DOX-resistant MCF-7 Research Articles

The targeted photodynamic therapy of breast cancer with novel AS1411-indium(III) phthalocyanine conjugates

In the study, the novel indium(III) phthalocyanines containing 4-mercaptopyridine groups as substituents on the peripheral (Pc3) or non-peripheral (Pc8) tetra-and peripheral octa (Pc13) positions were synthesized. After then, the synthesized phthalocyanines were converted to their water-soluble derivatives that are Pc5, Pc10, and Pc15 by the quaternization of the nitrogen atoms on the substituents. These new phthalocyanines have been characterized by various spectroscopic methods such as FT-IR, 1HNMR, elemental analysis, UV–vis, MALDI-TOF mass spectra. Photochemical properties were also investigated for the synthesized phthalocyanines. In this study; quaternized derivatives were studied in DMSO and aqueous solutions, while non-quaternized derivatives were studied only in DMSO. The interaction between AS1411 and three phthalocyanines (Pc5, Pc10, and Pc15) was investigated using spectroscopic methods and electrochemical impedance spectroscopy technique combined with pencil graphite electrodes (PGEs). The cytotoxic activity of AS1411 and each phthalocyanine was investigated in the MCF-7 and doxorubicin (Dox) resistant MCF-7/DOX-R cell lines in the presence and absence of Dox. The photodynamic therapy (PDT) activity of Pc5, Pc10, and Pc15 and their AS1411 conjugates was investigated on MCF-7, MCF-7/DOX-R and MCF-10A cells. The IC50 values for MCF-7 cells were found as 1.1, 0.46, and 0.46 mM for Pc5 and 0.58, 0.34, and 0.32 mM for Pc5-AS1411 conjugate in the absence of irradiation and radiation with 7 J and 20 J. The values for MCF-7/DOX-R cells were found 0.81, 0.30, and 0.11 mM for Pc5 and 0.39, 0.12, and 0.15 mM for Pc5-AS1411 conjugate without irradiation and radiation with 7 J and 20 J, respectively. Apoptosis and cell imaging studies showed that conjugation of the phthalocyanines with AS1411 induced apoptosis in both cell lines and increases the intracellular entry of phthalocyanine Pc5.

Synergistic combination of doxorubicin with hydralazine, and disulfiram against MCF-7 breast cancer cell line.

Disulfiram and hydralazine have recently been reported to have anti-cancer action, and repositioned to be used as adjuvant in cancer therapy. Chemotherapy combined with other medications, such as those that affect the immune system or epigenetic cell profile, can overcome resistance with fewer adverse effects compared to chemotherapy alone. In the present study, a combination of doxorubicin (DOX) with hydrazine (Hyd) and disulfiram (Dis), as a triple treatment, was evaluated against wild-type and DOX-resistant MCF-7 breast cancer cell line. Both wild-type MCF-7 cell line (MCF-7_WT) and DOX-resistant MCF-7 cell line (MCF-7_DoxR) were treated with different combination ratios of DOX, Dis, and Hyd followed by measuring the cell viability using the MTT assay. Synergism was determined using a combination index, isobologram analysis, and dose-reducing index. The anti-proliferation activity and mechanism of the triple combination were investigated by apoptosis analysis. The results showed a reduction in the IC50 values of DOX in MCF-7_WT cells (from 0.24 μM to 0.012 μM) and MCF-7_DoxR cells (from 1.13 μM to 0.44 μM) when treated with Dis (0.03μM), and Hyd (20μM) combination. Moreover, The triple combination DOX/Hyd/Dis induced significant apoptosis in both MCF-7_WT and MCF-7_DoxR cells compared to DOX alone. The triple combination of DOX, Dis, and Hyd showed a synergistic drugs combination to decrease the DOX dose needed to kill both MCF-7_WT and MCF-7_DoxR cancer cells and enhanced chemosensitivity to DOX.

Doxorubicin resistance in breast cancer is mediated via the activation of FABP5/PPARγ and CaMKII signaling pathway.

