Creation of an Anti-Inflammatory, Leptin-Dependent Anti-Obesity Celastrol Mimic with Better Druggability.

Obesity is characterized by an excessive body mass, but is also closely associated with metabolic syndrome. And, so far, only limited pharmacological treatments are available for obesity management. Celastrol, a pentacyclic triterpenoid from a traditional Chinese medicine (Tripterygium wilfordii Hook.f.), has shown remarkable potency against obesity, inflammation and cancer, but its high toxicity, low natural abundance and tedious chemical synthesis hindered its translation into clinics. In the present work, a triterpenoid library was screened for compounds with both high natural abundance and structural similarity to celastrol; from this library, glycyrrhetinic acid (GA), a compound present in extremely high yields in Glycyrrhiza uralensis Fisch. ex DC., was selected as a possible scaffold for a celastrol mimic active against obesity. A simple chemical modification of GA resulted in GA-02, a derivative that suppressed 68% of food intake in diet-induced obesity mice and led to 26.4% weight loss in 2 weeks. GA-02 plays a role in obesity treatment by re-activating leptin signaling and reducing systemic and, more importantly, hypothalamic inflammation. GA-02 was readily bioavailable with unnoticeable in vitro and in vivo toxicities. The strategy of scaffold search and modification on the basis of bio-content and structural similarity has proved to be a green, economic, efficient and practical way of widening the medicinal applications of "imperfect" bioactive natural compounds.

Validation of MRI quantitative susceptibility mapping of superparamagnetic iron oxide nanoparticles for hyperthermia applications in live subjects.

The use of magnetic fluid hyperthermia (MFH) for cancer therapy has shown promise but lacks suitable methods for quantifying exogenous irons such as superparamagnetic iron oxide (SPIO) nanoparticles as a source of heat generation under an alternating magnetic field (AMF). Application of quantitative susceptibility mapping (QSM) technique to prediction of SPIO in preclinical models has been challenging due to a large variation of susceptibility values, chemical shift from tissue fat, and noisier data arising from the higher resolution required to visualize the anatomy of small animals. In this study, we developed a robust QSM for the SPIO ferumoxytol in live mice to examine its potential application in MFH for cancer therapy. We demonstrated that QSM was able to simultaneously detect high level ferumoxytol accumulation in the liver and low level localization near the periphery of tumors. Detection of ferumoxytol distribution in the body by QSM, however, required imaging prior to and post ferumoxytol injection to discriminate exogenous iron susceptibility from other endogenous sources. Intratumoral injection of ferumoxytol combined with AMF produced a ferumoxytol-dose dependent tumor killing. Histology of tumor sections corroborated QSM visualization of ferumoxytol distribution near the tumor periphery, and confirmed the spatial correlation of cell death with ferumoxytol distribution. Due to the dissipation of SPIOs from the injection site, quantitative mapping of SPIO distribution will aid in estimating a change in temperature in tissues, thereby maximizing MFH effects on tumors and minimizing side-effects by avoiding unwanted tissue heating.

Thyroid stimulating hormone increases iodine uptake by thyroid cancer cells during BRAF silencing.

BACKGROUND: The BRAF(V600E) mutation is present in 62% of radioactive iodine-resistant thyroid tumors and is associated with downregulation of the sodium-iodide symporter (NIS) and thyroid stimulating hormone receptor (TSHr). We sought to evaluate the combined effect of BRAF inhibition and TSH supplementation on (131)I uptake of BRAF(V600E)-mutant human thyroid cancer cells. MATERIALS AND METHODS: WRO cells (a BRAF(V600E)-mutant follicular-derived papillary thyroid carcinoma cell line) were transfected with small interfering RNA targeting BRAF for 72 h in a physiological TSH environment. NIS and TSHr expression were then evaluated at three levels: gene expression, protein levels, and (131)I uptake. These three main outcomes were then reassessed in TSH-depleted media and media supplemented with supratherapeutic concentrations of TSH. RESULTS: NIS gene expression increased 5.5-fold 36 h after transfection (P = 0.01), and TSHr gene expression increased 2.8-fold at 24 h (P = 0.02). NIS and TSHr protein levels were similarly increased 48 and 24 h after transfection, respectively. Seventy-two hours after BRAF inhibition, (131)I uptake was unchanged in TSH-depleted media, increased by 7.5-fold (P < 0.01) in physiological TSH media, and increased by 9.1-fold (P < 0.01) in supratherapeutic TSH media. CONCLUSIONS: The combined strategy of BRAF inhibition and TSH supplementation results in greater (131)I uptake than when either technique is used alone. This represents a simple and feasible approach that may improve outcomes in patients with radioactive iodine-resistant thyroid carcinomas for which current treatment algorithms are ineffective.