title: Down-regulation of osteopontin attenuates breast tumour progression in vivo.
abstract: Development of breast tumour malignancies results in enhanced expression of various oncogenic molecules. Elevated expression of osteopontin (OPN) in higher grades of breast carcinoma correlates with enhanced expressions of several oncogenic molecules (urokinase-type plasminogen activator [uPA], matrix metalloproteinase-2/-9 [MMP-2 and -9]) and increased angiogenic potential of breast carcinoma. In this study, using in vitro and multiple in vivo models, we have demonstrated that silencing of OPN by its specific small interfering RNA (siRNA) down-regulates the expressions of oncogenic molecules such as uPA, MMP-2 and -9 resulting in inhibition of in vitro cell motility and in vivo tumourigenicity in mice. Moreover our results demonstrated that OPN-/- mice showed slower progression of tumour growth in breast cancer model as compared to wild-type mice. Furthermore, the data showed that injection of carcinogenic compound, pristane (2, 6,10,14-tetramethylpen-tadecane) induces breast tumour progression leading to enhanced expression of OPN and other oncogenic molecules in mammary fat pad of nude- and wild-type mice but not in OPN-/- mice. However, intratumoural injection of OPN siRNA to pristane-induced tumour significantly suppressed these effects. Our data revealed that knocking down of OPN effectively curb breast cancer progression and further suggested that developing of OPN-based therapeutics might be an emerging approach for the next generation of breast cancer management.
authors.affiliation: National Center for Cell Science, Department of Histopathology, YCM Hospital, Pune, India.
authors.forename: Goutam
authors.initials: G
authors.lastname: Chakraborty
authors.forename: Shalini
authors.initials: S
authors.lastname: Jain
authors.forename: Tushar V
authors.initials: TV
authors.lastname: Patil
authors.forename: Gopal C
authors.initials: GC
authors.lastname: Kundu
mesh_terms: D000818:Animals; D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000628:therapy*; D045744:Cell Line, Tumor; D002465:Cell Movement; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D020782:Matrix Metalloproteinases / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D016328:NF-kappa B / Q000235:genetics; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic; D053495:Osteopontin / Q000172:deficiency / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D013729:Terpenes / Q000633:toxicity; D014183:Transplantation, Heterologous; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics; D014841:von Willebrand Factor / Q000235:genetics
chemical_list: D016328:NF-kappa B; D034741:RNA, Small Interfering; C506896:Spp1 protein, mouse; D013729:Terpenes; D014841:von Willebrand Factor; D053495:Osteopontin; C009042:pristane; D014568:Urokinase-Type Plasminogen Activator; D020782:Matrix Metalloproteinases