Genome-Wide Association Study in Asians Identifies Novel Loci for High Myopia and Highlights a Nervous System Role in Its Pathogenesis.

PURPOSE: To identify novel susceptibility loci for high myopia. DESIGN: Genome-wide association study (GWAS) followed by replication and meta-analysis. PARTICIPANTS: A total of 14 096 samples from East and Southeast Asian populations (2549 patients with high myopia and 11 547 healthy controls). METHODS: We performed a GWAS in 3269 Japanese individuals (1668 with high myopia and 1601 control participants), followed by replication analysis in a total of 10 827 additional samples (881 with high myopia and 9946 control participants) from Japan, Singapore, and Taiwan. To confirm the biological role of the identified loci in the pathogenesis of high myopia, we performed functional annotation and Gene Ontology (GO) analyses. MAIN OUTCOME MEASURES: We evaluated the association of single nucleotide polymorphisms with high myopia and GO terms enriched among genes identified in the current study. RESULTS: We identified 9 loci with genome-wide significance (P < 5.0 × 10-8). Three loci were previously reported myopia-related loci (ZC3H11B on 1q41, GJD2 on 15q14, and RASGRF1 on 15q25.1), and the other 6 were novel (HIVEP3 on 1p34.2, NFASC/CNTN2 on 1q32.1, CNTN4/CNTN6 on 3p26.3, FRMD4B on 3p14.1, LINC02418 on 12q24.33, and AKAP13 on 15q25.3). The GO analysis revealed a significant role of the nervous system related to synaptic signaling, neuronal development, and Ras/Rho signaling in the pathogenesis of high myopia. CONCLUSIONS: The current study identified 6 novel loci associated with high myopia and demonstrated an important role of the nervous system in the disease pathogenesis. Our findings give new insight into the genetic factors underlying myopia, including high myopia, by connecting previous findings and allowing for a clarified interpretation of the cause and pathophysiologic features of myopia at the molecular level.

Discovery and structural characterization of peficitinib (ASP015K) as a novel and potent JAK inhibitor.

Janus kinases (JAKs) are considered promising targets for the treatment of autoimmune diseases including rheumatoid arthritis (RA) due to their important role in multiple cytokine receptor signaling pathways. Recently, several JAK inhibitors have been developed for the treatment of RA. Here, we describe the identification of the novel orally bioavailable JAK inhibitor 18, peficitinib (also known as ASP015K), which showed moderate selectivity for JAK3 over JAK1, JAK2, and TYK2 in enzyme assays. Chemical modification at the C4-position of lead compound 5 led to a large increase in JAK inhibitory activity and metabolic stability in liver microsomes. Furthermore, we determined the crystal structures of JAK1, JAK2, JAK3, and TYK2 in a complex with peficitinib, and revealed that the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide scaffold of peficitinib forms triple hydrogen bonds with the hinge region. Interestingly, the binding modes of peficitinib in the ATP-binding pockets differed among JAK1, JAK2, JAK3, and TYK2. WaterMap analysis of the crystal structures suggests that unfavorable water molecules are the likely reason for the difference in orientation of the 1H-pyrrolo[2,3-b]pyridine-5-carboxamide scaffold to the hinge region among JAKs.

Semaphorin 3A controls allergic and inflammatory responses in experimental allergic conjunctivitis.

