Orthotopic Colon Cancer Model Research Articles

Accurate Co-Localization of Luciferase Expression and Fluorescent Anti-CEA Antibody Targeting of Liver Metastases in an Orthotopic Mouse Model of Colon Cancer.

The present study aimed to validate the accuracy of a tumor-specific antibody to target liver metastases of colorectal cancer. A humanized anti-CEA antibody conjugated to a fluorescent dye (M5A-IR800) was tested for targeting human colorectal cancer liver metastases (CRLMs) expressing luciferase in an orthotopic mouse model. Orthotopic mouse models of CRLMs were established by implanting fragments of a luciferase-expressing human colorectal cancer cell line, LS174T, in the liver of nude mice. Mice received 50 µg M5A-IR800 72 h prior to imaging. To test co-localization, bioluminescence imaging was performed using D-luciferin, which was given via intraperitoneal injection just prior to imaging. Tumors were able to be visualized non-invasively through the skin with the luciferase-luciferin signal. Intra-abdominal imaging showed accurate labeling of CRLMs with M5A-IR800, which co-localized with the luciferase-luciferin signal. The present results validate the accuracy of a tumor-specific anti-CEA antibody in targeting liver metastases of colorectal cancer.

Jiedu Xiaozheng Yin Inhibits the Progression of Colitis Associated Colorectal Cancer by Stimulating Macrophage Polarization Towards an M1 Phenotype via the TLR4 Pathway.

To investigate the effect of Jiedu Xiaozheng Yin (JXY) on the polarization of macrophages in colitis-associated colon cancer (CAC). An orthotopic model of CAC was established to monitor changes in the pathological state of mice. Colon length, number of colon tumors were recorded, and indices for liver, spleen, and thymus were calculated. Hematoxylin and eosin (H&E) staining was employed to observe intestinal mucosal injury and tumor formation. Immunohistochemistry (IHC) staining was utilized to investigate the effect of JXY on M1 and M2 polarization of macrophages in the colonic mucosa of CAC mice. For in vitro experiments, RT-qPCR (Reverse Transcription-quantitative PCR) and flow cytometry were used to observe the effect of JXY on various M1-related molecules such as IL-1β, TNF-α, iNOS, CD80, CD86, and its phagocytic function as well as M2-related molecules including Arg-1, CD206, and IL-10. Subsequently, after antagonizing the TLR4 pathway with antagonists (TAK242, PDTC, KG501, SR11302, LY294002), the expression of IL-6, TNF-α, iNOS, and IL-1β mRNA were detected by RT-qPCR. In vivo experiments, the results showed that JXY improved the pathological condition of mice in general. And JXY treatment decreased the shortening of colon length and number of tumors as compared to non-treated CAC mice. Additionally, JXY treatment improved the lesions in the colonic tissue and induced a polarization of intestinal mucosal macrophages towards the M1 phenotype, while inhibiting polarization towards the M2 phenotype. In vitro experiments further confirmed that JXY treatment promoted the activation of macrophages towards the M1 phenotype, leading to increased expression of IL-1β, TNF-α, iNOS, CD80, CD86, as well as enhanced phagocytic function. JXY treatment concomitantly inhibited the expression of M2-phenotype related molecules Arginase-1 (Arg-1), CD206, and IL-10. Furthermore, JXY inhibited M1-related molecules such as IL-6, TNF-α, iNOS, and IL-1β after antagonizing the TLR4 pathway. Obviously, JXY could exhibit inhibitory effects on the development of colon tumors in mice with CAC by promoting M1 polarization through TLR4-mediated signaling and impeding M2 polarization of macrophages.

Probiotics formulation and cancer nanovaccines show synergistic effect in immunotherapy and prevention of colon cancer

Probiotics play essential roles in immune modulation. Combining probiotics with cancer vaccines potentially can achieve a synergistic effect. To maximize the efficacy of probiotics, proper probiotics formulation is necessary. Herein, Lactobacillus rhamnosus and Bifidobacterium longum are coated with lipid membrane to achieve the goal of losing less activity and bettering colonization in colon. In the subcutaneous transplanted colon cancer mouse model, probiotics formulation showed potent preventive and therapeutic efficacy, and the efficacy could be further improved by combining with cancer nanovaccines. Probiotics formulation can perform as immune adjuvants to enhance the innate immune response or as in-situ cancer vaccines. In the study of preventing chemical-induced orthotopic colon cancer model, probiotics formulation alone efficiently reduced tumor number in colon and the efficacy is improved by combining with cancer nanovaccines. All in all, the studies demonstrated that probiotics formulation can assist to maximize the efficacy of cancer nanovaccines.

