Transgenic Adenocarcinoma Mouse Prostate Mice Research Articles

Systemic Ablation of Camkk2 Impairs Metastatic Colonization and Improves Insulin Sensitivity in TRAMP Mice: Evidence for Cancer Cell-Extrinsic CAMKK2 Functions in Prostate Cancer.

Despite early studies linking calcium-calmodulin protein kinase kinase 2 (CAMKK2) to prostate cancer cell migration and invasion, the role of CAMKK2 in metastasis in vivo remains unclear. Moreover, while CAMKK2 is known to regulate systemic metabolism, whether CAMKK2’s effects on whole-body metabolism would impact prostate cancer progression and/or related comorbidities is not known. Here, we demonstrate that germline ablation of Camkk2 slows, but does not stop, primary prostate tumorigenesis in the TRansgenic Adenocarcinoma Mouse Prostate (TRAMP) genetic mouse model. Consistent with prior epidemiological reports supporting a link between obesity and prostate cancer aggressiveness, TRAMP mice fed a high-fat diet exhibited a pronounced increase in the colonization of lung metastases. We demonstrated that this effect on the metastatic spread was dependent on CAMKK2. Notably, diet-induced lung metastases exhibited a highly aggressive neuroendocrine phenotype. Concurrently, Camkk2 deletion improved insulin sensitivity in the same mice. Histological analyses revealed that cancer cells were smaller in the TRAMP;Camkk2−/− mice compared to TRAMP;Camkk2+/+ controls. Given the differences in circulating insulin levels, a known regulator of cell growth, we hypothesized that systemic CAMKK2 could promote prostate cancer cell growth and disease progression in part through cancer cell-extrinsic mechanisms. Accordingly, host deletion of Camkk2 impaired the growth of syngeneic murine prostate tumors in vivo, confirming nonautonomous roles for CAMKK2 in prostate cancer. Cancer cell size and mTOR signaling was diminished in tumors propagated in Camkk2-null mice. Together, these data indicate that, in addition to cancer cell-intrinsic roles, CAMKK2 mediates prostate cancer progression via tumor-extrinsic mechanisms. Further, we propose that CAMKK2 inhibition may also help combat common metabolic comorbidities in men with advanced prostate cancer.

RAAV-delivered PTEN therapeutics for prostate cancer

Effective treatments for prostate cancer (PCa) require further development, and previous studies have reported that PTEN and its downstream target CDKN1B are significantly downregulated in PCa cells compared with normal cells. Therefore, modulation of PTEN and CDKN1B expression might be a promising therapeutic approach for PCa treatment. Expression of PTEN and CDKN1B was verified in specimens from PCa patients and transgenic adenocarcinoma mouse prostate (TRAMP) mice. The effect of PTEN on PCa cell migration, apoptosis, and the cell cycle was analyzed in vitro using a wound-healing assay and flow cytometry. We assessed the ability of intraprostatic and intratumoral injections of recombinant adeno-associated virus (rAAV) 9 expressing Pten or Cdkn1b into TRAMP mice and a subcutaneous tumor xenograft mouse model, respectively, to inhibit PCa progression. PTEN and CDKN1B were significantly downregulated in human and mouse PCa samples, and CDKN1B expression correlated positively with PTEN expression. PTEN overexpression significantly inhibited cell migration and cell-cycle progression and promoted apoptosis in PCa cells by decreasing Ccnd1 expression and increasing that of Cdkn1b. Importantly, treatment with the rAAV9.Pten or rAAV9.Cdkn1b extended the lifespan of TRAMP mice and inhibited the growth rate of tumor xenografts by regulating downstream gene expression. Moreover, neoplasia in treated prostates was significantly diminished compared with that in control prostates, and apoptosis was markedly observed in xenografts treated with Pten or Cdkn1b. These data indicate that rAAV-based PTEN/CDKN1B delivery is promising for the development of novel therapeutics for PCa.

RAAV-based and intraprostatically delivered miR-34a therapeutics for efficient inhibition of prostate cancer progression.

