Antitumor Effect of Paclitaxel-Loaded PEGylated Immunoliposomes Against Human Breast Cancer Cells

Purpose The antitumor effect of paclitaxel-loaded PEGylated immunoliposome (PILs) was investigated in breast cancer cell lines and the xenograft model. Methods Herceptin was conjugated to paclitaxel-loaded PEGylated liposomes (PLs). In vitro cellular uptake and cytotoxicity of PILs were determined in breast cancer cell lines while in vivo antitumor efficacy was evaluated in the xenograft nude mouse model. Results The PILs formulation was able to significantly increase the HER2 mediated cellular uptake of paclitaxel compared to the PLs in cell lines overexpressing HER2 (BT-474 and SK-BR-3 cells). However, in the MDA-MB-231 cells, which express low levels of HER2, the difference between the PILs and PLs formulation was not significant. The biological activity of Herceptin was maintained throughout the conjugation process as exhibited by the antitumor dose–response curves determined for Herceptin itself, for the thiolated Herceptin alone and subsequently for the immunoliposome-coupled Herceptin. In BT-474 and SK-BR-3 cells, the cytotoxicity of the PILs was more potent than that of Taxol. Moreover, in in vivo studies, PILs showed significantly higher tumor tissue distribution of paclitaxel in the BT-474 xenograft model and more superior antitumor efficacy compared to Taxol and PLs. However, in the MDA-MB-231 xenograft model, PILs and PLs showed similar tumor tissue distribution as well as antitumor activity. Conclusions These results suggest that HER2-mediated endocytosis is involved in the PILs formulation. The ability of the PILs formulation to efficiently and specifically deliver paclitaxel to the HER2-overexpressing cancer cells implies that it is a promising strategy for tumor-specific therapy for HER2-overexpressing breast cancers.     

Trastuzumab-conjugated vitamin E TPGS liposomes for sustained and targeted delivery of docetaxel

Objectives: In this study, the authors developed d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS or simply TPGS) liposomes and further conjugated them to trastuzumab for controlled and targeted delivery of docetaxel (DTX) as a model hydrophobic drug.

Methods: DTX- or coumarin-6-loaded liposomes were prepared by solvent injection method and characterized for size and size distribution, surface charge, surface chemistry and drug encapsulation efficiency and drug release profile. SK-BR-3 cells were employed as an in vitro model for HER2-positive breast cancer and assessed for their cellular uptake and cytotoxicity of the two liposomal formulations. In vivo pharmacokinetics (PK) was investigated in Sprague–Dawley rats.

Results: The IC₅₀ value was found to be 20.23 ± 1.95, 3.74 ± 0.98, 0.08 ± 0.4 μg/ml for the marketed preparation of DTX, TPGS liposomes and trastuzumab-conjugated TPGS liposomes, respectively after 24 h incubation with SK-BR-3 cells. In vivo PK experiments showed that i.v. administration of trastuzumab-conjugated liposomes achieved 1.9 and 10 times longer half-life, respectively than PEG-coated liposomes and DTX. The area under the curve (AUC) was increased by 3.47- and 1.728-fold, respectively.

Conclusion: The trastuzumab-conjugated vitamin E TPGS-coated liposomes showed greater potential for sustained and targeted chemotherapy in the treatment of HER2 overexpressing breast cancer.     

Pro-inflammatory cytokine inhibition in the primate using microencapsulated antisense oligomers to NF-κB

Primary objective: Antisense oligomers to NF-κB (ASO) were incorporated into albumin microspheres to determine if microcapsules containing ASO inhibit pro-inflammatory cytokines to a greater extent than comparable doses of ASO in solution. Phagocytosis of microcapsules and intracellular release of ASO in macrophages was evaluated.

Research design: Comparable doses of microencapsulated ASO and ASO in solution were evaluated in non-human primates.

Methods: Blood was sampled and stimulated with Escherichia coli endotoxin ex vivo. TNF, IL-1 and IL-6 concentrations were compared for 72?hrs. The intracellular concentration of ASO was measured in macrophages in vitro to evaluate the difference in intracellular penetration of microencapsulated ASO.

