A Fault Detection Method Based on CPSO-Improved KICA.

In view of the randomness in the selection of kernel parameters in the traditional kernel independent component analysis (KICA) algorithm, this paper proposes a CPSO-KICA algorithm based on Chaotic Particle Swarm Optimization (CPSO) and KICA. In CPSO-KICA, the maximum entropy of the extracted independent component is first adopted as the fitness function of the PSO algorithm to determine the optimal kernel parameters, then the chaotic algorithm (CO) is used to avoid the local optimum existing in the traditional PSO algorithm. Finally, this proposed algorithm is compared with Weighted KICA (WKICA) and PSO-KICA with Tennessee Eastman Process (TEP) as the benchmark. Simulation results show that the proposed algorithm can determine the optimal kernel parameters and perform better in terms of false alarm rates (FAR), detection latency (DL) and fault detection rates (FDR).

A Preexisting Rare PIK3CAE545K Subpopulation Confers Clinical Resistance to MEK plus CDK4/6 Inhibition in NRAS Melanoma and Is Dependent on S6K1 Signaling.

Combined MEK and CDK4/6 inhibition (MEKi + CDK4i) has shown promising clinical outcomes in patients with NRAS-mutant melanoma. Here, we interrogated longitudinal biopsies from a patient who initially responded to MEKi + CDK4i therapy but subsequently developed resistance. Whole-exome sequencing and functional validation identified an acquired PIK3CAE545K mutation as conferring drug resistance. We demonstrate that PIK3CAE545K preexisted in a rare subpopulation that was missed by both clinical and research testing, but was revealed upon multiregion sampling due to PIK3CAE545K being nonuniformly distributed. This resistant population rapidly expanded after the initiation of MEKi + CDK4i therapy and persisted in all successive samples even after immune checkpoint therapy and distant metastasis. Functional studies identified activated S6K1 as both a key marker and specific therapeutic vulnerability downstream of PIK3CAE545K-induced resistance. These results demonstrate that difficult-to-detect preexisting resistance mutations may exist more often than previously appreciated and also posit S6K1 as a common downstream therapeutic nexus for the MAPK, CDK4/6, and PI3K pathways.Significance: We report the first characterization of clinical acquired resistance to MEKi + CDK4i, identifying a rare preexisting PIK3CAE545K subpopulation that expands upon therapy and exhibits drug resistance. We suggest that single-region pretreatment biopsy is insufficient to detect rare, spatially segregated drug-resistant subclones. Inhibition of S6K1 is able to resensitize PIK3CAE545K-expressing NRAS-mutant melanoma cells to MEKi + CDK4i. Cancer Discov; 8(5); 556-67. ©2018 AACR.See related commentary by Sullivan, p. 532See related article by Teh et al., p. 568This article is highlighted in the In This Issue feature, p. 517.

Modeling Genomic Instability and Selection Pressure in a Mouse Model of Melanoma.

Tumor evolution is an iterative process of selection for pro-oncogenic aberrations. This process can be accelerated by genomic instability, but how it interacts with different selection bottlenecks to shape the evolving genomic landscape remains understudied. Here, we assessed tumor initiation and therapy resistance bottlenecks in mouse models of melanoma, with or without genomic instability. At the initiation bottleneck, whole-exome sequencing revealed that drug-naive tumors were genomically silent, and this was surprisingly unaffected when genomic instability was introduced via telomerase inactivation. We hypothesize that the strong engineered alleles created low selection pressure. At the therapy resistance bottleneck, strong selective pressure was applied using a BRAF inhibitor. In the absence of genomic instability, tumors acquired a non-genomic drug resistance mechanism. By contrast, telomerase-deficient, drug-resistant melanomas acquired highly recurrent copy number gains. These proof-of-principle experiments demonstrate how different selection pressures can interact with genomic instability to impact tumor evolution.

Sustained activation of SMAD3/SMAD4 by FOXM1 promotes TGF-ß-dependent cancer metastasis.

