Inhibition of cytohesin-1 by siRNA leads to reduced IGFR signaling in prostate cancer

To explore how cytohesin-1 (CYTH-1) small interfering RNA (siRNA) influences the insulin-like growth factor receptor (IGFR)-associated signal transduction in prostate cancer, we transfected human prostate cancer PC-3 cell lines with liposome-encapsulatedCYTH-1 siRNA in serum-free medium and exposed the cells to 100 nM IGF-1. The mRNA and protein levels of the signal molecules involved in the IGFR signaling pathways were determined by real-time PCR and detected by Western blotting. The relative mRNA levels of CYTH-1, c-Myc, cyclinD1 and IGF-1R (CYTH-1 siRNA group vs scrambled siRNA group) were 0.26 vs 0.97, 0.34 vs 1.06, 0.10 vs 0.95, and 0.27 vs 0.41 (P < 0.05 for all), respectively. The relative protein levels of CYTH-1, pIGF-1R, pIRS1, pAkt1, pErk1, c-Myc, and cyclinD1 (CYTH-1 siRNA group vsscrambled siRNA group) were 0.10 vs 1.00 (30 min), 0.10 vs 0.98 (30 min), 0.04 vs 0.50 (30 min), 0.10 vs 1.00 (30 min), 0.10 vs 1.00 (30 min), 0.13 vs 0.85 (5 h), and 0.08 vs 0.80 (7 h), respectively. The tyrosine kinase activity of IGF-1R was associated with CYTH-1. The proliferative activity of PC-3 cells transfected with CYTH-1 siRNA was significantly lower than that of cells transfected with scrambled siRNA at 48 h (40.5 vs87.6%, P < 0.05) and at 72 h (34.5 vs 93.5%, P < 0.05). In conclusion, the interference of siRNA with cytohesin-1 leads to reduced IGFR signaling in prostate cancer; therefore, CYTH-1 might serve as a new molecular target for the treatment of prostate cancer.

Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT1 receptor (AT1-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO2 = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT1-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT1-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT1-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT1-R staining, but C animals showed weak iNOS and AT1-R staining. Macrophages of L and P animals showed moderate and weak AT2-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT1-R blockade. We suggest that AT1-R blockade might act through AT2-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

Single-nucleotide polymorphism analysis of GH, GHR, and IGF-1 genes in minipigs

Tibetan (TB) and Bama (BM) miniature pigs are two popular pig breeds that are used as experimental animals in China due to their small body size. Here, we analyzed single-nucleotide polymorphisms (SNPs) in gene fragments that are closely related to growth traits [growth hormone (GH), growth hormone receptor (GHR), and insulin-like growth factor (IGF)-1)] in these pig breeds and a large white (LW) control pig breed. On the basis of the analysis of 100 BMs, 108 TBs, and 50 LWs, the polymorphic distribution levels of GH, GHR, and IGF-1 were significantly different among these three pig breeds. According to correlation analyses between SNPs and five growth traits - body weight (BW), body length (BL), withers height (WH), chest circumference (CC), and abdomen circumference (AC) - three SNP loci in BMs and four SNP loci in TBs significantly affected growth traits. Three SNP sites in BMs and four SNP sites in TBs significantly affected growth traits. SNPs located in the GH gene fragment significantly affected BL and CC at locus 12 and BL at locus 45 in BMs, and also BW, WH, CC, and AC at locus 45 and WH and CC at locus 93 in TBs. One SNP at locus 85 in the BM GHR gene fragment significantly affected all growth traits. All indices were significantly reduced with a mixture of alleles at locus 85. These results provide more information regarding the genetic background of these minipig species and indicate useful selection markers for pig breeding programs.