Breast cancer is the most prevalent malignancy among women. Doxorubicin (Dox) resistance was one of the major obstacles to improving the clinical outcome of breast cancer patients. The purpose of this study was to investigate the relationship between the FABP signaling pathway and Dox resistance in breast cancer. The resistance property of MCF-7/ADR cells was evaluated employing CCK-8, Western blot (WB), and confocal microscopy techniques. The glycolipid metabolic properties of MCF-7 and MCF-7/ADR cells were identified using transmission electron microscopy, PAS, and Oil Red O staining. FABP5 and CaMKII expression levels were assessed through GEO and WB approaches. The intracellular calcium level was determined by flow cytometry. Clinical breast cancer patient's tumor tissues were evaluated by immunohistochemistry to determine FABP5 and p-CaMKII protein expression. In the presence or absence of FABP5 siRNA or the FABP5-specific inhibitor SBFI-26, Dox resistance was investigated utilizing CCK-8, WB, and colony formation methods, and intracellular calcium level was examined. The binding ability of Dox was explored by molecular docking analysis. The results indicated that the MCF-7/ADR cells we employed were Dox-resistant MCF-7 cells. FABP5 expression was considerably elevated in MCF-7/ADR cells compared to parent MCF-7 cells. FABP5 and p-CaMKII expression were increased in resistant patients than in sensitive individuals. Inhibition of the protein expression of FABP5 by siRNA or inhibitor increased Dox sensitivity in MCF-7/ADR cells and lowered intracellular calcium, PPARγ, and autophagy. Molecular docking results showed that FABP5 binds more powerfully to Dox than the known drug resistance-associated protein P-GP. In summary, the PPARγ and CaMKII axis mediated by FABP5 plays a crucial role in breast cancer chemoresistance. FABP5 is a potentially targetable protein and therapeutic biomarker for the treatment of Dox resistance in 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.

Does insulin make breast cancer cells resistant to doxorubicin toxicity?

The effects of insulin on the doxorubicin (Dox) sensitivity of breast cancer cell line MCF-7 and its Dox-resistant counterpart MCF-7/Dox were studied and glucose metabolism, content of essential minerals, and the expression of several microRNAs in these cells upon exposure to insulin and Dox were compared. Cell viability colorimetric assay, colorimetric enzymatic technique, flow cytometry, immunocytochemical techniques, inductively-coupled plasma atomic emission spectroscopy, and quantitative polymerase chain reaction were used in the study. We found that insulin in high concentration significantly suppressed Dox toxicity, especially in parental MCF-7 cell line. The increase in proliferative activity triggered by insulin in MCF-7 but not MCF-7/Dox cells occurred in the setting of the increased level of specific binding sites for insulin and increased glucose uptake. Insulin treatment of MCF-7 cells in low and high concentrations resulted in the increase of Mg, Ca, and Zn content while in DOX-resistant cells, only Mg content increased upon exposure to insulin. High concentration of insulin increased the expression of kinase Akt1, P-glycoprotein 1 (P-gp1) and DNA excision repair protein ERCC-1 in MCF-7 cells, while in MCF-7/Dox cells, Akt1 expression decreased, and cytoplasmic expression of P-gp1 increased. In addition, insulin treatment affected expression of miR-122-5p, miR-133a-3p, miR-200b-3p, and miR-320a-3p. The decreased manifestation of biological effects of insulin in Dox-resistant cells could be partly explained by the different patterns of energy metabolism in MCF-7 cells and their Dox-resistant counterpart.

Mitochondria-Targeting Polyprodrugs to Overcome the Drug Resistance of Cancer Cells by Self-Amplified Oxidation-Triggered Drug Release.

The multi-drug resistance (MDR) of cancers is one of the main barriers for the success of diverse chemotherapeutic methods and is responsible for most cancer deaths. Developing efficient approaches to overcome MDR is still highly desirable for efficient chemotherapy of cancers. The delivery of targeted anticancer drugs that can interact with mitochondrial DNA is recognized as an effective strategy to reverse the MDR of cancers due to the relatively weak DNA-repairing capability in the mitochondria. Herein, we report on a polyprodrug that can sequentially target cancer cells and mitochondria using folic acid (FA) and tetraphenylphosphonium (TPP) targeting moieties, respectively. They were conjugated to the terminal groups of the amphiphilic block copolymer prodrugs composed of poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) and copolymerized monomers containing cinnamaldehyde (CNM) and doxorubicin (DOX). After self-assembly into micelles with the suitable size (∼30 nm), which were termed as TF@CNM + DOX, and upon intravenous administration, the micelles can accumulate in tumor tissues. After FA-mediated endocytosis, the endosomal acidity (∼pH 5) can trigger the release of CNM from TF@CNM + DOX micelles, followed by enhanced accumulation into the mitochondria via the TPP target. This promotes the overproduction of reactive oxygen species (ROS), which can subsequently enhance the intracellular oxidative stress and trigger ROS-responsive release of DOX into the mitochondria. TF@CNM + DOX shows great potential to inhibit the growth of DOX-resistant MCF-7 ADR tumors without observable side effects. Therefore, the tumor and mitochondria dual-targeting polyprodrug design represents an ideal strategy to treat MDR tumors through improvement of the intracellular oxidative level and ROS-responsive drug release.