At present, there is no effective treatment for prostate cancer (PCa). Previous studies have reported that miR-34a is significantly downregulated in PCa cells; therefore, modulation of miR-34a expression might be a promising therapeutic approach for PCa treatment. To this end, we first verified the downregulation of miR-34a in prostate tumors from a transgenic adenocarcinoma mouse prostate (TRAMP) model. We found that miR-34a overexpression significantly inhibited the cell cycle, viability, and migration of PCa cells by targeting its downstream genes. Next, we tested the concept of intraprostatic injection of rAAV9·pri-miR-34a into 8-week-old TRAMP mice to inhibit PCa progression. We observed that the treatment lowered body weights significantly compared to the control treatment starting at 30 weeks after injection. rAAV9·pri-miR-34a treatment also obviously extended the lifespan of TRAMP mice. Moreover, we confirmed that the neoplasia in the treated prostates was significantly diminished compared to that in the control group. In addition, overexpressed miR-34a downregulated the expression of its target genes. Taken together, our results demonstrated, for the first time, the potential of rAAV-mediated efficient modulation of miR-34a expression in the prostate to inhibit PCa progression by regulating its downstream gene expression.

Host- versus cell-dependent effects of β-Arrestin 1 expression in prostate tumorigenesis

Abstract Prostate cancer (PCa) constitutes a serious health challenge and remains one of the main causes of cancer-related death among men. The more aggressive form of the disease is androgen independent resulting in lack of response to androgen deprivation therapy. The scaffold proteins β-arrestin 1 and 2 (βarr1 and βarr2) which are known to mediate G protein-coupled receptors (GPCRs) desensitization and internalization, were also shown to modulate prostate tumorigenesis. βarr1 is overexpressed (~4 fold) in PCa cells relative to βarr2. In this study, we investigate the effect of β-arrestins expression in prostate tumorigenesis using in-vivo xenografts and autochthonous transgenic adenocarcinoma mouse prostate (TRAMP) model deficient in β-arrestins expression. Depletion of βarr1 in TRAMP mice (TRAMP/βarr1−/−) increased PCa growth and decreased overall survival, relative to TRAMP and TRAMP/βarr2−/− animals. Tumors from TRAMP/βarr1−/− mice displayed increase androgen receptor (AR), but decrease prostate specific antigen (PSA) expression. In contrast, depletion of βarr1 in MDA PCa 2b cells (MDA PCa 2b-βarr1−/−) decreased cell proliferation, wound closure and anchorage independent cell growth compared to wild type MDA PCa 2b and MDA PCa 2b-βarr2−/− cells. Nude mice xenografts of MDA PCa 2b-βarr1−/− cells also showed significant decrease in tumor growth. Interestingly, tumor lysates from MDA PCa 2b-βarr1−/− xenografts exhibited decrease AR and increase PSA expression, relative to control tumors. Altogether, the data indicate that βarr1 modulates AR/PSA signaling to regulate prostate cancer aggressiveness. However, the effect of βarr1 is context-sensitive depending on its expression in the host relative to the tumor cells.

Anticancer effect of icaritin on prostate cancer via regulating miR-381-3p and its target gene UBE2C.

Prostate cancer (PCa) is one of the most common health‐related issues in the male individuals of western countries. Icaritin (ICT) is a traditional Chinese herbal medicine that exhibits antitumor efficacy in variety of cancers including PCa. However, the precise function and detailed molecular mechanism of ICT in the regression of PCa remain unclear. Ubiquitin‐conjugating enzyme E2C (UBE2C) is an anaphase‐promoting complex/cyclosome (APC/C)‐specific ubiquitin conjugating enzyme, which acts as an oncogene in PCa progression. The function of ICT in PCa was investigated in transgenic adenocarcinoma mouse prostate (TRAMP) mice using survival analysis, hematoxylin and eosin (HE) staining, TUNEL assay, and immunohistochemistry and in human PCa cell lines using various molecular techniques and functional assays including plasmid construction and transfection. Bioinformatic analyses were performed to identify the interaction between miRNA and UBE2C via the TargetScan algorithm. We demonstrated that ICT inhibited the development and progression of PCa in TRAMP mice by improving the survival rate and tumor differentiation. Furthermore, we found that ICT could significantly inhibit cell proliferation and invasion and induce apoptosis in PCa cells. Consistently, downregulation of UBE2C suppressed the proliferation and invasion of PCa cells. Moreover, a luciferase reporter assay confirmed that UBE2C was a direct target of miR‐381‐3p. Meanwhile, ICT simultaneously downregulated UBE2C expression and upregulated miR‐381‐3p levels in human PCa cells. Altogether, our findings provide a strong rationale for the clinical application of ICT as a potential oncotherapeutic agent against PCa via a novel molecular mechanism of regulating the miR‐381‐3p/UBE2C pathway.

