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Phosphatase and tensin homologue (PTEN) protein levels are critical for tumor suppression. However, the search for a recurrent cancer-associated gene alteration that causes PTEN degradation has remained futile. In this study, we show that Importin-11 (Ipo11) is a transport receptor for PTEN that is required to physically separate PTEN from elements of the PTEN degradation machinery. Mechanistically, we find that the E2 ubiquitin-conjugating enzyme and IPO11 cargo, UBE2E1, is a limiting factor for PTEN degradation. Using in vitro and in vivo gene-targeting methods, we show that Ipo11 loss results in degradation of Pten, lung adenocarcinoma, and neoplasia in mouse prostate with aberrantly high levels of Ube2e1 in the cytoplasm. These findings explain the correlation between loss of IPO11 and PTEN protein in human lung tumors. Furthermore, we find that IPO11 status predicts disease recurrence and progression to metastasis in patients choosing radical prostatectomy. Thus, our data introduce the IPO11 gene as a tumor-suppressor locus, which is of special importance in cancers that still retain at least one intact PTEN allele. [ABSTRACT FROM AUTHOR]

Background: Amplification of 3q26 is one of the most frequent genetic alterations in many human malignancies. Recently, we isolated a novel oncogene eIF-5A2 within the 3q26 region. Functional study has demonstrated the oncogenic role of eIF-5A2 in the initiation and progression of human cancers. In the present study, we aim to investigate the physiological and pathological effect of eIF-5A2 in an eIF-5A2 transgenic mouse model. Methods: An eIF-5A2 transgenic mouse model was generated using human eIF-5A2 cDNA. The eIF-5A2 transgenic mice were characterized by histological and immunohistochemistry analyses. The aging phenotypes were further characterized by wound healing, bone X-ray imaging and calcification analysis. Mouse embryo fibroblasts (MEF) were isolated to further investigate molecular mechanism of eIF-5A2 in aging. Results: Instead of resulting in spontaneous tumor formation, overexpression of eIF-5A2 accelerated the aging process in adult transgenic mice. This included decreased growth rate and body weight, shortened life span, kyphosis, osteoporosis, delay of wound healing and ossification. Investigation of the correlation between cellular senescence and aging showed that cellular senescence is not required for the aging phenotypes in eIF-5A2 mice. Interestingly, we found that activation of eIF-5A2 repressed p19 level and therefore destabilized p53 in transgenic mouse embryo fibroblast (MEF) cells. This subsequently allowed for the accumulation of chromosomal instability, such as errors in cell dividing during metaphase and anaphase. Additionally, a significantly increase in number of aneuploidy cells (p < 0.05) resulted from an increase in the incidences of misaligned and lagging chromosomal materials, anaphase bridges, and micronuclei in the transgenic mice. Conclusion: These observations suggest that eIF-5A2 mouse models could accelerate organismal aging by increasing chromosome instability. [ABSTRACT FROM AUTHOR]

Background: Amplification of 1q21 is the most frequent genetic alteration in hepatocellular carcinoma (HCC), which was detected in 58-78% of primary HCC cases by comparative genomic hybridization (CGH). Using chromosome microdissection/hybrid selection approach we recently isolated a candidate oncogene CHD1L from 1q21 region. Our previous study has demonstrated that CHD1L had strong oncogenic ability, which could be effectively suppressed by siRNA against CHD1L. The molecular mechanism of CHD1L in tumorigenesis has been associated with its role in promoting cell proliferation. Methodology/Principal Findings: To further investigate the in vivo oncogenic role of CHD1L, CHD1L ubiquitous-expression transgenic mouse model was generated. Spontaneous tumor formations were found in 10/41 (24.4%) transgenic mice, including 4 HCCs, but not in their 39 wild-type littermates. In addition, alcohol intoxication was used to induce hepatocyte pathological lesions and results found that overexpression of CHD1L in hepatocytes could promote tumor susceptibility in CHD1L-transgenic mice. To address the mechanism of CHD1L in promoting cell proliferation, DNA content between CHD1L-transgenic and wildtype mouse embryo fibroblasts (MEFs) was compared by flow cytometry. Flow cytometry results found that CHD1L could facilitate DNA synthesis and G1/S transition through the up-regulation of Cyclin A, Cyclin D1, Cyclin E, CDK2, and CDK4, and down-regulation of Rb, p27Kip1, and p53. Conclusion/Significance: Taken together, our data strongly support that CHD1L is a novel oncogene and plays an important role in HCC pathogenesis [ABSTRACT FROM AUTHOR]

Metastatic prostate cancer commonly presents with targeted, bi-allelic mutations of the PTEN and TP53 tumor suppressor genes. In contrast, however, most candidate tumor suppressors are part of large recurrent hemizygous deletions, such as the common chromosome 16q deletion, which involves the AKT-suppressing phosphatase PHLPP2. Using RapidCaP, a genetically engineered mouse model of Pten/Trp53 mutant metastatic prostate cancer, we found that complete loss of Phlpp2 paradoxically blocks prostate tumor growth and disease progression. Surprisingly, we find that Phlpp2 is essential for supporting Myc, a key driver of lethal prostate cancer. Phlpp2 dephosphorylates threonine-58 of Myc, which renders it a limiting positive regulator of Myc stability. Furthermore, we show that small-molecule inhibitors of PHLPP2 can suppress MYC and kill PTEN mutant cells. Our findings reveal that the frequent hemizygous deletions on chromosome 16q present a druggable vulnerability for targeting MYC protein through PHLPP2 phosphatase inhibitors. [ABSTRACT FROM AUTHOR]

Conventional separation methods are not suitable for recovering palladium present in low concentrations in ore leaching solutions. In this study, a novel isopentyl sulfide (S201)-impregnated α-MnO2 nanorod adsorbent (BISIN) was prepared, characterized, and applied for the selective adsorption and separation of palladium from the leaching liquor of ores. Batch studies were carried out, and the main adsorption parameters were systematically investigated, in addition to the relevant thermodynamic parameters, isotherms, and kinetic models. The thermodynamic parameters reflected the endothermic and spontaneous nature of the adsorption. Moreover, the experimental results indicated that the Langmuir isotherm model fits the palladium adsorption data well and the adsorption was well described by the pseudo-second-order kinetic model. The main adsorption mechanisms of palladium were elucidated at the molecular level by X-ray crystal structure analysis. Thiourea was found to be an excellent desorption agent, and the palladium-thiourea complex was also confirmed by X-ray crystal structure analysis. The results indicated that almost all of the Pd(II) (>99.0%) is adsorbed on BISIN, whereas less than 2% of the adsorbed Pt(IV), Fe3+, Cu2+, Ni2+, and Co2+ is observed under the optimum conditions. The proposed method can be used for the efficient adsorption and separation of palladium from the leaching liquor of ores. [ABSTRACT FROM AUTHOR]