Effective Anticancer Drug Delivery Research Articles

Abstract LB279: The combination therapy with B7-H3 antibody drug conjugates for effective radiation treatment

Abstract Purpose: Antibody-drug conjugate (ADC) is a promising treatment modality because it enables effective tumor-specific delivery of anticancer drugs by targeting cancer antigens with antibodies. By using ADC, each treatment can be used at an optimal dose, thereby minimizing side effects, and maximizing treatment effects. The ADC used in this experiment targets B7-H3, and the B7-H3 protein is highly expressed in various cancer types. Recent studies have shown that B7-H3 is increased by radiation in various cancer cells. This study aims to demonstrate the efficacy of the B7-H3 ADC and confirm its combined effect with radiotherapy. Method: In vitro, colony forming assay, CCK-8 assay, FACs and western blotting were performed in JIMT-1 and HCT116 cell lines. In vivo, JIMT-1, HCT116 and Colon PDX models were developed to monitor tumor growth and survival rate. Biodistribution was performed through the IVIS (In Vivo Imaging System) spectrum. Result: The B7-H3 ADC used in the experiment was developed by combining DUBA as a toxin with anti-B7-H3 antibody In in vitro experiments, the combined treatment of radiation and B7-H3 ADC reduced cell viability via apoptosis more effectively than treatment alone. In the in vivo mouse models, we observed that the combined treatment of radiation and B7-H3 ADC was more effective in inhibiting tumor growth than the single treatment groups. The survival rate of the mice was also improved when the radiation was combined with B7-H3 ADC treatment compared to the other treatment groups alone. In the biodistribution results, the accumulation of B7-H3 ADC-Cy7 was further enhanced when irradiated. Conclusion: The results show that B7-H3 ADC can be used as a promising therapeutic agent and the combined treatment with radiation can obtain an improved anticancer effect than the single treatment, suggesting another cancer treatment method. Citation Format: Gawon Son, Eunjin Ju, Jin Park, Seolhwa Shin, Eunjeong Ko, Miri Kwon, Hyewon Lee, Beomseok Seo, Sangkwang Lee, Seoksoon Park, Seongyun Jeong, Siyeol Song, Eunkyung Choi. The combination therapy with B7-H3 antibody drug conjugates for effective radiation treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB279.

Tunable self-assembly of lipid-based block polymeric micelles with temperature-sensitive poly(vinylcaprolactam) shell for effective anticancer drug delivery

Lipids, as naturally occurring biomolecules have emerged as promising carriers for delivering various therapeutic agents. However, only a few attempts have been made in terms of their applications as amphiphilic block copolymers for anticancer drug delivery. In this work, a biocompatible micellar drug delivery system with fatty acid-based polymer core and temperature-sensitive shell was developed. A series of amphiphilic block copolymers poly(vinyl stearate)/poly(vinyl laurate)-b-poly(N-vinylcaprolactam) (PVS/PVL-b-PNVCL) were synthesized via microwave-assisted reversible addition-fragmentation chain transfer polymerization in a controlled fashion. By varying the fatty acid type and hydrophilic/hydrophobic block lengths, the self-assembly behaviour of the block copolymer micelles proved to be highly tunable in terms of their morphology and particle size. Nile Red and hydrophobic anticancer drug doxorubicin (DOX) were effectively incorporated into the micelles, demonstrating high drug loading capacity, good serum stability, and temperature-dependent drug release characteristics of the polymeric micelles. In vitro studies using cell models revealed that blank PVS -b-PNVCL micelles are biocompatible with different cell lines, while DOX-loaded micelles were internalized into and accumulated in the cells, showing a high cytotoxic effect against HeLa cells. These findings suggest an opportunity for the development of safe and efficient lipid-based micellar system for smart drug delivery and cancer treatments.

