Tumoricidal effects of etoposide incorporated into solid lipid nanoparticles after intraperitoneal administration in Dalton's lymphoma bearing mice

RNA-based modulation of macrophage-mediated efferocytosis potentiates antitumor immunity in colorectal cancer

Tumor-associated macrophages play pivotal roles in tumor progression and metastasis. Macrophage-mediated clearance of apoptotic cells (efferocytosis) supports inflammation resolution, contributing to immune evasion in colorectal cancers. To reverse this immunosuppressive process, we propose a readily translatable RNA therapy to selectively inhibit macrophage-mediated efferocytosis in tumor microenvironment. A clinically approved lipid nanoparticle platform (LNP) is employed to encapsulate siRNA for the phagocytic receptor MerTK (siMerTK), enabling selective MerTK inhibition in the diseased organ. Decreased MerTK expression in tumor-associated macrophages results in apoptotic cell accumulation and immune activation in tumor microenvironment, leading to suppressed tumor growth and better survival in both liver and peritoneal metastasis models of colorectal cancers. siMerTK delivery combined with PD-1 blockade further produces enhanced antimetastatic efficacy with reactivated intratumoral immune milieu. Collectively, LNP-based siMerTK delivery combined with immune checkpoint therapy may present a feasible modality for metastatic colorectal cancer therapy.

Preparation and evaluation of etoposide-loaded lipid-based nanosuspensions for high-dose treatment of lymphoma

Aim: High-dose administration of etoposide (VP16) was limited by its poor aqueous solubility and severe systemic toxicity on lymphoma therapy. Herein, a novel VP16-loaded lipid-based nanosuspensions (VP16-LNS) was developed for improving drug solubility, enhancing antitumor effect and reducing systemic toxicity. Materials & methods: VP16-LNS with soya lecithin and D-α-tocopheryl PEG 1000 succinate (TPGS) as stabilizers were prepared by nanoprecipitation method. Results: VP16-LNS exhibited uniform spherical morphology, small particle size and favorable colloidal stability. The concentration of VP16 in VP16-LNS was high enough (1017.67 μg/ml) for high-dose therapy on lymphoma. Moreover, VP16-LNS displayed long blood circulation time, selective intratumoral accumulation, remarkable antitumor effect and upregulated safety. Conclusion: VP16-LNS would be an efficient nanoformulation for clinical intravenous application against lymphoma.

Curcumin formulated in solid lipid nanoparticles has enhanced efficacy in Hodgkin's lymphoma in mice

Curcumin reduces Hodgkin's lymphoma (HL) cell growth in vitro, but its unfavorable pharmacokinetics highlight the need for novel in vivo delivery systems. Thus, we explored whether formulation of curcumin in solid lipid nanoparticles (SLN-curc) or d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) nanoparticles (TPGS-curc) could enhance its efficacy in mice. Curcumin formulated in SLN and in TPGS resulted in higher curcumin plasma levels in mice. Compared to vehicle-treated controls, SLN-curc and TPGS-curc reduced HL xenograft growth by 50.5% (p < 0.02) and 43.0% (p < 0.04), respectively, while curcumin reduced it by 35.8% (p < 0.05). In addition, SLN-curc reduced the expression of proteins involved in cell proliferation and apoptosis (XIAP and Mcl-1) in HL tumor extracts. In HL cells in culture, curcumin decreased the expression of relevant anti-inflammatory cytokines (IL-6 and TNF-α) in a concentration-dependent manner. Moreover, when given in combination with bleomycin, doxorubicin and vinblastine, curcumin showed an additive growth inhibitory effect. In conclusion, SLNs appear as an appropriate and effective drug delivery system for curcumin. Given the efficacy of SLN-curc and the enhanced growth inhibitory effect when combined with chemotherapeutic drugs, we speculate that curcumin, when appropriately formulated, is a promising adjuvant agent for the treatment of HL and merits further evaluation.

Biophysical, biopharmaceutical and toxicological significance of biomedical nanoparticles

Understanding of interplay between nanoparticles physicochemical and biophysical properties, and their impact on pharmacokinetic biodistribution and toxicological properties help designing of appropriate nanoparticle products for biomedical applications.

