• Biomolecules & Therapeutics
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• 제21권2호
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• pp.114-120
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• 2013

Most patients with mutant B-Raf melanomas respond to inhibitors of oncogenic B-Raf but resistance eventually emerges. To better understand the mechanisms that determine the long-term responses of mutant B-Raf melanoma cells to B-Raf inhibitor, we used chronic selection to establish B-Raf (V600E) melanoma clones with acquired resistance to the new oncogenic B-Raf inhibitor UI-152. Whereas the parental A375P cells were highly sensitive to UI-152 ($IC_{50}$ < $0.5{\mu}M$), the resistant sub-line (A375P/Mdr) displayed strong resistance to UI-152 ($IC_{50}$ < $20{\mu}M$). Immunofluorescence analysis indicated the absence of an increase in the levels of P-glycoprotein multidrug resistance (MDR) transporter in A375P/Mdr cells, suggesting that resistance was not attributable to P-glycoprotein overexpression. In UI-152-sensitive A375P cells, the anti-proliferative activity of UI-152 appeared to be due to cell-cycle arrest at $G_0/G_1$ with the induction of apoptosis. However, we found that A375P/Mdr cells were resistant to the apoptosis induced by UI-152. Interestingly, UI-152 preferentially induced autophagy in A375P/Mdr cells but not in A375P cells, as determined by GFP-LC3 puncta/cell counts. Further, autophagy inhibition with 3-methyladenine (3-MA) partially augmented growth inhibition of A375P/Mdr cells by UI-152, which implies that a high level of autophagy may protect UI-152-treated cells from undergoing growth inhibition. Together, our data implicate high rates of autophagy as a key mechanism of acquired resistance to the oncogenic B-Raf inhibitor, in support of clinical studies in which combination therapy with autophagy targeted drugs is being designed to overcome resistance.

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1103-1109
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• 2018

Objective: This study aimed to screen and identify the target genes of miR-375 in pig Sertoli (ST) cells and to elucidate the effect of miR-375 on the proliferation of ST cells. Methods: In this study, bioinformatics software was used to predict and verify miR-375 target genes. Quantitative polymerase chain reaction (PCR) was used to detect the relationship between miR-375 and its target genes in ST cells. Enzyme-linked immunosorbent assay (ELISA) of rearranged L-myc fusion (RLF) and hypoxia-induced gene domain protein 1A (HIGD1A) was performed on porcine ST cells, which were transfected with a miR-375 mimics and inhibitor to verify the results. Dual luciferase reporter gene assays were performed to assess the interactions among miR-375, RLF, and HIGD1A. The effect of miR-375 on the proliferation of ST cells was analyzed by CellTiter 96 AQueous One Solution Cell Proliferation Assay (MTS). Results: Five possible target genes of miR-375, including RLF, HIGD1A, colorectal cancer associated 2, POU class 3 homeobox 1, and WW domain binding protein 1 like, were found. The results of quantitative PCR suggested that mRNA expression of RLF and HIGD1A had a negative correlation with miR-375, indicating that RLF and HIGD1A are likely the target genes of miR-375. The ELISA results revealed that RLF and HIGD1A were negatively correlated with the miR-375 protein level. The luminescence results for the miR-375 group cotransfected with wild-type RLF and HIGD1A vector were significantly lower than those of the miR-375 group co-transfected with the blank vector or mutant RLF and HIGD1A vectors. The present findings suggest that RLF and HIGD1A are target genes of miR-375 and that miR-375 inhibits ST cell proliferation according to MTS analysis. Conclusion: It was speculated that miR-375 affects cell proliferation through its target genes, which play an important role in the development of testicular tissue.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1551-1556
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• 2014

Background: Transient receptor potential melastatin 8 (TRPM8), a principle membrane receptor involved in calcium ion influx and cell signal transduction, has been found to be up-regulated in some cancer types, including melanomas. Efficiency of menthol, an agonist of TRPM8, in killing melanoma cancer cells has been reported previously, but the mechanisms remain unclear. We here determined whether in vitro cytotoxic effects of menthol on A-375 human malignant melanoma cells might be related to TRPM8 transcript expression. Materials and Methods: The $PrestoBlue^{(R)}$ cell viability assay was used to assess the in vitro cytotoxic effect of menthol after 24h of treatment. RT-PCR was used to quantify TRPM8 transcript expression levels in normal and menthol-treated cells. Cell morphology was observed under inverted phase contrast light microscopy. Results: TRPM8 transcript expression was found at low levels in A-375 cells and down-regulated in a potentially dose-dependent manner by menthol. Menthol exerted in vitro cytotoxic effects on A-375 cells with an $IC_{50}$ value of 11.8 ${\mu}M$, which was at least as effective as 5-fluorouracil ($IC_{50}=120{\mu}M$), a commonly applied chemotherapeutic drug. Menthol showed no dose-dependent cytotoxicity on HeLa cells, a TRPM8 non-expressing cell line. Conclusions: The cytotoxic effects on A-375 cells caused by menthol might be related to reduction of the TRPM8 transcript level. This suggests that menthol might activate TRPM8 to increase cytosolic $Ca^{2+}$ levels, which leads to cytosolic $Ca^{2+}$ imbalance and triggers cell death.