AIM: To assess the efficacy of topical Semaphorin-3A (SEMA3A) in the treatment of allergic conjunctivitis. METHODS: Experimental allergic conjunctivitis (EAC) mice model induced by short ragweed pollen (SRW) in 4-week-old of BALB/c mice, mice were evaluated using haematoxylin and eosin (H&E) staining, immunofluorescence and light microscope photographs. Early phase took the samples in 24h after instillation and late phase took the samples between 4 to 14d after the start of treatment. The study use of topical SEMA3A (10 U, 100 U, 1000 U) eye drops and subconjunctival injection of SEMA3A with same concentration. For comparison, five types of allergy eyedrops were quantified using clinical characteristics. RESULTS: Clinical score of composite ocular symptoms of the mice treated with SEMA3A were significantly decreased both in the immediate phase and the late phase compared to those treated with commercial ophthalmic formulations and non-treatment mice. SEMA3A treatment attenuates infiltration of eosinophils entering into conjunctiva in EAC mice. The score of eosinophil infiltration in the conjunctiva of SEMA3A 1000 U-treated group were significantly lower than low-concentration of SEMA3A treated groups and non-treated group. SEMA3A treatment also suppressed T-cell proliferation in vitro and decreased serum total IgE levels in EAC mice. Moreover, Treatment of SEMA3A suppressed Th2-related cytokines (IL-5, IL-13 and IL-4) and pro-inflammatory cytokines (IFN-γ, IL-17 and TNF-α) release, but increased regulatory cytokine IL-10 concentration in the conjunctiva of EAC mice. CONCLUSIONS: SEMA3A as a biological agent, showed the beneficial activity in ocular allergic processes with the less damage to the intraocular tissue. It is expected that SEMA3A may be contributed in patients with a more severe spectrum of refractory ocular allergic diseases including allergic conjunctivitis in the near future.

Association study of fibroblast growth factor 10 (FGF10) polymorphisms with susceptibility to extreme myopia in a Japanese population.

PURPOSE: The fibroblast growth factor 10 (FGF10) gene polymorphism rs339501 was previously reported to be associated with high myopia in a Chinese population. In the present study, we investigated whether FGF10 polymorphisms are associated with extreme myopia in a Japanese population as well. METHODS: A total of 433 Japanese patients with extreme myopia (≤ -10.00 diopters) and 542 Japanese healthy controls (+1.50 to -1.50 diopters) were recruited. We genotyped seven tagging single-nucleotide polymorphisms (SNPs), including rs339501, in FGF10. We also performed an imputation analysis to evaluate the potential association of ungenotyped FGF10 SNPs, and 34 SNPs were imputed. RESULTS: It was found that rs339501 and rs12517396 exhibited the strongest association with extreme myopia (p=3.9 × 10⁻4, corrected p [Pc]=0.0030). A significant association was also observed for rs10462070 (p=6.5 × 10⁻4, Pc=0.0059). These three SNPs were in strong linkage disequilibrium (D' ≥0.99, r² ≥0.96). However, the frequency of the A allele of rs339501 was increased in cases compared to controls, which differs from the increased frequency of the G allele in cases in the previous Chinese population. CONCLUSIONS: Three FGF10 SNPs in complete linkage disequilibrium--rs339501, rs12517396, and rs10462070--were associated with extreme myopia in the Japanese population, and the risk allele of rs339501 differed from the previous Chinese population. Therefore, these three SNPs may not be an important risk factor for susceptibility to extreme myopia. Further studies are needed to elucidate the possible contribution of the FGF10 region in the development of extreme myopia.

Association study of IGF1 polymorphisms with susceptibility to high myopia in a Japanese population.

PURPOSE: Polymorphisms in the insulin-like growth factor 1 (IGF1) gene were previously associated with high or extreme myopia in Caucasian and Chinese populations. In the present study, we investigated whether IGF1 polymorphisms are associated with high myopia in a Japanese population. METHODS: A total of 446 Japanese patients with high myopia (≤-9.00 diopters) and 481 Japanese healthy controls (+1.50 diopters to -1.50 diopters) were recruited. We genotyped seven tagging single-nucleotide polymorphisms (SNPs) in IGF1 and assessed allelic and haplotypic diversity in cases and controls. RESULTS: There were no statistically significant differences in the allele frequencies of IGF1 SNPs and genotypes between cases and controls (P>0.05). However, the A allele of rs5742629 and the G allele of rs12423791 were associated with a moderately increased risk of high myopia (odds ratio [OR] =1.20 and OR =1.21, respectively) with borderline statistical significance (P=0.0502, corrected P (Pc) =0.21 and P=0.064, Pc=0.29, respectively). The haplotype consisting of the A allele of rs5742629 and the G allele of rs12423791 was marginally associated with the risk of high myopia (P=0.041; OR =1.21); this association was not significant after correction (Pc=0.19). CONCLUSION: We found that the IGF1 SNPs are not significantly associated with high myopia in our Japanese population. Our results are in contrast to a previous study in which extreme myopia cases had significantly higher frequencies of the G allele of rs5742629 and the C allele of rs12423791 than controls. Therefore, the IGF1 SNPs may not be important factors for susceptibility to high myopia in all populations. Further genetic studies are needed to elucidate the possible contributions of the IGF1 region to the development of high myopia.

