Targeting death receptors in bladder, prostate and renal cancer.
OBJECTIVE
We describe key components of normal and aberrant death receptor pathways, the association of these abnormalities with tumorigenesis in bladder, prostate and renal cancer, and their potential application in novel therapeutic strategies targeted toward patients with cancer.


METHODS
A MEDLINE literature search of the key words death receptors, TRAIL (tumor necrosis factor related apoptosis inducing ligand), FAS, bladder, prostate, renal and cancer was done to obtain information for review. A brief overview of the TRAIL and FAS death receptor pathways, and their relationship to apoptosis is described. Mechanisms that lead to nonfunction of these pathways and how they may contribute to tumorigenesis are linked. Current efforts to target death receptor pathways as a therapeutic strategy are highlighted.


RESULTS
Activation of tumor cell expressing death receptors by cytotoxic immune cells is the main mechanism by which the immune system eliminates malignant cells. Death receptor triggering induces a caspase cascade, leading to tumor cell apoptosis. Receptor gene mutation or hypermethylation, decoy receptor or splice variant over expression, and downstream inhibitor interference are examples of the ways that normal pathway functioning is lost in cancers of the bladder and prostate. Targeting death receptors directly through synthetic ligand administration and blocking downstream inhibitor molecules with siRNA or antisense oligonucleotides represent novel therapeutic strategies under development.


CONCLUSIONS
Research into the death receptor pathways has demonstrated the key role that pathway aberrations have in the initiation and progression of malignancies of the bladder, prostate and kidney. This new understanding has resulted in exciting approaches to restore the functionality of these pathways as a novel therapeutic strategy.
O'Kane
Hugh F
HF
Uro-oncology Group, Queen's University Belfast, Belfast, United Kingdom. hugh_o_kane@hotmail.com
Watson
Chris J
CJ
Johnston
Samuel R
SR
Petak
Istvan
I
Watson
R William G
RW
Williamson
Kate E
KE
D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007680:Kidney Neoplasms / Q000188:drug therapy / Q000209:etiology*; D008297:Male; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000209:etiology*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology*; D018124:Receptors, Tumor Necrosis Factor / Q000187:drug effects / Q000502:physiology*; D053323:Receptors, Tumor Necrosis Factor, Member 6b; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000502:physiology*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000209:etiology*
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D053323:Receptors, Tumor Necrosis Factor, Member 6b; D053221:TNF-Related Apoptosis-Inducing Ligand; C505911:TNFRSF6B protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha