Protective Effects of Pyridoxamine Against UVC-induced Programmed Cell Death in HaCaT Cells.

BACKGROUND: Exposure to ultraviolet (UV) light is closely related to human diseases, such as skin cancer, due to irreversible injuries to the skin cells. The UV-induced DNA damage and programmed cell death are important determinants for skin carcinogenesis. The aim of the present study was to investigate the anti-ultraviolet-C (UVC) effects of pyridoxamine in human keratinocyte HaCaT cells and its mechanisms of action. RESULTS: UVC-induced programmed cell death in HaCaT cells was abrogated by treated the cells immediately after UVC irradiation with 40, 80 and 160 µM of pyridoxamine. Monitoring the UVC-induced-specific reactive oxygen species, we found that 20, 40, 80 and 160 µM of pyridoxamine was also effective in suppressing the induction of reactive oxygen species by UVC. CONCLUSION: Overall, our results provided evidence showing that pyridoxamine was effective in protecting HaCaT cells from UVC-induced programmed cell death and may be a potential anti-UVC agent in life and clinical practice.

Baicalin scavenges reactive oxygen species and protects human keratinocytes against UVC-induced cytotoxicity.

Long-term exposure to solar ultraviolet (UV) radiation can cause multiple skin disorders, including skin cancer. Protection against UV-induced damage is, therefore, a worldwide concern. Baicalin, a major component of traditional Chinese medicine Scutellaria baicalensis, has been reported to have antioxidant and cytostatic effects on normal epithelial and normal peripheral blood and myeloid cells. In the current study, we examined whether baicalin could also effectively protect human keratinocytes from damaging short-wave UVC irradiation. Baicalin-scavenged reactive oxygen species increased within 2 h after UVC radiation. Baicalin also abrogated UVC-induced apoptosis. In addition, we identified the major products after UVC radiation with T4 UV endonuclease, finding that baicalin prevented cyclobutane pyrimidine dimer formation induced by UVC. Furthermore, baicalin also prevented formation of oxidative adducts induced by UVC. Our results demonstrated the utility of baicalin in assessing the potential contribution of traditional Chinese medicinal agents in therapy of UVC-induced genomic damage to skin and suggest potential application of these agents as pharmaceuticals in prevention of solar-induced skin damage.

Curcumin-induced apoptosis in human hepatocellular carcinoma j5 cells: critical role of ca(+2)-dependent pathway.

The antitumor effects of curcumin, a natural biologically active compound extracted from rhizomes of Curcuma longa, have been studied in many cancer cell types including human hepatocellular carcinoma (HCC). Here, we investigated the effects of Ca(2+) on curcumin-induced apoptosis in human HCC J5 cells. The abrogation of mitochondrial membrane potential (ΔΨ(m)), the increase of reactive oxygen species (ROS) production, and calcium release were demonstrated with flow cytometry as early as 15 minutes after curcumin treatment. In addition, an increase level of cytochrome c in the cytoplasm which led to DNA fragmentation was observed. To verify the role of Ca(2+) in curcumin-induced apoptosis, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), an intracellular calcium chelator, was applied. Cell viability was increased, but ΔΨ(m), ROS production, activation of caspase 3, and cell death were decreased in J5 cells pretreated with BAPTA for 2 h followed by the treatment of 25 µM curcumin. These results suggest that the curcumin-induced apoptosis in human HCC J5 cells is via mitochondria-dependent pathway and is closely related to the level of intracellular accumulation of calcium.

DNA damage and endoplasmic reticulum stress mediated curcumin-induced cell cycle arrest and apoptosis in human lung carcinoma A-549 cells through the activation caspases cascade- and mitochondrial-dependent pathway.

Curcumin, a major component of the Curcuma species, is known to have antioxidant, anti-inflammatory properties and induce apoptosis of cancer cells, however, the precise molecular mechanisms of apoptosis in vitro are unclear. In this study, we showed that curcumin, a plant product containing the phenolic phytochemical, caused DNA damage and endoplasmic reticulum (ER) stress and mitochondrial-dependent-induced apoptosis through the activation of caspase-3 at a treatment concentration of 30 microM in human lung cancer A-549 cells. In contrast, treatment with 5-10 microM of curcumin did not induce significant apoptosis, but rather induced G2/M-phase arrest in A-549 cells. Flow cytometric analysis indicated that curcumin directly increased intracellular oxidative stress based on the cell permeable dye, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) acting as an indicator of reactive oxygen species (ROS) generation. GADD153 and GRP78 were increased by curcumin which was indicative of ER stress. Curcumin increased Ca(2+) levels and the mitochondrial membrane potential (DeltaPsi(m)), was decreased in A-549 cells. Overall, our results demonstrated that curcumin treatment causes cell death by activating pathways inducing G2/M-phase arrest and apoptosis.

Berberine induced down-regulation of matrix metalloproteinase-1, -2 and -9 in human gastric cancer cells (SNU-5) in vitro.

Berberine, a yellow benzylisoquinoline alkaloid, is a constituent of Coptis chines and is commonly used in Chinese herbal medicine for patients with gastrointestinal disorders. The pharmacological effects of berberine include anti-inflammation, antidiarrhetic, antimalarial, and even antimicrobial activities. However, its mechanism of action on the cell migration of human gastric cancer SNU-5 cells is not fully understood. The effects of berberine on the percentage of viable cells were examined first and it was found that berberine induced dose-dependent inhibition in human gastric cancer SNU-5 cells. The effect of berberine on the levels of reactive oxygen species (ROS) and matrix metalloproteinase-1, -2, -7 and -9 was then examined using Western blotting and the results showed that berberine induced ROS production for up to 6 hours of incubation. It was also found that berberine induced downregulation of MMP-1 -2, and -9 but did not affect the level of MMP-7. The mRNA levels of MMPs in SNU-5 cells after treatment with berberine for 24 hours were investigated using a polymerase chain reaction and the results showed that berberine inhibited the gene expression of MMP-1, -2 and -9 in human SNU-5 cells but it did not affect MMP-7. In conclusion, berberine appears to exert its anticancer properties by inducing ROS production and prevention of cell migration via inhibition of the gene expression of MMP-1, -2 and -9 in human gastric cancer SNU-5 cancer cells.

Effects of curcumin on N-bis(2-hydroxypropyl) nitrosamine (DHPN)-induced lung and liver tumorigenesis in BALB/c mice in vivo.

Curcumin (diferuloylmethane), a phenolic compound from the plant Curcuma longa (Linn.) has been shown to exhibit antitumor activity and apoptosis in many human cancer cell lines including that of lung and liver cancer. In this study, curcumin was evaluated in BALB/c mice for its ability to inhibit pulmonary and liver adenoma formation and growth after they were orally treated with N-bis(2-hydroxypropyl)nitrosamine (DHPN). Animals were treated with DHPN in water for approximately 14 days before multiple doses of curcumin were given intraperitoneally. It was found that 200 microM curcumin reduced lung and liver tumor multiplicity by 37% (p<0.05) and 30% (p<0.05) respectively. The results indicated that curcumin significantly inhibited pulmonary and liver adenoma formation and growth in BALB/c mice. The precise mechanism by which curcumin inhibits lung and liver tumorigenesis remains to be elucidated. Thus, curcumin appears to be a promising new chemotherapeutic and preventive agent for lung and liver cancer induced by DHPN.