Breaking News
March 25, 2018 - Humanigen Completes Enrollment of Phase 1 Clinical Trial of Lenzilumab for Treatment of Chronic Myelomonocytic Leukemia
March 25, 2018 - ENDO 2018 Roundup: New Tx Options for Obesity, Low BMD, Benign Thyroid Disease
March 25, 2018 - The protein that prevents loose teeth
March 24, 2018 - Morning Break: Skip the Finger Exam? Self C-Section; Toxic Toenail Fungus
March 24, 2018 - 3-D simulations reveal synergistic mechanisms of the human heart
March 24, 2018 - Newly designed three-part molecule shows promise to treat breast cancers
March 24, 2018 - Pubertal hormones not responsible for changes in social behavior during adolescence
March 24, 2018 - Waning Vaccine Protection May Be Driving Rise in U.S. Mumps Cases
March 24, 2018 - Folic Acid in Utero Tied to Food Allergy Risk
March 24, 2018 - Trial shows safety of drugs for irregular heartbeat patients undergoing treatment
March 24, 2018 - Penn State psychologists shed light on false memories in older adults
March 24, 2018 - Patients who self-discharge should be viewed more positively, say researchers
March 24, 2018 - Wearable brain scanner enables brain imaging whilst moving
March 24, 2018 - Trump Signs $1.3 Trillion Spending Bill, Averts Shutdown
March 24, 2018 - Two drugs prevent heart problems in breast cancer patients
March 24, 2018 - Research provides better understanding of how some cancer cells resist treatment
March 24, 2018 - Certain nutrients found in food may help reduce symptoms of psychotic illness
March 24, 2018 - AbbVie Announces Positive Topline Results from Second Phase 3 Study Evaluating Investigational Elagolix in Women with Uterine Fibroids
March 24, 2018 - AHRQ Is in Trouble | Medpage Today
March 24, 2018 - Could a pap test spot more than just cervical cancer?
March 24, 2018 - Men have greater hospital readmission risk following firearm injury, study shows
March 24, 2018 - Pediatric psychologist shares 11 warning signs of childhood depression
March 24, 2018 - OncoBreak: ‘I Was Normal Once’; Ending Cervical Cancer; Mammo Controversy
March 24, 2018 - Gum Disease by the Numbers
March 24, 2018 - Studies show tool can identify individual needs, supports to help youths with autism, intellectual disabilities
March 24, 2018 - Study reveals cause of extreme nausea in pregnancy
March 24, 2018 - New findings highlight need to reconsider cervical cancer screening guidelines
March 24, 2018 - Smartwatch App Might Help Detect A-Fib
March 24, 2018 - TAVR Reasonable for Low-Flow, Low-Gradient Aortic Stenosis
March 24, 2018 - Kids with severe brain injuries may develop ADHD: study
March 24, 2018 - Researchers explore ways to help older adults taper off and stop using sedatives
March 24, 2018 - Back pain being mismanaged globally
March 24, 2018 - Fingerprint test accurately and noninvasively detects heroin, cocaine users
March 24, 2018 - Leading experts to promote cardiovascular health at EuroPrevent 2018
March 24, 2018 - A Role for Rituximab in Lupus?
March 24, 2018 - New osteoarthritis genes discovered
March 24, 2018 - Maternal intake of DHA supplement linked to higher fat-free body mass in children
March 24, 2018 - Royal College of Pathologists‘ bulletin provides summary of Tissue Handling Workshop
March 24, 2018 - Maternal alcohol use early in pregnancy may be risk factor for infant abdominal malformation
March 24, 2018 - Savara Initiates Phase 2a Clinical Study of Molgradex for the Treatment of NTM Lung Infection
March 24, 2018 - Accelerated WBI Should be the Norm for Most Breast Cancers
