Adriamycin In Cells Research Articles

Ginsenoside Rg3 combined with near-infrared photothermal reversal of multidrug resistance in breast cancer MCF-7/ADR cells.

Adriamycin (ADR) is a frequently employed chemotherapeutic agent for the management of breast cancer. Nevertheless, multidrug resistance (MDR) can impair its therapeutic efficacy in breast cancer. MDR is characterized by increased expression of the P-glycoprotein (P-gp) efflux pump, up-regulation of anti-apoptotic proteins, and downregulation of pro-apoptotic proteins. Consequently, inhibition of ATP-binding cassette (ABC) transporter proteins has been deemed the most efficacious approach to overcome MDR. In this study, we used MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide), Western blots, flow cytometry, immunofluorescence, and constructed xenograft tumors to investigate whether ginsenoside Rg3-near-infrared photothermal (Rg3-NIR) combination reversed multidrug resistance in MCF-7/ADR breast cancer. Invivo and invitro experiments, the results showed that Rg3-NIR co-treatment was effective in inducing the apoptosis of MCF-7/ADR breast cancer cells. This was achieved by reversing the expression of drug resistance-associated proteins, while also inhibiting cell proliferation, migration, and epithelial-mesenchymal transition (EMT) processes via attenuation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway transduction. Ginsenoside Rg3 combined with near-infrared photothermal therapy (NIR) effectively reverses multidrug resistance in breast cancer MCF-7/ADR cells, providing a new therapeutic strategy for breast cancer drug resistance.

Metformin alleviates adriamycin resistance of osteosarcoma by declining YY1 to inhibit MDR1 transcriptional activity

Chemotherapy resistance hinders the successful treatment of osteosarcoma (OS) to some extent. Previous studies have confirmed that metformin (Met) enhances apoptosis induced by chemotherapeutic drugs, but the underlying mechanism remains unclear. To establish adriamycin (ADM)-resistant MG-63 (MG-63/ADM) cells, the dosage of ADM was progressively increased. The results of qRT-PCR and Western blotting demonstrated that the expression level of Yin Yang 1 (YY1) and multi-drug resistance-1 (MDR1) in MG-63/ADM cells were remarkably increased compared with those in MG-63 cells. Met dramatically enhanced ADM cytotoxicity and accelerated apoptosis of MG-63/ADM cells. Moreover, Met suppressed the expressions of YY1 and MDR1 in MG-63/ADM cells. YY1 promoted its transcriptional expression by directly binding to the MDR1 promoter. Furthermore, the effects of Met on ADM sensitivity in MG-63/ADM cells was reversed due to overexpression of YY1 or MDR1. Collectively, these findings suggested that Met inhibited YY1/MDR1 pathway to reverse ADM resistance in OS, providing a new insight into the mechanism of Met in ADM resistance of OS.

PLAGL2 increases adriamycin resistance and EMT in breast cancer cells by activating the Wnt pathway.

Adriamycin (ADR) is an effective treatment for breast cancer; nevertheless, it is often linked with acquired resistance in breast cancer cells, reducing ADR's therapeutic efficacy and increasing the risk of recurrence and poor prognosis. It has been revealed that the zinc-finger transcription factor pleomorphic adenoma gene like-2 (PLAGL2) is required for epithelial to mesenchymal transition (EMT) in cancer cells. Recent data indicates that PLAGL2 is also involved in regulating chemotherapeutic drug resistance, albeit the exact mechanism by which this happens remains unknown. This study examines the effect of PLAGL2 on adriamycin resistance and EMT in breast cancer cells. The small interfering RNA (siRNA) targeting PLAGL2 was transfected to breast cancer cells to alter PLAGL2 expression. Cell counting kit-8 (CCK-8) and colony formation assay detected cell growth and proliferation rate. Moreover, wound-healing and transwell assays were conducted to evaluate migration and invasion. Western blot (WB) checked the apoptosis and EMT-associated proteins. PLAGL2 expression is associated with breast cancer cells' acquired resistance to ADR in this investigation. Additionally, deletion of PLAGL2 was associated with enhanced sensitivity to ADR, reduced proliferation, migration, and invasion capabilities, increased E-cadherin levels, and reduced Wnt6, β-catenin, and DVL1 levels in ADR-resistant breast cancer cells (MCF-7/ADR and MDA-MB-231/ADR cells). PLAGL2 could bind to the promoter region of Wnt6 and promote its expression. Additionally, the results of this research established that Wnt signaling is implicated in breast cancer cells' resistance to ADR since BML-284, a Wnt signaling activator partly restored the sensitivity of MCF-7/ADR and MDA-MB-231/ADR cells to ADR. PLAGL2 promotes adriamycin resistance and cell aggressiveness in breast cancer cells via activating the Wnt signaling pathway.

