Projects / Programmes
Regulation of Primary Metabolism in Cancer Cells
| Code |
Science |
Field |
Subfield |
| 4.06.00 |
Biotechnical sciences |
Biotechnology |
|
| Code |
Science |
Field |
| T490 |
Technological sciences |
Biotechnology |
regulation of metabolism, 6-phosphofructo-1-kinase, glycolysis, posttranslational modification, cancer
Researchers (4)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
14360 |
PhD Mojca Benčina |
Biotechnology |
Researcher |
2007 - 2009 |
392 |
| 2. |
09354 |
PhD Matic Legiša |
Biotechnology |
Head |
2007 - 2009 |
272 |
| 3. |
17280 |
Darija Oven |
|
Technical associate |
2007 - 2009 |
4 |
| 4. |
29490 |
MSc Andreja Šmerc |
Biochemistry and molecular biology |
Junior researcher |
2009 |
10 |
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
0104 |
National Institute of Chemistry |
Ljubljana |
5051592000 |
21,007 |
Abstract
By studiyng metabolic regulation of industrial fungus Aspergillus niger, we were first to describe the cause of de-regulated glycolysis, leading to strong anaplerotic reactions and increased anabolic reactions. We proposed that 6-phosphofructo-1-kinase (PFK1), the key regulatory enzyme of glycolytic pathway is posttranslationally modified and a shorter fragment is formed after the cleavage of a part of native protein by specific proteases. Newly processed enzyme remained active, however its kinetics was changed. It was insensitive to the usual allosteric inhibitors, ATP and citrate but became highly sensitive to specific activators. Undisturbed metabolic flux through glycolysis was characteristic for cells harbouring modiefied PFK1 enzyme, leading to increased level of tricarboxylic acid cycle intermediates, increased anabolic reactions and consequently increased productivity of various biotechnological products.
In March 2006 a paper was published describing unregulated metabolic flux of glycolysis in neopastic hepatoma cells, with no usual control present at the level of PFK1 enzyme. By measuring PFK1 enzyme kinetics the protein seemed to be resistant to inhibitors, ATP and citrate, yet highly sensitive to the activators NH4+, AMP, and fructose-2,6-biphosphate (Marin-Hernandez, 2006).
For the cancer cells increased de-regulated glycolysis is characteristic, while respiration pathway is malfunctioning. Therefore, in the neoplastic cells ATP is largely formed from glycolysis. Although cancer is ultimately a disease of genes, oncogene induction causes significant changes at the level of metabolism, which are not adequately understood.
By the proposed project we are going to show that posttranslational modification of PFK1 is a significant phenomenon taking part at the transformation of normal cells into neoplastic cells. This effect causes de-regulated metabolic flux through glycolysis, increased anaplerotic reactions that result in more rapid anabolic reactions and finally accelerate cell proliferation.
Clarification of this physiological effect in cancer cells will significantly contribute to understanding of the disease and might well present a new target for the inhibition of cancer proliferation by adequate medicaments.
Significance for science
The switch from oxidative phosphorylation to glycolytic metabolism (Warburg effect) is consistent characteristic of malignant cells. Deviant energetic metabolism of cancer cells has been even discussed as a potential hallmark or sign of cancer. The crucial factors recognised so far behind the cancer metabolic phenotype seem to be increased activities of transcription factors c-MYC and HIF-1 that induce higher expression of glycolytic enzymes. Although synthesising more wild-type enzymes would increase their specific activities, they would retain the ability to be regulated. One is forced to conclude therefore, that important changes at the level of regulation of allosteric enzymes must be involved in the changes in metabolism. The most important enzyme in this respect seems to be 6-phosphofructo-1-kinase (PFK1), which catalyses one of the three irreversible reactions of glycolysis. The description of posttranslational modification of PFK1 enzyme in cancer cells that causes the formation of a highly active, citrate inhibition resistant shorter fragment of the enzyme is of out most importance for comprehending the metabolic changes in cancer cells. Due to extreme instability of the shorter PFK1 fragment under the in vitro conditions, the enzyme might become an appropriate target for uncoupling deviant energetic metabolism of cancer cell.
Significance for the country
Cancer as a disease affects all people and Slovenians are no exception. According to the data provided by the Statistic Office, there are more than 10.000 new cases of cancer discovered annually in Slovenia. Therefore, the research in this field is of extreme importance. Originally we were involved in metabolic studies of industrial microorganisms, where posttranslational modification of 6-phosphofructo-1-kinase was first described at filamentous fungus Aspergillus niger. Later on a similar process seemed to be feasible also for the cancer cells. The results so far achieved by this project confirmed the accuracy of the hypothesis. Although much research has been focused on the studies of the Warburg effect at the metabolic regulation level worldwide in past, the formation of the highly active shorter PFK1 fragment was overlooked, most probably due to the extreme instability of the modified enzyme under the in vitro conditions. It seems, we are the only laboratory worldwide momentary possessing the technology for measuring its enzyme activity. Although the focus of metabolic research in cancer has shifted form the studies of enzyme regulation to the studies of signalling pathways in last decade, we believe that publication of our results on posttranslational modification of PFK1 enzyme might significantly contribute to the understanding of the Warburg effect. We expect that our work will adequately promote Slovenian science worldwide.
Most important scientific results
Annual report
2008,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
final report,
complete report on dLib.si
