Abstract B034: CXCR4 targeting endogenous human peptides eliminate migrating cancer stem cells by disrupting tumor-stroma crosstalk in pancreatic ductal adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer characterized by late diagnosis, lack of early symptoms and extensive metastasis. One of the foremost reasons for such startling statistics is the presence of a subpopulation of highly plastic stem-like cells within the tumor called cancer stem cells (CSCs). We have previously identified a distinct subset of these CSCs within the invasive front of patient tumors. This subset, called migrating cancer stem cells (miCSCs), is characterized by CD133+CXCR4+ expression and determines the metastatic phenotype of pancreatic cancer. Therefore, targeting CXCR4 may represent a potential therapeutic approach to lower metastatic burden in PDAC. Here, we examined the effect of endogenous human peptides EPI-X4 and other derivatives thereof as CXCR4 antagonist on (i) patient-derived primary pancreatic cancer cells and (ii) tumor-stroma crosstalk by using a dual culture system with pancreatic stellate cells. We established these peptides as novel therapeutic strategy for combating the metastatic activity of pancreatic cancer using combinatorial therapeutic approaches and testing different in vivo delivery system such as peptide fatty-acid (FA) conjugates and silica nanoparticles (Si-NP). Our results show that EPI-X4 as well as its derivatives (e.g., JM#21) strongly inhibited migratory capacity of primary pancreatic cancer cells towards the CXCR4 ligand CXCL12 in vitro. Thereby, JM#21 was identified as the most potent EPI-X4 derivate. Mechanistical analysis by western blot, gene expression and immunofluorescence revealed that JM#21 increased Cadherin-1 expression by suppression of Snail1 via inactivation of SHH pathway. Moreover, JM#21 decreased CXCL12-induced phosphorylation of AKT and IKBa as well as NANOG expression, which further suppressed self-renewal capacity and EMT in the tumor cells. Strikingly, JM#21 sensitized selected cell lines towards gemcitabine and paclitaxel. Furthermore, FA conjugated and Si-NP encapsulated JM#21 restricted miCSCs maintenance which was predominantly regulated via stellate cell secreted CXCL12. In serum conditions, both FA conjugated, and Si-NP encapsulated JM#21 was found to be stable and active, proving as a valuable delivery system for in vivo studies. In conclusion, our study reveals that targeting CXCR4/CXCL12 signaling axis using human endogenous EPI-X4 derivates particularly JM#21 inhibits tumor-stroma crosstalk which is paramount for the propagation and maintenance of miCSC. Particularly, we demonstrate, in both mechanistic and preclinical set up, that these peptides abrogate the metastatic capacity of patient-derived pancreatic cancer cells by selective targeted elimination of miCSCs. Moreover, tumor cells show increased susceptibility towards conventional treatment strategies enforcing EPI-X4 derivate as a novel combinatory therapy to treat metastatic pancreatic cancer.

Citation Format: Kanishka Tiwary, Mirja Harms, Bastian Beitzinger, Roman Schmid, Syeda Inaas, Karolin Walter, Alexander Kleger, Mika Lindén, Thomas Seufferlein, Jan Münch, Patrick Christian Hermann. CXCR4 targeting endogenous human peptides eliminate migrating cancer stem cells by disrupting tumor-stroma crosstalk in pancreatic ductal adenocarcinomas [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B034.

Abstract B035: CXCL12 / CXCR4 signaling enhances and sustains migrating cancer stem cells via BMI1 in pancreatic ductal adenocarcinomas