Archaeal ribosomal stalk protein interacts with translation factors in a nucleotide-independent manner via its conserved C terminus.

Protein synthesis on the ribosome requires translational GTPase factors to bind to the ribosome in the GTP-bound form, take individual actions that are coupled with GTP hydrolysis, and dissociate, usually in the GDP-bound form. The multiple copies of the flexible ribosomal stalk protein play an important role in these processes. Using biochemical approaches and the stalk protein from a hyperthermophilic archaeon, Pyrococcus horikoshii, we here provide evidence that the conserved C terminus of the stalk protein aP1 binds directly to domain I of the elongation factor aEF-2, irrespective of whether aEF-2 is bound to GTP or GDP. Site-directed mutagenesis revealed that four hydrophobic amino acids at the C terminus of aP1, Leu-100, 103, 106, and Phe-107, are crucial for the direct binding. P1 was also found to bind to the initiation factor aIF5B, as well as aEF-1α, but not aIF2γ, via its C terminus. Moreover, analytical ultracentrifugation and gel mobility shift analyses showed that a heptameric complex of aP1 and aP0, aP0(aP1)(2)(aP1)(2)(aP1)(2), can bind multiple aEF-2 molecules simultaneously, which suggests that individual copies of the stalk protein are accessible to the factor. The functional significance of the C terminus of the stalk protein was also shown using the eukaryotic proteins P1/P2 and P0. It is likely that the conserved C terminus of the stalk proteins of archaea and eukaryotes can bind to translation factors both before and after GTP hydrolysis. This consistent binding ability of the stalk protein may contribute to maintaining high concentrations of translation factors around the ribosome, thus promoting translational efficiency.

The mining of pearl formation genes in pearl oyster Pinctada fucata by cDNA suppression subtractive hybridization.

Recent researches revealed the regional preference of biomineralization gene transcription in the pearl oyster Pinctada fucata: it transcribed mainly the genes responsible for nacre secretion in mantle pallial, whereas the ones regulating calcite shells expressed in mantle edge. This study took use of this character and constructed the forward and reverse suppression subtractive hybridization (SSH) cDNA libraries. A total of 669 cDNA clones were sequenced and 360 expressed sequence tags (ESTs) greater than 100 bp were generated. Functional annotation associated 95 ESTs with specific functions, and 79 among them were identified from P. fucata at the first time. In the forward SSH cDNA library, it recognized mass amount of nacre protein genes, biomineralization genes dominantly expressed in the mantle pallial, calcium-ion-binding genes, and other biomineralization-related genes important for pearl formation. Real-time PCR showed that all the examined genes were distributed in oyster mantle tissues with a consistence to the SSH design. The detection of their RNA transcripts in pearl sac confirmed that the identified genes were certainly involved in pearl formation. Therefore, the data from this work will initiate a new round of pearl formation gene study and shed new insights into molluscan biomineralization.

Genotyping HLA-DRB1 and HLA-DQB1 alleles in Japanese patients with normal tension glaucoma.

