What’s been going on?

It’s been a while since I’ve been able to blog.  I have lots of reasons, but one of the big ones is that I’ve been writing and editing for some other sites!

In mid-January, I wrote an article for the ISBER News Blog (ISBER stands for the International Society for Biological and Environmental Repositories – the premiere biobanking society in the world). The article entitled “Have you joined the ISBER social network? Facebook!” is all about how to get started on Facebook and how to get more involved with ISBER through that social media outlet.  If you aren’t on Facebook already, you may find the first half of the article useful.  Once you join, you can follow the “Things I Tell My Mom” Facebook page where I post often about interesting science I find around the web.

From this experience, I was named the new Assistant Editor for the ISBER News Blog. This was announced in a very funny article from the current editor Rick Michels called “Bringing in Backup.” I’m super excited about this new role and have jumped right in to help edit lots of interesting articles from the biobanking world.  I hope many of them will be interesting to the public, and I’ll be sure to share them either through this blog or on my Facebook page.

As part of my job, I endeavor to educate the public on the importance of biobanking in enabling cancer research. To both work towards this goal as well as to talk about the Biobank’s support of World Cancer Day, I wrote an article for the Barrow Neurological Institute blog about what our Biobank does to help cancer research. You can find that article here.

And because that’s not nearly enough, my first article for GotScience.org was published today. GotScience is a fabulous website with the goal of increasing the public awareness about science – a perfect fit for my goals and dreams! I adapted an article that I first published on this blog for GotScience about “What is a biobank?” (I think you can see a theme emerging). Please check it out along with the other articles on GotScience!

Finally, I’ve been helping out an editor friend of mine at PN Online – a magazine to help people who are wheelchair bound. I contributed to an article about this great new ALS research called “Early ALS Treatment.” I adapted my work for this article to a journal club blog post that you can read here.

I promise I’ll be back to writing on this blog soon, but until then, enjoy the articles I shared above!!

Growing tumors outside the body to kill the tumor still inside

To understand how to kill a tumor, you have to study the tumor. Historically, much of how scientists understand tumors comes from removing a tumor from a patient’s body, putting Cell_Cultureit in a plastic dish (called a petri dish), and studying whatever cells are grown in this dish. You may be familiar with the book “The Immortal Life of Henrietta Lacks” by Rebecca Skloot. This book talks about HeLa cells, which are cells that were taken from Henrietta’s cervical cancer, grown in a dish, and propagated for the past 60+ years as what is called a “cell line“.  These cells grow and divide indefinitely, and have been propagated and transferred from lab to lab to be studied.  HeLa cells are one of the most famous and most-researched cells that have helped scientists better understand cancer. HeLa cells are not the only cell line that exists or has been used to study cancer.  There are cell lines from lung cancer tumors, prostate cancer, brain cancer, and most other major cancers. However, there are a few problem with using cell lines to understand and treat cancer.

  1. Cell lines are EXTREMELY hard to create.  As you may imagine, a plastic dish is nothing like the environment inside the body that the tumor was removed from.  In the petri dish the cells are put into “media,”t he liquid that is used to feed the cells in the petri dish, and this media is also nothing like the nutrients and other growth factors feeding the tumor inside the body. Because of this unnatural environment, some of the tumor cells die – and in many cases mostor all of the tumor cells die.
  2. The cells that are left in the petri dish do not accurately represent the tumor anymore. A tumor isn’t a whole bunch of identical cells, but rather a tumor contains a lot of genetically different cells.  Scientists call this tumor heterogeneity. This is one of the reasons why drug resistant cells emerge after treating a tumor with drugs (like in the case of melanomadescribed in a previous post).  There are already drug resistant cells inside the tumor that don’t die when treated with drug.  Unfortunately, not all of these different cells in the tumor will live in a petri dish, so only a selected type or types of cells will live and can be studied.
  3. Even though cell lines had been the most useful tool in the past to understand cancer biology, they are not at all useful in understanding the EXACT tumor from a particular person. What does this mean? For example, drugs that kill HeLa cells in a petri dish might not work to kill another person’s cervical cancer because the genetic cause of that cervical cancer is different. In personalized medicine, the goal is to identify the drugs that will work to kill a particular patient’s tumor. Because of this, cell lines just aren’t good enough.