Targeted delivery of doxorubicin by SP5-52 peptide conjugated exosome nanoparticles into lung tumor: An in vitro and in vivo study

Here, SP5-52 peptide conjugated exosome nanostructures were developed for targeted delivery of Doxorubicin (DOX) into lung tumor. Exosomes extracted from the serum of Balb/c mice, were characterized in terms of structure and physicochemical properties. Based on the results, the size and zeta potential of exosome NPs were 67 nm and −5 mV, respectively, which was slightly increased after SP5-52 conjugation and DOX loading. The in vitro cell studies displayed that targeted DOX-loaded exosomes had higher cytotoxicity, cellular uptake, and accumulation in LL/2 cell lines compared with non-targeted DOX-loaded exosomes and control groups. Moreover, the therapeutic efficacy of the prepared formulations was evaluated in lung tumor bearing Balb/c mice within 21 days. Accordingly, targeted DOX-loaded exosomes had effectively treated the lung tumor in comparison to other groups. The rate of survival in the mice treated with targeted exosomes was also 35 % higher than other groups; while, the mortality rate was lower. The histopathological evaluation confirmed the accepted off-targeted properties of the targeted exosomes as lower toxicity was observed in different organs rather than lung. This study presents an effective anticancer drug delivery system for specific targeting of induced lung tumor, which could be useful in the treatment of malignant lung cancers in the future.

5-Fluorouracil-loaded designed praseodymium oxide – poly- β-cyclodextrin nanorods for effectively inhibiting breast cancer cells

Breast cancer remains one of the commonly prevailing and challenging diseases. Lanthanide-based nanomaterials are fascinating depending on their unique properties and represent a preferable choice of drug transport, aimed at finding an agent for targeted therapy. It necessitates that lanthanide-based nanocarriers with suitable surface modification and desired physicochemical characteristics are developed for effective anticancer drug delivery, owing to their fascinating light absorption, magnetic, and morphological features. Herein, we report praseodymium oxide nanorods in combination with poly-cyclodextrin as a novel nanocarrier to deliver the chemotherapeutic drug 5-fluorouracil to breast cancer cells. The praseodymium oxide nanoparticles were prepared using a sonochemical method and characterized using routine analytical methods, including X-ray Diffraction, Transmission Electron Microscopy, and X-ray Photoelectron Spectroscopy. The monodisperse rod-shaped structures possess length and width of 200 ± 30 and 72 ± 10 nm, respectively. The nanoparticles are 64.33% crystalline, revealed by XRD. The polymer content in the nanoparticles is ∼37% by weight. Further, the nanoparticles' magnetic, light absorption and photoluminescence characteristics are studied. Low saturation magnetization and insignificant hysteresis properties are observed. Broad absorption and visible wavelength region photoluminescence arise from the praseodymium in the material. The continuous release of the drug cargo and the in vitro anticancer activity are discussed. The loaded drug (5-fluorouracil) is released sustainably, extending over 250 hours. The anticancer activity in vitro is observed with the portion of the drug released from the nanocarrier. The apoptotic action mode of the drug-carrier vehicle is analyzed. The inhibition of cells occurs mainly on the S-phase of the cell cycle. The nanomaterial can function as a drug carrier and is suitable for anticancer therapy. The results reported herein on praseodymium oxide nanoparticles are promising as a nanocarrier and pose the possibility of future in vivo studies.

Synthesis of Zeolitic imidazolate frameworks-8@ layered double hydroxide polyhedral nanocomposite with designed porous voids as an effective carrier for anti-cancer drug-controlled delivery.

In nanotechnology, compounds containing metal materials are used in pharmaceutical sciences. The main purpose of this research was to introduce a novel method to control the amount of zeolite imidazolate framework (ZIF) in water by forming a protective layer such as layered double hydroxide (LDH). Firstly, ZIF was synthesised as the nucleus of the nanocomposite, and then LDH was formed by in situ synthesis as a protective layer. Scanning electron microscope, Fourier-transform infrared spectroscopy, X-Ray Diffraction, and Brunauer, Emmett and Teller techniques were used to determine (ZIF-8@LDH chemical structure and morphology. Our findings revealed that the ZIF-8@LDH-MTX complex could interact with carboxyl groups and trivalent cations by creating a bifurcation bridge, clarity, and high thermal stability. The antibacterial test indicated that ZIF-8@LDH was able to inhibit pathogenic growth. 2,5-Diphenyl-2H-Tetrazolium Bromide assay results showed that ZIF-8@LDH alone had no notable cytotoxic effect on Michigan Cancer Foundation-7 (MCF-7) cancer cells. However, the cytotoxicity rate was significantly increased in treated MCF-7 cells with ZIF-8@LDH-MTX compared to that of treated cells with methotrexate alone, which can be reasoned by the protection of drug structure and increasing its permeability. The drug release profile was constant at pH=7.4. All findings indicated that the ZIF-8@LDH complex could be considered a newly proposed solution for effective anti-cancer drug delivery.

