Doxorubicin-resistant Breast Cancer Cells Research Articles

Extracellular vesicles from human breast cancer-resistant cells promote acquired drug resistance and pro-inflammatory macrophage response.

Breast cancer is a significant public health problem around the world, ranking first in deaths due to cancer in females. The therapy to fight breast cancer involves different methods, including conventional chemotherapy. However, the acquired resistance that tumors develop during the treatment is still a central cause of cancer-associated deaths. One mechanism that induces drug resistance is cell communication via extracellular vesicles (EVs), which can carry efflux transporters and miRNA that increase sensitive cells' survivability to chemotherapy. Our study investigates the transcription changes modulated by EVs from tamoxifen- and doxorubicin-resistant breast cancer cells in sensitive cells and how these changes may induce acquired drug resistance, inhibit apoptosis, and increase survivability in the sensitive cells. Additionally, we exposed human macrophages to resistant EVs to understand the influence of EVs on immune responses. Our results suggest that the acquired drug resistance is associated with the ability of resistant EVs to upregulate several transporter classes, which are directly related to the increase of cell viability and survival of sensitive cells exposed to EVs before a low-dose drug treatment. In addition, we show evidence that resistant EVs may downregulate immune system factors to evade detection and block cell death by apoptosis in sensitive breast cancer cells. Our data also reveals that human macrophages in contact with resistant EVs trigger a pro-inflammatory cytokine secretion profile, an effect that may be helpful for future immunotherapy studies. These findings are the first transcriptome-wide analysis of cells exposed to resistant EVs, supporting that resistant EVs are associated with the acquired drug resistance process during chemotherapy by modulating different aspects of sensitive cancer cells that coffer the chemoresistance.

LINC00460-FUS-MYC feedback loop drives breast cancer metastasis and doxorubicin resistance.

Therapeutic resistance and metastasis largely contribute to mortality from breast cancer and therefore understanding the underlying mechanisms of such remains an urgent challenge. By cross-analysis of TCGA and GEO databases, LINC00460 was identified as an oncogenic long non-coding RNA, highly expressed in Doxorubicin resistant breast cancer. LINC00460 was further demonstrated to promote stem cell-like and epithelial-mesenchymal transition (EMT) characteristics in breast cancer cells. LINC00460 interacts with FUS protein with consequent enhanced stabilization, which further promotes MYC mRNA maturation. LINC00460 expression was transcriptionally enhanced by c-MYC protein, forming a positive feedback loop to promote metastasis and Doxorubicin resistance. LINC00460 depletion in Doxorubicin-resistant breast cancer cells restored sensitivity to Doxorubicin and increased the efficacy of c-MYC inhibitor therapy. Collectively, these findings implicate LINC00460 as a promising prognostic biomarker and potential therapeutic target to overcome Doxorubicin resistance in breast cancer.

Efficient separation of large particles and giant cancer cells using an isosceles trapezoidal spiral microchannel.

Polyploid giant cancer cells (PGCCs) contribute to the genetic heterogeneity and evolutionary dynamics of tumors. Their size, however, complicates their isolation from mainstream tumor cell populations. Standard techniques like fluorescence-activated cell sorting (FACS) rely on fluorescent labeling, introducing potential challenges in subsequent PGCC analyses. In response, we developed the Isosceles Trapezoidal Spiral Microchannel (ITSμC), a microfluidic device optimizing the Dean drag force (FD) and exploiting uniform vortices for enhanced separation. Numerical simulations highlighted ITSμC's advantage in producing robust FD compared to rectangular and standard trapezoidal channels. Empirical results confirmed its ability to segregate larger polystyrene (PS) particles (avg. diameter: 50 μm) toward the inner wall, while directing smaller ones (avg. diameter: 23 μm) outward. Utilizing ITSμC, we efficiently isolated PGCCs from doxorubicin-resistant triple-negative breast cancer (DOXR-TNBC) and patient-derived cancer (PDC) cells, achieving outstanding purity, yield, and viability rates (all greater than 90%). This precision was accomplished without fluorescent markers, and the versatility of ITSμC suggests its potential in differentiating a wide range of heterogeneous cell populations.

