Female Apc Min Research Articles

Leucine Supplementation Exacerbates Morbidity in Male but Not Female Mice with Colorectal Cancer-Induced Cachexia.

Cancer cachexia (CC) is a multifactorial wasting syndrome characterized by a significant loss in lean and/or fat mass and represents a leading cause of mortality in cancer patients. Nutraceutical treatments have been proposed as a potential treatment strategy to mitigate cachexia-induced muscle wasting. However, contradictory findings warrant further investigation. The purpose of this study was to determine the effects of leucine supplementation on skeletal muscle in male and female ApcMin/+ mice (APC). APC mice and their wild-type (WT) littermates were given normal drinking water or 1.5% leucine-supplemented water (n = 4-10/group/sex). We measured the gene expression of regulators of inflammation, protein balance, and myogenesis. Leucine treatment lowered survival rates, body mass, and muscle mass in males, while in females, it had no effect on body or muscle mass. Leucine treatment altered inflammatory gene expression by lowering Il1b 87% in the APC group and decreasing Tnfa 92% in both WT and APC males, while it had no effect in females (p < 0.05). Leucine had no effect on regulators of protein balance and myogenesis in either sex. We demonstrated that leucine exacerbates moribundity in males and is not sufficient for mitigating muscle or fat loss during CC in either sex in the ApcMin/+ mouse.

Simulated galactic cosmic radiation (GCR)-induced expression of Spp1 coincide with mammary ductal cell proliferation and preneoplastic changes in ApcMin/+ mouse

Female astronauts inevitably exposed to galactic cosmic radiation (GCR) are considered at a greater risk for mammary cancer development. The purpose of this study is to assess the status of mammary cancer-associated preneoplasia markers after GCR and γ-ray irradiation using a mouse model of human mammary cancer. Female ApcMin/+ mice were irradiated to 50 cGy of either γ-ray (137Cs) or full-spectrum simulated galactic cosmic radiation (GCR) (33-beam), and at 110 – 120 days post-irradiation mice were euthanized, and normal-appearing mammary tissues were analyzed for histological and molecular markers of preneoplasia. Whole-mount staining, hematoxylin and eosin-based histological assessment, and Cyclin D1 immunohistochemistry (IHC) were performed to analyze ductal outgrowth and cell proliferation. Additionally, mRNA expression of known mammary preneoplasia markers (Muc1, Exo1, Foxm1, Depdc1a, Nusap1, Spp1, and Rrm2) was analyzed using qPCR, and their respective protein expression was validated using immunohistochemistry. A significant increase in ductal outgrowth and cell proliferation in mammary tissues of GCR-irradiated mice was noted which indicates a higher risk of mammary cancer, relative to γ-rays. Increased mRNA and protein expression of Spp1 was observed in the GCR group, relative to γ-rays. This study demonstrates the plausibility of Spp1 as a preneoplasia marker in the early detection of mammary cancer after space radiation exposure.

Translocation of Helicobacter hepaticus synergizes with myeloid-derived suppressor cells and contributes to breast carcinogenesis

ABSTRACT Microbial dysbiosis plays an important role in the development of intestinal diseases. Recent studies suggest a link between intestinal bacteria and mammary cancer. Here, we report that female ApcMin/+ mice infected with Helicobacter hepaticus exhibited an increased mammary and small/large intestine tumor burden compared with uninfected littermates. H. hepaticus DNA was detected in small/large intestine, mammary tumors, and adjacent lymph nodes, suggesting a migration pathway. CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs) infiltrated and expressed high levels of Wnts, likely enhancing tumorigenesis through activation of Wnt/β-catenin pathway. Our previous studies indicated that histidine decarboxylase (Hdc) marks a population of myeloid-biased hematopoietic stem cells and granulocytic MDSCs. Cytokines/chemokines secreted by IL-17-expressing mast cells and tumor tissues promoted Hdc+ MDSCs expansion and trafficking toward mammary tumors. Adoptive transfer of MDSCs isolated from H. hepaticus-infected mice increased MDSCs frequencies in peripheral blood, mesenteric lymph nodes, mammary gland, and lymph nodes in recipient ApcMin/+ mice. The adoptive transfer of H. hepaticus primed MDSCs also increased the size and number of mammary tumors. Our results demonstrate that H. hepaticus can translocate from the intestine to mammary tissues to promote mammary tumorigenesis with MDSCs. Targeting bacteria and MDSCs may be useful for the prevention and therapy of extraintestinal cancers. Abbreviations: Helicobacter hepaticus, Hh; myeloid-derived suppressor cell, MDSC; histidine decarboxylase, Hdc; Breast cancer, BC; T regulatory, TR; inflammatory bowel disease, IBD; fluorescence in situ hybridization, FISH; myeloid-biased hematopoietic stem cells, MB-HSCs; granulocytic MDSCs, PMN-MDSCs; Lipopolysaccharide, LPS; Toll-like receptors, TLRs; Mast cells, MCs; Granulocyte-macrophage colony-stimulating factor, GM-CSF; epithelial–mesenchymal transition, EMT; Intestinal epithelial cells, IECs.

