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Small-molecule and antibody approaches to molecular chemotherapy of primary brain tumors.

High-grade primary brain tumors remain refractory to conventional treatment approaches, including radiotherapy and cytotoxic chemotherapy. Molecular neuro-oncology has now begun to clarify the transformed phenotype of these malignant tumors and identify oncogenic pathways that might be amenable to small-molecule and antibody 'targeted' therapy. Growth factor signaling pathways are often upregulated in these tumors and contribute to oncogenesis through autocrine and paracrine mechanisms. Excessive growth factor receptor stimulation can also lead to overactivity of the downstream Ras signaling p

Aldosterone stimulates proliferation of mesangial cells by activating mitogen-activated protein kinase 1/2, cyclin D1, and cyclin A.

Recently, attention has been focused on the role of aldosterone in the pathophysiology of hypertension and cardiovascular disease. Several clinical and experimental data support the hypothesis that aldosterone contributes to the progression of renal injury. However, the molecular mechanisms of the effects of aldosterone in signal transduction and the cell-cycle progression of mesangial cells are not well known. For determining the signaling pathway of aldosterone in cultured mesangial cells, the effects of aldosterone on the mitogen-activated protein kinase 1/2 (MAPK1/2) pathway and the promot

Na+/K+/Cl- cotransporter activates MAP-kinase cascade downstream to protein kinase C, and upstream to MEK.

In this study, we demonstrated that the specific inhibitors of the Na+/K+/Cl- cotransporter (NKCC1), bumetanide and furosemide, inhibited extracellular regulated kinase (ERK) phosphorylation in Balb/c 3T3 fibroblasts, stimulated with a variety of mitogens. In addition to fibroblast growth factor (FGF) shown before, the various mitogens tested in the present study (endothelial growth factor (EGF), platelet-derived growth factor (PDGF), insulin, thrombin, and the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA)). Enter, the Ras/Raf/MEK/ERK cascade via different growth factors receptors

Increased water intake decreases progression of polycystic kidney disease in the PCK rat.

Renal enlargement in polycystic kidney disease (PKD) is caused by the proliferation of mural epithelial cells and transepithelial fluid secretion into the cavities of innumerable cysts. Arginine vasopressin (AVP) stimulates the proliferation of human PKD cells in vitro via cAMP-dependent activation of the B-Raf/MEK (MAPK/ERK kinase/extracellular signal-regulated kinase (ERK) pathway. ERK activity is elevated in cells that line the cysts in animals with PKD, and AVP receptor antagonists reduce ERK activity and halt disease progression. For suppression of the effect of AVP physiologically, water

Craf-1 protein kinase is essential for mouse development.

The three mammalian Raf serine/threonine protein kinases mediate the transduction of proliferative and differentiative signals from a variety of cell surface receptors to the nucleus. We report here that Craf-1 is essential for mouse development, as its mutation results in embryonic lethality. Developmental defects are found in mutant placentas as well as in the skin and in the lungs of mutant embryos. Craf-1 mutants also display a generalized growth retardation which is consistent with the ubiquitous expression of Craf-1 and which could be due to the reduced proliferation of mutant cells. Int

Computational-experimental repurposing reveals synergistic sorafenib/hydroxychloroquine response in KRAS-mutant breast cancer.

BACKGROUND: KRAS mutations are approximately 25% of human cancers, with particularly high incidence in breast and lung cancers, by constitutively triggering MAPK/ERK and PI3K/AKT pathways that advance proliferation, survival, and autophagy-mediated resistance. Targeting these pathways with kinase inhibitors upregulates autophagy, thereby diminishing therapeutic efficacy. Thus, combining kinase inhibitors with autophagy inhibitors offers a rational strategy to enhance antitumor benefits in KRAS-mutant malignancies. FDA-approved Sorafenib (multi-kinase inhibitor targeting Raf) and Hydroxychloroq

Inhibition of tumor angiogenesis by the matrix metalloproteinase-activated anthrax lethal toxin in an orthotopic model of anaplastic thyroid carcinoma.

Patients with anaplastic thyroid carcinoma (ATC) typically succumb to their disease months after diagnosis despite aggressive therapy. A large percentage of ATCs have been shown to harbor the V600E B-Raf point mutation, leading to the constitutive activation of the mitogen-activated protein kinase pathway. ATC invasion, metastasis, and angiogenesis are in part dependent on the gelatinase class of matrix metalloproteinases (MMP). The explicit targeting of these two tumor markers may provide a novel therapeutic strategy for the treatment of ATC. The MMP-activated anthrax lethal toxin (LeTx), a n

The role of tuberin in cellular differentiation: are B-Raf and MAPK involved?

