Stem cells engineered to express telomerase
With the isolation of the gene encoding the catalytic subunit telomerase, scientists could now transform cells with an expression vector comprising sequences encoding telomerase. In turn, they expected that the transformed cells, which expressed increased levels of telomerase, would be immortalized or at least have a longer lifespan. What a boon it would be for the numerous cell types that are difficult to grow in vitro.
Given that human telomerase was cloned in 1997, it is a bit surprising (to the author) that there don’t appear to be any issued U.S. patents in the field of transformed stem cells. Moreover, there aren’t a huge number of pending patents. Maybe some of the paucity can be explained by the huge number of U.S. patents issued on aspects of stem cells. For example, the web site www.stemcellpatents.com lists over 1000 granted U.S. patents. Within the “minefield” of stem cell-related patents you may well find at least a few patents with claims that would dominate a claim to stem cells (of any sort) that are transformed with a sequence encoding telomerase. For instance, the WARF patents, referred to above, claim a “purified preparation of pluripotent human embryonic stem cells” albeit with specific characteristics. U.S. Patent 4,714,680 (now expired) claimed “A suspension of human cells comprising pluripotent lympho-hematopoietic stem cells substantially free of mature lymphoid and myeloid cells.”
Against this backdrop, we present 8 patent applications and 1 patent directed to compositions and methods for inhibiting cell senescence or increasing proliferative potential of cells and for isolating stem cells. The inventions disclosed in each of these applications uses telomerase in achieving these results.