Colorectal Cancer Murine Model Research Articles

Targeting tumor-infiltrating CCR8+ regulatory T cells induces antitumor immunity through functional restoration of CD4+ Tconvs and CD8+ T cells in colorectal cancer

BackgroundChemokine (C-C motif) receptor 8 (CCR8) is a chemokine receptor selectively expressed on tumor-infiltrating regulatory T cells (Tregs). Strong immunosuppression mediated by CCR8+ Tregs observed in breast and lung malignancies suggest for their functional significance in cancer therapy. To date, detailed characterization of tumor-infiltrating CCR8+ Tregs cells in colorectal cancer (CRC) is limited.MethodsTo study the presence and functional involvement of CCR8+ Tregs in CRC, we analyzed the proportions of CCR8-expressing T cells in different T cell subsets in tumor and adjacent normal tissues and peripheral blood mononuclear cells (PBMCs) from CRC patients by Flow cytometry. Also, we compared the distribution of CCR8+ T cells in malignant tissues and peripheral lymphoid organs from a subcutaneous CRC murine model. Bioinformatic analysis was performed to address the significance of CCR8 expression levels in CRC prognosis, immune regulatory gene expression profiles and potential molecular mechanisms associated with CCR8+ Tregs in CRC tumors. Further, we administrated an anti-CCR8 monoclonal antibody to CT26 tumor-bearing mice and examined the antitumor activity of CCR8-targeted therapy both in vivo and in an ex vivo confirmative model.ResultsHere, we showed that Tregs was predominantly presented in the tumors of CRC patients (13.4 ± 5.8, p < 0.0001) and the CRC subcutaneous murine model (35.0 ± 2.6, p < 0.0001). CCR8 was found to be preferentially expressed on these tumor-infiltrating Tregs (CRC patients: 63.6 ± 16.0, p < 0.0001; CRC murine model: 65.3 ± 9.5, p < 0.0001), which correlated with poor survival. We found that majority of the CCR8+ Tregs expressed activation markers and exhibited strong suppressive functions. Treatment with anti-CCR8 antibody hampered the growth of subcutaneous CRC tumor through effectively restoring the anti-tumor immunity of CD4+ conventional T cells (CD4+ Tconvs) and CD8+ T cells, which was confirmed in the ex vivo examinations.ConclusionsCollectively, these findings illustrate the importance of CCR8+ Tregs for an immunosuppressive microenvironment in CRC tumors by functional inhibition of CD4+ Tconvs and CD8+ T cells, and suggest for the applicable value of CCR8-targeted therapy for CRC.

Laherradurin Inhibits Tumor Growth in an Azoxymethane/Dextran Sulfate Sodium Colorectal Cancer Model In Vivo.

Colorectal cancer (CRC) is the third most common neoplasia in the world. Its mortality rate is high due to the lack of specific and effective treatments, metastasis, and resistance to chemotherapy, among other factors. The natural products in cancer are a primary source of bioactive molecules. In this research, we evaluated the antitumor activity of an acetogenin (ACG), laherradurin (LH), isolated from the Mexican medicinal plant Annona macroprophyllata Donn.Sm. in a CRC murine model. The CRC was induced by azoxymethane-dextran sulfate sodium (AOM/DSS) in Balb/c mice and treated for 21 days with LH or cisplatin. This study shows for the first time the antitumor activity of LH in an AOM/DSS CRC model. The acetogenin diminished the number and size of tumors compared with cisplatin; the histologic studies revealed a recovery of the colon tissue, and the blood toxicity data pointed to less damage in animals treated with LH. The TUNEL assay indicated cell death by apoptosis, and the in vitro studies exhibited that LH inhibited cell migration in HCT116 cells. Our study provides strong evidence of a possible anticancer agent for CRC.

Antitumor effect of tubeimoside-I on murine colorectal cancers through PKM2-dependent pyroptosis and immunomodulation.

