Detection of colorectal adenomas using a bioactivatable probe specific for matrix metalloproteinase activity

Non-Invasive Compression-Induced Anterior Cruciate Ligament (ACL) Injury and In Vivo Imaging of Protease Activity in Mice

Traumatic joint injuries such as anterior cruciate ligament (ACL) rupture or meniscus tears commonly lead to post-traumatic osteoarthritis (PTOA) within 10-20 years following injury. Understanding the early biological processes initiated by joint injuries (e.g., inflammation, matrix metalloproteinases (MMPs), cathepsin proteases, bone resorption) is crucial for understanding the etiology of PTOA. However, there are few options for in vivo measurement of these biological processes, and the early biological responses may be confounded if invasive surgical techniques or injections are used to initiate OA. In our studies of PTOA, we have used commercially available near-infrared protease activatable probes combined with fluorescence reflectance imaging (FRI) to quantify protease activity in vivo following non-invasive compression-induced ACL injury in mice. This non-invasive ACL injury method closely recapitulates clinically relevant injury conditions and is completely aseptic since it does not involve disrupting the skin or the joint capsule. The combination of these injury and imaging methods allows us to study the time course of protease activity at multiple time points following a traumatic joint injury.

Phthalocyanine-Blue Nanoparticles for the Direct Visualization of Tumors with White Light Illumination

The current standard of care for colon cancer surveillance relies heavily on white light endoscopy (WLE). However, dysplastic lesions that are not visible to the naked eye are often missed when conventional WLE equipment is used. Although dye-based chromoendoscopy shows promise, current dyes cannot delineate tumor tissues from surrounding healthy tissues accurately. The goal of the present study was to screen various phthalocyanine (PC) dye-loaded micelles for their ability to improve the direct visualization of tumor tissues under white light following intravenous administration. Zinc PC (tetra-tert-butyl)-loaded micelles were identified as the optimal formulation. Their accumulation within syngeneic breast tumors led the tumors to turn dark blue in color, making them clearly visible to the naked eye. These micelles were similarly able to turn spontaneous colorectal adenomas in Apc+/Min mice a dark blue color for easy identification and could enable clinicians to more effectively detect and remove colonic polyps.

Fluorescence Molecular Targeting of Colon Cancer to Visualize the Invisible

Colorectal cancer (CRC) is a common cause of cancer and cancer-related death. Surgery is the only curative modality. Fluorescence-enhanced visualization of CRC with targeted fluorescent probes that can delineate boundaries and target tumor-specific biomarkers can increase rates of curative resection. Approaches to enhancing visualization of the tumor-to-normal tissue interface are active areas of investigation. Nonspecific dyes are the most-used approach, but tumor-specific targeting agents are progressing in clinical trials. The present narrative review describes the principles of fluorescence targeting of CRC for diagnosis and fluorescence-guided surgery with molecular biomarkers for preclinical or clinical evaluation.

High Variability in Cellular Proliferation, Gene Expression, and Cytokine Production in the Nonneoplastic Colonic Epithelium of Young Apc+/Min-FCCC Mice

An urgent need exists to identify efficacious therapeutic preventive interventions for individuals who are at high risk of developing colorectal cancer. To maximize the benefits of preventive intervention, it is vital to identify the time interval during which the initiation of a preventive intervention will lead to an optimal outcome. The goal of the present study was to determine if oncogenic events can be detected in the nonneoplastic colonic mucosa of Apc+/Min-FCCC mice prior to formation of the first adenoma, thus defining an earlier point of intervention along the cancer continuum. Tissues taken at three potential points of intervention were characterized: prior to Apc mutation (wild type Apc+/+-FCCC mice); after initiation but prior to colon adenoma formation (tumor-free Apc+/Min-FCCC mice); and after formation of the first colon adenoma (tumor-bearing Apc+/Min-FCCC mice). Experimentation focused on molecular processes that are dysregulated in early colon lesions: 1) cellular proliferation (proliferative index and size of the proliferative zone); 2) cellular stemness (expression of Ascl2, Grem1, Lgr5 and Muc2); 3) EGFR signaling (expression of Ereg); and 4) inflammation (expression of Mmp9, Ptsg2, and Reg4, as well as secretion of 18 cytokines involved in immune activation and response). Interestingly, the nonneoplastic colonic mucosa of wild type, tumor-free Apc+/Min-FCCC , and tumor-bearing Apc+/Min-FCCC mice did not display significant differences in average epithelial cell proliferation (fold change 0.8-1.3, p≥0.11), mucosal gene expression (fold change 0.8-1.4, p≥0.22), or secretion of specific cytokines from colonic mucosa (fold change 0.2-1.5, p≥0.06). However, the level of cytokine secretion was highly variable, with many (22% of wild type, 31% of tumor-free Apc+/Min-FCCC , and 31% of tumor-bearing Apc+/Min-FCCC ) mice categorized as outliers (> 1.5 x interquartile ranges below the first quartile or above the third quartile) due to elevated expression of at least one cytokine. In summary, no differences were observed in proliferation, stemness, and EGFR signaling in the colonic mucosa of wild type vs Apc+/Min-FCCC mice, with low baseline cytokine expression, prior to the formation of the first colon adenoma. The results of this study provide valuable baseline data to inform the design of future cancer prevention studies.

