• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4341-4346
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• 2012

Purpose: The aim of this study was to cast light on initiating molecular events associated with the development of premalignant oral lesions induced by tobacco and/or areca nut. Method: Immunohistochemical analyses of cell cycle regulatory proteins (LIMD1, RBSP3, p16, RB, phosphorylated RB, p53), EGFR and SH3GL2 (EGFR associated protein) were performed with inflammatory/ulcerative epithelium and adjacent hyperplastic/mild dysplastic lesions. Results: No change in expression of the proteins was seen in inflammatory epithelium. Reduced nuclear expression of LIMD1 was evident in ulcerative epithelium. In hyperplastic lesions, reduced expression of RBSP3, p16, SH3GL2 and overexpression of p-RB and EGFR were apparent. Reduced nuclear expression of p53 was observed in mild dysplastic lesions. Conclusion: Our data suggest that inactivation of LIMD1 in ulcerative epithelium might predispose the tissues to alterations of other cell cycle regulatory and EGFR signaling proteins needed for the development of premalignant oral lesions.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.340-349
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• 2023

Mad2B (Mad2L2), the human homolog of the yeast Rev7 protein, is a regulatory subunit of DNA polymerase ζ that shares sequence similarity with the mitotic checkpoint protein Mad2A. Previous studies on Mad2B have concluded that it is a mitotic checkpoint protein that functions by inhibiting the anaphase-promoting complex/cyclosome (APC/C). Here, we demonstrate that Mad2B is activated in response to cisplatin-induced DNA damage. Mad2B co-localizes at nuclear foci with DNA damage markers, such as proliferating cell nuclear antigen and gamma histone H2AX (γ-H2AX), following cisplatin-induced DNA damage. However, unlike Mad2A, the binding of Mad2B to Cdc20 does not inhibit the activity of APC/C in vitro. In contrast to Mad2A, Mad2B does not localize to kinetochores or binds to Cdc20 in spindle assembly checkpoint-activated cells. Loss of the Mad2B protein leads to damaged nuclei following cisplatin-induced DNA damage. Mad2B/Rev7 depletion causes the accumulation of damaged nuclei, thereby accelerating apoptosis in human cancer cells in response to cisplatin-induced DNA damage. Therefore, our results suggest that Mad2B may be a critical modulator of DNA damage response.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 추계학술대회
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• pp.160-160
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• 2003

Antioxidative potentials of estrogen and genistein were compared by measuring the degree of protection against plasmid DNA strand breakage induced by peroxyl free radicals using the DNA strand scission assay with pBR322 DNA. Genistein decreased DNA strand breakage by AAPH radical treatment at the all of three concentrations tested (0.5, 1.0, 1.5 $\mu\textrm{g}$/$m\ell$) with the range of 89.5% to 99.6%.(omitted)

• Reproductive and Developmental Biology
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• 제33권4호
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• pp.243-248
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• 2009

To examine the differential expression of proteins during the cycling (70~80% confluences) and G0/G1 (full confluences) phases in porcine fetal fibroblast cells, we used a global proteomics approach by 2-D gel electrophoresis (2-DE) and MALDI-TOF-MS. Cycling cell were harvested at approximately 70% to 80% confluent state while cells in G0/G1 phase were recovered after maintenance of a confluent state for 48 hr. Cellular proteins with isoelectric points ranging between 3.0~10.0, were analyzed by 2-DE with 2 replicates of each sample. A total of approximately 700 spots were detected by 2.D gels stained with Coomassie brilliant blue. On comparing the cell samples obtained from the cycling and G0/G1 phases, a total of 13 spots were identified as differentially expressed proteins, of which 8 spots were up-regulated in the cycling cell and 5 were up-regulated in the G0/G1 phase. Differentially expressed proteins included K3 keratin, similar to serine protease 23 precursor, protein disulfide-isomerase A3, microsomal protease ER-60, alpha-actinin-2, and heat-shock protein 90 beta. The identified proteins were grouped on the basis of their basic functions such as molecular binding, catabolic, cell growth, and transcription regulatory proteins. Our results show expression profiles of key proteins in porcine fetal fibroblast cells during different cell cycle status.

