The expression of c-Met pathway components in unclassified pleomorphic sarcoma/malignant fibrous histiocytoma (UPS/MFH): a tissue microarray study.

Aims: Subclassification of undifferentiated pleomorphic sarcoma/malignant fibrous histiocytoma (UPS/MFH) into distinct biological cohorts based on the expression patterns of molecular markers can identify patient subsets with especially unfavourable clinical outcomes. Identification of molecular prognosticators amenable for drug targeting can facilitate rational development of UPS/MFH tailored therapies. The aim was to evaluate expression of c-Met pathway components in a large cohort of UPS/MFH samples.

Combining EGFR and mTOR blockade for the treatment of epithelioid sarcoma.

Purpose: Molecular deregulations underlying epithelioid sarcoma (ES) progression are poorly understood yet critically needed to develop new therapies. Epidermal growth factor receptor (EGFR) is overexpressed in ES; using preclinical models, we examined the ES EGFR role and assessed anti-ES EGFR blockade effects, alone and with mTOR inhibition.

Experimental Design: EGFR and mTOR expression/activation was examined via tissue microarray (n = 27 human ES specimens; immunohistochemistry) and in human ES cell lines (Western blot and quantitative reverse transcriptase PCR).

G-CSF receptor activation of the Src kinase Lyn is mediated by Gab2 recruitment of the Shp2 phosphatase.

Src activation involves the coordinated regulation of positive and negative tyrosine phosphorylation sites. The mechanism whereby receptor tyrosine kinases, cytokine receptors, and integrins activate Src is not known. Here, we demonstrate that granulocyte colony-stimulating factor (G-CSF) activates Lyn, the predominant Src kinase in myeloid cells, through Gab2-mediated recruitment of Shp2.

Activated MET is a molecular prognosticator and potential therapeutic target for malignant peripheral nerve sheath tumors.

Purpose: MET signaling has been suggested a potential role in malignant peripheral nerve sheath tumors (MPNST). Here, MET function and blockade were preclinically assessed.

Experimental Design: Expression levels of MET, its ligand hepatocyte growth factor (HGF), and phosphorylated MET (pMET) were examined in a clinically annotated MPNST tissue microarray (TMA) incorporating univariable and multivariable statistical analyses.

Vimentin is a novel anti-cancer therapeutic target; insights from in vitro and in vivo mice xenograft studies.

Background: Vimentin is a ubiquitous mesenchymal intermediate filament supporting mechano-structural integrity of quiescent cells while participating in adhesion, migration, survival, and cell signaling processes via dynamic assembly/disassembly in activated cells. Soft tissue sarcomas and some epithelial cancers exhibiting "epithelial to mesenchymal transition" phenotypes express vimentin. Withaferin-A, a naturally derived bioactive compound, may molecularly target vimentin, so we sought to evaluate its effects on tumor growth in vitro and in vivo thereby elucidating the role of vimentin in drug-induced responses.

Dual targeting of AKT and mammalian target of rapamycin: a potential therapeutic approach for malignant peripheral nerve sheath tumor.

The mammalian target of rapamycin (mTOR) pathway may constitute a potential target for the treatment of malignant peripheral nerve sheath tumors (MPNST). However, investigations of other cancers suggest that mTOR blockade can paradoxically induce activation of prosurvival, protumorigenic signaling molecules, especially upstream AKT. Consequently, we hypothesized that dual phosphatidylinositol 3-kinase (PI3K)/AKT-mTOR blockade might be applicable for MPNST treatment.

Combining PCI-24781, a novel histone deacetylase inhibitor, with chemotherapy for the treatment of soft tissue sarcoma.

Purpose: Histone deactylase inhibitors (HDACi) are a promising new class of anticancer therapeutics; however, little is known about HDACi activity in soft tissue sarcoma (STS), a heterogeneous cohort of mesenchymal origin malignancies. Consequently, we investigated the novel HDACi PCI-24781, alone/in combination with conventional chemotherapy, to determine its potential anti-STS-related effects and the underlying mechanisms involved.

Experimental Design: Immunoblotting was used to evaluate the effects of PCI-24781 on histone and nonhistone protein acetylation and expression of potential downstream targets.

Increased vascular endothelial growth factor-C expression is insufficient to induce lymphatic metastasis in human soft-tissue sarcomas.

Purpose: Unlike carcinomas, soft-tissue sarcoma (STS) rarely exhibit lymphatic spread. Consequently, we examined expression and function of vascular endothelial growth factor (VEGF)-C and STS-associated lymphatic vessel density (LVD) components of this process.

Experimental Design: VEGF-C and VEGF-A mRNA and VEGF-C protein expression were evaluated in STS, STS cell lines, and breast cancers (reverse transcription-PCR, quantitative reverse transcription-PCR, and ELISA).

Midkine enhances soft-tissue sarcoma growth: a possible novel therapeutic target.

