Oroxylin A (OA), a natural compound extracted from Scutellaria baicalensis, demonstrates preventive potential against ultraviolet B (UVB)-induced non-melanoma skin cancer (NMSC), the most prevalent cancer worldwide with increasing incidence. Utilizing SKH-1 hairless mice exposed to UVB, this study showed that OA delayed NMSC onset and alleviated acute skin damage. Mechanistic investigations revealed its dual action: inhibiting inflammation and enhancing nucleotide excision repair (NER) by stabilizing XPA, a crucial deoxyribonucleic acid (DNA) repair protein. This stabilization occurred through OA's interaction with glucose-regulated protein 94 (GRP94), which disrupted murine double minute 2 (MDM2)-mediated XPA ubiquitination and proteasomal degradation. By maintaining XPA levels, OA expedited photoproduct clearance and diminished genomic instability, ultimately impeding NMSC development. These findings suggest OA as a promising chemopreventive agent targeting the GRP94/MDM2-XPA axis to counteract UVB-induced carcinogenesis.
Animals ; Ultraviolet Rays/adverse effects* ; Skin Neoplasms/prevention & control* ; Flavonoids/pharmacology* ; Mice ; Xeroderma Pigmentosum Group A Protein/genetics* ; Humans ; Proto-Oncogene Proteins c-mdm2/genetics* ; DNA Repair/drug effects* ; Scutellaria baicalensis/chemistry* ; Mice, Hairless ; Skin/radiation effects*

No abstract available.
Base Sequence ; Child, Preschool ; DNA/chemistry/metabolism ; Female ; Humans ; Mutation ; Nevus, Pigmented/diagnosis/*genetics ; Polymorphism, Single Nucleotide ; Proto-Oncogene Proteins p21(ras)/*genetics ; Republic of Korea ; Skin/pathology ; Skin Neoplasms/diagnosis/*genetics ; Syndrome

OBJECTIVEPreventive measures against skin melanoma like chemotherapy are useful but suffer from chronic side effects and drug resistance. Ethanolic extract of Phytolacca decandra (PD), used in homeopathy for the treatment of various ailments like chronic rheumatism, regular conjunctivitis, psoriasis, and in some skin diseases was tested for its possible anticancer potential.

METHODSCytotoxicity of the drug was tested by conducting 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on both normal (peripheral blood mononuclear cells) and A375 cells. Fluorescence microscopic study of 4',6-diamidino-2-phenylindole dihydrochloride-stained cells was conducted for DNA fragmentation assay, and changes in cellular morphology, if any, were also recorded. Lactate dehydrogenase activity assay was done to evaluate the percentages of apoptosis and necrosis. Reactive oxygen species (ROS) accumulation, if any, and expression study of apoptotic genes also were evaluated to pin-point the actual events of apoptosis.

RESULTSResults showed that PD administration caused a remarkable reduction in proliferation of A375 cells, without showing much cytotoxicity on peripheral blood mononuclear cells. Generation of ROS and DNA damage, which made the cancer cells prone to apoptosis, were found to be enhanced in PD-treated cells. These results were duly supported by the analytical data on expression of different cellular and nuclear proteins, as for example, by down-regulation of Akt and Bcl-2, up-regulation of p53, Bax and caspase 3, and an increase in number of cell deaths by apoptosis in A375 cells.

CONCLUSIONOverall results demonstrate anticancer potentials of PD on A375 cells through activation of caspase-mediated signaling and ROS generation.

Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Cell Line, Tumor ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Melanoma ; drug therapy ; genetics ; metabolism ; physiopathology ; Phytolacca ; chemistry ; Phytotherapy ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Reactive Oxygen Species ; metabolism ; Signal Transduction ; drug effects ; Skin Neoplasms ; drug therapy ; genetics ; metabolism ; physiopathology ; Up-Regulation ; drug effects

Animals ; Carcinoma, Squamous Cell ; genetics ; Colorectal Neoplasms ; genetics ; metabolism ; Enzyme Activation ; Esophageal Neoplasms ; genetics ; Genome-Wide Association Study ; Head and Neck Neoplasms ; genetics ; Humans ; Neoplasms ; chemically induced ; enzymology ; genetics ; Phosphoinositide Phospholipase C ; chemistry ; genetics ; metabolism ; physiology ; Signal Transduction ; Skin Neoplasms ; chemically induced ; enzymology ; Stomach Neoplasms ; genetics ; Urinary Bladder Neoplasms ; metabolism ; pathology ; ras Proteins ; metabolism

The expression of the p53 protein (p53) was compared with those of several oncogenes including c-fos (Fos), c-jun (Jun), and epidermal growth factor receptor (EGFR1) using immunohistochemistry in frozen and paraffin-embedded sections of 25 basal cell carcinomas (BCCs) to find out any correlation between p53 and oncogenes in the pathogenesis of human BCC. In normal skin, positive reactions were obtained for EGFR1 and Fos, while p53 and Jun were negative in all cases. In the lesions, EGFR1 was observed in all cases and p53 was positive in 9 of 25 (36%). Fos was expressed in 21 of 25 (84%) and four negative cases were all p53-positive; this negative correlation between p53 and Fos staining was statistically significant (P< 0.01). Jun was detected in 14 of 20 (70%) and no significant relationship was observed between the expression of Jun and Fos or p53. These data suggest the possibility of down regulation of Fos expression by high levels of p53 protein. Further work is necessary to determine the mechanism of this interaction.
Aged ; Carcinoma, Basal Cell/chemistry/*genetics ; Comparative Study ; Female ; Gene Expression ; Genes, fos ; Genes, jun ; Genes, p53 ; Human ; Immunohistochemistry ; Male ; Middle Age ; Oncogene Protein p65(gag-jun)/analysis ; Oncogene Proteins v-fos/analysis ; *Oncogenes ; Protein p53/analysis ; Receptor, Epidermal Growth Factor/analysis ; Skin Neoplasms/chemistry/*genetics