��-Tocopheryl succinate potentiates the paclitaxel-induced apoptosis through enforced caspase 8 activation in human H460 lung cancer cells

Paclitaxel is one of the chemotheraputic drugs widely used for the treatment of nonsmall cell lung cancer (NSCLC) patients. Here, we tested the ability of α-tocopheryl succinate (TOS), another promising anticancer agent, to enhance the paclitaxel response in NSCLC cells. We found that sub-apoptotic doses of TOS greatly enhanced paclitaxel-induced growth suppression and apoptosis in the human H460 NSCLC cell lines. Our data revealed that this was accounted for primarily by an augmented cleavage of poly(ADP-ribose) polymerase (PARP) and enhanced activation of caspase-8. Pretreatment with z-VAD-FMK (a pan-caspase inhibitor) or z-IETD-FMK (a caspase-8 inhibitor) blocked TOS/paclitaxel cotreatment-induced PARP cleavage and apoptosis, suggesting that TOS potentiates the paclitaxel-induced apoptosis through enforced caspase 8 activation in H460 cells. Furthermore, the growth suppression effect of TOS/paclitaxel combination on human H460, A549 and H358 NSCLC cell lines were synergistic. Our observations indicate that combination of paclitaxel and TOS may offer a novel therapeutic strategy for improving paclitaxel drug efficacy in NSCLC patient therapy as well as for potentially lowering the toxic side effects of paclitaxel through reduced drug dosage.     

Let-7i miRNA and platinum loaded nano-graphene oxide platform for detection/reversion of drug resistance and synergetic chemical-photothermal inhibition of cancer cell

The drug resistance of chemotherapy is a major challenge to overcome for antineoplastic agents and the reverse of drug resistant is essential for cancer therapy. Herein, we developed a drug delivery system which can simultaneously detect/reverse the drug resistance and perform synergetic treatment of cancer. In this work, we integrated cyanine5(Cy5) modified mi RNA(let-7 i)(Cy5-mi RNA) and platinum onto nano-graphene oxide(NGO)(30-50 nm) platform to achieve simultaneously detection/reversion of ...     

Cisplatin-induced alteration on membrane composition of A549 cells revealed by ToF-SIMS

Cisplatin has been clinically used for treatment of solid tumors such as non–small-cell lung cancer for decades. However, tumor resistance may be acquired with losing the antitumor activity of cisplatin. As cellular membrane is the first barrier that cisplatin has to overcome before its further action inside the cells, the membrane composition must play a vital role in the cisplatin uptake and excretion, which further influences cisplatin sensitivity. In this work, we applied time-of-flight secondary ion mass spectrometry (ToF-SIMS) surface analysis combined with principle component analysis to distinguish the differences of cell membrane composition between non–small-cell lung cancer cells (A549) and its cisplatin resistant counterpart A549/DDP cells. The decreased phosphatidylcholine content and more abundant cholesterol were observed in the drug resistant cell surfaces, indicating the decreased membrane fluidity of A549/DDP cells. Moreover, we further compared membrane composition of A549 and A549/DDP cells after being treated with different concentrations of cisplatin. A higher composition level of proteins was discovered on all groups of A549/DDP cell membranes. The altered surface chemistry of cellular membranes induced by cisplatin indicates the significance of membrane structures in the drug resistance, which deserves further investigations to this regard.     

METTL3 promotes adriamycin resistance in MCF-7 breast cancer cells by accelerating pri-microRNA-221-3p maturation in a m6A-dependent manner

