Dubreuil, J. | Search bioRxiv

bioRxiv2025

Human mammary 3D spheroid models uncover the role of filopodia in breaching the basement membrane to facilitate invasion

Basement membranes (BM) are thin, nanoporous sheets of specialized extracellular matrix (ECM) that line epithelial tissues. They are dynamic structures that serve multiple key functions, as evidenced by numerous diseases, including cancer progression, that are associated with their alterations. Our understanding of the BM and its communication with adjoining epithelial cells remains highly fragmented due to the BMs complex molecular architecture, the lack of molecular tools, limitations in utilizing high-resolution imaging techniques to BMs assembled on tissues, and the difficulty of assessing their functional contributions in vivo. Here, by combining multiple -omics analyses and advanced microscopy methodologies, we characterized the BM from two normal human mammary epithelial cell lines, MCF10 and HMLE, grown as spheroids in 3D matrices. Our findings indicate that the spheroids autonomously assemble a BM exhibiting all the molecular, structural, and biophysical characteristics of physiological BM. Using these minimalist model systems, we show for the first time that the laminins, perlecan, and the hemidesmosomes are all arranged along a shared porous lattice defined by the collagen IV molecular network. Next, we demonstrate that the invasion-promoting PSD4/EFA6B knockout, found in patients with breast cancer, decreases the expression of BM components and their assembly on the spheroid surface. We then show that invasive spheroids develop enlarged pores in the BM via filopodia-like plasma membrane extensions, which further expand in a protease-dependent manner, thereby facilitating the passage of invasive cells. Significance StatementThe basement membrane (BM) directs epithelial tissue architecture and behavior. How tumor cells breach this barrier during invasion remains poorly understood. Using minimalist 3D spheroid models mimicking physiological BM assembly, we reveal a novel infiltration mechanism. Filopodia-like protrusions perforate and widen BM pores. This facilitates cell dissemination through sequential protease-independent and -dependent steps.

cell biology↗

bioRxiv2020

Marine reserve benefits and recreational fishing yields: the winners and the losers

Marine reserves constitute effective tools for preserving fish stocks and associated human benefits. However, not all reserves perform equally, and predicting the response of marine communities to management actions in the long run is challenging. Our decadal-scale survey of recreational fishing yields at Frances 45-year old Cerbere-Banyuls marine reserve indicated significant protection benefits, with 40-50% higher fishing yields per unit effort in the partial-protection zone of the reserve (where fishing is permitted but at a lower level) than in surrounding non-reserve areas. Over the period 2005-2014, catch per unit effort (CPUE) showed a similar pattern of decline inside and outside the reserve while weight per unit effort (WPUE) increased by 131% inside and decreased by 60% outside. Different CPUE and WPUE trajectories among fish families indicated changing catch assemblages, with yields increasing for the family most valued by fisheries, Sparidae (the ecological winners). However, reserve benefits were restricted to off-shore fishermen (the social winners), as on-shore yields were [~]4 times lower and declining, even inside the reserve. Our study illustrates how surveys of recreational fishing yields can help evaluate the effectiveness of marine protected areas for key social and ecological protagonists. We show that, more than four decades after its establishment, fishing efficiencies at the historical Cerbere-Banyuls marine reserve are still changing, but benefits in terms of catch abundance, weight, and composition remain predominantly restricted to off-shore fishermen. Further regulations appear necessary to guarantee that conservation strategies equitably benefit societal groups.

ecology↗