Abstract 4235: Obesity drives inflammation and metabolic reprogramming in an orthotopic mouse model of early colon cancer

Abstract Obesity is strongly associated with colon cancer incidence and, in animal models, promotes colon cancer growth and progression. Mounting evidence indicates that circulating growth factors and chronic inflammation are procancer factors likely mediating this relationship. While obesity blunts antitumor immunity in many cancer types, how obesity-driven inflammation and reduced antitumor immunity may cooperate to promote colon cancer progression is not yet clear. Here we used a murine syngeneic orthotopic transplantation model of colon cancer to profile changes driven by diet-induced obesity (DIO) in the immune and cancer cell compartments of the tumor using digital spatial profiling and RNA sequencing. 7-9-week-old male and female C57BL/6 mice remained on either a 10 kcal% fat diet (control, n=34) or a 60 kcal% fat diet (DIO, n=27) for at least 19 weeks. 700 Apc-null;KrasG12D/+;Trp53-null;Smad4-null;tdTomato (i.e., AKPS) organoids were transplanted into the colonic wall of control and DIO mice via colonoscopy-guided injection. Tumors were excised after four weeks of growth, an early time point to assess changes between diet groups independent of tumor size differences or weight loss associated with tumor growth. RNA sequencing was performed on RNA extracted from tumoral CD45+ and EpCAM+ cell fractions isolated using Milltenyi MicroBeads. DIO mice weighed more than controls (males: controls 37.0 g ± 5.1 vs. DIO 47.4 g ± 4.3; females: controls 26.4 g ± 3.7 vs. DIO 45.9 g ± 9.7) and had more mesenteric fat surrounding the colon (males: controls 388 mg ± 217 vs. DIO 577 mg ± 185; females: controls 201 mg ± 143 vs 1176 mg ± 589). Leptin, resistin, and plasminogen activator inhibitor-1 were significantly elevated in the serum of DIO mice relative to control mice. Tumor weight did not differ between groups. Gene set enrichment analysis demonstrated that tumor cells from DIO mice were significantly enriched for pathways related to inflammation (INFLAMMATORY_RESPONSE, IL6_JAK_STAT3_SIGNALING), glucose and lipid metabolism (GLYCOLYSIS, FATTY_ACID_METABOLISM), and proliferation (E2F_TARGETS, G2M_CHECKPOINT). Within the CD45+ transcriptomic profiles, Tumor Immune Estimation Resource (TIMER2.0) indicated an increase in M0- and M1-like macrophages and B cells in tumors from DIO compared with control mice. Analysis of whole tumor sections from DIO mice showed significantly reduced CD3+ cells by immunofluorescence and more Ki67+ CD45+ immune cells by digital spatial profiling relative to tumors from control mice. Taken together, obesity drives an inflammatory profile in both the immune and epithelial cell populations of AKPS murine tumors, which is associated with increased markers of proliferation. Future studies will address whether inflammatory signals from the mesenteric fat adjacent to the colon tumors may contribute to obesity-driven tumor inflammation, and thereby to colon cancer progression. Citation Format: Elaine M. Glenny, Babak Mirminachi, Tori L. McFarlane, Jatin Roper, Stephen D. Hursting. Obesity drives inflammation and metabolic reprogramming in an orthotopic mouse model of early colon cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4235.

Focused ultrasound restrains the growth of orthotopic colon cancer via promoting pyroptosis.

Focused ultrasound (FUS) is a non-invasive tumor therapy technology emerging in recent years, which can treat various solid tumors. However, it is unclear whether FUS can affect the pyroptosis of colon cancer (CC) cells. Here, we analyzed the effect of FUS on pyroptosis in the orthotopic CC model. After an orthotopic CC mouse model was constructed by injecting CT26-Luc cells, BABL/C mice were allocated to the normal, tumor, FUS, and FUS + BAY11-7082 (pyroptosis inhibitor) groups. We monitored the tumor status of the mice through in vivo fluorescence image analysis. The histopathological injury of the intestinal tissue and the expression of IL-1β, IL-18, caspase-recruitment domain (ASC), cleaved caspase-1, gasdermin D (GSDMD), and NLRP3 of the CC tumors were examined utilizing hematoxylin and eosin staining, immunohistochemical assay, and Western blot. FUS restrained the fluorescence intensity of the tumors in orthotopic CC mice, while FUS-mediated suppression of the bioluminescent signal of the tumors was alleviated by BAY11-7082. FUS was found to relieve the injury of the intestinal tissues in CC mice as revealed by morphology. Furthermore, the expressions of IL-1β, IL-18, GSDMD, ASC, cleaved caspase-1, and NLRP3 of the CC tumors in the FUS group were higher than those in the tumor group, while BAY11-7082 addition partly reversed the FUS's effects on orthotopic CC model mice. Our results pointed out that FUS presented anti-tumor activity in experimental CC, and its mechanism was correlated with the promotion of pyroptosis.