A generalizable strategy for crosslinkable albumin-based hydrogels and application as potential anti-tumor nanoplatform.

Albumin-based hydrogels have emerged as promising nanoparticle systems for the effective delivery of hydrophobic anticancer drugs. Anti-cancer drugs often cause some adverse effects, such as toxicity and rapid clearance by mononuclear phagocytic systems. Herein, a new strategy of synthesizing N-hydroxysuccinimide (NHS)-activated linker to form crosslinkable albumin-based hydrogels (CABH) is reported. The CABH favored physiochemical characteristics improvement of doxorubicin (Dox) and drug release. The CABH was constructed depending on the crosslinking reaction between NHS activated glycerol and albumin. The size of CABH was approximately 200nm examined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was found that the particle size and size distribution of the CABH remained stable in neutral PBS for 1week. Dox loaded CABH would be controllably released in weak acidic environment verified by in vitro release and in vitro cell imaging. The Dox loaded hydrogel results in significant killing in the case of acidic culture medium. Our work provides a crosslinking method to formulate albumin nanoplatform and improve the size, stability, drug loading capacity and controlled release, which throws light on the potential application in drug delivery.

The Construction of Polyphotocage Platform for Anticancer Photochemotherapy

AbstractPhotocages enable the precise activation of molecular function with light in many research fields, such as anticancer treatment, where remote spatiotemporal control over the release of an active drug is needed. However, the poor physiological stability and tumor accumulation of conventional small molecular photocages are significant obstacles to developing efficient therapy in vivo. In this study, a new concept of “polyphotocage” is proposed through photocage–polymer hybrid macromolecular engineering. Photoresponsive Ru complex photocage is designed and fused with PEGylated polycarbonates, resulting in the polyphotocage. Various anticancer drugs can be readily conjugated to the polyphotocage via coordination linkage, which can be cut off to release drugs by red light. The polyphotocages can self‐assemble into nanoparticles, which enhances the stability of the Ru photocage and demonstrates the efficient accumulation in different‐sized tumorswith a high signal‐to‐background ratio. Furthermore, rapid cellular internalization and mitochondrial anchoring capability allowed the polyphotocages to deliver drugs into the mitochondria, which induces mitochondrial dysfunction and cell death. These properties ensure the effective delivery of anticancer drugs to solid tumors and multiple tiny tumors, ultimately inhibiting tumor proliferation. This strategy of polyphotocages provides a new platform for the future design of drug‐delivery systems for cancer photochemotherapy.

Ru(II)(ƞ6-p-cymene) Conjugates Loaded onto Graphene Oxide: An Effective pH-Responsive Anticancer Drug Delivery System.

Graphene oxide-based nanodrug delivery systems are considered one of the most promising platforms to deliver therapeutic drugs at the target site. In this study, Ru(II)(ƞ6-p-cymene) complexes containing the benzothiazole ligand were covalently anchored on graphene oxide using the ultrasonication method. The nanoconjugates GO-NCD-1 and GO-NCD-2 were characterized by FT-IR, UV-visible, 1H NMR, TGA, SEM, and TEM techniques, which confirmed the successful loading of both the complexes (NCD 1 and NCD 2) on the carrier with average particle diameter sizes of 17 ± 6.9 nm and 25 ± 6.5 nm. In vitro DNA binding studies of the nanoconjugates were carried out by employing various biophysical methods to investigate the binding interaction with the therapeutic target biomolecule and to quantify the intrinsic binding constant values useful to understand their binding affinity. Our results suggest (i) high Kb and Ksv values of the graphene-loaded conjugates (ii) effective cleavage of plasmid DNA at a lower concentration of 7.5 µM and 10 µM via an oxidative pathway, and (iii) fast release of NCD 2 at an acidic pH that could have a good impact on the controlled delivery of drug. It was found that 90% of the drug was released in an acidic pH (5.8 pH) environment in 48 h, therefore suggesting pH-responsive behavior of the drug delivery system. Molecular docking, DFT studies, and cytotoxicity activity against three cancer cell lines by SRB assay were also performed.

