Therapeutic Effect Of Anticancer Drugs Research Articles

Metabolomics analysis of multidrug-resistant breast cancer cells in vitro using methyl-tert-butyl ether method.

The comprehensive characterization of metabolome and lipidome to reveal unknown pathological conditions, are being used to investigate the molecular mechanisms of cancer, especially in the field of early diagnosis, treatment, and prognosis. The multidrug resistance (MDR) of tumor cells limits the therapeutic effect of anti-cancer drugs and is the main obstacle for chemotherapy. Here, we adopted a methyl-tert-butyl ether (MTBE)-based extraction method to simultaneously extract small polar molecules and lipophilic metabolites for nontargeted metabolomics of multidrug-resistant breast cancer cell line MCF-7/ADR and its parental cell line MCF-7/S by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Distinctly different metabolic features were shown between MCF-7/ADR cells and MCF-7/S on the basis of multivariate analyses. 17 potential biomarkers were identified. And these potential biomarkers were mainly correlated with cell membrane lipids composition, cell signaling regulated by lipids, and anti-oxidation ability. The studies of cellular ultrastructure and morphology by in situ atomic force microscopy (AFM) also demonstrated the cellular membrane changed along with the MDR. We expect that this study could provide a new method for monitoring drug resistance during clinical chemotherapy and be useful for the development of drugs to overcome the MDR.

Correlation of Reactive Oxygen Species Levels with Resveratrol Sensitivities of Anaplastic Thyroid Cancer Cells.

Anaplastic thyroid carcinoma (ATC) is the most lethal thyroid malignancy without a reliable therapeutic agent. Resveratrol possesses cancer-suppressive effects, while its effect(s) on ATC cells remains unknown. Because oxidative damage caused by increased reactive oxygen species (ROS) is one of the therapeutic effects of anticancer drugs and oxidative stress-caused mitochondria swelling is observed in resveratrol-treated cancer cells, the oxidative statuses and their relevance with resveratrol sensitivities are elucidated using THJ-16T and THJ-11T ATC cells established from two human anaplastic thyroid carcinoma cases. The results revealed that resveratrol-treated THJ-16T rather than THJ-11T cells showed remarkable growth arrest and extensive apoptosis accompanied with the elevated ROS generation and the attenuated superoxide dismutase 2 (SOD2) and catalase (CAT) levels. Mitochondrial impairment and the enhanced caspase-9/caspase-3 activation are found only in resveratrol-sensitive THJ-16T cells. Treatment with the antioxidant N-acetylcysteine (NAC) partly attenuated resveratrol-induced ROS generation and apoptosis of THJ-16T cells. The levels of resveratrol metabolic enzymes (SULT1A1 and SULT1C2) in THJ-16T cells were lower than those in THJ-11T cells and therefore reversely related with resveratrol sensitivities of ATC cells. Our findings demonstrate the ability of resveratrol to increase ROS generation and oxidative-related cellular lesions in resveratrol-sensitive THJ-16T cells presumably through activating the ROS-mitochondrial signal pathway. The levels of SULTs and ROS may reflect the response manners of ATC cells to resveratrol.

Modulation of Mcl-1 transcription by serum deprivation sensitizes cancer cells to cisplatin

BackgroundThe development of approaches that increase therapeutic effects of anti-cancer drugs is one of the most important tasks of oncology. Caloric restriction in vivo or serum deprivation (SD) in vitro has been shown to be an effective tool for sensitizing cancer cells to chemotherapeutic drugs. However, the detailed mechanisms underlying the enhancement of apoptosis in cancer cells by SD remain to be elucidated. MethodsFlow cytometry, caspase activity assay and western blotting were used for cell death rate evaluation. Western blotting, gel-filtration, siRNA approach and qRT-PCR were used to elucidate the mechanism underlying cell death potentiation upon SD. ResultsWe demonstrated that SD sensitizes cancer cells to treatment with chemotherapeutic agent cisplatin. This effect is independent on activation of caspases-2 and -8, apical caspases triggering apoptosis in response to genotoxic stress. SD potentiates cell death via downregulation of the anti-apoptotic protein Mcl-1. In fact, SD reduces the Mcl-1 mRNA level, which consequently decreases the Mcl-1 protein level and renders cells more susceptible to apoptosis induction via the formation of apoptosome. ConclusionsMcl-1 protein is an important regulator of sensitivity of cancer cells to apoptotic stimuli upon SD. General significanceThis study identifies Mcl-1 as a new target for the sensitization of human cancer cells to cell death by SD, which is of great significance for the development of efficient anti-cancer therapies.

