Cytotoxic and antitumor effect of fibrinogen-methotrexate conjugate

Hybrid Cyanine/Methotrexate Nanoparticles for Synergistic PDT/Chemotherapy of Breast Cancer

Typically, nanomedicine was prepared using a nanocarrier to load cargo for specific purposes. In this work, a carrier-free nanosystem for imaging and photodynamic (PDT)/chemo combination therapy was developed using simple self-assembly of a dye and a chemotherapeutic agent. The resulting nanoparticles (I₂-IR783/MTX@NPs) exhibited a spherical morphology with a size of 240.6 ± 2.5 nm. I₂-IR783/MTX@NPs had substantial internalization in 4T1 murine breast cancer cells and showed a synergistic anticancer effect after NIR light irradiation. Additionally, the 3D tumor model exhibits the same phototoxicity of nanoparticles as a 2D cell culture. The PDT efficiency of the nanosystem in the physiological environment was confirmed by the detection of intracellular reactive oxygen species as well as the live/dead viability/cytotoxicity assay following NIR light exposure. In addition, optical coherence tomography (OCT) was used as an alternative tool to monitor the response after treatment. Therefore, I₂-IR783/MTX@NPs show great potential use in theranostic application for breast cancer PDT-chemotherapy.

Current understandings and clinical translation of nanomedicines for breast cancer therapy

Breast cancer is one of the most frequently diagnosed cancers that is threatening women's life. Current clinical treatment regimens for breast cancer often involve neoadjuvant and adjuvant systemic therapies, which somewhat are associated with unfavorable features. Also, the heterogeneous nature of breast cancers requires precision medicine that cannot be fulfilled by a single type of systemically administered drug. Taking advantage of the nanocarriers, nanomedicines emerge as promising therapeutic agents for breast cancer that could resolve the defects of drugs and achieve precise drug delivery to almost all sites of primary and metastatic breast tumors (e.g. tumor vasculature, tumor stroma components, breast cancer cells, and some immune cells). Seven nanomedicines as represented by Doxil® have been approved for breast cancer clinical treatment so far. More nanomedicines including both non-targeting and active targeting nanomedicines are being evaluated in the clinical trials. However, we have to realize that the translation of nanomedicines, particularly the active targeting nanomedicines is not as successful as people have expected. This review provides a comprehensive landscape of the nanomedicines for breast cancer treatment, from laboratory investigations to clinical applications. We also highlight the key advances in the understanding of the biological fate and the targeting strategies of breast cancer nanomedicine and the implications to clinical translation.

Hydroxyethylcellulose as a methotrexate carrier in anticancer therapy

Clinical and experimental cancer therapy is multifaceted; one such facet is the use of drug carriers. Drug carriers are various nano- and macromolecules, e.g., oligosaccharides, proteins, and liposomes. The present study aimed to verify the suitability of cellulose as a carrier for methotrexate (MTX). Hydroxyethylcellulose, with a molecular weight of 90 kDa and soluble in water, was used. Methotrexate was linked to cellulose by methyl ester bonds. A conjugate containing on average 9.5 molecules of MTX per molecule of cellulose was developed. Gel filtration HPLC analysis showed that the conjugate contained approximately 2% free drug. Dynamic light scattering analysis showed an increase in the polydispersity of the conjugate. The degradation of the conjugate in phosphate buffer and plasma followed first-order kinetics. The conjugate showed the lowest stability (half-life 154 h) in plasma. The conjugate showed 10-fold lower cytotoxicity to the 4 T1 mammary tumour cell line than the free drug. In the in vivo experiment to treat orthotopically implanted mammary tumours, the conjugate and the free drug, both applied intravenously, showed maximum inhibition of tumour growth of 48.4% and 11.2%, respectively. In conclusion, cellulose, which is a non-biodegradable chain glucose polymer, can be successfully used as a drug carrier, which opens up new research perspectives.

Ceramic core with polymer corona hybrid nanocarrier for the treatment of osteosarcoma with co-delivery of protein and anti-cancer drug

For the treatment of metastatic bone cancer, local delivery of therapeutic agents is preferred compared to systemic administration. Delivery of an anti-cancer drug and a protein that helps in bone regeneration simultaneously is a challenging approach. In this study, a nanoparticulate carrier which delivers a protein and an anti-cancer drug is reported. Bovine serum albumin (BSA) as a model protein was loaded into hydroxyapatite (HA) nanoparticles (NPs) and methotrexate (MTX) conjugated to poly(vinyl alcohol) was coated onto BSA-loaded HA NPs. Coating efficiency was in the range of 10-17 wt%. In vitro drug release showed that there was a steady increase in the release of both BSA and MTX with 76% of BSA and 88% of MTX being released in 13 days. Cytotoxicity studies of the NPs performed using human osteosarcoma (OMG-63) cell line showed the NPs were highly biocompatible and exhibited anti-proliferative activity in a concentration-dependent manner.

