• Toxicological Research
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• 제14권2호
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• pp.123-127
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• 1998

BRCA1 is a tumor suppresser gene in familial cases of breast cancer. It has been controversial whether the subcellular localization of BRCA1 is located in nuclei or cytoplasm in normal human breast cells. We found that a p220 protein was expressed in Type II Normal human breast epithelial cells (NHBEC) but not in Type I NHBEC in Western blot analysis using the 17F8 (3A2) antibody. Immunostaining using the same antibody revealed positive staining in nuclei, cytoplasm and perinuclei of Type II cells and negative staining in Type I NHBEC. The p220 protein, however, was expressed in SV40 immortalized Type I NHBEC and tumorigenic cells derived from them after x-ray and neu oncogene treatment. The subcelluar localization was mostly cytoplasmic and punctate in the nuclei. The breast carcinoma cell lines, MCF-7 and T47D, also expressed the p220 protein. Using RT-PCR, we observed the expression of BRCA1 mRNA in both Type I and Type II NHBEC. This result indicated that there might be mechanisms involved in post-translational or translational regulation of BRCA1 gene. It is speculated that the absence of BRCA1 protein expression in Type I NHBEC might playa role in their susceptibility to neoplastic transformation.

• Molecules and Cells
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• 제43권5호
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• pp.459-468
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• 2020

Nuclear receptor subfamily group H member 4 (NR1H4), also known as farnesoid X receptor, has been implicated in several cellular processes in the liver and intestine. Preclinical and clinical studies have suggested a role of NR1H4 in colon cancer development; however, how NR1H4 regulates colon cancer cell growth and survival remains unclear. We generated NR1H4 knockout (KO) colon cancer cells using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein-9 nuclease (CAS9) technology and explored the effects of NR1H4 KO in colon cancer cell proliferation, survival, and apoptosis. Interestingly, NR1H4 KO cells showed impaired cell proliferation, reduced colony formation, and increased apoptotic cell death compared to control colon cancer cells. We identified MYC as an important mediator of the signaling pathway alterations induced by NR1H4 KO. NR1H4 silencing in colon cancer cells resulted in reduced MYC protein levels, while NR1H4 activation using an NR1H4 ligand, chenodeoxycholic acid, resulted in time- and dose-dependent MYC induction. Moreover, NR1H4 KO enhanced the anti-cancer effects of doxorubicin and cisplatin, supporting the role of MYC in the enhanced apoptosis observed in NR1H4 KO cells. Taken together, our findings suggest that modulating NR1H4 activity in colon cancer cells might be a promising alternative approach to treat cancer using MYC-targeting agents.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.5977-5982
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• 2014

Research over the years has progressively shown substantial broadening of the tumor necrosis factor alpha-related apoptosis-inducing ligand (TRAIL)-mediated signaling landscape. Increasingly it is being realized that pancreatic cancer is a multifaceted and genomically complex disease. Suppression of tumor suppressors, overexpression of oncogenes, epigenetic silencing, and loss of apoptosis are some of the extensively studied underlying mechanisms. Rapidly accumulating in vitro and in vivo evidence has started to shed light on the resistance mechanisms in pancreatic cancer cells. More interestingly a recent research has opened new horizons of miRNA regulation by DR5 in pancreatic cancer cells. It has been shown that DR5 interacts with the core microprocessor components Drosha and DGCR8, thus impairing processing of primary let-7. Xenografting DR5 silenced pancreatic cancer cells in SCID-mice indicated that there was notable suppression of tumor growth. There is a paradigm shift in our current understanding of TRAIL mediated signaling in pancreatic cancer cells that is now adding new layers of concepts into the existing scientific evidence. In this review we have attempted to provide an overview of recent advances in TRAIL mediated signaling in pancreatic cancer as evidenced by findings of in vitro and in vivo analyses. Furthermore, we discuss nanotechnological advances with emphasis on PEG-TRAIL and four-arm PEG cross-linked hyaluronic acid (HA) hydrogels to improve availability of TRAIL at target sites.

• Preventive Nutrition and Food Science
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• 제5권4호
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• pp.184-188
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• 2000

HMG-CoA reductase is th rate-limiting enzyme of cholesterol biosynthesis. As intracellular levels of cholesterol should be regulated elaborately in response to external stimuli an internal needs, the expression of the HMG-CoA reductase gene is regulated intricately at several different levels from transcription to post-translational modification. In this study, we investigated the regulatory mechanism of HMG-CoA reductase gene expression at the post-transcriptional/pre-translational levels in a baby hamster kidney cell line, C100. when 25-hydroxycholesterol was added to cells cultured in medium containing 5% delipidized fetal bovine serum and 25$\mu$M lovastatin, the levels of HMG-CoA reductase mRNA decreased rapidly, which seemed to be due to the increased degradation of reductase mRNA. These suppressive effects of 25-hydroxycholesterol on MG-CoA reductase mRNA levels were blocked by a translation inhibitor, cycloheximide. Similarly, actinomycin D and 5,6-dichloro-1-$\beta$-D-ribofuranosylbenzimidazole, transcription inhibitors, blocked the 25-hydroxycholesterol-mediated degradation of HMG-CoA reductase mRNA. These results indicate that new protein/RNA synthesis is required for the degradation of HMG-CoA reductase mRNA. In addition, data from the transfection experiments shows that cis-acting determinants, regulating the stability of reductase mRNA, were scattered in the sequence corresponding to 1766-4313 based on the sequence of Syrian hamster HMG-CoA reductase cDNA. Our data suggests that sterol-mediated destabilization of reductase mRNA might be one of the important regulatory mechanism of HMG-CoA reductase gene expression.

