The majority of cancers arise from malignant epithelial cells. We report the design of synthetic oligonucleotides (aptamers) that are only internalized by epithelial cancer cells and can be precisely activated by light to kill such cells. Specifically, phototoxic DNA aptamers were selected to bind to unique short O-glycan-peptide signatures on the surface of breast, colon, lung, ovarian and pancreatic cancer cells. These surface antigens are not present on normal epithelial cells but are internalized and routed through endosomal and Golgi compartments by cancer cells, thus providing a focused mechanism for their intracellular delivery. When modified at their 5′ end with the photodynamic therapy agent chlorin e6 and delivered to epithelial cancer cells, these aptamers exhibited a remarkable enhancement (>500-fold increase) in toxicity upon light activation, compared to the drug alone and were not cytotoxic towards cell types lacking such O-glycan-peptide markers. Our findings suggest that these synthetic oligonucleotide aptamers can serve as delivery vehicles in precisely routing cytotoxic cargoes to and into epithelial cancer cells.

BackgroundThymus transplantation is a promising strategy for the treatment of athymic complete DiGeorge syndrome (cDGS).MethodsTwelve patients with cDGS underwent transplantation with allogeneic cultured thymus.ObjectiveWe sought to confirm and extend the results previously obtained in a single center.ResultsTwo patients died of pre-existing viral infections without having thymopoiesis, and 1 late death occurred from autoimmune thrombocytopenia. One infant had septic shock shortly after transplantation, resulting in graft loss and the need for a second transplant. Evidence of thymopoiesis developed from 5 to 6 months after transplantation in 10 patients. Median circulating naive CD4 counts were 44 × 106/L (range, 11-440 × 106/L) and 200 × 106/L (range, 5-310 × 106/L) at 12 and 24 months after transplantation and T-cell receptor excision circles were 2,238/106 T cells (range, 320-8,807/106 T cells) and 4,184/106 T cells (range, 1,582-24,596/106 T cells). Counts did not usually reach normal levels for age, but patients were able to clear pre-existing infections and those acquired later. At a median of 49 months (range, 22-80 months), 8 have ceased prophylactic antimicrobials, and 5 have ceased immunoglobulin replacement. Histologic confirmation of thymopoiesis was seen in 7 of 11 patients undergoing biopsy of transplanted tissue, including 5 showing full maturation through to the terminal stage of Hassall body formation. Autoimmune regulator expression was also demonstrated. Autoimmune complications were seen in 7 of 12 patients. In 2 patients early transient autoimmune hemolysis settled after treatment and did not recur. The other 5 experienced ongoing autoimmune problems, including thyroiditis (3), hemolysis (1), thrombocytopenia (4), and neutropenia (1).ConclusionsThis study confirms the previous reports that thymus transplantation can reconstitute T cells in patients with cDGS but with frequent autoimmune complications in survivors.

In the Chx10-null ocular retardation (or J ) mouse, retinal progenitor cell (RPC) proliferation is impaired, and bipolar neurons, a late born cell type, fail to differentiate. It is unclear whether Chx10 is required to maintain proliferation throughout retinogenesis or whether the bipolar cell defect is an indirect effect of growth arrest. We show that Chx10 is dispensable for late-stage RPC proliferation but is essential to promote bipolar cell genesis in place of rods. Ectopic Chx10 expression drove bipolar instead of rod cell differentiation without affecting division. Converting Chx10 to an activator impaired bipolar cell differentiation, implying that repression is important for Chx10 activity. In the Chx10 null or J retina, only a small fraction of cells expressing mutated Chx10 mRNA were rods, but this fraction increased after p27 Kip1 inactivation, which partially rescues proliferation. Most significantly, acute Chx10 knockdown in the postnatal retina promoted rods in place of bipolar neurons without affecting division. Thus, Chx10 directly controls bipolar cell genesis by inhibiting rod differentiation independent of its temporally limited early effect on RPC proliferation.CVC domain ͉ homeobox ͉ homeodomain ͉ short-hairpin RNA

