KEY POINTS
- The preclinical study tested berberine with radiation in human UM-SCC-22B HNSCC cells and murine MOC2 oral squamous carcinoma cells, complemented by 3D spheroids, EGFR-knockdown experiments and a syngeneic immunocompetent mouse model. In-vitro irradiation was 2.5 Gy, followed by cell-line-specific berberine exposure.
- Combined treatment consistently reduced proliferation, viability and clonogenic survival more than either modality alone. Apoptotic cells increased to 28% in UM-SCC-22B and 36% in MOC2 after combination treatment, accompanied by increased cleaved caspase-3/PARP and a shift toward pro-apoptotic Bax signaling.
- DNA damage increased substantially. In UM-SCC-22B cells, comet-tail length rose from 10 arbitrary units in controls to 29 after radiation alone and 39 with radiation plus berberine; corresponding MOC2 values were 5, 14 and 18, respectively. γ-H2AX expression increased concordantly.
- Mechanistically, combination treatment downregulated multiple DNA-damage-repair components and suppressed prosurvival signaling involving EGFR, ERK1/2, mTOR and STAT3. These effects provide a plausible explanation for the increased persistence of radiation-induced damage.
- Spheroid experiments showed architectural disruption and reduced stemness-associated signaling. Berberine plus radiation suppressed Wnt/β-catenin activity and decreased pluripotency/cancer-stem-cell markers including Oct4, Sox2, Nanog and CD133.
- EGFR knockdown did not abolish berberine-mediated enhancement of DNA damage or loss of stemness, suggesting that additional pathways contribute to radiosensitization. The apoptosis data, however, were compatible with a role for EGFR in the mitochondrial apoptotic response.
- In C57BL/6 mice, six animals per group received MOC2 syngrafts and were assigned to six treatment arms. Radiation was 2.5 Gy twice weekly to 15 Gy total, while berberine was given orally at 7.5 or 15 mg/kg six days per week; combination treatment reduced tumor volume and weight, with lower Ki-67 and greater cleaved PARP expression.
CLINICAL TAKEAWAY
Berberine produced a coherent radiosensitizing phenotype across clonogenic survival, DNA damage, stemness pathways and an immunocompetent mouse tumor model. The findings remain entirely preclinical and should not be interpreted as evidence for adding over-the-counter berberine to head-and-neck radiotherapy outside a properly designed clinical trial.