• 생명과학회지
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• 제28권3호
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• pp.376-387
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• 2018

식물이 접하는 다양한 환경 스트레스(고온, 저온, 냉해, 고염, 가뭄 등) 중에서 물부족(가뭄) 스트레스는 식물의 생장 및 생산성을 저해하는 가장 주요한 요인으로 보고되어 왔다. 그러므로, 물부족 스트레스에 대한 식물의 반응 기작을 명확히 이해하는 것은 물부족 스트레스 저항성이 증가된 유용 작물 개발에 적용될 수 있을 것으로 기대되며, 그 결과 작물 재배 가능 지역의 확대에 기여할 수 있을 것으로 생각된다. 식물의 물부족 스트레스 신호 과정은 크게 식물 호르몬인 앱시스산 의존적인 과정과 비의존적인 과정으로 분류되며, 각각 AREB/ABF, DREB2 전사 조절 인자가 주요한 전사 조절 인자로 참여하여 하위 단계 반응 유전자의 발현 조절에 참여한다. 이러한 AREB/ABF, DREB2 의존적인 regulon에 대한 연구를 통해 물부족 스트레스 신호 과정 중 전사 수준의 조절에 대한 규명이 활발히 이루어지고 있다. 해당 신호 과정에는 전사 수준의 조절뿐만 아니라 인산화, 유비퀴틴화와 같은 번역 후 변형 과정 및 염색질 변형에 의해 매개되는 후성유전학적 조절도 연관되어 있다. 본 총설에서는 현재까지 보고된 물부족 스트레스 신호 전달 과정을, 이와 관련되어 보고된 다양한 신호 전달 단백질들의 기능과 연계시켜 알아보고자 한다. 이러한 물부족 스트레스 신호 전달 과정에 대한 명확한 이해는 향후 유용 내건성 작물 개발을 위한 이론적 기반 구축에 도움이 될 수 있을 것이라 생각된다.

• 생명과학회지
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• 제27권10호
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• pp.1225-1231
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• 2017

암을 포함한 다양한 인간의 질병 발생이 circadian clock 유전자의 변형된 발현 양상과 깊은 연관관계를 나타내고 있다. 세포 주기와 세포 성장은 circadian rhythm과 연결되어 있으며, 이를 조절하는 clock 유전자의 비정상적인 발현은 결국 종양 발생과 암의 발달을 유발하게 된다. Circadian clock에 관한 분자적 기전은 다수의 clock activator와 clock repressor의 통합적인 조절에 따른 전사 및 번역이 포함된 음성피드백 고리로 구성되어 있다. 이러한 circadian rhythm의 자동조절 기전에 의해 전체 유전체의 약 10~15%가 전사 수준에서 영향받는 것으로 나타났다. 많은 clock 유전자들 중, Period 1 (Per1)과 Period 2 (Per2)는 clock repressor 유전자로 정상적인 생리적 리듬을 조절하는 것에 기여한다. PER1과 PER2는 cyclin, CDK, CKI를 포함하는 세포 주기 조절자의 발현에 관여함이 밝혀졌으며, 다양한 암에서 PER1과 PER2의 발현 감소가 보고되었다. 따라서, 본 논문에서는 PER1과 PER2의 circadian rhythm에서의 분자적 기능과 종양 발생과 관련된 PER1과 PER2의 하위 표적인자에 대해 살펴보고, 암 치료를 위한 새로운 치료 표적과 암의 예후를 예측하기 위한 분자 지표로써의 PER1과 PER2의 가능성에 대해 서술하고자 한다.

• IMMUNE NETWORK
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• 제4권3호
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• pp.166-175
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• 2004

Background: Telomerase, a ribonucleoprotein enzyme capable of synthesizing telomeric repeats, attracts attention for its possible role in determining the replicative capacity of normal somatic cells, transformed cells, and cells of the germline lineage. Differently from normal somatic cells with no telomerase activity, normal lymphocytes has been reported to have telomerase activity comparable to that found in transformed cells during development and activation, which substantiate a role in supporting the capacity of lymphocytes for extensive clonal expansion. Methods: Here, in order to define the telomerase regulation in murine T lymphocytes, telomerase activity in cloned murine $CD8^+$ T cells and naive $CD8^+$ T cells isolated from C57BL/6 mice was examined. Next, the regulatory mechanism of telomerase activity at transcriptional and post- translational levels was investigated by determining the expression level of the TERT protein, a key component for telomerase activity. Results: It was demonstrated that telomerase activity was expressed in an inactivated state as well as in an activated state in the murine $CD8^+$ T lymphocytes by using TRAP assay. The increase of telomerase activity was partially dependent on the net increase of TERT expression. Also, telomerase activity was decreased after treatment with protein kinase inhibitors, indicating that telomerase activation was prevented by inhibition of phosphorylation. Conclusion: Therefore, these results suggest that telomerase activity is constitutively expressed in the murine resting T lymphocytes and controlled by both transcriptional regulation and post- ranslational modifications.

