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Zohar Y, Mabjeesh NJ. Targeting HIF-1 for prostate cancer: a synthesis of preclinical evidence. Expert Opin Ther Targets 2023; 27:715-731. [PMID: 37596912 DOI: 10.1080/14728222.2023.2248381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/20/2023] [Accepted: 08/10/2023] [Indexed: 08/21/2023]
Abstract
INTRODUCTION Hypoxia-inducible factor (HIF) mediates multiple intracellular processes that drive cellular metabolism and induce proliferation. Dysregulated HIF expression is associated with oncogenic cellular transformation. Moreover, high HIF levels correlate with tumor aggressiveness and chemoresistance, indicating the vital effect of HIF-1α on tumorigenicity. Currently, widespread in-vitro and in-vivo research is focusing on targeting HIF with drugs that have already been approved for use by the FDA, such as belzutifan, in renal cell carcinoma. HIF inhibition is mostly associated with tumor size reduction; however, drug toxicity remains a challenge. AREA COVERED In this review, we focus on the potential of targeting HIF in prostate cancer (PC) and summarize the scientific background of HIF activity in PC. This finding emphasizes the rationale for using HIF as a therapeutic target in this malignancy. We have listed known HIF inhibitors that are being investigated in preclinical studies and their potential as anticancer drugs for PC. EXPERT OPINION Although HIF-targeting agents have been investigated for over a decade, their use in therapy-resistant cancers remains relevant and should be explored further. In addition, the use of naturally occurring HIF inhibitors should be considered as an add-on therapy for the currently used regimens.
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Affiliation(s)
- Yarden Zohar
- Department of Urology, Health Sciences, Soroka University Medical Center, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Nicola J Mabjeesh
- Department of Urology, Health Sciences, Soroka University Medical Center, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
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Matsuda T, Miyata Y, Nakamura Y, Otsubo A, Mukae Y, Harada J, Mitsunari K, Matsuo T, Ohba K, Furusato B, Sakai H. Pathological significance and prognostic role of LATS2 in prostate cancer. Prostate 2021; 81:1252-1260. [PMID: 34492128 PMCID: PMC9290072 DOI: 10.1002/pros.24226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 11/11/2022]
Abstract
BACKGROUND Large tumor suppressor 2 (LATS2) is an important regulator of the Hippo pathway and it plays crucial roles in cell survival and behaviors. Herein, we evaluated the pathological roles of LATS2 in prostate cancer (PC), for which very little information is available. METHODS Cell proliferation, migration, and invasion in response to the siRNA-mediated knockdown (KD) LATS2 expression were evaluated in two PC cell lines (LNCaP and PC3). The expression of LATS2 in specimens from 204 PC patients was investigated immunohistochemically, and the relationships between its expression and clinicopathological features, proliferation index (PI; measured using an anti-KI-67 antibody), and biochemical recurrence (BCR) were investigated. RESULTS KD of LATS2 increased the growth, migration, and invasion in LNCaP cells and only increased migration in PC3 cells. The expression of LATS2 was negatively associated with the grade group, T, N, M stage, and PI. In addition, the expression of LATS2 was a useful predictor of the histological effects of neoadjuvant hormonal therapy and BCR-free survival periods. A multivariate analysis model including clinicopathological features showed that negative expression of LATS2 had a significantly higher risk of BCR (odds ratio = 2.95, P < 0.001). CONCLUSIONS LATS2 acts as a tumor suppressor in PC. LATS2 expression is a useful predictor for BCR. LATS2-related activities are possibly dependent on the androgen-dependency of PC cells. Therefore, we suggest that LATS2 could be a potential therapeutic target and a useful predictor for outcome in patients with PC.
