
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Cancer Therapy: Preclinical |
B Inhibitor in Prostate Cancer
Authors' Affiliations: 1 Department of Urology, Keio University, School of Medicine, Tokyo, Japan and 2 Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
Requests for reprints: Jun Nakashima, Department of Urology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Phone: 81-3-5363-3825; Fax: 81-3-3225-1985; E-mail: njun{at}sc.itc.keio.ac.jp.
| Abstract |
|---|
|
|
|---|
B (NF-
B) inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on IL-6 production and cachexia in an animal model of hormone-refractory prostate cancer. Experimental Design: The association between serum IL-6 levels and variables of cachexia was evaluated in 98 patients with prostate cancer. The inhibitory effects of DHMEQ on IL-6 secretion and cachexia were investigated in in vitro and in vivo studies using JCA-1 cells derived from human prostate cancer.
Results: Serum IL-6 levels were significantly elevated and cachexia developed in JCA-1 tumor-bearing mice as well as in prostate cancer patients with progressive disease. IL-6 secretion was significantly inhibited in JCA-1 cells exposed to DHMEQ. Intraperitoneal administration of DHMEQ (8 mg/kg) to tumor-bearing mice produced a significant amelioration of the reduction in body weight, epididymal fat weight, gastrocnemius muscle weight, hematocrit, and serum levels of triglyceride and albumin when compared with administration of DMSO or no treatment. DHMEQ caused a significant decrease of serum IL-6 level in JCA-1 tumor-bearing mice (all P < 0.05).
Conclusions: These results suggested an association between serum IL-6 and cachexia in patients with prostate cancer and in JCA-1 tumor-bearing mice and that a new NF-
B inhibitor, DHMEQ, could prevent the development of cachexia in JCA-1 tumor-bearing mice presumably through the inhibition of IL-6 secretion. DHMEQ seems to show promise as a novel and unique anticachectic agent in hormone-refractory prostate cancer.
B (NF-
B) is one of the pivotal regulators of cytokine-inducible gene expression (11). Schwarz et al. (12) have suggested that suppression of NF-
B may result in the amelioration of cachexia in a mouse tumor model. It is also well known that NF-
B shows often constitutive activation in hormone-refractory prostate cancer cells (13, 14). As far as we know, no investigators have explored a treatment strategy for cachexia based on the regulation of NF-
B by administration of a compound synthesized from a natural product. Recently, we have investigated the effectiveness of a new NF-
B inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), which is a 5-dehydroxymethyl derivative of epoxyquinomicin C that shows antiNF-
B activity in cultured human leukemia Jurkat cells and inhibits type II collageninduced rheumatoid arthritis in mice (15). The present study was undertaken to evaluate the association between IL-6 and cachexia in patients with prostate cancer, as well as the inhibitory effect of DHMEQ on IL-6 production and cachexia in an animal model of hormone-refractory prostate cancer. | Materials and Methods |
|---|
|
|
|---|
Cell line. JCA-1 cells derived from human prostate cancer (17) were grown in RPMI 1640 supplemented with 10% heat-inactivated fetal bovine serum, 100 µg/mL streptomycin (Life Technologies, Inc., Grand Island, NY), and 100 IU/mL penicillin (Life Technologies).
Chemicals. DHMEQ was synthesized in our laboratory (15). We also referred to the article by Suzuki et al. (18) in which the molecular structure was shown. It was dissolved in DMSO to prepare a 10 mg/mL solution and was subsequently diluted in culture medium to a final DMSO concentration of <0.1%.
In vitro interleukin-6 assay. JCA-1 cells (1 x 105) were seeded in a total volume of 1 mL of medium in each well of 24-well tissue culture plates and allowed to grow overnight. Then cells were treated with 1.0 or 1.5 µg/mL of DHMEQ, whereas other cells treated with the same concentrations of DMSO served as controls. After 48 hours of incubation, the supernatant of each well was collected and stored at 80°C until assay, and the number of viable cells was determined by trypan blue dye exclusion. The IL-6 concentration was measured using an enzyme immunoassay specific for human IL-6 (R&D Systems QuantiGlo Human IL-6 Immunoassay kit) according to the instructions of the manufacturer.