Pancreatic cancer is a fatal disease and is one of the most aggressive and metastatic malignancies worldwide. The dissemination of tumor cells is the prerequisite of metastases and correlates with a loss of epithelial differentiation and the acquisition of a migratory phenotype, a hallmark of malignant tumor progression. Migrating cancer stem cells (miCSCs) characterized by CD133+ and CXCR4+ expression play a pivotal role in malignant tumor formation, have been reported to form the invasive front of the metastasis and in silico analysis showed that both CSCs and miCSCs are significantly upregulated in PDAC. However, the regulatory pattern maintaining these CSCs and especially miCSCs in PDAC remains widely elusive. Thus, this study further helps to unravel pathways responsible for maintenance of CSC (CD133+) and miCSC (CD133+ CXCR4+) population. To identify key signaling pathways responsible for both CSCs and miCSCs maintenance, we first generated a protein-protein interaction network using STRING database. Afterwards, we validated these signaling pathway(s) involved in aiding CSC and miCSC population by performing shRNA mediated knockdown of key signaling proteins in different patient-derived pancreatic cancer cell lines. Moreover, we interrogated the involvement of the tumor-stroma crosstalk in the regulation of these pathways by co-culturing tumor cells with pancreatic stellate cells. Protein-protein interaction network incorporating relevant factors involved in EMT, stemness, as well as SHH, NF-kB and AKT signaling pathway identified a strong link between the CXCL12/CXCR4 signaling axis and BMI1. Migration assay, sphere formation assay and western blot upon shRNA mediated knockdown of either CXCR4 and/or BMI1 ascertained BMI1 as a key player downstream of the CXCL12/CXCR4 axis to mechanistically effect both EMT and stemness. Pathway focused gene expression analysis as well as ELISA and immunofluorescence for CXCL12 and actin filaments, respectively, revealed the indispensable nature of tumor-stroma crosstalk on promoting CSC and miCSC population through the chemokine CXCL12. In addition, co-culture systems revealed that particularly pancreatic stellate cells play a significant role in maintaining both CSCs and miCSCs population as well as their characteristic phenotype including but not limited to chemotherapy resistance. Taken together, our results obtained in this study established mechanistically that the CXCL12/CXCR4 signaling pathway driven by tumor-stroma crosstalk not only enhances but also maintains both CSCs and miCSCs in pancreatic ductal adenocarcinomas through BMI1 ultimately promoting metastases and therapeutic resistance.

Citation Format: Kanishka Tiwary, Anton Lahusen, Syeda Inaas, Stefanie Hauff, Karolin Walter, Alexander Kleger, Thomas Seufferlein, Bruno Sainz Jr., Patrick Christian Hermann. CXCL12 / CXCR4 signaling enhances and sustains migrating cancer stem cells via BMI1 in pancreatic ductal adenocarcinomas [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B035.

Telomerase and Pluripotency Factors Jointly Regulate Stemness in Pancreatic Cancer Stem Cells

To assess the role of telomerase activity and telomere length in pancreatic CSCs we used different CSC enrichment methods (CD133, ALDH, sphere formation) in primary patient-derived pancreatic cancer cells. We show that CSCs have higher telomerase activity and longer telomeres than bulk tumor cells. Inhibition of telomerase activity, using genetic knockdown or pharmacological inhibitor (BIBR1532), resulted in CSC marker depletion, abrogation of sphere formation in vitro and reduced tumorigenicity in vivo. Furthermore, we identify a positive feedback loop between stemness factors (NANOG, OCT3/4, SOX2, KLF4) and telomerase, which is essential for the self-renewal of CSCs. Disruption of the balance between telomerase activity and stemness factors eliminates CSCs via induction of DNA damage and apoptosis in primary patient-derived pancreatic cancer samples, opening future perspectives to avoid CSC-driven tumor relapse. In the present study, we demonstrate that telomerase regulation is critical for the "stemness" maintenance in pancreatic CSCs and examine the effects of telomerase inhibition as a potential treatment option of pancreatic cancer. This may significantly promote our understanding of PDAC tumor biology and may result in improved treatment for pancreatic cancer patients.

Synergistic targeting and resistance to PARP inhibition in DNA damage repair-deficient pancreatic cancer

OBJECTIVE

ATM serine/threonine kinase (ATM) is the most frequently mutated DNA damage response gene, involved in homologous recombination (HR), in pancreatic ductal adenocarcinoma (PDAC).

DESIGN

Combinational synergy screening was performed to endeavour a genotype-tailored targeted therapy.

RESULTS

Synergy was found on inhibition of PARP, ATR and DNA-PKcs (PAD) leading to synthetic lethality in ATM-deficient murine and human PDAC. Mechanistically, PAD-induced PARP trapping, replication fork stalling and mitosis defects leading to P53-mediated apoptosis. Most importantly, chemical inhibition of ATM sensitises human PDAC cells toward PAD with long-term tumour control in vivo. Finally, we anticipated and elucidated PARP inhibitor resistance within the ATM-null background via whole exome sequencing. Arising cells were aneuploid, underwent epithelial-mesenchymal-transition and acquired multidrug resistance (MDR) due to upregulation of drug transporters and a bypass within the DNA repair machinery. These functional observations were mirrored in copy number variations affecting a region on chromosome 5 comprising several of the upregulated MDR genes. Using these findings, we ultimately propose alternative strategies to overcome the resistance.

