The word centrioles is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 15
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (61 words)
cenotes, centers, centres, cistern, citrons, clients, cloners, coesite, coiners, colters, cornets, coterie, creoles, cretins, cronies, elector, enclose, encores, enteric, enticer, entices, entries, erotics, erotise, estriol, estrone, lectern, lection, lenites, license, lionets, loiters, necrose, norites, nostril, notices, octenes, orients, recites, recline, reclone, reclose, recoils, recoins, relents, relines, reslice, retiles, retinol, roselet, scenter, section, silence, sincere, stencil, sterile, stonier, tensile, toilers, trienes, triones