Abstract 5826: Essential role for cyclic-AMP responsive element binding protein 1 (CREB1) phosphorylation in the survival of medulloblastoma patients

Prognosis for recurrent medulloblastoma patients is extremely poor, with a median survival of 26.8 months. Treatment options for recurrent medulloblastoma patients are limited and ineffective due to resistance to chemotherapeutic agents and radiotherapy. Therefore, more research is required to address the high mortality of medulloblastoma patients that have therapy-resistant medulloblastoma. In a previous, study, we showed that cyclic-AMP responsive element binding protein (CREB1) was highly phosphorylated in primary medulloblastoma specimens. CREB is an important transcription factor involved in cerebellar cell proliferation and survival. In various cancers types, the expression of CREB is associated with prognosis. Untill now, CREB expression and its relation with overall survival has not been studied in medulloblastoma patients. In this study, we determined CREB phosphorylation levels and mRNA levels of CREB and its transcriptional co-activators CREBBP and EP300 using peptide phosphorylation and gene expression arrays in a cohort of 50 pediatric medulloblastoma patients. Furthermore, we performed shRNA-mediated knockdown of CREB, CREBBP and EP300 mRNA levels in medulloblastoma cell line DAOY. Knockdown was confirmed by means of qRT-PCR and western blotting. Next, cell viability assays were used to investigate the effect of chemotherapeutic reagents (etoposide and/or cisplatin) on cell viability in CREB, CREBBP or EP300 knockdown cells or in combination with a small molecule CREB inhibitor (KG-501).Low CREB phosphorylation levels in combination with low CREBBP and EP300 mRNA levels was significantly associated with poor overall survival (p=0.0001) with a median survival of 11.7 months in medulloblastoma patients. High CREB phosphorylation in combination with high CREBBP and EP300 mRNA levels was associated with a favourable prognosis (5 year-overall survival: 91%). Supervised clustering of gene expression data based upon low versus high CREB phosphorylation and CREBBP/EP300 mRNA levels and subsequent gene ontology analysis showed significant enrichment of genes associated with cerebellar and neuronal differentiation and development. Furthermore, knockdown with shCREB.3, shCBP.1-2 or shEP300A completely rescued DAOY cells from the etoposide-induced decrease in cell viability that was observed in the scrambled control. Similarly, addition of the CREB inhibitor KG-501 (2μM) completely rescued DAOY cells from the etoposide-induced decrease in cell viability and partially rescued DAOY cells from the cisplatin-induced decrease in cell viability.Together, these findings support an important role for CREB in neuronal differentiation, chemosensitivity and in the overall survival of pediatric medulloblastoma patients.

Citation Format: Walderik W. Zomerman, Sabine L. Plasschaert, Frank J. Scherpen, Harm Jan J. Lourens, Geesina C. Huizinga, Eelco W. Hoving, Wilfred F. den Dunnen, Sophia Bruggeman, Eveline S.J.M. de Bont. Essential role for cyclic-AMP responsive element binding protein 1 (CREB1) phosphorylation in the survival of medulloblastoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5826. doi:10.1158/1538-7445.AM2017-5826

Blood RNA biomarkers in prodromal PARK4 and rapid eye movement sleep behavior disorder show role of complexin 1 loss for risk of Parkinson's disease

Parkinson's disease (PD) is a frequent neurodegenerative process in old age. Accumulation and aggregation of the lipid-binding SNARE complex component α-synuclein (SNCA) underlies this vulnerability and defines stages of disease progression. Determinants of SNCA levels and mechanisms of SNCA neurotoxicity have been intensely investigated. In view of the physiological roles of SNCA in blood to modulate vesicle release, we studied blood samples from a new large pedigree with SNCA gene duplication (PARK4 mutation) to identify effects of SNCA gain of function as potential disease biomarkers. Downregulation of complexin 1 (CPLX1) mRNA was correlated with genotype, but the expression of other Parkinson's disease genes was not. In global RNA-seq profiling of blood from presymptomatic PARK4 indviduals, bioinformatics detected significant upregulations for platelet activation, hemostasis, lipoproteins, endocytosis, lysosome, cytokine, Toll-like receptor signaling and extracellular pathways. In PARK4 platelets, stimulus-triggered degranulation was impaired. Strong SPP1, GZMH and PLTP mRNA upregulations were validated in PARK4. When analysing individuals with rapid eye movement sleep behavior disorder, the most specific known prodromal stage of general PD, only blood CPLX1 levels were altered. Validation experiments confirmed an inverse mutual regulation of SNCA and CPLX1 mRNA levels. In the 3'-UTR of the CPLX1 gene we identified a single nucleotide polymorphism that is significantly associated with PD risk. In summary, our data define CPLX1 as a PD risk factor and provide functional insights into the role and regulation of blood SNCA levels. The new blood biomarkers of PARK4 in this Turkish family might become useful for PD prediction.