Combination of 7-O-geranylquercetin and microRNA-451 enhances antitumor effect of Adriamycin by reserving P-gp-mediated drug resistance in breast cancer.

Although there are a lot of chemical drugs to treat breast cancer, increasing drug resistance of cancer cells has strongly hindered the effectiveness of chemotherapy. ATP-binding cassette transporters represented by P-glycoprotein (P-gp), multidrug resistance associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) play an important role in drug resistance. This study aims to investigate the effect of 7-O-geranylquercetin (GQ) combining microRNA-451(miR-451) on reversing drug resistance of breast cancer and reveal the mechanism related to P-gp. Real-time RT-PCR and western blot assays showed that miR-326, miR-328, miR-451 and miR-155 inhibitor down-regulated the expression of genes MRP1, BCRP, MDR1 and the corresponding proteins MRP1, BCRP, P-gp, respectively. Cell counting kit-8 (CCK-8) assay indicated that these miRNAs reversed the resistance of MCF-7/ADR cells to Adriamycin (ADR), and miR-451 showed the greatest reversal effect. Combination of GQ and miR-451 enhanced the inhibitory effects of ADR on the proliferation and migration of MCF-7/ADR cells, and attenuated the expression of MDR1 and P-gp in MCF-7/ADR cells. A xenograft tumor model was used to show that GQ and miR-451 amplified the antitumor effect of ADR in nude mice, while western blot and immunohistochemical assays revealed the decreased expression of P-gp in tumor tissues. These results suggest that GQ and miR-451 have synergistic effect on reversing drug resistance through reducing the expression of MDR1 and P-gp in breast cancer MCF-7/ADR cells.

Novel Sigma-2 receptor ligand A011 overcomes MDR in adriamycin-resistant human breast cancer cells by modulating ABCB1 and ABCG2 transporter function.

Multidrug resistance (MDR) is thought to be one of the main reasons for the failure of chemotherapy in cancers. ATP-binding cassette subfamily B member 1 (ABCB1) or P-glycoprotein (P-gp) and ATP-binding cassette subfamily G member 2 (ABCG2) play indispensable roles in cancer cell MDR. Sigma-2 (σ2) receptor is considered to be a cancer biomarker and a potential therapeutic target due to its high expression in various proliferative tumors. Recently, σ2 receptor ligands have been shown to have promising cytotoxic effects against cancer cells and to modulate the activity of P-glycoprotein (ABCB1) in vitro experiments, but their specific effects and mechanisms remain to be elucidated. We found that A011, a σ2 receptor ligand with the structure of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline, showed promising cytotoxicity against breast cancer MCF-7 and adriamycin-resistant MCF-7 (MCF-7/ADR), induced apoptosis, and reversed adriamycin (ADR) and paclitaxel resistance in MCF-7/ADR cells. Furthermore, we demonstrated that A011 increased the accumulation of rhodamine 123 and mitoxantrone in MCF-7/ADR cells. A011 significantly decreased the ATPase activity of the ABCB1 and down-regulated ABCG2 protein expression. In addition, A011, administered alone or in combination with ADR, significantly inhibited tumor growth in the MCF-7/ADR tumor-bearing nude mouse model. A011 may be a potential therapeutic agent for the treatment of tumor resistance.

Gambogenic Acid Inhibits Basal Autophagy of Drug-Resistant Hepatoma Cells and Improves Its Sensitivity to Adriamycin.

Gambogenic acid (GNA) is extracted from plant Gamboge, has a wide range of anti-tumor effects. In this paper, we study the inhibitory effect of GNA on the BEL-7402/ADM of hepatoma resistant cell lines and further study the mechanism of action. Cell viability test represented that GNA could improve the sensitivity of hepatoma drug-resistant cell line BEL-7402/ADM to Adriamycin (ADM), and further study by 4',6-diamidino-2-phenylindole (DAPI) staining and flow cytometry found that GNA could improve the effect of ADM on promoting apoptosis in BEL-7402/ADM cells, and the activation of apoptosis-related protein was significantly increased, and the ratio of Bax to Bcl-2 was significantly increased. Monodansylcadaverine staining and transmission electron microscopy showed that the basal autophagy level of BEL-7402/ADM cells was higher than that of BEL-7402 cells. Further detection of protein expression found that the intracellular LC3-II to LC3-I ratio and Beclin 1 protein expression increased in the combination of GNA and ADM, but the protein level of p62 increased significantly. GNA inhibit protective autophagy in BEL-7402/ADM cells and promote the role of ADM in inducing apoptosis, thereby increasing ADM sensitivity to BEL-7402/ADM cells, and the effect of GNA inhibition of autophagy may be achieved by inhibiting the degradation of autophagosomes.

