The mystery of phospho-Drp1 with four adaptors in cell cycle: when mitochondrial fission couples to cell fate decisions.

Recent study had deepened our knowledge of the mitochondrial dynamics to classify mitochondrial fission into two types. To further clarify the relationship between the two distinct fission machinery and the four major adaptors of Drp1, we propose a model of mechanism elucidating the multiple functions of phospho-Drp1 with its adaptors during cell cycle and providing in-depth insights into the molecular basis and evolutionary implications in depth. The model highlights not only the clustering characteristics of different phospho-Drp1 with respective subsets of mitochondrial pro-fission adaptors but also the correlation, crosstalk and shifting between different clustering of phosphorylated Drp1-adaptors during different key fission situations. Particularly, phospho-Drp1 (Ser616) couples with Mff/MiD51 to exert mitochondrial division and phospho-Drp1 (Ser637) couples with MiD49/Fis1 to execute mitophagy in M-phase. We then apply the model to address the relationship of mitochondrial dynamics to Parkinson's disease (PD) and carcinogenesis. Our proposed model is indeed compatible with current research results and pathological observations, providing promising directions for future treatment design.

Galectin-3 Mediates Tumor Progression in Astrocytoma by Regulating Glycogen Synthase Kinase-3ß Activity.

Numerous studies have considered galectin-3 or Glycogen synthase kinase 3 beta (GSK3B) as a potential prognosis marker for various cancers. However, the correlation between the protein expression of galectin-3/GSK3B and the clinical parameters of astrocytoma has not been reported. This study aims to validate the correlation between the clinical outcomes and protein expression of galectin-3/GSK3B in astrocytoma. Immunohistochemistry staining was performed to detect galectin-3/GSK3B protein expression in patients with astrocytoma. The Chi-square test, Kaplan-Meier evaluation, and Cox regression analysis were used to determine the correlation between clinical parameters and galectin-3/GSK3B expression. Cell proliferation, invasion, and migration were compared between a non-siRNA group and a galectin-3/GSK3B siRNA group. Protein expression in galectin-3 or GSK3B siRNA-treated cells was evaluated using western blotting. Galectin-3 and GSK3B protein expression were significantly positively correlated with the World Health Organization (WHO) astrocytoma grade and overall survival time. Multivariate analysis revealed that WHO grade, galectin-3 expression, and GSK3B expression were independent prognostic factors for astrocytoma. Galectin-3 or GSK3B downregulation induced apoptosis and decreased cell numbers, migration, and invasion. siRNA-mediated gene silencing of galectin-3 resulted in the downregulation of Ki-67, cyclin D1, VEGF, GSK3B, p-GSK3B Ser9 (p-GSK3B S9), and ß-catenin. In contrast, GSK3B knockdown only decreased Ki-67, VEGF, p-GSK3B S9, and ß-catenin protein expression but did not affect cyclin D1 and galectin-3 protein expression. The siRNA results indicated that GSK3B is downstream of the galectin-3 gene. These data support that galectin-3 mediated tumor progression by upregulating GSK3B and ß-catenin protein expression in glioblastoma. Therefore, galectin-3 and GSK3B are potential prognostic markers, and their genes may be considered to be anticancer targets for astrocytoma therapy.

GSKIP modulates cell aggregation through EMT/MET signaling rather than differentiation in SH-SY5Y human neuroblastoma cells.

GSK3ß interacting protein (GSKIP) is a small A-kinase anchor protein previously reported to mediate the N-cadherin/ß-catenin pool for differentiation in SH-SY5Y cells through overexpression of GSKIP to present the neuron outgrowth phenotype. To further investigate how GSKIP functions in neurons, CRISPR/Cas9 technology was utilized to knock out GSKIP (GSKIP-KO) in SH-SY5Y. Several GSKIP-KO clones resulted in an aggregation phenotype and reduced cell growth without retinoic acid (RA) treatment. However, neuron outgrowth was still observed in GSKIP-KO clones treated with RA. The GSKIP-KO clones exhibited an aggregation phenotype through suppression of GSK3ß/ß-catenin pathways and cell cycle progression rather than cell differentiation. Gene set enrichment analysis indicated that GSKIP-KO was related to epithelial mesenchymal transition/mesenchymal epithelial transition (EMT/MET) and Wnt/ß-catenin/cadherin signaling pathways, suppressing cell migration and tumorigenesis through the inhibition of Wnt/ß-catenin mediated EMT/MET. Conversely, reintroduction of GSKIP into GSKIP-KO clones restored cell migration and tumorigenesis. Notably, phosphor-ß-catenin (S675) and ß-catenin (S552) but not phosphor-ß-catenin (S33/S37/T41) translocated into the nucleus for further gene activation. Collectively, these results suggested that GSKIP may function as an oncogene to form an aggregation phenotype for cell survival in harsh environments through EMT/MET rather than differentiation in the GSKIP-KO of SH-SY5Y cells. GSKIP Implication in Signaling Pathways with Potential Impact on SHSY-5Y Cell Aggregation.

