Receptor-mediated uptake of an extracellular Bcl-xL fusion protein inhibits apoptosis

Abstract

Apoptosis-modifying fusion polypeptides, and the corresponding nucleic acid molecules, are disclosed. Pharmaceutical compositions comprising these polypeptides, and the use of these polypeptides to modify apoptosis are also provided.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001] This is a divisional of U.S. application Ser. No. 09 / 639,245, filed Aug. 15, 2000, which claims the benefit of U.S. Provisional Application No. 60 / 149,220, filed Aug. 16, 1999, both of which are incorporated herein by reference in their entirety.FIELD[0002] This invention relates to modification of the apoptotic response of target cells, for instance target cells in a subject. More specifically, it relates to apoptosis-modifying fusion proteins with at least two domains, one of which targets the fusion protein to a target cell, and another of which modifies an apoptotic response of the target cell.[0003] Tissue and cell homeostasis in multicellular organisms is largely influenced by apoptosis, the phenomenon of programmed cell death by which an intra- or extra-cellular trigger causes a cell to activate a biochemical "suicide" pathway. Morphological indicia of apoptosis include membrane blebbing, chromatin condensation and fragmentation,...

AI Technical Summary

Benefits of technology

The patent describes a method of creating fusion proteins that can be used to modify the process of cell death (apoptosis) in specific cells. These fusion proteins are made by combining a protein from the Bcl-2 family with a cell-binding protein from a bacterial toxin. These fusion proteins can be delivered effectively throughout the body and targeted to specific cells, making them useful for treating various disease and injury conditions. They can either inhibit or enhance the apoptotic response, depending on the disease or injury being treated. The fusion proteins can be made by recombinant DNA technology and are effective in treating various disease and injury conditions.

Problems solved by technology

In spite of much study, the molecular mechanisms of apoptosis are not fully elucidated.

Treatment with standard apoptosis inhibitory molecules, for instance peptide-type caspase inhibitors (e.g., DEVD-type), though useful for laboratory experiments where microinjection can be employed, has proven unsatisfactory for clinical work due to low membrane permeability of these inhibitors.

First, transfection is usually not cell-specific, and thus may disrupt apoptotic processes non-specifically in all cells.

Second, transfection tends to provide long term alterations in the apoptotic process, in that once a transgene is integrated and functional in the genome of target cells, it may be difficult to turn off.

Promising though they might have seemed, these and similar hybrid immunotoxins have proven to be substantially less effective at targeted cell death than the toxins from which they were generated.

In addition, in vivo results have been particularly poor using such hybrid constructs (Fulton et al., Fed. Proc. 461:1507, 1987).

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