Non-small cell lung cancer (NSCLC) has one of the highest mortality rates due to late presentation of symptoms. There is currently no cheap and effective means for the early diagnosis of NSCLC. Abnormal microRNA (miRNA) expression levels in body fluids can be used as effective biomarkers for a myriad of diseases by non-invasive methods. miRNAs hsa-mir-15b-5p and hsa-mir-27b-3p are differentially expressed in preliminary stages of NSCLC. We designed two sequence specific sensors to quantify the serum levels of these miRNAs. Our sensors utilise synthetic riboregulators, called toehold switches, that regulate protein synthesis post-transcriptionally. Translation can be activated by the binding of an arbitrary RNA sequence to the toehold switch. Using these specific miRNAs obtained from serum to activate the toehold switch, a downstream fluorescent reporter protein is produced. The intensity of fluorescence is indicative of miRNA levels. We hope that this work will establish a proof of principle for the use of toehold switches in the quantification of miRNA levels as a simple detection method for NSCLC. In the future, we propose that multiple switches could be used in tandem to detect differentially expressed miRNAs in multiple diseases simultaneously, or even several reporters with different emission peaks could be used to create a multiplexing assay. This could allow for rapid and cheap diagnosis of many diseases from one sample.
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=== Collaboration ===
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We'd love to work with other iGEM teams - come and say hi to us on [https://twitter.com/clsbigem Twitter], or email [mailto:igem@cityoflondonschool.org.uk igem@cityoflondonschool.org.uk].
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Revision as of 22:51, 14 October 2017
Project BATMAN
a new way to detect cancer using toehold switches
Late presentation of symptoms is the main reason
why 40,000 people are dying every year from lung cancer
Dr Sujal Desai, Respiratory Consultant
We developed a new way to detect cancer at an early stage by measuring micro-RNAs (miRNA), biomarkers
found in blood. We used toehold switches to regulate expression of GFP in response to specific miRNAs. This method
could be applied to a myriad of diseases, but we have chosen to use non-small cell lung cancer as a proof of concept.
Biomarkers in the blood
Abnormal levels of miRNAs mir-15b-5p and mir-27b-3p in blood serum are
indicative of NSCLC[2]. We have designed two sequence-specific sensors
that utilise synthetic riboregulators called toehold switches. These toehold
switches detect mir-15b-5p and mir-27b-3p and produce fluorescent
reporter proteins in their presence. We designed our sensors to work in a
cell-free system, allowing them to be used safely and in a low-tech
environment.
