Senescent cancer-associated fibroblasts in pancreatic adenocarcinoma restrict CD8 T cell activation and limit responsiveness to immunotherapy in mice.

Senescent cells within tumors and their stroma exert complex pro- and anti-tumorigenic functions. However, the identities and traits of these cells, and the potential for improving cancer therapy through their targeting, remain poorly characterized. Here, we identify a senescent subset within previously-defined cancer-associated fibroblasts (CAFs) in pancreatic ductal adenocarcinomas (PDAC) and in premalignant lesions in mice and humans.

Senescence of human pancreatic beta cells enhances functional maturation through chromatin reorganization and promotes interferon responsiveness.

Senescent cells can influence the function of tissues in which they reside, and their propensity for disease. A portion of adult human pancreatic beta cells express the senescence marker p16, yet it is unclear whether they are in a senescent state, and how this affects insulin secretion. We analyzed single-cell transcriptome datasets of adult human beta cells, and found that p16-positive cells express senescence gene signatures, as well as elevated levels of beta-cell maturation genes, consistent with enhanced functionality.

Regulation of Cellular Heterogeneity and Rates of Symmetric and Asymmetric Divisions in Triple-Negative Breast Cancer.

Differentiation events contribute to phenotypic cellular heterogeneity within tumors and influence disease progression and response to therapy. Here, we dissect mechanisms controlling intratumoral heterogeneity within triple-negative basal-like breast cancers. Tumor cells expressing the cytokeratin K14 possess a differentiation state that is associated with that of normal luminal progenitors, and K14-negative cells are in a state closer to that of mature luminal cells.

Programming asynchronous replication in stem cells.

Many regions of the genome replicate asynchronously and are expressed monoallelically. It is thought that asynchronous replication may be involved in choosing one allele over the other, but little is known about how these patterns are established during development. We show that, unlike somatic cells, which replicate in a clonal manner, embryonic and adult stem cells are programmed to undergo switching, such that daughter cells with an early-replicating paternal allele are derived from mother cells that have a late-replicating paternal allele.

Inflammation-Induced Expression and Secretion of MicroRNA 122 Leads to Reduced Blood Levels of Kidney-Derived Erythropoietin and Anemia.

Background & Aims: Anemia is associated commonly with acute and chronic inflammation, but the mechanisms of their interaction are not clear. We investigated whether microRNA 122 (MIR122), which is generated in the liver and is secreted into the blood, is involved in the development of anemia associated with inflammation.

Methods: We characterized the primary transcript of the human liver-specific MIR122 using Northern blot, quantitative real-time polymerase chain reaction, and 3' and 5' rapid amplification of cDNA ends analyses.

Directed elimination of senescent cells by inhibition of BCL-W and BCL-XL.

Senescent cells, formed in response to physiological and oncogenic stresses, facilitate protection from tumourigenesis and aid in tissue repair. However, accumulation of such cells in tissues contributes to age-related pathologies. Resistance of senescent cells to apoptotic stimuli may contribute to their accumulation, yet the molecular mechanisms allowing their prolonged viability are poorly characterized.

p16(Ink4a)-induced senescence of pancreatic beta cells enhances insulin secretion.

Cellular senescence is thought to contribute to age-associated deterioration of tissue physiology. The senescence effector p16(Ink4a) is expressed in pancreatic beta cells during aging and limits their proliferative potential; however, its effects on beta cell function are poorly characterized. We found that beta cell-specific activation of p16(Ink4a) in transgenic mice enhances glucose-stimulated insulin secretion (GSIS).

Evolving views of breast cancer stem cells and their differentiation States.

Cellular heterogeneity is a prominent characteristic of breast cancers, and accumulating evidence indicates that variability in the differentiation state of tumor cells contributes to this phenomenon. Breast cancers are among the tumor types in which the existence of cancer stem cells has been widely supported, and specific markers, including CD44/CD24 and ALDH1, have been consistently used to identify such cells. Recent studies have revealed the potential for dynamic bidirectional transitions of breast cancer cells between differentiated and stem-like phenotypes.

Transduction of fetal mice with a feline lentiviral vector induces liver tumors which exhibit an E2F activation signature.

Lentiviral vectors are widely used in basic research and clinical applications for gene transfer and long-term expression; however, safety issues have not yet been completely resolved. In this study, we characterized hepatocarcinomas that developed in mice 1 year after in utero administration of a feline-derived lentiviral vector. Mapped viral integration sites differed among tumors and did not coincide with the regions of chromosomal aberrations.

Gene transfer to chicks using lentiviral vectors administered via the embryonic chorioallantoic membrane.

The lack of affordable techniques for gene transfer in birds has inhibited the advancement of molecular studies in avian species. Here we demonstrate a new approach for introducing genes into chicken somatic tissues by administration of a lentiviral vector, derived from the feline immunodeficiency virus (FIV), into the chorioallantoic membrane (CAM) of chick embryos on embryonic day 11. The FIV-derived vectors carried yellow fluorescent protein (YFP) or recombinant alpha-melanocyte-stimulating hormone (α-MSH) genes, driven by the cytomegalovirus (CMV) promoter.

Neonatal gene therapy of glycogen storage disease type Ia using a feline immunodeficiency virus-based vector.

Glycogen storage disease type Ia (GSD-Ia), also known as von Gierke disease, is caused by a deficiency of glucose-6-phosphatase-alpha (G6Pase), a key enzyme in glucose homeostasis. From birth, affected individuals cannot maintain normal blood glucose levels and suffer from a variety of metabolic disorders, leading to life-threatening complications. Gene therapy has been proposed as a possible option for treatment of this illness.

Prolonged transgene expression in murine salivary glands following non-primate lentiviral vector transduction.

Salivary glands are an accessible organ for gene therapy, enabling expression of recombinant proteins for both exocrine and endocrine secretion. Lentivirus-based vectors have many advantages for gene therapy, including their ability to infect nondividing cells and to stably integrate into the host genome, enabling long-term transgene expression without eliciting an inflammatory immune response. In the present study, murine salivary glands were inoculated with feline immunodeficiency virus (FIV)-based lentiviral vectors expressing various reporter genes.

Prolonged liver-specific transgene expression by a non-primate lentiviral vector.

Liver-directed gene therapy has the potential for treatment of numerous inherited diseases affecting metabolic functions. The aim of this study was to evaluate gene expression in hepatocytes using feline immunodeficiency virus-based lentiviral vectors, which may be potentially safer than those based on human immunodeficiency virus. In vitro studies revealed that gene expression was stable for up to 24 days post-transduction and integration into the host cell genome was suggested by Alu PCR and Southern blot analyses.