UMLS:C0376358 - FACTA Search

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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Well-tolerated continuous or metronomic chemotherapy can exert a marked antiangiogenic and thus superior antitumor effect compared with conventional high-dose, temporarily spaced-out chemotherapy, as shown in preclinical studies. There is, however, no means of directly assessing the antiangiogenic effect in a tumor, a serious impediment to assessing the effects of putative antiangiogenic chemotherapeutics or treatments. In an attempt to circumvent or minimize this impediment we studied the antiangiogenic effect of well-tolerated metronomic paclitaxel therapy in a surrogate tumor-free tissue that allows true quantitative analysis as well as in syngeneic At-1 prostate cancer in the same rat. This novel model allows an accurate comparison of the angiogenesis-modulating effect of chemotherapy in the two tissues to be made. The effect of chemotherapy on VEGF-A-mediated angiogenesis, a characteristic of most tumors, was assessed truly quantitatively by microscopic morphometry and image analysis in the tumor-free mesentery. The chemotherapy significantly suppressed VEGF-A-mediated angiogenesis in the mesentery to an extent that closely mirrored the significant increase in tumor necrosis measured morphometrically and the significant decrease in tumor growth rate. This finding opens an avenue to study quantitatively and systematically the antiangiogenic effect of chemotherapeutic modalities and treatments that approximately mirror their antiangiogenic effect in the At-1 tumor.
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PMID:Antiangiogenic effect of metronomic paclitaxel treatment in prostate cancer and non-tumor tissue in the same animals: a quantitative study. 1515 62

Neuropilin-1 (NRP-1), a recently identified co-receptor for vascular endothelial growth factor, is expressed by several nongastrointestinal tumor types and enhances prostate cancer angiogenesis and growth in preclinical models. We investigated the expression and regulation of NRP-1 and the effect of NRP-1 overexpression on angiogenesis and growth of human colon adenocarcinoma by immunohistochemistry and in situ hybridization. NRP-1 was expressed in 20 of 20 human colon adenocarcinoma specimens but not in the adjacent nonmalignant colonic mucosa. By reverse transcriptase-polymerase chain reaction analysis, NRP-1 mRNA was expressed in seven of seven colon adenocarcinoma cell lines. Subcutaneous xenografts of stably transfected KM12SM/LM2 human colon cancer cells overexpressing NRP-1 led to increased tumor growth and angiogenesis in nude mice. In in vitro assays, conditioned medium from NRP-1-transfected cell lines led to an increase in endothelial cell migration, but did not affect endothelial cell growth. Epidermal growth factor (EGF) led to induction of NRP-1 in human colon adenocarcinoma cells and selective blockade of the epidermal growth factor receptor (EGFR) decreased constitutive and EGF-induced NRP-1 expression. Blockade of the Erk 1/2 and P38 mitogen-activated protein kinase signaling pathways also led to a decrease in constitutive and EGF-induced NRP-1 expression. These findings demonstrate the ubiquitous expression of NRP-1 in human colon cancer and suggest that NRP-1 may contribute to colon cancer angiogenesis and growth. This study also suggests that EGF and mitogen-activated protein kinase signaling pathways play an important role in NRP-1 regulation in colon cancer cells.
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PMID:Neuropilin-1 in human colon cancer: expression, regulation, and role in induction of angiogenesis. 1516 48

Glomeruloid microvascular proliferations (GMPs), which are focal proliferative buddings of endothelial cells resembling a renal glomerulus, can be induced experimentally by adenoviral transfer of VEGF-A(165). We recently found that GMPs were present in 13-23% of various human tumours (melanoma, breast-, endometrial- and prostate cancer), and this vascular signature was significantly associated with an impaired prognosis. In the present study, a series of 202 vertical growth phase melanomas were examined for the expression of various angiogenic factors and their receptors. Presence of GMP was associated with increased expression in tumour endothelium of the VEGF-A receptors KDR, FLT-1 and neuropilin-1, as well as VEGF-D protein. Thrombospondin-1 staining in the tumour stroma showed the same relationship. Endothelial cell expression of VEGF-A was increased in GMP endothelium when compared with other intra-tumoural vessels. In contrast, GMP expression of bFGF was decreased. Our findings suggest an important role of VEGF-A and its receptors in GMP formation in human cutaneous melanoma.
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PMID:Increased expression of VEGF-receptors (FLT-1, KDR, NRP-1) and thrombospondin-1 is associated with glomeruloid microvascular proliferation, an aggressive angiogenic phenotype, in malignant melanoma. 1516 98