BMX, a specific HDAC8 inhibitor, with TMZ for advanced CRC therapy: a novel synergic effect to elicit p53-, ß-catenin- and MGMT-dependent apoptotic cell death.

BACKGROUND: Despite advances in treatment, patients with refractory colorectal cancer (CRC) still have poor long-term survival, so there is a need for more effective therapeutic options. METHODS: To evaluate the HDAC8 inhibition efficacy as a CRC treatment, we examined the effects of various HDAC8 inhibitors (HDAC8i), including BMX (NBM-T-L-BMX-OS01) in combination with temozolomide (TMZ) or other standard CRC drugs on p53 mutated HT29 cells, as well as wild-type p53 HCT116 and RKO cells. RESULTS: We showed that HDAC8i with TMZ cotreatment resulted in HT29 arrest in the S and G2/M phase, whereas HCT116 and RKO arrest in the G0/G1 phase was accompanied by high sub-G1. Subsequently, this combination approach upregulated p53-mediated MGMT inhibition, leading to apoptosis. Furthermore, we observed the cotreatment also enabled triggering of cell senescence and decreased expression of stem cell biomarkers. Mechanistically, we found down-expression levels of ß-catenin, cyclin D1 and c-Myc via GSK3ß/ß-catenin signaling. Intriguingly, autophagy also contributes to cell death under the opposite status of ß-catenin/p62 axis, suggesting that there exists a negative feedback regulation between Wnt/ß-catenin and autophagy. Consistently, the Gene Set Enrichment Analysis (GSEA) indicated both apoptotic and autophagy biomarkers in HT29 and RKO were upregulated after treating with BMX. CONCLUSIONS: BMX may act as a HDAC8 eraser and in combination with reframed-TMZ generates a remarkable synergic effect, providing a novel therapeutic target for various CRCs. Video Abstract.

Compound cellular stress maximizes apoptosis independently of p53 in glioblastoma.

We examined the apoptotic response of two glioblastoma cells, p53 wild type U87 and p53 mutated T98G, to doxorubicin, bortezomib, and vorinostat, which respectively target DNA, 26S proteasome and histone deacetylase, to clarify p53's function in apoptosis. We demonstrated that doxorubicin induced apoptosis in U87 cells but not in T98G cells. The level of p53 was definitively correlated to the extent of DNA damage and apoptosis initiation. Dominant-negative p53 reduced p21 expression, but did not affect doxorubicin-induced apoptosis, so the transcriptional activity of p53 seemed not to participate in doxorubicin-induced apoptosis. However, p53 concentrated into the nucleus during heavy apoptosis. Bortezomib could induce apoptosis in U87 with high sensitivity and T98G cells with low sensitivity. In contrast, vorinostat promoted apoptosis in both U87 and T98G cells and reduced the basal level of p53 in U87 cells, indicating that p53 played no role in the vorinostat-induced apoptosis. To clearly define the role of p53 in bortezomib- and doxorubicin-induced apoptosis, we combined doxorubicin with bortezomib to treat U87 cells to assess this combination's effect on apoptosis and p53 status. Interestingly, the combination of doxorubicin with bortezomib engendered compound stress, resulting in a synergistic outcome for apoptosis in U87 cells. However, the amounts of p53 in the total count and in the nucleus were much lower with the combination than with doxorubicin alone, suggesting that p53 played no role in either the compound stress, doxorubicin-only or bortezomib-induced apoptosis.

