[Prognostic value of PSA kinetics in locally advanced prostate cancer treated by maximal androgen blockade combined with brachytherapy].

OBJECTIVE: To evaluate the effect of post-treatment PSA kinetics on the prognosis of prostate cancer (PCa). METHODS: We retrospectively reviewed the clinical data of 114 cases of locally advanced PCa treated by maximal androgen blockade (MAB) combined with brachytherapy, and analyzed the association of the changes in PSA kinetics with the prognosis of the patients. RESULTS: The median survival time of the patients was 81 (15 - 144) months, with 1-, 3- and 5-year survival rates of 91. 23%, 78.07% and 68.42% , respectively. Univariate analysis indicated that the baseline PSA level, PSA nadir, the time of PSA decreasing to nadir, PSA doubling time, and the extent of PSA declining were all predictive factors for the survival time of the PCa patients. Multivariate analysis demonstrated that PSA nadir, the time of PSA decreasing to nadir, and the extent of PSA declining were three independent prognostic factors, which prolonged the long-term survival of the patients by 1.7, 3.2 and 6.8 times, respectively. CONCLUSION: For locally advanced PCa treated by MAB combined with brachytherapy, PSA nadir <1 micro g/L, the time to nadir <3 months, and the extent of PSA declining >96% are independent prognostic factors.

[Epithelial-mesenchymal transition of prostate cancer: cancer stem cells or bulk cancer cells].

OBJECTIVE: To test the hypothesis that epithelial-mesenchymal transition (EMT) of prostate cancer is most likely to occur in cancer stem cells (CSC). METHODS: The isolation of CSC from LNCaP cell line was performed by flow cytometry based on side-population (SP) phenotype. After SP sorting, LNCaP/SP and LNCaP/NSP were used for further transfection of hypoxia-inducible factor-1α (HIF-1α). Subsequently, EMT-associated proteins were detected by Western blotting. And the assays of Transwell and methyl thiazolyl tetrazolium (MTT) were used to compare invasive and proliferative potency between LNCaP/SP and LNCaP/NSP after HIF-1α induction. Eventually, xenograft experiments were performed with LNCaP/HIF-1α/SP and LNCaP/HIF-1α/NSP cells for further analysis of in vivo tumorigenesis and distant metastasis. RESULTS: Through HIF-1α-induced EMT, LNCaP/HIF-1α/SP exhibited such remarkable EMT characteristics as a positive expression of epithelial markers (E-cadherin and CK18) and a negative expression of mesenchymal markers (vimentin, N-cadherin, fibronectin, cathepsin D, MMP-2 and uPAR). And LNCaP/HIF-1α/NSP underwent partial EMT with an abnormal expression of some mesenchymal proteins (vimentin and cathepsin D) and loss of epithelial protein (CK18) despite reservation of another important epithelial marker (E-cadherin). Further Transwell and MTT assays indicated that LNCaP/HIF-1α/SP exhibited stronger in vitro invasive and proliferative potency than LNCaP/HIF-1α/NSP cells. In animal models, the volume of subcutaneous tumor by LNCaP/HIF-1α/SP cells was much greater than that by LNCaP/HIF-1α/NSP counterparts ((1008 ± 230) vs (288 ± 145) mm(3), P < 0.01). Moreover, LNCaP/HIF-1α/SP cells also had a significantly higher rate of subcutaneous tumor incidence (80% vs 53%, P < 0.05) and bone metastasis (40% vs 0, P < 0.01) as compared with LNCaP/HIF-1α/NSP counterparts. CONCLUSION: As the main target cells of prostatic EMT, CSCs may develop a more malignant phenotype after EMT.

[Long-term outcomes of prostate cancer patients treated with combined brachytherapy and maximal androgen blockade].

OBJECTIVE: To explore the prognostic factors of prostate cancer (PCa) patients and evaluate the effect of brachytherapy on survival time. METHODS: A total of 289 PCa were recruited to collect their clinical and survival data. And their possible prognostic factors were analyzed. A further comparison of 5-year cumulative survival rate was made between the patients treated by maximal androgen blockade (MAB) and those on MAB plus brachytherapy. RESULTS: Their median survival time was 73 (7-144) months. And the 1, 3 and 5-year survival rates were 93.1%, 81.0% and 60.2% respectively. Univariate analysis indicated that prostate volume, basal level of prostate-specific antigen (PSA), Gleason score, tumor stage, PSA nadir, time PSA decreasing to nadir and brachytherapy were all predictive factors for survival time. And multivariate analysis further demonstrated that Gleason score, tumor stage and PSA nadir were independent prognostic indicators. And the combination therapy based on brachytherapy could significantly increase the 5-year cumulative survival rate than MAB-based monotherapy. CONCLUSION: Gleason score, tumor stage and PSA nadir may predict the prognosis of PCa patients. And brachytherapy significantly improves patient survival.

[Sorting and identification of cancer stem cells in human prostate cancer cell lines].

