Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor survival, growth and metastasis depend on efficient tumor cell proliferation and tumor angiogenesis, and targeting both of these processes simultaneously could prove to be therapeutically relevant. The RAS/RAF signaling pathway is an important mediator of tumor cell proliferation, and angiogenesis and is often aberrantly activated in human tumors due to the presence of activated Ras or mutant B-Raf, or elevation of growth factor receptors. Sorafenib, which belongs chemically to a class that can be described as bis-aryl ureas, was selected for further pharmacologic characterization based on potent inhibition of Raf-1 and its favorable kinase selectivity profile. Further characterization showed that sorafenib suppresses both wild-type and V599E mutant B-Raf activity in vitro. In addition, sorafenib demonstrated significant activity against several receptor tyrosine kinases involved in neovascularization and tumor progression, including vascular-endothelial growth factor (VEGFR)-2, VEGFR-3, platelet-derived growth factor (PDGFR)-beta Flt-3, and c-KIT. Preclinically, sorafenib showed broad-spectrum antitumor activity in colon, breast and non-small-cell lung cancer xenograft models. A total of four phase I studies using oral sorafenib as a single agent have been completed, and the compound showed a favorable safety profile with mild to moderate diarrhea being the most common treatment-related adverse event. The maximum tolerated dose was 400 mg b.i.d. continuous. Single-agent phase II trials reported so far demonstrated antitumor activity of sorafenib in patients with hepatocellular carcinoma, sarcoma and renal cell cancer (RCC). Based on phase II results in RCC patients, a placebo-controlled phase III study was performed, which randomized a total of 905 patients, most of whom were treated previously. The partial response rate was 2% for sorafenib and 0% for placebo. Stable disease was observed in 78% and 55% of patients on sorafenib and placebo, respectively. Sorafenib significantly prolonged median progression-free survival (24 weeks) compared with placebo (12 weeks) in all subsets of patients evaluated. Approval of sorafenib by the U.S. Food and Drug Administration for this indication is pending. A first-line phase III study in RCC as well as phase III studies in hepatocellular carcinoma and metastatic melanoma have been initiated.
 ...
PMID:Preclinical and clinical development of the oral multikinase inhibitor sorafenib in cancer treatment. 1647 53

Because a variety of receptor tyrosine kinases are involved in the mechanism of tumor progression, the development of a clinically useful tyrosine kinase inhibitor is expected as a therapeutic agent for the treatment of malignant cancers. Imatinib mesylate, known as Gleevec or STI-571, is a molecule that inhibits the function of various receptors with tyrosine kinase activity, such as Abl, the bcr-abl chimeric product, KIT, and platelet-derived growth factor (PDGF) receptors. In this study, we investigated the influence of dosing time on the ability of imatinib to inhibit tumor growth in mice. Tumor-bearing mice were housed under standardized light/dark cycle conditions (lights on at 07:00 h, off at 19:00 h) with food and water ad libitum. The growth of tumor cells implanted in mice was more severely inhibited by the administration of imatinib (50 mg/kg, i.p.) in the early light phase than when it was administered in the early dark phase. The dosing time-dependency of anti-tumor effects was parallel to that of imatinib-induced anti-angiogenic effect. The inhibitory effect of imatinib on tyrosine kinase activity of PDGF receptors, but not of KIT and Abl, varied according to its administration time. The dosing time-dependency of imatinib-induced inhibition of PDGF receptor activity was closely related to that of its anti-tumor effects. Our results suggest that the anti-tumor efficacy of imatinib is enhanced by administering the drug when PDGF receptor activity was increased. The potent therapeutic efficacy of the drug could be expected by optimizing the dosing schedule.
 ...
PMID:Basis for dosing time-dependent change in the anti-tumor effect of imatinib in mice. 1697 34

