Eun-ju Do

Spraying Quantum Dot Conjugates in the Colon of Live Animals Enabled Rapid and Multiplex Cancer Diagnosis Using Endoscopy

The detection of colon cancer using endoscopy is widely used, but the interpretation of the diagnosis is based on the clinicians naked eye. This is subjective and can lead to false detection. Here we developed a rapid and accurate molecular fluorescence imaging technique using antibody-coated quantum dots (Ab-QDs) sprayed and washed simultaneously on colon tumor tissues inside live animals, subsequently excited and imaged by endoscopy. QDs were conjugated to matrix metalloproteinases (MMP) 9, MMP 14, or carcinoembryonic antigen (CEA) Abs with zwitterionic surface coating to reduce nonspecific bindings. The Ab-QD probes can diagnose tumors on sectioned mouse tissues, fresh mouse colons stained ex vivo and also in vivo as well as fresh human colon adenoma tissues in 30 min and can be imaged with a depth of 100 μm. The probes successfully detected not only cancers that are readily discernible by bare eyes but also hyperplasia and adenoma regions. Sum and cross signal operations provided postprocessed images that can show complementary information or regions of high priority. This multiplexed quantum dot, spray-and-wash, and endoscopy approach provides a significant advantage for detecting small or flat tumors that may be missed by conventional endoscopic examinations and bestows a strategy for the improvement of cancer diagnosis.

Western-style diets induce macrophage infiltration and contribute to colitis-associated carcinogenesis.

Background and Aim:  A Western‐style diet (WD) is known to play an important role in inflammatory bowel disease and colon carcinogenesis. The purpose of this study was to understand the role of macrophages in WD‐induced colitis associated with carcinogenesis.

Suppression of colitis-associated carcinogenesis through modulation of IL-6/STAT3 pathway by balsalazide and VSL#3.

Recent studies suggest that the anti‐inflammatory agent balsalazide (BSZ) and probiotic agent VSL#3 have potential therapeutic benefits for the treatment of patients with inflammatory bowel disease. However, their effectiveness in preventing colitis‐associated carcinogenesis (CAC) remains uncertain. The aim of the present study was to determine the chemopreventive effects of BSZ and VSL#3 in the murine azoxymethane (AOM)/dextran sodium sulfate (DSS) model.

Combination of metformin and VSL#3 additively suppresses western-style diet induced colon cancer in mice

&NA; Western‐style diet (WD) and dysbiosis are known to be associated with colonic inflammation, which contributes to carcinogenesis. Metformin (Met) exerts anti‐inflammatory effects to induce AMP‐activated protein kinase (AMPK), resulting in suppressed protein synthesis and reduced cell proliferation. Probiotic VSL#3 (V) modifies microbial composition. We investigated the chemopreventive mechanisms of Met and V in WD‐induced colitis‐associated colon carcinogenesis. Male BALB/c mice were randomly divided into five groups: a control diet (CD) group, WD group, WD+ Met (250 mg/kg/day) group, WD+V (1.3 million bacteria/day) group, and WD+Met+V group. All mice were exposed to azoxymethane (10 mg/kg) followed by 2% dextran sodium sulfate (DSS) for 7 days. Using HCT‐116 human colon cancer cell line, expression of AMPK, extracellular signal‐regulated kinase (ERK), cyclin D1, and Bcl‐2 was investigated and cell cycle arrest was assessed. WD enhanced the severity of colitis and tumor growth compared with CD. The combination of Met and V significantly ameliorated colitis and tumor growth by inhibiting macrophage infiltration and maintaining epithelial integrity. In vitro assays showed that the combination therapy promoted late apoptosis by inhibiting cyclin D1 and Bcl‐2 and activating pro‐apoptotic ERK. A combination therapy with Met and V attenuates tumor growth in a mouse model of WD‐induced colitic cancer, suggesting that this strategy could be useful for the chemoprevention of colon cancer.

