Targeting therapy with mitosomal daunorubicin plus amlodipine has the potential to circumvent intrinsic resistant breast cancer

Intrinsic resistance of cancers is a major cause of failure in chemotherapy. We proposed here a strategy to overcome intrinsic resistance by constructing cancer cell mitochondria-specifically targeting drug-loaded liposomes, namely, mitosomal daunorubicin plus amlodipine. Anticancer agent daunorubicin and apoptotic inducer amlodipine were loaded together into the mitosomes, and targeting molecule dequalinium was modified on the surface. Evaluations were performed on the breast cancer MCF-7 and resistant MCF-7/adr cells and in animals. Mitosomal daunorubicin plus amlodipine were about 97 nm, selectively accumulated in mitochondria, induced the swelling and disruption of mitochondria, dissipated the mitochondrial membrane potential, released a large amount of cytochrome C by translocation, cleaved Bid, and initiated a cascade of caspase 8 and 3 reactions. A robust anticancer effect was evidenced in vivo. Mitochondria-specifically targeting drug-loaded liposomes would provide a new strategy for treating resistant cancers.     

mPEG-b-PCL/TPGS mixed micelles for delivery of resveratrol in overcoming resistant breast cancer

Objective: Drug resistance remains a major challenge for effective breast cancer chemotherapy. Resveratrol (Res) is a promising candidate for overcoming cancer chemoresistance, but it has low bioavailability due to poor absorption, and ready metabolism limits its application. This study aims to develop a Res-loaded mixed micelle system to be effective on drug resistance of breast cancer cells.

Methods: A mixed micelle system made of methoxy poly (ethylene glycol)-b-polycaprolactone (mPEG-PCL) and d-α-Tocopherol polyethylene glycol succinate was prepared and Res was encapsulated to form Res-loaded mixed micelles. Furthermore, the antitumor activity against doxorubicin (Dox)-resistant breast cancer MCF-7/ADR cells was studied and the possible mechanism was elucidated.

Results: The mixed micellar formulation increased drug uptake efficiency of Res by Dox-resistant breast cancer MCF-7/ADR cells, and induced higher rates of apoptotic cell death, as assessed by the accumulation of Sub G1 phases of cell cycle, nucleus staining and Annexin-FITC/propidium iodide assay. Moreover, Res-loaded mixed micelles also markedly enhanced Dox-induced cytotoxicity in MCF-7/ADR cells and increased the cellular accumulation of Dox by downregulating the expression of P-glycoprotein (P-gp) and inhibiting the activity thereof.

Conclusion: The cumulative evidence indicates that Res-loaded mixed micelles hold significant promise for the treatment of drug-resistant breast cancer.     

Saikosaponin A,an active glycoside from Radix bupleuri,reverses P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cells and HepG2/ADM cells

1.?The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multidrug resistance (MDR). Saikosaponin A (SSA) is a triterpenoid saponin isolated from Radix Bupleuri. This study was mainly designed to understand effects of SSA on MDR in MCF-7/ADR and HepG2/ADM cells.

2.?MDR reversal was examined as the alteration of cytotoxic drugs IC50 in resistant cells in the presence of SSA by MTT assay, and was compared with the non-resistant cells. Apoptosis and uptake of P-gp substrates in the tumor cells were detected by flow cytometry. Western blot was performed to assay the expression of P-gp.

3.?Our results demonstrate SSA could increase the chemosensitivity of P-gp overexpressing HepG2/ADM and MCF-7/ADR cells to doxorubicin (DOX), vincristine (VCR) and paclitaxel. SSA promoted apoptosis of MCF-7/ADR cells in the presence of DOX. Moreover, it could also increase the retention of P-gp substrates DOX and rhodamine 123 in MCF-7/ADR cells, and decrease digoxin efflux ratio in Caco-2 cell monolayer. Finally, a mechanistic study showed that SSA reduced P-gp expression without affecting hydrolytic activity of P-gp.

4.?In conclusion, our findings suggest that SSA could be further developed for sensitizing resistant cancer cells and used as an adjuvant therapy together with anticancer drugs to improve their therapeutic efficacies.     

