Journal of Nutrition Animal Diets/Enrichment Products...

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huang, C.-S.
Right arrow Articles by Hu, M.-L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huang, C.-S.
Right arrow Articles by Hu, M.-L.
© 2008 American Society for Nutrition J. Nutr. 138:538-543, March 2008

Nutritional Immunology

Lycopene Inhibits Experimental Metastasis of Human Hepatoma SK-Hep-1 Cells in Athymic Nude Mice1,2

Chin-Shiu Huang3, Jiunn-Wang Liao4 and Miao-Lin Hu3,*

3 Department of Food Science and Biotechnology and 4 Graduate Institute of Veterinary Pathology, National Chung-Hsing University, Taichung 40227, Taiwan

* To whom correspondence should be addressed. E-mail: mlhuhu{at}dragon.nchu.edu.tw.


   ABSTRACT
TOP
 ABSTRACT
Introduction
 Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 
Lycopene has been shown to inhibit tumor metastasis in vitro, but it is unclear whether lycopene is antimetastatic in vivo. Here, nude mice were orally supplemented 2 times per week for 12 wk with a low or high dose of lycopene [1 or 20 mg/kg body weight (BW)] or with β-carotene (20 mg/kg BW). Two weeks after the beginning of supplementation, mice were injected once with human hepatoma SK-Hep-1 cells via the tail vein. Plasma levels of matrix metalloproteinase (MMP)-2 and vascular endothelial growth factor (VEGF) increased gradually in tumor-injected mice (tumor controls) following tumor injection but were markedly lowered by lycopene or β-carotene supplementation. Ten weeks after tumor injection, mice were killed and tumor metastasis was found to be confined to the lungs. Compared with the tumor controls, high-lycopene supplementation lowered the mean number of tumors from 14 ± 8 to 3 ± 5 (P < 0.05) and decreased tumor cross-sectional areas by 62% (P < 0.05). High-lycopene supplementation also decreased the positive rate of proliferating cellular nuclear antigen (PCNA), the level of VEGF, and protein expressions of PCNA, MMP-9, and VEGF in lung tissues. However, high-lycopene increased the protein expression of nm23-H1 (an antimetastatic gene) by 133% (P < 0.001). For most variables measured, effects of lycopene were dose dependent and the effect of β-carotene was between those of high-dose and low-dose lycopene. These results show that lycopene supplementation reduces experimental tumor metastasis in vivo and suggest that such an action is associated with attenuation of tumor invasion, proliferation, and angiogenesis.


   Introduction
TOP
 ABSTRACT
 Introduction
Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 
Tumor metastasis, a major cause of death for cancer patients, is a multistep process that includes acquisition of the capacity to separate from the primary tumor and invasion of the underlying basal lamina to gain access to the cardiovascular or lymphatic circulation (1). Circulating tumor cells must then exit the cardiovascular system and proliferate within the stroma of the lung to produce a secondary tumor. Altered expression of the putative metastasis suppressor gene nm23-H1 (2,3) is considered to play an important role during the acquisition of metastatic ability. Furthermore, changes in matrix metalloproteinases (MMP)5 (4–6) and angiogenic factors, such as vascular endothelial growth factor (VEGF) (7–9) and interleukin (IL)-12 (10,11), may contribute to tumor metastasis. MMP-2 and MMP-9 have been implicated in malignant tumor progression, partly because they degrade collagen type IV, V, VII, and X, fibronectin, and gelatin of basement membranes (12–14).

Epidemiologic studies have shown that high-lycopene intakes are associated with lowered risks of several types of cancer (15,16). Recent cohort studies have also shown decreased risks for liver cancer (17) and prostate cancer (18) in people with either high serum levels of lycopene or a regular and high intake of lycopene or tomatoes. In vitro, lycopene has been reported to inhibit the invasion of rat ascites hepatoma AH109A cells in a dose-dependent manner up to 5 µmol/L (19) and to reduce the motility of brain tumor cells (20). We recently showed that lycopene inhibits the migration and invasion of human hepatoma SK-Hep-1 cells in vitro and that these effects are associated with the upregulation of nm23-H1 (21). Hwang and Lee (22) also demonstrated that lycopene inhibits adhesion, invasion, and migration of SK-Hep-1 cells and that these actions are associated with decreased activity of MMP-2 and MMP-9. However, it is unclear whether lycopene is antimetastatic in vivo.