Dysplastic Aberrant Crypt Foci: Biomarkers of Early Colorectal Neoplasia and Response to Preventive Intervention

The discovery of aberrant crypt foci (ACF) more than three decades ago not only enhanced our understanding of how colorectal tumors form, but provided new opportunities to detect lesions prior to adenoma development and intervene in the colorectal carcinogenesis process even earlier. Because not all ACF progress to neoplasia, it is important to stratify these lesions based on the presence of dysplasia and establish early detection methods and interventions that specifically target dysplastic ACF (microadenomas). Significant progress has been made in characterizing the morphology and genetics of dysplastic ACF in both preclinical models and humans. Image-based methods have been established and new techniques that utilize bioactivatable probes and capture histologic abnormalities in vivo are emerging for lesion detection. Successful identification of agents that target dysplastic ACF holds great promise for intervening even earlier in the carcinogenesis process to maximize tumor inhibition. Future preclinical and clinical prevention studies should give significant attention to assessing the utility of dysplastic ACF as the earliest identifiable biomarker of colorectal neoplasia and response to therapy.See all articles in this Special Collection Honoring Paul F. Engstrom, MD, Champion of Cancer Prevention.

Optical imaging with a novel cathepsin-activatable probe for enhanced detection of colorectal cancer

We evaluated a cysteine cathepsin-activatable optical imaging probe (LUM015) with improved kinetics relative to larger macromolecules for detection and characterization of colorectal cancer (CRC), and thereby assessed its potential use in fluorescence-guided colonoscopy. We showed that LUM015 is stable in plasma. In-vitro studies demonstrated selectivity of LUM015 for targeting cathepsins; there was robust increase in emitted fluorescence signal from the cathepsin overexpressing HT-29 CRC cells within 1-5 minutes after incubation with LUM015 compared to the cells incubated with combination of LUM015 and a pan-protease inhibitor (as negative control). Biodistribution, differential accumulation of the probe in the tumor and tumor-to-background fluorescence signal ratio of LUM015 were compared to ProSense680, a commercially available protease-activatable optical imaging probe, over 24 hours after intravenous injection of the probes in nude mice with subcutaneously implanted HT-29 tumors. LUM015 showed distinct kinetics compared to ProSense680 with time to peak signal for subcutaneous tumor-to-colon ratio of 3.3±0.3 (mean ± SD) at 4-8 hours compared to 2.9±0.2 at 24 hours, respectively (n=8 for each group). Near-infrared fluorescence imaging and dual channel colonoscopy of the mice with orthotopic colon tumors showed tumor-to-colon ratio of 3.7±0.2 in HT-29 tumors (n=4), 2.8±0.1 in genetically engineered mice with APC^KOKras^LSL-G12Dp53^flox/flox mutation (n=4), and 4.1±0.1 in mice with APC^LoxP/LoxPMsh2^LoxP/LoxP mutation (n=4) at 6 hours after LUM015 administration. Immunohistochemistry and laser confocal microscopy of the extracted tumors confirmed high expression of cysteine cathepsins in all colon tumor types tested. Optical imaging with cathepsin-activatable LUM015 in multiple models of CRC highlights its potential for increasing the efficacy of CRC screening and therapeutic procedures.

Green SJ, Wang D, Album ZM, Carballo CB, Deng XH, Rodeo SA. Duration of postoperative immobilization affects MMP activity at the healing graft-bone interface: Evaluation in a mouse ACL reconstruction model

Excessive MMP activity may impair tendon-to-bone healing. However, little is known about the effect of joint motion on MMP activity after ACL reconstruction. The aim of this study was to determine the effect of different durations of knee immobilization on MMP activity in a mouse ACL reconstruction model using a fluorescent MMP probe which detects MMP 2, 3, 9, and 13 and near-infra red in vivo imaging. Sixty C57BL male mice underwent ACL reconstruction. Post-operatively, the animals were treated with free cage activity (Group 1), or with the use of an external fixator to restrict knee motion and weight bearing for 5 days (Group 2), 14 days (Group 3), and 28 days (Group 4). At days 3, 7, 16, 23, and 30, five mice underwent IVIS imaging. At days 3, 7, 16, and 30, histological analysis was also performed. Probe signal intensity in the whole limb peaked at day 7, followed by a decrease at day 16, and maintenance up to day 30. There was no significant difference among groups at any time point based on IVIS, but histologic localization of MMP probe signal showed significantly less activity in Group 2 and Group 3 compared to Group 4 in the bone tunnel at day 30. We demonstrated that short-term immobilization led to less MMP activity around the bone tunnel compared with prolonged immobilization. A short period of immobilization after ACL reconstruction might enhance graft-bone interface healing by mitigating excess MMP expression. These findings have implications for post-operative rehabilitation protocols following ACL reconstruction. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:325-334, 2019.