Sex-dependent lifespan extension of Apc Min/+ FAP mice by chronic mTOR inhibition.

Apc Min/+ mice model familial adenomatous polyposis (FAP), a disease that causes numerous colon polyps leading to colorectal cancer. We previously showed that chronic treatment of Apc Min/+ females with the anti-aging drug, rapamycin, restored a normal lifespan through reduced polyposis and anemia prevention. Lifespan extension by chronic rapamycin in wildtype UM-HET3 mice is sex-dependent with females gaining the most benefit. Whether Apc Min/+ mice have a similar sex-dependent response to chronic mTOR inhibition is not known. To address this knowledge gap and gain deeper insight into how chronic mTOR inhibition prevents intestinal polyposis, we compared male and female Apc Min/+ mice responses to chronic treatment with a rapamycin-containing diet. Animals were fed a diet containing either 42 ppm microencapsulate rapamycin or empty capsules, one group was used to determine lifespan and a second group with similar treatment was harvested at 16 weeks of age for cross-sectional studies. We found that the survival of males is greater than females in this setting (P < 0.0197). To explore the potential basis for this difference we analyzed factors affected by chronic rapamycin. Immunoblot assays showed that males and females exhibited approximately the same level of mTORC1 inhibition using phosphorylation of ribosomal protein S6 (rpS6) as an indirect measure. Immunohistochemistry assays of rpS6 phosphorylation showed that rapamycin reduction of mTORC1 activity was on the same level, with the most prominent difference being in intestinal crypt Paneth cells in both sexes. Chronic rapamycin also reduced crypt depths in both male and female Apc Min/+ mice (P < 0.0001), consistent with reduced crypt epithelial cell proliferation. Finally, chronic rapamycin prevented anemia equally in males and females. In males and females, these findings link rapamycin-mediated intestinal polyposis prevention with mTORC1 inhibition in Paneth cells and concomitant reduced epithelial cell proliferation.

Abstract 671: mTORC1 suppression in Paneth cells prevents tumors in a mouse model of intestinal cancer

Abstract The mechanistic (or mammalian) target of rapamycin, mTOR, is a highly conserved PI3K-related kinase that regulates cell growth, proliferation, survival, transcription, and protein synthesis. It forms two different complexes, mTOR complex-1 (mTORC1) and -2 (mTORC2). Rapamycin is an allosteric inhibitor specific to mTORC1 and extends life and health span with chronic use. Previous research from our lab shows that an enteric release formulation of rapamycin, eRapa, enhances the lifespan of mice mutated for adenomatous polyposis coli (Apc) tumor suppressor (ApcMin/+ mice), which normally develop intestinal cancer. These mice model familial adenomatous polyposis (FAP) in humans. eRapa restored a normal (and in 60% of the mice longer) life span in female ApcMin/+ mice. Mutations in Apc, a part of the Wnt/β-catenin pathway, accelerate the initiation of the adeno-carcinoma in FAP, resulting in numerous colorectal polyps at a young age, and if left untreated these polyps progress to colorectal cancer.eRapa treatment prevents polyposis in ApcMin/+ mice but the precise mechanism of action remains to be determined. We used a cross sectional and survival approach to test the preventive effects of eRapa and gain mechanistic insights. Four-week-old male and female animals were put on a diet containing either 42 ppm of eRapa or empty microcapsules. A subset of the animals was sacrificed to harvest tissue for analysis at 16 weeks of age and the rest were allowed to live out their lifespans.eRapa prevented polyposis in the small intestine of ApcMin/+ mice with only a few to no tumors in both males and females. In addition to adenomas in the intestine, ApcMin/+ mice also suffer from severe anemia. Hematocrits from the animals showed anemia in the control mice, however, eRapa treated animals did not have anemia. There was a reduction in phosphorylation of ribosomal protein S6 in the small intestine tissue, showing suppression of mTORC1 activity with eRapa. Histological analysis revealed that this suppression occurred in the Paneth cells of the small intestinal crypt. The Paneth cells, along with the stem cells at the base of the crypt form a niche and signaling between this niche maintains homeostasis in the crypt. Although the polyps are believed to originate from stem cells, our results suggest involvement of Paneth cells in tumor prevention perhaps by signaling changes in the niche. These are novel effects of rapamycin and help define its mechanisms of cancer prevention. Citation Format: Manish Parihar, Sherry G. Dodds, Paul Hasty, Zelton Dave Sharp. mTORC1 suppression in Paneth cells prevents tumors in a mouse model of intestinal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 671.

