Prostate cancer antigen 3 (PCA3) is the most specific prostate cancer biomarker but its function remains unknown. Here we identify PRUNE2, a target protein-coding gene variant, which harbors the PCA3 locus, thereby classifying PCA3 as an antisense intronic long noncoding (lnc)RNA. We show that PCA3 controls PRUNE2 levels via a unique regulatory mechanism involving formation of a PRUNE2/PCA3 double-stranded RNA that undergoes adenosine deaminase acting on RNA (ADAR)-dependent adenosine-to-inosine RNA editing. PRUNE2 expression or silencing in prostate cancer cells decreased and increased cell proliferation, respectively. Moreover, PRUNE2 and PCA3 elicited opposite effects on tumor growth in immunodeficient tumor-bearing mice. Coregulation and RNA editing of PRUNE2 and PCA3 were confirmed in human prostate cancer specimens, supporting the medical relevance of our findings. These results establish PCA3 as a dominant-negative oncogene and PRUNE2 as an unrecognized tumor suppressor gene in human prostate cancer, and their regulatory axis represents a unique molecular target for diagnostic and therapeutic intervention.S everal lines of evidence demonstrate that long noncoding RNAs (lncRNAs) are functional in carcinogenesis through regulatory mechanisms such as promoter looping, alternative splicing, antisense gene silencing, transcriptional regulation, and DNA repair, thus potentially serving as tumor markers. A few lncRNA species have emerged as potential prostate cancer biomarkers such as prostate cancer gene expression marker-1 (PCGEM1) and prostate cancer noncoding RNA1 (PRNCR1), which enhance androgen receptor (AR)-dependent gene activation, and prostate cancer-associated ncRNA transcript-1 (PCAT1), which silences BRCA2 via posttranscriptional homologous recombination (1). Notably, the most specific biomarker in human prostate cancer identified to date is an lncRNA, prostate cancer antigen 3 (PCA3, also known as PCA3 DD3 or DD3 PCA3 ), which is up-regulated in human prostate cancer (2). Since its discovery more than 15 y ago, PCA3 has been extensively investigated (3) and has been approved for clinical applications to aid the diagnosis of prostate cancer in both the European Union and the United States. Paradoxically-despite its striking clinical specificity-the inherent cellular role of the lncRNA PCA3 in human prostate cancer, if any, remains completely unknown (1). Here we report a unique biological function for PCA3. Within a single functional genetic unit, we show that PCA3 is an antisense intronic lncRNA that down-regulates an as yet unrecognized tumor suppressor gene, a human homolog of the Drosophila prune gene, PRUNE2, through a process that involves RNA editing mediated by a supramolecular complex containing adenosine deaminase acting on RNA (ADAR) family members. We propose a working model in which PCA3 acts as a dominant-negative oncogene in prostate cancer and show consistent results in therapeutic preclinical models and in patient-derived human samples. Therefore, the molecular interaction of PRUNE2...

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Phage display screening allows the study of functional protein–protein interactions at the cell surface, but investigating intracellular organelles remains a challenge. Here we introduce internalizing-phage libraries to identify clones that enter mammalian cells through a receptor-independent mechanism and target-specific organelles as a tool to select ligand peptides and identify their intracellular receptors. We demonstrate that penetratin, an antennapedia-derived peptide, can be displayed on the phage envelope and mediate receptor-independent uptake of internalizing phage into cells. We also show that an internalizing-phage construct displaying an established mitochondria-specific localization signal targets mitochondria, and that an internalizing-phage random peptide library selects for peptide motifs that localize to different intracellular compartments. As a proof-of-concept, we demonstrate that one such peptide, if chemically fused to penetratin, is internalized receptor-independently, localizes to mitochondria, and promotes cell death. This combinatorial platform technology has potential applications in cell biology and drug development.

