Team:KULeuven/Project

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Project brainstorm

Favourite previous iGEM projects


Maarten Breckpot


Nathalie Busschaert


Jonas Demeulemeester

  • Virotrap Ljubljana 2007
  • RNAi enhanced logic circuit Princeton 2007
  • Other nice parts/devices:
    • Caltech: Riboswitch design for targeted cell death/molecular sensor
    • Cambridge: Inducible bigger pore protein for E.coli
    • Harvard: Quorum-sensing & targeting!
    • Melbourne: Red/blue light responsive system through chimeric photoreceptors-kinases
    • Peking U: λ-based bistable switch = very powerful
    • UCSF: compartmentalization! Rewired MAPK cascade signaling through scaffolds ≅ circuit board


Andim Doldurucu


Jan Mertens


Benjamien Moeyaert


Stefanie Roberfroid


Hanne Tytgat


Elke Van Assche


Nick Van Damme

--> idea: solve a nice mathematical problem

--> idea: build an integrator to solve your own ODE's, also build a differentiator to make a PID-controller


Antoine Vandermeersch


Dries Vercruysse


Sigrid De Keersmaecker

iGEM judging tracks

  • Foundational Research - basic science and engineering research
  • Information Processing - genetically encoded control, logic, and memory
  • Energy - biological fuels, feedstocks, and other energy projects
  • Environment- sensing bioremediation of environmental state
  • Health & Medicine - applied projects with the goal of directly improving the human condition

Other

Idea exchange - iGEM ideas posted by other teams

Ideas for our project

A first idea: cancer treatment with genetically modified blood cells

As cancer cells need a lot of energy to replicate themselves, they should be well provided with blood. Therefore, blood cells could be the right choice for in situ treatment of cancer. First, we should immobilize these blood cells on the cancer cells. Subsequently, these blood cells should secrete specific agents that reduce the activity of the cancer cells. (These 2 steps may come in handy if we want to split up in 2 subgroups)

Notes

  • Sounds like a great idea! Anti-angiogenic therapy is one of the big hopes for anti-tumor treatments. But let's keep in mind that angiogenesis (the formation of blood vessels) is only a late hallmark of tumors (more about these hallmarks of cancer -PDF). It is however a significant barrier to break through if the tumor has to grow past a certain (very limited) size. So this would be more like a therapy for later-stage malignancies, which would also be great because it's often the metastasis (the spreading of) of the tumor that is causing the more visible effects of the cancer. (pain, deterioration, ... and eventually, if untreated death). - Jonas 12:09, 23 May 2008 (UTC)
  • Anyhow, if we proceed with this idea, it will be a challenge to get everything ready and produced in the erythrocyte (red blood cell) before it loses it's nucleus and thus also the ability to initiate de novo transcription. And to keep all this machinery silent in non-docked erythrocytes. I'm liking this challenge though. Besides this has an upside as well as I feel that consequences would be less severe in this non-cell if things go awry in the system. :) - Jonas 17:30, 23 May 2008 (UTC)
  • I just thought of something that might be quite critical. If I recall correctly, there are 3 main ways in which tumors acquire blood supply.
  1. The first one is through a recapitulation of embryonic development. This is the recruitment of vascular endothelial precursors or the activation of local endothelium via factors like VEGF (angiogenic sprouting or intussusceptive growth). In this case, the 'vessels' of the tumor blood supply are lined mostly with endothelial cells which are actually NOT malignant, but are kind of working together with the tumor cells.
  2. A successful cancer metastasis (a secondary tumor, derived from the original) will co-opt blood vessels and these will thus also be lined mostly with endothelium cells.
  3. The third way to achieve blood supply is through vasculogenic mimicry, where the tumor cells actually DO line the bloodstream and mimic the normal vascular endothelium. Here tumor biomarkers should be directly displayed to the passing erythrocytes and would thus be potential targets for use in this approach.
OK, now for my point. In all these cases the vessels are highly abnormal, both structurally and functionally. They've got many holes, inhomogeneous bloodflow, are leaky, ... so it's very likely there will be exposed markers we can focus on but this will probably not always be the case. But anyhow, I'm really liking this idea! - Jonas 14:17, 23 May 2008 (UTC)
  • There will be a lot of challenges. Some things that popped in my head: 1)What is the progenitorcell we're going to work with. When you use stemcells, you have to differentiate them in vitro into red blood cells which is pretty delicate matter. 2)finding the right markers for the recognition that are not expressed on normal cells. 3) developing an assay that proves that it works. Whith tis idea there are a lot of factors that have to be taken in account and the question is if we will get a positive result in 3 months time. There's a lot of ongoing research and a lot of things ar not yet known. But I also like the idea, next year I'm going to do my thesis about lymphangiogenesis so I'm very interested in the subject :)- Jan
  • On the biomarker issue. There's a lot of this kind of proteomics research going on at the Biology faculty/GHB. I hope we could pick up some molecules there? Because starting our own search for these and getting results in 3 months time would be quite hopeless indeed - Jonas 23:46, 23 May 2008 (UTC)
  • I agree that working with RBC will be quite a challenge. But maybe we can use bacteria with the right proteins, just to proof the principle. If it works, another team (next year?) or research group can then try to apply this principle on RBC. Anyhow, I also really like this project. --BNathalie 16:18, 24 May 2008 (UTC)
  • We could overcome the differentiation problem if we work with a mouse model for example. We harvest (or get them from someone) CD34+ hematopoietic progenitor cells (or other progenitors, I don't know), transfect these with our constructs + maybe an extra marker like green fluorescent protein (GFP) and then reintroduce these cells into the mouse. Differentiation should proceed normally then and we could harvest the modified and differentiated red blood cells (RBCs) by FACS analysis or something similar. The problem is that I've got no idea how long a procedure like this could take and we should be sure that our constructs work properly before trying this. We could also attempt myeloablative treatment on the mouse before reintroducing the transfected cells, this would make reharvesting a lot easier but once again, no idea how long this takes ... On the other hand, if we could harvest the modified RBCs, an in vitro assay should be quite feasible. - Jonas 22:06, 24 May 2008 (UTC)
  • I've been thinking about the agent we have to deliver in order to kill the cancerous cells. We could deliver Reactive Oxygen Species (ROS) like hydroxyl radicals, superoxide, hydrogen peroxide or singlet oxygen to the tumor. This could potentially be very hazardous or lethal to the tumor cells since they often have defective DNA repair machinery and would thus be unable to cope with this amount of damaging. The erythrocyte vessel we target to the tumors is extremely well fitted to do this since it's packed with iron that could potentially catalyse the production of a lot of these ROS via the Fenton reaction etc. So all that should happen after the erythrocyte docks to the cancerous cells would be to destroy some hemoglobin, set some iron free in the red blood cell and let ROS be created locally! - Jonas 09:00, 24 May 2008 (UTC)
  • One last thing. The entire erythrocyte metabolism has been simulated in silico (including links to hemoglobin). So this project could also provide enough entertainment for the more modeling-oriented amongst us :) - Jonas 23:12, 25 May 2008 (UTC)

