Cancer-associated fibroblasts expressing fibroblast activation protein and podoplanin in non-small cell lung cancer predict poor clinical outcome

Secondary lymphoid tissues develop specialized stromal networks to facilitate immune cell communication and efficient activation of adaptive immunity. This stromal architecture is robust, maintaining topology throughout extensive remodelling and tissue expansion in response to immune challenge. We have previously reported that cytoskeletal mechanics of the fibroblastic reticular cell (FRC) networks determine tissue tension, and that increased tension initiates stromal proliferation required for lymph node growth. However, it is not known how FRCs mechanistically reshape the stromal network to preserve integrity through the early phases of inflammation. Here, we find a signalling mechanism which coordinates reduced FRC contractility and induction of stromal cell protrusions. RhoA/C GTPase activity is blocked in FRCs to inhibit actomyosin contractility upon contact with CLEC-2+ dendritic cells (DCs) and binding to podoplanin+ stroma. We now find that an additional Rho GTPase target, the PKC family kinase PKN2, regulates activity of myristoylated alanine-rich protein kinase C-substrate (MARCKS). FRCs use MARCKS to generate protrusions in response to DC contact. We tested this mechanism in vivo and found that PKN2 knock-out lymph nodes are unable to regulate MARCKS and show severely disrupted stromal architecture during lymph node expansion. We now present a mechanism of stromal/immune cell crosstalk which actively induces FRC protrusions – an essential component of lymph node remodelling – to maintain tissue integrity during an adaptive immune response.

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A Fibroblast-Derived Secretome Stimulates the Growth and Invasiveness of 3D Plexiform Neurofibroma Spheroids

Ji,

Schwenkel,

Mattingly

et al. 2024

Cancers

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Plexiform neurofibromas (PNs) occur in about a half of neurofibromatosis type 1 (NF1) patients and have garnered significant research attention due to their capacity for growth and potential for malignant transformation. NF1 plexiform neurofibroma (pNF1) is a complex tumor composed of Schwann cell-derived tumor cells (Nf1−/−) and the tumor microenvironment (TME). Although it has been widely demonstrated that the TME is involved in the formation of neurofibromas, little is known about the effects of the TME on the subsequent progression of human pNF1. Elucidating the molecular interactions between tumor cells and the TME may provide new therapeutic targets to reduce the progression of pNF1. In the present study, we focused on the contributions of fibroblasts, the most abundant cell types in the TME, to the growth of pNF1. To simulate the TME, we used a three-dimensional (3D) coculture model of immortalized pNF1 tumor cells (Nf1−/−) and primary fibroblasts (Nf1+/−) derived from pNF1 patients. We performed live-cell imaging of 3D/4D (3D in real-time) cultures through confocal microscopy followed by 3D quantitative analyses using advanced imaging software. The growth of pNF1 spheroids in 3D cocultures with fibroblasts was significantly greater than that of pNF1 spheroids in 3D monocultures. An increase in the growth of pNF1 spheroids also occurred when they were cultured with conditioned media (CM) from fibroblasts. Moreover, fibroblast-derived CM increased the invasive outgrowth and further local invasion of pNF1 spheroids. Interestingly, when small extracellular vesicles (sEVs) were depleted from the fibroblast-derived CM, the stimulation of the growth of pNF1 spheroids was lost. Our results suggest that fibroblast-derived sEVs are a therapeutic target for reducing the growth of pNF1.

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Cancer-associated fibroblasts expressing fibroblast activation protein and podoplanin in non-small cell lung cancer predict poor clinical outcome

Cited by 3 publications

References 54 publications

IL-17A-induced cancer-associated fibroblasts releases CXCL12 to promote lung adenocarcinoma progression via Wnt/β-Catenin signaling pathway

IL-17A-induced cancer-associated fibroblasts releases CXCL12 to promote lung adenocarcinoma progression via Wnt/β-Catenin signaling pathway

PKN2 signalling induces stromal cell protrusions to preserve lymph node structural integrity

A Fibroblast-Derived Secretome Stimulates the Growth and Invasiveness of 3D Plexiform Neurofibroma Spheroids

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