Results: Microencapsulated ASO produced significantly greater cytokine inhibition at all time points compared to ASO in solution. There were no side effects to ASO in the baboons. Intracellular ASO concentration was 10 fold greater in macrophages using microencapsulation.

Conclusions: Microencapsulated ASO to NF-κB is more effective than ASO in solution in pro-inflammatory cytokine inhibition in non-human primates.     

Topical hyaluronan alone promotes corneal epithelial cell migration whereas combination with benzalkonium chloride impairs epithelial wound healing

Abstract

Purpose: To evaluate the effects of topical hyaluronan (HA) on corneal epithelial wound healing when administered with or without benzalkonium chloride (BAC).

Methods: A cultured human corneal epithelial cell line (HCE-T) was subjected to in vitro scratch assays and in situ epithelial migration was evaluated in organ-cultured rabbit corneas. The corneal epithelium of C57BL/6J mice was also evaluated to determine in vivo wound healing. An in vivo imaging system was also used to evaluate the effects of HA on eye drop retention on the ocular surface.

Results: The findings revealed the promotion of HCE-T migration, in situ rabbit corneal epithelial migration, and in vivo wound healing in mouse corneal epithelium by HA. Pre-treatment with HA also protected against delayed epithelial wound healing in BAC in vitro. However, pre-treatment with 3?mg/mL HA did not show a protective effect against BAC in vivo, but instead delayed epithelial wound healing and increased detection of cleaved caspase-3. This suggested that HA promotes the retention of BAC on the ocular surface. The instilled HA was retained after 15?min, at a significantly higher rate than for phosphate-buffered saline.

Conclusions: The combination of HA and BAC impaired wound healing in the corneal epithelium.     

Ardisiphenol D,a resorcinol derivative identified from Ardisia brevicaulis,exerts antitumor effect through inducing apoptosis in human non-small-cell lung cancer A549 cells

Context: The in vitro and in vivo antitumor activities of ardisiphenol D, a natural product isolated from the roots of Ardisa brevicaulis Diels (Myrsinaceae), have been studied.

Objective: Previously, we have isolated and identified some chemical constituents from this plant. Furthermore, these compounds showed significant inhibition of the proliferation of human pancreatic PANC-1, human lung A549, human gastrointestinal carcinoma SGC 7901, human breast MCF-7, and human prostate PC-3 cancer cells. In the present paper, a major resorcinol derivative called ardisiphenol D was further studied for its antitumor mechanism.

Materials and methods: MTT assay was used to detect the proliferation of A549 cancer cells. Apoptosis induced by ardisiphenol D was observed by Hoechst 33258 fluorescence staining. Caspase-3 enzyme activity was measured by a commercial caspase-3 enzyme activity detection kit. Protein expression of bax, bcl-2, and caspase-3 was tested by Western blots. In vivo antitumor activity of ardisiphenol D was evaluated by determination of A549 tumor growth in nude mice.

Results: Ardisiphenol D significantly inhibited the proliferation of A549 cells with an IC₅₀ of 0.997?μM with a 48?h treatment. Hoechst 33258 fluorescence staining results indicated the apoptosis of A549 cells induced by 3.125?μM of ardisiphenol D. About 0.39 and 0.78?μM of ardisiphenol D also potently increased the caspase-3 enzyme activity in 24?h. Furthermore, 0.39–3.125?μM of ardisiphenol D induced the activation of caspase-3 protein and the up-regulation of the ratio of bax/bcl-2 protein expression in A549 cells. After i.p. injection, ardisiphenol D (5?mg/kg) also strongly suppressed the A549 tumor growth in nude mice.

Discussion and conclusion: Ardisiphenol D induced apoptosis of A549 cells via activation of caspase-3 and up-regulation of the ratio of bax/bcl-2 protein expression. Ardisiphenol D also strongly suppressed the A549 tumor growth in nude mice and exerted antitumor activity in vivo.     