• Radiation Oncology Journal
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• 제21권4호
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• pp.306-314
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• 2003

목적: K562 세포의 방사선에 의한 세포 사망은 mitotic catastrophe 현상이 위주로 나타나지만 herbimycin A (HMA)에 의하여 apoptosis 반응이 촉진되는 반면 genisteln에 의하여 두 가지 형태의 세포사망이 모두 억제된다. 본 연구에서는 HMA와 genistein에 의한 K562세포의 방사선 유도 세포주기 조절 변화와 세포 사망 양상의 연관성을 조사하였다. 대상 및 방법: 지수증식기의 KS62 세포에 6 MV 선형가속기(Clinac 1,m C, Varian)를 이용하여 200~300 cGy/min의 선량률로 10 Gy를 균일하게 조사하였다. HMA와 genistein은 각각 250 nM와 25$\mu$M농도로 방사선 조사 후 즉시 투여하였다. 실험에서는 세포주기, 오절인자의 발현 및 활성, 노화 및 분화정도 등에 있어서의 시간에 따른 변화를 조사하였다. 결과: 방사선 단독조사에서 KS62세포는 G2기의 정체를 보였으나 정상적인 053을 가지는 세포와는 달리 지속적인 세포주기의 정체를 보이지 않았다. G2정체가 유지되는 동안 cyclin Bl의 점진적인 증가를 관찰할 수 있었으며, 이는 염색체의 복제가 완료되지 않은 상태에서 M기로 진행하여 미성숙한 염색체 응축과 mitotic catastrophe 현상이 나타나는 것과 일치한다. 방사선 조사와 함께 HMA를 투여한 경우에는 G2정체가 빠르게 해소되었으며 동시에 Gl기에서 세포가 정체되는 양상을 보였다. 세포주기 조절인자 cdc2 kinase 활성 증가와 cyclln I와 A 발현 및 CDK2 활성의 감소 등의 현상으로 설명되며, 이는 apoptosis의 증가와 연관성을 갖는다. 반면 genistein의 경우에는 cyclin Bl과 떨cfsc 발현 및 cdc2활성이 모두 감소하는 등 G2정체를 계속 유지하였다. 이와 함께 방사선에 의한 노화와 megakaryocyte로의 분화도 지속되는 것을 관찰할 수 있었다. 결론: HMA와 genistein에 의한 KS62세포의 방사선 유도 세포사망의 변화는 세포주기 조절과 밀접하게 연관되어 있음을 확인하였다. 이는 다양한 방사선 유도 세포사망의 기전을 이해하는 데 독창적인 모델을 제공하며, 방사선을 이용한 암 치료법의 개발에 새로운 표적을 제공할 수 있을 것이다.

• 동의생리병리학회지
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• 제22권4호
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• pp.821-828
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• 2008

Onchungeum, a herbal formula, which has been used for treatment of anemia due to bleeding, discharging blood and skin disease. In the present study, it was examined the effects of extract of Onchungeum (OCE) on the growth of human hepatocarcinoma cell lines Hep3B (p53 null type) and HepG2 (p53 wild type) in order to investigate the anti-proliferative mechanism by OCE. Treatment of Hep3B and HepG2 cells to OCE resulted in the growth inhibition in a dose-dependent manner, however Hep3B cell line exhibited a relatively strong anti-proliferative activity to OEC. Flow cytometric analysis revealed that OCE treatment in Hep3B cells caused G1 phase arrest of the cell cycle, which was associated with various morphological changes in a dose-dependent fashion. RT-PCR and immunoblotting data revealed that treatment of OCE caused the down-regulation of cyclin D1 expression, however the levels of cyclin E expression were not changed by OCE. The G1 arrest of the cell cycle was also associated with the induction of Cdk inhibitor p27 by OCE. Because the p53 gene is null in Hep3B cells, it is most likely that the induction of p21 is mediated through a p53-independent pathway. Moreover, p27 detected in anti-Cdk4 and anti-Cdk2 immunoprecipitates from the OCE-treated cells, suggesting that OCE-induced p27 protein blocks Cdk kinase activities by directing binding to the cyclin/Cdk complexes. Furthermore, OCE treatment potently suppresses the phosphorylation of retinoblastoma proteins and the levels of the transcription factor E2F-1 expression. Taken together, these results indicated that the growth inhibitory effect of OCE in Hep3B hepatoma cells was associated with the induction of G1 arrest of the cell cycle through regulation of several major growth regulatory gene products.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1615-1623
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• 2021