Animal model. All procedures involving animals and their care in this study were approved by the animal care committee of our institution in accordance with institutional and Japanese government guidelines for animal experiments. Male Balb/C-nu/nu mice were obtained from Sankyo Lab Service Corp. (Tokyo, Japan). The mice were housed at a constant temperature and humidity and received a standard diet and water. JCA-1 cells (1 x 107) were inoculated s.c. into the right flank of each mouse. When the tumors reached
10 mm in diameter, mice were randomly assigned to three groups. DHMEQ (8 mg/kg) was administered i.p. in a volume of 0.2 mL once daily for 25 days to group 2 (n = 12). This group was labeled Tumor (+), DHMEQ. To clarify the effect of the vehicle, the same dose of DMSO given to group 2 was injected in another group of mice (group 3, n = 16), and this group was labeled Tumor (+), DMSO, and another group of tumor-bearing mice was observed without any treatment [group 4, n = 11; this group was labeled Tumor (+), No drug]. As a healthy control, age-matched mice were observed without any treatment [group 1, n = 14; this group was labeled Tumor (), No drug]. During the treatment period, mice were carefully monitored and body weight was measured every other day. At the time of sacrifice, the tumor, gastrocnemius muscle, and epididymal fat were dissected and weighed. Blood samples were collected into nonheparinized tubes, and serum was separated within 1 hour of sacrifice. The serum samples were stored at 80°C and thawed just before testing. Serum IL-6 activity was determined using an enzyme immunoassay specific for human IL-6 (R&D Systems QuantiGlo Human IL-6 Immunoassay kit) according to the instructions of the manufacturer. At the same time, the hematocrit and the serum levels of triglycerides and albumin were also measured in each mouse.
Statistical analysis. All values are expressed as the mean ± SE. Variables for different groups were compared using Student's t test or ANOVA; P < 0.05 was considered statistically significant.
| Results |
|---|
|
|
|---|
7 pg/mL than in patients with serum IL-6 level < 7 pg/mL (data not shown). BMI was significantly lower in patients with serum IL-6 level
7 pg/mL (19.38 ± 0.41 kg/m2) than in patients with serum IL-6 level < 7 pg/mL (22.94 ± 0.28 kg/m2; P < 0.0001; Fig. 1).
|
|
|
10 mm in diameter after inoculation of JCA-1 cells, treatment was initiated and the day when treatment was started was designated as day 0. At the end of experiments, the mean weight of tumors of DHMEQ-treated mice was 3.02 ± 0.54 g, which was smaller than that of DMSO-treated mice (4.16 ± 0.81 g) and untreated mice (4.15 ± 1.10 g), but the differences were not statistically significant. The body weight, epididymal fat weight, gastrocnemius muscle weight, hematocrit, and serum levels of triglyceride and albumin were significantly lower in untreated JCA-1 tumorbearing mice (group 4) than in healthy control mice without tumors (group 1), and serum IL-6 levels were significantly elevated in group 4 mice at the time of sacrifice (Figs. 3 and 4; Table 2). Although the body weight of untreated tumor-bearing mice and tumor-bearing mice treated with DMSO decreased in a time-dependent manner, the weight of JCA-1 tumorbearing mice treated with DHMEQ did not decline significantly (Fig. 3). On day 26, body weight (28.24 ± 1.44 g), epididymal fat weight (197.11 ± 31.67 mg), and gastrocnemius muscle weight (499.27 ± 30.26 mg) were significantly greater in DHMEQ-treated mice (group 2) than in mice treated with DMSO alone (group 3; 24.09 ± 1.30 g, 117.12 ± 19.10 mg, and 306.28 ± 24.46 mg; P = 0.018, P = 0.044, and P < 0.001, respectively) or untreated mice (group 4; 21.46 ± 1.08 g, 43.48 ± 2.97 mg, and 261.13 ± 14.54 mg; P = 0.002, P = 0.001, and P < 0.001, respectively; Table 2).