表没食子儿茶素没食子酸酯联合曲妥珠单抗对HER2过表达乳腺癌细胞增殖的影响及其机制

目的 研究表没食子儿茶素没食子酸酯（EGCG）联合曲妥珠单抗对人表皮生长因子受体2(HER2)过表达乳腺癌细胞增殖的影响及其作用机制。方法 表达纯化曲妥珠单抗;用CCK-8细胞增殖检测试剂盒（CCK8）检测不同浓度EGCG、曲妥珠单抗及两药联用对HER2过表达乳腺癌细胞BT474、SK-BR-3的增殖抑制作用;用Western blot法检测EGCG、曲妥珠单抗及两药联用对BT474乳腺癌细胞中HER2,表皮生长因子受体（EGFR）,丝裂原激活的蛋白激酶（MAPK）和蛋白激酶B(Akt)及它们的磷酸化蛋白的表达水平的影响。结果 细胞增殖试验结果显示,EGCG、曲妥珠单抗以及二者联用均能有效抑制BT474和SK-BR-3细胞的增殖,且在一定浓度范围内,EGCG与曲妥珠单抗联用显示出协同增殖抑制作用。Western blot结果显示EGCG、曲妥珠单抗以及二者联合均能抑制BT474细胞中Akt,MAPK,EGFR,HER2的磷酸化蛋白表达,与单药相比,二者联合抑制作用显著增强,其差异具有统计学意义(P<0.05)。结论 EGCG联合曲妥珠单抗能协同抑制HER2过表达乳腺癌细胞的增殖,...     

In vitro and in vivo antitumor activity of a methanol extract of Dregea volubilis leaves with its antioxidant effect

Context: In India, Dregea volubilis (L.f.) Benth. ex Hook.f. (Asclepediaceae), a large twining shrub with a woody vine, is used to treat tumors traditionally.

Objective: This study evaluated the in vitro and in vivo antitumor activity of the methanol extract of Dregea volubilis leaves (MEDV) and elucidated its possible mechanism of action.

Materials and methods: In vitro antitumor activity of MEDV was evaluated against Ehrlich ascites carcinoma (EAC) cell-line. In vivo antitumor and antioxidant activity of MEDV at three dose levels (50, 100, and 200?mg/kg) were determined against EAC tumor-bearing mice. After 24?h of EAC inoculation, the extract was administered for 9 consecutive days. After the administration of the last dose on the 9th day followed by 18?h fasting, mice from all groups were sacrificed to determine antitumor activity and hematological profiles along with liver related biochemical parameters like lipid peroxidation, antioxidant enzymatic activity, etc.

Results: For in vitro antitumor activity, IC₅₀ value of MEDV for EAC tumor cells was 85.51?±?4.07 µg/ml. The MEDV showed a decrease in tumor volume, packed cell volume and viable cell count and an increase in the non-viable cell count of the EAC tumor-bearing mice (p?<?0.001). Hematological profile reverted near to normal level in extract treated mice. MEDV decreased the hepatic lipid peroxidation level and enhanced superoxide dismutase and catalase level in tumor-bearing mice (p?<?0.001).

Discussion and conclusion: MEDV exhibited in vitro and in vivo antitumor activity in EAC tumor-bearing mice mediated through augmenting antioxidant defense system.     

Co-delivery of etoposide and curcumin by lipid nanoparticulate drug delivery system for the treatment of gastric tumors

Context: Gastric carcinoma (GC) is one of the most common cancers and the second most frequent cause of cancer-related deaths. Chemotherapy is an important therapeutic modality for GC. However, chemoresistance limited its success rate. Combination chemotherapy is often applied to prevent drug-induced resistance in cancers.

Objective: The aim of this study is to evaluate whether the co-delivery of etoposide (ETP) and curcumin (CUR) with one nanoparticle can result in synergistic effects of both drugs.