P21 and P27 promote tumorigenesis and progression via cell cycle acceleration in seminal vesicles of TRAMP mice.

Transgenic adenocarcinoma mouse prostate (TRAMP) model is established to mimic human prostate cancer progression, where seminal vesicle lesions often occur and has been described as phyllodes-like epithelial-stromal tumors. However, the molecular mechanism regulating tumorigenesis and progression in seminal vesicles of TRAMP mice remains largely unknown. In this study, C57BL/6 TRAMP mice were found to have a significantly shorter lifespan than wild-type (WT) mice and all of the seminal vesicles were markedly increased in size and weight with age from 24 weeks exhibiting a clearly papillary-phyllode pattern, though no obvious difference was observed in multiple organs including heart, liver, spleen, lungs, kidneys, testicles and bone between TRAMP and WT mice, and less than 10% of TRAMP mice developed prostate tumors. Western blotting showed Cyclin (CCN) B1 and CCND1 were remarkably overexpressed in seminal vesicle tumors of TRAMP mice at 24 weeks of age and increased with age till the end of trial, which was confirmed by Immunohistochemistry (IHC). P21 and P27 were also significantly augmented, whereas P53 and phosphorylated P53 (p-P53) were constantly expressed in normal controls and P53 did not appear to be mutated. Not only cyclin-dependent kinase (CDK) 1 and phosphorylated forkhead box protein (FOX) O1 but also CDK4, CDK6 and phosphorylated retinoblastoma-associated protein (RB) had similar increase trends, so did epidermal growth factor receptor (EGFR), AKT serine/threonine kinase (AKT), and their respective phosphorylation levels. Signal transducer and activator of transcription (STAT) 3, p-STAT3, enhancer of zeste homolog 2 (EZH2) and EZH2 mediated trimethylation of histone H3 lysine 27 (H3K27me3) were considerably elevated, too. Taken together, this finding suggests P21 and P27 promote carcinogenesis and development in seminal vesicles of TRAMP mice via accelerating cell cycle progression, in which oncogenic transformation of P21 and P27 might be through regulation of EGFR-AKT signaling.

Maternal High-Fat Diet Promotes the Development and Progression of Prostate Cancer in Transgenic Adenocarcinoma Mouse Prostate Offspring

Background/Aims: We aim to investigate the impact of maternal high fat diet (HFD) on the development and progression of prostate cancer (PCa) in transgenic adenocarcinoma mouse prostate (TRAMP) offspring. Methods: The TRAMP model was used, and divided into maternal HFD group and normal diet (ND) group in the present study. Each group contained 36 TRAMP mice. Serum levels of leptin, adiponectin, interleukin (IL) -1α, IL-1β, IL-6, tumor necrosis factor-α and monocyte chemotactic protein-1 were measured by the 20th, 24th and 28th week old through ProcartaPlex Multiplex Immunoassay. Body fat ratio was measured by MiniQMR. Tumor formation rate was measured through hematoxylin and eosin (H&E) staining, and mortality rate was measured meantime. Western blot was applied to determine the levels of Protein Kinase B (Akt) and Phosphatase and tensin homolog (PTEN). Results: The mortality rate of maternal HFD group was significantly higher than that of ND group (P = 0.046). The tumor formation rate was significantly higher in maternal HFD group than in ND group only in 20th week subgroup (P = 0.040). A significant increase of leptin was seen in maternal HFD 20th and 24th week subgroups (P = 0.001 and < 0.001, respectively) and a decrease of adiponectin was seen in maternal HFD 20th and 28th week subgroups (P =0.006 and < 0.001, respectively). Besides, an activated phos-Akt (P-Akt) and deactivated PTEN were observed in maternal HFD group. Conclusions: Maternal HFD could increase the standard serum leptin level, inhibit the expression of PTEN protein, promote P-Akt protein expression, activate the PI3K/Akt pathway, and ultimately promote the development and progression of PCa in TRAMP offspring.

A novel anticancer agent icaritin inhibited proinflammatory cytokines in TRAMP mice.

