My iGEM Team: Fighting Colorectal Cancer with Engineered Bacteria
Why I Started This Project
Colorectal cancer is one of the top three most common cancers worldwide. The tough part is that it’s usually caught late, when treatment is harder and harsher. Surgery, chemo, and radiation often hit healthy cells too, leaving patients with painful side effects and weak immune systems.
I wanted to see if synthetic biology could offer a smarter solution: something precise, gentle, and controllable. That’s how this project began.
What I Built
I designed an engineered E. coli therapy system—basically programming safe probiotic bacteria (E. coli Nissle 1917) to fight cancer in the colon. Here’s how it works (in my words):
- Finding the Tumor 🧭 I gave the bacteria a “GPS” protein (HlpA-INP) that makes them stick to molecules (HSPGs) found mostly on tumor surfaces.
- Switching Them On with Light 💡 Using a red-light sensor (PadC-MrkH), the bacteria only activate when I shine a 710 nm red light. Red light penetrates deeper into tissue than blue, which makes it a better “remote control.”
- Delivering the Attack 🎯
Once switched on, the bacteria can:
- Produce coagulase to block blood vessels feeding the tumor,
- Release HlyE or other proteins that directly kill cancer cells,
- Or even express immune-boosting molecules like PD-L1 nanobodies.
- Built-in Self-Destruct ⏳ To keep everything safe, I added a suicide system: when red light is turned off and arabinose sugar runs out, the bacteria self-destruct. That way, they don’t spread or linger in the body.
My “Smart Capsule” Idea
Instead of invasive treatment, I imagined a suppository capsule that contains freeze-dried bacteria, a bit of arabinose, and a tiny LED that shines red light.
- Insert → capsule dissolves → bacteria are released,
- Turn on the LED → treatment begins,
- Turn off → bacteria self-destruct.
It’s local, non-invasive, and controllable.
What Makes This Special
| Part of System | Why It’s Cool |
|---|---|
| Red Light | Works deeper in tissue than blue light, activates in minutes. |
| Tumor GPS | Sticks to cancer cells but not healthy colon tissue. |
| Multi-attack | Can block blood supply, kill tumor cells, and boost immunity. |
| Failsafe Kill Switch | Double-checked safety—no bacteria left behind. |
| Smart Delivery | Remote-controlled suppository = simple but powerful. |
My Progress So Far
- ✅ Built and tested the red-light system—it responds quickly.
- ✅ Proved that my “GPS protein” helps bacteria gather on tumor cells in lab models.
- ✅ Expressed coagulase successfully and saw it cause blood clotting in tumor vessels.
- ✅ Designed and tested the suicide switch—worked as planned.
- 🔜 Next step: testing the whole system in animal models.
Why This Matters to Me
This project isn’t just about science—it’s about rethinking how we fight cancer. Instead of blasting the whole body with toxic drugs, we can imagine therapies that are smart, local, and safe.
Working on this has taught me how to combine biology, engineering, and even a little design thinking (like the LED capsule idea). More importantly, it’s shown me how much dedication it takes to turn a crazy idea into something that might actually help people.