March 24, 2018 - Experts seek to standardize treatments for childhood rheumatic diseases
March 24, 2018 - Foil-based measuring chip rapidly detects Legionella
March 24, 2018 - Bariatric surgery linked to positive outcomes in very obese adolescents with type 2 diabetes
March 24, 2018 - Researchers identify chemical responsible for carcinogen formation in recycled wastewater
March 24, 2018 - Obesity and severe obesity continue to rise among U.S. adults
March 24, 2018 - Missed hospital appointments increase after spring clock change in the UK
March 24, 2018 - Researchers explore ways to manage and prevent falls in older adults with dementia
March 24, 2018 - Are there risks from secondhand marijuana smoke? Early science says yes.
March 24, 2018 - NUST MISIS researchers produce elastic metal rods for scoliosis treatment
March 24, 2018 - New University of Bath project seeks to make injections safer
March 24, 2018 - Higher-dose RT does not improve survival but reduces recurrence risk for prostate cancer patients
March 24, 2018 - Researchers examine link between knee pain and depression in older adults
March 24, 2018 - FDA Alert: BD Vacutainer Blood Collection Tubes by Becton, Dickinson and Company (BD): Class I Recall
March 24, 2018 - Daytime Sleepiness Linked to Amyloid Accumulation Without Dementia
March 24, 2018 - Energy storehouses in the brain may be source of Alzheimer’s, targets of new therapy
March 24, 2018 - Praising people with autism shows promise for producing more exercise
March 24, 2018 - Using harmless red or infrared light to diagnose breast cancer
March 24, 2018 - Clash over abortion hobbles a health bill. Again. Here’s how.
March 23, 2018 - Virtual nature environment could be new way to recover from stress
March 23, 2018 - New study identifies key cellular mechanisms behind vascular aging in mice
March 23, 2018 - Nightmares Common Among U.S. Troops, But Seldom Reported
March 23, 2018 - Another Record Low for Tuberculosis in U.S.
March 23, 2018 - Changes in the eye connected to a decline in memory
March 23, 2018 - Radiologist creates dramatic teaching tool using power of VR
March 23, 2018 - Grilled meat could be raising the risk of hypertension finds study
March 23, 2018 - Mutations found in bassoon gene may help explain cause of rare brain disorder
March 23, 2018 - Childhood Brain Injuries May be Linked to ADHD Years Later
March 23, 2018 - Why treating addiction with medication should be carefully considered
March 23, 2018 - Researchers make key discovery about cellular pathway linked to myriad of diseases
March 23, 2018 - Researchers uncover cause of rare childhood neurodegenerative disease
March 23, 2018 - Measles infection in early childhood could contribute to later COPD
March 23, 2018 - Opioid painkiller is top prescription in 11 states
March 23, 2018 - Sienna Biopharmaceuticals Announces First Patient Dosed In Proof-of-Concept Trial of Topical By Design™ JAK Inhibitor SNA-125 for Atopic Dermatitis
March 23, 2018 - In Teen Girls, Neural Patterns May Drive Emotional Resilience
March 23, 2018 - Gene-based test for urine detects, monitors bladder cancer
March 23, 2018 - BD to introduce new digital solution for IV chemotherapy administration process at EAHP 2018
March 23, 2018 - New computational method helps to identify tumor cell mutations with greater accuracy
March 23, 2018 - Researchers identify potential obesity treatment in freezing hunger-signaling nerve
March 23, 2018 - Wales participates in the 100,000 Genomes Project
Using AFM to study cancer cells

