• The Korean Journal of Physiology and Pharmacology
• /
• v.14 no.5
• /
• pp.331-336
• /
• 2010

In rapidly growing tumors, hypoxia commonly develops due to the imbalance between $O_2$ consumption and supply. Hypoxia Inducible Factor (HIF)-$1{\alpha}$ is a transcription factor responsible for tumor growth and angiogenesis in the hypoxic microenvironment; thus, its inhibition is regarded as a promising strategy for cancer therapy. Given that CamKII or PARP inhibitors are emerging anticancer agents, we investigated if they have the potential to be developed as new HIF-$1{\alpha}$-targeting drugs. When treating various cancer cells with the inhibitors, we found that a CamKII inhibitor, KN-62, effectively suppressed HIF-$1{\alpha}$ specifically in hepatoma cells. To examine the effect of KN-62 on HIF-$1{\alpha}$-driven gene expression, we analyzed the EPO-enhancer reporter activity and mRNA levels of HIF-$1{\alpha}$ downstream genes, such as EPO, LOX and CA9. Both the reporter activity and the mRNA expression were repressed by KN-62. We also found that KN-62 suppressed HIF-$1{\alpha}$ by impairing synthesis of HIF-$1{\alpha}$ protein. Based on these results, we propose that KN-62 is a candidate as a HIF-$1{\alpha}$-targeting anticancer agent.

• Archives of Pharmacal Research
• /
• v.28 no.1
• /
• pp.68-72
• /
• 2005

Pseudolaric acid B is a major compound found in the bark of Pseudolarix kaempferi Gordon. In our study, pseudolaric acid B inhibited growth of human melanoma cells, A375-S2 in a time and dose-dependent manner. A375-S2 cells treated with pseudolaric acid B showed typical characteristics of apoptosis including morphologic changes, DNA fragmentation, sub-diploid peak in flow cytometry, cleavage of poly-ADP ribose polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD). P53 protein expression was upregulated while cells were arrested at the $G_2/M$ phase of the cell cycle. There was a decrease in the expression of anti-apoptotic Bcl-2 and Bcl-xL proteins, whereas pro-apoptotic Bax was increased. The two classical caspase substrates, PARP and ICAD, were both decreased in a time-dependent manner, indicating the activation of downstream caspases.

• BMB Reports
• /
• v.56 no.8
• /
• pp.451-456
• /
• 2023

Deubiquitinases (DUBs) are an essential component of the ubiquitin-proteasome system (UPS). They trim ubiquitin from substrate proteins, thereby preventing them from degradation, and modulate different cellular processes. Ubiquitin-specific protease 14 (USP14) is a DUB that has mainly been studied for its role in tumorigenesis in several cancers. In the present study, we found that the protein levels of USP14 were remarkably higher in gastric cancer tissues than in the adjacent normal tissues. We also demonstrated that the inhibition of USP14 activity using IU1 (an USP14 inhibitor) or the inhibition of USP14 expression using USP14-specific siRNA markedly reduced the viability of gastric cancer cells and suppressed their migratory and invasive abilities. The reduction in gastric cancer cell proliferation due to the inhibition of USP14 activity was a result of the increase in the degree of apoptosis, as evidenced by the increased expression levels of cleaved caspase-3 and cleaved PARP. Furthermore, an experiment using the USP14 inhibitor IU1 revealed that the inhibition of USP14 activity suppressed 5-fluorouracil (5-FU) resistance in GC cells. Collectively, these findings indicate that USP14 plays critical roles in gastric cancer progression and suggest its potential to serve as a novel therapeutic target for gastric cancer treatment.

