• Archives of Pharmacal Research
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• 제19권3호
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• pp.213-218
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• 1996

Multidrug resistance (MDR) has been a major problem in cancer chemotherapy. To overcome this problem, we prepared minor ginsenosides stereoselectively from ginseng saponins and searched for a ginseng component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level of mdr1 gene. Of several ginseng components, 20(S)-ginsenoside Rg_3$, a red ginseng saponin, was found to have the most potent inhibitory activity on MDR and it's concentration capable of inhibiting 50% growth was $82\muM$.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.559-569
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• 2021

As one of the major types of lung cancer, non-small cell lung cancer (NSCLC) accounts for the majority of cancer-related deaths worldwide. Treatments for NSCLC includes surgery, chemotherapy, and targeted therapy. Among the targeted therapies, resistance to inhibitors of the epidermal growth factor receptor (EGFR) is common and remains a problem to be solved. MET (hepatocyte growth factor receptor) amplification is one of the major causes of EGFR-tyrosine kinase inhibitor (TKI) resistance. Therefore, there exists a need to find new and more efficacious therapies. Deoxypodophyllotoxin (DPT) extracted from Anthriscus sylvestris roots exhibits various pharmacological activities including anti-inflammation and anti-cancer effects. In this study we sought to determine the anti-cancer effects of DPT on HCC827GR cells, which are resistant to gefitinib (EGFR-TKI) due to regulation of EGFR and MET and their related signaling pathways. To identify the direct binding of DPT to EGFR and MET, we performed pull-down, ATP-binding, and kinase assays. DPT exhibited competitive binding with ATP against the network kinases EGFR and MET and reduced their activities. Also, DPT suppressed the expression of p-EGFR and p-MET as well as their downstreat proteins p-ErbB3, p-AKT, and p-ERK. The treatment of HCC827GR cells with DPT induced high ROS generation that led to endoplasmic-reticulum stress. Accordingly, loss of mitochondrial membrane potential and apoptosis by multi-caspase activation were observed. In conclusion, these results demonstrate the apoptotic effects of DPT on HCC827GR cells and signify the potential of DPT to serve as an adjuvant anti-cancer drug by simultaneously inhibiting EGFR and MET.

• Journal of Gastric Cancer
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• 제24권1호
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• pp.29-56
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• 2024

In recent years, remarkable progress has been made in the molecular profiling of gastric cancer. This progress has led to the development of various molecular classifications to uncover subtype-specific dependencies that can be targeted for therapeutic interventions. Human epidermal growth factor receptor 2 (HER2) is a crucial biomarker for advanced gastric cancer. The recent promising results of novel approaches, including combination therapies or newer potent agents such as antibody-drug conjugates, have once again brought attention to anti-HER2 targeted treatments. In HER2-negative diseases, the combination of cytotoxic chemotherapy and programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors has become the established standard of care in first-line settings. In the context of gastric cancer, potential biomarkers such as PD-L1 expression, Epstein-Barr virus, microsatellite instability, and tumor mutational burden are being considered for immunotherapy. Recently, promising results have been reported in studies on anti-Claudin18.2 and fibroblast growth factor receptor 2 treatments. Currently, many ongoing trials are aimed at identifying potential targets using novel approaches. Further investigations will be conducted to enhance the progress of these therapies, addressing challenges such as primary and acquired resistance, tumor heterogeneity, and clonal evolution. We believe that these efforts will improve patient prognoses. Herein, we discuss the current evidence of potential targets for systemic treatment, clinical considerations, and future perspectives.

• The Korean Journal of Physiology and Pharmacology
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• 제26권3호
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• pp.145-155
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• 2022

Multidrug resistance of tumors has been a severe obstacle to the success of cancer chemotherapy. The study wants to investigate the reversal effects of imperatorin (IMP) on doxorubicin (DOX) resistance in K562/DOX leukemia cells, A2780/Taxol cells and in NOD/SCID mice, to explore the possible molecular mechanisms. K562/DOX and A2780/Taxol cells were treated with various concentrations of DOX and Taol with or without different concentrations of IMP, respectively. K562/DOX xenograft model was used to assess anti-tumor effect of IMP combined with DOX. MTT assay, Rhodamine 123 efflux assay, RT-PCR, and Western blot analysis were determined in vivo and in vitro. Results showed that IMP significantly enhanced the cytotoxicity of DOX and Taxol toward corresponding resistance cells. In vivo results illustrated both the tumor volume and tumor weight were significantly decreased after 2-week treatment with IMP combined with DOX compared to the DOX alone group. Western blotting and RT-PCR analyses indicated that IMP downregulated the expression of P-gp in K562/DOX xenograft tumors in NOD/SCID mice. We also evaluated glycolysis and glutamine metabolism in K562/DOX cells by measuring glucose consumption and lactate production. The results revealed that IMP could significantly reduce the glucose consumption and lactate production of K562/DOX cells. Furthermore, IMP could also remarkably repress the glutamine consumption, α-KG and ATP production of K562/DOX cells. Thus, IMP may sensitize K562/DOX cells to DOX and enhance the antitumor effect of DOX in K562/DOX xenograft tumors in NOD/SCID mice. IMP may be an adjuvant therapy to mitigate the multidrug resistance in leukemia chemotherapy.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8467-8471
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• 2016