Induction of cancer cell death is an established treatment strategy, but chemotherapy drug-mediated apoptosis can be evaded by many tumors. Pyroptosis is a type of inflammatory programmed cell death (PCD) that is important for organism immunity. Tubeimoside-I (TBMS1) is a plant-derived component that exhibits antitumor activity. However, it is unclear how TBMS1 induces pyroptosis to inhibit colorectal cancer (CRC). In this study, we demonstrated that TBMS1 is able to induce pyroptosis in murine CRC cells and releases pro-inflammatory cytokines. Mechanistically, we found that TBMS1 inhibits CRC cell proliferation and migration and induces pyroptosis by activating caspase-3 and cleaving gasdermin E (GSDME) through the inhibition of PKM2. In the animal experiments, TBMS1 attenuated the weight of solid tumors, increased the proportion of CD8+ cytotoxic T cells, and reduced the content of M2-type macrophages in the spleen of tumor-bearing mice. Furthermore, TBMS1 inhibited M2-type polarization by blocking STAT6 pathway activation in RAW 264.7 cells. To sum up, our findings suggest that TBMS1 triggers pyroptosis in CRC by acting on the PKM2/caspase-3/GSDME signaling pathway. Additionally, it modulates the antitumor immune response in CRC murine models. This study provides a promising basis for the potential use of TBMS1 in treating CRC.

Global proteomic identifies multiple cancer-related signaling pathways altered by a gut pathobiont associated with colorectal cancer

In this work, we investigated the oncogenic role of Streptococcus gallolyticus subsp. gallolyticus (SGG), a gut bacterium associated with colorectal cancer (CRC). We showed that SGG UCN34 accelerates colon tumor development in a chemically induced CRC murine model. Full proteome and phosphoproteome analysis of murine colons chronically colonized by SGG UCN34 revealed that 164 proteins and 725 phosphorylation sites were differentially regulated. Ingenuity Pathway Analysis (IPA) indicates a pro-tumoral shift specifically induced by SGG UCN34, as ~ 90% of proteins and phosphoproteins identified were associated with digestive cancer. Comprehensive analysis of the altered phosphoproteins using ROMA software revealed up-regulation of several cancer hallmark pathways such as MAPK, mTOR and integrin/ILK/actin, affecting epithelial and stromal colonic cells. Importantly, an independent analysis of protein arrays of human colon tumors colonized with SGG showed up-regulation of PI3K/Akt/mTOR and MAPK pathways, providing clinical relevance to our findings. To test SGG’s capacity to induce pre-cancerous transformation of the murine colonic epithelium, we grew ex vivo organoids which revealed unusual structures with compact morphology. Taken together, our results demonstrate the oncogenic role of SGG UCN34 in a murine model of CRC associated with activation of multiple cancer-related signaling pathways.

Targeting Ubiquitin-like Protein, ISG15, as a Novel Tumor Associated Antigen in Colorectal Cancer.

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in both men and women in the United States. While immune checkpoint inhibitor (ICI) therapy is demonstrating remarkable clinical responses, the resistance and immune-related toxicities associated with ICIs demonstrate the need to develop additional immunotherapy options for CRC patients. Cancer vaccines represent a safe and promising treatment approach for CRC. As previously developed tumor-associated antigen (TAA)-based cancer vaccines for CRC are not demonstrating promising results, we propose that interferon-stimulated gene 15 (ISG15) is a novel TAA and therapeutic target for CRC. Our work demonstrates the anti-tumor efficacy of a Listeria-based vaccine targeting ISG15, designated Lm-LLO-ISG15, in an immunocompetent CRC murine model. The Lm-LLO-ISG15-mediated anti-tumor response is associated with an increased influx of functional T cells, higher production of multiple intracellular cytokines response, a lower number of regulatory T cells, and a greater ratio of effector to regulatory T cells (Teff/Treg) in the tumor microenvironment.