Using AFM to study cancer cells

image_pdfDownload PDFimage_print

An interview with Prof. Hermann Schillers, Universität Münster conducted by April Cashin-Garbutt, MA (Cantab)

Can you please give a brief introduction to your research?

I run a core facility for AFM techniques, biological medical applications. My research is focussed on in the interaction of platelets and cancer cells.

Platelets support cancer cells in nearly every step of forming metastases, starting with the escape of immune surveillance, followed by the cancer cell arresting to the vessel wall and also in extravasation.

Our idea is that if we could prevent the interaction of platelets and circulating cancer cells, we may find something to block the formation of metastases, which might fight cancer.

How do you use AFM imaging and force-spectroscopy-based modes to study the structure and mechanical properties of cancer cells?

In platelet−cancer cell interaction, I use single cell force spectroscopy to quantify the interaction of platelets and cancer cells and to quantify the effect of drugs that prevent this interaction.

With this technique, we got real numbers of the forces between platelets and cancer cells for the first time. Microfluidic experiments allow to quantify the number of platelets on cancer cells, but we can’t quantify the strength of that interaction. With single cell force spectroscopy we got picoNewtons (pN) and femtoJoules (fJ). And this is necessary when you want to know which drug prevents this interaction at which concentration.

Another point is that we want to see what happens when a platelet binds to a cancer cell. The actual understanding of the situation is that platelets form a kind of ´invisible´ cloak around the circulating cancer cell, but we never observed this.

When we scan platelet cancer cell aggregates, we see that platelets on top of cancer cells vanish within 30 minutes. Using Resolve’s fastTapping mode, we could observe this uptake of platelets into cancer cells. We proved this with fluorescent techniques such as cell sorting and confocal microscopy and we clearly saw that there was an uptake but not a cloak formation.

How much is currently known about the way in which cancer cells “hijack” the services of platelets?

The widespreaded view is the cloak formation of platelets around circulating cancer cells. This layer of platelets protects the cancer cell against the immune system and, in the next step, facilitate the arrest of the cancer cell-platelet aggregate to the endothelial wall to start the extravasation.

Since we never observed this cloak formation but always observe the uptake of platelets by cancer cells, we think it is more likely that the cancer cell uses platelet proteins, platelet-specific adhesion molecules, to adhere to the vessel wall and also to escape immune surveillance.

In addition, it is known that platelets, as well as platelet-derived microparticles, contain mRNA and this changes the proteome of the cancer cell. Therefore, it could be both ways: the use of platelet proteins directly after the platelet uptake, followed by use of the platelet mRNA to produce platelet proteins to escape immune surveillance and adhere to the vessel wall.

In what way can AFM further our understanding?

We look for the first step of platelet cancer cell interaction, but there are several further steps. What I now try to do is to use PeakForce QNM to see a pattern of biomechanical changes of the cancer cell after interaction with platelets.

So far we found a kind of biomechanical footprints at the position where the cancer cell gobbles up a platelet. There is a change in elasticity and viscosity in the cancer cell membrane that may give us some hints about the mechanism by which the cancer cell incorporates the platelet. We know from experiments that this is in a dynamin-dependent process but want to know more about this.

The next step is that we want to know what change the cancer cell undergoes after uptake of platelets. We are again using single cell force spectroscopy. We incubate cancer cells with platelets and then perform single cell force spectroscopy on activated endothelium.

We are looking for the arrest of circulating cancer cells on endothelium and quantify the adhesion force. We saw that when cancer cells made contact with platelets, they became much stickier to the activated endothelium, compared to untreated cancer cells. That is one of the projects we are currently involved in.

We also look for the interaction site of these platelet-incubated cancer cells on activated endothelium. I don’t think that the platelet-incubated cancer cell could adhere everywhere on activated endothelium. There must be a specific predilection site.

We want to figure out where it adheres to. Is this cell junction or the cell body of endothelial cells or does the endothelial cell need special mechanical characteristics to form a metastatic nice with a platelet-incubated cancer cells and then proceed to extravasation?

What is the biggest impact that AFM has made to the biological and nanomedicine research fields?

We are able to look at living cells and even at subcellular structures. It is still a technique where we are limited to the surface, but when we apply a little bit force, we can see beneath the surface and observe cytoskeletal dynamics, for instance.

Twenty years ago, there were images of a couple of cells, rather blurry than resolved, and then it started to become more and more a high resolution imaging technique for living cells. However, pure imaging of cells runs out of steam after a while mechanical characterization became the focus and there is still a focus on the measurement of live cell’s elasticity, viscoelasticity and the changes in the elastic modulus. Cell dynamics is something we could follow with AFM and it includes biomechanics as well as biochemistry.And  biomechanics is as important as biochemistry.