Chemical Analysis of Ethanolic Extract of Ripe Fruit, N-Hexane Fraction of Half-Ripe Fruit, and Water Fraction of Half-Ripe Fruit of Sesoot (Garcinia Picrorrhiza Miq.) with Liquid Chromatography-Mass Spectrometry (Lc-Ms)

Garcinia is a plant belonging to the family of Guttiferae or Cluciaceae and has more than 180 famous species. Most of Garcinia species contains many prenelated xanthones, biflavonoids, and benzophenones. Using Liquid Chromatography - Mass Spectrometry (LC-MS), the development of electrospray ionization (ESI) could be detected and could be applied to a wide range of molecular biology such as xanthones, biflavonoids, and benzophenones and their derivatives. This method with a high speed of scanning at once could be measured a high degree of multiplexing and many components can be measured with a single analysis. These results were separated and analyzed using literature software of Dictionary of Natural Product 2006. The ethanolic extract of ripe fruit (IC), the n-hexane fraction of half ripe (IIB), and the water fraction of half ripe fruit (IVB) of sesoot (G. picrorrhiza Miq.) showed that the major compounds of them were xanthones, benzophenones with their derivatives, furanone and pyranone which were proven as cytotoxic to the brine shrimp nauplii using Brine Shrimp Lethality Test (BSLT) and to the doxorubicin-resistant breast cancer cell line of MCF-7, the doxorubicin-sensitive breast cancer cell line of T47D.

Jatrophone: a cytotoxic macrocylic diterpene targeting PI3K/AKT/NF-κB pathway, inducing apoptosis and autophagy in resistant breast cancer cells

BackgroundBreast cancer is a prevalent malignant tumor that affects women worldwide. The primary challenge in treating breast cancer is combating drug resistance, which contributes to relapse and metastasis. Jatrophone is a unique macrocyclic jatrophane diterpene found in various Jatropha and Euphorbia species. It possesses diverse biological and pharmacological activities, including anticancer activity. However, it is unclear whether jatrophone can overcome drug resistance in breast cancer.MethodsThis study includes the investigation of the cytotoxicity of jatrophone on doxorubicin-resistant breast cancer cells (MCF-7ADR) and the underlying molecular mechanisms. The effects of jatrophone on cell viability were determined using the sulforhodamine B (SRB) assay, while flow cytometry was used to evaluate cell cycle progression, apoptosis, and autophagy. A scratch assay was conducted to observe cell migration, and western blotting was used to measure downstream protein levels (PI3K, AKT, and NF-κB). Unpaired Student’s t-tests were used for comparison between the two groups and the results were analyzed by one-way ANOVA with Tukey- Kremer post hoc test.ResultsIt was shown that jatrophone exhibited potent cytotoxic activity on MCF-7ADR cells in a dose-dependent manner, with an IC50 value of 1.8 µM. It also significantly induced cell cycle S and G/M phase arrest. Interestingly, jatrophone induced both early and late apoptotic cell death, as well as autophagic cell death, with negligible necrosis. Furthermore, jatrophone treatment diminished the migration of MCF-7ADR cells. At the molecular level, jatrophone treatment significantly down-regulated the expression levels of PI3K, AKT, and NF-κB. β.ConclusionsThe results of the study suggest that jatrophone decreases the proliferation of MCF-7/ADR cells at a low micromolar concentration; induces cell cycle arrest; promotes apoptotic, and autophagic cell death; inhibits migration and EMT; and works on resistance by a mechanism involving the inhibition of the PI3K/Akt/ NF-κB pathway. These findings provide evidence of the potential of jatrophone to be a promising lead compound for targeting doxorubicin-resistant breast cancer cells and could be further investigated for its clinical application as a chemotherapy adjuvant.

Combined doxorubicin and arctigenin treatment induce cell cycle arrest-associated cell death by promoting doxorubicin uptake in doxorubicin-resistant breast cancer cells.

Chemotherapy failure is often caused by drug resistance, for which no effective treatment strategy has been established. Many studies have been undertaken with the aim of overcoming drug resistance using natural products. Arctigenin (ATG), a natural product, has been investigated for its anti-cancer effects in HER2-overexpressing, ER-positive, and triple-negative breast cancer cells. We investigated the efficacy of ATG against self-established doxorubicin (DOX)-resistant breast cancer cells (MCF-DR and MDA-DR cells) derived from MCF-7 and MDA-MB-231 cells, respectively. ATG was found to increase DOX intracellular levels by downregulating multidrug Resistance 1 (MDR1) mRNA expression in DOX-resistant cells. In addition, combined treatment with DOX and ATG (DOX/ATG) reduced the viability of and colony formation by DOX-resistant cells. DOX/ATG also significantly induced G2/M cell cycle arrest by suppressing the Cyclin D1/CDK4/RB pathways and suppressed the expressions of MDR1 and Cyclin D1 by inhibiting the Mitogen-activated protein kinase (MAPK)/Activating protein-1 (AP-1) signaling pathways. Furthermore, DOX/ATG induced DNA damage and attenuated the expressions of RAD51 and Ku80. However, PARP1 (Poly [ADP-ribose] polymerase1) cleavage and AIF (Apoptosis-inducing factor) induced apoptosis did not occur despite DNA damage-induced cell death. Rather, flow cytometry showed that DOX/ATG caused necrosis. In summary, DOX/ATG increased intracellular DOX levels by inhibiting MDR1 and inducing G2/M arrest by inhibiting the Cyclin D1/CDK4/RB pathways and causing necrosis by damaging DNA. Our results suggest that ATG might be used as an adjuvant to enhance the efficacy of DOX in DOX-resistant breast cancer.