MAP7D2 reduces CD8+ cytotoxic T lymphocyte infiltration through MYH9-HMGB1 axis in colorectal cancer

Immune checkpoint inhibitors (ICIs) represent a new paradigm in cancer immunotherapy, but can be largely restricted by the limited presence of CD8+ cytotoxic T lymphocytes (CTLs) in colorectal cancer (CRC) patients with microsatellite stable (MSS) tumors. Here, through next-generation sequencing, we identify microtubule-associated protein 7 domain 2 (MAP7D2) as an exploitable therapeutic maneuver to improve the efficacy of ICIs for MSS CRC therapy. In human CRC tissues, MAP7D2 expression is significantly increased in MSS CRC, and MAP7D2 adversely correlates with the presence of antitumor T lymphocytes. Invitro and in vivo experiments demonstrate that MAP7D2 knockdown significantly increases the infiltration of CD8+ CTLs, thereby inhibiting tumor progression and improving the efficacy of ICIs in MSS CRC murine models. Mechanistically, MAP7D2 interacts with MYH9 and protects it from ubiquitin-mediated degradation, subsequently decreasing the secretion of HMGB1, which suppresses the infiltration of CD8+ CTLs in MSS CRC. These findings highlight the importance of MAP7D2 in determining the infiltration of CD8+ CTLs and indicate that targeting MAP7D2 in MSS CRC may present a novel antitumor immunotherapy.

Colorectal cancer inhibition by BET inhibitor JQ1 is MYC-independent and not improved by nanoencapsulation

Bromodomain and extraterminal domain protein inhibitors (BETi) for cancer treatment did not convince during their first clinical trials. Their epigenetic mechanism of action is still not well understood, even if MYC is generally considered as its main downstream target. In this context, we intended to assess two new nanoformulations of the BETi JQ1 for the treatment of colorectal cancer (CRC). JQ1 was encapsulated at 10 mg/mL in lipid nanocapsules (LNC) or polymeric micelles (PM), both compatible for an intravenous administration. Their effect was compared with free JQ1 on several CRC cell lines in vitro and with daily intraperitoneal cyclodextrin (CD)-loaded JQ1 on the CT26 CRC tumor model in vivo. We showed that LNC preferentially accumulated in tumor, liver, and lymph nodes. LNC-JQ1 and CD-JQ1 similarly delayed tumor growth and increased median survival from 15 to 23 or 20.5 days. JQ1 altered MYC in only two among four CRC cell lines. This MYC-independence found in CT26 was confirmed in vivo by PCR and immunohistochemistry. The main explanation of the JQ1 anticancer effect was an increase in apoptosis. The investigation of its impact on the tumor microenvironment did not show significant effects. Finally, JQ1 association with irinotecan did not synergize in vivo with JQ1 nanoformulations. In conclusion, we demonstrated that the JQ1 anticancer effect was not improved by nanoencapsulation even if their tumor delivery was probably higher. MYC inhibition was not associated to JQ1 efficacy in the case of the CT26 CRC murine model.

Blocking IL-17A enhances tumor response to anti-PD-1 immunotherapy in microsatellite stable colorectal cancer

BackgroundImmune checkpoint inhibitors (ICIs), including anti-PD-1 therapy, have limited efficacy in patients with microsatellite stable (MSS) colorectal cancer (CRC). Interleukin 17A (IL-17A) activity leads to a protumor microenvironment, dependent on...

Abstract 4296: The EphA2/EGFR pathway dysregulation associates with poor prognosis and cetuximab treatment response in colorectal cancer

