A sticky business -- how cancer cells become more 'gloopy' as they die

March 16, 2009

The viscosity, or 'gloopiness', of different parts of cancer cells increases dramatically when they are blasted with light-activated cancer drugs, according to new images that provide fundamental insights into how cancer cells die, published in Nature Chemistry today (15 March).

The images reveal the physical changes that occur inside cancer cells whilst they are dying as a result of Photodynamic Therapy (PDT). This cancer treatment uses light to activate a drug that creates a short-lived toxic type of oxygen, called singlet oxygen, which kills cancerous cells.

The research team behind the study says that revealing what happens to viscosity within a dying cancer cell is important because it helps give a better understanding of how cells function and which factors are important for controlling reactions inside cells. Ultimately this could help scientists design more efficient drugs for Photodynamic Therapy and other treatments.

The research is also of wider significance because these are the first ever real-time maps showing viscosity changing over a period of time inside a cell during a biologically important process like cell death.

Previous studies have shown that the viscosity of human cells and organs also changes in patients with diseases including diabetes and atherosclerosis, says lead author Dr Marina Kuimova from Imperial College London's Department of Chemistry.

She explains: "We're still not quite sure exactly what the relationship is between increased stickiness inside cells and disease, but we expect that the two are related."

"Knowing more about these changes, and being able to map them when they occur in all kinds of different scenarios, from dying cancer cells, to diseased blood cells, could help us to better understand how some diseases and their treatments affect cell and organ function."

Dr Kuimova and her colleagues were able to track viscosity as it changed inside live cancer cells thanks to a newly-developed Photodynamic Therapy drug, with unusual fluorescent properties. The drug, which is made of a molecule with a spinning component like a rotor, emits different wavelengths of light depending on the viscosity of its surroundings.

The changing wavelengths of light emitted during experiments, and captured over a period of 10 minutes, showed that once the PDT drug was activated, the level of viscosity inside the cell increased dramatically. The researchers suggest that this increasing 'gloopiness' is caused by the toxic oxygen molecules released into the cell. They think that increased levels of viscosity might even contribute directly to the cancer cell's further deterioration by slowing down vital communication and transport processes inside the cell.

Dr Stanley Botchway from the Science and Technology Facilities Council which worked in collaboration with Imperial College London on this research, said: "The huge viscosity we measured was surprising and it certainly gives a new insight into the change in cellular environment during cell death."

However, the researchers noted that as viscosity in the cancerous cell increases, the toxic oxygen molecule's mission to kill the cell is slowed down too.

Dr Kuimova explains: "It looks like whilst the increasing viscosity contributes to the cell's demise, these new 'sticky' cell conditions can slow the drug down too, so it's not as straightforward a relationship as it might first appear.

"More work is needed to better understand the complex interplay between viscosity and cell death. We hope to use our imaging technique to track changes in viscosity in other kinds of cells as they occur in real-time, to unlock some of the secrets of what goes on inside cells when they're functioning, malfunctioning or dying."

Imperial College London

---

---

	Viscosity of Liquids by Dabir S. Viswanath (Author), Tushar K. Ghosh (Author), Dasika H.L. Prasad (Author), Nidamarty V.K. Dutt (Author), Kalipatnapu Y. Rani (Author) This book is unique in that it brings together published viscosity data, experimental methods, theoretical, correlation and predictive procedures in a single volume. The - readers will get a better understanding of why various methods are used for measuring viscosity of different types of liquids and why an experimental method is dependent on fluid characteristics, such as Newtonian or non-Newtonian fluids. Undergraduate and graduate students in any science and engineering disciplines will find this book very useful. It is an excellent reference book for chemical engineers, mechanical engineers, and food engineers. Any researchers associated with chemical synthesis, process development, fluid flow, the petroleum industry, the chemical - industry or commercial enterprises will benefit...
	Food Texture and Viscosity, Second Edition: Concept and Measurement (Food Science and Technology) by Malcolm Bourne (Author) Drawing together literature from a variety of fields, Food Texture and Viscosity, 2E, includes a brief history of this area and its basic principles. It reviews how texture and viscosity are measured, including the physical interactions between the human body and food, objective methods of texture measurements, the latest advances in texture-measuring instruments, various types of liquid flow, and more. This revised edition contains approximately 30% new material, including two new chapters on physics and texture and the correlation between physical measurements and sensory assessments. It now includes two-color illustrations and includes a current list of equipment suppliers. * Completely revised with approximately 30% new...
	Controlled Markov Processes and Viscosity Solutions (Stochastic Modelling and Applied Probability) by Wendell H. Fleming (Author), Halil Mete Soner (Author) This book is an introduction to optimal stochastic control for continuous time Markov processes and the theory of viscosity solutions. It covers dynamic programming for deterministic optimal control problems, as well as to the corresponding theory of viscosity solutions. New chapters in this second edition introduce the role of stochastic optimal control in portfolio optimization and in pricing derivatives in incomplete markets and two-controller, zero-sum differential games.
	Optimal Control and Viscosity Solutions of Hamilton-Jacobi-Bellman Equations (Modern Birkhäuser Classics) by Martino Bardi (Author), Italo Capuzzo-Dolcetta (Author) This softcover book is a self-contained account of the theory of viscosity solutions for first-order partial differential equations of Hamilton–Jacobi type and its interplay with Bellman’s dynamic programming approach to optimal control and differential games. It will be of interest to scientists involved in the theory of optimal control of deterministic linear and nonlinear systems. The work may be used by graduate students and researchers in control theory both as an introductory textbook and as an up-to-date reference book.
	Blood microrheology: viscosity factors in blood flow, ischaemia, and thrombosis;: An introduction to molecular and clinical haemorheology by Leopold Dintenfass (Author)
	Viscosity Solutions and Applications: Lectures given at the 2nd Session of the Centro Internazionale Matematico Estivo (C.I.M.E.) held in Montecatini ... Mathematics / C.I.M.E. Foundation Subseries) by Martino Bardi (Author), Michael G. Crandall (Author), Lawrence C. Evans (Author), Halil M. Soner (Author), Panagiotis E. Souganidis (Author), Italo Capuzzo Dolcetta (Editor), Pierre Lions (Editor) The volume comprises five extended surveys on the recent theory of viscosity solutions of fully nonlinear partial differential equations, and some of its most relevant applications to optimal control theory for deterministic and stochastic systems, front propagation, geometric motions and mathematical finance. The volume forms a state-of-the-art reference on the subject of viscosity solutions, and the authors are among the most prominent specialists. Potential readers are researchers in nonlinear PDE's, systems theory, stochastic processes.
	Recent Progress on Reaction-Diffusion Systems and Viscosity Solutions by Yihong Du (Editor), Hitoshi Ishii (Editor), Wei-Yueh Lin (Editor) This book consists of survey and research articles expanding on the theme of the 'International Conference on Reaction-Diffusion Systems and Viscosity Solutions', held at Providence University, Taiwan, during January 3-6, 2007. It is a carefully selected collection of articles representing the recent progress of some important areas of nonlinear partial differential equations. The book is aimed for researchers and postgraduate students who want to learn about or follow some of the current research topics in nonlinear partial differential equations.The contributors consist of international experts and some participants of the conference, including Nils Ackermann (Mexico), Chao-Nien Chen (Taiwan), Yihong Du (Australia), Alberto Farina (France), Hitoshi Ishii (Waseda), N Ishimura (Japan),...
	Transport Properties of Chemicals and Hydrocarbons: Viscosity, Thermal Conductivity, and Diffusivity for more than 7800 Hydrocarbons and Chemicals, ... C1 to C100 Organics and Ac to Zr Inorganics by Carl L. Yaws (Author) Carl Yaws, a leading authority on chemical compounds in the chemical engineering field, has done it again. In Transport Properties of Chemicals and Hydrocarbons -- an essential volume for any chemist or chemical engineer's library -- he has amassed over 7,800 organic and inorganic chemicals, and hydrocarbons. Spanning gases, liquids and solids, and covering all critical properties (including viscosity, thermal conductivity, and diffusion coefficient), this volume represents more properties on more chemicals than any single work of its kind. From C1 to C100 organics and Ac to Zr inorganics, the data in this handbook was designed and formatted for field, lab or classroom usage. By collecting a massive amount of information in one source, this handbook will simplify your research and...
	The Mathematical Theory of Non-uniform Gases: An Account of the Kinetic Theory of Viscosity, Thermal Conduction and Diffusion in Gases (Cambridge Mathematical Library) by Sydney Chapman (Author), T. G. Cowling (Author), C. Cercignani (Foreword) This classic book, now reissued in paperback, presents a detailed account of the mathematical theory of viscosity, thermal conduction, and diffusion in non-uniform gases based on the solution of the Maxwell-Boltzmann equations. The theory of Chapman and Enskog, describing work on dense gases, quantum theory of collisions, and the theory of conduction and diffusion in ionized gases in the presence of electric and magnetic fields is also included in the later chapters. This reprint of the third edition, first published in 1970, includes revisions that take account of extensions of the theory to fresh molecular models and of new methods used in discussing dense gases and plasmas.
	Psychedelic White: Goa Trance and the Viscosity of Race by Arun Saldanha (Author) "Psychedelic White is one of the most innovative, refreshingly different analyses of race I have read in the last decade." —Elizabeth Grosz, author of The Nick of Time: Politics, Evolution and the Untimely The village of Anjuna, located in the coastal Indian state of Goa, has been one of the premier destinations on the global rave scene for nearly two decades. The birthplace of Goa trance, the most psychedelic variety of electronic dance music, Anjuna first attracted adventurous Westerners in the 1970s who were drawn there by its tropical beaches, tolerant locals, and readily available drugs. Today, rave tourists travel to Goa to take part in round-the-clock dance parties and lose themselves in the crowds, the music, and the drugs. But do they really escape where they come from...