Search

Supplementary Figure S2. Genetic tools used for dissecting Il6/Stat3/Myc signaling. (A) Scheme of conditional alleles and PCR primers used for assessing the recombination of Pten/ Trp53 genes. (B) Senescence-specific ß-gal staining is detected after Pten loss but not after Pten/Trp53 co-deletion. Scale Bar, 200 μm.

Supplementary Figure S1. Copy Number Alteration analysis of human prostate cancer confirms loss of PTEN and TP53 genes as a genetic hallmark of metastatic prostate cancer. (A) Co-deletion frequency for PTEN and TP53 in metastatic and primary prostate cancer samples. (B) Co-deletion frequency for PTEN and TP53 in metastatic and primary prostate cancer samples. (C) Co-deletion frequency for PTEN and TP53 in metastatic prostate cancer samples . (D) Gene maps of the conditional alleles used for ablation of Pten/ Trp53 genes and activation of tdTomato. Cre leads to recombination of loxP sites in the Pten/Trp53 genes and excision of a STOP cassette that leads to activation of the fluorescence protein tdTomato. (E) Analysis of tdTomato-positive cells using Guava flow cytometry system show that AdCre leads to activation of tdTomato in over 95% percent of cells without the need for selection. (F) Activation of tdTomato can be easily visualized using fluorescence microscopy.

Supplementary Figure S7. Pathway to Pten/ Trp53 deficient prostate metastasis and therapy resistance. Pten-loss triggers PIP3 signaling to activate AKT, which prompts activation of the p53/ p21/ p16 tumor suppressors and senescence arrest. Suppression and loss of p53 in this context results in cell proliferation and Il6 secretion. Il6 signals both auto and paracrine to activate Myc via the Jak/Stat pathway. Myc induces the Phlpp2 phosphatase which creates a negative feedback loop by dampening Akt activation. Metastases (and castration-resistant tumors) select for increased Myc expression (and gene amplification, and Akt inactivation, demonstrating that Myc supersedes the need for Akt in lethal prostate cancer.

Supplementary Figure S3. Tools used for targeting of Il6 and Stat3. (A) Il6 neutralizing antibody specifically decreases the proliferation of Pten/ Trp53 deficient primary MEFs. ANOVA, Dunnett's post-hoc test, **p

Supplementary Figure S4. Activation of Stat3/Myc signaling is specific to Ptenpc-/-; Trp53pc-/-prostate and leads to stromal expansion. (A) H&E analysis of prostates from all studied genotypes reveals massive stromal expansion after co-deletion of Pten and Trp53. IHC analysis confirms stromal pStat3/ Myc activation specifically in Ptenpc-/-; Trp53pc-/- prostate. Note that pAkt activation is restricted to gland, consistent with triggering paracrine Il6/Stat3/Myc activation. Scale Bars, 100 μm. (B) Pten is present in the stroma of Ptenpc-/-; Trp53pc-/- prostates confirming that the expansion of stroma is not driven by spurious Pten/Trp53 recombination. (C) Proliferation in the Ptenpc-/- glands correlates with Akt activation, in contrast to Ptenpc-/-; Trp53pc-/- glands, where it correlates with Stat3/ Myc staining.

Supplementary Figure S6. Ar expression in primary and metastatic tumors. (A) IHC analysis of the Ar status in RapidCaP lesions shows no significant Ar staining (left panel) while most prostate glands show strong nuclear Ar staining. (B) The wild type and mutant prostates from Probasin-Cre animals show strong Ar staining.

Supplementary Figure Legends from MYC Drives Pten/Trp53-Deficient Proliferation and Metastasis due to IL6 Secretion and AKT Suppression via PHLPP2