CONCLUSION

Analysis of the molecular susceptibilities triggered by ATM deficiency in PDAC allow elaboration of an efficient mutation-specific combinational therapeutic approach that can be also implemented in a genotype-independent manner by ATM inhibition.

RINT1 Regulates SUMOylation and the DNA Damage Response to Preserve Cellular Homeostasis in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) still presents with a dismal prognosis despite intense research. Better understanding of cellular homeostasis could identify druggable targets to improve therapy. Here we propose RAD50-interacting protein 1 (RINT1) as an essential mediator of cellular homeostasis in PDAC. In a cohort of resected PDAC, low RINT1 protein expression correlated significantly with better survival. Accordingly, RINT1 depletion caused severe growth defects in vitro associated with accumulation of DNA double-strand breaks (DSB), G₂ cell cycle arrest, disruption of Golgi-endoplasmic reticulum homeostasis, and cell death. Time-resolved transcriptomics corroborated by quantitative proteome and interactome analyses pointed toward defective SUMOylation after RINT1 loss, impairing nucleocytoplasmic transport and DSB response. Subcutaneous xenografts confirmed tumor response by RINT1 depletion, also resulting in a survival benefit when transferred to an orthotopic model. Primary human PDAC organoids licensed RINT1 relevance for cell viability. Taken together, our data indicate that RINT1 loss affects PDAC cell fate by disturbing SUMOylation pathways. Therefore, a RINT1 interference strategy may represent a new putative therapeutic approach. SIGNIFICANCE: These findings provide new insights into the aggressive behavior of PDAC, showing that RINT1 directly correlates with survival in patients with PDAC by disturbing the SUMOylation process, a crucial modification in carcinogenesis.

Exploiting oxidative phosphorylation to promote the stem and immunoevasive properties of pancreatic cancer stem cells

Pancreatic ductal adenocarcinoma (PDAC), the fourth leading cause of cancer death, has a 5-year survival rate of approximately 7-9%. The ineffectiveness of anti-PDAC therapies is believed to be due to the existence of a subpopulation of tumor cells known as cancer stem cells (CSCs), which are functionally plastic, and have exclusive tumorigenic, chemoresistant and metastatic capacities. Herein, we describe a 2D in vitro system for long-term enrichment of pancreatic CSCs that is amenable to biological and CSC-specific studies. By changing the carbon source from glucose to galactose in vitro, we force PDAC cells to utilize OXPHOS, resulting in enrichment of CSCs defined by increased CSC biomarker and pluripotency gene expression, greater tumorigenic potential, induced but reversible quiescence, increased OXPHOS activity, enhanced invasiveness, and upregulated immune evasion properties. This CSC enrichment method can facilitate the discovery of new CSC-specific hallmarks for future development into targets for PDAC-based therapies.

Pancreatic cancer-derived organoids - a disease modeling tool to predict drug response

BACKGROUND

Organotypic cultures derived from pancreatic ductal adenocarcinoma (PDAC) termed pancreatic ductal cancer organoids (PDOs) recapitulate the primary cancer and can be derived from primary or metastatic biopsies. Although isolation and culture of patient-derived pancreatic organoids were established several years ago, pros and cons for individualized medicine have not been comprehensively investigated to date.

METHODS

We conducted a feasibility study, systematically comparing head-to-head patient-derived xenograft tumor (PDX) and PDX-derived organoids by rigorous immunohistochemical and molecular characterization. Subsequently, a drug testing platform was set up and validated in vivo. Patient-derived organoids were investigated as well.

RESULTS

First, PDOs faithfully recapitulated the morphology and marker protein expression patterns of the PDXs. Second, quantitative proteomes from the PDX as well as from corresponding organoid cultures showed high concordance. Third, genomic alterations, as assessed by array-based comparative genomic hybridization, revealed similar results in both groups. Fourth, we established a small-scale pharmacotyping platform adjusted to operate in parallel considering potential obstacles such as culture conditions, timing, drug dosing, and interpretation of the results. In vitro predictions were successfully validated in an in vivo xenograft trial. Translational proof-of-concept is exemplified in a patient with PDAC receiving palliative chemotherapy.

