity and promote tumor growth. The molecular mechanisms that underlie this switch have not been defined completely. Previously, we identified four proteins over-expressed in cancer-associated fibroblasts and linked to Rho GTPase signaling. Here, we show that knocking out the Ras homolog family member A (RhoA) gene in normal fibroblasts decreased their tumor-inhibitory capacity, as judged by neighbor suppression in vitro and accompanied by promotion of tumor growth in vivo. This also induced PC3 cancer cell motility and increased colony size in 2D cultures. RhoA knockout in fibroblasts induced vimentin intermediate filament reorganization, accompanied by reduced contractile force and increased stiffness of cells. There was also loss of wide F-actin stress fibers and large focal adhesions. In addition, we observed a significant loss of a-smooth muscle actin, which indicates a difference between RhoA knockout fibroblasts and classic cancer-associated fibroblasts. In 3D collagen matrix, RhoA knockout reduced fibroblast branching and meshwork formation and resulted in more compactly clustered tumor-cell colonies in coculture with PC3 cells, which might boost tumor stem-like properties. Coculturing RhoA knockout fibroblasts and PC3 cells induced expression of proinflammatory genes in both. Inflammatory mediators may induce tumor cell stemness. Network enrichment analysis of transcriptomic changes, however, revealed that the Rho signaling pathway per se was significantly triggered only after coculturing with tumor cells. Taken together, our findings in vivo and in vitro indicate that Rho signaling governs the inhibitory effects by fibroblasts on tumor-cell growth.
|
|
| 3. |
- Bozoky, Benedek, et al.
(författare)
-
Decreased decorin expression in the tumor microenvironment
- 2014
-
Ingår i: Cancer Medicine. - : Wiley. - 2045-7634. ; 3:3, s. 485-491
-
Tidskriftsartikel (refereegranskat)abstract
- Decorin is a small leucine-rich proteoglycan, synthesized and deposited by fibroblasts in the stroma where it binds to collagen I. It sequesters several growth factors and antagonizes numerous members of the receptor tyrosine kinase family. In experimental murine systems, it acted as a potent tumor suppressor. Examining the Human Protein Atlas online database of immunostained tissue samples we have surveyed decorin expression in silico in several different tumor types, comparing them with corresponding normal tissues. We found that decorin is abundantly secreted and deposited in normal connective tissue but its expression is consistently decreased in the tumor microenvironment. We developed a software to quantitate the difference in expression. The presence of two closely related proteoglycans in the newly formed tumor stroma indicated that the decreased decorin expression was not caused by the delay in proteoglycan deposition in the newly formed connective tissue surrounding the tumor.
|
|
| 4. |
- Bozoky, Benedek
(författare)
-
Microenvironmental control of malignant growth
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The tumor microenvironment (TME) comprises a complex milieu of different cell types, including cancer associated fibroblasts (CAFs) and immune cells, blood vessels, and the extracellular matrix. Through its interaction with cancer cells, it plays an essential role in cancer invasion and metastasis. The inherent complexity of the TME presents a challenge to study it within experimental model systems. It underscores the importance of complementing such research with observation from human tumor tissues, wherein this intricate complexity is preserved. In Paper IV, we introduce a new software designed to explore the Human Protein Atlas, an online database that includes image data on the protein expression across normal and cancerous tissues from immunohistochemically (IHC) stained tissues. In Paper I, we use this software to identify 12 novel proteins expressed in cancerassociated fibroblasts, four revealing connections to Rho-kinase signaling. We contrast their expression across various tumors and against normal tissue fibroblasts, uncovering expression variability among cancer types and confirm their similarities with the myofibroblastic phenotype. In Paper II, we explore the expression of the proteoglycan Decorin, abundantly present in normal connective tissue and having tumor inhibitory properties, showing its downregulation in the connective tissue surrounding tumors. In Paper III, based on our observations in Paper I of the connection of Rhosignaling in CAFs, we study the effects of knocking out the related RhoA in fibroblasts both in vitro and in vivo models. We demonstrate that the knockout fibroblasts compromise their tumor inhibitory capacity, enhancing cancer cell growth, migration, and metastasis. In Paper VI, we develop a new method for analyzing the extensive data within the Human Protein Atlas by developing a deep-learning-based image classifier. Utilizing a limited training image set, we classify all images available for the prostate, identifying 44 new markers of prostate basal cells. In Paper IV, we explore the influence of the TME on cancer cells by systematically analyzing 20 pancreatic cancer patient samples utilizing an IHC panel. We define shifts in cancer cell phenotype relative to tissue localization, including a transition to a more indolent cancer phenotype, an effect on cancer cell proliferation, and a tendency to normalize the cancer cell phenotype. In conclusion, we developed two new methods that enable us to study protein expression in normal and cancerous tissues by enhancing the capabilities of the HPA. We identified new markers of CAFs and revealed a connection to Rhosignaling. Knocking out the related RhoA in experimental systems resulted in the fibroblasts losing their cancer inhibitory capacity. Finally, we show the remarkable plasticity of cancer cells, demonstrating that their phenotype undergoes significant alterations based on their spatial localization within normal tissue.
|
|
| 5. |
- Bozóky, Benedek, et al.
(författare)
-
Novel signatures of cancer-associated fibroblasts
- 2013
-
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 133:2, s. 286-293
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence indicates the importance of the tumor microenvironment, in particular cancer-associated fibroblasts, in cancer development and progression. In our study, we developed a novel, visually based method to identify new immunohistochemical signatures of these fibroblasts. The method employed a protein list based on 759 protein products of genes identified by RNA profiling from our previous study, comparing fibroblasts with differential growth-modulating effect on human cancers cells, and their first neighbors in the human protein interactome. These 2,654 proteins were analyzed in the Human Protein Atlas online database by comparing their immunohistochemical expression patterns in normal versus tumor-associated fibroblasts. Twelve new proteins differentially expressed in cancer-associated fibroblasts were identified (DLG1, BHLHE40, ROCK2, RAB31, AZI2, PKM2, ARHGAP31, ARHGAP26, ITCH, EGLN1, RNF19A and PLOD2), four of them can be connected to the Rho kinase signaling pathway. They were further analyzed in several additional tumor stromata and revealed that the majority showed congruence among the different tumors. Many of them were also positive in normal myofibroblast-like cells. The new signatures can be useful in immunohistochemical analysis of different tumor stromata and may also give us an insight into the pathways activated in them in their true in vivo context. The method itself could be used for other similar analysis to identify proteins expressed in other cell types in tumors and their surrounding microenvironment.
|
|