Reversal Effect of Saikosaponin A and Saikosaponin B on Doxorubicin-resistant Breast Cancer Cells and its Mechanism

Background One of the key factors limiting the effectiveness of chemotherapy treatment for malignancies is multidrug resistance (MDR). The MDR phenotype is related to P-glycoprotein (P-gp) expression and function. The main triterpenoid saponins generated from Bupleurum chinense DC (BCDC), saikosaponin A (SSa), has been found to have anti-tumor potential. Saikosaponin B (SSb) has the potential for utility in combination with anticancer drugs as the secondary saikosaponins. Objective In this study, we looked into the impact of SSa and SSb on doxorubicin (Dox)-resistant breast cancer cells and its underlying mechanisms. Materials and Methods Dox-resistant breast cancer cells (MCF-7ADR) and MCF-7 cells were used in the study. The experimental cells were divided into a different concentration SSa administration group, a different concentration SSb administration group, and a control group, and the related biochemical parameters of MCF-7 and MCF-7ADR cells were detected. Results We discovered that SSa and SSb both suppressed MCF-7 and MCF-7ADR cell proliferation in a dose-dependent manner. Additionally, SSa at 2.5 and 5.0 µg/mL and SSb at 3.0 and 7.0 µg/mL could significantly enhance the cytotoxicity of Dox and reverse MDR in MCF-7ADR cells. The combination of Dox and SSa or SSb induced obvious synergistic effects. SSa and SSb could increase the sensitivity of MCF-7ADR cells to Dox by decreasing P-gp expression, increasing intracellular accumulation, and delaying the drug efflux of rhodamine 123 (Rh123, a P-gp substrate). Additionally, SSa and SSb both induced G1-phase arrest in MCF-7ADR cells in the presence of Dox. Conclusion According to the study, SSa and SSb may be novel MDR reversal medicines for breast cancer chemotherapy and have significant therapeutic significance for MDR during tumor therapy.

Cytotoxic and chemomodulatory effects of Phyllanthus niruri in MCF-7 and MCF-7ADR breast cancer cells

The members of the genus Phyllanthus have long been used in the treatment of a broad spectrum of diseases. They exhibited antiproliferative activity against various human cancer cell lines. Breast cancer is the most diagnosed cancer and a leading cause of cancer death among women. Doxorubicin (DOX) is an anticancer agent used to treat breast cancer despite its significant cardiotoxicity along with resistance development. Therefore, this study was designed to assess the potential cytotoxicity of P. niruri extracts (and fractions) alone and in combination with DOX against naïve (MCF-7) and doxorubicin-resistant breast cancer cell lines (MCF-7ADR). The methylene chloride fraction (CH2Cl2) showed the most cytotoxic activity among all tested fractions. Interestingly, the CH2Cl2-fraction was more cytotoxic against MCF-7ADR than MCF-7 at 100 µg/mL. At sub-cytotoxic concentrations, this fraction enhanced the cytotoxic effect of DOX against the both cell lines under investigation (IC50 values of 0.054 µg/mL and 0.14 µg/mL vs. 0.2 µg/mL for DOX alone against MCF-7) and (1.2 µg/mL and 0.23 µg/mL vs. 9.9 µg/mL for DOX alone against MCF-7ADR), respectively. Further, TLC fractionation showed that B2 subfraction in equitoxic combination with DOX exerted a powerful synergism (IC50 values of 0.03 µg/mL vs. 9.9 µg/mL for DOX alone) within MCF-7ADR. Untargeted metabolite profiling of the crude methanolic extract (MeOH) and CH2Cl2 fraction exhibiting potential cytotoxicity was conducted using liquid chromatography diode array detector-quadrupole time-of-flight mass spectrometry (LC-DAD-QTOF). Further studies are needed to separate the active compounds from the CH2Cl2 fraction and elucidate their mechanism(s) of action.