Lethal phenotypes of human prostate cancer are characterized by progression to androgen-independence and metastasis. For want of a clinically relevant animal model, mechanisms behind this progression remain unclear. Our study used an in vivo model of androgen-sensitive LNCaP human prostate cancer cell xenografts in male SCID mice to study the cellular and molecular biology of tumor progression. Primary tumors were established orthotopically, and the mice were then surgically castrated to withdraw androgens. Five generations of androgen-independent tumors were developed using castrated host mice. Tumor samples were used to determine expressions of cellular and molecular markers. Androgen-independent tumors had increased proliferation and decreased apoptosis compared to androgen-sensitive tumors, outcomes associated with elevated expression of p53, p21/waf1, bcl-2, bax and the bcl-2/bax ratio. Blood vessel growth in androgen-independent tumor was associated with increased expression of vascular endothelial growth factor. Overexpression of androgen receptor mRNA and reduced expression of androgen receptor protein in androgen-independent tumors suggest that the androgen receptor signaling pathway may play an important role in the progression of human prostate cancer to androgen-independence. The in vivo orthotopic LNCaP tumor model described in our study mimics the clinical course of human prostate cancer progression. As such, it can be used as a model for defining the molecular mechanisms of prostate cancer progression to androgen-independence and for evaluating the effect of preventive or therapeutic regimens for androgen-independent human prostate cancer.
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PMID:Progression to androgen-independent LNCaP human prostate tumors: cellular and molecular alterations. 1517 Jun 60

In health, haemostasis and angiogenesis are tightly regulated processes, but may become deregulated in cancer. Recent evidence suggests that platelet activation may link these processes as platelets can release angiogenic factors such as vascular endothelial growth factor (VEGF). Furthermore, inflammation has also been implicated in regulating both coagulation and angiogenesis, possibly by activating platelets directly and increasing, for example, plasma fibrinogen. We hypothesized relationships between plasma markers of the processes in two common forms of cancer. Plasma levels of VEGF (reflecting angiogenesis), soluble P-selectin, (marking platelet activation), tissue factor [TF], fibrinogen and fibrin D-dimer (coagulation markers), and serum levels of IL-6 (inflammation) were measured by ELISA in 30 patients with biopsy-proven breast cancer, 30 patients with biopsy-proven prostate cancer, and 30 age- and sex-matched controls for each group. Prostate specific antigen was also measured in the men. Release of VEGF from IL-6 stimulated platelets was assessed by ELISA. Plasma levels of IL-6 (P <0.02), VEGF, soluble P-selectin, fibrinogen, and fibrin D-dimer (all p <0.01) were significantly raised in breast cancer, whereas VEGF, soluble P-selectin, fibrin D-dimer (all p <0.01) and fibrinogen (p <0.05) were significantly raised in prostate cancer. Significant correlations were found between IL-6 and VEGF (p <0.01), and IL-6 and soluble P-selectin (p = 0.038) in breast cancer. Further experiments demonstrated an in vitro IL-6 induced dose-dependent release of VEGF from platelets. In conclusion, strong relationships between IL6 and VEGF, but not with coagulation or platelet markers, and release of VEGF from IL-6 stimulated platelets, suggest a role for inflammation and platelets in angiogenesis.
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PMID:Platelet activation, coagulation and angiogenesis in breast and prostate carcinoma. 1521 60