Ex Vivo and In Vivo Noninvasive Imaging of Epidermal Growth Factor Receptor Inhibition on Colon Tumorigenesis Using Activatable Near-Infrared Fluorescent Probes

Background:

Near-infrared fluorescence (NIRF) imaging combined with enzyme-activatable NIRF probes has yielded promising results in cancer detection.

Objective:

To test whether 3-dimensional (3-D) noninvasive in vivo NIRF imaging can detect effects of epidermal growth factor receptor (EGFR) inhibitor on both polypoid and flat tumor load in azoxymethane (AOM)-induced colon tumors or tumors in Apc^Min/+ mice.

Methods:

The AOM-injected KK-HIJ mice received EGFR inhibitor diet or chow diet. These and Apc^Min/+ mice were given cathepsin-activatable probes (ProSense 680) before imaging. In vivo imaging was performed using quantitative tomographic NIRF imaging. Ex vivo imaging and histologic examination were performed. Dual imaging by micro computed tomography (CT) and 3D NIRF imaging was used to verify tumor location.

Results:

Tumor load reduction by EGFR inhibition was detected ex vivo using cathepsin B probes. In vivo imaging revealed intense activation of probes only in large tumors. Dual imaging with microCT and 3D NIRF imaging improved tumor detection in vivo.

Conclusions:

The 3-D NIRF imaging with ProSense 680 can detect and quantify drug effects on colon tumors ex vivo. The NIRF imaging with ProSense 680 probe has limitations as a valid nonendoscopic method for intestinal tumor detection. Combing with other imaging modalities will improve the specificity and sensitivity of intestinal tumor detection in vivo.

In vivo optical imaging of cancer cell function and tumor microenvironment

In vivo optical imaging using fluorescence and bioluminescence is superior to other methods in terms of spatiotemporal resolution and specificity, and represents a new technology for comprehensively studying living organisms in a less invasive way. Nowadays, it is an indispensable technology for studying many aspects of cancer biology, including dynamic invasion and metastasis. In observations of fluorescence or bioluminescence signals in a living body, various problems were caused by optical characteristics such as absorption and scattering and, therefore, observation of deep tissue was difficult. Recent developments in techniques for observation of the deep tissues of living animals overcame this difficulty by improving bioluminescent proteins, fluorescent proteins, and fluorescent dyes, as well as detection technologies such as two‐photon excitation microscopy. In the present review, we introduce these technological developments and in vivo application of bioluminescence and fluorescence imaging, and discuss future perspectives on the use of in vivo optical imaging technology in cancer research.

MicroRNA-30a functions as tumor suppressor and inhibits the proliferation and invasion of prostate cancer cells by down-regulation of SIX1

Increasing reports have demonstrated that aberrant expression of microRNAs (miRNAs) is found in multiple human cancers. Many studies have shown that down-regulated level of miR-30a is in a variety of cancers including prostate cancer (PCa). However, the precise mechanisms of miR-30a in PCa have not been well explored. In this study, we investigated the biological functions and molecular mechanism of miR-30a in PCa cell lines, discussing whether it could be a therapeutic biomarker of PCa in the future. We found that miR-30a is down-regulated in PCa tissues and cell lines. Moreover, the low level of miR-30a was associated with increased expression of SIX1 in PCa tissues and cell lines. Up-regulation of miR-30a significantly inhibited proliferation of PCa cells. In addition, invasion of PCa cells was suppressed by overexpression of miR-30a. However, down-regulation of miR-30a promoted cell growth and invasion of PCa cells. Bioinformatics analysis predicted that the SIX1 was a potential target gene of miR-30a. Next, luciferase reporter assay confirmed that miR-30a could directly target SIX1. Consistent with the effect of miR-30a, down-regulation of SIX1 by siRNA inhibited proliferation and invasion of PCa cells. Overexpression of SIX1 in PCa cells partially reversed the effect of miR-30a mimic. In conclusion, introduction of miR-30a dramatically inhibited proliferation and invasion of PCa cells by down-regulating SIX1 expression, and that down-regulation of SIX1 was essential for inhibition of cell growth and invasion of PCa cells by overexpression of miR-30a.

Imaging Matrix Metalloproteases in Spontaneous Colon Tumors: Validation by Correlation with Histopathology

The use of fluorescent probes in conjunction with white-light colonoscopy is a promising strategy for improving the detection of precancerous colorectal lesions, in particular flat (sessile) lesions that do not protrude into the lumen of the colon. We describe a method for determining the sensitivity and specificity of an enzymatically activated near-infrared probe (MMPSense680) for the detection of colon lesions in a mouse model (APC^+/Min-FCCC) of spontaneous colorectal cancer. Fluorescence intensity correlates directly with the activity of matrix metalloproteinases (MMPs). Overexpression of MMPs is an early event in the development of colorectal lesions. Although the probe employed serves as a reporter of the activity of MMPs, our method can be applied to any fluorescent probe that targets an early molecular event in the development of colorectal tumors.

