BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, ...BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines. METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real- time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis. RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non- pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.展开更多
Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells....Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells.BCRP physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis barriers.BCRP recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical use.Thus,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer drugs.Because BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor prognosis.Therefore,blocking BCRP-mediated active efflux may provide a therapeutic benefit for cancers.Delineating the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated MDR.Current evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated receptor.Furthermore,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer cells.Finally,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of conditions.These biological events seem involved in a complicated manner.Untangling the events would be an essential first step to developing a method to modulate BCRP function to aid patients with cancer.This review will present a synopsis of the impact of BCRP-mediated MDR in ca展开更多
背景与目的:三磷酸腺苷结合盒转运体成员ABCG2(ATP-binding cassette superfamily G member2)是源于造血干细胞的标志物之一,其在神经胶质瘤发生发展相关组织和细胞中的表达情况还不清楚。本研究检测ABCG2在不同恶性程度人脑胶质瘤组织...背景与目的:三磷酸腺苷结合盒转运体成员ABCG2(ATP-binding cassette superfamily G member2)是源于造血干细胞的标志物之一,其在神经胶质瘤发生发展相关组织和细胞中的表达情况还不清楚。本研究检测ABCG2在不同恶性程度人脑胶质瘤组织标本、裸小鼠移植瘤标本、体外细胞系球体和胶质瘤干细胞球体中的表达情况并分析其意义。方法:制作布有不同恶性程度人脑胶质瘤组织标本、裸小鼠移植瘤标本、体外细胞系球体和胶质瘤干细胞球体等的组织芯片,用免疫组化方法检测ABCG2在组织芯片中的表达情况。结果:在71例人脑胶质瘤组织标本中ABCG2的阳性率为26.8%,其中Ⅰ级11.1%,Ⅱ级8.0%,Ⅲ级43.5%,Ⅳ级42.9%;Ⅰ～Ⅱ级与Ⅲ～Ⅳ级相比差异具有统计学意义(%2=10.710,P=0.001)。在神经干细胞、裸小鼠移植瘤、胶质瘤干细胞球体表达率为100%。在多种正常组织中亦有不同程度的表达。在胶质瘤临床标本中ABCG2阳性细胞呈亲血管分布。结论:ABCG2在胶质瘤干细胞、恶性程度高的胶质瘤组织标本和移植瘤组织中高表达,并且呈亲血管分布。展开更多
Uric acid is the end product of purine catabolism and its plasma levels are maintained below its maximum solubility in water(6–7 mg/dl).The plasma levels are tightly regulated as the balance between the rate of produ...Uric acid is the end product of purine catabolism and its plasma levels are maintained below its maximum solubility in water(6–7 mg/dl).The plasma levels are tightly regulated as the balance between the rate of production and the rate of excretion,the latter occurring in urine(kidney),bile(liver)and feces(intestinal tract).Reabsorption in kidney is also an important component of this process.Both excretion and reabsorption are mediated by specific transporters.Disruption of the balance between production and excretion leads to hyperuricemia,which increases the risk of uric acid crystallization as monosodium urate with subsequent deposition of the crystals in joints causing gouty arthritis.Loss-of-function mutations in the transporters that mediate uric acid excretion are associated with gout.The ATP-Binding Cassette exporter ABCG2 is important in uric acid excretion at all three sites:kidney(urine),liver(bile),and intestine(feces).Mutations in this transporter cause gout and these mutations occur at significant prevalence in general population.However,mutations that are most prevalent result only in partial loss of transport function.Therefore,if the expression of these partially defective transporters could be induced,the increased number of the transporter molecules would compensate for the mutation-associated decrease in transport function and hence increase uric acid excretion.As such,pharmacologic agents with ability to induce the expression of ABCG2 represent potentially a novel class of drugs for treatment of gouty arthritis.展开更多