• 한국식품위생안전성학회지
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• 제34권2호
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• pp.183-190
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• 2019

우르솔릭산은 항암, 항산화, 항염증 작용과 같은 다양한 효과를 지니고 있다. 본 연구에서는 우르솔릭산이 인간 흑색종 암세포인 A375SM과 A375P 세포에 항암효과가 있는지 확인하였다. 두 세포의 생존율은 MTT assay를 통하여 확인하였으며 증식률은 Wound healing assay로 확인하였다. 두 세포의 apoptotic body와 apoptosis 비율의 확인을 위한 DAPI 염색과 유세포 분석을 진행하였다. 그리고 웨스턴 블로팅을 통하여 흑색종 세포의 우르솔릭산의 농도에 따른 apoptosis 단백질의 유도를 조사하였다. 우르솔릭산의 처리 농도에 따라 흑색종 세포의 생존율 감소와 증식률 감소를 확인하였다. DAPI 염색을 통하여 우르솔릭산의 농도가 증가함에 따라 흑색종 세포의 염색체 응축이 농도 의존적으로 증가하였고, 유세포 분석을 통하여 우르솔릭산에 대하여 농도 의존적으로 흑색종 세포의 apoptosis 비율의 증가를 확인하였다. 그리고 웨스턴 블로팅을 통해 흑색종 세포 A375SM과 A375P의 우르솔릭산 $12{\mu}M$ 농도에서 cleaved-PARP와 Bax의 증가와 Bcl-2의 감소를 확인하였다. 본 연구는 우르솔릭산의 농도를 0 에서 $20{\mu}M$ 수준의 저농도에서 진행하였으며, 물질 처리 후 24 시간 뒤 결과를 가지고 분석하였다. 본 연구의 결과로 보아 우르솔릭산은 흑색종 세포 A375SM과 A375P에서 apoptosis 관련 단백질들의 조절을 통해 항암효과를 일으키는 것으로 사료된다.

• 생명과학회지
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• 제24권8호
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• pp.903-909
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• 2014

본 연구에서는 제주도 한라산에 광범위하게 자생하는 제주조릿대의 항암 제제로써의 이용 가능성을 평가하기 위하여 6개 암세포(A549, MCF-7, HepG-2, Hela, HCT116, A375)를 대상으로 세포주기 교란 작용 및 자연사멸 효과를 탐색하였다. MTT 분석 결과 제주조릿대가 다양한 암세포의 증식을 효과적으로 저해하였으며, sub-G1기의 증가와 DNA 분절로 인한 자연사멸 증가에 산화질소가 연관성이 있었다. 이와 별개로 제주조릿대는 세포주기의 장애를 야기하여 암세포의 생장을 억제하는 것으로 나타나 상기의 결과들로 예측하여 볼 때 제주조릿대를 항암 활성을 지닌 소재로 활용 가능할 것이며, 향후 정확한 자연사멸기전 규명을 위한 연구가 진행되어야 할 것이다.

• Biomolecules & Therapeutics
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• 제23권4호
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• pp.320-326
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• 2015

