In order to evaluate the effects and mechanisms of celecoxib in inhibiting proliferation and inducing apoptosis on human pancreatic carcinoma cells, the anti-proliferative effect was measured by using methabenzthiazuron (MTT) assay. Cell cycle and apoptosis were analyzed by using flow cytometry (FCM), and the PGE2 levels in the supernatant of cultured pancreatic carcinoma cells were quantitated by enzyme-linked immunoabsordent assay (ELISA). Our results showed that celecoxib suppressed the production of PGE2 and inhibited the growth of JF-305 cells, and the anti-proliferative effect of celecoxib could be abolished by addition of PGE2. FCM revealed that celecoxib could inhibit proliferation and induce apoptosis by G1-S cell cycle arrest. It was concluded that cyclooxygenase-2 specific inhibitor celecoxib could inhibit proliferation and induced apoptosis of human pancreatic carcinoma cells via suppression of PGE2 production in vitro.
To investigate role of Notch1–3 in hyperoxia-induced lung injury in newborn rat exposed to 85% O2, SD rat litters born on the 22th day were randomly divided into two groups: room air group and hyperoxia group. The animals were sacrificed 1, 4, 7, 10, 14 and 21 days after continued exposure to oxygen (n=40, oxygen>0.85) or room air (n=40). 6 rats each group were used to assess lung histological changes by HE staining and expression of Notch in lungs by immunohistochemistry. Total RNA was extracted by Trizol reagent from frozen lung tissues. Notch mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). Our results showed that 7, 14 and 21 days after O2 exposure, hyperoxia group showed lung injury characterized by pulmonary edema, hemorrhage and lung development arrest. Positive staining for Notch1, Notch 2 in hyperoxia group was much lower than those in room air group at all time points (P<0. 01,P<0.05), but compared with the controls, the hyperoxia group showed higher expression of Notch3 (P>0.05). Immunostained cells were typically airways epithelia, alveolar epithelial and inflammatory cells, and fibroblasts in hyperoxia group (P<0.01). Notch mRNA levels showed similar change as protein level (P<0.01). It is concluded that the prolonged exposure to 85% O2 resulted in abnormal expression of Notch receptors, which might contribute to the pathogenesis of hyperoxia-induced lung injury in newborn rats. The decreased inhibition of Notch1 might be one of the protective reaction and major mechanisms for proliferation/differentiation of type II alveolar epithelial cells. The up-regulation of Notch3 activity might result in the lung development arrest of the newborn rats.
To investigate the effect of cigarette smoke extract (CSE) on the role of protein kinase C (PKC) in the proliferation of passively sensitized human airway smooth muscle cells (HASMCs). After synchronization of cultured HASMCs, they were divided into a group A and Group B. The group A was treated with normal human serum and served as controls and the group B was treated with the serum of asthma patients. The group A was further divided into group of A1, A2 and A3 and the group B was sub-divided into the group of B1, B2, B3, B4 and B5. No other agents were added to the group A1 and B1. The cells of group A2 and B2 were stimulated with 5 % CSE for 24 h. HASMCs from group A3 and B3 were treated with PKC agonist PMA (10 nmol/L) and CSE (5 %) for 24 h. PKC inhibitor Ro-31-8220 (5 μmol/L) was added to the HASMCs of group B4 for 24 h. The cells from group B5 were stimulated with Ro-31-8220 (5 μmol/L) and CSE (5 %) for 24 h. The proliferation of HASMCs isolated from group A and B was examined by cell cycle analysis, MTT colorimetric assay and3H-TdR incorporation test. The expression of PKC-α in each group was observed by Western blotting and RT-PCR, respectively. The results showed that the percentage of S phase, absorbance (A) value, the rate of3H-TdR incorporation, the ratios ofA value of PKC-α mRNA and theA value of PKC-α protein in HASMCs from group B1, B2 and B3 were significantly increased compared to those of group A1, A2 and A3 correspondingly and respectively (P<0.01). The proliferation of HASMCs of group A2 and B2 stimulated with CSE and group A3 and B3 stimulated with CSE and PMA were also significantly enhanced when group A1, A2 and A3 and group B1, B2 and B3 compared to each other (P<0.05,P<0.01, respectively). The percentage of S phase, absorbency (A) value,3H-TdR incorporation rate, the ratios ofA value of PKC-α mRNA and theA value of PKC-α protein in HASMCs from group B4 treated with Ro-31-8220 and group B5 treated with CSE and Ro-31-8220 were significantly decreased as compared to those of group B1 and B2 correspondingly and respectively (P<0.05,P<0.01). It was concluded that CSE can enhance the passively sensitized HASMC proliferation and the expression of PKC alpha. PKC and its alpha subtype may contribute to this process. Our results suggest cigarette may play an important role in ASMCs proliferation of asthma through PKC signal pathway.
To observe the effects of calcium dobesilate on the expression of glomerular tissue inhibitor of metalloproteinase 1 (TIMP1), collagen IV, and ultrastructure of glomerular basement membrane in diabetic rats, rats model of diabetes was established by unilateral nephrectomy and intraperitoneal injection of 1% STZ (55 mg/kg), and rats were administered calcium dobesilate 100 mg/kg (DD group) or distilled water (DM group) respectively. 12 weeks later, the changes in the renal ultrastructure and creatinine clearance rate (Cer) were examined in each group. The expression of glomerular TIMP1 and collagen IV were studied by immunohistochemical staining. Our results showed that after 12 weeks, the Cer in DD group increased and was significantly higher than that in DM group. Electron microscopy showed that thickness of glomerular capillary basement membrane (GBM) in Group DD was less than that of DM group. No hyperplasia of collagen fibers was found, and the distance between the holes of endothelial cells in DD group was not as even as that in the normal group, but more even than that of DM group, and podocyte processes was still in order. Immunohistochemical staining of glomeruli showed that expression of TIMP1 and collagen IV in DD group were significantly less than those of DM group DM. It is concluded that calcium dobesilate can improve diabetic nephropathy by inhibiting the over- accumulation of collagen IV and calcium dobesilate may also contribute to diabetes by inhibiting the expression of TIMP1.