PURPOSE: Normal tension glaucoma (NTG) is a subtype of glaucoma in which intraocular pressure is within the statistically normal range. NTG may be associated with an immune disorder. The aim of this study was to determine whether specific alleles in the human leukocyte antigen (HLA)-DRB1 and HLA-DQB1 genes correlated with NTG in Japanese patients. METHODS: We genotyped the HLA-DRB1 and HLA-DQB1 alleles in 113 Japanese patients with NTG and in 184 healthy Japanese control subjects using the polymerase chain reaction-sequence-specific oligonucleotide probes (PCR-SSOP) Luminex method. We assessed the allelic diversity in patients and controls. RESULTS: There were no statistically significant differences in the allele frequency of HLADRB1 and HLA-DQB1 between NTG patients and control subjects, and no HLA-DRB1-HLA-DQB1 haplotypes demonstrated any significant association with NTG. CONCLUSIONS: Our findings suggest that HLA-DRB1 and HLA-DQB1 polymorphisms have no significant effect on the development of NTG in Japanese patients.

Analysis of microsatellite polymorphisms within the GLC1F locus in Japanese patients with normal tension glaucoma.

PURPOSE: To investigate whether the GLC1F locus is associated with normal tension glaucoma (NTG) in Japanese patients. METHODS: We recruited 242 unrelated Japanese subjects, including, 141 NTG patients and 101 healthy controls. The patients exhibiting a comparatively early onset were selected as they suggest that genetic factors may show stronger involvement. Genotyping and assessment of allelic diversity was performed on 11 highly polymorphic microsatellite markers in and around the GLC1F locus. RESULTS: Individuals carrying the 163 allele of D7S1277i had a statistically significant increased risk of NTG (p=0.0013, pc=0.016, OR=2.47, 95%CI=1.42-4.30). None of the other markers identified significant loci (pc>0.05) after Bonferroni's correction. CONCLUSIONS: These findings suggested that the genes in the GLC1F locus may be associated with the pathogenesis of NTG.

Structural basis for translation factor recruitment to the eukaryotic/archaeal ribosomes.

The archaeal ribosomal stalk complex has been shown to have an apparently conserved functional structure with eukaryotic pentameric stalk complex; it provides access to eukaryotic elongation factors at levels comparable to that of the eukaryotic stalk. The crystal structure of the archaeal heptameric (P0(P1)(2)(P1)(2)(P1)(2)) stalk complex shows that the rRNA anchor protein P0 consists of an N-terminal rRNA-anchoring domain followed by three separated spine helices on which three P1 dimers bind. Based on the structure, we have generated P0 mutants depleted of any binding site(s) for P1 dimer(s). Factor-dependent GTPase assay of such mutants suggested that the first P1 dimer has higher activity than the others. Furthermore, we constructed a model of the archaeal 50 S with stalk complex by superposing the rRNA-anchoring domain of P0 on the archaeal 50 S. This model indicates that the C termini of P1 dimers where translation factors bind are all localized to the region between the stalk base of the 50 S and P0 spine helices. Together with the mutational experiments we infer that the functional significance of multiple copies of P1 is in creating a factor pool within a limited space near the stalk base of the ribosome.

Association of microsatellite polymorphisms of the GPDS1 locus with normal tension glaucoma in the Japanese population.

BACKGROUND: To investigate whether the GPDS1 locus, a potential causative locus of pigment-dispersion syndrome, is associated with normal-tension glaucoma (NTG) in Japanese patients. MATERIALS AND METHODS: We used polymerase chain reaction amplification with sequence-specific primers to analyze 20 polymorphic microsatellite markers in and around the GPDS1 locus with an automated DNA analyzer and automated fragment detection by fluorescent-based technology. The DNA samples used for these analyses were obtained from ethnicity- and gender-matched patients, including 141 Japanese patients with NTG and 101 healthy controls. Patients exhibiting a comparatively early onset were selected as this suggests that genetic factors may show stronger involvement. RESULTS: One allele of D7S2462 exhibited a frequency that was significantly decreased in NTG cases compared to controls (P = 0.0013, Pc = 0.019, OR = 0.48, 95% CI = 0.30-0.75). Alleles at another six microsatellite loci were positively or negatively associated with NTG, but these associations did not retain statistical significance after Bonferroni correction (P < 0.05, Pc > 0.05). CONCLUSION: Our study showed a significant association between the GPDS1 locus and NTG, suggesting that there may be some genetic risk factor(s) in the development of NTG.

