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Anti-Cancer

Posted by Chris on February 20th, 2014  ⟩  0 comments

I believe that our current quality of life has been most affected by the discovery of vaccines, even more so than by our use of antibiotics. I also firmly believe that the benefits of those vaccines outweigh any and all side-effects, disadvantages and the scare-mongering tirades about inerudite, nonsense-driven “research”. I am personally, extremely ecstatic that I never had to worry about getting polio or mumps or rubella. Though the shots hurt like crazy at the time, I can now silently thank my parents for listening to the “advice” of knowledgeable doctors and scientists who promised them I could have a better chance of life than the one their parents lived with. t is advice that I have also chosen to listen to for my own children, rather than let them fall prey to the ravages of the most terrifying diseases and plagues that our species has dealt with so poorly throughout millennia…until only just these last hundred years or so.

Unlike antibiotics, vaccines work with our body’s natural defenses by helping to build an initial bulwark against the specific antigens of a disease that can then be repopulated at a later time in the event that the disease manifests. You can think of vaccines more like an underground, resistance force laying the groundwork for a potential invasion as compared to an antibiotic’s nuclear missile strike after the invasion already took place. That cooperative action also means that we don’t have to worry about things like developing immunities to vaccines, since they are not the main actors on the stage of combat, only the catalysts for better host immune response.

There are, of course, some inherent risks involved with vaccines. Attenuated microorganisms in some vaccines may go rogue and develop into the full-fledged disease they originated from. A person’s immune response may also go hyperactive against the vaccine dose, causing traumatic problems. In therapeutically vaccinated patients, there may not enough of an immune response left in the body (for any of a variety of reasons) so that vaccination does little to help sufficiently subdue the disease. These are not trivial matters, to say the least, and doctors and scientists are constantly working to create better and more efficacious vaccines or vaccination systems. Recently, a group from the University of Navarra in Spain, under Juan Jose Lasarte, may just have found a novel method to improve how we produce vaccines.

Lasarte’s team had already previously discovered that the fusion of the Extra Domain A (EDA) of fibronectin to an antigen leads to an increase in its association with TLR4-expressing dendritic cells, causing greater immunogenicity of the antigen and greater induction of immunity. But the fusion of EDA to every single, different antigen is time-consuming, problematic and prohibitive. But what if they could find a more universal approach to creating the fusion? Lasarte’s team focused on building a hybrid EDA-linked streptavidin recombinant protein that could be simply and easily linked to any biotinylated antigen or protein due to the high affinity streptavidin naturally has for biotin. They called their new protein the “EDAvidin”.

One of the most important aspects of the streptavidin-biotin interaction is the requirement of the tetramarization of the streptavidin protein. Through a series of tests and comparisons, Lasarte’s group could see that the new EDAvidin still formed into the tetramer orientation required for optimal biotin interaction. Even better, they biotinylated an ovalbumin (OVA) protein (using something very similar to one of Gold Bio’s Biotin Labeling Kits) and successfully pulled the OVA proteins out of solution using EVAvidin in an ELISA assay. The binding affinity wasn’t quite as good as the original streptavidin-biotin, reaching only to 10-14 as compared to the original’s Kd of 10-15, but that’s still really good! The EDAvidin also maintained the proimflammatory activity that they noted in their earlier work with pure EDA, producing an immune response in the T cells of mice similar to that of antigens linked only to EDA.

All in all, EDAvidin presents the best of both worlds: a method to produce better acting vaccines that can be ubiquitously used with any protein that can be biotinylated, which is pretty much any protein. Lasarte’s method may end up becoming the building block for an entire new system of vaccine therapy, leading to better cancer tumor control and immunoresponse. I think that it’s just another brilliant use of an already brilliant system.

 
 

Arribillaga, L., Durantez, M., Lozano, T., Rudilla, F., Rehberger, F., Casares, N., Villanueva, L., Martinez, M., Gorraiz, M., Borrás-Cuesta, F., Sarobe, P., Prieto, J. & Lasarte, J. J. (2013). A Fusion Protein between Streptavidin and the Endogenous TLR4 Ligand EDA Targets Biotinylated Antigens to Dendritic Cells and Induces T Cell Responses In Vivo. BioMed research international, 2013.