Hyaluronic acid modified daunorubicin plus honokiol cationic liposomes for the treatment of breast cancer along with the elimination vasculogenic mimicry channels

Background: Breast cancer is an alarming global public health problem and a main cause of cancer-related death in women. Systemic chemotherapy is the most widely used treatment for breast cancer. However, current chemotherapy treatments are far from desirable due to poor targeting specificity, severe side effects and vasculogenic mimicry (VM).

Purpose: Hyaluronic acid (HA)-modified daunorubicin plus honokiol (HNK) cationic liposomes were prepared and characterised for treatment of breast cancer by eliminating VM.

Methods: HA-modified daunorubicin plus HNK cationic liposomes were prepared by a thin-film hydration method. Evaluations were performed on MCF-7 cells and MDA-MB-435S cells, which are human breast cancer cells, and xenografts of MDA-MB-435S cells.

Results: In vitro results revealed that the HA-modified daunorubicin plus HNK cationic liposomes enhanced the cellular uptake and destroyed VM channels. In vivo results demonstrated that the liposomes prolonged the circulation time in the blood, obviously accumulated in the tumour region, and enhanced the overall anticancer effects. Action mechanisms were related to down-regulation of VM protein indicators including FAK, EphA2, MMP-2 and MMP-9.

Conclusions: The prepared HA-modified daunorubicin plus HNK cationic liposomes may serve as a promising therapeutic strategy for the treatment of breast cancer.     

Improvement of cytotoxic and apoptogenic properties of crocin in cancer cell lines by its nanoliposomal form

Objective: Saffron Crocus sativus L. (Iridaceae) is known for anticancer properties. However, limited effort has been made to correlate these effects to the active ingredients of saffron. In the present study, cytotoxic effects of crocin, the major coloring compound in saffron, and its nanoliposomal form for better cellular delivery are investigated.

Methods: HeLa and MCF-7 cells were cultured and exposed to crocin (1, 2, and 4?mM) and liposomal crocin (0.5 and 1?mM). The 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to assess cytotoxicity. Apoptotic cells were determined using propidium iodide (PI) staining of DNA fragmentation by flow cytometry.

Results: MTT assay revealed a remarkable and concentration-dependent cytotoxic effect of crocin on HeLa and MCF-7 cells in comparison with non-malignant cell line (L929). Crocin liposomal forms (IC₅₀ values after 48 h: 0.61, 0.64, and 1.2?mM) showed enhanced cytotoxic effect compared with the crocin (IC₅₀ after 48 h: 1.603?mM) in HeLa cells. Crocin and its liposomal form induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptosis is involved in this toxicity. Liposomal encapsulation enhances apoptogenic effects of crocin on cancerous cells.

Conclusion: It might be concluded that crocin and its liposomes could cause cell death in HeLa and MCF-7 cells, in which liposomal encapsulation improved cytotoxic effects. They could be also considered as a promising chemotherapeutic agent in cancer treatment in future.     

Simultaneous Modulation of Multidrug Resistance and Antiapoptotic Cellular Defense by MDR1 and BCL-2 Targeted Antisense Oligonucleotides Enhances the Anticancer Efficacy of Doxorubicin

Purpose. To enhance the anticancer efficacy of an established drug by the simultaneous suppression of pump and nonpump cellular resistance. Methods. Multidrug resistant human ovarian (A2780/AD) and breast (MCF-7/AD) cancer cells were used. Doxorubicin (DOX) and antisense oligonucleotides (ASO) targeted to MDR1 and BCL-2 mRNA were combined in a solution within one liposomal drug delivery system (LDDS) in different combination series. Ten series of experiments were performed. In each series cells were incubated with 12 to 45 concentrations of free DOX and different liposomal formulations over a period of 6 to 48 h. Cytotoxicity, apoptosis induction, caspases, MDR1, BCL-2, and APAF-1 genes, P-glycoprotein, and BCL-2 protein were studied. Results. The combination of DOX and ASO targeted to MDR1 and BCL-2 mRNA in one LDDS exhibited a dramatic increase in the anticancer action of DOX. As a result of the simultaneous suppression of pump and nonpump cellular resistance by the inhibition of P-glycoprotein and BCL-2 protein synthesis, a significant increase in the activation of caspases and apoptosis was observed. Conclusions. The simultaneous suppression of multidrug resistance and antiapoptotic cellular defense significantly enhanced the anticancer activity of DOX. Therefore, the proposed DDS combination may potentially be used in the treatment of multidrug-resistant ovarian and breast cancers.     