Clinically compatible flexible wide-field multi-color fluorescence endoscopy with a porcine colon model

Early detection of structural or molecular changes in dysplastic epithelial tissues is crucial for cancer screening and surveillance. Multi-targeting molecular endoscopic fluorescence imaging may improve noninvasive detection of precancerous lesions in the colon. Here, we report the first clinically compatible, wide-field-of-view, multi-color fluorescence endoscopy with a leached fiber bundle scope using a porcine model. A porcine colon model that resembles the human colon is used for the detection of surrogate tumors composed of multiple biocompatible fluorophores (FITC, ICG, and heavy metal-free quantum dots (hfQDs)). With an ex vivo porcine colon tumor model, molecular imaging with hfQDs conjugated with MMP14 antibody was achieved by spraying molecular probes on a mucosa layer that contains xenograft tumors. With an in vivo porcine colon embedded with surrogate tumors, target-to-background ratios of 3.36 ± 0.43, 2.70 ± 0.72, and 2.10 ± 0.13 were achieved for FITC, ICG, and hfQD probes, respectively. This promising endoscopic technology with molecular contrast shows the capacity to reveal hidden tumors and guide treatment strategy decisions.

Tu1959 Molecular Imaging As a Predictive Diagnostic Method for the Therapeutic Efficacy of Radiotherapy in Xenograft Model of Human Colorectal Cancer

exposed to experimental models of colitis and sporadic or inflammation-associated tumor development and human tissue samples from patients with inflammatory bowel disease (Crohns disease and ulcerative colitis) and sporadic colorectal cancer in comparison to control tissue. Tissue samples were obtained according to ethical guidelines and each patient gave written consent. Following preparation, fresh tissue samples were kept in PBS during multiphoton imaging. Excitation was performed at 800 nm and fluorescence and SHG were detected from 380 to 580 nm using a commercial MPM system. Results: Autofluorescence MPM of control tissue samples provided a detailed visualization of the mucosal layer with subcellular resolution and the possibility to discriminate individual structural components such as collagen filaments. Imaging of deeper tissue layers allowed the visualization of individual resident immune cells in the lamina propria of control tissues. MPM of inflamed murine or human colon tissues revealed a destruction of the mucosal epithelial layer and the crypt architecture together with a strong inflammatory cell infiltration of the lamina propria. MPM of colorectal cancer tissue allowed the visualization of histological characteristics of dysplastic tissue. Depending on the detection of different emission wavelengths, various aspects of tissue morphology could be highlighted (e.g. collagen filaments, infiltrating immune cells). Conclusion: Taken together, the results of this study clearly propose the usability of MPM based on the detection of autofluorescence for the evaluation of gastrointestinal disease. Therefore, the adoption of MPM for gastrointestinal endoscopy seems to be a feasible and attractive aim for the diagnosis of human disease.

Mo1167 Combination Therapy With Metformin and VSL#3 Attenuates Tumor Growth in Western-Style Diet Induced Colitic Cancer Model

Background: Western-style diet (WD) is known to be associated with insulin resistance and colonic inflammation which contributes to carcinogenesis. Biguanide metformin (M) and probiotics VSL#3 (V) can reduce insulin resistance and intestinal inflammation to inhibit tumor growth. We investigated the chemopreventive effect and the mechanism of the agents in WD-induced colitis associated carcinogenesis Methods: Male BALB/c mice were fed a control diet (CD) or WD for 8 weeks and WD groups were divided into groups of no treatment, M alone, V alone and combination therapy (CT). They were exposed to azoxymethane (AOM, 10mg/kg) and followed by 2 % dextran sodium sulfate (DSS) for 7 days. Tumor mass area was measured and tumor nodules were counted in colon of sacrificed mice. Disease activity index (DAI) was checked for 7 days during DSS exposure. Plasma glucose and insulin levels were measured and F4/80, Ki-67, claudin-1 and AMPK expressions were evaluated. Results: Tumor mass area and number of tumor nodules (.4 mm) were significantly decreased in CT group compared with WD group (p,0.01, p=0.016, respectively) and CT group showed low Ki-67 proliferation index (p,0.01). Plasma insulin and glucose levels in treatment groups (M, V, and CT group) were lower than those in WD group. CT group revealed low scores of DAI and decreased F4/80 positive cells accumulation during colitis compared with WD group (p=0.03, p,0.05, respectively). CT group showed maintained epithelial integrity by claudin-1 expression and increased AMPK activation. Conclusions: These results provide that combination therapy with metformin and VSL#3 attenuates tumor growth in WD induced colitic cancer model, which suggest that the treatment strategy could be useful in chemoprevention of colon cancer. The possible mechanisms were AMPK activation and inhibiting macrophage infiltration by maintaining epithelial integrity during colitis. Key word: colitic cancer, chemoprevention, metformin, VSL#3, western-style diet