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Collaborators in The Netherlands have created a 3D well system integrated into biomaterials that can be used either in vitro or in vivo for molecule screening in this HOT Technical Innovation.

The research was led by Gustavo Higuera and Jeanine Hendriks at Screvo Ltd and CellCoTec, with a team at The University of Twente. Avoiding animal experimentation by using 3D systems that mimic the in vivo environment is desirable yet challenging. Optimising animal experiments to be as efficient and effective as possible is a common goal of much research.

This team envisioned the integration of such in vitro 3D cell culture mimicking methods with biocompatible materials into animal models. To do this, they create a 9-well system that can be implanted into four sites under the skin of one mouse for in vivo screening. This enables testing of up to thirty six different conditions at once.

The innovative platform was produced from a wide range of biomaterials chosen for biocompatibility instead of conventional materials like PDMS. The cell culture compatibility of wells made with copolymer PEOT-PBT was tested using human mesenchymal stem cells. They test the systemic effect of the device on surrounding tissue of twenty mice.

This innovative bridge between in vivo and in vitro experimentation has great potential to both increase throughput and minimise animal experimentation by reducing the number of animals needed. Read the article in full now as it’s free to access for the next 4 weeks*:

In vivo screening of extracellular matrix components produced under multiple experimental conditions implanted in one animal
Gustavo A. Higuera, Jeanine A. A. Hendriks, Joost van Dalum, Ling Wu, Roka Schotel, Liliana Moreira-Teixeira, Mirella van den Doel, Jeroen C. H. Leijten, Jens Riesle, Marcel Karperien, Clemens A. van Blitterswijk and Lorenzo Moroni 
DOI: 10.1039/C3IB40023A

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Today’s HOT article as recommended by the referees is from Rafael Davalos and colleagues at Virginia Tech, USA. Using contactless dielectrophoresis, the changes in the electrical properties and surface roughness of cancer cells treated with non-toxic doses of spingolipid  metabolites.

One metabolite, S1P, promotes tumour formation and the second, So, has anti-tumour properties. The electrical properties of cancer cells change as they transform from benign to malignant. Contactless electrophoresis means that there is no contact between the cells and the electrodes, ruling out challenges of traditional techniques.

Using this technique, the researchers show that treatment with So partially transforms late stage malignant mouse ovarian surface epithelial cancer cells back to a benign state. S1P as expected does not reverse the transformation.

The exploration of potential non-toxic treatments as an alternative to highly toxic chemotherapy and of drugs whose action is not affected by the presence of variable biomarkers is important. This study shows that So has the potential for such therapy and it also demonstrates contactless dielectrophoresis as a useful tool in drug efficacy studies.

As a HOT article, we’ve made it free to access for the next 4 weeks!

Sphingolipid metabolites modulate dielectric characteristics of cells in a mouse ovarian cancer progression model
Alireza Salmanzadeh, Elizabeth S. Elvington, Paul C. Roberts, Eva M. Schmelz and Rafael V. Davalos
DOI: 10.1039/C3IB00008G

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A cross-departmental team at the University of Wisconsin-Madison led by Elaine Alarid and Integrative Biology Associate Editor David Beebe use a tumour biomarker to study the surrounding microenvironment by applying microfluidics and immunofluorescence techniques in this iBiology article. Using this innovative method, they can predict how the microenvironment will influence the growth of the tumour.

The biomarker used is Estrogen Receptor-α (ERα), which is a therapeutic target in the most common form of breast cancer. There are a number of different factors involved in the ERα signalling pathway; in this article these processes are defined as the microenvironment activity.

The researchers use an array of different microenvironments in a high-throughput microfluidic co-culture model to test the different variables. Quantitative immunofluorescence imaging is used to monitor ERα levels.  Other measures used are gene expression and phosphorylation status.

They discover a previously unrecognised linear correlation between growth of the tumour and decreases in ERα protein levels, indicating activation, under most of the various signalling input conditions. This work enables ERα regulation to be a dynamic biosensor of microenvironment activity for predicting tumour growth. Two of the conditions analysed showed a different correlation with tumour growth, with the growth appearing to be independent of ERα. The group will be looking into this further as it may have implications for the effectiveness of therapy.

They envision co-culturing samples of patient tumour microenvironment with MCF-7 cells acting as a biomarker for ERα activation. Read on for more detail into the assay and the results:

Hormonally responsive breast cancer cells in a microfluidic co-culture model as a sensor of microenvironmental activity
Jessica D. Lang, Scott M. Berry, Ginny L. Powers, David J. Beebe and Elaine T. Alarid
DOI: 10.1039/C3IB20265H

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A team at Stanford University, USA, test how changing the stiffness of the body changes sensitivity of touch of the model worm C. elegans using a microelectomechanical clamp.

Touch is the least understood of the five human senses. It is obvious that force applied to the skin is an important stimulator of neurons and mechanoreceptors below the surface. The mechanics of this process are not understood. In this HOT article, the researchers test the hypothesis that body stiffness influences touch sensitivity.

The microelectromechaical (MEMS) force clamp applies a force to a freely crawling worm and the team then measured the response stimulated by the level of force. The clamp is integrated with a moving stage. The worms are sensitive to under 1 μN of force and to indentations under 1 μm deep.

The team led by Miriam Goodman and Beth Pruitt then genetically alter the wild type worms’ skin proteins, softening the skin. They also modify their ability to control body wall muscles to show the effects of changing body mechanics.  Even small changes resulted in dramatic changes in force sensitivity, but had little effect on indentation depth sensitivity. They looked into whether the worms were directly responding to the force or whether they were reacting to the production of indentations. The conclusion is that the indentation of the skin drives touch sensitivity.

In this HOT article, the researchers also use a theoretical model to understand different kinds of deformation and force transfer involved. The article also discusses how this research relates to other animals and humans.

We’ve made this HOT article free to access for the next 4 weeks*:

MEMS-based force-clamp analysis of the role of body stiffness in C. elegans touch sensation
Bryan C. Petzold, Sung-Jin Park, Eileen A. Mazzochette, Miriam B. Goodman and Beth L. Pruitt
DOI: 10.1039/C3IB20293C

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A team of researchers at the University of South Carolina are investigating how cancer cells respond to the conditions of 3D cell culture and how we can use their behaviour to study anti-cancer drugs and cancer stem cells. In their work they combine biology with mathematics and biomaterials chemistry.

In this just published Integrative Biology paper, the team led by Hexin Chen and Qian Wang, culture MCF-7 cells on 3D polycaprolactone (PCL) fibrous scaffolds. The fibers are randomly orientated as in a cancerous environment collagen fibres surround breast cancer cells randomly. The fibrous scaffolds are made by electrospinning.

They discover that the epithelial-to-mesenchymal transition of the cells, required for cancer cell migration and malignancy, is enhanced when human epithelial breast cancer cells are cultured on this 3D fibrous substrate. For 2D cultures, the population of cancer stem cells remains constant.

Elucidating the exact mechanism of how will be part of the group’s further research. The researchers will also be expanding their previous mathematical models of cancer stem cell growth in tumours to include transformation of non-stem cells to stem cells. This would give an insight into whether the increase in cancer stem cells is down to non-stem cells converting or increasing division of those cancer stem cells already present.

Expansion of breast cancer stem cells with fibrous scaffolds
Sheng Feng, Xinrui Duan, Pang-Kuo Lo, Shou Liu, Xinfeng Liu, Hexin Chen and Qian Wang
DOI: 10.1039/C3IB20255K