An acetylated mannan isolated from Aloe vera induce colorectal cancer cells apoptosis via mitochondrial pathway

The anti-cancer effects of Aloe vera barbadensis extract C (AVBEC) have been demonstrated in a previous study. However, the specific functional ingredient and mechanism remain undefined. This study aimed to evaluate the function and associated mechanisms of purified polysaccharide (ABPA1) from AVBEC on colorectal cancer. Here, we identify that ABPA1 can induce colorectal cancer apoptosis. In vivo, ABPA1 significantly suppressed tumor growth in an orthotopic colon cancer model. Mechanistically, ABPA1 alters mitochondrial membrane permeability by promoting Bax translocation while causing cytochrome-c release, which initiates the caspase cascade reaction. Additionally, we found that ABPA1 exerted distinct impacts on the mitochondrial metabolism of colorectal cancer cells. Our study elucidated the mechanism by which the polysaccharide ABPA1 induces apoptosis in colorectal cancer cells through the regulation of Bax and cytochrome-c mediated mitochondrial pathway, indicating that ABPA1 may be developed as a mitochondrial-targeting anti-cancer drug.

PUMILIO proteins promote colorectal cancer growth via suppressing p21

PUMILIO (PUM) proteins belong to the highly conserved PUF family post-transcriptional regulators involved in diverse biological processes. However, their function in carcinogenesis remains under-explored. Here, we report that Pum1 and Pum2 display increased expression in human colorectal cancer (CRC). Intestine-specific knockout of Pum1 and Pum2 in mice significantly inhibits the progression of colitis-associated cancer in the AOM/DSS model. Knockout or knockdown of Pum1 and/or Pum2 in human CRC cells result in a significant decrease in the tumorigenicity and delayed G1/S transition. We identify p21/Cdkn1a as a direct target of PUM1. Abrogation of the PUM1 binding site in the p21 mRNA also results in decreased cancer cell growth and delayed G1/S transition. Furthermore, intravenous injection of nanoparticle-encapsulated anti-Pum1 and Pum2 siRNAs reduces colorectal tumor growth in murine orthotopic colon cancer models. These findings reveal the requirement of PUM proteins for CRC progression and their potential as therapeutic targets.

Shed syndecan-2 enhances colon cancer progression by increasing cooperative angiogenesis in the tumor microenvironment

Although shed syndecan-2 potentiated the tumorigenic activities of colon cancer cells, how shed syndecan-2 increases this tumorigenic potential remains unclear. Using an orthotopic mouse model of colon cancer, we show that shed syndecan-2 increases colon cancer progression by cooperatively promoting angiogenesis. Co-administration with a synthetic peptide of shed syndecan-2 (S2LQ) enhanced the survival and tumor engraftment of luciferase-expressing CT26 colon adenocarcinoma cells orthotopically implanted into the cecum of BALB/c mice. Intravenous injection of S2LQ further enhanced the growth of orthotopic tumors in the cecum, with increases in the tissue infiltration of macrophages and the formation of blood vessels, mainly in peripheral layers of the tumor facing the stroma. Furthermore, S2LQ stabilized HIF1α and enhanced the VEGF expression in human colon cancer cell lines, and increased the migration of RAW 264.7 murine macrophage cells and bone marrow-derived macrophages. Finally, S2LQ increased the tube formation of vascular endothelial cells in vitro. Together, these data demonstrate that shed syndecan-2 enhances tumorigenic activity by increasing the crosstalk of cancer cells with tumor-associated macrophages and endothelial cells to enhance angiogenesis for colon cancer progression in the tumor microenvironment.

Rapid tumor-labeling kinetics with a site-specific near-infrared anti-CEA nanobody in a patient-derived orthotopic xenograft mouse model of colon cancer.

Nanobodies are the smallest biologic antigen-binding fragments derived from camelid-derived antibodies. Nanobodies effect a peak tumor signal within minutes of injection and present a novel opportunity for fluorescence-guided surgery (FGS). The present study demonstrates the efficacy of an anti-CEA nanobody conjugated to near-infraredfluorophore LICOR-IRDye800CW for rapid intraoperative tumor labeling of colon cancer. LS174T human colon cancer cells or fragments of patient-derived colon cancer were implanted subcutaneously or orthotopically in nude mice. Anti-CEA nanobodies were conjugated with IRDye800CW and 1-3 nmolwere injected intravenously. Mice were serially imaged over time. Peak fluorescence signal and tumor-to-background ratio (TBR) were recorded. Colon cancer tumors were detectable using fluorescent anti-CEA nanobody within 5 min of injection at all three doses. Maximal fluorescence intensity was observed within 15 min-3 h for all three doses with TBR values ranging from 1.3 to 2.3. In the patient-derived model of colon cancer, fluorescence was detectable with a TBR of 4.6 at 3 h. Fluorescent anti-CEA nanobodies rapidly and specifically labeled colon cancer in cell-line-based and patient-derived orthotopic xenograft (PDOX) models. The kinetics of nanobodies allow for same day administration and imaging. Anti-CEA-nb-800 is a promising and practical molecule for FGS of colon cancer.