Deciphering the evolution of composite-type GSKIP in mitochondria and Wnt signaling pathways.

We previously revealed the origin of mammalian simple-type glycogen synthase kinase interaction protein (GSKIP), which served as a scavenger and a competitor in the Wnt signaling pathway during evolution. In this study, we investigated the conserved and nonconserved regions of the composite-type GSKIP by utilizing bioinformatics tools, site-directed mutagenesis, and yeast two-hybrid methods. The regions were denoted as the pre-GSK3ß binding site, which is located at the front of GSK3ß-binding sites. Our data demonstrated that clustered mitochondria protein 1 (CLU1), a type of composite-type GSKIP that exists in the mitochondria of all eukaryotic organisms, possesses the protein known as domain of unknown function 727 (DUF727), with a pre-GSK3ß-binding site and a mutant GSK3ß-binding flanking region. Another type of composite-type GSKIP, armadillo repeat containing 4 (ARMC4), which is known for cilium movement in vertebrates, contains an unintegrated DUF727 flanking region with a pre-GSK3ß-binding site (115SPxF118) only. In addition, the sequence of the GSK3ß-binding site in CLU1 revealed that Q126L and V130L were not conserved, differing from the ideal GSK3ß-binding sequence of simple-type GSKIP. We further illustrated two exceptions, namely 70 kilodalton heat shock proteins (Hsp70/DnaK) and Mitofilin in nematodes, that presented an unexpected ideal GSK3ß-binding region with a pre-GSK3ß sequence; this composite-type GSKIP could only occur in vertebrate species. Furthermore, we revealed the importance of the pre-GSK3ß-binding site (118F or 118Y) and various mutant GSK3ß-binding sites of composite-type GSKIP. Collectively, our data suggest that the new composite-type GSKIP starts with a DUF727 domain followed by a pre-GSK3ß-binding site, with the subsequent addition of the GSK3ß-binding site, which plays vital roles for CLU1, Mitofilin, and ARMC4 in mitochondria and Wnt signaling pathways during evolution.

Ionizing Radiation Induces Resistant Glioblastoma Stem-Like Cells by Promoting Autophagy via the Wnt/ß-Catenin Pathway.

Therapeutic resistance in recurrent glioblastoma multiforme (GBM) after concurrent chemoradiotherapy (CCRT) is a challenging issue. Although standard fractionated radiation is essential to treat GBM, it has led to local recurrence along with therapy-resistant cells in the ionizing radiation (IR) field. Lines of evidence showed cancer stem cells (CSCs) play a vital role in therapy resistance in many cancer types, including GBM. However, the molecular mechanism is poorly understood. Here, we proposed that autophagy could be involved in GSC induction for radioresistance. In a clinical setting, patients who received radiation/chemotherapy had higher LC3II expression and showed poor overall survival compared with those with low LC3 II. In a cell model, U87MG and GBM8401 expressed high level of stemness markers CD133, CD44, Nestin, and autophagy marker P62/LC3II after receiving standard fractionated IR. Furthermore, Wnt/ß-catenin proved to be a potential pathway and related to P62 by using proteasome inhibitor (MG132). Moreover, pharmacological inhibition of autophagy with BAF and CQ inhibit GSC cell growth by impairing autophagy flux as demonstrated by decrease Nestin, CD133, and SOX-2 levels. In conclusion, we demonstrated that fractionated IR could induce GSCs with the stemness phenotype by P62-mediated autophagy through the Wnt/ß-catenin for radioresistance. This study offers a new therapeutic strategy for targeting GBM in the future.

NBM-BMX, an HDAC8 Inhibitor, Overcomes Temozolomide Resistance in Glioblastoma Multiforme by Downregulating the ß-Catenin/c-Myc/SOX2 Pathway and Upregulating p53-Mediated MGMT Inhibition.

