ObjectiveTo explore the expression of pituitary tumor transforming gene 1 (PTTG1) during the transformation of prostate cancer from androgen-dependent (ADPC) to androgen-independent (AIPC).

METHODSWe established an AIPC cell model LNCaP-AI by culturing the androgen-dependent LNCaP cell line in the hormone-deprived medium for over 3 months. The cell model was verified and the PTTG1 expression in the LNCaP cells was detected by Western blot and RT-PCR during hormone deprivation.

RESULTSThe AIPC cell model LNCaP-AI was successfully established. The PTTG1 expression was gradually increased in the LNCaP cells with the prolonged time of hormone deprivation and the expressions of matrix metalloproteinases MMP-2 and -9 were elevated at the same time.

CONCLUSIONSThe expression of PTTG1 is increased gradually in AIPC, which may be a target of gene therapy for advanced prostate cancer.

Blotting, Western ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Neoplasms, Hormone-Dependent ; Prostatic Neoplasms ; enzymology ; genetics ; Securin ; genetics

Objective: To investigate the effects of down-regulation of PTTG1 expression on the proliferation, invasiveness and apoptosis of androgen-independent human prostate cancer LNCaP-AI cells and their sensitivity to androgen antagonists. METHODS: Human prostate cancer LNCaP-AI cells were transfected with siRNA targeting the PTTG1 gene using the Lipofectamine 2000 transfection reagent. The proliferation, invasiveness and apoptosis of the cells were detected by MTT, Transwell assay and flow cytometry, respectively. The protein expressions of PTTG1, p-Akt, and p-ERK were determined by Western blot and the mRNA expression of PTTG1 measured by agarose gel electrophoresis. RESULTS: The siRNA expression vector markedly down-regulated the expression of PTTG1, which effectively suppressed the proliferation of the LNCaP-AI cells, with the inhibition rates of (19.47 ± 2.12), (24.01 ± 2.13) and (48.02 ± 2.22)% at 24, 48 and 72 hours, respectively, after transfection, with statistically significant differences among the three groups (P <0.05). The number of the cells passing through the polycarbonate film was remarkably decreased at 24, 48 and 72 hours (74.67 ± 9.85, 56.44 ± 8.66 and 37.33 ± 6.14) as compared with the baseline (111.11 ± 13.47) (P <0.01), while the apoptosis rate of the cells was significantly increased at 24, 48 and 72 hours (18.32 ± 0.94), (19.94 ± 1.30) and (21.73 ± 1.88)% in comparison with the baseline (［2.17 ± 0.49］%)， (P <0.05). PTTG1 siRNA combined with androgen antagonist flumatide exhibited even more significant effects in inhibiting the proliferation and promoting the apoptosis of the LNCaP-AI cells than either used alone, and in a flumatide dose-dependent manner. The inhibition and apoptosis rates of the LNCaP-AI cells treated with 50 nmol/L flumatide were (27.13 ± 3.52) and (3.94 ± 0.48)%, and those treated with siRNA + 50 nmol/L flumatide were (67.51 ± 5.13) and (19.93 ± 1.72)%, respectively, both with statistically significant differences between the two groups (P <0.05). The inhibition and apoptosis rates of the cells treated with 100 nmol/L flumatide were (43.72 ± 3.90) and (5.33 ± 0.66)%, and those treated with siRNA + 100 nmol/L flumatide were (73.19 ± 4.78) and (23.43 ± 1.76)%, respectively, both with statistically significant differences between the two groups (P <0.05). CONCLUSIONS The siRNA expression vector can down-regulate the expression of PTTG1, which can inhibit the proliferation and invasiveness of LNCaP-AI cells, promote their apoptosis, and increase their sensibility to androgen antagonists. Suppressing the expression of PTTG1 may enhance the effect of androgen-deprivation therapy on advanced prostate cancer.
Androgen Antagonists ; pharmacology ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Down-Regulation ; Humans ; Male ; Neoplasm Invasiveness ; Prostatic Neoplasms ; drug therapy ; metabolism ; pathology ; RNA, Small Interfering ; metabolism ; Securin ; genetics ; metabolism ; Time Factors ; Transfection

Objective: To investigate the molecular and signal pathway mechanism of Interleukin-27 affecting the anti-tumor effect of NK92 cells. Methods: NK92 cells were cultured with different concentrations of IL-27 (10, 20, 30 and 60 ng/ml) for 24 hours. The cytotoxicity of NK92 cells to target cells was detected by LDH assay. The expressions of NKG2D, NKp30 and NKp46 on the surface of NK92 cells and the secretion of perforin and granzyme B were detected by Flow cytometry. The expression and phosphorylation level of STATs protein was detected by WB. The DU145 cell transplanted tumor model of prostatic carcinoma in NOD-PrkdcscidIl2rgem1/Smoc mice was established and treated with the combination of NK92 cells and IL-27 to evaluate their anti-tumor efficacy. Results: IL-27 at concentrations of 10, 20 and 30 ng/ml could significantly increase the cytotoxicity of NK92 cells to target cells, and 30 ng/ml exerted the best effect (P<0.05 or P<0.01). 30 ng/ml IL-27 could significantly promote the expressions of NKG2D, NKp30 and NKp46 on surface of NK92 cells, as well as elevate the secretion of perforin (all P<0.05), but didn’t affect the secretion of granzyme B (P>0.05); moreover, it also up-regulated the phosphorylation of STAT1, STAT3 and STAT5 protein (all P<0.01). The combined treatment of IL-27 and NK92 cells obviously extended the survival time of tumor-bearing mice (P<0.05). Conclusions: IL-27 can promote the cytotoxicity of NK92 cells against solid tumor cells and blood tumor cells by promoting expressions of NKG2D, NKp30 and NKp46 on the surface of NK92 cells and the secretion of perforin, which might be related with the phosphorylation of STAT1, STAT3 and STAT5 in JAKSTAT pathway.