Synthesis and antitumor efficacy of daunorubicin-loaded magnetic nanoparticles

Jun Wang1, Baoan Chen1, Jian Chen1, Xiaohui Cai1, Guohua Xia2, Ran Liu1, Pingsheng Chen2, Yu Zhang3, Xuemei Wang31Department of Hematology and Oncology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China 210009; 2Medical School, Southeast University, Nanjing; 3State Key Laboratory of Bioelectronics, Southeast University, Nanjing, China 210009Background: A promising approach to optimize the disposition of daunorubicin-loaded magnetic nanoparticles (DNR-MNPs) was developed to minimize serious side effects of systematic chemotherapy for cancer.Methods: The physical properties of DNR-MNPs were investigated and their effect on leukemia cells in vitro was evaluated by a standard WST-1 cell proliferation assay. Furthermore, cell apoptosis and intracellular accumulation of DNR were determined by FACSCalibur flow cytometry.Results: Our results showed that the majority of MNPs were spherical and their sizes were from 10 to 20 nm. The average hydrodynamic diameter of DNR-MNPs in water was 94 nm. The in vitro release data showed that the DNR-MNPs have excellent sustained release property. Proliferation of K562 cells was inhibited in a dose-dependent manner by DNR in solution (DNR-Sol) or by DNR-MNPs. The IC50 for DNR-MNPs was slightly higher than that for DNR-Sol. DNR-MNPs also induced less apoptosis in K562 cells than did DNR-Sol. Detection of fluorescence intensity of intracellular DNR demonstrated that DNR-MNPs could be taken up by K562 cells and persistently released DNR in cells.Conclusion: Our study suggests that optimized DNR-MNPs formulation possesses sustained drug-release and favorable antitumor properties, which may be used as a conventional dosage form for antitumor therapy.Keywords: daunorubicin, magnetic iron oxide nanoparticles, drug delivery system, target selection, K562 cell

Identification of lipid droplet structure-like/resident proteins in Caenorhabditis elegans.

The lipid droplet (LD) is a cellular organelle that stores neutral lipids in cells and has been linked with metabolic disorders. Caenorhabditis elegans has many characteristics which make it an excellent animal model for studying LDs. However, unlike in mammalian cells, no LD structure-like/resident proteins have been identified in C. elegans, which has limited the utility of this model for the study of lipid storage and metabolism. Herein based on three lines of evidence, we identified that MDT-28 and DHS-3 previously identified in C. elegans LD proteome were two LD structure-like/resident proteins. First, MDT-28 and DHS-3 were found to be the two most abundant LD proteins in the worm. Second, the proteins were specifically localized to LDs and we identified the domains responsible for this targeting in both proteins. Third and most importantly, the depletion of MDT-28 induced LD clustering while DHS-3 deletion reduced triacylglycerol content (TAG). We further characterized the proteins finding that MDT-28 was ubiquitously expressed in the intestine, muscle, hypodermis, and embryos, whereas DHS-3 was expressed mainly in intestinal cells. Together, these two LD structure-like/resident proteins provide a basis for future mechanistic studies into the dynamics and functions of LDs in C. elegans

Tracing evolutionary footprints to identify novel gene functional linkages.

Systematic determination of gene function is an essential step in fully understanding the precise contribution of each gene for the proper execution of molecular functions in the cell. Gene functional linkage is defined as to describe the relationship of a group of genes with similar functions. With thousands of genomes sequenced, there arises a great opportunity to utilize gene evolutionary information to identify gene functional linkages. To this end, we established a computational method (called TRACE) to trace gene footprints through a gene functional network constructed from 341 prokaryotic genomes. TRACE performance was validated and successfully tested to predict enzyme functions as well as components of pathway. A so far undescribed chromosome partitioning-like protein ro03654 of an oleaginous bacteria Rhodococcus sp. RHA1 (RHA1) was predicted and verified experimentally with its deletion mutant showing growth inhibition compared to RHA1 wild type. In addition, four proteins were predicted to act as prokaryotic SNARE-like proteins, and two of them were shown to be localized at the plasma membrane. Thus, we believe that TRACE is an effective new method to infer prokaryotic gene functional linkages by tracing evolutionary events

ORP4L Extracts and Presents PIP2 from Plasma Membrane for PLC beta 3 Catalysis : Targeting It Eradicates Leukemia Stem Cells

Leukemia stem cells (LSCs) are a rare subpopulation of abnormal hematopoietic stem cells (HSCs) that propagates leukemia and are responsible for the high frequency of relapse in therapies. Detailed insights into LSCs' survival will facilitate the identification of targets for therapeutic approaches. Here, we develop an inhibitor, LYZ-81, which targets ORP4L with high affinity and specificity and selectively eradicates LCSs in vitro and in vivo. ORP4L is expressed in LSCs but not in normal HSCs and is essential for LSC bioenergetics and survival. It extracts PIP2 from the plasma membrane and presents it to PLC beta 3, enabling IP3 generation and subsequentCa(2+)-dependent bioenergetics. LYZ-81 binds ORP4L competitively with PIP2 and blocks PIP2 hydrolysis, resulting in defective Ca2+ signaling. The results provide evidence that LSCs can be eradicated through the inhibition of ORP4L by LYZ-81, which may serve as a starting point of drug development for the elimination of LSCs to eventually cure leukemia.Peer reviewe