Although histone deacetylase 8 (HDAC8) plays a role in glioblastoma multiforme (GBM), whether its inhibition facilitates the treatment of temozolomide (TMZ)-resistant GBM (GBM-R) remains unclear. By assessing the gene expression profiles from short hairpin RNA of HDAC8 in the new version of Connectivity Map (CLUE) and cells treated by NBM-BMX (BMX)-, an HDAC8 inhibitor, data analysis reveals that the Wnt signaling pathway and apoptosis might be the underlying mechanisms in BMX-elicited treatment. This study evaluated the efficacy of cotreatment with BMX and TMZ in GBM-R cells. We observed that cotreatment with BMX and TMZ could overcome resistance in GBM-R cells and inhibit cell viability, markedly inhibit cell proliferation, and then induce cell cycle arrest and apoptosis. In addition, the expression level of ß-catenin was reversed by proteasome inhibitor via the ß-catenin/ GSK3ß signaling pathway to reduce the expression level of c-Myc and cyclin D1 in GBM-R cells. BMX and TMZ cotreatment also upregulated WT-p53 mediated MGMT inhibition, thereby triggering the activation of caspase-3 and eventually leading to apoptosis in GBM-R cells. Moreover, BMX and TMZ attenuated the expression of CD133, CD44, and SOX2 in GBM-R cells. In conclusion, BMX overcomes TMZ resistance by enhancing TMZ-mediated cytotoxic effect by downregulating the ß-catenin/c-Myc/SOX2 signaling pathway and upregulating WT-p53 mediated MGMT inhibition. These findings indicate a promising drug combination for precision personal treating of TMZ-resistant WT-p53 GBM cells.

The Phosphorylation Status of Drp1-Ser637 by PKA in Mitochondrial Fission Modulates Mitophagy via PINK1/Parkin to Exert Multipolar Spindles Assembly during Mitosis.

Mitochondrial fission and fusion cycles are integrated with cell cycle progression. Here we first re-visited how mitochondrial ETC inhibition disturbed mitosis progression, resulting in multipolar spindles formation in HeLa cells. Inhibitors of ETC complex I (rotenone, ROT) and complex III (antimycin A, AA) decreased the phosphorylation of Plk1 T210 and Aurora A T288 in the mitotic phase (M-phase), especially ROT, affecting the dynamic phosphorylation status of fission protein dynamin-related protein 1 (Drp1) and the Ser637/Ser616 ratio. We then tested whether specific Drp1 inhibitors, Mdivi-1 or Dynasore, affected the dynamic phosphorylation status of Drp1. Similar to the effects of ROT and AA, our results showed that Mdivi-1 but not Dynasore influenced the dynamic phosphorylation status of Ser637 and Ser616 in Drp1, which converged with mitotic kinases (Cdk1, Plk1, Aurora A) and centrosome-associated proteins to significantly accelerate mitotic defects. Moreover, our data also indicated that evoking mito-Drp1-Ser637 by protein kinase A (PKA) rather than Drp1-Ser616 by Cdk1/Cyclin B resulted in mitochondrial fission via the PINK1/Parkin pathway to promote more efficient mitophagy and simultaneously caused multipolar spindles. Collectively, this study is the first to uncover that mito-Drp1-Ser637 by PKA, but not Drp1-Ser616, drives mitophagy to exert multipolar spindles formation during M-phase.

MiR-1271 regulates glioblastoma cell proliferation and invasion by directly targeting the CAMKK2 gene.

This study explored the regulatory role of microRNA-1271 (miR-1271) in glioblastoma multiforme (GBM) proliferation and invasion via calcium/calmodulin-dependent protein kinase 2 (CaMKK2). MiR-1271 and CaMKK2 expression were quantified in normal human astrocyte cells, GBM cell lines, and low- and high-grade glioma tissues. MKI67 expression in GBM cells was measured using quantitative real-time polymerase chain reaction. The target relationship between miR-1271 and the CAMKK2 gene was confirmed using the luciferase reporter assay. MTT and Transwell assays were used to analyze the role of miR-1271 and CAMKK2 in cell proliferation and invasion. Finally, CaMKK2 expression and AKT phosphorylation were detected by western blotting. MiR-1271 was significantly downregulated in high-grade glioma tissues and GBM cell lines. Conversely, CAMKK2 mRNA expression was upregulated in high-grade glioma tissues and GBM cell lines. We observed that miR-1271 directly targeted the 3'-untranslated region of CAMKK2, indicating an inverse relationship with miR-1271. Overexpressing miR-1271 inhibited GBM cell proliferation and invasion, whereas inhibiting miR-1271 increased cell proliferation and invasion. Silencing CAMKK2 expression also inhibited GBM cell proliferation and invasion. Furthermore, overexpressing miR-1271 inhibited AKT phosphorylation and MKI67 mRNA expression by targeting CAMKK2. These results indicate that miR-1271 regulates GBM cell proliferation and invasion, and that these effects involve directly targeting the CAMKK2 gene. Therefore, miR-1271 may serve as a new therapeutic target for developing GBM treatments.