Category Code: 88241 88231


 

PS. For an awesome example of what vaccinating does for us as opposed to not vaccinating, you can check out Penn and Teller explaining it in their unique, condescending (and humorous) way.

 
 

Posted by Chris on January 9th, 2014  ⟩  0 comments

One of our goals at GoldBio is to constantly review new products or product groups that we believe are beneficial to our scientists. Most recently, we added a line of protein labeling kits, either with biotin, streptavidin, HRP, or fluorophores (like CY3 and CY5). Since I have not worked a great deal with biotin labeling, and it’s typically subsequent streptavidin binding, I happily delved into the remarkable world of biotin-streptavidin research to find out more information.

Even in general, the biochemical interaction between this small bacterial protein and the essential vitamin is spectacular. The interaction between biotin and the various avidins is one of the strongest non-covalent bonding we have witnessed in nature, with a dissociation constant of over 10-14 M! So when these two molecules hook up, there’s not a lot that can separate them. Scientists have been utilizing this interaction since the 70’s, though it took us until almost 1990 before the crystal structure was discovered (and we started to truly understand why it’s so strong) and until the later 90’s to find a simpler method of dissociation to make the system even more robust. But for me, the why it works is less important than the ever-increasing number of how to use it.

Our available GoldBio kits are used more for general detection, purification or quantification of your proteins. Those are all very important and useful technologies and ones we’re excited to offer. Then there are scientists like Jung-Joon Min, Jong-Oh Park, and Sukho Park out of Chonnam National University in South Korea who are using the biotin-streptavidin interaction to build a drug delivery system (DDS) they are calling “bacteriobots”; a bacteria-driven and self-propelled, tumor-homing, chemotherapeautic fusion bomb!

The science all seems more sci-fi than real. It calls for utilizing the natural tendency of an attenuated version of the bacterium, Salmonella typhimurium (S. typhimurium), which is known to specifically drive toward and target various types of cancers (including breast and colorectal), as a microactuator and microsensor. They coated the bacteria’s surface with sulfhydryl-activated biotin and microbeads (which would optimally carry the chemotherapeutic agents) with streptavidin. Combining the two gives you something that looks like this:

Bacteriobots

Previously, there has been some exciting, new interest in a similar system that utilizes magnetotactic beads and a system of electromagnetic coiled springs to direct the bead movement. But these new bacteriobots seem superior in that they are self-propelled and the S. typhimurium selectively target and proliferate in the tumor cells they are intended to destroy. Overall, it’s reminiscent of fantastical stories of nanobots flooding around our bodies, continuously fixing and repairing our bodies to near immortality. This technology has only been tested insofar as its homing ability and proof of concept. The Chonnam group has not yet tested this system against tumors with actual chemotherapeutic agents to see if it will subsequently reduce the tumors as believed. But perhaps the fanstastical will become ordinary far sooner than we think.

 
 

Park, S. J., Park, S. H., Cho, S., Kim, D. M., Lee, Y., Ko, S. Y., Hong, Y., Choy, H.E., Min, J-J., Park, J-O., & Park, S. (2013). New paradigm for tumor theranostic methodology using bacteria-based microrobot. Scientific reports, 3.

Category Code: 79105 88221 88261

Posted by Chris on December 4th, 2013  ⟩  0 comments

In the universe of cancers, there are an overabundance of different types. Not just in terms of where a particular cancer tends to show up (such as ovarian cancers, prostate cancer, etc.), but in how the cancer grows or spreads. In fact, apart from the obvious broader categorization that doctors have assembled over the last century and some smaller, subcategorizations that have happened more recently, it could be argued that every single instance of cancer is as unique as the person who has it. And why wouldn’t that be the case, after all? Every individual person has a unique genetic structure, and cancers are caused by defective genes gone awry, so it stands to reason that each cancer is technically as unique as any one person’s individual DNA.