Imaging Matrix Metalloproteinase Activity Implicated in Breast Cancer Progression

Proteolysis has been cited as an important contributor to cancer initiation and progression. One can take advantage of tumor-associated proteases to selectively deliver imaging agents. Protease-activated imaging systems have been developed using substrates designed for hydrolysis by members of the matrix metalloproteinase (MMP) family. We presently describe approaches by which one can optically image matrix metalloproteinase activity implicated in breast cancer progression, with consideration of selective versus broad protease probes.

Assessment of murine collagen-induced arthritis by longitudinal non-invasive duplexed molecular optical imaging

OBJECTIVE

In the present study we evaluated the use of four commercially available fluorescent probes to monitor disease activity in murine CIA and its suppression during glucocorticoid therapy.

METHODS

Arthritis was induced in male DBA/1 mice by immunization with type II collagen in Complete Freund's Adjuvant, followed by a boost of collagen in PBS. Four fluorescent probes from PerkinElmer in combination [ProSense 750 fluorescent activatable sensor technology (FAST) with Neutrophil Elastase 680 FAST and MMPSense 750 FAST with CatK 680 FAST] were used to monitor disease development from day 5 through to day 40 post-immunization. Fluorescence generated in vivo by the probes was correlated with clinical and histological score and paw measurements.

RESULTS

The fluorescence intensity emitted by each probe was shown to correlate with the conventional measurements of disease. The highest degree of correlation was observed with ProSense 750 FAST in combination with Neutrophil Elastase 680 FAST; these probes were then used to successfully assess CIA suppression during dexamethasone treatment.

CONCLUSION

We have demonstrated that longitudinal non-invasive duplexed optical fluorescence imaging provides a simple assessment of arthritic disease activity within the joints of mice following the induction of CIA and may represent a powerful tool to monitor the efficacy of drug treatments in preclinical studies.

MMP-13 In-Vivo Molecular Imaging Reveals Early Expression in Lung Adenocarcinoma

Introduction

Several matrix metalloproteinases (MMPs) are overexpressed in lung cancer and may serve as potential targets for the development of bioactivable probes for molecular imaging.

Objective

To characterize and monitor the activity of MMPs during the progression of lung adenocarcinoma.

Methods

K-ras^LSL-G12D mice were imaged serially during the development of adenocarcinomas using fluorescence molecular tomography (FMT) and a probe specific for MMP-2, -3, -9 and -13. Lung tumors were identified using FMT and MRI co-registration, and the probe concentration in each tumor was assessed at each time-point. The expression of Mmp2, -3, -9, -13 was quantified by qRT-PCR using RNA isolated from microdissected tumor cells. Immunohistochemical staining of overexpressed MMPs in animals was assessed on human lung tumors.

Results

In mice, 7 adenomas and 5 adenocarcinomas showed an increase in fluorescent signal on successive FMT scans, starting between weeks 4 and 8. qRT-PCR assays revealed significant overexpression of only Mmp-13 in mice lung tumors. In human tumors, a high MMP-13 immunostaining index was found in tumor cells from invasive lesions (24/27), but in none of the non-invasive (0/4) (p=0.001).

Conclusion

MMP-13 is detected in early pulmonary invasive adenocarcinomas and may be a potential target for molecular imaging of lung cancer.

Optical tomography of MMP activity allows a sensitive noninvasive characterization of the invasiveness and angiogenesis of SCC xenografts

For improved tumor staging and therapy control, imaging biomarkers are of great interest allowing a noninvasive characterization of invasiveness. In squamous epithelial skin and cervix lesions, transition to invasive stages is associated with enhanced matrix metalloproteinase (MMP) activity, increased angiogenesis, and worsened prognosis. Thus, we investigated MMP activity as imaging biomarker of invasiveness and the potential of optical tomography in characterizing the angiogenic and invasive behavior of skin squamous cell carcinoma (SCC) xenografts. MMP activity was measured in vivo in HaCaT-ras A-5RT3 tumors at different angiogenic and invasive stages (onset of angiogenesis, intermediate and highly angiogenic, invasive stage) and after 1 week of sunitinib treatment by fluorescence molecular tomography-microcomputed tomography imaging using an activatable probe. Treatment response was additionally assessed morphologically by optical coherence tomography (OCT). In vivo MMP activity significantly differed between the groups, revealing highest levels in the highly angiogenic, invasive tumors that were confirmed by immunohistochemistry. At the onset of angiogenesis with lowest MMP activity, fibroblasts were detected in the MMP-positive areas, whereas macrophages were absent. Accumulation of both cell types occurred in both invasive groups, again to a significantly higher degree at the most invasive and angiogenic stage. Sunitinib treatment significantly reduced the MMP activity and accumulation of fibroblasts and macrophages and blocked tumor invasion that was additionally visualized by OCT. Human cervical SCCs also showed high MMP activity and a similar stromal composition as the HaCaT xenografts, whereas normal tissue was negative. This study strongly suggests MMP activity as imaging biomarker and demonstrates the high sensitivity of optical tomography in determining tumor invasiveness that can morphologically be supported by OCT.