Loss of DNA copy number at the short arm of chromosome 3 is one of the most common genetic changes in human lung cancer, suggesting the existence of one or more tumor suppressor genes (TSG) at 3p. To identify most frequently deleted regions and candidate TSGs within these regions, a recently developed single-nucleotide polymorphism (SNP)-mass spectrometry-genotyping (SMSG) technology was applied to investigate the loss of heterozygosity (LOH) in 30 primary non–small-cell lung cancers. A total of 386 SNP markers that spanned a region of 70 Mb at 3p, from 3pter to 3p14.1, were selected for LOH analysis. The average intermarker distance in the present study is ∼180 kb. Several frequently deleted regions, including 3p26.3, 3p25.3, 3p24.1, 3p23, and 3p21.1, were found. Several candidate TSGs within these frequently detected LOH regions have been found, including APG7L at 3p25.3, CLASP2 at 3p23, and CACNA2D3 at 3p21.1. This study also showed that SMSG technology is a very useful approach to rapidly define the minimal deleted region and to identify target TSGs in a given cancer. (Cancer Res 2006; 66(8): 4133-8)

Supplementary Table 2 from High-throughput Loss-of-Heterozygosity Study of Chromosome 3p in Lung Cancer Using Single-Nucleotide Polymorphism Markers

Supplementary Table 1 from High-throughput Loss-of-Heterozygosity Study of Chromosome 3p in Lung Cancer Using Single-Nucleotide Polymorphism Markers

Mixed [C8bet]Br/[C4mim][NTf2] ionic liquids were used as a new extraction system to extract Pd(II) from multimetal-ion solutions. The separation factors KPd/M (M: Cu, Fe, Ni, Zn, Co) are greater than 103. Thiourea was found to be an effective stripping agent. After three cycles, the recovery efficiency was higher than 91.0%. Direct electrodeposition of palladium from the mixed ionic liquid phase was also studied. The Pd(II) complex in [C8bet]Br/[C4mim][NTf2] system was studied by cyclic voltammetry at 348 K. The results indicate the existence of three types of Pd(II) complex in the [C8bet]Br/[C4mim][NTf2] system, leading to three reductive waves. The reduction of Pd(II) to Pd(0) in this system is irreversible. A uniform black coating was obtained by constant-potential deposition at −1.7 V on a nickel foil, confirmed to be palladium metal by energy-dispersive spectrometry, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy analyses. After three cycles of continuous extraction–electrodeposition, over 90.0% of palladium was recovered.

Artificial intelligence (AI) has shown great potential in wireless communications. AI-empowered communication algorithms have beaten many traditional algorithms through simulations. However, the existing works just use the simulated datasets to train and test the algorithms, which can not represent the power of AI in practical communication systems. Therefore, Peng Cheng Laboratory holds an AI competition, National Artificial Intelligence Competition (NAIC): AI+wireless communications, in which one of the topics is AI-empowered channel feedback system design using practical measurements. In this paper, we give a baseline neural network design, QuanCsiNet, for this competition, and the details of the channel measurements. QuanCsiNet shows excellent performance on channel feedback and the complexity of the neural networks is also given.

Since the late 1990s, the trend of plastic waste shipment from developed to developing countries has been increasing. In 2017, China announced an unprecedented ban on its import of most plastic waste, resulting in a sharp decline in global plastic waste trade flow and changes in the treatment structure of countries, whose impacts on global environmental sustainability are enormous but yet unexamined. Here, through the life cycle assessment (LCA) method, we quantified the environmental impacts of changes in the flow patterns and treatment methods of 6 types of plastic waste in 18 countries subsequent to the ban. In the short term, the ban significantly improved four midpoint indicators of environmental impact, albeit contributed to global warming. An annual saving of about 2.35 billion euros of eco-cost was realized, which is equivalent to 56% of plastic waste global trade value in 2017. To achieve global environmental sustainability in the long run, countries should gradually realize the transition from export to domestic management, and from landfill to recycling, which would realize eco-costs savings of about 1.54–3.20 billion euros., China announced a ban on its import of most plastic waste in 2017, resulting in an impact on global environmental sustainability. Here the authors quantify the environmental impacts of changes in the flow patterns and treatment methods of 6 types of plastic waste in 18 countries subsequent to the ban.