Circ_0001667 knockdown blocks cancer progression and attenuates adriamycin resistance by depleting NCOA3 via releasing miR-4458 in breast cancer.

Accumulating evidence suggests that developmental chemoresistance in cancers is closely associated with the dysregulation of circular RNA transcriptions. The objective of this study is to disclose the role of circ_0001667 and provide a potential functional mechanism in breast cancer. Quantitative real-time PCR was applied for the analysis of circ_0001667, microRNA-4458 (miR-4458) and nuclear receptor coactivator 3 (NCOA3) expression. In adriamycin (ADM)-resistant cell lines, we investigated cell proliferation using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and colony formation assay. Cell migration and cell invasion were determined by transwell assay. The protein levels of multi-drug resistance-1, matrix metalloproteinases-9, cleaved-caspase3, cleaved-caspase9 and NCOA3 were detected by western blot. ADM resistance was ascertained by IC50 value using MTT assay. Cell apoptosis was checked by flow cytometry assay. The putative relationship between miR-4458 and circ_0001667 and NCOA3 was validated by pull-down assay, dual-luciferase reporter assay or RNA Immunoprecipitation assay. Circ_0001667 knockdown inhibited MCF-7/ADM and MDA-MB-231/ADM cell proliferation, migration, invasion and ADM resistance. MiR-4458 was a target of circ_0001667, and its expression was decreased in ADM-resistant tumor tissues and cells. MiR-4458 inhibition reversed the effects of circ_0001667 knockdown. In depth, NCOA3 was a target of circ_0001667, and circ_0001667 knockdown weakened NCOA3 expression by releasing miR-4458. MCF-7/ADM and MDA-MB-231/ADM cell proliferation, migration, invasion, and ADM resistance inhibited by miR-4458 restoration were recovered by NCOA3 overexpression. Circ_0001667 knockdown also repressed tumor growth and ADM resistance in vivo. Circ_0001667 knockdown blocks cancer progression and attenuates ADM resistance by depleting NCOA3 via releasing miR-4458 in breast cancer.

The effects and mechanisms of aloe‐emodin on reversing adriamycin‐induced resistance of MCF‐7/ADR cells

Multidrug resistance (MDR) is one of the major obstacles for clinical effective chemotherapy. In this study, the effects and possible mechanisms of aloe‐emodin (AE) were investigated on reversing the adriamycin (ADR)‐induced resistance of MCF‐7/ADR cells. AE could significantly reverse the ADR resistance in MCF‐7/ADR cells. The combination of AE (20 μM) and ADR had no effect on the P‐glycoprotein (P‐gp) level, but notably promoted the accumulation of ADR in drug‐resistant cells. The efflux function of P‐gp required ATP, but AE reduced the intracellular ATP level. AE played a reversal role might through inhibiting the efflux function of P‐gp. The research result of energy metabolism pathways indicated that combination of AE and ADR could inhibit glycolysis, tricarboxylic acid (TCA) cycle, glutamine metabolism, and related amino acid synthesis pathways. Moreover, we found AE not only reversed ADR‐induced resistant but also induced autophagy as a defense mechanism. In addition, the combination of AE and ADR arrested G2/M cell cycle and induced apoptosis through DNA damage, ROS generation, caspase‐3 activation. Our study indicated that AE could be a potential reversal agent to resensitize ADR resistant in tumor chemotherapy and inhibiting autophagy might be an effective strategy to further enhance the reversal activity of AE.