In this study, we employed an in vivo model using nude mice administered lycopene orally for 12 wk and injected with SK-Hep-1 cells once via tail vein 2 wk after lycopene supplementation began. This tumor injection model does not duplicate all of the steps required for metastasis from a primary tumor, but it has the principle advantage of standardizing the onset of the invasion by injection tumor cells into the blood circulation and can be used to measure the ability of malignant cells to extravasate and form tumors in the lungs (23).


   Materials and Methods
TOP
 ABSTRACT
 Introduction
 Materials and Methods
Results
 Discussion
 LITERATURE CITED
 
    Chemicals. Lycopene was purchased from Wako. Anti-nm23 mouse monoclonal antibody and anti-MMP-9 monoclonal antibody were purchased from BD Co. and US-Biological, respectively. Antiproliferating cellular nuclear antigen (PCNA), anti-VEGF, and anti-mouse IgG-horseradish peroxidase polyclonal antibody were purchased from Santa Cruz Biotechnology. VEGF and IL-12 ELISA kit were purchased from R&D. All chemicals used are of reagent or higher grade.

    Hepatocarcinoma cells for injection to nude mice. SK-Hep-1 human hepatoma cells were grown in DMEM containing 10% (v:v) fetal bovine serum, 0.37% (wt:v) NaHCO3, penicillin (100 kU/L), streptomycin (100 kU/L) in a humidified incubator under 5% CO2, and 95% air at 37°C. The survival rate of cells was always higher than 95% by Trypan blue exclusion. Before injection into the mice, the cells were harvested by trypsinization and washed 3 times with cold serum-free medium and then injected in a total volume of 0.1 mL using a 1-mL 27G2 latex-free syringe (BD) within 30 min of harvest.

    Animals, diet, and treatment. Adult (6- to 8-wk-old) male athymic nude mice (17–22 g) were purchased from the Animal Center of the National Science Council. We recently showed that athymic nude mice are better accumulators of lycopene than F344 rats and BALB/c mice and thus should be more useful for studying the in vivo effects of lycopene (24). The study protocol was approved by the Animal Research Committee of National Chung Hsing University.

The mice were housed individually in hanging wire mesh cages with controlled temperature (25 ± 2°C), humidity (65 ± 5%), and alternating 12-h-light/-dark cycles. Upon arrival, the mice were acclimated for 2 wk. During the entire experimental period (including acclimation), the mice consumed a standard rodent diet (Lab 5001, Purina Mills) and water ad libitum. The standard diet contained 59.8% carbohydrate, 23.4% protein, 4.5% crude fat, and 4.5 mg β-carotene/kg and had no detectable amounts of lycopene, as indicated by the supplier.

The mice (7–8 mice per group) were orally administered with lycopene [1 and 20 mg/kg body weight (BW)] or β-carotene (20 mg/kg BW) in corn oil twice per week (25) for 12 wk. The doses and the feeding regimen used here were based on those of our recent study (24) with slight modification. Corn oil alone (10 mL/kg BW) was given to the noninjected control mice. Two weeks into the supplementation, the mice were injected once with SK-Hep-1 cells (5 x 105 cells) into the lateral tail vein (26,27) and blood samples were drawn once per week from the retro-orbital plexus for the measurement of MMP and VEGF. BW were also measured once weekly.

At the end of experiment (10 wk after tumor injection), the mice were killed by CO2 asphyxiation. Blood samples were collected from both the retro-orbital plexus and heart in a 10-mL vacutainer tube containing K3EDTA and were centrifuged (400 xg; 10 min) to obtain plasma. Lungs were grossly examined and we determined the number of pulmonary tumors by counting visible tumor foci (28). A portion of the organ was removed and fixed in 10% buffered formalin. The left lobe of the lung (the largest areas from each lobe) was processed for histological (H&E) staining. Plasma and the remaining tissues were stored at –80°C until analyses.

    Lung metastasis. Macroscopic in all 5 lung lobes of each mouse was pictured at the time of killing. Quantitative analysis of lung metastasis and the cross-sectional area of tumors in randomly selected fields were measured using the image Pro Plus software (Media Cybernetics).

    Gelatin zymography. Plasma activities of MMP-2 and MMP-9 were determined by gelatin zymography according to a protocol developed by Kleiner and Stetler-Stevenson (29). The plasma samples were pooled because of the limited plasma volume per mouse. Before the assay, plasma samples were diluted 1:10 with PBS. The relative MMP activities were quantitated by Matrox Inspector 2.1 software.

    ELISA. VEGF and IL-12 in plasma were quantified separately with the commercial kit by a solid-phase ELISA (R&D System) at a wavelength of 450 nm. Plasma samples were diluted with commercial dilute-solution (1:5) before assay.

    Histology and immunohistochemistry of VEGF and PCNA. Lung metastasis was analyzed by H&E and immunohistochemical (IHC) techniques. Tissues were formalin-fixed, embedded in paraffin, sectioned, and subjected to H&E or IHC staining. IHC staining for VEGF and PCNA was performed using the streptavidin-peroxidase technique, as described previously (30). Positive rates of PCNA and VEGF were quantified by Image Pro Plus software (Media Cybernetics).

    Western blotting. Protein levels of MMP-9, nm23-H1, PCNA, and VEGF in lung tissues were assayed by western blotting. Briefly, lung tissues were homogenized in the Tissue Protein Extraction Reagent obtained from PIERCE and centrifuged (10,000 x g; 5 min). The supernatants were frozen at –80°C until use.

    Measurement of lung tissue carotenoid contents. β-Carotene and lycopene in lung tissues were extracted without saponification using 6.0 mL of CHCl3:CH3OH (2:1, v:v) (31). Retinyl acetate and {alpha}-tocopherol acetate were added as internal standards. This method determines only lycopene and does not allow the differentiation of isomers. The efficiency of extraction of internal standards ranged from 81 to 87% in tissue samples.

    Statistical analysis. Values are expressed as means ± SD and were analyzed using 1-way ANOVA followed by Duncan's multiple range test for comparisons of group means. Chi-square test was used to analyze the frequency distribution of the mice (percent tumor incidence; Table 1). To account for the unequal variances for the lung tissue concentrations of lycopene, we used the Mann-Whitney test for the statistical analysis. Pearson correlation was used for linear regression analyses. All statistical analyses were performed using SPSS for Windows, version 10. Unless specified otherwise, a P-value < 0.05 is considered significant.


View this table:
[in this window]
[in a new window]

  		TABLE 1 Activities of MMP-9 and MMP-2 and concentrations of VEGF and IL-12 in plasma of control and tumor-bearing male nude mice supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or 20 mg β-carotene/kg BW (BC20) for 12 wk12

 

   Results
TOP
 ABSTRACT
 Introduction
 Materials and Methods
 Results
Discussion
 LITERATURE CITED
 
    BW and relative tissue weights. BW did not differ among the 5 groups of nude mice at the start of the study or during and after 12 wk of lycopene supplementation (data not shown). At the time the mice were killed (10 wk after tumor injection), the relative organ weights of the brain, heart, liver, kidney, testis, and spleen did not differ among the groups. However, the lung relative weight of tumor controls (1.45 ± 0.30%) was significantly higher than that of noninjected controls (0.95 ± 0.10%). Supplementation with low and high doses of lycopene or β-carotene for 12 wk significantly decreased the relative lung weights to 1.09 ± 0.63%, 1.00 ± 0.31%, and 1.07 ± 0.13%, respectively, with no significant differences among the treatments.

    Time-course changes in plasma MMP-2 activities and VEGF levels during the experimental period. We determined only the activity of MMP-2 in the plasma during the experimental period because of the limited amounts of plasma. Plasma MMP-2 activities and VEGF levels were significantly induced in tumor controls during the 12-wk experimental period; lycopene supplementation decreased MMP-2 and VEGF in a dose-dependent manner and the effect was evident immediately after tumor injection (Fig. 1). The effect of β-carotene (20 mg/kg BW) was smaller than that of low-lycopene supplementation. Interestingly, plasma MMP-2 activity in the high-lycopene group was lower than that in the nontumor-injected controls over the entire experimental period.


Figure 1
View larger version (14K):
[in this window]
[in a new window]

  		FIGURE 1  Time-course changes in plasma activities of MMP-2 (A) and VEGF (B). Male athymic nude mice were supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or with 20 mg β-carotene/kg BW (BC20) for 12 wk. Two weeks into the supplementation, the mice were injected once with SK-Hep-1 cells (5 x 105 cells). Each data point represents a single replicate obtained from pooled plasma from 7–8 mice per group.

 
    Plasma levels of MMP-9, MMP-2, VEGF, and IL-12 at the time of killing. The plasma activities of MMP-9 and MMP-2 in the tumor controls were significantly elevated by tumor injection (Table 1). High-lycopene treatment significantly decreased the activities of MMP-9 and MMP-2, which did not differ from those of the nontumor-injected controls. Low lycopene and β-carotene significantly decreased only MMP-2 activity. Tumor injection markedly increased the level of VEGF and this increase was essentially abolished by high-lycopene treatment, whereas low lycopene and β-carotene also significantly decreased the VEGF level compared with tumor controls. By contrast, plasma levels of IL-12 significantly decreased with tumor injection and were restored by lycopene (both low and high doses) and β-carotene supplementation.

    Inhibition of experimental metastasis by lycopene. At the time the mice were killed, metastatic nodules were clearly noted microscopically in the lungs of mice that received the tail vein injection with SK-Hep-1 cells (data not shown), whereas only slight tumor formation was observed in the livers of some of the mice and no nodules were found in any other organs examined. Only 1 of the 8 mice in the tumor control group had not developed a lung tumor, whereas 2 of 8 and 4 of 7 mice in the low- and high-lycopene groups, respectively, had no tumor formation (Table 2). The number of tumors was significantly decreased by both high-lycopene and β-carotene treatments and the effects of 2 treatments did not differ.


View this table:
[in this window]
[in a new window]

  		TABLE 2 Lung metastasis and tumors size of metastatic tumors in male nude mice supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or 20 mg β-carotene/kg BW (BC20) for 12 wk12

 
Supplementation with low and high lycopene decreased the tumor cross-sectional area by 19 and 62% (P < 0.05), respectively (Table 2). β-Carotene supplementation also decreased the tumor cross-sectional area 49% to 1.22 ± 0.61 mm2 (P < 0.05).

    Correlation of MMP-9, MMP-2, VEGF, and IL-12 to tumor number. Tumor number in the lungs of nude mice was positively correlated with the activities of MMP-9 (r = 0.98; P = 0.004), MMP-2 (r = 0.93, P = 0.021), and VEGF (r = 0.88, P = 0.041) and negatively correlated with the level of IL-12 (r = –0.75; P = 0.148).

    IHC assays. In vivo cell proliferation and angiogenesis were evaluated using anti-PCNA and anti-VEGF antibodies, respectively (Fig. 2). The percentage of positive PCNA tumor cells in the tumor control group was 6.5-fold greater than in the noninjected control group (P < 0.05) (Table 3). Low- and high-lycopene supplementation decreased percent positive PCNA by ~32 (P = 0.069) and 74% (P < 0.01), respectively, compared with the tumor controls. High-lycopene supplementation was more effective than β-carotene in decreasing percent positive PCNA (74 vs. 49%). The percentage of positive VEGF cells was markedly higher in the tumor controls than in the noninjected controls and low- and high-lycopene supplementation decreased the percent positive VEGF by 21 (P = 0.124) and 54% (P < 0.05), respectively (Table 3). β-Carotene also tended to decrease the percent positive VEGF 32% (P = 0.071).


Figure 2
View larger version (148K):
[in this window]
[in a new window]

  		FIGURE 2  H&E and IHC staining of PCNA and VEGF in lung tissues of nude mice. Nude mice were supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or with 20 mg β-carotene/kg BW (BC20) for 12 wk. Two weeks into the supplementation, the mice were injected once with SK-Hep-1 cells (5 x 105 via tail vein) and were killed at 10 wk after tumor injection. Control (A); tumor control (B; injected with tumor cells); tumor injection with LP1 (C); tumor injection with LP20 (D); and tumor injection with BC20 (E).

 

View this table:
[in this window]
[in a new window]

  		TABLE 3 Positive rates of PCNA and VEGF in lung tissues of male nude mice supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or 20 mg β-carotene/kg BW (BC20) for 12 wk12

 
    PCNA, VEGF, MMP-9, and nm23-H1 protein expressions in lung tissues. Protein expressions of PCNA in the lungs were markedly elevated in the tumor controls and high-lycopene supplementation significantly decreased the level, whereas supplementation with either low lycopene or β-carotene had no effect (Fig. 3; Table 4). Similarly, high-lycopene supplementation significantly decreased the protein expressions of VEGF and MMP-9, whereas supplementation with either low lycopene or β-carotene had no effect. By contrast, tumor injection significantly decreased protein expression of nm23-H1 in lung tissues and low-lycopene supplementation partially restored the protein expression, whereas high-lycopene and β-carotene supplementation completely restored the expression.


Figure 3
View larger version (64K):
[in this window]
[in a new window]

  		FIGURE 3  Protein expressions of PCNA, MMP-9, VEGF, and nm23-H1 in lung tissues of nude mice. Nude mice were supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or with 20 mg β-carotene/kg BW (BC20) for 12 wk. Two weeks into supplementation, mice were injected once with SK-Hep-1 cells (5 x 105 cells) via tail vein and were killed at 10 wk after tumor injection.

 

View this table:
[in this window]
[in a new window]

  		TABLE 4 Protein expressions of PCNA, MMP-9, VEGF, and nm23-H1 in lung tissues of male nude mice supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or 20 mg β-carotene/kg BW (BC20) for 12 wk12

 
    Concentrations of lycopene and β-carotene in tissues of nude mice after supplementation for 12 wk. Lycopene was not detectable in the lung in the nude mice without lycopene supplementation (Table 5). Lycopene supplementation resulted in dose-dependent increases in lycopene concentrations in the lungs. β-Carotene was detectable in the lungs of nude mice before supplementation and was markedly increased in the lungs after supplementation.


View this table:
[in this window]
[in a new window]

  		TABLE 5 Lung tissue concentrations of lycopene and β-carotene of male nude mice supplemented with 1 or 20 mg lycopene/kg BW (LP1, LP20) or 20 mg β-carotene/kg BW (BC20) for 12 wk1

 

   Discussion
TOP
 ABSTRACT
 Introduction
 Materials and Methods
 Results
 Discussion
LITERATURE CITED
 
Although lycopene has been shown to inhibit tumor metastasis in vitro (19–22), little is known whether it is antimetastatic in vivo. We chose SK-Hep-1 cells to study the metastasis in nude mice, because we had investigated the antimetastatic actions and mechanisms of lycopene in vitro (21,32). Tumor metastasis in the nude mice was evidenced by markedly increased plasma levels of MMP-2 and VEGF almost immediately following tumor injection as well as increased MMP-9 and decreased IL-12 levels in the plasma at the end of experiment (10 wk after tumor injection). Tumor metastasis occurred essentially in the lungs where protein expressions of MMP-9, PCNA, and VEGF were significantly increased and the protein expression of nm23-H1 gene was markedly decreased. Importantly, we showed that oral supplementation with lycopene, especially at the higher dose (20 mg/kg BW, 2 times per week) in nude mice injected with tumor cells markedly decreased the tumor metastasis in the lungs and effectively reinstated the protein expression levels of MMP, VEGF, PCNA, and nm23-H1.

A possible mechanism underlying the antimetastatic actions of lycopene is the inhibition of MMP, especially MMP-2 and MMP-9, which degrades collagen type IV, a major component of basement membranes (12–14). Our findings are consistent with those from in vitro studies using SK-Hep-1 cells showing that lycopene inhibits the secretion of MMP-2 and MMP-9 (23) and the expression of MMP-9 protein and mRNA (32). Another possible antimetastatic mechanism of lycopene is by inhibition of angiogenesis, as we observed here that the levels of VEGF, an angiogenic marker, in plasma and tissue were decreased by lycopene supplementation in a dose-dependent manner. In addition, the increases of MMP-2 and MMP-9 are associated with angiogenesis (4–6). Indeed, inhibition of MMP-2 has shown great promise with synthetic inhibitors as antitumor agents (antiangiogenesis, antiproliferation, and antimetastasis) in preclinical models (33).

Another possible antimetastatic mechanism of lycopene is the inhibition of cell proliferation that leads to decreased tumor size (tumor cross-sectional area). PCNA, an auxiliary protein of the DNA polymerase {delta}, is a proliferation-associated marker used in different neoplasms in relation to clinical behavior (34). The PCNA expression, which peaks in late G1 and S phases of the cell cycle (35), is positive in tumor cells (36). In this study, we demonstrated that lycopene supplementation significantly decreased tumor cell proliferation (as shown by decreased percent positive PCNA cells). Our results are similar to those of Tang et al. (37), which showed that lycopene inhibits the growth of human prostate cancer cells in vitro and in BALB/c nude mice. Liu et al. (38) also showed that lycopene protects against smoke-induced lung carcinogenesis in ferrets, possibly through attenuation of PCNA protein expression in lung tissues. Interestingly, Lian et al. (39) showed that apo-10'-lycopeoic acid, a lycopene cleavage product metabolized in mammalian tissues, inhibits lung tumorigenesis in the A/J mouse model in vivo. Similarly, the mechanism of β-carotene on lung tumor prevention may be mediated through its metabolism products, such as β-apo-14'-carotenoic acid, or through their conversion to retinoic acid (40,41).

Still another possible mechanism by which lycopene inhibits metastasis in vivo is through increased expression of nm23-H1, a tumor metastasis suppressor gene (2,3). Decreased expression of nm23 gene was found in some primary lesions of human metastatic hepatoma (42,43). The present findings that lycopene supplementation (at 1 and 20 mg/kg BW) significantly restored nm23-H1 protein expression in lung tissues of tumor-injected nude mice agree with those of our recent report (22) that lycopene upregulates the expressions of nm23-H1 in SK-Hep-1 cells, which may lead to inhibition of cell migration and invasion.

In summary, this study demonstrates that lycopene supplementation markedly inhibits the growth of metastatic tumors developed in the lungs of athymic nude mice injected with human hepatoma cells. These effects of lycopene are likely associated with inhibition of tumor invasion (attenuation of MMP and enhancement of nm23-H1), proliferation (attenuation of PCNA), and angiogenesis (attenuation of MMP and VEGF but enhancement of IL-12) in the lungs of the nude mice. These results warrant further studies of lycopene as a potential chemopreventive or chemotherapeutic agent.


   ACKNOWLEDGMENTS
 
We thank C-H. Chuang, C-Y. Lin, and Y-E. Fan for technical assistance.


   FOOTNOTES
 
1 Supported by grants from the National Science Council, Republic of China (NSC-93-2320-B005-001). Back

2 Author disclosures: C.-S. Huang, J.-W. Liao, and M.-L. Hu, no conflicts of interest. Back

5 Abbreviations used: BW, body weight; H&E, histological; IHC, immunohistochemical; IL, interleukin; MMP, matrix metalloproteinase; PCNA, proliferating cellular nuclear antigen; VEGF, vascular endothelial growth factor. Back

Manuscript received 26 September 2007. Initial review completed 24 November 2007. Revision accepted 20 December 2007.


   LITERATURE CITED
TOP
 ABSTRACT
 Introduction
 Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 

1. Fidler IJ, Gersten DM, Hart IR. The biology of cancer invasion and metastasis. Adv Cancer Res. 1978;28:149–250.[Medline]

2. Steeg PS, Bevilacqua G, Kopper L, Thorgeirsson UP, Talmadge JB, Liotta LA, Sobel ME. Evidence for a novel gene associated with low tumor metastatic potential. J Natl Cancer Inst. 1988;80:200–4.[Abstract/Free Full Text]

3. Hartsough MT, Clare SE, Mair M, Elkahloun AG, Sgroi D, Osborne CK, Clark G, Steeg PS. Elevation of breast carcinoma Nm23–H1 metastasis suppressor gene expression and reduced motility by DNA methylation inhibition. Cancer Res. 2001;61:2320–7.[Abstract/Free Full Text]

4. Birkedal-Hansen H, Moore WG, Bodden MK, Windsor LJ, Birkedal-Hansen B, DeCarlo A, Engler JA. Matrix metalloproteinases: a review. Crit Rev Oral Biol Med. 1993;4:197–250.[Abstract/Free Full Text]

5. Kahari VM, Saarialho-Kere U. Matrix metalloproteinases and their inhibitors in tumour growth and invasion. Ann Med. 1999;31:34–45.[Medline]

6. Chambers AF, Matrisian LM. Changing views of the role of matrix metalloproteinases in metastasis. J Natl Cancer Inst. 1997;89:1260–70.[Abstract/Free Full Text]

7. Salven P, Manpaa H, Orpana A, Alitalo K, Joensuu H. Serum vascular endothelial growth factor is often elevated in disseminated cancer. Clin Cancer Res. 1997;3:647–51.[Abstract]

8. Oshima RG, Lesperance J, Munoz V, Hebbard L, Ranscht B, Sharan N, Muller WJ, Hauser CA, Cardiff RD. Angiogenic acceleration of Neu induced mammary tumor progression and metastasis. Cancer Res. 2004;64:169–79.[Abstract/Free Full Text]

9. Fontanini G, Vignati S, Boldrini L, Chine S, Silvestri V, Lucchi M, Mussi A, Angeletti CA, Bevilacqua G. Vascular endothelial growth factor is associated with neovascularization and influences progression of non-small cell lung carcinoma. Clin Cancer Res. 1997;3:861–5.[Abstract]

10. Angiolillo AL, Sgadari C, Tosato G. A role for the interferon-inducible protein 10 in inhibition of angiogenesis by interleukin-12. Ann N Y Acad Sci. 1996;795:158–67.[Medline]

11. Majewski S, Marczak M, Szmurlo A, Jablonska S, Bollag W. Interleukin-12 inhibits angiogenesis induced by human tumor cell lines in vivo. J Invest Dermatol. 1996;106:1114–8.[CrossRef][Medline]

12. Welgus HG, Fliszar CJ, Seltzer JL, Schmid TM, Jeffrey JJ. Differential susceptibility of type X collagen to cleavage by two mammalian interstitial collagenases and 72-kDa type IV collagenase. J Biol Chem. 1990;265:13521–7.[Abstract/Free Full Text]

13. Liabakk NB, Talbot I, Smith RA, Wilkinson K, Balkwill F. Matrix metalloprotease 2 (MMP-2) and matrix metalloprotease 9 (MMP-9) type IV collagenases in colorectal cancer. Cancer Res. 1996;56:190–6.[Abstract/Free Full Text]

14. Shapiro SD. Matrix metalloproteinase degradation of extracellular matrix: biological consequences. Curr Opin Cell Biol. 1998;10:602–8.[CrossRef][Medline]

15. Clinton SK. Lycopene: chemistry, biology, and implications for human health and disease. Nutr Rev. 1998;56:35–51.[Medline]

16. Gerster H. The potential role of lycopene for human health. J Am Coll Nutr. 1997;16:109–26.[Abstract]

17. Toledo LP, Ong TP, Pinho AL, Jordao A Jr, Vanucchi H, Moreno FS. Inhibitory effects of lutein and lycopene on placental glutathione S-transferase-positive preneoplastic lesions and DNA strand breakage induced in Wistar rats by the resistant hepatocyte model of hepatocarcinogenesis. Nutr Cancer. 2003;47:62–9.[CrossRef][Medline]

18. Wu K, Erdman JW Jr, Schwartz SJ, Platz EA, Leitzmann M, Clinton SK, DeGroff V, Willett WC, Giovannucci E. Plasma and dietary carotenoids, and the risk of prostate cancer: a nested case-control study. Cancer Epidemiol Biomarkers Prev. 2004;13:260–9.[Abstract/Free Full Text]

19. Kozuki Y, Miura Y, Yagasaki K. Inhibitory effects of carotenoids on the invasion of rat ascites hepatoma cells in culture. Cancer Lett. 2000;151:111–5.[CrossRef][Medline]

20. Rooprai HK, Christidou M, Pilkington GJ. The potential for strategies using micronutrients and heterocyclic drugs to treat invasive gliomas. Acta Neurochir (Wien). 2003;145:683–90.[Medline]

21. Huang CS, Shih MK, Chuang CH, Hu ML. Lycopene inhibits cell migration and invasion and upregulates nm23–H1 in a highly invasive hepatocarcinogma, SK-Hep-1 cells. J Nutr. 2005;135:2119–23.[Abstract/Free Full Text]

22. Hwang ES, Lee HJ. Inhibitory effects of lycopene on the adhesion, invasion, and migration of SK-Hep1 human hepatoma cells. Exp Biol Med. 2006;231:322–7.[Abstract/Free Full Text]

23. Li D, Graef GL, Yee JA, Yan L. Dietary supplementation with high-selenium soy protein reduces pulmonary metastasis of melanoma cells in mice. J Nutr. 2004;134:1536–40.[Abstract/Free Full Text]

24. Huang CS, Chuang CH, Hu ML. Effects of lycopene supplementation on plasma and tissue lycopene levels in various rodent strains. Int J Vitam Nutr Res. 2006;76:377–84.[Medline]

25. Kim JM, Araki S, Kim DJ, Park CB, Takasuka N, Baba-Toriyama H, Ota T, Nir Z, Khachik F, et al. Chemopreventive effects of carotenoids and curcumins on mouse colon carcinogenesis after 1,2-dimethylhydrazine initiation. Carcinogenesis. 1998;19:81–5.[Abstract/Free Full Text]

26. Yang M, Baranov E, Jiang P, Sun FX, Li XM, Li L, Hasegawa S, Bouvet M, Al-Tuwaijri M, et al. Whole-body optical imaging of green fluorescent protein-expressing tumors and metastases. Proc Natl Acad Sci USA. 2000;97:1206–11.[Abstract/Free Full Text]

27. Ogawa K, Nakanishi H, Takeshita F, Futakuchi M, Asamoto M, Imaida K, Tatematsu M, Shirai T. Establishment of rat hepatocellular carcinoma cell lines with differing metastatic potential in nude mice. Int J Cancer. 2001;91:797–802.[CrossRef][Medline]

28. Li D, Yee JA, McGuire MH, Murphy PA, Yan L. Soybean isoflavones reduce experimental metastasis in mice. J Nutr. 1999;129:1075–8.[Abstract/Free Full Text]

29. Kleiner DE, Stetler-Stevenson WG. Quantitative zymography: detection of picogram quantities of gelatinases. Anal Biochem. 1994;218:325–9.[CrossRef][Medline]

