Shape complementarity processes for ultrashort-burst sensitive M13-PEG-WS2-powered MCF-7 cancer cell sensors.

Biomarkers have the potential to be utilized in disease diagnosis, prediction and monitoring. The cancer cell type is a leading candidate for next-generation biomarkers. Although traditional digital biomolecular sensor (DBS) technology has shown to be effective in assessing cell-based interactions, low cell-population detection of cancer cell types is extremely challenging. Here, we controlled the electrical signature of a two-dimensional (2D) nanomaterial, tungsten disulfide (WS2), by utilizing a combination of the Phage-integrated Polymer and the Nanosheet (PPN), viz., the integration of the M13-conjugated polyethylene glycol (PEG) and the WS2, through shape-complementarity phenomena, and developed a sensor system, i.e., the Phage-based DBS (P-DBS), for the specific, rapid, sensitive detection of clinically-relevant MCF-7 cells. The P-DBS attains a detection limit of 12 cells per µL, as well as a contrast of 1.25 between the MCF-10A sample signal and the MCF-7 sample signal. A reading length of 200 µs was further achieved, along with a relative cell viability of ∼100% for both MCF-7 and MCF-10A cells and with the PNN. Atomistic simulations reveal the structural origin of the shape complementarity-facilitated decrease in the output impedance of the P-DBS. The combination of previously unreported exotic sensing materials and digital sensor design represents an approach to unlocking the ultra-sensitive detection of cancer cell types and provides a promising avenue for early cancer diagnosis, staging and monitoring.

Downregulation of Dihydrotestosterone and Estradiol Levels by HEXIM1.

We have previously reported that hexamethylene bis-acetamide inducible protein 1 (HEXIM1) inhibits the activity of ligand-bound estrogen receptor α (ERα) and the androgen receptor (AR) by disrupting the interaction between these receptors and positive transcriptional elongation factor b (P-TEFb) and attenuating RNA polymerase II (RNAPII) phosphorylation at serine 2. Functional consequences of the inhibition of transcriptional activity of ERα and AR by HEXIM1 include the inhibition of ERα- and AR-dependent gene expression, respectively, and the resulting attenuation of breast cancer (BCa) and prostate cancer (PCa) cell proliferation and growth. In our present study, we determined that HEXIM1 inhibited AKR1C3 expression in BCa and PCa cells. AKR1C3, also known as 17ß-hydroxysteroid dehydrogenase (17ß-HSD) type 5, is a key enzyme involved in the synthesis of 17ß-estradiol (E2) and 5-dihydrotestosterone (DHT). Downregulation of AKR1C3 by HEXIM1 influenced E2 and DHT production, estrogen- and androgen-dependent gene expression, and cell proliferation. Our studies indicate that HEXIM1 has the unique ability to inhibit both the transcriptional activity of the ER and AR and the synthesis of the endogenous ligands of these receptors.

Citrate Association Dramatically Reduces Diameter with Concomitant Increase in Uptake of Drug-Loaded Carbonate Apatite Particles in Breast Cancer Cells.

Inorganic nanoparticles are commonly employed as vectors for delivering drugs into cancer cells while decreasing undesired cytotoxicity in healthy tissues. Carbonate apatite is an attractive nonviral vector that releases drugs at acidic environment inside the cells following endocytosis. However, maintaining the smaller particle size is crucial for enhancing cellular uptake of drugs as well as prolonging their systemic circulation time. We aimed to modify carbonate apatite with citrate for reducing the growth kinetics of carbonate apatite particles and enhancing the cellular uptake of cyclophosphamide via endocytosis. Several concentrations of sodium citrate were used to fabricate citrate-modified carbonate apatite (CMCA) particle complexes in absence or presence of cyclophosphamide. The binding affinity of the drug towards the particles and its cellular uptake were measured by high-performance liquid chromatography (HPLC). The nanoparticles' average size and zeta potential were determined by Malvern Zetasizer. Fourier-transform infrared spectroscopy (FTIR) was performed to justify association of citrate with carbonate apatite. MTT assay was performed to evaluate the cell viability. CMCA exhibited 6% more binding efficiency for cyclophosphamide and promoted fast cellular uptake of cyclophosphamide with enhanced cytotoxicity in MCF-7 cells, compared to unmodified carbonate apatite. Therefore, CMCA nanoparticles have a high potential for intracellular delivery of anti-cancer drugs and demand for further investigated in animal models of cancer.

Impact of PEGylated Nanoparticles on Tumor Targeted Drug Delivery.

PEG-functionalized nanoparticles as carriers of chemotherapeutics agents have been explored with notable successes in preclinical and clinical stages of cancer treatment, with some already approved by FDA, namely PEGylated liposomes and polymers. Half-life extension of therapeutic agents through PEGylation process improves their pharmacokinetic (PK) profiles, thereby reducing their dosing frequency. Protein corona composition of PEGylated nanoparticles (NPs) confers a tremendous influence on their surface characteristics which directly impact tumor accumulation and clearance properties of the drugs. By controlling the size and complexity of PEG molecules, as well as by attaching targeting moieties, the surface characteristics of NPs can be manipulated to improve their tumor uptake without sacrificing the circulation time. This review focuses on design and applications of PEGylated NPs for tumor targeted drug delivery in animal models and clinical setting.