Rac1 mediates phorbol 12-myristate 13-acetate-induced migration of glioblastoma cells via paxillin.

Previously, we reported that phorbol 12-myristate 13-acetate (PMA)-activated protein kinase C (PKC) induced Rac1 activation in A172 glioblastoma cells. In this study, we investigated the mechanism of PMA-activated PKC-induced migration of glioblastoma cells by focusing on Rac1. PMA-induced formation of lamellipodia and focal complexes following migration were blocked by inhibiting Rac1 with small interfering RNA (siRNA), implicating Rac1 in PMA-induced glioblastoma cell migration. PMA-activated PKC induced phosphorylation of c-jun N-terminal kinase (JNK), one of the downstream effectors of Rac1. Immunohistochemical analysis showed that phosphorylated JNK was translocated to paxillin-containing focal complexes upon PMA stimulation and that Rac1 siRNA blocked these phenomena. These results suggest that phosphorylated JNK functions in cell migration and that JNK phosphorylation and translocation are mediated by Rac1. Furthermore, inhibition of Rac1 reduced phosphorylation of paxillin, a focal adhesion component and a downstream effector of JNK, at serine 178 (Ser178). Paxillin phosphorylation at this site has been shown to be involved in cell migration. Immunohistochemical analysis detected phosphorylation of paxillin (Ser178) in focal complexes upon PMA stimulation that was blocked by Rac1 siRNA. SP600125, a JNK inhibitor, also blocked PMA-induced phosphorylation of paxillin and aggregation of phosphorylated paxillin (Ser178) in focal complexes. In conclusion, paxillin is a critical downstream effector of Rac1 that may be involved in PMA-stimulated migration presumably by modulating the integrity of focal complex formation.

Src regulates phorbol 12-myristate 13-acetate-activated PKC-induced migration via Cas/Crk/Rac1 signaling pathway in glioblastoma cells.

In this study, we demonstrate that phorbol 12-myristate 13-acetate (PMA)-activated protein kinase C (PKC) induced migration in A172 glioblastoma cells via Src. PMA treatment induced tyrosine phosphorylation of Crk-associated substrate (Cas) and formation of a complex with Crk, followed by Rac1 activation, a downstream effector of Cas/Crk complex. These effects were blocked by a tyrosine kinase inhibitor (PP2) or Src small interfering RNA (siRNA), indicating that Src was involved in the PMA-induced activation of Cas/Crk/Rac1 signaling pathway. An immunohistochemical study showed that after PMA treatment, Cas, Crk and Rac1 translocated into lamellipodia. Tyrosine phosphorylated Cas was also detected at the periphery of the cells, where focal complexes were prominent. These results indicated that signaling of Cas, Crk and Rac1 might be involved in PMA-induced cytoskeletal reorganization. Translocation of Rac1 to the cell membrane is known to be dependent on phosphorylation of tyrosine-221 residue of Crk. We demonstrated that PMA induced phosphorylation of Crk, and this phosphorylation was blocked by PP2 or Src siRNA. These results indicated that Src might regulate the subcellular localization of Rac1 through phosphorylation of Crk. We propose that PMA-induced migration was dependent on activation of PKC/Src/Cas/Crk/Rac1 signaling pathway via modulating cytoskeletal reorganization during glioblastoma cell migration.

Phorbol 12-myristate 13-acetate (PMA)-induced migration of glioblastoma cells is mediated via p38MAPK/Hsp27 pathway.

