The role of high cell density in the promotion of neuroendocrine transdifferentiation of prostate cancer cells

Abstract

BackgroundTumor heterogeneity and the plasticity of cancer cells present challenges for effective clinical diagnosis and therapy. Such challenges are epitomized by neuroendocrine transdifferentiation (NED) and the emergence of neuroendocrine-like cancer cells in prostate tumors. This phenomenon frequently arises from androgen-depleted prostate adenocarcinoma and is associated with the development of castration-resistant prostate cancer and poor prognosis.ResultsIn this study, we showed that NED was evoked in both androgen receptor (AR)-positive and AR-negative prostate epithelial cell lines by growing the cells to a high density. Androgen depletion and high-density cultivation were both associated with cell cycle arrest and deregulated expression of several cell cycle regulators, such as p27Kip1, members of the cyclin D protein family, and Cdk2. Dual inhibition of Cdk1 and Cdk2 using pharmacological inhibitor or RNAi led to modulation of the cell cycle and promotion of NED. We further demonstrated that the cyclic adenosine 3′, 5′-monophosphate (cAMP)-mediated pathway is activated in the high-density conditions. Importantly, inhibition of cAMP signaling using a specific inhibitor of adenylate cyclase, MDL-12330A, abolished the promotion of NED by high cell density.ConclusionsTaken together, our results imply a new relationship between cell cycle attenuation and promotion of NED and suggest high cell density as a trigger for cAMP signaling that can mediate reversible NED in prostate cancer cells.

Diffusion-weighted endorectal MR imaging at 3T for prostate cancer: correlation with tumor cell density and percentage Gleason pattern on whole mount pathology

“…While TCD is not directly associated with Gleason score, it has been associated with increasing tumor aggressiveness and neuroendocrine differentiation (36, 37). Given the relationship between quantitative ADC parameters, Gleason score and TCD use of these measurements to prospectively triage men into a lower or higher risk category for cancer recurrence/progression based principally on the pre-prostatectomy mpMRI results should be further explored.…”

Differentiation and cell density upregulate cytochrome c levels in megakaryoblastic cell lines: Implications for analysis of CYCS-associated thrombocytopenia

“…Cytochrome c expression increased in SET-2, MEG-01 and U937 cells but not HeLa cells as cell density increased. While high cell density has been reported to induce neuroendocrine transdifferentiation of prostate cancer cells, osteogenic and chondrogenic differentiation of human mesenchymal stem cells, and keratinocyte differentiation [ 37 – 40 ], expression of the differentiation markers CD41 and CD61 on SET-2 or MEG-01 cells did not increase as cell density increased. The upregulation of cytochrome c levels is unlikely to be due to a general increase in the levels of the mitochondrial respiratory chain complexes associated with mitochondrial biogenesis as there was no change in the expression of cytochrome c oxidase subunit II or peroxiredoxin 3.…”

Opposite regulation of MDM2 and MDMX expression in acquisition of mesenchymal phenotype in benign and cancer cells

“…Park, Johns Hopkins University, MD, USA. All cells were maintained under standard conditions as described previously [ 4 , 48 ]. The AmpFLSTR® Identifiler® PCR Amplification Kit (Life Technologies) was used to verify the origin of cell lines.…”

“…Total RNA was isolated using a High Pure RNA Isolation Kit (Roche) and equal amounts of RNA were reverse transcribed using a High Capacity RNA-to-cDNA Kit (Life Technologies). Quantitative RT-PCR was carried out as described previously [ 48 ] using TaqMan assays with primers and conditions specified in Supplementary Table S3 . Relative changes in gene expression were calculated using the E-method based on real efficiency values obtained from calibration curves [ 53 , 54 ].…”