Methods: ETP- and CUR-loaded nanostructured lipid carriers (ETP-CUR-NLC) were prepared by the solvent injection technique. Their average size, zeta potential and drug loading were evaluated. Human gastric cancer cell lines (SGC7901 cells) were used for the testing of in vitro cytotoxicity studies, and in vivo anti-tumor efficacies of the carriers were evaluated on mice bearing SGC7901 cells xenografts.

Results: ETP-CUR-NLC has a particle size of 114?nm, EPT-loading quantity of 83% and CUR-loading quantity of 82%. ETP-CUR-NLC displayed high cytotoxicity and enhanced antitumor activity in vitro and in vivo. Meanwhile, ETP-CUR-NLC displayed low cytotoxicity in normal tissues in vivo.

Discussion and conclusion: The results demonstrate that ETP-CUR-NLC can achieve impressive anti-tumor activity. By combining CUR, an effective NF-κB inhibitor, with ETP, a powerful anticancer drug, in NLC, we could improve the therapeutic efficacy in cancer treatments. Our results showed that such co-loaded delivery systems could serve as a promising therapeutic approach to improve clinical outcomes against various malignancies.     

Targeted delivery of etoposide to cancer cells by folate-modified nanostructured lipid drug delivery system

Abstract

Context: Cardiotoxicity and myelosuppression of etoposide (ETP) limited its clinical application. Targeted drug delivery system could deliver anticancer agents to the target cancerous cells, thus reducing their toxicity.

Objective: In this study, folate (FA) was applied for the construction of nanostructured lipid carriers (NLCs), and used for targeted delivery of ETP to tumors overexpresses the FA receptors.

Methods: FA-poly (ethylene glycol)-distearoylphosphatidylethanolamine was synthesized. FA decorated and ETP-loaded NLCs (FA-ETP-NLCs) were prepared and the formulation was optimized by Box–Behnken design. Their particle size (PS), zeta potential and drug encapsulation efficiency (EE) was evaluated. In vitro cytotoxicity studies of FA-ETP-NLCs were tested in CT26, SGC7901, NCI-H209 cell lines. In vivo antitumor efficacies of the carriers were evaluated on mice bearing CT26 cells xenografts.

Results: The optimum FA-ETP-NLCs formulations had a PS of 120.86?nm. The growth of CT26, SGC790 or NCI-H209 cells in vitro was obviously inhibited. FA-ETP-NLCs also displayed the best antitumor activity than other formulations in vivo.

Conclusion: The results demonstrated that FA-ETP-NLCs were efficient in selective delivery to CT26, SGC790 or NCI-H209 cells overexpressing the FA receptors. Also, FA-ETP-NLCs can sufficiently transfer ETP to the cancer cells, enhance the antitumor capacity. Thus, FA-ETP-NLCs could prove to be a superior nanomedicine to achieve tumor therapeutic efficacy.     

Stimulation of tumor growthin vitro andin vivo by suramin on the VX2 model

Suramin is an antitrypanosomal compound with confirmed efficacy against several human malignancies. It is generally assumed that its mechanism of action includes the interaction with different growth factors, unlike most of the anticancer drugs. Its anticancer activity has not been testedin vivo against squamous cell carcinoma. The purpose of this study was to assess the efficacy and toxicity of suraminin vivo andin vitro on the VX2 tumor model at therapeutic monitored plasma concentrations. We determined the pharmacokinetics of suramin in rabbits, and modelized its administration in order to obtain plasma concentrations between 150 and 300 μg/ml throughout the treatment course of 3 weeks. Under these conditions, antitumor effects of suramin were evaluatedin vivo by comparing liver tumor involvement in suramin-treated and control rabbits. Liver involvement was quantified by image analysis andin vitro effects were also determined at the same concentrations.In vivo, suramin promoted liver tumor growth significantly (p<0.05), compared to untreated controls.In vitro, suramin significantly stimulated tumor cell growth at concentrations above 200 μg/ml (p<0.01). Suramin may have stimulatory effects on tumor growth in squamous cell carcinoma at relevant plasma drug concentrations. Caution should be taken in further trials in patients with squamous cell carcinomas.     