Human alveolar epithelial cell responses to core-shell superparamagnetic iron oxide nanoparticles (SPIONs)

Superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared and coated with positively (-NH3(+)) and negatively (-COO(-)) charged shells. These NPs, as well as their "bare" precursor, which actually contain surface hydroxyl groups, have been characterized in vitro, and their influence on a human epithelial cell line has been assessed in terms of cell metabolic activity, cellular membrane lysis, mitochondrial activity, and reactive oxygen species production. Their physicochemical characterizations and protein-nanoparticle interactions have been determined using dynamic light scattering, high-resolution transmission electron microscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectrometry, and Coomassie Blue fast staining. Cell-SPION interactions have been determined by PrestoBlue resazurin-based, Trypan Blue dye exclusion-based, and MTS cell proliferation assays as well as by reactive oxygen species determination. The results show that different surface characteristics cause different protein corona and cell responses. Some proteins (e.g., albumin) are adsorbed only on positively charged coatings and others (e.g., fibrinogen) only on negatively charged coating. No cell deaths occur, but cell proliferation is influenced by surface chemistry. Proliferation reduction is dose dependent and highest for bare SPIONs. Negatively charged SPIONs were the most biocompatible.

Human serum albumin and p53-activating peptide fusion protein is able to promote apoptosis and deliver fatty acid-modified molecules

Therapeutic peptides offer a high degree of specificity, potency, and low toxicity; making them promising candidates for cancer therapy. Despite these advantages, a number of hurdles, such as poor serum stability and inefficient cellular penetration, must be overcome. Fusing a therapeutic peptide to human serum albumin (HSA) is a common approach to extend the serum stability of a peptide that binds to extracellular receptors. However, no study has shown that this approach can be applied to target intracellular proteins. Here we demonstrate the feasibility of using a recombinant human serum albumin (rHSA) fusion protein to simultaneously deliver two types of molecules: a peptide capable of binding an intracellular target, as well as fatty acid (FA)-modified FITC (FA-FITC). Two peptides reported to disrupt the intracellular p53 and MDM2/MDMX interaction were fused to the C-terminal of HSA. Cellular and biochemical studies indicate that rHSA fusion proteins were efficiently taken up by SJSA-1 cells and retained MDM2- and MDMX-binding activity. By inducing the accumulation of p53, both fusion proteins promoted efficient cytotoxicity in SJSA-1 cells via caspase activation. Long chain fatty acid (LCFA) transportation is an essential endogenous function of HSA. This study also demonstrates that rHSA fusion proteins formed highly stable complexes with FA-FITC via non-covalent interactions. FA-FITC complexed with HSA could be internalized efficiently and rHSA-P53i and rHSA-PMI retained apoptotic activity as complex components. It is expected that such an approach can ultimately be used to facilitate intracellular delivery of two anticancer therapeutics, each with distinct but complimentary mechanisms, to achieve synergistic efficacy.

Evaluation of small ligand-protein interactions by using T7 RNA polymerase with DNA-modified ligand

The interaction between proteins and ligands was evaluated by T7 RNA polymerase transcription with a DNA-modified ligand. The principle of this method is suppression of T7 RNA polymerase transcription by binding of a protein to small ligand modified by conjugation with a T7 RNA polymerase promoter. To demonstrate proof of principle, biotin or antifolate methotrexate was modified by covalent attachment of a T7 RNA promoter. Using these T7 RNA promoter-modified ligands, T7 RNA polymerase transcriptions were performed in the presence or absence of an anti-biotin antibody or recombinant human dihydrofolate reductase, respectively. Transcription was suppressed in the presence of each binding protein plus its modified ligand, but not in the absence of the binding protein.

Alternative drug formulations of docetaxel: a review

The anticancer drug docetaxel (Taxotere) is formulated in the nonionic surfactant polysorbate 80 (Tween 80). Early in the clinical development of docetaxel, it became clear that docetaxel administration is associated with the occurrence of unpredictable (acute) hypersensitivity reactions and cumulative fluid retention. These side-effects have been attributed, in part, to the presence of polysorbate 80 and have consequently initiated research focused on the development of a less-toxic, better-tolerated polysorbate 80-free formulation of docetaxel. More recently, there is an increasing interest in developing a (polysorbate 80-free) docetaxel formulation that selectively targets malignant tissue, thereby increasing efficacy while decreasing the occurrence of side-effects related to wide and nonspecific body distribution. This review aims to discuss the preclinical and clinical results of pharmaceutical strategies [PEGylated (immuno)liposomal docetaxel, docetaxel-fibrinogen-coated olive oil droplets, docetaxel encapsulated nanoparticle-aptamer bioconjugates, submicronic dispersion formulation] to develop an alternative, solvent-free, delivery form for docetaxel characterized by increased efficacy and decreased toxicity.

