Human telomerase is a reverse transcriptase which synthesizes telomeric repeat sequences at the ends of chromosomes. The telomerase enzyme has two essential subunits to be functional which are called telomerase reverse transcriptase (hTERT) and human telomerase RNA (hTR). Telomerase uses its RNA subunit as a template for the addition of hexameric repeats at the ends of chromosomes. The activity of telomerase has been detected in immortal cells but not in most normal somatic cells. Therefore, its activity could serve as diagnostic or prognostic marker in malignancies. Telomeres are heterochromatic DNA sequences bound by a number of telomere binding proteins in order to maintain the stability of chromosomes. Protection of telomere 1(POT1) is a single stranded telomere binding protein which is thought to have significant role in the recruitment of telomerase to telomeres. The objective of the current study to investigate telomerase activity and gene expression of hTERT and hPOT1 in human colorectal cancer tissues. The activity of telomerase was examined in colorectal tumors and normal adjacent specimens by and improved telomeric repeat amplification protocol (TRAP)-Silver Staining Assay. The expression levels of hTERT and hPOT1 genes was analysed by qPCR. The results showed that colorectal cancer tumors showed significantly high telomerase activity whereas normal adjacent tissues were found to be telomerase negative. Among clinicopathological parameters / the stage, histological type, distant metastasis and lymph node metastasis status of tumors were found to show significant differences in terms of telomerase activity. Moreover, the expression of human telomerase reverse transcriptase (hTERT) was found to be overexpressed in tumor tissues compared to normal adjacent tissues. Likewise, colorectal tumors expressed high level of hPOT1 compared to normal tissues. Both the expression of hTERT and hPOT1 correlated with telomerase activity. It can be concluded from the results of the current study that high telomerase activity and overexpression of hTERT and hPOT1, may indicate that they could serve as diagnostic or prognostic indicators in colorectal cancer.

Ecological momentary assessment provides a unique way of studying quality of life factors of colorectal cancer patients. It has yet to be used to study the behavioral expression of distress or depression by colorectal cancer patients. The current study utilized the Electronically Activated Recorder (EAR) technology to capture the daily activities and conversations of forty-eight adults with colorectal cancer. The study had two purposes: 1) to test the feasibility of the EAR with colorectal cancer patients; 2) to examine separate (self-report and behavioral) indicators of physical functioning, coping, and social support for their relationship to depression. Study participants wore the EAR, a portable digital recorder, for two consecutive days as the EAR recorded 30 seconds every 12.5 minutes. The EAR digital data were transcribed and analyzed for behavioral and linguistic indicators of physical functioning, coping, and social support. The acoustic data were analyzed using the standardized coding system Social Environment Coding of Sound Inventory (SECSI) and the Linguistic Inquiry and Word Count (LIWC2007) computer program. The results provided preliminary evidence that the EAR operated as a feasible and non-disruptive tool for gathering naturalistic data about colorectal patients’ lives. The EAR data revealed information about both the colorectal patients’ internal emotional world as well as their external world which was characterized by solitary acts of daily living. Study subjects were more likely to accept and receive tangible support from others than directly discuss their cancer with others. Analysis of language found that personal disclosure to others was associated with coping through emotional support while causation words (e.g., because, effect, hence) were significantly related with self-report cognitive scales. Furthermore, the study found that first-person singular pronouns were associated not only with depression, but with appraisal of social support. Lastly, a predictive model was tested to see whether self-reported tangible and emotional support and behavioral coding of emotional support each contributed uniquely to the prediction of depression. Only self-reported tangible support was found to significantly predict depression. / text