Scientists have been working on a number of solutions, and I’ll talk about four:

  1. Biobanking. A biobank collects excess tumor tissue from patients who are having a
    liquidnitrogenfreezers

    Where tumor tissue is stored in a biobank before researchers use it

    tumor removed as part of a surgery.  This tissue is immediately preserved by freezing and can then be used by researchers to study that particular tumor or many tumors of a particular type (e.g., lung cancer).  The disadvantage to this is that the tumor sample isn’t an unlimited resource. Once the tissue has been used up – it’s gone. The remaining examples all focus on growing the tumor tissue so that it can be propagated and used for many experiments.

  2. Modified cell line growth. HeLa cells were not grown in any special way, but researchers at Georgetown Universityhave found ways to grow tumor cells in a petri dish  that are identical to the tumor and nearly all tumors can grow under these conditions. So what are these conditions?  The researchers grow cells on top of a layer of mouse cells called feeder cells because they provide the cell-based nutrients to “feed” the tumor and allow it to grow.  They also use a particular inhibitor that allows the cells to grow indefinitely. They have created these modified cell lines from different types of tumors, from frozen biobanked tumors, and from as few as 4 live cells.  Even though this system, is better, it still doesn’t replicate the 3D architecture of a tumor…
  3. cancer organoids

    Cancer organoids. Notice the 3D clumps of cells after 217 days of growth. Thanks to the Kuo lab for the image

    Organoids. As you would expect the word to mean, an organoid is a mini 3D organ bud grown in a dish. Don’t imagine a teeny tiny beating heart.  These organoids are just clumps of cells, but an organized clump of cells that can help better understand cells and organs. The discovery of how to create organoids was so interesting that it was a 2013 Big Advance of the Year by The Scientists magazine. Scientist have also found a way to grow cancer cells into these 3D organoid structures. With tumor organoids, researchers can both study the genetics of the tumor (like you can with cell lines) as well as how the tumor behaved in a 3D environment that is more similar to what the tumor encounters in the body.  But what if we could do even better?

  4. Patient-derived xenograftsare when tumor tissue is taken directly from a patient’s tumor and put directly into a mouse.  Why would this be so awesome? The environment inside a mouse is more similar to the environment that the tumor is used to inside a person’s body.  The cells are less likely to die because they aren’t living in unnatural plastic. Also, a whole piece of tumor can be implanted into the mouse, maintaining the tumor cells connections to neighboring cells, which are critical for the tumor cells to communicate with one another for survival.

With all of these systems available to study tumors from a specific patient, what are scientists actually doing with these cells? In some cases, they are being used to sequence the genomes of the tumors to identify mutations that may be causing the tumor. If a tumor can be grown so that there is a lot of it, the tumor cells themselves can also be used to test treatments either in a dish or inside of a mouse. Imagine a cancer patient getting their tumor removed, part of the tumor is grown in one of the ways described above. Then the tumor is exposed to the top 10, or 50 or 100 anti-tumor drugs or combination of drugs to see what kills the tumor. This drug or combo of drugs can then be used to treat the patient. There are companies that are currently working on doing exactly this (check out Champions Oncology) so this “big dream” may soon become a cancer patient’s more promising reality.

 

Did your steak sit on the counter overnight? What experiments I did at work last week

I was at a party last night telling my non-scientist friends about my week at work.  For the first time since I left my post-doc 8 years ago, I spent multiple days in the lab doing experiments!! We had a few drinks at this point, and in their lapse of judgement (thinking I may not give them a descriptive answer at a party) they asked me what my experiments were about.  I did not disappoint, and told them all about my experiments.