GSKIP-Mediated Anchoring Increases Phosphorylation of Tau by PKA but Not by GSK3beta via cAMP/PKA/GSKIP/GSK3/Tau Axis Signaling in Cerebrospinal Fluid and iPS Cells in Alzheimer Disease.

Based on the protein kinase A (PKA)/GSK3ß interaction protein (GSKIP)/glycogen synthase kinase 3ß (GSK3ß) axis, we hypothesized that these might play a role in Tau phosphorylation. Here, we report that the phosphorylation of Tau Ser409 in SHSY5Y cells was increased by overexpression of GSKIP WT more than by PKA- and GSK3ß-binding defective mutants (V41/L45 and L130, respectively). We conducted in vitro assays of various kinase combinations to show that a combination of GSK3ß with PKA but not Ca2+/calmodulin-dependent protein kinase II (CaMK II) might provide a conformational shelter to harbor Tau Ser409. Cerebrospinal fluid (CSF) was evaluated to extend the clinical significance of Tau phosphorylation status in Alzheimer's disease (AD), neurological disorders (NAD), and mild cognitive impairment (MCI). We found higher levels of different PKA-Tau phosphorylation sites (Ser214, Ser262, and Ser409) in AD than in NAD, MCI, and normal groups. Moreover, we used the CRISPR/Cas9 system to produce amyloid precursor protein (APPWT/D678H) isogenic mutants. These results demonstrated an enhanced level of phosphorylation by PKA but not by the control. This study is the first to demonstrate a transient increase in phosphor-Tau caused by PKA, but not GSK3ß, in the CSF and induced pluripotent stem cells (iPSCs) of AD, implying that both GSKIP and GSK3ß function as anchoring proteins to strengthen the cAMP/PKA/Tau axis signaling during AD pathogenesis.

Meningeal Melanocytoma Associated with Nevus of Ota: Analysis of Twelve Reported Cases.

BACKGROUND: Primary melanocytic neoplasms (PMNs) are rare neoplasms, especially within the central nervous system. Meningeal melanocytomas, a subtype of PMN, are even rarer. Nevus of Ota results from the incomplete migration of melanocytes from the neural crest. Synchronous nevus of Ota and meningeal melanocytoma are infrequently encountered in clinical practice. OBJECTIVE: To evaluate and elucidate 12 cases of synchronous meningeal melanocytoma and nevus of Ota, thereby improving the understanding of the relationship between these 2 diseases. METHODS: We reviewed cases and searched the English-language literature from the PubMed database and collected clinical parameters of 12 cases of synchronously occurring nevus of Ota and meningeal melanocytoma. RESULTS: Among the 12 cases, 90.90% and 91.66% of the lesions were located ipsilaterally and supratentorially, respectively. CONCLUSIONS: Our findings indicated a trend for both types of lesion to be located ipsilaterally and supratentorially. When a patient with nevus of Ota is found to harbor an intracranial neoplasm, the most likely diagnosis is PMN.

Thioridazine Enhances P62-Mediated Autophagy and Apoptosis Through Wnt/ß-Catenin Signaling Pathway in Glioma Cells.