Purpose: New therapeutic targets for soft-tissue sarcoma (STS) treatment are critically needed. Midkine (MK), a multifunctional cytokine, is expressed during midgestation but is highly restricted in normal adult tissues. Renewed MK expression was shown in several malignancies where protumorigenic properties were described.

Epidermal growth factor receptor blockade in combination with conventional chemotherapy inhibits soft tissue sarcoma cell growth in vitro and in vivo.

Purpose: The epidermal growth factor receptor (EGFR) is highly expressed in many human soft tissue sarcomas (STS). However, EGFR blockade has not apparently been used for human STS therapy; therefore, we examined the in vitro and in vivo effects and the underlying mechanisms before considering EGFR blockade as a therapy for STS patients.

Experimental Design: Human STS tissues and cell lines were used to study EGFR expression and activation.

Soft tissue sarcoma cells are highly sensitive to AKT blockade: a role for p53-independent up-regulation of GADD45 alpha.

The AKT signaling pathway is activated in soft tissue sarcoma (STS). However, AKT blockade has not yet been studied as a potential targeted therapeutic approach. Here, we examined the in vitro and in vivo effects of AKT inhibition in STS cells.

Rad51 overexpression contributes to chemoresistance in human soft tissue sarcoma cells: a role for p53/activator protein 2 transcriptional regulation.

We investigated whether Rad51 overexpression plays a role in soft tissue sarcoma (STS) chemoresistance as well as the regulatory mechanisms underlying its expression. The studies reported here show that Rad51 protein is overexpressed in a large panel of human STS specimens. Human STS cell lines showed increased Rad51 protein expression, as was also observed in nude rat STS xenografts.

The Integrin alpha9beta1 contributes to granulopoiesis by enhancing granulocyte colony-stimulating factor receptor signaling.

The integrin alpha9beta1 is widely expressed on neutrophils, smooth muscle, hepatocytes, endothelia, and some epithelia. We now show that mice lacking this integrin have a dramatic defect in neutrophil development, with decreased numbers of granulocyte precursors in bone marrow and impaired differentiation of bone marrow cells into granulocytes. In response to granulocyte colony-stimulating factor (G-CSF), alpha9-deficient bone marrow cells or human bone marrow cells incubated with alpha9beta1-blocking antibody demonstrated decreased phosphorylation of signal transducer and activator of transcription 3 and extracellular signal-regulated protein kinase.

Src kinases in G-CSF receptor signaling.

The Granulocyte Colony-Stimulating Factor (G-CSF) receptor, a member of the hematopoietin cytokine receptor superfamily, functions as a homodimer and requires the recruitment of cytosolic protein tyrosine kinases (PTKs) to transduce its signal. At least two cytosolic PTKs are primarily involved: Jak2, a member of the Janus family, and Lyn, a member of the Src family. Through poorly understood mechanisms, these kinases functionally interact with the G-CSF receptor.

G-CSF induced reactive oxygen species involves Lyn-PI3-kinase-Akt and contributes to myeloid cell growth.

Granulocyte colony-stimulating factor (G-CSF) drives the production, survival, differentiation, and inflammatory functions of granulocytes. Reactive oxygen species (ROSs) provide a major thrust of the inflammatory response, though excessive ROSs may be deleterious. G-CSF stimulation showed a time- and dose-dependent increase in ROS production, correlating with activation of Lyn and Akt.

G-CSF-induced tyrosine phosphorylation of Gab2 is Lyn kinase dependent and associated with enhanced Akt and differentiative, not proliferative, responses.

The granulocyte colony-stimulating factor receptor (G-CSFR) transduces intracellular signals for myeloid cell proliferation, survival, and differentiation through the recruitment of nonreceptor protein tyrosine kinases Lyn and janus kinase 2 (Jak2). This results in the tyrosine phosphorylation of a small set of positive and negative adapters and effectors. Grb2-associated binder-2 (Gab2) is a newly described adapter molecule, preferentially expressed in hematopoietic cells and associated with phosphatidylinositol 3 (PI3) kinase.

Deletional mutation of the external domain of the human granulocyte colony-stimulating factor receptor in a patient with severe chronic neutropenia refractory to granulocyte colony-stimulating factor.

Severe chronic neutropenia (SCN) is characterized by a profound neutropenia, which mostly presents during the neonatal period. The precise genetic basis of SCN remains elusive. Acquired somatic mutations involving the carboxy-terminus of the G-CSF receptor (G-CSFR) have been found, often in association with myelodysplastic syndrome.

PMA Stimulated Hydrolysis of Phosphatidylcholine in CRBH7919 Cell and Its Enzymatic Basis.

The effect of phorbol 12-myristate-13-acetate (PMA) on the hydrolysis of phosphatidylcholine (PC) in rat hepatoma cell line CRBH7919 has been studied. It was found that PMA stimulated PC hydrolysis in CRBH7919 cells in a dose-dependent manner after treatment for 15 min. The product of PC hydrolysis was choline, not phosphocholine.