Delta‐like canonical Notch ligand 3 (DLL3) is a member of the Delta/Serrate/Lag2 (DSL) Notch receptor ligand family and plays a crucial role in Notch signaling, which influences various cellular ...processes including differentiation, proliferation, survival, and apoptosis. DLL3 is expressed throughout the presomitic mesoderm and is localized to the rostral somatic compartments; mutations in DLL3 induce skeletal abnormalities such as spondylocostal dysostosis. Recently, DLL3 has attracted interest as a novel molecular target due to its high expression in neuroendocrine carcinoma of the lung. Moreover, a DLL3‐targeting Ab‐drug conjugate, rovalpituzumab tesirine (ROVA‐T), has been developed as a new treatment with proven antitumor activity. However, the development of ROVA‐T was suspended because of shorter overall survival compared to topotecan, the second‐line standard treatment. Thus, several studies on the mechanism and function of DLL3 in several malignancies are underway to find a new strategy for targeting DLL3. In this review, we discuss the roles of DLL3 in various malignancies and the future perspectives of DLL3‐related research, especially as a therapeutic target.
Delta‐like canonical Notch ligand 3 (DLL3) plays a pivotal role in maintaining malignant growth and is related to poor prognosis, especially in relatively rare neuroendocrine subtypes.
Pyrrolobenzodiazepine dimers are an emerging class of warhead in the field of antibody–drug conjugates (ADCs). Tesirine (SG3249) was designed to combine potent antitumor activity with desirable ...physicochemical properties such as favorable hydrophobicity and improved conjugation characteristics. One of the reactive imines was capped with a cathepsin B-cleavable valine-alanine linker. A robust synthetic route was developed to allow the production of tesirine on clinical scale, employing a flexible, convergent strategy. Tesirine was evaluated in vitro both in stochastic and engineered ADC constructs and was confirmed as a potent and versatile payload. The conjugation of tesirine to anti-DLL3 rovalpituzumab has resulted in rovalpituzumab-tesirine (Rova-T), currently under evaluation for the treatment of small cell lung cancer.
Small cell lung cancer (SCLC) is an aggressive tumor characterized by rapid doubling time and high propensity for early development of disseminated disease. Although most patients respond to initial ...therapy with a platinum doublet, the majority of those with limited stage and virtually all patients with metastatic disease eventually develop tumor progression for which there are limited treatment options. There have been no recent changes in the treatment of SCLC, with platinum plus etoposide and topotecan as the standard first-line and second-line respectively, neither showing survival benefit over the combination of cyclophosphamide, doxorubicin and vincristine, which was developed in the 1970s. More recently, a new understanding of the biology of SCLC has led to the development of novel drugs, of which the most promising are the immune checkpoint inhibitors and the antibody drug conjugate rovalpituzumab tesirine.
This article presents a novel Volterra model particularly suited to describe modulated microwave systems. The seRies expansiOn of the Volterra Approximation (ROVA), (ReeksOntwikkeling van de Volterra ...Approximatie in Dutch) model uses the Taylor series expansion of the frequency-domain Volterra kernels and their symmetries to avoid a combinatorical explosion in model parameters. ROVA is moreover linear in its model parameters and can hence be solved in linear least squares sense. It is parsimonious compared to other state-of-the-art models used for similar applications. Additionally, the interpretability of ROVA avoids the need for heuristics to tune its hyperparameters. The performance of the ROVA approach is compared to current state-of-the-art memory polynomials. Simulation and experimental validation on power amplifiers indicate that ROVA outperforms the memory polynomials with less model parameters and lower modeling error.
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell ...signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
We recently found that Yersinia pseudotuberculosis can be used as a model of persistent bacterial infections. We performed in vivo RNA-seq of bacteria in small cecal tissue biopsies at early and ...persistent stages of infection to determine strategies associated with persistence. Comprehensive analysis of mixed RNA populations from infected tissues revealed that Y. pseudotuberculosis undergoes transcriptional reprogramming with drastic down-regulation of T3SS virulence genes during persistence when the pathogen resides within the cecum. At the persistent stage, the expression pattern in many respects resembles the pattern seen in vitro at 26oC, with for example, up-regulation of flagellar genes and invA. These findings are expected to have impact on future rationales to identify suitable bacterial targets for new antibiotics. Other genes that are up-regulated during persistence are genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress, which indicates the influence of different environmental cues. We found that the Crp/CsrA/RovA regulatory cascades influence the pattern of bacterial gene expression during persistence. Furthermore, arcA, fnr, frdA, and wrbA play critical roles in persistence. Our findings suggest a model for the life cycle of this enteropathogen with reprogramming from a virulent to an adapted phenotype capable of persisting and spreading by fecal shedding.