Dual inhibition of P-glycoprotein and midkine may increase therapeutic effects of anticancer drugs

Multidrug resistance (MDR) to chemotherapy may significantly affect the outcome of cancer treatment. ATP-dependent drug efflux pumps, including P-glycoprotein (P-gp), contribute to the resistance of various chemotherapeutic agents. Overexpression of P-gp in tumor cells induces chemoresistance via pumping the anticancer drugs out of the cells. In addition to taking part in many biological processes such as development, reproduction and repair, midkine (MK) also plays important roles in the pathogenesis of malignant diseases as well as in the regulation of MDR. Although, the mechanisms of action of P-gp and MK are different, overexpression of both proteins prevents the accumulation of many chemotherapeutics in tumor cells, leading to decreased therapeutic effects of anticancer drugs. Therefore, identification of the result of dual inhibition of P-gp and MK in overcoming chemoresistance may enhance the likelihood for a more efficient chemotherapy.

PH and redox dual-responsive biodegradable polymeric micelles with high drug loading for effective anticancer drug delivery

Diblock copolymers of poly(ethylene glycol) (PEG) and biodegradable polycarbonate functionalized with GSH-sensitive disulfide bonds and pH-responsive carboxylic acid groups were synthesized via organocatalytic ring-opening polymerization of functional cyclic carbonates with PEG having different molecular weights as macroinitiators. These narrowly-dispersed polymers had predictable molecular weights, and were used to load doxorubicin (DOX) into micelles primarily through ionic interactions. The DOX-loaded micelles exhibited the requisite small particle size (<100 nm), narrow size distribution and high drug loading capacity. When exposed to endolysosomal pH of 5.0, drug release was accelerated by at least two-fold. The introduction of GSH further expedited DOX release. Effective DOX release enhanced cytotoxicity against cancer cells. More importantly, the DOX-loaded micelles with the optimized composition showed excellent antitumor efficacy in nude mice bearing BT-474 xenografts without inducing toxicity. These pH and redox dual-responsive micelles have the potential as delivery carriers to maximize the therapeutic effect of anticancer drugs.

Enhanced Antitumor Activity of EGFP-EGF1-Conjugated Nanoparticles by a Multitargeting Strategy.

Tumor stromal cells have been increasingly recognized to interact with tumor parenchyma cells and promote tumor growth. Therefore, we speculated that therapeutics delivery to both parenchyma cells and stromal cells simultaneously might treat a tumor more effectively. Tissue factor (TF) was shown to be extensively located in a tumor and was abundantly sited in both tumor parenchyma cells and stromal cells including neo-vascular cells, tumor-associated fibroblasts, and tumor-associated macrophages, indicating it might function as a favorable target for drug delivery to multiple cell types simultaneously. EGFP-EGF1 is a fusion protein derived from factor VII, the natural ligand of TF. It retains the specific TF binding capability but does not cause coagulation. In the present study, a nanoparticle modified with EGFP-EGF1 (ENP) was constructed as a multitargeting drug delivery system. The protein binding experiment showed EGFP-EGF1 could bind well to A549 tumor cells and other stromal cells including neo-vascular cells, tumor-associated fibroblasts, and tumor-associated macrophages. Compared with unmodified nanoparticles (NP), ENP uptake by A549 cells and those stromal cells was significantly enhanced but inhibited by excessive free EGFP-EGF1. In addition, ENP induced more A549 tumor cell apoptosis than Taxol and NP when paclitaxel (PTX) was loaded. In vivo, ENP accumulated more specially in TF-overexpressed A549 tumors by in vivo imaging, mainly regions unoccupied by factor VII and targeted tumor parenchyma cells as well as different types of stromal cells by immunofluorescence staining. Treatment with PTX-loaded ENP (ENP-PTX) significantly reduced the A549 tumor growth in nude mice while NP-PTX- and Taxol-treated mice had lower response to the therapy. Furthermore, H&E and TUNEL staining revealed that ENP-PTX induced more severe tumor necrosis and more extensive cell apoptosis. Altogether, the present study demonstrated that ENP could target multiple key cell types in tumors through TF, which could be utilized to improve the therapeutic effect of anticancer drugs.

