Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melanoma incidence is increasing worldwide, and metastatic melanoma is almost completely resistant to every known therapy. New approaches to treating melanoma are urgently needed, and a greater understanding of the biology of melanoma invasion and metastasis will aid in their creation. A high proportion of invasive melanomas have a constitutively active Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) signaling cascade; however, the downstream effectors of ERK signaling that contribute to melanoma invasion and metastasis are unknown. ERK signaling drives the production of the interstitial collagenase matrix metalloproteinase-1 (MMP-1), which is expressed specifically by invasive melanomas. Using short hairpin RNAs (shRNA) to knock down MMP-1 expression in a human melanoma cell line, we investigated the role of MMP-1 in melanoma metastasis in a xenograft model. Knockdown of MMP-1 had no effect on primary tumor growth, but reduction of MMP-1 expression significantly decreased the ability of the melanoma to metastasize from the orthotopic site in the dermis to the lung. Mechanistically, tumor cells expressing MMP-1 shRNAs had diminished collagenase activity, which is required for tumor cell invasion. Additionally, attenuation of MMP-1 expression reduced angiogenesis. These results show, for the first time, that targeted inhibition of MMP-1, a single effector of the Raf/MEK/ERK signaling cascade, prevents the progression of melanoma from a primary to metastatic tumor and, as such, may represent a useful therapeutic tool in controlling this disease.
 ...
PMID:RNA interference inhibition of matrix metalloproteinase-1 prevents melanoma metastasis by reducing tumor collagenase activity and angiogenesis. 1800 30

Malignant melanoma originates in melanocytes, the pigment-producing cells of the skin and eye, and is one of the most deadly human cancers with no effective cure for metastatic disease. Like many other cancers, melanoma has both environmental and genetic components. For more than 20 years, the melanoma genome has been subject to extensive scrutiny, which has led to the identification of several genes that contribute to melanoma genesis and progression. Three molecular pathways have been found to be nearly invariably dysregulated in melanocytic tumors, including the RAS-RAF-MEK-ERK pathway (through mutation of BRAF, NRAS or KIT), the p16 INK4A-CDK4-RB pathway (through mutation of INK4A or CDK4) and the ARF-p53 pathway (through mutation of ARF or TP53). Less frequently targeted pathways include the PI3K-AKT pathway (through mutation of NRAS, PTEN or PIK3CA) and the canonical Wnt signaling pathway (through mutation of CTNNB1 or APC). Beyond the specific and well-characterized genetic events leading to activation of proto-oncogenes or inactivation of tumor suppressor genes in these pathways, systematic high-resolution genomic analysis of melanoma specimens has revealed recurrent DNA copy number aberrations as well as perturbations of DNA methylation patterns. Melanoma provides one of the best examples of how genomic analysis can lead to a better understanding of tumor biology. We review current knowledge of the genes involved in the development of melanoma and the molecular pathways in which these genes operate.
 ...
PMID:The genome and epigenome of malignant melanoma. 1804 49

Angiogenesis, the process of new blood vessel formation, is important in wound healing, inflammation, tumorigenesis and metastases. During this process, it is a critical step of the loosening of cellular interactions between endothelial cells, which are dependent on the architecture of adherens junction constructed by homophilic interactions of cell surface cadherins. Several studies suggested that the dynamic changes of cadherins are necessary during angiogenesis. However, the mechanism of cadherins regulation on endothelial cells requires further delineation. Here, we showed that basic fibroblast growth factor (bFGF), a pivotal pro-angiogenic factor, can downregulate typical cadherins (E-, N-, P- and VE-cadherin) expression on the surface of human umbilical vein endothelial cells (HUVECs) via FGF receptor 1 (FGFR1) signaling. The bFGF-mediated surface cadherin downregulation was significantly reversed only when the HUVECs were treated with JNK inhibitor (SP600125), but not ERK (PD98059) or p38 inhibitor (SB203580). Infecting HUVECs with a dominant negative H-Ras mutant (Ras(S17N)) interferes bFGF-mediated cadherin downregulation, and the result suggests that bFGF attenuates surface cadherin expression on HUVECs via FGFR1 and intracellular Ras-JNK signaling. However, after growth factors withdrawal, FGFR1 blockade or JNK inhibition for 16 h, cadherins were re-expressed on cell surface of HUVECs. But the mRNA or total protein of cadherins had no significant change, suggesting that the effect of bFGF on cadherin expression may work through a post-translational control. Our data first suggest that JNK participates in bFGF-mediated surface cadherin downregulation. Loss of surface cadherins may affect the cell-cell interaction between endothelial cells and facilitate angiogenesis.
 ...
PMID:JNK signaling pathway is required for bFGF-mediated surface cadherin downregulation on HUVEC. 1816 4

