Abstract Gastrointestinal stromal sarcomas (GISTs) are the most common mesenchymal tumours originating in the digestive tract. They have a characteristic morphology, are generally positive for CD117 ...(c-kit) and are primarily caused by activating mutations in the KIT or PDGFRA genes (1) . On rare occasions, they occur in extravisceral locations such as the omentum, mesentery, pelvis and retroperitoneum. GISTs have become a model of multidisciplinary work in oncology: the participation of several specialties (oncologists, pathologists, surgeons, molecular biologists, radiologists…) has forested advances in the understanding of this tumour and the consolidation of a targeted therapy, imatinib, as the first effective molecular treatment in solid tumours. Following its introduction, median survival of patients with advanced or metastatic GIST increased from 18 to more than 60 months. Sunitinib and Regorafenib are two targeted agents with worldwide approval for second- and third-line treatment, respectively, in metastatic GIST.
Abstract Emerging data suggests that host immune cells with a suppressive phenotype represent a significant hurdle to successful therapy for metastatic cancer. Among the suppressor cells, T ...regulatory cells (Treg) and myeloid-derived suppressor cells (MDSC) are significantly increased in hosts with advanced malignancies. MDSC mediate the suppression of the tumor antigen-specific T cell response through the induction of T cell anergy and the development of Treg in tumor-bearing mice. These results provide robust evidence of an in vivo immunoregulatory function of MDSC in the establishment of tumor antigen-specific tolerance and the development of Treg in tumor-bearing hosts. To achieve effective anti-tumor immunity, tumor-induced immunosuppression must be reversed. Our preliminary results indicate that c-kit ligand (stem cell factor) expressed by tumor cells may be required for MDSC accumulation in tumor-bearing mice, and that blocking the c-kit ligand/c-kit receptor interaction can prevent the development of Treg and reverse immune tolerance induced by MDSC. Since c-kit can be readily inhibited by several small molecule inhibitors including imatinib, sunitinib and dasatinib, targeting immune suppressing cells can be readily accomplished in the clinic.
Fluoroquinolones trigger anaphylaxis during clinical applications, affecting the safety of their administration. Mast cells are immune cells that act as sentinels during host defenses, mediating ...hypersensitivity and anaphylactic reactions. Mas-related G protein-coupled receptor X2 (MRGPRX2) is a mast cell-specific receptor that mediates cell degranulation in anaphylactic reactions. In this study, the mechanism underpinning the anaphylactic reactions caused by fluoroquinolones was investigated. Hypersensitivity was assessed through hindpaw swelling, tissue fluid leakage assays, in vivo and body temperature measurements assay in vivo, and cell calcium mobilization assays, and mast cell degranulation assays in vitro. Mast cell-deficient W-sash c-kit mutant KitW-sh/W-sh mice and MrgprB2 (the orthologous receptor of MRGPRX2 in mice) knockout mice exhibited reduced fluoroquinolone-induced anaphylactic effects. Fluoroquinolones activated mast cells in a dose-dependent manner and reduced degranulation was observed following MRGPRX2 silencing. These results reveal that fluoroquinolone-induced anaphylactic reactions are mediated by mast cells through MRGPRX2.
Display omitted
•The mechanism underpinning the anaphylactic reactions caused by fluoroquinolones is proposed.•Mast cell-deficient KitW-sh/W-sh mice and MrgprB2 knockout mice exhibited reduced anaphylactic effects compared with WT mice.•Fluoroquinolones activated mast cells dose-dependently and reduced degranulation was observed following MRGPRX2 silencing.•The mechanism relies on fluoroquinolones-triggered mast cells activation via MRGPRX2.
Bone loss, in malignant or non-malignant diseases, is caused by increased osteoclast resorption and/or reduced osteoblast bone formation, and is commonly associated with skeletal complications. Thus, ...there is a need to identify new agents capable of influencing bone remodeling. We aimed to further pre-clinically evaluate the effects of dasatinib (BMS-354825), a multitargeted tyrosine kinase inhibitor, on osteoblast and osteoclast differentiation and function.
For studies on osteoblasts, primary human bone marrow mensenchymal stem cells (hMSCs) together with the hMSC-TERT and the MG-63 cell lines were employed. Osteoclasts were generated from peripheral blood mononuclear cells (PBMC) of healthy volunteers. Skeletally-immature CD1 mice were used in the in vivo model.
