*2.4. RI Improved the Gross and Histopathology of Gastric Tissue*

The recent study investigated the gastroprotective effect of RI in HCl/EtOH-induced gastric ulcer in mice. HCl/EtOH-induced severe gastric damage, which was notably attenuated by RI pretreatment (Figure 3a, upper panel). In addition, the histological study confirmed that the stomach had the normal structure of mucosa in control group. Besides, in the HCl/EtOH-treated mice, epithelial destruction and inflammatory cells infiltration were found in the mucosa and submucosal area. However, RI and ranitidine-treated groups markedly improved the histopathological changes as compared to HCl/EtOH-treated group (Figure 3a, lower panel). These data are well correlated with the protective abilities of RI against gastric ulcer. Likewise, the gross and histological lesions index of gastric tissue was significantly reduced (*p* < 0.05) by pretreatment with RI and ranitidine treated groups than in HCl/EtOH-induced gastric ulcer mice (Figure 3b,c).

#### *2.5. RI Regulated the NO and MDA Production in Gastric Tissue*

To evaluate the oxidative stress level, the NO and MDA production was measured in gastric tissue. After inducing gastric injury, HCl/EtOH significantly (*p* < 0.05) decreased NO and increased MDA production. Overall, pretreatment with the RI effectively (*p* < 0.05) increased and decreased the NO and MDA production as related to standard drug ranitidine, respectively (Figure 2c,d). Therefore, results evidently reveal that RI reduced the oxidative stress in HCl/EtOH-stimulated gastric ulcer for its strong anti-oxidant and anti-inflammatory capacity.

**Figure 3.** Protective role of RI on HCl/EtOH-induced gastric damage in mice: (**a**) gross lesion (upper panel) and histological lesion (lower panel) (scale bar. 200 μm); (**b**) gross lesion index; and (**c**) histological index. # *p* < 0.05 when compared with the control and \* *p* < 0.05 when compared with HCl/EtOH. Data are expressed as mean ± SEM.

#### *2.6. RI Suppressed the Activation Pro-Inflammatory Cytokines in Gastric Tissue*

Pro-inflammatory cytokines play a fundamental role in various types of inflammation. To elucidate the protective role of RI, the gene expression of pro-inflammatory cytokines was examined in the glandular stomach samples by qPCR analysis. The gene expression level of *TNF-α*, *IL-1β*, *IL-6*, *iNOS*, and *COX-2* were gradually upregulated (*p* < 0.05) in the HCl/EtOH-treated group as compared to the control, whereas pretreatment with RI and ranitidine groups significantly (*p* < 0.05) downregulated the cytokines expression level than in the HCl/EtOH-treated group (Figure 4a–e). Thus, data suggest that RI inhibited the gene expression of pro-inflammatory cytokines in gastric tissue and thereby mitigated the gastric inflammation.

### *2.7. RI Inhibited the COX-2 Expression in Gastric Tissue*

It is recognized that elevated expression of COX-2 plays a vital role in the inflammatory process and previous study has revealed that HCl/EtOH strongly activates COX-2 expression in gastric tissue [17]. COX-2 expression in the gastric mucosal epithelial cells was revealed by immunohistochemical staining analysis. As observed, COX-2 was slightly expressed in the normal control gastric mucosal epithelial cells; in contrast, HCl/EtOH increased the COX-2 expression of gastric mucosal epithelial cells, which was mostly observed in the gastric mucosal inflammatory area (Figure 5a). The expression of COX-2 was markedly (*p* < 0.05) blocked by the pretreatment of RI as related to the standard drug ranitidine (Figure 5b). Thus, RI significantly blocked the activation of COX-2 expression in the gastric mucosal inflammatory area and reduced the inflammatory activity.

**Figure 4.** Protective role of RI on gene expression of pro-inflammatory cytokines in gastric tissue. In HCl/EtOH-treated mice, gene expression level of: (**a**) *TNF-α*; (**b**) *IL-1β*; (**c**) *IL-6*; (**d**) *iNOS*; and (**e**) *COX-2* were significantly upregulated, whereas pretreatment with the RI markedly downregulated the gene expression level as related to ranitidine. # *p* < 0.05 when compared with control and \* *p* < 0.05 when compared with HCl/EtOH. Data are expressed as mean ± SEM.

