Rapid Setup of Tissue Microarray and Tiled Area Imaging on the Multiplexed Ion Beam Imaging Microscope using the Tile/SED/Array Interface.

Multiplexed ion beam imaging (MIBI) is a next-generation mass spectrometry-based microscopy technique that generates 40+ plex images of protein expression in histologic tissues, enabling detailed dissection of cellular phenotypes and histoarchitectural organization. A key bottleneck in operation occurs when users select the physical locations on the tissue for imaging. As the scale and complexity of MIBI experiments have increased, the manufacturer-provided interface and third-party tools have become increasingly unwieldy for imaging large tissue microarrays and tiled tissue areas. Thus, a web-based, interactive, what-you-see-is-what-you-get (WYSIWYG) graphical interface layer - the tile/SED/array Interface (TSAI) - was developed for users to set imaging locations using familiar and intuitive mouse gestures such as drag-and-drop, click-and-drag, and polygon drawing. Written according to web standards already built into modern web browsers, it requires no installation of external programs, extensions, or compilers. Of interest to the hundreds of current MIBI users, this interface dramatically simplifies and accelerates the setup of large, complex MIBI runs.

Venetoclax sensitivity in multiple myeloma is associated with B-cell gene expression.

Venetoclax is a highly potent, selective BCL2 inhibitor capable of inducing apoptosis in cells dependent on BCL2 for survival. Most myeloma is MCL1-dependent; however, a subset of myeloma enriched for translocation t(11;14) is codependent on BCL2 and thus sensitive to venetoclax. The biology underlying this heterogeneity remains poorly understood. We show that knockdown of cyclin D1 does not induce resistance to venetoclax, arguing against a direct role for cyclin D1 in venetoclax sensitivity. To identify other factors contributing to venetoclax response, we studied a panel of 31 myeloma cell lines and 25 patient samples tested for venetoclax sensitivity. In cell lines, we corroborated our previous observation that BIM binding to BCL2 correlates with venetoclax response and further showed that knockout of BIM results in decreased venetoclax sensitivity. RNA-sequencing analysis identified expression of B-cell genes as enriched in venetoclax-sensitive myeloma, although no single gene consistently delineated sensitive and resistant cells. However, a panel of cell surface makers correlated well with ex vivo prediction of venetoclax response in 21 patient samples and may serve as a biomarker independent of t(11;14). Assay for transposase-accessible chromatin sequencing of myeloma cell lines also identified an epigenetic program in venetoclax-sensitive cells that was more similar to B cells than that of venetoclax-resistant cells, as well as enrichment for basic leucine zipper domain-binding motifs such as BATF. Together, these data indicate that remnants of B-cell biology are associated with BCL2 dependency and point to novel biomarkers of venetoclax-sensitive myeloma independent of t(11;14).

Tuning Nanoparticle Interactions with Ovarian Cancer through Layer-by-Layer Modification of Surface Chemistry.

Nanoparticle surface chemistry is a fundamental engineering parameter that governs tumor-targeting activity. Electrostatic assembly generates controlled polyelectrolyte complexes through the process of adsorption and charge overcompensation utilizing synthetic polyions and natural biomacromolecules; it can yield films with distinctive hydration, charge, and presentation of functional groups. Here, we used electrostatic layer-by-layer (LbL) assembly to screen 10 different surface chemistries for their ability to preferentially target human ovarian cancer in vitro. Our screen identified that poly-l-aspartate, poly-l-glutamate, and hyaluronate-coated LbL nanoparticles have striking specificity for ovarian cancer, while sulfated poly(ß-cyclodextrin) nanoparticles target noncancerous stromal cells. We validated top candidates for tumor-homing ability with a murine model of metastatic disease and with patient-derived ovarian cancer spheroids. Nanoparticle surface chemistry also influenced subcellular trafficking, indicating strategies to target the cell membrane, caveolae, and perinuclear vesicles. Our results confirm LbL is a powerful tool to systematically engineer nanoparticles and achieve specific targeting.

RNA-Peptide nanoplexes drug DNA damage pathways in high-grade serous ovarian tumors.

DNA damaging chemotherapy is a cornerstone of current front-line treatments for advanced ovarian cancer (OC). Despite the fact that a majority of these patients initially respond to therapy, most will relapse with chemo-resistant disease; therefore, adjuvant treatments that synergize with DNA-damaging chemotherapy could improve treatment outcomes and survival in patients with this deadly disease. Here, we report the development of a nanoscale peptide-nucleic acid complex that facilitates tumor-specific RNA interference therapy to chemosensitize advanced ovarian tumors to frontline platinum/taxane therapy. We found that the nanoplex-mediated silencing of the protein kinase, MK2, profoundly sensitized mouse models of high-grade serous OC to cytotoxic chemotherapy by blocking p38/MK2-dependent cell cycle checkpoint maintenance. Combined RNAi therapy improved overall survival by 37% compared with platinum/taxane chemotherapy alone and decreased metastatic spread to the lungs without observable toxic side effects. These findings suggest (a) that peptide nanoplexes can serve as safe and effective delivery vectors for siRNA and (b) that combined inhibition of MK2 could improve treatment outcomes in patients currently receiving frontline chemotherapy for advanced OC.