Caffeic acid (CA) is a naturally occurring phenolic compound known for its strong antioxidant and cytoprotective properties.Particulate matter (PM) with an aerodynamic diameter of 2.5 μm (PM2.5) or less is a major atmospheric pollutant that induces excessive oxidative stress and apoptosis in human skin cells, contributing to various adverse effects on the skin. In this study, we investigated the protective role of CA against PM2.5-induced cellular injury in human HaCaT keratinocytes. CA reduced PM2.5-induced reactive oxygen species (ROS) accumulation and mitigated oxidative damage, including lipid peroxidation, protein carbonyl formation, mitochondrial membrane depolarization, and intracellular calcium overload. In addition, CA attenuated PM2.5-induced apoptosis by upregulating B-cell lymphoma 2 (Bcl-2) and suppressing Bcl-2-associated X protein (Bax), caspase-3, caspase-9, and phosphorylated c-Jun N-terminal kinase (phospho-JNK). Collectively, these findings demonstrate that CA protects HaCaT keratinocytes from PM2.5-induced oxidative stress and apoptosis by regulating the Bcl-2/Bax axis and inhibiting JNK-mediated apoptotic signaling, highlighting its potential as a therapeutic candidate for preventing pollutant-induced skin damage.

Connecting peptide (C-peptide), a byproduct of insulin biosynthesis, has diverse cellular and biological functions. Particulate mat-ter 2.5 (PM2.5 ) adversely affects human skin, leading to skin thickening, wrinkle formation, skin aging, and inflammation. This study aimed to investigate the protective effects of C-peptide against PM2.5 -induced damage to skin cells, focusing on oxidative stressas a key mechanism. C-peptide mitigated NADPH oxidation and intracellular reactive oxygen species (ROS) production inducedby PM2.5 . It also suppressed PM2.5 -induced NADPH oxidase (NOX) activity and alleviated PM2.5 -induced NOX1 and NOX4 expression. C-peptide protected against PM2.5 -induced DNA damage, lipid peroxidation, and protein carbonylation. Additionally, C-peptide mitigated PM2.5 -induced apoptosis by inhibiting intracellular ROS production. In summary, our findings suggest that C-peptide mitigates PM2.5 -induced apoptosis in human HaCaT keratinocytes by inhibiting intracellular ROS production and NOX activity.

γ-Radiation resistance is a major obstacle to the success of radiotherapy in colorectal cancer. Antioxidant-related factors contribute to resistance to radiation therapy and, therefore, are targets for improving the therapeutic response. In this study, we evaluated the molecular mechanisms underlying γ-radiation resistance using the colorectal cancer cell line SNUC5 and γ-radiation-resistant variant SNUC5/RR, including analyses of the role of nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor that regulates antioxidant enzymes, and related epigenetic regulators. Reactive oxygen species (ROS) levels, antioxidant enzyme expression, NRF2 expression, and nuclear translocation were higher in SNUC5/RR cells irradiated with or without 8 Gy than in SNUC5 cells. The DNA demethylase ten-eleven translocation 1 (TET1) expression and TET1 binding to the NRF2 promoter in SNUC5/RR cells were stronger than those in SNUC5 cells, indicating lower methylation of CpG islands in the NRF2 promoter.TET1 knockdown in SNUC5/RR cells suppressed NRF2 expression significantly. Additionally, histone mixed-lineage leukemia (MLL), a histone methyltransferase, was upregulated, leading to increased trimethylation of histone H3 lysine 4, whereas enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, was downregulated, leading to decreased trimethylation of histone H3 lysine 27. Histone deacetylase (HDAC) and histone acetyltransferase (HAT) levels were lower and higher in SNUC5/RR cells than in SNUC5 cells, respectively. MLL and HAT knockdown in SNUC5/RR cells irradiated with or without 8 Gy decreased levels of NRF2 and heme-oxygenase 1, resulting in enhanced γ-radiation sensitivity. These findings support NRF2 as a target for improving the response to radiotherapy in patients with colorectal cancer.

Connecting peptide (C-peptide), a byproduct of insulin biosynthesis, has diverse cellular and biological functions. Particulate mat-ter 2.5 (PM2.5 ) adversely affects human skin, leading to skin thickening, wrinkle formation, skin aging, and inflammation. This study aimed to investigate the protective effects of C-peptide against PM2.5 -induced damage to skin cells, focusing on oxidative stressas a key mechanism. C-peptide mitigated NADPH oxidation and intracellular reactive oxygen species (ROS) production inducedby PM2.5 . It also suppressed PM2.5 -induced NADPH oxidase (NOX) activity and alleviated PM2.5 -induced NOX1 and NOX4 expression. C-peptide protected against PM2.5 -induced DNA damage, lipid peroxidation, and protein carbonylation. Additionally, C-peptide mitigated PM2.5 -induced apoptosis by inhibiting intracellular ROS production. In summary, our findings suggest that C-peptide mitigates PM2.5 -induced apoptosis in human HaCaT keratinocytes by inhibiting intracellular ROS production and NOX activity.