We investigated the mechanism of phorbol 12-myristate 13-acetate (PMA)-induced migration of glioblastoma cells focusing on the p38 mitogen-activated protein kinase (MAPK)/heat shock protein 27 (Hsp27) pathway. PMA-induced cell migration and activation of p38MAPK in A172 glioblastoma cells. PMA-induced formation of lamellipodia and focal complexes was blocked by inhibiting p38MAPK with SB203580 or small interfering RNA (siRNA). Furthermore, activation of p38MAPK resulted in phosphorylation of an F-actin polymerization regulator, Hsp27. Immunohistochemical analysis showed that upon PMA stimulation, both unphosphorylated and phosphorylated Hsp27 were translocated to the lamellipodia. SB203580 or p38MAPK siRNA blocked these phenomena, indicating that Hsp27 phosphorylation and translocation from cytosol to membrane were mediated by p38MAPK. To address the question of whether endogenous Hsp27 participates in PMA-induced migration, we inhibited the expression of Hsp27 using Hsp27 siRNA. Although knockdown of Hsp27 by siRNA had little effect on p38MAPK activation, lamellipodia and focal complex formation was markedly inhibited. Migration was also abolished in Hsp27 siRNA-transfected cells. In conclusion, p38MAPK activation followed by Hsp27 phosphorylation was required for PMA-induced migration. Furthermore, Hsp27 itself played critical roles in PMA-induced migration. Our data provide substantial evidence for a model elucidating the molecular mechanisms of regulation of actin dynamics and migration by PMA-activated protein kinase C in glioblastoma cells.

Geldanamycin induces G2 arrest in U87MG glioblastoma cells through downregulation of Cdc2 and cyclin B1.

Cell cycle progression requires precise expression and activation of several cyclins and cyclin-dependent kinases. Geldanamycin (GA) affects cell cycle progression in various kinds of cells. We analyzed GA-induced cell cycle regulation in glioblastoma cells. GA-induced G2 or M arrest in glioblastoma cells in a cell line-dependent manner. GA decreased the expression of Cdc2 and cyclin B1 in U87MG cells. And phosphorylated Cdc2 decreased along with Cdc2 in the GA-treated cells. This cell line showed G2 arrest after GA treatment. In contrast, GA failed to down-regulate these cell cycle regulators in U251MG cells. In U251MG cells, the cell cycle was arrested at M phase in addition to G2 by GA. Next, we analyzed the mechanism of the GA-induced regulation of Cdc2 and cyclin B1 in U87MG cells. Cdc2 and cyclin B1 were ubiquitinated by GA. MG132 abrogated the GA-induced decrease of Cdc2 and cyclin B1 indicating that these proteins were degraded by proteasomes. In conclusion, GA controls the stability of Cdc2 and cyclin B1 in glioblastomas cell species-dependently. Cdc2 and cyclin B1 might be responsible for the different responses of glioblastoma cell lines to GA.

Phorbol 12-myristate 13-acetate-activated protein kinase C increased migratory activity of subconjunctival fibroblasts via stress-activated protein kinase pathways.

PURPOSE: The aim of this study was to clarify the mechanism of subconjunctival fibroblast migration, focusing on the effect of protein kinase C (PKC). METHODS: Subconjunctival fibroblasts were isolated from rats and cultured in 10% fetal bovine serum-containing culture medium. The fibroblasts were treated with phorbol 12-myristate 13-acetate (PMA) to activate PKC. Migration was assessed using a wound-healing assay. Western blot analysis was employed to examine activation of stress-activated protein kinase (SAPK) pathways. Immunofluorescent analysis was performed to examine the actin cytoskeleton dynamics. RESULTS: Seven PKC isoforms (alpha, beta, gamma, delta, epsilon, iota, and lambda) were present in rat subconjunctival fibroblasts. PMA induced lamellipodia formation and subsequent migration of the subconjunctival fibroblasts. PMA treatment in the subconjunctival fibroblasts elicited phosphorylation of SAPKs, including c-jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAPK). Treatment of the subconjunctival fibroblasts with an inhibitor of PKC abrogated the phosphorylation of these proteins. Furthermore, specific inhibitors of JNK and p38MAPK blocked PMA-induced migration of the subconjunctival fibroblasts. The phosphorylation of c-jun and heat shock protein 27, downstream effectors of JNK and p38MAPK, respectively, was upregulated by PMA treatment. CONCLUSIONS: PMA-activated PKC increased migratory activity, and SAPK pathways were critical for migration of subconjunctival fibroblasts.