Systemic chemotherapy has limited success in treating liver metastasis of colorectal cancer. Alternative approaches such as hepatic arterial infusion or trans arterial chemoembolisation aim to deliver the chemotherapy locally to address the predominant liver disease. Chemoembolisation with drug eluting beads (DEB) designed to deliver drug at the target over a protracted period of time is a new strategy to reduce the tumor burden of liver metastases. To test this hypothesis, DEB possessing anionic groups capable of ionically complexing with cationic drugs were synthesised by a suspension polymerisation method and were fractionated to produce an average size of 75 microm. The DEB were loaded with the desired concentration of either doxorubicin hydrochloride or irinotecan hydrochloride prior to administration by immersion in the drug solution, yielding essentially 100% loading efficiency. To determine their effect in vivo, a transplantable orthotopic and isogenic rat liver metastasis model was used which is based on intraportal injection of 4 x 10(6) beta-galactosidase transfected CC531 rat colorectal cancer cells into male WAG/Rij rats. By MTT assay, the cells were shown to be sensitive to both drugs in vitro with the IC(50) being by two orders of magnitude lower for doxorubicin (110 nM after 72 h) compared to irinotecan (25 microM after 72 h). For the in vivo phase, a differential expression of the ERK MAP kinase between tumor cells cultured in vitro and those inoculated in vivo was noted using Western blotting techniques. This was considered to be indicative of passage-induced cell senescence that reduced the sensitivity of the tumor cells to DEB chemoembolisation. This notwithstanding, administration of DEB loaded with irinotecan or doxorubicin by single injection into the hepatic artery showed significant anticancer activity, as measured by a reduction in the tumor burden of the liver and a corresponding reduction in liver weight. Comparing the two agents, irinotecan appears more advantageous because of its significant activity and excellent tolerability following administration at two dosages of either 20 or 30 mg/kg. Doxorubicin showed a narrower window of activity, being effective at 4 mg/kg but ineffective at the lower dose of 2 mg/kg. We conclude that chemoembolisation with DEB with either agent may have potential for treating patients with colorectal liver metastasis, although irinotecan DEB appeared to have a more favourable safety profile.
Clin Exp Metastasis 2008
PMID:Chemoembolisation of rat colorectal liver metastases with drug eluting beads loaded with irinotecan or doxorubicin. 1825 82

There are ten mitogen-activated protein kinase (MAPK) phosphatases (MKPs) that act as negative regulators of MAPK activity in mammalian cells and these can be subdivided into three groups. The first comprises DUSP1/MKP-1, DUSP2/PAC1, DUSP4/MKP-2 and DUSP5/hVH-3, which are inducible nuclear phosphatases. With the exception of DUSP5, these MKPs display a rather broad specificity for inactivation of the ERK, p38 and JNK MAP kinases. The second group contains three closely related ERK-specific and cytoplasmic MKPs encoded by DUSP6/MKP-3, DUSP7/MKP-X and DUSP9/MKP-4. The final group consists of three MKPs DUSP8/hVH-5, DUSP10/MKP-5 and DUSP16/MKP-7 all of which preferentially inactivate the stress-activated p38 and JNK MAP kinases. Abnormal MAPK signalling will have important consequences for processes critical to the development and progression of human cancer. In addition, MAPK signalling also plays a key role in determining the response of tumour cells to conventional cancer therapies. The emerging roles of the dual-specificity MKPs in the regulation of MAPK activities in normal tissues has highlighted the possible pathophysiological consequences of either loss (or gain) of function of these enzymes as part of the oncogenic process. This review summarises the current evidence implicating the dual-specificity MKPs in the initiation and development of cancer and also on the outcome of treatment.
Cancer Metastasis Rev 2008 Jun
PMID:Dual-specificity MAP kinase phosphatases (MKPs) and cancer. 1833 Jun 78

