TCTP as therapeutic target in cancers
CANCER TREATMENT REVIEWS
2014; 40 (6): 760-769
Hsp27 as a Therapeutic Target in Cancers
CURRENT DRUG TARGETS
2014; 15 (4): 423-431
The translationally controlled tumor protein (TCTP) is a highly conserved protein present in eukaryotic organisms. This protein, located both in the cytoplasmic and the nucleus, is expressed in various tissues and is regulated in response to a wide range of extracellular stimuli. TCTP interacts with itself and other protein including MCL1 and p53. TCTP has been shown to play an important role in physiological events, such as cell proliferation, cell death and immune responses but also in stress response and tumor reversion. Moreover, TCTP expression is associated with malignancy and chemoresistance. In this review, we will evaluate pathways regulated by TCTP and current inhibitory strategy to target TCTP in cancerous diseases.
View details for DOI 10.1016/j.ctrv.2014.02.007
View details for Web of Science ID 000336825800009
View details for PubMedID 24650927
Targeting TCTP as a New Therapeutic Strategy in Castration-resistant Prostate Cancer
2012; 20 (12): 2244-2256
Heat shock protein 27 (Hsp27), induced by heat shock, environmental and pathophysiological stressors, is a multidimensional protein that acts as a protein chaperone and an antioxidant. This protein plays a major role in the inhibition of apoptosis and actin cytoskeletal remodeling. This stress-activated protein is up-regulated in many cancers and is associated with poor prognosis as well as treatment resistance by protecting cells from therapeutic agent that normally induces apoptosis. This review highlights the most recent findings and role of Hsp27 in cancer and the different strategies to target and inhibit Hsp27 for clinical purposes.
View details for Web of Science ID 000334351300004
View details for PubMedID 24138636
TP53INP1 as new therapeutic target in castration-resistant prostate cancer
2012; 72 (12): 1286-1294
Heat shock protein 27 (Hsp27) is highly overexpressed in castration-resistant prostate cancer (CRPC) and an antisense inhibitor (OGX-427) is currently in phase II clinical trials. In order to understand mechanisms of action of Hsp27 and find new therapeutic targets specific of CRPC, we screened for Hsp27 client proteins. Here, we report that translationally controlled tumor protein (TCTP) is a new Hsp27 client protein involved in Hsp27 cytoprotection. We found that TCTP expression is absent or weak in normal prostate cells, moderately expressed in 18.5% of treatment naive PC, and becomes uniformly and strongly expressed in 75% of CRPC. To define TCTP function, we developed and worldwide patented a TCTP antisense oligonucleotide (ASO). Interestingly, we found that CRPC progression correlates with TCTP overexpression and loss of P53. TCTP knockdown restored P53 expression and function, suggesting that castration-sensitivity is directly linked to P53 expression. Collectively, these findings provide a new Hsp27 cytoprotection mechanism in CRPC, and preclinical proof-of-concept that combining ASO-mediated TCTP knockdown with castration and/or docetaxel therapy could serve as a novel strategy to treat CRPC, with no or little toxicity for normal prostate cells.
View details for DOI 10.1038/mt.2012.155
View details for Web of Science ID 000311946700008
View details for PubMedID 22893039
OGX-427 inhibits tumor progression and enhances gemcitabine chemotherapy in pancreatic cancer
CELL DEATH & DISEASE
Prostate cancer (PC) is one of the most common malignancies in industrialized countries, and the second leading cause of cancer-related death in the United States. We recently showed that over-expression of tumor protein 53-induced nuclear protein 1 (TP53INP1), a cell stress response protein, is a worse prognostic factor in PC, particularly predictive of biological cancer relapse. Moreover, treatment of castration-sensitive (CS) LNCaP tumor cells with a TP53INP1 antisense oligonucleotide (TP53INP1 ASO) inhibits proliferation and induces apoptosis. The aim of this study was to investigate variations of TP53INP1 expression in PC during androgen withdrawal therapy and in castration-resistant prostate cancer (CRPC).Quantitative measurements of immunohistochemical expression of TP53INP1 using high-throughput densitometry, assessed on digitized microscopic tissue micro-array images were correlated with hormone therapy (HT) status in human PC. Northern blot analysis of TP53INP1 after castration was performed in LNCaP xenograft. Treatment of CR C4-2 tumor cells in vitro with TP53INP1 ASO was analyzed. We also analyzed the effect of TP53INP1 ASO treatment in vivo on tumor xenograft growth.TP53INP1 protein expression decreases during HT and increases after HT in human CRPC. TP53INP1 mRNA increases significantly in CR tumors of LNCaP xenograft. Moreover, treatment of CR C4-2 cells with TP53INP1 ASO downregulates TP53INP1 protein level, inhibits proliferation, and induces apoptosis. Finally, in vivo, TP53INP1 ASO treatment significantly inhibits the tumoral progression of CR C4-2 xenograft and enhances docetaxel cytotoxicity.These results suggest that TP53INP1 could be considered as a relevant-specific target for molecular therapy of CRPC.