Drug-metabolizing enzymes, transporters, and nuclear receptors are essential for the absorption, distribution, metabolism, and excretion(ADME) of drugs and xenobiotics. MicroRNAs participate in the regulation of ADME ...Drug-metabolizing enzymes, transporters, and nuclear receptors are essential for the absorption, distribution, metabolism, and excretion(ADME) of drugs and xenobiotics. MicroRNAs participate in the regulation of ADME gene expression via imperfect complementary Watson–Crick base pairings with target transcripts. We have previously reported that Cytochrome P450 3A4(CYP3A4) and ATP-binding cassette sub-family G member 2(ABCG2) are regulated by miR-27b-3p and miR-328-3p,respectively. Here we employed our newly established RNA bioengineering technology to produce bioengineered RNA agents(BERA), namely BERA/miR-27b-3p and BERA/miR-328-3p, via fermentation. When introduced into human cells, BERA/miR-27b-3p and BERA/miR-328-3p were selectively processed to target miRNAs and thus knock down CYP3A4 and ABCG2 mRNA and their protein levels,respectively, as compared to cells treated with vehicle or control RNA. Consequently, BERA/miR-27b-3p led to a lower midazolam 10-hydroxylase activity, indicating the reduction of CYP3A4 activity. Likewise,BERA/miR-328-3p treatment elevated the intracellular accumulation of anticancer drug mitoxantrone, a classic substrate of ABCG2, hence sensitized the cells to chemotherapy. The results indicate that biologic miRNA agents made by RNA biotechnology may be applied to research on miRNA functions in the regulation of drug metabolism and disposition that could provide insights into the development of more effective therapies.展开更多
Gastric cancer is a leading cause of cancer-related mortality worldwide, and options to treat gastric cancer are limited. Fluorouracil （SFu）-based chemotherapy is frequently used as a neoadjuvant or an adjuvant agen...Gastric cancer is a leading cause of cancer-related mortality worldwide, and options to treat gastric cancer are limited. Fluorouracil （SFu）-based chemotherapy is frequently used as a neoadjuvant or an adjuvant agent for gastric cancer therapy. Most patients with advanced gastric cancer eventually suc- cumb to the disease despite the fact that some patients respond initially to chemotherapy. Thus, iden- tifying molecular mechanisms responsible for chemotherapy resistance will help design novel strategies to treat gastric cancer. In this study, we discovered that residual cancer ceils following 5Fu treatment have elevated expression of hedgehog （Hg） target genes GLII and GLI2, suggestive of Hh signaling activation, Hh signaling, a pathway essential for embryonic development, is an important regulator for putative cancer stem cells/residual cancer cells. We found that high GLI1/GLI2 expression is associated with some features of putative cancer stem cells, such as increased side population. We demonstrated that GLI2 knockdown sensitized gastric cancer cells to 5Fu treatment, decreased ABCG2 expression, and reduced side population. Elevated Gtl2 expression is also associated with an increase in tumor sphere size, another marker for putative cancer stem cells. We believe that GLI2 regulates putative cancer stem cells through direct regulation ofABCG2. ABCG2 can rescue the GLI2 shRNA effects in 5Fu response, tumor sphere formation and side population changes, suggesting that ABCG2 is an important mediator for GLI2- associated 5Fu resistance. The relevance of our studies to gastric cancer patient care is reflected by our discovery that high GLI1/GLI2/ABCG2 expression is associated with a high incidence of cancer relapse in two cohorts of gastric cancer patients who underwent chemotherapy （containing 5Fu）. Taken together, we have identified a molecular mechanism by which gastric cancer cells gain SFu resistance. Copyright 2017, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, a展开更多
Overexpressing of ATP-binding cassette(ABC) transporters is the essential cause of multidrug resistance(MDR), which is a significant hurdle to the success of chemotherapy in many cancers.Therefore, inhibiting the acti...Overexpressing of ATP-binding cassette(ABC) transporters is the essential cause of multidrug resistance(MDR), which is a significant hurdle to the success of chemotherapy in many cancers.Therefore, inhibiting the activity of ABC transporters may be a logical approach to circumvent MDR.Olmutinib is an epidermal growth factor receptor(EGFR) tyrosine kinase inhibitor(TKI), which has been approved in South Korea for advanced EGFR T790 M-positive non-small cell lung cancer(NSCLC). Here,we