Protons Show Greater Relative Biological Effectiveness for Mammary Tumorigenesis with Higher ERα- and HER2-Positive Tumors Relative to γ-rays in APCMin/+ Mice

Exposure to ionizing radiation increases risk of breast cancer. Although proton radiation is encountered in outer space and in medicine, we do not fully understand breast cancer risks from protons owing to limited invivo data. The purpose of this study was to comparatively assess the effects of γ-rays and protons on mammary tumorigenesis in APCMin/+ mice. Female APCMin/+ mice were exposed to 1 GeV protons (1.88 or 4.71 Gy) and 137Cs γ-rays (2 or 5 Gy). Mice were euthanized 100 to 110 days after irradiation, at which point mammary tumors were scored, tumor grades were assessed, and relative biological effectiveness was calculated. Molecular phenotypes were determined by assessing estrogen receptor α (ERα) and human epidermal growth factor receptor 2 (HER2) status. ERα downstream signaling was assessed by immunohistochemistry. Exposure to proton radiation led to increased mammary tumor frequency at both proton radiation doses compared with γ-rays. The calculated relative biological effectiveness for proton radiation-induced mammary tumorigenesis was 3.11 for all tumors and >5 for malignant tumors relative to γ-rays. Tumor frequency per unit of radiation was higher at the lower dose, suggesting a saturation effect at the higher dose. Protons induced more adenocarcinomas relative to γ-rays, and proton-induced tumors show greater ERα and HER2 positivity and higher activation of the ERα downstream PI3K/Akt and cyclin D1 pathways relative to γ-rays. Our data demonstrate that protons pose a higher risk of mammary tumorigenesis relative to γ-rays. We also show that proton radiation-induced tumors in APCMin/+ mice are ERα- and HER2-positive, which is consistent with our previous data on radiation-induced estrogenic response in wild-type mice. Although this study establishes APCMin/+ as a model with adequate signal-to-noise ratio for space radiation-induced mammary tumorigenesis, further studies will be required to address the uncertainties in space radiation-induced breast cancer risk estimation.

The Effect of Estradiol Administration on Muscle Mass Loss and Cachexia Progression in Female Apc Min/+ Mice.

Cancer cachexia is a multifactorial muscle wasting condition characterized by severe body weight and muscle mass loss which is secondary to chronic disease. The mechanistic examination of cachexia has predominately focused on the male phenotype and created significant gaps in understanding cachexia progression in the female. Female hypogonadism can accompany cancer cachexia and is characterized by reduced circulating 17ß-estradiol and uterine atrophy. Estrogen has known functions in skeletal muscle homeostasis involving the regulation of muscle protein turnover, cellular stressors, and oxidative metabolism. However, 17ß-estradiol's ability to regulate cachexia progression in the female is not known. The purpose of this study was to determine the effect of gonadal function and estradiol administration on muscle mass loss and cachexia progression in female ApcMin/+ mice.Methods: Female C57BL/6 (B6; N = 82) and ApcMin/+ (MIN; N = 88) mice were used in two separate experiments. In experiment 1, mice were sacrificed at either 12 (N = 20) or 20 (N = 41) weeks of age. Body weight and estrous cycle presence was determined weekly. In experiment 2, B6 and MIN mice were randomly allocated to: Control (N = 17), received E2 pellet (E2, N = 18), ovariectomy surgery (OVX; N = 19) or ovariectomy surgery with E2 pellet (OVX + E2; N = 21). 17ß-estradiol was administered through an implanted slow-releasing pellet (0.1 mg). In estrogen and ovariectomy experiments, food intake, and functional outcomes were recorded 1 week prior to sacrifice.Results: We report that E2 administration prevented body weight loss, muscle mass loss, cage inactivity, and grip strength loss associated with cachexia. In skeletal muscle, E2 reduced skeletal muscle AMPK phosphorylation, improved mTORC1 signaling, and prevented mitochondrial dysfunction.Conclusion: Our results demonstrate a role for 17ß-estradiol for the prevention of skeletal muscle mass loss in female tumor bearing mice. Furthermore, 17ß-estradiol prevented cachexia's disruption in skeletal muscle signaling involving AMPK and mTORC1, in addition to improving mitochondrial function in female tumor bearing mice.

Ovarian function's role during cancer cachexia progression in the female mouse.

Cachexia is a debilitating condition that occurs with chronic disease, including cancer; our research has shown that some regulation of cancer cachexia progression is affected by sex differences. The ApcMin/+ mouse is genetically predisposed to develop intestinal tumors; IL-6 signaling and hypogonadism are associated with cachexia severity in the male. This relationship in the female warrants further investigation, as we have shown that the ability of IL-6 to induce cachexia differs between the sexes. Since ovarian reproductive function relies on a complex system of endocrine signaling to affect whole body homeostasis, we examined the relationship between ovarian reproductive function and progression of cancer cachexia in the female ApcMin/+ mouse. Our study of ovarian reproductive function in female ApcMin/+ mice showed disease-related cessation of estrous cycling (acyclicity) in 38% of mice. Acyclicity, including morphological and functional losses and enhanced muscle inflammatory gene expression, was associated with severe cachexia. Interestingly, ovariectomy rescued body weight and muscle mass and function but increased muscle sensitivity to systemic IL-6 overexpression. In conclusion, our results provide evidence for a relationship between ovarian reproductive function and cachexia progression in female ApcMin/+ mice.