MicroRNA-509-3p increases the sensitivity of epithelial ovarian cancer cells to cisplatin-induced apoptosis.

XIAP is upregulated in chemoresistant epithelial ovarian cancer (EOC). However, the molecular mechanism of this dysregulation remains unclear. The regulation of XIAP by miR-509-3p was investigated by luciferase reporter assay, real-time PCR and immunobloting, and the roles of miR-509-3p in cellular proliferation and apoptosis were accessed through MTT and DAPI assays. miR-509-3p, a downregulated miRNA in chemoresistant EOC, can directly target the XIAP via its 3'UTR. Overexpression of miR-509-3p can not only downregulate the expression of XIAP in ovarian cancer cells but also inhibit the proliferation of EOC cells and increase their sensitivity to cisplatin-induced apoptosis. Our data suggest that restoring certain dysregulated miRNAs to their normal levels could increase the therapeutic effects of anticancer drugs.

PH-Sensitive Docetaxel-Loaded d-α-Tocopheryl Polyethylene Glycol Succinate–Poly(β-amino ester) Copolymer Nanoparticles for Overcoming Multidrug Resistance

Multidrug resistance (MDR) is one of the major obstacles to successful chemotherapy. Overexpression of drug efflux transporters such as P-glycoprotein (P-gp) is an important factor responsible for MDR. Herein, a novel copolymer, D-α-tocopheryl polyethylene glycol 1000-block-poly(β-amino ester) (TPGS-b-PBAE, TP), was synthesized for overcoming multidrug resistance by the synergistic effect of the pH-sensitive behavior of PBAE and P-gp inhibiting activity of TPGS. Docetaxel (DTX) was chosen as the model drug. The resulting DTX-loaded nanoparticles were stable at pH 7.4, while they dissociated in a weakly acidic environment (pH 5.5) and released the incorporated DTX quickly. The DTX-loaded TP nanoparticles increased the cell cytotoxicity against both drug-sensitive human ovarian A2780 and drug-resistant A2780/T cells. The IC(50) of DTX-loaded TP against A2780/T cells was 100-fold lower than that of commercial DTX. This was associated with enhanced DTX-induced apoptosis and cell arrest in the G2/M phase. Furthermore, P-gp inhibition assays, including enhancement of the fluorescence intensity of rhodamine 123 and reduction of the intracellular ATP levels, confirmed the P-gp inhibition nature of the TP copolymer. The use of the TP copolymer is a new approach to improve the therapeutic effect of anticancer drugs in MDR tumors.

Recent discoveries in the cycling, growing and aging of the p53 field

The P53 gene and it product p53 protein is the most studied tumor suppressor, which was considered as oncogene for two decades until 1990. More than 60 thousand papers on the topic of p53 has been abstracted in Pubmed. What yet could be discovered about its role in cell death, growth arrest and apoptosis, as well as a mediator of the therapeutic effect of anticancer drugs. Still during recent few years even more amazing discoveries have been done. Here we review such topics as suppression of epigenetic silencing of a large number of non-coding RNAs, role of p53 in suppression of the senescence phenotype, inhibition of oncogenic metabolism, protection of normal cells from chemotherapy and even tumor suppression without apoptosis and cell cycle arrest.