NSCLC cells with a mesenchymal phenotype have shown a marked reduction in sensitivity to EGFR inhibitors, though the molecular rationale has remained obscure. Here we find that in mesenchymal-like tumor cells both tyrosine phosphorylation of EGFR, ErbB2, and ErbB3 signaling networks and expression of EGFR family ligands were decreased. While chronic activation of EGFR can promote an EMT-like transition, once having occurred EGFR family signaling was attenuated. We investigated the mechanisms by which mesenchymal-like cells bypass EGFR signaling and acquire alternative routes of proliferative and survival signaling. Mesenchymal-like NSCLC cells exhibit aberrant PDGFR and FGFR expression and autocrine signaling through these receptors can activate the MEK-ERK and PI3K pathways. Selective pharmacological inhibition of PDGFR or FGFR receptor tyrosine kinases reduced cell proliferation in mesenchymal-like but not epithelial NSCLC cell lines. A metastable, reversible EMT-like transition in the NSCLC line H358 was achieved by exogenous TGFbeta, which served as a model EMT system. The H358/TGFbeta cells showed many of the attributes of established mesenchymal-like NSCLC cells including a loss of cell-cell junctions, a loss of EGF-family ligand expression, a loss of ErbB3 expression, increased EGFR-independent Mek-Erk pathway activation and reduced sensitivity to EGFR inhibition. Notably an EMT-dependent acquisition of PDGFR, FGFR and TGFbeta receptors in H358/TGFbeta cells was also observed. In H358/TGFbeta cells both PDGFR and FGFR showed functional ligand stimulation of their intrinsic tyrosine kinase activities. The findings of kinase switching and acquired PDGFR and FGFR signaling suggest investigation of new inhibitor combinations to target NSCLC metastases.
Clin Exp Metastasis 2008
PMID:Kinase switching in mesenchymal-like non-small cell lung cancer lines contributes to EGFR inhibitor resistance through pathway redundancy. 1869 32

Interaction between the chemokine CXCL12 (SDF1) and the G-protein coupled receptor CXCR4 is responsible for the maintenance of adult stem cell niches and is known to play an important role in utero in the migration of primordial germ cells. We demonstrate expression of CXCL12 by Sertoli cells and confirm CXCR4 expression by the germ cell population of the adult human testes. CXCR4 is also known to mediate organ-specific patterns of metastases in a range of common cancers. We identify consistent expression of CXCR4 mRNA and protein in testicular germ cell tumours (TGCT) that accounts for their patterns of relapse in sites of known CXCL12 expression. Extragonadal primary germ cell tumours express CXCR4 and their sites of occurrence are coincident with areas of known CXCL12 expression in utero. We show that CXCL12 stimulates the invasive migration of a TGCT cell line in vitro in a CXCR4-dependent fashion and activates ERK. Furthermore, we demonstrate that expression of CXCL12 in stage I non-seminomas is significantly associated with organ-confined disease post-orchidectomy and reduced risk of relapse (p = 0.003). This may be through the loss of CXCL12 gradients that might otherwise attract cells away from the primary tumour. We propose CXCL12 expression as a potential predictor of subsequent relapse that could lead to avoiding unnecessary treatment and associated late toxicities. Our observations support a role for CXCL12/CXCR4 in the adult germ cell population and demonstrate pathological function in germ cell tumour development and metastasis that may have clinical utility.
 ...
PMID:Clinical and biological significance of CXCL12 and CXCR4 expression in adult testes and germ cell tumours of adults and adolescents. 1883 94