Interleukin-6 reverses Adriamycin resistance in nasal NK/T-cell lymphoma via downregulation of ABCC4 and inactivation of the JAK2/STAT3/NF-κB/P65 pathway

Chemotherapy is generally effective for extranodal natural killer (NK)/T-cell lymphoma (ENKTCL), nasal type. Nevertheless, multidrug resistance (MDR) remains a key challenge in treating nasal NK/T-cell lymphoma. Interleukin-6 (IL-6) is reportedly an important regulator of MDR in many cancers, implicating a role of IL-6 in the chemotherapy response. However, the effects and mechanism of IL-6 in nasal NK/T-cell lymphoma remain unclear. Herein, we demonstrated that the IL-6 serum level was decreased in nasal NK/T-cell lymphoma patients compared to chronic rhinitis patients. Lower serum levels of IL-6 were closely correlated with Ki67 expression and patient survival. ATP-binding cassette (ABC) drug transporter ABCC4 in patients was abnormally upregulated. IL-6 significantly inhibited resistance to Adriamycin (ADM) in ADM-resistant SNK-6 cells (SNK-6/ADM). Moreover, IL-6 resulted in cell cycle arrest and led to apoptosis in SNK-6/ADM cells. Furthermore, IL-6 decreased ABCC4, p-JAK2, p-STAT3, and phospho-NF-κB p65 expression in SNK-6/ADM cells. IL-6 in combination with ADM inhibited tumor growth and increased the survival of SNK-6/ADM xenograft mice. In conclusion, our findings suggest that IL-6 can inhibit the upregulation of ABCC4 and inactivate the JAK2/STAT3/NF-κB/P65 pathway to sensitize NK/T-cell lymphoma to ADM, indicating that combination therapy with IL-6 and other chemotherapeutic drugs may be effective in reversing acquired resistance in nasal NK/T-cell lymphoma.

USP37 downregulation elevates the Chemical Sensitivity of Human Breast Cancer Cells to Adriamycin

Background: The evolution of adriamycin (ADR) resistance in the treatment of breast cancer often leads to a poor prognosis in patients. Ubiquitin-specific peptidase 37 (USP37) has been recently identified as a modulator in regulating the stemness of breast cancer cells, but its underlying mechanism remains unclear. In this study, we investigated whether USP37 knockdown could hamper the chemical resistance of MCF-7 and MCF-7/ADR cells to adriamycin and elucidated the potential mechanism.Methods: Immunohistochemistry, western blotting, and RT-qPCR assays were performed to detect the USP37 expression in MCF-7 and MCF-7/ADR cells. The efficiency of USP37 knockdown in breast cancer cells was confirmed by western blotting and RT-qPCR assays. We also performed CCK-8 assay, flow cytometry, western blotting, and TUNEL assays to evaluate cell viability and apoptosis in breast cancer cells. In vivo study was performed to detect the tumorigenicity of MCF-7/ADR cells transfected with shScramble or shUSP37#1 under adriamycin treatment.Results: Bioinformatic analysis indicated that USP37 overexpression was positively correlated with adriamycin resistance. The expression levels of USP37 in both MCF-7 and MCF-7/ADR cells increased significantly with the exposure to adriamycin in a dose-dependent manner. It was verified by the observation that USP37 downregulation elevated the inhibitory effects of adriamycin on breast cancer cells, suppressed cell proliferation caused by cell cycle arrest in G1/S transition, as well as induced apoptosis. Furthermore, in vivo study showed that knockdown of USP37 expression also decreased tumorigenicity of MCF-7/ADR cells in mice. TUNEL assay and observation of cell morphology magnified USP37 knockdown synergized with Adriamycin could elevate the apoptosis of MCF-7 and MCF-7/ADR cells. Western blotting assay illustrated that the combination of USP37 knockdown with adriamycin treatment significantly upregulated the expression levels of cleaved caspase 3 and Bax, whereas the expression level of Bcl-2 was inhibited.Conclusion: Knockdown of USP37 gene expression can reverse the resistance of breast cancer cells to adriamycin, and down-regulating USP37 might be a valuable strategy against ADR resistance in breast cancer therapy.

MiR-765 Regulates Breast Cancer Cell Proliferation, Apoptosis, and Adriamycin Resistance Through Targeting Epithelial Membrane Protein 3