Abstract 2604: Chemoprevention of colorectal cancer by LFA-9, a novel dual mPGES-1/5-LOX inhibitor: safer approaches to chemoprevention

Abstract Colorectal cancer (CRC) protective effects of NSAIDs and COX-2 inhibitors are well established; however, they are associated with gastrointestinal (GI) bleeding and cardiovascular risk. Mechanistic studies suggest that sparing COX-1/2, prostaglandin (PG)I2 synthase and selectively targeting microsomal PG synthase-1 (mPGES-1) and 5-lipoxygenase (5-LOX) would inhibit PGE2 and Leukotrienes (LTs), respectively. To design and develop selective inhibitors of mPGES-1/5-LOX, we used insilico small molecular docking simulation approaches, and identified LFA-9 as a novel selective dual mPGES-1/5-LOX inhibitor among &amp;gt;20 analogs. Azoxymethane (AOM)-induced rat colonic tumors were utilized to assess inhibitory effects of LFA-9 on mPGES-1 and 5-LOX ex-vivo. At 7.5 μM, LFA-9 inhibited the mPGES-1 and 5-LOX activities by ∼57% and ∼68%, respectively. Maximum tolerable dose (100 -1,600ppm) of LFA-9 in AIN-76A diet on male C57Bl/6 mice were tested and observed that &amp;lt;1,600 ppm dietary LFA-9 to be safe and free from liver, GI and hematological toxicities. In AOM/DSS-induced colonic inflammation in rat, LFA-9 at ≥200ppm abolished the inflammation and suppressed mPGES-1 and 5-LOX activities in a dose-response manner. Potential CRC preventive efficacy of LFA-9 was assessed in AOM-rat carcinogenesis with colonic Aberrant Crypt Foci, (ACF) as surrogate marker in male F344 rats and intestinal tumor inhibition in APCMin/+ mice. In rats, colonic ACF were induced by AOM/DSS treatment and two week after the AOM/DSS treatment, LFA-9 (200, 400, and 600ppm) was fed by diet and ACF were evaluated after six-weeks. LFA-9 showed dose-response (P&amp;lt;0.0001) inhibitory effect on ACFs formation. At 600ppm, LFA-9 significantly inhibited colonic total ACF and multi-crypts by &amp;gt;60% (P&amp;lt;0.0001). In APCMin/+ mice study, six-week-old male and female mice (10/group) were fed diet containing 0, 350, and 700 ppm LFA-9 for 14 weeks. Male and female APCMin/+ mice fed control diet developed 58±3.8 (Mean±SEM) and 59±5.9 polyps, respectively. LFA-9 administration at 350 and 700ppm in APCMin/+ mice significantly (p&amp;lt;0.0001) reduced total intestinal tumor multiplicity and size dose-dependently (31.6± 5.9 and 24.3±3.7, male mice; and 26.2±5.6 and 15.5±1.8, female mice, respectively). At the high dose both male and female mice showed a &amp;gt; 80% suppression of polyps with &amp;gt;2mm size. Mice fed 350ppm LFA9 showed colon tumor inhibition of 60% (male) and 90% (female). It is noteworthy that both male and female mice fed 700ppm LFA-9 showed 91% inhibition of colon tumors. LFA-9 showed significant suppression of markers of proliferation and inflammation. Overall, above results suggest LFA-9 as a novel dual mPGES-1/5-LOX inhibitor, a safer agent than other NSAIDs and has a potential for prevention of CRC in high-risk patients. (Grant Support: NCI N01-CN 25001-26). Citation Format: Naveena B. Janakiram, Altaf Mohammed, Gopal Pathuri, Venkateshwar Madka, Rebekah Ritchie, Taylor Bryant, Yuting Zhang, Qian Li, Stan Lightfoot, Hariprasad Gali, Steele E. Vernon, Chen S. Suen, Chinthalapally V. Rao. Chemoprevention of colorectal cancer by LFA-9, a novel dual mPGES-1/5-LOX inhibitor: safer approaches to chemoprevention. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2604.

Cysteinyl leukotriene 1 receptor influences intestinal polyp incidence in a gender-specific manner in the ApcMin/+ mouse model.

There is emerging literature emphasizing the role of inflammatory eicosanoids, including prostaglandins and leukotrienes, in cancer development. Increased expression of both the cysteinyl leukotriene receptor 1 (CysLTR1) and the enzyme responsible for the production of leukotrienes, 5-lipoxygenase, is associated with poor prognosis in patients with colorectal adenocarcinomas. Apc mutation is an early event in the development of sporadic and hereditary (familial adenomatous polyposis) colorectal cancer. We utilized the Apc(Min/+) mouse model of familial adenomatous polyposis/sporadic colorectal cancer to investigate the role of CysLTR1 in intestinal tumorigenesis by crossing Apc(Min/+) mice with mice lacking the Cysltr1 gene. We could observe a reduced tumor burden in the small intestine of double-mutant female (Cysltr1 (-/-) Apc (Min/+) ) but not double-mutant male mice, compared with gender-matched single-mutant (Cysltr1 (+/+) Apc (Min/+) ) mice. This reduction was in a Cysltr1-dependent manner, female double-mutant mice having significantly reduced tumor formation compared with control littermates. The female double-mutant phenotype was accompanied with decreased systemic inflammation, as evidenced by significantly reduced serum levels of prostaglandin E2 and CysLTs, as well as increased CD3(+)CD8(+) T-cell tumor infiltration. Furthermore, the reduced formation of polyps in double-mutant (Cysltr1 (-/-) Apc (Min/+) ) female mice could in part be explained by the cytotoxic action of CD3(+)CD8(+) T cells in the polyp and reduced nuclear accumulation of β-catenin in the epithelium of small intestinal polyps. Our results stress the important role that CysLTR1 plays in colorectal cancer and its potential as a therapeutic target in cancer therapy.