CONCLUSION

Small-scale drug screening in organoids appears to be a feasible, robust and easy-to-handle disease modeling method to allow response predictions in parallel to daily clinical routine. Therefore, our fast and cost-efficient assay is a reasonable approach in a predictive clinical setting.

Optimierung der Bestrahlungsplanung beim nicht-kleinzelligen Bronchialkarzinom (NSCLC) mit Hilfe von 18FDG-PET

Ziel: Die FDG-PET-Untersuchung hat in den vergangenen Jahren bei onkologischen Fragestellungen insbesondere beim Staging des Bronchialkarzinoms wachsende Bedeutung erlangt. In der vorliegenden retrospektiven Untersuchung wurde der Einfluss der PET auf die Strahlentherapieplanung bei Patienten mit non-small-cell lung cancer (NSCLC) untersucht. Methoden: Die Untersuchung umfasste 39 Patienten mit einem NSCLC, die zwecks Staging mit PET untersucht worden waren. Sie wurden über (anhand der CT- und Bronchoskopiebefunde geplante) anterior/posteriore Gegenfelder bestrahlt, die den Primärtumor und das Mediastinum einschlossen. Die Ergebnisse der PET-Untersuchung wurden bei der Bestrahlungsplanung zunächst nicht berücksichtigt. Retrospektiv wurden anhand der FDG-Anreicherungen die Bestrahlungsfelder unter Berücksichtigung der Größe und Lokalisation des Primärtumors neu definiert, weiterhin wurde die Ausdehnung des mediastinalen Anteils der Feldkonturen auf PET-Aktivitäten außerhalb des Bestrahlungsfelds überprüft. Ergebnisse: Bei 15 von 39 Patienten unterschieden sich die CT- von den CT/PET-geplanten Bestrahlungsfeldern. In den meisten Fällen (n = 12) war das CT/PET-Feld kleiner als das CT-Feld. Die mediane Größe der Bestrahlungsfelder betrug 179 cm2 und nach Neudefinition durch PET 166 cm2. Bei 20 Patienten mit Tumor-verursachten Belüftungsstörungen (Atelektasen, Dystelektasen) wurde die Änderung des Bestrahlungsfelds signifikant häufiger (p = 0,03) als bei den übrigen Patienten vorgeschlagen. Schlussfolgerung: Unsere Ergebnisse zeigen den Synergismus von topographischer (CT) und metabolischer (FDG-PET) Information, die in der Bestrahlungsplanung des Bronchialkarzinoms insbesondere bei Patienten mit Belüftungsstörungen von Nutzen sein könnte.

Somatic mutation, copy number and transcriptomic profiles of primary and matched metastatic estrogen receptor-positive breast cancers

BACKGROUND

Estrogen receptor-positive (ER+) breast cancers (BCs) constitute the most frequent BC subtype. The molecular landscape of ER+ relapsed disease is not well characterized. In this study, we aimed to describe the genomic evolution between primary (P) and matched metastatic (M) ER+ BCs after failure of adjuvant therapy.

MATERIALS AND METHODS

A total of 182 ER+ metastatic BC patients with long-term follow-up were identified from a single institution. P tumor tissue was available for all patients, with 88 having matched M material. According to the availability of tumor material, samples were characterized using a 120 mutational hotspot qPCR, a 29 gene copy number aberrations (CNA) and a 400 gene expression panels. ESR1 mutations were assayed by droplet digital PCR. Molecular alterations were correlated with overall survival (OS) using the Cox proportional hazards regression models.

RESULTS

The median follow-up was 6.4 years (range 0.5-26.6 years). Genomic analysis of P tumors revealed somatic mutations in PIK3CA, KRAS, AKT1, FGFR3, HRAS and BRAF at frequencies of 41%, 6%, 5%, 2%, 1% and 2%, respectively, and CN amplification of CCND1, ZNF703, FGFR1, RSF1 and PAK1 at 23%, 19%, 17%, 12% and 11%, respectively. Mutations and CN amplifications were largely concordant between P and matched M (>84%). ESR1 mutations were found in 10.8% of the M but none of the P. Thirteen genes, among which ESR1, FOXA1, and HIF1A, showed significant differential expression between P and M. In P, the differential expression of 18 genes, among which IDO1, was significantly associated with OS (FDR < 0.1).