Molecular modeling studies led to the identification of LFM-A13 (alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)propenamide) as a potent inhibitor of Polo-like kinase (Plk). LFM-A13 inhibited recombinant purified Plx1, the Xenopus homolog of Plk, in a concentration-dependent fashion, as measured by autophosphorylation and phosphorylation of a substrate Cdc25 peptide. LFM-A13 was a selective Plk inhibitor. While the human PLK3 kinase was also inhibited by LFM-A13 with an IC(50) value of 61 microM, none of the 7 other serine/threonine kinases, including CDK1, CDK2, CDK3, CHK1, IKK, MAPK1 or SAPK2a, none of the 10 tyrosine kinases, including ABL, BRK, BMX, c-KIT, FYN, IGF1R, PDGFR, JAK2, MET, or YES, or the lipid kinase PI3Kgamma were inhibited (IC(50) values >200-500 microM). The mode of Plk3 inhibition by LFM-A13 was competitive with respect to ATP with a K(i) value of 7.2 microM from Dixon plots. LFM-A13 blocked the cell division in a zebrafish (ZF) embryo model at the 16-cell stage of the embryonic development followed by total cell fusion and lysis. LFM-A13 prevented bipolar mitotic spindle assembly in human breast cancer cells and glioblastoma cells and when microinjected into living epithelial cells at the prometaphase stage of cell division, it caused a total mitotic arrest. Notably, LFM-A13-delayed tumor progression in the MMTV/neu transgenic mouse model of HER2 positive breast cancer at least as effectively as paclitaxel and gemcitabine. LFM-A13 showed a favorable toxicity profile in mice and rats. In particular there was no evidence of hematologic toxicity as documented by peripheral blood counts and bone marrow examinations. These results establish LFM-A13 as a small molecule inhibitor of Plk with in vitro and in vivo anti-proliferative activity against human breast cancer.
 ...
PMID:Anti-breast cancer activity of LFM-A13, a potent inhibitor of Polo-like kinase (PLK). 1709 32

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs range from benign indolent neoplasms to highly malignant sarcomas. Gain-of-function mutations of tyrosine kinase receptors, KIT or PDGFRA, have been identified in most GISTs. In this study, we report 36 GIST patients whose tumors had homozygous KIT exon 11 mutations detected by direct sequencing of PCR products. Loss of heterozygosity in KIT locus and other chromosome 4 loci were documented in majority of these tumors. However, fluorescence in situ hybridization with KIT locus-specific probe and chromosome 4 centromeric enumeration probe showed no evidence of KIT hemizygosity in a majority of analyzed cases. These findings are consistent with duplication of chromosome 4 with KIT mutant allele. Homozygous KIT exon 11 mutations were found in 33 primary tumors and 7 metastatic lesions. In two cases, shift from heterozygosity to homozygosity was documented during tumor progression being present in metastases, but not in primary tumors. Among primary GISTs, there were 16 gastric, 18 intestinal and 2 from unknown locations. An average primary tumor size was 12 cm and average mitotic activity 32/50 HPFs. Out of 32 tumors 29 (90.6%) with complete clinicopathologic data were diagnosed as sarcomas with more than 50% risk of metastatic disease, and 26 of 29 patients with follow-up had metastases or died of disease. An average survival time among pre-imatinib patients, who died of the disease was 33.4 months. Based on these findings, we conclude that presence of homozygous KIT exon 11 mutations is associated with malignant course of disease and should be considered an adverse prognostic marker in GISTs.
 ...
PMID:Presence of homozygous KIT exon 11 mutations is strongly associated with malignant clinical behavior in gastrointestinal stromal tumors. 1843 12

Overcoming intrinsic and acquired resistance of cancer stem/progenitor cells to current clinical treatments represents a major challenge in treating and curing the most aggressive and metastatic cancers. This review summarizes recent advances in our understanding of the cellular origin and molecular mechanisms at the basis of cancer initiation and progression as well as the heterogeneity of cancers arising from the malignant transformation of adult stem/progenitor cells. We describe the critical functions provided by several growth factor cascades, including epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), stem cell factor (SCF) receptor (KIT), hedgehog and Wnt/beta-catenin signalling pathways that are frequently activated in cancer progenitor cells and are involved in their sustained growth, survival, invasion and drug resistance. Of therapeutic interest, we also discuss recent progress in the development of new drug combinations to treat the highly aggressive and metastatic cancers including refractory/relapsed leukaemias, melanoma and head and neck, brain, lung, breast, ovary, prostate, pancreas and gastrointestinal cancers which remain incurable in the clinics. The emphasis is on new therapeutic strategies consisting of molecular targeting of distinct oncogenic signalling elements activated in the cancer progenitor cells and their local microenvironment during cancer progression. These new targeted therapies should improve the efficacy of current therapeutic treatments against aggressive cancers, and thereby preventing disease relapse and enhancing patient survival.
 ...
PMID:Recent advances in cancer stem/progenitor cell research: therapeutic implications for overcoming resistance to the most aggressive cancers. 1797 79