Folic acid-functionalized cerium oxide nanoparticles as smart nanocarrier for pH-responsive and targeted delivery of Morin in breast cancer therapy

• A novel FA-tagged CeO 2 NPs were synthesized for targeting human breast cancer cells. • The NPs were loaded with morin, a natural flavonoid to form Morin-CeO 2 -NH-FA nanohybrids. • Morin-CeO 2 -NH-FA nanohybrids exhibited pH-dependent drug release property. • Morin-CeO 2 -NH-FA nanohybrids showed significant anticancer effect both in vitro and in vivo . • Morin-CeO 2 -NH-FA nanohybrids did not exhibit any systemic toxicity. Nanoceria (CeO 2 NP) has emerged as a promising carrier for effective delivery of various anticancer drugs. Herein, folic acid (FA) conjugated and amine-functionalized CeO 2 NPs (CeO 2 -NH-FA) have been synthesized for targeted and controlled delivery of Morin (a natural flavonoid) towards folic acid overexpressed breast cancer cells. Morin was successfully loaded onto the surface of CeO 2 -NH-FA via metal ion-ligand coordination bonds to form Morin-CeO 2 -NH-FA nanohybrids. The as synthesized nanohybrid exhibited nearly spherical shape with an average diameter of ∼ 2–3 nm. Moreover, the nanohybrid displayed drug loading content of ∼ 10 % along with pH-responsive drug release behaviour. The nanohybrids exhibited significant cytotoxic effect towards human breast cancer (MCF-7) cells via the generation of intracellular reactive oxygen species (ROS) which subsequently induced mitochondria-dependent apoptotic cell death. In addition, the nanohybrids also triggered potential anti-migratory effect. The in vivo results also revealed the highest anticancer effect of the Morin-CeO 2 -NH-FA nanohybrids in tumor-bearing mice as compared with free Morin and CeO 2 -NH-FA. Furthermore, Morin-CeO 2 -NH-FA nanohybrid did not show any significant change in serum biochemical parameters. To gain possible mechanistic pathway, we carried out molecular docking study of Morin with Bcl-2 protein which revealed that Morin can bind to Bcl-2 with an affinity of −7.1 kCal/mol. The pronounced anticancer effect of the nanohybrid towards breast cancer cells is mainly ascribed to the combined cytotoxic effect of both Morin as well as nanoceria. Overall, our study represents Morin-CeO 2 -NH-FA nanohybrid as a potential drug delivery vehicle with improved therapeutic efficacy against cancer.

A dual drug delivery platform based on thermo-responsive polymeric micelle capped mesoporous silica nanoparticles for cancer therapy

The combination of organic polymers and inorganic nanoparticles to design intelligent nanocarriers is of great significance for effective delivery of anticancer drugs to tumor cells for therapy. Herein, we have prepared a thermo-responsive micelle as a “gatekeeper” to attach on the surface of mesoporous silica nanoparticle (MSN) through disulfide bonds. DOX was encapsulated in both nanocarriers, resulting in a pH/redox/temperature responsive dual drug delivery platform ([email protected]2[email protected], abbreviated as DMSFPD) with high loading capacity and excellent stimuli-responsive performance for cancer therapy. The cumulative release curve in vitro indicated that DOX could be controllably released from DMSFPD. With the elevated temperature at 40 °C, the uncapping ofF127-PCL250 (FP250) micelle from MSN after GSH stimulus and the shrinkage of FP250 micelle caused a fast release of DOX from both MSN and micelle, which greatly increased the drug concentration immediately. The intracellular uptake and cytocompatibility demonstrated that MSN-S2-F127-PCL250 (MSFP250) could be efficiently endocytosed and have shown favorable biocompatibility in both normal and tumoral cells. Cytotoxicity results illustrated that DMSFPD could significantly kill different kinds of cancer cells. Therefore, this dual drug delivery capping platform provides a new and promising strategy for cancer therapy.