Up-regulation of microRNA-302a inhibited the proliferation and invasion of colorectal cancer cells by regulation of the MAPK and PI3K/Akt signaling pathways

Aberrant expression of microRNA-302a (miR-302a) has been frequently reported in some cancers excluding colorectal cancer (CRC). However, the role of miR-302a in CRC has not been reported. In this paper, we examined the effect of miR-302a overexpression on proliferation and invasion in CRC cells. The mRNA level of miR-302a in CRC cell lines was determined by real-time PCR. The miR-302a mimic was transiently transfected into CRC cells using Lipofectamine™ 2000 reagent. Subsequently, cell proliferation and invasion were assessed by MTT and Transwell assays. Western blot and ELISA assay were used to detect the expressions and secretions of matrix metalloproteinases (MMPs). Moreover, the expressions of epithelial marker, mesenchymal markers and transcription factors were also determined by Western blot. In addition, the effects of miR-302a overexpression on the MAPK and PI3K/Akt signaling pathways were investigated by Western blot. Our results showed that the mRNA level of miR-302a was remarkably decreased in CRC cell lines compared with normal colon epithelium cells. Up-regulation of miR-302a inhibited the proliferation and invasion of CRC cells. The expressions and secretions of MMP-9 and -2 were evidently reduced by increasing miR-302a. Besides, we found a decrease of β-catenin, fibronection, vimentin, Snail, Slug, ZEB1 and ZEB2 expressions and an increase of E-cadherin expression. We also found that miR-302a overexpression might decrease the phosphorylation of Erk1/2 and Akt. Altogether, our results indicated that miR-302a overexpression was shown to inhibit proliferation and invasion of CRC cells by reducing the expressions of related proteins through suppressing the MAPK and PI3K/Akt signaling pathways.

Detection of intestinal cancer by local, topical application of a quenched fluorescence probe for cysteine cathepsins

Early detection of colonic polyps can prevent up to 90% of colorectal cancer deaths. Conventional colonoscopy readily detects the majority of premalignant lesions, which exhibit raised morphology. However, lesions that are flat and depressed are often undetected using this method. Therefore, there is a need for molecular-based contrast agents to improve detection rates over conventional colonoscopy. We evaluated a quenched fluorescent activity-based probe (qABP; BMV109) that targets multiple cysteine cathepsins that are overexpressed in intestinal dysplasia in a genetic model of spontaneous intestinal polyp formation and in a chemically induced model of colorectal carcinoma. We found that the qABP selectively targets cysteine cathepsins, resulting in high sensitivity and specificity for intestinal tumors in mice and humans. Additionally, the qABP can be administered by either intravenous injection or by local delivery to the colon, making it a highly valuable tool for improved detection of colorectal lesions using fluorescence-guided colonoscopy.

Multiparametric classification links tumor microenvironments with tumor cell phenotype

Tumor microenvironment features are established as predictors of tumor cell behavior and fate.

While it has been established that a number of microenvironment components can affect the likelihood of metastasis, the link between microenvironment and tumor cell phenotypes is poorly understood. Here we have examined microenvironment control over two different tumor cell motility phenotypes required for metastasis. By high-resolution multiphoton microscopy of mammary carcinoma in mice, we detected two phenotypes of motile tumor cells, different in locomotion speed. Only slower tumor cells exhibited protrusions with molecular, morphological, and functional characteristics associated with invadopodia. Each region in the primary tumor exhibited either fast- or slow-locomotion. To understand how the tumor microenvironment controls invadopodium formation and tumor cell locomotion, we systematically analyzed components of the microenvironment previously associated with cell invasion and migration. No single microenvironmental property was able to predict the locations of tumor cell phenotypes in the tumor if used in isolation or combined linearly. To solve this, we utilized the support vector machine (SVM) algorithm to classify phenotypes in a nonlinear fashion. This approach identified conditions that promoted either motility phenotype. We then demonstrated that varying one of the conditions may change tumor cell behavior only in a context-dependent manner. In addition, to establish the link between phenotypes and cell fates, we photoconverted and monitored the fate of tumor cells in different microenvironments, finding that only tumor cells in the invadopodium-rich microenvironments degraded extracellular matrix (ECM) and disseminated. The number of invadopodia positively correlated with degradation, while the inhibiting metalloproteases eliminated degradation and lung metastasis, consistent with a direct link among invadopodia, ECM degradation, and metastasis. We have detected and characterized two phenotypes of motile tumor cells in vivo, which occurred in spatially distinct microenvironments of primary tumors. We show how machine-learning analysis can classify heterogeneous microenvironments in vivo to enable prediction of motility phenotypes and tumor cell fate. The ability to predict the locations of tumor cell behavior leading to metastasis in breast cancer models may lead towards understanding the heterogeneity of response to treatment.