CONCLUSIONS

Despite the large concordance between P and matched M for the evaluated molecular alterations, potential actionable targets such as ESR1 mutations were found only in M. This supports the importance of characterizing the M disease. Other targets we identified, such as HIF1A and IDO1, warrant further investigation in this patient population.

Synthesis of Peptide-Functionalized Poly(bis-sulfone) Copolymers Regulating HIV-1 Entry and Cancer Stem Cell Migration

Peptide-polymer conjugates have been regarded as primary stronghold in biohybrid nanomedicine, which has seen extensive development due to its intrinsic property to provide complementary functions of both the peptide material and the synthetic polymer platform. Here we present an advanced macromolecular therapeutic that targets two exclusive classes of important diseases (namely, the HIV and cancer) that are implicated by extremely different causative agents. Using a facile thiol-reactive monomer, the eventual polymer facilitates multivalent conjugation of an endogenous peptide WSC02 that targets the CXCR4 chemokine receptor. The biohybrid material demonstrated both potent antiviral effects against HIV-1 as well as inhibiting cancer stem cell migration thus establishing the foundation for multimodal nanotherapeutics that simultaneously target more than one class of disease implications.

Abstract PD6-03: High prevalence and clonal heterogeneity of ESR1 mutations (mt) in circulating tumor DNA (ctDNA) from patients (pts) enrolled in FERGI, a randomized phase II study testing pictilisib (GDC-0941) in combination with fulvestrant (F) in pts that failed a prior aromatase inhibitor (AI)

Background: Mutations in the ligand binding domain of the estrogen receptor gene (ESR1) have been associated with resistance to AI therapy in pts with ER+ breast cancer. To assess if ESR1 status has prognostic or predictive significance in the post-AI metastatic setting ESR1 mutation status was analyzed in circulating tumor DNA (ctDNA) from 168 pts enrolled on the FERGI study (NCT01437566; Krop et al., SABCS 2014).

Methods: Baseline and longitudinal mutational analysis for hotspot mutations in ESR1 (E380Q, S463P, V534E, P535H, L536R/H/P, L536Q, Y537N/S/C, D538G) and PIK3CA (C420R, E542K, E545K/G, Q546K, M1043I, H1047Y/R/L) was performed using droplet digital PCR (ddPCR) on ctDNA derived from plasma. Archival tissue was analyzed via RT-PCR and ddPCR.

Results: Baseline ctDNA analysis demonstrated a total of 62/156 (40%) and 57/153 (37%) pts with PIK3CA and ESR1 mutations, respectively. The most common ESR1 mutations are D538G, Y537S, and E380Q, representing 54%, 33% and 26% of the pts with a detectable ESR1 mutation at baseline, respectively. There was a numeric increase of ESR1 mutations in patients with LumA (41/99, 41%) vs LumB disease (14/44, 31%). PIK3CA mutations in asynchronously collected archival tissue were 85% concordant with plasma ctDNA mutations (sensitivity 78%, specificity 91%). PIK3CA mutations in baseline ctDNA showed a higher median allele frequency (AF) than ESR1 mutations (3.6% vs 0.46%), consistent with PIK3CA being an early event and ESR1 mutations occurring later in pts with recurrent disease. Of the pts with a detectable ESR1 mutation at baseline (n=57), 23 (40%) pts had multiple ESR1 mutations and 10 (18%) had ≥3 ESR1 mutations. The PFS outcomes for patients with and without ESR1 mutations detected at baseline are summarized below, indicating no obvious prognostic or predictive effect for combination of F with pictilisib compared with F in these underpowered subsets.

ArmESR1 MT - mPFS (mo)ESR1 WT - mPFS (mo)HR (95% CI)F + placebo5.4 (30 pts, 24 events)3.7 (40 pts, 31 events)1.06 (0.62, 1.81)F+pictilisib5.8 (27 pts, 20 events)6.7 (56 pts, 34 events)1.36 (0.78, 2.38)

PIK3CA and ESR1 ctDNA analysis on serial plasma samples from 40 pts and the assessment of ESR1 mutation status in the patient's tumor sample by ddPCR is currently in progress and will be reported.

