The last few years have seen considerable advancement in the field of nanotechnology as applied to medicine. This has focused on the use of nanoparticles to more accurately target sites of infection and areas of cancerous growth.
Nanoparticles range in size from about 100 nanometers down to about one nanometer (one billionth of a meter). The particles are typically the size of small molecules, and far too small to see with a microscope. Considerable investment is being placed into nanoparticles for fighting cancer. This relates to the difficulty of delivering drugs to cancerous sites; because some forms of cancer are resistant to conventional medications; and due to side-effects associated with conventional treatments. Traditional cancer treatments like radiation and chemotherapy have major side effects, because they not only affect the cancer tumors, but also the healthy parts of the body. Nanoparticles used to address cancer are sometimes referred to as submicronic colloidal systems.
In a new breakthrough, medical scientists from the University of Cincinnati College of Medicine have been developed multifunctional RNA nanoparticles that appear to overcome treatment resistance in breast cancer. When used in combination with existing treatments the technology is able to tackle the aggressive and hard to treat tumor.
The process uses a bespoke nanodelivery system to target HER2-positive breast cancer. On reaching the site, the process halts the production of protein called MED1. Suspending this protein slows down tumor growth. It also prevents cancer from spreading further. The nano-process also sensitizes the cancer cells so they become susceptible to conventional chemotherapy drugs, in this case the drug tamoxifen (which is an established medicine for estrogen-driven cancer).
HER2 (human epidermal growth factor) is a protein that can affect the growth of some cancer cells. It is found on the surface of normal breast cells. HER2-positive breast cancers tend to grow faster and are more likely to spread and come back compared to HER2-negative breast cancers. The MED1 protein is produced at abnormally high levels in breast cancer cells. MED1 co-produces and co-amplifies with HER2 in most cases (that is it extenuates the cancer formation). Importantly the interaction between HER2 and MED1 makes such cancers resistant to conventional treatment.
Clinical studies have shown that when MED1 is eliminated this halts cancer cell growth. Getting to the appropriate site to halt production is difficult and this is where nanotechnology comes in. The nanotechnology has been devised by Professor Xiaoting Zhang and it is based on RNA nanoparticles.
Speaking with Controlled Environments magazine, Professor Zhang explains further: “Most breast cancers express estrogen receptors, and the anti-estrogen drug tamoxifen has been widely used for their treatment.”
The researcher adds: “Unfortunately, up to half of all estrogen receptor-positive tumors are either unresponsive or later develop resistance to the therapy. In this study, we have developed a highly innovative design that takes advantage of the co-overexpression of HER2 and MED1 in these tumors.”
The RNA nanoparticles are capable of binding to HER2-overexpressing breast tumors. Once bound the nanoparticles can eliminate MED1 expression and this significantly decreases estrogen receptor-controlled target gene production. The nanoparticles also reduce the proportion of cancer stem cells, which further prevents tumor spread.
Due to concerns with bio-safety, the nanoparticles have first been tested out using an animal model. While further studies are required, a human trial is not too far away. This will take the form of a controlled clinical trial.
The research has been published in the journal ACS Nano. The research is called ” Overcoming Tamoxifen Resistance of Human Breast Cancer by Targeted Gene Silencing Using Multifunctional pRNA Nanoparticles.”
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we examined the detection of a new, mysterious valley on the surface of the planet Mercury. The week before we weighed in on research about a gene that could prevent people from drinking excessively.