A major challenge of targeted molecular imaging and drug delivery in cancer is establishing a functional combination of ligand-directed cargo with a triggered release system. Here we develop a hydrogelbased nanotechnology platform that integrates tumor targeting, photon-to-heat conversion, and triggered drug delivery within a single nanostructure to enable multimodal imaging and controlled release of therapeutic cargo. In proof-of-concept experiments, we show a broad range of ligand peptide-based applications with phage particles, heat-sensitive liposomes, or mesoporous silica nanoparticles that self-assemble into a hydrogel for tumor-targeted drug delivery. Because nanoparticles pack densely within the nanocarrier, their surface plasmon resonance shifts to near-infrared, thereby enabling a laser-mediated photothermal mechanism of cargo release. We demonstrate both noninvasive imaging and targeted drug delivery in preclinical mouse models of breast and prostate cancer. Finally, we applied mathematical modeling to predict and confirm tumor targeting and drug delivery. These results are meaningful steps toward the design and initial translation of an enabling nanotechnology platform with potential for broad clinical applications. A long-term goal in contemporary cancer nanomedicine has been to design and generate drug delivery systems that improve the narrow therapeutic window associated with conventional chemotherapeutics (1, 2). Conceptually, several nanotechnologybased entity candidates, including protocells (3), biosynthetic nanoparticles (NPs), viruses, and liposome-based nanoparticles, could be targeted for active delivery through a defined cell surface ligand receptor system and/or physically triggered for finely tuned cargo release (2, 4, 5).Numerous efforts have been made to functionalize NPs by combining them with antibodies, aptamers, peptides, vitamins, or carbohydrates (6-8), but the majority of studies involve untargeted nanoplatforms (4, 9). In practice, targeting NPs is far from trivial, and ongoing challenges include synthesis and purification, selection of an appropriate ligand receptor, and specific composition for NP conjugation. Even the conjugation reaction itself may alter the binding of the tumor-targeting moiety to its receptor through conformational changes, steric freedom restriction, or orientation distortion (10, 11). Unfortunately, the SignificanceThe main goal in the emerging field of cancer nanomedicine is to generate, standardize, and produce multifunctional carriers designed to improve the response of drugs against tumors. Here we report the design, development, and preclinical validation of a ligand-directed bioinorganic platform that integrates tumor targeting, receptor-mediated cell internalization, photon-to-heat conversion, and drug delivery. This enabling hydrogel-based technology can accommodate a broad variety of ligands, nanoparticles, and payloads. We show experimental proof-of-concept in mouse models of breast and prostate cancer with molecular imaging and marked reduct...

Idecabtagene vicleucel (ide-cel) was FDA approved in March 2021 for the treatment of relapsed/refractory multiple myeloma (RRMM) after 4 lines of therapy. On the KarMMa trial, grade ≥3 cytopenias and infections were common. We sought to characterize cytopenias and infections within 100 days after ide-cel in the standard of care (SOC) setting. This multi-center retrospective study included 52 patients who received SOC ide-cel; 47 reached day 90 follow-up. Data was censored at day 100. Grade ≥3 cytopenia was present among 65% of patients at day 30 and 40% of patients at day 90. Granulocyte colony stimulating factor (G-CSF) was administered to 88%, packed red blood cell (pRBC) transfusions to 63%, platelet transfusions to 42%, thrombopoietin (TPO) agonists to 21%, intravenous immunoglobulin (IVIG) to 13%, and CD34+ stem cell boosts to 8%. At day 100, 19% and 13% of patients had ongoing use of TPO agonists and G-CSF, respectively. Infections occurred in 54% of patients and were grade ≥3 in 23%. Earlier infections in the first 30 days were typically bacterial (68%) and severe (50%). Later infections between days 31 - 100 were 50% bacterial and 42% viral; only 13% were grade ≥3. On univariate analysis, high pre-CAR-T marrow myeloma burden (>/= 50%), circulating plasma cells at pre-lymphodepletion (LD), and grade ≥3 anemia at pre-LD were associated with grade ≥3 cytopenia at both days 30 and 90. Longer time from last bridging treatment to LD was the only significant risk factor for infection.