The field of biochemistry is 30 or 40 years old, with very detailed knowledge about the biochemistry of cells, but biomechanics is rather new. In 2007, Michael Sheets and Viola Vogel published a review where they showed that mechanics influenced biochemistry and vice versa. An example: When you apply force to a protein it might open up cryptic binding sides or destroy binding sites, then the intracellular signalling pathway and the cells behaviour goes in a different direction. Today we know that biomechanics influences biochemistry and biochemistry influences biomechanics.

How has Bruker technology helped or advanced AFM in biological research?

There’s the tapping mode, which was invented by Bruker many years ago allowing to get information about the cell − curvature, cell heights, providing morphological data.

The latest great success was PeakForce QNM where we get several data sets of live cells` morphology and biomechanical parameters, such as elasticity, dissipation, adhesion and deformation in one scan process.  

And this at a rather good speed, especially on the Resolve system, which enabled us to observe dynamical changes of a layer of cells, single cells and even subcellular structures like cytoskeletal rearangements with a time resolution in the range of a minute and below. So perhaps you may not have significant changes in the topographic channel, but you did see a lot in the data channels for adhesion, dissipation or elasticity. This is a real improvement.

What is the importance of meetings, like the AFM BioMed Conference, to you and the AFM research community?

One might say that today you could use Skype, e-mail or a phone to get in contact with the people, but that’s not the same – it is completely different. When we met for the conference, we stayed here together for a couple of days.

A well-organized coffee break is the most important thing at a meeting because people come together to talk about things they don’t come up with when they are on stage giving a talk. So the time outside the lecture hall is very important, people discussing so many things and longlasting contacts start here.

Many, many cooperations start from meetings like this. No Skype conference will ever substitute a conference where people physically come together to talk, so it is absolutely necessary.

What direction do you see, or would like to see, AFM going in the next five years? (What do you see as the next big thing for AFM?)

One of the things AFM needs is speed. More speed would mean that you could follow the dynamics of cells at a better time resolution. Another point is that since AFM was invented we have used the old optical lever system and I think it is now time for a new system that moves away from one cantilever, or one indenter, to a multi-probe array AFM.

Several ideas are being discussed and micro- and nanofabrication techniques have reached a high level of development. So why should the leading providers of AFMs not try to improve AFM techniques by a more fundamental change?

Such a multi-probe array would be interesting not only in terms of speed and resolution, but also in terms of measuring biomechanical characteristics. The way we do it today is we indent the cell in this position, that position, and so on.

But we know that a cell reacts on each indentation which causes calcium spikes and cytoskeletal rearrangement; what we get in the last indentation is different from what we get in the first indentation. Therefore, multi-probe array system would be very useful for every AFM user and especially in the field of Bio-AFM application.

Another thing that was mentioned during the talks at AFM BioMed was chemical characterization. We are still in a situation where we are blind-folded when we touch our samples. We may feel something, but we can’t see what it is. There are attempts using IR and raman spectroscopy, for instance; they are at a stage where researchers try things but it’s actually difficult to handle and have several limitations. However, something like this would help in getting more information beside topographical and mechanical information.

For instance, it would be a real large improvement when we could do a scan and find out that something is stiff showing a high protein content and that the soft area could be related to lipids. Also recording the membrane potential simultaneously with topography, mechanics and chemical characterization would be a very useful improvement for all life cell research.

Where can readers find more information?

About Prof. Hermann Schillers

Prof. Dr. Hermann Schillers is Group leader at the Institute of Physiology II, University of Münster. He holds a Doctorate in Chemistry and a Habilitation from the University of Münster.

In 2003 he held a patent for a method for detecting diseases that are associated with defects of cystic fibrosis transmembrane conductance regulator (CFTR) protein.

Tagged with:

About author

Related Articles