Overcoming methotrexate resistance in breast cancer tumour cells by the use of a new cell-penetrating peptide

Resistance to chemotherapy limits the effectiveness of anti-cancer drug treatment. Here, we present a new approach to overcome the setback of drug resistance by designing a conjugate of a cell-penetrating peptide and the cytostatic agent methotrexate (MTX). Two different peptides, YTA2 and YTA4, were designed and their intracellular delivery efficiency was characterized by fluorescence microscopy and quantified by fluorometry. MTX was conjugated to the transport peptides and the ability of the peptide-MTX conjugates to inhibit dihydrofolate reductase, the target enzyme of MTX, was found to be 15 and 20 times less potent than MTX. In addition, in vitro studies were performed in a drug resistant cell model using the 100-fold MTX resistant breast cancer cells MDA-MB-231. At a concentration of 1 microM, the peptide-MTX conjugates were shown to overcome MTX resistance and kill the cells more efficiently than MTX alone. Estimated EC50's were determined for MTX, MTX-YTA2 and YTA2 to be 18.5, 3.8 and 20 microM, respectively. In summary, cell-penetrating peptide conjugation of MTX is a new way of increasing delivery, and thereby, the potency of already well-characterized therapeutic molecules into drug resistant tumour cells.

Growth inhibition, drug load, and degradation studies of gelatin/methotrexate conjugates

Macromolecular gelatin-methotrexate conjugates have potential therapeutic advantages over the free drug. Conjugates with MTX:gelatin molar ratios (MR) ranging from 1:1 to 27:1 were examined for cell growth inhibition, stability, degradation, and methotrexate (MTX) release. Conjugate growth inhibition was less than that of free MTX whose IC(50) value of 1.3 x 10(-8) M was about 10-fold less. Cell uptake of fluorescein labeled gelatin (145 kD) was observed by 24-30 h. Higher MR conjugates produced less growth inhibition, measurably greater stability at pH 7.4 based on MTX release, and had less gelatin degradation in the conjugate by the lysosomal enzyme Cathepsin B (Cat B) compared to low MR conjugates. Cat B conjugate degradation was greater at the in vitro lysosomal pH of 4.8 than the intra-tumor pH of 6.5. The presence of Cat B did not meaningfully affect MTX release, but less MTX was released at pH 4.8 than pH 6.5. The maximum MTX release was a relatively low 7% after 72 h at pH 6.5 for the low MR conjugate. Low molecular weight conjugate fragments were also produced and were also influenced by pH and MR. Reduced growth inhibition by high MR conjugates may be due to a hindered enzymatic degradation in the lysosomes. A strong peptide conjugate bond at lysosomal pH and a 24-30 h delayed gelatin uptake may contribute to reduced growth inhibition of the conjugate compared to free MTX. MTX release under these in vitro conditions occurs by aqueous hydrolysis, not by Cat B cleavage of the conjugate bond.

Characterization and in vitro methotrexate release from methotrexate/gelatin conjugates of opposite conjugate bond polarity

PURPOSE

Our laboratory has previously prepared gelatin/ methotrexate (MTX) conjugates containing mixed conjugation sites and by-product crosslinking, both of which may alter conjugate effectiveness. In this study, we prepared and evaluated gelatin/MTX conjugates having specific conjugate bond sites and minimal by-product crosslinking.

METHODS

Opposite polarity conjugates were produced by coupling gelatin having blocked amino groups with MTX (G-MTX) and by coupling MTX having blocked amino groups with gelatin (M-GEL) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide HCl. Amino groups were blocked using citraconic anhydride and deblocked under acidic conditions. Gelatin and MTX contents were determined spectrophotometrically. The stability of each conjugate was determined by evaluating their in vitro release of MTX in isotonic buffer at pH 7.4 and 37 degrees C for 7 days.

RESULTS

The G-MTX and M-GEL conjugates contained 21 and 1.2 mole MTX/mole gelatin and released 12 and 17% MTX by 7 days resulting in pseudo-first order release rate constants of 0.76x10(-3) and 1.0x10(-3) hr(-1), respectively. Alternate MTX species (< or =10%) were detected during the release study and were attributed to low molecular weight gelatin/MTX fragments and MTX polymers.

CONCLUSIONS

Gelatin/MTX conjugates having opposite conjugate bond polarities and minimal by-product crosslinking have been produced and slowly released MTX by hydrolytic cleavage indicating good stability for future cell culture studies.