A large proportion of cancer deaths are due to metastasis—the spread of cancer from the primary tumor to other parts of the body. Movement of cells may require the formation of protrusions called invadopodia, which degrade extracellular matrix. Although some studies have reported on locomotion in primary tumors, the presence of invadopodia was not tested. Here, we show that single cells from mouse mammary carcinoma can move using a fast- or slow-locomotion mode depending on different levels of cues present in the tumor microenvironment. Using multiphoton microscopy in vivo combined with a machine-learning algorithm we show how manipulation of microenvironmental conditions can induce predictable changes in the number of locomoting cells or switch between the two locomotion modes. We also demonstrate that only the slower moving cells are associated with invadopodia in vivo, and that only tumor cells from regions rich in invadopodia degrade the surrounding extracellular matrix and disseminate. Specific targeting of invadopodia results in inhibition of lung metastasis. This work proposes a systems biology view of how tumor microenvironments regulate tumor progression and presents insight into the heterogeneity of the treatment response. The ability to define and predict conditions under which tumor cells disseminate offers potential therapeutic benefits in regulating tumor progression.

Molecular imaging reveals time course of matrix metalloproteinase activity in acute cutaneous vasculitis in vivo

Matrix metalloproteinases (MMPs) play a critical role in various pathological conditions including cutaneous inflammation. Thus far, serial assessment of MMP activity in ongoing inflammation is hampered due to technical limitations. Here, we present an innovative method for longitudinal detection of MMP activity by in vivo imaging. First, we analysed skin sections from patients suffering from leucocytoclastic vasculitis (LcV) and detected a significant MMP signal via immunofluorescence staining. Then, we mimicked LcV in mice in a well-studied model of immune complex-mediated vasculitis (ICV). This acute inflammatory process was serially visualized in vivo using the fluorescence-labelled MMP tracer Cy5.5-AF443. The deposition of fluorescence-labelled immune complexes and MMP tracer distribution was visualized repeatedly and non-invasively by fluorescence reflectance imaging. In correlation with the presence of MMP-2 and MMP-9 in immunofluorescence stainings, Cy5.5-AF443 accumulated in ICV spots in the skin of C57BL/6 mice. This tracer accumulation could also be observed in mice equipped with a dorsal skinfold chamber, where microscopic observations revealed an increased recruitment of fluorescence-labelled leucocytes during ICV. The specificity of the MMP tracer was supported by (i) analysis of mice deficient in functional β2 -integrins (CD18(-/-) ) and (ii) subsequent MMP immunofluorescence staining. These findings let us conclude that MMP accumulation in the acute phase of ICV depends on β2 -mediated leucocyte recruitment. In summary, we show that MMPs are involved in ICV as determined by Cy5.5-AF443, a new optical marker to longitudinally and non-invasively follow MMP activity in acute skin inflammation in vivo.

In vivo fluorescence reflectance imaging of protease activity in a mouse model of post-traumatic osteoarthritis

OBJECTIVE

Joint injuries initiate a surge of inflammatory cytokines and proteases that contribute to cartilage and subchondral bone degeneration. Detecting these early processes in animal models of post-traumatic osteoarthritis (PTOA) typically involves ex vivo analysis of blood serum or synovial fluid biomarkers, or histological analysis of the joint. In this study, we used in vivo fluorescence reflectance imaging (FRI) to quantify protease, matrix metalloproteinase (MMP), and Cathepsin K activity in mice following anterior cruciate ligament (ACL) rupture. We hypothesized that these processes would be elevated at early time points following joint injury, but would return to control levels at later time points.

DESIGN

Mice were injured via tibial compression overload, and FRI was performed at time points from 1 to 56 days after injury using commercially available activatable fluorescent tracers to quantify protease, MMP, and cathepsin K activity in injured vs uninjured knees. PTOA was assessed at 56 days post-injury using micro-computed tomography and whole-joint histology.

RESULTS

Protease activity, MMP activity, and cathepsin K activity were all significantly increased in injured knees relative to uninjured knees at all time points, peaking at 1-7 days post-injury, then decreasing at later time points while still remaining elevated relative to controls.

CONCLUSIONS

This study establishes FRI as a reliable method for in vivo quantification of early biological processes in a translatable mouse model of PTOA, and provides crucial information about the time course of inflammation and biological activity following joint injury. These data may inform future studies aimed at targeting these early processes to inhibit PTOA development.

Cancer subclonal genetic architecture as a key to personalized medicine

The future of personalized oncological therapy will likely rely on evidence-based medicine to integrate all of the available evidence to delineate the most efficacious treatment option for the patient. To undertake evidence-based medicine through use of targeted therapy regimens, identification of the specific underlying causative mutation(s) driving growth and progression of a patient's tumor is imperative. Although molecular subtyping is important for planning and treatment, intraclonal genetic diversity has been recently highlighted as having significant implications for biopsy-based prognosis. Overall, delineation of the clonal architecture of a patient's cancer and how this will impact on the selection of the most efficacious therapy remain a topic of intense interest.

