No abstract

Apatinib, an inhibitor of vascular endothelial growth factor receptor-2, has been shown to promote anti-cancer action across a wide range of malignancies, including gastric, lung, and breast cancers. Our previous study showed that apatinib increases apoptosis in anaplastic thyroid carcinoma (ATC), but the direct functional mechanism of tumor lethality mediated by apatinib is still unknown. In this study, we demonstrated that apatinib induced both autophagy and apoptosis in human ATC cells through downregulation of p-AKT and p-mTOR signals via the AKT/mTOR pathway. Moreover, inhibition of apatinib-induced autophagy increased apatinib-induced apoptosis in ATC cells, and additional tumor suppression was critically produced by the combination of apatinib and the autophagy inhibitor chloroquine in vivo and in vitro. These findings showed that both autophagy and AKT/mTOR signals were engaged in ATC cell death evoked by apatinib. ATC patients might benefit from the new anti-cancer drug, and molecular targeted treatment in combination with autophagy inhibitors shows promise as a treatment improvement.

Objective: We aimed to describe our experience and the learning curve of 450 cases of robot-assisted pancreaticoduodenectomy (RPD) and optimize the surgical process so that our findings can be useful for surgeons starting to perform RPD. Summary Background Data: Robotic surgical systems were first introduced 20 years ago. Pancreaticoduodenectomy (PD) is a challenging surgery because of its technical difficulty. RPD may overcome some of these difficulties. Methods: The medical records of 450 patients who underwent RPD between May 2010 and December 2018 at the Shanghai Ruijin Hospital were retrospectively analyzed. Operative times and estimated blood loss (EBL) were analyzed and the learning curve was determined. A cumulative sum (CUSUM) analysis was used to identify the inflexion points. Other postoperative outcomes, postoperative complications, and long-term follow-up were also analyzed. Results: Operative time improved gradually over time from 405.4 AE 112.9 minutes (case 1-50) to 273.6 AE 70 minutes (case 301-350) (P < 0.001). EBL improved from 410 AE 563.5 mL (case 1-50) to 149.0 AE 103.3 mL (case 351-400) (P < 0.001). According to the CUSUM curve, there were 3 phases in the RPD learning curve. The inflexion points were around cases 100 and 250. The incidence of pancreatic leak in the last 350 cases was significantly lower than that in the first 100 cases (30.0% vs 15.1%, P ¼ 0.003). Conclusions: RPD is safe and feasible for selected patients. Operative and oncologic outcomes were much improved after experience of 250 cases. Our optimization of the surgical process may have also contributed to this. Future prospective and randomized studies are needed to confirm our results.

Abstractp53R2 is a newly identified subunit of ribonucleotide reductase (RR) and plays a crucial role in supplying precursors for DNA repair in a p53-dependent manner. In our current work, all three human RR subunit proteins (p53R2, hRRM2, and hRRM1) were prokaryotically expressed and highly purified. Using an in vitro [ 3 H]CDP reduction assay, the activity of RR reconstituted with either p53R2 or hRRM2 was found to be time, concentration, and hRRM1 dependent. The kinetic activity of p53R2-containing RR was about 20 -50% lower than that of hRRM2-containing RR. Using a synthetic heptapeptide to inhibit RR activity, it was shown that p53R2 bound to hRRM1 through the same COOHterminal heptapeptide as hRRM2. However, hRRM2 had a 4.76-fold higher binding affinity for hRRM1 than p53R2, which may explain the reduced RR activity of p53R2 relative to hRRM2. Of interest, p53R2 was 158-fold more susceptible to the iron chelator deferoxamine mesylate than hRRM2, although the iron content of the two proteins determined by atomic absorption spectrometer was almost the same. To the contrary, p53R2 was 2.50-fold less sensitive than hRRM2 to the radical scavenger hydroxyurea, whereas EPR showed similar spectra of the tyrosyl radical in two proteins. Triapine, a new RR inhibitor, was equally potent for p53R2 and hRRM2. These inhibition studies showed that the iron center and tyrosyl radical are involved in RR activity for both p53R2 and hRRM2. The susceptibility differences to RR inhibitors between p53R2 and hRRM2 may lead to a new direction in drug design for human cancer treatment.