Cancer Cells and Platelets Have a Synergistic Role on the Acceleration of Clot Formation and Fibrin Polymerization. a Thromboelastometric Study

Introduction The histological type and the aggressiveness of cancer cells as well as the acquisition of resistance to chemotherapy are significant predictors for the high risk of cancer associated thrombosis (CAT). It is well established that cancer cells, by expressing tissue factor (TF) trigger thrombin generation. Cancer cell derived extracellular vesicles (CaCa-dEV) bearing TF, in the microenvironment, further enhance thrombin generation. The impact of cancer cells on clot formation kinetics and the qualitative characteristics of the clot has not been evaluated yet. Aim The present study aimed to analyze the variables which influence the kinetics and the qualitative characteristics of the clot after triggering thrombin generation by cells from pancreatic cancer (BXPC3), breast cancer (MCF7 and MCF7R10) and multiple myeloma (RPMI-8226 and U266) - associated with different risk of CAT. The impact of the resistance to chemotherapy on the clot characteristics was also studied. Methods Cancer cell lines (BXPC3, MCF7, MCF7R10, RPMI-8226 and U266) and primary umbilical vein endothelial cells (HUVEC) for the control experiments were used according to standardized and validated experimental procedure. Doxorubicin resistant breast cancer cells (MCF7R10) were obtained by treating native breast cancer cells (MCF7) by increasing concentrations of Doxorubicin from 5 nM to 10 µM.. Thromboelastometry, using the ROTEM® delta device (from Warfen Paris, France), was used for the study of clot formation and firmness in whole blood (WB), platelet rich and platelet poor plasma (PRP and PPP respectively) in the presence of cancer cells or HUVEC (control). A suspension of 200 μL with 105 cells was placed in each sterilized cup. Following an incubation of 4 hour, culture media was removed and 330 μL of WB, PRP or PPP were added followed by addition of 20 µM of CaCl2 (0.2 M). Clotting time (CT), α-angle and maximum clot firmness (MCF) were analyzed. Results In PPP, pancreatic cancer cells BXPC3 as well as chemotherapy sensitive and resistant breast cancer cells (MCF7 and MCF7R10), significantly reduced the CT. MCF7R10 cells significantly reduced the CT as compared to MCF7. In contrast, myeloma cells (RPMI8226 and U266), did not significantly affect the CT. All studied cancer cell lines significantly increased the α-angle as compared to HUVEC, with the most potent effect from BXPC3 cells. The studied cancer cell lines did not significantly affect MCF. In PRP, BXPC3 cells significantly reduced the CT whereas MCF7 and MCF7R10 did not significantly change the CT, and myeloma cells significantly prolonged the CT as compared to HUVEC. BXPC3 cells significantly increased the α-angle as compared to the HUVEC, whereas the other studied cancer cell lines did not have any significant effect on this parameter. BXPC3, MCF7 and MCF7R10 cells did not significantly affect the MCF whereas the myeloma cells significantly decreased the MCF as compared to HUVEC. In WB, BXPC3 and MCF7 cells significantly decreased the CT whereas MCF7R10 did not show any significant effect and the myeloma cells significantly prolonged it. The α-angle significantly increased in the presence of BXPC3 cells whereas the other cell lines did not show any significant effect on this parameter. The presence of cancer cells resulted in significant decrease of the MCF as compared to the control (HUVEC), with the most potent effect from myeloma. In the control experiment (HUVEC), the comparison of the thromboelastometric profile of the three experimental systems (PPP, PRP and WB) showed that platelets (PRP) had a substantial impact on CT, α-angle and MCF whereas the erythrocytes (in WB) did not further modify these parameters. The same pattern of the role of platelets was observed in the presence of the studied cancer cell lines. Discussion The present study provides experimental evidence documenting that cancer cells impact clot formation kinetics without affecting clot firmness. The impact of cancer cells on clot formation kinetics is determined principally by the histological type. The pancreatic adenocarcinoma cells have a more pronounced effect on clot formation kinetics as compared to the breast cancer cells (sensitive or resistant to Doxorubicine). In contrast, multiple myeloma cells delay fibrin formation and polymerization and decrease the clot firmness. Platelets have a synergistic effect with cancer cells on the acceleration of the clot formation kinetics. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

CircRNA-CREIT inhibits stress granule assembly and overcomes doxorubicin resistance in TNBC by destabilizing PKR