PEGylation of Carbonate Apatite Nanoparticles Prevents Opsonin Binding and Enhances Tumor Accumulation of Gemcitabine.

pH sensitives carbonate apatite (CA) has emerged as a targeted delivery vehicle for chemotherapeutics agent with tremendous potential to increase the effectivity of breast cancer treatment. The major challenge for intravenous delivery of drug-incorporated nanoparticles is their rapid opsonization, resulting in accumulation within the organs of reticuloendothelial system, such as liver and spleen. Therefore, surface modification by polyethylene glycol was implemented to improve the half-life of drug-particle complexes and enhance their uptake by target tissues. A simple, rapid, and sensitive triple quadrupole liquid chromatography-mass spectrometry method was developed and validated for quantification of gemcitabine in plasma, various organs and tumor tissues of mice with breast carcinoma, whereas sodium dodecyl sulfate-polyacrylamide gel electrophoresis, quadrupole-time of flight liquid chromatography-mass spectrometry and analysis by SwissProt.Mus_musculus database were performed for protein separation, identification, and homology search by comparing the de novo sequence tag. PEGylated CA exhibited almost 6-fold increase in gemcitabine accumulation in tumor with significant reduction in other organs within 1 h of intravenous administration, compared to free drug. In addition, plasma drug amount was found to be higher in PEGylated particles, implying their role in prolonging blood circulation time of particle-bound gemcitabine. Investigation of protein corona composition demonstrated notable reduction in opsonin interactions after PEGylation of CA particles. Overall, the results indicate that the composition and dynamics of protein corona subjected to alteration by PEGylation play crucial roles in affecting successful nanoparticle-based targeted delivery of a cytotoxic drug.

Surface-Modification of Carbonate Apatite Nanoparticles Enhances Delivery and Cytotoxicity of Gemcitabine and Anastrozole in Breast Cancer Cells.

pH sensitive nanoparticles of carbonate apatite (CA) have been proven to be effective delivery vehicles for DNA, siRNAs and proteins. More recently, conventional anti-cancer drugs, such as doxorubicin, methotrexate and cyclophosphamide have been successfully incorporated into CA for intracellular delivery to breast cancer cells. However, physical and chemical properties of drug molecules appeared to affect their interactions with CA, with hydrophillic drug so far exhibiting better binding affinity and cellular uptakes compared to hydrophobic drugs. In this study, anastrozole, a non-steroidal aromatase inhibitor which is largely hydrophobic, and gemcitabine, a hydrophilic nucleoside inhibitor were used as solubility models of chemotherapy drug. Aggregation tendency of poorly soluble drugs resulting in larger particle-drug complex size might be the main factor hindering their delivery effectiveness. For the first time, surface modification of CA with poly(ethylene glycol) (PEG) has shown promising result to drastically reduce anastrozole- loaded CA particle size, from approximately 1000 to 500 nm based on zeta sizer analysis. Besides PEG, a cell specific ligand, in this case fibronectin, was attached to the particles in order to facilitate receptor mediated endocytosis based on fibronectin-integrin interaction. High-performance liquid chromatography (HPLC) was performed to measure uptake of the drugs by breast cancer cells, revealing that surface modification increased the drug uptake, especially for the hydrophobic drug, compared to the uncoated particles and the free drug. In vitro chemosensitivity assay and in vivo tumor regression study also showed that coated apatite/drug nanoparticle complexes presented higher cytotoxicity and tumor regression effects than uncoated apatite/drug nanoparticles and free drugs, indicating that surface modification successfully created optimum particles size with the consequence of more effective uptake along with favorable pharmacokinetics of the particles.

Gemcitabine interacts with carbonate apatite with concomitant reduction in particle diameter and enhancement of cytotoxicity in breast cancer cells.

Substantial amount of research has been done in recent decades for the development of nanoparticle systems to selectively deliver drugs to cancer cells for concurrently enhancing and reducing anti-cancer and off-target effects, respectively. pH-sensitive carbonate apatite (CA) was originally developed for efficient and targeted delivery of DNA, siRNA and proteins to various cancer cell lines. Recently, the CA particles were employed to deliver anti-cancer drugs, cyclophosphamide, doxorubicin and methotrexate to cancer cells. Here, we report on the fabrication and characterization of gemcitabine- loaded CA particles, followed by the evaluation of their roles in enhancement of cytotoxicity in two human and one murine breast cancer cell lines. HPLC was performed to measure binding efficiency of the drug to the apatite particles whereas particle size and zeta potential were evaluated to characterize drug/apatite complex. Depending on the initial doses of the drug, its bind binding affinity towards the particles varied from 3.85% to 4.45%. The particle size was found to surprisingly decrease with an increase of the initial drug concentration. In vitro chemosensitivity assay revealed that apatite/drug nanoparticle complexes presented significantly higher cytotoxicity to breast cancer cells compared to free drugs, which could be correlated with the enhanced cellular uptake of the small size drug-loaded particles through endocytosis compared to the passive diffusion of the free drug.