Epithelial membrane protein 3 (EMP3) regulates cell proliferation, differentiation, and apoptosis. Bioinformatics analysis revealed that miR-765 had complimentary sequence with the 3 -URT of EMP3 mRNA. miR-765 regulates EMP3 and influences breast cancer cell behaviors. However, it is unclear whether this regulation plays a role in affecting drug resistance. Our study assessed miR765's role in EMP3 expression and adriamycin (ADM) resistance of breast cancer. ADM resistant cell line MCF-7/ADM was established and assigned into miR-NC group, miR-765 mimic group, siRNA-NC group, and siRNA-EMP3 group followed by analysis of cell proliferation and apoptosis. miR-765 targets EMP3. The miR-765 level and apoptosis rate in MCF-7/ADM cells were significantly lower, while EMP3 level and cell proliferation were higher than MCF-7 cells. miR-765 mimic or siRNA-EMP3 significantly downregulated EMP3, weakened cell proliferation, increased apoptosis, and decreased ADM resistance. MiR-765 and EMP3 involves in ADM resistance of breast cancer cells. Up-regulation of miR-765 inhibits breast cancer cell proliferation and reduces ADM resistance via regulating EMP3.

Exosomal MicroRNA-221-3p Confers Adriamycin Resistance in Breast Cancer Cells by Targeting PIK3R1.

Drug resistance in breast cancer (BC) cells continues to be a stern obstacle hindering BC treatment. Adriamycin (ADR) is a frequently employed chemotherapy agent used to treat BC. The exosomal transfer of microRNAs (miRNAs) has been reported to enhance the drug-resistance of BC cells. Herein, we first sought to elucidate the possible role of the exosomal transfer of miR-221-3p in the drug resistance of MCF-7 cells to ADR. Differentially expressed genes (DEGs) were initially screened through microarray analysis in BC drug resistance-related datasets. Next, the expression of miR-221-3p and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was quantified in ADR-resistant MCF-7 (MCF-7/ADR) and ADR-sensitive MCF-7 (MCF-7/S) cell lines, after which exosomes were separated and identified in each cell line. Target relationship between miR-221-3p and PIK3R1 was validated by a dual-luciferase reporter assay. Next, the expression of miR-221-3p and PIK3R1 was altered to clarify their effects on the resistance of MCF-7 cells to ADR in vitro and in vivo. PIK3R1 was identified as a BC drug resistance-related DEG, with the regulatory miR-221-3p subsequently obtained. Moreover, the MCF-7/ADR cells exhibited a low expression of PIK3R1 and a high expression of miR-221-3p. Notably, PIK3R1 was identified as a target gene of miR-221-3p. The overexpression of miR-221-3p in MCF-7/ADR cell-derived exosomes promoted ADR resistance in MCF-7/S cells via the PI3K/AKT signaling pathway. The in vitro results were reproducible in in vivo assays. Taken together, drug-resistant BC cell-derived exosomal miR-221-3p can promote the resistance of BC cells to ADR by targeting PIK3R1 via the PI3K/AKT signaling pathway in vitro and in vivo. These findings provide encouraging insights and provide perspectives for further investigation into the BC drug resistance mechanism.

MiR-506 Affects Cervical Cancer Cell Resistance to Adriamycin (ADM) Through Regulating Signal Transducer and Activator of Transcription 3 (STAT3)

STAT3 is involved in the development and resistance of several tumors. Abnormal miR-506 expression is associated with cervical cancer. miR-506 was predicted to have a relationship with STAT3. Our study investigated miR-506's role in cervical cancer cell adriamycin (ADM) resistance. The ADM drug-resistant cell line, Caski/ADM was established followed by measuring miR-506 and STAT3 mRNA level by qRT-PCR and STAT3 protein expression by Western blot. The Caski/ADM cells were separated into miR-NC group and miR-506 mimic group followed by analysis of STAT3 and p-STAT3 level by Western blot, cell apoptosis and proliferation by flow cytometry. There was a targeted regulatory relationship between miR-506 and STAT3 mRNA. miR-506 in Caski/ADM cells was significantly downregulated compared to that in Caski cells, which further significantly reduced compared to HCerEpiC cells. Caski/ADM cells had highest STAT3 level followed by Caski cells and HCerEpiC cells. miR-506 mimic transfection significantly upregulated miR-506, decreased STAT3 and p-STAT3 level with increased cell apoptosis and decreased cell proliferation as well as resistance. miR-506 level regulates cervical cancer ADM resistance. Increasing miR-506 expression down-regulates STAT3 expression, inhibits proliferation of cervical cancer cells, promotes apoptosis and reduces ADM resistance.

