Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inflammation-induced localized bone resorption in diseases such as marginal and apical periodontitis, rheumatoid arthritis, and osteomyelitis is due to activation and recruitment of osteoclasts by locally produced cytokines and inflammatory mediators. Thus several interleukins (1, 3, 4, 6, and 11), tumor necrosis factors (alpha, beta), colony-stimulating factors (M and GM), leukemia inhibitory factor, gamma-interferon, and transforming growth factor-beta have effects on bone resorption and bone formation in vivo and in vitro. The kallikrein-kinin system and the coagulation cascade are also activated in inflammation. We have found that peptides produced in the kallikrein-kinin system (bradykinin, kallidin) and thrombin, the end product in the coagulation cascade, can stimulate bone resorption in vitro. The stimulatory effect of bradykinin is linked both to B1 and B2 bradykinin receptors. Both kinins and thrombin stimulate prostaglandin biosynthesis in bone parallel with the bone resorptive effect. The stimulatory effect of bradykinin on bone resorption is completely lost when the prostaglandin response is abolished, whereas thrombin can stimulate bone resorption both via prostaglandin-dependent and independent mechanisms. In addition, bradykinin and thrombin act in concert with interleukin-1 to synergistically stimulate bone resorption and prostaglandin biosynthesis. We also have found that one of the acute-phase reactants, haptoglobin, can stimulate bone resorption in vitro, indicating the possibility of generalized bone loss in chronic inflammatory diseases. Moreover, haptoglobin synergistically potentiates bradykinin-induced and thrombin-induced prostanoid biosynthesis in osteoblasts. These observations indicate that the rate of bone resorption in inflammation-induced bone loss may not be due to a single factor but to the concerted action of several local or systemic factors.
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PMID:Regulation of bone metabolism by the kallikrein-kinin system, the coagulation cascade, and the acute-phase reactants. 752 72

PSA is a 34-kDa 240-amino-acid glycoprotein produced exclusively by prostatic epithelial cells. PSA is a serine protease, is a member of the kallikrein gene family, and has a high sequence homology with human glandular kallikrein. It has chymotrypsin-, trypsin-, and esterase-like activities. In the serum it is present mainly in a complex form with alpha 1-antichymotrypsin. It is secreted in the seminal plasma and is responsible for liquefaction of the seminal coagulum. The production of PSA proteins appears to be under the control of circulating androgens acting through the androgen receptors. The PSA gene is up-regulated predominantly by androgens at both the protein and mRNA levels. DRE causes minimal changes in the PSA level, while prostate massage, ultrasonography, systoscopic examination, and prostate biopsy can all cause clinically significant elevations. Other conditions, such as prostatitis, prostate intraepithelial neoplasia, acute urinary retention, and renal failure can also elevate the PSA level. The value of PSA as a screening tool is questionable because of the great deal of overlap in PSA levels between BPH and prostate cancer. However, if used in men over 50, in conjunction with DRE and/or ultrasonography, it may become a vital part of the early detection program. PSA's role in determining the clinical and pathological stage is also limited, in spite of the direct correlation between the pathological stage and the PSA level, because of great overlap in the PSA levels in various stages. The most important clinical utility of PSA is in monitoring patients after definitive therapy. PSA is most sensitive and reliable in the detection of a residual tumor, possibly recurrence, or disease progression following treatment, irrespective of the treatment modality. PSA can accurately predict the tumor status and can detect recurrence several months before its detection by any other method. PSA is also a very sensitive and specific immunohistochemical marker for tumors of prostatic origin. Compared to PAP, PSA is a more precise and meaningful marker in all clinical situations. With the development of ultrasensitive assays and the adoption of an international standard PSA calibrator, so that results from multicenter studies can be compared, PSA could become one of the most useful tumor marker in cancer biology.
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PMID:Prostatic specific antigen. 753 74

