Search

Objective To investigate mechanism and effect on (-)-gossypol enhancing epirubicin killing hepatocellular carcinoma (HCC) cells. Methods HCC cells (Hep 3B and HuH7) were divided into 8 groups: control, (-)-gossypol, epirubicin, combination, si-control+epirubicin, si-X-linked inhibitor of apoptosis protein (XIAP)+ epirubicin, empty vector+ combination and pEBB-XIAP+ combination groups. Cell viability of each group was detected by CCK-8 assay; Cell apoptosis of each group was detected by flow cytometry and the level of cleavaged PARP, XIAP and eIF4E phosphorylation was detected by Western blot assay. Results Compared with the control group, no major effect was observed on cell viability exposed to (-)-gossypol in 5 μmol/L (P>0.05). Combination of (-)-gossypol and epirubicin significantly enhanced the anti-survival effect on HCC cells (P < 0.05), promoted cells apoptosis, increased the induction of cleavaged PARP, and inhibited XIAP up-regulation and eIF4E phosphorylation induced by epirubicin in HCC cells. Silencing XIAP promoted epirubicin to kill HCC cells and induced PARP cleavaged; Furthermore, XIAP over-expression attenuated epirubicin-induced anti-survival and pro-apoptosis of HCC cells enhanced by (-)-gossypol. Conclusion The combination of (-)-gossypol and epirubicin significantly inhibits HCC cells' survival and promotes cell apoptosis via suppressing epirubicin-induced phosphorylation of eIF4E and up-regulation of XIAP, suggesting that (-)-gossypol holds promise as a sensitizer for epirubicin-based HCC therapy.

Open-cathode air-cooled proton exchange membrane fuel cell stack relies on air fans both for fuel supply and stack cooling. Inappropriate stack thermal management and non-uniform temperature distribution can lead to compromised stack performance, reduced lifespan, and even thermal runaway. Thus, temperature distribution measurement, investigation and analysis are essential for air-cooled PEMFC's optimized operation and performance. This study uses a multi-zone temperature measurement approach to investigate the impact of air supply method, airflow, and output current on stack temperature distributions. The experimental results reveal that the highest stack temperature occurs at the cathode channel outlet, while the lowest temperature is near the hydrogen inlet. At a 75A load, the maximum temperature difference between the inlet and outlet is 17°C. Increasing fan speed from 4500 to 8800 r/min reduces temperature non-uniformity in cell 10, the most uneven among the 19 cells, by 11.2%. Comparing blowing and suction air supply modes, blowing enhances stack output performance by 2.1%, with smaller temperature differences. Specifically, cell 10 experiences a 7.5°C lower difference at 4500 r/min and a 3.6°C lower difference at 8800 r/min airflow. Under blowing air supply, temperature non-uniformity decreases by 36.95% at 4500 r/min and 29.2% at 8800 r/min. [ABSTRACT FROM AUTHOR]

The electro-generation of acyl radicals from both aromatic and aliphatic aldehydes remains an unmet challenge. We provide a solution to this challenge by merging electro-oxidation and a quinuclidine-mediated hydrogen atom transfer strategy. The generation of acyl radicals at decreased applied potentials compared to that of formyl oxidation exhibits excellent functional group compatibility. [ABSTRACT FROM AUTHOR]