Picropodophyllotoxin (PPT), an epimer of podophyllotoxin, is derived from the roots of Podophyllum hexandrum and exerts various biological effects, including anti-proliferation activity. However, the effect of PPT on colorectal cancer cells and the associated cellular mechanisms have not been studied. In the present study, we explored the anticancer activity of PPT and its underlying mechanisms in HCT116 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to monitor cell viability. Flow cytometry was used to evaluate cell cycle distribution, the induction of apoptosis, the level of reactive oxygen species (ROS), assess the mitochondrial membrane potential (Δψm), and multi-caspase activity. Western blot assays were performed to detect the expression of cell cycle regulatory proteins, apoptosis-related proteins, and p38 MAPK (mitogen-activated protein kinase). We found that PPT induced apoptosis, cell cycle arrest at the G1 phase, and ROS in the HCT116 cell line. In addition, PPT enhanced the phosphorylation of p38 MAPK, which regulates apoptosis and PPT-induced apoptosis. The phosphorylation of p38 MAPK was inhibited by an antioxidant agent (N-acetyl-L-cysteine, NAC) and a p38 inhibitor (SB203580). PPT induced depolarization of the mitochondrial inner membrane and caspase-dependent apoptosis, which was attenuated by exposure to Z-VAD-FMK. Overall, these data indicate that PPT induced G1 arrest and apoptosis via ROS generation and activation of the p38 MAPK signaling pathway.

• Biomolecules & Therapeutics
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• 제23권3호
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• pp.225-232
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• 2015

We identified a novel Akt signaling mechanism that mediates fucoidan-induced suppression of human colon cancer cell (HT29) proliferation and anticancer effects. Fucoidan treatment significantly inhibited growth, induced G1-phase-associated upregulation of p21WAF1 expression, and suppressed cyclin and cyclin-dependent kinase expression in HT29 colon cancer cells. Additionally, fucoidan treatment activated the Akt signaling pathway, which was inhibited by treatment with an Akt inhibitor. The inhibition of Akt activation reversed the fucoidan-induced decrease in cell proliferation, the induction of G1-phase-associated p21WAF1 expression, and the reduction in cell cycle regulatory protein expression. Intraperitoneal injection of fucoidan reduced tumor volume; this enhanced antitumor efficacy was associated with induction of apoptosis and decreased angiogenesis. These data suggest that the activation of Akt signaling is involved in the growth inhibition of colon cancer cells treated with fucoidan. Thus, fucoidan may serve as a potential therapeutic agent for colon cancer.

• 대한본초학회지
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• 제28권6호
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• pp.155-160
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• 2013

Objectives : Gastric cancer is a leading cause of cancer-related deaths, worldwide. Houttuynia cordata Thunberg (H. cordata) has been used as a medicinal plants and it has an anti-cancer activity in human colorectal cancer and leukemic cancer. However, the potential anti-cancer activity and mechanisms of H. cordata for human gastric cancer cells have not been tested so far. Thus, this study examined the biological effects of H. cordata on the human gastric cancer cell line SNU-1 and AGS. Methods : Inhibition of cell proliferation and cell cycle by H. cordata was carried out by MTT assay and Muse cell cycle analysis and the expressions of protein associated with apoptosis and cell cycle regulation were investigated with Western blot analysis. Results : In MTT assay, the proliferation of SNU-1 and AGS cells was significantly inhibited by H. cordata in a time and dose dependent manner, Inhibition of cell proliferation by H. cordata was in part associated with apoptotic cell death, as shown by changes in the expression ratio of Bax to Bcl-2 by H. cordata. Also, H. cordata regulated the expression of cell cycle regulatory proteins such as pRb, cyclin D1, cyclin E, CDK4, CDK2, p21 and p15. Conclusion : The antiproliferative effect of H. cordata on SNU-1 and AGS gastric cancer cells revealed in this study suggests that H. cordata has intriguing potential as a chemopreventive or chemotherapeutic agent.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8135-8140
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• 2016

Background: Cell cycle regulatory proteins are suitable targets for cancer therapeutic development since genetic alterations in many cancers also affect the functions of these molecules. Strobilanthes crispus (S. crispus) is traditionally known for its potential benefits in treating various ailments. We recently reported that an active sub-fraction of S. crispus leaves (SCS) caused caspase-dependent apoptosis of human breast cancer MCF-7 and MDA-MB-231 cells. Materials and Methods: Considering the ability of SCS to also promote the activity of the antiestrogen, tamoxifen, we further examined the effect of SCS in modulating cell cycle progression and related proteins in MCF-7 and MDA-MB-231 cells alone and in combination with tamoxifen. Expression of cell cycle-related transcripts was analysed based on a previous microarray dataset. Results: SCS significantly caused G1 arrest of both types of cells, similar to tamoxifen and this was associated with modulation of cyclin D1, p21 and p53. In combination with tamoxifen, the anticancer effects involved downregulation of $ER{\alpha}$ protein in MCF-7 cells but appeared independent of an ER-mediated mechanism in MDA-MB-231 cells. Microarray data analysis confirmed the clinical relevance of the proteins studied. Conclusions: The current data suggest that SCS growth inhibitory effects are similar to that of the antiestrogen, tamoxifen, further supporting the previously demonstrated cytotoxic and apoptotic actions of both agents.