Discovery of a novel highly potent and low-toxic jatrophane derivative enhancing the P-glycoprotein-mediated doxorubicin sensitivity of MCF-7/ADR cells

Use of novel modulators targeting P-glycoprotein (P-gp, ABCB1 transporter) is among the most accepted strategies for overcoming multidrug resistance in cancer chemotherapy. In the current study, we pursued our structure-activity relationship studies of jatrophane derivatives by structural modification of compound 1, a natural jatrophane isolated from Euphorbia. sororia A. Nine compounds exhibited higher reversal activity in P-gp/ABCB1-mediated MCF-7/ADR cells than verapamil (VRP). The cytotoxicity and doxorubicin (DOX) intracellular accumulation effects of jatrophane derivatives were assessed in normal HEK293T cells and DOX-resistant MCF-7/ADR cells. The most potent compound 17 merits multiple activities, including (1) high efficiency (EC50 = 182.17 ± 32.67 nM) in reversing P-gp-mediated resistance to DOX, low cytotoxicity, and a high therapeutic index; and (2) increasing the accumulation of Rhodamine123 (Rho123) and DOX in a dose-dependent manner compared to verapamil in MCF-7/ADR cells. Our results indicated that the reversal activity of 17 was due to the stimulation of the P-gp ATPase activity instead of the direct inhibition of P-gp protein expression. A docking study demonstrated that 17 has a high binding affinity toward the DOX recognition site of P-gp. This resulted in 17 enhancing the sensitivity of DOX to MCF-7/ADR cells by stimulating P-gp ATPase activity, increasing intracellular DOX and Rho123 concentrations, inhibiting the phosphoinositide 3-kinase/serine-threonine kinase mediated by DOX and further reducing the expression of P-gp. This study provides a promising P-gp inhibitor for reversing multidrug resistance and provides a basis for further research.

Apigenin alleviates resistance to doxorubicin in breast cancer cells by acting on the JAK/STAT signaling pathway.

Breast cancer is the most frequent cancer among women. Despite the effectiveness of Doxorubicin (DOX) as a chemotherapeutic for the treatment of breast cancer, the therapy-resistance remains unsolvable. Apigenin is a natural dietary flavonoid with potential anticancer activities. Our study's intention was to evaluate the effect of Apigenin on DOX resistance in MCF-7 cells. DOX-resistant MCF-7 cell line (MCF-7R) was developed by treating MCF-7 cells with increasing concentrations of DOX (0-100 µM). The viability of cell lines was assayed using MTT method. Quantitative polymerase chain reaction method was performed to measure multidrug-resistance 1 (MDR1) gene expression level. The expression of MDR1, Janus kinase 2 (JAK2) and Signal transducer and activator of transcription 3 (STAT3) proteins were determined by western blotting. MCF-7R cell line showed resistance to DOX in comparison to MCF-7 cells. Apigenin had a significant effect on the reduction of viability of both MCF-7 and MCF-7R cell lines. However, DOX-resistance in the MCF-7 cell line was considerably decreased due to the co-treatment of MCF-7R cells with Apigenin. This natural compound also downregulated the expression of MDR1 at mRNA and protein levels both in resistant and non-resistant cells. Apigenin significantly prohibited the phosphorylation and activation of JAK2 and STAT3 proteins both in MCF-7 and MCF-7R cell lines. The present results suggested, for the first time, Apigenin as an ideal therapeutic for ameliorating DOX resistance in breast cancer. These data also proposed a novel mechanism for the anti-resistance activity of Apigenin by regulating the JAK2/STAT3/MDR1 axis.