PEGylated VRB plus quinacrine cationic liposomes for treating non-small cell lung cancer

Background: Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, and the treatment effects are usually unsatisfactory. Vinorelbine (VRB) is extensively used in cancer treatment, but it has some disadvantages when used alone. PEGylated liposomes have been extensively used as a delivery carrier for antitumor drugs via prolonging the circulation time in the blood.

Purpose: The nanostructured liposomes were designed and prepared for treating NSCLC.

Methods: In the liposomes, PEG was modified on the liposomal surface, DC-Chol was used as cationic materials, and VRB plus quinacrine were encapsulated in an aqueous core of the liposomes as an antitumor drug and an apoptosis-inducing agent, respectively. Evaluations were performed on A549 cells, tubular network formations and xenografts of the A549 cells.

Results: The PEGylated drugs-loaded cationic liposomes could significantly enhance cellular uptake and selectively accumulate in A549 cells, thus leading to show strongest antitumor efficacy to tumor cells and to tumor-bearing mice. Action mechanisms showed that the enhanced efficacy in treating NSCLC was related to activate caspase 9 and caspase 3, to activate Bax and P53, and to suppress Bcl-2 and Mcl-1.

Conclusion: The PEGylated VRB plus quinacrine cationic liposomes showed a potential strategy for treating NSCLC.     

耐药乳腺癌裸鼠模型免疫治疗初探

目的 耐药乳腺癌表现为治疗效果差,转移率高,死亡率高的一种恶性程度极高的肿瘤性疾病。有研究表明,细胞因子诱导的杀伤细胞（CIK）在树突细胞（DC）辅助下,对耐药肿瘤细胞的杀伤能力可能超过T细胞。本实验利用DC与CIK联合培养,比较在不同条件下对乳腺癌多药耐药细胞株的杀伤效应。 方法 分离健康人外周血获得单个核细胞,分别诱导为树突细胞（DC）和CIK细胞,将人类乳腺癌耐药细胞株MCF-7/ADR细胞的冻融物抗原冲击DC（AP-DC）,分别将DC与CIK细胞共培养（AP-DC+CIK 、DC+CIK）,CIK细胞单独培养作对照。用流式细胞仪分析细胞表型,酶联免疫吸附法（ELISA）测定分泌IL-12、TNF-α、IFN-γ和IL-2水平,MTT法测定细胞毒效应。结果 DC和CIK细胞共孵育,使CIK细胞的CD3CD56双阳性细胞的比例及分泌IFN-γ、TNF-α和IL-2的水平增高,DC的成熟表型和分泌IL-12的水平增加,其中均以AP-DC+CIK组增高最为明显,和其他组间比较差异有统计学意义。对乳腺癌耐药细胞MCF-7/ADR的细胞毒效应,AP-DC+CIK组杀伤效应最强, 与DC+CIK组和CIK组比较差异均有统计学意义;结论 经耐药肿瘤抗原负载的DC与CIK共同作用后,其对耐药乳腺癌细胞MCF-7/ADR的抗瘤免疫能力最强,为临床治疗耐药肿瘤带来希望。     

Novel anticancer alkene lactone from Persea americana

Abstract

Context: Persea americana Mill (Lauraceae) root bark is used in ethnomedicine for a variety of diseases including cancer.

Objective: To isolate and characterize the chemical constituent in P. americana, and also to determine the anticancer property of a new alkene lactone from the root bark of P. americana.

Materials and methods: The MCF-7 cells were treated with different concentrations of the pure compound for 48?h. The percentage of cells in the various phases, online monitoring of metabolic changes and integrin receptor expression determined by flow cytometry.

Results: One novel alkene lactone (4-hydroxy-5-methylene-3-undecyclidenedihydrofuran-2 (3H)-one) (1) was isolated and characterized using 1D-NMR, 2D-NMR, infrared, UV and MS. At a concentration of 10?µg/mL, significant reduction of proliferation of MCF-7 was induced while MCF-12?A cell was significantly stimulated by 10?µg/mL. The IC₅₀ value for MCF-7 cells is 20.48?µg/mL. Lower concentration of 1 harbor no significant effect on either MCF-7 or MCF-12A. The apoptotic rates of MCF-7 cells were increased significantly. At the final concentration 10?µg/mL, up to 80% of all breast cancer cells were dead. On the non-tumorigenic cell line MCF-12A, the same concentrations (1 and 10?µg/mL) of compound 1 caused significant enhanced apoptotic rates. A total of 1?µg/mL of 1 caused a decrease of α4-, α6-, β1- and β3-integrin expression.

