Rett syndrome (RTT) is a genetic disorder resulting from a loss-of-function mutation in one copy of the X-linked gene methyl-CpG-binding protein 2 (). Typical RTT patients are females and, due to random X chromosome inactivation (XCI), ∼50% of cells express mutant MECP2 and the other ∼50% express wild-type MECP2. Cells expressing mutant MECP2 retain a wild-type copy of MECP2 on the inactive X chromosome (Xi), the reactivation of which represents a potential therapeutic approach for RTT. Previous studies have demonstrated reactivation of Xi-linked in cultured cells by biological or pharmacological inhibition of factors that promote XCI (called "XCI factors" or "XCIFs"). Whether XCIF inhibitors in living animals can reactivate Xi-linked in cerebral cortical neurons, the cell type most therapeutically relevant to RTT, remains to be determined. Here, we show that pharmacological inhibitors targeting XCIFs in the PI3K/AKT and bone morphogenetic protein signaling pathways reactivate Xi-linked in cultured mouse fibroblasts and human induced pluripotent stem cell-derived postmitotic RTT neurons. Notably, reactivation of Xi-linked corrects characteristic defects of human RTT neurons including reduced soma size and branch points. Most importantly, we show that intracerebroventricular injection of the XCIF inhibitors reactivates Xi-linked in cerebral cortical neurons of adult living mice. In support of these pharmacological results, we also demonstrate genetic reactivation of Xi-linked in cerebral cortical neurons of living mice bearing a homozygous XCIF deletion. Collectively, our results further establish the feasibility of pharmacological reactivation of Xi-linked as a therapeutic approach for RTT.

Despite extensive efforts to characterize the transcriptional landscape of pancreatic ductal adenocarcinoma (PDA), reproducible assessment of subtypes with actionable dependencies remains challenging. Systematic, network-based analysis of regulatory protein activity stratified PDA tumours into novel functional subtypes that were highly conserved across multiple cohorts, including at the single cell level and in laser capture microdissected (LCM) samples. Identified subtypes were characterized by activation of master regulator proteins representing either gastrointestinal lineage markers or transcriptional effectors of morphogen pathways. Single cell analysis confirmed the existence of Lineage and Morphogenic states but also revealed a dominant population of more differentiated Oncogenic Precursor (OP) cells , present in all sampled patients, yet not apparent from bulk tumor analysis. Master regulators were validated by pooled, CRISPR/Cas9 screens, demonstrating both subtype-specific and universal dependencies. Conversely, ectopic expression of Lineage MRs, such as OVOL2, was sufficient to reprogram Morphogenic cells, thus providing a roadmap for the future targeting of patient-specific dependencies in PDA.

Compounds that recognize and strongly bind to molecular targets are one of the cornerstones of modern pharmaceutics. Work has been ongoing for the past 25 years on the therapeutic use of aptamers, nucleic acid molecules, whose three-dimensional structure is the result of interactions between complementary base pairs. The aptamers selection methods allow the oligonucleotides which bind the molecular target in its native environment to be quickly isolated from a large library of random oligonucleotides. The possibilities presented for aptamers in the field of targeted therapy require the application of effective carriers to counter the renal clearance effect and/or functional cargo to exert therapeutic action if the aptamer is only used as a targeting moiety. Lately, a material gaining ground in biomedical research is iron oxide particles, which exhibit a superparamagnetic characteristic at nanoscale levels. This allows the iron oxide nanoparticles to convert external magnetic energy into heat, a mechanism known as hyperthermy, and efficiently supports conventional oncological treatment. In this study, we describe an experimentally confirmed functional model of targeted anticancer hyperthermia therapy. Using the systematic evolution of ligands by exponential enrichment technique, we selected a DNA aptamer that specifically binds to the extracellular domain of recombinant fibroblast growth factor receptor type-1 (FGFR1) with a nanomolar dissociation constant. The chosen target plays an important role in many crucial cellular processes and is also considered a candidate protein that is involved in tumor initiation, survival and progression. Next, we combined the selected aptamer with iron oxide nanoparticles to produce aptamer superparamagnetic conjugates (ASCs). Finally, we found that targeted ASCs selectively destroy FGFR1-overexpressing human osteosarcoma cells U2OS upon magnetic field irradiation.

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The sparse vascularity of Pancreatic Ductal Adenocarcinoma (PDAC) presents a mystery: what prevents this aggressive malignancy from undergoing neoangiogenesis to counteract hypoxia and better support growth? An incidental finding from prior work on paracrine communication between malignant PDAC cells and fibroblasts revealed that inhibition of the Hedgehog (HH) pathway partially relieved angiosuppression, increasing tumor vascularity through unknown mechanisms. Initial efforts to study this phenotype were hindered by difficulties replicating the complex interactions of multiple cell typesin vitro. Here we identify a cascade of paracrine signals between multiple cell types that act sequentially to suppress angiogenesis in PDAC. Malignant epithelial cells promote HH signaling in fibroblasts, leading to inhibition of WNT signaling in fibroblasts and epithelial cells, thereby limiting VEGFR2-dependent activation of endothelial hypersprouting. This cascade was elucidated using human and murine PDAC explant models, which effectively retain the complex cellular interactions of native tumor tissues.