Gastrointestinal stromal tumors (GISTs) are the most common nonepithelial neoplasm of the gastrointestinal tract and show a predilection for the stomach. Most are detected because of symptoms, but some are incidental findings at autopsy or surgery for other reasons. Incidental GISTs tend to be smaller at diagnosis, but even small (<1 cm) GISTs have been shown to harbor activating KIT mutations at rates similar to advanced GISTs. However, the prevalence and characteristics of small GISTs in surgical resections of the esophagogastric junction (EGJ) remains unclear. We studied 150 esophagogastric resections for esophageal or EGJ carcinomas (100 with preoperative chemoradiation and 50 untreated cases) that had been extensively embedded for histologic examination (mean 30 sections/case). Number, size, morphology, and location of all GISTs and leiomyomas were recorded. All potential GISTs were evaluated with CD117 and CD34 immunohistochemistry, and a subset (35) leiomyomas with smooth muscle actin, desmin, and CD117. We found 18 incidental GISTs in 15 of 150 (10%) patients; 3 patients harbored 2 separate lesions. Prevalence of GIST was identical in treated (10 of 100) and untreated (5 of 50) cases. All (100%) showed positivity for both CD117 and CD34 and all were of spindle cell morphology. Lesions ranged from 0.2 to 3.0 mm in size (mean 1.3 mm). Eight (44%) were based in the outer muscularis propria, 7 (39%) in inner muscularis, and 3 (17%) between the muscle layers. The lesions tended to cluster near the EGJ, with 8 (44%) on the gastric side, 9 (50%) on the esophageal side, and 1 (6%) undetermined owing to overlying ulceration. Leiomyomas were even more common than GIST, occurring in 47% of patients (44% of treated and 52% of untreated, P=0.39), with a mean of 3 leiomyomas per patient (range 1 to 13) and mean size of 1.7 mm (range 0.2 to 12 mm). Unlike colorectal leiomyomas, most (91%) EGJ leiomyomas were located in the inner muscularis propria and only rarely (1%) in muscularis mucosa. These results suggest that GIST and leiomyoma are common incidental "seedling" lesions of the EGJ, found in 10% and 47% of patients undergoing surgery for esophageal carcinoma. The common occurrence of microscopic GISTs compared with the rarity of clinically manifest and malignant esophagogastric GISTs suggests that additional genetic or epigenetic alterations must happen for neoplastic progression.
 ...
PMID:"Seedling" mesenchymal tumors (gastrointestinal stromal tumors and leiomyomas) are common incidental tumors of the esophagogastric junction. 1805 18

Activating mutation in KIT or platelet-derived growth factor-alpha can lead to gastrointestinal stromal tumors (GISTs). Eighty-four cases from two institutes were analyzed. Of them, 62 (74%) harbored KIT mutations, 7 of which are previously unreported. One exhibited duplication from both intron 11 and exon 11, which has not been reported in KIT in human cancer. A homozygous/hemizygous KIT-activating mutation was found in 9 of the 62 cases (15%). We identified three GIST patients with heterozygous KIT-activating mutations at initial presentation, who later recurred with highly aggressive clinical courses. Molecular analysis at recurrence showed total dominance of homozygous (diploid) KIT-activating mutation within a short period of 6-13 months, suggesting an important role of oncogene homozygosity in tumor progression. Topoisomerase II is active in the S- and G(2) phases of cell cycle and is a direct and accurate proliferative indicator. Cellular and molecular analysis of serial tumor specimens obtained from consecutive surgeries or biopsy within the same patient revealed that these clones that acquired the homozygous KIT mutation exhibited an increased mitotic count and a striking fourfold increase in topoisomerase II proliferative index (percentage cells show positive topoisomerase II nuclear staining compared to the heterozygous counterpart within the same patient. KIT forms a homodimer as the initial step in signal transduction and this may account for the quadruple increase in proliferation. Using SNPs for allelotyping on the serial tumor specimens, we demonstrate that the mechanism of the second hit resulting in homozygous KIT-activating mutation and loss of heterozygosity is achieved by mitotic nondisjunction, contrary to the commonly reported mechanism of mitotic recombination.
 ...
PMID:Evolution from heterozygous to homozygous KIT mutation in gastrointestinal stromal tumor correlates with the mechanism of mitotic nondisjunction and significant tumor progression. 1848