Abstract Tumor heterogeneity and the presence of stem-like cells have been identified as key features for resistance to anticancer treatments including targeted therapy. The Eph receptors comprise a large family of receptor tyrosine kinases that marks stem-like cells in different tissues. In colorectal cancer (CRC), EphA2 receptor overexpression has been linked to stem-like properties of cells and malignancy. In particular, EphA2 is involved in multiple cross-talks with other cellular networks including EGFR, FAK and VEGF pathways, with which it collaborates to stimulate cell migration, invasion and metastasis. We investigated the molecular crosstalk and miRNAs modulation of the EphA2 and EGFR pathways in CRC. We also explored the role of EphA2/EGFR pathway mediators as prognostic factors or predictors of cetuximab benefit in CRC patients. We used a strategy to uncover in murine homogeneous tumor EphA2high cells a novel potential molecular signature involving EphA2 and EGFR pathways. Gene expression analysis was performed in EphA2high cells isolated from colorectal adenocarcinoma obtained from the AOM/DSS-induced CRC murine model. Six independent cohorts of patients were analyzed to determine the potential prognostic role of a EphA2/EGFR signature and its effect on cetuximab treatment response. We identified a gene expression pattern, including a coherent miRNAs dysregulation, reflecting the activation of EphA2 and EGFR pathways. Such pattern showed prognostic significance in stage I-III CRC patients, in both univariate and multivariate analysis. In patients with stage IV and WT KRAS, EphA2/Efna1/EGFR gene expression status was significantly associated with poor response to cetuximab. Furthermore, EphA2 and EGFR overexpression showed a combined effect relative to cetuximab resistance, independently from KRAS mutation status. Collectively, our data indicate that EphA2/Efna1/EGFR genes, linked to a possible control by miRNAs, could be proposed as novel prognostic biomarkers in CRC. Moreover, EphA2 could be linked to a mechanism of resistance to cetuximab alternative to KRAS mutations. Since cetuximab resistance, associated to an intrinsic genetic heterogeneity, remains the most critical issue in treating CRC, this study sheds light on new potential biomarkers and therapeutically actionable kinase targets in the EphA2/EGFR-linked pathway. Citation Format: Mariangela De Robertis, Luisa Loiacono, Caterina Fusilli, Maria Luana Poeta, Tommaso Mazza, Massimo Sanchez, Luigi Marchionni, Emanuela Signori, Giuseppe Lamorte, Angelo Luigi Vescovi, Jesus Garcia-Foncillas, Vito Michele Fazio. The EphA2/EGFR pathway dysregulation associates with poor prognosis and cetuximab treatment response in colorectal 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 4296.

Alterations in the Gut Microbiome and Suppression of Histone Deacetylases by Resveratrol Are Associated with Attenuation of Colonic Inflammation and Protection Against Colorectal Cancer.

Inflammatory bowel disease (IBD) is known to significantly increase the risk for development of colorectal cancer (CRC), suggesting inflammation and cancer development are closely intertwined. Thus, agents that suppress inflammation may prevent the onset of cancer. In the current study, we used resveratrol, an anti-inflammatory stilbenoid, to study the role of microbiota in preventing inflammation-driven CRC. Resveratrol treatment in the azoxymethane (AOM) and dextran sodium sulphate (DSS) CRC murine model caused an increase in anti-inflammatory CD4 + FOXP3 + (Tregs) and CD4 + IL10 + cells, a decrease in proinflammatory Th1 and Th17 cells, and attenuated CRC development. Gut microbial profile studies demonstrated that resveratrol altered the gut microbiome and short chain fatty acid (SCFA), with modest increases in n-butyric acid and a potential butyrate precursor isobutyric acid. Fecal transfer from resveratrol-treated CRC mice and butyrate supplementation resulted in attenuation of disease and suppression of the inflammatory T cell response. Data also revealed both resveratrol and sodium butyrate (BUT) were capable of inhibiting histone deacetylases (HDACs), correlating with Treg induction. Analysis of The Cancer Genome Atlas (TCGA) datasets revealed increased expression of Treg-specific transcription factor FoxP3 or anti-inflammatory IL-10 resulted in an increase in 5-year survival of patients with CRC. These data suggest that alterations in the gut microbiome lead to an anti-inflammatory T cell response, leading to attenuation of inflammation-driven CRC.

Novel Lysine-Based Thioureas as Mechanism-Based Inhibitors of Sirtuin 2 (SIRT2) with Anticancer Activity in a Colorectal Cancer Murine Model.

Sirtuin 2 (SIRT2) is a protein lysine deacylase that has been indicated as a therapeutic target for cancer. To further establish the role of SIRT2 in cancers, it is necessary to develop selective and potent inhibitors. Here, we report the facile synthesis of novel lysine-derived thioureas as mechanism-based SIRT2 inhibitors with anticancer activity. Compounds AF8, AF10, and AF12 selectively inhibited SIRT2 with IC50 values of 0.06, 0.15, and 0.08 μM, respectively. Compounds AF8 and AF10 demonstrated broad cytotoxicity amongst cancer cell lines, but minimal toxicity in noncancerous cells. AF8 and AF10 inhibited the anchorage-independent growth of human colorectal cancer cell line HCT116 with GI50 values of ∼7 μM. Furthermore, AF8 potently inhibited tumor growth in a HCT116 xenograft murine model, supporting that SIRT2 is a viable therapeutic target for colorectal cancer.