Impairment of the non-homologous end joining and homologous recombination pathways of DNA double strand break repair: Impact on spontaneous and radiation-induced mammary and intestinal tumour risk in Apcmin/+ mice

Female Apcmin/+ mice carrying the BALB/c variant of Prkdc or heterozygous knockout for Xrcc2, were sham- or 2Gy X-irradiated as adults to compare the effect of mild impairments of double–strand break (DSB) repair pathways, non-homologous end joining (NHEJ) and homologous recombination (HR) respectively on spontaneous and radiation–induced mammary and intestinal tumorigenesis. Mice with impaired NHEJ showed no difference in incidence of spontaneous mammary tumours, compared with matched controls, (2.46 fold, P=0.121) and significantly less following irradiation (radiation–induced excess; 0.35 fold, P=0.008). In contrast mice with impaired HR presented with significantly less spontaneous mammary tumours than matched controls (0.33 fold, P=0.027) and significantly more following irradiation (radiation-induced excess; 3.3 fold, P=0.016). Spontaneous and radiation-induced intestinal adenoma multiplicity in the same groups were significantly greater than matched controls for mice with impaired NHEJ (sham; 1.29 fold, P<0.001, radiation–induced excess; 2.55 fold, P<0.001) and mice with impaired HR showed no significant differences (sham; 0.92 fold, P=0.166, radiation-induced excess; 1.16, P=0.274). Genetic insertion events were common in spontaneous tumours from NHEJ impaired mice compared with matched controls. γH2AX foci analysis suggests a significantly faster rate of DSB repair (MANOVA P<0.001) in intestinal than mammary tissue; apoptosis was also higher in irradiated intestine.To conclude, results suggest that pathway of choice for repair of spontaneous and radiation-induced DSBs is influenced by tissue type. NHEJ appears to play a greater role in DSB repair in intestinal tissue since impairment by functional change of Prkdc significantly increases the rate of mis-repair in intestinal but not mammary tissue. HR appears to play a greater role in DSB repair in adult mammary tissue since impaired HR results in significant changes in mammary but not in the intestinal tumorigenesis. This indicates that early DNA damage response and repair is important for cancer susceptibility and plays a role in determining tissue specificity of cancer risk.

Abstract 807: Parental radiation elicits increased intestinal tumorigenesis in the F1 generation of APCMin/+ and APC1638N/+ mice

Abstract The risk of colorectal cancer (CRC) has been reported to increase with radiation exposures as well as with a positive family history. Radiation exposure has also been implicated in inducing heritable changes in parental germline cells and thus increasing risk of cancer in the offspring. However, effects of parental radiation exposure on trans-generational colorectal carcinogenesis in offspring have not been explored yet. We employed two well-characterized mouse models (APCMin/+ and APC1638N/+) of human CRC to determine trans-generational effects of low dose radiation on colorectal carcinogenesis. Male APCMin/+ and APC1638N/+, and female C57BL/6J mice were exposed to whole body 25 cGy of x rays. Mating was initiated two days after radiation exposure, F1 offspring were genotyped, and male and female APCMin/+ and APC1638N/+ were grouped and housed separately. APCMin/+ mice were euthanized 150 days after birth, APC1638N/+ mice after 210 days, and tumor frequency and size in intestine and colon were noted. Significantly increased intestinal tumor frequency and increased numbers of larger tumors were observed in F1 mice of irradiated parents relative to F1 mice of sham-irradiated parents. Greater trans-generational tumorigenic effects of radiation were observed in male offspring relative to female offspring. In conclusion, here we present an early report for the first time that low dose radiation exposure has a trans-generational effect on intestinal tumorigenesis with potential implications for radiation exposure-related human health consequences. Citation Format: Shubhankar Suman, Santosh Kumar, Bo-Hyun Moon, Ziling Fan, Albert J. Fornace, Kamal Datta. Parental radiation elicits increased intestinal tumorigenesis in the F1 generation of APCMin/+ and APC1638N/+ mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 807. doi:10.1158/1538-7445.AM2015-807

Krüppel-like factor 9 (KLF9) prevents colorectal cancer through inhibition of interferon-related signaling.