Geldanamycin induces mitotic catastrophe and subsequent apoptosis in human glioma cells.

Geldanamycin (GA) binds to heat shock protein 90 (Hsp90) and interferes with its function which is to protect various cellular proteins involved in signaling, growth control, and survival from ubiquitination and subsequent degradation by the proteasome. Recently, we demonstrated that GA inhibited migration of glioma cells in vitro associated with downregulation of hypoxia-inducible factor (HIF-1 alpha) and phosphorylation of focal adhesion kinase (FAK) (Zagzag et al., 2003, J Cell Physiol 196:394-402). Here, we have investigated the mechanisms through which GA treatment of the T98G glioma cell line induces apoptosis. We found that GA treatment induced cell death in a caspase-dependent manner through activation of caspase-3 and PARP cleavage together with release of cytochrome c and apoptosis inducing factor (AIF) from the mitochondria. Use of synchronized T98G cells showed that GA treatment of glioma cells during S-phase enhanced cytotoxicity followed by M-phase arrest, resulting in mitotic catastrophe. In addition, apoptosis was associated with the downregulation of the survival protein, phosphorylated Akt (pAkt), an important signaling protein in the PI3K pathway, that is overexpressed in many cancers including gliomas. Given that many glioma tumors show deregulation of the PI3K signaling pathway, either through loss of the tumor suppressor protein PTEN or overexpression of the growth factor EGFR, the ability to identify different subsets of patients using simple immunohistochemistry for the presence of absence of pAkt could enable selection of the appropriate kinase inhibitor, such as GA, for drug therapy. Based on our data presented here, GA or its analogs may have potential in the treatment of glioma.

Geldanamycin inhibits migration of glioma cells in vitro: a potential role for hypoxia-inducible factor (HIF-1alpha) in glioma cell invasion.

Focal adhesion kinase (FAK) and hypoxia-inducible factor (HIF-1alpha) are both up-regulated in glioblastoma multiforme (GBMs), particularly in invasive zones. Because FAK may play an important role in the invasion of glioma cells into the surrounding brain, we sought an agent that causes down-regulation of FAK phosphorylation as a potential inhibitor of brain tumor invasion and growth. Geldanamycin (GA), a benzoquinone ansamycin antibiotic, binds to heat shock protein 90 (Hsp90) and interferes with its function. GA inhibits the proliferation of various non-glial cells and has anti-tumor activity. Moreover, GA blocks HIF-regulated transcription of VEGF and inhibits the VEGF-induced phosphorylation of FAK and migration of endothelial cells. Here, we tested the effect of GA on glioma cell migration in vitro and its potential to down-regulate HIF-1alpha induction. Our results demonstrate that GA (i) decreases U87MG, LN229, and U251MG glioma cell migration; (ii) reduces cell migration independent of p53 and PTEN status; (iii) prevents migration at non-toxic concentrations; (iv) reduces phosphorylation of FAK; and (v) inhibits cobalt chloride (CoCl(2))-mediated induction of HIF-1alpha in glioma cells. To the best of our knowledge, this is the first report showing that GA can inhibit phosphorylation of FAK concomitant with a decrease in cellular migration. One of the most clinically relevant aspects of this study is that GA interferes with the induction of HIF-1alpha that has been linked with glioma cell migration and angiogenesis. Given the fact that GA is a small lipophilic molecule capable of penetrating the blood brain barrier together with the data presented here provide a strong rationale for its use or its analogues in the treatment of highly invasive GBMs.