BACKGROUND: Induction of molecular chaperone Grp78 (78-kDa glucose-regulated protein) occurs in stress conditions that often characterize tumor microenvironments. We investigated the role of Grp78 in prostate cancer progression and the development of castration resistance, where cancer cells continue to survive despite the stress of an androgen-starved environment. EXPERIMENTAL DESIGN: Immunohistochemistry was done to examine Grp78 expression in 219 prostate cancers from patients with pathologic stage T3N0M0 disease [androgen ablation naive (untreated) and androgen ablation exposed (treated)] and castration-resistant prostate cancer. Classification of tumors was based on intensity of Grp78 cytoplasmic immunoreactivity and percentage of immunoreactive tumor cells. The associations of Grp78 expression with prostate cancer recurrence (clinical and/or serum prostate-specific antigen) and survival were examined in the untreated stage T3N0M0 group. Grp78 expression was also analyzed in the androgen-dependent LNCaP and castration-resistant C42B cell lines. RESULTS: The percentage of tumor cells expressing Grp78 was strongly associated with castration-resistant status (P = 0.005). Increased Grp78 expression was consistently associated with greater risk of prostate cancer recurrence and worse overall survival in patients who had not undergone prior hormonal manipulation. Grp78 expression was also increased in the castration-resistant LNCaP-derived cell line C42B and in LNCaP cells grown in androgen-deprived conditions compared with LNCaP cells grown in androgen-rich media. CONCLUSION: Our findings show that up-regulation of Grp78 is associated with the development of castration resistance, possibly in part by augmenting cell survival as previously suggested, and may serve as an important prognostic indicator of recurrence in a subset of patients with T3N0M0 disease.
BACKGROUND: Induction of molecular chaperone Grp78 (78-kDa glucose-regulated protein) occurs in stress conditions that often characterize tumor microenvironments. We investigated the role of Grp78 in prostate cancer progression and the development of castration resistance, where cancer cells continue to survive despite the stress of an androgen-starved environment. EXPERIMENTAL DESIGN: Immunohistochemistry was done to examine Grp78 expression in 219 prostate cancers from patients with pathologic stage T3N0M0 disease [androgen ablation naive (untreated) and androgen ablation exposed (treated)] and castration-resistant prostate cancer. Classification of tumors was based on intensity of Grp78 cytoplasmic immunoreactivity and percentage of immunoreactive tumor cells. The associations of Grp78 expression with prostate cancer recurrence (clinical and/or serum prostate-specific antigen) and survival were examined in the untreated stage T3N0M0 group. Grp78 expression was also analyzed in the androgen-dependent LNCaP and castration-resistant C42B cell lines. RESULTS: The percentage of tumor cells expressing Grp78 was strongly associated with castration-resistant status (P = 0.005). Increased Grp78 expression was consistently associated with greater risk of prostate cancer recurrence and worse overall survival in patients who had not undergone prior hormonal manipulation. Grp78 expression was also increased in the castration-resistant LNCaP-derived cell line C42B and in LNCaP cells grown in androgen-deprived conditions compared with LNCaP cells grown in androgen-rich media. CONCLUSION: Our findings show that up-regulation of Grp78 is associated with the development of castration resistance, possibly in part by augmenting cell survival as previously suggested, and may serve as an important prognostic indicator of recurrence in a subset of patients with T3N0M0 disease.
Authors: Teneille Walker; Clint Mitchell; Margaret A Park; Adly Yacoub; Mohamed Rahmani; Dieter Häussinger; Roland Reinehr; Christina Voelkel-Johnson; Paul B Fisher; Steven Grant; Paul Dent Journal: Mol Cancer Ther Date: 2010-05-04 Impact factor: 6.261
Authors: Emma Pewsey; Christine Bruce; A Stephen Georgiou; Mark Jones; Duncan Baker; Saw Yen Ow; Phillip C Wright; Christel K Freberg; Philippe Collas; Alireza Fazeli Journal: Mol Cell Proteomics Date: 2009-02-27 Impact factor: 5.911
Authors: Young Ah Goo; Alvin Y Liu; Soyoung Ryu; Scott A Shaffer; Lars Malmström; Laura Page; Liem T Nguyen; Catalin E Doneanu; David R Goodlett Journal: Prostate Date: 2009-01-01 Impact factor: 4.104
Authors: Jami Mandelin; Marina Cardó-Vila; Wouter H P Driessen; Paul Mathew; Nora M Navone; Sue-Hwa Lin; Christopher J Logothetis; Anna Cecilia Rietz; Andrey S Dobroff; Bettina Proneth; Richard L Sidman; Renata Pasqualini; Wadih Arap Journal: Proc Natl Acad Sci U S A Date: 2015-03-11 Impact factor: 11.205