This party was a BBQ and even though I’m a vegetarian, most of my friends are huge fans of meat.  So I started by asking them about steak.  If you bought a steak that you weren’t going to throw on the grill right away, you might freeze it and cook it later.  When you take it out of the freezer, how do you know if the steak is still of high quality?  Maybe it sat on the counter overnight before being put in the freezer.  Maybe the freezer lost power during a storm, the steak defrosted and when the power came back on, the steak froze again.  Maybe the steak wasn’t even good when it got to your house – maybe it sat on the butcher’s counter for a few days, forgotten about, before being put into the display case for you to buy. It may be nearly impossible to tell by just looking at your frozen steak if any of these events happened and whether or not these events would affect the steak’s quality.

frozen tissue

Steak image courtesy of Steven Depolo under a Creative Commons License

This is something that we deal with daily as biobankers. To remind you, we collect human tumor samples for researchers to use to better understand diseases and to develop improved treatments. Ideally these tissue samples are very quickly frozen (as described in this blog post) and kept frozen.  Like the steak, there are a lot of “variables” that may affect the quality of the tumor tissue sample – including the same issues that a steak may have – like sitting at room temperature for too long or freezing and then thawing and then freezing again. And also similar to the steak, it’s nearly impossible to tell by just looking at the tissue sample if any of these things have happened. Except, instead of affecting whether or not your dinner tastes good, with tumor tissue samples, research results that are essential for drug or biomarker development for brain tumors are affected.

How do we handle this little problem?  We have to use a proxy for quality – something that we can analyze directly that will tell us whether or not the tissue sample is of good enough quality to be used for certain research purposes.  In this case, the proxy is RNA.  RNA is a great molecule to look at because it’s found in every cell, but it’s also unstable because of its natural enemy RNases. When these RNases are active (when the tissue sample is warm or at room temperature) they will function like little PacMans to chomp on the RNA, turning it into smaller and smaller pieces. When frozen, the RNases are inactive and can’t chomp on RNA.  So if you look at how chomped up/small the RNA is in tissue samples, you can figure out whether the quality of the sample is good for your experiments.

rneasy column

A tiny filter (seen as the white line inside the pink tube) binds to the RNA.

This is what I did last week in the lab. How did I do this? First, I had to get the RNA out of the tissue sample. To do this, you have to separate the cells from one another, which essentially like grinding up a steak in a meat grinder. You then have to bust open the cells to get to the RNA.  You do that by adding something that works a lot like soap that opens up the outer coating of the cells.  From there, you can isolate the RNA by adding ethanol (an alcohol) that makes the RNA no longer dissolved in the liquid (what we call “precipitating” the RNA).  From there we isolate the RNA on a column – exactly like the pink one you see on the right. The white line inside the pink tube is like an RNA filter that traps RNA while letting all the other cell bits flow through. Then you use water to get the RNA out of the filter.  How much RNA do you get at the end?  Imagine an eye drop worth of liquid that contains 10 micrograms of RNA.  That’s 0.0001 grams and for comparison, a grain of rice weighs 0.015 grams.  It’s not a lot, but it’s enough to know if your sample is good or not.

screentapes

These ScreenTapes can analyze 16 RNA samples at one time. They are about the size of a long box of a glass slide or a ling box of matches

You still can’t “see” the RNA to know if it is all in one piece or if it’s been chomped up by RNases just by looking at this tiny bit of liquid in a tube.  You still have to analyze it, and to do this, I used a cute little machine called a TapeStation (I honestly have no idea why it’s called this, since the “ScreenTapes” that you use for the analysis – in the photo at left – look nothing like Tapes to me). This machine separates the RNA based on size (you can see that by the black lines in the image below).  There are two main sizes it looks at – these separate into to peaks (called 16S and 28S). If these RNAs have been chomped up, there won’t just be two peaks (or two black lines), but lots of little peaks of smaller sizes. This will indicate that the RNases were activated for some reason and the quality isn’t as good. In my experiments, the results were awesome and the RNA was of good enough quality for most experiments.  It also meant that the tumor tissue was handled really well when it was collected and didn’t sit on the counter or get thawed and frozen again, for example.