**Figure 5.** Protective role of RI on COX-2 immunoreactivity in the gastric tissue: (**a**) COX-2 expression in gastric mucosal epithelial cells; and (**b**) COX-2 positive immune-stained cells. Scale bar, 200 μm. # *p* < 0.05 when compared with the control and \* *p* < 0.05 when compared with HCl/EtOH. Data are expressed as mean ± SEM.

#### *2.8. RI Blocked the MAPK Cascade, COX-2, and NF-κB Activation*

To find the possible molecular mechanisms of the anti-inflammatory and gastroprotective role of RI, the protein expression related to anti-inflammation signaling pathways was evaluated. The present data showed that LPS treatment remarkably elevated the phosphorylation of MAPK family protein (ERK1/2, JNK, and p38) in RAW 264.7 cells, whereas RI pretreatment notably (*p* < 0.05) attenuated the phosphorylation of MAPK proteins (Figure 6, upper panel). Meanwhile, LPS and HCl/EtOH treatment increased COX-2 expression in RAW 264.7 cells and gastric tissues were markedly (*p* < 0.05) blocked by RI pretreatment (Figure 6, middle panel). After LPS and HCl/EtOH stimulation, IκBα and NF-κB phosphorylation were noticeably (*p* < 0.05) increased, indicating the activation of NF-κB. However, IκBα phosphorylation and the nuclear translocation of NF-κB (p65) were gradually reduced (*p* < 0.05) by RI pretreatment (Figure 6, middle and lower panels). Moreover, RI alone does not seem to

involve in the signal pathways in vitro study. Together, these results demonstrate that RI significantly inhibited the phosphorylation of MAPK cascade in RAW 264.7 cells as well as activation of COX-2, IκBα, and NF-κB in RAW 264.7 cells and gastric tissues, simultaneously.

**Figure 6.** Protective role of RI on the MAPK cascades, COX-2 expression, and activation of IκBα, NF-κB in RAW 264.7 cells and gastric tissue. Here, upper and middle panels represent the MAPKs (pERK1/2, pJNK, and pp38), COX-2, IκBα and NF-κB expression in RAW 264.7 cells and the lower panel represents the COX-2, IκBα and NF-κB expression in the gastric tissue. The relative band intensity of target protein was measured as compared with total protein and β-actin. LPS-induced the phosphorylation of MAPK cascade, whereas pretreatment with the RI reduced the phosphorylation of MAPK cascade. LPS and HCl/EtOH increased the COX-2 expression, kinetic phosphorylation, and degradation of IκBα and phosphorylation of NF-κB. However, pretreatment with the RI notably decreased the COX-2 expression, IκBα phosphorylation, and degradation, NF-κB translocation as related to standard drug ranitidine. # *p* < 0.05 when compared with the control and \* *p* < 0.05 when compared with LPS and HCl/EtOH. Data are expressed as mean ± SEM.


**4. Potential Mechanisms**

Previous studies have proposed several mechanisms in order to explain the possible association between dietary fat and prostate cancer development/progression. Accordingly, growth factor signaling, lipid accumulation, inflammation, and endocrine modulation had been hypothesized to be associated with HFD-induced prostate cancer development and/or progression (Figure 1). Certainly, a more thorough understanding of the possible association between dietary fat and prostate cancer risk requires further inquiry.

**Figure 1.** Scheme of potential mechanisms underlying high-fat diet induced prostate cancer development and/or progression.