Our followup study of 48 patients with primary aldosteronism concerns the results of 2 different operative methods. After preoperative localization of the unilateral solitary tumor 22 patients underwent unilateral adrenalectomy and 26 underwent enucleation of aldosterone-producing adenoma. Both operative methods improved hypertension, hypokalemia, the low urinary sodium-to-potassium ratio, suppressed plasma renin activity, high plasma aldosterone concentration, high urinary aldosterone excretion and high urinary kallikrein excretion in similar orders of magnitude for 5 years. Levels of plasma cortisol and plasma adrenocorticotropic hormone following respective operations were also identical. Five years postoperatively, ambulation and furosemide administration under low sodium diet stimuli remarkably enhanced plasma renin activity and plasma aldosterone concentration in the aldosterone-producing adenoma enucleation group (p < 0.001), almost similar to that of normal subjects but increment magnitudes were slight (p < 0.05 to < 0.01) in the adrenalectomy group. Preoperatively, angiotensin II infusion failed to increase plasma aldosterone concentration in patients with primary aldosteronism. After respective operations, responses of plasma aldosterone concentration to angiotensin II infusion and of plasma cortisol to adrenocorticotropic hormone administration in the aldosterone-producing adenoma enucleation group were more sensitive than those in the adrenalectomy group. There was no remission of recurrent hyperaldosteronism in either group throughout the study. These results suggest that angiotensin II induces aldosterone release by an activation of tumor uninvolved cortical cells and that the enucleation of aldosterone-producing adenoma is more preferable than unilateral adrenalectomy.
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PMID:Therapeutic outcome of primary aldosteronism: adrenalectomy versus enucleation of aldosterone-producing adenoma. 775 16

Vascular pathophysiology at the sites of bacterial infection and cancerous tissues share numerous common events similar to inflammatory tissue. Among them enhanced vascular permeability is the universal and hallmark event mediated by bradykinin. All 16 or more bacterial or fungal proteases we have examined activated one or more steps of the kinin generating Hageman-factor-kallikrein cascade. In the meantime, most of the microbial proteases rapidly inactivated various plasma inhibitors such as alpha 1-protease inhibitor and alpha 2-macroglobulin. In addition to the extracellular proteases, bacterial cell wall components (negatively charged LPS) of gram-negative bacteria and teichoic acid moieties of gram-positive bacteria activate the Hageman-factor-kallikrein system and exert hypotensive effects via kinin generation. Endotoxin (LPS) also induces nitric oxide synthase (NOS) which appears to exhibit a rather slow, but significant, effect in relaxing the vascular tone of the infected animal (thus hypotension). Furthermore, bacterial proteases can activate the matrix metalloproteinase (collagenase) resulting in exacerbation of tissue injury in the diseased animal. Many tumor cells or tissues excrete plasminogen activator, and hence activate plasminogen. The plasmin thus generated activates procollagenases, as well as the Hageman-factor-kallikrein system, resulting in pronounced extravasation. Fluid accumulation in pleural and ascitic carcinomatoses is largely due to the activated bradykinin-generating system. We can also demonstrate and control enhanced vascular permeability using kallikrein inhibitors, especially the polymer-conjugated soybean trypsin inhibitor which exhibits a prolonged plasma t1/2, kinin antagonists, NOS inhibitors, NO scavengers, inhibitors of prostaglandins and others. Bacterial proteases induce shock in mice which can be prevented by the soybean trypsin inhibitor by blocking the kallikrein-kinin cascade. Therapeutic use of kinin antagonists and a kallikrein inhibitor has been made for infectious diseases such as septicemia and in tumor pathology.
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PMID:Bradykinin and nitric oxide in infectious disease and cancer. 885 54