32 Impact of colibactin-producing escherichia coli on immune microenvironment in preclinical colorectal cancer models

IntroductionIncreasing evidence link the immune microenvironment, microbiota and colorectal cancer (CRC). E. coli pks+ are more frequently detected on CRC patient mucosa and exhibit procarcinogenic properties in CRC murine models. Aim of this work was to evaluate the impact of chronical infection by colibactin-producing E. coli on immune cells in APCmin/+ mice colon.Material and methodsMin mice were per os inoculated with a CRC E. coli pks+ strain (11 G5), non-pathogenic E. coli (K-12) or PBS. Induction of oxidative stress and inflammation during the infection was evaluated using optical in vivo imaging (IVIS spectrum). After 7 weeks, number and volume of polyps were evaluated and colonic samples were histologically analysed. Immunofluorescent staining of immune cells (neutrophils and T cell populations) was performed to quantify positive cells in three interesting colon areas: mucosa, lymphoid follicle and tumour using an innovative algorithm created with Tissue Studio software. In parallel, quantification of immune cells (lymphoid populations) was performed in mesenteric lymph node (MLNs) by flow cytometry.Results and discussionsUsing optical imaging, we detected a significant increase of oxidative stress and inflammation in the gut after thirty days of 11 G5 infection. However, using our specific algorithm and CD45 immunostaining, we observed a significant increase of lymphoid follicle size in the gut of mice infected with the 11 G5 strains. Interestingly, follicle size was positively correlated with tumour volume suggesting an association between pro-carcinogenic properties of 11 G5 strain and gut immune response. In addition, we observed an increase of neutrophils on the mucosa and lymphoid follicle of 11 G5 infected mice. These results can be linked to our in vivo optical imaging observations. Moreover we observed a trend to decrease of CD3+ T cells on mucosa and tumour for the 11 G5 group, suggesting a possible link between E. coli pks +and anti-tumour T cells. Finally we noticed a significant decrease of CD4+ CD25+ anti-inflammatory T cells in MLNs of 11 G5 infected mice, negatively correlated with gut bacteria colonisation.ConclusionHere we report a potential immunomodulatory effect on gut microenvironment by pks+E. coli, which could be associated with its carcinogenic effect. Our results suggest that gut lymphoid follicle and immune cells such as neutrophils and T cells could be involved in this process. This work shows a link between immune microenvironment, pathogenic E. coli and tumour development.

SCF/C-Kit/JNK/AP-1 Signaling Pathway Promotes Claudin-3 Expression in Colonic Epithelium and Colorectal Carcinoma.

Claudin-3 is a major protein of tight junctions (TJs) in the intestinal epithelium and is critical for maintaining cell-cell adhesion, barrier function, and epithelium polarity. Recent studies have shown high claudin-3 levels in several solid tumors, but the regulation mechanism of claudin-3 expression remains poorly understood. In the present study, colorectal cancer (CRC) tissues, HT-29 and DLD-1 CRC cell lines, CRC murine model (C57BL/6 mice) and c-kit loss-of-function mutant mice were used. We demonstrated that elevated claudin-3 levels were positively correlated with highly expressed c-kit in CRC tissues based upon analysis of protein expression. In vitro, claudin-3 expression was clearly increased in CRC cells by overexpressed c-kit or stimulated by exogenous recombinant human stem cell factor (rhSCF), while significantly decreased by the treatment with c-kit or c-Jun N-terminal kinase (JNK) inhibitors. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay showed that SCF/c-kit signaling significantly promoted activator protein-1 (AP-1) binding with CLDN-3 promoter and enhanced its transcription activity. Furthermore, decreased expression of claudin-3 was obtained in the colonic epithelium from the c-Kit loss-of-function mutant mice. In conclusion, SCF/c-kit-JNK/AP-1 signaling pathway significantly promoted claudin-3 expression in colonic epithelium and CRC, which could contribute to epithelial barrier function maintenance and to CRC development.

A minimum core outcome dataset for the reporting of preclinical chemotherapeutic drug studies: Lessons learned from multiple discordant methodologies in the setting of colorectal cancer.