The poor prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is partially attributed to the invasive and metastatic behavior of this disease. Laminin subunit beta-3 (LAMB3) encodes one of the three subunits of LM-332, an extracellular matrix protein secreted by cultured human keratinocytes. In addition, LAMB3 is involved in the invasive and metastatic abilities of some types of cancer, including colon, pancreas, lung, cervix, stomach, and prostate cancer, but the role and mechanism of LAMB3 in PDAC have not been previously determined. Herein, we tentatively investigated the role of LAMB3 in the malignant biological behavior of PDAC. In this study, we demonstrated that LAMB3 is upregulated in PDAC. Inhibition of LAMB3 abrogated the tumorigenic outcomes of PI3K/Akt signaling pathway activation, including those involving cell cycle arrest, cell apoptosis, proliferation, invasion and migration in vitro, and tumor growth and liver metastasis in vivo. Our results showed that LAMB3 could mediate cell cycle arrest and apoptosis in PDAC cells and alter the proliferative, invasive, and metastatic behaviors of PDAC by regulating the PI3K/Akt signaling pathway. LAMB3 may be a novel therapeutic target for the treatment of PDAC in the future.

Poly(ADP-ribosyl)ation by poly(ADP-ribose) polymerases regulates the interaction of many DNA damage and repair factors with sites of DNA strand lesions. The interaction of these factors with poly (ADP-ribose) (PAR) is mediated by specific domains, including the recently identified PAR-binding zinc finger (PBZ) domain. However, the mechanism governing these interactions is unclear. To better understand the PBZ-PAR interaction, we performed a detailed examination of the representative PBZ-containing protein involved in the DNA damage response, aprataxin polynucleotide-kinase-like factor (APLF), which possesses two tandem PBZ domains. Here we present structural and biochemical studies that identify Y381/Y386 and Y423/Y428 residues in the conserved C(M/P)Y and CYR motifs within each APLF PBZ domain that are critical for the interaction with the adenine ring of ADP-ribose. Basic residues (R387 and R429 in the first and second PBZ domains, respectively) coordinate additional interactions with the phosphate backbone of ADP-ribose, suggesting that APLF binds to multiple ADP-ribose residues along PAR polymers. These C(M/P)Y and CYR motifs form a basic/hydrophobic pocket within a variant zinc finger structure and are required for APLF recruitment to sites of DNA damage in vivo.DNA damage signaling | high affinity T he DNA damage response (DDR) and maintenance of chromosomal stability is regulated in part by posttranslational modifications, including poly(ADP-ribosyl)ation by poly(ADPribose) polymerases (PARPs), which direct the recruitment of proteins involved in the signaling and repair of DNA damage. In addition, PARP enzymes are important regulators of chromatin remodeling, apoptosis, and transcription (1). In the early response to DNA damage, PARP1 is the predominant PARP activated by DNA strand lesions and catalyzes the attachment of multiple ADP-ribose (ADPr) units from nicotinamide adenine dinucleotide (NAD þ ) onto target proteins, including PARP1 itself (2). Poly(ADP-ribose) (PAR) accumulated at DNA breaks is subsequently metabolized to ADPr by PAR glycohydrolase (3). To date, PAR-binding motifs have been described in some macrodomains, which also bind to ADPr (4, 5), in a basic residue-rich motif interspersed with hydrophobic amino acids (6), and in the more recently described PAR-binding zinc finger (PBZ) domains (7). PBZ domains, present in proteins either as single or two tandem motifs, are limited to multicellular eukaryotes, and the majority of PBZ-containing proteins have putative roles in PAR metabolism, DNA repair, or DNA damage signaling (7-9).APLF (aprataxin polynucleotide kinase (PNK)-like factor, also known as PALF and Xip1) is a newly identified protein involved in the DDR possessing a forkhead-associated (FHA) domain and two tandem PBZ motifs (7-11) (Fig. 1A). APLF was originally identified based on the similarity of its FHA domain to those of PNK and aprataxin (12), which share functional similarities and direct FHA-and phosphothreonine-dependent interactions with the DNA repair proteins XRCC1 and...