The increasingly serious environmental problems make it urgent to develop a new type of sustainable green material which can degrade pollutants and monitor human health. However, the traditional preparation methods are frequently limited by tedious operations, high-energy consumption, and massive pollution. Herein, we present a facile and green method for preparation of MnO2 nanoflakes mediated by macrocyclic molecule calix[8]arene. The MnO2 nanoflakes in situ grew on the preformed gold nanoparticles, forming an impressive core–shell Au@MnO2 flake-like nanocomposite. The catalytic properties of Au@MnO2 composite for reduction of 4-NP and degradation of MB were 2.4 and 187 times better than commercial Pd/C, respectively. Meanwhile, the as-synthesized Au@MnO2 nanocomposite exhibited specially excellent sensitivity and selectivity for detection of GSH with a limit of detection (LOD) of 0.11 μM. The core–shell nanostructured Au@MnO2 shows great potential value for the sustainable development of the environmen...

In this study, four novel functionalized ionic liquids ([C4mim][DDTC], [C5mim][DDTC], [C6mim][DDTC], and [BMPip][DDTC]) were synthesized and used for the selective extraction of Pd(II) from an HCl medium containing Pt(IV), Pd(II), and Rh(III). The extraction mechanism was investigated using Job’s plots, UV–Vis, SXRD, and MS analysis. A mechanistic investigation revealed the formation of hydrophobic extraction complexes Pd(DDTC)2 and PdClDDTC via coordination between [DDTC]− and Pd(II). In addition, the solubility and polarity of the solutes were investigated using DFT calculations to determine the optimal extractant and diluent. From the results of the theoretical analysis, [C5mim][DDTC]/CHCl3 was selected as the optimum system for the selective extraction of Pd(II). The effects that factors have on Pd(II) extraction, including temperature, [C5mim][DDTC] amount, HCl concentration, and O/A ratio, were investigated and optimized using single-factor and response surface experiments. Under the optimized conditions, Pd(II) extraction efficiencies were higher than 99%, and the separation factors (βPd(II)/Pt(IV) and βPd(II)/Rh(III)) were greater than 104. After extraction, Pd and Rh were directly recovered from the organic and aqueous phases via photocatalytic reduction, respectively. TEM, XPS, and PXRD results revealed that the resulting nanoparticles were Rh(0) or Pd(0). The recovery of Pd and Rh exceeded 95%. Overall, a simple hydrometallurgical process with low reagent consumption was developed to yield nanometer-scale Pd(0) and Rh(0) from simulated secondary resource leaching solutions.

In this study, based on a cyano-functionalized ionic liquid, 1-nitrile-1-octylpyrrole bromide ([C8Y3Pr]Br), a [C8Y3Pr]Br/cyclohexane/tributyl phosphate (TBP)/NaCl microemulsion system was constructed and used for the extraction of Pd(II) and preparation of Pd nanoparticles from multimetal solutions. The key extraction parameters including vibration time, [C8Y3Pr]Br concentration, phase ratio (RW/O), and HCl concentration were evaluated. Compared with other ionic-liquid microemulsion systems, the cyano-functionalized ionic liquid [C8Y3Pr]Br microemulsion system showed excellent extraction performance for Pd(II). Almost all Pd(II) was extracted (>98.0%) from a multimetal solution using the microemulsion system, while the separation factors (βPd/M) of [C8Y3Pr]Br-based microemulsions for Pd(II) with Cu2+, Fe3+, Ni2+, Zn2+, Co2+, and Mg2+ exceeded 1.0 × 103. The mechanism extracting Pd(II) using [C8Y3Pr]Br was confirmed to be an anion-exchange reaction via Job’s method, spectral analysis (UV, FTIR), and DFT calculations. Alcohols and hydrazine hydrate were used as demulsifiers, and Pd nanoparticles were directly obtained from the microemulsion phase. The Pd nanoparticles were identified by TEM, XPS, and XRD analyses. The chemical structures of extracted species based on the microemulsion system and the mechanism of demulsification of alcohols were studied. Thus, an effective new process was developed in this study for the direct preparation of Pd nanoparticles from mixed metal solutions via solvent extraction.

