Farnesyl transferase inhibitors impair chromosomal maintenance in cell lines and human tumors by compromising CENP-E and CENP-F function.
Farnesyl transferase inhibitors (FTI) exhibit anticancer activity as a single agent in preclinical studies and show promise in combination with other therapeutics in clinical trials. Previous studies show that FTIs arrest cancer cells in mitosis; however, the mechanism by which this occurs is unclear. Here, we observed that treatment of various cancer cell lines with the FTI lonafarnib caused mitotic chromosomal alignment defects, leaving cells in a pseudometaphase state, whereby both aligned chromosomes and chromosomes juxtaposed to the spindle poles (termed "lagging chromosomes") were observed in the same cell. To determine how this occurs, we investigated the functionality of two farnesylated mitotic proteins, CENP-E and CENP-F, which mediate chromosomal capture and alignment. The data show that lonafarnib in proliferating cancer cells depletes CENP-E and CENP-F from metaphase but not prometaphase kinetochores. Loss of CENP-E and CENP-F metaphase localization triggered aberrant chromosomal maintenance, causing aligned chromosomes to be prematurely released from the spindle equator and become lagging chromosomes, resulting in a mitotic delay. Furthermore, lonafarnib treatment reduces sister kinetochore tension and activates the BubR1 spindle checkpoint, suggesting that farnesylation of CENP-E and CENP-F is critical for their functionality in maintaining kinetochore-microtubule interactions. Importantly, apparently similar chromosomal alignment defects were observed in head and neck tumors samples from a phase I trial with lonafarnib, providing support that lonafarnib disrupts chromosomal maintenance in human cancers. Lastly, to examine how farnesylation could regulate CENP-E in mediating kinetochore-microtubule attachments, we examined possible docking motifs of a farnesyl group on the outer surface of the microtubule. This analysis revealed three hydrophobic patches on the tubulin dimer for insertion of a farnesyl group, alluding to the possibility of an association between a farnesyl group and the microtubule.
Schafer-Hales
Katherine
K
Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA.
Iaconelli
Jon
J
Snyder
James P
JP
Prussia
Andrew
A
Nettles
James H
JH
El-Naggar
Adel
A
Khuri
Fadlo R
FR
Giannakakou
Paraskevi
P
Marcus
Adam I
AI
D001665:Binding Sites / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D002877:Chromosomes, Human / Q000187:drug effects* / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D051231:Farnesyltranstransferase / Q000037:antagonists & inhibitors*; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018386:Kinetochores / Q000187:drug effects; D008677:Metaphase / Q000187:drug effects; D008840:Microfilament Proteins / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D049468:Prometaphase / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D008941:Spindle Apparatus / Q000187:drug effects; D003986:Dibenzocycloheptenes
D002868:Chromosomal Proteins, Non-Histone; D004791:Enzyme Inhibitors; D051231:Farnesyltranstransferase; D008840:Microfilament Proteins; D010880:Piperidines; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines; C068688:centromere protein E; C094772:centromere protein F; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; C115354:lonafarnib; D003986:Dibenzocycloheptenes