Pursuing new ways to cure cancer

Pioneering Harvard University scientist and University of Cape Town (UCT) alumnus Professor Frank Slack has returned to his academic roots to share groundbreaking research which holds the promise of new ways to cure cancer and other illnesses.

Slack presented a lecture titled “Our smallest genes and cancer – prospects for personalised medicine” on 18 October, as part of the Faculty of Science’s Distinguished Alumni Lecture Series.

He has been at the forefront of the discovery of a new class of non-coding genes known as microRNAs, which play a pivotal role in controlling important biological processes such as stem cell development, ageing and the progression of cancer.

Students and academics spanning three generations attended the lecture and were clearly inspired by the pivotal research outlined by Slack, the director of the Harvard Medical School Initiative for RNA Medicine. He graduated from UCT in 1987 with a BSc(Hons) in microbiology and biochemistry, before furthering his studies in the United States.

Slack highlighted the magnitude of cancer, which has overtaken heart disease to become the top killer of Americans under 85 and is on the rise globally. He said half of men and a third of women will get cancer in their lifetime.

“Cancer is common and needs better therapies, as it kills most of the time.”

He described cancer as a collection of 200 diseases, from lung and breast cancers to blood cancers.

“Cancer is a disease of our own cells, but also our own genes. When cells become cancerous they change their form and become resistant to drugs. They live much longer and divide more frequently. Scientists have been trying to work out how to kill these cells and, at the same time, leave the normal cells alone.”

“With personalised medicine, it won’t be too long in the future where every cancer patient will have their genome sequenced. Based on that, we can decide which drugs a patient should be taking.”

Personalised medicine

Slack, who is known particularly for his work on lung cancer, which is resistant to almost every kind of drug, has been exploring personalised medicine in a bid to find targeted therapies for patients.

A surge of interest in genomics is driving the field of personalised medicine, in which therapeutic decisions can be based on the genome of the patient.

He said cancer patients were offering their tumours to science so that they can be sequenced.

“With personalised medicine, it won’t be too long in the future where every cancer patient will have their genome sequenced. Based on that, we can decide which drugs a patient should be taking.”

Although personalised medicine is showing some success with targeted therapies, Slack cautioned that resistance emerges in some patients.

Together with his team at Harvard, he is passionate about bringing scientists and clinical trials together in this relatively new field, which holds so much promise.

He described his groundbreaking work in microRNAs – the smallest known RNAs in our cells – which can be used as potential therapies in cancer. While proteins have traditionally been thought of as the building blocks and enzymes responsible for life, microRNAs are emerging as pivotal.

“MicroRNAs are tiny regulators of other genes, including cancer genes, and are altered in cancer. They not only form part of the cancer process, but can be useful in diagnosing the cancer.

“We have ways to manipulate microRNAs and use them as therapeutics. We can inject them into people and they can work.”

Therapies of the future

According to Slack, the first clinical trials involving microRNAs are under way and could provide cancer therapies in the future.

He described trials involving microRNA on a mouse, and showed how a tumour had shrunk from the size of a golf ball to a pinhead after treatment. Another trial had managed to reduce lymphoma.

“Without these kinds of studies, human trials never start. It’s provided some kind of proof of concept that this idea will work.”

The number of clinical trials involving non-coding RNAs is on the rise, Slack said. For example, the Harvard scientists are working on a clinical trial involving the examination of four different patients with pancreatic cancer.

“We hope the clinical trials will show efficacy in humans. It also brings hope for lymphoma patients for which drugs generally fail. We hope this new understanding of genomes will help us tackle disease and cancers.

“MicroRNA represents a new genetic universe to explore. It’s almost like giving Galileo a Hubble telescope. It’s opened our eyes. We can see things we didn’t appreciate before. It’s an extremely exciting time.”

It could also hold hope for people battling disease across the world.

“We now have potentially hundreds of thousands of new targets for therapy and biomarkers of disease. Tools used in this research could also be used to go after other diseases, such as infectious diseases, diabetes, cardiovascular disease and Alzheimer’s.”

Distinguished graduates

Dean of the Science faculty Professor Susan Bourne said the lecture series was an opportunity to celebrate the achievement of graduates who had gone on to do distinguished research in other parts of the world, and who carry the name and the reputation of the university with them. She said Slack perfectly encapsulated this.

The faculty’s Deputy Dean, Professor Nicola Illing, welcomed Slack back to his alma mater and reminded him that they had shared a bench together in the laboratory while they were both students at UCT.

Slack went on to study and do research at Stanford and Yale universities before moving on to Harvard. He credits UCT for his formative years and showed a slide of himself with fellow students in the laboratory on upper campus 31 years ago.

“We were doing state-of-the-art molecular biology back then. It was a fun time to be a molecular biologist.”

But while fun, it was also a year of plenty of hard work.

Addressing the students in the audience, he said: “Your honours year is the hardest year you will ever have.

“I have been to the top institutions, but the workload here was incredible. I learnt so much. When I started my PhD in the US, I was extremely well prepared. My time at UCT had stood me in good stead and I thank my professors for the great start I got in academic life.”