The Effect of Hyperthermia on Doxorubicin Therapy and Nanoparticle Penetration in Multicellular Ovarian Cancer Spheroids

The efficient treatment of cancer with chemotherapy is challenged by the limited penetration of drugs into the tumor. Nanoparticles (10 – 100 nanometers) have emerged as a logical choice to specifically deliver chemotherapeutics to tumors, however, their transport into the tumor is also impeded owing to their bigger size compared to free drug moieties. Currently, monolayer cell cultures, as models for drug testing, cannot recapitulate the structural and functional complexity of in-vivo tumors. Furthermore, strategies to improve drug distribution in tumor tissues are also required. In this study, we hypothesized that hyperthermia (43°C) will improve the distribution of silica nanoparticles in three-dimensional multicellular tumor spheroids. Tumor spheroids mimic the functional and histomorphological complexity of in-vivo avascular tumors and are therefore valuable tools to study drug distribution. Ovarian cancer (Skov3) and uterine sarcoma (MES-SA/Dx5) spheroids were generated using the liquid overlay method. The growth ratio and cytotoxicity assays showed that the application of adjuvant hyperthermia with Doxorubicin (DOX) did not yield higher cell killing compared to DOX therapy alone. These results illustrated the role of spheroids in resistance to heat and DOX. In order to study the cellular uptake kinetics of nanoparticles under hyperthermia conditions, the experimental measurements of silica nanoparticle uptake by cells were fitted using a novel inverse estimation method based on Bayesian estimation. This was coupled with advection reaction transport to model nanoparticle transport in spheroids. The model predicted an increase in Area Under the Curve (AUC) and penetration distance (W1/2) that were validated with in-vitro experiments in spheroids. Based on these observations, a novel multifunctional theranostic nanoparticle probe was created for generating highly localized hyperthermia by encapsulating a Near Infrared (NIR) dye, IR820 (for imaging and hyperthermia) and DOX in Organically modified silica nanoparticles (Ormosil). Pegylated Ormosil nanoparticles had an average diameter of 58.2±3.1 nm, zeta potential of -6.9 ± 0.1 mV and high colloidal stability in physiological buffers. Exposure of the IR820 within the nanoparticles to NIR laser led to the generation of hyperthermia as well as release of DOX which translated to higher cell killing in Skov3 cells, deeper penetration of DOX into spheroids and complete destruction of the spheroids. In-vivo bio-distribution studies showed higher fluorescence from organs and increased plasma elimination life of IR820 compared to free IR820. However, possible aggregation of particles on laser exposure and accumulation in lungs still remain a concern

Physics considerations in targeted anticancer drug delivery by magnetoelectric nanoparticles

In regard to cancer therapy, magnetoelectric nanoparticles (MENs) have proven to be in a class of its own when compared to any other nanoparticle type. Like conventional magnetic nanoparticles, they can be used for externally controlled drug delivery via application of a magnetic field gradient and image-guided delivery. However, unlike conventional nanoparticles, due to the presence of a non-zero magnetoelectric effect, MENs provide a unique mix of important properties to address key challenges in modern cancer therapy: (i) a targeting mechanism driven by a physical force rather than antibody matching, (ii) a high-specificity delivery to enhance the cellular uptake of therapeutic drugs across the cancer cell membranes only, while sparing normal cells, (iii) an externally controlled mechanism to release drugs on demand, and (iv) a capability for image guided precision medicine. These properties separate MEN-based targeted delivery from traditional biotechnology approaches and lay a foundation for the complementary approach of technobiology. The biotechnology approach stems from the underlying biology and exploits bioinformatics to find the right therapy. In contrast, the technobiology approach is geared towards using the physics of molecular-level interactions between cells and nanoparticles to treat cancer at the most fundamental level and thus can be extended to all the cancers. This paper gives an overview of the current state of the art and presents an ab initio model to describe the underlying mechanisms of cancer treatment with MENs from the perspective of basic physics

Development of a PLGA Nanoparticle Drug Delivery System Containing Imaging/Hyperthermia and Chemotherapy Agents