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Affiliation(s)
- Tsuyoshi Matsuda
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Yasuyoshi Miyata
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Yuichiro Nakamura
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Asato Otsubo
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Yuta Mukae
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Junki Harada
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Kensuke Mitsunari
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Tomohiro Matsuo
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Kojiro Ohba
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
| | - Bungo Furusato
- Department of pathologyNagasaki University Graduate School of Biomedical ScienecesNagasakiJapan
| | - Hideki Sakai
- Department of UrologyNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
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Antonelli A, Palumbo C, Veccia A, Grisanti S, Triggiani L, Zamboni S, Furlan M, Simeone C, Magrini S, Berruti A. Biological effect of neoadjuvant androgen-deprivation therapy assessed on specimens from radical prostatectomy: a systematic review. MINERVA UROL NEFROL 2018; 70:370-379. [DOI: 10.23736/s0393-2249.18.03022-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Santa Mina D, Connor MK, Alibhai SMH, Toren P, Guglietti C, Matthew AG, Trachtenberg J, Ritvo P. Exercise effects on adipokines and the IGF axis in men with prostate cancer treated with androgen deprivation: A randomized study. Can Urol Assoc J 2013; 7:E692-8. [PMID: 24282459 DOI: 10.5489/cuaj.235] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Androgen deprivation therapy (ADT) has significant deleterious effects on body composition that may be accompanied by unfavourable changes in adipokine levels. While exercise has been shown to improve a number of side effects associated with ADT for prostate cancer, no studies have assessed the effect of exercise on adiponectin and leptin levels, which have been shown to alter the mitogenic environment. METHODS Twenty-six men with prostate cancer treated with ADT were randomized to home-based aerobic exercise training or resistance exercise training for 24 weeks. Adiponectin, leptin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3) were analyzed by ELISA (enzyme-linked immunosorbent assay), in addition to physical activity volume, peak aerobic capacity, and anthropometric measurements, at baseline, 3 months and 6 months. RESULTS Resistance exercise significantly reduced IGF-1 after 3 months (p = 0.019); however, this change was not maintained at 6 months. At 6 months, IGFBP-3 was significantly increased compared to baseline for the resistance training group (p = 0.044). In an exploratory analysis of all exercisers, favourable changes in body composition and aerobic fitness were correlated with favourable levels of leptin, and favourable leptin:adiponectin and IGF-1:IGFBP-3 ratios at 3 and 6 months. CONCLUSIONS Home-based exercise is correlated with positive changes in adipokine levels and the IGF-axis that may be related to healthy changes in physical fitness and body composition. While the improvements of adipokine markers appear to be more apparent with resistance training compared to aerobic exercise, these findings must be considered cautiously and require replication from larger randomized controlled trials to clarify the role of exercise on adipokines and IGF-axis proteins for men with prostate cancer.
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Affiliation(s)
- Daniel Santa Mina
- Princess Margaret Cancer Centre, Toronto, ON; ; York University, Toronto, ON; ; University of Guelph-Humber, Toronto, ON
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IGFBP-3 nuclear localization predicts human prostate cancer recurrence. Discov Oncol 2012; 4:12-23. [PMID: 23011725 DOI: 10.1007/s12672-012-0124-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 09/10/2012] [Indexed: 01/19/2023] Open
Abstract
Insulin-like growth factor binding protein-3 (IGFBP-3) is a pro-apoptotic, anti-metastasic, and anti-angiogenic protein. Low serum IGFBP-3 has been associated with risk of more aggressive prostate cancer (PCa). We investigated the impact of nuclear and cytoplasmic IGFBP-3 protein expression levels in PCa by examining their in situ expression across a wide spectrum of primary tumors by immunohistochemical analysis of tissue microarrays. Immunohistochemistry was performed on PCa microarrays constructed from 226 hormone naïve patients who underwent radical prostatectomy. Both cytoplasmic and nuclear IGFBP-3 expressions were scored in a semi-quantitative fashion using an integrated measure of intensity and positivity. The distribution of IGFBP-3 protein expression was examined across the spectrum of epithelial tissues, and its association with standard clinicopathological covariates and tumor recurrence was examined. There was a broad range of IGFBP-3 staining across all histologies examined. Tumor had higher IGFBP-3 cytoplasmic and nuclear staining than benign histologies. For IGFBP-3 nuclear staining, PCa was significantly different than benign prostatic hyperplasia, normal prostate, and prostate intraepithelial neoplasia. As both a continuous and dichotomized variable, higher nuclear IGFBP-3 expression had statistically significant associations with PCa recurrence. The cytoplasmic staining had no significance in any patient subgroup. In patients with low-grade cancer, IGFBP-3 nuclear positivity was a better predictor of recurrence than baseline PSA, tumor margin status, TNM tumor stage, or presence of capsular invasion. High nuclear IGFBP-3 is amongst the strongest predictors of cancer recurrence in patients with low-grade prostate cancers and may therefore play an important role in risk stratification.