Matrix metalloproteinase-13 expression in the progression of colorectal adenoma to carcinoma : Matrix metalloproteinase-13 expression in the colorectal adenoma and carcinoma

Most colorectal carcinomas (CRCs) are considered to arise from conventional adenoma based on the concept of the adenoma-carcinoma sequence. Matrix metalloproteinases (MMPs) are known to be overexpressed as normal mucosa progresses to adenomas and carcinomas. There has been little previous investigation about MMP-13 expression in adenoma-carcinoma sequence. In this study, we aimed to investigate the immunohistochemical expression of MMP-13 in colorectal adenoma and CRC specimens using tissue microarray (TMA) technique. A total of 40 cases of CRC associated with adenoma were collected from files of the Pathology laboratory at Mansoura Gastroenterology Center between January 2007 and January 2012. Sections from TMA blocks were prepared and stained for MMP-13. Immunoreactivity to MMP-13 staining was localized to the cytoplasm of mildly, moderately, and severely dysplatic cells of adenomas and CRC tumor cells that were either homogenous or heterogeneous. There was no significant difference in MMP-13 expression between adenomas and CRCs either non-mucinous or mucinous. Adenomas with high MMP-13 expression were significantly associated with moderate to marked degree of inflammatory cellular infiltrate and presence of familial adenomatous polyps. In conclusion, MMP-13 may be a potential biological marker of early tumorigenesis in the adenoma-carcinoma sequence.

The role of matrix metalloproteinases in colorectal cancer

In the United States, colorectal cancer (CRC) is the third leading cause of cancer mortality, with limited treatment options for those with advanced disease. Matrix metalloproteinases (MMPs) are important for maintaining extracellular homeostasis but also play a prominent role in cancer cell invasion and dissemination. Expression levels of MMP-1, -2, -7, -9 and -13 correlate with worse outcomes; MMP-12 expression appears to be protective. Hence, MMPs are attractive therapeutic targets. Previous clinical trials using broad-spectrum MMP inhibitors were disappointing because of off-target toxicity and lack of efficacy. Now, the availability of safer, more selective inhibitors has renewed interest in therapeutic targeting of MMPs.

Overcoming intratumor heterogeneity of polygenic cancer drug resistance with improved biomarker integration

Improvements in technology and resources are helping to advance our understanding of cancer-initiating events as well as factors involved with tumor progression, adaptation, and evasion of therapy. Tumors are well known to contain diverse cell populations and intratumor heterogeneity affords neoplasms with a diverse set of biologic characteristics that can be used to evolve and adapt. Intratumor heterogeneity has emerged as a major hindrance to improving cancer patient care. Polygenic cancer drug resistance necessitates reconsidering drug designs to include polypharmacology in pursuit of novel combinatorial agents having multitarget activity to overcome the diverse and compensatory signaling pathways in which cancer cells use to survive and evade therapy. Advances will require integration of different biomarkers such as genomics and imaging to provide for more adequate elucidation of the spatially varying location, type, and extent of diverse intratumor signaling molecules to provide for a rationale-based personalized cancer medicine strategy.

Morphological distribution of μ chains and cd15 receptors in colorectal polyp and adenocarcinoma specimens

Background

We have recently investigated the localisation of immunoglobulin-producing cells (IPCs) in inflamed intestinal tissue samples from patients with inflammatory bowel disease (IBD), and identified two main patterns of B lymphocyte infiltration: one characterised by the moderate strong stromal localisation of small B1 cell-like IgM+/CD79+/CD20-/CD21-/CD23-/CD5 ± IPCs, and the other by the peri-glandular localisation of IPCs with irregular nuclei that had surface markers specific for a B cell subset (IgM and CD79), but quantitative differences in their λ and κ chains. The same patients were also tested for CD15+ receptors, which were localised on inflammatory cell surfaces or in the crypts of the intestinal epithelium. CD15+ receptor distribution in inflamed tissues was limited to the cell structures. The aim of the study was to analyse variations in IPCs and CD15+ cell morphology or distribution in bowel biopsy specimens taken from patients with pre-malignant polyps or adenocarcinomas.

Methods

IPCs were analysed by means of immunofluorescence using polyclonal goat anti-human μ chains. The pre-malignant polyp specimens were tested for B cell surface phenotype λ and κ chains, CD79, CD20, CD21 and CD23 using an immunoperoxidase method. CD15+ cells were evaluated using the immunoperoxidase method and monoclonal anti-CD15 IgM.

Results

The study involved 14 patients (four with pre-malignant polyps and 10 with colorectal adenocarcinomas). The distribution of μ chains and CD15 markers varied in all of the biopsies, but delineated normal cell structures in the pre-malignant polyp specimens. B cell surface phenotype analysis of μ chain-positive cells identified a subset of CD79+/CD20-/CD21-/CD23- IPCs. The IPCs in certain areas showed the sporadic disintegration of inflammatory cell membranes or the accumulation of fluorescence in individual cells. IPC membrane disintegration was particularly marked in all of the adenocarcinoma samples, in which the CD15 markers also showed epithelial cell involvement. Furthermore, six of the ten adenocarcinoma samples had atypical and reorganised membranes that expressed an excess of both receptors and isolated small portions of tissue within the tumour.

Conclusion

The findings of this preliminary morphological study suggest the presence of membrane disintegration and remodelling mechanisms in the tumours. The newly-formed membranes expressed high concentrations of inflammatory cell receptors that can confer adhesive properties.