The aim of the study was to quantify the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) in prostate cancer and adjacent non-tumorous tissue in a standardized experimental set-up and to evaluate the paracrine effects of three endothelial stimuli on neovascularisation. Immunohistochemical staining of prostate cancer (PCa) specimens for VEGF, bFGF, EGF and the endothelial marker CD31 was performed (n=56). Sections were analyzed for growth factor-positive cancer/epithelial cells as well as staining intensity in (I) malignant and (II) non-tumorous tissue. Within PCa the topographic relationship (TR) of maximum microvessel density (MWD) and maximum expression of each growth factor was assessed. The number of VEGF- and EGF-positive cells in PCa was significantly enhanced compared with non-tumorous tissue (p<0.0001), whereas there was no difference in staining intensity. In contrast, the staining intensity of bFGF sections revealed a stronger expression in non-tumorous tissue compared with PCa (p<0.0001). In benign glands, VEGF, EGF and bFGF expression is chiefly restricted to basal cells. VEGF and EGF displayed a close TR in 65 and 57% of cases, respectively, whereas bFGF revealed a close TR in only 43% of PCa specimens. The results outline the relationship of the investigated growth factors and angiogenesis in PCa, which is strongest for VEGF and EGF. The relevance of VEGF and EGF is underlined by the increased number of positive cancer cells. Although previously reported to be a pro-angiogenic growth hormone, bFGF appears to play an assimilably minor role in the angiogenesis of PCa.
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PMID:Expression of pro-angiogenic growth factors VEGF, EGF and bFGF and their topographical relation to neovascularisation in prostate cancer. 1525 Jan 2

We hypothesize that expression of proangiogenic genes correlates with the metastatic potential of prostate cancer cells. LNCaP, DU-145, and PC-3 are prostate cancer cell lines with low, moderate, and high metastatic potential, respectively, as we demonstrated by their capacity to invade an extracellular matrix, an established tumor invasion assay. The constitutive gene expression of the proangiogenic factors, vascular endothelial growth factor, intercellular adhesion molecule-1, interleukin-8, and transforming growth factor-beta2, was significantly greater in the more metastatic DU-145 and PC-3 cells as compared with LNCaP cells. Matrix metalloproteinase (MMP)-9 is thought to contribute to the invasive phenotype of tumor cells. PC-3 cells showed increased expression of MMP-9 and membrane type 4-MMP as compared with LNCaP and DU-145. Tissue inhibitors of metalloproteinase 1 and 4 gene expression were elevated in DU-145 and PC-3 cells, but paradoxically, LNCaP cells had undetectable levels of these genes. We transfected and overexpressed MMP-9 in poorly metastatic LNCaP cells and measured their invasive activity. Transient expression of human MMP-9 in LNCaP cells produced a 3-5-fold increase in MMP-9 activity with a comparable increase in invasiveness. Antisense ablation of the expression of MMP-9 in DU-145 and PC-3 cells produced concomitant inhibition of the gene expression of the proangiogenic factors, vascular endothelial growth factor, and intercellular adhesion molecule-1 (ICAM-1). Treatment of DU-145 and PC-3 cells with a selective chemical inhibitor of MMP-9 proteinase activity also inhibited their invasive activity. These results support our hypothesis that metastatic potential of prostate cancer cells correlates with expression of proangiogenic factors.
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PMID:Gene expression of angiogenic factors correlates with metastatic potential of prostate cancer cells. 1528 37

Recent evidence suggests that androgens stimulate growth of human prostate cancer partly by regulating expression of growth factors such as vascular endothelial growth factor (VEGF) in vitro and in vivo. In this study, we used CWR22Rv1, a novel androgen-responsive but androgen-independent human prostate cancer model, to evaluate the effect of androgen withdrawal on tumor growth, expression of VEGF and the cell proliferation marker Ki-67, and angiogenesis. A time-release testosterone pellet was implanted three days before inoculation of CWR22Rv1 cells in the mice. The tumor volumes were measured every three days. Serum PSA was measured on days 1, 12, 20, 27 and 34 post inoculation. Castration was performed on the 20th day post inoculation. Immunohistochemical assays were used to evaluate cell proliferation and microvessel density. Enzyme-linked immunosorbent assay (ELISA) was used to quantify VEGF expression. The average tumor volumes in the castration group on the 27th and 34th days were 122 and 168 mm3, respectively, compared to 156 and 210 mm3 in the non-castration group (p<0.01). Serum PSA level in the castration group decreased to about 41% of the level of the non-castration group (p<0.01). The VEGF protein levels in the tumors of castrated and non-castrated mice on day 34 were 0.62 pg and 1.36 pg/100 microg total protein, respectively (p<0.001). The mean percentage of Ki-67-positive tumor cells in the castrated and non-castrated groups were 1.8% and 2.8%, respectively (p=0.015). The mean microvessel densities in the castrated and non-castrated groups were 15 and 22 vessels/field, respectively (p<0.01) We conclude androgen withdrawal reduced both VEGF and microvessel density, and this was associated with decreased cellular proliferation in androgen-independent CWR22Rv1 human prostate cancer tumor in vivo.
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PMID:Androgen withdrawal inhibits tumor growth and is associated with decrease in angiogenesis and VEGF expression in androgen-independent CWR22Rv1 human prostate cancer model. 1533 Jan 53