Conclusions: The compound caused a stimulatory effect on non-tumorigenic MCF-12A cells with respect to cell adhesion while tumorigenic MCF-7 cells detached continuously. This is the first report on the anticancer effects of this class of compound.     

TPGS修饰脂质体对阿霉素抗肿瘤活性的增敏作用

目的制备聚乙二醇1000维生素E琥珀酸酯(TPGS)修饰的阿霉素脂质体并考察其对阿霉素抗肿瘤活性的增敏作用。方法用阳离子树脂吸附法测定阿霉素脂质体的包封率;MTT法测定对MCF-7和MCF-7/ADR的毒性;用荧光显微镜观察阿霉素的细胞摄取,并用HPLC测定细胞内的阿霉素含量。结果 TPGS修饰的阿霉素脂质体增加了MCF-7/ADR对阿霉素的摄取,并增强了对MCF-7和MCF-7/ADR细胞的毒性。结论 TPGS修饰脂质体能显著增强MCF-7和MCF-7/ADR对阿霉素的敏感性。     

Emodin induces cytotoxic effect in human breast carcinoma MCF-7 cell through modulating the expression of apoptosis-related genes

Abstract

Context: The poor prognostic outcome of breast cancer is largely due to its resistance to cancer therapies. Development of therapeutic agents that can inhibit growth and induce apoptosis in breast cancer cells can help solve the problem. Emodin is an active anthraquinone that has been reported to have diverse biological effects.

Objective: In this study, the anticancer effects of emodin on growth inhibition, apoptosis induction and the expression of apoptosis-related genes in MCF-7 cells were investigated.

Materials and methods: Growth inhibition induced by emodin was investigated by the MTS assay and the colony formation assay; while emodin-induced apoptosis was determined by the COMET assay and DNA fragmentation detection. Emodin (35?μM)-induced alterations in the expression of apoptotic-related genes were detected by using real-time PCR.

Results: Emodin had significant growth inhibitory effects on MCF-7 cells with IC₅₀?=?7.22?µg/ml (～30?μM). It also exerted a concentration-dependant inhibitory effect on the colony-forming ability of MCF-7 cells with IC₅₀?=?7.60?µg/ml (～30?µM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in emodin-treated MCF-7 cells. The gene expression of Fas ligand (FASL) was up-regulated (p?<?0.01) but those of MCL1, CCND1 and C-MYC were down-regulated (p?<?0.05) in emodin-treated MCF-7 cells.

Discussion and conclusion: This study indicated that emodin could induce growth inhibition and apoptosis in MCF-7 cells through the modulation of the expression of apoptosis-related genes. The growth inhibitory effects of emodin might involve both the intrinsic and the extrinsic apoptotic pathways and cell cycle arrest.     

Autophagic cell death, polyploidy and senescence induced in breast tumor cells by the substituted pyrrole JG-03-14, a novel microtubule poison

JG-03-14, a substituted pyrrole that inhibits microtubule polymerization, was screened against MCF-7 (p53 wild type), MDA-MB231 (p53 mutant), MCF-7/caspase 3 and MCF-7/ADR (multidrug resistant) breast tumor cell lines. Cell viability and growth inhibition were assessed by the crystal violet dye assay. Apoptosis was evaluated by the TUNEL assay, cell cycle distribution by flow cytometry, autophagy by acridine orange staining of vesicle formation, and senescence based on beta-galactosidase staining and cell morphology. Our studies indicate that exposure to JG-03-14, at a concentration of 500 nM, induces time-dependent cell death in the MCF-7 and MDA-MB231 cell lines. In MCF-7 cells, a residual surviving cell population was found to be senescent; in contrast, there was no surviving senescent population in treated MDA-MB231 cells. No proliferative recovery was detected over a period of 15 days post-treatment in either cell line. Both the TUNEL assay and FLOW cytometry indicated a relatively limited degree of apoptosis (<10%) in response to drug treatment in MCF-7 cells with more extensive apoptosis (but <20%) in MDA-MB231 cells; acidic vacuole formation indicative of autophagic cell death was relatively extensive in both MCF-7 and MDA-MB231 cells. In addition, JG-03-14 induced the formation of a large hyperdiploid cell population in MDA-MB231 cells. JG-03-14 also demonstrated pronounced anti-proliferative activity in MCF-7/caspase 3 cells and in the MCF-7/ADR cell line. The observation that JG-03-14 promotes autophagic cell death and also retains activity in tumor cells expressing the multidrug resistance pump indicates that novel microtubule poisons of the substituted pyrroles class may hold promise in the treatment of breast cancer.     