Dasatinib inhibited the platelet derived growth factor receptor-β (PDGFR-β), c-Src and c-Kit phosphorylation in hMSC-TERT and MG-63 cell lines, which was associated with decreased cell proliferation and activation of canonical Wnt signaling. Treatment of MSCs from healthy donors, but also from multiple myeloma patients with low doses of dasatinib (2-5 nM), promoted its osteogenic differentiation and matrix mineralization. The bone anabolic effect of dasatinib was also observed in vivo by targeting endogenous osteoprogenitors, as assessed by elevated serum levels of bone formation markers, and increased trabecular microarchitecture and number of osteoblast-like cells. By in vitro exposure of hemopoietic progenitors to a similar range of dasatinib concentrations (1-2 nM), novel biological sequelae relative to inhibition of osteoclast formation and resorptive function were identified, including F-actin ring disruption, reduced levels of c-Fos and of nuclear factor of activated T cells 1 (NFATc1) in the nucleus, together with lowered cathepsin K, αVβ3 integrin and CCR1 expression.
Low dasatinib concentrations show convergent bone anabolic and reduced bone resorption effects, which suggests its potential use for the treatment of bone diseases such as osteoporosis, osteolytic bone metastasis and myeloma bone disease.
Sets of 3-alkenyl-2-oxindoles were synthesized of potential antiproliferative (against PaCa-2 and MCF7cancer cell lines) and promising properties against SARS-CoV-2.
Display omitted
...•3-Alkenyl-2-oxindoles were prepared in a facile synthetic pathway.•The synthesized agents show potent properties against PaCa2 cell line.•CAM assay reveals the anti-angiogenic properties of the targeted agents.•The agents synthesized show multi-targeted inhibitory properties against VEGFR-2 and c-kit.•Antiviral properties against SARS-CoV-2 and high SI were revealed by the synthesized agents.
Sets of 3-alkenyl-2-oxindoles (6,10,13) were synthesized in a facile synthetic pathway through acid dehydration (EtOH/HCl) of the corresponding 3-hydroxy-2-oxoindolines (5,9,12). Single crystal (10a,c) and powder (12a,26f) X-ray studies supported the structures. Compounds 6c and 10b are the most effective agents synthesized (about 3.4, 3.3 folds, respectively) against PaCa2 (pancreatic) cancer cell line relative to the standard reference used (Sunitinib). Additionally, compound 10b reveals antiproliferative properties against MCF7 (breast) cancer cell with IC50 close to that of Sunitinib. CAM testing reveals that compounds 6 and 10 demonstrated qualitative and quantitative decreases in blood vessel count and diameter with efficacy comparable to that of Sunitinib, supporting their anti-angiogenic properties. Kinase inhibitory properties support their multi-targeted inhibitory activities against VEGFR-2 and c-kit in similar behavior to that of Sunitinib. Cell cycle analysis studies utilizing MCF7 exhibit that compound 6b arrests the cell cycle at G1/S phase while, 10b reveals accumulation of the tested cell at S phase. Compounds 6a and 10b reveal potent antiviral properties against SARS-CoV-2 with high selectivity index relative to the standards (hydroxychloroquine, chloroquine). Safe profile of the potent synthesized agents, against normal cells (VERO-E6, RPE1), support the possible development of better hits based on the attained observations.
•A novel simulator for two types of sonars used in underwater applications.•For real-time applications rather than existing approaches.•Scenarios produced more realistically than other simulators.
...Display omitted
Mainly when applied in the underwater environment, sonar simulation requires great computational effort due to the complexity of acoustic physics. Simulation of sonar operation allows evaluating algorithms and control systems without going to the real underwater environment; that reduces the costs and risks of in-field experiments. This paper tackles with the problem of real-time underwater imaging sonar simulation by using the OpenGL shading language chain on GPU. Our proposed system is able to simulate two main types of acoustic devices: mechanical scanning imaging sonars and forward-looking sonars. The underwater scenario simulation is performed based on three frameworks: (i) OpenSceneGraph reproduces the ocean visual effects, (ii) Gazebo deals with physical forces, and (iii) the Robot Construction Kit controls the sonar in underwater environments. Our system exploits the rasterization pipeline in order to simulate the sonar devices, which are simulated by means of three parameters: the pulse distance, the echo intensity and the sonar field-of-view, being all calculated over observable objects shapes in the 3D rendered scene. Sonar-intrinsic operational parameters, speckle noise and object material properties are also considered as part of the acoustic image. Our evaluation demonstrated that the proposed system is able to operate close to or faster than the real-world devices. Also, our method generates visually realistic sonar images when compared with real-world sonar images of the same scenes.
Myeloid-derived suppressor cells (MDSCs) contribute to tumor-mediated immune escape and negatively correlate with overall survival of cancer patients. Nowadays, a variety of methods to target MDSCs ...are being investigated. Based on the intervention stage of MDSCs, namely development, expansion and activation, function and turnover, these methods can be divided into: (I) prevention or differentiation to mature cells, (II) blockade of MDSC expansion and activation, (III) inhibition of MDSC suppressive activity or (IV) depletion of intratumoral MDSCs. This review describes effective mono- or multimodal-therapies that target MDSCs for the benefit of cancer treatment.