Tuberous sclerosis complex (TSC) is a tumor suppressor gene syndrome whose manifestations can include seizures, mental retardation, autism, and tumors in the brain, retina, kidney, heart, and skin. The products of the TSC1 and TSC2 genes, hamartin and tuberin, respectively, heterodimerize and inhibit the mammalian target of rapamycin (mTOR). This review focuses on the genetic and biochemical basis of the renal and pulmonary manifestations of TSC, angiomyolipomas, and lymphangiomyomatosis, respectively. Genetic analyses of sporadic angiomyolipomas revealed that all three components (smooth musc

Activity of sorafenib in recurrent ovarian cancer and primary peritoneal carcinomatosis: a gynecologic oncology group trial.

PURPOSE Sorafenib is a kinase inhibitor targeting Raf and other kinases (ie, vascular endothelial growth factor receptor [VEGFR], platelet-derived growth factor receptor [PDGFR], Flt3, and c-KIT). This study assessed its activity and tolerability in patients with recurrent ovarian cancer (OC) or primary peritoneal carcinomatosis (PPC). METHODS This open-label, multi-institutional, phase II study used a two-stage design. Eligible patients had persistent or recurrent OC/PPC after one to two prior cytotoxic regimens, and they experienced progression within 12 months of platinum-based therapy. Tre

Current and Emerging Therapies for Targeting the ERK1/2 & PI3K Pathways in Cancer.

The ERK1/2 and PI3K signaling pathways play important roles in cellular proliferation, survival, differentiation, and metabolism. In cancer, these pathways are frequently dysregulated and overactivated, resulting in poor patient prognosis and resistance to treatment. These pathways are activated by receptor tyrosine kinases and send downstream signals to effectors such as RAS, RAF, MEK, AKT, and mTOR. In this review, we highlight the key components of the ERK1/2 and PI3K pathways, the roles they play in tumor progression, and the development of inhibitors and combination therapies designed to

The X-linked juvenile retinoschisis protein retinoschisin is a novel regulator of mitogen-activated protein kinase signalling and apoptosis in the retina.

X-linked juvenile retinoschisis (XLRS) is a hereditary retinal dystrophy in young males, caused by mutations in the RS1 gene. The function of the encoded protein, termed retinoschisin, and the molecular mechanisms underlying XLRS pathogenesis are still unresolved, although a direct interaction partner of the secreted retinoschisin, the retinal Na/K-ATPase, was recently identified. Earlier gene expression studies in retinoschisin-deficient (Rs1h-/Y ) mice provided a first indication of pathological up-regulation of mitogen-activated protein (MAP) kinase signalling in disease pathogenesis. To fu

Raf-1 provides a dominant but not exclusive signal for the induction of CD69 expression on T cells.

Stimulation of the T cell antigen receptor (TCR) induces a number of intracellular signaling pathways which lead to the transcription of a variety of new genes. Of the newly synthesized proteins, the earliest to be detected on the cell surface is the type II integral membrane protein CD69. Cross-linking of this activation antigen induces signaling events related to T cell activation. The proto-oncogene product Ras has been reported to up-regulate CD69. However, which of the potential effectors of Ras induces the expression of CD69 has remained unclear. Using transient transfection, we have sho

Onco-immunomodulatory properties of pharmacological interference with RAS-RAF-MEK-ERK pathway hyperactivation.

Hyperactivation of the RAS-RAF-MEK-ERK cascade - a mitogen-activated protein kinase pathway - has a well-known association with oncogenesis of leading tumor entities, including non-small cell lung cancer, colorectal carcinoma, pancreatic ductal adenocarcinoma, and malignant melanoma. Increasing evidence shows that genetic alterations leading to RAS-RAF-MEK-ERK pathway hyperactivation mediate contact- and soluble-dependent crosstalk between tumor, tumor microenvironment (TME) and the immune system resulting in immune escape mechanisms and establishment of a tumor-sustaining environment. Consequ

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… The MAPKKs themselves are activated by different MAPKKKs, most importantly the group of RAF kinases, which are in turn activated by various upstream signals ( 31 ). …

Whole-Exome Sequencing Identifies Novel Heterozygous Mutation in RAF1 in Family With Neonatal Testicular Torsion.