found that olmutinib significantly increased the sensitivity of chemotherapy drug in ABCG2-overexpressing cells. Furthermore, olmutinib could also increase the retention of doxorubicin(DOX) and rhodamine 123(Rho 123) in ABC transporter subfamily G member 2(ABCG2)-overexpressing cells. In addition, olmutinib was found to stimulate ATPase activity and inhibit photolabeling of ABCG2 with [^(125) I]-iodoarylazidoprazosin(IAAP). However, olmutinib neither altered ABCG2 expression at protein and m RNA levels nor blocked EGFR, Her-2 downstream signaling of AKT and ERK. Importantly,olmutinib enhanced the efficacy of topotecan on the inhibition of S1-MI-80 cell xenograft growth. All the results suggest that olmutinib reverses ABCG2-mediated MDR by binding to ATP bind site of ABCG2 and increasing intracellular chemotherapeutic drug accumulation. Our findings encouraged to further clinical investigation on combination therapy of olmutinib with conventional chemotherapeutic drugs in ABCG2-overexpressing cancer patients.展开更多
目的探讨干细胞标志物三磷酸腺苷结合盒超家族G家族第2个成员(ATP-binding cassette super-family G member 2,ABCG2)在人肝癌细胞株中的表达及其与肝癌耐药的关系,观察人肝癌细胞株中ABCG2阳性表达和阴性表达细胞的功能差异。方法流式...目的探讨干细胞标志物三磷酸腺苷结合盒超家族G家族第2个成员(ATP-binding cassette super-family G member 2,ABCG2)在人肝癌细胞株中的表达及其与肝癌耐药的关系,观察人肝癌细胞株中ABCG2阳性表达和阴性表达细胞的功能差异。方法流式细胞仪检测ABCG2在人肝癌细胞株PLC/PRF/5、7402、7701及7721中的阳性表达,计算5-氟尿嘧啶(5-FU)、阿霉素的半数抑制浓度(IC50)值。采用免疫荧光染色观察ABCG2在肝癌7721细胞株中的表达,并进行无菌流式分选,观察ABCG2阳性表达与ABCG2阴性表达的肝癌7721细胞的功能差异。结果在4种肝癌细胞株中7721细胞株ABCG2表达阳性率最高(P<0.05),且流式细胞图中阳性表达和阴性表达细胞呈明显双峰。5-FU、阿霉素对7721细胞株的IC50值明显高于其他3种细胞株,除与5-FU对7701细胞的IC50值差异无统计学意义(P>0.05)外,其余比较差异均有统计学意义(P<0.05)。分选后的ABCG2阳性表达细胞与阴性表达细胞的增殖差异无统计学意义(P>0.05);ABCG2阳性表达细胞较阴性表达细胞更多处于相对静止期(P<0.05)。结论 ABCG2在人多种肝癌细胞株中均表达,ABCG2表达阳性率越高的细胞较表达阳性率越低的细胞更具有耐药性,ABCG2阳性表达细胞处于相对静止期。展开更多
Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-b...Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-binding cassette(ABC) transporters,which can increase efflux of drugs from cancer cells,thereby decreasing intracellular drug concentration.Modulators of ABC transporters have the potential to augment the efficacy of anticancer drugs.This editorial highlights some major findings related to ABC transporters and current strategies to overcome MDR.展开更多
文摘BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines. METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real- time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis. RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non- pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.
文摘Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells.BCRP physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis barriers.BCRP recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical use.Thus,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer drugs.Because BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor prognosis.Therefore,blocking BCRP-mediated active efflux may provide a therapeutic benefit for cancers.Delineating the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated MDR.Current evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated receptor.Furthermore,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer cells.Finally,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of conditions.These biological events seem involved in a complicated manner.Untangling the events would be an essential first step to developing a method to modulate BCRP function to aid patients with cancer.This review will present a synopsis of the impact of BCRP-mediated MDR in ca
文摘背景与目的:三磷酸腺苷结合盒转运体成员ABCG2(ATP-binding cassette superfamily G member2)是源于造血干细胞的标志物之一,其在神经胶质瘤发生发展相关组织和细胞中的表达情况还不清楚。本研究检测ABCG2在不同恶性程度人脑胶质瘤组织标本、裸小鼠移植瘤标本、体外细胞系球体和胶质瘤干细胞球体中的表达情况并分析其意义。方法:制作布有不同恶性程度人脑胶质瘤组织标本、裸小鼠移植瘤标本、体外细胞系球体和胶质瘤干细胞球体等的组织芯片,用免疫组化方法检测ABCG2在组织芯片中的表达情况。结果:在71例人脑胶质瘤组织标本中ABCG2的阳性率为26.8%,其中Ⅰ级11.1%,Ⅱ级8.0%,Ⅲ级43.5%,Ⅳ级42.9%;Ⅰ～Ⅱ级与Ⅲ～Ⅳ级相比差异具有统计学意义(%2=10.710,P=0.001)。在神经干细胞、裸小鼠移植瘤、胶质瘤干细胞球体表达率为100%。在多种正常组织中亦有不同程度的表达。在胶质瘤临床标本中ABCG2阳性细胞呈亲血管分布。结论:ABCG2在胶质瘤干细胞、恶性程度高的胶质瘤组织标本和移植瘤组织中高表达,并且呈亲血管分布。
基金This work was supported by the National Institutes of Health grant R41 AR074854the Welch Endowed Chair in Biochemistry,Grant No.BI-0028,at Texas Tech University Health Sciences Center.
