Oroxylin A inhibits UVB-induced non-melanoma skin cancer by regulating XPA degradation

Chin J Nat Med. 2025 Jun;23(6):742-753. doi: 10.1016/S1875-5364(25)60893-4.

Abstract

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.

Keywords: GRP94; MDM2; Non-melanoma skin cancer; Oroxylin A; XPA.

MeSH terms

  • Animals
  • DNA Repair / drug effects
  • Flavonoids* / administration & dosage
  • Flavonoids* / pharmacology
  • Humans
  • Mice
  • Mice, Hairless
  • Proto-Oncogene Proteins c-mdm2 / genetics
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Scutellaria baicalensis / chemistry
  • Skin / drug effects
  • Skin / radiation effects
  • Skin Neoplasms* / drug therapy
  • Skin Neoplasms* / etiology
  • Skin Neoplasms* / genetics
  • Skin Neoplasms* / metabolism
  • Skin Neoplasms* / prevention & control
  • Ultraviolet Rays / adverse effects
  • Xeroderma Pigmentosum Group A Protein* / genetics
  • Xeroderma Pigmentosum Group A Protein* / metabolism

Substances

  • 5,7-dihydroxy-6-methoxy-2-phenylchromen-4-one
  • Flavonoids
  • Xeroderma Pigmentosum Group A Protein
  • Proto-Oncogene Proteins c-mdm2