In vivo studies in animal models are critical tools necessary to study the fundamental complexity of carcinogenesis. A constant strive to improve animal models in cancer exists, especially those investigating the use of chemotherapeutic effectiveness. In the present systematic review, colorectal cancer (CRC) is used as an example to highlight and critically evaluate the range of reporting strategies used when investigating chemotherapeutic agents in the preclinical setting. A systematic review examining the methodology and reporting of preclinical chemotherapeutic drug studies using CRC murine models was conducted. A total of 45 studies were included in this systematic review. The literature was found to be highly heterogeneous with various cell lines, animal strains, animal ages and chemotherapeutic compounds/regimens tested, proving difficult to compare outcomes between similar studies or indeed gain any significant insight into which chemotherapeutic regimen caused adverse events. From this analysis we propose a minimum core outcome dataset that could be regarded as a standardised way of reporting results from in vivo experimentation.

Abstract 3300: Gal-GalNAc overexpressed in colorectal carcinoma mediates attachment and colonization of Fusobacterium nucleatum utilizing the Fap2 lectin

Abstract Recent reports revealed overabundance of oral Fusobacterium nucleatum (Fn) in colorectal carcinoma (CRC) compared to adjacent healthy tissue. This study aims to investigate the molecular mechanisms that mediate CRC colonization by Fn. Using the orthotopic Colon-26 colorectal cancer model, we found that intravascular injected Fn colonizes CRC more than adjacent healthy tissue. Fusobacterial localization in the colon is tumor-dependent, as injected fusobacteria were undetected in the colons of tumor-free mice. CRC colonization is species specific as the gram-negative, anaerobe and periodontitis-related pathogen Prophyromonas gingivalis, which was shown to be abundant in oral tumors failed to colonize CRC. Higher levels of D-galactose-β(1-3)-N-acetyl-D-galactosamine (Gal-GalNAc) are known to be detected in CRC. We recently identified the fusobacterial Fap2 outer-surface protein as a galactose binding lectin, suggesting that it might promote binding of fusobacteria to CRC. A fluorescent-labeled Peanut Agglutinin lectin (PNA) detected more Gal-GalNAc in human and mouse CRC compared to adjacent healthy tissues. Binding of FITC-labeled Fn corresponded with the levels of Gal-GalNAc and colocalized with Gal-GalNAc in the tumor. Flow cytometry revealed that Fap2-deficient Fn mutants are impaired in binding to CRC cell lines compared with their WT parent. Soluble GalNAc inhibited the binding of PNA and WT Fn to CRC cells in a dose-dependent manner, but did not affect the residual CRC binding of fap2 mutated Fn. Furthermore, in the colorectal cancer murine model, tumor colonization by Fap2-deficient Fn mutants was significantly lower than that of the Fap2 sufficient parental strain. Our results demonstrate that the fusobacterial Fap2 lectin binds to Gal-GalNAc on CRC and mediates the tumor-specific attachment of Fn. Understanding the interaction of Fn with CRC, may enable future development of novel diagnostic and therapeutic agents for this disease. Citation Format: Jawad H. Abed, Johanna Emgård, Stella Chaushu, Wendy Garrett, Gilad Bachrach. Gal-GalNAc overexpressed in colorectal carcinoma mediates attachment and colonization of Fusobacterium nucleatum utilizing the Fap2 lectin. [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 3300.

Effect of High-Intensity Focused Ultrasound on Drug Release from Doxorubicin-Loaded PEGylated Liposomes and Therapeutic Effect in Colorectal Cancer Murine Models

The goal of the study described here was to evaluate the use of high-intensity focused ultrasound (HIFU) in drug release and its application in cancer therapy. HIFU was set to minimize hyperthermia, particularly non-specific hyperthermia, of exposed areas. An in vitro temperature-sensitive hydrogel phantom model determined the parameters of HIFU under mild condition settings (spatial average temporal average intensity [ISATA] = 83.35 W/cm2). PEGylated liposomal indocyanine green (LCLP-ICG) and PEGylated liposomal doxorubicin (LCLP-Dox) were prepared with the same mole ratio to allow direct comparison of drug release in vitro and in vivo. We induced drug release with HIFU treatment using LCLP-ICG coupled with optical imaging in vitro and in vivo. The size distribution changes in LCLP-ICG in vitro and fluorescence intensity changes in ICG after intra-tumoral injection of LCLP-ICG into CT26 solid tumors in vivo followed by HIFU confirmed the feasibility of the system. We validated the therapeutic effect of HIFU treatment of the CT26 mouse tumor model. The tumor growth rate was significantly reduced (p < 0.05) only in the group administered LCLP-Dox followed by cycles of HIFU treatment, and the chemotherapy of the CT26 solid tumors was found to be highly efficient.