Conclusions: Mutations in ESR1 detected by ddPCR in patient plasma samples occur in nearly 40% of pts that failed a prior AI. The polyclonal nature of ESR1 mutations is consistent with the convergent evolution of multiple AI resistant subclones. While these conclusions should be interpreted with caution due to the relatively small sample size and post hoc nature of the analysis, this data does not support a prognostic or predictive PFS hypothesis for ESR1 mutations with F or in combination with pictilisib.

Citation Format: Spoerke J, Gendreau S, Johnston S, Schmid P, Krop I, Qui J, Derynck M, Chan I, Walter K, Amler L, Hampton G, Lackner M. High prevalence and clonal heterogeneity of ESR1 mutations (mt) in circulating tumor DNA (ctDNA) from patients (pts) enrolled in FERGI, a randomized phase II study testing pictilisib (GDC-0941) in combination with fulvestrant (F) in pts that failed a prior aromatase inhibitor (AI). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD6-03.

Identification of Endoglin as an epigenetically regulated tumour-suppressor gene in lung cancer

Background:

The transforming growth factor-beta (TGF- β) pathway has been implicated in proliferation, migration and invasion of various cancers. Endoglin is a TGF-β accessory receptor that modulates signalling. We identified Endoglin as an epigenetically silenced tumour-suppressor gene in lung cancer by means of a genome-wide screening approach, then sought to characterise its effect on lung cancer progression.

Methods:

Methylation microarray and RNA sequencing were carried out on lung cancer cell lines. Epigenetic silencing of Endoglin was confirmed by methylation and expression analyses. An expression vector and a 20-gene expression panel were used to evaluate Endoglin function. Pyrosequencing was carried out on two independent cohorts comprising 112 and 202 NSCLC cases, respectively, and the impact of Endoglin methylation on overall survival (OS) was evaluated.

Results:

Methylation in the promoter region resulted in silencing of Endoglin, which could be reactivated by demethylation. Increased invasion coupled with altered EMT marker expression was observed in cell lines with an epithelial-like, but not those with a mesenchymal-like, profile when Endoglin was absent. Methylation was associated with decreased OS in stage I but not in stages II–III disease.

Conclusions:

We show that Endoglin is a common target of epigenetic silencing in lung cancer. We reveal a link between Endoglin silencing and EMT progression that might be associated with decreased survival in stage I disease.

Laser Tandem Mass Spectrometry in a Time of Flight Instrument

We present a new laser tandem mass spectrometry technique in a reflectron time of flight (TOF) instrument. A first pulsed laser performs the multiphoton ionization and the primary photodissociation. A newly designed ion source permits a high mass resolution in the space focus of the 12 cm long first linear TOF, where then the secondary excitation can take place. For high resolution applications the pure secondary or pure metastable mass spectrum of a preselected precursor ion can be recorded using a new reflectron scanning technique. It is also possible to obtain the whole secondary mass spectrum with one cycle using a new postacceleration method. Several techniques for ejection of interfering ions are shown. The features of our techniques are demonstrated at various primary fragments of benzene.

Propionic acidemia: neonatal versus selective metabolic screening

BACKGROUND

Whereas propionic acidemia (PA) is a target disease of newborn screening (NBS) in many countries, it is not in others. Data on the benefit of NBS for PA are sparse.

STUDY DESIGN

Twenty PA patients diagnosed through NBS were compared to 35 patients diagnosed by selective metabolic screening (SMS) prompted by clinical findings, family history, or routine laboratory test results. Clinical and biochemical data of patients from 16 metabolic centers in Germany, Austria, and Switzerland were evaluated retrospectively. Additionally, assessment of the intelligent quotient (IQ) was performed. In a second step, the number of PA patients who have died within the past 20 years was estimated based on information provided by the participating metabolic centers.

RESULTS

Patients diagnosed through NBS had neither a milder clinical course regarding the number of metabolic crises nor a better neurological outcome. Among NBS patients, 63% were already symptomatic at the time of diagnosis, and <10% of all patients remained asymptomatic. Among all PA patients, 76% were found to be at least mildly mentally retarded, with an IQ <69. IQ was negatively correlated with the number of metabolic decompensations, but not simply with the patients' age. Physical development was also impaired in the majority of patients. Mortality rates tended to be lower in NBS patients compared with patients diagnosed by SMS.