Informed Decision-Making Regarding Amputation for Complex Regional Pain Syndrome Type I

BACKGROUND

Literature on complex regional pain syndrome type I (CRPS-I) discussing the decision to amputate or not, the level of amputation, or the timing of the amputation is scarce. We evaluated informed decision-making regarding amputation for CRPS-I.

METHODS

We describe our findings in a retrospective study of the decision-making process of thirty-six patients who underwent amputation for CRPS-I at our university medical center from 2000 to 2012. Additionally, we present the incidents preceding the CRPS-I, the reasons for and the levels of the amputation, and the outcomes after the amputations.

RESULTS

Team members and the patient decided together whether or not to amputate and the level of amputation. Issues such as level of pain or allodynia, infection, desired length of the residual limb, joint range of motion, strength of all extremities, ability to use walking aids, and psychological "green, yellow, and red flags" were weighed in this process. There were no complications during the amputation surgery, a 22% rate of complications (infection in all but one patient) immediately postoperatively (reamputation not required), a 72% rate of phantom pain immediately after or within the first three months after the amputation, and a 77% rate of phantom pain more than one year after the amputation.

CONCLUSIONS

Informed decision-making regarding amputation for CRPS-I remains a complex process for which little evidence is available to support patient choices; patient-specific outcomes are not predictable. However, amputation should not be ignored as a treatment option for long-standing therapy-resistant CRPS-I.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Degeneration of the cerebellum in Huntington's disease (HD): possible relevance for the clinical picture and potential gateway to pathological mechanisms of the disease process

Huntington's disease (HD) is a polyglutamine disease and characterized neuropathologically by degeneration of the striatum and select layers of the neo- and allocortex. In the present study, we performed a systematic investigation of the cerebellum in eight clinically diagnosed and genetically confirmed HD patients. The cerebellum of all HD patients showed a considerable atrophy, as well as a consistent loss of Purkinje cells and nerve cells of the fastigial, globose, emboliform and dentate nuclei. This pathology was obvious already in HD brains assigned Vonsattel grade 2 striatal atrophy and did not correlate with the extent and distribution of striatal atrophy. Therefore, our findings suggest (i) that the cerebellum degenerates early during HD and independently from the striatal atrophy and (ii) that the onset of the pathological process of HD is multifocal. Degeneration of the cerebellum might contribute significantly to poorly understood symptoms occurring in HD such as impaired rapid alternating movements and fine motor skills, dysarthria, ataxia and postural instability, gait and stance imbalance, broad-based gait and stance, while the morphological alterations (ie ballooned neurons, torpedo-like axonal inclusions) observed in the majority of surviving nerve cells may represent a gateway to the unknown mechanisms of the pathological process of HD.

Amputation for long-standing, therapy-resistant type-I complex regional pain syndrome

BACKGROUND

Some patients with long-standing, therapy-resistant type-I complex regional pain syndrome consider an amputation. There is a lack of evidence regarding the risk of recurrence of the pain syndrome and patient outcomes after amputation. The goal of the present study was to evaluate the impact of an amputation on pain, participation in daily life activities, and quality of life as well as the use of a prosthesis and the risk of recurrence of the pain syndrome in patients with long-standing, therapy-resistant type-I complex regional pain syndrome.

METHODS

From May 2000 to October 2008, twenty-two patients underwent an amputation of a nonfunctional limb at our institution because of long-standing, therapy-resistant type-I complex regional pain syndrome. Twenty-one of these patients were included in our study. The median age was forty-six years (interquartile range [IQR], thirty-seven to fifty-one years), the median duration of the complex regional pain syndrome was six years (IQR, two to ten years), and the median interval between the amputation and the study was five years (IQR, three to seven years). A semistructured interview was conducted, physical examination of the residual limb was performed, and the patients completed two questionnaires.