Using Activated Carbon Nanoparticles to Decrease the Genotoxicity and Teratogenicity of Anticancer Therapeutic Agents

One of the key obstacles against the success in cancer chemotherapy is the toxic and side effects of the chemotherapeutic agents. The avoidance of these toxic and side effects will greatly improve the therapeutic effects of anticancer drugs while decrease the pains of the patients. Here we show that activated carbon nanoparticles (ACNP), one of the mesoporous nanoparticles, can decrease the genotoxicity and teratogenicity of mitomycin C (MMC). To study the effects of ACNP on genotoxicity and teratogenicity of MMC, methods of PCE micronucleus test, Chinese hamster lung cell chromosome aberration experiment and rat teratogenicity were employed to observe the differences in genotoxicity and teratogenicity between ACNP-adsorbed MMC (ACNP-MMC) and free MMC. Results demonstrated that free MMC 0.16-5.0 microg/kg significantly increased the positive rate of PCE micronucleus test, the chromosome aberration rate and rat teratogenecity, but ACNP-MMC did not increased these heredity and reproduction toxicological indexes in a dose range of 0.625-10.0 microg/kg. From these results, it can be concluded that ACNP-MMC have significant effects to decrease the genotoxicity and teratogenicity effects of MMC. These results will have a considerable impact on the strategy of anticancer chemotherapy.

Transarterial Chemoembolization With Degradable Starch Microspheres, Irinotecan, and Mitomycin-C in Patients With Liver Metastases

Degradable starch microspheres (DSMs) provide transient occlusion of small arteries and are thought to improve the therapeutic effect of anticancer drugs. Irinotecan (CPT-11) is one of the most effective anticancer agents. We herein report cases with liver metastases treated with transarterial chemoembolization with DSM, CPT-11, and mitomycin-C (DSM-CPT therapy). Five patients underwent DSM-CPT therapy for liver metastases that originated from colorectal cancer for four and gastric cancer for one. They all lack indication for surgery. They were all male with an age range of 42-78 years (mean, 55.2 years). Three of them had pretreatment histories with 5-fluorouracil or related agents, and four of them had combined systemic or local chemotherapy at the period. Required doses for stasis of whole blood flow of hepatic artery of DSMs were used with CPT-11 and mitomycin-C. After one to six injections, four patients had a partial response and the disease progressed in one patient with gastric cancer origin. Two of the partial response patients underwent surgery after 2 months of the partial response period. Carcinoembryonic antigen and CA19-9 levels in partial response patients decreased to 16.1% and 19.3% of the level before treatment, respectively. DSM-CPT therapy can be a potential therapy for liver metastases.

Functional Analysis of a Cation Transporter OCT6: A Mediator of the Cellular Influx of Adriamycin.

(Introduction) It is necessary for killing leukemic cells effectively to achieve a sufficient intracellular concentration of anti-cancer drugs. To date, overexpression of efflux pump such as MDR-1 and MRP-1, which leads to a decrease of cellular concentration of drugs, has been shown to attenuate the therapeutic effect of anti-cancer drugs and correlate with low remission rate in acute leukemia. If the expression of genes, which import anti-cancer drugs, can be induced specifically in leukemic cells, it would lead to an increase of intracellular concentration, resulting in an enhancement of the pharmacological effect. In this study, we performed the pharmacological characterization of a cation transporter gene, OCT6, and explore the possibility of its application for anti-cancer therapy.(Methods) Tissue distribution of OCT6 was examined by Northern blot analysis. Expression in clinical samples that consist of 34 patients; 15 patients with acute lymphoblastic leukemia (ALL), 17 patients with acute myelogenous leukemia (AML), 2 patients with chronic myelogenous leukemia (CML) in blastic crisis, was examined by quantitative RT-PCR. The percentage of blasts in each sample was above 80%. For functional analysis, OCT6 cRNA was injected into Xenopus oocytes and pharmacological analysis was performed. In order to examine the transporting activity in hematopoietic cells, we established subclones of Jurkat, a T lymphocytic leukemia cell line, in which OCT6 gene is constitutively expressed, and the change of the sensitivity for adriamycin was examined.(Result) By Northernblot analysis, 2.4kb OCT6 mRNA was detected in testis and bone marrow in adult tissues. OCT6 expressed in Xenopus oocytes transported not only tetraethlammonium but also adriamycin in a saturable and dose-dependent manner. The apparent Km value for [14C] adriamycin was 5.2±0.4μM. On the other hand, OCT6 did not transport either of methotrexate (MTX) and 5-fluorouracil (5-FU), which are not organic cations. After the exposure of adrimycin at the therapeutic concentration, the viability of OCT6 overexpressing Jurkat cells was significantly decreased compared to that of control cells. Consistent with this, the percentage of apoptosis cells became higher than that of control cells. When the expression level was examined in clinical samples, the average of the levels of patients was comparable to PBMCs. The level of patients, who achieved with complete remission (CR), was slightly higher than that of patients with non-response (NR), but the difference was not significant. Some patients exhibited the high expression of OCT6, but the distribution did not deviated to either CR or NR group.(Conclusion) These results suggest that the induction of OCT6 in leukemic cells might be a novel strategy for leukemia treatment.