TapeStation

The two peaks are a graphical image of the separation of the RNA shown by the dark lines on the right.

Now you may be wondering, “what about my steak?” I honestly cannot encourage you to do this level of analysis to see if your steak’s RNA is high quality.  Then again, you just want to eat the steak – not do thousands of dollars of important experiments with it.  So let’s just consider the steak a useful scientific analogy and go start your grill – I’ve heard there are some steaks in your freezer.

Thanks to Kelli and Alia for asking me what experiments I’ve been doing and inspiring this blog post. 

How do you find a biomarker? A needle in the haystack.

biomarker_useBiomarkers are biological substances that can be measured to indicate some state of disease.  They can be used to detect a disease early, diagnose a disease, track the progression of the disease, predict how quickly a disease will progress, determine what the best treatment is for the disease, or monitor whether or not a treatment is working. Biomarkers have the potential to do so much, and identifying biomarkers for different steps in the health/disease continuum would help doctors to provide each individual with targeted, precision healthcare.  Biomarkers have the potential to save billions of healthcare dollars by helping prevent disease, by treating disease early (when it’s usually less expensive to treat), or by targeting treatments and avoid giving a treatment that won’t be effective.

spotthedifferencesWith all this potential, you would expect doctors to be using data from biomarkers to guide every single healthcare decision – but this isn’t the case quite yet.  First scientists have to find these biomarkers – a process often referred to as biomarker discovery.  I like to compare finding a biomaker to those “spot the differences” games where you have to look at two images and circle what is different in one picture compared to the other.  This is exactly what scientists do when finding a biomarker, except instead of comparing pictures, they are comparing patients.  And it’s not an easy game of “spot the differences” it’s complicated: the pictures are small and there are tons of details.

Let’s imagine a scenario that a scientist might face when wanting to find a biomarker for the early detection of pancreatic cancer.   Cancer is caused by mutations in the DNA, so you decide to look for DNA mutations as your biomarker for pancreatic cancer. So how do you “spot the differences” to find DNA biomarkers for pancreatic cancer?  First, you will need patient samples – maybe tissue or blood samples from a biobank that already has samples from patients with pancreatic cancer.  If samples aren’t already available, you will have to initiate a study partnering with doctors to collect samples from pancreatic cancer patients for you.  You will also need the second “picture” to compare the pancreatic cancer “picture” to.  This second picture will be samples from people who don’t have pancreatic cancer (scientists usually call this group the “control” group).  Then you have to “look” at the two groups’ DNA so you can find those differences.  This “looking” is often done by some genomics method like sequencing the DNA. This is where a lot of the complication comes in because if you look at all of the DNA, you will be comparing 3 billion individual nucleotides (the A, T, G, and Cs we’ve discussed in earlier posts) from each patient to each of the controls.  Even if you just look at the DNA that makes proteins, you’re still comparing 30 million nucleotides per patient.  And you can’t just compare one patient to one control!  Each of us is genetically different by ~1%, so you need to compare many patients to many controls to make sure that you find DNA that is involved in the disease and not just the ~1% that is already different between individuals.  But wait, we’re not done yet!  The biomarkers that you identify have to be validated – or double checked – to make sure that these differences just weren’t found by mistake.  And before biomarkers can be used in the clinic, they need to be approved by the Food and Drug Administration (FDA)

biomarker_discovery

From http://www.pfizer.ie/personalized_med.cfm


Whew… that was a lot of work! And so many people were involved: lead scientists who directed the project and got the money to fund it, researchers who do most of the work, computer people who are experts at crunching all of the data, and maybe even engineers to help run the equipment. Finding the biomarker needle in the biological haystack is difficult and takes time, money, and lots of people.  This is one of the reasons why there are only 20 FDA approved biomarkers for cancer (data from 2014).  But just because it’s difficult, doesn’t mean it’s impossible.  Furthermore, this effort is necessary to improve healthcare and decrease healthcare costs in the future.  It just might take a bit more time than we’d all like.