Nanoparticulate drug delivery systems have the potential to allow delivery of diagnostic and therapeutic agents to tumor sites in a targeted manner. The objective of this study was to develop biodegradable poly (DL-lactide-co-glycolic acid) (PLGA) nanoparticles loaded with an imaging/hyperthermia agent and a chemotherapy agent to allow for simultaneous diagnostics and treatment. Indocyanine Green (ICG) was selected as the imaging/hyperthermia agent, and doxorubicin (DOX) as the chemotherapy agent. The modified oil in water emulsion solvent evaporation method was used for PLGA nanoparticle preparation. To achieve an optimal degree of incorporation and particle size, we systematically assessed four independent processing variables including amount of PLGA, initial ICG amount, initial DOX amount, and PVA concentration. For every combination, we measured the nanoparticle size and the percent entrapment of ICG and DOX into the PLGA nanoparticles. The nanoparticles produced by optimal formulation had sizes of 171± 2 nm, (n=3) with a low polydispersity index (0.040 ± 0.014, n=3). We determined the entrapment efficiency (by fluorescence measurements using DMSO burst release) as 44.4 ± 1.6 % for ICG and 74.3 ± 1.9 % for DOX. Drug loading was 0.015 ± 0.001 % w/w for ICG and 0.022 ± 0.001% w/w for DOX (n=3). The release pattern was biphasic

Preparation and Characterization of a Polymeric (PLGA) Nanoparticulate Drug Delivery System With Simultaneous Incorporation of Chemotherapeutic and Thermo-Optical Agents.

The objective of this study was to develop biodegradable poly (DL-lactide-co-glycolic acid) (PLGA) nanoparticles simultaneously loaded with indocyanine green (ICG) and doxorubicin (DOX). The modified oil in water single emulsion solvent evaporation method was used. To enhance the incorporation of both agents and control particle size, four independent processing parameters including amount of polymer, initial ICG content, initial DOX content, and concentration of poly-vinyl alcohol (PVA) were investigated. The ICG and DOX entrapment in nanoparticles as well as the nanoparticle size were determined. The nanoparticles produced by standardized formulation were in the range of 171+/-2 nm (n=3) with low polydispersity index (0.040+/-0.014, n=3). The entrapment efficiency was determined by spectrofluorometer measurements. The efficiency was 44.4+/-1.6% for ICG and 74.3+/-1.9% for DOX. Drug loading was 0.015+/-0.001%, w/w, for ICG and 0.022+/-0.001%, w/w, for DOX (n=3). The release pattern was biphasic. ICG and DOX loaded-nanoparticle preparation was standardized based on the following parameters: PLGA concentration, PVA concentration and initial drug content

Targeted Nanoparticles for Simultaneous Delivery of Chemotherapeutic and Hyperthermia Agents--An in Vitro Study.

The purpose of this study was to prepare targeted Poly lactide-co-glycolide (PLGA) nanoparticles with simultaneous entrapment of indocyanine green (ICG) and doxorubicin (DOX) by surface decorating them with tumor specific monoclonal antibodies in order to achieve simultaneous therapy and imaging. ICG was chosen as an imaging and hyperthermia agent and DOX was used as a chemotherapeutic agent. ICG and DOX were incorporated into PLGA nanoparticles using the oil-in-water emulsion solvent evaporation technique. These nanoparticles were further surface decorated with antibodies against Human Epithelial Receptor-2 (HER-2) using carbodiimide chemistry. The uptake of antibody conjugated ICG-DOX-PLGA nanoparticles (AIDNP) was enhanced in SKOV-3 (HER-2 overexpressing cell lines) compared to their non-conjugated counterparts (ICG-DOX-PLGA nanoparticles (IDNP)). The uptake of antibody conjugated ICG-DOX-PLGA nanoparticles, however, was similar in MES-SA and MES-SA/Dx5 cancer cells (HER-2 negative cell lines), which were used as negative controls. The cytotoxicity results after laser treatment (808 nm, 6.7 W/ cm (2)) showed an enhanced toxicity in treatment of SKOV-3. The negative controls exhibited comparable cytotoxicity with or without exposure to the laser. Thus, this study showed that these antibody conjugated ICG-DOX-PLGA nanoparticles have potential for combinatorial chemotherapy and hyperthermia

Simultaneous Delivery of Chemotherapeutic and Thermal-Optical Agents to Cancer Cells by a Polymeric (PLGA) Nanocarrier: An in Vitro Study.