Isolation and Biological Characterization of Lung Cancer Stem Cells

Objective To explore the methods of screening and biological characteristics of lung cancer stem cells. Methods We selected the ABCG2 +and ABCG2 -cells from SPC-A-1/adriamycin(ADM)cell line induced by ADM and analyzed the tumorigenicity of ABCG2 +and ABCG2 -cells in vivo by flow cytometry and transplantation in nude mice. Results The average fluorescence intensity of SPC-A-1 cells was(1.001±0.014)×10 2,which was significantly lower than that of SPC-A-1/ADM cells [(10.257±0.023) ×10 2 ](t=17.320,P=0.001);the difference was also statistically significant between the ABCG2/BCRP-FITC treatment group and the SPC-A-1 control group(t=5.269,P=0.021) and the SPC-A-1 control group(t=6.869, P=0.012) and between the SPC-A-1/ADM cell control group and the SPC-A-1/ADM cell homotype control group(t=8.112,P=0.015).The positive rate of SPC-A-1/ADM cells treated with ABCG2/BCRP-FITC was 9.8%,39.84 times higher than that of SPC-A-1 cells;it showed significant difference between the ABCG2/BCRP-FITC group and the SPC-A-1/ADM group(t=9.120,P=0.005) and the SPC-A-1/ADM group(t=8.257,P= 0.006).The positive rate of group B cells was 684 times that of group A cells,and the difference was statistically significant(t=11.235,P=0.001),and the fluorescence intensity of group B cells was strong.The average tumorigenic volume of the mice inoculated with SPC-A-1 cells,group A cells,and group B cells was(6.96±1.82),(6.70±2.55),and(9.17±2.41) mm 3,respectively.Among them,group B was the highest,but there was no significant difference among these three groups(F=2.362,P=0.086).The tumorigenic rate of group B cells was 75.00%,which was significantly higher than that of SPC-A-1 cells and group A cells(F=19.780,P=0.002). Conclusion ABCG2 cells from human lung adenocarcinoma SPC-A-1/ADM cell line can be isolated by ABCG2 antibody combined with immunomagnetic beads sorting method,and the tumor formation rate in nude mice can be observed to explore the identification and biological characterization of lung cancer stem cells.

Abstract P6-03-19: Oridonalogs reverse chemoresistance in breast cancer cells by targeting STAT3

Abstract Chemotherapy remains the mainstream treatment option for invasive and metastatic breast cancer. Adriamycin (ADR) is one of the most frequently used and an effective chemotherapeutic agent for treating patients with breast cancer. However, the resistance towards ADR becomes a major obstacle to achieve efficacy and favorable outcomes in breast cancer patients with chemotherapy. We recently developed a serial oridonalogs that may possess the ability to overcome chemoresistance in cancer cells, whereas whether these novel anti-cancer agents reverse ADR resistance in resistant breast cancer cells are not adequately explored and further the mechanism of action has not been studied. In this study, oridonalogs, YD0514, CYD0618, and CYD0686, were used to determine their effects on the proliferation of the ADR-resistant breast cancer cells. We found significant inhibition of proliferation of wild-type breast cancer cell line MCF-7 and ADR-resistant MCF-7/ADR cells, time- and dose-dependently. Among the tested compounds, CYD0618 and CYD0686 were more effective in inducing apoptosis in wild-type and resistant breast cancer cells than YD0514, in comparison to the natural product and lead compound oridonin. In addition, total STAT3 level was found higher in ADR-resistant breast cancer cells, while phospho-STAT3 was higher in resistant cells. CYD0618 inhibited STAT3 activation in ADR-resistant cells. Our findings suggest that STAT3 activation may be critically involved in the development of acquired resistance to ADR, while oridonalogs such as CYD0618 may open the avenue to reverse and overcome ADR resistance in breast cancer by targeting STAT3. Further mechanistic explorations are currently underway. Citation Format: Xi Liu, Yefei Wen, Hyejin Kim, Pingyuan Wang, Haiying Chen, Mingdao Hu, Ye Ding, Jia Zhou, Qiang Shen. Oridonalogs reverse chemoresistance in breast cancer cells by targeting STAT3 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-03-19.

