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| Poster, Friday, 19:00 |
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| Identification of SEC62 as
a new migration stimulating oncogene in human lung cancer
Maximilian Linxweiler1,
Johannes Linxweiler1, Markus Greiner1, Monika Barth1,
Birgit Klemmer2, Anika Müller1, Sven Lang1,
Rainer Bohle3, Rainer Grobholz4, Gerhard Unteregger2,
Volker Jung2, Bernd Wullich5, Richard Zimmermann1
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1
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Universität des Saarlandes,
Institut für Medizinische Biochemie und Molekularbiologie, Homburg
Germany |
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2
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Universitätsklinikum des Saarlandes,
Klinik für Urologie u. Kinderurologie, Homburg/Saar, Germany |
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3
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Universitätsklinikum des Saarlandes,
Institut für Allgemeine und Spezielle Pathologie, Homburg, Germany |
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4
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Kantonsspital Aarau, Pathologie,
Aarau, Switzerland |
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5
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Universitätsklinikum Erlangen,
Klinik für Urologie, Erlangen, Germany |
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| Contact:
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We previously reported an amplification of the SEC62 gene, a higher
SEC62 mRNA and Sec62 protein content in prostate cancer cell lines as well
as tissue samples. In a multi-tissue-tumor-microarray, we found a significantly
increased Sec62 level in lung and thyroid cancer tissue samples compared
to tumor free tissue of the same organs.
Based on these promising results, we analyzed the Sec62 mRNA and protein
level in tissue samples from 70 lung cancer patients by qRT-PCR, Western
Blot as well as immunhistochemistry and found a significantly increased
Sec62 protein (p<0.0001) and mRNA content (p<0.05) in tumor- compared
to tumor-free lung samples of the same patients. Correlation analyses showed
a significantly higher Sec62 content in tumors with lymph node metastases
compared to tumors having not metastasized (p<0.05) as well as in low-
(G3) compared to middle-differentiated tumors (G2, p<0.005). To further
examine the role of Sec62 in cancer cell biology, functional cell culture
experiments were performed. In Real time proliferation assays and migration
analyses the silencing of SEC62 by siRNA lead to a distinct inhibition
of the cells’ migratory potential whereas cell proliferation was not affected.
This effect could be shown for prostate (PC3), cervix (HeLa), thyroid (BHT101,
ML1) and lung cancer cells (A549, H1299, BC01). To find out if accordingly
an overexpression of the SEC62-gene induced by plasmid transfection stimulates
the migration of human cancer cells, we performed migration assays comparing
HEK293 wild-type cells with SEC62-overexpressing cells. Indeed, we could
show that the increase of Sec62 protein level up to the 10-fold by plasmid
transfection compared to wild-type cells resulted in a distinct stimulation
of migratory potential of the otherwise not migrating HEK293 cells. These
results confirmed the above mentioned correlation data based on the analysis
of the Sec62-protein level in human lung cancer tissue samples where we
found a higher Sec62-level in metastasized compared to not-metastasized
tumors. As we could also find a correlation with the dedifferentiation
of the tumor cells, Sec62 presents a promising new prognostic marker in
human lung cancer. Additionally, a Sec62-depletion in human cancer cells
as described in this work in vitro could also form a new therapeutic
approach for the treatment of various cancer entities as the use of small
RNA in cancer therapy is frequently discussed. All things considered
and with regard to the entire field of molecular oncology one more player
in the complex network of tumor cell biology could thus be identified,
characterized in its functional role within carcinogenesis and cancer cell
biology and evaluated in its relevance as a potential prognostic marker
and therapeutic target in lung cancer. |
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