Annosquacin B induces mitochondrial apoptosis in multidrug resistant human breast cancer cell line MCF-7/ADR through selectively modulating MAPKs pathways

Context: Multidrug resistance (MDR) is a major obstacle to efficient therapy of cancers. It is a prime concern for researchers to find compounds with anti-proliferative activity on MDR cell lines. In recent years, annonaceous acetogenins (ACGs) were reported to have anti-proliferative activity. However, the underlying mechanisms are still unknown.

Objective: This study determines the mechanisms of anti-proliferative activity induced by Annosquacin B (AB) against MCF-7/ADR cells.

Material and methods: The cytotoxicity of AB at varying concentrations (0.64, 1.6, 4, 10, 25, 62.5, 156.25?μM) on MCF-7/ADR cells was assessed using the MTT assay. Annexin V-FITC/propidium iodide staining and Acrinidine orange and ethidium bromide (AO/EB) staining were employed to investigate whether AB (14, 7, 3.5?μM) could induce apoptosis in MCF-7/ADR cells. Levels of caspase-3 and caspase-9, Bax, Bcl-2 and MAPKs kinases were evaluated by western blot assay following treatment with various concentrations of AB (3.5, 7, 14?μM) at different time points (0, 0.5, 1, 2, 4, 8, 12?h).

Results and conclusion: MTT assay showed that AB significantly decreased cell viability on MCF-7/ADR (IC₅₀ of 14.69?μM). AB-induced apoptosis in MCF-7/ADR cells through mitochondrial apoptosis pathways. It induced typical apoptosis by morphologic changes; elevate levels of caspase-3, caspase-9 as well as the ratio of Bax/Bcl-2. In addition, AB increased the expression of p-p38 MAPK and decreased the expression of p-JNK, while whether ERK1/2 had an effect on the MCF-7/ADR apoptosis remains to be determined.     

Triphenylphosphonium-modified mitochondria-targeted paclitaxel nanocrystals for overcoming multidrug resistance

Mitochondria are currently known as novel targets for treating cancer, especially for tumors displaying multidrug resistance (MDR). This present study aimed to develop a mitochondria-targeted delivery system by using triphenylphosphonium cation (TPP⁺)-conjugated Brij 98 as the functional stabilizer to modify paclitaxel (PTX) nanocrystals (NCs) against drug-resistant cancer cells. Evaluations were performed on 2D monolayer and 3D multicellular spheroids (MCs) of MCF-7 cells and MCF-7/ADR cells. In comparison with free PTX and the non-targeted PTX NCs, the targeted PTX NCs showed the strongest cytotoxicity against both 2D MCF-7 and MCF-7/ADR cells, which was correlated with decreased mitochondrial membrane potential. The targeted PTX NCs exhibited deeper penetration on MCF-7 MCs and more significant growth inhibition on both MCF-7 and MCF-7/ADR MCs. The proposed strategy indicated that the TPP⁺-modified NCs represent a potentially viable approach for targeted chemotherapeutic molecules to mitochondria. This strategy might provide promising therapeutic outcomes to overcome MDR.     

Curcumin-docetaxel co-loaded nanosuspension for enhanced anti-breast cancer activity

ABSTRACT

Purpose: A curcumin-docetaxel co-loaded nanosuspension with increased anti-breast cancer activity was developed. Curcumin is a potential anticancer agent with p-glycoprotein (p-gp) inhibiting activity may be co-administered with docetaxel as a nanosuspension to enhance its anticancer effect by increasing the oral bioavailability and decreasing drug efflux.

Methods: Nanosuspensions of curcumin and docetaxel were prepared by precipitation-homozenisation technique and evaluated for particle size, polydispersity, zeta potential and drug release. The in vitro MTT assay was conducted using MCF-7 for anti-breast cancer activity. The in vivo biodistribution by radiolabeling and tumor inhibition study was conducted in mice.

