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Learn how scientists are fighting cancer... with algae!

Hosted by: Michael Aranda
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Sources:
http://www.nature.com/ncomms/2015/151110/ncomms9791/full/ncomms9791.html
http://www.ibtimes.co.uk/algae-genetically-engineered-kill-90-cancer-cells-without-harming-healthy-ones-1528038
http://www.livestrong.com/article/123423-chemotherapy-drugs-kill-cancer-cells/
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072611/
http://www.kinderkrebsinfo.de/patients/therapy/methods_of_treatment/pohkinderkrebsinfochemotherapie/cytostatic_agents/mode_of_action/index_eng.html
http://www.oscarfish.com/article-home/water/82-diatoms.html
http://book.bionumbers.org/how-quickly-do-different-cells-in-the-body-replace-themselves/
For the past week, a new cancer treatment method has been making headlines, with titles like “Genetically engineered algae kills 90% of cancer cells, leaving healthy cells alone.” Which... kind of makes it sound like we’ve suddenly cured cancer. And a team of researchers has engineered a new type of algae that helps fight cancer. But this algae isn’t what’s actually killing the cancer -- instead, it’s being used as a delivery mechanism for the chemotherapy drugs we already have.

It’s pretty exciting -- but not because of the ‘kills 90% of cancer cells’ part. The chemotherapy drugs already did that, for the type of cancer the researchers were studying. But the ‘leaves healthy cells alone’ part? That is a big, big deal. To understand how this algae could potentially change the lives of cancer patients, we first have to talk about what cancer is, and how chemotherapy drugs try to fight it.

Nearly all of the cells in your body divide -- and they’re supposed to. They mature, reproduce, die, and are replaced by a younger generation of cells. Some cells, like the cells that make up the tissue inside your mouth, get replaced almost every week. Those cells are constantly awash in digestive enzymes, along with whatever weird stuff you’re eating, so they endure a lot of wear and tear, and they need to be replaced frequently. Other cells live for years -- like your fat cells, which don’t have to do a whole lot except sit there. Each type of cell is supposed to follow its particular internal clock, which is encoded in its DNA.

But in cancer cells, that clock is broken. That part of its DNA has been damaged, and instead of waiting a week, a few months, or several years to reproduce, it does it NOW. It just keeps dividing, out of control, spreading into and destroying any nearby tissue. So the goal of chemotherapy drugs is to interrupt the process of cell division -- since cancerous cells are dividing all the time, they’re mostly the ones that get hit.

Chemotherapy usually involves taking a lot of different kinds of these drugs, to block ANY attempts those cancerous might make to divide. And often it does work. But it comes with a lot of side effects, because it doesn’t just block cancer cells from dividing -- it blocks ALL of your cells from dividing. Meaning that as non-cancerous cells naturally age and die, new cells aren’t available to take their place. Many of the awful side-effects of chemotherapy are a result of this breakdown in cell division. Weakness and fatigue come from a breakdown in the production of new red blood cells, which have a renewal rate of about four months. Nausea and painful or difficult stools come from a breakdown in cell division in your stomach lining and intestines, where cells are typically replaced every week. And people going through chemotherapy have compromised immune systems because the white blood cells that are so important for fighting infections are meant to be produced as often as every three days.

If you’ve ever known anybody going through chemotherapy, or have gone through it yourself, you know it’s a really hard process. And that is where this new algae treatment comes in. Instead of injecting the chemotherapy drugs into a patient’s bloodstream so they circulate EVERYWHERE, the drugs are attached to the algae, which has been genetically engineered to only bond with cancer cells. In a study published last week in the journal Nature Communications, this was tested by a group of biologists and chemists who engineered the algae to be covered in the antibodies for that patient’s particular cancer cells.

You can think of all the cells in your body as being covered in locks, called receptors, and the antibodies are like the keys. So the algae cells, which are only 20 nanometers across -- about 5000 times smaller than the width of a human hair -- bounce around between your cells harmlessly, until they bump into a cancer cell, where they lock on. The chemotherapy drugs can then pass through the membrane of the cancer cell where the algae is bonded to it. The drugs do their work on the cancer, without ever coming into contact with the healthy cells in your body.

And it’s not like this is some newly discovered exotic algae uncovered from under a melting ice cap or something. If you’ve ever had a fish tank, you’ve probably seen this stuff before. You know that brown crusty stuff that forms on everything if the fish tank isn’t kept clean? That brown crusty stuff is called biomineralized silica, and it’s what makes diatoms - this abundant, single-celled algae - such an incredible vehicle for medicine.

Diatoms take silicon and use it to form a natural porous shell around themselves. And those little balls of biosilica can carry the chemotherapy drugs straight to their target. When they were testing the delivery system, the researchers induced tumors in mice, then injected them with this engineered biosilica. Just five days after treatment, the tumors had shrunk by half. The team then injected the biosilica into healthy mice, and examined them for any signs of tissue damage. And... they didn’t find any.

This isn’t a totally new idea -- tiny particles of porous silica are already being used as an experimental delivery system for drugs. But until now, those particles could only be manufactured artificially, and it was a slow, expensive process that involved a lot of really toxic chemicals. But this algae, it just...grows. Which means, pending more testing, that this could be a new way to administer chemotherapy that’s affordable, safe, and doesn’t come with as many side-effects. And THAT is exciting news.
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