The lncRNA-GAS5/miR-221-3p/DKK2 Axis Modulates ABCB1-Mediated Adriamycin Resistance of Breast Cancer via the Wnt/β-Catenin Signaling Pathway

Drug resistance, including adriamycin (ADR)-based therapeutic resistance, is a crucial cause of chemotherapy failure in breast cancer treatment. Acquired chemoresistance has been identified to be closely associated with the overexpression of P-glycoprotein (P-gp/ABCB1). Long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) can be involved in carcinogenesis; however, its roles in ABCB1-mediated ADR resistance are poorly understood. In this study, we identified a panel of differentially expressed lncRNAs, mRNAs, and microRNAs (miRNAs) in MCF-7 and MCF-7/ADR cell lines through RNA sequencing (RNA-seq) technologies. GAS5 level was downregulated whereas ABCB1 level was upregulated in the resistant breast cancer tissues and cells. Overexpression of GAS5 significantly enhanced the ADR sensitivity and apoptosis, and it inhibited the efflux function and expression of ABCB1 in vitro, while knockdown of GAS5 had the opposite effects. Further mechanism-related investigations indicated that GAS5 acted as an endogenous “sponge” by competing for miR-221-3p binding to regulate its target dickkopf 2 (DKK2), and then it inhibited the activation of the Wnt/β-catenin pathway. Functionally, GAS5 enhanced the anti-tumor effect of ADR in vivo. Collectively, our findings reveal that GAS5 exerted regulatory function in ADR resistance possibly through the miR-221-3p/DKK2 axis, providing a novel approach to develop promising therapeutic strategy for overcoming chemoresistance in breast cancer patients.

Grape seed proanthocyanidin extract reverses multidrug resistance in HL-60/ADR cells via inhibition of the PI3K/Akt signaling pathway

Background and purposeMultidrug resistance (MDR) is a great challenge and obstacle in cancer treatment. It is a common problem in the treatment of acute myeloid leukemia (AML). Whether grape seed proanthocyanidin extract (GSPE) could reverse MDR in patients with AML is still unknown. The aim of this study was to investigate the MDR reverse ability of GSPE and its possible mechanism in vitro. Materials and methodsHuman leukemia cell line HL-60 cells and HL-ADR cells were used. MTT assay were employed to identify the cytotoxic effects of different chemotherapeutic drugs and reverse ability of GSPE. Flow cytometry assays were used to verify the cell apoptosis induced by GSPE. MDR-related genes expression was tested by real-time polymerase chain reaction (Q-PCR). MDR-related protein expression was assessed by Western blotting assays. The genes and their related protein expression of multidrug resistance-associated protein 1 (MRP1), multidrug resistance protein 1 (MDR1) and lung resistance-related protein (LRP) were tested in this study. Key resultsWe found that HL-60/ADR cells were resistant to a variety of chemotherapeutic drugs, including cytarabine (Ara-C), adriamycin (ADR), vincristine (VCR), daunorubicin (DNR), mitoxantrone (MTZ), pirarubicin (THP), homoharringtonine (HHT) and etoposide (VP16). Co-treatment with GSPE could significant lower the IC50 of Ara-C and ADR in HL-60/ADR cells (P < 0.01). MDR related mRNA and their protein expression of MRP1 and MDR1 were significant highly expressed in HL-60/ADR cells than HL-60 cells (P < 0.01). But only protein expression of LRP was higher in HL-60/ADR cells than HL-60 cells (P < 0.05). GSPE could induce a higher intracellular level of ADR in HL-60/ADR cells. It could also inhibit Akt phosphorylation resulted in the down regulation of MRP1, MDR1 and LRP and induce cell apoptosis. 25.0 μg/mL GSPE significant inhibited the Akt phosphorylation (P < 0.05). Conclusion and implicationsGSPE-reversed MDR of HL-60/ADR cells might be associated with the inhibition of the PI3K/Akt signaling pathway, which resulted in the down-regulation the expression of MRP1, MDR1 and LRP. These results provide that GSPE may serve as a combination therapy in AML chemotherapy for future study.

Shenmai injection suppresses multidrug resistance in MCF-7/ADR cells through the MAPK/NF-κB signalling pathway