β-cyclodextrin/alginate nanoparticles encapsulated 5-fluorouracil as an effective and safe anticancer drug delivery system

Although 5-Fluorouracil (5-FU) is one of the most frequently used cytotoxic chemotherapy drugs in the treatment of cancer, it possesses a short biological half-life and toxic side effects against normal healthy cells. In this work, β-cyclodextrin/alginate (β-CD/Alg) nanoparticles loaded with 5-fluorouracil (5-FU) were prepared to evaluate release properties and bioactivity in different pH media. Stable nanocomposites with the best loading efficiency (36%) and encapsulation efficiency (90%) were successfully fabricated. The size of the nanocomposite solution was determined via dynamic light scattering (DLS) to be in the range 30–120 nm with a mean size of 70 nm, while TEM images showed the particle size of the nanocomposite to be in the range 30–80 nm with a mean size of 50 nm. The release profile of 5-FU in a simulated gastric fluid (pH 1.2) was much lower than in a simulated colorectal fluid (pH 7.4). The release behaviour of 5-FU from the nanocomposite was confirmed by the change in morphology in the pH media. A cytotoxicity assay indicated that the nanocomposite is an effective delivery system for 5-FU with strong antiproliferative activity against MCF-7 cells and negligible effects on normal healthy cells.

Synthesis of Novel Conjugated Linoleic Acid (CLA)-Coated Superparamagnetic Iron Oxide Nanoparticles (SPIONs) for the Delivery of Paclitaxel with Enhanced In Vitro Anti-Proliferative Activity on A549 Lung Cancer Cells.

The application of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as a nanomedicine for Non-Small Cell Lung Carcinoma (NSCLC) can provide effective delivery of anticancer drugs with minimal side-effects. SPIONs have the flexibility to be modified to achieve enhanced oading of hydrophobic anticancer drugs such as paclitaxel (PTX). The purpose of this study was to synthesize novel trans-10, cis-12 conjugated linoleic acid (CLA)-coated SPIONs loaded with PTX to enhance the anti-proliferative activity of PTX. CLA-coated PTX-SPIONs with a particle size and zeta potential of 96.5 ± 0.6 nm and −27.3 ± 1.9 mV, respectively, were synthesized. The superparamagnetism of the CLA-coated PTX-SPIONs was confirmed, with saturation magnetization of 60 emu/g and 29 Oe coercivity. CLA-coated PTX-SPIONs had a drug loading efficiency of 98.5% and demonstrated sustained site-specific in vitro release of PTX over 24 h (i.e., 94% at pH 6.8 mimicking the tumor microenvironment). Enhanced anti-proliferative activity was also observed with the CLA-coated PTX-SPIONs against a lung adenocarcinoma (A549) cell line after 72 h, with a recorded cell viability of 17.1%. The CLA-coated PTX-SPIONs demonstrated enhanced suppression of A549 cell proliferation compared to pristine PTX, thus suggesting potential application of the nanomedicine as an effective site-specific delivery system for enhanced therapeutic activity in NSCLC therapy.

Transferrin/folate dual-targeting Pluronic F127/poly(lactic acid) polymersomes for effective anticancer drug delivery

A novel dual-targeting Pluronic/poly(lactic acid) polymersome containing transferrin and folic acid ligands (Tf/FA-F127-PLA) has been designed to study its application in the targeted drug delivery system. Both biotin and folic acid conjugated Biotin/FA-F127-PLA polymersomes (Ps) were prepared as the precursor. The dual-targeting behaviors of Tf/FA-F127-PLA over C6 glioma cells were then fulfilled through connecting the precursor with biotinylated transferrin by using a three-step biotin-avidin technique. Paclitaxel (PTX) was loaded successfully into Biotin/FA-F127-PLA and showed a burst release followed by a slow-release process in vitro. It was also obtained that Tf/FA-F127-PLA had higher cytotoxicity and cellular uptake amount than non-targeted and single-targeted Ps did. These results could be because more PTX-loaded Tf/FA-F127-PLA Ps entered C6 cells through both FA-folate receptor (FR) and Tf-transferrin receptor (TfR) specific affinity and thus possessed the better anti-tumor ability. It was further proved that the uptake of Ps by C6 cells was through the endocytosis related to clathrin, caveolae, lysosome, etc. Furthermore, it was demonstrated that the uptake of dual-targeting Tf/FA-F127-PLA Ps by C6 cells was related to the endocytosis mediated by both FR and TfR. These findings indicated that dual-targeting Tf/FA-F127-PLA Ps could be a potential carrier in targeted drug delivery systems.

