[Changes of intracellular cholesterol metabolism in neuroendocrine differentiation of prostate cancer and their significance].

OBJECTIVE

To explore the roles of intracellular cholesterol metabolism in neuroendocrine (NE) differentiation of prostate cancer based on an androgen-independent prostate cancer NE cell model induced by androgen deprivation.

METHODS

LNCaP cells were cultured in androgen-depleted medium, and NE phenotypes were identified by observing the changes in cell morphology, molecular markers (SgIII, NSE and CgA) and cell proliferation. The expression and distribution of cholesterol and Sg III were determined by immunofluorescence staining. The expressions of the key genes LDL-R, SREBP-1 and SREBP-2 involved in cholesterol synthesis and uptake were detected by semi-quantitative RT-PCR.

RESULTS

The LNCaP cells showed shrinking bodies and extending axons after androgen deprivation, and all the molecular markers, such as Sg III, NSE and CgA, significantly increased in a time-dependent manner, while the cell proliferation was obviously inhibited (P < 0.05). The cholesterol distribution in the LNCaP cells after NE differentiation presented remarkable aggregation at the axon terminals. However, there were no significant differences in the expression of cholesterol between the two types of cells, nor in the changes of the expressions of key genes LDL-R, SREBP-1 and SREBP-2 involved in cholesterol synthesis and uptake (P > 0.05).

CONCLUSION

Transient androgen depletion could successfully induce NE differentiation of LNCaP cells, and the intracellular cholesterol could re-distribute into axon terminals to enhance the formation of neurosecretory granules.