Abstract 2926: CT26.WT-luc orthotopic syngeneic tumor model of colon cancer: development and immunotherapy response

Abstract Colorectal cancer (CRC) is a major contributor to the whole of cancer as a disease, representing 10% of all cases of cancer. Recent clinical studies and FDA approvals demonstrate strong possibilities for the future of immunotherapy in the treatment of CRC. Highly translational preclinical models of the disease are required to assess the effectiveness of novel immuno-oncology agents. The CT26.WT murine colon carcinoma model is a widely used syngeneic tumor model to evaluate the preclinical efficacy of immuno-oncology agents. Subcutaneous tumor models are limited in translatability compared to the orthotopic implant site including differential stromal interactions, immune cell infiltrate, and response to immunotherapy. We present the development of a robust murine orthotopic colon tumor model (CT26.WT-luc) assessed by bioluminescence imaging (BLI) and assessed for response to common checkpoint targets. All animal work was performed in an AAALAC accredited facility, in alignment with applicable animal welfare regulations and with predetermined humane euthanasia criteria on all studies. Subcutaneous CT26.WT-luc tumors were dissected into fragments and grafted onto the cecum of naïve Balb/c mice. Mice were subjected to BLI twice weekly for four weeks for longitudinal monitoring of tumor growth. The tumor engraftment rate was 95% based on BLI and necropsy, no spontaneous regressions were observed. The BLI derived tumor volume doubling time was 1.5 days and the median time on study was 21 days. Common clinical observations associated with disease progression were abdominal distension due to tumor growth and bodyweight gain. Necropsy revealed large primary masses attached to the cecum with large vascular involvement, and small nodules on the liver and abdominal wall. To assess the model response to immunotherapy, Balb/c mice bearing orthotopic CT26.WT-luc tumors were treated by intraperitoneal administration of 10mg/kg isotype control, anti-PD-L1, anti-CTLA-4 or anti-PD-1 twice weekly for two weeks (Bio X Cell). Administration of anti-PD-L1 resulted in one complete regression. Anti-CTLA-4 treatment resulted in a day 23 ΔT/ΔC of 0.1% and five partial regressions with no visibly detectable disease at necropsy. Administration of anti-PD-1 did not result in regressions or tumor free survivors. Administration of either anti-PD-L1 or anti-CTLA-4 provided an increase of life span over isotype control of 13 and 24 days, respectively. Terminal necropsy revealed no evidence of tumors or other lesions in 1 out of 8 animals administered anti-PD-L1, and 5 out of 8 animals administered anti-CTLA-4. This model represents a powerful tool with translational potential for assessing the efficacy of novel immune modulating agents with the possibility of combination therapy. Assessment of tumor response, cell and molecular differences between subcutaneous and orthotopic CT26.WT-luc tumors is ongoing. Citation Format: Patrick Allison, Derrik Germain, Meredith Baugher, Maryland Franklin. CT26.WT-luc orthotopic syngeneic tumor model of colon cancer: development and immunotherapy response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2926.

Abstract 2851: Trop-2 inactivates E-cadherin for metastatic diffusion in the absence of EMT

