Proteomic analysis of zoledronic-acid resistant prostate cancer cells unveils novel pathways characterizing an invasive phenotype

Abstract

Proteomic analysis identified differentially expressed proteins between zoledronic acid-resistant and aggressive DU145R80 prostate cancer (PCa) cells and their parental DU145 cells. Ingenuity Pathway Analysis (IPA) showed a strong relationship between the identified proteins within a network associated with cancer and with homogeneous cellular functions prevalently related with regulation of cell organization, movement and consistent with the smaller and reduced cell-cell contact morphology of DU145R80 cells. The identified proteins correlated in publically available human PCa genomic data with increased tumor expression and aggressiveness. DU145R80 exhibit also a clear increase of alpha-v-(αv) integrin, and of urokinase receptor (uPAR), both included within the same network of the identified proteins. Interestingly, the actin-rich structures localized at the cell periphery of DU145R80 cells are rich of Filamin A, one of the identified proteins and uPAR which, in turn, co-localizes with αv-integrin, in podosomes and/or invadopodia. Notably, the invasive feature of DU145R80 may be prevented by blocking anti-αv antibody. Overall, we unveil a signaling network that physically links the interior of the nucleus via the cytoskeleton to the extracellular matrix and that could dictate PCa aggressiveness suggesting novel potential prognostic markers and therapeutic targets for PCa patients.

Annexin A1 is involved in the acquisition and maintenance of a stem cell-like/aggressive phenotype in prostate cancer cells with acquired resistance to zoledronic acid

“…1-D Western blotting results showed that differently from DU145, DU145R80 cells had undetectable E-cadherin and high vimentin, MMP-2 and MMP-9 expression (Figure 5A ) confirming our previous observations [ 9 , 10 ]. As also reported before, confocal microscopy analyses showed that DU145 cells were characterized by a more epithelial-like morphology: in these cells F-actin staining showed a well organized cytoskeleton with the appearance of several cortical stress fibers (Figure 5B, panel b ; arrows), suggesting a less motile phenotype.…”

“…By using a 2-DE DIGE proteomic approach, we show that ANXA1 is up-regulated in DU145R80 ZA-resistant PCa cells compared with their parental DU145 cells [ 10 ]. Thus, we first evaluated the role of ANXA1 in the maintenance of drug resistance to ZA in DU145R80 PCa cells.…”

“…Preceding analyses performed by Milone et al [ 10 ] showed marked differences in cell morphology between DU145R80 and their parental DU145 cells resulting in a more invasive phenotype of the ZA-resistant sub-line.…”

“…This activation has a critical role in the induction of the resistance, as well as in the acquisition of a more aggressive and invasive phenotype of these cells if compared to their DU145 parental ones [ 9 ]. Moreover, in the ZA chemo-resistant DU145R80 PCa cells we identified a homogeneous group of 15 proteins differently expressed that were associated, for the most part, with regulation of cell morphology, cytoskeletal organization, cell movement and/or cell-to-cell interaction: one of these significantly deregulated proteins was identified as annexin A1 (ANXA1) [ 10 ].…”

Expression and regulation of aldehyde dehydrogenases in prostate cancer

“…In addition to catalysing aldehyde metabolism, ALDH7A1 also plays a role in protecting tissues from the damaging effects of osmotic stress [89] while mutation of the ALDH7A1 gene has been related to pyridoxinedependent epilepsy [90,91] . In cancer, ALDH7A1 is expressed in nodular melanoma (NM) [92] , ovarian [93] and lung cancers [94] while in PCa the isoform has been shown to be involved in intra-bone growth and induced bone metastasis [64] as well as zoledronic acid resistance [95] . Gene expression profiling supports the involvement of ALDH7A1 in multiple molecular pathways related to the metastatic process in PCa [96] .…”