• International Journal of Oncology
• /
• v.56 no.1
• /
• pp.368-378
• /
• 2020

Meridianin C is a marine natural product with anticancer activity. Several meridianin C derivatives (compounds 7a-j) were recently synthesized, and their inhibitory effects on pro-viral integration site for Moloney murine leukemia virus (PIM) kinases, as well as their antiproliferative effects on human leukemia cells, were reported. However, the anti-leukemic effects and mechanisms of action of meridianin C and its derivatives remain largely unknown. The aim of the present study was to investigate the effects of meridianin C and its derivatives on MV4-11 human acute myeloid leukemia cell growth. The parent compound meridianin C did not markedly affect the viability and survival of MV4-11 cells. By contrast, MV4-11 cell viability and survival were reduced by meridianin C derivatives, with compound 7a achieving the most prominent reduction. Compound 7a notably inhibited the expression and activity of PIM kinases, as evidenced by reduced B-cell lymphoma-2 (Bcl-2)-associated death promoter phosphorylation at Ser112. However, meridianin C also suppressed PIM kinase expression and activity, and the pan-PIM kinase inhibitor AZD1208 only slightly suppressed the survival of MV4-11 cells. Thus, the anti-survival effect of compound 7a on MV4-11 cells was unrelated to PIM kinase inhibition. Moreover, compound 7a induced apoptosis, caspase-9 and -3 activation and poly(ADP-ribose) polymerase (PARP) cleavage, but did not affect death receptor (DR)-4 or DR-5 expression in MV4-11 cells. Compound 7a also induced the generation of cleaved Bcl-2, and the downregulation of myeloid cell leukemia (Mcl)-1 and X-linked inhibitor of apoptosis (XIAP) in MV4-11 cells. Furthermore, compound 7a increased eukaryotic initiation factor (eIF)-2α phosphorylation and decreased S6 phosphorylation, whereas GRP-78 expression was unaffected. Importantly, treatment with a pan-caspase inhibitor (z-VAD-fmk) significantly attenuated compound 7a-induced apoptosis, caspase-9 and -3 activation, PARP cleavage, generation of cleaved Bcl-2 and downregulation of Mcl-1 and XIAP in MV4-11 cells. Collectively, these findings demonstrated the strong anti-survival and pro-apoptotic effects of compound 7a on MV4-11 cells through regulation of caspase-9 and -3, Bcl-2, Mcl-1, XIAP, eIF-2α and S6 molecules.

• Archives of Pharmacal Research
• /
• v.27 no.8
• /
• pp.834-839
• /
• 2004

In human neuroblastoma SK-N-BE(2) cells undergoing apoptotic death induced by ginsenos-ide Rh2, a dammarane glycoside that was isolated from Panax ginseng C. A. Meyer, caspase-1 and caspase-3 were activated. The expression of Bax was increased in the cells treated with ginsenoside Rh2, whereas Bcl-2 expression was not altered. Treatment with caspase-1 inhibi-tor, Ac-YVAD-CMK, or caspase-3 inhibitor, Z-DEVD-FMK, partially inhibited ginsenoside Rh2-induced cell death but almost suppressed the cleavage of the 116 kDa PARP into a 85 kDa fragment. When the levels of p53 were examined in this process, p53 accumulated rapidly in the cells treated early with ginsenoside Rh2. These results suggest that activation of caspase-1 and -3 and the up-regulation of Bax are required in order for apoptotic death of SK-N-BE(2) cells to be induced by ginsenoside Rh2, and p53 plays an important role in the pathways to promote apoptosis.

• Korean Journal of Clinical Laboratory Science
• /
• v.56 no.3
• /
• pp.198-206
• /
• 2024

EZH2 is a methyltransferase that is a critical target for lymphoma treatment. However, it is not yet widely used in clinical settings. PROteolysis TArgeting Chimeras (PROTACs) represent a novel therapeutic strategy aimed at eliminating proteins that have been a challenging target using conventional small molecules. In our previous research, we compared the small molecules-based EZH2 inhibitor used in clinical settings with a PROTAC-based EZH2 degrader. We found that the PROTAC-based degrader was significantly more effective. Building on this, we further investigated the effects of combining the PROTAC-based EZH2 degrader (dEZH2) with a METTL3 inhibitor, both of which have demonstrated effectiveness in inhibiting cell proliferation and inducing apoptosis in Burkitt's lymphoma. Using the CCK-8 assay, we found that both drugs, alone and in combination, significantly inhibited Daudi and Ramos cell growth in a dose-dependent manner. The combined treatment markedly suppressed cell proliferation and induced apoptosis, as confirmed by Annexin V/PI staining. Our results revealed G2/M phase arrest with a significant decrease in the G0/G1 phase by flow cytometry. Our study also showed increased levels of cleaved PARP, cleaved caspase-3, tumor protein p53 (TP53), and PUMA using the western blot technique, indicating enhanced p53-dependent apoptosis. Our findings suggest that the combination therapy of dEZH2 and iMETTL3 could be a promising approach in the treatment of Burkitt's lymphoma.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.4
• /
• pp.542-550
• /
• 2018

