Mechanistic Roles of Rosmarinic acid and Emodin for Gastrointestinal Cancer Treatment = 위장관 종양 치료를 위한 Rosmarinic acid과 Emodin의 기전적 역할

다국어 초록 (Multilingual Abstract)

Gastrointestinal cancers, particularly gastric and colorectal cancers, rank among the
most prevalent malignancies of the digestive track, and remain a major cause of cancer
related deaths worldwide. Conventional therapeutic strategies often fail to achieve long
term remission due to metastasis, recurrence, and cancer stem cell (CSC) survival.
Therefore, designing potent and selective anticancer drugs is essential for improving the
treatment outcomes of gastrointestinal cancers. In this thesis, the therapeutic efficacy of
Echium amoenum extract containing rosmarinic acid (RA) against gastric cancer (GC)
and anthraquinone derivative emodin against colorectal cancer (CRC) is comparatively
examined to elucidate their molecular mechanisms and regulatory pathways.
E. amoenum is a traditional medicinal plant belonging to the Boraginaceae family
that possesses various biological activities, such as anti-inflammatory, antioxidant, and
anticancer effects. In this study, the anticancer activities of the ethyl acetate extract of
E. amoenum (EAEC) and RA, its major component, were investigated in AGS GC cells.
EAEC and RA not only suppressed AGS cell growth by inducing apoptosis through the
caspase-mediated pathway, but also inhibited GC metastasis by regulating the
expression of key epithelial–mesenchymal transition (EMT) biomarkers. Furthermore,
EAEC and RA inhibited phosphorylation of STAT3, ERK1/2, and AKT pathways.
Additionally, the chorioallantoic membrane (CAM) assay confirmed its in vivo
antitumor efficacy.
Emodin, an anthraquinone found in Rheum palmatum and Aloe vera, indicates potent
antioxidant, anti-inflammatory, and anticancer properties. This study explores emodin’s
therapeutic potential against colorectal CSCs, focusing on its ability to modulate cell
cycle progression, induce apoptosis, suppress stemness markers, and inhibit Wnt/β
Catenin signaling, to develop effective CSC-targeted therapies to overcome treatment
resistance and improve CRC clinical outcomes.
EAEC extract was used for the extract-based experiments, while RA and emodin were
applied as commercially purchased, purified single compounds to ensure reproducibility
and mechanistic accuracy.
Overall, these findings suggest that natural phytochemicals, such as RA and emodin,
exhibit comparable abilities to modulate major signaling pathways and suppress tumor
progression in gastrointestinal cancers. EAEC and RA predominantly reduced the
metastatic potential of AGS GC cells by regulating EMT-related proteins, whereas
emodin eliminated the stem-like subpopulation in CRC. Their abilities propose a
promising therapeutic approach to inhibit proliferation, induce apoptosis, and overcome
drug resistance in gastrointestinal cancers.

목차 (Table of Contents)

• List of contents
• Abstract
• List of contents
• List of figures
• List of tables
• Abbreviations
• Chapter Ⅰ. General Introduction 1
• 1.1. Gastrointestinal cancer 2
• 1.2. Objectives of this study 5
• Chapter Ⅱ. Materials and Methods 6
• 2.1. Materials 7
• 2.2. Extraction of E. amoenum 8
• 2.3. HPLC analysis 9
• 2.4. LC-MS analysis 10
• 2.5. Cell culture 10
• 2.6. MTT assay 11
• 2.7. Luminescence assay 12
• 2.8. Tumorsphere formation assay 12
• 2.9. Extreme Limiting Dilution Analysis (ELDA)· 13
• 2.10. Colony formation assay 13
• 2.11. Wound healing assay 13
• 2.12. Invasion assay 14
• 2.13. Cell cycle analysis 14
• 2.14. Apoptosis analysis 15
• 2.15. DAPI assay 15
• 2.16. Intracellular Reactive Oxygen Species (ROS) analysis 16
• 2.17. MitoSOX generation assay 16
• 2.18. Mitochondrial membrane potential (MMP) measurement 16
• 2.19. Chick Embryo Chorioallantoic Membrane (CAM) Assay 17
• 2.20. Network pharmacology 17
• 2.21. Western blot analysis 18
• 2.22. Reverse transcription polymerase chain reaction (RT-PCR) 19
• 2.23. Nuclear-cytoplasmic fractionation assay 20
• 2.24. Statistical analysis 20
• Chapter Ⅲ. Echium amoenum and Rosmarinic Acid Suppress the Growth and Metastasis of Gastric Cancer AGS Cells by Promoting Apoptosis and Inhibiting EMT 21
• 3.1. Background 22
• 3.2. Results 27
• 3.2.1. EAEC inhibits the proliferation and colony formation of AGS cells 27
• 3.2.2. Quantification of EAEC’s Bioactive Components 29
• 3.2.3. RA prevents the proliferation and colony formation of AGS cells 31
• 3.2.4. EAEC and RA induce caspase-mediated apoptosis in AGS cells 33
• 3.2.5. EAEC and RA suppress migration and invasion of AGS cells 36
• 3.2.6. EAEC and RA Modulate the Expression of EMT Regulatory Markers in AGS Cells 38
• 3.2.7. RA inhibits AGS Tumor Growth in the CAM model 41
• 3.3. Discussion 43
• Chapter Ⅳ. Emodin Suppresses the Proliferation and Stemness of Colorectal Cancer Cells via Inhibiting the Wnt//β-Catenin Signaling Pathway 48
• 4.1. Background 49
• 4.2. Results 53
• 4.2.1. Propagation of HCT116- and SW480-derived CSCs through spheroid cell culture · 53
• 4.2.2. Effect of emodin on the viability of colorectal cancer and normal cells 55
• 4.2.3. Emodin induced cell cycle arrest and apoptosis in CRCSCs 59
• 4.2.4. Emodin induced apoptosis-related cellular changes in CRCSCs 61
• 4.2.5. Emodin promotes caspase-independent apoptotic signaling in CRCSCs 64
• 4.2.6. Emodin downregulates stemness markers in CRCSCs· 67
• 4.2.7. Network pharmacology 69
• 4.2.8. Emodin regulates the Wnt/β-Catenin signaling pathway in CRCSCs 71
• 4.3. Discussion 74
• Chapter Ⅴ. Overall conclusions 78
• References 80
• Acknowledgement 94
• Appendix 100