CONCLUSION

Early diagnosis of PA through NBS seems to be associated with a lower mortality rate. However, no significant benefit could be shown for surviving patients with regard to their clinical course, including the number of metabolic crises, physical and neurocognitive development, and long-term complications.

Mutation analysis in 54 propionic acidemia patients

Deficiency of propionyl CoA carboxylase (PCC), a dodecamer of alpha and beta subunits, causes inherited propionic acidemia. We have studied, at the molecular level, PCC in 54 patients from 48 families comprised of 96 independent alleles. These patients of various ethnic backgrounds came from research centers and hospitals in Germany, Austria and Switzerland. The thorough clinical characterization of these patients was described in the accompanying paper (Grünert et al. 2012). In all 54 patients, many of whom originated from consanguineous families, the entire PCCB gene was examined by genomic DNA sequencing and in 39 individuals the PCCA gene was also studied. In three patients we found mutations in both PCC genes. In addition, in many patients RT-PCR analysis of lymphoblast RNA, lymphoblast enzyme assays, and expression of new mutations in E.coli were carried out. Eight new and eight previously detected mutations were identified in the PCCA gene while 15 new and 13 previously detected mutations were found in the PCCB gene. One missense mutation, p.V288I in the PCCB gene, when expressed in E.coli, yielded 134% of control activity and was consequently classified as a polymorphism in the coding region. Numerous new intronic polymorphisms in both PCC genes were identified. This study adds a considerable amount of new molecular data to the studies of this disease.

STATISTICAL INFORMATION CHARACTERIZATION OF CONSERVED NON-CODING ELEMENTS IN VERTEBRATES

Recently, a set of highly conserved non-coding elements (CNEs) has been derived from a comparison between the genomes of the puffer fish, Takifugu or Fugu rubripes, and man. In order to facilitate the identification of these conserved elements in silico, we characterize them by a number of statistical features.

We found a pronounced information pattern around CNE borders; although the CNEs themselves are AT rich and have high entropy (complexity), they are flanked by GC-rich regions of low entropy (complexity). We also identified the most abundant motifs within and around of CNEs, and identified those that group around their borders. Like in human promoter regions, the TBP, NF-Y and some other binding motifs are clustered around CNE boundaries, which may suggest a possible transcription regulatory function of CNEs.

Tumour epithelial vimentin expression and outcome of pancreatic ductal adenocarcinomas

PURPOSE

Tumour epithelial vimentin expression is a marker of mesenchymal differentiation and may be a useful marker of carcinomas with more aggressive behaviour. The aim of this study was to determine the extent and prognostic significance of vimentin expression in pancreatic ductal adenocarcinomas.

METHODS

Vimentin expression was detected by immunohistochemistry on tissue microarrays of surgically resected pancreatic ductal adenocarcinomas from 387 patients. The percentage of vimentin-immunolabelled neoplastic cells was correlated with outcome and with clinico-pathological factors using the Kaplan-Meier method and Cox multivariate survival models.

RESULTS

In all, 45% of primary pancreatic adenocarcinomas contained neoplastic cells that expressed vimentin, and in 27.5% of the cancers >10% of cells expressed vimentin. Vimentin expression was correlated with poor histological differentiation. By both uni- and multivariate survival analysis, neoplastic vimentin expression (P<0.01, HR 1.52, 95% confidence interval 1.14-2.04) was an indicator of a shorter postsurgical survival independent of other clinico-pathological variables.

CONCLUSION

The presence of vimentin-expressing tumour epithelial cells in surgically resected pancreatic adenocarcinomas independently predicted a shorter postsurgical survival.

Balloon valvuloplasty in the treatment of congenital aortic valve stenosis--a retrospective multicenter survey of more than 1000 patients

BACKGROUND

The value of balloon valvuloplasty of the aortic valve in childhood is still under debate.

OBJECTIVE

To evaluate the results of the procedure in a retrospective multicenter survey of a large cohort over a long time interval.

METHODS

Retrospective analysis of 1004 patients with balloon valvuloplasty of the aortic valve performed between 9/1985 and 10/2006 at 20 centers in Germany, Austria and Switzerland. Amongst others, the following parameters were evaluated before and after the procedure as well as at the end of follow-up or before surgery: clinical status, left ventricular function, transaortic pressure gradient, degree of aortic regurgitation, freedom from re-intervention or surgery.