Breast cancer (BC) is the most prevalent malignant neoplasm among women and is the fifth most common cause of cancer-associated death worldwide. Acquired chemoresistance driven by genetic and epigenetic alterations is a significant clinical challenge in treating BC. However, the mechanism of BC cell resistance to adriamycin (ADR) remains to be elucidated. In this study, we identified the methyltransferase-like 3/microRNA-221-3p/homeodomain-interacting protein kinase 2/Che-1 (METTL3/miR-221-3p/HIPK2/Che-1) axis as a novel signaling event that may be responsible for resistance of BC cells to ADR. A dual-luciferase reporter gene assay was employed to test the presence of miR-221-3p binding sites in the 3′UTR of HIPK2. Drug resistance was evaluated by immunoblotting multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP). Cultured ADR-resistant MCF-7 cells were assayed for their half maximal inhibitory concentration (IC50) values and apoptosis using an MTT assay and Annexin V-FITC/PI-labeled flow cytometry, and the cells were then xenografted into nude mice. METTL3 knockdown was shown to reduce the expression of miR-221-3p by reducing pri-miR-221-3p m6A mRNA methylation, thereby reducing the IC50 value of ADR-resistant MCF-7 cells, reducing the expression of MDR1 and BCRP, and inducing apoptosis. Mechanistically, miR-221-3p was demonstrated to negatively regulate HIPK2 and upregulate its direct target Che-1, thus leading to enhanced drug resistance in ADR-resistant MCF-7 cells. In vitro results were reproduced in nude mice xenografted with ADR-resistant MCF-7 cells. Our work elucidates an epigenetic mechanism of acquired chemoresistance in BC, in support of the METTL3/miR-221-3p/HIPK2/Che-1 axis as a therapeutic target for the improvement of chemotherapy.Subject terms: Breast cancer, Cell biology     

Enhanced induction of Bax gene expression in H460 and H1299 cells with the combined treatment of cisplatin and adenovirus mediated wt-p53 gene transfer

Cytotoxic effect of either cisplatin or p53 gene transfection of lung cancer cells may be different depending on the p53 status of cells. We investigated cytotoxic effects on the combined treatment of cisplatin and adenovirus mediated p53 gene transfer (Avp53) in both H460 and H1299 cells in vitro. The results showed the highest numbers of apoptotic cells in both H460 and H1299 cells following the combined treatment regardless of p53 status in comparison with either cisplatin or Avp53 alone. The expression levels of p53, p21, Bax and ICE were examined to understand a possible cellular signal path of the combined treatment. In western analyses, the patterns of phosphorylated p53 protein were different between Avp53 and combined treatment. The expressions of p21 and Bax were increased in combined treatment, whereas the cleaved form of ICE (20 kD) was not detected. These results suggest that cisplatin induced p53 protein phosphorylation and may activate the downstream of p53 gene expression such as p21 and Bax. The enhanced apoptosis of lung cancer cells by the combined treatment may be useful in the development of clinical therapeutic modality of lung tumors.     

Crucial role of HMGA1 in the self-renewal and drug resistance of ovarian cancer stem cells

Cancer stem cells are a subpopulation of cancer cells characterized by self-renewal ability, tumorigenesis and drug resistance. The aim of this study was to investigate the role of HMGA1, a chromatin remodeling factor abundantly expressed in many different cancers, in the regulation of cancer stem cells in ovarian cancer. Spheroid-forming cancer stem cells were isolated from A2780, SKOV3 and PA1 ovarian cancer cells by three-dimensional spheroid culture. Elevated expression of HMGA1 was observed in spheroid cells along with increased expression of stemness-related genes, such as SOX2, KLF4, ALDH, ABCB1 and ABCG2. Furthermore, spheroid A2780 cells, compared with adherent cells, showed higher resistance to chemotherapeutic agents such as paclitaxel and doxorubicin. HMGA1 knockdown in spheroid cells reduced the proliferative advantage and spheroid-forming efficiency of the cells and the expression of stemness-related genes. HMGA1 overexpression in adherent A2780 cells increased cancer stem cell properties, including proliferation, spheroid-forming efficiency and the expression of stemness-related genes. In addition, HMGA1 regulated ABCG2 promoter activity through HMGA1-binding sites. Knockdown of HMGA1 in spheroid cells reduced resistance to chemotherapeutic agents, whereas the overexpression of HMGA1 in adherent ovarian cancer cells increased resistance to chemotherapeutic agents in vitro. Furthermore, HMGA1-overexpressing A2780 cells showed a significant survival advantage after chemotherapeutic agent treatment in a xenograft tumorigenicity assay. Together, our results provide novel insights regarding the critical role of HMGA1 in the regulation of the cancer stem cell characteristics of ovarian cancer cells, thus suggesting that HMGA1 may be an important target in the development of therapeutics for ovarian cancer patients.     