View details for DOI 10.1002/pros.22477
View details for Web of Science ID 000306845100002
View details for PubMedID 22213058
Heat shock protein 27 confers resistance to androgen ablation and chemotherapy in prostate cancer cells through eIF4E
2010; 29 (13): 1883-1896
Despite many advances in oncology, almost all patients with pancreatic cancer (PC) die of the disease. Molecularly targeted agents are offering hope for their potential role in helping translate the improved activity of combination chemotherapy into improved survival. Heat shock protein 27 (Hsp27) is a chaperone implicated in several pathological processes such as cancer. Further, Hsp27 expression becomes highly upregulated in cancer cells after chemotherapy. Recently, a modified antisense oligonucleotide that is complementary to Hsp27 (OGX-427) has been developed, which inhibits Hsp27 expression and enhances drug efficacy in cancer xenograft models. Phase II clinical trials using OGX-427 in different cancers like breast, ovarian, bladder, prostate and lung are in progress in the United States and Canada. In this study, we demonstrate using TMA of 181 patients that Hsp27 expression and phosphorylation levels increase in moderately differentiated tumors to become uniformly highly expressed in metastatic samples. Using MiaPaCa-2 cells grown both in vitro and xenografted in mice, we demonstrate that OGX-427 inhibits proliferation, induces apoptosis and also enhances gemcitabine chemosensitivity via a mechanism involving the eukaryotic translation initiation factor 4E. Collectively, these findings suggest that the combination of Hsp27 knockdown with OGX-427 and chemotherapeutic agents such as gemcitabine can be a novel strategy to inhibit the progression of pancreas cancer.
View details for DOI 10.1038/cddis.2011.104
View details for Web of Science ID 000296587500010
View details for PubMedID 22012255
One strategy to improve therapies in advanced prostate cancer (PC) involves targeting genes that are activated by androgen withdrawal to delay the emergence of the androgen-independent (AI) phenotype. Heat shock protein 27 (Hsp27) expression becomes highly upregulated in PC cells after androgen withdrawal or chemotherapy, in which it functions as a cytoprotective chaperone to confer broad-spectrum treatment resistance. The purpose of this study is to elucidate anti-apoptotic pathways regulated by Hsp27 that are activated during PC progression. Using two-hybrid experiment, we found that Hsp27 was having a major role in the protein translational initiation process. Furthermore, using complementary DNA (cDNA) microarray analysis, 4E binding protein 1 was identified as being proportionately and highly regulated by Hsp27. These data led us to analyze the protein synthesis initiation pathway, which is a prerequisite for cell growth and proliferation. Using northern and western blot analysis, we found that Hsp27 downregulation decreased eukaryotic translation initiation factor 4E (eIF4E) expression at the protein, but not mRNA, level. The cytoprotection afforded by Hsp27 overexpression was attenuated by eIF4E knockdown using specific eIF4E short interfering RNA (siRNA). Co-immunoprecipitation and co-immunofluorescence confirmed that Hsp27 colocalizes and interacts directly with eIF4E. Hsp27-eIF4E interaction decreases eIF4E ubiquitination and proteasomal degradation. By chaperoning eIF4E, Hsp27 seems to protect the protein synthesis initiation process to enhance cell survival during cell stress induced by castration or chemotherapy. Forced overexpression of eIF4E induces resistance to androgen-withdrawal and paclitaxel treatment in the prostate LNCaP cells in vitro. These findings identify Hsp27 as a modulator of eIF4E and establish a potential mechanism for the eIF4E-regulated apoptosis after androgen ablation and chemotherapy. Targeting Hsp27-eIF4E interaction may serve as a therapeutic target in advanced PC.
View details for DOI 10.1038/onc.2009.479
View details for Web of Science ID 000276199600002
View details for PubMedID 20101233