Reactive Oxygen Species Released from Hypoxic Hepatocytes Regulates MMP-2 Expression in Hepatic Stellate Cells

Hypoxia is a common environmental stress factor and is associated with fibrogenesis. Matrix metalloproteinase-2 (MMP-2), produced by hepatic stellate cells (HSCs), plays an important role in liver fibrogenesis. However, inconsistent results have been reported on the impact of hypoxia on MMP-2 expression and activity in HSCs. We speculated that cell–cell interaction is involved in the regulation of MMP-2 expression and activity at low oxygen level in vivo. Therefore, in this report we investigated the mechanism by which hypoxic hepatocytes regulates MMP-2 expression in HSCs. Our results showed that the conditioned medium from hypoxia-treated rat hepatocytes strongly induced the expression of MMP-2 mRNA and protein in rat HSC-T6 cells. Reduced glutathione neutralized ROS released from hypoxic hepatocytes, leading to reduced MMP-2 expression in HSC-T6 cells. In addition, phospho-IκB-α protein level was increased in HSC-T6 cells treated with hypoxia conditioned medium, and NF-κB signaling inhibitor inhibited MMP-2 expression in HSC-T6 cells. Taken together, our data suggest that ROS is an important factor released by hypoxic hepatocytes to regulate MMP-2 expression in HSCs, and NF-κB signaling is crucially involved in ROS-induced MMP-2 expression in HSCs. Our findings suggest that strategies aimed at antagonizing the generation of ROS in hypoxic hepatocytes and inhibiting NF-κB signaling in HSCs may represent novel therapeutic options for liver fibrosis

The proteomics of lipid droplets: structure, dynamics, and functions of the organelle conserved from bacteria to humans.

Lipid droplets are cellular organelles that consists of a neutral lipid core covered by a monolayer of phospholipids and many proteins. They are thought to function in the storage, transport, and metabolism of lipids, in signaling, and as a specialized microenvironment for metabolism in most types of cells from prokaryotic to eukaryotic organisms. Lipid droplets have received a lot of attention in the last 10 years as they are linked to the progression of many metabolic diseases and hold great potential for the development of neutral lipid-derived products, such as biofuels, food supplements, hormones, and medicines. Proteomic analysis of lipid droplets has yielded a comprehensive catalog of lipid droplet proteins, shedding light on the function of this organelle and providing evidence that its function is conserved from bacteria to man. This review summarizes many of the proteomic studies on lipid droplets from a wide range of organisms, providing an evolutionary perspective on this organelle

Clinical Evaluation of Targeted Arterial Infusion of Verapamil in the Interventional Chemotherapy of Primary Hepatocellular Carcinoma

This study evaluates the clinical effectiveness of targeted arterial infusion of verapamil in interventional treatment of primary hepatocellular carcinoma. For this purpose, in 273 patients with middle- or late-stage primary hepatocellular carcinoma, verapamil, IL-2, and chemotherapeutic agents were infused into the target tumor vasculature through femoral artery using Seldinger technique. The medications were infused as serial dilutions, and effectiveness was evaluated after two treatment cycles. Among these 273 patients, 76 cases showed clinical cure or significant improvement, 119 cases improved, 64 cases stabilized, while 14 cases progressed or deteriorated. In 238 patients, KPS score and body weights were stabilized. Regarding side effects, 99 patients (36.3%) developed leukopenia; 160 patients had gastrointestinal reactions (58.6%); 80 patients (29.3%) presented with elevated ALT/AST profile; and 65 cases (23.8%) had pyrexia; however, these side effects abated quickly. No elevations in BUN/Cr and/or allergic reactions were observed. Pre- and post-intervention cardiac function did not change in all the patients. No significant change was observed in ECG. Liver function was also improved after two cycles of treatment. It was concluded that verapamil management via targeted arterial infusion could effectively reverse the multidrug resistance in cancer cells in primary hepatocellular carcinoma patients and therefore enhanced the efficacy of chemotherapy

Targeted therapy of liver fibrosis on the horizon

Over the past few years, significant advances have occurred in the targeted therapy of liver fibrosis. However, it is still a big challenge to deliver drugs to target cells and exert desirable therapeutic effect. The research on targeted therapy of liver fibrosis, including the types of target cells and target molecules and their selection rules, the general rules and methods for carrier selection and modification, and the evaluation of treatment outcomes and toxic or side effects, is reviewed. It is pointed out that liver fibrosis is a complex pathological process involving multiple cells, cytokines, and signaling pathways, so selecting suitable therapeutic target is the key to targeted therapy, and proper development of targeted delivery system is the guarantee for successful treatment