Objective To investigate the significance of down-regulating the miR-4443/TIMP2 pathway on sorafenib sensitivity in HepG2 cells. Methods HepG2 cells were divided into control group (DMSO) and sorafenib treatment group (10 μmol/L). After treatment for 24 h, the mRNA level of miR-4443 was measured by RT-qPCR. CCK-8 assay was used to study the effects of transfection with miR-4443 mimics or pretreatment of its inhibitor on the cell viability of HepG2 cells treated with sorafenib for 24 h. Bioinformatics analysis was used to predict the downstream target gene of miR-4443. The expression of TIMP2 at mRNA and protein levels was assessed by RT-qPCR and Western blotting in the HepG2 cells treated with sorafenib for 24 h, transfected with miR-4443 mimics or pretreatment of its inhibitor followed by sorafenib treatment. Then TIMP2 siRNA was transfected into HepG2 cells by liposome transfection, the content of TIMP2 protein was detected by Western blotting, and the effect of TIMP2 knockdown combined with sorafenib treatment on the viability of HepG2 cells was measured with CCK-8 assay. Results Sorafenib treatment decreased the expression of miR-4443 in HepG2 cells (P < 0.05). Overexpression of miR-4443 (transfection of miR-4443 mimics) significantly decreased the inhibitory effect of sorafenib on cell viability (P < 0.05), while pretreatment of miR-4443 inhibitor could enhance the effect of the drug (P < 0.05). Bioinformatics analysis indicated that the downstream target gene of miR-4443 was TIMP2. The mRNA and protein levels of TIMP2 were obviously increased in HepG2 cells after sorafenib treatment (P < 0.05), but the transfection of miR-4443 mimics or pretreatment of its inhibitor would down- or up-regulate the mRNA level of TIMP2, and the transfection of miR-4443 mimics decreased the protein level of TIMP2, indicating the regulative relationship between the 2 molecules. The transfection of TIMP2 siRNA decreased the expression of TIMP2 and then enhanced the inhibitory effect of sorafenib on HepG2 viability (P < 0.05). Conclusion Down-regulation of the miR-4443/TIMP2 pathway enhances sorafenib sensitivity in HepG2 cells.

Objective To investigate the effect of activating the miR-101-3p/EZH2 pathway on sorafenib sensitivity of HepG2 cells. Methods HepG2 cells treated with sorafenib (10 μmol/L) for 24 h were examined for protein expression of enhancer of zeste homolog 2 (EZH2) using Western blotting and for mRNA expression of EZH2 and miR-101-3p using RT-qPCR. The interaction between miR-101-3p and EZH2 mRNA was analyzed through informatics analysis and verified using dual luciferase reporter assay. HepG2 cells were transfected with miR-101-3p mimic or treated with the EZH2 inhibitor EPZ-6438 followed by treatment with sorafenib for 24 h, and the change in cell proliferation was assessed using CCK-8 assay. Results Sorafenib obviously decreased the expression of miR-101-3p in HepG2 cells (P < 0.05). Informatics analysis showed that miR-101-3p could bind to the 3'-UTR of EZH2 mRNA, and transfection with miR-101-3p significantly inhibited the expression of EZH2 in HepG2 cells (P < 0.05). Sorafenib treatment significantly increased the expression of EZH2 in HepG2 cells (P < 0.05). Both miR-101-3p over-expression and EPZ-6438 treatment resulted in significantly increased sorafenib sensitivity of HepG2 cells (P < 0.05). Conclusion Activation of the miR-101-3p/EZH2 pathway can enhance sorafenib sensitivity of HepG2 cells.

Objective To investigate the synergistic effect of dichloroacetate (DCA) and sorafenib on the inhibition of proliferation in hepatocellular carcinoma (HCC) cells. Methods Hep3B cells were treated respectively, with DMSO (control), DCA (5 mmol/L), sorafenib (10 μmol/L), and DCA (5 mmol/L) combined with sorafenib (10 μmol/L) for 24 h, then the cells were stained with crystal violet and observed under a microscope for cell morphology. CCK-8 assay was used to detect the changes of cell proliferation, and flow cytometry was employed to measure cell apoptosis. Then, Western blotting was utilized to detect the protein expression of apoptosis-related protein PARP and p-JNK, and the production of reactive oxygen species (ROS) was measured by ROS detection kits, Finally, flow cytometry was performed to detect the changes of apoptosis after addition of anti-oxidant, NAC and JNK inhibitor, SP600125. Results DCA combined with sorafenib significantly changed the cell morphology and killed the cells. Compared with DCA alone or sorafenib alone, DCA combined sorafenib significantly enhanced the inhibitory effect on the proliferation in Hep3B cells (P < 0.05), increased the cleavage of PARP and the phosphorylation of JNK. Moreover, the combination induced the production of intracellular ROS (P < 0.05). Co-treatment of antioxidant NAC resulted in significant inhibition of elevated JNK phosphorylation and inhibitory effect on proliferation induced by DCA combined sorafenib in Hep3B cells. Conclusion Combination of DCA and sorafenib significantly inhibits proliferation in Hep3B cells, which may be related with the activation of ROS/JNK signal pathway.