Short-term, increasing dietary protein and fat moderately affect energy expenditure, substrate oxidation and uncoupling protein gene expression in rats

Macronutrient composition of diets can influence body-weight development and energy balance. We studied the short-term effects of high-protein (HP) and/or high-fat (HF) diets on energy expenditure (EE) and uncoupling protein (UCP1-3) gene expression. Adult male rats were fed ad libitum with diets containing different protein-fat ratios: adequate protein-normal fat (AP-NF): 20% casein, 5% fat; adequate protein-high fat (AP-HF): 20% casein, 17% fat; high protein-normal fat (HP-NF): 60% casein, 5% fat; high protein-high fat (HP-HF): 60% casein, 17% fat. Wheat starch was used for adjustment of energy content. After 4 days, overnight EE and oxygen consumption, as measured by indirect calorimetry, were higher and body-weight gain was lower in rats fed with HP diets as compared with rats fed diets with adequate protein content (P<.05). Exchanging carbohydrates by protein increased fat oxidation in HF diet fed groups. The UCP1 mRNA expression in brown adipose tissue was not significantly different in HP diet fed groups as compared with AP diet fed groups. Expression of different homologues of UCPs positively correlated with nighttime oxygen consumption and EE. Moreover, dietary protein and fat distinctly influenced liver UCP2 and skeletal muscle UCP3 mRNA expressions. These findings demonstrated that a 4-day ad libitum high dietary protein exposure influences energy balance in rats. A function of UCPs in energy balance and dissipating food energy was suggested. Future experiments are focused on the regulation of UCP gene expression by dietary protein, which could be important for body-weight management.     

Pigment epithelium-derived factor expression prolongs survival and enhances the cytotoxicity of low-dose chemotherapy in castration-refractory prostate cancer

There is currently no cure for advanced castration-refractory prostate cancer (CRPC) despite the recent approval of several new therapeutic agents. We report here the anti-tumor effect of the angio-inhibitory pigment epithelium-derived factor (PEDF) in the metastatic LNCaP-derivative CRPC CL1 model and explore PEDF anti-neoplasic efficacy in combination with low-dose chemotherapy. Androgen-sensitive LNCaP and CRPC PC3 cell lines were examined as comparison. Using a retroviral expression system, we showed that PEDF limited the proliferation of all prostatic cell lines tested; an effect attributed to interleukin 8 (IL8)-CXCR1/IL8RA inhibition. PEDF also reduced the number and size of 3D tumor spheroids in vitro, but only induced cell differentiation in CRPC spheroids. Similarly, PEDF inhibited the migration of CRPC cells suggesting both anti-proliferative and anti-migratory functions. In vivo, PEDF decreased by 85% and 65% the growth of subcutaneous (s.c.) PC3 and CL1 tumors, respectively. In the CL1 orthotopic model, tumor intake with lethal metastases was found in all animals; nevertheless, PEDF prolonged the median survival of tumor-bearing mice (95% confidence interval: 53±0.001 to 57±1 days). Accordingly, PEDF delayed the emergence of skeletal-related event in intra-tibial xenografts. Next, we evaluated low-dose docetaxel (DTX; 5, 1, 0.5 mg/kg) or cyclophosphamide (CTX; 10–20 mg/kg) on established s.c. PC3 tumors that conditionally express PEDF anti-tumoral epitope/NT3. Although NT3–DTX-5 mg/kg combination was inefficient, NT3–DTX-1 mg/kg and -0.5 mg/kg inhibited by 95% and 87.8%, respectively, tumor growth compared with control and induced tumor stasis. Both NT3–CTX combinations were advantageous. Inversely, PEDF–DTX-5 mg/kg and PEDF–CTX-10 mg/kg delayed the most CL1 tumor growth (15, 11 and 5 days for PEDF–DTX-5 mg/kg, PEDF–CTX-10 mg/kg and single treatments, respectively) with elevated apoptosis and serum thrombospondin-1 as possible mechanism and marker, respectively. As well, both PEDF–CTX-10 mg/kg and PEDF–DTX-5 mg/kg prolonged significantly the survival of tumor-bearing mice compared with single treatments. Metastases were reduced in PEDF–DTX-5 mg/kg compared with other treatments, suggesting that PEDF–DTX delayed metastases formation. Our results advocate that PEDF/low-dose chemotherapy may represent a new therapeutic alternative for CRPC.     

