Airway cilia provide the coordinated motive force for mucociliary transport, which prevents the accumulation of mucus, debris, pollutants, and bacteria in our respiratory tracts. As airway cilia are constantly exposed to the environment and, hence, are an integral component of the pathogenesis of several congenital and chronic pulmonary disorders, it is necessary to understand the molecular mechanisms that control ciliated cell differentiation and ciliogenesis. We have previously reported that loss of the basal body protein Chibby (Cby) results in chronic upper airway infection in mice due to a significant reduction in the number of airway cilia. In the present work, we demonstrate that Cby is required for normal ciliary structure and proper distribution of proteins involved in the bidirectional intraflagellar transport (IFT) system, which consists of 2 distinct sub-complexes, IFT-A and IFT-B, and is essential for ciliary biogenesis and maintenance. In fully differentiated ciliated cells, abnormal paddle-like cilia with dilated ciliary tips are observed in Cby-/- airways and primary cultures of mouse tracheal epithelial cells (MTECs). In addition, IFT88, an IFT-B sub-complex protein, robustly accumulates within the dilated tips of both multicilia in Cby-/- MTECs and primary cilia in Cby-/- mouse embryonic fibroblasts (MEFs). Furthermore, we show that only IFT-B components, including IFT20 and IFT57, but not IFT-A and Bardet-Biedl syndrome (BBS) proteins, amass with IFT88 in these distended tips in Cby-/- ciliated cells. Taken together, our findings suggest that Cby plays a role in the proper distribution of IFT particles to preserve normal ciliary morphology in airway ciliated cells.
The mother centriole of the centrosome is distinguished from immature daughter centrioles by the presence of accessory structures (distal and subdistal appendages), which play an important role in the organization of the primary cilium in quiescent cells. Primary cilia serve as sensory organelles, thus have been implicated in mediating intracellular signal transduction pathways. Here we report that Chibby (Cby), a highly conserved antagonist of the Wnt/β-catenin pathway, is a centriolar component specifically located at the distal end of the mother centriole and essential for assembly of the primary cilium. Cby appeared as a discrete dot in the middle of a ring-like structure revealed by staining with a distal appendage component of Cep164. Cby interacted with one of the appendage components, Cenexin (Cnx), which thereby abrogated the inhibitory effect of Cby on β-catenin-mediated transcriptional activation in a dose-dependent manner. Cby and Cnx did not precisely align, as Cby was detected at a more distal position than Cnx. Cnx emerged earlier than Cby during the cell cycle and was required for recruitment of Cby to the mother centriole. However, Cby was dispensable for Cnx localization to the centriole. During massive centriogenesis in in vitro cultured mouse tracheal epithelial cells, Cby and Cnx were expressed in a similar pattern, which was coincident with the expression of Foxj1. Our results suggest that Cby plays an important role in organization of both primary and motile cilia in collaboration with Cnx.
Abstract Methods were compared for controlling volunteer horseradish ( Armoracia rusticana Gaertn, Mey. & Scherb.) resulting from commercial horseradish production. The most effective treatment was glyphosate [N-(phosphonomethyl) glycine] (4.5 kg/ha) applied in mid-September 6 to 8 weeks after discing. 2,4,5-T [2,4,5-trichloro-phenoxy acetic acid] was also effective, while dicamba [3,6,dichloro-o-anisic acid] and a dicamba plus glyphosate mixture provided less control. Horseradish roots can sprout from 90-cm deep and still be susceptible to a mid-September glyphosate application.