Different inhibitory effect and mechanism of hydroxyapatite nanoparticles on normal cells and cancer cells in vitro and in vivo

Hydroxyapatite (HAP), similar to inorganic phase in bones, shows good biocompatibility and bioactivity as bone defect repairing material. Recently, nanoscaled HAP shows the special properties differing from bulk HAP in physics, chemistry and biology. This paper demonstrates that HAP nanoparticle (nHAP) possesses the ability for inhibiting cancer cell growth in vitro and in vivo. In vitro, after treatment with nHAP for 3 days, proliferation of human cancer cells are inhibited by more than 65% and by less than 30% for human normal cells. In vivo, injection of nHAP in transplanted tumor results in significant reduction (about 50%) of tumor size. The anticancer effect of nHAP is mainly attributed to high amount by endocytosis in cancer cells and inhibition on protein synthesis in cells. The abundant nHAP internalized in cancer cells around endoplasmic reticulum may inhibit the protein synthesis by decreasing the binding of mRNA to ribosome due to its high adsorption capacity for ribosome and arrest cell cycle in G0/G1 phase. nHAP shows no ROS-involved cytotoxicity and low cytotoxicity to normal cells. These results strongly suggest that nHAP can inhibit cancer cell proliferation and have a potential application in cancer treatment.

Pharmaceutical and pharmacological approaches for bioavailability enhancement of etoposide

Etoposide, a semi-synthetic derivative of podophyllotoxin, is one of the most active and useful antineoplastic agent used routinely in firstline combination chemotherapy of testicular cancer, small-cell lung cancer and non-Hodgkin's lymphoma. Etoposide displays narrow therapeutic index, erratic pharmacokinetics and dose individualization that needs to be achieved for overcoming inter- and intra-patient variability (25-80 percent), so as to maintain proper drug exposure within a therapeutic range. Etoposide possess high plasma protein binding (97 percent) and is degraded via complex metabolic pathways. The main pharmacokinetic determinants of etoposide are still not completely defined in order to optimize the pharmaco-therapeutic parameters including dose, therapeutic schedule and route of administration. Much research has been done to determine drug-drug and herb-drug interactions for improving the bioavailability of etoposide. The present article gives insight on pharmaceutical and pharmacological attempts made from time to time to overcome the erratic inter- and intra-patient variability for improving the bioavailability of etoposide.

Physicochemical properties of liposomes as potential anticancer drugs carriers. Interaction of etoposide and cytarabine with the membrane: spectroscopic studies

The interactions between etoposide, cytarabine and 1,2-dihexadecanoyl-sn-glycerol-3-phosphocholine bilayers were studied using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). These techniques have proven to be a very powerful tool in studying the structure and dynamics of phospholipid bilayers. In particular, DSC can provide information on the phase transition temperature and cooperativity of the lipid molecules in the absence and presence of the drug. Vibrational spectroscopy is well suited to the study of drug-lipid interactions, since it allows for an investigation of the conformation of phospholipid molecules at different levels in lipid bilayers and follows structural changes that occur during the gel to liquid-crystalline phase transition. NMR supported the determination of the main phase transition temperatures (TC) of 1,2-dihexadecanoyl-sn-glycerol-3-phosphocholine (DPPC). The main phase transition temperature (TC) determined by (1)H NMR is comparable with values obtained by DSC for all studied liposomes. The location of cytarabine and etoposide in liposomes was also determined by NMR. Atomic force microscopy (AFM) images, acquired immediately after sample deposition on a mica surface, revealed the spherical shape of lipid vesicles.

Drug development for intraperitoneal chemotherapy against peritoneal carcinomatosis from gastrointestinal cancer

Intraperitoneal (IP) chemotherapy for peritoneal carcinomatosis (PC) from gastrointestinal cancer has been investigated and applied clinically for several decades. Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy have been considered to be the optimal treatment options for selected patients with colorectal and gastric cancers with PC. Accumulating evidence suggests that the administration of IP paclitaxel for patients with PC from gastric cancer may improve the patient survival. The pharmacokinetics of such treatment should be considered to optimize IP chemotherapy. In addition, newly emerging molecular-targeted therapies and research into new drug delivery systems, such as nanomedicine or controlled absorption/release methods, are essential to improve the effects of IP chemotherapy. This review summarizes the current status and future prospects of IP chemotherapy for the treatment of gastrointestinal cancer.