Abstract 2300: LIN28 cooperates with Wnt signaling to drive invasive intestinal and colorectal adenocarcinoma in mouse and human

Abstract Despite extensive investigation into the molecular basis of tumor development, colorectal cancer (CRC) remains a major contributor to cancer-related mortality. LIN28A and LIN28B are highly related RNA-binding proteins that influence development, tissue regeneration and oncogenesis. Here we demonstrate that overexpression of LIN28 drives invasive intestinal adenocarcinoma and cooperates with the Wnt pathway to promote tumor initiation and progression in murine models. Importantly, conditional withdrawal of LIN28 reduced tumor volume and increased tumor differentiation, indicating that LIN28 contributes to tumor maintenance. Furthermore, co-expression of a LIN28-resistant form of the let-7 microRNA reduced tumor burden. We detected aberrant expression of LIN28 in 38% of a large series of tumor samples from human CRC, and LIN28 expression levels were associated with invasive tumor growth pattern. Our robust late-stage CRC murine model demonstrates strong roles for LIN28 in promoting CRC initiation, growth and progression, and suggests the therapeutic potential in targeting the LIN28/let-7 pathway. Citation Format: Ho-Chou Tu, Sarah Schwitalla, Zhirong Qian, Grace LaPier, Alena Yermalovich, Yuan-Chieh Ku, Shann-Ching Chen, Srinivas R. Viswanathan, Hao Zhu, Reiko Nishihara, Kentaro Inamura, Sun A. Kim, Reppi Morikawa, Kosuke Mima, Yasutaka sukawa, Juhong Yang, Gavin Meredith, Charles S. Fuchs, Shuji Ogino, George Q. Daley. LIN28 cooperates with Wnt signaling to drive invasive intestinal and colorectal adenocarcinoma in mouse and human. [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 2300. doi:10.1158/1538-7445.AM2015-2300

PWE-373 Volatile organic compound (VOC) profiles as indicators of early lesions in murine colon carcinogenesis

<h3>Introduction</h3> Patients with inflammatory bowel disease (IBD) are at increased risk for colorectal cancer (CRC). IBD-associated CRC can be summarised as an inflammation-dysplasia-carcinoma sequence. Much effort has been spent on identifying morphologically distinctive pre-invasive mucosal lesions to help elucidate the early steps of CRC. These efforts have led to the characterisation of so-called mucin-depleted foci (MDF), formed by dysplastic crypts devoid of mucins. A metabolomics-based approach may provide a non-invasive strategy to identify volatile biomarkers of CRC, therefore improving both the early detection of CRC and patient prognosis. <h3>Method</h3> An IBD-associated CRC murine model was used. C57BL/6 female mice were housed individually and were administered one dose of 12.5mg/kg azoxymethane (AOM). Next, mice were orally exposed to 1.5% DSS for 5 days followed by 16 days ordinary water. This DSS cycle was repeated twice with animals sacrificed 12 days after final cycle. There were 2 control groups: untreated mice (<i>n = 6</i>) and mice treated with cycles of DSS alone (<i>n = 6</i>). Faecal samples were collected weekly and tissues were taken for histological analysis upon necropsy. Headspace gas surrounding samples was collected using a CAR/PDMS/DVB SPME fibre before analysis by GC-MS. Chromatograms were analysed and data were processed in-house using AMDIS and Metab. A student’s <i>t</i>-test was performed on samples collected at week 10 (<i>p &lt; 0</i>.01). A time series analysis (two-way ANOVA) was performed on samples collected at weeks 1, 4, 7 and 10, using MetATT. <h3>Results</h3> All animals treated with AOM/DSS showed signs of pre-malignancy, visualised by Alcian blue staining of colonic sections. Signs included hyperplasic and occasionally, dysplastic crypts and MDF reported by an accredited murine pathologist. Faecal VOC analysis at week 10 yielded 93 compounds, 11 of which were significantly different between the two groups (<i>p &lt; 0</i>.01). There was a significant increase in the abundance and prevalence of methyl ketones and aldehydes in treated mice and a time series analysis provided further evidence for these changes over time in VOC profiles. A PCA plot was able to clearly distinguish between untreated and treated mice based on VOCs present in the headspace of faecal samples. Furthermore, the specific compounds that were identified and differed between AOM/DSS and DSS groups may be markers of pre-malignancy. <h3>Conclusion</h3> We have shown that the early lesions of colitis-associated CRC are associated with significant metabolic alterations in the faeces of mice. Markers of chronic inflammation were found. In addition other VOCs were found in AOM/DSS treated mice which had premalignant changes in the colon. These results provide a strong rationale for future studies in humans. <h3>Disclosure of interest</h3> None Declared.

