위장관 암세포 종류에 따른 고추장의 항암효과 확인: 분자대사기전 중심으로위장관 암세포 종류에 따른 고추장의 항암효과 확인: 분자대사기전 중심으로 = Anti-cancer effects of Gochujang via distinct molecular and metabolic mechanisms in different GI cancer cells

다국어 초록 (Multilingual Abstract)

Background and Aims
Gastrointestinal (GI) cancers, including gastric, liver, and pancreatic cancers, continue to rise globally and pose significant health concerns due to changes in dietary patterns and lifestyle factors. Numerous studies have shown that various foods and their bioactive compounds exert anti-cancer effects by suppressing tumor cell growth, inducing cell death pathways, and modulating cellular metabolism. Among Korean traditional fermented foods, Gochujang contains diverse functional metabolites and has been reported to provide several health benefits, such as anti-inflammatory, metabolic regulatory, and anti-mutagenic effects. Although the anti-cancer activities of Gochujang have been examined in several cancer cell types, the specific cellular and molecular mechanisms underlying its effects across different GI cancers remain insufficiently understood. Therefore, the present study aimed to clarify the cellular and molecular mechanisms of Gochujang’s anti-cancer effects in GI cancer cells. In particular, we examined whether Gochujang differentially regulates key cancer-related processes—including cell proliferation, cell death pathways, and ROS metabolism—across distinct GI cancer cell types, and compared these mechanisms to better characterize cell type–specific responses.

Materials and Methods
Gochujang extract (GE) was generated from products collected from three different regions in South Korea, including Ganghwa-gun, Sunchang-gun, and Yeongwol-gun. The samples were combined and subjected to extraction using 80% ethanol. To characterize GE, its antioxidant activities were assessed using ABTS and DPPH radical scavenging assays, and its total polyphenol and flavonoid levels were subsequently quantified. The influence of GE on the cell viability of GI cancer cells (gastric cancer cells: AGS and SNU-668; hepatic cancer cells: HepG2 and Hep3B; pancreatic cancer cells: MIA PaCa-2) was assessed across various concentrations and treatment durations. Cell migration was monitored following exposure to GE (AGS, SNU-668, Hep3B and MIA PaCa-2: 0.5-2.5 mg/mL; HepG2: 2.5-10 mg/mL) over a 0-72 hours period, while colony-forming capacity was assessed over a 10-day culture period using GE concentrations (AGS, SNU-668, Hep3B, and MIA PaCa-2: 0.5–2.5 mg/mL; HepG2: 2.5–10 mg/mL). Protein expression changes associated with proliferation, apoptosis and antioxidant pathways were analyzed by western blotting after GE treatment (SNU-668, Hep3B and MIA PaCa-2: 0.5-5 mg/mL). Additionally, ROS production in GI cancer cells was quantified using the DCFDA fluorescence assay.

Results
GE significantly reduced cell viability, migration, and colony-forming capacity in GI cancer cells. It also significantly decreased the expression of key cell cycle–regulating proteins (e.g., p-STAT3, cyclin B1, CDK2, and p-Rb) across all GI cancer cell types, showing dose-dependent reductions in SNU-668 and MIA PaCa-2 cells and significant suppression at higher concentrations in Hep3B cells. In addition, GE significantly decreased the levels of anti-apoptotic proteins (e.g., BCL-2 and BCL-xL) and increased the pro-apoptotic protein Bim across all GI cancer cell lines, with dose-dependent effects in SNU-668 and MIA PaCa-2 cells and marked reductions at higher concentrations in Hep3B cells. Furthermore, GE significantly decreased the levels of antioxidant proteins, including HO-1, SOD1, SOD2, and catalase, across different GI cancer cell types, with dose-dependent reductions in SNU-668 cells, marked decreases in HO-1 and SOD1 in Hep3B cells, and selective reduction of SOD2 in MIA PaCa-2 cells. Consistently, GE significantly increased ROS production in gastric cancer cells (AGS and SNU-668) and hepatic cancer cells (HepG2 and Hep3B) after 24 hours of treatment at 0.5 mg/mL, while ROS levels in pancreatic cancer cells (MIA PaCa-2) remained unchanged.

Conclusion
Gochujang exerts anti-cancer effects across different GI cancer cell types by regulating multiple cellular and molecular mechanisms, including cell proliferation, apoptosis, and ROS metabolism. Importantly, the specific mechanisms vary depending on the cancer cell type, as some GI cancer cell lines show significant changes in ROS metabolism. While others, such as MIA PaCa-2, do not, highlighting GI cancer cell type–dependent differences in Gochujang’s anti-cancer mechanisms.

목차 (Table of Contents)

• Abstract (English) 1
• CHAPTER 1. LITERATURE REVIEW 5
• 1. Gastrointestinal (GI) cancer 6
• 1.1. Factors of GI cancer 11
• 1.1.1. Genetic factors 11
• 1.1.2. Environmental factors 11
• 2. Gochujang 13
• 2.1. Definition of Gochujang 13
• 2.2. Anti-cancer effect of Gochujang 15
• 3. Anti-cancer mechanisms 16
• 3.1. Cancer cell survival mechanisms: Proliferation and Apoptosis 16
• 3.1.1. Proliferation 16
• 3.1.2. Apoptosis 19
• 3.2. ROS metabolism 21
• CHAPTER 2. Gochujang elicits anti-cancer effects via distinct molecular mechanisms across different gastrointestinal cancer cell types 23
• 1. INTRODUCTION 24
• 2. MATERIALS AND METHODS 27
• 3. RESULTS 33
• 4. DISCUSSION 47
• 5. CONCLUSION 51
• REFERENCES 52
• 국문초록 61