We aimed to investigate whether icaritin (ICT) would inhibit serum proinflammatory cytokines and postpone prostate cancer (PCa) development and progression in both normal diet and high-fat diet (HFD) transgenic adenocarcinoma mouse prostate (TRAMP) mice. TRAMP mice were randomly divided into four groups: normal diet with/without ICT group and HFD with/without ICT group. Each TRAMP mouse received intraperitoneal injection of ICT solution at the dose of 30mg/kg 5 times per week. ICT treatment could significantly increase the survival when compared with those in normal diet group (P=0.015, log-rank test) and HFD group (P=0.009, log-rank test). Proinflammatory cytokine levels, including IL-1α, IL-1β, IL-6, and TNF-α, were decreased more or less in ICT-treated TRAMP mice. Moreover, significant higher inflammation scores were detected in normal diet group and HFD group compared with their relevant ICT treatment groups (P=0.026 and P=0.006, respectively). Meanwhile, the incidences of well-differentiated tumor tissue in two ICT treatment groups (39.13 and 31.82%) were moderately higher than control groups (29.41 and 20.00%, respectively), though no significant difference was observed. Taken together, our findings indicate that ICT could inhibit the development and progression of PCa in TRAMP mice via inhibiting proinflammatory cytokines.

669. rAAV-Based and Intraprostatically Delivered miR-34a Therapeutics for Efficient Inhibition of Prostate Cancer Progression

Prostate cancer (PCa) is the second most common diagnosed cancer and the fifth cause of cancer-related mortality for males worldwide. At present, there is no effective treatment for PCa. Towards further understanding molecular mechanism and developing therapeutics for PCa, we investigated the role of miR34a in PCa progression. Previous studies have reported that miR-34a was significantly downregulated in PCa cells; therefore, modulation of miR34a expression might be a promising therapeutic approach for PCa treatment. To this end, we first verified the downregulation of miR34a in prostate tumor from transgenic adenocarcinoma mouse prostate (TRAMP) model. We found that overexpression of miR-34a could significantly inhibit the cell cycle of PC3 cells (a human PCa cell line) by prolonging G1 and shortening S phases through targeting cyclin D1 (CCND1). To investigate if in vivo gene delivery of pri-miR34a to the prostates of TRAMP mice can inhibit PCa progression, we opted to screen 12 serotypes of rAAVs, an efficient and safe in vivo gene delivery platform with serotype dependent tissue tropisms for efficient prostate in vivo and PCa cell in vitro transduction. Among several leading candidate vectors (i.e. AAV6.2, AAV7 and AAV9) identified, we first tested the concept of intraprostatic injection of rAAV9 pri -miR34a (4×1011 GCs/prostate) to 8-week old TRAMP mice for inhibition of PCa progression. We observed that the treatment lowered body weights significantly (p < 0.05) as compared to the control group starting from 24 weeks after injection, likely resulted from the higher tumor burden in the control group. rAAV9.pri -miR34a treatment also significantly extended the lifespan of TRAMP mice (p < 0.05). Moreover, we confirmed that the proliferation and neoplasia in the treated prostates were significantly diminished when compared to those in the control group. Currently, the experiments are under the way to elucidate the molecular mechanism of overexpressed miR34a to slow down PCa progression. Taken together, our results demonstrated, for the first time, the potentials of rAAV-mediated efficient modulation of miRNA expression in the prostate for inhibiting PCa progression and studying molecular mechanisms in PCa development.

Benzyl Isothiocyanate Inhibits Prostate Cancer Development in the Transgenic Adenocarcinoma Mouse Prostate (TRAMP) Model, Which Is Associated with the Induction of Cell Cycle G1 Arrest.

Benzyl isothiocyanate (BITC) is a hydrolysis product of glucotropaeolin, a compound found in cruciferous vegetables, and has been shown to have anti-tumor properties. In the present study, we investigated whether BITC inhibits the development of prostate cancer in the transgenic adenocarcinoma mouse prostate (TRAMP) mice. Five-week old, male TRAMP mice and their nontransgenic littermates were gavage-fed with 0, 5, or 10 mg/kg of BITC every day for 19 weeks. The weight of the genitourinary tract increased markedly in TRAMP mice and this increase was suppressed significantly by BITC feeding. H and E staining of the dorsolateral lobes of the prostate demonstrated that well-differentiated carcinoma (WDC) was a predominant feature in the TRAMP mice. The number of lobes with WDC was reduced by BITC feeding while that of lobes with prostatic intraepithelial neoplasia was increased. BITC feeding reduced the number of cells expressing Ki67 (a proliferation marker), cyclin A, cyclin D1, and cyclin-dependent kinase (CDK)2 in the prostatic tissue. In vitro cell culture results revealed that BITC decreased DNA synthesis, as well as CDK2 and CDK4 activity in TRAMP-C2 mouse prostate cancer cells. These results indicate that inhibition of cell cycle progression contributes to the inhibition of prostate cancer development in TRAMP mice treated with BITC.