PATIENTS

Patients from 1 day to 18 years of age with aortic valve stenosis were divided into four groups: 334 newborns (1-28 days); 249 infants (29-365 days); 211 children (1-10 years), and 210 adolescents (10-18 years).

RESULTS

Median follow-up was 32 months (0 days to 17.5 years). After dilatation the pressure gradient decreased from 65 (± 24)mm Hg to 26 (± 16)mm Hg and remained stable during follow-up. The newborns were the most affected patients. Approximately 60% of them had clinical symptoms and impaired left ventricular function before intervention. Complication rate was 15% in newborns, 11% in infants and 6% in older children. Independently of age, 50% of all patients were free from surgery 10 years after intervention.

CONCLUSIONS

In this retrospective multicenter study, balloon valvuloplasty of the aortic valve has effectively postponed the need for surgery in infants, children and adolescents up to 18 years of age.

Imaging findings in a 3-year-old girl with type III pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare dysembryonic intrathoracic neoplasm in children. It is a malignant tumour originating from the mesenchyme with a poor prognosis. We report on a 3-year-old girl who presented with respiratory symptoms and was diagnosed as having a type III PPB according to histological results attained by open biopsy. Imaging by CT and MRI revealed the exact size of the tumour involving the left lower lobe with displacement of the mediastinum and the diaphragm. Additional FDG-PET was important to evaluate tumour vitality and to decide the time of surgery, which was performed after 12 weeks of chemotherapy with the CWS2002P protocol. After R0 resection without complications and postoperative chemotherapy, the child continues to be in complete remission. This case underlines the importance of radical surgery of the aggressive neoplasm in combination with chemotherapy and the usefulness of multimodal imaging for the optimal planning of local therapy.

[Fabry disease: demographic data since introduction of enzyme replacement therapy]

BACKGROUND AND OBJECTIVE

Fabry's disease is a rare, X-chromosome linked recessive lysosomal storage disorder. In its course multiple organ damage occurs, e.g. in skin, nerves, kidneys and heart. The disease not only markedly impairs the quality of life but also shortens life expectancy if untreated. As it is a rare and not widely known disease with considerable variability of its symptoms it is often not or only belatedly diagnosed. Since 2001, enzyme replacement has become available as an option in the causal treatment. It was the aim of this study to analyse the demography and clinical expression of the disease.

PATIENTS AND METHODS

Data were obtained from the Fabry Outcome Survey (FOS), a Europe-wide data bank for the documentation of the disease's clinical course, on 262 patients (130 males, 132 females; mean age 37.5 and 34 years, respectively on entry in the FOS) in Germany, Switzerland and Austria.

RESULTS

Typical symptoms - acroparesthesias, joint pain, hypohidrosis, fever and angiokeratoma - have their onset in childhood (mean age nine years). Symptoms start significantly earlier in males than females. The interval between onset of the first symptoms and establishment of the diagnosis is about 15 years. The severity of the clinical picture, as measured in the POS Mainz severity score index (MSSI), correlates significantly with the person's age (p = 0.0001). Main causes of morbidity and death in Fabry's disease are involvement of the kidneys or heart, the one or other occurring in 75% of patients. 171 patients (38 [65.3%]: 92 males, 79 females) are at present being continually treated with enzyme-replacement (ERT), agalsidase-a, i.e. 70.8% of all male and 59.8 of all female patients in the FOS.

CONCLUSIONS

It is of great importance for the prognosis and quality that Fabry's disease is diagnosed as early as possible and treated adequately before the onset of organ damage. If the listed symptoms by themselves remain unexplained, Fabry's disease should be considered in the differential diagnosis. National and international observational studies, such as the FOS, significantly contribute to gaining important clinical data on this heterogeneous disease.

Non-invasive assessment of tumor proliferation using triple quantum filtered 23/Na MRI: technical challenges and solutions

We address the development of triple-quantum-filtered sodium MRI as a non-invasive surrogate measure for cell proliferation in brain tumors. We demonstrate that through careful consideration of the theoretical description of the signal, triple-quantum-filtered sodium images of adequate signal-to-noise ratio (SNR) can be acquired in clinically acceptable imaging times.