BackgroundCircular RNAs (circRNAs) represent a novel type of regulatory RNA characterized by high evolutionary conservation and stability. CircRNAs are expected to be potential diagnostic biomarkers and therapeutic targets for a variety of malignancies. However, the regulatory functions and underlying mechanisms of circRNAs in triple-negative breast cancer (TNBC) are largely unknown.MethodsBy using RNA high-throughput sequencing technology, qRT-PCR and in situ hybridization assays, we screened dysregulated circRNAs in breast cancer and TNBC tissues. Then in vitro assays, animal models and patient-derived organoids (PDOs) were utilized to explore the roles of the candidate circRNA in TNBC. To investigate the underlying mechanisms, RNA pull-down, RNA immunoprecipitation (RIP), co immunoprecipitation (co-IP) and Western blotting assays were carried out.ResultsIn this study, we demonstrated that circRNA-CREIT was aberrantly downregulated in doxorubicin resistant triple-negative breast cancer (TNBC) cells and associated with a poor prognosis. The RNA binding protein DHX9 was responsible for the reduction in circRNA-CREIT by interacting with the flanking inverted repeat Alu (IRAlu) sequences and inhibiting back-splicing. By utilizing in vitro assays, animal models and patient-derived organoids, we revealed that circRNA-CREIT overexpression significantly enhanced the doxorubicin sensitivity of TNBC cells. Mechanistically, circRNA-CREIT acted as a scaffold to facilitate the interaction between PKR and the E3 ligase HACE1 and promoted proteasomal degradation of PKR protein via K48-linked polyubiquitylation. A reduced PKR/eIF2α signaling axis was identified as a critical downstream effector of circRNA-CREIT, which attenuated the assembly of stress granules (SGs) to activate the RACK1/MTK1 apoptosis signaling pathway. Further investigations revealed that a combination of the SG inhibitor ISRIB and doxorubicin synergistically inhibited TNBC tumor growth. Besides, circRNA-CREIT could be packaged into exosomes and disseminate doxorubicin sensitivity among TNBC cells.ConclusionsOur study demonstrated that targeting circRNA-CREIT and SGs could serve as promising therapeutic strategies against TNBC chemoresistance.

Reorganization of 3D chromatin architecture in doxorubicin-resistant breast cancer cells.

Background: Doxorubicin resistance remains a major therapeutic challenge leading to poor survival prognosis and treatment failure in breast cancer. Although doxorubicin induces massive changes in the transcriptional landscape are well known, potential diagnostic or therapeutic targets associated with the reorganization of three-dimensional (3D) chromatin architecture have not yet been systematically investigated. Methods: Here we performed in situ high-throughput chromosome conformation capture (Hi-C) on parental and doxorubicin-resistant MCF7 (MCF7-DR) human breast cancer cells, followed by integrative analysis of HiC, ATAC-seq, RNA-seq and TCGA data. Results: It revealed that A/B compartment switching was positively correlated to genome-wide differential gene expression. The genome of MCF7-DR cells was spatially reorganized into smaller topologically associating domains (TADs) and chromatin loops. We also revealed the contribution of increased chromatin accessibility and potential transcription factor families, including CTCF, AP-1 and bHLH, to gained TADs or loops. Intriguingly, we observed two condensed genomic regions (∼20 kb) with decreased chromatin accessibility flanking TAD boundaries, which might play a critical role in the formation or maintenance of TADs. Finally, combining data from TCGA, we identified a number of gained and lost enhancer-promoter interactions and their corresponding differentially expressed genes involved in chromatin organization and breast cancer signaling pathways, including FA2H, FOXA1 and JRKL, which might serve as potential treatment targets for breast cancer. Conclusion: These data uncovered a close connection between 3D genome reorganization, chromatin accessibility as well as gene transcription and provide novel insights into the epigenomic mechanisms involving doxorubicin resistance in breast cancer.

“TPGS surface modified bilosomes as boosting cytotoxic oral delivery systems of curcumin against doxorubicin resistant MCF-7 breast cancer cells”

The goal of this work was to design nude bilosomes (Bil) and D-alpha-tocopheryl polyethylene glycol succinate (TPGS) surface coated bilosomes as an oral delivery platform for improving the antitumor activity and poor oral permeability of Curcumin (CUR). Twelve different formulae were acquired from 31.22 factorial analysis considering different independent variables: bile salt type; Sodium taurocholate (STC) or Sodium cholate (SC) and weight percent; 1% or 5 % W/W, both at 2 levels respectively, while Span 60:Cholesterol ratio at 3 levels (1:1, 5:1, 9:1). Following optimization, the selected optimum formula was picked up based on the favorable minimum particle size (187.2 ± 2.2 nm), maximum zeta potential value (-41.3 ± 2.2 mV) and maximum entrapment efficiency (93.4 ± 5.1%) which was further coated with TPGS. The mean fluorescence intensity (MFI) of CUR permeated from the optimum TPGS-F7 and CUR-Bil (F7) formulae exhibited 6.6 and 3.4 folds increase respectively adopting ex-vivo duodenal permeation assay relative to that of CUR suspension. Moreover, the cellular uptake efficiency via the established Caco-2 cells revealed that the uptake of CUR was 61.9 ± 5.3% and 34.76 ± 0.61% from TPGS-F7 and CUR-Bil (F7) relative to the uptake efficiency of CUR suspension (7.4 ± 2.12%). Coherently, TPGS-CUR-Bil showed excellent response expressed in dominant reduction in IC50 value (2.8 ± 0.07 µg/ml) against multidrug resistant (MDR) tumors following 48 h incubation of Doxorubicin Resistant Breast Cancer (MCF-7/ADR) cell lines.