Rational design for multifunctional non-liposomal lipid-based nanocarriers for cancer management: theory to practice

Nanomedicines have gained more and more attention in cancer therapy thanks to their ability to enhance the tumour accumulation and the intracellular uptake of drugs while reducing their inactivation and toxicity. In parallel, nanocarriers have been successfully employed as diagnostic tools increasing imaging resolution holding great promises both in preclinical research and in clinical settings. Lipid-based nanocarriers are a class of biocompatible and biodegradable vehicles that provide advanced delivery of therapeutic and imaging agents, improving pharmacokinetic profile and safety. One of most promising engineering challenges is the design of innovative and versatile multifunctional targeted nanotechnologies for cancer treatment and diagnosis. This review aims to highlight rational approaches to design multifunctional non liposomal lipid-based nanocarriers providing an update of literature in this field.

Development and in vitro evaluation of a novel lipid nanocapsule formulation of etoposide

Small cell lung cancer (SCLC) is the most aggressive carcinoma in thoracic oncology, unfortunately, despite chemotherapy, relapse is constant. The effect of etoposide, a major drug used against SCLC, can potentially be enhanced after its encapsulation in nanocarriers. The aim of this study was to use the technology of lipid nanocapsules (LNCs) to obtain nanocarriers with drug loadings compatible with clinical use and with an industrial process. Solubility studies with different co-solvent were first performed, then several process were developed to obtain LNCs. LNCs were then characterized (size, zeta potential, and drug loading). The best formulation called Ω-LNCs had a size of 54.1±2.0 nm and a zeta potential of -5.8±3.5 mV and a etoposide drug loading of 5.7±0.3mg/g. The characteristics of this formulation were maintained after freeze drying and after a 15× scale-up. Release studies in a media mimicking plasma composition showed that 40% of the drug was released from the LNCs after 48 h. Moreover the activity of etoposide after encapsulation was enhanced on H209 cells, IC50 was 100 μM and 2.5 μM for etoposide and etoposide LNCs respectively. Unfortunately the formulation failed to be more cytotoxic than etoposide alone on H69AR cells that are resistant to etoposide. This study showed that is was possible to obtain a new etoposide nanocarrier without the use of organic solvent, that the process is suitable for scale-up and freeze drying and finally that etoposide activity is maintained which is very promising for future treatment of SCLC.

Development and evaluation of sustained-release etoposide-loaded poly(ε-caprolactone) implants

Poly(ε-caprolactone) implants containing etoposide, an important chemotherapeutic agent and topoisomerase II inhibitor, were fabricated by a melt method and characterized in terms of content uniformity, morphology, drug physical state, and sterility. In vitro and in vivo drug release from the implants was also evaluated. The cytotoxic activity of implants against HeLa cells was studied. The short-term tolerance of the implants was investigated after subcutaneous implantation in mice. The original chemical structure of etoposide was preserved after incorporation into the polymeric matrix, in which the drug was dispersed uniformly. Etoposide was present in crystalline form in the polymeric implant. In vitro release study showed prolonged and controlled release of etoposide, which showed cytotoxicity activity against HeLa cells. After implantation, good correlation between in vitro and in vivo drug release was found. The implants demonstrated good short-term tolerance in mice. These results tend to show that etoposide-loaded implants could be potentially applied as a local etoposide delivery system.

Phospho-sulindac (OXT-328) inhibits the growth of human lung cancer xenografts in mice: enhanced efficacy and mitochondria targeting by its formulation in solid lipid nanoparticles

PURPOSE

To evaluate the antitumor efficacy of solid lipid nanoparticle-encapsulated phospho-sulindac (SLN-PS) in human lung cancer.

METHODS

PS was incorporated into SLNs using the emulsion evaporation technique. We determined the antitumor activity of SLN-PS in cultured lung cancer cells. The performance of SLN-PS was further evaluated by pharmacokinetic studies in mice and in a model of human lung cancer xenografts in nude mice.

RESULTS

SLN-PS was >4-fold more potent than PS in inhibiting the growth of A549 and H510 cells in vitro. SLN-PS enhanced cellular uptake and facilitated PS accumulation in mitochondria, leading to oxidative stress and apoptosis via the mitochondrial-apoptosis pathway. SLN-PS was highly effective in suppressing the growth of A549 xenografts (78% inhibition compared to control, p < 0.01); while PS had no significant effect. Formulation of PS in SLNs resulted in improved pharmacokinetics in mice and an enhanced (≈ 14-fold) accumulation of PS and its metabolites in A549 xenografts. Finally, SLN-PS enhanced urinary F2-isoprostane uniquely in mice bearing A549 xenografts compared to untreated controls, suggesting that SLN-PS specifically induced oxidative stress in tumors.

CONCLUSIONS

Our results show that SLN-PS is efficacious in suppressing the growth of lung cancer and merits further evaluation.