Fabrication of pH/Redox Dual-Responsive Mixed Polyprodrug Micelles for Improving Cancer Chemotherapy.

In this work, we prepared pH/redox dual-responsive mixed polyprodrug micelles (MPPMs), which were co-assembled from two polyprodrugs, namely, poly(ethylene glycol) methyl ether-b-poly (β-amino esters) conjugated with doxorubicin (DOX) via redox-sensitive disulfide bonds (mPEG-b-PAE-ss-DOX) and poly(ethylene glycol) methyl ether-b-poly (β-amino esters) conjugated with DOX via pH-sensitive cis-aconityl bonds (mPEG-b-PAE-cis-DOX) for effective anticancer drug delivery with enhanced therapeutic efficacy. The particle size of MPPMs was about 125 nm with low polydispersity index, indicating the reasonable size and uniform dispersion. The particle size, zeta-potential, and critical micelle concentration (CMC) of MPPMs at different mass ratios of the two kinds of polyprodrugs were dependent on pH value and glutathione (GSH) level, suggesting the pH and redox responsiveness. The drug release profiles in vitro of MPPMs at different conditions were further studied, showing the pH—and redox-triggered drug release mechanism. Confocal microscopy study demonstrated that MPPMs can effectively deliver doxorubicin molecules into MDA-MB-231 cells. Cytotoxicity assay in vitro proved that MPPMs possessed high toxic effect against tumor cells including A549 and MDA-MB-231. The results of in vivo experiments demonstrated that MPPMs were able to effectively inhibit the tumor growth with reduced side effect, leading to enhanced survival rate of tumor-bearing mice. Taken together, these findings revealed that this pH/redox dual-responsive MPPMs could be a potential nanomedicine for cancer chemotherapy. Furthermore, it could be a straightforward way to fabricate the multifunctional system basing on single stimuli-responsive polyprodrugs.

Amplification of anticancer efficacy by co-delivery of doxorubicin and lonidamine with extracellular vesicles

Chemotherapy is commonly used for the treatment of lung cancer, but strong side effects and low treatment efficacy limit its clinical application. Here, extracellular vesicles (EVs) as natural drug delivery carriers were used to load conventional anticancer drug doxorubicin (DOX) and a chemosensitizer lonidamine (LND). Two types of EVs with different sizes (16k EVs and 120k EVs) were prepared using different centrifugation forces. We found that co-delivery of DOX and LND with both EVs enhanced the cytotoxicity and reduced the dose of the anticancer drug significantly in vitro. Effective delivery of anti-cancer drugs to cancer cells was achieved by direct fusion of EVs with the plasma membrane of cancer cells. On the other hand, DOX and LND inhibited cancer cell proliferation by increasing DNA damage, suppressing ATP production, and accelerating ROS generation synergistically. DOX and LND loaded EVs were also applied to the mouse lung cancer model and exhibited significant anticancer activity. In vivo study showed that smaller EVs exhibited higher anticancer efficiency. In conclusion, the co-delivery of the anticancer drug and the chemosensitizer with EVs may have potential clinical applications for cancer therapy.

Functionalized Graphene Oxide as Drug Delivery Systems for Platinum Anticancer Drugs.

Graphene Oxide, prepared by the modified Hummer's method, was modified with a series of high polymers (polyethyleneimine, polyethylene glycol, chitosan) and Folic Acid for the delivery of platinum anticancer drugs including Cisplatin, Carboplatin, Oxaliplatin and Eptaplatin. Nanocarriers were successfully prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. Measurement of drug loading efficiency showed that these nanocarriers had the ability for effective delivery of the platinum anticancer drugs. The Maximum loading ratios of Cisplatin, Carboplatin, Oxaliplatin and Eptaplatin were 25.72, 161.08, 345.21 and 67.80μg/mg. Drug release experiments in the acid environment showed that the cumulative release rate of platinum anticancer drugs from nanocarriers was higher than that in the neutral environment. The cumulative release of all three nanocarriers in the acid environment reached above 60%. In vitro cytotoxicity assay showed that those nanocarriers had a low toxicity. The cell viability rates were above 80% for all three nanocarriers. Investigation of the anticancer activity in vitro showed that those drug delivery systems had the ability to inhibit the growth of the SKOV3 cell line. These results showed that those nanocarriers were suitable for the delivery of platinum anticancer drugs. Providing preliminary advice on the potential application of the combination of platinum anticancer drugs and the functionalized Graphene Oxide nanocarriers.

