Biology subjects

Schwertfeger, K. L.

Publications and source records attributed to Schwertfeger, K. L..

4 recordsLinked to original sources

bioRxiv2025

Collagen-Based Tumor Spheroid Model for Investigating Tumor-Macrophage Interactions through Extracellular Matrix Remodeling

Macrophages in the tumor microenvironment (TME) can constitute up to 50% of tumor mass and play a critical role in cancer cell proliferation, invasion, and metastasis. While their contribution to extracellular matrix (ECM) degradation through matrix metalloproteinases (MMPs) has been explored, the role of other macrophage-derived factors in ECM remodeling and their impacts beyond degradation remain poorly understood. Here, we describe the development of a 3D collagen-based tumor spheroid model to investigate the impact of peripheral blood mononuclear cell (PBMC)-derived macrophages on cancer cell-ECM and cancer cell-macrophage interactions within the TME. We observed that cancer cells stimulated PBMC-derived macrophages into an M2-like phenotype and that tumor spheroid conditioned macrophages (TSCMs) shifted cancer cell populations toward phenotypes with greater invasion distances and reduced circularity, indicative of increased malignancy. Such observations can be explained by macrophage-mediated ECM remodeling. Specifically, we demonstrate that TSCMs secreted a variety of soluble factors that are known to contribute to ECM remodeling, including ECM degradation and fiber realignment. These processes collectively create a tumor-favoring environment by loosening the collagen matrix and aligning fibers that serve as invasion tracks for migrating tumor cells that facilitate cancer cell migration and invasion. This model provides a robust platform to study the interactions between cellular and non-cellular components in the TME and to identify the molecular mechanisms underlying cancer progression. These insights may aid in the development of novel therapeutic strategies targeting macrophage-mediated processes in cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/679587v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@17d1f9forg.highwire.dtl.DTLVardef@1a71500org.highwire.dtl.DTLVardef@53deeeorg.highwire.dtl.DTLVardef@510268_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

Deciphering Colorectal Cancer-Hepatocyte Interactions: A Multiomic Platform for Interrogation of Metabolic Crosstalk in the Liver-Tumor Microenvironment

Metabolic reprogramming is a hallmark of cancer, enabling tumor cells to adapt to and exploit their microenvironment for sustained growth. The liver is a common site of metastasis, but the interactions between tumor cells and hepatocytes remain poorly understood. In the context of liver metastasis, these interactions play a crucial role in promoting tumor survival and progression. This study leverages multiomics coverage of the microenvironment via liquid chromatography and high-resolution, high-mass accuracy mass spectrometry-based untargeted metabolomics, 13C-stable isotope tracing, and RNA sequencing to uncover the metabolic impact of co-localized primary hepatocytes and a colon adenocarcinoma cell line, SW480, using a 2D co-culture model. Metabolic profiling revealed disrupted Warburg metabolism with an 80% decrease in glucose consumption and 94% decrease in lactate production by hepatocyte-SW480 co-cultures relative to SW480 control cultures. Decreased glucose consumption was coupled with alterations in glutamine and ketone body metabolism, suggesting a possible fuel switch upon co-culturing. Further, integrated multiomic analysis indicates that disruptions in metabolic pathways, including nucleoside biosynthesis, amino acids, and TCA cycle, correlate with altered SW480 transcriptional profiles and highlight the importance of redox homeostasis in tumor adaptation. Finally, these findings were replicated in 3-dimensional microtissue organoids. Taken together, these studies support a bioinformatic approach to study metabolic crosstalk and discovery of potential therapeutic targets in preclinical models of the tumor microenvironment.

bioinformatics↗

bioRxiv2022

Receptor for Hyaluronan-Mediated Motility (RHAMM) defines an invasive niche associated with tumor progression and predicts poor outcomes in breast cancer patients.

Breast cancer invasion and metastasis result from a complex interplay between tumor cells and the tumor microenvironment (TME). Key oncogenic changes in the TME include aberrant metabolism and subsequent signaling of hyaluronan (HA). Hyaluronan Mediated Motility Receptor (RHAMM, HMMR) is a HA receptor that enables tumor cells to sense and respond to the TME during breast cancer progression. Focused gene expression analysis of an internal breast cancer patient cohort demonstrates increased RHAMM expression correlates with aggressive clinicopathological features. We also develop a 27-gene RHAMM-dependent signature (RDS) by intersecting differentially expressed genes in lymph node positive cases with the transcriptome of a RHAMM-dependent model of cell transformation, which we validate in an independent cohort. We demonstrate RDS predicts for poor survival and associates with invasive pathways. Further analyses using CRISPR/Cas9 generated RHAMM -/- breast cancer cells provide direct evidence that RHAMM promotes invasion in vitro and in vivo. Additional immunohistochemistry studies highlight heterogeneous RHAMM expression, and spatial transcriptomics confirms the RDS emanates from RHAMM-high invasive niches. We conclude RHAMM upregulation leads to the formation of invasive niches, which are enriched in RDS-related pathways that drive invasion and could be targeted to limit invasive progression and improve patient outcomes.

cancer biology↗

bioRxiv2019

An orthogonal c-Cbl recognition mode targets LynA for rapid degradation and builds specificity into the LynA checkpoint

The activity of Src-family kinases (SFKs), which phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs), is critical factor regulating myeloid-cell activation. In a previous paper (Freedman et al., 2015) we showed in macrophages that the SFK LynA is uniquely susceptible to rapid ubiquitin-mediated degradation, functioning as a rheostat regulating ITAM signaling. We now report the mechanism by which LynA is preferentially targeted for degradation and how cell specificity is built into the LynA rheostat. Using genetic and biochemical analysis, we found that the E3 ubiquitin ligase c-Cbl preferentially targets LynA via tyrosine 32 in its unique insert region. This orthogonal mode of c-Cbl recognition depresses the steady-state level of macrophage LynA. Mast cells, however, express little c-Cbl and have correspondingly high steady-state levels of LynA. Upon activation, mast-cell LynA is not rapidly degraded, and SFK-mediated signaling is amplified relative to macrophages. Cell-specific c-Cbl expression therefore builds cell specificity into the LynA checkpoint.

biochemistry↗