### *4.1. Growth Factor Signaling*

Obesity and hyperinsulinemia have been associated with increased amounts of circulating bioactive insulin-like growth factor-I (IGF-I), a growth factor determined to play a pathogenic role in many cancers [81]. Barnard et al. demonstrated that dietary fat reduction combined with a regular exercise intervention in men decreased serum IGF-I and increased serum IGFBP-1 levels, resulting in decreased growth of LNCaP human prostate cancer cells cultured in media containing volunteer serum [14]. The same group showed that LFD-fed mice had significantly slower tumor growth rates, lower levels of serum insulin, tumor IGF-I mRNA expression, and tumor IGFBP-2 immunostaining, and higher levels of serum IGFBP-1, which indicated that IGF-I signaling modulated fat-induced tumor growth in LAPC-4 xenografts [15]. We had previously demonstrated that IGF-I receptor (IGF-IR) mRNA levels were strikingly elevated in HFD-accelerated LNCaP xenografts and that the group having the lowest IGF-IR immunoreactivity tended to have the lowest body mass index in both human normal and prostate cancer epithelia [16]. Kobayashi et al. showed that an LFD reduced the development of prostate cancer in Hi-Myc mouse transgenic model with the suppression of the IGF-AKT pathway, which leads to higher serum IGFBP-1 levels, reduced serum mitogenicity, and lower AKT, GSK3beta, and S6K activities [19].

Several studies have demonstrated that hyperactivation of PI3K-AKT, which is one of the downstream targets for IGF-I signaling, desensitizes tumors to dietary modulations, including calorie restriction and a HFD [23,47]. The PI3K/AKT pathway is naturally inhibited by Pten, which is one of the most frequently lost or mutated tumor suppressor genes in prostate cancer [56]. Partial loss of *PTEN* is observed in 70% of localized prostate cancer, while complete loss thereof is associated with metastatic castration-resistant prostate cancer [56]. *PTEN* inactivation also induces aberrant activation of the PI3K/AKT pathway. As previously mentioned, conditional PTEN knockout produces indolent tumors in mouse prostates. One study that assessed the impact of diet restriction revealed that it does not a ffect a PTEN-null mouse model of prostate cancer but significantly decreases tumor burden in a mouse model of lung cancer lacking constitutive PI3K signaling, which suggests that PI3K signaling is strongly associated with diet-induced cancer progression [23]. Another study involving a GEMM mouse model showed that the loss of both PTEN and the protein tyrosine phosphatase Pypn1, a negative regulator of IGF-IR, enabled the development of a highly invasive prostate tumor, whereas PTEN deficiency alone resulted in tumors that were unresponsive to HFD [47]. Collectively, mechanisms involving PTEN and other related genes may have a higher impact on diet-induced prostate cancer development and progression.

Many other studies have proposed that IGF-I/PI3K/AKT signaling has an impact on diet-induced prostate cancer development and progression [21,28,43]. Therefore, IGF-I/PI3K/AKT signaling has been one of the promising pathways related to HFD-induced prostate cancer development and progression. To determine the impact of treatment, the additive e ffect of IGF-1R inhibition using IGF-IR blockade antibody on 22Rv1 subcutaneous xenografts in SCID mice receiving a HFD (43.3%) or LFD (12.4%) had been investigated [32]. Accordingly, the results showed that the LFD + IGF-1R-Ab group had a significantly smaller mean tumor volume compared to the HF group at day 14 of the intervention. However, no significant di fference in final tumor volumes or final tumor weights had bene observed between the four treatment groups. Therefore, the therapeutic e ffect of IGF-I pathway inhibition remains unknown.

Diet-induced hyperinsulinemia has been shown to accelerate tumor growth in di fferent prostate cancer xenograft models [17,20]. A large prospective survival analysis reported that higher serum C-peptide concentrations, a surrogate of insulin levels, were associated with increased prostate cancer-specific mortality [82]. Insulin and IGF-I are closely related hormones that act on specific tyrosine kinase receptors and elicit the activation of a cascade of intracellular proteins leading to the regulation of gene expression, protein synthesis, cell proliferation or death, and glucose and lipid metabolism. High insulin levels, as well as insulin receptor and IGF-I/IGF-IR axis activation, have been known to be associated with obesity induced cancer progression [83]. Regarding the impact of insulin levels on diet-induced prostate cancer growth, one study involving LAPC-4 xenografts in SCID mice receiving three di fferent diets, NCKD (84% fat), 10% carbohydrate diet (74% fat), or 20% carbohydrate diet (64% fat), proposed that mice receiving a 10% carbohydrate diet had larger tumors than the other groups despite mice receiving a 20% carbohydrate diet having the lowest insulin levels [28]. As such, future studies need to elucidate the relationship between insulin levels and diet-induced prostate cancer carcinogenesis.

