Scientists have announced the creation of miniature tumours that closely mimic real cancers.
Geneticists at the Wellcome Trust Sanger Institute in Cambridge, UK, used cells from colon cancer tumours to grow 'organoids' - tiny three-dimensional clumps of tumour cells, just 0.1mm in diameter - in the lab. They found that the organoids shared many of the properties of the original tumours and used them to successfully test over 80 cancer drugs, identifying at least one promising new candidate.
'The beautiful thing here is that we've shown we can grow these organoids in the lab and they look a lot like the tissue from which they were taken, so they should be much better models for studying cancer,' Dr Mathew Garnett, a senior author of the paper that was published in Cell, told the Guardian.
Although cancer cells grow rampantly in the body, once they are put into a Petri dish they are hard to keep alive. While cancer cell lines have been grown, these don't tend to behave much like real tumours as they start to develop their own mutations. Tumours can also be grown in immune-deficient mice, but in this case it is hard to conduct large-scale drug tests.
Dr Garnett and his team used the concept of organoids, which had been developed as models of healthy tissue, to create miniature 3-D tumours. They took cells from biopsies of 20 patients with colorectal cancer to create 22 cancer organoids, and used the patients' healthy tissue to create 19 healthy organoids. They found that the cancer organoids displayed the hallmarks of the original tumours in terms of their 3-D architecture, the cell types present and their genetic profiles.
Next they screened the organoids using 83 approved and experimental cancer drugs. It is well known that some genetic mutations will cause a tumour to be resistant to a particular drug, and the organoids displayed the same sensitivity to the cancer drugs as would be expected given their specific mutations.
One organoid with a mutated RNF43 gene was destroyed by a drug that blocked a protein called porcupine, suggesting that this drug might be useful in patients whose tumour shares that mutation.
'Cancer is a very diverse disease and we often find that some patients respond to a drug while others don't. The reasons are often poorly understood, but we can use the organoids to try and understand that better,' said Dr Garnett in the Guardian. 'Ultimately this living biobank should enable us to identify populations of patients that we can predict will be most likely to benefit from a specific drug,' he added.
The researchers now plan to grow organoids for other types of cancer and to use them to test new cancer drugs.