Abstract Trop-2 is a type I transmembrane glycoprotein, which is overexpressed in the majority of carcinomas, where it drives tumor cell proliferation. In its mature, glycosylated/functionally-competent form, Trop-2 associates with worse prognosis. A global quest was conducted for identifying decisive drivers of cancer metastasis. Cancer cell spheroids, wound healing and cell aggregation assays were utilized to assess cell-cell adhesion capacity. Immunofluorescence confocal microscopy and flow cytometry analysis were utilized to quantify expression of target signaling proteins, IHC analysis quantified the expression of target molecules in primary tumors and metastases. Pre-clinical models of orthotopic growth of colon cancer and metastatic diffusion to the liver were utilized. Xenotransplant transcriptome profiling analyzed transcription of EMT-related determinants. This led us to identify Trop-2 as a unique upregulated gene in colon cancer metastasis. Trop-2 was here shown to bind highly-expressed E-cadherin at the cell membrane. Trop-2 binding released E-cadherin from the cytoskeleton, inhibited cell-cell adhesion functions and activated signaling through β-catenin. This occurred in the absence of transcriptional downregulation of the CDH1 gene by EMT-associated transcription factors. The Trop-2/E-cadherin/β-catenin program was shown to lead to anti-apoptotic signaling, increased cell migration and enhanced cancer cell survival. In an orthotopic model of colon cancer, Trop-2 caused metastatic diffusion to the liver. The Trop-2-led E-cadherin-inactivation metastasis program was then found to induce metastatic relapse and shorter overall survival of colon cancer patients. Corresponding impact was indicated on breast, colon, ovary, uterus, stomach cancer metastatic diffusion, for broad impact on metastatic diffusion in human cancer. Acknowledgments:Support was provided by grants of Italian Ministry of Development (MI01_00424) and of University and Research (SCN_00558). M.T. was supported by the Programma Per Giovani Ricercatori “Rita Levi Montalcini” (Grant PGR12I7N1Z). Citation Format: Saverio Alberti, Emanuela Guerra, Valeria Relli, Rossano Lattanzio, Martina Ceci, Khouloud Boujnah, Valeria Garbo, Antonino Moschella, donato F. Altomare, Raffaella Depalo, Marco Trerotola. Trop-2 inactivates E-cadherin for metastatic diffusion in the absence of EMT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2851.

Extracellular vesicles-based pre-targeting strategy enables multi-modal imaging of orthotopic colon cancer and image-guided surgery

BackgroudColon cancer contributes to high mortality rates as the result of incomplete resection in tumor surgery. Multimodal imaging can provide preoperative evaluation and intraoperative image-guiding. As biocompatible nanocarriers, extracellular vesicles hold great promise for multimodal imaging. In this study, we aim to synthesized an extracellular vesicles-based nanoprobe to visualize colon cancer with positron-emission tomography/computed tomography (PET/CT) and near-infrared fluorescence (NIRF) imaging, and investigated its utility in image-guided surgery of colon cancer in animal models.ResultsExtracellular vesicles were successfully isolated from adipose-derived stem cells (ADSCs), and their membrane vesicles were observed under TEM. DLS detected that the hydrodynamic diameters of the extracellular vesicles were approximately 140 nm and the zeta potential was − 7.93 ± 0.24 mV. Confocal microscopy showed that extracellular vesicles had a strong binding ability to tumor cells. A click chemistry-based pre-targeting strategy was used to achieve PET imaging in vivo. PET images and the biodistribution results showed that the best pre-targeting time was 20 h, and the best imaging time was 2 h after the injection of 68 Ga-L-NETA-DBCO. The NIRF images showed that the tumor had clear images at all time points after administration of nanoparticles and the Tumor/Muscle ratio peaked at 20 h after injection. Our data also showed that both PET/CT and NIRF imaging clearly visualized the orthotopic colon cancer models, providing preoperative evaluation. Under real-time NIRF imaging, the tumor location and tumor boundary could be clearly observed.ConclusionsIn brief, this novel nanoprobe may be useful for multi-modal imaging of colon cancer and NIRF image-guided surgery. More importantly, this study provides a new possibility for clinical application of extracellular vesicles as nanocarriers.Graphic

Study on intervention effect of Astragali Radix-Curcumae Rhizoma on growth and metastasis of colon cancer in orthotopic transplantation mice model of colon cancer

Astragali Radix-Curcumae Rhizoma is a classic drug pair mainly used for the treatment of digestive tract-related inflammation and tumors, but the ratio is not fixed in clinical practice. In order to study whether the anti-tumor effect of the drug pair is diffe-rent under different ratios, orthotopic transplantation model of colon cancer was established in mice. Then the principal component analysis(PCA) and cluster analysis(CA) were used to explore the effect of different ratios of the drug pair on the tumor growth and metastasis, and select the optimal ratio of Astragali Radix-Curcumae Rhizoma for anti-colon cancer effect. After administration for 15 days, the body weight of colon cancer mice with the tumor removed, the tumor volume and the number of liver metastases were mea-sured; the pathological changes of tumor tissue and liver tissue were observed by HE staining. At the same time, Western blot method was used to detect the protein expression level of tumor growth-related indicators in tumor tissue(Ki67, HBP1, AFP) and tumor metastasis-related indicators in liver tissue(β-catenin, E-cadherin, vimentin, p53) of the tumor-bearing mice. Subsequently, PCA and CA were used to select the optimal ratio of Astragali Radix-Curcumae Rhizoma for anti-colon cancer effect. The experimental results showed that different ratios of Astragali Radix-Curcumae Rhizoma inhibited tumor growth and metastasis to varying degrees. The ratio at 1∶1 of Astragali Radix-Curcumae Rhizoma had the best inhibitory effect on tumor growth, and the 2∶1 ratio group had the best effect on inhibiting liver metastasis and improving weighed loss. Astragali Radix-Curcumae Rhizoma significantly up-regulated the protein expression of HBP1 in tumor tissue of colon cancer mice, and significantly down-regulated the protein expression of Ki67 and AFP in tumor tissue; meanwhile, Astragali Radix-Curcumae Rhizoma significantly up-regulated the protein expression of E-cadherin in liver tissue of colon cancer mice, and significantly reduced the protein expression of β-catenin, vimentin and p53 in liver tissue. PCA results showed that the first three groups in the Astragali Radix-Curcumae Rhizoma compatibility group that were closer to the sham operation group were in the order of 2∶1, 1∶1 and 3∶2, among which the center distance of the 2∶1 group was the shortest from the sham operation group, indicating that the ratio 2∶1 of Astragali Radix-Curcumae Rhizoma had the best intervention effect on colon cancer in mice, consistent with the commonly used clinical proportion. CA results showed that 11 groups of colon cancer mice were classified into 3 categories: Astragali Radix-Curcumae Rhizoma compatibility group, sham operation group and model group, which was consistent with the theory. The results of this study provide a basis for more effective clinical application of Astragali Radix-Curcumae Rhizoma in the treatment of colon cancer, and provide new ideas for the development of classic drug pairs.

