We report a facile and scalable method to fabricate biomimetic giant liposomes by using a cellulose paper-based materials platform. Termed PAPYRUS for Paper-Abetted liPid hYdRation in aqUeous Solutions, the method is general and can produce liposomes in various aqueous media and at elevated temperatures. Encapsulation of macromolecules and production of liposomes with membranes of complex compositions is straightforward. The ease of manipulation of paper makes practical massive parallelization and scale-up of the fabrication of giant liposomes, demonstrating for the first time the surprising usefulness of paper as a platform for macromolecular self-assembly.

This paper reports the development of Metal-amplified Density Assays, or MADAs - a method of conducting quantitative or multiplexed assays, including immunoassays, by using Magnetic Levitation (MagLev) to measure metal-amplified changes in the density of beads labeled with biomolecules. The binding of target analytes (i.e. proteins, antibodies, antigens) to complementary ligands immobilized on the surface of the beads, followed by a chemical amplification of the binding in a form that results in a change in the density of the beads (achieved by using gold nanoparticle-labeled biomolecules, and electroless deposition of gold or silver), translates analyte binding events into changes in density measureable using MagLev. A minimal model based on diffusion-limited growth of hemispherical nuclei on a surface reproduces the dynamics of the assay. A MADA - when performed with antigens and antibodies - is called a Density-Linked Immunosorbent Assay, or DeLISA. Two immunoassays provided a proof of principle: a competitive quantification of the concentration of neomycin in whole milk, and a multiplexed detection of antibodies against Hepatitis C virus NS3 protein and syphilis T. pallidum p47 protein in serum. MADAs, including DeLISAs, require, besides the requisite biomolecules and amplification reagents, minimal specialized equipment (two permanent magnets, a ruler or a capillary with calibrated length markings) and no electrical power to obtain a quantitative readout of analyte concentration. With further development, the method may be useful in resource-limited or point-of-care settings.

PIN1 is a phosphorylation-directed prolyl isomerase that alters the conformation and, therefore, the function of many proteins. Due to its role in activation and stabilization of many oncogenes, we hypothesized that targeting PIN1 in pancreatic ductal adenocarcinoma (PDA) would slow tumor growth. We tested this hypothesis in vitro and in vivo with PIN1 inhibitors and/or genetic model systems. Pancreatic cancer cell lines knocked down for PIN1 or treated with PIN1 inhibitors showed decreased proliferation, invasion, and anchorage independent growth compared to control lines. Consistent with these in vitro results, treatment of pancreatic cancer xenografts or genetically engineered p48-Cre; LSL-KrasG12D; p53R172H (KPC) mice with PIN1 inhibitors decreased tumor growth and extended overall survival. Similar results were seen in KPC mice that were crossed into a full body PIN1 knockout (PIN1−/−). Further analysis of KPC PIN1−/− tumors revealed not only reduced size of pancreatic tumors, but also decreased alpha-SMA expression and decreased ECM deposition in the stroma surrounding the tumors. PDA is characterized by a dense, desmoplastic tumor stroma that contributes to tumor growth, metastasis, and therapeutic resistance. Pancreatic stellate cells (PSCs) that are activated in the tumor microenvironment play a major role in the deposition of ECM and secrete growth factors to support tumor cell proliferation and survival. To interrogate a direct role for PIN1 in the stroma, we first orthotopically injected a KPC cell line into syngeneic PIN1+/+ or PIN1−/− mice and found dramatic reduction of tumor cell growth in PIN1−/− hosts. Next, we analyzed PSCs in vitro and found that loss of PIN1 reduces their proliferation and alters their secretion of paracrine factors that support oncogenic phenotypes. For example, PSCs with loss of PIN1 have reduced expression of HGF and increased expression of SPINT1 and SPINT2, inhibitors of HGF activation. Conditioned media from control PSCs, but not from PSCs lacking PIN1 expression, activates the MET receptor on cancer cell lines, resulting in altered cancer cell phenotypes. In addition, we show that loss of PIN1 in PSCs inhibits TGF-beta induced stellate cells activation into a myofibroblast phenotype. Single cell ATAC-seq analysis demonstrated that a subset of TGF-beta responsive chromatin changes are impaired in the absence of PIN1. Our ongoing work utilizes 2D co-cultures, heterotypic 3D bioprinted tissues, and in vivo mouse models to interrogate the mechanisms by which fibroblast phenotypes and the tumor-stromal crosstalk is impacted by PIN1. Citation Format: Ellen M. Langer, Isabel A. English, Kayleigh M. Kresse, Kevin MacPherson, Brittany L. Allen-Petersen, Colin J. Daniel, Andrew Adey, Rosalie C. Sears. The prolyl isomerase PIN1 plays a critical role in fibroblast plasticity to impact pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr LT012.

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