Characterization of PEDF: A multi‐functional serpin family protein

Pigment epithelium‐derived factor (PEDF) is a 50 kDa secreted glycoprotein that belongs to the non‐inhibitory serpin family group. PEDF has been described as a natural angiogenesis inhibitor with neurotrophic and immune‐modulation properties; it balances angiogenesis in the eye and blocks tumor progression. The mechanisms underlying most of these events are not completely clear; however, it appears that PEDF acts via multiple high affinity ligands and cell receptors. In this review article, we will summarize the current knowledge on the biochemical properties of PEDF and its receptors, the multimodal activities of PEDF and finally address the therapeutic potential of PEDF in treating angiogenesis‐, neurodegeneration‐ and inflammation‐related diseases. J. Cell. Biochem. 106: 769–775, 2009. © 2009 Wiley‐Liss, Inc.     

Auto-ADP-ribosylation of Pseudomonas aeruginosa ExoS

Pseudomonas aeruginosa Exoenzyme S (ExoS) is a bifunctional type-III cytotoxin. The N terminus possesses a Rho GTPase-activating protein (GAP) activity, whereas the C terminus comprises an ADP-ribosyltransferase domain. We investigated whether the ADP-ribosyltransferase activity of ExoS influences its GAP activity. Although the ADP-ribosyltransferase activity of ExoS is dependent upon FAS, a 14-3-3 family protein, factor-activating ExoS (FAS) had no influence on the activity of the GAP domain of ExoS (ExoS-GAP). In the presence of NAD and FAS, the GAP activity of full-length ExoS was reduced about 10-fold, whereas NAD and FAS did not affect the activity of the ExoS-GAP fragment. Using [(32)P]NAD, ExoS-GAP was identified as a substrate of the ADP-ribosyltransferase activity of ExoS. Site-directed mutagenesis revealed that auto-ADP-ribosylation of Arg-146 of ExoS was crucial for inhibition of GAP activity in vitro. To reveal the auto-ADP-ribosylation of ExoS in intact cells, tetanolysin was used to produce pores in the plasma membrane of Chinese hamster ovary (CHO) cells to allow the intracellular entry of [(32)P]NAD, the substrate for ADP-ribosylation. After a 3-h infection of CHO cells with Pseudomonas aeruginosa, proteins of 50 and 25 kDa were preferentially ADP-ribosylated. The 50-kDa protein was determined to be auto-ADP-ribosylated ExoS, whereas the 25-kDa protein appeared to represent a group of proteins that included Ras.     

Subcutaneous interleukin-2 and interferon-alpha 2b in patients with metastatic renal cell cancer: the German outpatient experience

A phase II clinical trial was conducted using subcutaneous recombinant human interleukin-2 (rIL-2, EuroCetus) and subcutaneous interferon-alpha 2b (rIFN-alpha 2b, Essex) in patients with advanced cancer. Safety and tolerance of this outpatient regimen were assessed in 17 patients with progressive metastatic renal carcinoma, 14 of whom were evaluable for clinical response to combined rIL-2 and rIFN-alpha 2b. In this study, rIL-2 was administered every 12 hours, at 1.5 million (Cetus) U/m2 on days 1 and 2, followed by 0.3 million U/m2 5 days per week for 6 consecutive weeks. Concomitantly, rIFN-alpha 2b was given as 5 million U/m2 three times weekly for 6 consecutive weeks. Patients presenting with stable or regressive disease after 6 weeks of rIL-2 and rIFN-alpha 2b (11 of 14) were scheduled to repeat combination therapy. After one treatment cycle, five of 14 patients presented with partial remission; two of these patients achieved complete regression of metastatic lesions. After therapy, six patients have been in stable disease for up to 8 months. toxicity of this regimen was moderate, with local inflammation of the injection sites, grade I-II (World Health Organization criteria) fevers, chills, malaise, nausea and/or vomiting, and anorexia in 70% to 100% of patients treated. After 6 weeks of rIL-2 and rIFN-alpha 2b, laboratory evidence of treatment-related hypothyroidism and hyperthyroidism was obtained in one and four patients, respectively. Immunogenicity of sc rIL-2 was mostly limited to the development of nonneutralizing antibodies that occurred in approximately 40% of patients. None of the patients exhibited antibodies specific to rIFN-alpha 2b.     

Predicting infant temperament from neonatal reactivity for AGA/SGA twin pairs.

The predictive relation between neonatal reactivity and 12-, 18-, and 24-month temperament was assessed for 22 appropriate-for-gestational-age (AGA)/small-for-gestational-age (SGA) twin pairs. Neonatal reactivity included ratings of visual and auditory orienting responses to a bull's-eye, rattle, bell, voice, and face plus voice combined, as well as alertness. Infant temperament ratings were made of emotional tone, activity, attentiveness, and social orientation to staff during age-appropriate activities in the laboratory. There were no group differences in the neonatal or infant ratings. For AGA twins, a pattern of predictive correlations was obtained between neonatal reactivity and temperament at each age. A similar predictive pattern was not observed for the SGA twins. Group differences in rates of maturation related to stresses associated with intrauterine growth retardation influenced the significance of the neonatal variables for later temperament development.