Linker Optimization and Therapeutic Evaluation of Phosphatidylserine-Targeting Zinc Dipicolylamine-based Drug Conjugates.

We report that compound 13, a novel phosphatidylserine-targeting zinc(II) dipicolylamine drug conjugate, readily triggers a positive feedback therapeutic loop through the in situ generation of phosphatidylserine in the tumor microenvironment. Linker modifications, pharmacokinetics profiling, in vivo antitumor studies, and micro-Western array of treated-tumor tissues were employed to show that this class of conjugates induced regeneration of apoptotic signals, which facilitated subsequent recruitment of the circulating conjugates through the zinc(II) dipicolylamine-phosphatidylserine association and resulted in compounding antitumor efficacy. Compared to the marketed compound 17, compound 13 not only induced regressions in colorectal and pancreatic tumor models, it also exhibited at least 5-fold enhancement in antitumor efficacy with only 40% of the drug employed during treatment, culminating in a >12.5-fold increase in therapeutic potential. Our study discloses a chemically distinct apoptosis-targeting theranostic, with built-in complementary functional moieties between the targeting module and the drug mechanism to expand the arsenal of antitumor therapy.

Lipid Emulsion Added to a Liquid High-Carbohydrate Diet and Voluntary Running Exercise Reduce Lipogenesis and Ameliorate Early-Stage Hepatic Steatosis in Mice.

Background: The use of parenteral nutrition formulas is often associated with the development of hepatic steatosis. We have shown previously that the addition of a lipid emulsion (LE) rich in n-6 (ω-6) fatty acids (FAs) ameliorated triglyceride (TG) accumulation in the livers of nonobese mice fed a high-carbohydrate diet (HCD) for 5 wk. However, it remains unclear how rapidly this condition develops and whether it can be prevented by LE with or without a running wheel for voluntary exercise (Exe).Objective: We investigated in an 8-d study whether mice develop steatosis and whether the administration of LE with or without Exe reduces the concentration of total FAs and prevents an increase in the expression of genes in the liver associated with lipogenesis.Methods: Male C57BL/6 mice aged 5 wk were randomized into 5 groups: standard feed pellet (SFP); a liquid HCD (77% of total energy from carbohydrates and 0.5% from fat); HCD + Exe; HCD + 13.5% LE (67% carbohydrates and 13.5% fat); or HCD + 13.5% LE + Exe. Hepatic TG concentration, lipogenic genes, and total FAs were measured on day 8.Results: Oil Red O staining and TG quantification showed hepatic TG accumulation on day 8; the addition of 13.5% LE either with or without Exe suppressed the TG accumulation compared with HCD (P < 0.005). With the use of quantitative reverse transcriptase-polymerase chain reaction analysis, the expression concentrations of lipogenic genes [ATP-citrate lyase, acetyl coenzyme A carboxylase 1, FA synthase (Fasn), and stearoyl coenzyme A desaturase 1 (Scd1)] in the HCD + 13.5% LE group were 26-60% of HCD (P < 0.01) and 11-38% of HCD in the HCD + 13.5% LE + Exe group (P < 0.001), with interactions for Fasn and Scd1 (P < 0.05). With the use of gas chromatography-mass spectrometry analysis, the HCD + 13.5% LE group had lower monounsaturated fatty acids (38.7% of HCD) but higher polyunsaturated fatty acids (164% of HCD) (P < 0.001).Conclusions: In short-term studies designed to resemble the early dynamic stage of the development of hepatic steatosis, the addition of 13.5% LE to a liquid HCD reduced hepatic lipogenesis. Exe exerted an independent protective effect and interacted with LE to further reduce the expression of Scd1.

Effects of glutamine administration on inflammatory responses in chronic ethanol-fed rats.

The purpose of this study was to investigate the effects of glutamine supplementation on inflammatory responses in chronic ethanol-fed rats. Male Wistar rats weighing about 160 g were divided into five groups. Two groups were fed a normal liquid diet and three groups were fed a glutamine-containing liquid diet. After 1 week, one of the normal liquid diet groups was fed an ethanol-containing liquid diet (CE), and the other group served as the control (CC) group. At the same time, one of the glutamine-containing liquid diet groups was continually fed the same diet (GCG), but the other two groups were fed ethanol-containing diet supplemented with glutamine (GEG) or without glutamine (GE). The following items were analyzed: (1) liver function, (2) cytokine contents, and (3) hepatic oxidative stress. The activities of aspartate transaminase (AST) and alanine transaminase (ALT) and levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß in the CE group had significantly increased. In addition, hepatic cytochrome P450 2E1 (CYP2E1) expression had significantly increased in the CE, GE and GEG groups. However, the activities of AST and ALT and levels of TNF-α and IL-1ß in the GE group were significantly lower than those of the CE group. The results suggest that the plasma inflammatory responses of rats fed an ethanol-containing liquid diet for 7 weeks significantly increased. However, pretreatment with glutamine improved the plasma inflammatory responses induced by ethanol.

Effects of dietary arginine on inflammatory mediator and receptor of advanced glycation endproducts (RAGE) expression in rats with streptozotocin-induced type 2 diabetes.

Arginine (Arg) is known to possess numerous useful physiological properties and have immunomodulatory effects. In vitro studies reported that Arg inhibits advanced glycation endproduct (AGE) formation; however, the effects of Arg on the receptor of AGE (RAGE) expression in inflammatory conditions are not clear. The present study investigated the effects of dietary Arg supplementation on inflammatory mediator production and RAGE expression in type 2 diabetic rats. There were one normal control (NC) group and two diabetic groups in the present study. Rats in the NC group were fed with a regular chow diet. One diabetic group (DM) was fed a common semi-purified diet while the other diabetic group received a diet in which part of the casein was replaced by Arg (DM-Arg) for 8 weeks. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 1800 mg/l were considered diabetic. Blood samples and the liver and lungs of the animals were collected at the end of the study for further analysis. Results showed that plasma glucose and fructosamine contents were significantly higher in the diabetic groups than those in the NC group. The DM group had higher fructosamine and C-reactive protein than the DM-Arg group. Immunohistochemical staining showed that the expressions of RAGE in liver and lung tissues were significantly lower in the DM-Arg group than in the DM group. These results suggest that supplemental dietary Arg can decrease AGE-RAGE interactions and consequently reduce tissue damage in rats with type 2 diabetes.