• Journal of Ginseng Research
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• v.48 no.1
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• pp.31-39
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• 2024

Background: Ginsenoside Rg3, a primary bioactive component of red ginseng, has anti-cancer effects. However, the effects of Rg3-enriched ginseng extract (Rg3RGE) on apoptosis and autophagy in breast cancer have not yet been investigated. In the present study, we explored the anti-tumor effects of Rg3RGE on breast cancer cells stimulated CoCl₂, a mimetic of the chronic hypoxic response, and determined the operative mechanisms of action. Methods: The inhibitory mechanisms of Rg3RGE on breast cancer cells, such as apoptosis, autophagy and ROS levels, were detected both in vitro. To determine the anti-cancer effects of Rg3RGE in vivo, the cancer xenograft model was used. Results: Rg3RGE suppressed CoCl₂-induced spheroid formation and cell viability in 3D culture of breast cancer cells. Rg3RGE promoted apoptosis by increasing cleaved caspase 3 and cleaved PARP and decreasing Bcl2 under the hypoxia mimetic conditions. Further, we identified that Rg3RGE promoted apoptosis by inhibiting lysosomal degradation of autophagosome contents in CoCl₂-induced autophagy. We further identified that Rg3RGE-induced apoptotic cell death and autophagy inhibition was mediated by increased intracellular ROS levels. Similarly, in the in vivo xenograft model, Rg3RGE induced apoptosis and inhibited cell proliferation and autophagy. Conclusion: Rg3RGE-stimulated ROS production promotes apoptosis and inhibits protective autophagy under hypoxic conditions. Autophagosome accumulation is critical to the apoptotic effects of Rg3RGE. The in vivo findings also demonstrate that Rg3RGE inhibits breast cancer cell growth, suggesting that Rg3RGE has potential as potential as a putative breast cancer therapeutic.

• Journal of Life Science
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• v.34 no.1
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• pp.37-47
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• 2024

FUN14 domain-containing protein 1 (FUNDC1), an outer mitochondrial membrane protein, contributes to removal of damaged mitochondria through mitophagy. In this study, to elucidate the role of the FUNDC1 in the amyloid beta peptide (A_β)-induced neuropathy, changes in the degree of mitochondrial dysfunction and cell injury caused by A_β treatment were examined in the HT-22 neuronal cells in which the FUNDC1 expression was transiently silenced or overexpressed. We found that A_β treatment causes a time-dependent decrease of the FUNDC1 expression. In the A_β-treated cells, there were a drop in MTT reduction ability, depletion of cellular ATP, disruption of mitochondrial membrane potential, stimulation of cellular ROS production, and increased mitochondrial Ca²⁺ load. Activation of caspase-3 and induction of apoptotic cell death were also observed. Transient silencing of the FUNDC1 expression by transfection with the FUNDC1 small interfering RNA per se caused mitochondrial dysfunction and apoptotic cell death like the effect of A_β treatment. Conversely, in cells in which the FUNDC1 was transiently overexpressed by FUNDC1-Myc transfection, overexpression itself had no effect on the mitochondrial functional integrity and cell survival but showed a significant prevention effect against mitochondrial and cell injury caused by A_β treatment. Overall, these results suggest that the FUNDC1 is importantly involved in the A_β-induced mitochondrial dysfunction and cell injury in the HT-22 neuronal cells.

• IMMUNE NETWORK
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• v.22 no.4
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• pp.34.1-34.19
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• 2022

Osteoarthritis (OA) is the most common form of arthritis associated with ageing. Vitamin D has diverse biological effect on bone and cartilage, and observational studies have suggested it potential benefit in OA progression and inflammation process. However, the effect of vitamin D on OA is still contradictory. Here, we investigated the therapeutic potential of vitamin D in OA. Six-week-old male Wistar rats were injected with monosodium iodoacetate (MIA) to induce OA. Pain severity, cartilage destruction, and inflammation were measured in MIA-induced OA rats. Autophagy activity and mitochondrial function were also measured. Vitamin-D (1,25(OH)₂D3) and celecoxib were used to treat MIA-induced OA rats and OA chondrocytes. Oral supplementation of vitamin D resulted in significant attenuations in OA pain, inflammation, and cartilage destruction. Interestingly, the expressions of MMP-13, IL-1β, and MCP-1 in synovial tissues were remarkably attenuated by vitamin D treatment, suggesting its potential to attenuate synovitis in OA. Vitamin D treatment in OA chondrocytes resulted in autophagy induction in human OA chondrocytes and increased expression of TFEB, but not LC3B, caspase-1 and -3, in inflamed synovium. Vitamin D and celecoxib showed a synergistic effect on antinociceptive and chondroprotective properties in vivo. Vitamin D showed the chondroprotective and antinociceptive property in OA rats. Autophagy induction by vitamin D treatment may be a promising treatment strategy in OA patients especially presenting vitamin D deficiency. Autophagy promoting strategy may attenuate OA progression through protecting cells from damage and inflammatory cell death.