γ-Radiation resistance is a major obstacle to the success of radiotherapy in colorectal cancer. Antioxidant-related factors contribute to resistance to radiation therapy and, therefore, are targets for improving the therapeutic response. In this study, we evaluated the molecular mechanisms underlying γ-radiation resistance using the colorectal cancer cell line SNUC5 and γ-radiation-resistant variant SNUC5/RR, including analyses of the role of nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor that regulates antioxidant enzymes, and related epigenetic regulators. Reactive oxygen species (ROS) levels, antioxidant enzyme expression, NRF2 expression, and nuclear translocation were higher in SNUC5/RR cells irradiated with or without 8 Gy than in SNUC5 cells. The DNA demethylase ten-eleven translocation 1 (TET1) expression and TET1 binding to the NRF2 promoter in SNUC5/RR cells were stronger than those in SNUC5 cells, indicating lower methylation of CpG islands in the NRF2 promoter.TET1 knockdown in SNUC5/RR cells suppressed NRF2 expression significantly. Additionally, histone mixed-lineage leukemia (MLL), a histone methyltransferase, was upregulated, leading to increased trimethylation of histone H3 lysine 4, whereas enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, was downregulated, leading to decreased trimethylation of histone H3 lysine 27. Histone deacetylase (HDAC) and histone acetyltransferase (HAT) levels were lower and higher in SNUC5/RR cells than in SNUC5 cells, respectively. MLL and HAT knockdown in SNUC5/RR cells irradiated with or without 8 Gy decreased levels of NRF2 and heme-oxygenase 1, resulting in enhanced γ-radiation sensitivity. These findings support NRF2 as a target for improving the response to radiotherapy in patients with colorectal cancer.

Connecting peptide (C-peptide), a byproduct of insulin biosynthesis, has diverse cellular and biological functions. Particulate mat-ter 2.5 (PM2.5 ) adversely affects human skin, leading to skin thickening, wrinkle formation, skin aging, and inflammation. This study aimed to investigate the protective effects of C-peptide against PM2.5 -induced damage to skin cells, focusing on oxidative stressas a key mechanism. C-peptide mitigated NADPH oxidation and intracellular reactive oxygen species (ROS) production inducedby PM2.5 . It also suppressed PM2.5 -induced NADPH oxidase (NOX) activity and alleviated PM2.5 -induced NOX1 and NOX4 expression. C-peptide protected against PM2.5 -induced DNA damage, lipid peroxidation, and protein carbonylation. Additionally, C-peptide mitigated PM2.5 -induced apoptosis by inhibiting intracellular ROS production. In summary, our findings suggest that C-peptide mitigates PM2.5 -induced apoptosis in human HaCaT keratinocytes by inhibiting intracellular ROS production and NOX activity.

γ-Radiation resistance is a major obstacle to the success of radiotherapy in colorectal cancer. Antioxidant-related factors contribute to resistance to radiation therapy and, therefore, are targets for improving the therapeutic response. In this study, we evaluated the molecular mechanisms underlying γ-radiation resistance using the colorectal cancer cell line SNUC5 and γ-radiation-resistant variant SNUC5/RR, including analyses of the role of nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor that regulates antioxidant enzymes, and related epigenetic regulators. Reactive oxygen species (ROS) levels, antioxidant enzyme expression, NRF2 expression, and nuclear translocation were higher in SNUC5/RR cells irradiated with or without 8 Gy than in SNUC5 cells. The DNA demethylase ten-eleven translocation 1 (TET1) expression and TET1 binding to the NRF2 promoter in SNUC5/RR cells were stronger than those in SNUC5 cells, indicating lower methylation of CpG islands in the NRF2 promoter.TET1 knockdown in SNUC5/RR cells suppressed NRF2 expression significantly. Additionally, histone mixed-lineage leukemia (MLL), a histone methyltransferase, was upregulated, leading to increased trimethylation of histone H3 lysine 4, whereas enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, was downregulated, leading to decreased trimethylation of histone H3 lysine 27. Histone deacetylase (HDAC) and histone acetyltransferase (HAT) levels were lower and higher in SNUC5/RR cells than in SNUC5 cells, respectively. MLL and HAT knockdown in SNUC5/RR cells irradiated with or without 8 Gy decreased levels of NRF2 and heme-oxygenase 1, resulting in enhanced γ-radiation sensitivity. These findings support NRF2 as a target for improving the response to radiotherapy in patients with colorectal cancer.