文摘Uric acid is the end product of purine catabolism and its plasma levels are maintained below its maximum solubility in water(6–7 mg/dl).The plasma levels are tightly regulated as the balance between the rate of production and the rate of excretion,the latter occurring in urine(kidney),bile(liver)and feces(intestinal tract).Reabsorption in kidney is also an important component of this process.Both excretion and reabsorption are mediated by specific transporters.Disruption of the balance between production and excretion leads to hyperuricemia,which increases the risk of uric acid crystallization as monosodium urate with subsequent deposition of the crystals in joints causing gouty arthritis.Loss-of-function mutations in the transporters that mediate uric acid excretion are associated with gout.The ATP-Binding Cassette exporter ABCG2 is important in uric acid excretion at all three sites:kidney(urine),liver(bile),and intestine(feces).Mutations in this transporter cause gout and these mutations occur at significant prevalence in general population.However,mutations that are most prevalent result only in partial loss of transport function.Therefore,if the expression of these partially defective transporters could be induced,the increased number of the transporter molecules would compensate for the mutation-associated decrease in transport function and hence increase uric acid excretion.As such,pharmacologic agents with ability to induce the expression of ABCG2 represent potentially a novel class of drugs for treatment of gouty arthritis.
基金supported in part by the National Institutes of Health [Grant No. R01GM113888 (Aiming Yu), USA]supported by Visiting Scholar Programs from China Scholarship Council (201608440507, USA) Guangzhou Medical University+2 种基金National Natural Science Foundation of China (81603191, China)Natural Science Foundation of Guangdong Province (2015A030310153, China)supported by the 3102018zy053 from Fundamental Research Funds for the Central Universities (China)funded by the UC Davis Comprehensive Cancer Center Support Grant (CCSG) awarded by the National Cancer Institute (Grant No. P30CA093373, USA)
文摘Drug-metabolizing enzymes, transporters, and nuclear receptors are essential for the absorption, distribution, metabolism, and excretion(ADME) of drugs and xenobiotics. MicroRNAs participate in the regulation of ADME gene expression via imperfect complementary Watson–Crick base pairings with target transcripts. We have previously reported that Cytochrome P450 3A4(CYP3A4) and ATP-binding cassette sub-family G member 2(ABCG2) are regulated by miR-27b-3p and miR-328-3p,respectively. Here we employed our newly established RNA bioengineering technology to produce bioengineered RNA agents(BERA), namely BERA/miR-27b-3p and BERA/miR-328-3p, via fermentation. When introduced into human cells, BERA/miR-27b-3p and BERA/miR-328-3p were selectively processed to target miRNAs and thus knock down CYP3A4 and ABCG2 mRNA and their protein levels,respectively, as compared to cells treated with vehicle or control RNA. Consequently, BERA/miR-27b-3p led to a lower midazolam 10-hydroxylase activity, indicating the reduction of CYP3A4 activity. Likewise,BERA/miR-328-3p treatment elevated the intracellular accumulation of anticancer drug mitoxantrone, a classic substrate of ABCG2, hence sensitized the cells to chemotherapy. The results indicate that biologic miRNA agents made by RNA biotechnology may be applied to research on miRNA functions in the regulation of drug metabolism and disposition that could provide insights into the development of more effective therapies.
基金supported by National Cancer Institute (R01CA155086)the Wells Center for Pediatric Research, Riley Children Foundation+4 种基金Jeff Gordon Children's FoundationHealthcare Initiatives, Inc.IU Simon Cancer Centerfunded by grants from the National Natural Science foundation of China(Nos. 91529302 and 81472641)Key Projects in the National Science & Technology Pillar Program of China (No. 2014BA109B03)