The canonical Wnt/β-catenin pathway plays crucial roles in various aspects of lung morphogenesis and regeneration/repair. Here, we examined the lung phenotype and function in mice lacking the Wnt/β-catenin antagonist Chibby (Cby). In support of its inhibitory role in canonical Wnt signaling, expression of β-catenin target genes is elevated in the Cby−/− lung. Notably, Cby protein is prominently associated with the centrosome/basal body microtubule structures in embryonic lung epithelial progenitor cells, and later enriches as discrete foci at the base of motile cilia in airway ciliated cells. At birth, Cby−/− lungs are grossly normal but spontaneously develop alveolar airspace enlargement with reduced proliferation and abnormal differentiation of lung epithelial cells, resulting in altered pulmonary function. Consistent with the Cby expression pattern, airway ciliated cells exhibit a marked paucity of motile cilia with apparent failure of basal body docking. Moreover, we demonstrate that Cby is a direct downstream target for the master ciliogenesis transcription factor Foxj1. Collectively, our results demonstrate that Cby facilitates proper postnatal lung development and function.
To determine the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), pharmacokinetics, and pharmacodynamics of sorafenib in children with refractory extracranial solid tumors and evaluate the tolerability of the solid tumor MTD in children with refractory leukemias.Sorafenib was administered orally every 12 hours for consecutive 28-day cycles. Pharmacokinetics (day 1 and steady-state) and pharmacodynamics were conducted during cycle 1.Of 65 patients enrolled, 60 were eligible. In the solid tumor cohort (n = 49), 4 of 6 patients experienced a DLT [hypertension, pain, rash/urticaria, thrombocytopenia, alanine aminotransferase (ALT)/aspartate aminotransferase (AST)] at the starting dose (150 mg/m(2)/dose) which resulted in de-escalation to 105 mg/m(2)/dose. After eligibility criteria modification and dose re-escalation, the MTD was 200 mg/m(2)/dose for solid tumors and 150 mg/m(2)/dose for leukemias. Sorafenib exposure was highly variable between patients but was within the ranges reported in adults. The apparent sorafenib clearance increased with patient age. Diarrhea, rash, fatigue, and increased ALT/AST were the most common sorafenib-related toxicities. Stable disease for 4 or more cycles was observed in 14 solid tumor patients, and 2 patients with acute myeloid leukemia (AML) and FLT3 internal tandem duplication (FLT3ITD) experienced a decrease in bone marrow blasts to less than 5%.The recommended phase II dose of sorafenib administered every 12 hours continuously for children with solid tumors is 200 mg/m(2)/dose and 150 mg/m(2)/dose for children with leukemias. Sorafenib toxicities and distribution in children are similar to adults. The activity of sorafenib in children with AML and FLT3ITD is currently being evaluated, and a phase II study for select solid tumors is ongoing.
With proven efficacy of the use of immunotherapy in almost all stages of NSCLC, immunotherapy toxicity has become a very important topic that requires immediate recognition and management. The diagnosis of toxicities associated with immunotherapy in lung cancer can be very challenging and often requires multidisciplinary effort. This mini review gives an overview of the diagnosis and management of immune-related adverse events that arise from using immunotherapy in NSCLC, as well as the potential biomarkers for its early identification and future directions.
Intravenous (IV) topotecan is approved for the treatment of various malignancies including lung cancer but its clinical use is greatly undermined by severe hematopoietic toxicity. We hypothesized that inhalation delivery of topotecan would increase local exposure and efficacy against lung cancer while reducing systemic exposure and toxicity. These hypotheses were tested in a preclinical setting using a novel inhalable formulation of topotecan against the standard IV dose. Respirable dry-powder of topotecan was manufactured through spray-drying technology and the pharmacokinetics of 0.14 and 0.79 mg/kg inhalation doses were compared with 0.7 mg/kg IV dose. The efficacy of four weekly treatments with 1 mg/kg inhaled vs. 2 mg/kg IV topotecan were compared to untreated control using an established orthotopic lung cancer model for a fast (H1975) and moderately growing (A549) human lung tumors in the nude rat. Inhalation delivery increased topotecan exposure of lung tissue by approximately 30-fold, lung and plasma half-life by 5- and 4-folds, respectively, and reduced the maximum plasma concentration by 2-fold than the comparable IV dose. Inhaled topotecan improved the survival of rats with the fast-growing lung tumors from 7 to 80% and reduced the tumor burden of the moderately-growing lung tumors over 5- and 10-folds, respectively, than the 2-times higher IV topotecan and untreated control (p