Aggressive systemic mastocytosis (ASM) is a very rare form of mast cell neoplasm that does not benefit from conventional chemotherapy. The majority of adult mast cell neoplasms and gastrointestinal ...stromal tumors (GISTs) have mutations in the proto-oncogene c-kit, which encodes the KIT receptor tyrosine kinase. The c-kit gene mutations are generally confined to the tyrosine kinase II domain in mast cell neoplasms, but are often observed at the juxtamembrane domain in GISTs. We found a case of ASM with a juxtamembrane-type mutation, Val559Ile, and in this report the mutation was characterized through transfection of the mutated c-kit cDNA into human embryonic kidney cells. Phosphorylation of KIT and its possible downstream signaling molecules were examined in the presence or absence of imatinib, a selective tyrosine kinase inhibitor. Ligand-independent autophosphorylation was observed in the mutant KIT with Val559Ile as well as that with Val559Asp, as found in GISTs. Imatinib, at a concentration of 10 μM, inhibited autophosphorylation of the mutant KIT with Val559Asp, but not that with the Val559Ile. Phosphorylation of MAPK and STAT5 was also inhibited by imatinib at the same concentration, in cells expressing Val559Asp but not in those expressing Val559Ile. These results suggest that different mutations, even at the same codon, in juxtamembrane domain of the c-kit gene show different inhibitory effects of imatinib, and that patients with GISTs or mast cell neoplasms possessing this Val559Ile mutation are resistant to imatinib therapy.
We describe the presence of interstitial cells of Cajal (ICC) throughout the wall of the guinea pig bladder.
Bladders obtained from male guinea pigs were prepared for immunohistochemical ...investigations using various primary antibodies, including the specific ICC marker c-kit (Gibco BRL, Grand Island, New York). Enzymatically dispersed cells with a branched morphology were identified as ICC using anti-c-kit. They were loaded with fluo-4acetoxymethyl (Molecular Probes, Eugene, Oregon) and studied using confocal laser scanning microscopy.
Anti-c-kit labeling demonstrated that ICC were oriented in parallel with the smooth muscle bundles that run diagonally throughout the bladder. Double labeling with anti-smooth muscle myosin (Sigma Chemical Co., St. Louis, Missouri) revealed that ICC were located on the boundary of smooth muscle bundles. When anti-c-kit was used in combination with the general neuronal antibody protein gene product 9.5 (Ultraclone Ltd., Isle of Wight, United Kingdom) or anti-neuronal nitric oxide synthase, it was noted that there was a close association between nerves and ICC. Enzymatic dissociation of cells from tissue pieces yielded a heterogeneous population of cells containing typical spindle-shaped smooth muscle cells and branched cells resembling ICC from other preparations. The latter could be identified immunohistochemically as ICC using anti-c-kit, whereas the majority of spindle-shaped cells were not Kit positive. Branched cells responded to the application of carbachol by firing Ca
2+ waves and they were often spontaneously active.
ICC are located on the boundary of smooth muscle bundles in the guinea pig bladder. They fire Ca
2+ waves in response to cholinergic stimulation and can be spontaneously active, suggesting that they could act as pacemakers or intermediaries in the transmission of nerve signals to smooth muscle cells.
We recently characterized gene expression patterns in gastrointestinal stromal tumors (GISTs) using cDNA microarrays, and found that the gene
FLJ10261
(
DOG1
, discovered on GIST-1), encoding a ...hypothetical protein, was specifically expressed in GISTs. The immunoreactivity of a rabbit antiserum to synthetic DOG1 peptides was assessed on two soft tissue tumor microarrays. The tissue microarrays included 587 soft tissue tumors, with 149 GISTs, including 127 GIST cases for which the
KIT
and
PDGFRA
mutation status was known. Immunoreactivity for DOG1 was found in 136 of 139 (97.8%) of scorable GISTs. All seven GIST cases with a
PDGFRA
mutation were DOG1-positive, while most of these failed to react for KIT. The immunohistochemical findings were confirmed with
in situ
hybridization probes for
DOG1
,
KIT
, and
PDGFRA
. Other neoplasms in the differential diagnosis of GIST, including desmoid fibromatosis (0 of 17) and Schwannoma (0 of 3), were immunonegative for DOG1. Only 4 of 438 non-GIST cases were immunoreactive for DOG1. DOG1, a protein of unknown function, is expressed strongly on the cell surface of GISTs and is rarely expressed in other soft tissue tumors. Reactivity for DOG1 may aid in the diagnosis of GISTs, including
PDGFRA
mutants that fail to express KIT antigen, and lead to appropriate treatment with imatinib mesylate, an inhibitor of the KIT tyrosine kinase.
PDF