Novel self-assembled micelles based on palmitoyl-trimethyl-chitosan for efficient delivery of harmine to liver cancer

Backgroud: Polymeric micelles is a safe and effective delivery system, which belong to the targeted delivery system (TDS). An anticancer drug, harmine(HM) is a hydrophobic drug with much adverse effects when used for treatment of liver cancer. Chitosan (CS) is a polysaccharide and can be modified to be an amphiphilic polmer which could self-assemble into micelles and be applied for delivery of hydrophobic drugs.

Objectives: To synthesize three kinds of novel biodegradable polymers, designated as palmitoyl-trimethyl-CS (TPCS)1, TPCS2 and Lac-TPCS2, and investigate their efficiency and mechanism of delivery HM to liver tumors in vitro and in viro.

Results: The self-assembled micelles presented satisfactory particle size (～ 200 nm) and drug release characteristics in vitro. It's proved that Lac-TPCS2/HM may enter HepG2 cell through endocytosis. Antitumor experiments in vivo revealed that Lac-TPCS2/HM could significantly inhibit tumor growth and extend the lifetime of mice bearing H22 tumors after intravenous administration. Subsequently in vivo near-infrared fluorescence imaging results demonstrated a satisfactory liver tumor-targeting effect of Lac-TPCS2/HM.

Conclusion: Three novel polymers hold great potential in the development of nanomedicine for treatment of liver tumors, in particular Lac-TPCS2 exhibits the greatest antitumor potential through active target effect.     

Ovarian cancer targeted hyaluronic acid-based nanoparticle system for paclitaxel delivery to overcome drug resistance

Abstract

Objective: Most primary human ovarian tumors and peritoneal implants, as well as tumor vascular endothelial cells, express the CD44 family of cell surface proteoglycans, the natural ligand for which is hyaluronic acid (HA). Paclitaxel (PTX) is an effective chemotherapeutic agent that is widely used for the treatment of several cancers, including ovarian cancer. This study aimed to develop a HA-based PTX-loaded nanoparticle system to improve the ovarian cancer therapeutic effects.

Methods: PTX-loaded cationic nanostructured lipid nanoparticles (PTX-NLCs) were prepared. HA-PE was then coated onto the PTX-NLCs by electrostatic adsorption to form HA-PTX-NLCs. In vitro tumor cell inhibition efficiency was analyzed on SKOV3 human ovarian cancer cells (SKOV3 cells) and PTX-resistant SKOV3 cells (SKOV3/PTX cells). In vivo anticancer ability was evaluated with mice bearing SKOV3 ovarian cancer cells xenografts.

Results: HA-PTX-NLCs had an average diameter of 163?nm, and PTX was incorporated with an efficiency of over 80%. The in vitro viability of SKOV3 cells and SKOV3/PTX cells was obviously inhibited by HA-PTX-NLCs. In the ovarian cancer cells model, significant reduction in tumor growth was observed, whereas the conventional PTX injection group did not achieve significance.

Conclusion: This study demonstrated that significantly improved results were obtained by the newly constructed HA-PTX-NLCs, in terms of in vitro and in vivo therapeutic efficacy. These findings strongly support the superiority of HA based nano-system for the PTX delivery, thus enhance the efficacy of ovarian cancer chemotherapy.     

Tumor-preferential sustained drug release enhances antitumor activity of block copolymer micelles

Abstract

Nanoparticles are widely used as drug carriers for controlled, tumor-targeted delivery of various anticancer agents that have biopharmaceutical limitations such as water solubility and tissue permeability. Growing evidence suggests that nanoparticles not only reduce toxic side effects of anticancer drugs but also improve the therapeutic efficacy as a function of their drug-release profile. The purpose of this study is to confirm such hypothetical effects of tunable drug release on improving antitumor activity of nanoparticles in vitro and in vivo, using block copolymer micelles as drug carriers. Micelles were prepared from poly(ethylene glycol)-poly(aspartate) block copolymers modified with hydrazide (HYD), aminobenzoate hydrazide (ABZ) and glycine hydrazide (GLY) linkers to achieve a pH-dependent, tunable release of doxorubicin (DOX), a model anticancer drug. Regardless of the drug-release profile, all three micelles showed similar properties in vitro, such as pH-dependent drug release, intracellular drug delivery and cancer cell growth inhibition. However, micelles releasing DOX slowly in vitro showed that the most effective antitumor activity in vivo, compared to the micelles releasing drugs faster. These results demonstrate that tumor-preferential sustained drug release can enhance the antitumor activity of the micelles.     