Results: Homogenous nanosuspensions of 80 ± 20 nm were obtained with increased solubility. The drugs as nanosuspensions showed higher cytotoxicity on MCF-7 cell line compared to their suspensions due to the increased in vitro cellular uptake. Due to this increased solubility, sensitization of tumor cells and inhibition of p-gp the in-vivo results showed greater tumor inhibition rate of up to 70% in MCF-7 treated mice. Histopathological results showed higher apoptotic activity and reduced level of angiogenesis.

Conclusions: The in vitro and in vivo study of the nanosuspensions has shown that Co-administration of Curcumin as a p-gp inhibitor with docetaxel may have the potential to increase the anti-breast cancer efficacy of both drugs.     

Effect of organic isothiocyanates on the P-glycoprotein- and MRP1-mediated transport of daunomycin and vinblastine

Purpose. Organic isothiocyanates (ITCs), or mustard oils, are non-nutrient components present in the diet, especially in cruciferous vegetables. The purpose of this investigation was to examine the effect of ITCs on P-glycoprotein (P-gp)- and multidrug resistance-associated Protein (MRP1)-mediated transport in multidrug resistant (MDR) human cancer cell lines. Methods. The direct effect of ITCs on the 2-h cellular accumulation of daunomycin (DNM) and vinblastine (VBL), substrates for both P-gp and MRP1, were measured in sensitive and resistant MCF-7 cells and in PANC-1 cells. Resistant MCF-7 cells (MCF-7/ADR) overexpress P-gp whereas PANC-1 cells overexpress MRP1. The following compounds were evaluated: allyl-, benzyl-(BITC), hexyl-, phenethyl-(PEITC), phenyl-, 1-naphthyl-(NITC), phenylhexyl-, phenylpropyl-, and phenylbutyl-ITC, sulforaphane, erucin, and erysolin. Results. NITC significantly increased the accumulation of DNM and VBL in both resistant cell lines, but had no effect on DNM accumulation in sensitive MCF-7 cells. VBL accumulation in resistant MCF-7 cells was increased 40-fold by NITC whereas that in PANC-1 cells was increased 5.5-fold. Significant effects on the accumulation of DNM and VBL in resistant MCF-7 cells were also observed with benzyl-isothiocyanate whereas PEITC, erysolin, phenylhexyl-ITC, and phenylbutyl-ITC increased the accumulation of DNM and/or VBL in PANC-1 cells. Overall, the inhibitory activities of these compounds in MCF-7 cells and PANC-1 cells were significantly correlated (r²= 0.77 and 0.86 for DNM and VBL, respectively). Significant effects on accumulation were generally observed with the ITCs at 50 M concentrations, but not at 10 M concentrations. Conclusions. One strategy to enhance the effectiveness of cancer chemotherapy is to reverse the MDR phenomena. Our results indicate that certain dietary ITCs inhibit the P-gp- and the MRP1-mediated efflux of DNM and VBL in MDR cancer cells and suggest the potential for diet-drug interactions.     

叶酸受体及二氢叶酸还原酶与人乳腺癌细胞MCF-7/ADR多药耐药的关系

目的以人乳腺癌多药耐药细胞系MCF-7/ADR及其敏感亲本系MCF-7为对象,探讨叶酸受体(FOLRα)及其下游基因二氢叶酸还原酶(DHFR)的表达与乳腺癌细胞多药耐药的关系。方法 MTT法测定阿霉素的细胞毒性作用及DHFR抑制剂对MCF-7/ADR细胞多药耐药的逆转作用;RT-PCR检测细胞FOLRα和DHFR mRNA的表达水平;免疫细胞化学检测FOLRα、P-gp的表达水平。结果 MCF-7细胞增殖速度快于MCF-7/ADR细胞,MCF-7细胞FOLRα mRNA转录水平较MCF-7/ADR细胞高,而MCF-7/ADR细胞DHFR mRNA较MCF-7细胞转录水平高;免疫细胞化学显示MCF-7细胞FOLRα的表达高于MCF-7/ADR细胞,而MCF-7/ADR细胞P-gp的表达较MCF-7细胞高;MCF-7/ADR对甲氨蝶啶无耐药性,甲氨蝶啶对MCF-7/ADR细胞多药耐药有逆转作用。结论 MCF-7/ADR细胞FOLRα的表达水平下调可能与细胞增殖水平有关,其下游基因DHFR表达水平与MCF-7/ADR细胞的MDR可能存在相关性。     

Stabilization of liposomes during drying

Introduction: During the past 40 years, liposomes have been investigated intensively as drug carriers for anticancer drugs and as the adjuvant components of vaccines, for example. In this context, the development of dry formulations of liposomes is important to ensure a more stable drug product and to avoid the use of the ‘cold chain’ during distribution.