Advances in optical imaging have provided methods for visualizing molecular expression in tumors in vivo, allowing the opportunity to study the complexity of the tumor microenvironment. The development of fluorescent contrast agents targeted to molecules expressed in cancer cells is critical for in vivo imaging of the tumors. Contrast agents emitting in the near infrared (NIR) allow for an increased depth of penetration in tissue due to decreased absorption and scattering. There is also significantly less autofluorescence from tissue in the NIR. Quantum dots are nanoscopic particles of semiconductors whose fluorescent emission wavelength is tunable by the size of the particle with desirable fluorescent qualities such as a wide range of excitation wavelengths, a narrow emission band, high quantum efficiency, high photostablility, and they can be produced to emit throughout the NIR imaging window. It has been shown that vascular endothelial growth factor receptor 2 (VEGFR2) is upregulated in many cancers, including colorectal, as it is important in tumor angiogenesis and is considered a predictor for clinical outcome and, in some instances, is used for targeted therapy with anti-angiogenic drugs. For these reasons, quantum dots bioconjugated to VEGFR2 antibodies have the potential to provide contrast between normal tissue and cancer, as well as a mechanism for evaluating the molecular changes associated with cancer in vivo. In this dissertation, we present on the design of two contrast agents using quantum dots targeted to VEGFR2 for use in the molecular imaging of colon cancer, both ex vivo and in vivo. First, as a preliminary ex vivo investigation into their efficacy, Qdot655® (655nm emission) were bioconjugated to anti-VEGFR2 antibodies through streptavidin/biotin linking. The resulting QD655-VEGFR2 contrast agent was used to label colon adenoma in vivo and imaged ex vivo with significant increase in contrast between diseased and undiseased tissue, allowing for fluorescence based visualization of the VEGFR2 expressing diseased areas of the colon with high sensitivity and specificity. Then, QD655-VEGFR2 was used in a longitudinal in vivo study to investigate ability to correlate fluorescence signal to tumor development over time using optical coherence tomography and laser induced fluorescence spectroscopy (OCT/LIF) dual-modality imaging. The contrast agent was able to target VGEFR2 expressing diseased areas of colon; however, challenges in fully flushing the unbound contrast agent from the colon before imaging arise when moving from ex vivo imaging to in vivo image. Lastly, lead sulfide (PbS) quantum dots were made by colloidal synthesis to emit at a 940 nm (QD940) and conjugated to anti-VEGFR2 primary antibodies through streptavidin/biotin linking. The resulting QD940-VEGFR2 contrast agent was then used to label cells in vitro. The QD940-VEGFR2 molecules were able to positively label VEGFR2 expressing cells and did not label VEGFR2 negative cells. Very low photoluminescence and large amounts of aggregation after conjugation of the quantum dot to streptavidin was detected. Improvements to the quantum dot stability through synthesis, capping and conjugation techniques must be made for this contrast agent to be effective as a contrast agent for cancer imaging.

Background: Clinical and epidemiologic studies have investigated the effects of diet, physical activity, and inflammation on the risk of colorectal adenoma occurrence and recurrence. Inflammation has been proposed as a mechanism of action for the development of colorectal adenoma and cancer. Research indicates that fruit phenolic exposure may attenuate the inflammatory response and some data suggest that berries are effective in mitigating this process. Inflammatory cytokines such as interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor alpha (TNF-α) are of particular interest due to their role in adenoma development. Epidemiological investigations have studied the association between bioactive fruit phenolic compounds and colorectal neoplasia; however, epidemiological data for the association between consumption of berries, which contain high concentrations of these compounds, and colorectal adenoma recurrence are limited. In addition to a potential role of phenolics in reducing inflammation, physical activity has also been proposed as a mitigator of this process. Numerous studies have investigated the association between physical activity and colorectal neoplasia, yet data on sedentary behavior and colorectal adenoma recurrence are limited. This dissertation was designed to further elucidate the role of fruit phenolics and sedentary behavior on colorectal adenoma recurrence and to specifically highlight the potential role of black raspberries in mitigating the postprandial inflammatory response among overweight and obese individuals. Methods: Ten overweight or obese males (BMI>25 kg/m²), ages 55-72, participated in an open-label, randomized, 14-day, pilot crossover study. Subjects consumed a high- fat, high- calorie (HFHC) meal, with (Group 1) or without (Group 2) a 5 day regimen of 45 g of black raspberry powder in the form of a slurry. The study included a two-day washout period before Group 1 and Group 2 were crossed over. The two-day washout period was based on a pharmacokinetic study conducted with black raspberry powder (1); peak plasma concentrations of ellagic acid and anthocyanin metabolites peaked at 1 to 2 hours following consumption of 45 grams of black raspberry powder and by 12 hours, plasma concentrations of these metabolites were almost fully washed out, with plasma concentrations returning to near baseline levels. Blood samples were obtained prior to consumption of the HFHC breakfast and at 1, 2, 4, 8, and 12 hours afterwards, during two 14-hour clinic visits. The primary study outcomes were changes in areas under the curves (AUCs) of serum biomarkers of TNF-α, CRP, and IL-6. A secondary pooled analysis was conducted among participants from two randomized, double blind, placebo-controlled Phase III clinical trials to investigate the association between berry consumption and colorectal adenoma recurrence, and the association between sedentary behavior and colorectal adenoma recurrence. Analyses included 2,502 subjects who had completed the baseline Arizona Food Frequency Questionnaire to ascertain berry consumption history in the past year and 1,730 men and women who had completed the baseline Arizona Activity Frequency Questionnaire to ascertain sedentary behavior. All subjects had a follow-up colonoscopy during the trial. Logistic regression modeling was employed to estimate the effect of sedentary behavior or berry consumption on colorectal adenoma recurrence. Results: The mean AUC of serum IL-6 was significantly lower (p=0.03) with black raspberry (BRB) feeding (45.5±36.3 pg/mL; mean±SD), compared to high fat, high calorie meal alone (56.7±50.0 pg/mL). No statistically significant differences were observed in the mean AUC of serum TNF-α or CRP. In the pooled analysis, no significant associations were observed between berry consumption and adenoma recurrence in the pooled population or when stratified by sex. In the evaluation of association between sedentary behavior and adenoma recurrence, subjects in the second, third, and fourth quartiles of sedentary behavior experienced higher odds of adenoma recurrence; however, the difference was only statistically significant for the third quartile. Sex-stratified analyses revealed that in men, sedentary activity was statistically significantly associated with 45% higher odds of adenoma recurrence. Compared to the lowest quartile of sedentary activity, the ORs (95% CIs) for the second, third, and fourth quartiles among men were 1.31 (0.93, 1.84), 1.47 (1.04, 2.09), and 1.45 (1.02, 2.06) respectively (P trend=0.03). In contrast, no association with sedentary activity was observed in women. Conclusion: Polyphenol exposure in the form of a black raspberry slurry significantly decreased post-prandial IL-6 in a clinical trial among ten older overweight and obese men. These findings suggest short-term attenuation of an inflammatory maker may not translate to decreased adenoma recurrence, however, long term randomized clinical trials with black raspberries are needed to evaluate this further. However, in an epidemiological analysis, consumption of up to 1 cup per week of whole berries was not associated with lower odds for adenoma recurrence among a pooled population of participants in the Wheat Bran Fiber and Ursodeoxycholic Acid Phase III clinical trials. While the epidemiological results indicated that berry consumption are not associated with the development of early colorectal neoplasia, the effects on later stages of carcinogenesis are unknown. Higher levels of berry consumption may be required in order to reach a cancer inhibitory effect. Finally, results of the physical activity study suggest that sedentary behavior is associated with a higher risk of adenoma recurrence among men, providing evidence of detrimental effects of a sedentary lifestyle early in the carcinogenesis pathway. Efforts to further evaluate these findings in other cohorts or in an intervention trial should be considered.

Colorectal cancer (CRC) is a leading cause of cancer-related deaths around the world. The identification and description of many modifiable and non-modifiable risk factors to CRC has spurred the development of prevention and early detection protocols and recommendations to help reduce CRC incidence and mortality. Measures to manage CRC include diagnostic screenings and lifestyle changes. As rates of screening increase, prevention counseling rates among primary care providers (PCPs) remain low. Barriers to nutrition prevention reported by PCPs are inconsistent across the literature which has led to confusion about the reason for poor nutrition prevention efforts among PCPs. This practice inquiry (PI) addressed the identified practice gap using the Plan-Do-Study-Act (PDSA) quality improvement (QI) model. In the "Plan" phase (Chapter 2), a systematic review of the research literature determined existing nutrition recommendations for CRCs and barriers to implementation by PCPs. Development of several nutrition recommendations for fiber, vitamin D, alcohol, red and processed meats intakes, and dietary patterns were outlined for PCP use in practice. Barriers to nutrition prevention implementation were identified as time, reimbursement, knowledge, and health literacy. To augment findings from the literature, a provider survey was completed (Chapters 3-4). Barriers identified by the participants (n=47) include lack of time, education materials, nutrition knowledge, low health literacy, and lack of patient interest. These findings indicate that several changes are needed to improve the use of CRC prevention guidelines, including additional education and education materials, changes in office policy and additional research to create and analyze the interventions recommended to improve existing nutrition prevention counseling for CRC.

