Environmentally Controlled Invasion of Cancer Cells by Engineered Bacteria

1. Environmentally Controlled Invasion of Cancer Cells by Engineered Bacteria

2. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Background • Since 1999, Cancer is the leading cause of death in the U.S. for people under 85. • There have been numerous approaches on how to control and cure cancer. • One way is to use proteins present in bacteria, that allow interactions between bacteria and cancer cells. • They engineered bacteria to interact with cancer cells depending on different environments. 2

3. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Background • Using the invasin gene encoding invasin, the quorum sensing lux operon and AHL inducible lux promoter, the fdfH hypoxia responsive promoter, and the arabniose indubicle araBAD promoter, they engineered bacteria to invade mammalian cells that express beta-1 integrins. • Their goal was to design a new approach to engineer bacteria that would sense the environment of a tumor and destroy them. 3

4. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Key Terms • Invasin is a long rigid protein that extends about 18nm in length and binds tightly to beta-1 integrins that are expressed by some mammalian cells on their surface. • The cancer cells they chose to invade were HeLa HepG2, and U2OS lines. 4

5. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Experiment 5

6. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Experiment • They constitutively expressed invasin under the tet promoter (pAC-TetInv) in a medium-copy plasmid. • On a side note, the strain of E. coli they used make type I pili (which bind to mammalian surface carbs) encoded by the fim operon, so their plasmid contains a deletion strain (CAMC600). • To determine how type I pili affected the ability to invade, they also transformed CAMC600 with pAC-TetInv 6

7. Introduction • Background • Key Terms • Experiment • Results • Discussion Introduction Experiment 7

8. Introduction • Results • fdfH + araBAD in a BAC (Bacterial Artificial Choromose) plasmid • Lux, quorum circuit with GFP • Discussion Results fdfH + araBAD in a BAC (Bacterial Artificial Choromose) plasmid 8

9. Introduction • Results • fdfH + araBAD in a BAC (Bacterial Artificial Choromose) plasmid • Lux, quorum circuit with GFP • Discussion Results Lux, quorum circuit with GFP 9

10. Introduction • Results • Discussion • Likes and Dislikes Discussion Likes and Dislikes I liked their new approach in serving cancer. Demonstrated how one protein, invasin, can be used in destroying tumor cells. Created an inducible and constitutive system in E. coli to attack the same cause. Allowed us to see two different views in targeting tumor cells. I disliked the invasin protein. Invasin binds to beta-1 integrins which are not on every cell, so if they were to somehow create a treatment using invasin, it would only work for some cancers. 10

11. Introduction Results Discussion Sources Pictures from: Anderson JC, Clarke EJ, Arkin AP, and Voigt CA. Environmentally controlled invasion of cancer cells by engineered bacteria. J Mol Biol 2006 Jan 27; 355(4) 619-27. Cancer cell photo from: http://www.newscentre.bham.ac.uk/press/2007/10/Cancer_Cold_Virus_03_10_07.shtml That 1 cancer fact was taken from: http://jnci.oxfordjournals.org/cgi/reprint/97/5/330.pdf 11