A second idea: bacteria clean virusses in animals

This is an improvement of the idea of Ljubljana: we cannot reprogram the immune system, but we can reprogram bacteria. So, what we could do is make bacteria produce viral receptors (challenge 1) which are modified so that when a virus attaches to them, a restriction enzyme is transcribed (challenge 2). This RE degrades the viral DNA and the bacterial DNA, thus killing the bacterium. This way, the bacteria clean all virusses from the body. When this is established, we can induce a suicide signal for the bacteria (challenge 3). Big problems:

  • Is it possible to make a eukaryotic virus attack a prokaryote (also a fundamental question)?
  • Immunogenicity bacterium (cf. Bactoblood)! Bmoeyaert


  • I'm probably risking to get banned for nagging because of this. :P I think the tricky part would be the preferential docking of the viruses on the bacteria if you've got about 10^14 of your own cells in your body. Even if only a small subset of these would be targets for the virus, I believe the ratio of bacteria to host cells would be quite low unless you allow a very large 'bacterial infection'. This problem might be overcome if the viral receptor density is way higher on the bacteria. - Jonas 17:52, 23 May 2008 (UTC)
  • Cool stuff though, the opposite system exists. A bacterial infection could be treated by administering the specific bacteriophages, here the system can also co-evolve. Problem is that you have to know the bacterial strain of the infection in order to administer the correct phage, and this can take a while. - Jonas 17:52, 23 May 2008 (UTC)
  • It's an appealing concept. An eukarotic virus only has to cross the celmembrane to get its content into the human cell. When we would use E.coli, the virus would have to get first through the outermembrane, then through the peptidoglycane and then through the innermembrane. So how does it get it in the cytoplasm? But maybe this is not necessary and is it sufficient to let the virus cross the outermembrane and come in the periplasm. If this induces the cell to do apoptosis en kill itself, including the virus, we've got a nice system. But like Jonas said, there will always be virusparticles that infect human cells, wich are in the majority. But still, it would be quite an accomplishment to get an eukariotic virus to infect a bacterium.-Jan

