All of these are G2 phase blockers except:
(A) Etoposide (B) Topotecan (C) Paclitaxel (D) Daunorubicin
(C) Ans: C. Paclitaxel(Ref: Goodman Gilman 121e p1708; Katzung 13/e p932, 12Ie p963; KDT 7/e p865)Paclitaxel:Taxane, which act by causing disruption of the cell's microtubule function by stabilizing microtubule formation.Acts on the M-phase of cell division.Binds specifically to the P-tubulin subunit of microtubules and antagonizes the disassembly of this key cvtoskeletal protein, with the result that bundles of micro-tubules and aberrant structures derived from microtubules appear in the mitotic phase of the cell cycle.Arrest in mitosis follows.