Thioridazine (THD) is a common phenothiazine antipsychotic drug reported to suppress growth in several types of cancer cells. We previously showed that THD acts as an antiglioblastoma and anticancer stem-like cell agent. However, the signaling pathway underlying autophagy and apoptosis induction remains unclear. THD treatment significantly induced autophagy with upregulated AMPK activity and engendered cell death with increased sub-G1 in glioblastoma multiform (GBM) cell lines. Notably, through whole gene expression screening with THD treatment, frizzled (Fzd) proteins, a family of G-protein-coupled receptors, were found, suggesting the participation of Wnt/ß-catenin signaling. After THD treatment, Fzd-1 and GSK3ß-S9 phosphorylation (inactivated form) was reduced to promote ß-catenin degradation, which attenuated P62 inhibition. The autophagy marker LC3-II markedly increased when P62 was released from ß-catenin inhibition. Additionally, the P62-dependent caspase-8 activation that induced P53-independent apoptosis was confirmed by inhibiting T-cell factor/ß-catenin and autophagy flux. Moreover, treatment with THD combined with temozolomide (TMZ) engendered increased LC3-II expression and caspase-3 activity, indicating promising drug synergism. In conclusion, THD induces autophagy in GBM cells by not only upregulating AMPK activity, but also enhancing P62-mediated autophagy and apoptosis through Wnt/ß-catenin signaling. Therefore, THD is a potential alternative therapeutic agent for drug repositioning in GBM.

GSK3ß­mediated Ser156 phosphorylation modulates a BH3­like domain in BCL2L12 during TMZ­induced apoptosis and autophagy in glioma cells.

BH3 domains, classified initially as BCL2 homology domains, participate in both apoptosis and autophagy. Beclin­1 contains a BH3 domain, which is required for binding to antiapoptotic BCL2 homologs and BCL2­mediated inhibition of autophagy. BCL2­like 12 (BCL2L12) also harbors a BH3­like domain, which is 12 residues long and contains a LXXXAE/D motif. In a yeast two­hybrid system performed in the present study, BCL2L12 shared similar binding partnerships to antiapoptotic BCL2 homologs, such as Beclin­1. In addition, this BH3­like domain was involved in anti­apoptosis and drug­induced autophagy in glioma cell lines. Mutations in S156 and hydrophobic L213 to alanine counteracted the antiapoptotic properties of BCL2L12 and downregulated the activation of microtubule associated protein 1 light chain 3B (LC3B), autophagy­related (ATG)12­ATG5 conjugates and Beclin­1, compared with a BCL2L12 wild­type group. Molecular dynamics simulations revealed that phosphorylation at Ser156 of BCL2L12 (within α­6 and α­7 helices) influenced the BH3­like domain conformation (α­9 helix), indicating that glycogen synthase kinase (GSK) 3ß­mediated Ser156 phosphorylation modulated a BH3­like domain in BCL2L12. Altogether, the present findings indicated that BCL2L12 may participate in anti­apoptosis and autophagy via a BH3­like domain and GSK3ß­mediated phosphorylation at Ser156. Furthermore, blockade of temozolomide (TMZ)­induced autophagy by 3­methyladenine (3­MA) resulted in enhanced activation of apoptotic markers, as well as tumor suppresor protein p53 (p53) expression in U87MG cells. The present results suggested that p53 and O6­methylguanine DNA methyltransferase activation, and BCL2, BCL­extra large, Beclin­1 and BCL2L12 expression may be used as a detection panel to determine which patients can benefit from TMZ and ABT­737 combination treatment.

The origin of GSKIP, a multifaceted regulatory factor in the mammalian Wnt pathway.

GSK3ß interacting protein (GSKIP) is a naturally occurring negative regulator of GSK3ß and retains both the Protein Kinase A Regulatory subunit binding (PKA-RII) domain and GSK3ß interacting domain. Of these two domains, we found that PKA-RII is required for forming a working complex comprising PKA/GSKIP/GSK3ß/Drp1 to influence phosphorylation of Drp1 Ser637. In this study, bioinformatics and experimental explorations re-analyzing GSKIP's biofunctions suggest that the evolutionarily conserved Domain of Unknown Function (DUF727) is an ancestral prototype of GSKIP in prokaryotes, and acquired the C-terminal GSK3ß binding site (tail) in invertebrates except for Saccharomyces spp., after which the N-terminal PKA-RII binding region (head) evolved in vertebrates. These two regions mutually influence each other and modulate GSKIP binding to GSK3ß in yeast two-hybrid assays and co-immunoprecipitation. Molecular modeling showed that mammalian GSKIP could form a dimer through the L130 residue (GSK3ß binding site) rather than V41/L45 residues. In contrast, V41/L45P mutant facilitated a gain-of-function effect on GSKIP dimerization, further influencing binding behavior to GSK3ß compared to GSKIP wild-type (wt). The V41/L45 residues are not only responsible for PKA RII binding that controls GSK3ß activity, but also affect dimerization of GSKIP monomer, with net results of gain-of-function in GSKIP-GSK3ß interaction. In addition to its reported role in modulating Drp1, Ser637 phosphorylation caused mitochondrial elongation; we postulated that GSKIP might be involved in the Wnt signaling pathway as a scavenger to recruit GSK3ß away from the ß-catenin destruction complex and as a competitor to compete for GSK3ß binding, resulting in accumulation of S675 phosphorylated ß-catenin.

