[Investigating the Expression of Cleaved Caspase 3 in Colorectal Adenocarcinoma]

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ABSTRACT

Several techniques to determine apoptotic frequencies in tumors have been described. In this study, we report that biochemical detection of enzymatic caspase-3 activity is a simple and quantitative technique to measure apoptosis in colorectal tumor cells. The relevance of the level of apoptosis in colorectal cancer for the clinical course remains unclear. Therefore, we studied the correlation between caspase-3 activity and prognosis of the disease in relation to different factors known to be involved in apoptosis induction. High caspase-3 activity significantly correlated with a higher risk of recurrence and was preferentially found in tumors of the right side of the colon. No correlation was detected between high caspase-3 activity and altered protein expression of p53, -catenin, or proteins of mismatched repair genes. This indicates that high caspase-3 activity has no evident correlation with the genetic Wnt-signaling or the mismatch repair mutational pathways. The caspase-3 activity significantly correlated with CD57+ tumor infiltrating cells. Therefore, high caspase-3 activity in right-sided tumors might be induced by a specific lymphocytic reaction.

TABLE OF CONTENTS

ABSTRACTII

CHAPTER 1: INTRODUCTION1

Background of the project1

Aims of the project3

Statement of hypothesis3

CHAPTER 2: METHODS4

CHAPTER 3: RESULTS7

Presentation of the Data8

Correct Units10

Quality of Results12

Sufficient Data14

Statistical Analysis17

CHAPTER 5: CONCLUSION23

Proposed future work24

REFERENCES25

APPENDICES31

CHAPTER 1: INTRODUCTION

Background of the project

Cancer of the colon ( and rectum) is the second most common cause of cancer related motility in the western countries. A sequence of events occurs during the development of colorectal cancer. During this, the normal structure of colonic epithelium becomes to grow abnormally and gradually transform into carcinoma tissues. In many cases, the transformation usually develops through the glandular epithelium of the colorectal tissues.

The process of transformation from normal to cancerous tissue is characterized by the accumulation of modified molecular epigenetic, which cause progressive disorders in cell differentiation, cell growth and apoptosis. Under normal circumstances, intestinal epithelial cell homeostasis is maintained by balancing the rates of new cells production and cell dead (apoptosis). In the event of cancer development, the balance between the rate of cells growth and death gradually gets interrupted and thus affecting cell homeostasis. Several studies have been done in the adenoma-carcinoma sequence regarding changes in cell proliferation and it is generally accepted that the severity of dysplasia is directly proportional to the number of proliferating cells. However, changes in the regulation and incidence of apoptosis, which occurs during the development of colorectal caner is not well known.

Apoptosis is an essential biologic process. As well as having a role in controlling cell number during early development, apoptosis is important for the removal of infected or genetically altered cells (Duke et al, 1996, 52). Defects in the apoptotic mechanism are often found in neoplastic growth, which is also the case in colorectal cancer (Evertsson et al, 1999; Gryfe et al, 1997; Tsujitani et al, 1996, 23). Development of colorectal cancer proceeds through a series of genetic alterations that result in the activation of oncogenes and loss of tumor suppressor genes (Gryfe et al 1997; Rafter and Glinghammar, 1998; Ilyas ...