Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0598934 (tumor growth)
 58,965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We had previously reported that 6-methylene progesterone, an inhibitor of 5 alpha-reductase, the enzyme which converts testosterone to dihydrotestosterone, markedly inhibited growth of the androgen-dependent Dunning R3327-H rat prostatic tumors. We now find that the progesterone derivatives melengestrol acetate (MGA) and megestrol acetate (MA) inhibit both the androgen-dependent (Dunning R3327-H) and the androgen-independent (Dunning R3327-AT3) prostatic tumors. Growth of the AT3 tumors was suppressed by approximately 53% after 9 days of daily s.c. injections with MGA at 10 mg/kg body weight. MGA also caused a 54% weight reduction of the ventral prostate and a 53% reduction of the seminal vesicles. Adrenal weights were reduced by 42%. A 24-day oral treatment with MGA (at approximately 15-17 mg/(kg.day)) inhibited AT3 tumor growth by 59% and caused a weight reduction in the following tissues: prostate (46%), seminal vesicles (19%), testes (12%), and adrenals (52%). Under the same protocol, MA inhibited AT3 tumor growth by 32% and reduced the weight of the ventral prostate by 49% and the weight of the adrenals by 18%, but had no effect on the seminal vesicles and testes. The extent of the MGA-induced prostatic regression was accompanied by cytological changes similar to those effected by 6-methylene progesterone, i.e., shrinking of the acinar epithelium. The AT3 tumors in MGA-treated rats displayed a limited degree of apoptosis. Atrophy of the adrenal cortex and lowered plasma levels of corticosterone and dihydroepiandrosterone were also observed. A therapeutic role for MGA and MA against androgen-independent prostatic neoplasms in man is forecast by these observations.
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PMID:Melengestrol acetate and megestrol acetate are prostatic tumor inhibiting agents. 226 13

Metastasis represents a hallmark of the tumor cell's escape from normal cellular behavior to acquired invasive and migratory style. Metastasis of prostate cancer (Pca) depends upon the interplay of a series of hematogenous and hematopoietic factors. We investigated the role of some of those factors implicated in the dissemination process in two separate sublines of adenocarcinoma of the prostate. Our data revealed that (1) the urokinase plasminogen activator activity was significantly higher in R3327-AT3, an aggressive metastatic tumor, as compared to R3327-G, a nonmetastatic tumor of the prostate, (2) the concentration of platelets decreased, and the platelet-aggregating activity increased significantly when the platelets were reacted with exogenous aggregating agents and tumor effusions to suggest that activation of the hemostatic system could protect tumor cells from immunosurveillance and facilitate the process of hematogenous dissemination, and (3) transferrin, which has been reported to have a growth-promoting effect on Pca, did not show any appreciable effect on tumor growth but did alter the level of in vitro adherence which possibly could lead to better attachment and increased invasive behavior of tumor cells.
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PMID:Metastatic behavior of prostatic tumor as influenced by the hematopoietic and hematogenous factors. 898 19

The molecular mechanisms leading to prostate cancer remain poorly understood, especially concerning the progression to the metastatic form. SSeCKS, a major protein kinase C substrate with tumor suppressor activity, is likely the rodent orthologue of human Gravin/AKAP12, a scaffolding protein for protein kinases A and C. Gravin was mapped as a single-copy gene to 6q24-25.2, a hotspot for deletion in advanced prostate cancer, and therefore, we investigated the role of SSeCKS/Gravin in prostate oncogenesis. SSeCKS/Gravin protein was detected in untransformed rat and human prostate epithelial cell lines EP12 and PZ-HPV-7, respectively, and in human prostatic epithelium, especially basal epithelial cells. In contrast, SSeCKS/Gravin protein and RNA levels were severely reduced in human (PC-3, PPC-1, LNCaP, DU145, and TSU) and rat Dunning (AT3.1 and MatLyLu) prostate cancer cell lines. The regulated reexpression of SSeCKS in MatLyLu cells induced filopodia-like projections and a decrease in anchorage-independent growth. In nude mice, SSeCKS reexpression slightly decreased primary-site tumor growth but severely decreased the formation of lung metastases. Primary-site tumors that progressed lost regulated SSeCKS reexpression. SSeCKS/Gravin expression was detected in benign human prostatic lesions and well-differentiated carcinomas but not in undifferentiated lesions with Gleason sums > or =6. Our data suggest a role for the loss of SSeCKS/Gravin in the metastatic progression of human prostate cancer.
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PMID:The Src-suppressed C kinase substrate, SSeCKS, is a potential metastasis inhibitor in prostate cancer. 1145 19

Calreticulin is an essential, multifunctional Ca(2+)-binding protein that participates in the regulation of intracellular Ca(2+) homeostasis, cell adhesion, and chaperoning. Calreticulin is abundantly expressed and regulated by androgens in prostate epithelial cells. Given the importance of both calreticulin in multiple essential cellular activities and androgens in prostate cancer, we investigated the possibility of a role for calreticulin in prostate cancer progression. Immunohistochemistry revealed the down-regulation of calreticulin in a subset of human prostate cancer specimens. Prostate cancer cells overexpressing exogenous calreticulin produced fewer colonies in both monolayer culture and soft agar. Furthermore, calreticulin overexpression also inhibited tumor growth in the orthotopic PC3 xenograft tumor model and macroscopic lung metastasis in the rat Dunning AT3.1 prostate tumor model. To address the potential mechanism of calreticulin suppression of prostate cancer, we generated calreticulin mutants with different functional domains deleted. The calreticulin mutants containing the P-domain, which binds to other endoplasmic reticulum chaperone proteins, were sufficient for the suppression of PC3 growth in colony formation assays. Overall, our data support the hypothesis that calreticulin inhibits growth and/or metastasis of prostate cancer cells and that this suppression requires the P-domain.
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PMID:Suppressive roles of calreticulin in prostate cancer growth and metastasis. 1960 64