Previously it has been reported that caveolin-1 (cav-1) has antiapoptotic activities in prostate cancer cells and functions downstream of androgenic stimulation. In this study, we demonstrate that cav-1 overexpression significantly reduced thapsigargin (Tg)-stimulated apoptosis. Examination of the phosphatidylinositol 3-kinase (PI3-K)/Akt signaling cascade revealed higher activities of PDK1 and Akt but not PI3-K in cav-1-stimulated cells compared to control cells. We subsequently found that cav-1 interacts with and inhibits serine/threonine protein phosphatases PP1 and PP2A through scaffolding domain binding site interactions. Deletion of the cav-1 scaffolding domain significantly reduces phosphorylated Akt and cell viability compared with wild-type cav-1. Analysis of potential substrates for PP1 and PP2A revealed that cav-1-mediated inhibition of PP1 and PP2A leads to increased PDK1, Akt, and ERK1/2 activities. We demonstrate that increased Akt activities are largely responsible for cav-1-mediated cell survival using dominant-negative Akt mutants and specific inhibitors to MEK1/MEK and show that cav-1 increases the half-life of phosphorylated PDK1 and Akt after inhibition of PI3-K by LY294002. We further demonstrate that cav-1-stimulated Akt activities lead to increased phosphorylation of multiple Akt substrates, including GSK3, FKHR, and MDM2. In addition, overexpression of cav-1 significantly increases translocation of phosphorylated androgen receptor to nucleus. Our studies therefore reveal a novel mechanism of Akt activation in prostate cancer and potentially other malignancies.Prostate cancer remains the second leading cause of cancer mortality among American males. The predominant reason for such high and persistent mortality is the lack of curative therapies for androgen-resistant metastatic disease. It is critical to elucidate the molecular mechanisms that underlie the ultimate androgen-resistant state of prostate cancer and to develop effective therapies for this condition.Previously, Yang et al. reported that caveolin-1 (cav-1) levels were elevated in metastatic mouse and human prostate cancer (85). cav-1 is a major component of caveolae, flask-shaped membrane invaginations which are involved in multiple cellular processes, including the regulation and transportation of cellular cholesterol and lipids, clathrin-independent endocytosis, and signal transduction (24,27,60,62,66). The participation of cav-1 in these critical pathways involves the interaction of cav-1 with a relatively large number of molecules in either a scaffolding binding-dependent or -independent manner (41, 63). The wide spectrum of molecular interactions involving cav-1 is consistent with important, context-dependent roles for cav-1 in signal transduction, molecular transport, and other regulatory activities.The biological functions of cav-1 in cancer are complex, multifaceted, and somewhat controversial (42,55,72,73). Numerous experimental results indicate that cav-1 is a growth suppressor (14,17,35). Some investigators have assert...

Our previous finding of RTVP1 (GLIPR1) as a p53 target gene with tumor suppressor functions prompted us to initiate a genome-wide sequence homology search for RTVP1/GLIPR1-like (GLIPR1L) genes. In this study we report the identification and characterization of a novel p53 target gene cluster that includes human RTVP1 (hRTVP-1) together with two GLIPR1L genes (GLIPR1L1 and GLIPR1L2) on human chromosome 12q21 and mouse Rtvp1 (mRTVP-1 or Glipr1) together with three Glipr1-like (Glipr1l) genes on mouse chromosome 10D1. GLIPR1L1 has two and GLIPR1L2 has five differentially spliced isoforms. Protein homology search revealed that hRTVP-1 gene cluster members share a high degree of identity and homology. GLIPR1L1 is testis-specific, whereas GLIPR1L2 is expressed in different types of tissues, including prostate and bladder. Like hRTVP-1, GLIPR1L1 and GLIPR1L2 are p53 target genes. The similarities of these novel p53 target gene cluster members in protein structure and their association with p53 suggest that these genes may have similar biological functions.

The control technology for mining subsidence is the main research area of mining subsidence. Its objective is to study and select mining methods appropriate for reducing the surface and overlying strata subsidence and protecting the surface structures. Referring to the analysis of references, the control technology for mining subsidence is discussed from several aspects including backfill mining method, partial mining method, backfill the collapsed cavities in overlying strata, harmonized mining method and 3-step mining method, stripping mining-goaf grouting, and backfill-strip pillar mining. The developing trend of the control technology is also prospected.