A Case of Leptomeningeal Dissemination of Pilocytic Astrocytoma in a Child.

We present the case of a 2-year-old boy with progressive left-sided weakness and a cranial magnetic resonance imaging (MRI) scan showing a lesion with a cystic component in the right thalamus and basal ganglia. The lesion was subtotally resected and diagnosed as a pilocytic astrocytoma by histopathology. Tumor seeding along the surgical tract was seen on MRI 16 days and 10 weeks after surgery. The patient received vincristine and carboplatin, and MRI performed 4 months after chemotherapy revealed no additional or residual lesions. This case illustrated that a World Health Organization grade I astrocytoma could disseminate along the surgical tract.

Predictive model for 5-year mortality after breast cancer surgery in Taiwan residents.

BACKGROUND: Few studies of breast cancer surgery outcomes have used longitudinal data for more than 2 years. This study aimed to validate the use of the artificial neural network (ANN) model to predict the 5-year mortality of breast cancer patients after surgery and compare predictive accuracy between the ANN model, multiple logistic regression (MLR) model, and Cox regression model. METHODS: This study compared the MLR, Cox, and ANN models based on clinical data of 3632 breast cancer patients who underwent surgery between 1996 and 2010. An estimation dataset was used to train the model, and a validation dataset was used to evaluate model performance. The sensitivity analysis was also used to assess the relative significance of input variables in the prediction model. RESULTS: The ANN model significantly outperformed the MLR and Cox models in predicting 5-year mortality, with higher overall performance indices. The results indicated that the 5-year postoperative mortality of breast cancer patients was significantly associated with age, Charlson comorbidity index (CCI), chemotherapy, radiotherapy, hormone therapy, and breast cancer surgery volumes of hospital and surgeon (all P < 0.05). Breast cancer surgery volume of surgeon was the most influential (sensitive) variable affecting 5-year mortality, followed by breast cancer surgery volume of hospital, age, and CCI. CONCLUSIONS: Compared with the conventional MLR and Cox models, the ANN model was more accurate in predicting 5-year mortality of breast cancer patients who underwent surgery. The mortality predictors identified in this study can also be used to educate candidates for breast cancer surgery with respect to the course of recovery and health outcomes.

AIBp regulates mitotic entry and mitotic spindle assembly by controlling activation of both Aurora-A and Plk1.

We previously reported that Aurora-A and the hNinein binding protein AIBp facilitate centrosomal structure maintenance and contribute to spindle formation. Here, we report that AIBp also interacts with Plk1, raising the possibility of functional similarity to Bora, which subsequently promotes Aurora-A-mediated Plk1 activation at Thr210 as well as Aurora-A activation at Thr288. In kinase assays, AIBp acts not only as a substrate but also as a positive regulator of both Aurora-A and Plk1. However, AIBp functions as a negative regulator to block phosphorylation of hNinein mediated by Aurora-A and Plk1. These findings suggest a novel AIBp-dependent regulatory machinery that controls mitotic entry. Additionally, knockdown of hNinein caused failure of AIBp to target the centrosome, whereas depletion of AIBp did not affect the localization of hNinein and microtubule nucleation. Notably, knockdown of AIBp in HeLa cells impaired both Aurora-A and Plk1 kinase, resulting in phenotypes with multiple spindle pole formation and chromosome misalignment. Our data show that depletion of AIBp results in the mis-localization of TACC3 and ch-TOG, but not CEP192 and CEP215, suggesting that loss of AIBp dominantly affects the Aurora-A substrate to cause mitotic aberrations. Collectively, our data demonstrate that AIBp contributes to mitotic entry and bipolar spindle assembly and may partially control localization, phosphorylation, and activation of both Aurora-A and Plk1 via hNinein during mitotic progression.

