Objective To explore the effect and potential mechanisms of melatonin combined with gemcitabine on the chemosensitivity of human pancreatic cancer cell line PANC-1.Methods Human pancreatic cancer cell line PANC-1 was trea-ted with gemcitabine alone or in combination with melatonin.Cell viability was assessed using CCK-8.Effect of melatonin and gem-citabine alone or in combination on the clonogenic capacity of PANC-1 cells were observed through colony formation experiments.Scratch assays and transwell experiments were conducted to evaluate cell migration ability.Reactive oxygen species(ROS)and mitochondrial membrane point JC-1 assay kit were used to determine reactive oxygen species synthesis and membrane potential levels.Intracellular Fe2+level was measured using ferrous ion fluorescent probe.The protein expression levels of LC3,P62,GPX4 and SLC7A11 in different treatment groups were detected by immunofluorescence and Western blotting.Results CCK-8 results showed that the viability of PANC-1 cells was inhibited by gemcitabine alone after 48 h and 72 h of treatment in a time-and dose-dependent manner.The cell viability of gemcitabine combined with melatonin group was significantly lower than that of gemcitabine group,and the cell viability decreased with the increase of melatonin concentration.Scratch assays,transwell experiments,and plate colony formation assay results demonstrated that the proliferation and migration of cells in the gemcitabine combined with the me-latonin group were significantly inhibited compared with the gemcitabine group.The levels of reactive oxygen species and Fe2+in PANC-1 in gemcitabine combined with the melatonin group were higher than those in the gemcitabine group,and the mitochondri-al membrane potential was significantly decreased(P＜0.01).Western blotting and immunofluorescence results showed that the ra-tio of autophagy-related protein LC3-Ⅱ/LC3-Ⅰ in gemcitabine combined with the melatonin group was lower than that in the gem-citabine group,and the expression of P62 was up-regulated,and the expression of anti-iron death-related protein GPX4 and SLC7A11 was significantly inhibited(P＜0.05),suggesting that melatonin combined with gemcitabine can inhibit autophagy and promote ferroptosis in PANC-1 cells.Conclusion Melatonin enhances the chemosensitivity of pancreatic cancer cell PANC-1 to gemcitabine by inhibiting autophagy and promoting ferroptosis of tumor cells.

AIM:To investigate the effect of tea polyphenols(TP)on the sensitivity of human gastric cancer cells to oxaliplatin(L-OHP)in vitro and its mechanism.METHODS:Human gastric cancer HGC-27 and N87 cells,and human gastric mucosal GES-1 cells were used in this study.The HGC-27 and N87 cells were randomly assigned into con-trol group,TP(5 μmol/L)group,L-OHP(5.2 μmol/L for HGC-27 cells,7.7 μmol/L for N87 cells)group,and TP(5 μmol/L)combined with L-OHP(5.2 μmol/L for HGC-27 cells,7.7 μmol/L for N87 cells)group,with 3 replicate wells per group.The cell viability was detected by CCK-8 assay,and the IC50 value of L-OHP was calculated.The proliferation of the cells was assessed by colony formation assay.The migration and invasion abilities of the cells were evaluated by scratch test and Transwell assay.Flow cytometry was performed to evaluate the antiapoptotic effect of the treatments.Ade-novirus infection was conducted to evaluate cell autophagy.The levels of intracellular reactive oxygen species(ROS)were assessed using a ROS assay kit.Western blot analysis was performed to evaluate the protein expression levels of microtu-bule-associated protein 1 light chain 3(LC3),nuclear factor E2-related factor 2(Nrf2),heme oxygenase-1(HO-1)and superoxide dismutase 1(SOD1).RESULTS:Combination of TP and L-OHP significantly reduced the viability of HGC-27 and N87 cells,and markedly inhibited cell proliferation and migration compared with L-OHP alone.Significant increas-es in autophagosomes and ROS levels were observed in combination group compared with L-OHP alone group.The ratio of LC3-II/LC3-I significantly increased in combination group,whereas the expression of Nrf2,HO-1 and SOD1 significantly decreased compared with L-OHP alone group(P<0.05).CONCLUSION:Treatment with TP enhanced the sensitivity of HGC-27 and N87 cells to L-OHP by inhibiting the Nrf2 pathway,promoting the production of intracellular ROS,and in-ducing cell autophagy.

Parvalbumin interneurons belong to the major types of GABAergic interneurons. Although the distribution and pathological alterations of parvalbumin interneuron somata have been widely studied, the distribution and vulnerability of the neurites and fibers extending from parvalbumin interneurons have not been detailly interrogated. Through the Cre recombinase-reporter system, we visualized parvalbumin-positive fibers and thoroughly investigated their spatial distribution in the mouse brain. We found that parvalbumin fibers are widely distributed in the brain with specific morphological characteristics in different regions, among which the cortex and thalamus exhibited the most intense parvalbumin signals. In regions such as the striatum and optic tract, even long-range thick parvalbumin projections were detected. Furthermore, in mouse models of temporal lobe epilepsy and Parkinson's disease, parvalbumin fibers suffered both massive and subtle morphological alterations. Our study provides an overview of parvalbumin fibers in the brain and emphasizes the potential pathological implications of parvalbumin fiber alterations.
Mice ; Animals ; Epilepsy, Temporal Lobe/pathology* ; Parvalbumins/metabolism* ; Parkinson Disease/pathology* ; Neurons/metabolism* ; Interneurons/physiology* ; Disease Models, Animal ; Brain/pathology*