LIN28 cooperates with WNT signaling to drive invasive intestinal and colorectal adenocarcinoma in mice and humans.

Colorectal cancer (CRC) remains a major contributor to cancer-related mortality. LIN28A and LIN28B are highly related RNA-binding protein paralogs that regulate biogenesis of let-7 microRNAs and influence development, metabolism, tissue regeneration, and oncogenesis. Here we demonstrate that overexpression of either LIN28 paralog cooperates with the Wnt pathway to promote invasive intestinal adenocarcinoma in murine models. When LIN28 alone is induced genetically, half of the resulting tumors harbor Ctnnb1 (β-catenin) mutation. When overexpressed in Apc(Min/+) mice, LIN28 accelerates tumor formation and enhances proliferation and invasiveness. In conditional genetic models, enforced expression of a LIN28-resistant form of the let-7 microRNA reduces LIN28-induced tumor burden, while silencing of LIN28 expression reduces tumor volume and increases tumor differentiation, indicating that LIN28 contributes to tumor maintenance. We detected aberrant expression of LIN28A and/or LIN28B in 38% of a large series of human CRC samples (n = 595), where LIN28 expression levels were associated with invasive tumor growth. Our late-stage CRC murine models and analysis of primary human tumors demonstrate prominent roles for both LIN28 paralogs in promoting CRC growth and progression and implicate the LIN28/let-7 pathway as a therapeutic target.

Monitoring Anti-Angiogenic Therapy in Colorectal Cancer Murine Model using Dynamic Contrast-Enhanced MRI — Comparing Pixel-by-Pixel with Region of Interest Analysis

Sorafenib is a multi-kinase inhibitor that blocks cell proliferation and angiogenesis. It is currently approved for advanced hepatocellular and renal cell carcinomas in humans, where its major mechanism of action is thought to be through inhibition of vascular endothelial growth factor and platelet-derived growth factor receptors. The purpose of this study was to determine whether pixel-by-pixel analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is better able to capture the heterogeneous response of Sorafenib in a murine model of colorectal tumor xenografts (as compared with region of interest analysis). MRI was performed on a 9.4 T pre-clinical scanner on the initial treatment day. Then either vehicle or drug were gavaged daily (3 days) up to the final image. Four days later, the mice were again imaged. The two-compartment model and reference tissue method of DCE-MRI were used to analyze the data. The results demonstrated that the contrast agent distribution rate constant (K(trans)) were significantly reduced (p < 0.005) at day-4 of Sorafenib treatment. In addition, the K(trans) of nearby muscle was also reduced after Sorafenib treatment. The pixel-by-pixel analysis (compared to region of interest analysis) was better able to capture the heterogeneity of the tumor and the decrease in K(trans) four days after treatment. For both methods, the volume of the extravascular extracellular space did not change significantly after treatment. These results confirm that parameters such as K(trans), could provide a non-invasive biomarker to assess the response to anti-angiogenic therapies such as Sorafenib, but that the heterogeneity of response across a tumor requires a more detailed analysis than has typically been undertaken.