|
|
|
| Discussion |
|---|
|
|
|---|
Alexandrakis et al. (21) showed that IL-6 was significantly higher and hemoglobin was significantly lower in patients with multiple myeloma than in the controls, and a significant decrease in hemoglobin concentration and hematocrit was also found in patients with higher serum IL-6 levels. Ishiko et al. (22) showed that there is severe anemia in cancer-bearing rabbits, whereas the mean hemoglobin value of normal rabbits was much higher. In our study, the serum IL-6 level was significantly higher and hematocrit was significantly lower in JCA-1 tumorbearing mice than in healthy control mice, and DHMEQ significantly prevented the development of anemia and the increase of serum IL-6.
Soda et al. (23) transplanted mice with clone 20 (a subclone of murine colon adenocarcinoma), causing profound weight loss by 15 days after inoculation, and showed that body fat was lost preferentially along with a decrease in the plasma triglyceride level. Fat constitutes 90% of the fuel reserve in adults and depletion of fat is commonly seen in cancer patients with cachexia, whereas Strassmann and Kambayashi (24) reported that IL-6 may decrease carcass lipids. Path et al. investigated the effects of IL-6 on adipocyte functions. They found that chronic incubation of adipocytes with 1 nmol/L IL-6 during differentiation reduced glycero-3-phosphate dehydrogenase activity, a marker of adipocyte differentiation, and triglyceride synthesis to 67 ± 9% of the basal level (P < 0.05; ref. 25). Naoe et al. (26) showed that a significant decrease in the circulating levels of triglyceride was found in the saline-treated tumor-bearing mice compared with the saline-treated normal mice. In the present study, DHMEQ significantly inhibited the decrease of epididymal fat weight and serum triglycerides, presumably through the suppression of IL-6 production.
Oka et al. reported that serum albumin levels were significantly lower in patients with esophageal squamous cell carcinoma who had high serum levels of IL-6 when compared with patients who had lower IL-6 levels. They suggested that IL-6, which is produced by tumor cells, may be related to various disease variables in patients with esophageal squamous cell carcinoma, as well to the nutritional status (27). Tisdale (28) also reported that IL-6 may play a role in muscle wasting in certain animal tumors, possibly via both lysosomal (cathepsin) and nonlysosomal (proteasome) pathways. We showed that JCA-1 tumorbearing mice showed a significant decrease in gastrocnemius muscle weight and serum albumin, and changes were significantly prevented by DHMEQ.
The regulation of many cytokine genes, including IL-6, is relatively simple, and the transcriptional factor NF-
B has been reported to up-regulate various cytokines (2931). Several approaches to inhibit the activation of NF-
B have been investigated (32). A recombinant adenovirus vector expressing the stable form (I
B
) induces apoptosis of cancer cells showing constitutive NF-
B activity in vitro (33). Kawamura et al. developed synthetic double-stranded oligodeoxynucleotides for use as "decoy" cis elements that block the binding of nuclear factors to the promoter regions of target genes. They injected decoy oligodeoxynucleotide targeting NF-
B directly into adenocarcinoma colon 26 tumors in mice to examine whether or not cachexia was alleviated by inhibiting the action of cytokines, and their results suggested that cytokines regulated by NF-
B may play a pivotal role in the induction of cachexia in the colon 26 model (34). However, the clinical feasibility of gene therapy for inhibiting NF-
B is limited by the need for intratumoral delivery of a vector that expresses the NF-
B inhibitor, and few studies have assessed the usefulness of this strategy with in vivo models. In contrast, we assessed a novel agent for inhibiting the activity of NF-
B. There have been no previous reports about the therapeutic effect of an agent synthesized from a natural product on cachexia mediated through the regulation of cytokines by NF-
B.