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Gulzar ZG, McKenney JK, Brooks JD. Increased expression of NuSAP in recurrent prostate cancer is mediated by E2F1. Oncogene 2012; 32:70-7. [PMID: 22349817 PMCID: PMC3360134 DOI: 10.1038/onc.2012.27] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Increasing evidence suggests that prostate cancer is overdiagnosed and overtreated, and prognostic biomarkers would aid in treatment selection. To define prognostic biomarkers for aggressive prostate cancer, we carried out gene-expression profiling of 98 prostate tumors and 52 benign adjacent prostate tissue samples with detailed clinical annotation. We identified 28 transcripts significantly associated with recurrence after radical prostatectomy including NuSAP, a protein that binds DNA to the mitotic spindle. Elevated NuSAP transcript levels were associated with poor outcome in two independent prostate cancer gene-expression datasets. To characterize the role and regulation of NuSAP in prostate cancer, we studied the expression of NuSAP in the LNCaP and PC3 human prostate cancer cell lines. Posttranscriptional silencing of the NuSAP gene severely hampered the ability of PC3 to invade and proliferate in vitro. The promoter region of the NuSAP gene contains two CCAAT boxes and binding sites for E2F. Transient transfection of an E2F1 cDNA and 431 bp of the NuSAP promoter demonstrated E2F1 as an important regulator of expression. Deletion of the E2F-binding site at nucleotide -246 negated the effects of E2F1 on NuSAP expression. Electrophoretic mobility shift assays demonstrated that nuclear extracts of cells overexpressing E2F1 bound directly to the E2F-binding site in the NuSAP promoter region. Finally, immunohistochemistry showed a strong correlation between E2F1 and NuSAP expression in human prostate cancer samples. NuSAP is a novel biomarker for prostate cancer recurrence after surgery and its overexpression appears to be driven in part by E2F1 activation.
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Affiliation(s)
- Z G Gulzar
- Department of Urology, Stanford University School of Medicine, Stanford, CA 94305-5118, USA
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Massoner P, Haag P, Seifarth C, Jurgeit A, Rogatsch H, Doppler W, Bartsch G, Klocker H. Insulin-like growth factor binding protein-3 (IGFBP-3) in the prostate and in prostate cancer: local production, distribution and secretion pattern indicate a role in stromal-epithelial interaction. Prostate 2008; 68:1165-78. [PMID: 18459102 DOI: 10.1002/pros.20785] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Insulin-like growth factor binding protein 3 (IGFBP-3) exerts inhibitory and proapoptotic effects on prostate cancer cells. Serum levels of IGFBP-3 were found to be associated with the risk of prostate cancer, but the data are still inconclusive. We present a detailed analysis of the expression and localization of IGFBP-3 in the prostate and a comparison with its expression pattern in tumors. METHODS Expression and localization of IGFBP-3 were analyzed in cellular models and tissue by real-time RT-PCR, ELISA, immunohistochemistry, and immunofluorescence. RESULTS All cell types of a panel of benign epithelial, stromal and tumor prostate cells expressed IGFBP-3. Significantly higher expression levels were registered in stromal cells. TGF-beta stimulation boosted IGFBP-3 levels 60-fold in stromal cells. The pattern of expression was confirmed in microdissected tissue samples. Protein levels measured by ELISA paralleled the mRNA levels and more than 80% of IGFBP-3 was secreted. On tissue immunostaining, IGFBP-3 was found to be mainly located in the epithelium. The pattern suggested secretion of IGFBP-3, which was confirmed in prostate tissue cultured ex vivo and the ejaculate of vasectomized men. IGFBP-3 levels were increased in primary tumors but did not differ from benign epithelium in metastases and local recurrent tumors. CONCLUSIONS We registered a significant local production of IGFBP-3 in the prostate, which may well override the effect of protein entering from blood. The stroma--particularly reactivated stroma--is the main source of IGFBP-3 in the prostate, suggesting that this peptide acts as a mediator of stromal-epithelial interactions.
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Affiliation(s)
- Petra Massoner
- Department of Urology, Innsbruck Medical University, Innsbruck, Austria
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Flaig TW, Nordeen SK, Lucia MS, Harrison GS, Glodé LM. Conference report and review: current status of biomarkers potentially associated with prostate cancer outcomes. J Urol 2007; 177:1229-37. [PMID: 17382696 DOI: 10.1016/j.juro.2006.11.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Indexed: 11/19/2022]
Abstract
PURPOSE The use of prostate specific antigen screening to diagnose and monitor prostate cancer is associated with well-known shortcomings. A 2-day Prostate Cancer Biomarker Conference was convened to identify promising areas of research and focus efforts on the most critical needs. MATERIALS AND METHODS The conference provided a forum for the presentation and discussion of ongoing prostate cancer biomarker research. This meeting also sought to identify a range of critical issues in the development and validation of biomarkers, foster research collaboration between groups representing government, academic and industry initiatives, and coordinate efforts with planned and ongoing clinical trials. RESULTS Taken collectively the conference presentations offered various new technologies for biomarker discovery and pathological assessment of clinical disease as well as the promise of biomarkers for improving prostate cancer diagnosis and treatment decisions. However, research efforts focused on biomarker validation and implementation clearly lag behind those directed toward initial biomarker discovery. It is apparent that guidelines are desperately needed to ensure the consistency of sample collection across institutions. CONCLUSIONS Several ongoing and planned adjuvant prostate cancer trials will provide a tremendous opportunity for biological sample collection along with the potential to validate many biomarkers. Practicing urologists have an opportunity to have a critical role in the successful accrual of patients into these trials.
