The interplay between tumor cells and the microenvironment has been recognized as one of the hallmarks of cancer biology. To assess the role of extracellular matrix (ECM) in the modulation of tissue homeostasis and tumorigenesis, we developed a protocol for the purification of tissue-derived ECM using mucosae from healthy human colon, perilesional area, and colorectal carcinoma (CRC). Matched specimens were collected from the left colon of patients undergoing CRC resection surgery. ECMs were obtained from tissues that were decellularized with hypotonic solutions containing ionic and nonionic detergents, hypertonic solution, and endonuclease in the absence of denaturing agents. Mucosae-derived ECMs maintained distribution and localization of proteins and glycoproteins typical of the original tissues, and showed different three-dimensional (3D) structures among normal versus perilesional and tumor-derived stroma. The three types of ECM differentially regulated the localization and organization of seeded monocytes and cancer cells that were located and organized as in the original tissue. Specifically, healthy, perilesional, and CRC-derived ECMs sustained differentiation and polarization of cancer epithelial cells. In addition, healthy, but not perilesional and CRC-derived ECM constrained invasion of cancer cells. All three ECMs sustained turnover between cell proliferation and death up to 40 days of culture, although each ECM showed different ability in supporting cell proliferation, with tumor > perilesional > healthy-derived ECMs. Healthy-, perilesional-and CRC-derived ECM differently modulated cell homeostasis, spreading in the stroma and turnover between proliferation and death, and equally supported differentiation and polarization of cancer epithelial cells, thus highlighting the contribution of different ECMs modulating some features of tissue homeostasis and tumorigenesis. Moreover, these ECMs provide competent scaffolds useful to assess efficacy of antitumor drugs in a 3D setting that more closely recapitulates the native microenvironment. Further, ECM-based scaffolds may also be beneficial for future studies seeking prognostic and diagnostic stromal markers and targets for antineoplastic drugs.

Cell-associated receptor for urokinase plasminogen activator (uPAR) is released as both full-length soluble uPAR (suPAR) and cleaved (c-suPAR) form that maintain ability to bind to integrins and other receptors, thus triggering and modulating cell signaling responses. Concerning HIV-1 infection, plasma levels of suPAR have been correlated with the severity of disease, levels of immune activation and ineffective immune recovery also in individuals receiving combination anti-retroviral therapy (cART). However, it is unknown whether and which suPAR forms might contribute to HIV-1 induced pathogenesis and to the related state of immune activation. In this regard, lymphoid organs represent an import site of chronic immune activation and virus persistence even in individuals receiving cART. Lymphoid organs of HIV-1+ individuals showed an enhanced number of follicular dendritic cells, macrophages and endothelial cells expressing the cell-associated uPAR in comparison to those of uninfected individuals. In order to investigate the potential role of suPAR forms in HIV-1 infection of secondary lymphoid organs, tonsil histocultures were established from HIV-1 seronegative individuals and infected ex vivo with CCR5- and CXCR4-dependent HIV-1 strains. The levels of suPAR and c-suPAR were significantly increased in HIV-infected tonsil histocultures supernatants in comparison to autologous uninfected histocultures. Supernatants from infected and uninfected cultures before and after immunodepletion of suPAR forms were incubated with the chronically infected promonocytic U1 cell line characterized by a state of proviral latency in unstimulated conditions. In the contest of HIV-conditioned supernatants we established that c-suPAR, but not suPAR, inhibited chemotaxis and induced virus expression in U1 cells. In conclusion, lymphoid organs are an important site of production and release of both suPAR and c-suPAR, this latter form being endowed with the capacity of inhibiting chemotaxis and inducing HIV-1 expression.