Thalidomide (5HPP-33) suppresses microtubule dynamics and depolymerizes the microtubule network by binding at the vinblastine binding site on tubulin.
Thalidomides were initially thought to be broad-range drugs specifically for curing insomnia and relieving morning sickness in pregnant women. However, its use was discontinued because of a major drawback of causing teratogenicity. In this study, we found that a thalidomide derivative, 5-hydroxy-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (5HPP-33), inhibited the proliferation of MCF-7 with a half-maximal inhibitory concentration of 4.5 ± 0.4 μM. 5HPP-33 depolymerized microtubules and inhibited the reassembly of cold-depolymerized microtubules in MCF-7 cells. Using time-lapse imaging, the effect of 5HPP-33 on the dynamics of individual microtubules in live MCF-7 cells was analyzed. 5HPP-33 (5 μM) decreased the rates of growth and shortening excursions by 34 and 33%, respectively, and increased the time microtubules spent in the pause state by 92% as compared to that of the vehicle-treated MCF-7 cells. 5HPP-33 (5 μM) reduced the dynamicity of microtubules by 62% compared to the control. 5HPP-33 treatment reduced the distance between the two poles of a bipolar spindle, induced multipolarity in some of the treated cells, and blocked cells at mitosis. In vitro, 5HPP-33 bound to tubulin with a weak affinity. Vinblastine inhibited the binding of 5HPP-33 to tubulin, and 5HPP-33 inhibited the binding of BODIPY FL-vinblastine to tubulin. Further, a molecular docking analysis suggested that 5HPP-33 shares its binding site on tubulin with vinblastine. The results provided significant insight into the antimitotic mechanism of action of 5HPP-33 and also suggest a possible mechanism for the teratogenicity of thalidomides.
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
Aijaz
A
Rashid
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
Annapurna
A
Kuppa
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
Ambarish
A
Kunwar
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
Dulal
D
Panda
D001665:Binding Sites; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D006801:Humans; D054833:Isoindoles / Q000378:metabolism* / Q000494:pharmacology*; D007700:Kinetics; D061986:MCF-7 Cells; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D011247:Pregnancy; D020836:Protein Structure, Quaternary; D059010:Single-Cell Analysis; D013723:Teratogens / Q000378:metabolism / Q000633:toxicity; D013792:Thalidomide / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*; D014747:Vinblastine / Q000378:metabolism*
C501339:2-(2,6-diisopropylphenyl)-5-hydroxy-1H-isoindole-1,3-dione; D054833:Isoindoles; D013723:Teratogens; D014404:Tubulin; D013792:Thalidomide; D014747:Vinblastine