title: Lycopene enhances docetaxel's effect in castration-resistant prostate cancer associated with insulin-like growth factor I receptor levels.
abstract: Docetaxel is currently the most effective drug for the treatment of castration-resistant prostate cancer (CRPC), but it only extends life by an average of 2 months. Lycopene, an antioxidant phytochemical, has antitumor activity against prostate cancer (PCa) in several models and is generally safe. We present data on the interaction between docetaxel and lycopene in CRPC models. The growth-inhibitory effect of lycopene on PCa cell lines was positively associated with insulin-like growth factor I receptor (IGF-IR) levels. In addition, lycopene treatment enhanced the growth-inhibitory effect of docetaxel more effectively on DU145 cells with IGF-IR high expression than on those PCa cell lines with IGF-IR low expression. In a DU145 xenograft tumor model, docetaxel plus lycopene caused tumor regression, with a 38% increase in antitumor efficacy (P = .047) when compared with docetaxel alone. Lycopene inhibited IGF-IR activation through inhibiting IGF-I stimulation and by increasing the expression and secretion of IGF-BP3. Downstream effects include inhibition of AKT kinase activity and survivin expression, followed by apoptosis. Together, the enhancement of docetaxel's antitumor efficacy by lycopene supplementation justifies further clinical investigation of lycopene and docetaxel combination for CRPC patients. CRPC patients with IGF-IR-overexpressing tumors may be most likely to benefit from this combination.
authors.affiliation: Department of Urology, University of California, Irvine, Orange, CA, USA.
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Tang
authors.forename: Basmina
authors.initials: B
authors.lastname: Parmakhtiar
authors.forename: Anne R
authors.initials: AR
authors.lastname: Simoneau
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.forename: John
authors.initials: J
authors.lastname: Fruehauf
authors.forename: Michael
authors.initials: M
authors.lastname: Lilly
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zi
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols; D000975:Antioxidants / Q000627:therapeutic use*; D017209:Apoptosis / Q000235:genetics; D002338:Carotenoids / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D000077143:Docetaxel; D006801:Humans; D000077276:Lycopene; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000378:metabolism; D043823:Taxoids / Q000627:therapeutic use*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000975:Antioxidants; D043823:Taxoids; D000077143:Docetaxel; D002338:Carotenoids; D017526:Receptor, IGF Type 1; D000077276:Lycopene