A key feature of TGF-ß signaling activation in cancer cells is the sustained activation of SMAD complexes in the nucleus; however, the drivers of SMAD activation are poorly defined. Here, using human and mouse breast cancer cell lines, we found that oncogene forkhead box M1 (FOXM1) interacts with SMAD3 to sustain activation of the SMAD3/SMAD4 complex in the nucleus. FOXM1 prevented the E3 ubiquitin-protein ligase transcriptional intermediary factor 1 γ (TIF1γ) from binding SMAD3 and monoubiquitinating SMAD4, which stabilized the SMAD3/SMAD4 complex. Loss of FOXM1 abolished TGF-ß-induced SMAD3/SMAD4 formation. Moreover, the interaction of FOXM1 and SMAD3 promoted TGF-ß/SMAD3-mediated transcriptional activity and target gene expression. We found that FOXM1/SMAD3 interaction was required for TGF-ß-induced breast cancer invasion, which was the result of SMAD3/SMAD4-dependent upregulation of the transcription factor SLUG. Importantly, the function of FOXM1 in TGF-ß-induced invasion was not dependent on FOXM1's transcriptional activity. Knockdown of SMAD3 diminished FOXM1-induced metastasis. Furthermore, FOXM1 levels correlated with activated TGF-ß signaling and metastasis in human breast cancer specimens. Together, our data indicate that FOXM1 promotes breast cancer metastasis by increasing nuclear retention of SMAD3 and identify crosstalk between FOXM1 and TGF-ß/SMAD3 pathways. This study highlights the critical interaction of FOXM1 and SMAD3 for controlling TGF-ß signaling during metastasis.

PML regulates PER2 nuclear localization and circadian function.

Studies have suggested that the clock regulator PER2 is a tumour suppressor. A cancer network involving PER2 raises the possibility that some tumour suppressors are directly involved in the mammalian clock. Here, we show that the tumour suppressor promyelocytic leukaemia (PML) protein is a circadian clock regulator and can physically interact with PER2. In the suprachiasmatic nucleus (SCN), PML expression and PML-PER2 interaction are under clock control. Loss of PML disrupts and dampens the expression of clock regulators Per2, Per1, Cry1, Bmal1 and Npas2. In the presence of PML and PER2, BMAL1/CLOCK-mediated transcription is enhanced. In Pml(-/-) SCN and mouse embryo fibroblast cells, the cellular distribution of PER2 is primarily perinuclear/cytoplasmic. PML is acetylated at K487 and its deacetylation by SIRT1 promotes PML control of PER2 nuclear localization. The circadian period of Pml(-/-) mice displays reduced precision and stability consistent with PML having a role in the mammalian clock mechanism.

FoxM1 promotes ß-catenin nuclear localization and controls Wnt target-gene expression and glioma tumorigenesis.

Wnt/ß-catenin signaling is essential for stem cell regulation and tumorigenesis, but its molecular mechanisms are not fully understood. Here, we report that FoxM1 is a downstream component of Wnt signaling and is critical for ß-catenin transcriptional function in tumor cells. Wnt3a increases the level and nuclear translocation of FoxM1, which binds directly to ß-catenin and enhances ß-catenin nuclear localization and transcriptional activity. Genetic deletion of FoxM1 in immortalized neural stem cells abolishes ß-catenin nuclear localization. FoxM1 mutations that disrupt the FoxM1-ß-catenin interaction or FoxM1 nuclear import prevent ß-catenin nuclear accumulation in tumor cells. FoxM1-ß-catenin interaction controls Wnt target gene expression, is required for glioma formation, and represents a mechanism for canonical Wnt signaling during tumorigenesis.

FoxM1B regulates NEDD4-1 expression, leading to cellular transformation and full malignant phenotype in immortalized human astrocytes.