OBJECTIVE: To sort and identify side population (SP) cancer stem cells (CSC) in human prostate cancer (PCa) cell lines. METHODS: Stem-like cells were isolated from five PCa cell lines Du145, IA8, LNCaP, TSU-Pr and PC-3 using FACS based on CD133+ CD44+ immunophenotype and SP in Hoechst staining. The in vitro growth pattern and tumorigenicity of SP stem cells were verified by soft agar colony-formation trial. LNCaP/SP cells were selected for further identification of stem cell properties using immunostaining, proliferation and invasion assay. Eventually, tumorigenicity and metastasis ability of LNCaP/SP were confirmed by xenograft experiments. RESULTS: The percentages of CSCs of the CD133 CD44 + immunophenotype were extremely low in the five PCa cell lines. On the contrary, the percentages of the isolated SP cells were significantly higher in Du145 ([0.15 +/- 0.02]%), IA8 ([0.60 +/- 0.07 ]%), LNCaP ([0.8 +/- 0.1]%) and TSU-PrL ([2.0 +/- 0.4]%), but none was detected in PC-3. Besides, IA8/SP, LNCaP/SP and TSU-PrL/SP cells showed a significantly greater colony-forming efficiency than non-side population (NSP) cells (P < 0.05). Compared with LNCaP/NSP cells, LNCaP/SP cells exhibited high expressions of integrin alpha2, Nanog, CD44, OCT4 and ABCG2, remarkably enhanced invasive and proliferative potentials in vitro, and markedly increased tumorigenicity and metastasis (P < 0.01). CONCLUSION: SP sorting is more suitable than CD133+ CD44+ selection for enriching CSCs from PCa cell lines, and LNCaP/ SP represents a typical CSC population.

[Role of beta-catenin signaling pathway in EMT of human prostate cancer induced by HIF-1alpha].

OBJECTIVE: Epithelial-mesenchymal transition (EMT) is an important process in tumor development. Several studies suggest that the beta-catenin signal pathway may play an important role in EMT. However, there is no direct evidence showing that this pathway actually determines the EMT induced by exogenous signal. Our previous study has successfully proved that over-expression of HIF-1alpha could induce EMT in LNCaP cells, but not in PC-3. So the present study was intended to indicate that the signal of HIF-1alpha for inducing prostate cancer cell to undergo EMT might pass through the beta-catenin pathway. METHODS: Firstly, we analyzed the expression of HIF-1alpha and its target proteins in LNCaP/HIF1alpha and PC-3/HIF1alpha by Western blot. And then EMT-associated proteins were detected by Western blot. Furthermore the potency of invasiveness and proliferation of several cell lines were evaluated by transwell and MTT assay. Lastly the expressions of beta-catenin and GSK-3beta in these cells were analyzed by Western blot and RT-PCR. RESULTS: HIF-1alpha, Glut-1 and VEGF were highly expressed in LNCaP/HIF1alpha and PC-3/HIF1alpha. And PC-3, LNCaP and PC-3/HIF1alpha were EMT-negative cell lines whereas LNCaP/HIF1alpha and IA8 had undergone EMT process. LNCaP/HIF1alpha, IA8 and PC-3/HIF1alpha exhibited a much stronger potency of invasiveness and proliferation than those of PC-3 and LNCaP. The protein levels of total GSK-3beta and phospho-GSK-3beta in LNCaP/HIF1alpha, IA8 and PC-3/HIF1alpha cells significantly decreased; however, the relative ratios of p-GSK3beta/t-GSK3beta increased. Consistently, beta-catenin protein expression increased in LNCaP/HIF1alpha and IA8 cells, but not in PC-3/HIF1alpha; RT-PCR confirmed these results, except for an enhanced transcription activity of beta-catenin mRNA in PC-3/HIF1alpha. CONCLUSION: The activation of the beta-catenin signaling pathway correlates with the characteristic of EMT and potency of invasiveness and proliferation. And it may be one critical factor directly controlling the process of EMT induced by HIF-1alpha in prostate cancer.

[Expressions of E-cadherin and beta-catenin in LNCaP and ARCaP cell lines and their significance].

OBJECTIVE: To observe the expressions of E-cadherin and beta-catenin in LNCaP and ARCaP cell lines and explore their relationship with the metastasis of human prostate cancer. METHODS: The expressions and distribution of E-cadherin and beta-catenin in LNCaP and ARCaP cell lines (IF11 and IA8) were detected by Western blot and immunofluorescent staining. RESULTS: The expression of E-cadherin was high in LNCaP, but absent in IF11 and IA8, while beta-catenin was expressed highly in IF11 and LA8, but lowly in LNCaP. Immunofluorescent staining showed that E-cadherin was mainly in the membrane of LNCaP, while beta-catenin both in the membrane of LNCaP and in the nuclei of IF11 and IA8. CONCLUSION: E-cadherin and beta-catenin are differently expressed and distributed in prostate cancer cell lines with different characteristics of epithelial-mesenchymal transition (EMT), and the abnormal activation of the beta-catenin signal pathway may be involved in the EMT of prostate cancer cells.

[Identification of Wnt/beta-catenin signal pathway in human prostate cancer cell lines and its significance].

OBJECTIVE: To determine the Wnt/beta-catenin signal pathway in different human prostate cancer cell lines and explore its role in epithelial-mesenchymal transition (EMT) in human prostate cancer. METHODS: We detected the expressions of beta-catenin, t-GSK3beta and p-GSK3beta in several prostate cancer cell lines (LNCaP, C4, C4-2, C4-2B, IF11, IA8, PC-3 and DU145) with different characteristics of epithelial-mesenchymal transition (EMT) by Western blotting. RESULTS: There were remarkable differences in the expressions of beta-catenin and p-GSK3beta among the cell lines, with beta-catenin and p-GSK3beta highly expressed in LNCaP, C4, C4-2, C4-2B, IF11 and IA8, lowly expressed in PC-3 and DU145, but no difference was observed in the expressions of t-GSK3beta in all the cell lines. CONCLUSION: There are differences in the state of the Wnt/beta-catenin signal pathway among the cell lines with different characters of EMT.