Research has identified a linear relationship between saturated fat intake and colon cancer, and has demonstrated that high fat diets enhance tumorigenesis through elevation of secondary bile acids such as deoxycholic acid (DCA). We and others have shown that DCA can manipulate cell adhesion by decreasing expression of E-cadherin and increasing expression of beta-catenin. We have also shown that DCA significantly reduces EphB2 expression, which regulates cell positioning and segregation. Importantly, vitamin D can reinstate membranous E-cadherin/beta-catenin interactions and increase E-cadherin expression. In the present study, we sought to analyze the effects of DCA and vitamin D (cholecalciferol) treatment on EphB2 in colorectal cancer cells. Pre-treatment with cholecalciferol restored EphB2 expression in a dose-dependent manner, even with combined DCA treatment. This observation may be EGFR-dependent, suggesting that cholecalciferol may antagonize the effects of DCA. Taken together, these results suggest that cholecalciferol may represent an adjuvant therapy for colorectal cancer patients.

Kolorektale Karzinome sind durch ein spezifisches Muster chromosomaler Aberrationen charakterisiert, die im Verlauf der Tumorprogression akkumulieren. Obwohl die meisten Tumoren Sequenzgewinne oder Amplifikationen von Chromosom 13q aufweisen, sind die Zielgene dieser Aberration nach wie vor unbekannt. Um potentielle Onkogene bzw. therapeutische Zielgene auf Chromosom 13q zu identifizieren, wurde eine hochauflösende Analyse dieser Region durchgeführt. Dazu wurden 25 primäre Kolonkarzinome (UICC-II/III) und 15 kolorektale Zelllinien mittels Array-CGH untersucht. Zusätzlich wurden die Genexpressionsprofile dieser Tumoren und Zelllinien mittels Whole-Genome-Mikroarrays bestimmt. 67 Gene wiesen sowohl eine vermehrte Kopie-Anzahl als auch ein erhöhtes Expressionsniveau auf. Die Expressionsmuster dieser Gene wurden dann in 25 Kolonkarzinom-Zelllinien mittels Real-Time-PCR validiert, wobei 44 der 67 Gene eine deutliche Überexpression auch in den Zelllinien zeigten. Das Ausschalten von 13 dieser 44 Gene in der Kolonkarzinom-Zelllinie SW480 führte zu einer Reduktion der Zellviabilität von 20-60%. Diese 13 Gene könnten somit potentielle Onkogene oder mögliche therapeutische Zielgene darstellen. In Folgeexperimenten versuchen wir daher, die der Viabilitätsreduktion zugrundeliegenden Signalwege zu entschlüsseln.