Objective To investigate the effects of raddeanin A(RA)on the proliferation and apoptosis of HCT116 cells and on the β-catenin/c-Myc pathway.Methods Human colon cancer HCT116 cells were divided into four groups:Control group,experimental-L group,experimental-M group and experimental-H group.Experimental-L,experimental-M,experimental-H groups were treated with 5,10 and 20 μmol·L-1raddeanin A,and the control group was given the same amount of normal saline,respectively.The inhibitory effect of RA on the proliferation of HCT116 cells of colon cancer was detected by cell counting kit-8(CCK-8)method.Cell nucleus morphology change was observed with the fluorescence;the apoptosis rate was detected by flow cytometry;and the expression of related proteins of β-catenin/c-Myc signaling pathway was detected by western blot.Results After 48 h,the cell inhibitory rates of the control group,experimental-L,experimental-M,experimental-H groups were 0,(19.15±0.65)％,(35.11±0.40)％and(49.93±1.13)％,respectively;the cell apoptosis rates were(0.16±0.18)％,(9.26±0.42)％,(17.87±2.54)％and(38.10±2.70)％,respectively;the protein expression levels of β-catenin were 0.74±0.03,0.69±0.01,0.33±0.02 and 0.16±0.04,respectively;the protein expression levels of c-Myc were 0.89±0.01,0.54±0.03,0.29±0.03 and 0.13±0.04,respectively;the protein expression levels of Cyclin D1 were 0.84±0.04,0.66±0.01,0.48±0.06 and 0.21±0.03,respectively;the expression levels of Cleaved-Caspase3 protein were 0.19±0.03,0.26±0.04,0.45±0.04 and 0.78±0.01,respectively.The above indicators in the experimental-L,experimental-M,experimental-H groups showed statistically significant differences compared to those of control group(all P＜0.05).Conclusion RA can inhibit the proliferation of HCT116 cells and induce apoptosis,which may be related to the inhibition of β-catenin/c-Myc signaling pathway.

Objective To investigate the effects of acetylshikonin on proliferation,invasion and migration of oxaliplatin-resistant human colon cancer HCT116 cells(HCT116/L-OHP).Methods HCT116/L-OHP cells were divided into blank group,control group,experimental-L group,experimental-M group and experimental-H group.The control group was treated with 10 μmol·L-1 oxaliplatin.The experimental-L,experimental-M,experimental-H groups were treated with 1.25,2.50 and 5.00 μmol·L-1 acetylshikin and 10 μmol·L-1 oxaliplatin,respectively.The blank group was given routine culture.The changes of HCT116/L-OHP cell proliferation were detected by cell counting kit-8(CCK-8)method;flow cytometry was used to evaluate the apoptosis of cells;Transwell assay was used to detect the changes of cell migration and invasion ability;Western blot was used to detect the expressions of P-glycoprotein(P-gp),matrix metallo-proteinases 2(MMP2),nuclear factor kappa-B(NF-κB)/and hypoxia induced factor-1 α(HIF-1α)proteins.Results The cell inhibition rates of the blank group,control group and experimental-L,-M,-H groups were 0,(8.27±0.01)％,(10.53±0.02)％,(34.17±0.01)％and(48.47±0.05)％;cell apoptosis rates were(0.13±0.02)％,(1.37±1.04)％,(9.73±0.87)％,(26.71±4.26)％and(40.75±4.70)％;invading cells were 130.70±9.81,127.10±9.21,71.83±3.57,28.83±1.87 and 19.63±6.11;the number of migration cells was 150.50±10.17,148.40±8.13,94.58±4.09,63.98±5.09 and 31.85±5.50;the relative expression levels of P-gp protein were 0.91±0.01,0.89±0.02,0.75±0.04,0.61±0.07 and 0.25±0.03;the relative expression levels of MMP2 protein were 1.24±0.01,1.22±0.02,0.96±0.01,0.53±0.01 and 0.16±0.02;the relative expression levels of NF-κB-p65 were 1.12±0.12,1.07±0.01,0.78±0.01,0.64±0.02 and 0.31±0.03;the relative expression levels of HIF-1 α were 0.65±0.04,0.52±0.03,0.41±0.02,0.35±0.03 and 0.09±0.01,respectively.The above indicators in the experimental-L,-M,-H groups showed statistically significant differences compared to those of blank group(all P＜0.05).Conclusion Acetylshikonin combined with oxaliplatin can significantly inhibit the proliferation,invasion and migration of HCT116/L-OHP cells,and induce cell apoptosis,which may be related to the inhibition of P-gp and MMP2 expression and the activation of NF-κB/HIF-1 α signal.