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.

Insulin-like growth factor 1 related pathways and high-fat diet promotion of transgenic adenocarcinoma mouse prostate (TRAMP) cancer progression

IntroductionWe aimed to investigate the role of IGF-1 related pathway in high-fat diet (HFD) promotion of TRAMP mouse PCa progression. MethodsTRAMP mice were randomly divided into two groups: HFD group and normal diet group. TRAMP mice of both groups were sacrificed and sampled on the 20th, 24th and 28th week, respectively. Serum levels of insulin, IGF-1 and IGF-2 were tested by ELISA. Prostate tissue of TRAMP mice was used for both HE staining and immunohistochemical staining of IGF-1 related pathway proteins, including IGF-1Rα, IGF-1Rβ, IGFBPs and AKT. ResultsThe mortality of TRAMP mice from HFD group was significantly higher than that of normal diet group (23.81% and 7.14%, P=0.035). The tumor incidence of HFD TRAMP mice at 20th week was significantly higher than normal diet group (78.57% and 35.71%, P=0.022). Serum IGF-1 level of HFD TRAMP mice was significantly higher than that of normal diet TRAMP mice. Serum IGF-1 level tended to increase with HFD TRAMP mice's age. HFD TRAMP mice had higher positive staining rate of IGF-1Rα, IGF-1Rβ, IGFBP3 and Akt than normal diet TRAMP mice. ConclusionsIGF-1 related pathway played an important role in high-fat diet promotion of TRAMP mouse PCa development and progression.

Proinflammatory cytokines in prostate cancer development and progression promoted by high-fat diet.

Background. We aimed to examine whether proinflammatory cytokines participated in prostate cancer (PCa) development and progression promoted by high-fat diet (HFD). Methods. TRAMP (transgenic adenocarcinoma mouse prostate) mice were randomly divided into two groups: normal diet group and HFD group. Mortality rate and tumor formation rate were examined. TRAMP mice were sacrificed and sampled on the 20th, 24th, and 28th week, respectively. Levels of proinflammatory cytokines, including IL-1α, IL-1β, IL-6, and TNF-α, were tested by FlowCytomix. Prostate tissue of TRAMP mice was used for histology study. Results. A total of 13 deaths of TRAMP mice were observed, among which 3 (8.33%) were from the normal diet group and 10 (27.78%) from the HFD group. The mortality rate of TRAMP mice from HFD group was significantly higher than that of normal diet group (P = 0.032). Tumor formation rate at 20th week of age of HFD group was significantly higher than that of normal diet group (P = 0.045). Proinflammatory cytokines levels, including IL-1α, IL-1β, IL-6, and TNF-α, were significantly higher in HFD TRAMP mice. Conclusions. HFD could promote TRAMP mouse PCa development and progression with elevated proinflammatory cytokines levels. Proinflammatory cytokines could contribute to PCa development and progression promoted by HFD.

Adoptive Transfer of Myeloid-Derived Suppressor Cells and T Cells in a Prostate Cancer Model.

The adoptive transfer of immune cells for cancer, chronic infection, and autoimmunity is an emerging field that has shown promise in recent trials. The transgenic adenocarcinoma mouse prostate (TRAMP) is a classical mouse model of prostate cancer (PCa) and TRAMP cell lines were derived from a TRAMP mouse tumor. TRAMP-C2 is tumorigenic when subcutaneously (s.c.) grafted into syngeneic C57BL/6 host mice (Foster et al., 1997). This protocol will describe the adoptive transfer of purified CD11b+Gr1+ double positive (DP) myeloid-derived suppressor cells (MDSC) and CD3+ T cells in the TRAMP-C2 prostate cancer mouse model in order to establish the intrinsic functionality of these immune cells and to determine their role in tumorigenesis in vivo (Yan et al., 2014).

Androgen Ablation Mitigates Defect of B Cells to a Prostate Cancer and Increase Survival Rate of Tramp Mice

Androgen ablation is the most commonly used therapy for prostate cancer. However, the effects of androgen ablation on immune system, especially B cell distribution are not well understood. We have used transgenic adenocarcinoma mouse prostate (TRAMP) mice to characterize the B cell distribution in periphery blood and spleen upon androgen ablation. We found a decrease of the B cell population in wild type TRAMP mice compared to normal wild type mice. Furthermore, the B cells increased when in castrated TRAMP mice compared to the wild type TRAMP mice. Interestingly, we found an increase in immature B cells in the spleen of castrated TRAMP mice, which might be due to the resistance to apoptosis during B cell maturation. Our data suggest that androgen ablation might play an important role in the regulation of B cell tolerance.