We have previously reported that DHMEQ produces a significant decrease in NF-
B activity in JCA-1 cells with constitutive NF-
B activation (35). Because of these encouraging in vitro findings, we investigated the effect of DHMEQ on cachexia induced by JCA-1 tumor secreting IL-6. We found that DHMEQ significantly inhibited IL-6 production and significantly prevented the development of cachexia in a JCA-1 tumor model.
In conclusion, we showed a significant association between IL-6 and cachexia in patients with progressive prostate cancer, as well as in JCA-1 tumorbearing mice, and we showed that DHMEQ inhibits NF-
B and thus prevents the development of cachexia induced by prostate cancer in an animal model. Prevention of the complex syndrome of cachexia will improve the quality of life for cancer patients. The new NF-
B inhibitor, DHMEQ, seems to be a promising novel anticachectic agent for the treatment of hormone-resistant prostate cancer.
| Acknowledgments |
|---|
| Footnotes |
|---|
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Received 12/11/04; revised 4/23/05; accepted 5/ 9/05.
| References |
|---|
|
|
|---|
mediates changes in tissue protein turnover in a rat cancer cachexia model. J Clin Invest 1993;92:27839.
B: ten years after. Cell 1996;87:1320.[CrossRef][Medline]
B/I
B proteins in cancer: implications for novel treatment strategies. Surg Oncol 1999;8:14353.[CrossRef][Medline]
B kinase
and NF-
B in prostate cancer cells is inhibited by ibuprofen. Oncogene 1999;18:738994.[CrossRef][Medline]
B in preventing TNF-
-induced cell death in prostate cancer cells. J Urol 1999;161:6749.[CrossRef][Medline]
B activation inhibitors derived from epoxyquinomicin C. Bioorg Med Chem Lett 2000;10:8659.[CrossRef][Medline]
B inhibitor. Tetrahedron 2004;60:70616.[CrossRef]
B. Annu Rev Cell Biol 1994;10:40555.[CrossRef][Medline]
B in the immune system. Annu Rev Immunol 1994;12:14179.[Medline]
B-
proteolysis by site-specific, signal-induced phosphorylation. Science 1995;267:14858.
B prevents TRAIL-induced apoptosis in renal cancer cells. Oncogene 2001;20:388896.[CrossRef][Medline]
B binding site inhibits cachexia in a mouse tumor model. Gene Ther 1999;6:917.[CrossRef][Medline]
B inhibitor in nude mice. Cancer Res 2003;63:10710.This article has been cited by other articles:
![]() |
Z. Meng, N. Mitsutake, M. Nakashima, D. Starenki, M. Matsuse, S. Takakura, H. Namba, V. Saenko, K. Umezawa, A. Ohtsuru, et al. Dehydroxymethylepoxyquinomicin, a Novel Nuclear Factor-{kappa}B Inhibitor, Enhances Antitumor Activity of Taxanes in Anaplastic Thyroid Cancer Cells Endocrinology, November 1, 2008; 149(11): 5357 - 5365. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-J. Nai, Z.-W. Jiang, Z.-M. Wang, N. Li, and J.-S. Li Prevention of Cancer Cachexia by Pyrrolidine Dithiocarbamate (PDTC) in Colon 26 Tumor-Bearing Mice JPEN J Parenter Enteral Nutr, January 1, 2007; 31(1): 18 - 25. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. F. McCarty and K. I. Block Preadministration of High-Dose Salicylates, Suppressors of NF-{kappa}B Activation, May Increase the Chemosensitivity of Many Cancers: An Example of Proapoptotic Signal Modulation Therapy. Integr Cancer Ther, September 1, 2006; 5(3): 252 - 268. [Abstract] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |