Heesook Park

A high-fat diet increases angiogenesis, solid tumor growth, and lung metastasis of CT26 colon cancer cells in obesity-resistant BALB/c mice.

We evaluated whether high‐fat diet (HFD), in the absence of increased calorie intake, increases colon cancer growth and metastasis. Four‐week‐old male BALB/c mice were fed on an HFD (60 kcal% fat) or control diet (10 kcal% fat) for 16 wk, after which CT26 colon cancer cells were subcutaneously injected into the right flank. Solid tumor growth and the number and volume of tumor nodules in the lung were increased markedly in the HFD group with only a slight increase in body weight (5.9%). HFD feeding increased tumor tissue levels of Ki67, cyclin A, cyclin D1, CDK2, Bcl‐xL, and Bcl‐2; reduced p53 levels and TUNEL‐positive apoptotic cells; increased the levels of CD45, CD68, CD31, VEGF, P‐VEGF receptor‐2, iNOS, and COX‐2 as well as hemoglobin content; and increased the levels of HIF‐1α, P‐STAT3‐Y705, P‐STAT3‐S727, P‐IκB‐α, P‐p65, p65, P‐c‐Jun, P‐Akt, P‐ERK1/2, P‐p38, and P‐SAPK/JNK. HFD feeding increased the serum levels of EGF, insulin, IGF‐I, IFN‐γ, leptin, RANTES, MCP‐1, IL‐1ra, and SDF‐1α and media conditioned by epididymal fat tissue explants from HFD‐fed mice caused an increase in microvessel outgrowth from the mouse aorta and tube formation of human umbilical vein endothelial cells. These results indicate that the chronic consumption of an HFD increases colon cancer cell proliferation, tumor angiogenesis, and lung metastasis in mice in the absence of discernible weight gain. HFD feeding increases the levels of growth factors which activate transcription factors, thereby inducing the expression of many genes involved in the stimulation of inflammation, angiogenesis, and cellular proliferation.

Hexane/ethanol extract of Glycyrrhiza uralensis and its active compound isoangustone A induce G1 cycle arrest in DU145 human prostate and 4T1 murine mammary cancer cells.

Although licorice is known to exert anticarcinogenic effects, it contains large quantities of glycyrrhizin (GL), which causes severe hypertension. We have previously demonstrated that the hexane/ethanol extract of Glycyrrhiza uralensis (HEGU) contains no detectable GL and suppresses doxorubicin-induced apoptosis in H9c2 rat cardiac myoblasts. The principal objective of this study was to determine whether and by what mechanism HEGU and its active component, isoangustone A, inhibit cell-cycle progression in DU145 human prostate and 4T1 mouse breast cancer cells. HEGU and isoangustone A dose-dependently decreased DNA synthesis and induced G1 phase arrest in both DU145 and 4T1 cells. HEGU and isoangustone A reduced the levels of CDK2 and CDK4 as well as cyclin A and cyclin D1 proteins, and also induced a decrease in CDK2 activity. The addition of HEGU to drinking water significantly suppressed the orthotopic growth of 4T1 allografts and the expression of the proliferating nuclear cell antigen, CDK2 and CDK4 proteins in the tumor tissues. These results demonstrate the potential of HEGU containing isoangustone A as an antitumor agent.

3,3'-diindolylmethane suppresses 12-O-tetradecanoylphorbol-13-acetate-induced inflammation and tumor promotion in mouse skin via the downregulation of inflammatory mediators.

3,3′‐Diindolylmethane (DIM) is a major acid‐condensation product of indole‐3‐carbinol and is present in cruciferous vegetables. In this study, we evaluated the effects of DIM on antiinflammatory and antitumor promotion activity in mouse skin and explored the relevant mechanisms. When 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) was applied topically to the mouse ear to induce inflammation, DIM pretreatment effectively inhibited TPA‐induced ear edema formation. To evaluate the mechanisms underlying DIMs antiinflammatory effects, DIM was topically treated to the shaved backs of mice 30 min before TPA treatment. DIM inhibited the TPA‐induced increases in the expression of cyclooxygenase (COX)‐2, inducible nitric oxide synthase (iNOS), chemokine (C‐X‐C motif) ligand (CXCL) 5, and interleukin (IL)‐6 in mouse skin. DIM also inhibited nuclear factor‐kappa B (NF‐κB)s DNA binding activity, the nuclear translocation of p65, and the degradation of inhibitor of κB (IκB) α in TPA‐stimulated mouse skin. Furthermore, DIM reduced TPA‐induced increases in the activity of extracellular signal regulated protein kinase (ERK)‐1/2 and IκB kinase (IKK). When mouse skin papillomas were initiated via the topical application of 7,12‐dimethylbenz[α]anthracene (DMBA) and promoted with repeated topical applications of TPA, repeated topical applications of DIM prior to each TPA treatment significantly suppressed the incidence and multiplicity of the papillomas. DIM also reduced the expression of COX‐2 and iNOS, ERK phosphorylation, and the nuclear translocation of p65 in papillomas. Collectively, these results show that DIM exerts antiinflammatory and chemopreventive effects in mouse skin via the downregulation of COX‐2, iNOS, CXCL5, and IL‐6 expression, which may be mediated by reductions in NF‐κB activation.

A High-Fat Diet Containing Lard Accelerates Prostate Cancer Progression and Reduces Survival Rate in Mice: Possible Contribution of Adipose Tissue-Derived Cytokines

To examine the effects of high-fat diet (HFD) containing lard on prostate cancer development and progression and its underlying mechanisms, transgenic adenocarcinoma mouse prostate (TRAMP) and TRAMP-C2 allograft models, as well as in vitro culture models, were employed. In TRAMP mice, HFD feeding increased the incidence of poorly differentiated carcinoma and decreased that of prostatic intraepithelial neoplasia in the dorsolateral lobes of the prostate, which was accompanied by increased expression of proteins associated with proliferation and angiogenesis. HFD feeding also led to increased metastasis and decreased survival rate in TRAMP mice. In the allograft model, HFD increased solid tumor growth, the expression of proteins related to proliferation/angiogenesis, the number of lipid vacuoles in tumor tissues, and levels of several cytokines in serum and adipose tissue. In vitro results revealed that adipose tissue-conditioned media from HFD-fed mice stimulated the proliferation and migration of prostate cancer cells and angiogenesis compared to those from control-diet-fed mice. These results indicate that the increase of adipose tissue-derived soluble factors by HFD feeding plays a role in the growth and metastasis of prostate cancer via endocrine and paracrine mechanisms. These results provide evidence that a HFD containing lard increases prostate cancer development and progression, thereby reducing the survival rate.

Abstract 1823: Chronic consumption of a high-fat diet stimulates tumor growth and metastasis via the activation of key transcription factors in a CT26 mouse colon cancer allograft model

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL We previously demonstrated that dietary fat increased solid tumor growth and metastasis of CT26 colon cancer cells when injected subcutaneously into BALB/c mice. The present study examined the mechanisms by which high-fat diet (HFD) feeding stimulates tumor development and progression. 4-week old, male BALB/c mice were fed a purified diet containing 34.9% (w/w) fat or 4.3% fat (control diet) for a period of 16 weeks. After 16 weeks, CT26 cells were injected subcutaneously into the animals’ left flank. 4.5 weeks after cell injection, mice were killed. In the tumor tissues of mice fed on the HFD, the expression of hypoxia-inducible factor (HIF)-1 and inducible nitric oxide synthase (iNOS) was increased markedly, which was accompanied by a marked increase in the expression of platelet endothelial cell adhesion molecule-1 (CD31, an angiogenesis marker) and vascular endothelial growth factor (VEGF), a down stream target gene product of HIF-1α. Conditioned media by explants of epididymal fat tissues from the HFD-fed mice caused an increase in microvessel outgrowth from the mouse aorta. The infiltration of macrophages was increased into tumor tissues of mice fed on the HFD. Additionally, the levels of chemoattractants and pro-inflammatory cytokines (IFN-γ, IL-1ra, RANTES, MCP-1, SDF-1α, and leptin) were increased in the sera of the HFD group compared to the control group. The expression of p53, another downstream target gene of HIF-1α, was reduced and that of BCL-xL was increased in the tumor tissues obtained from the mice fed on the high-fat diet. These changes in p53 and Bcl-xL may have induced a reduction in the apoptosis of tumor cells in the mice fed on the HFD. In addition to changes in the expression of proteins involved in the regulation of apoptosis, the expression of the cell proliferation marker ki67 as well as that of other proteins involved in the stimulation of cell cycle progression, including cyclin-dependent kinase (CDK)2, CDK4, cyclin D1, and cyclin A, was increased in the tumor tissues from mice fed on the HFD. The levels of phosphorylated ERK1/2, AKT, IκB-α, NFκB p65, VEGFR-2, c-Jun and signal transducer and activator of transcription (STAT3, pY705, pS727) were increased in the tumor tissues of HFD-fed mice. Together, these results suggest that, in obese mice, pro-angiogenic and pro-inflammatory cytokines/chemokines generated by adipose tissues stimulate tumor growth and macrophage infiltration into the tumor microenviroment, and thus play an important role in the activation of the key transcription factors HIF-1α, NFκB, and STAT3; this subsequently activates the transcription of many genes involved in the stimulation of inflammation, proliferation, and angiogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1823. doi:10.1158/1538-7445.AM2011-1823