Artemisinin-isatin hybrids with potential antiproliferative activity against breast cancer

Three series of artemisinin-isatin hybrids 8a-i , 10a-c and 11a-e were designed, synthesized and evaluated for their antiproliferative activity against breast cancer cells (MCF-7, MDA-MB-231 and doxorubicin-resistant MCF-7 (MCF-7/DOX)), as well as the cytotoxicity towards normal MCF-10A breast cells. The preliminary results showed that a significant part of the synthesized hybrids (IC 50 : 20.7–99.9 µM) were active against both drug-sensitive and doxorubicin-resistant breast cancer cell lines. The structure–activity relationship illustrated that the linker between artemisinin and isatin moieties as well as the substituents on C-3 and C-5 position of isatin motif had great influence on the activity. In particular, hybrids 11c,d were found to be most active against all tested breast cancer cell lines, and their activity was not inferior to that of doxorubicin. Therefore, hybrids 11c,d could serve as useful templates for the development of novel anti-breast cancer agents.

Inhibitory Effect of Ursolic Acid on the Migration and Invasion of Doxorubicin-Resistant Breast Cancer.

The cause of death in most breast cancer patients is disease metastasis and the occurrence of multidrug resistance (MDR). Ornithine decarboxylase (ODC), which is involved into multiple pathways, is closely related to carcinogenesis and development. Ursolic acid (UA), a natural triterpenoid compound, has been shown to reverse the MDR characteristics of tumor cells. However, the effect of UA on the invasion and metastasis of tumor cells with MDR is not known. Therefore, we investigated the effects of UA on invasion and metastasis, ODC-related polyamine metabolism, and MAPK-Erk-VEGF/MMP-9 signaling pathways in a doxorubicin-resistant breast cancer cell (MCF-7/ADR) model. The obtained results showed that UA significantly inhibited the adhesion and migration of MCF-7/ADR cells, and had higher affinities with key active cavity residues of ODC compared to the known inhibitor di-fluoro-methyl-ornithine (DFMO). UA could downregulate ODC, phosphorylated Erk (P-Erk), VEGF, and matrix metalloproteinase-9 (MMP-9) activity. Meanwhile, UA significantly reduced the content of metabolites of the polyamine metabolism. Furthermore, UA increased the intracellular accumulation of Dox in MCF-7/ADR cells. Taken together, UA can inhibit against tumor progression during the treatment of breast cancer with Dox, and possibly modulate the Erk-VEGF/MMP-9 signaling pathways and polyamine metabolism by targeting ODC to exert these effects.

The Long Non-Coding RNA SAMMSON Is a Regulator of Chemosensitivity and Metabolic Orientation in MCF-7 Doxorubicin-Resistant Breast Cancer Cells.

Simple SummaryBreast cancer is the most common cancer in women, representing about one third of cancers in developed countries. Despite recent advances in diagnostic methods and increasingly early detection, breast cancer recurrence occurs in more than 20% of patients. Chemoresistance represents an important cause of this recurrence, but the mechanisms involved in this phenomenon, are still largely unknown. One feature of chemoresistant cancer cells is the reorientation of the energetic metabolism to sustain cell proliferation. Recently, long non-coding RNAs (lncRNAs) have emerged as important regulators of cellular metabolic orientation. In the present work, we gave special attention to the long non-coding RNA SAMMSON and addressed the role of this lncRNA in metabolic orientation and chemoresistance of doxorubicin-resistant breast cancer cells. The results shed light on the possible modulation of the SAMMSON expression as an innovative therapeutic approach to target chemoresistant cancer cells specifically.Despite improvements in therapeutic strategies for treating breast cancers, tumor relapse and chemoresistance remain major issues in patient outcomes. Indeed, cancer cells display a metabolic plasticity allowing a quick adaptation to the tumoral microenvironment and to cellular stresses induced by chemotherapy. Recently, long non-coding RNA molecules (lncRNAs) have emerged as important regulators of cellular metabolic orientation. In the present study, we addressed the role of the long non-coding RNA molecule (lncRNA) SAMMSON on the metabolic reprogramming and chemoresistance of MCF-7 breast cancer cells resistant to doxorubicin (MCF-7dox). Our results showed an overexpression of SAMMSON in MCF-7dox compared to doxorubicin-sensitive cells (MCF-7). Silencing of SAMMSON expression by siRNA in MCF-7dox cells resulted in a metabolic rewiring with improvement of oxidative metabolism, decreased mitochondrial ROS production, increased mitochondrial replication, transcription and translation and an attenuation of chemoresistance. These results highlight the role of SAMMSON in the metabolic adaptations leading to the development of chemoresistance in breast cancer cells. Thus, targeting SAMMSON expression levels represents a promising therapeutic route to circumvent doxorubicin resistance in breast cancers.

