Leiden biophysicist Stefano Coppola has received the prestigious AXA Research Fund postdoctoral fellowship. With this grant he can work for two years on a project to research the role of mechanical factors in the development of pancreatic cancer.
the deadliest of all solid tumors. Doctors usually perform the diagnosis when the cancer has already metastasized. Because of the complexity and variety of metastatic pancreatic cancer, it is virtually impossible to cure. The best hope for reducing the mortality rate of pancreatic cancer lies in the diagnosis and treatment in the early stages.
There is persuasive evidence from other types of tumors that mechanical cues are connected with cancer progression. These could be mechanical pressure, stress or strain. On the one hand, a tumor causes its environment to become stiffer. On the other hand, a tumor changes how cells sense the mechanical cues, like stiffness, that are present.
During his fellowship, Coppola will investigate the processes that drive the initiation and progression of a specific type of mechanical distortion in the pancreas, called PanIN. It is well known that significant mechanical stress is a hallmark feature of pancreatic cancer. However, the way in which cells convert mechanical stimuli into biomolecular activity has so far been unexplored for pancreatic cancer. Coppola hypothesizes that mechanical cues represent a novel early and label-free diagnostic biomarker to explain how pancreatic cancer progresses.
Together with principal investigator Thomas Schmidt, Coppola will study the mechanical phenotypes of PanIN-damaged cells compared to normal pancreatic cells, by applying external forces on them and by observing forces exerted by cells on their surroundings. Understanding the role of force and mechanics in a developing tumor might eventually lead to novel molecular targeted therapies to predict and temper risks in early pancreatic cancer.
Leiden theoretical physicists have proven that not only the genetic information in DNA determines who we are, but also DNA’s mechanics. Helmut Schiessel and his group simulated many DNA sequences and found a correlation between mechanical cues and the way More info
When James Watson and Francis Crick identified the structure of DNA molecules in 1953, they revealed the way in which DNA contains the information that determines who we are. The sequence of the letters G, A, T and C in the famous double helix determines what proteins are made within our body. If you have brown eyes for example, this is because a series of letters in your DNA encodes for proteins that build brown eyes. Still, each cell in our body contains the exact same letter sequence, and yet every organ behaves differently. How is this possible?
Since the mid 80s it has been hypothesized that there is a second layer of information on top of the genetic code: DNA’s mechanical properties. Each of our cells contains two meters of DNA molecules, so these molecules need to be wrapped up tightly to fit inside a single cell. The way in which DNA is folded, determines how the letters are read out, and therefore which proteins are actually made. In each organ, only relevant parts of the genetic information are read, based on how the DNA is folded. The theory goes that mechanical cues within the DNA structures determine how DNA prefers to fold.
Now for the first time, Leiden physicist Helmut Schiessel and his research group provide strong evidence that this second layer of information indeed exists. With their computer code they have simulated the folding of DNA strands with randomly assigned mechanical cues. It turns out that these cues indeed determine how the DNA molecule is folded into so-called nucleosomes. Schiessel found correlations between the mechanics and the actual folding structure in the genome of two organisms—baker’s yeast and fission yeast. With this finding we know that evolutionary changes in DNA—mutations—can have two very different effects: the letter sequence encoding for a specific protein can change or the mechanics of the DNA structure can change, resulting in a different packaging and accessibility of the DNA and therefore a different frequency of production of that protein.
The painting of the Einstein field equation on the front wall of Museum Boerhaave is now upgraded with an illustration. Last November, the equation was officially launched as the first of ten formulas that will be painted on More info
walls around the Leiden city center, alongside the already existing wall poems.
On the illustration, we see light from a distant object traveling to Earth. Along the way it is bent by the curved spacetime around the Sun. This is exactly what the Einstein field equation tells us; mass and energy manifest themselves through gravity by curving spacetime in its vicinity. In 1919, the corresponding general theory of relativity was tested using the Sun as a laboratory, in a similar setup as the illustration depicts. During a solar eclipse, Arthur Eddington measured the position of the Hyades star cluster, which was in the same place on the sky at that moment. If massive objects bend spacetime, and starlight consequently follows a curved path around them, then the Hyades cluster should be visible at a slightly different position, as its light passes through spacetime close to the Sun. And indeed, this is what Eddington measured, producing the first experimental evidence of Einstein’s theory of general relativity and his field equations.
A. Vinante, M. Bahrami, A. Bassi, O. Usenko, G. Wijts, T.H. Oosterkamp (2016) Upper bounds on spontaneous wave-function collapse models using millikelvin-cooled nanocantilevers, Phys. Rev. Lett., 3, 116, 090402. [DOI][pdf]
Jan van Ruitenbeek (2016) Molecular machines and devices, Beilstein Journal, 7, 310-311. [DOI][pdf]
28 June, 11:15, Academy building, Rapenburg 73
Thesis Defense Willem George Onderwaater - Interface Physics: CO Oxidation Catalysis at Multiple Length Scales Promotor: Prof.dr. J.W.M. Frenken, co-promotor: Dr. R. Felici
29 June, 16:15, Academy building, Rapenburg 73
Thesis defense Matthijs van Spronsen - Interfase Physics: Oxidation Catalysis on Pt and Au Complexity of Simple Chemistry Promotor: Prof.dr. J.W.M. Frenken, co-promotores: Dr. M.N. Groot, Dr. L.B.F. Juurlink
30 June, 09:00, HL 106
BSM Seminar Noémie Berenger-Currias: Cell adhesion molecules and cell sorting: towards the spatial control of artificial tissues