The clinical benefits of oncogenic BRAF inhibitor therapies are limited by the emergence of drug resistance. In this study, we investigated the role of a negative regulator of the MAPK pathway, Spry2, in acquired resistance using BRAF inhibitor-resistant derivatives of the BRAF-V600E melanoma (A375P/Mdr). Real-time RT-PCR analysis indicated that the expression of Spry2 was higher in A375P cells harboring the BRAF V600E mutation compared with wild-type BRAF-bearing cells (SK-MEL-2) that are resistant to BRAF inhibitors. This result suggests the ability of BRAF V600E to evade feedback suppression in cell lines with BRAF V600E mutations despite high Spry2 expression. Most interestingly, Spry2 exhibited strongly reduced expression in A375P/Mdr cells with acquired resistance to BRAF inhibitors. Furthermore, the overexpression of Spry2 partially restored sensitivity to the BRAF inhibitor PLX4720 in two BRAF inhibitor-resistant cells, indicating a positive role for Spry2 in the growth inhibition induced by BRAF inhibitors. On the other hand, long-term treatment with PLX4720 induced pERK reactivation following BRAF inhibition in A375P cells, indicating that negative feedback including Spry2 may be bypassed in BRAF mutant melanoma cells. In addition, the siRNA-mediated knockdown of Raf-1 attenuated the rebound activation of ERK stimulated by PLX4720 in A375P cells, strongly suggesting the positive role of Raf-1 kinase in ERK activation in response to BRAF inhibition. Taken together, these data suggest that RAF signaling may be released from negative feedback inhibition through interacting with Spry2, leading to ERK rebound and, consequently, the induction of acquired resistance to BRAF inhibitors.

• 한방안이비인후피부과학회지
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• 제32권4호
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• pp.1-12
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• 2019

Objectives : The purpose of this study was to identify the anticancer effect of biological substances of ethylacetate(EtOAc) fraction from Orostachys japonicus(OJEF), their effect on human melanoma A375 cells and the related molecular mechanisms. Methods : The MTS assay was used to confirm the inhibition of cancer cell proliferation in A375 cells. And the $MUSE^{TM}$ analyzer was used to determine the ability of OJEF to induce cell cycle arrest. Western blotting was used to determine the changes in protein expression in A375 cells after treatment with OJEF. Results : OJEF showed cytotoxicity to A375 cells. And cell cycle arrest occurred in G1 phase and G2/M phase owing to inhibition of CDK1, cyclin B1, CDK4, and cyclin D, which are related to cell cycle regulation and cell division control. Conclusion : OJEF is effective in regulating cell cycle of human melanoma cells and thus can be a good theraputic agent to treat patients with melanoma.

• Asian Pacific Journal of Cancer Prevention
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• 제16권10호
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• pp.4329-4333
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• 2015

Background: To investigate the change of frequency and immuno-inhibitory function of myeloid-derived suppressor cells (MDSCs) after treatment of cisplatin (DDP) in A375 human melanoma model. Materials and Methods: BALB/c nude mice were inoculated with A375 cells to establish the human melanoma model and randomly divided into control group given normal saline (NS) and experimental group treated with DDP (5 mg/kg). The percentages of MDSCs in the tumor tissue and peripheral blood after DDP treatment were detected by flow cytometry. The proliferation and interferon-${\gamma}$ (IFN-${\gamma}$) secretion of T cells co-cultured with MDSCs were analyzed through carboxyfluorescein succinimidyl ester (CFSE) labeling assay and enzyme-linked immunospot (ELISPOT) assay, respectively. Results: In A375 human melanoma model, DDP treatment could significantly decrease the percentage of MDSCs in the tumor tissue, but exerted no effect on the level of MDSCs in peripheral blood. Moreover, DDP treatment could attenuate the immuno-inhibitory function of MDSCs. T cells co-cultured with DDP-treated MDSCs could dramatically elevate the proliferation and production of INF-${\gamma}$. Conclusions: DDP can decrease the frequency and attenuate immuno-inhibitory function of MDSCs in A375 melanoma model, suggesting a potential strategy to augment the efficacy of combined immunotherapy.

• Archives of Pharmacal Research
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• 제28권1호
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• pp.68-72
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• 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.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1611-1615
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• 2012

Triptolide, a diterpenoid obtained from Tripteryglum wilfordii Hook.f, has attracted interest for its antitumor activities against human tumor cell lines in recent years. This report focuses on anti-proliferative and pro-apoptotic activities in human melanoma A375 cells assessed by CCK8 assay, Hoechst 33258 staining and flow cytometry. In addition, triptolide-induced arrest in the S phase was also observed. Caspase assays showed the apoptosis induced by triptolide was caspase-dependent and probably through intrinsic apoptotic pathways. Furthermore, expression of NF-${\kappa}B$ (p65) and its downstream factors such as Bcl-2, Bcl-$X_L$ was down-regulated. Taken together, the data indicate that triptolide inhibits A375 cells proliferation and induces apoptosis by a caspase-dependent pathway and through a NF-${\kappa}B$-mediated mechanism.