Abstract 191: Methylseleninic acid super-activates p53 senescence axis as a preventive barrier to prostate tumorigenesis driven by Pten deficiency in vivo.

Abstract Prostate cancer (PCa) arises from progression of pre-invasive lesions such as prostatic intraepithelial neoplasia (PIN) to adenocarcinoma and metastatic disease. Due to the very long latency of lesion progression, chemoprevention of prostate adenocarcinogenesis is recognized as a plausible and essential approach to win the war against PCa. Whereas the results from recent clinical trials (SWOG 9917 and SELECT) did not support the protective function for seleno-methionine (SeMet) supplement in healthy men with or without high grade PIN, we and others have shown that supra-nutritional supplement of methylseleninic acid (MSeA), which differs, both chemically and metabolically, from SeMet, suppressed tumor growth in human prostate cancer xenografts, and in the transgenic adenocarcinoma mouse prostate (TRAMP) model. However, the former models did not mimic primary prevention, and the TRAMP mice vastly differ from the etiology and adenocarcinogenesis nature of the human prostate cancers. Therefore, a mouse model that closely recapitulates the clinic pathological features of human prostate cancer will be essential and necessary to predict the preventive efficacy and mechanisms of MSeA in men. As the loss of tumor suppressor gene Pten (phosphatase and tensin homolog deleted on chromosome 10) plays a causal role in human prostate cancers, the prostate epithelial-specific Pten-knockout mouse is such a preclinical model of choice. Here we utilized Probasin-Cre (Pb-Cre) transgenic mice expressing Cre to delete Pten in prostate epithelium to investigate whether administration of MSeA inhibited prostate tumorigenesis. We treated Pten-knockout and age-matched wild type male mice from 8 weeks of age with water or MSeA at a dose of 3 mg/kg body weight five times a week (Monday through Friday) for 27 weeks and sacrificed them for analyses. Our results show that MSeA significantly suppressed prostate tumorigenesis as evidenced by (1) suppression of tumor progression to high grade PIN or/and adenocarcinoma; (2) a 50% reduction in prostate tumor weight (P&amp;lt;0.01); (3) a significant reduction in cellular proliferation determined by ki67 immunostaining (P&amp;lt;0.01); and (4) attenuation of androgen receptor (AR) signaling. Mechanistically, we found that MSeA induced a super-activation of p53, p21 and cellular senescence. Because intact p53 signaling is preserved in most early prostate lesions, our findings provide compelling rationale to consider MSeA as a bioactive dietary supplement to activate p53-p21 mediated senescence as a barrier to prevent PIN from progressing to advanced prostate cancer. Citation Format: Lei Wang, Hua Xiong, Fengxia Wu, Tao Lin, Junxuan Lu, Yibin Deng. Methylseleninic acid super-activates p53 senescence axis as a preventive barrier to prostate tumorigenesis driven by Pten deficiency in vivo. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 191. doi:10.1158/1538-7445.AM2013-191

Effects of dietary high fat on prostate intraepithelial neoplasia in TRAMP mice

Increased fat intake is known to be a major cause of prostate cancer. In this study, we investigated the effect of dietary high fat on prostate intraepithelial neoplasia using transgenic adenocarcinoma mouse prostate (TRAMP) mice. Six-week-old male TRAMP mice were fed AIN93G (control group, 4.0 kcal/kg, n=6) and AIN93G-HFD (experimental group, 4.8 kcal/kg, n=7) for 10 weeks. Prostate histopathology, urogenital tract (UGT) weight, epididymal white adipose tissue weight, argyrophilic nucleolar organizer regions (AgNORs) counts, and serum leptin levels were examined. AIN93G-HFD fed group showed progressed neoplastic lesions in the prostate (P<0.05) compared to AIN93G fed group. AIN93G-HFD intake resulted in a increase in the weight of UGT (P<0.05) and epididymal white adipose tissue. The number of Ag-NOR positive dots significantly increased in each prostate lobe and final serum leptin levels in AIN93G-HFD fed group were about twice those of AIN93G fed group (P<0.05). Dietary high fat was related to the prostate cancer progression in the early stage of TRAMP mice and increased serum leptin levels, suggesting that the regulation of dietary components could delay the progression of prostate cancer.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Abstract 609: Benzyl isothiocyanate inhibits prostate cancer development in the transgenic adenocarcinoma mouse prostate model