• Herbal Formula Science
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• v.31 no.4
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• pp.231-243
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• 2023

Objectives : Jasminum officinale L. var. grandiflorum is used as a traditional or folk remedy in China to treat arthritis, hepatitis, duodenitis, conjunctivitis, gastritis, and diarrhea. In this study, we aimed to study the hepatocyte protective activity and molecular mechanism of Jasminum officinale L. var. grandiflorum aqueous extract (JGW) using HepG2 hepatocyte cell lines. Methods : HepG2 cells were pretreated with diverse concentrations of JGW, and then the cells were exposed to tert-butyl hydroperoxide (tBHP) for inducing oxidative stress. Hydrogen peroxide (H₂O₂) production, glutathione (GSH) concentration, mitochondrial membrane potential (MMP) and cell viability were measured to investigate hepato-protective effects of JGW. Phosphorylation of AMP-activated protein kinases (AMPK), acetyl coenzyme A carboxylase (ACC) and effects of compound C on cell viability were examined to observe the role of AMPK on JGW-mediated cytoprotection. Results : Pretreatment with JGW (10-300 ㎍/mL) significantly suppressed cytotoxicity induced by tBHP in a concentration dependent manner and reduced the expression of cleaved PARP and cleaved caspase-3 proteins related to apoptosis in HepG2 cells. In addition, pretreatment with JGW significantly prevented the increase in H₂O₂ production, GSH depletion, and lower MMP induced by tBHP. Treatment with JGW (30 minutes of incubation and concentrations of 100 and 300 ㎍/mL) increased the phosphorylation of AMPK and ACC and treatment with compound C, a chemical inhibitor of AMPK, inhibited the cytoprotective effect of JGW. Conclusions : Our results demonstrated that JGW may protect hepatocytes from oxidative stress via activation of AMPK.

• Journal of Nutrition and Health
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• v.57 no.1
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• pp.43-52
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• 2024

Purpose: Cancer is the leading cause of death in Koreans, with breast cancer being the most common among women. Breast cancer readily metastasizes, and the existing treatment processes impose a significant burden on patients. This study examined whether pomegranate-derived exosome-like nanovesicles (PNVs) have anti-cancer effects by inhibiting cell infiltration and metastasis while increasing apoptosis on breast cancer MDA-MB-231 cells. Methods: Initially, exosome-like nanovesicles were isolated from pomegranate using ultracentrifugation. Subsequently, the size range of these nanovesicles was confirmed using nanoparticle tracking analysis. The ability of breast cancer MDA-MB-231 cells to internalize these natural nanovesicles was assessed with flourescence microscope. The anti-cancer effects of the PNVs were confirmed by applying various concentrations of PNVs (10, 50, 100 ㎍/mL) to MDA-MB-231 cells and systematically assessing their impact on cell viability and migration. Results: The round shape of the lipid bilayer in the PNVs was confirmed, providing crucial insights into their structural properties. We demonstrate that PNVs-associated DiD dye can be efficiently internalized by the MDA-MB-231 cells. The data showed that the PNVs inhibited cell viability, invasion rates, and migration in MDA-MB-231 cells. In addition, PNVs were absorbed into the MDA-MB-231 cells, leading to an increased expression of apoptosis proteins, such as cleaved caspase-3 and phosphorus-JNK, in a concentration-dependent manner. Furthermore, a reduction in cell infiltration and decreased expression of the transition markers MMP-2 and MMP-9 proteins were observed. Conclusion: For the first time, this study suggests that PNVs may be useful in the prevention or treatment of breast cancer by inhibiting the infiltration and metastasis of MDA-MB-231 cells and inducing apoptosis.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.329-340
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• 2024