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Affiliation(s)
- Thomas W Flaig
- Department of Medicine, University of Colorado at Denver and Health Sciences University Denver, Aurora, Colorado 80045, USA.
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Nelson EC, Cambio AJ, Yang JC, Lara PN, Evans CP. Biologic agents as adjunctive therapy for prostate cancer: a rationale for use with androgen deprivation. ACTA ACUST UNITED AC 2007; 4:82-94. [PMID: 17287869 DOI: 10.1038/ncpuro0700] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 11/15/2006] [Indexed: 12/26/2022]
Abstract
The prevalence of prostate cancer emphasizes the need for improved therapeutic options, particularly for metastatic disease. Current treatment includes medical or surgical castration, which initially induces apoptosis of prostate cancer cells, but ultimately an androgen-independent subpopulation emerges. In addition to a transient therapeutic effect, androgen-deprivation therapy (ADT) can initiate biochemical events that may contribute to the development of and progression to an androgen-independent state. This transition involves multiple signal transduction pathways that are accompanied by many biochemical changes resulting from ADT. These molecular events themselves are therapeutic targets and serve as a rationale for adjunctive treatment at the time of ADT.
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Kim KH, Dobi A, Shaheduzzaman S, Gao CL, Masuda K, Li H, Drukier A, Gu Y, Srikantan V, Rhim JS, Srivastava S. Characterization of the androgen receptor in a benign prostate tissue-derived human prostate epithelial cell line: RC-165N/human telomerase reverse transcriptase. Prostate Cancer Prostatic Dis 2006; 10:30-8. [PMID: 17075604 DOI: 10.1038/sj.pcan.4500915] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The majority of prostate epithelial cell lines stably expressing wild-type (wt) or mutant (mt) androgen receptor (AR) are derived from metastatic prostate cancers. Therefore, the wt AR-expressing RC-165N/human telomerase reverse transcriptase (hTERT) cell line derived from the benign prostate tissue of an African-American patient provides a unique opportunity to assess the functional status of AR in a cellular context not studied before. Although androgen-induced expression of known androgen responsive genes such as PMEPA1, and NDRG1 was observed in RC-165N/hTERT, this cell line expresses prostate-specific antigen (PSA) at significantly lower levels. Chromatin immunoprecipitation assay revealed androgen-dependent binding of AR to androgen response elements of PSA, PMEPA1 and NDRG1 genes. Similarities, as well as differences were noted in the expression of androgen responsive genes between RC-165N/hTERT and LNCaP cells. Comprehensive evaluations of AR functions in RC-165N/hTERT cells suggest that whereas some features of known AR functions are maintained in this benign prostatic tissue-derived cell line, other AR functions are not retained. Objective evaluations of similar cell lines will lead to the understanding of AR functions in prostate growth and differentiation.
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Affiliation(s)
- K-H Kim
- Department of Surgery, Center for Prostate Disease Research, Uniformed Services University, Bethesda, MD 20852, USA
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Gennigens C, Menetrier-Caux C, Droz JP. Insulin-Like Growth Factor (IGF) family and prostate cancer. Crit Rev Oncol Hematol 2006; 58:124-45. [PMID: 16387509 DOI: 10.1016/j.critrevonc.2005.10.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/30/2005] [Accepted: 10/07/2005] [Indexed: 11/28/2022] Open
Abstract
There is abundant in vitro, animal and epidemiologic evidence to suggest that the Insulin-Like Growth Factor (IGF) family is a multi-component network of molecules which is involved in the regulation of both physiological and pathological growth processes in prostate. The IGF family plays a key role in cellular metabolism, differentiation, proliferation, transformation and apoptosis, during normal development and malignant growth. This family also seem essential in prostate cancer bone metastases, angiogenesis and androgen-independent progression. Therapeutic alternatives in men with progressive prostate cancer after androgen ablation are very limited. More effective therapies are needed for these patients. Pharmacologic interventions targeting the IGF family are being devised. Such strategies include reduction of IGF-I levels (growth hormone-releasing hormone antagonists, somatostatin analogs), reduction of functional IGF-I receptor levels (antisense oligonucleotides, small interfering RNA), inhibition of IGF-IR and its signalling (monoclonal antibodies, small-molecule tyrosine kinase inhibitors) and Insulin-Like Growth Factor Binding Proteins.
