Mislocalization of death receptors correlates with cellular resistance to their cognate ligands in human breast cancer cells

Abstract

ABSTRACT:Multiple clinical trials are ongoing to evaluate the potential antitumor activity of human TNF variants, Fas ligand (FasL), TNF-related apoptosis inducing ligand (TRAIL) and its agonistic antibodies. These drug products act through the death receptors (DRs) TNF receptor 1 (TNFR1), Fas/CD95, DR4 (TRAIL-R1) and/or DR5 (TRAIL-R2), respectively. Therefore, characterization of the level and localization of DR expression in cancer cells is important for DR-targeted therapy. In this study, we examined the subcellular distribution of the four DRs in a panel of 10 human breast cancer cell lines by western blots and flow cytometry and 50 human breast tumors by immunohistochemistry. Despite their total protein expressions, the DRs were found to be absent on the surface of some cell lines. Consistent with this result, all four DRs were found to be mostly expressed in the cytoplasm and/or the nucleus of primary breast tumors (n=50). We further determined the growth inhibition activity (GI50) of the death ligands, recombinant human TNFα, FasL and TRAIL, and found a correlation with the subcellular localization of the corresponding DRs. These results demonstrate an aberrant expression of the death receptors in breast cancer cells, and suggest that the lack of surface DRs appears to be predictive of tumor resistance to DR-targeted therapies.

Loss of TRAIL-Receptors Is a Recurrent Feature in Pancreatic Cancer and Determines the Prognosis of Patients with No Nodal Metastasis after Surgery

“…Similar results were obtained by stratifying patients according to TRAIL-receptors intensity staining scores. However, membrane staining for TRAIL-R2 was associated with a better prognosis in a subgroup of patients without nodal metastases at the time of surgery, which is consistent with recent evidence that the fraction of membrane-bound receptors determines their functional status [11], [31] and plays a major prognostic role in patients with hepatocellular carcinoma [8].…”

“…the fraction of tumors exhibiting TRAIL-receptors staining on cell membranes in our study. We found that 56% of tumor samples displayed no membrane staining for TRAIL-R1 and 19% for TRAIL-R2 with the extent of membrane staining varying inversely with the cytoplasmatic staining, suggesting that internalization of TRAIL-receptors could represent a mechanism for the loss of functional TRAIL receptors as a distinctive feature of pancreatic cancer cells, a hypothesis recently corroborated by other studies in vitro [11], [31].…”

Silencing the epigenetic silencer KDM4A for TRAIL and DR5 simultaneous induction and antitumor therapy

“…The cell surface expression of DR4 or DR5 is a key determinant of tumor sensitivity to the TRAIL-DR targeted therapies. 44 To examine whether KDM4A inhibitor C-4 induced DR5 expression at cell surface, we immunoprecipitated the receptors from the cell surface after cells were treated with C-4. We used an immunoprecipitation method 45 instead of flow cytometry because of the auto-fluorescence activity of C-4.…”

Circulating Tumor Cells Develop Resistance to TRAIL-Induced Apoptosis through Autophagic Removal of Death Receptor 5: Evidence from an <em>In Vitro</em> Model

“…DR5 mRNA level was not affected; thus, the loss of DR5 protein expression could be attributed to autolysosomal degradation. As shown in monolayer cancer cells [23,37], a deficiency in the cell surface DR5 is correlated with resistance to TRAIL induced apoptosis.…”

“…We have previously shown that breast cancer cellular sensitivity to TNF death ligands is correlated with the corresponding death receptor (DR) expression on the plasma membrane [23,37]. To test this possibility in the non-adherent cultured cells, we performed flow cytometry analysis using antibodies specific to DR4, DR5, Fas, and TNFR1 respectively.…”