The small and the beautiful

March 12, 2004

With the help of semiconductor nanocystals, researchers at the Max Planck Institute for Biophysical Chemistry in Goettingen, Germany, and their collaborators at the Universidad de Buenos Aires are now able to capture movies of signal transmission processes involved in the control of gene expression (Nature Biotechnology, February 2004 issue). This breakthrough is expected to speed up the development of new cancer-curing drugs. Quantum Dots (or QDs) can be used as nano-sized markers to visualize DNA sequences, proteins, or other molecules and track them in the cell. The complexes consisting of QDs and specific ligands, in this case a cellular growth factor, bind to target molecules such as receptors on the cell surface. The QDs glow in a variety of colors and are up to 1000 times brighter than conventional fluorescent dyes.

In a study published in the February issue of the acclaimed science journal Nature Biotechnology, Diane Lidke and her colleagues present results of their experiments with Quantum Dots. These are nano-sized semiconductor crystals a mere ten millionth of a millimeter in diameter that fluoresce in several different colors upon excitation with a laser source. These crystals enabled the researchers to deliver real-time video-clips of signal transmission in the so-called erbB receptor family, important targets for many anti-tumor drugs such as antibodies directed against breast cancer. Among other processes, the movies capture the uptake and subsequent redistribution of the receptor-growth factor complexes into the interior of the cell.

"The in vivo measurements reported in our study revealed new insights into cellular processes and interactions that could previously only be studied on fixed (dead) cells," wrote the researchers, led by Dr. Thomas Jovin, chairman of the Max Planck Institute for Biophysical Chemistry's Department of Molecular Biology. "An understanding of receptor-mediated transduction is essential for rational receptor-targeted cancer therapeutics. Quantitative approaches based on multiple combinations of quantum dots and ligands will be invaluable for such investigations."

In the same issue of Nature Biotechnology, two leading experts in live cell imaging reviewed the results of the study. "Semiconductor nanocrystals can track movements of individual receptors on the surface of living cells with unmatched spatial and temporal resolution", wrote Gal Gur and Yosef Yarden of Israel's Weizmann Institute of Science. "(Other) imaging methodologies have limited spatial and temporal resolution and either require complex manipulation or are able to provide only very brief snapshots of receptor dynamics."

Conventional tools, such as fluorescent dyes and polymer spheres, bleach too quickly - sometimes within seconds - to be of use for extended video images of living cells, according to the researchers. Quantum Dots, on the other hand, are not only very photostable but also very bright, making it possible to trace many elements of the cell for minutes or even hours at a time. Today, the length of observation time is a critical factor for the study of cellular processes, since rapid changes can occur over a time span of seconds or minutes.
Related links:

[1] Videos and supplementary information are freely accessible at Nature Biotechnology's web site:

Original work:

Lidke, D.S., P. Nagy, R. Heintzmann, D.J. Arndt-Jovin, J.N. Post, H. Grecco, E.A. Jares-Erijman and T.M. Jovin
Quantum dot ligands provide new insights into erbB/HER receptor-mediated signal transduction
Nature Biotechnology. 22, 198-203, February 2004


Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to