Expression of the transcription factor Krüppel-like factor 9 (KLF9) is frequently reduced in colorectal cancers, although a tumor suppressive role has not been established. To determine if KLF9 suppresses intestinal adenoma formation, we generated mice of distinct Klf9 genotypes in the background of the Apc (Min/+) mouse and compared their adenoma burdens at 16 weeks of age. While small intestine adenoma burden remained unchanged among Klf9 genotypes, male and female Apc(Min/+)/Klf9(-/-) and Apc(Min/+)/Klf9(+/-) mice exhibited significantly more colon adenomas than their Apc(Min/+)/Klf9(+/+) counterparts. Microarray analysis showed significant increases in the expression of interferon-induced genes in the colon mucosa of female Apc (Min/+)/Klf9(+/-) and Apc(Min/+)/Klf9(-/-) compared to Apc(Min/+)/Klf9(+/+) mice, prior to overt adenoma occurrence. Gene upregulation was confirmed by qPCR of colon mucosa and by siRNA knockdown of KLF9 in human HT29 colorectal cancer cells. Increases in expression of these genes were further augmented by supplementation with Interferon β1. Circulating levels of the cytokine, interferon-stimulated gene 15 (ISG15) were increased in Apc(Min/+)/Klf9(+/-) and Apc(Min/+)/Klf9(-/-) mice relative to Apc(Min/+)/Klf9(+/+). Additionally, colon mucosal levels of ISG15 were increased in Apc(Min/+)/Klf9(+/-) mice. Chromatin immunoprecipitation demonstrated KLF9 recruitment to the ISG15 promoter. Lastly, treatment with ISG15 suppressed apoptosis in HT29 cells, in the presence and absence of 5-fluorouracil (5FU). Results show KLF9 to be a haploinsufficient suppressor of colon tumorigenesis in Apc(Min/+) mice in part, by repression of ISG15 and the latter's antiapoptotic function. Krüppel-like factor 9 (KLF9) is a haploinsufficient tumor suppressor in the ApcMin/+ mouse colon by suppressing expression of ISG15, an apoptosis-inhibiting cytokine.

IL‐6 Signaling during Cancer Cachexia Progression: The Female Response

Cachexia arises secondary to many chronic diseases and accounts for about 30% of cancer‐related deaths. Cachexia occurs in both sexes, but its etiology and progression have been almost exclusively examined in the male. Interleukin‐6 (IL‐6) has become an attractive therapeutic target as IL‐6 signaling is a recognized regulator of male ApcMin/+ mouse cancer cachexia progression. Despite established sex‐dependent inflammatory responses, how IL‐6 signaling contributes to female cancer cachexia progression is unknown. Consequently, we examined the role of circulating IL‐6 for female ApcMin/+ mouse cancer cachexia progression. Female ApcMin/+ mice weight and functional testing were monitored until sacrifice at 18 weeks of age. A second group of female ApcMin/+ mice underwent IL‐6 overexpression at 15 weeks of age. Blood and hindlimb muscle were collected to examine IL‐6 levels and downstream signaling. Mice were stratified into weight stable, initially cachectic, and severely cachectic groups. Plasma IL‐6 did not differ between groups (17.6 ± 6.7; 34.4 ± 18.9; 39.3 ± 13.1 pg/ml); however, muscle IL‐6 mRNA correlated with body weight loss and hindlimb muscle mass (p=0.008, 0.019). Muscle IL‐6r, gp130, and SOCS3 mRNA expression did not change with cachexia severity. Muscle STAT3 phosphorylation increased with severe cachexia compared to initial cachexia (14.8 ± 1.6 vs 5.2 ± 2.1 fold change relative to WT levels). Surprisingly, IL‐6 over‐expression did not increase muscle IL‐6 signaling or bodyweight loss. Overall, elevated IL‐6 does not exacerbate cachexia progression in the female ApcMin/+ mouse.

Effects of Quercetin on Muscle Function during IL‐6‐induced Cancer Cachexia

Cachexia is a devastating wasting condition that occurs secondary to chronic diseases including AIDS, COPD, and cancer. Characterized by a loss of body weight including adipose tissue and muscle atrophy, 20-50% of cancer patients are affected with an annual mortality rate of 80%. It is known that IL-6 drives cachexia in the male ApcMin/+ mouse. Quercetin, an anti-inflammatory flavonoid, has been shown to attenuate symptoms of cachexia. There is evidence that this occurs through the IL-6 pathway; however, this has not been directly tested. The purpose of this study was to determine whether quercetin could attenuate muscle function loss caused by systemic IL-6 over-expression in female ApcMin/+mice. Our hypothesis was that IL-6 over-expression would exacerbate muscle strength and endurance decrements, which would be attenuated by quercetin supplementation in cachectic female ApcMin/+ mice. Female ApcMin/+ mice (n=24) were divided into 4 groups at 15 weeks of age: 1) Control 2) IL-6 electroporation (50 μg plasmid in 50 μl PBS), 3) daily quercetin gavage (75 mg/kg body weight), 4) IL-6 electroporation + quercetin. Functional testing including voluntary grip strength, run to fatigue, and DEXA scan were performed before treatment and at time of sacrifice. Quercetin attenuated grip strength loss compared to control mice (p=0.02); however, this effect was abolished by the overexpression of IL-6 in addition to quercetin. Quercetin was unable to rescue muscle endurance loss. Further analysis will determine the pathways by which quercetin and IL-6 exert their effects on muscular strength and endurance in cachectic female ApcMin/+mice.

Improved innate immune responses by Frondanol A5, a sea cucumber extract, prevent intestinal tumorigenesis.

