96. Jahrestagung der Deutschen Gesellschaft für Pathologie e. V ...

Abstracts
SG-P-132
SiRNA inhibition of Shp-2 reduces the GC phenotype of Burkitt’s
lymphoma cell lines
X . Jiang 1 , R . Zhou 1 , L . He 1 , C . He 1 , J . Wang 1
1 Zhejiang University, School of Medicine, Hangzhou, China
Aims. To investigate the potential role of Shp2 in the GC phenotype regulation
of BL cell lines.
Methods. We used either scrambled siRNA or Shp2 siRNA pools to
transfect human BL cell lines (Daudi, Raji, Ramos). We also expressed
a PTP-inactive Shp2 mutant (Shp2CS) that had the catalytic Cys-459 replaced
with Ser in Raji cells to verify whether the Shp2 PTP activity is required
in BL cells growth. And we analyzed the effects of Src inhibitor-1
(Sigma) and Mek inhibitors (U0126) in BL cells.
Results. Shp2 had been effectively silenced by the Shp-2 siRNA. Shp2
knockdown led to a decrease in Erk1/2 phosphorylation. Concomitantly,
we observed a decrease in the phosphorylation of the tyrosine residue
Y416 in the activation loop of Src, whereas Stat3 and Akt phosphorylations
were not affected. Similar to Shp2 knockdown in BL cell lines, the
C/S protein in Raji cells inhibited ERK1/2 and Src phosphorylation. The
abrogation of Shp2 in both cell lines significantly impaired cellular proliferation
over time compared with cells grown to the control cell lines.
Cell cycle analysis revealed that Shp2 knock down led to a significant
increase in the percentage of BL cells in the G1 phase and a corresponding
decrease in the S and G2-M phases, without changes in the apoptotic
fraction as indicated by the sub-G0-G1 populations. Thus knockdown
of Shp2 significantly inhibited BL tumor growth. We also found
that shp2 inhibition led to a decrease in CD77 positivity in BL cell lines.
Concomitantly, the protein levels of Bcl-6, E2A, AID and Pax-5 were
substantially lower in Shp2-siRNA BL cells than in their Shp2-positive
counterparts. Biochemical analysis also showed that Shp2 knockdown
resulted in down-regulation of c-Myc in BL cells. And Src inhibitor-1 and
U0126 caused decreases of c-Myc and GC factors as CD77, Bcl-6, AID,
E2A and Pax-5 expression level in BL cells. These results indicate that
Src and Erk1/2 activities are necessary for a constitutive GC phenotype
in BL cells.
Conclusions. In this study, we showed that Shp2 regulated BL cells proliferation
in cell culture. Reduction of Shp2 expression led to a decrease
of c-Myc and GC factors (Bcl-6, E2A, AID and Pax-5) in BL cell lines
through Src and Erk1/2 pathway, which suggested Shp2 play a key role in
the series of regulative factors of the GC phenotype in BL cells.
Keywords. Shp2, Burkitt’s lymphoma, GC phenotype
Grants. the NSF of Zhejiang Province (No.Y2090167) and Research Foundation
in Zhejiang Scientific and Technical Bureau (No.2009C33039).
SG-P-133
Identification of lymphoma subtype independent micro RNA
expression profiles
D . Lenze1 *, M .R . Schweiger2 *, M . Piechotta 3 , K . Zimmermann4 , A . Fischer2 ,
S . Boerno2 , C . Dieterich3 , U . Leser4 , M . Hummel1 1 2 Charité – Universitätsmedizin Berlin, Institute of Pathology, Berlin, Max
Planck Institute for Molecular Genetics, Berlin, 3Max-Delbrueck-Center for
Molecular Medicine, Institute for Medical Systems Biology, Berlin, 4Hum boldt-University, Institute for Informatics, Berlin
Aims. The molecular analyses of human cancers revealed that great heterogeneity
on the molecular level exists even within the same tumor
entity which might explain different therapeutic outcome to the same
type of treatment. This holds also true for lymphoma. Therefore it is justified
to assume that lymphomas carrying the same molecular features
might benefit from the same targeted treatment modalities irrespective
of their histological or immunophenotypical features. It was the goal of
our study to identify overlapping molecular characteristics in a variety
of histologically defined lymphoma entities. To achieve this goal, comprehensive
expression profiles of non-coding and coding transcripts de-
94 | Der Pathologe · Supplement 1 · 2012
rived from a broad spectrum of lymphomas were established. Our data
show that overlapping molecular features can be identified beyond the
current lymphoma classification.
Methods. RNA was extracted from frozen tissue blocks of distinct human
B- and T-cell lymphoma entities as well as tonsils (n=116). The small
(micro) RNA fraction was sequenced by next generation technology
(SOLiD) and total RNA was subjected to Affymetrix Exon 1.0 ST array
hybridisation. In addition immunohistochemical and clinical data was
acquired. Bioinformatic analyses were then applied for subgroup detection.
Results. Unsupervised clustering based on the mature micro RNA expression
derived from deep sequencing demonstrated the presence of
two distinct large clusters within the case collection. One cluster contained
predominantly the so-called indolent lymphoma types, but also a
considerable number of aggressive B-cell lymphoma cases. In the second
cluster the majority of cases were aggressive B-cell lymphoma but interestingly
intermingled with the T-cell lymphoma cases. Differentially
expressed micro RNAs between the two clusters were determined and
logistic regression identified a micro RNA classificator able to distinguish
the two groups. The micro RNA expression data was combined with
the coding RNA data in order to identify the involved pathways.
Conclusions. Micro RNA expression profiles obtained by deep sequencing
were able to identify two groups within a lymphoma collection that
separated the cases beyond the histopathological classification system.
Discriminative micro RNAs and associated pathways were identified.
These findings give new insights into lymphoma biology and point to
alternative treatment options.
*These authors contributed equally to the study .
Poster: GI-Trakt: Ösophagus, Magen
FR-P-036
Acanthosis nigricans: a paraneoplastic condition of the esophagus
D . Karimi1 , J . Siveke2 , M . Ringelhahn2 , M . Bettstetter3 , M . Sarbia1 1 2 Pathology München-Nord, Department of Gastroenterology Technical
University München, 3Institute of Molecular Pathology Südbayern
Aims. Presentation of endoskopic and histologic findings of esophageal
acanthosis nigricans.
Methods. The case of a 69-year-old man with dysphagia and weight loss
will be presented.
Results. Endoscopic examination revealed an adenocarcinoma of the
esophagogastric junction as well as multiple small polyps in the middle
and the lower thirds of the esophagus. Histological examination showed
papilloma-like proliferations without atypia, which were diagnosed as
acanthosis nigricans of the esophagus. After completion of the staging
investigation regarding the cardiac carcinoma, combination chemotherapy
was started because of the presence of liver metastases. Subsequently,
partial regression of the carcinoma as well as of the esophageal lesions
was noted.
Conclusions. Acanthosis nigricans is a rare paraneoplastic disease of the
esophagus. As an indicator lesion, its detection should prompt a search
for a malignant tumor in the gastrointestinal tract.