Advances in the field of GIST accumulate very rapidly. The objective of this short review is to underline their consequences for the diagnostic practice and for the understanding of their pathogenesis. The diagnosis of GIST still relies on histology and immunohistochemistry; this is only in the case of the very rare KIT-negative tumors that other markers (such as DOG-1 and PKCtheta) have to be considered and that the identification of mutations of KIT et PDGRA may have a diagnostic interest. A new prognostic classification of GIST has been proposed: it acknowledges the existence of truly benign GISTs and is adapted to the primary site of the lesion in order to underline the usually better prognosis of gastric GISTs. The search for mutations of KIT et PDGRA must be done in specialized laboratories. It is important for the evaluation of the sensivity to imatinib, and to the other targeted therapies which may find a role in the treatment of advanced tumors, especially of imatinib-resistent GISTs. Much remains to be done in order to decipher the molecular mechanisms responsible for tumor progression in GISTs: their knowledge will be important to validate new prognostic markers.
 ...
PMID:[Gastrointestinal stroma tumors (GIST): what is new in 2009?]. 1923 89

Primary testicular tumors are the most common causes of cancer in male dogs. Overall, the majority of canine patients should be cured by testicular surgery. However, tumor markers are not well-known in veterinary medicine. We sought to determine using immunohistochemistry whether the combined human testicular tumor markers (placental alkaline phosphatase, OCT3/4, CD30, alpha-fetoprotein, inhibin-alpha, vimentin, c-KIT, and desmin) are expressed in canine seminomas and Sertoli cell tumors (SCTs). We examined 35 canine testicular tumors, 20 seminomas and 15 SCTs. c-KIT was expressed markedly in canine seminomas. Both inhibin-alpha and vimentin were expressed significantly in canine SCTs. The results of this study demonstrate differences and similarities between tumor marker expression of testicular tumors in dogs and humans. All the main markers in current routine use are discussed as well as potential useful markers for benign and malignant tumors, and tumor progression.
 ...
PMID:Comparative immunohistochemical characterization of canine seminomas and Sertoli cell tumors. 1925 17

Gastrointestinal stromal tumors (GISTs) generally harbor activating mutations in KIT or platelet-derived growth facter receptor (PDGFRA). Mutations in these receptor tyrosine kinases lead to dysregulation of downstream signaling pathways that contribute to GIST pathogenesis. GISTs with KIT or PDGFRA mutations also undergo secondary cytogenetic alterations that may indicate the involvement of additional genes important in tumor progression. Approximately 10-15% of adult and 85% of pediatric GISTs do not have mutations in KIT or in PDGFRA. Most mutant adult GISTs display large-scale genomic alterations, but little is known about the mutation-negative tumors. Using genome-wide DNA arrays, we investigated genomic imbalances in a set of 31 GISTs, including 10 KIT/PDGFRA mutation-negative tumors from nine adults and one pediatric case and 21 mutant tumors. Although all 21 mutant GISTs exhibited multiple copy number aberrations, notably losses, eight of the 10 KIT/PDGFRA mutation-negative GISTs exhibited few or no genomic alterations. One KIT/PDGFRA mutation-negative tumor exhibiting numerous genomic changes was found to harbor an alternate activating mutation, in the serine-threonine kinase BRAF. The only other mutation-negative GIST with significant chromosomal imbalances was a recurrent metastatic tumor found to harbor a homozygous deletion in chromosome arm 9p. Similar findings in several KIT-mutant GISTs identified a minimal overlapping region of deletion of approximately 0.28 Mbp in 9p21.3 that includes only the CDKN2A/2B genes, which encode inhibitors of cell-cycle kinases. These results suggest that GISTs without activating kinase mutations, whether pediatric or adult, generally exhibit a much lower level of cytogenetic progression than that observed in mutant GISTs.
 ...
PMID:High density DNA array analysis reveals distinct genomic profiles in a subset of gastrointestinal stromal tumors. 1958 85


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