Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Preneoplastic and neoplastic hepatocytes undergo c-Myc up-regulation and overgrowth in rats genetically susceptible to hepatocarcinogenesis, but not in resistant rats. Because c-Myc regulates the pRb-E2F pathway, we evaluated cell cycle gene expression in neoplastic nodules and hepatocellular carcinomas (HCCs), induced by initiation/selection (IS) protocols 40 and 70 weeks after diethylnitrosamine treatment, in susceptible Fisher 344 (F344) rats, and resistant Wistar and Brown Norway (BN) rats. No interstrain differences in gene expression occurred in normal liver. Overexpression of c-myc, Cyclins D1, E, and A, and E2F1 genes, at messenger RNA (mRNA) and protein levels, rise in Cyclin D1-CDK4, Cyclin E-CDK2, and E2F1-DP1 complexes, and pRb hyperphosphorylation occurred in nodules and HCCs of F344 rats. Expression of Cdk4, Cdk2, p16(INK4A), and p27(KIP1) did not change. In nodules and/or HCCs of Wistar and BN rats, low or no increases in c-myc, Cyclins D1, E, and A, and E2F1 expression, and Cyclin-CDKs complex formation were associated with p16(INK4A) overexpression and pRb hypophosphorylation. In conclusion, these results suggest deregulation of G1 and S phases in liver lesions of susceptible rats and block of G1-S transition in lesions of resistant strains, which explains their low progression capacity.
 ...
PMID:Cell cycle deregulation in liver lesions of rats with and without genetic predisposition to hepatocarcinogenesis. 1202 19

Current evidence indicates that neoplastic nodules induced in liver of Brown Norway (BN) rats genetically resistant to hepatocarcinogenesis are not prone to evolve into hepatocellular carcinoma. We show that BN rats subjected to diethylnitrosamine/2-acetylaminofluorene/partial hepatectomy treatment with a "resistant hepatocyte" protocol displayed higher number of glutathione-S-transferase 7-7(+) hepatocytes when compared with susceptible Fisher 344 (F344) rats, both during and at the end of 2-acetylaminofluorene treatment. However, DNA synthesis declined in BN but not F344 rats after completion of reparative growth. Upregulation of p16(INK4A), Hsp90, and Cdc37 genes; an increase in Cdc37-Cdk4 complexes; and a decrease in p16(INK4A)-Cdk4 complexes occurred in preneoplastic liver, nodules, and hepatocellular carcinoma of F344 rats. These parameters did not change significantly in BN rats. E2f4 was equally expressed in the lesions of both strains, but Crm1 expression and levels of E2f4-Crm1 complex were higher in F344 rats. Marked upregulation of P16(INK4A) was associated with moderate overexpression of HSP90, CDC37, E2F4, and CRM1 in human hepatocellular carcinomas with a better prognosis. In contrast, strong induction of HSP90, CDC37, and E2F4 was paralleled by P16(INK4A) downregulation and high levels of HSP90-CDK4 and CDC37-CDK4 complexes in hepatocellular carcinomas with poorer prognosis. CDC37 downregulation by small interfering RNA inhibited in vitro growth of HepG2 cells. In conclusion, our findings underline the role of Hsp90/Cdc37 and E2f4/Crm1 systems in the acquisition of a susceptible or resistant carcinogenic phenotype. The results also suggest that protection by CDC37 and CRM1 against growth restraint by P16(INK4A) influences the prognosis of human hepatocellular carcinoma.
 ...
PMID:Role of HSP90, CDC37, and CRM1 as modulators of P16(INK4A) activity in rat liver carcinogenesis and human liver cancer. 1631 7

We previously reported that the frequency of polyploid aortic vascular smooth muscle cells (VSMC) serves as a biomarker of aging. Cellular senescence of somatic cells is another marker of aging that is characterized by the inability to undergo cell division. Here, we examined whether polyploidy is associated with the development of cellular senescence in vivo. Analysis of aortic tissue preparations from young and old Brown Norway rats showed that expression of senescence markers such as p16(INK4a) and senescence-associated beta-galactosidase activity are detected primarily in the old tissues. VSMC from p16(INK4a) knockout and control mice display similar levels of polyploid cells. Intriguingly, senescence markers are expressed in most, but not all, polyploid VSMC. Moreover, the polyploid cells exhibit limited proliferative capacity in comparison to their diploid counterparts. This study is the first to demonstrate in vivo that polyploid VSMC adopt a senescent phenotype.
 ...
PMID:Increased polyploidy in aortic vascular smooth muscle cells during aging is marked by cellular senescence. 1729 Dec 94

Low-grade serous carcinoma (LGSC) of the ovary has only recently been recognized as a disease entity distinct from the more common high-grade serous carcinoma (HGSC). When confined to the ovary, LGSC is associated with a very favorable prognosis, and chemotherapy is typically not recommended. There is little available information on the prognosis of patients with LGSC with extraovarian spread, from population-based tumor registries where there has been full pathology review. Thirty-two cases of Stage II to IV ovarian LGSC were identified in the Cheryl Brown Ovarian Cancer Outcomes Unit (1984-2000). In 19 cases, blocks were available and immunostaining for p53, p16, Ki-67, WT1, and E-cadherin was performed. Expression of these markers was then compared with a series of >400 cases of HGSC from the outcomes unit. LGSCs presented at Stage II in 10/32 cases, Stage III in 21/32 cases, and Stage IV in 1/32 cases. On follow-up, most patients died of disease, with <30% survival at 10 years. Compared with HGSCs, the LGSCs were significantly less likely to express p16 at high levels, or to show abnormal p53 expression (P=0.049 and <0.0001, respectively). Ki-67 staining indices were lower in the LGSCs (P<0.0001). There were no significant differences between LGSCs and HGSCs with respect to expression of WT1 and E-cadherin (P=0.27 and 0.62, respectively). This population-based series of LGSC with extraovarian spread at presentation had an unfavorable prognosis, similar to that of HGSC. As previously reported, LGSC shows lower tumor proliferation and fewer p53 abnormalities than in HGSC.
...
PMID:Stage II to IV low-grade serous carcinoma of the ovary is associated with a poor prognosis: a clinicopathologic study of 32 patients from a population-based tumor registry. 2407 67