Our recent studies have shown that the FoxM1B transcription factor is overexpressed in human glioma tissues and that the level of its expression correlates directly with glioma grade. However, whether FoxM1B plays a role in the early development of glioma (i.e., in transformation) is unknown. In this study, we found that the FoxM1B molecule causes cellular transformation and tumor formation in normal human astrocytes (NHA) immortalized by p53 and pRB inhibition. Moreover, brain tumors that arose from intracranial injection of FoxM1B-expressing immortalized NHAs displayed glioblastoma multiforme (GBM) phenotypes, suggesting that FoxM1B overexpression in immortalized NHAs not only transforms the cells but also leads to GBM formation. Mechanistically, our results showed that overexpression of FoxM1B upregulated NEDD4-1, an E3 ligase that mediates the degradation and downregulation of phosphatase and tensin homologue (PTEN) in multiple cell lines. Decreased PTEN in turn resulted in the hyperactivation of Akt, which led to phosphorylation and cytoplasmic retention of FoxO3a. Blocking Akt activation with phosphoinositide 3-kinase/Akt inhibitors inhibited the FoxM1B-induced transformation of immortalized NHAs. Furthermore, overexpression of FoxM1B in immortalized NHAs increased the expression of survivin, cyclin D1, and cyclin E, which are important molecules for tumor growth. Collectively, these results indicate that overexpression of FoxM1B, in cooperation with p53 and pRB inhibition in NHA cells, promotes astrocyte transformation and GBM formation through multiple mechanisms.

FoxM1B transcriptionally regulates vascular endothelial growth factor expression and promotes the angiogenesis and growth of glioma cells.

We previously found that FoxM1B is overexpressed in human glioblastomas and that forced FoxM1B expression in anaplastic astrocytoma cells leads to the formation of highly angiogenic glioblastoma in nude mice. However, the molecular mechanisms by which FoxM1B enhances glioma angiogenesis are currently unknown. In this study, we found that vascular endothelial growth factor (VEGF) is a direct transcriptional target of FoxM1B. FoxM1B overexpression increased VEGF expression, whereas blockade of FoxM1 expression suppressed VEGF expression in glioma cells. Transfection of FoxM1 into glioma cells directly activated the VEGF promoter, and inhibition of FoxM1 expression by FoxM1 siRNA suppressed VEGF promoter activation. We identified two FoxM1-binding sites in the VEGF promoter that specifically bound to the FoxM1 protein. Mutation of these FoxM1-binding sites significantly attenuated VEGF promoter activity. Furthermore, FoxM1 overexpression increased and inhibition of FoxM1 expression suppressed the angiogenic ability of glioma cells. Finally, an immunohistochemical analysis of 59 human glioblastoma specimens also showed a significant correlation between FoxM1 overexpression and elevated VEGF expression. Our findings provide both clinical and mechanistic evidence that FoxM1 contributes to glioma progression by enhancing VEGF gene transcription and thus tumor angiogenesis.

Exploration of coordination polymer as sorbent for flow injection solid-phase extraction on-line coupled with high-performance liquid chromatography for determination of polycyclic aromatic hydrocarbons in environmental materials.

The copper(II) isonicotinate (Cu(4-C5H4N-COO)2(H2O)4) coordination polymer was prepared, characterized and explored as sorbent for flow injection solid-phase extraction on-line coupled with high-performance liquid chromatography (HPLC) for determination of trace polycyclic aromatic hydrocarbons (PAHs) in environmental matrices. Naphthalene, phenanthrene, anthracene, fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene and benzo(ghi)perylene with various shape, size and hydrophobicity were used as model analytes. The porosity of the coordination polymer allows these guest PAHs molecules to diffuse into the buck structure, and the shape and size of the pores lead to shape- and size-selectivity over the guests. The precolumn packed with the coordination polymer was shown to be promising for solid-phase extraction of PAHs in environmental samples with subsequent HPLC separation and UV detection. With extraction of 50 ml of sample solution, the enhancement factors for the PAHs studied ranged from 200 to 2337, depending on the shape, size and hydrophobic property of the PAHs. The detection limits (S/N = 3) of 2-14 ng l(-1) and the sample throughput of 3 samples h(-1) were obtained. The developed method was applied to the determination of trace PAHs in a certified reference material (coal fly ash) and local water samples.

FoxM1B is overexpressed in human glioblastomas and critically regulates the tumorigenicity of glioma cells.