The human kallikrein family consists of three members, hK1, hK2, and hK3 [prostate-specific antigen (PSA)]. PSA is a widely accepted marker for prostate cancer. The mRNAs for both hK2 and PSA are localized predominantly to prostate epithelium and are regulated by androgens. In addition, hK2 has 78% amino acid homology to PSA. Although similarities to PSA make hK2 a potential prostate cancer marker, they also impede biochemical characterization of hK2 in those human tissues and body fluids where PSA is abundant. To study the expression, biosynthesis, and processing of hK2, recombinant hK2 was expressed in the adenovirus-induced Syrian hamster tumor cell line AV12-664 (AV12-hK2). Expression of hK2 was analyzed by Western blots and ELISA using monoclonal antibodies HK1G 464.3 [specific for prohK2 (phK2)] and HK1D 106.4 [specific for phK2 and mature hK2 (hK2)1. Western blot and ELISA analyses showed that phK2 was secreted into the media by AV12-hK2 cells on day 1 and was gradually converted to the mature form of hK2 by day 7. N-terminal amino acid sequencing verified the Western blot and ELISA data. This demonstrates for the first time that hK2 is secreted as phK2 and converted to hK2 extracellularly. In addition, hK2 detected in day 4-7 AV12-hK2-spent media was enzymatically active. Recombinant hK2 was also expressed in human prostate carcinoma cell lines, PC3 (PC3-hK2) and DU145 (DU145-hK2), that do not express endogenous hK2 or PSA. Similar to AV12-hK2 cells, both cell lines secreted phK2 that was converted to hK2 extracellularly. phK2 was the major form detected in the spent media of PC3-hK2 cells, even after 7 days, indicating a slow conversion of phK2 to hK2. hK2 was the predominant form detected in the spent media of DU145-hK2 starting on day 1, indicating the rapid conversion of phK2 to hK2. In this study, we demonstrate that hK2 exists in different forms and is secreted as phK2. phK2 is then converted to enzymatically active hK2 extracellularly.
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PMID:Expression of human glandular kallikrein, hK2, in mammalian cells. 896 92

The development of monoclonal antibodies directed against prostatic kallikrein hK2 prompted us to evaluate its content, along with that of hK3 (prostate-specific antigen), in human prostate carcinoma. Seventy tumors categorized according to the M.D. Anderson Hospital classification (grade I to IV) were analyzed by immunohistochemistry. The staining intensity or the kallikrein content of benign prostatic hyperplasia glandular tissue (used as control) and of grade I tumors appeared similar. In grade II to IV tumors, histochemical data revealed highly variable hK2 or hK3 content in approximately 25% of tumors. Such patterns are consistent with a current observation related to heterogeneity of prostate tumors. In addition, a few tumors did not express hK3 (n = 3), hK2 (n = 3), or both (n = 3), indicating that some growth patterns of prostatic neoplasia are associated with a lack of secretion or storage of hK3 or hK2 for immunodetection. This statement also appears relevant to metastases. It was interesting to note that 4% of hK3-negative tumors had detectable hK2. Because of the importance of hK3 as a serum marker of prostate disorder, this study addresses for the first time the question of the relative importance of both hK3 and hK2 in the immunohistochemical diagnosis of prostatic tumors. We conclude that hK2 may add new information to prostate cancer diagnosis and characterization.
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PMID:Immunohistochemical study suggesting a complementary role of kallikreins hK2 and hK3 (prostate-specific antigen) in the functional analysis of human prostate tumors. 903 61

To study the expression, biosynthesis, and processing of prostate-specific antigen (PSA) in mammalian cells, recombinant PSA was expressed in Syrian hamster tumor cell line AV12-664 (AV12-PSA). Expression of PSA was monitored by the Tandem-MP PSA assay. PSA was secreted into the medium during the logarithmic phase of cell growth at >9 microg/ml and was stable. The PSA purified from spent medium of AV12-PSA cells did not exhibit any enzymatic activity and did not complex with the protease inhibitor, alpha-1-antichymotrypsin. These findings indicated that an inactive form of PSA was expressed by AV12-PSA cells. NH2-terminal sequencing confirmed the identity of the PSA purified from the spent medium of AV12-PSA cells to be pro-PSA. This demonstrates that PSA is expressed as pro-PSA by mammalian cells and suggests that pro-PSA may be present in biological fluids. Human kallikrein 2 (hK2), another member of the hK family, is also expressed predominantly in prostate epithelium. Although hK2 has been shown to exhibit trypsin-like activity, little is known about its natural substrates. Using purified proteins, we show that hK2 can convert pro-PSA to mature, enzymatically active PSA, thus establishing a physiological connection between hK2 and PSA. These findings imply that hK2 may be regulating PSA activity in vivo.
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PMID:Expression of pro form of prostate-specific antigen by mammalian cells and its conversion to mature, active form by human kallikrein 2. 924 34