Reversing multi-drug resistance by polymeric metformin to enhance antitumor efficacy of chemotherapy

Multi-drug resistance (MDR) in breast cancer poses a great threat to chemotherapy. The expression and function of the ATP binding cassette (ABC) transporter are the major cause of MDR. Herein, a linear polyethylene glycol (PEI) conjugated with dicyandiamide, which called polymeric metformin (PolyMet), was successfully synthesized as a simple and biocompatible polymer of metformin. PolyMet showed the potential to reverse MDR by inhibiting the efflux of the substrate of ATP-binding cassette (ABC) transporter from DOX resistant MCF-7 cells (MCF-7/DOX). To test its MDR reversing effect, PolyMet was combined with DOX to treat mice carrying MCF-7/DOX xenografts. In order to decrease the toxicities of DOX and delivery PolyMet and DOX to tumor at the same time, PolyMet was complexed with poly-γ-glutamic acid-doxorubicin (PGA-DOX) electrostatically at the optimal ratio of 2:3, which were further coated with lipid membrane to form lipid/PolyMet-(PGA-DOX) nanoparticles (LPPD). The particle size of LPPD was 165.8 nm, and the zeta potential was +36.5 mV. LPPD exhibited favorable cytotoxicity and cellular uptake in MCF-7/DOX. Meanwhile, the bioluminescence imaging and immunohistochemical analysis indicated that LPPD effectively conquered DOX-associated MDR by blocking ABC transporters (ABCB1 and ABCC1) via PolyMet. Remarkably, LPPD significantly inhibited the tumor growth and lowered the systemic toxicity in a murine MCF-7/DOX tumor model. This is the first time to reveal that PolyMet can enhance the anti-tumor efficacy of DOX by dampening ABC transporters and activating the AMPK/mTOR pathway, which is a promising strategy for drug-resistant breast cancer therapy.

A pore-forming protein-induced surface-enhanced Raman spectroscopic strategy for dynamic tracing of cell membrane repair

SummaryThe plasma membrane repair holds significance for maintaining cell survival and homeostasis. To achieve the sensitive visualization of membrane repair process for revealing its mechanism, this work designs a perforation-induced surface-enhanced Raman spectroscopy (SERS) strategy by conjugating Raman reporter (4-mercaptobenzoic acid) loaded gold nanostars with pore-forming protein streptolysin O (SLO) to induce the SERS signal on living cells. The SERS signal obviously decreases with the initiation of membrane repair and the degradation of SLO pores due to the departure of gold-nanostar-conjugated SLO. Thus, the designed strategy can dynamically visualize the complete cell membrane repair and provide a sensitive method to demonstrate the SLO endocytosis- and exocytosis-mediated repairing mechanism. Using DOX-resistant MCF-7 cells as a model, a timely repair-blocking technology for promoting the highly efficient treatment of drug-resistant cancer cells is also proposed. This work opens an avenue for probing the plasma membrane repairing mechanisms and designing the precision therapeutic schedule.

Synergistic Therapy of Doxorubicin with Cationic Anticancer Peptide L-K6 Reverses Multidrug Resistance in MCF-7/ADR Cancer Cells In Vitro via P-glycoprotein Inhibition

Multidrug resistance (MDR) is one of the major obstacles to efficient chemotherapy against cancers, resulting from the overexpression of drug efflux transporters such as P-glycoprotein (P-gP). In the present study, we aimed to evaluate the MDR reversal activity and synergistic therapeutic potential of cationic anticancer peptide L-K6 with doxorubicin (DOX) on P-gP-overexpressing and DOX-resistant MCF-7/ADR human breast cancer cells. Flow cytometry and confocal laser scanning microscopy were used to determine the intracellular accumulation of DOX and another P-gP substrate, Rho123. P-gP-Glo assay, Western blot and Biacore analysis were further performed to evaluate the P-gP function and expression. The cytotoxicity in MCF-7 or MCF-7/ADR cells was measured by MTT assay. Flow cytometry assay and confocal laser scanning microscopy observation clearly revealed an increased intracellular accumulation of DOX and Rho123 in MCF-7/ADR cells treated with L-K6, suggesting a P-gP inhibiting potential. Biacore analysis, P-gP-Glo assay and Western blot further confirmed that L-K6 could directly interact with P-gP, inhibit P-gP function and decrease P-gP expression in MCF-7/ADR cells. In addition, as expected, the data from MTT assay indicated that L-K6 restored the sensitivity of MCF-7/ADR cells to DOX, indicating a MDR reversal potential and a promising synergistic anticancer activity. All these findings may provide experimental evidence to support the promising applications and synergistic therapeutic potential of peptidic P-gP inhibitors against MDR cancer.