Developing an efficient method to recover and reuse soil-base lead (Pb) poses significant challenges. Herein, we designed a remediation method to achieve the dual goal of separating and reusing Pb from soil based on Bacillus megaterium-secreted surfactin with pH-response. Under weakly alkaline, B. megaterium-secreted surfactin efficiently captured Pb(II) from soil and also converted it into biological Pb/PbO nanoparticles (bio-Pb/PbO NPs). Further, surfactin’s sensitivity to pH enables bio-Pb/PbO NPs to be readily separated from the soil through simple pH adjustments. The highest yield of bio-Pb/PbO NPs (77.54%) was achieved at an initial concentration of 1 mg/g Pb(II). The recovered bio-Pb/PbO NPs showed a mesoporous structure and an average size of ~47 nm. More importantly, bio-Pb/PbO NPs exhibited highly efficient catalytic activity for the hydrogen evolution reaction in 1 M KOH. These results demonstrated that this method efficiently recovered and converted Pb into high value-added NPs, and was thereby a sustainable and feasible technique for Pb(II) recovery and reuse. As such, this methodology offers a new, efficient, and practical approach for sustainable remediation of heavy metal contamination in soils.

Although phosphonium-based ionic liquids (ILs) have become popular green solvents for the separation of precious metals, these solvents have not been used thus far to recover Pd(II) from alkaline cyanide solutions. In this study, three novel phosphonium-based ILs, viz. tributyl(2-ethylhexyl) phosphonium bromide (TBEHPB), trioctyl (2-ethylhexyl) phosphonium bromide (TOEHPB), and trioctyl undecyl phosphonium bromide (TOUPB), were synthesized, respectively, and these ILs were used for the recovery of Pd(CN)42− for the first time. With the increase in the length of the alkyl chain in the phosphonium cation, the extraction percentage of Pd(II) increased. Under optimum conditions (i.e., contact time of 5 min, pH of 10.5, and temperature of 298 K), the TOUPB system exhibited a Pd(II) extraction percentage of greater than 99.0%. Furthermore, the TOUPB system exhibited excellent selectivity for Pd(II) in a mixed solution (separation factors of βPd/Fe and βPd/Co were greater than 2.0 × 103). The Pd(II) recovery percentage was still greater than 90.0% after five consecutive extraction-stripping cycles. The Job’s method, infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy, and UV–vis spectroscopy revealed that the extraction mechanism is ion exchange. The supramolecular structure of the extraction complex was established on the basis of density functional theory (DFT) calculations and Karl Fischer titration, and the extraction mechanism was further described at the molecular structure level. This study provides a new process for recovering Pd(II) from an alkaline cyanide medium.

Reduced PTEN protein is linked to tumorigenesis. Here, Chen et al. show that the nuclear transport receptor Importin-11 separates PTEN from degradation machinery. IPO11 mutant mice exhibit PTEN degradation, lung adenocarcinoma, and prostate neoplasia. In human prostatectomy patients, IPO11 status predicts disease recurrence and metastasis., 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.

BACKGROUND Thus far, separation and recovery of Pd(CN)42- and Pt(CN)42- from cyanide liquors have not been reported. In this study, the process of co-extracting and separating Pd(II) and Pt(II) over Fe(III), Cu(I), Co(III), and Ni(I) from alkaline cyanide liquors was investigated. RESULTS The results showed that almost all Pd(II) and Pt(II) (>98.0%) could be simultaneously extracted by phenoxyethyl dimethyl palmitylammonium bromide (PDPB), whereas Fe(III), Cu(I), Co(III), and Ni(I) was below 3.0% under optimum conditions. Furthermore, Pd(CN)42- and Pt(CN)42- were separated and recovered by the two-step stripping process. First, Pd(CN)42- in mixed organic phase was stripped by a 2.0 mol L−1 ammonium thiocyanate solution. The stripping percentage of Pd(CN)42- was >98%, whereas the stripped Pt(CN)42- was below 1%. Second, more than 97.5% Pt(CN)42- in the loaded organic phase could be stripped using 1.0 mol L−1 thiodiglycol solution. Recovery ratios for both Pd(II) and Pt(II) were above 95%. The organic phase could be reused for at least 6 cycles of extraction–stripping processes. The mechanisms of extraction reaction were deduced to be ion-association mechanisms. CONCLUSION The process could be applied for extracting and separating palladium and platinum from the cyanide leaching liquor of the flotation concentrate. © 2016 Society of Chemical Industry