In addition, e ffects of di fferent fat sources on the IGF/insulin axis have rarely been discussed and studied. It would be intriguing to know the varying impacts specific fats have on HFD-induced prostate cancer development and progression through growth factor signaling.


paradigm model 104 particularization 102, 113 Patterson, T.C. 2 Paul, A.M. 165, 177 permanent residency visa; Australia 178; Japan 181–2; Singapore 175–6 Pickett, C.L. 75, 77 place of nothingness 92, 94 place reputation 177 pluralism 55–6 policy making 101, 107, 111, 112

policy maker 101, 110, 111, 112 political dialogue and discourse pertaining to education 112 political tactics 112 post-Western 83 Power geometry 147, 150 practical knowledge 105, 108, 109, 110, 111 prescriptive ways of teaching 111 Primary power rule 150 professional identities 106 properties and dimensions 104 process-oriented information 111 Public Sector Nurses and Midwives' Enterprise Agreement, Australia 178 qualitative research 102 quality of teachers 99 ratio of native English to ESL speakers (*see* cultural inclusion/ exclusion) Reid, J.M. 66, 72, 77 relationality 91–4 resiliency (*see* resilient students) resilient students 72 retention; Japan 164, 182–3; nurse 163, 170 retrogression policy; USA 171 Richard-Amato, J. 64, 77 Roesingh, H. 72, 77 rote memorization (*see* significant cultural variables) Ryukoku University 1 Said, E. 87 Scarcella, R.C. 66, 72, 77 Schieffelin, B.B. 65, 77 schooling (*see* cultural variables) Schumann, J. 64, 65, 77 second language socialization (*see* language socialization) Security 144 selective coding 104 self-esteem 106, 107 Semenya, A.H. 76 sense of distance 107

senior high school 100, 107, 108, 110, 111 September 11 viii Shiga, Japan 62 Shih, C.Y. 93 significant cultural variables 66–72; country of origin 67; family 67–9 (see also family structures); first and second languages 69–70; L1 teaching and learning practices 70; rote memorization 70; attention to facts and details 70; teacher-centered instruction 70; focus on grades 70 Singapore 62; dependency ratio celling 174; employer sponsorship 176; foreign worker's levy 174–5, multiculturalism policies 164, 167–9, 171–2; nurse migration 172–6; Nursing Board 174, 176 Smalley, W.A. 63, 77 Smith, B. 77 Social location 147, 150 Social Science Citation Index 84 socialization (*see* language socialization) soft power 4 sojourners 62 Sole responsibility 149 stakeholders 101, 111 stepping stone 163, 165, 174 stepwise migration; Filipino nurses 162–84 subjectivity 90, 92 super-diversity 26 Swan, M. 77 tabunka kyōsei 22, 27, 29, 31, 33, 37, 39n18 Talmy, S. 65, 75, 76 teacher; centered instruction (*see* significant cultural variables); -centered textbook-based grammar translation method 108, 109, 111; educator 100, 101, 110, 111, 112

teachers' resistance 105, 107, 108 teaching and learning (*see* significant cultural variables) Thailand 84 tolerance 45–6, 57, 59 tributary system 82, 93 totalitarianism 4 Trafficking 151 Transnationalism 191, 198, 201, 210–11 Tule Lake Camp 51–2

Uchida, Y. 69, 76 United Nations Commission on Human Rights 35 University 218–20, 222–4 Vertovec, S 25 Vontress, C.E. 63, 78

Westphalia System 89 work-stay immigrants 62 World Englishes 86

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