Context Shenmai Injection (SMI) is usually used to treat atherosclerotic coronary heart disease and viral myocarditis in China. However, the effect of SMI on multidrug resistance has not been reported. Objective To investigate the reversal effect of SMI in adriamycin (ADR) resistant breast cancer cell line (MCF-7/ADR) and explore the related molecular mechanisms. Materials and methods The effect of SMI (0.25, 0.5, 1 mg/mL) to reverse chemoresistance in MCF-7/ADR cells was elucidated by MTT, HPLC-FLD, DAPI staining, flow cytometric analysis, western blotting. At the same time, in vivo test was conducted to probe into the effect of SMI on reversing ADR resistance, and verapamil (10 μM) was used as a positive control. Results The results showed that the toxicity of ADR to MCF-7/ADR cells was strengthened significantly after treated with SMI (0.25, 0.5, 1 mg/mL), the IC50 of ADR was decreased 54.4-fold. The intracellular concentrations of ADR were increased 2.2-fold (p < 0.05) and ADR accumulation was enhanced in the nuclei (p < 0.05). SMI could strongly enhance the ADR-induced apoptosis and increase intracellular rhodamine 123 accumulation in MCF-7/ADR cells. Additionally, a combination of ADR and SMI (5 mg/kg) could dramatically reduce the weight and volume of tumour (p < 0.05). Furthermore, the results revealed that SMI might reverse MDR via inhibiting ADR-induced activation of the mitogen-activated protein kinase/nuclear factor (NF)-κB pathway to down-regulated the expression of P-glycoprotein (P-gp). Discussion and conclusions SMI could potentially be used to treat ADR-resistance. This suggests possibilities for future clinical research.

LncRNA KCNQ1OT1 contributes to the progression and chemoresistance in acute myeloid leukemia by modulating Tspan3 through suppressing miR-193a-3p

AimsAcute myeloid leukemia (AML) is an aggressive cancer that invariably produces drug resistance after treatment. The aim is to explore the role of lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) and associated novel mechanisms in the progression and chemoresistance of AML. Main methodsThe expression of KCNQ1OT1, miR-193a-3p, and Tspan3 was measured by qRT-PCR. The values of IC50 for adriamycin (ADR) and the ability of proliferation were analyzed by CCK-8 assay. Cell migration and invasion were assessed by transwell assay. Cell apoptosis was monitored by flow cytometry assay. The expression of Tspan3, MRP1, P-gp and LRP at the protein level was quantified by western blot. The relationship between miR-193a-3p and KCNQ1OT1 or Tspan3 was predicted by bioinformatics tool Diana and verified by dual-luciferase reporter assay, RIP assay or RNA pull-down assay. Key findingsKCNQ1OT1 and Tspan3 were up-regulated, while miR-193a-3p was down-regulated in ADR resistant AML samples and cells. KCNQ1OT1 knockdown reduced ADR resistance, inhibited proliferation, migration and invasion but promoted apoptosis of ADR resistant AML cells, miR-193a-3p inhibition reversed these effects. MiR-193a-3p was a target of KCNQ1OT1 and combined with Tspan3 3′ untranslated region (3′ UTR). Enrichment of miR-193a-3p decreased ADR resistance, inhibited proliferation, migration and invasion and stimulated apoptosis in ADR resistant AML cells, but Tspan3 overexpression overturned these impacts. SignificanceKCNQ1OT1 aggravates AML progression and chemoresistance to ADR by inducing Tspan3 expression via adsorbing miR-193a-3p in ADR resistant AML cells, providing a theoretical basis for the treatment of AML with chemoresistance.

7-O-geranylquercetin contributes to reverse P-gp-mediated adriamycin resistance in breast cancer

AimsTo investigate the effect of 7-O-geranylquercetin (GQ), a derivative of quercetin (Q), on reversing drug resistance in breast cancer MCF-7/ADR cells and reveal the mechanisms related to P-glycoprotein (P-gp). Main methodsCell viability was determined by MTT assay. Accumulation of adriamycin (ADR) in cells was determined by confocal fluorescence microscope and microplate reader while that of rhodamine (Rh) was measured by flow cytometry. Expression levels of P-gp and MDR1 gene in cells were detected by western blot and Real-Time PCR, respectively. Molecular docking of GQ and Q with P-gp was conducted using AutoDock program. Xenograft model was established by inoculating MCF-7/ADR cells in BALB/c-nude mice. Tumor bearing mice were administered with ADR via tail vein injection and/or GQ (Q) by gavage. Expression levels of P-gp in tissues were detected by western blot and immunohistochemistry. Key findingsGQ could reverse drug resistance of MCF-7/ADR cells to ADR. GQ inhibited the efflux of ADR by down-regulating the expression of P-gp protein and its encoding gene MDR1 in MCF-7/ADR cells. Molecular modeling showed that GQ matched with P-gp better than Q. GQ enhanced the antitumor effects of ADR and decreased the expression of P-gp in mice and its activities were higher than that of Q. GQ could reverse drug resistance of MCF-7/ADR cells by down-regulating the expression of P-gp in vitro and in vivo. SignificancesThe reversal effect of GQ on P-gp-mediated drug resistance indicates its potential as a reversal agent for drug resistance in cancer chemotherapy.