Background: One of the major mechanisms for drug resistance is associated with altered anticancer drug transport, mediated by the human-adenosine triphosphate binding cassette (ABC) transporter superfamily proteins. The overexpression of adenosine triphosphate binding cassette, sub-family B, member 1 (ABCB1) by multidrug-resistant cancer cells is a serious impediment to chemotherapy. In our study we have studied the possibility that structural single-nucleotide polymorphisms (SNP) are the mechanism of ABCB1 overexpression. Materials and Methods: A total of 101 gastric cancer multidrug resistant cases and 100 controls were genotyped with sequence-specific primed PCR (SSP-PCR). Gene expression was evaluated for 70 multidrug resistant cases and 54 controls by real time PCR. The correlation between the two groups was based on secondary structures of RNA predicted by bioinformatics tool. Results: The results of genotyping showed that among 3 studied SNPs, rs28381943 and rs2032586 had significant differences between patient and control groups but there were no differences in the two groups for C3435T. The results of real time PCR showed over-expression of ABCB1 when we compared our data with each of the genotypes in average mode. Prediction of secondary structures in the existence of 2 related SNPs (rs28381943 and rs2032586) showed that the amount of ${\Delta}G$ for original mRNA is higher than the amount of ${\Delta}G$ for the two mentioned SNPs. Conclusions: We have observed that 2 of our studied SNPs (rs283821943 and rs2032586) may elevate the expression of ABCB1 gene, through increase in mRNA stability, while this was not the case for C3435T.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.925-928
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• 2014

Background: Gestational trophoblastic neoplasia (GTN) is a spectrum of disease with abnormal trophoblastic proliferation. Treatment is based on FIGO stage and WHO risk factor scores. Patients whose score is 12 or more are considered as at extremely high risk with a high likelihood of resistance to first line treatment. Optimal therapy is therefore controversial. Objective: This study was conducted in order to summarize the regimen used for extremely high risk or resistant GTN patients in our institution the in past 10 years. Materials and Methods: All the charts of GTN patients classified as extremely high risk, recurrent or resistant during 1 January 2002 to 31 December 2011 were reviewed. Criteria for diagnosis of GTN were also assessed to confirm the diagnosis. FIGO stage and WHO risk prognostic score were also re-calculated to ensure the accuracy of the information. Patient characteristics were reviewed in the aspects of age, weight, height, BMI, presenting symptoms, metastatic area, lesions, FIGO stage, WHO risk factor score, serum hCG level, treatment regimen, adjuvant treatments, side effects and response to treatment, including disease free survival. Results: Eight patients meeting the criteria of extremely high risk or resistant GTN were included in this review. Mean age was 33.6 years (SD=13.5, range 17-53). Of the total, 3 were stage III (37.5%) and 5 were stage IV (62.5%). Mean duration from previous pregnancies to GTN was 17.6 months (SD 9.9). Mean serum hCG level was 864,589 mIU/ml (SD 98,151). Presenting symptoms of the patients were various such as hemoptysis, abdominal pain, headache, heavy vaginal bleeding and stroke. The most commonly used first line chemotherapeutic regimen in our institution was the VAC regimen which was given to 4 of 8 patients in this study. The most common second line chemotherapy was EMACO. Adjuvant radiation was given to most of the patients who had brain metastasis. Most of the patients have to delay chemotherapy for 1-2 weeks due to grade 2-3 leukopenia and require G-CSF to rescue from neutropenia. Five form 8 patients were still survived. Mean of disease free survival was 20.4 months. Two patients died of the disease, while another one patient died from sepsis of pressure sore wound. None of surviving patients developed recurrence of disease after complete treatment. Conclusions: In extremely high risk GTN patients, main treatment is multi-agent chemotherapy. In our institution, we usually use VAC as a first line treatment of high risk GTN, but since resistance is quite common, this may not suitable for extremely high risk GTN patients. The most commonly used second line multi-agent chemotherapy in our institution is EMA-CO. Adjuvant brain radiation was administered to most of the patients with brain metastasis in our institution. The survival rate is comparable to previous reviews. Our treatment demonstrated differences from other institutions but the survival is comparable. The limitation of this review is the number of cases is small due to rarity of the disease. Further trials or multicenter analyses may be considered.