Growth of new blood vessels (angiogenesis), required for all tumor growth, is stimulated by the expression of vascular endothelial growth factor (VEGF). VEGF is up-regulated in all known solid tumors but also in atherosclerosis, diabetic retinopathy, arthritis, and many other conditions. Conventional VEGF isoforms have been universally described as proangiogenic cytokines. Here, we show that an endogenous splice variant, VEGF(165)b, is expressed as protein in normal cells and tissues and is circulating in human plasma. We also present evidence for a sister family of presumably inhibitory splice variants. Moreover, these isoforms are down-regulated in prostate cancer. We also show that VEGF(165)b binds VEGF receptor 2 with the same affinity as VEGF(165) but does not activate it or stimulate downstream signaling pathways. Moreover, it prevents VEGF(165)-mediated VEGF receptor 2 phosphorylation and signaling in cultured cells. Furthermore, we show, with two different in vivo angiogenesis models, that VEGF(165)b is not angiogenic and that it inhibits VEGF(165)-mediated angiogenesis in rabbit cornea and rat mesentery. Finally, we show that VEGF(165)b expressing tumors grow significantly more slowly than VEGF(165)-expressing tumors, indicating that a switch in splicing from VEGF(165) to VEGF(165)b can inhibit tumor growth. These results suggest that regulation of VEGF splicing may be a critical switch from an antiangiogenic to a proangiogenic phenotype.
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PMID:VEGF165b, an inhibitory vascular endothelial growth factor splice variant: mechanism of action, in vivo effect on angiogenesis and endogenous protein expression. 1552 Jan 88

The aberrant behavior of cancer reflects upregulation of certain oncogenic signaling pathways that promote proliferation, inhibit apoptosis, and enable the cancer to spread and evoke angiogenesis. Theoretically, it should be feasible to decrease the activity of these pathways-or increase the activity of pathways that oppose them-with noncytotoxic agents. Since multiple pathways are dysfunctional in most cancers, and cancers accumulate new oncogenic mutations as they progress, the greatest and most durable therapeutic benefit will likely be achieved with combination regimens that address several targets. Thus, a multifocal signal modulation therapy (MSMT) of cancer is proposed. This concept has already been documented by researchers who have shown that certain combinations of signal modulators-of limited utility when administered individually-can achieve dramatic suppression of tumor growth in rodent xenograft models. The present essay attempts to guide development of MSMTs for prostate cancer. Androgen ablation is a signal-modulating measure already in standard use in the management of delocalized prostate cancer. The additional molecular targets considered here include the type 1 insulin-like growth factor receptor, the epidermal growth factor receptor, mammalian target of rapamycin, NF-kappaB, hypoxia-inducible factor-1alpha, hsp90, cyclooxygenase-2, protein kinase A type I, vascular endothelial growth factor, 5-lipoxygenase, 12-lipoxygenase, angiotensin II receptor type 1, bradykinin receptor type 1, c-Src, interleukin-6, ras, MDM2, bcl-2/bclxL, vitamin D receptor, estrogen receptor-beta, and PPAR-. Various nutrients and phytochemicals suspected to have potential utility in prostate cancer prevention and therapy, but whose key molecular targets are still unknown, might reasonably be incorporated into MSMTs for prostate cancer; these include lycopene, selenium, green tea polyphenols, genistein, and silibinin. MSMTs can be developed systematically by testing various combinations of signal-modulating agents, in concentrations that can feasibly be achieved and maintained clinically, on human prostate cancer cell lines; combinations that appear promising can then be tested in xenograft models and, ultimately, in the clinic. Some signal modulators can increase response to cytotoxic drugs by upregulating effectors of apoptosis. When MSMTs fail to raise the spontaneous apoptosis rate sufficiently to achieve tumor stasis or regression, incorporation of appropriate cytotoxic agents into the regimen may improve the clinical outcome.
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PMID:Targeting multiple signaling pathways as a strategy for managing prostate cancer: multifocal signal modulation therapy. 1552 6

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