Gold Nanoparticles Inhibit Colorectal Cancer Liver Metastasis through Inhibiting the TGF-β Pathway

Introduction: The application of gold nanoparticles (AuNPs) to the management of cancer is currently the new breakthrough in cancer research. However, the role of AuNPs on tumor growth and metastasis in colon cancer and the mechanism by which AuNPs regulate tumor growth and liver metastasis in colorectal cancer (CRCLM) are unclear. Method: We established two TGF-β inducible luciferase colon cancer cell line and orthotopic colon cancer and liver metastasis animal models. We also overexpressed or knockdown Smad4, an important transduction factor of the TGF-β signaling pathway, to explore the molecular mechanism by which AuNPs regulate CRCLM. Results: AuNPs inhibited TGF-β secretion of colon cancer, and downregulated the downstream reporter genes of TGF-β signaling pathway. AuNPs inhibited cell proliferation, migration and invasion in vitro, and reduced tumor growth and liver metastasis in vivo. ERK, P38 MAPK and AKT was inactivated by AuNPS, leading to down-regulation of VEGF secretion and Vimentin while up-regulation of E-Cadherin. When Smad4 was knockdown, cells were significantly more sensitive to AuNPs treatment. The TGF-β inducible luciferase cell line were established, and used for liver metastasis animal models. Mice were treated with the TGF-β receptor inhibitors, and the results showed that this model could observe the activation of TGF-β signaling pathway as well as tumor progression in vivo. Conclusions: These results provided evidences that AuNPs inhibit CRCLM through inhibiting the TGF-β pathway. This research provided theoretical evidences for the clinical use of AuNPs for the treatment of colon cancer or CRCLM.

Metabonomics study on orthotopic transplantion mice model of colon cancer treated with Astragalus membranaceus-Curcuma wenyujin in different proportions via UPLC-Q-TOF/MS

Metabolomics, an important part of systems biology, can reveal the complex pathogenesis of many diseases and mechanism of Chinese materia medica (CMM). Astragalus membranaceus-Curcuma wenyujin (AC) was a classic drug pair that has a good clinical effect on gastrointestinal inflammation and many tumors. Our previous research proved that AC can inhibit tumor growth and metastasis especially the colorectal cancer (CRC), also promote the normalization of tumor blood vessels, but its optimal ratio and the specific mechanism is still not clear. In this study, colon cancer mice of orthotopic transplantion model was used to screen the best proportion, UPLC-Q-TOF/MS metabolomics analysis method was established to explore the pathogenesis of colon cancer and the molecular mechanism of AC. The correlation analysis of metabolite changes and tumor growth was analyzed by R language. The result showed that AC at the ratio of 2:1 showed the best effect on inhibiting tumor growth, also the liver and spleen metastasis rate. A total of 23 potential biomarkers were detected in the serum of colon cancer mice by the analysis of Progenesis QI (Version 2.4) software. Among this, 11 metabolites including purines, steroids, phytosphingosine and l-palmitoylcarnitine were up-regulated in CC mice, while 12 metabolites like amino acids, deoxyribose and dihydrobiopterin were down-regulated in CC mice. After the treatment of AC for 15 days, 8 biomarkers were up-regulated, and 9 biomarkers down-regulated. Especially, AC at the ratio of 2:1 showed a significant callback effect on metabolic biomarkers, such as hypoxanthine, xanthosine, 7-methylxanthine, all-trans-retinoic acid, dihomo-γ-linolenic acid. 8 metabolic pathways: Aminoacyl-tRNA biosynthesis, Nicotinate and nicotinamide metabolism, Phenylalanine, tyrosine and tryptophan biosynthesis, Valine, leucine and isoleucine biosynthesis, Phenylalanine metabolism, Caffeine metabolism, Retinol metabolism, Alanine, aspartate and glutamate metabolism were selected as the model group disturbed metabolic pathways after the enrichment of MetaboAnalyst 4.0 online analysis software. And compared with the model group, Valine, leucine and isoleucine biosynthesis, Aminoacyl-tRNA biosynthesis, Caffeine metabolism pathway and Retinol metabolism pathways were altered after the intervention of AC. The correlation analysis results showed that various endogenous metabolites in serum have a strong correlation with tumor weight, such as hypoxanthine, which provides a basis for the selection of clinical markers. The results showed that AC can partially regulate metabolic disorder of CC mice by reversing the changes of metabolites, so as to inhibit the growth and metastasis of colon cancer, especially at the ratio of 2:1. These findings can provide a scientific basis for exploring the diagnostic biomarkers of colon cancer, and for clinical application of AC in the treatment of CRC program.