The Doxorubicin-Induced G2/M Arrest in Breast Cancer Cells Modulated by Natural Compounds Naringenin and Hesperidin

Doxorubicin as the common drug for breast cancer has been widely proposed to use in combine with a natural compound in order to overcome its side effects such as cardiotoxicity and resistance. Previously, we reported that naringenin and hesperidin, the abundant flavanons in citrus fruit peel, increased cytotoxic and apoptosis activities of doxorubicin in doxorubicin resistant breast cancer cells (T47D and MCF-7 cells). Since doxorubicin arrests G2/M phase in most cancer cells, both flavanons are speculated to affect the similar phase in breast cancer cells. Cell cycle distributions were determined by flowcytometry using propidium iodide (PI) to stain DNA of the cells. Combination of naringenin or hesperidin with doxorubicin increased accumulation of T47D cells in G2/M phase, while in MCF-7 cells, accumulated cells in G2/M phase were decreased, accompanying with slightly increased in G1 phase. Naringenin itself had no effect on cell cycle of both cells. Whereas, hesperidin arrested G2/M and G1 phases in T47D and MCF-7 cells, respectively. The different effect of naringenin and hesperidin in T47D and MCF-7 cells is most likely caused by difference of p53 status. In p53 mutant, T47D cells, naringenin and hesperidin supported mechanism of doxorubicin to arrest at G2/M that to be considered via p53-independent pathway. Whereas, in p53 wild-type MCF-7 cells, naringenin and hesperidin decreased G2/M arrest, suggesting that both flavanons do not utilize cell cycle arrest for their anticancer activity with doxorucibin. This study revealed that potential co-chemoterapeutic agents, naringenin and hesperidin distinctly modulated cell cycle arrest induced by doxorubicin according to the characteristic of breast cancer cells.Keywords: naringenin, hesperidin, doxorubicin, cell cycle, breast cancer cells.

Anticancer effects of asiatic acid against doxorubicin-resistant breast cancer cells via an AMPK-dependent pathway in vitro

Background and purposeAsiatic acid is one of the active compounds isolated from Centella asiatica and has been used to treat many diseases, including hypertension, pulmonary fibrosis, and cancer. It exhibits anticancer effects in many cancers, such as ovarian, lung and colon cancer; however, its anticancer effects in breast cancer and the underlying mechanism are not fully understood. Chemoresistance is often induced after the use of chemotherapy, and it is a challenging problem in cancer therapy. The effects of asiatic acid on chemoresistance in breast cancer have never been studied. Therefore, the aim of the present study was to examine the anticancer effects of asiatic acid in doxorubicin-resistant breast cancer MCF-7 cells. MethodsThe cells were incubated with asiatic acid at 0-160 μM for 2-24 h. Cell viability and cytotoxicity were evaluated by 3-[4, 5-dimethyl-2-thiazolyl]-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Florescent images were taken using a confocal microscope. P-gp function and apoptosis assays were performed using flow cytometry. Caspase activity was measured with the Caspase-Glo™ Assay System. The phosphorylation and expression of relevant proteins were assessed by western blots. Molecular docking was performed and scored by AutoDock. Cellular thermal shift assay (CETSA) was applied for experimental valuation. ResultsOur data demonstrated that asiatic acid induced cell death in multiple ways, including reactive oxygen species production, adenosine triphosphate (ATP) content reduction, and adaptive immunity balance via intrinsic apoptosis, AMP-activated protein kinase (AMPK), programmed death-ligand 1 (PD-L1), and indirect nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional pathways, using experimental validation and in silico analysis. Moreover, asiatic acid also enhanced the sensitivity of doxorubicin-resistant MCF-7 cells to doxorubicin by improving P-glycoprotein (P-gp) function. ConclusionsThis study provides evidence that asiatic acid has strong anticancer effects to reverse multidrug resistance and could be developed as a promising adjuvant drug for the treatment of chemoresistant cancer.

Integrated Chromatin Accessibility and Transcriptome Landscapes of Doxorubicin-Resistant Breast Cancer Cells.