Alkyl Chain Length in Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers Regulates the Delivery of Hydrophobic Molecules: A Case of the Biodistribution and the Photodynamic Activity of the Photosensitizer Hypericin.

Self-assembled nanostructures of amphiphilic gradient copoly(2-oxazoline)s have recently attracted attention as promising delivery systems for the effective delivery of hydrophobic anticancer drugs. In this study, we have investigated the effects of increasing hydrophobic side chain length on the self-assembly of gradient copolymers composed of 2-ethyl-2-oxazoline as the hydrophilic comonomer and various 2-(4-alkyloxyphenyl)-2-oxazolines as hydrophobic comonomers. We show that the size of the formed polymeric nanoparticles depends on the structure of the copolymers. Moreover, the stability and properties of the polymeric assembly can be affected by the loading of hypericin, a promising compound for photodiagnostics and photodynamic therapy (PDT). We have found the limitation that allows rapid or late release of hypericin from polymeric nanoparticles. The nanoparticles entering the cells by endocytosis decreased the hypericin-induced PDT, and the contribution of the passive process (diffusion) increased the probability of a stronger photoeffect. A study of fluorescence pharmacokinetics and biodistribution revealed differences in the release of hypericin from nanoparticles toward the quail chorioallantoic membrane, a preclinical model for in vivo studies, depending on the composition of polymeric nanoparticles. Photodamage induced by PDT in vivo well correlated with the in vitro results. All formulations studied succeeded in targeting hypericin at cancer cells. In conclusion, we demonstrated the promising potential of poly(2-oxazoline)-based gradient copolymers for effective drug delivery and sequential drug release needed for successful photodiagnostics and PDT in cancer therapy.

Electromagnetic Field-Programmed Magnetic Vortex Nanodelivery System for Efficacious Cancer Therapy.

Effective delivery of anticancer drugs into the nucleus for pharmacological action is impeded by a series of intratumoral transport barriers. Despite the significant potential of magnetic nanovehicles in electromagnetic field (EF)‐activated drug delivery, modularizing a tandem magnetoresponsive activity in a one‐nanoparticle system to meet different requirements at both tissue and cellular levels remain highly challenging. Herein, a strategy is described by employing sequential EF frequencies in inducing a succession of magnetoresponses in the magnetic nanovehicles that aims to realize cascaded tissue penetration and nuclear accumulation. This nanovehicle features ferrimagnetic vortex‐domain iron oxide nanorings coated with a thermo‐responsive polyethylenimine copolymer (PI/FVIOs). It is shown that the programmed cascading of low frequency (Lf)‐EF‐induced magnetophoresis and medium frequency (Mf)‐EF‐stimulated magneto‐thermia can steer the Doxorubicin (DOX)‐PI/FVIOs to the deep tissue and subsequently trigger intracellular burst release of DOX for successful nuclear entry. By programming the order of different EF frequencies, it is demonstrated that first‐stage Lf‐EF and subsequent Mf‐EF operation enables DOX‐PI/FVIOs to effectively deliver 86.2% drug into the nucleus in vivo. This nanodelivery system empowers potent antitumoral activity in various models of intractable tumors, including DOX‐resistant MCF‐7 breast cancer cells, triple‐negative MDA‐MB‐231 breast cancer cells, and BxPC‐3 pancreatic cancer cells with poor permeability.

