Biology subjects

McLaughlin, S. L.

Publications and source records attributed to McLaughlin, S. L..

4 recordsLinked to original sources

bioRxiv2021

Cell Communication Network factor 4 promotes tumor-induced immunosuppression in melanoma

Immune cell composition within the tumor microenvironment is regulated by tumor-derived factors. Cell Communication Network factor 4 (CCN4/WISP1) is a matricellular protein secreted by cancer cells that promotes metastasis by inducing the epithelial-mesenchymal transition. While metastatic dissemination limits patient survival, the absence of anti-tumor immunity also associates with poor patient out-comes with recent work suggesting these two clinical correlates are linked. Motivated by finding that CCN4 was associated with a dampened anti-tumor immune contexture in patients diagnosed with primary melanoma, we tested for a direct causal link by knocking out CCN4 (CCN4-KO) in the B16F0 and YUMM1.7 mouse models for melanoma. Tumor growth was significantly reduced when CCN4-KO melanoma cells were implanted subcutaneously in immunocompetent C57BL/6 mice but not in immunodeficient NSG mice. Correspondingly, the frequency of total CD45+ tumor-infiltrating leukocytes was significantly increased in CCN4-KO tumors, with increased natural killer (NK) and effector CD8+ T cells and reduced myeloid-derived suppressor cells (MDSC). Additionally, the absence of tumor-derived CCN4 was associated with an impaired splenic generation of suppressive granulocytic MDSC. Among mechanisms linked to local immunosuppression, we found CCN4 directly suppressed antigen-induced IFN{gamma} release by CD8+ T cells, promoted glycolysis and consequent lactate release by melanoma cells, and enhanced tumor secretion of MDSC-attracting chemokines like CCL2 and CXCL1. Finally, CCN4-KO in B16F0 and YUMM1.7 melanoma cells complemented the anti-tumor effect of immune checkpoint blockade (ICB) therapy. Overall, our results suggest that CCN4 promotes tumor-induced immunosuppression and is a potential target for therapeutic combinations with ICB. Statement of SignificanceGiven emerging interest in understanding the interplay between functional plasticity and anti-tumor immunity, Cell Communication Network factor 4, a secreted matricellular protein linked to promoting metastasis in melanoma, also suppresses anti-tumor immunity.

cancer biology↗

bioRxiv2018

CCN4 shifts melanoma cells from a fragile proliferative state to a resilient metastatic state

While deregulated intracellular signaling initiates melanoma, intercellular crosstalk within the tumor microenvironment, often coordinated by soluble factors, is essential for melanoma progression and metastasis. One such secreted matricellular protein, cellular communication network factor 4 (CCN4), stimulates metastasis in other malignancies. Here, we report that CCN4 expression is associated progressively with reduced overall survival in patients with primary melanomas. To reveal the roles of CCN4 in melanoma progression, we used mouse melanoma models and knocked out Ccn4 using a homology-directed repair CRISPR/CAS9 system to generate pools of Ccn4-knockout cells. In vitro assays supported previous findings using clones generated using a double nickase-based CRISPR/CAS9 system that CCN4 promoted an epithelial - mesenchymal-like transition in melanoma cells and stimulated invasion and metastasis. We also found that, while Ccn4 knockout enhanced cell growth in optimal 2D culture conditions, the knockout suppressed certain cell survival signaling pathways and rendered cells less resistant to stress conditions. Tumor cell growth assays at sub-optimal conditions in vitro, quantitative analysis of tumor growth assays in vivo, and transcriptomics analysis of human melanoma cell lines suggested that CCN4 repressed cell growth and simultaneously enhanced cell survival. The collective role of CCN4 suggests a potential therapeutic target for limiting metastatic invasion in melanoma and a biomarker for metastatic potential.

cancer biology↗

bioRxiv2018

WNT1 Inducible Signaling Pathway Protein 1 (WISP1) Stimulates Melanoma Cell Invasion and Metastasis by Promoting Epithelial - Mesenchymal Transition (EMT)

Besides intrinsic changes, malignant cells release soluble signals to reshape their microenvironment. Among the signaling factors is WNT1 inducible signaling pathway protein 1 (WISP1), a secreted matricellular protein that is elevated in a variety of cancers including melanoma and is associated with reduced overall survival of patients diagnosed with primary melanoma. In this work, we found that WISP1 knockout both increased cell proliferation and repressed wound healing, migration and invasion of mouse and human melanoma cells in an ensemble of in vitro assays. In vivo metastasis assays showed that WISP1 knockout repressed tumor metastasis in both C57BL/6Ncrl and NOD-scid IL2Rgammanull (NSG) mice with B16F10 and YUMM1.7 melanoma cells. Mechanistically, B16F10 cells that invaded in a transwell assay possessed a gene expression signature similar to Epithelial - Mesenchymal Transition (EMT), including coincident repression of E-cadherin and induction of fibronectin and N-cadherin. Upon WISP1 knockout, these EMT signature genes went in opposite directions in both mouse and human cell lines and were rescued by media containing WISP1 or recombinant WISP1 protein. In vivo, metastasis repression by WISP1 knockout was reversed by the reintroduction of either WISP1 or SNAI1. A set of EMT gene activation and inhibition experiments using recombinant WISP1 or kinase inhibitors in B16F10 and YUMM1.7 cells suggested that WISP1 activates Akt and MAP kinase signaling pathways to shift melanoma cells from a proliferative to invasive phenotype. Collectively, the results supported a model that WISP1 within the tumor microenvironment stimulates melanoma invasion and metastasis by promoting an EMT-like process.

cancer biology↗

bioRxiv2017

Quantifying Spontaneous Metastasis In A Syngeneic Mouse Melanoma Model Using Real Time PCR

Modeling metastasis in vivo with animals is a priority for both revealing mechanisms of tumor dissemination and developing therapeutic methods. While conventional intravenous injection of tumor cells provides an efficient and consistent system for studying tumor cell extravasation and colonization, studying spontaneous metastasis derived from orthotopic tumor sites has the advantage of modeling more aspects of the metastatic cascade, but is challenging as it is difficult to detect small numbers of metastatic cells. In this work, we developed an approach for quantifying spontaneous metastasis in the syngeneic mouse B16 system using real time PCR. We first transduced B16 cells with lentivirus expressing firefly luciferase Luc2 gene for bioluminescence imaging. Next, we developed a real time quantitative PCR (qPCR) method for the detection of luciferase-expressing, metastatic tumor cells in mouse lungs and other organs. To illustrate the approach, we quantified lung metastasis in both spontaneous and experimental scenarios using B16F0 and B16F10 cells in C57BL/6Ncrl and NOD-Scid Gamma (NSG) mice. We tracked B16 melanoma metastasis with both bioluminescence imaging and qPCR, which were found to be self-consistent. Using this assay, we can quantitatively detect one Luc2 positive tumor cells out of 104 tissue cells, which corresponds to a metastatic burden of 1.8x104 metastatic cells per whole mouse lung. More importantly, the qPCR method was at least a factor of 10 more sensitive in detecting metastatic cell dissemination and should be combined with bioluminescence imaging as a high-resolution, end-point method for final metastatic cell quantitation. Given the rapid growth of primary tumors in many mouse models, assays with improved sensitivity can provide better insight into biological mechanisms that underpin tumor metastasis.

cancer biology↗