BackgroundDoxorubicin is one of the most effective chemotherapeutic drugs for breast cancer while its common drug resistance leads to poor patient prognosis and survival. Growing evidence indicate dynamically reorganized chromatin allows rapid access of the gene regulatory machinery to open genomic regions facilitating subsequent gene expression through direct transcription factor (TF) activation and regulatory element binding.MethodsTo better understand the regulatory network underlying doxorubicin resistance in breast cancer cells, we explored the systematic alterations of chromatin accessibility and gene expression by the assay for transposase-accessible chromatin using sequencing (ATAC-seq) in combination with RNA sequencing, followed by integrative analysis to identify potential regulators and their targets associated with differentially accessible regions (DARs) in doxorubicin-resistant MCF7 (MCF7-DR) cells.ResultsA total of 3,963 differentially expressed genes (DEGs) related to doxorubicin resistance were identified, including dramatically up-regulated MT1E, GSTP1, LDHB, significantly down-regulated TFF1, UBB, DSCAM-AS1, and histone-modifying enzyme coding genes HDAC2, EZH2, PRMT5, etc. By integrating with transcriptomic datasets, we identified 18,228 DARs in MCF7-DR cells compared to control, which were positively correlated with their nearest DEGs (r = 0.6). There were 11,686 increased chromatin-accessible regions, which were enriched in up-regulated genes related to diverse KEGG pathways, such as the cell cycle, regulation of actin cytoskeleton, signaling pathways of MAPK, PI3K/Akt and Hippo, which play essential roles in regulating cell apoptosis, proliferation, metabolism, and inflammatory responses. The 6,542 decreased chromatin-accessible regions were identified for the declined doxorubicin-associated biological processes, for instance, endocrine and insulin resistance, central carbon metabolism, signaling pathways of TGF-beta and P53. Combining data from TCGA, analyses of the DAR sequences associated with the DNA-binding motifs of significantly enriched TF families including AP-1, TEAD and FOX, indicated that the loss-function of FOXA1 might play a critical role in doxorubicin-resistant breast cancer cells (DOX-R BCCs).ConclusionThese data exhibit the non-genetic landscape of chromatin accessibility and transcript levels in the DOX-R BCCs, and provide clear insights and resources for the detection of critical TFs and potential cis-regulatory elements-based putative therapeutic targets.

Nitric Oxide Photo-Donor Hybrids of Ciprofloxacin and Norfloxacin: A Shift in Activity from Antimicrobial to Anticancer Agents.

The potential anticancer effect of fluoroquinolone antibiotics has been recently unveiled and related to their ability to interfere with DNA topoisomerase II. We herein envisioned the design and synthesis of novel Ciprofloxacin and Norfloxacin nitric oxide (NO) photo-donor hybrids to explore the potential synergistic antitumor effect exerted by the fluoroquinolone scaffold and NO eventually produced upon light irradiation. Anticancer activity, evaluated on a panel of tumor cell lines, showed encouraging results with IC50 values in the low micromolar range. Some compounds displayed intense antiproliferative activity on triple-negative and doxorubicin-resistant breast cancer cell lines, paving the way for their potential use to treat aggressive, refractory and multidrug-resistant breast cancer. No significant additive effect was observed on PC3 and DU145 cells following NO release. Conversely, antimicrobial photodynamic experiments on both Gram-negative and Gram-positive microorganisms displayed a significant killing rate in Staphylococcus aureus, accounting for their potential effectiveness as selective antimicrobial photosensitizers.

STAT5a Confers Doxorubicin Resistance to Breast Cancer by Regulating ABCB1.

Chemoresistance is a daunting challenge to the prognosis of patients with breast cancer. Signal transducer and activator of transcription (STAT) 5a plays vital roles in the development of various cancers, but its function in breast cancer is controversial, and its role in chemoresistance in breast cancer remains unexplored. Here we identified STAT5a as a chemoresistance inducer that regulates the expression of ABCB1 in breast cancer and can be targeted by pimozide, an FDA-approved psychotropic drug. First, we found that STAT5a and ABCB1 were expressed at higher levels in doxorubicin-resistant cell lines and chemoresistant patients, and their expression was positively correlated. Then, we confirmed the essential roles of STAT5a and ABCB1 in doxorubicin resistance in breast cancer cells and the regulation of ABCB1 transcription by STAT5a. Subsequently, the efficacy of pimozide in inhibiting STAT5a and sensitizing doxorubicin-resistant breast cancer cells was tested. Finally, we verified the role of STAT5a in doxorubicin resistance in breast cancer and the efficacy of pimozide in reversing this resistance in vivo. Our study demonstrated the vital role of STAT5a in doxorubicin resistance in breast cancer. Targeting STAT5a might be a promising strategy for treating doxorubicin-resistant breast cancer. Moreover, repurposing pimozide for doxorubicin resensitization is attractive due to the safety profile of pimozide.