文摘Gastric cancer is a leading cause of cancer-related mortality worldwide, and options to treat gastric cancer are limited. Fluorouracil （SFu）-based chemotherapy is frequently used as a neoadjuvant or an adjuvant agent for gastric cancer therapy. Most patients with advanced gastric cancer eventually suc- cumb to the disease despite the fact that some patients respond initially to chemotherapy. Thus, iden- tifying molecular mechanisms responsible for chemotherapy resistance will help design novel strategies to treat gastric cancer. In this study, we discovered that residual cancer ceils following 5Fu treatment have elevated expression of hedgehog （Hg） target genes GLII and GLI2, suggestive of Hh signaling activation, Hh signaling, a pathway essential for embryonic development, is an important regulator for putative cancer stem cells/residual cancer cells. We found that high GLI1/GLI2 expression is associated with some features of putative cancer stem cells, such as increased side population. We demonstrated that GLI2 knockdown sensitized gastric cancer cells to 5Fu treatment, decreased ABCG2 expression, and reduced side population. Elevated Gtl2 expression is also associated with an increase in tumor sphere size, another marker for putative cancer stem cells. We believe that GLI2 regulates putative cancer stem cells through direct regulation ofABCG2. ABCG2 can rescue the GLI2 shRNA effects in 5Fu response, tumor sphere formation and side population changes, suggesting that ABCG2 is an important mediator for GLI2- associated 5Fu resistance. The relevance of our studies to gastric cancer patient care is reflected by our discovery that high GLI1/GLI2/ABCG2 expression is associated with a high incidence of cancer relapse in two cohorts of gastric cancer patients who underwent chemotherapy （containing 5Fu）. Taken together, we have identified a molecular mechanism by which gastric cancer cells gain SFu resistance. Copyright 2017, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, a
基金supported by the National Natural Science Foundation of China (No. 81473233)Guangzhou Technology Program Foundation (No. 201604020079)+1 种基金The Science and Technology Project of Guangdong Province (No. 2016A030312014)The Scientific and Technological Leading Talent Project of Guangdong Province (2015)
文摘Overexpressing of ATP-binding cassette(ABC) transporters is the essential cause of multidrug resistance(MDR), which is a significant hurdle to the success of chemotherapy in many cancers.Therefore, inhibiting the activity of ABC transporters may be a logical approach to circumvent MDR.Olmutinib is an epidermal growth factor receptor(EGFR) tyrosine kinase inhibitor(TKI), which has been approved in South Korea for advanced EGFR T790 M-positive non-small cell lung cancer(NSCLC). Here,we found that olmutinib significantly increased the sensitivity of chemotherapy drug in ABCG2-overexpressing cells. Furthermore, olmutinib could also increase the retention of doxorubicin(DOX) and rhodamine 123(Rho 123) in ABC transporter subfamily G member 2(ABCG2)-overexpressing cells. In addition, olmutinib was found to stimulate ATPase activity and inhibit photolabeling of ABCG2 with [^(125) I]-iodoarylazidoprazosin(IAAP). However, olmutinib neither altered ABCG2 expression at protein and m RNA levels nor blocked EGFR, Her-2 downstream signaling of AKT and ERK. Importantly,olmutinib enhanced the efficacy of topotecan on the inhibition of S1-MI-80 cell xenograft growth. All the results suggest that olmutinib reverses ABCG2-mediated MDR by binding to ATP bind site of ABCG2 and increasing intracellular chemotherapeutic drug accumulation. Our findings encouraged to further clinical investigation on combination therapy of olmutinib with conventional chemotherapeutic drugs in ABCG2-overexpressing cancer patients.
文摘目的探讨干细胞标志物三磷酸腺苷结合盒超家族G家族第2个成员(ATP-binding cassette super-family G member 2,ABCG2)在人肝癌细胞株中的表达及其与肝癌耐药的关系,观察人肝癌细胞株中ABCG2阳性表达和阴性表达细胞的功能差异。方法流式细胞仪检测ABCG2在人肝癌细胞株PLC/PRF/5、7402、7701及7721中的阳性表达,计算5-氟尿嘧啶(5-FU)、阿霉素的半数抑制浓度(IC50)值。采用免疫荧光染色观察ABCG2在肝癌7721细胞株中的表达,并进行无菌流式分选,观察ABCG2阳性表达与ABCG2阴性表达的肝癌7721细胞的功能差异。结果在4种肝癌细胞株中7721细胞株ABCG2表达阳性率最高(P<0.05),且流式细胞图中阳性表达和阴性表达细胞呈明显双峰。5-FU、阿霉素对7721细胞株的IC50值明显高于其他3种细胞株,除与5-FU对7701细胞的IC50值差异无统计学意义(P>0.05)外,其余比较差异均有统计学意义(P<0.05)。分选后的ABCG2阳性表达细胞与阴性表达细胞的增殖差异无统计学意义(P>0.05);ABCG2阳性表达细胞较阴性表达细胞更多处于相对静止期(P<0.05)。结论 ABCG2在人多种肝癌细胞株中均表达,ABCG2表达阳性率越高的细胞较表达阳性率越低的细胞更具有耐药性,ABCG2阳性表达细胞处于相对静止期。
基金supported by funds from NIH R15 No. 1R15CA143701 (Z.S. Chen)St.John's University Seed Grant No. 579-1110 (Z.S. Chen)
文摘Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-binding cassette(ABC) transporters,which can increase efflux of drugs from cancer cells,thereby decreasing intracellular drug concentration.Modulators of ABC transporters have the potential to augment the efficacy of anticancer drugs.This editorial highlights some major findings related to ABC transporters and current strategies to overcome MDR.