Valproic Acid Promotes Apoptosis and Cisplatin Sensitivity Through Downregulation of H19 Noncoding RNA in Ovarian A2780 Cells

Cisplatin resistance is one of the main limitations in the treatment of ovarian cancer, which is partly mediated by long noncoding RNAs (lncRNAs). H19 is a lncRNA involving in cisplatin resistance in cancers. Valproic acid (VPA) is a commonly used drug for clinical treatment of seizure disorders. In addition, this drug may display its effects through regulation of noncoding RNAs controlling gene expression. The aim of the present study was the investigation of VPA treatment effect on H19 expression in ovarian cancer cells and also the relation of the H19 levels with apoptosis and cisplatin resistance. Briefly, treatment with VPA not only led to significant increase in apoptosis rate, but also increased the cisplatin sensitivity of A2780/CP cells. We found that following VPA treatment, the expression of H19 and EZH2 decreased, but the expression of p21 and PTEN increased significantly. To investigate the involvement of H19 in VPA-induced apoptosis and cisplatin sensitivity, H19 was inhibited by a specific siRNA. Our results demonstrate that H19 knockdown by siRNA induced apoptosis and sensitized the A2780/CP cells to cisplatin-induced cytotoxicity. These data indicated that VPA negatively regulates the expression of H19 in ovarian cancer cells, which subsequently leads to apoptosis induction, cell proliferation inhibition, and overwhelming to cisplatin resistance. The implication of H19→EZH2→p21/PTEN pathway by VPA treatment suggests that we could repurpose an old drug, valproic acid, as an effective drug for treatment of ovarian cancer in the future.     

Harnessing the Potential Synergistic Interplay Between Photosensitizer Dark Toxicity and Chemotherapy

The combination of photodynamic therapy and taxol- or platinum-based chemotherapy (photochemotherapy) is an effective and promising cancer treatment. While the mechanisms of action of photochemotherapy are actively studied, relatively little is known about the cytotoxicity and molecular alterations induced by the combination of chemotherapy and photosensitizers without light activation in cancer cells. This study investigates the interplay between the photosensitizer benzoporphyrin derivative (BPD) without light activation and cisplatin or paclitaxel in two glioblastoma lines, U87 and U251. The combination effect of BPD and cisplatin in U87 cells is slightly synergistic (combination index, CI = 0.93), showing 1.8- to 2.6-fold lower half-maximal inhibitory concentrations (IC₅₀) compared to those of individual drugs. In contrast, combining BPD and paclitaxel is slightly antagonistic (CI = 1.14) in U87 cells. In U251 cells, the combinations of BPD and cisplatin or paclitaxel are both antagonistic (CI = 1.24 and 1.34, respectively). Western blotting was performed to investigate changes in the expression levels of YAP, TAZ, Bcl-2 and EGFR in U87 and U251 cells treated with BPD, cisplatin and paclitaxel, both as monotherapies and in combination. Our study provides insights into the molecular alterations in two glioma lines caused by each monotherapy and the combinations, in order to inform the design of effective treatments.     

顺铂耐药的分子机制

顺铂被广泛用于多种类型的实体肿瘤的临床治疗.DNA是顺铂的主要靶点,顺铂结合会导致DNA损伤并诱发细胞凋亡.然而,顺铂化疗常常受到内在的和获得性的耐药性的限制.在过去30多年里,大量的研究致力于对顺铂耐药性的理解,并且提出了几种导致顺铂耐药性的分子机制.这些机制显示顺铂的耐药性具有多因素特征.本文系统描述和讨论了顺铂的耐药性机制,包括细胞内药物积累的减少,药物去活作用的增强,DNA修复作用,DNA损伤反应和凋亡通路的变化以及一些间接信号通路的调控影响.     