PURPOSE: To test the effectiveness of a dual-agent-loaded PLGA nanoparticulate drug delivery system containing doxorubicin (DOX) and indocyanine green (ICG) in a DOX-sensitive cell line and two resistant cell lines that have different resistance mechanisms. METHODS: The DOX-sensitive MES-SA uterine sarcoma cell line was used as a negative control. The two resistant cell lines were uterine sarcoma MES-SA/Dx5, which overexpresses the multidrug resistance exporter P-glycoprotein, and ovarian carcinoma SKOV-3, which is less sensitive to doxorubicin due to a p53 gene mutation. The cellular uptake, subcellular localization and cytotoxicity of the two agents when delivered via nanoparticles (NPs) were compared to their free-form administration. RESULTS: The cellular uptake and cytotoxicity of DOX delivered by NPs were comparable to the free form in MES-SA and SKOV-3, but much higher in MES-SA/Dx5, indicating the capability of the NPs to overcome P-glycoprotein resistance mechanisms. NP-encapsulated ICG showed slightly different subcellular localization, but similar fluorescence intensity when compared to free ICG, and retained the ability to generate heat for hyperthermia delivery. CONCLUSION: The dual-agent-loaded system allowed for the simultaneous delivery of hyperthermia and chemotherapy, and this combinational treatment greatly improved cytotoxicity in MES-SA/Dx5 cells and to a lesser extent in SKOV-3 cells

Comparing Cellular Uptake and Cytotoxicity of Targeted Drug Carriers in Cancer Cell Lines With Different Drug Resistance Mechanisms.

The purpose of this study was to compare the cellular uptake and cytotoxicity of targeted and nontargeted doxorubicin (DOX)-loaded poly (d,l-lactide co-glycolide) (PLGA) nanoparticle (NP) drug delivery systems in drug-resistant ovarian (SKOV-3) and uterine (MES-SA/Dx5) cancer cell lines. The cellular uptakes of DOX from nonconjugated DOX-loaded NPs (DNPs) and from HER-2 antibody-conjugated DOX-loaded NPs (ADNPs) in MES-SA/Dx5 cancer cells were higher compared to free DOX. Results also showed higher uptake of DOX from ADNPs in SKOV-3 cells compared with both free DOX and DNPs treatment. Cytotoxicity results at 10 μM extracellular DOX concentration were consistent with the cellular uptake results. Our study concludes that cellular uptake and cytotoxicity of DOX can be improved in MES-SA/Dx5 cells by loading DOX into PLGA NPs. DNPs targeted to membrane receptors may enhance cellular uptake and cytotoxicity in SKOV-3 cells. FROM THE CLINICAL EDITOR: The authors of this study compare the cellular uptake and cytotoxicity of targeted and nontargeted doxorubicin loaded PLGA nanoparticle delivery systems in drug-resistant ovarian and uterine cancer cell lines, concluding that cellular uptake and cytotoxicity of doxorubicin can be improved by the proposed methods

Biodistribution and clearance of magnetoelectric nanoparticles for nanomedical applications using energy dispersive spectroscopy

Aim: The biodistribution and clearance of magnetoelectric nanoparticles (MENs) in a mouse model was studied through electron energy dispersive spectroscopy. Materials &amp; methods: This approach allows for detection of nanoparticles (NPs) in tissues with the spatial resolution of scanning electron microscopy, does not require any tissue-sensitive staining and is not limited to MENs. Results: The size-dependent biodistribution of intravenously administrated MENs was measured in vital organs such as the kidneys, liver, spleen, lungs and brain at four different postinjection times including 1 day, 1 week, 4 and 8 weeks, respectively. Conclusion: The smallest NPs, 10-nm MENs, were cleared relatively rapidly and uniformly across the organs, while the clearance of the larger NPs, 100- and 600-nm MENs, was highly nonlinear with time and nonuniform across the organs. </jats:p