Antitumor effect and pharmacokinetics of intraperitoneal NK105, a nanomicellar paclitaxel formulation for peritoneal dissemination

The intraperitoneal administration of paclitaxel has been shown to be a promising treatment strategy for peritoneal malignancy. The present study evaluated the effects of intraperitoneal administration of NK105, a paclitaxel-incorporating micellar nanoparticle, which has been shown to have a remarkable effect in a mouse model of gastric cancer. Intraperitoneal NK105 significantly reduced peritoneal tumors in vivo compared with the conventional paclitaxel formulation of paclitaxel solubilized in Cremophor EL and ethanol (PTX-Cre). Moreover, intraperitoneal NK105 significantly reduced the size of subcutaneously inoculated tumors, whereas no such effect was seen with PTX-Cre. Similar systemic toxic effects were observed following the intraperitoneal administration of both NK105 and PTX-Cre. Although NK105 disappeared rapidly almost within a day from the peritoneal cavity, the paclitaxel concentration in peritoneal nodules 4 h after intraperitoneal administration was significantly higher in the NK105 group than in the PTX-Cre group (P < 0.05), whereas there were no significant differences in liver paclitaxel concentrations between the two groups. We also evaluated the pharmacokinetics following intraperitoneal administration of NK105 and PTX-Cre. Serum paclitaxel concentrations 6, 12, 24, and 48 h after the intraperitoneal administration of the drugs were significantly higher in the NK105 than the PTX-Cre group. Furthermore, the peak serum concentration was higher in the NK105 than PTX-Cre group (24 100 ± 3560 vs 108 ± 25 ng/mL, respectively; P < 0.001), as was the area under the concentration-time curve from 0 to 48 h (191 000 ± 32 100 vs 1500 ± 108 ng·h/mL, respectively; P < 0.001). Therefore, intraperitoneal chemotherapy with nanoparticulate paclitaxel NK105 may offer a novel treatment strategy for improving drug delivery in gastric cancer with peritoneal dissemination because of enhanced drug penetration into peritoneal nodules and its prolonged presence in the systemic circulation.

Toxicogenomics of nanoparticulate delivery of etoposide: potential impact on nanotechnology in retinoblastoma therapy

To develop a suitable formulation with high entrapment efficiency, etoposide-loaded poly(lactide-co-glycolide) nanoparticles (NPs) were formulated by single emulsion-solvent evaporation method by changing different formulation parameters such as drug loading, choice of organic solvent and percentage of emulsifier polyvinyl alcohol. The NPs showed higher entrapment efficiency, ~86% (with 15% (w/w) drug loading). The physicochemical parameters revealed smooth topology with size range (240–320 nm), a negative zeta potential (~19 mV) and in vitro sustained-release activity (~60% drug release in 40 days). Greater anti-proliferative activity ~100 times was observed with NPs (IC₅₀ = 0.002 μg/ml) than that of native etoposide (IC₅₀ = 0.2 μg/ml) in retinoblastoma cell line (Y-79). These NPs demonstrated greater (G1/S) blocking and decreased mitochondrial membrane potential as measured by flow cytometry. There was upregulation of apoptotic gene activity in NPs than native etoposide, as revealed through microarray analysis. However, this is the first ever report demonstrating the intricate modulation of genetic network affected by NPs. Collectively, these results suggest that etoposide-loaded NPs could be potentially useful as a novel drug delivery system for retinoblastoma in the future.

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Chapter 6 - Solid lipid nanoparticle formulations pharmacokinetic and biopharmaceutical aspects in drug delivery

Solid lipid nanoparticles (SLNs) have emerged as important tools to modify the release profile for a large number of drugs including protein and peptide molecules. SLNs are produced from biocompatible and biodegradable lipid materials, making them a promising therapeutic strategy for drug targeting and delivery, and surmounting the inherent limitations of regulation acceptance. Due to their versatility in loading both lipophilic and hydrophilic molecules in the solid lipid matrix, SLNs depict the ability to prolong, extend or sustain the release profile of the loaded molecules, therefore reducing the repeated administration, and increasing the therapeutic value of a certain treatment. Additional advantages include reduction of drug toxicity and increase of drug bioavailability. To develop SLN formulations for drug targeting and delivery, a basic pharmacokinetic understanding of drug distribution is of major relevance, as well as the biopharmaceutical aspects of the administration route. This chapter provides a fundamental understanding of the pharmacokinetic properties of SLNs, which influence both biopharmaceutical and clinical profiles of the loaded molecules.