Mangiferin is a kind of natural xanthone glycosides and is known to have various pharmacological activities. However, since the beneficial efficacy of this compound has not been reported in retinal pigment epithelial (RPE) cells, this study aimed to evaluate whether mangiferin could protect human RPE ARPE-19 cells from oxidative injury mimicked by hydrogen peroxide (H₂O₂). The results showed that mangiferin attenuated H₂O₂-induced cell viability reduction and DNA damage, while inhibiting reactive oxygen species (ROS) production and preserving diminished glutathione (GSH). Mangiferin also antagonized H₂O₂-induced inhibition of the expression and activity of antioxidant enzymes such as manganese superoxide dismutase and GSH peroxidase, which was associated with inhibition of mitochondrial ROS production. In addition, mangiferin protected ARPE-19 cells from H₂O₂-induced apoptosis by increasing the Bcl-2/Bax ratio, decreasing caspase-3 activation, and blocking poly(ADP-ribose) polymerase cleavage. Moreover, mangiferin suppressed the release of cytochrome c into the cytosol, which was achieved by interfering with mitochondrial membrane disruption. Furthermore, mangiferin increased the expression and activity of heme oxygenase-1 (HO-1) and nuclear factor-erythroid-2 related factor 2 (Nrf2). However, the inhibition of ROS production, cytoprotective and anti-apoptotic effects of mangiferin were significantly attenuated by the HO-1 inhibitor, indicating that mangiferin promoted Nrf2-mediated HO-1 activity to prevent ARPE-19 cells from oxidative injury. The results of this study suggest that mangiferin, as an Nrf2 activator, has potent ROS scavenging activity and may have the potential to protect oxidative stress-mediated ocular diseases.

• Journal of Life Science
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• v.26 no.3
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• pp.376-386
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• 2016

Apoptosis induction has been proposed as an efficient mechanism by which malignant tumor cells can be removed following chemotherapy. The intrinsic mitochondria-dependent apoptotic pathway is frequently implicated in chemotherapy-induced tumor cell apoptosis. Since DNA-damaging agent (DDA)-induced apoptosis is mainly regulated by the tumor suppressor protein p53, and since more than half of clinical cancers possess inactive p53 mutants, microtubule-damaging agents (MDAs), of which apoptotic effect is mainly exerted via p53-independent routes, can be promising choice for cancer chemotherapy. Recently, we found that the apoptotic signaling pathway induced by MDAs (nocodazole, 17α-estradiol, or 2-methoxyestradiol) commonly proceeded through mitotic spindle defect-mediated prometaphase arrest, prolonged Cdk1 activation, and subsequent phosphorylation of Bcl-2, Mcl-1, and Bim in human acute leukemia Jurkat T cells. These microtubule damage-mediated alterations could render the cellular context susceptible to the onset of mitochondria-dependent apoptosis by triggering Bak activation, Δψm loss, and resultant caspase cascade activation. In contrast, when the MDA-induced Bak activation was inhibited by overexpression of anti-apoptotic Bcl-2 family proteins (Bcl-2 or Bcl-xL), the cells in prometaphase arrest failed to induce apoptosis, and instead underwent mitotic slippage and endoreduplication cycle, leading to formation of populations with 8N and 16N DNA content. These data indicate that cellular apoptogenic mechanism is critical for preventing polyploid formation following MDA treatment. Since the formation of polyploid cells, which are genetically unstable, may cause acquisition of therapy resistance and disease relapse, there is a growing interest in developing new combination chemotherapies to prevent polyploidization in tumors after MDA treatment.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.181-185
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• 2001

The naturally occurring chemical indole-3-carbinol (13C), found in vegetables of the Brassica genus, is a promising anticancer agent that was shown previ- ously to induce a Gl cell cycle arrest of human breast cancer cell lines, independent of estrogen receptor signaling. The anticancer activity of 13C and the possible mechanisms of its action were explored in a human hepatocellular carcinoma cell line, HepG2. Treatment of HepG2 cells with 13C suppressed the growth of the cells. The growth sup- pression caused by 13C ($IC_{50}$/: 444$\mu$M) was found to be partially due to its ability to stop the cell cycle in HepG2 cells. Western blot analysis for the Gl phase artiest demonstrated that the expression-levels of cyclin-dependent kinase (Cdk4, Cdk6) and cyclic D were reduced strongly after treatment of Hep72 cells with 13C (4007M) for 24- 72 hrs. Furthermore, I3C selectively abolished the expression of Cdk6 in a dose- and time-dependent manner, and accordingly, inhibited the phosphorylation of retinoblastoma. Interestingly, after the HepG2 cells reached their max- imal growth arrest, the level of the p21, a well-known Cdk inhibitor, increased significantly. Therefore, it could be considered that the Gl arrest of HepG2 cells treated with 13C was due to the indirect inhibition of Cdk4/6 activities by p21 Western blot analysis for G2/M phase arrest of demonstrated the levels of Cdc2 and cyclin Bl werer reduced dramatically after the treatment of HepG2 cells with 13C ($40\mu$M) for 24-72 hrs. flow cytometry of propidium iodide-stained HepG2 cells revealed that 13C induces a Gl (53%,72hr incubation) and G2 (25%,24hr incubation) cell cycle arrest. Thus, our observations have uncovered a previously undefined antiproliferative pathway for r3C that implicates Cdk4/6 and Cdc2 as a target for cell cycle control in human HepG2 cells. However, the 13C-medi- ated cell cycle arrest and repression of Cdk4/6 production did not affect the apoptotic induction of HepG2 cell.