Sea cucumbers are a source of antibacterial, anti-inflammatory, and anticancer compounds. We show that sea cucumber extract Frondanol A5 is capable of enhancing innate immune responses and inhibiting intestinal tumors in APC(Min/+) mice. APC(Min/+) mice were fed semi-purified diets containing 0, 250, or 500 ppm FrondanolA5 for 14 weeks before we assessed intestinal tumor inhibition. Dietary Frondanol A5 suppressed small intestinal polyp sizes and formation up to 30% (P < 0.02) in males and up to 50% (P < 0.01) in females. Importantly, 250 and 500 ppm Frondanol A5 diet suppressed colon tumor multiplicities by 65% (P < 0.007) and 75% (P < 0.0001), compared with untreated male APC(Min/+) mice. In female APC(Min/+) mice, both dose levels of Frondanol A5 suppressed colon tumor multiplicities up to 80% (P < 0.0001). Isolated peritoneal macrophages from treated mice showed increased phagocytosis efficiency (control 24% vs. treated 50%; P < 0.01) and an increase in GILT mRNA expression, indicating increased innate immune responses by these cells in treated animals. Similarly, we observed an increase in GILT expression in treated tumors, compared with untreated tumors. Furthermore, an increase in G-CSF cytokine, a decrease in inflammatory cytokines and marker 5-LOX, its regulator FLAP, proliferation (PCNA), and angiogenesis (VEGF) markers were observed in treatment groups. These data suggest that Frondanol A5 decreased inflammatory angiogenic molecules and increased GILT expression and macrophage phagocytosis. These decreases may have improved the innate immune systems of the treated mice, thus aiding in inhibition of intestinal tumor formation. These results suggest that Frondanol A5 exhibits significant chemopreventive potential against intestinal tumorigenesis.

Sex differences in the relationship of IL-6 signaling to cancer cachexia progression

A devastating aspect of cancer cachexia is severe loss of muscle and fat mass. Though cachexia occurs in both sexes, it is not well-defined in the female. The ApcMin/+ mouse is genetically predisposed to develop intestinal tumors; circulating IL-6 is a critical regulator of cancer cachexia in the male ApcMin/+ mouse. The purpose of this study was to examine the relationship between IL-6 signaling and cachexia progression in the female ApcMin/+ mouse. Male and female ApcMin/+ mice were examined during the initiation and progression of cachexia. Another group of females had IL-6 overexpressed between 12 and 14weeks or 15–18weeks of age to determine whether IL-6 could induce cachexia. Cachectic female ApcMin/+ mice lost body weight, muscle mass, and fat mass; increased muscle IL-6 mRNA expression was associated with these changes, but circulating IL-6 levels were not. Circulating IL-6 levels did not correlate with downstream signaling in muscle in the female. Muscle IL-6r mRNA expression and SOCS3 mRNA expression as well as muscle IL-6r protein and STAT3 phosphorylation increased with severe cachexia in both sexes. Muscle SOCS3 protein increased in cachectic females but decreased in cachectic males. IL-6 overexpression did not affect cachexia progression in female ApcMin/+ mice. Our results indicate that female ApcMin/+ mice undergo cachexia progression that is at least initially IL-6-independent. Future studies in the female will need to determine mechanisms underlying regulation of IL-6 response and cachexia induction.

Abstract 2145: Chemopreventive and immune-modulatory effects of the Cucumaria frondosa extract, Frondanol A5 in the APCMin/+ mice intestinal tumorigenesis