Areas covered: This review provides an overview of the technologies commonly used for the drying of liposomal formulations and the significance of formulation and processing parameters for the drying process. In addition, a review is provided of the protective mechanisms proposed to be responsible for stabilization during processing and in the dry state, with special emphasis on the techniques used for the characterization of the mechanisms. Parameters are discussed that critically influence the liposomal stability during drying and the underlying stabilization mechanisms, including the water replacement theory, vitrification and kosmotropic effects.

Expert opinion: Drying of liposomal formulations has contributed to the development of more stable products because liposomes can be dehydrated in the presence of appropriate stabilizing excipients, without affecting the size or the drug encapsulation efficiency. The key to the successful design and preparation of optimal liposomal dry powder formulations is an understanding of the significance of the drying process parameters, and the mechanisms responsible for the stabilization of liposomes during drying and in the dry state.     

The use of single chain Fv as targeting agents for immunoliposomes: an update on immunoliposomal drugs for cancer treatment

Importance of the field: Targeted liposomal drugs represent the next evolution of liposomal drug delivery in cancer treatment. In various preclinical cancer models, antibody-targeted PEGylated liposomal drugs have demonstrated superior therapeutic effects over their non-targeted counterparts. Single chain Fv (scFv) has gained popularity in recent years as the targeting agent of choice over traditional targeting agents such as monoclonal antibodies (mAb) and antibody fragments (e.g., Fab′).

Areas covered in this review: This review is focused mainly on advances in scFv-targeted liposomal drug delivery for the treatment of cancers, based on a survey of the recent literature, and on experiments done in a murine model of human B-lymphoma, using anti-CD19 targeted liposomes targeted with whole mAb, Fab′ fragments and scFv fragments.

What the reader will gain: This review examines the recent advances in PEGylated immunoliposomal drug delivery, focusing on scFv fragments as targeting agents, in comparison with Fab′ and mAb.

Take home message: For clinical development, scFv are potentially preferred targeting agents for PEGylated liposomes over mAb and Fab′, owing to factors such as decreased immunogenicity, and pharmacokinetics/biodistribution profiles that are similar to non-targeted PEGylated (Stealth^®) liposomes.     

Development of novel application of 3,3′-diindolylmethane: sensitizing multidrug resistance human breast cancer cells to γ-irradiation

Context: Multidrug resistance (MDR) is known as a major obstacle to effective cancer therapy. The effects of irradiation on MDR in cancer cells had rarely been reported.

Objective: The effect of 3,3′-diindolylmethane (DIM) sensitizing MDR human breast carcinoma to γ-irradiation was investigated.

Materials and methods: MCF-7/ADR cells were exposed to different concentrations of DIM (0–30?μM) for 48 or 2?h before IR (γ-Co⁶⁰, 10?Gy, room temperature) then cultured for 48?h. Cell survival was determined by MTT assay. Intracellular reactive oxygen spices (ROS) induced by DIM (20 and 30?μM, 2?h before irradiation) was measured by flow cytometry. Propidium iodide staining assay was used for cell cycle distribution studies; cell apoptosis was measured by flow cytometry and confocal microscopy.

Results: DIM (20 and 30?μM, 2?h before irradiation) sensitized MCF-7/ADR cells to IR with survival rates decreased from 100% to 79% and 63%, respectively. DIM combined with γ-radiation demonstrated that the activity of G2/M phase cell cycle arresting with percentages enhanced from 9% to 49% and 52%. DIM can increase intracellular ROS generation by 1.45- and 1.55-times compared to control group. Significantly enhanced radiation-induced apoptosis by DIM was also observed.

Discussion and conclusion: These data provide a rationale for the use of DIM as a promising radio-sensitizer to MDR cancer cells.