In situ-prepared homogeneous supramolecular organic framework drug delivery systems(sof-DDSs): Overcoming cancer multidrug resistance and controlled release

Water-soluble three-dimensional porous supramolecular organic frameworks(SOFs)have been demonstrated as a new generation of homogeneous polycationic platforms for anti-cancer drug delivery.The new SOF drug delivery systems(sof-DDSs)can adsorb dianionic pemetrexed(PMX),a clinically used chemotherapeutic agent instantaneously upon dissolving in water,which is driven by both electrostatic attraction and hydrophobicity.The in situ-prepared PMX@SOFs are highly stable and can avoid important release of the drug during plasm circulation and overcome the multidrug resistance of human breast MCF-7/Adr cancer cells to enter the cancer cells.Acidic microenvironment of cancer cells promotes the release of the drug in cancer cells.Both in vitro and in vivo studies have revealed that sof-DDSs considerably improve the treatment efficacy of PMX,leading to 6-12-fold reduction of the IC50 values,as compared with that of PMX alone.The new drug delivery strategy omits the loading process required by most of reported nanoparticle-based delivery systems and thus holds promise for future development of low-cost drug delivery systems     

Paclitaxel‐Loaded Stabilizer‐Free Poly(D,L‐lactide‐co‐glycolide) Nanoparticles Conjugated with Quantum Dots for Reversion of Anti‐Cancer Drug Resistance and Cancer Cellular Imaging

We prepared the PLGA‐loaded anti‐cancer drug and coated it with quantum dots to make it a dual‐function nanoparticles, and analyzed its potential use in cellular imaging and curing cancers. Two cancer cell lines, paclitaxel‐sensitive KB and paclitaxel‐resistant KB paclitaxel‐50 cervical carcinoma cells, were the relativistic models for analysis of the cytotoxicity of free paclitaxel and paclitaxel‐loaded PLGA conjugated with quantum‐dot nanoparticles. The paclitaxel‐loaded PLGA conjugated with quantum dots nanoparticles were significantly more cytotoxic than the free paclitaxel drug in paclitaxel‐resistant KB paclitaxel‐50 cells. This might have been because the cancer cells developed multi‐drug resistance (MDR), which hampered the action of free paclitaxel by pumping its molecules to extracellular areas. Addition of verapamil, a P‐glycoprotein inhibitor, reversed the MDR mechanism and significantly reduced KB paclitaxel‐50 cell viability. As a result, KB paclitaxel‐50 was highly associated with MDR on the cell membrane. The cytotoxicity results indicated that PLGA nanoparticles served as drug carriers and protected the drugs from MDR‐accelerated efflux. Combined quantum dots with PLGA nanoparticles allowed additional functionality for cellular imaging.     

Malformin-A1 (MA1) Sensitizes Chemoresistant Ovarian Cancer Cells to Cisplatin-Induced Apoptosis

High-grade epithelial ovarian cancer is a fatal disease in women frequently associated with drug resistance and poor outcomes. We previously demonstrated that a marine-derived compound MalforminA1 (MA1) was cytotoxic for the breast cancer cell line MCF-7. In this study, we aimed to examine the effect of MA1 on human ovarian cancer cells. The potential cytotoxicity of MA1was tested on cisplatin-sensitive (A2780S) and cisplatin-resistant (A2780CP) ovarian cancer cell lines using AlamarBlue assay, Hoechst dye, flow cytometry, Western blot, and RT-qPCR. MA1 had higher cytotoxic activity on A2780S (IC50 = 0.23 µM) and A2780CP (IC50 = 0.34 µM) cell lines when compared to cisplatin (IC50 = 31.4 µM and 76.9 µM, respectively). Flow cytometry analysis confirmed the cytotoxic effect of MA1. The synergistic effect of the two drugs was obvious, since only 13% of A2780S and 7% of A2780CP cells remained alive after 24 h of treatment with both MA1 and cisplatin. Moreover, we examined the expression of bcl2, p53, caspase3/9 genes at RNA and protein levels using RT-qPCR and Western blot, respectively, to figure out the cell death mechanism induced by MA1. A significant down-regulation in bcl2 and p53 genes was observed in treated cells compared to non-treated cells (p < 0.05), suggesting that MA1 may not follow the canonical pathway to induce apoptosis in ovarian cancer cell lines. MalforminA1 showed promising anticancer activity by inducing cytotoxicity in cisplatin-sensitive and cisplatin-resistant cancer cell lines. Interestingly, a synergistic effect was observed when MA1 was combined with cisplatin, leading to it overcoming its resistance to cisplatin.     