Reversing Chemotherapy Resistance by a Synergy between Lysosomal pH-Activated Mitochondrial Drug Delivery and Erlotinib-Mediated Drug Efflux Inhibition.

Mitochondrial drug delivery has attracted increasing attention in various mitochondrial dysfunction-associated disorders such as cancer owing to the important role of energy production. Herein, we report a lysosomal pH-activated mitochondrial-targeting polymer nanoparticle to overcome drug resistance by a synergy between mitochondrial delivery of doxorubicin (DOX, an anticancer drug) and erlotinib-mediated inhibition of drug efflux. The obtained nanoparticles, DE-NPs could maintain negative charge and have long blood circulation while undergoing charge reversal at lysosomal pH after internalization by cancer cells. Thereafter, the acidity-activated polycationic and hydrophobic polypeptide domains boost lysosomal escape and mitochondrial-targeting drug delivery, leading to mitochondrial dysfunction, ATP suppression, and cell apoptosis. Moreover, the suppressed ATP supply and erlotinib enabled dual inhibition of drug efflux by DOX-resistant MCF-7/ADR cells, leading to significantly augmented intracellular DOX accumulation and a synergistic anticancer effect with a 17-fold decrease of IC50 relative to DOX. In vivo antitumor study demonstrates that DE-NPs efficiently suppressed the tumor burden in MCF-7/ADR tumor-bearing mice and led to negligible toxicity. This work establishes that a combination of mitochondrial drug delivery and drug efflux inhibition could be a promising strategy for combating multidrug resistance.

Nuclear factor-κB signaling inhibitors revert multidrug-resistance in breast cancer cells

The emergence of multidrug resistance (MDR) is among the crucial obstacles to breast cancer therapy success. The transcription factor nuclear factor (NF)-κB is correlated to the pathogenesis of breast cancer and resistance to therapy. NF-κB augments the expression of MDR1 gene, which encodes for the membrane transporter P-glycoprotein (P-gp) in cancer cells. Since NF-κB activity is considered to be relatively high in particular when it comes to breast cancer, in the present work, we proposed that the inhibition of NF-κB activity can augment and enhance the sensitivity of breast cancer cells to chemotherapy such as doxorubicin (DOX) by virtue of MDR modulation. Our results demonstrated that the DOX-resistant MCF-7 and MDA-MB-231 clones exhibit higher NF-κB (p65) activity, which is linked to the upregulated expression of ABCB1 and ABCC1 transporter proteins. Combined treatment with NF-kB inhibitors (pentoxifylline and bortezomib) sensitized the resistant breast cancer cells to DOX. Such synergy was compromised by forced overexpression of p65. The DOX/NF-κB inhibitor combinations hampered NF-κB (p65) activation and downregulated MDR efflux transporters' level. Breast cancer cell migration was sharply suppressed in cells co-treated with DOX/NF-κB inhibitors. The same treatments successfully enhanced DOX-mediated induction of apoptosis, which is reflected by the elevated ratio of annexin-V/PI positively stained cells, along with the activation of other apoptotic markers. In conclusion, the data generated from this study provide insights for future translational investigations introducing the use of the clinically approved NF-κB inhibitors as an adjuvant in the treatment protocols of resistant breast cancer to overcome the multidrug resistance and enhance the therapeutic outcomes.

Tanshinone II A improves the chemosensitivity of breast cancer cells to doxorubicin by inhibiting β-catenin nuclear translocation.

