Combination radiotherapy and cantharidin inhibits lung cancer growth through altering tumor infiltrating lymphocytes

This study aimed to detect the effect of combination radiotherapy and cantharidin on lung cancer growth. We found that combination therapy with radiotherapy and cantharidin was more effective in inhibiting the tumor growth than radiotherapy or cantharidin alone. It decreased the percentage of CD4⁺ Tregs and enhanced the percentage of CD8⁺ T cells, CD4⁺ Teff cells when comparing to that of single treatment. Combination therapy promoted a great increase in double producing CD8⁺ T cells and CD4⁺ Teff cells in tumor infiltrating lymphocytes. Overexpression of CTLA4 reversed the inhibitory action of combination treatment on cancer growth. Our data suggest that combining radiotherapy and cantharidin may have synergistic effects in driving tumor rejection by increasing T-cell infiltration, proliferation and cytokine production.