A Novel Combination of Melittin and Palbociclib for Esophageal Cancer: In Vitro Evidence of Synergy and Mechanistic Insights

Abstract

Objective: To measured the possible synergistic effect of melittin in combination with palbociclib against KYSE-30 esophageal squamous cell carcinoma cells.

Study Design: A inivtro study.
Place and Duration of Study: This study was conducted at the College of Medicine, University of Babylon, Iraq from 1st June 2025 to 30th November 2025.

Methods: KYSE-30 and HEK normal cells were treated with melittin (0.15625-20 μg/mL) and palbociclib (0.625- 80 μg/mL) and then KYSE-30 were treated with combination of these two substances. Using the MTT test, we calculated the cell viability. The cyclin-D1, Nrf2 and IL-6 concentrations using enzyme-linked immunosorbent assay. Cell migration was assessed by wound healing assay.

Results: Melittin (5-10 μg/mL) significantly reduced KYSE-30 viability (p < 0.05) but only affected HEK cells at 20 μg/mL (p<0.001). Palbociclib (20-80 μg/mL) reduced KYSE-30 viability with an IC50 of 22 μg/mL. Palbociclib
alone significantly increased cyclin-D1 (P<0.001), while the combination of melittin (10 μg/mL) + palbociclib (22 μg/mL) significantly decreased cyclin-D1 (P=0.048). Palbociclib (11 μg/mL) increased Nrf2 (P=0.029), but the
combination decreased Nrf2 (P<0.05).When compared to palbociclib alone, the combination approach produced greater suppression of IL-6 levels (P=0.016, P=0.004) and inhibited cell migration with wound expansion at higher doses.

Conclusion: In KYSE-30 cells, the combination treatment with melittin (10 μg/mL) and palbociclib (22 μg/mL) produced a pharmacodynamic potentiation on cell viability, regulation of cell cycle, antioxidant response,
inflammation, and migration, suggesting the need for additional in vivo studies.