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Identification of drug-regulated genes in osteosarcoma cells
Jörg Fellenberg1, Markus J Dechant, Volker Ewerbeck
1Stiftung Orthopädische Universitätsklinik, Schlierbacher Landstrasse 200a, 69118 Heidelberg, Germany. joerg.fellenberg@ok.uni-heidelberg.de
Abstract:
The introduction of systemic chemotherapy improved significantly the prognosis of osteosarcoma. Despite this success, approximately 30-40% of patients will relapse. Cytotoxic drugs have been shown to induce apoptosis in the target cells independent of their primary effects. The underlying molecular mechanisms and the intracellular mediators, however, are still largely unknown. Therefore, the purpose of our study was to identify drug-regulated genes in osteosarcoma cells useful as prognostic factors and for the development of new therapeutic strategies. Using suppressive subtractive hybridization (SSH) the gene expression pattern of untreated Saos-2 cells was compared to cells treated with cisplatin, methotrexate and doxorubicin, respectively. We identified 8 genes that are regulated >2-fold in drug-treated osteosarcoma cell lines. Expression of ferritin light chain, rhoA, inosine monophosphatdgehydrogenase II, ribonucleotide reductase M2, pro2000 and pro1859 were increased after drug treatment, whereas prohibitin and alpha-actinin expressions were significantly downregulated. Differential expression of the identified genes was verified by Northern blot analysis of 3 different osteosarcoma cell lines. In addition, the effects on chemosensitivity of 4 selected genes was analyzed by overexpression of recombinant constructs in Saos-2 cells and subsequent quantification of drug-induced apoptosis. Overexpression of prohibitin and rhoA reduced significantly drug sensitivity to approximately 52% and 59% indicating a crucial role in the modulation of drug-induced cell death.
Insights
Chemotherapy improves osteosarcoma outcomes, but relapses occur. This study identified key genes like prohibitin and rhoA that influence drug-induced cell death, offering new therapeutic targets for osteosarcoma treatment.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Systemic chemotherapy has improved osteosarcoma prognosis, yet 30-40% of patients relapse.
- The molecular mechanisms and intracellular mediators of drug-induced apoptosis in osteosarcoma remain largely unknown.
Purpose of the Study:
- To identify drug-regulated genes in osteosarcoma cells.
- To find potential prognostic factors and novel therapeutic targets for osteosarcoma.
Main Methods:
- Suppresssive subtractive hybridization (SSH) was used to compare gene expression in untreated and drug-treated Saos-2 cells (cisplatin, methotrexate, doxorubicin).
- Differential gene expression was validated using Northern blot analysis.
- The impact of selected genes on chemosensitivity was assessed via gene overexpression and apoptosis quantification.
Main Results:
- Eight genes showed >2-fold regulation in drug-treated osteosarcoma cells.
- Ferritin light chain, rhoA, inosine monophosphate dehydrogenase II, ribonucleotide reductase M2, pro2000, and pro1859 expression increased.
- Prohibitin and alpha-actinin expression decreased.
- Overexpression of prohibitin and rhoA significantly reduced drug sensitivity, indicating their role in modulating drug-induced cell death.
Conclusions:
- Prohibitin and rhoA play crucial roles in modulating drug-induced apoptosis in osteosarcoma.
- These genes represent potential prognostic markers and therapeutic targets for improving osteosarcoma treatment outcomes.