Tumorerkrankungen stellen in der westlichen Welt eines der wichtigsten Gesundheitsprobleme dar. Das kolorektale Karzinom ist dabei die dritthäufigste Tumorneuerkrankung. Bei fortgeschrittenem Krankheitsverlauf wird zumeist eine kombinierte Radiochemotherapie durchgeführt, bei der zusätzlich zur Bestrahlung Zytostatika wie 5-Fluoruracil oder Oxaliplatin verabreicht werden. Da die eingesetzten Zytostatika nicht ausschließlich gegen Tumorzellen wirken, führt der Einsatz dieser oft zu massiven Nebenwirkungen wie Magen- und Darmproblemen, Myelosuppression und Haarausfall. Neue Therapieansätze versuchen daher Ziele in die Behandlung mit aufzunehmen die stärker karzinomspezifisch sind, wie z.B. verschiedenen Rezeptortyrosinkinasen. Viele Rezeptortyrosinkinasen und deren Liganden liegen im Tumor und umliegenden Gewebe oft dereguliert vor und spielen eine wichtige Rolle bei der Regulierung des Tumorwachstums, der Tumorangiogenese und der Metastasenbildung. In dieser Arbeit konnte für die drei kolorektalen Karzinomzelllinien DLD-1, SW837 und Caco 2 gezeigt werden, dass die gleichzeitige Inhibition des Insulin-like Growth Factor-I Receptor (IGF-IR) und des Epidermal Growth Factor Receptor (EGFR) mit den Tyrosinkinaseinhibitoren AEW-541 (IGF-IR-Inhibitor) und Erlotinib (EGFR-Inhibitor) in vitro zu einem deutlich verstärkten Therapieeffekt der 5-Fluoruracil-basierten Radiochemotherapie führt. Für Xenografttumore der Zelllinie SW837 konnte dieser Effekt auch in vivo bestätigt werden. Mit Hilfe der Co Immunpräzipitation und eines Proximity Ligation Assays konnten in den Kolonkarzinomzelllinien SW480 und DLD-1 Hybridrezeptoren zwischen dem EGFR und dem IGF-IR nachgewiesen werden. Zusätzlich konnte gezeigt werden, dass eine Ligandenstimulation der Rezeptoren zu einer vermehrten EGFR/IGF-IR-Hybridrezeptorbildung führt. Weitere Analysen zeigten, dass für die induzierte Heterodimerisierung beide Liganden notwendig sind und beide Rezeptoren funktionsfähig sein müssen. Mit Hilfe des Proximity Ligation Assays konnten IGF-IR/EGFR-Hybridrezeptoren auch in humanen Rektumtumoren nachgewiesen werden. Im letzten Teil der Arbeit wurde die Bedeutung des Platelet-derived Growth Factor Receptor β (PDGFR-β) in kolorektalen Karzinomzellen untersucht. In SW480- und DLD-1-Zellen führte die Inhibition des PDGFR-β mit Hilfe von spezifischer siRNA zu einer, über den PI3K-Signalweg vermittelten, moderat verminderten Proliferationsrate. Die Verwendung des PDGFR-β-Inhibitors Ki11502 führte in den Zelllinien zu einem starken Rückgang in der Proliferationsrate und zu Veränderungen im Zellzyklus der Zellen. Diese wurden durch eine verminderte Cyclin-B1-Expression hervorgerufen. Weitere Analysen zeigten, dass der Inhibitor Ki11502 neben dem PDGFR-β auch den Rezeptor cKIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) und die Zellmembran-assoziierte zytoplasmatische Tyrosinkinase SRC (v-src sarcoma (Schmidt-Ruppin A-2) viral oncogene homolog) inhibiert.

1. INTRODUCTION Colon and rectum cancers (CRC) accounted for about 1 million new cases in 2002 (9.4 % of the world total) with about 529,000 deaths and 2.8 million alive with CRC diagnosed within 5 years of diagnosis [Parkin DM et al, 2005]. Recent estimates indicate that in 2004 CRC among the most common incident form of cancer in the Europe was in the second position with more than 380,000 new cases (13.2% of total). CRC was also one of two most common causes of cancer deaths in Europe (203,700 per year) [Boyle P et al, 2005]. A favourable pattern in CRC mortality for both genders was observed in most of western European countries from the 1990s onwards, but CRC mortality rates were still in the upward direction in some eastern European countries [Fernandez E et al, 2005]. For patients diagnosed with CRC during the early 1990s, the EUROCARE study showed that differences in stage at diagnosis were a key explanation for differences in survival between western European countries, and differences in therapy contributed to survival differences between eastern and western European countries [Gatta G et al, 2000]. The number of new cases of CRC in Lithuania is increasing every year. According to the data of Lithuanian Cancer Registry, there were diagnosed 1442 new colorectal cancer cases and 973 deaths in 2004 in Lithuania [The main results of cancer control in Lithuania. Transitional report 2004. Lithuanian Cancer Registry]. CRC is in the third position according new cancer... [to full text]

Introduction: Despite the public and policy attention on ensuring access to health care for all Canadians, research continues to identify inequities in access to cancer care services. The objectives of this thesis are to define inequity in access to colorectal cancer (CRC), as well as to measure inequity in access to radiotherapy and end-of-life care. Methods: This study examined income-, geography-, sex-, and age-related inequity in access to CRC services along the continuum of care, using the Horizontal Inequity Index. Specifically, we measured and compared inequity in access CRC services in Nova Scotia using linked administrative databases. Results: We have identified that age- and geography-related inequity in access to radiotherapy and end-of-life care are the most consistent for CRC patients in Nova Scotia. Discussion: The clear distinction between inequity and inequality in this study provides indication to policy makers that the variations in access, may be of social concern.