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Affiliation(s)
- C Gennigens
- Department of Medecine, Division of Hematology/Oncology, University Hospital of Liege, Belgium.
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Miyata Y, Kanda S, Sakai H, Hakariya T, Kanetake H. Relationship between changes in prostate cancer cell proliferation, apoptotic index, and expression of apoptosis-related proteins by neoadjuvant hormonal therapy and duration of such treatment. Urology 2005; 65:1238-43. [PMID: 15922418 DOI: 10.1016/j.urology.2005.01.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 12/24/2004] [Accepted: 01/13/2005] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To investigate the relationships between changes in the carcinoma cell proliferation index, apoptotic index (AI), and apoptosis-related factors, including bcl-2 and bax, after different durations of neoadjuvant hormonal therapy (NHT) in prostate cancer tissue. METHODS Pre- and post-NHT specimens were obtained from 42 patients who had undergone NHT and radical prostatectomy. The patients were divided into two groups according to the duration of NHT: group 1 (3 to 7 months, n = 21) and group 2 (8 to 12 months, n = 21; no randomization). Immunohistochemistry was used to determine the expression of bcl-2 and bax and to determine the proliferation index, and the terminal deoxynucleotidyl transferase-mediated nick end-labeling method was used to assess apoptosis and determine the AI. RESULTS The median proliferation indexes of groups 1 (1.8%) and 2 (1.6%) were significantly lower than the respective values in the pre-NHT specimens (4.9%, P < 0.01). The median AI of group 1 (2.5%) was greater than in the pre-NHT specimens (1.4%). In addition, the post/pre-NHT AI ratio correlated significantly with the duration of NHT in group 1 (r = 0.58, P < 0.01), but not in group 2. Bax expression increased in a manner parallel to that of the AI. CONCLUSIONS NHT suppresses prostate cancer cell proliferation for 3 to 12 months. Although the AI was increased during 3 to 7 months of NHT, no significant difference was found between the pre-NHT levels and those after 8 to 12 months. Our results support the current belief that the optimal duration of NHT is longer than 3 months.
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Affiliation(s)
- Yasuyoshi Miyata
- Department of Urology, Nagasaki University School of Medicine, Nagasaki, Japan.
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Liu B, Lee KW, Li H, Ma L, Lin GL, Chandraratna RAS, Cohen P. Combination therapy of insulin-like growth factor binding protein-3 and retinoid X receptor ligands synergize on prostate cancer cell apoptosis in vitro and in vivo. Clin Cancer Res 2005; 11:4851-6. [PMID: 16000583 DOI: 10.1158/1078-0432.ccr-04-2160] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously identified the retinoid X receptor-alpha (RXRalpha) as an insulin-like growth factor binding protein-3 (IGFBP-3) nuclear binding partner, which is required for IGFBP-3-induced apoptosis. In the current study, we investigated the biological interactions of the RXR ligand, VTP194204 and rhIGFBP-3, in vitro and in vivo. In vitro, IGFBP-3 and VTP194204 individually induced apoptosis, and suppressed cell growth in prostate cancer cell lines in an additive manner. In vivo, LAPC-4 xenograft-bearing severe combined immunodeficiency mice treated daily with saline, IGFBP-3, and/or VTP194204 for 3 weeks showed no effect of individual treatments with IGFBP-3 or VTP194204 on tumor growth. However, the combination of IGFBP-3 and VTP194204 treatments inhibited tumor growth by 50% and induced a significant reduction in serum prostate-specific antigen levels. In terminal nucleotidyl transferase-mediated nick end labeling immunohistochemistry of LAPC-4 xenografts, there was modest induction of apoptosis with either IGFBP-3 or VTP194204 individual treatment, but combination therapy resulted in massive cell death, indicating that IGFBP-3 and VTP194204 have a synergistic effect in preventing tumor growth by apoptosis induction. In summary, this is an initial description of the successful therapeutic use of IGFBP-3 as a cancer therapy in vivo, and shows that combination treatment of IGFBP-3 and RXR ligand has a synergistic effect on apoptosis induction leading to substantial inhibition of prostate cancer xenograft growth. Taken together, these observations suggest that combination therapy with IGFBP-3 and RXR ligands may have therapeutic potential for prostate cancer treatment.
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Affiliation(s)
- Bingrong Liu
- Division of Pediatric Endocrinology, Mattel Children's Hospital at UCLA, California, USA
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