The roles of collagen synthesis enzymes in tumorigenesis and metastasis, with focus on tumor stroma and pancreatic cancer as a model
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Leena Palotie Hall 101A, Aapistie 5A, Oulu
Topic of the dissertation
The roles of collagen synthesis enzymes in tumorigenesis and metastasis, with focus on tumor stroma and pancreatic cancer as a model
Doctoral candidate
Master of Medical Science Linda Birgisdóttir
Faculty and unit
University of Oulu Graduate School, Faculty of Biochemistry and Molecular Medicine, ECM and hypoxia
Subject of study
Biochemistry and molecular medicine
Opponent
Professor Malin Sund, University of Helsinki
Custos
Professor Johanna Myllyharju, University of Oulu
The roles of collagen synthesis enzymes in tumorigenesis and metastasis, with focus on tumor stroma and pancreatic cancer as a model
Pancreatic ductal adenocarcinoma (PDAC) is a highly deadly disease with a hallmark of dense stroma consisting of collagen-rich extracellular matrix (ECM). Tumor microenvironment, including the ECM, is an important regulator of tumor growth. Cancer-associated fibroblasts are the most abundant cell type in the tumor stroma and are mainly responsible for the ECM remodeling during cancer progression. Collagen prolyl 4-hydroxylases (C-P4Hs) and lysyl hydroxylases (LHs) have important roles in collagen synthesis. In this project, we focused our studies on the effects of the lack of one of the following collagen-modifying enzymes: C-P4H isoenzyme I (P4ha1), LH1 (Plod1) or LH2 (Plod2), on fibroblasts using knockout mouse embryonic fibroblasts (MEFs) as a model. We also studied the roles of these enzymes in pancreatic tumor stroma by using C-P4H and LH deficient mouse lines and syngeneic PDAC cells.
P4ha1-/- MEFs were more contractile in type I collagen gel and less apoptotic than their wild-type (WT) counterparts. Plod1-/- MEFs tended to proliferate more in hypoxia and contract more in type I collagen gel. Also, Plod2-/- MEFs were more contractile and in addition migrated and adhered better than their WT counterparts.
In vivo studies were done with Plod1-/-, P4ha2-/- and compound P4ha1+/-;P4ha2-/- mouse lines. We used an intrasplenic injection model with murine KPC PDAC cells to achieve liver metastases in all the mouse lines. In addition, we used an orthotopic pancreatic cancer model with the KPC cells in the P4ha2-/- and compound P4ha1+/-;P4ha2-/- mouse lines and a subcutaneous mouse tumor model with murine Pan02 PDAC cells in the Plod1-/- mice.
The P4ha1+/-;P4ha2-/- mice had less metastatic growth in the liver with decreased collagen content. However, no difference was seen in the growth of orthotopic tumors. The Plod1-/- mice had increased growth both in liver metastasis and subcutaneous tumors, but only the subcutaneous tumors had less total collagen, while the liver metastases had less fibrillar collagen and an increase in macrophage and a decrease in T cell counts compared to the WT mice.
In this thesis, we show that the C-P4H and LH isoenzymes have specific roles in fibroblasts and in the PDAC stroma. The data provide potential novel therapeutic targets as new treatment strategies are desperately needed to treat pancreatic cancer.
P4ha1-/- MEFs were more contractile in type I collagen gel and less apoptotic than their wild-type (WT) counterparts. Plod1-/- MEFs tended to proliferate more in hypoxia and contract more in type I collagen gel. Also, Plod2-/- MEFs were more contractile and in addition migrated and adhered better than their WT counterparts.
In vivo studies were done with Plod1-/-, P4ha2-/- and compound P4ha1+/-;P4ha2-/- mouse lines. We used an intrasplenic injection model with murine KPC PDAC cells to achieve liver metastases in all the mouse lines. In addition, we used an orthotopic pancreatic cancer model with the KPC cells in the P4ha2-/- and compound P4ha1+/-;P4ha2-/- mouse lines and a subcutaneous mouse tumor model with murine Pan02 PDAC cells in the Plod1-/- mice.
The P4ha1+/-;P4ha2-/- mice had less metastatic growth in the liver with decreased collagen content. However, no difference was seen in the growth of orthotopic tumors. The Plod1-/- mice had increased growth both in liver metastasis and subcutaneous tumors, but only the subcutaneous tumors had less total collagen, while the liver metastases had less fibrillar collagen and an increase in macrophage and a decrease in T cell counts compared to the WT mice.
In this thesis, we show that the C-P4H and LH isoenzymes have specific roles in fibroblasts and in the PDAC stroma. The data provide potential novel therapeutic targets as new treatment strategies are desperately needed to treat pancreatic cancer.
Last updated: 15.3.2024