Of course, there are millions of genes that are virtually identical in everyone…the genes that make my intestines work are probably 99.99% identical to the genes that make your intestines work. That’s just good evolutionary conservation. That also explains why cancers can be categorized at all. In the larger framework of things, our bodies are not so different. The metabolic pathways in me are mostly the same as in everyone else and any single, specific gene in one person will get upregulated or downregulated by the same growth factors as the next person.

However, that uniqueness that encompasses each one of us DOES change something in the equation. It answers (without really answering at all) why treatments respond for with some and adversely for others. It explains why cancer can sometimes be annihilated fairly easily while other times relapsing over and over again.

Compounding that penchant for variety is the problematic approach to screening new therapeutic agents. Typically, new drugs are tested first on in vitro cancer cells that have been propagated extensively over decades. But these same cell lines are far removed from the malignant tumors they are derived from. The development of the soft agar assay did wonders for our ability to study cancer outside of a patient and far removed from the threat of death. However, at the same time, they have created an artificial environment which is non-similar to the complicated mass of tumors, their supportive stromal and hematopoietic cells, and their entire vasculature. This dissimilarity makes for a large drop-off rate between in vitro and in vivo trials, eats up valuable resources and takes time away from patients who need viable options.

More recently, some doctors have grown adept in a procedure called Patient-Derived Xenograft (PDX). In a PDX, a graft of the tumor is transplanted directly into a recipient host; usually an immunocompromised mouse or rat. These PDX are usually transplanted somewhere generic, such as the subcutaneously near the hind quarters of the animal and can more closely recapitulate the biological environment that the tumor required to subsist. Current PDX methods aren’t perfect though. Some cancer varieties, such as breast cancer, are resistant to the act of xenotransplantation for some reason while others, like melanoma or lung, are much easier to graft. Regardless, PDX is providing an excellent opportunity to study and screen potential therapies on a growing variety of cancers, in something very similar to their natural setting.

In late 2011, a group from the John Hopkins University School of Medicine, led by Gary Gallia, managed to successfully transplant Chordoma into athymic mice! All by itself, that was a remarkable achievement. Chordoma is an insidious type of cancer, a bone cancer, but one that only grows in the skull or spinal portions of our body. It forms from remnants of our vestigial notochord and grows slowly and is usually diagnosed only in an adult. It is currently treatable only with surgery to remove the tumor, followed with radiation therapy to deal with what was missed in the surgery. Metastasis occurs in about 20% of patients and the 10 year survival rate is only about 46% with a median survival of patients of 6-7 years.

Then, earlier this month, Gallia’s group trumped their earlier chordoma PDX with a chemotherapeutic inhibition of the chordoma-grafted mice using either erlotinib or gefitinib, two popular EGFR (Epidermal Growth Factor Receptor) inhibitors, demonstrating the efficacy of this approach for chordomas. Overall, they saw a 70-75% reduction in tumor size after nearly double the time post-PDX.

As good as PDX is for replicating cancers in vivo, ultimately it is more useful in an academic setting than a clinical one. It will never produce results fast enough to provide the magic pill that will rid a patient of their immediate cancer. But it is an important step in the research of cancer and one I believe will continue to shed light onto a dark and convoluted metabolic pathway.

Chordoma Xenograft

 
 

Siu, I. M., Ruzevick, J., Zhao, Q., Connis, N., Jiao, Y., Bettegowda, C., & Gallia, G. L. (2013). Erlotinib Inhibits Growth of a Patient-Derived Chordoma Xenograft. PloS one, 8(11), e78895.

Siu, I. M., Salmasi, V., Orr, B. A., Zhao, Q., Binder, Z. A., Tran, C., & Gallia, G. L. (2012). Establishment and characterization of a primary human chordoma xenograft model: Laboratory investigation. Journal of neurosurgery, 116(4), 801-809.

For some additional, informative reading on PDX:
Williams, S. A., Anderson, W. C., Santaguida, M. T., & Dylla, S. J. (2013). Patient-derived xenografts, the cancer stem cell paradigm, and cancer pathobiology in the 21st century. Laboratory Investigation, 93(9), 970-982.

Category Code: 88221 88241 88231