Abstract Sea cucumbers have been used widely as a food source and for their health benefits, which include treatment of various chronic inflammatory conditions. We have shown previously that Cucumaria frondosa extract, Frondanol A5 inhibits azoxymethane -induced colonic precursor lesions in F344 rats. Experiments were designed to assess the chemopreventive efficacy of Frondanol A5, for suppression of intestinal tumorigenesis in male and female APCMin/+ mice. Six-week-old APCMin/+ mice were fed the modified AIN-76A diets containing 0, 250 or 500 ppm Frondanol A5 for 14 weeks. To understand molecular mechanisms, we analyzed levels of proliferation, inflammatory and angiogenesis makers; PCNA, inflammatory cytokines, 5-lipoxygenase (5-LOX), Five Lox Activating Protein (FLAP) and vascular endothelial growth factor (VEGF) expressions by IHC, IHF, and/or RT-PCR methods. To determine immuno-modulatory effects of Fondanol A5 on intestinal tumorigenesis, number of macrophages was evaluated in the blood, SI polyps and colon tumors by Giemsa staining, ex-vivo phagocytic assay was performed on the peritoneal macrophages isolated from the control and treated mice. Further, γ-interferon-inducible lysosomal thiolreductase (GILT) mRNA expression was analyzed in the peritoneal macrophages, SI polyps and colonic tumors. Dietary administration of 250 and 500 ppm of Frondanol A5 suppressed small intestinal polyp formation up to 28 % (p&amp;lt;0.02) in males and up to 50 % (p&amp;lt;0.01) in females; and significantly decreased polyp size in both genders. Importantly, 250 and 500 ppm Frondanol A5 diet suppressed colon tumors multiplicities by 65% (p&amp;lt;0.007) and 75% (p&amp;lt;0.0001) as compared to control diet fed male APCMin/+ mice. Similarly, in female APCMin/+ mice, dietary Frondanol A5 at both dose levels suppressed colon tumor multiplicities up to 80% (p&amp;lt;0.0001). Frondanol A5 showed significant colon tumor inhibitory dose-response effects in male APCMin/+ mice. Intestinal tumors of Frondanol A5-fed mice showed significantly reduced expression of PCNA, 5-LOX, its regulator molecule, FLAP and angiogenic marker VEGF. Frondanol A5-fed-mice showed suppression of serum inflammatory cytokines and increased expression of granulocyte-colony stimulating factor (G-CSF) by ELISA. Importantly, mice treated with Frondanol A5 diet showed enhanced phagocytic activity and increase in number of macrophages (Control 24% Vs treated 50%; p&amp;lt;0.01) and caused a significant increase in GILT mRNA expression, in both peritoneal macrophages as well as colonic tumors. These results suggest that Frondanol A5 exhibits significant chemopreventive potential in FAP model of SI and colon tumorigenesis. Frondanol A5 induced antitumor activities in part mediated through modulation of inflammatory molecules and stimulation of macrophage activity. Supported by NIH Grant N01-CN-53300 and R01CA094962. Citation Format: Naveena B. Janakiram, Altaf Mohammed, Misty Brewer, Peter D. Collin, Vernon E. Steele, Chinthalapally V. Rao. Chemopreventive and immune-modulatory effects of the Cucumaria frondosa extract, Frondanol A5 in the APCMin/+ mice intestinal tumorigenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2145. doi:10.1158/1538-7445.AM2014-2145

The effect of sex on IL‐6 regulation of cancer cachexia progression in the Apc min/+ mouse (704.2)

Cachexia is a condition that arises secondary to many chronic diseases and accounts for more than 20% of cancer‐related deaths. Cachexia occurs in both sexes, but research into its etiology and progression has been almost exclusively in the male. Our lab has previously shown that body weight loss in the male Apc min/+ mouse is closely associated with plasma IL‐6 and triglyceride levels as well as tumor burden. The purpose of the present study was to determine if sex alters IL‐6 regulation of cachexia progression in Apc min/+ mice. 24 female Apc min/+ mice were monitored during the development of cachexia until sacrifice at 20 weeks of age. Plasma IL‐6 and triglycerides as well as intestinal polyps were quantified. Body weight loss from peak ranged from 0% to 21%, with 30% of mice becoming severely cachectic. Plasma IL‐6 levels varied from 4.4‐39.7 pg/ml, which is comparable to the male. Similar to the male, body weight loss was correlated with tumor number (p=0.01). Unlike the male, there was neither a relationship between body weight loss and plasma IL‐6 or triglyceride levels; nor between tumor number and plasma IL‐6 level. Interestingly, muscle mass loss was inversely correlated with plasma IL‐6 level (p=0.03), which is contrary to the male. We present evidence that sex can affect the relationship between muscle mass loss, cachexia development, and plasma IL‐6 in the Apc min/+ mouse, which may impact therapeutics for cachexia.

Raloxifene and Antiestrogenic Gonadorelin Inhibits Intestinal Tumorigenesis by Modulating Immune Cells and Decreasing Stem-like Cells

Studies suggest that estrogen plays a contributing role in colorectal cancer. This project examined the preventive effects of raloxifene, a selective estrogen receptor modulator (SERM), and gonadorelin, an antiestrogenic drug, in female Apc(Min/+) mouse intestinal tumorigenesis. Six-week-old Apc(Min/+)mice were fed diet containing 1 ppm raloxifene or control diet. Gonadorelin (150 ng/mouse) was injected subcutaneously into one treatment group. Intestinal tumors were evaluated for tumor multiplicity and size. Mice treated with raloxifene and gonadorelin showed colon tumor inhibition of 80% and 75%, respectively. Both drugs significantly inhibited small intestinal tumor multiplicity and size (75%-65%, P < 0.0001). Raloxifene and gonadorelin showed significant tumor inhibition with 98% and 94% inhibition of polyps >2 mm in size. In mice fed with raloxifene or injected with gonadorelin, tumors showed significantly reduced proliferating cell nuclear antigen expression (58%-65%, P < 0.0001). Raloxifene treatment decreased β-catenin, cyclin D1, laminin 1β, Ccl6, and stem-like cells (Lgr 5, EpCAM, CD44/CD24), as well as suppressed inflammatory genes (COX-2, mPGES-1, 5-LOX,). Gonadorelin showed significant decrease in COX-2, mPGES-1, iNOS, and stem-like cells or increased NK cells and chemokines required for NK cells. Both drugs were effective in suppressing tumor growth albeit with different mechanisms. These observations show that either suppression of estrogen levels or modulation of estrogen receptor dramatically suppresses small intestinal and colonic tumor formation in female Apc(Min/+) mice. These results support the concept of chemoprevention by these agents in reducing endogenous levels of estrogen or modulating ER signaling.