The transcription factor Forkhead box M1 (FoxM1) is overexpressed in malignant glioma. However, the functional importance of this factor in human glioma is not known. In the present study, we found that FoxM1B was the predominant FoxM1 isoform expressed in human glioma but not in normal brain tissue. The level of FoxM1 protein expression in human glioma tissues was directly correlated with the glioma grade. The level of FoxM1 protein expression in human glioblastoma tissues was inversely correlated with patient survival. Enforced FoxM1B expression caused SW1783 and Hs683 glioma cells, which do not form tumor xenografts, to regain tumorigenicity in nude mouse model systems. Moreover, gliomas that arose from FoxM1B-transfected anaplastic astrocytoma SW1783 cells displayed glioblastoma multiforme phenotypes. Inhibition of FoxM1 expression in glioblastoma U-87MG cells suppressed their anchorage-independent growth in vitro and tumorigenicity in vivo. Furthermore, we found that FoxM1 regulates the expression of Skp2 protein, which is known to promote degradation of the cell cycle regulator p27(Kip1). These results showed that FoxM1 is overexpressed in human glioblastomas and contributes to glioma tumorigenicity. Therefore, FoxM1 might be a new potential target of therapy for human malignant gliomas.

Activation of stat3 in human melanoma promotes brain metastasis.

Brain metastasis is a major cause of morbidity and mortality in patients with melanoma. The molecular changes that lead to brain metastasis remain poorly understood. In this study, we developed a model to study human melanoma brain metastasis and found that Stat3 activity was increased in human brain metastatic melanoma cells when compared with that in cutaneous melanoma cells. The expression of activated Stat3 is also increased in human brain metastasis specimens when compared with that in the primary melanoma specimens. Increased Stat3 activation by transfection with a constitutively activated Stat3 enhanced brain metastasis, whereas blockade of Stat3 activation by transfection with a dominant-negative Stat3 suppressed brain metastasis of human melanoma cells in animal models. Furthermore, altered Stat3 activity profoundly affected melanoma angiogenesis in vivo and melanoma cell invasion in vitro and significantly affected the expression of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and matrix metalloproteinase-2 (MMP-2) in vivo and in vitro. Finally, Stat3 activity transcriptionally regulated the promoter activity of bFGF in addition to VEGF and MMP-2 in human melanoma cells. These results indicated that Stat3 activation plays an important role in dysregulated expression of bFGF, VEGF, and MMP-2 as well as angiogenesis and invasion of melanoma cells and contributes to brain metastasis of melanoma. Therefore, Stat3 activation might be a new potential target for therapy of human melanoma brain metastases.

Stat3 activation regulates the expression of matrix metalloproteinase-2 and tumor invasion and metastasis.

The expression of matrix metalloproteinase-2 (MMP-2) has been linked with tumor invasion, angiogenesis, and metastasis. However, the molecular basis for MMP-2 overexpression in tumor cells remains unclear. In this study, by using K-1735 melanoma system, we demonstrated that highly metastatic C4, M2, and X21 tumor cells express elevated MMP-2 mRNA and enzymatic activity, whereas poorly metastatic C10, C19, and C23 tumor cells express much lower levels. Moreover, a concomitant elevated Stat3 activity has been detected in these metastatic tumor cells that overexpress MMP-2. Transfection of constitutively activated Stat3 into poorly metastatic C23 tumor cells directly activated the MMP-2 promoter, whereas the expression of a dominant-negative Stat3 in highly metastatic C4 tumor cells inhibited the MMP-2 promoter. A high-affinity Stat3-binding element was identified in the MMP-2 promoter and Stat3 protein bound directly to the MMP-2 promoter. Blockade of activated Stat3 through expression of a dominant-negative Stat3 significantly suppressed MMP-2 expression in the metastatic tumor cells. Therefore, overexpression of MMP-2 in the metastatic melanoma cells can be attributed to elevated Stat3 activity, and Stat3 upregulates the transcription of MMP-2 through direct interaction with the MMP-2 promoter. Furthermore, blockade of activated Stat3 in highly metastatic C4 cells significantly suppressed the invasiveness of the tumor cells, inhibited tumor growth, and prevented metastasis in nude mice. Collectively, these studies suggest that Stat3 signaling directly regulates MMP-2 expression, tumor invasion, and metastasis, and that Stat3 activation might be a crucial event in the development of metastasis.