Clinical evaluation of urinary 6-hydroxymethylpterin (6-HMP) in patients with cancer of the digestive organs

The purpose of this study is to clarify the clinical significance of urinary 6-HMP in patients with cancer of the digestive organs. High-performance liquid chromatography (HPLC) was used to determine 6-HMP in first morning urine. Conclusions were as follows: 1. Cut off level of urinary 6-HMP was defined as 0.079 μg/ml, from 87 normal subjects. 2. The daily profile of urinary 6-HMP in normal subjects was highest in morning and lowest at bedtime and daily changes were continuously under the cut off level. 3. Sensitivity, specificity and accuracy of urinary 6-HMP were 64.2%, 77.6% and 70.5% respectively. 4. In patients with malignant diseases, the overall positive rate was 64.2% and was clearly higher than benign diseases. 5. The positive rate of urinary 6-HMP levels in malignant diseases was highest in pancreatic cancer (75.0%) and lowest in hepatocellular carcinoma (55.8%). 6. Urinary 6-HMP elevated several days after operation and returned within normal range after 2–3 weeks. 7. Urinary 6-HMP concentration correlated to the therapeutic effects of anticancer drugs, and increased again in tumor recurrence.

Theta-class glutathione S-transferases in human kidney and renal tumours.

Glutathione S-transferases are a family of dimeric multi-functional enzymes involved in the cellular detoxification and excretion of endogenous substances and xenobiotics. The theta-class of GSTs is composed of two homodimeric isoenzymes designated GSTTl-I[ I] and GSTT2-2 [2]. GSTs are thought to be involved in the sensitivity of tumours to the therapeutic effects of anticancer drugs. It is therefore important to characterize the level of expression of these enzymes in both normal and neoplastic tissues. This is especially important in renal tissue since renal tumonrs are particularly refractory to chemotherapy. Cytosolic proteins f?om normal cortex and matched tumour tissues from nephrectomy patients (n=31) were resolved using a 15% SDS-PAGE system and transferred to nitrocellulose membranes using standard procedures. Theta-class GST expression was determined by directing primary antibodies against GSTTl-1[3] (monoclonal) and GSTT2-2 [4] (polyclonal) respectively. Membranes were subsequently incubated with HRP-conjugated secondary antibodies, rabbit anti-mouse Ig (GSTTI-I) and goat anti-rabbit Ig (GSTT2-2) and visualised using DAB. lmmunohistochemical localisation of theta-class GSTs was determined using the SABC-AP system.

Effects of Anthracyclines on Cellular Differentiation and Oncogene Expression: Implications for Carcinogenesis and Cancer Chemotherapy

Regulation of cellular differentiation has been suggested to play a major role in the mechanisms of chemical carcinogenesis as well as in the therapeutic effects of anticancer drugs . Therefore , the establishment of differentiation assays appears important in oncology research . Leukemic cell lines have been used as experimental models to study the differentiation-inducing effect of cytostatic compounds in neoplastic cells . Experiments with anthracycline antibiotics in Friend erythroleukemia cells and HL-60 cells showed 1] a structure-specific induction of differentiation and 2] an early differentiation-specific down-regulation of c-myc and c-myb mRNA levels. These results suggest that the induction of differeniation by anthracyclines occurs through specific biochemical mechanisms and that increased cell maturation is not based on a general suppression of cell proliferation. Therefore, the specific induction of differentiation in certain leukemic cells may be a therapeutic advantage of differentiation -inducing anthracyclines such as aclacinomycin A and related compounds.