OBJECTIVE: To investigate a genetic cause of neonatal testicular torsion in 2 siblings and paternal cryptorchidism in a Caucasian family without history of consanguinity, we performed whole exome sequencing. PATIENTS AND METHODS: Targeted exon/whole-exome sequencing was performed in 2 siblings with testicular torsion. Potentially pathogenic variants passing filter criteria were validated with Sanger sequencing of parents to confirm familial segregation. Additionally, immunofluorescence staining for Raf-1, pERK (downstream from Raf-1) and c-Kit was performed on a testicular biopsy on the prese

Targeting the PI3K/Akt pathway in murine MDS/MPN driven by hyperactive Ras.

Chronic and juvenile myelomonocytic leukemias (CMML and JMML) are myelodysplastic/myeloproliferative neoplasia (MDS/MPN) overlap syndromes that respond poorly to conventional treatments. Aberrant Ras activation because of NRAS, KRAS, PTPN11, CBL and NF1 mutations is common in CMML and JMML. However, no mechanism-based treatments currently exist for cancers with any of these mutations. An alternative therapeutic strategy involves targeting Ras-regulated effector pathways that are aberrantly activated in CMML and JMML, which include the Raf/MEK/ERK and phosphoinositide-3'-OH kinase (PI3K)/Akt ca

Enhanced Killing of Colon Cancer Cells by Mesoporous Silica Nanoparticles Loaded with Ellagic Acid.

BACKGROUND: Natural compounds, including ellagic acid (ELG), are promising anticancer agents with low adverse effects. In this paper, we test in vitro the effectiveness of mesoporous silica nanoparticles (MSN) as an ELG carrier against colon cancer. METHODS: We produced MSNs functionalized with triptycene (TRP) and loaded with ELG, further called MSNTRPELG nanoformulation. The nanoformulation contained over 11 wt.% TRP and approximately 25 wt.% ELG in the mesoporous structure and on the surface of particles. It was assessed for anticancer effects against two colon cancer cells: HCT-116 and HT

PP2 protects from keratin mutation-associated liver injury and filament disruption via SRC kinase inhibition in male but not female mice.

BACKGROUND AND AIMS: Hepatocyte keratin polypeptides 8/18 (K8/K18) are unique among intermediate filaments proteins (IFs) in that their mutation predisposes to, rather than causes, human disease. Mice that overexpress human K18 R90C manifest disrupted hepatocyte keratin filaments with hyperphosphorylated keratins and predisposition to Fas-induced liver injury. We hypothesized that high-throughput screening will identify compounds that protect the liver from mutation-triggered predisposition to injury. APPROACH AND RESULTS: Using A549 cells transduced with a lentivirus K18 construct and high-t

[Treatment of patients with brain metastases from a melanoma].

Whereas immune checkpoint inhibitors of serine/threonine protein kinase B-raf therapy dramatically changed metastatic outcomes of patients with melanoma, they remain at high risk of brain extension. Additional local treatment can be offered in this situation such as surgery and or stereotactic radiotherapy. In this review article, we describe the different options with published data and their optimal timing.

FAK inhibitor and RAF/MEK clamp avutometinib enhance KRAS G12C inhibitor efficacy in preclinical models of non-small cell lung cancer.

KRAS G12C (Gly12→Cys) inhibitors (G12Cis) have improved outcomes for patients with KRAS G12C-mutated non-small cell lung cancer (NSCLC), but their clinical benefit is limited by the emergence of resistance mechanisms. Here, we demonstrate that combining the RAF/MEK clamp avutometinib and the focal adhesion kinase (FAK) inhibitor defactinib with a G12Ci enhanced antitumor activity by deepening mitogen-activated protein kinase (MAPK) pathway suppression and simultaneously inhibiting adaptive resistance pathways induced by G12Ci and avutometinib treatment, including FAK and PI3K signaling. In KRA

Relations between the mitogen-activated protein kinase and the cAMP-dependent protein kinase pathways: comradeship and hostility.

Inter- and intracellular communications and responses to environmental changes are pivotal for the orchestrated and harmonious operation of multi-cellular organisms. These well-tuned functions in living organisms are mediated by the action of signal transduction pathways, which are responsible for receiving a signal, transmitting and amplifying it, and eliciting the appropriate cellular responses. Mammalian cells posses numerous signal transduction pathways that, rather than acting in solitude, interconnect with each other, a phenomenon referred to as cross-talk. This allows cells to regulate