PMC

Chemical structure of (A) chloramphenicol, (B) chloramphenicol inactivated following acetylation, and (C) chloramphenicol inactivated following nitro reduction. (D) Products of step-wise chloramphenicol reduction, from left to right: chloramphenicol, nitroso-chloramphenicol, hydroxylamine-chloramphenicol, and amino-chloramphenicol.

CPL: chloramphenicol; Comb: combination; Comb 1: 0.781 μg/mL of mallotojaponin B and 1.95 μg/mL of chloramphenicol; Comb 2: 0.781 μg/mL of mallotojaponin B and 7.812 μg/mL of chloramphenicol; Comb 3: 1.562 μg/mL of mallotojaponin B and 3.9 μg/mL of chloramphenicol; Comb 4: 0.781 μg/mL of mallotojaponin B and 15.625 μg/mL of chloramphenicol; Comb 5: 0.781 μg/mL of mallotojaponin B and 31.25 μg/mL of chloramphenicol; Comb 6: 3.125 μg/mL of mallotojaponin B and 3.9 μg/mL of chloramphenicol; PODO: Podophyllotoxin; For the same cell lines, bars with the same letter show that there is no significant difference between the different treatments at p ≤0.05.

NMR spectra of chloramphenicol propionate ester and chloramphenicol. (A) ¹³C-NMR spectrum of chloramphenicol propionate ester in (CD₃)₂CO; (B) ¹H-NMR spectrum of chloramphenicol propionate ester in (CD₃)₂CO; (C) ¹³C-NMR spectrum of chloramphenicol in (CD₃)₂CO; (D) ¹H-NMR spectrum of chloramphenicol in (CD₃)₂CO.

Chloramphenicol interrupted protein interaction between SENP-1 and HIF-1α and promoted HIF-1α degradation via the autophagy pathway. (A) Representative images of co-immunoprecipitation assays performed with HIF-1α-overexpressing H1299 cells in the presence or absence of chloramphenicol. Whole cell lysates was immunoprecipitated with anti-HIF-1α (left) or anti-SENP-1 (right) antibody, followed by immunoblotting analysis. A protein complex of HIF-1α/SENP-1 was found in the control treatment. Chloramphenicol treatment not only reduced HIF-1α levels in whole lysate, but also inhibited HIF-1α/SENP-1 interaction. (B) Whole lysate of HIF-1α-overexpressing H1299 was prepared and aliquoted (1 mg protein/vial). Before reaction with the captured antibody, one vial of sample was incubated with chloramphenicol (100 μg/mL) at 4 °C for 1 h. Another vial, without chloramphenicol treatment, was used as a control. Then, the co-immunoprecipitation was performed as described previously. The “input” data showed that neither HIF-1α nor SENP-1 protein level was changed in whole lysates, whatever the presence or absence of chloramphenicol treatment. The HIF-1α/SENP-1 protein complex, which was clearly found in lysate without the chloramphenicol treatment, was diminished in lysate with the chloramphenicol treatment. This data provides substantial evidence to support the interaction between HIF-1α and SENP-1 was damaged by chloramphenicol. (C) Bafilomycin A1 inhibited the HIF-1α protein degradation induced by chloramphenicol; however, there was still no generation of the HIF-1α/SENP-1 protein complexes. N = 4.