Abstract: The invention relates to methods of treating cancer, particular cancers which have developed a resistance to chemotherapeutics. Particularly, the invention relates to a method of treating cancer in an individual who has not responded, or no longer responds, to chemotherapy, the method comprising providing an individual who has not responded, or no longer responds, to a chemotherapeutic agent; providing in the individual a whole antibody or a fragment thereof including a variable domain for binding to a P2X7 receptor that is expressed by the individual; wherein the P2X7 receptor has an impaired response to ATP such that it is unable to form an apoptotic pore under normal physiological conditions, thereby treating cancer in the individual.

Abstract: The invention provides a modified tachykinin receptor in which the three amino acids of the DRY sequence that occurs adjacent to the junction of the TM3 domain with intracellular loop 2 are replaced with amino acids whose side chains are neither lipophilic nor contain charged groups. The receptor exhibits similar ligand binding characteristics to the wild type receptor but is incapable or substantially incapable of initiating an endogenous signal. Thus the ligand exhibits no or substantially no intra-cellular coupling of the receptor to the G protein, whereby there is substantially no transduction of ligand binding signals to the cell, The invention also includes fragments of the receptor containing the modified DRY sequence, and polynucleotides that encode the modified receptor as aforesaid. Therapeutic and diagnostic uses for the receptor are disclosed.