Numerous evidence linkaberrant nuclear β-catenin accumulation to the development of breast cancer resistance, therefore, targeted inhibition of β-catenin nuclear translocation may effectively improve the chemosensitivity of breast cancer. Doxorubicin (Dox) is the most commonly used chemotherapeutic drug for breast cancer. Here, we determined that tanshinone II A (Tan II A) could improve the sensitivity of Dox-resistant breast cancer MCF-7/dox cells to Dox, and evaluated whether the sensitization effect of Tan II A on Dox was targeted to inhibit β-catenin nuclear translocation. The results showed that Tan II A not only significantly inhibited the nuclear translocation of β-catenin in MCF-7/dox cells treated by Dox but also inhibited the nuclear translocation of β-catenin in MCF-7 cells treated by Dox to a certain degree. Furthermore, when the above two cells treated by Dox combined with Tan II A were intervened with β-catenin agonist WAY-262611, with the re-nuclear translocation of β-catenin in the cells, the sensitization effect of Tan II A on Dox was greatly reduced. These results indicated that Tan II A could improve the chemosensitivity of breast cancer cells to Dox by inhibiting β-catenin nuclear translocation. Therefore, Tan II A could be used as a potential chemosensitizer in combination with Dox for breast cancer chemotherapy.

Polyplexes by Polymerized Dequalinium and Bifunctional Aptamer for Mitochondrial Targeting Drug Release to Overcome Drug Resistance.

Drug resistance is one of the major obstacles to the success of cancer chemotherapy. Mitochondrial targeting drugs are increasingly thought to be able to eradicate resistant cancer cells. However, immature drug release outside mitochondria and the absence of multifunctional targeting carriers against tumor mitochondria greatly limit the corresponding therapeutic benefits. Here, we synthesized polymerized dequalinium by integrating dequalinium, lysine, and poly(ethylene glycol) for mitochondrial targeting. The polymerized dequalinium exhibited lower cytotoxicity and stronger gene condensing ability than free dequalinium. We designed AS1411-ATP fusion aptamer to load doxorubicin (DOX) for both tumor targeting and ATP-responsive DOX release. The polyplexes by polymerized dequalinium and bifunctional aptamer can target tumor cells via AS1411 and show improved stability, mitochondrial targeting, DOX release in response to mitochondrial ATP, and enhanced apoptosis-inducing effect on DOX-resistant MCF-7/DOX cells. The present study highlights a promising application of the polyplexes in reversing drug resistance in tumor cells via tumor mitochondrial targeting drug release.

Upconversion Nanoparticle-Based Organosilica-Micellar Hybrid Nanoplatforms for Redox-Responsive Chemotherapy and NIR-Mediated Photodynamic Therapy.

Upconversion nanoparticles (UCNPs) can convert near-infrared light (NIR, 980 or 808 nm) to ultraviolet (UV) or visible light, which can be widely used to improve tissue penetration depth in photodynamic therapy (PDT). Herein, we develop a kind of UCNP-based organosilica-micellar hybrid nanoplatform for redox-responsive chemotherapy and NIR-mediated PDT. The nanoplatform was constructed by the self-assembly of block copolymers polystyrene-b-poly (acrylic acid) and oil-soluble UCNPs in the oil/water system and the subsequent organosilica coating with 3-mercaptopropyltrimethoxysilane molecules. To endow the nanosystem with more stability in biological media, polyethylene glycol molecules were further modified via the Michael addition reaction. As a promising nanocarrier, chlorin e6 (Ce6) and doxorubicin (DOX) molecules were loaded into the hydrophobic core and the disulfide-doped organosilica shell, respectively. With endocytosis by SMMC-7721 tumor cells, the Ce6 and DOX coloaded nanosystem was activated by UCNPs through luminescence resonance energy transfer under the irradiation of 808 nm laser, thus generating cytotoxic 1O2 for NIR-mediated PDT. Meanwhile, DOX was selectively released because of the redox-responsive biodegradation of the disulfide-doped organosilica shell in the glutathione over-expressed SMMC-7721 tumor cells. Based on these, the chemotherapy/PDT combination toxic feature of the multifunctional nanosystem was further demonstrated in the DOX-resistant MCF-7 tumor cells. On the other hand, the Ce6 and DOX coloaded nanosystem exhibited negligible toxicity to the normal 3T3 cell because of the protective effects of organosilica coating. We envision that the resultant hybrid nanoplatform provides us a promising nanocarrier for the combination therapy of redox-responsive safe chemotherapy and efficient NIR-mediated PDT.