Prostate-specific antigen (PSA) is the most important tumor marker for prostate cancer, although it is not a perfect marker as it is not cancer-specific. PSA, a member of the human kallikrein family, is present in two molecular forms in serum: free and complexed to protease inhibitors. PSA is now commonly measured on automated immunoassay systems employing monoclonal or polyclonal antibodies. Results from different assays can vary since some assays are not equimolar and react to the free and complexed forms differently. Utilization of the molecular forms of PSA is one approach to improve the sensitivity and specificity of the PSA assay. Patients with prostate cancer have a greater percentage of PSA bound to alpha1-antichymotripsin (ACT) than those without cancer. Measurement of the free to total PSA ratio in the diagnostic gray zone (usually 4-10 micrograms/liter of total PSA), where prostate cancer and benign prostatic hyperplasia (BPH) overlap, has been shown to eliminate between 16 and 79% of unnecessary biopsies. Free to total PSA cutoffs are influenced by the sensitivity and specificity values chosen, the reflex range for total PSA used, differences in free PSA assays, differences in populations studied, and factors such as total PSA concentrations, age, and prostate gland size. In addition to the molecular forms of PSA, age-specific reference ranges, rate of change of PSA concentrations (PSA velocity), ratio of serum PSA to prostate volume (PSA density), and neural network derived indices have been employed to improve the clinical utility of PSA measurements.
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PMID:Prostate-specific antigen: update 1997. 1017 23

Human glandular kallikrein (hK2) and prostate-specific antigen (PSA) are related members of the human kallikrein gene family. The genes for hK2 and PSA are expressed predominately in the prostate, are transcriptionally up-regulated by androgens, and share 78% homology. Previously, one functional androgen response element was identified within the proximal promoter (-324 to +33 relative to the cap site) of the hK2 gene. To detect additional upstream regulatory elements, the 12.3 kbp between the PSA gene and 5' to the hK2 gene were amplified by PCR and linked to a promoterless firefly luciferase reporter gene. Transient transfection experiments showed an androgen-dependent enhancer, located between -3.4 and -5.2 kb upstream of the transcription start site of the hK2 gene. This hK2 enhancer increased luciferase expression 100-fold in the presence of the testosterone analogue R1881. The hK2 enhancer contains an androgen response element that lost activity when mutated. The hK2 enhancer/promoter demonstrated activity in PSA(+) LNCaP cells whereas the enhancer/promoter was inactive in PSA(-) 293, A549, HBL100, HUH-7, LoVo, MCF-7, OVCAR-3, and PC-3 cells. Insertion of the hK2 enhancer/promoter into adenovirus to drive the E1A genes of adenovirus type 5 (Ad5) created an attenuated replication competent adenovirus variant Calydon virus (CV) 763, which replicates similarly to wild-type adenovirus in prostate tumor cells but is attenuated in nonprostate tumor cells. In addition, CV764, an adenovirus variant containing the previously cloned prostate-specific enhancer (to drive the Ad5 E1A genes) and the hK2 enhancer/promoter (to drive the Ad5 E1B genes) was constructed. CV764 is significantly attenuated and has a high therapeutic index with a cell specificity of 10,000:1 for PSA(+) LNCaP cells, compared to ovarian cancer OVCAR-3 cells and SK-OV-3 cells and PA-1 cells. CV764 is also highly attenuated in primary human microvascular endothelial cells.
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PMID:Identification of the transcriptional regulatory sequences of human kallikrein 2 and their use in the construction of calydon virus 764, an attenuated replication competent adenovirus for prostate cancer therapy. 1019 20

A better understanding of the molecular changes associated with the onset and progression of prostate cancer may provide us with a rational basis for the development of new diagnostic and therapeutic tools. Likewise, the recent identification of critical biochemical pathways, including angiogenesis, programmed cell death, cell adhesion and signal transduction, provide us with promising targets for therapeutic approaches. Furthermore, the identification and characterization of new tumor-specific antigens or prostate-cancer-specific gene promoters could be instrumental for the development of new treatment modalities. Many research groups are trying to identify genes that are involved in prostate cancer development and which may serve as new tumor markers and potential targets for therapy. In addition to prostate-specific antigen, prostate-specific membrane antigen and human kallikrein-2, the recently identified prostate stem cell antigen may also provide us with a new tool for the diagnosis and treatment of prostate cancer. Our own studies led to the identification of DD3, a gene that is strongly overexpressed in human prostatic cancers and the expression of which appears to be restricted to the prostate. Further studies are necessary to establish the clinical usefulness of these new prostate-cancer-specific genes for the management of prostate cancer patients.
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PMID:Changes in gene expression and targets for therapy. 1032 97


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