Phospholipids-based microbubbles sonoporation pore size and reseal of cell membrane cultured in vitro

Objective: To investigate phospholipids-based microbubbles induced sonoporation and cell membrane reseal in vitro under various conditions.

Methods: A breast cancer cell line SK-BR-3 was used to investigate ultrasonic sonoporation under various conditions. Atomic force microscopy (AFM) scanning techniques were employed to observe the change of membrane pores.

Results: Normal SK-BR-3 cells membrane pores were evenly distributed and less than 1 μm. After ultrasound exposure, membrane pores were enlarged at different degree depending on ultrasound exposure durations, filling gas species and microbubble suspension concentration. With microbubble suspension concentration being increased to 5% or ultrasound exposure reached 30 s, membrane pores in fluorocarbon (C₃F₈ or SF₆)-filled microbubble groups exceeded 1 μm, which were significantly larger than that of air-filled microbubble group. Membrane pores were about 2–3 μm under ultrasound 60 s with 5% fluorocarbon-filled microbubble suspension. After 24 h of incubation, most of the enlarged membrane pores could reseal to normal size, which corresponded to cell viability.

Conclusions: Membrane pores can be obviously enlarged by ultrasonic sonoporation of fluorocarbon-filled microbubbles, whose reseal time depended on ultrasound exposure duration and microbubble suspension concentration.     

Paridis saponins inhibiting carcinoma growth and metastasis <Emphasis Type="Italic">In vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

Paris polyphylla Smith var. yunnanensis extracts, Rhizoma Paridis saponins (RPS) have been found to show strong antitumor activity. However, few studies have yet investigated pulmonary metastasis treatment with this herb. To detail the effective components in RPS and discuss the preliminary mechanism of antitumor effects in vivo and in vitro, a mixture isolated from RPS was investigated. The main constituents were identified as polyphyllin D, formosanin C, dioscin, Paris H, Paris VII and pennogennin 3-O-α-L-rhamnopyranosyl (1→4)-[β-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside. In our experiments, LA795 cells were exposed to the mixed compounds. Migration inhibition was evaluated by wound healing assay and migration assay in non-cytotoxic dose which was determined by MTT assay. The results demonstrated that the constituent in varying degrees inhibited the migration of the tumor cells in vitro. The mixture also showed antitumor effects on carcinoma in vivo. In conclusion, the mixture is a potent anticancer agent that elicits programmed cell death and inhibits the migration in murine lung adenocarcinoma, both in vitro and in vivo.     

Breast cancer targeted chemotherapy based on doxorubicin-loaded bombesin peptide modified nanocarriers

Context: Breast cancer is the most common cancer in female population. Breast cancer chemotherapy using doxorubicin (DOX) is well illustrated. However, a significant obstacle for successful chemotherapy with DOX is multidrug resistant (MDR) in breast cancer cells. Targeted nanocarriers have emerged as frontier research for the improvement of cancer chemotherapy.

Objective: Bombesin (Bn)-modified, DOX-loaded solid lipid nanoparticles (Bn-DOX/SLNs) were constructed. Doxorubicin-resistant MCF-7/MDR human breast cancer cells and the cancer animal models were applied for the evaluation of the in vitro and in vivo anti-tumor effect of Bn-DOX/SLNs.

Methods: Bn-conjugated lipids were synthesized. DOX was then loaded into Bn-modified SLNs. The physicochemical properties of the Bn-DOX/SLNs were investigated by particle size and zeta potential measurement, drug loading and drug-entrapment efficiency, and in vitro drug release behavior. In vitro cytotoxicity against MCF-7/MDR cells was investigated, and in vivo anti-tumor of SLNs was evaluated in human breast cancer mice models.