30. Ramos-Vara JA. Technical aspects of immunohistochemistry. Vet Pathol. 2005;42:405–26.[Abstract/Free Full Text]

31. Lederman JD, Overton KM, Hofmann NE, Moore BJ, Thornton J, Erdman JW. Ferrets (Mustela putoius furo) inefficiently convert beta-carotene to vitamin. J Nutr. 1998;128:271–9.[Abstract/Free Full Text]

32. Huang CS, Fan YE, Lin CY, Hu ML. Lycopene inhibits matrix metalloproteinase-9 and down-regulates the binding activity of nuclear factor-kappa B and stimulatory protein-1. J Nutr Biochem. 2007;18:449–56.[CrossRef][Medline]

33. Bloomston M, Zervos EE, Rosemurgy AS II. Matrix metalloproteinases and their role in pancreatic cancer: a review of preclinical studies and clinical trials. Ann Surg Oncol. 2002;9:668–74.[CrossRef][Medline]

34. Robbins BA, de la Vega D, Ogata K, Tan EM, Nakamura RM. Immunohistochemical detection of proliferating cell nuclear antigen in solid human malignancies. Arch Pathol Lab Med. 1987;111:841–5.[Medline]

35. Bravo R, Frank R, Blundell PA, Macdonald-Bravo H. Cyclin/PCNA is the auxiliary protein of DNA polymerase-delta. Nature. 1987;326:515–7.[CrossRef][Medline]

36. Weber KL, Doucet M, Price JE, Baker C, Kim SJ, Fidler IJ. Blockade of epidermal growth factor receptor signaling leads to inhibition of renal cell carcinoma growth in the bone of nude mice. Cancer Res. 2003;63:2940–7.[Abstract/Free Full Text]

37. Tang L, Jin T, Zeng X, Wang JS. Lycopene inhibits the growth of human androgen-independent prostate cancer cells in vitro and in BALB/c nude mice. J Nutr. 2005;135:287–90.[Abstract/Free Full Text]

38. Liu C, Lian F, Smith DE, Russell RM, Wang XD. Lycopene supplementation inhibits lung squamous metaplasia and induces apoptosis via up-regulating insulin-like growth factor-binding protein 3 in cigarette smoke-exposed ferrets. Cancer Res. 2003;63:3138–44.[Abstract/Free Full Text]

39. Lian F, Smith DE, Ernst H, Russell RM, Wang XD. Apo-10'-lycopenoic acid inhibits lung cancer cell growth in vitro, and suppresses lung tumorigenesis in the A/J mouse model in vivo. Carcinogenesis. 2007;28:1567–74.[Abstract/Free Full Text]

40. Kim Y, Chongviriyaphan N, Liu C, Russell RM, Wang XD. Combined antioxidant (beta-carotene, alpha-tocopherol and ascorbic acid) supplementation increases the levels of lung retinoic acid and inhibits the activation of mitogen-activated protein kinase in the ferret lung cancer model. Carcinogenesis. 2006;27:1410–9.[Abstract/Free Full Text]

41. Prakash P, Liu C, Hu KQ, Krinsky NI, Russell RM, Wang XD. Beta-carotene and beta-apo-14'-carotenoic acid prevent the reduction of retinoic acid receptor beta in benzo[a]pyrene-treated normal human bronchial epithelial cells. J Nutr. 2004;134:667–73.[Abstract/Free Full Text]

42. Fujimoto Y, Ohtake T, Nishimori H, Ikuta K, Ohhira M, Ono M, Kohgo Y. Reduced expression and rare genomic alteration of nm23–H1 in human hepatocellular carcinoma and hepatoma cell lines. J Gastroenterol. 1998;33:368–75.[CrossRef][Medline]

43. Iizuka N, Oka M, Noma T, Nakazawa A, Hirose K, Suzuki T. NM23–H1 and NM23–H2 messenger RNA abundance in human hepatocellular carcinoma. Cancer Res. 1995;55:652–7.[Abstract/Free Full Text]




This article has been cited by other articles:


Home page
 J. Nutr.Home page
C. K. Chow
The Relative Efficacy of Lycopene and {beta}-Carotene in Inhibiting Experimental Metastasis of Human Hepatoma SK-Hep-1 Cells in Athymic Nude Mice
J. Nutr., November 1, 2008; 138(11): 2289 - 2289.
[Full Text] [PDF]

Home page
 J. Nutr.Home page
M.-L. Hu
Response to Dr. Chow
J. Nutr., November 1, 2008; 138(11): 2290 - 2290.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huang, C.-S.
Right arrow Articles by Hu, M.-L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huang, C.-S.
Right arrow Articles by Hu, M.-L.

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Copyright © 2008 by American Society for Nutrition