Reversible Lysine Modification on Proteins by Using Functionalized Boronic Acids

Iminoboronates have been utilized to successfully install azide and alkyne bioorthogonal functions on proteins, which may then be further reacted with their bioorthogonal counterparts. These constructs were also used to add polyethylene glycol (PEG) to insulin, a modification which has been shown to be reversible in the presence of fructose. Finally, iminoboronates were used to assemble a folic acid/paclitaxel small‐molecule/drug conjugate in situ with an IC₅₀ value of 20.7 nM against NCI‐H460 cancer cells and negligible cytotoxicity against the CRL‐1502 noncancer cells.     

Non-alkaloids extract from Stemona sessilifolia enhances the activity of chemotherapeutic agents through P-glycoprotein-mediated multidrug-resistant cancer cells

One of the major impediments to the successful treatment of cancer is the development of resistant cancer cells, which could cause multidrug resistance (MDR), and overexpression of ABCB1/P-glycoprotein (P-gp) is one of the most common causes of MDR in cancer cells. Recently, natural products or plant-derived chemicals have been investigated more and more widely as potential multidrug-resistant (MDR) reversing agents. The current study demonstrated for the first time that non-alkaloids extract from Stemona sessilifolia significantly reversed the resistance of chemotherapeutic agents, adriamycin, paclitaxel and vincristine to MCF-7/ADR cells compared with MCF-7/S cells in a dose-dependent manner. The results obtained from these studies indicated that the non-alkaloids extract from S. sessilifolia plays an important role in reversing MDR of cancer as a P-gp modulator in vitro and may be effective in the treatment of multidrug-resistant cancers.     

alpha-Mangostin enhances betulinic acid cytotoxicity and inhibits cisplatin cytotoxicity on HCT 116 colorectal carcinoma cells

Despite the progress in colon cancer treatment, relapse is still a major obstacle. Hence, new drugs or drug combinations are required in the battle against colon cancer. α-Mangostin and betulinic acid (BA) are cytotoxic compounds that work by inducing the mitochondrial apoptosis pathway, and cisplatin is one of the most potent broad spectrum anti-tumor agents. This study aims to investigate the enhancement of BA cytotoxicity by α-mangostin, and the cytoprotection effect of α-mangostin and BA on cisplatin-induced cytotoxicity on HCT 116 human colorectal carcinoma cells. Cytotoxicity was investigated by the XTT cell proliferation test, and the apoptotic effects were investigated on early and late markers including caspases-3/7, mitochondrial membrane potential, cytoplasmic shrinkage, and chromatin condensation. The effect of α-mangostin on four signalling pathways was also investigated by the luciferase assay. α-Mangostin and BA were more cytotoxic to the colon cancer cells than to the normal colonic cells, and both compounds showed a cytoprotective effect against cisplatin-induced cytotoxicity. On the other hand, α-mangostin enhanced the cytotoxic and apoptotic effects of BA. Combination therapy hits multiple targets, which may improve the overall response to the treatment, and may reduce the likelihood of developing drug resistance by the tumor cells. Therefore, α-mangostin and BA may provide a novel combination for the treatment of colorectal carcinoma. The cytoprotective effect of the compounds against cisplatin-induced cytotoxicity may find applications as chemopreventive agents against carcinogens, irradiation and oxidative stress, or to neutralize cisplatin side effects.     