GSKIP- and GSK3-mediated anchoring strengthens cAMP/PKA/Drp1 axis signaling in the regulation of mitochondrial elongation.

GSK3ß binding of GSKIP affects neurite outgrowth, but the physiological significance of PKA binding to GSKIP remains to be determined. We hypothesized that GSKIP and GSK3ß mediate cAMP/PKA/Drp1 axis signaling and modulate mitochondrial morphology by forming a working complex comprising PKA/GSKIP/GSK3ß/Drp1. We demonstrated that GSKIP wild-type overexpression increased phosphorylation of Drp1 S637 by 7-8-fold compared to PKA kinase-inactive mutants (V41/L45) and a GSK3ß binding-defective mutant (L130) under H2O2 and forskolin challenge in HEK293 cells, indicating that not only V41/L45, but also L130 may be involved in Drp1-associated protection of GSKIP. Interestingly, silencing either GSKIP or GSK3ß but not GSK3α resulted in a dramatic decrease in Drp1 S637 phosphorylation, revealing that both GSKIP and GSK3ß are required in this novel PKA/GSKIP/GSK3ß/Drp1 complex. Moreover, overexpressed kinase-dead GSK3ß-K85R, which retains the capacity to bind GSKIP, but not K85M which shows total loss of GSKIP-binding, has a higher Drp1 S637 phosphorylation similar to the GSKIP wt overexpression group, indicating that GSK3ß recruits Drp1 by anchoring rather than in a kinase role. With further overexpression of either V41/L45P or the L130P GSKIP mutant, the elongated mitochondrial phenotype was lost; however, ectopically expressed Drp1 S637D, a phosphomimetic mutant, but not S637A, a non-phosphorylated mutant, restored the elongated mitochondrial morphology, indicating that Drp1 is a downstream effector of direct PKA signaling and possibly has an indirect GSKIP function involved in the cAMP/PKA/Drp1 signaling axis. Collectively, our data revealed that both GSKIP and GSK3ß function as anchoring proteins in the cAMP/PKA/Drp1 signaling axis modulating Drp1 phosphorylation.

Bcl2L12 with a BH3-like domain in regulating apoptosis and TMZ-induced autophagy: a prospective combination of ABT-737 and TMZ for treating glioma.

Bcl2L12 as a new member of the Bcl2 family, which contains a BH2 domain and shares a lower amino acid similarity with other Bcl2 family proteins. Bcl2L12 is reported to be involved in apoptosis regulation, but this role remains controversial in different cancer type. Temozolomide (TMZ) is currently used to intervene glioma multiforme (GBM), but an acquired chemotherapeutic resistance maybe occurred due to undesired autophagy. Previous studies uncovered that Bcl2L12 may interact with Bcl-xL and may harbor a BH3-like domain. Therefore, we investigated whether this BH3-like domain is responsible for the Bcl2L12 anti-apoptotic property. Moreover, we tested whether ABT-737, a BH3 mimetic agent, can be combined with TMZ to treat GBM. We aligned Bcl2L12 with Bcl2 family members, compared interacting pattern of BH3 domain and their protein 3D structure. We identified that Bcl2L12 interacts with Bcl-xL and Bcl2 in yeast two-hybrid system. Bcl2L12192-220 was a minimal region for Bcl2L12-Bcl-xL interaction. Five-point mutations with respect to hydrophobic and charge residues were generated to test whether they are the key residue of BH3-like domain. Our data showed that both h1 (L213) and h2 residue (L217) are essential for Bcl2L12 interacting with Bcl2 family proteins. Ectopically expressed h1 or h2 mutant in U87MG cell line resulted in reactivation of cleaved-PARP, caspase-3 and cytochrome c releasing compared to Bcl2L12 wt group. Implementing ABT-737 combined with TMZ provided a superior effect on apoptosis induction in Bcl2L12 wt group, which effectively reactivated apoptotic markers. Altogether, our findings indicated that Bcl2L12 retains a BH3-like domain, which is important for the Bcl2L12 anti-apoptotic property and TMZ-induced autophagy. Our results basically support the idea of using ABT-737 to counteract the anti-apoptotic role of Bcl2L12 and sensitize drug response of the GBM cells to TMZ.