Biology subjects

Kuczek, D. E.

Publications and source records attributed to Kuczek, D. E..

3 recordsLinked to original sources

bioRxiv2026

Collagen type I promotes pancreatic tumor growth and limits immune cell infiltration

Solid tumors are often characterized by a dense extracellular matrix (ECM) that contributes to increased tissue stiffness. Collagen type I is the main component of the ECM and its abundance in tumors is frequently associated with poor prognosis. In vitro studies suggest that a high collagen density promotes tumor invasion and modulates immune responses. However, recent in vivo findings have questioned the pro-tumorigenic role of collagen type I. In this study, we investigate the role of collagen for pancreatic tumor growth and immune cell infiltration using conditional collagen type I knockout mice and transgenic collagenase-resistant mice. Preventing collagen type I significantly reduces intratumoral collagen content and tumor growth. This reduction is accompanied increased infiltration of natural killer (NK) cells, a higher CD8/CD4 T cell ratio, and decreased numbers of monocytic myeloid-derived suppressor cells (MDSCs). Conversely, collagenase-resistant mice develop collagen-dense tumors and display enhanced tumor growth. These mice also generally exhibit opposing effects on cell infiltration, including a lower CD8/CD4 ratio and increased MDSC abundance. These findings are further supported by analyses of publicly available human cancer datasets, which confirm an association between collagen type I levels and immune cell infiltration. Overall, our results demonstrate a pronounced pro-tumorigenic role of collagen type I in pancreatic cancer, which is associated with modulation of the tumor immune microenvironment. This study highlights the importance of extracellular matrix components as key regulators of tumor progression and anti-tumor immunity.

cancer biology↗

bioRxiv2019

Collagen Density Modulates the Immunosuppressive Functions of Tumor-Associated Macrophages

Tumor-associated macrophages (TAMs) support tumor growth by suppressing the activity of tumor infiltrating T cells. Consistently, the number of TAMs has been correlated with a poor prognosis of cancer. The immunosuppressive TAMs are also considered a major limitation for the efficacy of cancer immunotherapy. However, the molecular reason behind the acquisition of an immunosuppressive TAM phenotype is still not completely understood. During solid tumor growth, the extracellular matrix (ECM) is degraded and substituted with a tumor specific collagen-rich ECM. The collagen density of this tumor ECM has been associated with a poor prognosis of several cancers, but the underlying reason for this correlation is not well understood. Here, we have investigated whether the collagen density could modulate the immunosuppressive activity of TAMs and thereby promote tumor progression.\n\nIn this study, the macrophage cell line RAW 264.7 was 3D cultured in collagen matrices of low- and high collagen densities mimicking healthy and tumor tissue, respectively. The effects of collagen density on macrophage phenotype and function were investigated by confocal microscopy, flow cytometry, RNA sequencing, qRT-PCR, and ELISA analysis. To investigate the effect of collagen density on the immune modulatory activity of macrophages, co-culture assays with primary T cells to assess T cell chemotaxis and proliferation were conducted. Lastly, the effects of collagen density on primary cells were investigated using murine bone-marrow derived macrophages (BMDMs) and TAMs isolated from murine 4T1 breast tumors.\n\nCollagen density did not affect the proliferation, viability or morphology of macrophages. However, whole-transcriptome analysis revealed a striking response to the surrounding collagen density including the differential regulation of many immune regulatory genes and genes encoding chemokines. The transcriptional changes in RAW 264.7 macrophages were shown to be similar in murine BMDMs and TAMs. Strikingly, the collagen density-induced changes in the gene expression profile had functional consequences for the macrophages. Specifically, macrophages cultured in high density collagen were less efficient at attracting cytotoxic T cells and also capable of inhibiting T cell proliferation to a greater extent than macrophages cultured in low density collagen.\n\nOur study demonstrates that a high collagen density can instruct TAMs to acquire an immunosuppressive phenotype. This could be one of the mechanisms decreasing the efficacy of immunotherapy and linking increased collagen density to poor patient prognosis.

immunology↗

bioRxiv2018

Collagen density regulates the activity of tumor-infiltrating T cells

BackgroundTumor progression is accompanied by dramatic remodeling of the surrounding extracellular matrix leading to the formation of a tumor-specific ECM, which is often more collagen-rich and of increased stiffness. The altered ECM of the tumor supports cancer growth and metastasis, but it is unknown if this effect involves modulation of T cell activity. To investigate if a high-density tumor-specific ECM could influence the ability of T cells to kill cancer cells, we here studied how T cells respond to 3D culture in different collagen densities.\n\nMethodsT cells cultured in 3D conditions surrounded by a high or low collagen density were imaged using confocal fluorescent microscopy. The effects of the different collagen densities on T cell proliferation, survival, and differentiation were examined using flow cytometry. Cancer cell proliferation in similar 3D conditions was also measured. Triple-negative breast cancer specimens were analyzed for the number of infiltrating CD8+ T cells and for the collagen density. Whole-transcriptome analyses were applied to investigate in detail the effects of collagen density on T cells. Computational analyses were used to identify transcription factors involved in the collagen density-induced gene regulation. Observed changes were confirmed by qRT-PCR analysis.\n\nResultsT cell proliferation was significantly reduced in a high-density matrix compared to a low-density matrix and prolonged culture in a high-density matrix led to a higher ratio of CD4+ to CD8+ T cells. The proliferation of cancer cells was unaffected by the surrounding collagen-density. Consistently, we observed a reduction in the number of infiltrating CD8+ T-cells in mammary tumors with high collagen-density indicating that collagen-density has a role in regulating T cell abundance in human breast cancer.\n\nWhole-transcriptome analysis of 3D-cultured T cells revealed that a high-density matrix induces downregulation of cytotoxic activity markers and upregulation of regulatory T cell markers. These transcriptional changes were predicted to involve autocrine TGF-B signaling and they were accompanied by an impaired ability of tumor-infiltrating T cells to kill autologous cancer cells.\n\nConclusionsOur study identifies a new immune modulatory mechanism, which could be essential for suppression of T cell activity in the tumor microenvironment.

immunology↗