Abstract Benzyl isothiocyanate (BITC) is a hydrolysis product of glucotropaeolin, a compound found in cruciferous vegetables, and has also been shown to have anti-tumor properties. In the present study, we attempted to determine whether BITC inhibits the development of prostate cancer using the transgenic adenocarcinoma mouse prostate (TRAMP) model. Male TRAMP mice and their nontransgenic (normal) littermates at 5 wk of age were randomly divided into control and BITC-treatment groups and gavage-fed with 0 (vehicle), 5, or 10 mg/kg of BITC every other day. At the time of sacrifice (24 wk of age), BITC did not affect body weight of normal or transgenic animals. The genitourinary tract weight of TRAMP mice was increased markedly as compared to normal mice, and this increase was suppressed significantly via the oral administration of 5 or 10 mg/kg of BITC. H&amp;E staining of the dorsolateral lobes of the prostate demonstrated that well-differentiated carcinoma (WDC) was a predominant feature in the 24 week old vehicle-fed TRAMP mice, whereas number of lobes with WDC was reduced and the number of lobes with prostatic intraepithelial neoplasia was increased by feeding with 5 or 10 mg/kg of BITC. BITC feeding reduced the number of cells expressing the Ki67 (a proliferation marker) in the prostatic tissue. Additionally, BITC feeding reduced the expression of cyclin E, cyclin D1, cyclin A, and cyclin-dependent kinase (CDK)2. Our in vitro cell culture results revealed that BITC decreased DNA synthesis and CDK2 activity in TRAMP-C2 mouse prostate cancer cells. However, BITC did not affect apoptosis either in transgenic mice in vivo or in TRAMP-C2 cells in vitro. These results indicate that inhibition of cell cycle progression contributes to the inhibition of prostate cancer development in animals treated with BITC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 609. doi:1538-7445.AM2012-609

Abstract 1998: Inhibition of hedgehog signaling in prostate cancer by extracts of Sutherlandia

Abstract Prostate cancer possesses long latency periods and is responsive to dietary mediators, making it a target for phytochemoprevention. Many botanical compounds that have been proposed to prevent cancer may potentially work via inhibition of the hedgehog signaling pathway. Here we investigated the potential of Sutherlandia frutescens (also called Lessertia and “cancer bush” in South Africa) to inhibit hedgehog signaling. We hypothesize that the anti-cancer effects of Sutherlandia are due to its inhibition of hedgehog signaling pathway activity. Methods: We evaluated Sutherlandia's effects of growth inhibition in vitro both in the human prostate cancer cell line PC3 and mouse prostate cancer cell line TRAMP-C2 by exposing the cells for 72hrs to plant extracts before protein concentrations were measured to evaluate inhibition of growth. To determine hedgehog pathway inhibitory activity, we treated two different cell lines (an NIH3T3 cell line and a TRAMPC2 cell line) stably transfected with a firefly luciferase reporter having Gli response elements in the firefly luciferase promoter. After 48hr exposure to treatment with multiple doses of Sutherlandia, a firefly substrate was added to the cell lysate and the luciferase signal was measured using a Biotek Synergy plate reader. Finally, Sutherlandia was incorporated into a diet and fed to TRAMP (Transgenic Adenocarcinoma Mouse Prostate) mice to examine whether the plant can delay or even inhibit prostate cancer incidence in the TRAMPmouse model. Results: Sutherlandia extracts inhibited growth of both PC3 and TRAMPC2 cells. In addition, hedgehog signaling was inhibited by Sutherlandia in both NIH3T3 and TRAMPC2 reporter cells. Interestingly, in vivo the lowest concentration of Sutherlandia diet had the greatest effect on inhibition of poorly differentiated adenocarcinoma in the TRAMP mice. Conclusions: Sutherlandia's inhibition of prostate cancer growth may be via inhibition of hedgehog signaling. Future work to identify in Sutherlandia the active compound having this effect, and the ideal concentration for use in vivo may lead to a means whereby dietary intervention for prostate cancer prevention and/or treatment is possible. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1998. doi:1538-7445.AM2012-1998