Gold Nanorods Functionalized with Cathepsin B Targeting Peptide and Doxorubicin for Combinatorial Therapy against Multidrug Resistance.

Multidrug resistance (MDR) and adverse effects of chemotherapeutic agents are severe issues in clinical cancer treatment. Due to the dysregulation of enzymes in the cancer cells, enzyme-responsive drug delivery systems (DDSs) have been considered as a viable technology for cancer chemotherapy. In the present work, doxorubicin (DOX) is visible after leaving from AuNR-LAX. After treatment with AuNR-LAX, the drug resistance index of DOX-resistant MCF-7/ADR cells was reduced from extremely high 955.0 to 1.7, implying high potential of AuNR-LAX in the MDR phenotype cancer treatment. In addition, the cellular viability of both MCF-7 and MCF-7/ADR cells decreased from 50% to 80% after treatment with AuNR-LAX along (equivalent DOX concentration = 2.3 μg/mL, Au concentration = 30 μg/mL) to below 10% after AuNR-LAX treatment plus radiation of 808 nm, due to the NIR photothermal effect of AuNRs. Human bronchial epithelial cell line 16HBE was chosen to evaluate the adverse effect of AuNR-LAX on the normal cells. At the low concentration, the cytotoxicity of LAX and AuNR-LAX is comparable for breast cancer cell MCF-7 and normal cell 16HBE. It is noted that, at high concentration (with equivalent DOX concentration = 13.1 μg/mL, Au concentration = 167.7 μg/mL), the cellular viability of 16HBE cells is over 50%, whereas that of MCF-7 cancer cells is close to 0, implying the potential of AuNR-LAX in reducing the adverse effects of DOX against normal cells/tissues. Overall, AuNR-LAX showed high potential in overcoming MDR and alleviating adverse effect on normal cells.

Nitric Oxide Stimulated Programmable Drug Release of Nanosystem for Multidrug Resistance Cancer Therapy.

Nitric oxide (NO) molecular messenger can reverse the multidrug resistance (MDR) effect of cancer cells through reducing P-glycoprotein (P-gp) expression, beneficial for creating a favorable microenvironment for the treatment of doxorubicin (Dox)-resistant cancer cells. Development of sophisticated nanosystems to programmably release NO and Dox becomes an efficient strategy to overcome the MDR obstacles and achieve promising therapeutic effects in Dox-resistant cancer. Herein, a NO stimulated nanosystem was designed to engineer a significant time gap between NO and Dox release, promoting MDR cancer therapy. A o-phenylenediamine-containing lipid that can hydrolyze in response to NO was embedded in the phospholipid bilayer structure of liposome to form NO-responsive liposome, which could further encapsulate l-arginine (l-Arg)/Dox-loaded gold@copper sulfide yolk-shell nanoparticls (ADAu@CuS YSNPs) to form ADLAu@CuS YSNPs. Under 808 nm laser irradiation, the unique resonant energy transfer (RET) process and reactive oxygen species (ROS) generation in the confined space of ADLAu@CuS YSNPs could effectively convert l-Arg into NO, regionally destabilizing the phospholipid bilayer structure, as a result of NO release. However, at this early stage Dox could not be released from YSNPs due to the molecular scaffold limit. As the NO release progressed, the NO-responsive liposome layer was deteriorated more severely, allowing Dox to escape. This NO and Dox sequential release of ADLAu@CuS YSNPs could significantly inhibit P-gp expression and enhance Dox accumulation in Dox-resistant MCF-7/ADR cells, leading to promising in vitro and in vivo therapeutic effects and presenting their great potential for MDR cancer therapy.

Abstract 2395: A bispecific T- cell engager antibody (BiTE) against TAG-72/ CD3 for targeted cancer immunotherapy