• Journal of Ginseng Research
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• 제44권2호
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• pp.247-257
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• 2020

Background: Multidrug resistance (MDR) to chemotherapy drugs remains a major challenge in clinical cancer treatment. Here we investigated whether and how ginsenoside Rg5 overcomes the MDR mediated by ABCB1 transporter in vitro and in vivo. Methods: Cytotoxicity and colon formation as well as the intracellular accumulation of ABCB1 substrates were carried out in MDR cancer cells A2780/T and A549/T for evaluating the reversal effects of Rg5. The expressions of ABCB1 and Nrf2/AKT pathway were determined by Western blotting. An A549/T cell xenograft model was established to investigate the MDR reversal activity of Rg5 in vivo. Results: Rg5 significantly reversed ABCB1-mediated MDR by increasing the intracellular accumulation of ABCB1 substrates without altering protein expression of ABCB1. Moreover, Rg5 activated ABCB1 ATPase and reduced verapamil-stimulated ATPase activity, suggesting a high affinity of Rg5 to ABCB1 binding site which was further demonstrated by molecular docking analysis. In addition, co-treatment of Rg5 and docetaxel (TXT) suppressed the expression of Nrf2 and phosphorylation of AKT, indicating that sensitizing effect of Rg5 associated with AKT/Nrf2 pathway. In nude mice bearing A549/T tumor, Rg5 and TXT treatment significantly suppressed the growth of drug-resistant tumors without increase in toxicity when compared to TXT given alone at same dose. Conclusion: Therefore, combination therapy of Rg5 and chemotherapy drugs is a strategy for the adjuvant chemotherapy, which encourages further pharmacokinetic and clinical studies.

• Asian Pacific Journal of Cancer Prevention
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• 제15권24호
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• pp.10597-10601
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• 2015

Up-regulation of multidrug resistance-associated protein 1 (MRP1) is regarded as one of the main causes for multidrug resistance (MDR) of tumor cells, leading to failure of chemotherapy-based treatment for a multitude of cancers. However, whether silencing the overexpressed MRP1 is sufficient to reverse MDR has yet to be validated. This study demonstrated that RNAi-based knockdown of MRP1 reversed the increased efflux ability and MDR efficiently. Two different short haipin RNAs (shRNAs) targeting MRP1 were designed and inserted into pSilence-2.1-neo. The shRNA recombinant plasmids were transfected into cis-dichlorodiamineplatinum-resistant A549 lung (A549/DDP) cells, and then shRNA expressing cell clones were collected and maintained. Real time PCR and immunofluorescence staining for MRP1 revealed a high silent efficiency of these two shRNAs. Functionally, shRNA-expressing cells showed increased rhodamine 123 retention in A549/DDP cells, indicating reduced efflux ability of tumor cells in the absence of MRP1. Consistently, MRP1-silent cells exhibited decreased resistance to 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and DDP, suggesting reversal of MDR in these tumor cells. Specifically, MRP1 knockdown increased the DDP-induced apoptosis of A549/DDP cells by increased trapping of their cell cycling in the G2 stage. Taken together, this study demonstrated that RNAi-based silencing of MRP1 is sufficient to reverse MDR in tumor cells, shedding light on possible novel clinical treatment of cancers.

• 대한골관절종양학회지
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• 제3권2호
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• pp.69-79
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• 1997

Objective : The objective of this study was to compare expression of various proto-oncogenes and rates of apoptosis in osteosarcoma patients. Modulation of apoptosis may influence resistance to chemotherapy and therefore affect the outcome of cancer treatment. Osteosarcoma is one of the most fatal malignancies in young adolescents and investigation of the role of apoptotic cell death is warranted in relation to chemotherapy and tumor outcome. Design : The terminal deoxynucleotidyl transferase to exposed 3'-hydroxyl termini of DNA (TUNEL method) staining method has been applied for the in situ detection of DNA double strand breaks. Patients : Thirty-three osteosarcomas in various stages of differentiation from twenty-nine patients were investigated immunohistochemically for p53, Bcl-2 and TUNEL method for apoptosis. Results and conclusion; We have found that higher level of wild type p53 were correlated with enhanced expression of apoptosis. Increased apoptosis rates were found in cases of negative Bcl-2 expression. In the present study, we have concluded that a significant proportion of osteosarcoma, a tumor in which resistance to chemotherapy often occurs, express high levels of p53 and low levels of Bcl-2. Our data provide further evidence for cross-talk between Bcl-2 and p53 and suggests that these genes are important determinants of drug-induced apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2027-2033
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• 2014

Background: We aimed to assess RET proto-oncogene polymorphisms in three different Iranian families with medullary thyroid cancer (MTC), and performed molecular dynamics simulations and free energy stability analysis of these mutations. Materials and Methods: This study consisted of 48 patients and their first-degree relatives with MTC confirmed by pathologic diagnosis and surgery. We performed molecular dynamics simulations and free energy stability analysis of mutations, and docking evaluation of known RET proto-oncogene inhibitors, including ZD-6474 and ponatinib, with wild-type and mutant forms. Results: The first family consisted of 27 people from four generations, in which nine had the C.G2901A (P.C634Y) mutation; the second family consisted of six people, of whom three had the C.G2901T (P.C634F) mutation, and the third family, who included 12 individuals from three generations, three having the C.G2251A (P.G691S) mutation. The automated 3D structure of RET protein was predicted using I-TASSER, and validated by various protein model verification programs that showed more than 96.3% of the residues in favored and allowed regions. The predicted instability indices of the mutated structures were greater than 40, which reveals that mutated RET protein is less thermo-stable compared to the wild-type form (35.4). Conclusions: Simultaneous study of the cancer mutations using both in silico and medical genetic procedures, as well as onco-protein inhibitor binding considering mutation-induced drug resistance, may help in better overcoming chemotherapy resistance and designing innovative drugs.