• Tuberculosis and Respiratory Diseases
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• v.60 no.3
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• pp.304-313
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• 2006

Background : Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes the oxidative degradation of heme to form biliverdin, carbon monoxide (CO), and free iron. The current evidence has indicated a critical role of HO-1 in cytoprotection and also in other, more diverse biological functions. It is known that the high expression of HO-1 occurs in various tumors, and that HO-1 has an important role in rapid tumor growth because of its antioxidative and antiapoptotic effects. Therefore, the role of HO-1 was analyzed in human lung cancer cell lines, and especially in the A549 cell line. Material and Methods : Human lung cancer cell lines, i.e., A549, NCI-H23, NCI-H157 and NCI-H460, were used for this study. The expression of HO-1 in the untreated state was defined by Western blotting. ZnPP, which is the specific HO inhibitor we used, and the viability of cells were tested for by conducting MTT assaysy. The HO enzymatic activity, as determined via the bilirubin level, was also indirectly measured. Moreover, the generation of intracellular hydrogen peroxide (H2O2) was monitored fluorimetrically with using a scopoletin-horse radish peroxidase (HRP) assay and 2',7'-dichlorofluorescein diacetate (DCFH-DA). We have also transfected small HO-1 interfering RNA (siRNA) into A549 cells, and the apoptotic effects were evaluated by flow cytometric analysis and Western blotting. Results : The A549 cells had a greater expression of HO-1 than the other cell lines, whereas ZnPP significantly decreased the viability of the A549 cells more than the viability of the other lung cancer cells in a dose-dependant fashion. Consistent with the viability, the HO enzymatic activity also was decreased. Moreover, intracellular H2O2 generation via ZnPP was induced in a dose-dependent manner. Apoptotic events were, then induced in the HO-1 siRNA transfected A549 cells. Conclusion : HO-1 provides new important insights into the possible molecular mechanism of the antitumor therapy in lung cancer.

• Tuberculosis and Respiratory Diseases
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• v.65 no.6
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• pp.476-486
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• 2008

Background: TRAIL (TNF-related apoptosis inducing ligand) is a newly identified member of the TNF gene family which appears to have tumor-selective cytotoxicity due to the distinct decoy receptor system. TRAIL has direct access to caspase machinery and induces apoptosis regardless of p53 phenotype. Therefore, TRAIL has a therapeutic potential in lung cancer which frequently harbors p53 mutation in more than 50% of cases. However, it was shown that TRAIL also could activates $NF-{\kappa}B$ in some cell lines which might inhibit TRAIL-induced apoptosis. This study was designed to investigate whether TRAIL can activate $NF-{\kappa}B$ in lung cancer cell lines relatively resistant to TRAIL-induced apoptosis and inhibition of $NF-{\kappa}B$ activation using proteasome inhibitor MG132 which blocks $I{\kappa}B{\alpha}$ degradation can sensitize lung cancer cells to TRAIL-induced apoptosis. Methods: A549 (wt p53) and NCI-H1299 (null p53) lung cancer cells were used and cell viability test was done by MTT assay. Apoptosis was confirmed with Annexin V assay followed by FACS analysis. To study $NF-{\kappa}B$-dependent transcriptional activation, a luciferase reporter gene assay was used after making A549 and NCI-H1299 cells stably transfected with IgG ${\kappa}-NF-{\kappa}B$ luciferase construct. To investigate DNA binding of $NF-{\kappa}B$ activated by TRAIL, electromobility shift assay was used and supershift assay was done using anti-p65 antibody. Western blot was done for the study of $I{\kappa}B{\alpha}$ degradation. Results: A549 and NCI-H1299 cells were relatively resistant to TRAIL-induced apoptosis showing only 20~30% cell death even at the concentration 100 ng/ml, but MG132 ($3{\mu}M$) pre-treatment 1 hour prior to TRAIL addition greatly increased cell death more than 80%. Luciferase assay showed TRAIL-induced $NF-{\kappa}B$ transcriptional activity in both cell lines. Electromobility shift assay demonstrated DNA binding complex of $NF-{\kappa}B$ activated by TRAIL and supershift with p65 antibody. $I{\kappa}B{\alpha}$ degradation was proven by western blot. MG132 completely blocked both TRAIL-induced $NF-{\kappa}B$ dependent luciferase activity and DNA binding of $NF-{\kappa}B$. Conclusion: This results suggest that inhibition of $NF-{\kappa}B$ can be a potentially useful strategy to enhance TRAIL-induced tumor cell killing in lung cancer.