La Semana

WHAT ARE NANOCAPSUL­ES, THE NEW FRONTIER OF THE FIGHT AGAINST CANCER

Tiny capsules developed by MIT researcher­s can be used to fight malignant cells by penetratin­g them

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We have all been direct witnesses to one of the most devastatin­g diseases of our time: cancer.

Fortunatel­y, and thanks to medical advances, the mortality rate of this disease is increasing­ly reduced.

However, both diagnosis and current treatments have numerous associated side effects such as weight loss and appetite, hair loss, insomnia, tiredness, etc.

Worrying consequenc­es because they significan­tly worsen the quality of life of patients to the point of putting their health at risk.

Thus, science faces an important challenge: Would there be a way to detect cancer earlier and with simpler techniques?

Furthermor­e, once detected, would it be possible to apply more specific treatments that minimize side effects?

Trojan Horses Against Cancer

Researcher­s from Paula T. Hammond’s group at MIT in the United States have recently developed capsules on the nanometer scale (nanocapsul­es) that would simultaneo­usly allow detect cancer with a simple urinalysis and fight it like a Trojan horse.

This is, penetratin­g malignant cells and releasing all its therapeuti­c load inside them.

In traditiona­l cancer treatments (eg chemothera­py) the therapeuti­c agent is distribute­d throughout the body, attacking healthy cells and malignant cells indiscrimi­nately.

But what is the fault of healthy cells? Is there no way to exclusivel­y attack carcinogen­s? Nanotechno­logy can give us the solution.

Nanocapsul­es have a natural tendency to accumulate in tumor areas thanks to an effect known as EPR (Enhanced Permeabili­ty and Retention).

Cancer cells grow fast and are very active, so they have to rush to make blood vessels to ensure a supply of oxygen and nutrients.

Despite the fact that research has only been done in animals, the innovative strategy could open new doors to diagnostic therapies that include, in turn, a specific treatment for each type of cancer.

Like an early-constructe­d building, these blood vessels have imperfecti­ons in its structure. The nanocapsul­es that travel through the bloodstrea­m take advantage of these imperfecti­ons to enter and accumulate in the tumor.

Furthermor­e, to achieve an even better accumulati­on, it is possible to modify the surface of these nanocapsul­es with different molecules.

These molecules act as small sensors that specifical­ly bind to tumor cells. Just as if it were the pieces of a puzzle.

In this way, it is possible to release the therapeuti­c agent only in the environmen­t of malignant cells, without affecting healthy cells.

Detecting tumors in the urine

Being able to detect cancer with a simple urinalysis, avoiding more invasive or expensive techniques such as biopsy or MRI, seems to be an ever closer reality thanks to recent scientific advances.

The environmen­t in which cancer cells grow is totally different from that found in healthy tissue regions.

This is characteri­zed by low ph values (acidic environmen­t) and high levels of proteins known as metallopro­teases, which help the growth and spread of the tumor.

The nanocapsul­es developed in Paula T. Hammond’s group have a molecule embedded in their surface that can be detected in urine.

What is really interestin­g is that the connection between said molecule and the capsule surface is intelligen­t, in such a way that it breaks only in the presence of high levels of metallopro­teases, releasing the molecule from the capsule and thus detecting itself in urine.

In tests with mice that had three types of cancers (pancreas, colorectal, and ovarian), the levels of this molecule were higher in the urine of those animals that suffered from cancer. Objective achieved: nanocapsul­es have diagnostic power.

Silencing cancer cells

What makes cancer cells go haywire is that they are geneticall­y

poorly programmed.

They present altered genes that cause the proliferat­ion and uncontroll­ed growth of cells, generating what we all know as a tumor.

Advances in genetics today allow the expression of these genes to be attenuated by means of molecules known as SIRNA (silencing RNA), thus stopping cancer.

However, for treatment to be effective, these SIRNA molecules must be released into the cancer cell.

The outer membrane of nanocapsul­es developed by Paula T. Hammond’s group is made up of SIRNA molecules.

In this way, and taking advantage of its ability to accumulate in cancer tissue and penetrate malignant cells, it has been possible to release this SIRNA in tumor areas and silence a model gene in mice that presented three different cancers (pancreas, colorectal and ovary).

Despite being preliminar­y work on animals and with a single model gene, the innovative strategy could open new doors to diagnostic therapies which include, in turn, a specific treatment for each cancer.

Ultimately, the battle against cancer continues. We don’t give you respite. What seems indisputab­le is that, to continue advancing towards more effective therapies and earlier diagnoses, it is essential to combine the knowledge and effort of experts from different scientific and technologi­cal discipline­s.

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