Small cell lung cancer (SCLC) is a very aggressive malignancy characterized by high cellular proliferation and early metastatic spread. In fact, although SCLC is a chemosensitive and radiosensitive ...disease, the initial responsiveness to chemotherapy is usually followed by development of resistance and the prognosis remains poor with a median survival of less than 12 months in patients with extensive disease (ED-SCLC). Furthermore, no significant progress has been made over the last years, with no newly approved drug. For all these reasons, SCLC represents for the oncologists a major challenge and an exciting field of clinical research. In this review, we analyze the most promising advances in development for SCLC with a special focus on antiangiogenic treatments, immunotherapy, novel chemotherapeutic and targeted agents.
The standard treatment regimen has not yet been established for advanced pulmonary large cell neuroendocrine carcinoma (LCNEC) because of its rarity. LCNEC can be subdivided into 2 mutually exclusive ...molecular subgroups: STK11/KEAP1 and TP53 mutated with high neuroendocrine expression and transcriptional profile of ASCL1high/DLL3high/NOTCHlow (non-small cell lung carcinoma, NSCLC-like) or RB1 and TP53 mutated with reduced neuroendocrine markers and transcriptional pattern of ASCL1low/DLL3low/NOTCHhigh (small cell lung cancer, SCLC-like). Model-based clustering shows that SCLC has subdivided into 2 major proteomic subsets defined by either TTF-1high/c-MYClow or TTF-1low/c-MYChigh, which may correspond to 2 mutually exclusive molecular subgroups: NSCLC-like or SCLC-like, respectively. We herein investigated whether TTF-1 and c-MYC could be applied to LCNEC to identify distinct subsets immunohistochemically and assessed DLL3 expression in these subsets. The protein expression profile may be useful to select patients for potential efficacy of targeted therapies including aurora kinase inhibitors for MYC alterations or anti-DLL3 antibody-drug conjugates. TTF-1 and c-MYC expression was mutually exclusive in 25 of 27 (93%) cases; TTF-1+/c-MYC- in 10, TTF-1-/c-MYC+ in 15, and TTF-1+/c-MYC+ in 2. DLL3 expression was seen in 15 of 27 cases (56%). All 12 TTF-1+ LCNEC cases were positive for DLL3. Three of 15 (20%) TTF-1-/c-MYC+ cases showed DLL3 positivity. LCNEC could be separated into 2 subsets proteomically defined by TTF-1 and c-MYC expression, which may be suitable to guide treatment selection including aurora kinase inhibitors for c-MYC+ cases. TTF-1 positivity can serve as a surrogate marker for DLL3, but caution is necessary as 20% of TTF-1- cases showed DLL3 positivity.
The type VI secretion system (T6SS) is a versatile molecular machinery widely distributed in Gram-negative bacteria. The activity of the T6SS is tightly regulated by various mechanisms, including ...quorum sensing (QS), iron concentration, and transcriptional regulators. Here we demonstrated that the stringent response regulator, RelA, contributes to bacterial resistance to multiple environmental stresses in Yersinia pseudotuberculosis. We also revealed that the stress resistance function of stringent response (SR) was partially mediated by the general stress response T6SS4 system. RelA positively regulates the expression of T6SS4 to combat various stresses in response to nutrition starvation collectively mediated by the RovM and RovA regulators. These findings revealed not only the important role of T6SS4 in SR induced stress resistance, but also a new pathway to regulate T6SS4 expression in response to starvation stress.
O presente estudo pretende abordar a questão da reconstrução de sentidos de diálogos obtidos a partir de interceptações telefônicas. Assim, na primeira parte apresenta conceitos da semiótica e da ...epistemologia para, na segunda parte, aplica-los a um caso real. Tudo a fim de responder a dois questionamentos: (i) a reconstrução de sentidos de textos, palavras ou frases pode se dar de maneira independente do contexto de sua utilização?; (ii) como é possível conhecer o contexto de uma comunicação? A metodologia utilizada é a revisão bibliográfica de escritos da semiótica e da epistemologia, utilizando-se caso real para ilustrar.
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