Targeting efficiency of a-1,3-galactosyl transferase gene in pig fetal fibroblast cells

Animal cloning technology with somatic cells provides an alternative tool to conventional methods for producing transgenic animals. Gene targeting in animals is made feasible using somatic cells with homologous recombination procedure that is a major technique in embryonic stem cells for knocking-out genes. Homologous recombination events in somatic cells are relatively inefficient as compared to those in ES cells, suggesting the need for establishment of efficient gene targeting system in somatic cells. To investigate the efficiency of positive and negative selection for gene targeting in pig fetal fibroblast cells, pig alpha-1,3-galactosyl transferase (13-GT) gene was used for gene targeting. The neomycin phosphotransferase (Neo(r)) and herpes simplex virus-thymidine kinase (HSV-tk) genes were used as positive and negative selection markers in this experiment. Following transfection with targeting DNA construct, the pig fetal fibroblast cells were selected against resistance of G418 and gancyclovir. In DMEM medium containing 5 to 10% serum, Pig fetal fibroblast cells failed to proliferate during drug selection. Increasing serum concentration to 15% of medium yielded less senescent colonies of pig fetal fibroblast cells following drug selection that allowed enough cell colonies to screen genomic DNA. The frequency of gene targeting in pig fetal fibroblast cells with double drug selection was more than 10-fold efficient compared to that with G418 single selection. Double selection method with Neo' and HSV-tk genes could be useful for gene targeting in somatic cells for production of cloned animals carrying targeted endogenous genes.     

A simple and fast microfluidic approach of same-single-cell analysis (SASCA) for the study of multidrug resistance modulation in cancer cells

Due to the cellular heterogeneity in multidrug resistance (MDR) cell populations, positive drug effects on the modulation of MDR can be obscured in conventional methods, especially when only a small number of cells are available. To address cellular variations among different MDR cells, we report a new microfluidic approach to study drug effect on MDR modulation, by investigating drug accumulation of daunorubicin in MDR leukemia cells. We have demonstrated that the new approach of same-single-cell analysis by accumulation (denoted as SASCA-A) is not only superior to different-single-cell analysis, but also has key advantages over our previous approach of same-single-cell analysis. First, SASCA-A is much simpler as it does not require multiple cycles of drug uptake and drug efflux. Second, it is faster, only taking about one fourth of the time used in the previous approach. Third, it provides a more 'identical' and reliable control because it compares the time points just before MDR modulator tests. To help understand the dynamics of drug accumulation in MDR cells, we also developed a mathematical model to describe the kinetics of drug accumulation conducted in individual cells. The SASCA-A method will benefit drug resistance research in minor cell subpopulations (e.g., cancer "stem" cells) because this method requires only a small number of cells in identifying the MDR reversal effect.     

Unique Use of Alkylation for Chemo‐Redox Activity by a PtIV Prodrug

Resistance towards chemotherapeutics displayed by cancer cells is a significant stumbling block against fruitful cisplatin‐based therapy. A unique dual‐acting chemotherapeutic modality, Platin‐B, a prodrug of cisplatin and pipobroman‐mimicking alkylating agent, was constructed to circumvent tumor resistance. Platin‐B exhibited a superior cytotoxicity profile in cisplatin‐resistant cancer cells. Enhanced activity and the ability to overcome cancer‐induced resistance of Platin‐B was related to adduct formation with intracellular glutathione, followed by the activity of Platin‐B on the mitochondria of cells, along with its conventional nuclear activity. Alkylating moieties present on Platin‐B enhanced its cellular and subcellular concentration and protected it from early drug sequestration by biological thiols.     

Epigenetic dysregulation of immune-related pathways in cancer: bioinformatics tools and visualization

Cancer immune evasion is one of the hallmarks of carcinogenesis. Cancer cells employ multiple mechanisms to avoid immune recognition and suppress antitumor immune responses. Recently, accumulating evidence has indicated that immune-related pathways are epigenetically dysregulated in cancer. Most importantly, the epigenetic footprint of immune-related pathways is associated with the patient outcome, underscoring the crucial need to understand this process. In this review, we summarize the current evidence for epigenetic regulation of immune-related pathways in cancer and describe bioinformatics tools, informative visualization techniques, and resources to help decipher the cancer epigenome.Subject terms: Genetics research, Biomarkers