Results: Bn-DOX/SLNs showed an excellent in vitro cytotoxicity and in vivo anti-tumor effect both in MCF-7/MDR breast cancer cells and breast cancer animal model.

Conclusion: The results demonstrated that Bn-DOX/SLNs reversed the resistance of doxorubicin, suggesting that chemotherapy using this kind of targeted nanocarriers may benefit human breast MDR cancer therapy.     

New protein kinase inhibitors in breast cancer: afatinib and neratinib

Introduction: Human epidermal growth factor receptor (HER) 2 is overexpressed in 20 – 25% of breast cancers, and has historically been a poor prognostic marker. The introduction of trastuzumab, the first fully humanized monoclonal antibody targeting HER2, has drastically changed the outcomes of metastatic breast cancers. However, despite initial response, most patients develop resistance. Recent data suggest that strategies targeting more than one member of HER family may circumvent trastuzumab resistance and confer synergistic effects.

Areas covered: Following a literature search on PubMed, national meetings and clinicaltrials.gov using ‘afatinib’, ‘neratinib’, ‘HER2’ and ‘breast cancer’ as keywords, we critically analyzed the different HER2-targeted therapies for their drug development and evidence-based therapeutic strategies. Afatinib and neratinib, two second-generation tyrosine kinase inhibitors (TKIs) that irreversibly inhibit more than one HER family member, are being actively investigated in clinical trials either as monotherapy or in combination. We reviewed the efficacy and optimal use of these agents in various settings, such as systemic therapy for advanced breast cancer including brain metastases, and neoadjuvant therapy in early-stage breast cancer.

Expert opinion: HER2-targeted therapies have been widely used and greatly improved the outcome of HER2-positive breast cancer. Despite the accelerated advancement in recent years, several crucial questions remain unanswered, such as how to treat a prior resistance or affect a sanctuary site, that is, CNS metastasis. The novel next-generation TKIs, afatinib and neratinib, were rationally designed to overcome the resistance by targeting multiple HER family members and irreversibly binding the targets. In spite of the encouraging results of the afatinib and neratinib monotherapies, they have not been proven more efficacious in the combination therapies yet, even though multicenter international trials are still ongoing. The key tasks in the future are to study resistance pathways, design novel strategies to more efficiently test combinations for synergistic effects and identify biomarkers and novel imaging tools to guide individualized therapies.     

Formulation of plumbagin loaded long circulating pegylated liposomes: in vivo evaluation in C57BL/6J mice bearing B16F1 melanoma

Context and Objective: Plumbagin (2-methyl, 5-hydroxy, 1, 4-naphthoquinone), an anticancer agent is encapsulated either as conventional or long circulating liposomal formulations to enhance its biological half-life and antitumor efficacy.

Methods: The liposomes were prepared by thin film hydration method and in vitro characterization was carried out to examine the particle size, zeta potential, drug encapsulation efficiency and in vitro release. The optimized formulations were tested for pharmacokinetic and pharmacodynamic efficacy against mice bearing B16F1 melanoma. Also in vivo toxicity studies were carried out.

Results and Discussion: The optimum particle size and entrapment efficiency was observed at drug to lipid molar ratio of 1:20. The in-vitro release of plumbagin from the liposomal formulations in phosphate-buffered saline (pH 7.4) showed biphasic release with an initial burst release followed by sustained release phase. Elimination half life (T_1/2) of pegylated, conventional and free plumbagin was 1305.76?±?278.16, 346.87?±?33.82 and 35.89?±?7.95?min respectively. Further, plumbagin exhibited better antitumor efficacy in vivo when administered as long circulating liposomes with no signs of normal tissue toxicity.

Conclusion: It can be concluded that the pegylated liposomes could provide a promising parenteral platform for plumbagin with enhanced plasma half-life and therapeutic efficacy.