RESULTS

Twenty patients (95%) reported an improvement in their lives. Nineteen patients (90%) reported a reduction in pain, seventeen patients (81%) reported an improvement in mobility, and fourteen (67%) reported an improvement in sleep. Eighteen of the twenty-one patients stated that they would choose to undergo an amputation again under the same circumstances. Ten of the fifteen patients with a lower-limb amputation and one of the six with an upper-limb amputation regularly used a prosthesis. The type-I complex regional pain syndrome recurred in the residual limb of three patients (14%) and symptoms recurred in another limb in two patients (10%).

CONCLUSIONS

Amputation may positively contribute to the lives of patients with long-standing, therapy-resistant type-I complex regional pain syndrome. Patients were likely to use a prosthesis after a lower-limb amputation. The risk of recurrence of the type-I complex regional pain syndrome was 24%.

Abstract 2377: Aminopeptidase A plays a role in VEGF-induced migration and proliferation through direct activation by VEGFR2 kinase activity

Tyrosine kinases pose attractive targets for cancer therapy, as their abnormal signaling activity results in enhanced proliferation, migration and angiogenesis. Previously we have been able to generate a comprehensive description of the biological kinase activity present in pediatric brain tumor tissue lysate by the application of a peptide microarray containing 144 different tyrosine kinase peptide substrates. To establish which peptide substrates present on the array are most sensitive and discriminative for VEGFR activity we measured the peptide phosphorylation applying recombinant VEGFR1, 2 and 3. Furthermore, a panel of recombinant kinases with highly diverse VEGFR sequence homology was included to study substrate specificity.

An aminopeptidase A (APA) derived peptide proved to be highly phosphorylated by VEGFR 1 and 2. No phosphorylation of this peptide could be observed applying any of the other kinases, arguing that this peptide is discriminative for VEGFR1 and 2 activity. In the peptide array data of pediatric brain tumors, phosphorylation of the APA peptide was observed, suggestive for VEGFR activation.

Based on these results we hypothesize that APA can be activated through direct phosphorylation by VEGFR2 and exert functional effects on endothelial cell proliferation and migration. To test this hypothesis we stimulated human umbilical vein endothelial cells (HUVECs) with VEGF and observed phosphorylation of Aminopeptidase A.

Literature states that inhibition of APA suppresses VEGF-induced migration and proliferation of endothelial cells and inhibits angiogenesis. Based on our data we hypothesize that these APA-mediated effects of VEGF stimulation are induced through direct activation by VEGFR2 kinase activity.

Concluding, peptide microarray technology is able to provide a selective view on tyrosine kinase activation, as has been shown here for VEGFR1 and 2.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2377.

Abstract 380: Sunitinib treatment induces up-regulation of CXCR4

Background: Chemokine receptors expressed on solid tumor cells and their corresponding ligands are an example of a network which is used by these cells to interact with their microenvironment to sustain survival, proliferation, invasive growth, angiogenesis, and to promote organ-specific localization of distant metastases. Indeed, CXCR4/CXCL12 signaling can induce angiogenesis and progression of tumors, for example by increasing the expression of vascular endothelial growth factor (VEGF). Inversely, it is hypothesized that anti-angiogenic treatment increases the expression of CXCR4/CXCL12 which could explain the in preclinical models observed invasive growth characteristics of tumors.

Methods: A human A2780 ovarian xenograft mouse model was used. When the tumor was established, mice were treated with vehicle or sunitinib (60 mg/kg i.p.) daily for 2 weeks. CXCR4 expression was assessed by immunohistochemistry at baseline and after 1 and 2 weeks of treatment and compared with markers like HIF1α, VEGF, Ki67, VEGFR2, mean vessel density (MVD) and blood vessel diameter. In addition human plasma VEGF levels were analyzed.

Results: Moderate cell membrane CXCR4 expression was seen in untreated tumors. One week of sunitinib treatment resulted in decrease angiogenice markers and tumor proliferation (Ki67) in both the tumor center and rim. Two weeks of sunitinib treatment resulted in up regulation of CXCR4 with a 2.2 fold increase (P = 0.046) particularly in the tumor rim. This coincided with normalization of blood vessel diameters, intense VEGF staining and increased tumor proliferation (Ki67) to baseline levels in the tumor rim. In contrast, an increase of HIF1α (P = 0.017) and decrease of angiogenic markers like VEGFR2 (P = 0.019) and MVD (P = 0.016) was still observed in the tumor center.

Conclusion: This study shows that anti-angiogenic treatment with sunitinib up regulates CXCR4 expression, mainly in the rim of the tumor. CXCR4 is a potential target to block anti-angiogenic induced invasive growth/metastasis.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 380.