Mo1688 LOCAL PHOTOTHERMAL THERAPY USING NANO FUNCTIONALIZED SELF EXPANDABLE METAL STENT IN AN ORTHOTOPIC MOUSE MODEL OF HUMAN COLON CANCER

Self-expandable stents for obstructing colorectal cancer offer an alternative palliative option to operative management. However, stent obstruction from tumor invasion decreases the stent patency and increases the rates of reintervention. Here, we developed a novel gold nanoparticle (GN) coated self-expandable metal stent (SEMS) for local heating induced suppression of tumor growth. The effectiveness was investigated in an orthotopic mouse model of human colon cancer. GN SEMSs (4 mm in diameter and 8 mm in length) were coated using a two-step synthesis process. The GN SEMS’s wire showed no cytotoxicity to human colon cancer cells (HCT-116) in-vitro. An effective local heating dose (55°C) was achieved under near-infrared laser irradiation (0.8 W/cm2) in ex-vivo studies. Subsequently, a red fluorescent protein (RFP) expressing HCT-116 human colon cancer cells were implanted in the submucosa of the colons of 40 nude mice using a microendoscope (Karl Storz, Germany). Mucosal lifting during the procedure indicated successful implantation. Tumor size was assessed by the degree of lumen obstruction on microendoscopy using a 5 points scale ranging from 1 (just detectable tumor) to 5 (tumor occupying more than half of the lumen). After 2 weeks, 30 mice developed tumors that obstructed 25-50% (grade 4) of the colon lumen (Fig. 1). They were randomly divided into 3 groups of 10 mice each; group A: GN SEMSs without laser irradiation, group B: uncoated SEMSs with laser irradiation (0.8 W/cm2), and group C: GN SEMSs with laser irradiation (0.8 W/cm2). Follow up using microendoscopy and in vivo fluorescence imaging was performed to check the tumor growth rate. The mice were sacrificed after one week and histopathological examination using hematoxylin and eosin staining was performed. SEMSs placement and laser irradiation (group B and C) were technically successful in all mice with no immediate complications. Within one week, seven mice died secondary to colonic obstruction (group A = 3, group B = 3, group C = 1), and one died from micro-perforation in group C. Follow up by microendoscopy after one week showed significantly reduced tumor size in group C (mean ± standard deviation, 1.13 ± .35) compared to group A (2.7 ± .49), and group B (2.6 ± .53); p = <.001. Also, the fluorescent signal intensity was significantly lower in group C (3.07 ± 0.83 × 108 p/s/cm2/sr) compared to group A (5.4 ± 0.80 × 108 p/s/cm2/sr), and group B (5.2 ± 0.24 × 108 p/s/cm2/sr); p = <0.001 (Fig. 2). Histopathological examination showed tumor development in the submucosal layer of the colon with smaller tumor sizes in group C compared to group A and B (Fig. 1). Local photothermal therapy using nano-functionalized stents inhibits tumor growth in an orthotopic mouse model of human colon cancer.Figure 2Representative in-vivo fluorescence images showing lower intensity signals in group C compared to group A and B. Time point 1 = before stent placement, 2= immediately after stent placement, and 3 = one week after stent placement.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Effect of Proton Pump Inhibitors on Colorectal Cancer.