Abstract 5562: High-fat diet feeding increases tumor growth and metastasis of mammary carcinoma cells in the 4T1 orthotopic BALB/c mouse model

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL We previously observed that chronic consumption of a high fat-diet (HFD) increased the breast cancer-related mortality in the 4T1 orthotopic mouse breast cancer model. In the present study, we determined whether feeding mice with a HFD for a prolonged period increases solid tumor growth and metastasis of breast cancer cells using the 4T1 orthotopic model. 4-week old, female BALB/c mice were fed a purified diet containing 60 kcal% fat (HFD) or 10 kcal% fat (control diet) for a period of 16 weeks. After 16 weeks, 4T1 mammary carcinoma cells (5 × 104 cells) were injected into the inguinal mammary fat pad of syngeneic female BALB/c mice and the mice were continuously fed the same diets. Solid tumor growth was increased in the HFD group as compared to the control diet group. Additionally, chronic consumption of the HFD markedly increased the number and volume of tumor nodules in the lung and liver. The expression of cyclin-dependent kinase (CDK)2, CDK4, cyclin D1, cyclin A, Ki67, vascular endothelial growth factor, CD31 (an angiogenesis marker), and CD45 (a monocyte/macrophage marker) was markedly increased in the tumor tissues in the HFD group as compared to control diet group. The protein levels of urokinase-type plasminogen activator (uPA), intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule-1 were significantly increased but those of plasminogen activator inhibitor-1 were decreased in the lung tissues of the HFD group as compared to control diet group. The serum levels of complement fragment 5a (C5a), interleukin (IL)-6, macrophage colony stimulating factor (M-CSF), soluble intercellular adhesion molecule (sICAM)-1, tissue inhibitors of metalloproteinase (TIMP)-1, and triggering receptor expressed on myeloid cells (TREM)-1 were up-regulated in the HFD group as compared to control diet group. We conducted in vitro assays to determine effect of these cytokines, which had been increased in the sera of mice fed on the HFD, on the cell proliferation, adhesion, and migration of 4T1 cells. sICAM-1 increased the viability of 4T1 cells. TREM-1, M-CSF, and sICAM-1 significantly increased the migration of 4T1 cells. Additionally, the capacity of 4T1 cells to adhere to strips coated with human collagen type I was increased by C5a, sICAM-1, IL-16, M-CSF, TIMP-1, and TREM-1. These results indicate that, in addition to adhesion molecules, metalloproteases and pro-angiogenic factors, the cytokines C5a, sICAM-1, IL-16, M-CSF, TIMP-1, and TREM-1 play important roles in the metastasis of mammary cancer cells in mice fed on a HFD for a prolonged period. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5562. doi:10.1158/1538-7445.AM2011-5562

Abstract 1824: Effects of high-fat diet feeding on solid tumor growth and lung metastasis in the Lewis lung cancer allograft model

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Epidemiological studies indicate that overweight and obesity are associated with increased risk of developing several cancers. In the present study, we determined whether a chronic consumption of a high-fat diet increases solid tumor growth and metastasis in the C57BL/6N mouse lung cancer allograft model. Four-week old, male C57BL/6N mice were fed a purified diet containing 34.9% (w/w) fat (high fat diet) or 4.3 % fat (control diet) for 16 weeks, and then Lewis lung carcinoma cells were subcutaneously injected at 5 × 104 cells per mouse into the animals’ left flank. The primary tumor was resected 3 weeks later, and all animals were killed 21 days after the surgery. The high-fat diet feeding significantly increased the body weights and energy intakes as compared with those in the control diet group. The weights of the liver, spleen, epididymal fat pad, and mesenteric fat pad were increased in the high-fat diet group compared to the control group. The high fat diet increased solid tumor growth as well as the number and the size of colonies in the lung. Immunohistochemical staining of tumor tissues revealed that the expression of Ki67 (prototypic cell cycle related nuclear antigen), CD45 (phospho-tyrosine phosphatase), CD31 (platelet endothelial cell adhesion molecule-1), vascular endothelial growth factor (VEGF), cyclin-dependent kinase 4, cyclin A, and cyclin D1 was significantly increased in the high-fat diet group compared to the control group. The high-fat diet feeding significantly increased the blood levels of leptin, monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), granulocyte-colony stimulating factor (G-CSF), triggering receptor expressed on myeloid cells-1 (TREM-1), angiopoietin-1 (Ang-1), chemokine ligand 16 (CXCL16), plasminogen activator inhibitor-1 (PAI-1), and stromal cell-derived factor-1 (SDF-1) compared to the control group. Results of the present study indicate that the prolonged consumption of a high-fat diet enhances the secretion of cytokines, chemokines, matrix metalloproteinases, and angiogenesis-related proteins and increases the infiltration of macrophages into tumor tissues which, in turn, stimulate the proliferation and metastasis of lung cancer cells. The increased angiogenesis probably contributes to increased tumor growth and metastasis in mice fed on a high-fat diet. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1824. doi:10.1158/1538-7445.AM2011-1824