Background:Germline mutations of the BRCA tumour suppressors have been associated with increased risk of pancreatic cancer. Clinical evidence suggests that these patients may be more sensitive to treatment with cisplatin. As the frequency of germline BRCA mutations is low, definitive experimental data to support the clinical observations are still missing.Methods:We tested gemcitabine and cisplatin sensitivity of four BRCA1 and BRCA2 mutant and three BRCA1 and BRCA2 wild-type (WT) patient-derived pancreatic cancer xenografts.Results:We observed treatment sensitivity to gemcitabine and cisplatin in the BRCA WT and mutant models. The BRCA1 and BRCA2 mutant xenografts were significantly more sensitive to cisplatin although these models also showed sensitivity to gemcitabine. The BRCA1 and BRCA2 WT models showed sensitivity to gemcitabine but not cisplatin. Treatment sensitivity in the xenograft models closely resembled treatment response in the corresponding patients.Discussion:We have characterised a panel of xenografts derived from pancreatic cancer patients carrying germline BRCA mutations, and shown that their genetic features resemble the patient donor. Our results support further clinical testing of treatment regimens combining gemcitabine and platinum drugs in this patient population, as well as preclinical research aiming to identify mechanisms of cisplatin resistance in BRCA mutant pancreatic cancers.

Automated flow cytometry (FC) data analysis tools for cell population identification and characterization are increasingly being used in academic, biotechnology, pharmaceutical, and clinical laboratories. The development of these computational methods is designed to overcome reproducibility and process bottleneck issues in manual gating, however, the take‐up of these tools remains (anecdotally) low. Here, we performed a comprehensive literature survey of state‐of‐the‐art computational tools typically published by research, clinical, and biomanufacturing laboratories for automated FC data analysis and identified popular tools based on literature citation counts. Dimensionality reduction methods ranked highly, such as generic t‐distributed stochastic neighbor embedding (t‐SNE) and its initial Matlab‐based implementation for cytometry data viSNE. Software with graphical user interfaces also ranked highly, including PhenoGraph, SPADE1, FlowSOM, and Citrus, with unsupervised learning methods outnumbering supervised learning methods, and algorithm type popularity spread across K‐Means, hierarchical, density‐based, model‐based, and other classes of clustering algorithms. Additionally, to illustrate the actual use typically within clinical spaces alongside frequent citations, a survey issued by UK NEQAS Leucocyte Immunophenotyping to identify software usage trends among clinical laboratories was completed. The survey revealed 53% of laboratories have not yet taken up automated cell population identification methods, though among those that have, Infinicyt software is the most frequently identified. Survey respondents considered data output quality to be the most important factor when using automated FC data analysis software, followed by software speed and level of technical support. This review found differences in software usage between biomedical institutions, with tools for discovery, data exploration, and visualization more popular in academia, whereas automated tools for specialized targeted analysis that apply supervised learning methods were more used in clinical settings.

SummaryThe mitochondrial electron transport chain (ETC) includes an alternative oxidase (AOX) that may control the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS act as signaling intermediates in numerous plant processes, including stomatal movement.The role of AOX in controlling ROS and RNS concentrations under both steady-state and different stress conditions was evaluated using Nicotiana tabacum plants lacking AOX as a result of RNA interference. A potential functional implication of changes in ROS and RNS homeostasis was also evaluated by examining stomatal function.The leaves of nonstressed AOX knockdowns maintained concentrations of H 2 O 2 and nitric oxide (NO) normally seen in wildtype plants only under stress conditions. Further, guard cell NO amounts were much higher in knockdowns. These guard cells were altered in size and were less responsive to NO as a signal for stomatal closure. This, in turn, compromised the stomatal response to changing irradiance.The results reveal a role for AOX in stomata. A working model is that guard cell AOX respiration maintains NO homeostasis by preventing over-reduction of the ETC, particularly during periods when high concentrations of NO acting as a signal for stomatal closure may also be inhibiting cyt oxidase respiration.