Using PDOS to prevent and treat cancer in FAP and MAP patients
What is meant by FAP and MAP?
Familial Adenomatous Polyposis (FAP) and MUTYH-associated polyposis (MAP) are rare, inherited genetic conditions which predispose to a very high risk of bowel cancer. Patients develop multiple adenomatous polyps. These are small growths on the inner lining of the colon (large intestine), and other areas of the intestinal tract.
FAP and MAP are inherited conditions that can lead to the formation of hundreds to thousands of colorectal polyps (image from Guts UK Charity)
Polyps can acquire genetic mutations that disrupt the functioning of the normal cell machinery and cause them to grow quickly, in a dysregulated manner. These polyps are on their way to becoming malignant.
Colorectal cancer progression (image from Guts UK Charity)
The average age for polyps to develop in patients with FAP is the mid-teens, with multiple polyps developing by the age of 35. MAP may be less severe than FAP with fewer polyps developing and later. The diagnosis is made by analysing the genetic code of the patients to look for specific mutations in the DNA that indicate why the instructions for normal cell growth have been corrupted.
This is followed by regular endoscopic examination of the upper intestines Endoscopy involves the insertion of a long, thin, flexible tube that has a tiny video camera at the end so that clinicians can closely observe the lining of the intestine as the tube is fed through. Treatment is by preventative colectomy (removal of some, or all the colon). Further surgery may be required if polyps form in the duodenum (duodenectomy). Very little is known about the causes of duodenal polyps and how this differs from colorectal disease in FAP and MAP. Research into this area is a high priority as there are high economic and quality of life costs associated with both diseases.
The gastro-intestinal tract (image from University of Missouri Health Care)
The Inherited Tumour Syndromes Research (ITSR) group has been developing 3D organoid cell models to represent duodenal malignancy in FAP and MAP patients. In a joint project with Cellesce (now part of Molecular Devices) and Dr. Laura Thomas (now at Swansea University) these models were further developed for use in an industrial environment, to facilitate drug discovery.
Organoids are 3D cell structures that are miniaturised versions of the tissue from which they originated. Organoids are used as representative models for research into the causes and effects of diseases and as a human-relevant platform for pre-clinical testing of potential treatments.
During the study, intestinal organoids were derived and expanded from intestine biopsy material from FAP and MAP patients, to replicate the biology and appearance of duodenal adenomas or of normal tissue (depending on where the biopsy was taken from) This included matched pairs of diseased and healthy 3D organoid lines from the same patients, for comparison. These lines are being used to facilitate further research into FAP and MAP, including drug discovery.
Duodenal adenoma organoids derived from biopsy tissue from a FAP patient
Compressed 3D image projection of a duodenal adenoma FAP organoid taken using a Zeiss 880 LSM microscope by the ITSR group. The blue stain identifies DNA in individual cells. The red stain is a marker for cytokeratin, a protein which is specifically found in the lining of the stomach and intestine. The organoid (“mini-guts”) are spheroidal in shape with a hollow interior (equivalent to the lumen of the intestine).
Drug Treatment
The ideal treatment for FAP and MAP patients would be to correct or neutralise the effects of the faulty instructions in these patients. This would prevent, or at least delay the growth of polyps and therefore disease progression and cause no unwanted side-effects. To date, no suitable drugs have been discovered that fulfil these needs.
Work is ongoing in several pharmaceutical companies to identify and develop completely new treatments and also to explore the use of existing drugs for the novel purpose of treating FAP and MAP.Since the drugs have already been approved for clinical use , the development costs and time taken to reach the patient aresignificantly reduced.
An example of a repurposed drug is guselkumab (Tremfya), that is used in the treatment of plaque psoriasis. It works by blocking inflammatory and immune responses. Janssen Pharmaceuticals (part of Johnson and Johnson) are performing clinical trials using this drug to treat FAP patients.
Additional clinical trials involve icosapent ethyl, originally used to prevent heart attacks (GLW Pharma), sirolimus (Emtora Biosciences), used after renal transplants to prevent rejection of the new kidney and the drugs chosen for the study below.
Pilot drug-treatment study
(Samadder NJ, et al Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis: A Randomized Clinical Trial. JAMA. 2016 Mar 22-29;315(12):1266-75. doi: 10.1001/jama.2016.2522. PMID: 27002448; PMCID: PMC5003411.)
Sulindac (Merck) : a non-steroidal anti-inflammatory
Erlotinib (Astellas Pharma U.S.) : a tyrosine kinase inhibitor that slows the growth of cancer cells with specific proteins (“EGFR”) on their cell surface.
To show if the effect of these drugs on 3D organoids mirrors the patient response, duodenal adenoma and the corresponding normal 3D organoid lines will be treated with Sulindac and Erlotinib alone and in combination. If successful, this will demonstrate that 3D duodenal adenoma and normal organoids derived from FAP/MAP patients are a suitable platform on which to test novel compounds and drug combinations for patients with these conditions. Findings from such studies may also be relevant to sporadic intestinal cancer therapy.
At Molecular Devices, we have scaled up the expansion of FAP/MAP 3D organoid lines with our 3D Ready™ Organoid Expansion Service. Quality-controlled organoids are manufactured at scale for high-throughput screening, leveraging proprietary bioreactor and bioprocess technology to produce reliable and predictive PDOs. These large numbers are critical to allow organoids to be more widely used in innovative research and high-throughput screens by pharmaceutical companies to facilitate drug discovery and development. Speak to an expert to learn more about our assay ready organoids.
Acknowledgements:
The charity Bowel Cancer West supported the initial work to derive and culture FAP and MAP 3D organoid models. Further development of the models was jointly supported by Cellesce and the Clinical Innovation Accelerator through Accelerate, a programme part-funded by the European Regional Development Fund.
None of the work on the ITSR project to derive, culture, expand and test FAP and MAP organoid lines could have taken place without the support and hard work of administrative, research and clinical staff in NHS hospitals, Cardiff University, Wales Gene Park, Wales Cancer BioBank and Cellesce. Neither would it have been possible without the generous donation of biopsy tissue from patients with FAP and MAP, for which we extend our thanks.