Proton pump inhibitors (PPIs) are administered commonly to aged people; however, their effect on colorectal cancer (CRC) has still not been fully elucidated. Here, we examined the effect of PPIs and consequent alkalization on CRC cells. PPI administration alkalized the fecal pH and increased serum gastrin concentration. PPI and pH8 treatment (alkalization) of CMT93 mouse colon cancer cells inhibited cell growth and invasion, increased oxidative stress and apoptosis, and decreased mitochondrial volume and protein levels of cyclin D1 and phosphorylated extracellular signal-regulated kinase (pERK) 1/2. In contrast, gastrin treatment enhanced growth and invasion, decreased oxidative stress and apoptosis, and increased mitochondrial volume and cyclin D1 and pERK1/2 levels. Concurrent treatment with a PPI, pH8, and gastrin increased aldehyde dehydrogenase activity and also enhanced liver metastasis in the BALB/c strain of mice. PPI administration was associated with Clostridium perfringens enterotoxin (CPE) in CRC lesions. CPE treatment activated yes-associated protein (YAP) signals to enhance proliferation and stemness. The orthotopic colon cancer model of CMT93 cells with long-term PPI administration showed enhanced tumor growth and liver metastasis due to gastrin and YAP activation, as indicated by gastrin receptor knockdown and treatment with a YAP inhibitor. These findings suggest that PPI promotes CRC growth and metastasis by increasing gastrin concentration and YAP activation, resulting in gut flora alteration and fecal alkalization. These findings suggest that PPI use in colorectal cancer patients might create a risk of cancer promotion.

Resveratrol and Its Nanoformulation Attenuate Growth and the Angiogenesis of Xenograft and Orthotopic Colon Cancer Models.

Cancer is a multifactorial disorder that induces mortality worldwide, and the colorectal type is the third most common cancer globally. Resveratrol (RSV) is a natural compound with an effective anticancer effect, especially against colorectal cancer, and therefore numerous studies recommended its use in colorectal cancer prevention and treatment. The current study investigated the effect of either RSV or its nanoformulation (NP-RSV) on the growth and vascularity of xenograft and orthotopic mice models in colon cancer (COLO205-luc). Both RSV and NP-RSV induced significant reductions in tumor growth and the hemoglobin percentages of the tumor mass, but NP-RSV showed greater bioavailability and efficacy than RSV. Generally, we recommend using NP-RSV as a therapeutic to control colon cancer.

Photoacoustic Imaging Quantifies Drug Release from Nanocarriers via Redox Chemistry of Dye‐Labeled Cargo

AbstractWe report a new approach to monitor drug release from nanocarriers via a paclitaxel–methylene blue conjugate (PTX‐MB) with redox activity. This construct is in a photoacoustically silent reduced state inside poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles (PTX‐MB@PLGA NPs). During release, PTX‐MB is spontaneously oxidized to produce a concentration‐dependent photoacoustic signal. An in vitro drug‐release study showed an initial burst release (25 %) between 0–24 h and a sustained release between 24–120 h with a cumulative release of 40.6 % and a 670‐fold increase in photoacoustic signal. An in vivo murine drug release showed a photoacoustic signal enhancement of up to 649 % after 10 hours. PTX‐MB@PLGA NPs showed an IC50 of 78 μg mL−1 and 44.7±4.8 % decrease of tumor burden in an orthotopic model of colon cancer via luciferase‐positive CT26 cells.

Pazopanib Inhibits Tumor Growth, Lymph-node Metastasis and Lymphangiogenesis of an Orthotopic Mouse of Colorectal Cancer.

Pazopanib (PAZ) can inhibit tumor progression, but whether PAZ inhibits lymph node metastasis and lymphangiogenesis in colorectal cancer is still unknown. The aim of the present study was to determine the efficacy of PAZ on tumor growth, lymph node metastasis and lymphangiogenesis in an orthotopic nude mouse model in colorectal cancer. CT-26-green fluorescence protein (GFP)-expressing mouse colon cancer cells were injected into nude mice to establish a subcutaneous colorectal cancer model and were treated with saline and PAZ. Additionals subcutaneous tumors were harvested and cut into 5 mm3 fragments, then tumor fragments were implanted orthotopically in the cecum to establish an orthotopic colorectal-cancer nude mouse model. Orthotopic mice were randomized into two groups for the treatment with saline and PAZ, respectively. Tumor width, length and mouse body weight was measured twice a week. The Fluor Vivo imaging system was used to image the GFP. Hematoxylin & eosin staining and immunohistochemical staining was used for histological analysis. PAZ inhibited the growth of subcutaneous colorectal cancer, as wells as orthotopic transplanted colorectal cancer tumors. PAZ suppressed lymph node metastasis and lymphangiogenesis in the orthotopic colon cancer model. No significant changes were observed in the body weight between the control and the mice treated with PAZ. PAZ can inhibit the growth of colorectal cancer and inhibit lymph node metastasis and lymphangiogenesis in orthotopic colon cancer nude mouse models.