Abstract 1445: Growth inhibitory and anti-metastatic effects of the hexane/ethanol extract of Glycyrrhiza uralensis in a mouse breast cancer xenograft model

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Glycyrrhiza uralensis (licorice) is one of the most frequently prescribed ingredients in Oriental medicine and licorice root extracts have previously been shown to exhibit anti-carcinogenic activities. However, these extracts harbor considerable quantities of glycyrrhizin, which is known to exert anticarcinogenic activities and to induce severe hypokalemia and hypertension. In this study, we evaluated the effects of the hexane/ethanol extract of Glycyrrhiza uralensis (HEGU), which lacks glycyrrhizin, on the metastatic characteristics of 4T1 murine mammary carcinoma cells. When 4T1 cells were cultured on a transwell-filter in an in vitro cell culture model, HEGU inhibited cell migration and adhesion in a dose-dependent manner. Gelatin zymography and Western blot analysis showed that HEGU significantly suppressed the secretion and activation of the matrix metalloproteinase (MMP)-2 and MMP-9. The secretion of tissue inhibitor of metalloproteinase (TIMP)-1 was reduced in HEGU-treated cells. HEGU reduced the protein levels of intercellular adhesion molecule and vascular cell adhesion molecule. To assess the effects of HEGU on lung metastasis in vivo, we injected 4T1 cells (5×104 cells) into the inguinal mammary fat pads of syngeneic, immunocompetent BALB/c mice. One week after 4T1 cell injection, the mice were given HEGU (5 mg/kg body weight/day) in the drinking water for 25 days. HEGU treatment inhibited the solid tumor growth and the number of pulmonary tumor nodules. Immunohistochemistry results revealed that HEGU treatment reduced the expression of CD31, vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen and cyclin-dependent kinase 4 in the tumor tissues. In addition, the serum concentrations of MMP-9 and VEGF were decreased in the sera of mice treated with HEGU. In the present study, we have demonstrated in both in vivo and in vitro systems that HEGU greatly inhibits the growth and lung metastasis of 4T1 cells, which was accompanied by reduced levels of MMPs, adhesion molecules and VEGF. These data suggest that HEGU possesses chemotherapeutic efficacy against breast cancer including the growth of tumor and inhibition of metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1445.

Abstract 1449: Chronic consumption of a high fat diet increases solid tumor growth and lung metastasis in BALB/c mice subcutaneously injected with CT26 colon cancer cells

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Epidemiological and laboratory animal studies suggest that dietary factors in general and specifically high dietary fat and calories increase the risk of colon cancer. In the present study, we determined whether dietary fat increases solid tumor growth and metastasis of colon cancer using a CT26 mouse colon cancer xenograft model. Four-week old, male BALB/c mice was fed a purified diet containing 34.9% (w/w) fat (high fat diet, HFD), or 4.3% fat (low fat diet, LFD) for a period of 16 weeks. After 16 weeks, CT26 colon cancer cells were injected subcutaneously into the animals’ right flank. 5 weeks after cell injection, animals were killed. The mean body weight was slightly increased in the HFD group (33.9 ± 0.46 g) as compared to the LFD group (31.9 ± 0.37 g). The weights of the liver, lung, and epididymal fat pad were also increased in animals fed the high fat diet. Solid tumor growth (tumor volumes and weights) and the number and volume of tumor nodules in the lung were markedly increased in the HFD group as compared to the LFD group. Immunohistochemical staining of tumor tissues revealed that the expression of proliferating cell nuclear antigen (PCNA), platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31, an angiogenesis marker), vascular endothelial growth factor, and phospho-tyrosine phosphatase (CD 45, a monocytes/macrophage marker) was markedly increased in the HFD group as compared to those in the LFD group. Results from cytokine array revealed that the expression of IFN-γ, IL-1ra, IL-16, CXCL9, MIP-2, CCL5, and TNF-α was up-regulated in the sera of the HFD group as compared to the LFD group. These results indicate that increases in angiogenesis, infiltration of monocytes and cytokine expression probably contribute to increased tumor growth and lung metastasis in mice fed the high fat diet. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1449.