Metastasis of breast cancer cells is the leading cause of death in breast cancer patients. Why do breast cancer cells with high metastatic potential always keep in high proliferation and migration? The endogenous signaling pathways associated with tumor metastasis remain unclear. In the present study, we address whether a link between ERK and the enzymes associated with arachidonic acid (AA) metabolism contributes to the proliferation and migration of breast cancer cells. To identify endogenous signaling pathways involved in sustaining proliferation and migration of breast cancer cells, we performed parallel studies of human breast cancer cell lines that differ in their metastatic potential. Our data showed that cell lines with high metastatic potential, including LM-MCF-7 and MDA-MB-231, exhibited significantly high, sustained levels of phosphorylated ERK (pERK) 1/2 relative to MCF-7 cells. Our findings showed that beta-catenin, cyclin D1, and survivin serve downstream effectors of pERK1/2, whereas Gi/o proteins, phospholipase C, and protein kinase C serve upstream activators of pERK1/2. In addition, AA metabolites were able to activate Gi/o proteins, phospholipase C, protein kinase C, and pERK1/2 cascades through cyclooxygenase and lipoxygenase. In contrast, activated ERK1/2 promoted AA metabolism through a positive feedback loop, which conduces to a high proliferative potential and the migration of the breast cancer cells. Together, our data provide new mechanistic insights into possible endogenous signaling metastatic signaling pathways involved in maintaining proliferation and migration of breast cancer cells.
 ...
PMID:A positive feedback between activated extracellularly regulated kinase and cyclooxygenase/lipoxygenase maintains proliferation and migration of breast cancer cells. 1900 12

Metastasis is the principal cause of death from breast cancer. ErbB2 (HER-2/neu) has been identified as an important regulator of metastatic potential of breast cancer. The present study investigated the molecular mechanism underlying the role of ErbB2 in malignant phenotypic conversion of MCF10A human breast epithelial cells which originally have 'normal' cell character. Here we report that ErbB2 induces invasion and migration of MCF10A cells though up-regulation of matrix metalloproteinase (MMP)-9. We also observed a marked reduction of an epithelial cell marker, E-cadherin, and an induction of vimentin in ErbB2-MCF10A cells, suggesting that epithelial-mesenchymal transition may play a role in the ErbB2-induced invasion and migration of MCF10A cells. Overexpression of ErbB2 significantly activated p38 MAPK and Akt, while Raf-1/MEK/ERK pathway was not activated by ErbB2. Using pharmacological inhibitors, we further show that p38 MAPK and Akt signaling pathways are crucial for the ErbB2-induced MMP-9 up-regulation, invasion and migration of MCF10A cells. Given that ErbB2 is one of the most important oncogenes in human breast cancer and thus is an attractive therapeutic target, our findings may provide a molecular basis for the promoting role of ErbB2 in breast cancer progression.
 ...
PMID:Overexpression of ErbB2 induces invasion of MCF10A human breast epithelial cells via MMP-9. 1902 65

Src family kinases (SFKs) have a critical role in cell adhesion, invasion, proliferation, survival, and angiogenesis during tumor development. SFKs comprise nine family members that share similar structure and function. Overexpression or high activation of SFKs occurs frequently in tumor tissues and they are central mediators in multiple signaling pathways that are important in oncogenesis. SFKs can interact with tyrosine kinase receptors, such as EGFR and the VEGF receptor. SFKs can affect cell proliferation via the Ras/ERK/MAPK pathway and can regulate gene expression via transcription factors such as STAT molecules. SFKs can also affect cell adhesion and migration via interaction with integrins, actins, GTPase-activating proteins, scaffold proteins, such as p130(CAS) and paxillin, and kinases such as focal adhesion kinases. Furthermore, SFKs can regulate angiogenesis via gene expression of angiogenic growth factors, such as fibroblast growth factor, VEGF, and interleukin 8. On the basis of these important findings, small-molecule SFK inhibitors have been developed and are undergoing early phase clinical testing. In preclinical studies these agents can suppress tumor growth and metastases. The agents seem to be safe in humans and could add to the therapeutic arsenal against subsets of cancers.
 ...
PMID:Src kinases as therapeutic targets for cancer. 1978 2


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>