If you want to read more about the challenges and some of the solutions to biomarker discovery in cancer, take a look at this scientific article.  Or read about some successes from right in our backyard at Arizona State University on identifying biomarkers for the early detection of ovarian cancer and breast cancer.

 

What is a biobank? And why do scientists collect human tissue for research?

To understand what a biobank is and why they exist, it helps first to understand what type of “currency” is stored in the “bank” and what this “currency” will be used to purchase. Biobanks are a collection of “biospecimens” (the “currency”) and knowledge through research or preservation is often what can be “purchased” with this currency.  And as a quick FYI, biobank and biorepository are words that can be used interchangeably to describe the same thing.

Biospecimens can be any type of biological sample or material.  Seed biobanks, like the Svalbard Global Seed Bank in Norway, hold tens of thousands of seeds from over 4000 essential food crops.  The purpose of this biobank is to function as a back-up for seeds being stored in various countries. If a crop is wiped out because of disease or a zombie apocalypse, these seeds can be used to grow these crops again a biobank.

butterflies

photo credit Christian Guthier

The collection of birds, insects, butterflies, spiders and other animals and plants stored at the National Museum of Natural History at the Smithsonian Institute are also considered a biorepository.  There are a few reasons that these types of collections exist.  First, they are interesting to the public to show off the diversity of animals and plants found around the world and throughout time (I mean, who doesn’t like dinosaurs?).  But more than that, they are also immensely useful to scientists interesting in studying the animals themselves – including extinct animals, diversity, and evolution.

Biobanks that contain human tissue are most applicable to the study of humans and disease.  The biospecimens stored in these biobanks may include urine, blood, tissue (for example, extra tumor tissue removed during a surgery), feces (aka poop), cells (for example, cells scraped from the inside of the cheek or skin cells), cerebral spinal fluid, DNA or RNA.   The purpose of repositories that store tissue and fluids from people is to better understand diseases and use this understanding to develop molecular diagnostics and treatments. How is this done? Generally, scientists will compare biospecimens from many patients with a particular disease (for example, tumor tissue removed during surgery from patients with breast cancer or blood from patients with diabetes) to samples from patients who do not have that disease using one of those “-omic” analyses. Through understanding what causes the disease, methods can be devised to better detect the disease early or treatments can be developed to target the cause.

biobank_purpose

But you may be wondering how tissue biorepositories exist at all?  It is all because patients have been gracious enough to contribute some tissue, blood, skin, or nails for researchers to use in their research.  Biorepositories do not own this tissue and neither do the researchers – we are merely custodians of the tissue with the ultimate purpose to use the biospecimens for research.  The patient always comes first. Therefore, the first thing that is done before collecting tissue for research is to talk to the patient and explain why it is biobankers would like to collect and store their tissue.  The risks are explained and we ask for their permission through a process called informed consent (more on this in future posts).  If a patient does not consent to donate tissue for research, this does not affect their care in any way whatsoever.  It is the patients choice.  However, if they do agree to donate tissue, it will either be collected in the operating room (in the case of tumor tissue) or in pathology.  This tissue collection never disrupts medical care or diagnosis.  If all of the tissue is needed for diagnosing the patient, then that’s what happens and none is collected for research. Again, the patient and their medical care always come first.  If we are able to collect samples, they are stored in liquid nitrogen tanks until they are requested by a researcher.  We then make sure that the samples safely get to the researcher.biobank_workflow

Thousands (likely hundreds of thousands) of studies have relied on biospecimens to better understand the underlying disease in or to develop treatments.  For example, tissue from melanoma patients was used to identify a mutation found ~50% of patients who have melanoma.  This mutation can be specifically targeted by a drug that significantly improved progression-free survival in patients who typically have a dismal prognosis.  Even more studies on ongoing, with the goal of using knowledge gained from these priceless biospecimens to reach the promise of personalized medicine.