‘Scope for innovation in genetic medicine’

There is a tremendous opportunity in genetic medicine for innovation and for new players to make significant contributions, because it is still experimental, noted biologist and Nobel Laureate Dr David Baltimore said yesterday.
“Today, it is mainly the province of biotechnology companies and universities, not big pharmaceutical companies,” he observed in a keynote presentation at the Qatar International Conference on Stem Cell Science and Policy 2012.
There are new genetic tools available – though they are still experimental - to treat diseases which involve adding, subtracting or modifying genes in the cells of the body.
“However, they are powerful tools and I am confident they will be an important part of the medicine of the future,” he said.
Speaking on ‘The hematopoietic stem cell (HSC) as a target for therapy against cancer and Aids,’ Dr Baltimore explained that HSCs are one of the few cell types routinely used for bone marrow transplant.
The HSCs are easily accessible, retroviruses can be used to carry genes into these stem cells, the genes are then expressed in all of cells that derive from the HSC and can correct inherited defects and bring genes that perform therapy under a programme called engineering immunity.
“Though the human immune system is a wondrous creation of evolution yet it is not without certain limitations. One, in particular, is its poor ability to stop the growth of cancer cells– another is its hosting of HIV.
“In the case of cancer, the machinery of immunity can attack cancers but it rarely attacks with the necessary power. For HIV, the ability of the virus to use the CD4 and CCR5 proteins as receptors means that CD4 cells are the major cell type in which the virus grows.
“We have been trying to supply genes to the immune system by gene transfer methods that would improve its ability to block cancer and block infection of CD4 cells by HIV.
“For cancer, we have focused on T cell receptor genes. For HIV, we have used a small interfering ribonucleic acid (siRNA) targeted to CCR5. We have been quite successful in mice with both strategies and are now moving to humans.
“In both cases, our experiments with mice have focused on putting genes into HSCs as, once these cells are altered, they provide modified blood cells to the body for life.
“In our human cancer trials we first used peripheral T cells for modification with dramatic effect but it has been transient.
“We are now moving to stem cells. For the siRNA against CCR5, we plan to initiate trials within six months using autologous, gene-modified stem cells,” he added.
The ensuing panel discussion on ‘Opportunities and challenges for stem cell research,’ saw Prof Irving Weissman (Stanford Institute for Stem Cell Biology and Regenerative Medicine) cautioning against ‘phoney organisations engaged in stem cell therapy.’
Prof Juan Carlos Izpisua Belmonte (Salk Institute for Biological Studies, US) stated that stem cells derived from umbilical cord blood should be considered as one of the key cells for use in regenerative medicine.
The session also featured Dr Alan Trounson (California Institute of Regenerative Medicine), Prof Roger Pedersen (The Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge), Dr Lawrence Corey (University of Washington) and with Dr Richard Klausner (managing partner of biotechnology venture capital firm The Column Group) as moderator.
Earlier, Ambassador Edward P Djerejian (founding director, James A Baker III Institute for Public Policy, Rice University, Houston, Texas, US) spoke about the collaboration with Qatar Foundation on stem cell research.

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‘Scope for innovation in genetic medicine’