Abstract 279: Transient opening of the blood brain barrier by Tumor Treating Fields (TTFields)

Abstract Introduction Alternating electric fields of intermediate frequency and low intensity, known as Tumor Treating Fields (TTFields), are an effective and clinically approved approach for treatment of glioblastoma (GBM). The optimal frequency for treatment of glioma cells based on the cytotoxic response is at 200 kHz. Combination of TTFields with chemotherapy appears to be synergistic with further increase in overall survival of patients with GBM, beyond that with chemotherapy alone. The blood brain barrier (BBB) limits delivery of a majority of drugs to the brain thus limiting treatment options for GBM patients. Recent in vitro studies suggest that TTFields applied at 100 kHz can disturb the BBB. In this study, we investigated the potential use of TTFields to transiently disturb the BBB in animal models. Methods BBB permeation was tested in healthy rats subsequently to 100 kHz TTFields or sham (heat) application to the rat head. BBB permeability was analyzed by several staining agents: (1) Evans Blue (EB) that was quantified at 610 nm in brain homogenates; (2) 4 kDa TRITC-dextran (TD) that was quantified based on fluorescence intensity in brain cryosections; and (3) the MRI contrast agent Gd-DTPA. Accumulation and clearance of Gd-DTPA were tracked by serial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In addition, brain sections were stained for claudin-5, occludin, PECAM-1 and immunoglobulin G (IgG). BBB permeation induced by TTFields was further evaluated in rats orthotopically bearing F98 glioma cells and treated with TTFields at 100 kHz in combination with the chemotherapeutic drug paclitaxel (PTX) for a duration of 72 h. Tumor cell proliferation was assessed by Ki67 staining and the tumor volume was measured by T2 weighted MRI. Results BBB permeation of EB and TD staining agents was observed in the brains of healthy rats after TTFields application. Moreover, brain cryosections displayed delocalization of claudin-5 and occludin, but not of PECAM-1. Accumulation of IgG in the brain parenchyma was also noted. Confirming these observations, DCE-MRI post-TTFields treatment showed accumulation of Gd in the brain. Return to normal BBB integrity was detected 96 h after TTFields treatment cessation, indicating the effect was transient and reversible. In GBM-induced rats, the combination of PTX (a drug which normally does not cross the BBB) with TTFields significantly decreased tumor cell proliferation and tumor volume compared to animals treated with TTFields alone, sham alone, or sham combined with PTX. Conclusions Administration of 100 kHz TTFields to the brain of rats led to transient alterations in BBB integrity and permeability, allowing increased uptake of combination chemotherapy. These data indicate that TTFields treatment may be a feasible, novel clinical strategy for transient opening of the BBB to allow for enhanced and more effective delivery of permeable and non-permeable anticancer drugs to the brain. Citation Format: Catherine Tempel Brami, Ellaine Salvador, Almuth F. Kessler, Malgorzata Burek, Tali Voloshin, Moshe Giladi, Ralf-Ingo Ernestus, Mario Löhr, Carola Förster, Carsten Hagemann. Transient opening of the blood brain barrier by Tumor Treating Fields (TTFields) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 279.

Anticancer and Antimicrobial Activity Evaluation of Cowpea-Porous-Starch-Formulated Silver Nanoparticles

Health issues involving inadequate treatment of diseases such as cancer and microbial infections continue to be the subject of much ongoing recent research. Biosynthesized silver nanoparticles (AgNPs) were characterized using Transmission Electron Microscopy (TEM), Zeta Sizer, Ultraviolet (UV), and Fourier Transform Infrared (FTIR) spectroscopy. Their antimicrobial activity was evaluated on selected Gram-positive and Gram-negative bacterial strains, using the disc diffusion and broth dilution assays. Cell viability profiles were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis studies on selected human noncancer and cancer cells. The biosynthesized AgNPs were evaluated to be spherical clusters, with sizes between 40 and 70 nm. The absorption peak at 423 nm and the presence of polyphenols confirmed the synthesis and stabilization of these tested AgNPs. The AgNPs showed a good stability of −23.9 ± 1.02 mV. Good antimicrobial activity (6.0–18.0 mm) was seen on all tested bacteria at a minimum inhibitory concentration (MIC) ranging from 5 to 16 μg/ml, with the highest activity seen against Gram-negative Escherichia coli (18 ± 0.5 mm), and the lowest activity was seen against Gram-positive Listeria monocytogenes (6.0 ± 0.4 mm) after treatment with the AgNPs. These NPs showed a concentration-dependent and cell-specific cytotoxicity with low IC50 values (41.7, 56.3, and 63.8 μg/ml). The NPs were well tolerated by tested cells as indicated by a more than 50% cell viability at the high dose tested and low apoptotic indices (<0.2). These findings indicated that these biosynthesized AgNPs showed great potential as effective antibacterial agents and anticancer drug delivery modalities.