The expression of mammalian target of rapamycin and its substrates in autogenous vein graft in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of mammalian target of rapamycin (mTOR) and its substrates including p70s6k and 4E-BP1 in autogenous vein graft.</p><p><b>METHODS</b>Autogenous vein graft model was established in 64 Wistar rats by transplanting the right common jugular vein to infrarenal abdominal aorta. Vein graft samples were harvested 6 hours, 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks and 8 weeks after surgery. The mRNA expression of mTOR, p70s6k and 4E-BP1 were measured by RT-PCR and in situ hybridization. Western blot and immunohistochemistry methods also were used to detect the protein expression of mTOR, p70s6k and 4E-BP1. Proliferating cell nuclear antigen (PCNA) was also detected at the same time.</p><p><b>RESULTS</b>The mRNA expression of mTOR and p70s6k increased soon after vein graft transplanting, rose quickly and reached the peak 3 days to 2 weeks after surgery, which recovered 6 to 8 weeks after surgery. The expression of 4E-BP1 mRNA decreased soon after surgery and reached the lowest at 1 week, then rose to the peak 4 to 6 weeks after transplantation. Protein expression of mTOR and p70s6k reached the peak 2 to 4 weeks and recovered to normal level 8 weeks after surgery, but the expression of 4E-BP1 decreased to the lowest during 1 to 2 weeks and reached the peak 4 to 6 weeks after transplanting. The positive cells mostly located in vascular smooth muscle cell (VSMC) just like PCNA.</p><p><b>CONCLUSIONS</b>The expression of mTOR and its substrates were activated in vein graft soon after transplantation, which means that mTOR and its substrates might become new targets for the prevention and therapy of stenosis or obliteration after vein graft transplanting.</p>

Mechanism of reversal of multidrug resistance in human renal carcinoma cells by protein kinase C inhibitor / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the mechanism of reversal of multidrug resistance in renal carcinoma cells by protein kinase C inhibitor.</p><p><b>METHODS</b>RT-PCR, Western blot and inverted fluorescent microscopy were used to determine the expression of PKCalpha and MDR related gene MDR1, MRP1, LRP in RCC cells transferred by PKCalpha cDNA. Also effects of activator and inhibitor of PKC in combination with adriamycin on multidrug resistance in RCC cells were evaluated by MTT.</p><p><b>RESULTS</b>The results of semi-quantitative RT-PCR analysis showed that the expression level of MDR1 was higher in RCC cells transferred by PKCalpha cDNA than in RCC cells, the reversal effectiveness of PKC inhibitors in combination with adriamycin (ADM) was apparently favorable. IC(50) of ADM in 786 - 0 cells was 7.8015e(-7) (5.7046e(-7) to 1.0669e(-6)); IC(50) of ADM in PKCalpha/786 - 0 cells was 1.6588e(-6) (1.1621e(-6) to 2.3677e(-6)); IC(50) of ADM in combination with PMA in PKCalpha/786 - 0 cells was 2.6794e(-6) (2.0521e(-6) to 3.4983e(-6)); IC(50) of ADM in combination with calphostin C in PKCalpha/786 - 0 cells was 9.2506e(-8) (5.9337e(-8) to 1.4422e(-7)).</p><p><b>CONCLUSION</b>PKC inhibitors can reverse multidrug resistance in renal carcinoma cells in vitro via changes of expression of MDR1.</p>

The role of protein kinase C alpha in recurrence of superficial bladder carcinoma / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the relationship of protein kinase C-alpha (PKCalpha) expression/activation with tumor differentiation and resistance to chemotherapy drugs in superficial bladder carcinoma.</p><p><b>METHODS</b>Expression of PKCalpha was measured by Western-blot analysis in 76 samples including tumor and normal tissues, respectively. A human RT4 bladder cancer cell line stably expressing green fluorescent protein (GFP)-PKCalpha (RT4/PKCalpha) was established. The sensitivity of the RT4/PKCalpha and parental cells to adriamycin (ADM) was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The change of sensitivity of the RT4/PKCalpha to ADM were observed under the conditions of PKC activation and inhibition, respectively.</p><p><b>RESULTS</b>Total level of PKCalpha expression and the ratio of the amount of PKCalpha expression or PKC activity in membrane to that in cytosol (M/C) were all more higher in cancerous tissues than in normal tissues (P < 0.01); With the increase of tumor grade, the relative level of PKCalpha expression significantly increased in membrane (P < 0.01) and decreased in cytosol (P < 0.01), M/C of PKCalpha was significantly elevated (P < 0.01), and total relative level of PKCalpha expression significantly increased (P < 0.01). Thirty-eight cases recurred during the follow-up period in total seventy cases. Multivariate analysis showed that high M/C of PKCalpha was independent prognostic factor for tumor recurrence after standard ADM treatment in the 2-year follow-up (RR = 3.98, 95% CI 1.22-5.68, P = 0.03). Transfection of PKCalpha increased resistance of RT4 cells to ADM [resistance index (RI): 6.97, t = 3.24, P < 0.01]. PKCalpha activation further greatly promoted the resistance (RI: 148.11, t = 5.18, P < 0.001) while inhibition of PKCalpha did conversely (RI: 1.6, t = 1.29, P > 0.05).</p><p><b>CONCLUSION</b>The abnormal activation and expression level of PKCalpha closely correlate with both tumor grade and intrinsic resistance to ADM in patients with superficial bladder carcinoma.</p>

Sequencing and bioinformatic analysis of NRDRiso cDNA / 生物工程学报

This study describes the cDNA sequencing and the bioinformatic analysis of a novel NADP(H)-dependent retinol dehydrogenase/reductases isoform (NRDRiso). Based upon the concensus sequences of human and mouse NRDR coding region, we have identified a short 377 bp RT-PCR product from human liver tissue. The cDNA sequence of a NRDR isoform was then isolated using RACE approach and its sequence was analysed. The full-length cDNA is 1,003bp in length and was submitted to GenBank as NADP-dependent retinol dehydrogenase/reductase short isoform (NRDRiso). The open reading frames of NRDRiso cDNA is 525 bp.