Abstract Background: Immunotherapies involving cytotoxic T lymphocytes (CTL’s) have been central to cancer immunotherapy. Bi-specific T cell engager antibody (BiTE) therapy has emerged as an effective immunotherapy by redirecting cytotoxic T cells against cell surface protein on tumor cells. Our BiTE antibody targets human tumor associated glycoprotein 72 (TAG-72). TAG-72 is a pan-carcinoma marker expressed on the surfaces of many cancer tissues including breast, prostate, ovary, endometrium, stomach, esophagus, and pancreas. It is not expressed in normal tissues making it an ideal target therapy for cancer. Our BiTE antibody can bind CD3 to activate the T-cell’s while simultaneously binding TAG-72 on the surface of the cancer cell leading to perforin induced cancer cell death. The in vitro and in vivo effects of TAG-72/ CD3 BiTE antibody on different cancer cells are presented here. Methods: We studied in vitro and in vivo effects of TAG-72/ CD3 BiTE antibody on different cancer cells; breast (DOX resistant MCF-7, SKBR3, MDA-MB-175 VII), ovarian (OVCAR-3), endometrium (KLE) and colon (Ls174T). In vitro cytotoxicity assay was performed by flow cytometry and immunofluorescence staining using live/ dead cell labelling fluorescent dyes. The cells were co-cultured with naïve human CD8 T cells with/ without BiTE antibody (1 µg, 5 µg and 10 µg) for different time intervals and assayed. In vivo study was carried out in NSG mice implanted with MCF-7 breast cancer cells + naïve human CD8 T cells and treated with a total of 4 doses of BiTE antibody (200µg/ dose). Results: Different tumor cells showed varying (%) of TAG-72 expression determined by flow cytometry, viz; DOX (55%), SKBR3 (16%), MDA 175 VII (8%), OVCAR-3 (27%), KLE (27%), Ls174T (30%). The BiTE antibody also showed dose dependent binding to these cells. Flow cytometry analysis showed that addition of the BiTE antibody to naïve CD8 T-cells and incubation for 4 days significantly increases tumor cell death as indicated by the Annexin V/ PI+ve signal from DOX (52.4% vs. 41.4% CD8 alone), SKBR-3 (47.9% vs. 30% CD8 alone), MDA 175 VII (23% vs 11% CD8 alone), OVCAR-3 (31.1% vs. 23.8% CD8 alone), KLE (27% vs 13% CD8 alone) and Ls174T (54% vs 29% CD8 alone) respectively (p<0.05). Further, a significant level of IFN-γ secreted by activated T-cells was only detected in the bispecific T-cell engager Ab + CD8 conditions. In vivo data showed good tumor regression at day 45 with tumors measuring (8 mm2) in group treated with BiTE antibody as compared to untreated group (31 mm2) (p<0.01). Conclusion: Our in vitro and in vivo data indicates that the TAG-72/ CD3 BiTE antibody can effectively redirect cytotoxic T cells against different cancer cells expressing TAG-72 glycoprotein and may be effective in the treatment of breast, ovarian, endometrium and colon cancers. Citation Format: Fatema Khambati, Hatem Soliman. A bispecific T- cell engager antibody (BiTE) against TAG-72/ CD3 for targeted cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2395.

Thermal-Responsive Carbon Monoxide (CO) Delivery Expedites Metabolic Exhaustion of Cancer Cells toward Reversal of Chemotherapy Resistance.

Multidrug resistance (MDR) is the main cause of chemotherapy failure, and the mechanism of MDR is largely associated with drug efflux mediated by the adenosine triphosphate (ATP)-binding cassette transporters. Herein, an NIR-light-triggered CO release system based on mesoporous Prussian blue nanoparticles (PB NPs) was developed to reverse MDR via CO-induced metabolic exhaustion. Pentacarbonyl iron (Fe(CO)5) as the CO producer was coupled to PB NPs via coordination interaction, and doxorubicin (Dox) was encapsulated into the pores of PB NPs. After layer-by-layer (LBL) coating, the NPs showed desired serum stability to enhance tumor accumulation. Upon tumor-site-specific NIR light (808 nm) irradiation, the nonlethal temperature elevation cleaved the Fe–CO bond to release CO. CO then expedited mitochondrial metabolic exhaustion to block ATP synthesis and inhibit ATP-dependent drug efflux, thus reversing MDR of the Dox-resistant MCF-7/ADR tumors to potentiate the anticancer efficacy of Dox. In the meantime, CO-mediated mitochondrial exhaustion could upregulate the proapoptotic protein, caspase 3, thus inducing cellular apoptosis and enabling a synergistic anticancer effect with chemotherapy. To the best of our knowledge, this is the first time MDR has been overcome using a CO delivery system. This study provides a promising strategy to realize an effective and safe treatment against MDR tumors and reveals new insights in the use of CO for cancer treatment.