Prediction of the maximal tolerated dose (MTD) and therapeutic effect of anticancer drugs in humans: integration of pharmacokinetics with pharmacodynamics and toxicodynamics

Prediction of the maximal tolerated dose (MTD) and therapeutic effect of anticancer drugs in humans: integration of pharmacokinetics with pharmacodynamics and toxicodynamics

Detection and characterization of residual disease in breast cancer.

Although micrometastatic tumor cell spread largely determines the prognosis of patients with operable breast cancer, it is usually missed by conventional tumor staging. Several groups (including ours) have therefore developed immunocytochemical and molecular assays that allow the specific detection and characterization of individual carcinoma cells disseminated to bone marrow, blood, and lymph nodes. These assays may improve the prognostic precision of the current classification systems and may provide a tool for the early assessment of the therapeutic effects of anticancer drugs on micrometastatic cells in individual patients. Another aspect of such methods is that they enable detection of tumor cell contamination in stem cell grafts and validation of the efficiency of purging techniques. The most extensive experience exists with immunocytochemical methods, some of which have the potential to serve as a benchmark for less validated molecular methods. Still, the specificity and sensitivity of immunocytochemical detection of single cancer cells are affected by several variables, which include the intricacies of antigen expression, the lack of distinct morphological characteristics, the size of the analyzed sample, and the staining techniques for visualization of antibody binding. This article provides a critical review of the opportunities and pitfalls related to new methods for the detection and monitoring of minimal residual disease in breast cancer.

Dose-dependent metabolism, therapeutic effect, and toxicity of anticancer drugs in man.

Dose-dependent metabolism is seen for a number of anticancer drugs, and they provide examples of several different types of dose-dependent metabolic processes. Arabinosyl cytosine and 5-fluorouracil are drugs whose catabolism is saturated at high doses. Therapeutic response to both drugs has been linked to plasma concentration of parent compound, and a nonlinear dose-response relationships might exist at high doses. L-Alanosine also appears to exhibit saturable metabolism at high doses, and this might be responsible for the rapid onset of L-alanosine toxicity as the dose is increased. Isophosphamide is a drug which requires metabolic activation to exert its biological effect, and saturation of metabolism seen at high dose could lead to a plateau in the dose-response relationship. Thymidine exhibits saturation of metabolism at high doses due in part to product inhibition of metabolism. Product inhibition of metabolism has also been suggested for arabinosyl cytosine. Plasma elimination of thymidine and possible elimination of 6-diazo-5-oxo-L-norleucine exhibit characteristics of a dose-dependent "memory" effect. Dose-dependent metabolism of methotrexate is unusual in that formation of the presumed toxic metabolite increases with increase in dose and is associated with a qualitative change in the pattern of drug toxicity at high compared to low doses of drug. The relationship between dose and toxicity of drugs and other foreign compounds is poorly understood in man. Anticancer drugs are one of the few classes of compounds where the relationship of toxicity to dose is reasonably well documented in human subjects. Saturation of metabolism leading to dose-dependent pharmacokinetics occurs with several anticancer drugs, and different types of dose-dependent metabolism have been covered in this review. An attempt has been made to show how dose-dependent metabolism of anticancer drugs might relate to their toxicity. Principles of dose-dependent toxicity seen with anticancer drugs might usefully be applied to other classes of compounds, particularly compounds exhibiting cytotoxicity but also other forms of toxicity. Dose-dependent metabolism could also be important in determining the therapeutic effect of anticancer drugs, and application of principles of dose-dependent metabolism to the development of new chemotherapeutic regimens migh lead to more effective cancer chemotherapy.