A novel functional ion-exchange/adsorption metal organic resin (MOR), TEBAC-HKUST-1, was prepared and characterized. Ethanedithiol was used as the grafting agent to introduce thiol groups onto HKUST-1, and 4-vinylbenzyl chloride was then grafted onto SH-HKUST-1 using thiol groups. Finally, the quaternary ammonium functional group was immobilized onto the carrier by performing a quaternization reaction. The structure and property of TEBAC-HKUST-1 MOR were characterized by TGA, N2 adsorption&ndash, desorption, FTIR, SEM, and XRD. TEBAC-HKUST-1 MOR was used to remove metal cyanide complexes from wastewater. The adsorption was rapid, and the metal cyanide complexes including Pt(CN)42&minus, Co(CN)63&minus, Cu(CN)32&minus, and Fe(CN)63&minus, were removed in 30 min. TEBAC-HKUST-1 MOR exhibited a high stability in neutral and weak basic aqueous solutions. Furthermore, Pt(II) could be efficiently recovered through two-step elution. The recovery rate of Pt(II) for five cycles were over 92.0% in the mixture solution containing Pt(CN)42&minus, The kinetic data were best fitted with the pseudo second-order model. Moreover, the isothermal data were best fitted with the Langmuir model. The thermodynamic results show that the adsorption is a spontaneous and exothermic process. TEBAC-HKUST-1 MOR not only exhibited excellent ability for the rapid removal of metal cyanide complexes, but also provided a new idea for the extraction of noble metals from cyanide-contaminated water.

In this study, five new imidazolium ionic liquids (ILs) were synthesized, and their efficiencies toward the precipitation of PtCl62− in HCl media were evaluated. The prepared compounds were identified as 1-alkyl-3-propylimidazolium bromide ([CnPIm]Br, n = 12, 14, and 16), 1-tetradecyl-2-aminoethylimidazolium bromide ([C14PImNH2]Br), and 1-tetradecyl-3-butylimidazolium bromide ([C14PIm]Br). FT-IR, 1H NMR, and continuous variation method analysis were used to establish the ion-exchange model of Pt(IV) precipitation. To extract Pt(IV) from mixed metal solutions, and a novel mixed-ILs system was obtained through the dissolution of 1-tetradecyl-3-propylimidazolium bromide ([C14PIm]Br) in hydrophobic ILs ([C8MIm][PF6]). The mixed-ILs ([C14PIm]Br/[C8MIm][PF6]) exhibited excellent extraction efficiency compared to single [C8MIm][PF6]. Also, Pt(IV) ions were selectively separated from mixed metal solutions containing Rh(III), Fe3+, Ni2+, Cu2+, and Zn2+ metal ions. The separation factor βPt/M (M: Fe, Ni, Cu, Zn, or Rh) was above 105 for all systems. The optimal potentiostatic deposition voltage of Pt was estimated to −1.75 V. Direct electrodeposition from ILs containing [C14PIm]Br/[C8MIm][PF6] with Pt(IV), more than 97% of Pt(IV) was reduced to Pt(0) on the copper cathode, while the system could also be regenerated for PtCl62− extraction. Surface characterization techniques like SEM, TEM, and XPS identified the deposited silver-grey films on cathode surfaces as Pt metal with metallic luster.

Metal-cyanide complexes are hazardous and toxic pollutants that can accumulate in organisms, and their natural degradation is difficult. These complexes are primarily present in alkaline wastewater effluents, and an effective technique for their removal must be developed. Herein, we have successfully synthesized a novel quaternary ammonium-functionalized Zr4+ metal-organic resin (MOR) (H16[Zr6O16(MPATP)4]Cl8·xH2O, MPATP = 2-((1-methylpyridin-1-ium-2-ylmethyl)amino)-terephthalic acid), which we refer to as MOR-2-QAS. With alkali resistance, high surface area, and high anion exchange capacity, it acts by introducing positively charged pyridine into the organic ligand. The experimental results indicate that MOR-2-QAS becomes rapidly attached and efficiently removes Pt(CN)42−, Pd(CN)42−, Co(CN)63−, and Fe(CN)63−. Valuable metals (Pt(II) and Pd(II)) can be effectively recovered from the simulated wastewater containing four-component cyanide complexes via the two-step elution process. The recovery efficiency of Pt(II) and Pd(II) was higher than 90.0% after three adsorption-desorption cycles. The adsorption mechanism, which proceeded via ionic association (ion-exchange) and complied with the minimum surface charge density experiential principle, was confirmed using density functional theory. This study provides ideas for developing efficient and stable MORs to enable the simultaneous removal of multiple metal–cyanide complexes and recovery of valuable metals.

