Day: August 6, 2021

Categories : CancerTags :

Powering Up NK Cells With Magnetism

On By ModernMedia
NK cells attack a cancer cell (centre). Source: NIH

Powering up natural killer cells with magnetic nanoparticles could enhance cancer immunotherapy, according to a Northwestern Medicine study published in ACS Nano.

This method could allow for the unleashing of natural killer (NK) cells on a variety of solid tumours, according to senior author Dong-Hyun Kim, PhD, associate professor at Northwestern.

“People have had trouble applying NK cells to solid tumours,” said Prof Kim. “If we can provide an easy path to modulate NK cells, perhaps this can become a useful therapy.”

Most cell-based immunotherapies involve T-cells, but these chimeric antigen receptor (CAR) T-cell therapies are costly and have a long incubation period and strong side effects.

On the other hand, NK cells belong to the innate immune system and are quicker to respond to pathogens. NK cell immunotherapy has been explored, according to Prof Kim, but that too has barriers.

“It’s pretty hard for these cells to penetrate inside the tumours which have thick barrier tissues,” Prof Kim said.

Magnetically activated NK cells
Boosting NK cell function with cytokines have proven unsuccessful and, like CAR T-cell therapy, have a high cost and lengthy manufacturing time. However, Prof Kim’s previous work with nanoparticles inspired a different approach.

Prof Kim and colleagues developed a magnetic nanocomplex that binds with NK cells and, when activated with an alternating magnetic field, exerts force on the exterior of the cell, promoting secretion of cytotoxic compounds. Testing this nanocomplex in animal models of hepatocellular carcinoma, the investigators found that magnetic activation increased the cancer-killing ability of NK cells when injected into solid tumours.

As a bonus, these nanoparticles show up with MRI, allowing for precise monitoring of NK cell distribution during and after injection.

“This creates a stronger NK cell, and can hopefully enhance the efficacy of the treatment,” Prof Kim said.

Source: Northwestern University

Categories : New Compounds and TreatmentsTags :

New Molecules Provide Deeper UV Protection

On By ModernMedia
Photo by rfstudio on Pexels

Two new molecules that release tiny quantities of hydrogen sulfide have been found to prevent skin from ageing after being exposed to ultraviolet light found in sunlight. The study was published in Antioxidant and Redox Signalling.

For the study, the researchers exposed adult human skin cells and the skin of mice to ultraviolet radiation (UVA). UVA causes skin ageing by turning on collagenases, enzymes which eat away at the natural collagen, causing the skin to lose elasticity, sag and wrinkle. UVA also penetrates deeper into skin than the UV radiation that causes sunburns (UVB), and it also damages cellular DNA, leading to mutations that can contribute to some skin cancers. Typical sun creams sit on top of the skin and absorb UV radiation, but they do not penetrate the skin where the long-lasting damage occurs.

For deeper protection, the researchers came up with a new way to protect the deeper layers of skin using two compounds invented at the University of Exeter: AP39 and AP123. The compounds do not protect the skin in the same way traditional sun creams prevent sunburn, but instead penetrate the skin to correct how skin cells’ energy production and usage was turned off by UVA exposure. This then prevented the activation of skin-degrading collagenase enzymes. 

The compounds used in this study were previously shown to have impressive effects in reducing skin inflammation and skin damage after burn injury and atopic dermatitis (eczema). In an anti-ageing context, they prevented human skin cells in test tube experiments from ageing, but this is the first time the effects of photo-ageing have been seen in animals.

The important observation noted was that the compounds only regulated energy production, PGC-1α and Nrf2 in skin that was exposed to UVA. This suggests a novel approach to treating skin that has already been damaged by UV radiation, and could potentially reverse, as well as limit, that damage.

While further research is needed, there could be medical as well as cosmetic implications from this work, where protecting skin from UV light is important. For example, not only premature skin ageing and skin cancers, but UV light allergies, solar urticaria and rare hereditary skin diseases such as xeroderma pigmentosum. The researchers are currently partway through testing newer and more potent molecules able to do the same task using newer approaches.

Source: University of Exeter

Categories : Diseases, Syndromes and ConditionsTags :

Host Genes Can Hinder H. Pylori Eradication

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Helicobacter pylori is a strong risk factor for gastric cancer and other gastrointestinal disorders, and efforts to eradicate it using a combination of antibiotics and proton pump inhibitors (PPIs) often fail.

A new study has linked this eradication failure with genetic variations that increase the activity of the CYP2C19 enzyme, which metabolises first-generation PPIs.

These so-called ‘fast metabolisers’ may prevent PPIs from suppressing gastric acid production, which is necessary for successful H. pylori eradication.

Analysing 57 studies from 11 countries, the researchers found that the failure rate of H. pylori eradication more than doubled in people with a version of the CYP2C19 gene that increased its metabolic activity. Their results were published in Gastroenterology.

However, CYP2C19 variants were not linked to eradication failure if the fast metabolisers were treated with newer PPIs such as esomeprazole and rabeprazole, which are less metabolised by the enzyme or which bypass CYP2C19 metabolism.

Further well-designed studies are needed to determine whether eradication rates could be improved with higher or more frequent dosages of first-generation PPIs to people with the fast metaboliser gene variant, noted the paper’s corresponding author, Shailja Shah, MD, MPH.
“Even small improvements in H. pylori eradication rates would likely translate to substantial collateral health, economic and societal benefits,” the researchers concluded.

Source: Vanderbilt University