Dendritic polyglycerolsulfate near infrared fluorescent (NIRF) dye conjugate for non-invasively monitoring of inflammation in an allergic asthma mouse model

Background

Non-invasive in vivo imaging strategies are of high demand for longitudinal monitoring of inflammation during disease progression. In this study we present an imaging approach using near infrared fluorescence (NIRF) imaging in combination with a polyanionic macromolecular conjugate as a dedicated probe, known to target L- and P-selectin and C3/C5 complement factors.

Methodology/Principal Findings

We investigated the suitability of dendritic polyglycerol sulfates (dPGS), conjugated with a hydrophilic version of the indocyanine green label with 6 sulfonate groups (6S-ICG) to monitor sites of inflammation using an experimental mouse model of allergic asthma. Accumulation of the NIRF-conjugated dPGS (dPGS-NIRF) in the inflamed lungs was analyzed in and ex vivo in comparison with the free NIRF dye using optical imaging. Commercially available smart probes activated by matrix metalloproteinase's (MMP) and cathepsins were used as a comparative control. The fluorescence intensity ratio between lung areas of asthmatic and healthy mice was four times higher for the dPGS in comparison to the free dye in vivo at four hrs post intravenous administration. No significant difference in fluorescence intensity between healthy and asthmatic mice was observed 24 hrs post injection for dPGS-NIRF. At this time point ex-vivo scans of asthmatic mice confirmed that the fluorescence within the lungs was reduced to approximately 30% of the intensity observed at 4 hrs post injection.

Conclusions/Significance

Compared with smart-probes resulting in a high fluorescence level at 24 hrs post injection optical imaging with dPGS-NIRF conjugates is characterized by fast uptake of the probe at inflammatory sites and represents a novel approach to monitor lung inflammation as demonstrated in mice with allergic asthma.

Immunohistochemical expression of matrix metalloproteinase-7 in human colorectal adenomas using specified automated cellular image analysis system: a clinicopathological study

BACKGROUND/AIM

To evaluate the immunohistochemical expression of matrix metalloproteinase-7 (MMP-7) in colorectal adenomas, and to correlate this expression with different clinicopathological parameters.

PATIENTS AND METHODS

The study was retrospectively designed. Thirty three paraffin blocks from patients with colorectal adenoma and 20 samples of non-tumerous colonic tissue taken as control group were included in the study. MMP-7 expression was assessed by immunohistochemistry method. The scoring of immunohistochemical staining was conducted utilizing a specified automated cellular image analysis system (Digimizer).

RESULTS

The frequency of positive immunohistochemical expression of MMP-7 was significantly higher in adenoma than control group (45.45% versus 10%) (P value < 0.001). Strong MMP-7 staining was mainly seen in adenoma cases (30.30%) in comparison with control (0%) the difference is significant ( P < 0.001). The three digital parameters of MMP-7 immunohistochemical expression (Area (A), Number of objects (N), and intensity (I)) were significantly higher in adenoma than control. Mean (A and I) of MMP-7 showed a significant correlation with large sized adenoma (≥ 1cm) ( P < 0.05), also a significant positive correlation of the three digital parameters (A, N, and I) of MMP-7 expression with villous configuration and severe dysplasia in colorectal adenoma had been identified ( P < 0.05).

CONCLUSION

MMP-7 plays an important role in the growth and malignant conversion of colorectal adenomas as it is more likely to be expressed in advanced colorectal adenomatous polyps with large size, severe dysplasia and villous histology. The use of automated cellular image analysis system (Digmizer) to quantify immunohistochemical staining yields more consistent assay results, converts semi-quantitative assay to a truly quantitative assay, and improves assay objectivity and reproducibility.

Chemical biology for understanding matrix metalloproteinase function

The matrix metalloproteinase (MMP) family has long been associated with normal physiological processes such as embryonic implantation, tissue remodeling, organ development, and wound healing, as well as multiple aspects of cancer initiation and progression, osteoarthritis, inflammatory and vascular diseases, and neurodegenerative diseases. The development of chemically designed MMP probes has advanced our understanding of the roles of MMPs in disease in addition to shedding considerable light on the mechanisms of MMP action. The first generation of protease-activated agents has demonstrated proof of principle as well as providing impetus for in vivo applications. One common problem has been a lack of agent stability at nontargeted tissues and organs due to activation by multiple proteases. The present review considers how chemical biology has impacted the progress made in understanding the roles of MMPs in disease and the basic mechanisms of MMP action.

The interconnectedness of cancer cell signaling

The elegance of fundamental and applied research activities have begun to reveal a myriad of spatial and temporal alterations in downstream signaling networks affected by cell surface receptor stimulation including G protein-coupled receptors and receptor tyrosine kinases. Interconnected biochemical pathways serve to integrate and distribute the signaling information throughout the cell by orchestration of complex biochemical circuits consisting of protein interactions and covalent modification processes. It is clear that scientific literature summarizing results from both fundamental and applied scientific research activities has served to provide a broad foundational biologic database that has been instrumental in advancing our continued understanding of underlying cancer biology. This article reflects on historical advances and the role of innovation in the competitive world of grant-sponsored research.