In this study, quaternary-ammonium-functionalized metal&ndash, organic frameworks (MOFs) Et-N-Cu(BDC-NH2)(DMF), were prepared, characterized, and applied for the highly effective removal of metal cyanide complexes, including Pd(CN)42&minus, Co(CN)63&minus, and Fe(CN)63&minus, Batch studies were carried out, and the maximum adsorption capacities of Pd(II), Co(III), and Fe(III) reached 172.9, 101.0, and 102.6, respectively. Adsorption was rapid, and equilibrium was established within 30 min. Et-N-Cu(BDC-NH2)(DMF) exhibited high thermal and chemical stability. Furthermore, absorbed Pd(CN)42&minus, was selectively recovered by two-step elution. First, Co(CN)63&minus, were eluted with a 1.5 mol L&minus, 1 KCl solution. Elution rates of Co(CN)63&minus, were greater than 98.0%, whereas the elution percentage of Pd(CN)42&minus, was less than 2.0%. Second, &gt, 97.0% Pd(CN)42&minus, on the loaded MOFs was eluted using a 2.0 mol L&minus, 1 KI solution. The recovery rate of Pd(CN)42&minus, was greater than 91.0% after five testing cycles. Adsorption isotherms, kinetics models, and adsorption thermodynamics of Pd(CN)42&minus, on Et-N-Cu(BDC-NH2) (DMF) were also systematically investigated. The Et-N-Cu(BDC-NH2) (DMF) absorbent exhibited a rapid, excellent ability for the adsorption of metal cyanide complexes.

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.

We have recently recapitulated metastasis of human PTEN/TP53–mutant prostate cancer in the mouse using the RapidCaP system. Surprisingly, we found that this metastasis is driven by MYC, and not AKT, activation. Here, we show that cell–cell communication by IL6 drives the AKT–MYC switch through activation of the AKT-suppressing phosphatase PHLPP2, when PTEN and p53 are lost together, but not separately. IL6 then communicates a downstream program of STAT3-mediated MYC activation, which drives cell proliferation. Similarly, in tissues, peak proliferation in Pten/Trp53–mutant primary and metastatic prostate cancer does not correlate with activated AKT, but with STAT3/MYC activation instead. Mechanistically, MYC strongly activates the AKT phosphatase PHLPP2 in primary cells and prostate cancer metastasis. We show genetically that Phlpp2 is essential for dictating the proliferation of MYC-mediated AKT suppression. Collectively, our data reveal competition between two proto-oncogenes, MYC and AKT, which ensnarls the Phlpp2 gene to facilitate MYC-driven prostate cancer metastasis after loss of Pten and Trp53. Significance: Our data identify IL6 detection as a potential causal biomarker for MYC-driven metastasis after loss of PTEN and p53. Second, our finding that MYC then must supersede AKT to drive cell proliferation points to MYC inhibition as a critical part of PI3K pathway therapy in lethal prostate cancer. Cancer Discov; 5(6); 636–51. ©2015 AACR. This article is highlighted in the In This Issue feature, p. 565

PTEN is proposed to function at the plasma membrane, where receptor tyrosine kinases are activated. However, the majority of PTEN is located throughout the cytoplasm. Here, we show that cytoplasmic PTEN is distributed along microtubules, tethered to vesicles via phosphatidylinositol 3-phosphate (PI(3)P), the signature lipid of endosomes. We demonstrate that the non-catalytic C2 domain of PTEN specifically binds PI(3)P through the CBR3 loop. Mutations render this loop incapable of PI(3)P binding and abrogate PTEN-mediated inhibition of PI 3-kinase/AKT signaling. This loss of function is rescued by fusion of the loop mutant PTEN to FYVE, the canonical PI(3)P binding domain, demonstrating the functional importance of targeting PTEN to endosomal membranes. Beyond revealing an upstream activation mechanism of PTEN, our data introduce the concept of PI 3-kinase signal activation on the vast plasma membrane that is contrasted by PTEN-mediated signal termination on the small, discrete surfaces of internalized vesicles.