A third idea: Bacteria that control the amount of drugs

It's known that the effect of drugs on a human being is very dependent on the metabolism of that person. There are extensive metabolizers, people who have a normal response to a certain drug. Intermediate metabolizers show a low response and in poor metabolizers there's very little effect. Poor metabolizers need a higher amount of drugs to respond, where ultra fast metabolizers need a lower dose. These differences in the drugmetabolism in different people is a big concern, because a wrong dose can have severe consequences. There's a need for patient-focussed therapy. If we want to know which type of metabolizer a person is, we have to know his genotype. This is a very expensive and time-consuming procedure. Wouldn't it be nice to develop a two bacteria-system that can replace genotyping? I' m thinking of two bacteria that live together in the intestine. The first bacteria has a sensor function. It has to monitor if the amount of the drug that is present in the intestine, is efficient. This bacteria has to signal his observations to the second bacteria. This second bacteria is the drug-producer. Like some probiotics, that are already on the market, it produces the drug at the location where it's needed. The amount of drug it produces would be controlled by the other bacteria. In case the amount of treatment is enough, the first sensor-bacteria represses the second one. If the drug level drops again, the sensor-bacteria should re-activate the drug-producing one. In that way there's a feedback loop between the two bacterias and one can control the amount of treatment that's needed. --Hanne 19:27, 23 May 2008 (UTC)

  • I don't think you necissarily need a 2 bacterial strain system and can also do it with one bacterial strain that has sensor- and drugproducer function. When it monitors the amount of drugs it can autoinduce itself to produce the drug and repress itself when it's enough. like the idea and think it's possible to do this in 3 months. It's also an idea in which I see our different skills can be integrated (the engineers can do modelling of pharmacokinetics for example), In the first 2 ideas that's maybe more difficult -Jan
  • I would streamline the idea further:
    • Use a single probiotic bacteria (lots of available expertise on probiotics in the team)
    • Use a peptide or protein drug - probably a lot easier than synthetisizing a small molecule
    • As probiotic bacteria live in the gut, peptide or protein drug could probably enter the blood stream
    • Make a sensor for a signal that indicates the reaction to the treatment
    • I was thinking about Crohn's disease (because it happens in the gut). Produce a peptide such as vasoactive intestinal peptide (potential treatment for Crohn). Sense the inflammatory response present in the gut. If high inflammation, increase drug production - up to some maximum dosage to avoid overdosing. Do not respond too fast to avoid overdosing.
    • Crohn's expertise available in Leuven (P. Rutgeerts, S. Vermeiren) --Yves
  • I also like this idea. However, you can't really control how long the bacteria stay inside your gut. So I think this is a system that is best used for chronic conditions (like Crohn's disease) that require continuous treatment. I like the example of Crohn's disease, because you can build in a good control devise to avoid overdosing. In this system, we need a bacteria that produces a drug only when: a) there is a low concentration of the drug inside the gut, and b) when the gut is inflamed. Practically, this means a receptor that will stop the production of the drug upon binding to the drug. I don't know how to sense inflammation though. --BNathalie 16:35, 24 May 2008 (UTC)
  • I was indeed thinking of applications for chronic disease.
  • In the case of Crohn's, I think it would be quite doable to sense inflammation as there are many molecules typical of this process. We would have to look up which ones though.
  • An additional advantage is that Crohn's disease is characterized by local inflammation, so that the system would probably produce more drug exactly where it is needed most. --Yves
  • I also like this idea. Like Jan says it's a project were we are going to need all our different skills. Maybe this is more interesting for the engineers among us because it needs a lot of modeling. --stefanie
  • As an engineer this also seems the most challenging proposal. To regulate the proportion of drugs it seems that we are going to need a PID-controller (proportional with the amount already available, integrating to keep the level steady and differentiating to avoid responding too fast). It would be very challenging if we could also achieve this kind of controlling system in the bacteria. --Nick
  • Genetically modified Lactococcus lactis bacteria constitutively expressing Interleukin-10 (anti-inflammatory) are already in stage I clinical trials for the treatment of Crohn's disease. The dosage regulation by sensing could be a very nice addition to a system like this. I don't know however to what degree Crohn's disease is temporally variable and thus might benefit from such a system. Jonas 23:28, 25 May 2008 (UTC)
  • I think you see it somewhat wrong. It's about sensing what amount of drugs a certain patient needs. So there is a variable, not only in one patient, but also between different patients! It's about sensing how much every person needs. I think the idea of implementing this system for the treatment of Crohn's disease is really interesting. It's true that Lactobacillus lactis already delivers the drugs at the right spot in the body, but the control mechanism isn't there yet. So I think we could make an important improvement to this approach. This system can than serve as a model for treating other diseases. --Hanne 09:13, 26 May 2008 (UTC)
  • The reference signal for the PID would simply be the local inflammation, but does this mean the bacteria would extract no information about the specific metabolism of the host (person)? If it would, the PID-controller could be optimised for every person by means of self-tuning (retrieving optimal parameters that characterise the PID-controller behaviour and determines it stability). Anyway, I like this idea a lot. --Avdmeers

Our project

Abstract

Our project details

Part 2

The Experiments

Part 3

Results

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