Heat shock protein 90 (Hsp90) is treated as a molecular therapeutic target for the prevention and treatment of cancer. Geldanamycin (GA) was the first identified natural Hsp90 inhibitor, but hepatotoxicity has limited its clinical application. Nevertheless, a new GA analog (WK-88-1) with the non-benzoquinone skeleton, obtained from genetically engineered Streptomyces hygroscopicus, was found to have anticancer activity against two human breast cancer cell lines. WK-88-1 produced concentration-dependent inhibition of cell proliferation, cell cycle arrest, and apoptosis in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 cell lines. Detailed analysis showed that WK-88-1 downregulated some key cell cycle molecules (CDK1 and cyclin B1) and lead to $G_2/M$ cell cycle arrest. Further studies also showed that WK-88-1 could induce human breast cancer cell apoptosis by downregulating Hsp90 client proteins (Akt, p-Akt, IKK, c-Raf, and Bcl-2), decreasing the ATP level, increasing reactive oxygen species production, and lowering the mitochondrial membrane potential. Meanwhile, we discovered that WK-88-1 significantly decreased the levels of Her-2 and $ER-{\alpha}$ in MCF-7 cells but not in MDA-MB-231 cells. In addition, WK-88-1 significantly increased caspase-3, -8, and -9 activities and the cleavage of PARP in a concentration-dependent manner (with the exception of caspase-3 and PARP in MCF-7 cells). Taken together, our preliminary results suggest that WK-88-1 has the potential to play a role in breast cancer therapy.

• Archives of Pharmacal Research
• /
• v.28 no.1
• /
• pp.87-92
• /
• 2005

The cyclin-dependent kinase inhibitor$p27^{kip1}$(p27) has been implicated in the regulation of cell cycle and apoptosis. Recently, we have demonstrated that ceramide induces apoptotic cell death associated with increase in the level of p27 in HL-60 cells. In the present study, we showed that overexpression of p27 increases ceramide-induced apoptotic cell death in HL-60 cells. Furthermore, overexpression of p27 accelerated DNA fragmentation, PARP cleavage and cytochrome c release induced by ceramide. In addition, ceramide induced Sax expression independent of p27. These findings indicate that enhanced effect on apoptosis by p27 is associated with mitochondrial signaling which involves cytochrome c release.

• Biomolecules & Therapeutics
• /
• v.17 no.1
• /
• pp.17-24
• /
• 2009

Histone deacetylase (HDAC) inhibitors are a promising class of anticancer agents that inhibit cancer cell growth in vitro and in vivo. Previous report has shown that apicidin inhibited SK-OV-3 cells proliferation and down-regulation of cyclin B1 and CDK1, and up-regulation of $p21^{WAF1}$ and p27. However, the mechanism of apicidin-mediated apoptotic cell death is not clearly understood. For this study, we investigated the mechanism of apoptotic pathway induced by apicidin in human ovarian cancer cell. We found that SK-OV-3 cells treated with apicidin caused an increase in the percentage of cells in the G2/M phase, which preceded apoptosis characterized by the appearance of cells with sub-G1 population. To further investigate the mechanism of apoptosis induction by apicidin, we measured TUNEL assay, poly-ADP ribose polymerase (PARP) cleavage, and caspase activity in SK-OV-3 cells treated with apicidin for 48 h. Apicidin significantly enhanced apoptosis as measured by TUNEL positive apoptotic cells, PARP cleavage, and increased Bax/Bcl-2 ratio. Induction of apoptosis was confirmed by the release of cytochrome c to cytosol. Our data suggest that apicidin-induced apoptosis in SK-OV-3 cells was accompanied by caspase-3 activation and the increase in Bax/Bcl-2 ratio. These data suggest that apicidin may be effective in the treatment of ovarian cancer through activation of intrinsic apoptotic pathway.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.11
• /
• pp.4519-4525
• /
• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.