PTEN is thought to function at the plasma membrane where receptor tyrosine kinases activate PI 3-Kinases. Yet the majority of PTEN is located throughout the cytoplasm so that only a fraction of PTEN could be actively suppressing PI 3-K signaling at any time. Here we show that cytoplasmic PTEN is distributed along microtubules, tethered to vesicles via interaction with phosphatidylinositol 3- phosphate (PI(3)P), the signature lipid of endosomes. We demonstrate that the C2 domain of PTEN specifically binds PI(3)P via the CBR3-loop. Mutations that render the CBR3-loop incapable of PI(3)P binding abrogate PTEN function in cells but not in vitro. The loss-of-function in cells is rescued by fusion of the canonical PI(3)P vesicle targeting domain, FYVE, to CBR3-loop mutant PTEN, demonstrating the functional relevance of PTEN activity on endosomal membranes. These findings introduce an entirely unexpected site of action of the PTEN tumor suppressor. Furthermore, they introduce the concept of PI 3-K signal activation over the vast surface of the plasma membrane that is contrasted by PTEN-mediated signal termination on the discretely sized and much smaller surfaces of endocytic vesicles. Implications of these results for cancer signaling and growth control will be discussed. Note: This abstract was not presented at the meeting. Citation Format: Adam Naguib, Gylua Bencze, Hyejin Cho, Wu Zheng, Ante Tocilj, Elad Elkayam, Christopher R Faehnle, Nadia Jaber, Christopher Pratt, Muhan Chen, Wei-Xing Zong, Michael S Marks, Leemor Joshua-Tor, Darryl J Pappin, Lloyd C. Trotman. PTEN function is controlled by recruitment to cytoplasmic vesicles. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-063. doi:10.1158/1538-7445.AM2015-LB-063

The sporadic transition from indolent to metastatic disease is a hallmark of prostate cancer (PC) and frequently involves deletion of PTEN and TP53. We recently recapitulated metastasis of Pten/ Trp53-mutant PC in mouse using the RapidCaP system and surprisingly, we found that it is driven by Myc, rather than Akt activation. Here, we show that cell-cell communication by Il6 drives this Akt-Myc switch through activation of the Akt-inactivating phosphatase Phlpp2. Primary cells revealed that loss of Pten/ Trp53 triggers secretion of the Il6 cytokine when these genes are deleted together, but not separately. Il6 then communicates a downstream program of Stat3-mediated Myc activation, which drives cell proliferation. Abrogation of Myc activity by Myc inhibition with the JQ1 bromodomain inhibitor, Myc-RNAi, and Myc-CRISPR/ Cas9 approaches inhibited proliferation. We validated these findings in vivo, where peak proliferation in Pten/ Trp53 mutant primary and metastatic PC did not correlate with activated Akt, but with Stat3/ Myc activation instead. Most notably, we found that Myc strongly activates the Akt phosphatase Phlpp2 in primary cells and RapidCaP metastasis, and showed genetically that Phlpp2 is essential for dictating proliferation and Myc-mediated suppression of Akt. Collectively, our data reveal competition between two proto-oncogenes: Myc and Akt, which ensnarls the Phlpp2 gene to facilitate Myc-driven metastasis. Citation Format: Dawid G. Nowak, Hyejin Cho, Tali Herzka, Victoria M.Y. Wang, Serif Senturk, Daniel V. DeMarco, David Ding, Christof Fellmann, Tumas Beinortas, David Kleinman, Kaitlin Watrud, Muhan Chen, John E. Wilkinson, Mireia Castillo-Martin, Carlos Cordon-Cardo, Brian D. Robinson, Lloyd C. Trotman. Myc drives Pten/ p53-deficient proliferation and metastasis due to Il6-secretion and Akt-suppression via Phlpp2. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2258. doi:10.1158/1538-7445.AM2015-2258