• Asian Pacific Journal of Cancer Prevention
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• 제13권2호
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• pp.591-598
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• 2012

Aim and background: MicroRNAs (miRNAs) are a class of naturally occurring small noncoding RNAs that regulate gene expression, cell growth, differentiation and apoptosis by targeting mRNAs for translational repression or cleavage. The present study was conducted to study miRNAs in Egyptian breast cancer (BC) and their relation to metastasis, tumor invasion and apoptosis in addition to their association with the ER and PR statuses. Methods: Real Time RT-PCR was performed to identify the miRNA expression level of eight miRNAs and eight metastatic-related genes in 40 breast cancer samples and their adjacent non-neoplastic tissues. The expression levels of each miRNA relative to U6 RNA were determined using the $^{2-{\Delta}}CT$ method. Also, miRNA expression profiles of the BC and their corresponding ANT were evaluated. Results: The BC patients showed an up-regulation in miRNAs (mir-155, mir-10, mir-21 and mir-373) with an upregulation in MMP2, MMp9 and VEGF genes. We found down regulation in mir-17p, mir-126, mir-335, mir-30b and also TIMP3, TMP1 and PDCD4 genes in the cancer tissue compared to the adjacent non-neoplastic tissues. Mir -10b, mir -21, mir-155 and mir373 and the metastatic genes MMP2, MMP9 and VEGF were significantly associated with an increase in tumor size (P < 0.05). No significant difference was observed between any of the studied miRNAs regarding lymph node metastasis. Mir-21 was significantly over-expressed in ER-/PR-cases. Conclusion: Specific miRNAs (mir-10, mir-21, mir-155, mir-373, mir-30b, mir-126, mir-17p, mir-335) are associated with tumor metastasis and other clinical characteristics for BC, facilitating identification of individuals who are at risk.

• BMB Reports
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• 제36권3호
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• pp.326-331
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• 2003

The fission yeast cells that contained the cloned glutathione synthetase (GS) gene showed 1.4-fold higher glutathione (GSB) content and 1.9-fold higher GS activity than the cells without the cloned GS gene. Interestingly, $\gamma$-glutamylcysteine synthetase activity increased 2.1-fold in the S. pombe cells that contained the cloned GS gene. The S. pombe cells that harbored the multi copy-number plasmid pRGS49 (containing the cloned GS gene) showed a higher level of survival on solid media with cadmium chloride (1 mM) or mercuric chloride ($10\;{\mu}M$) than the cells that harbored the YEp357R vector. The 506 bp upstream sequence from the translational initiation point and N-terminal8 amino acid-coding region were fused into the promoteriess $\beta$-galactosidase gene of the shuttle vector YEp367R to generate the fusion plasmid pUGS39. Synthesis of $\beta$-galactosidase from the fusion plasmid pUGS39 was significantly enhanced by cadmium chloride and NO-generating S-nitroso-N-acetylpenicillamine (SNAP) and sodium nitroprusside (SN). It was also induced by L-buthionine-(S,R)-sulfoximine, a specific inhibitor of $\gamma$-glutamylcysteine synthetase (GCS). We also found that the expression of the S. pombe GS gene is regulated by the Atf1-Spc1-Wis1 signal pathway.

• Asian Pacific Journal of Cancer Prevention
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• 제14권3호
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• pp.2113-2118
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• 2013

Aim and Background: Cervical cancer remains the third most common cancer in women globally after breast and colorectal cancer. Well-characterized biomarkers are necessary for early diagnosis and to predict metastatic progression and effective therapy. MiRNAs can regulate gene expression, cell growth, differentiation and apoptosis by targeting mRNAs for translational repression or degradation in tumor cells. The present study was conducted to assess expression of miR93, miR200a, RECK, MMP2, MMP9 in invasive cervical carcinoma, and analyze their clinical significance. Method: A total of 116 patients with invasive cervical carcinoma and 100 patients undergoing hysterectomy for benign lesions were retrospectively examined. Quantitative real-time PCR was performed to determine expression of miR93 and miR200a while RECK, MMP2, MMP9 and MVD were assessed by immunohistochemical staining. Results: Cervical carcinoma patients demonstrated up-regulation of miR-93, miR-200a, MMP2 and MMP9, with down-regulation of RECK as compared to benign lesion tissues. RECK was significantly inversely related to invasion and lymphatic metastasis. The 5-year survival rate for patients with strong RECK expression was significantly higher than that with weakly expressing tumors. Conclusion: MiR-93 and miR-200a are associated with metastasis and invasion of cervical carcinoma. Thus together with RECK they are potential prognostic markers for cervical carcinoma. RECK cooperating with MMP2, MMP9 expression is a significant prognostic factor correlated with long-term survival for patients with invasive cervical carcinoma.