Fig. 1

2′,3′,4′-THC synergizes with E2 to induce transcription with ERα. A Chemical structure of 2′,3′,4′-THC. B U2OS cells cotransfected with ERE-TK-Luc and ERα were treated with increasing concentrations of E2 in the absence and presence of 5 μM 2′,3′,4′-THC for 24 h. The average RLU for the control cells was 2551 and the 2′,3′,4′-THC treated cells was 2650. C U2OS cells cotransfected with NKG2E-TK-Luc and ERα were treated with increasing concentrations of 2′,3′,4′-THC in the absence and presence of 10 nM E2 for 24 h. D U2OS cells cotransfected with NKG2E-TK-Luc and ERα were treated with 10 nM E2 or 100 nM of the other estrogens in the absence and presence of 5 μM 2′,3′,4′-THC for 24 h. E U2OS cells cotransfected with NKG2E-TK-Luc and ERα were treated with 5 μM of each chalcone in the absence or presence of 10 nM E2 for 24 h. Luciferase activity was measured in cellular lysates with a luminometer. RLU is relative light units. Each point in the figures represents the mean of triplicate samples ± SE. C, D The asterisks indicate statistical significance between the two groups analyzed by t-test. E The asterisks over the bars indicate the significant difference between E2 alone and E2 in combination with the chalcone as analyzed by t-test