Modulation of growth and apoptosis response in PC-3 and LNCAP prostate-cancer cell lines by FAS

Abstract

Upon androgen ablation, androgen-sensitive prostatecancer cells die by apoptosis (programmed cell death) (Isaacs et al., 1992). However, androgen-sensitive tumor cells can become androgen-resistant during the progression of prostate cancer. finally causing the death of patients. Determining the mechanism of the cell death of prostate tumors is a significant issue which could lead to successful therapy of androgenresistant prostate cancer. FasiAPO-1 is a cell-surface protein, a member of the TNF-receptor family, and it potentially induces apoptosis in cells (Itoh et al., 1991). Suda and Nagata (1994) have purified the Fas ligand, which is a member of the TNF family that mediates the cell-death signal by binding to Fas/APO-1, and have isolated its gene . In this study, we examined the expression and potential inducibility of apoptosis by Fas signals in prostate-cancer cell lines and the potential application to tumor therapy. MATERIAL AND METHODS Constntction of Fas expression vectorThe mammalian expression vector pCGAAS (Niwa et al., 1991) was provided by Dr. J. Miyazaki (University of Tokyo). The plasmid pCGAAS deprived of CMV enhancer [pCGAAS-CMV( -)] was obtained by digestion with SalI and SnaBI and blunting with Klenow fragment, followed by separation by agarose-gel electrophoresis, purification with a Gene Clean kit I1 (Funakoshi, Tokyo, Japan) and re-ligation with T4 ligase. Plasmid pBL58-I including human Fas cDNA was provided by Dr. S. Nagata (Osaka Bioscience Institute). A 1.8-kb EcoRI fragment of pBL58-1 including the coding region of human Fas cDNA was transferred into the EcoRI site of pCGAAS-CMV( -), then pCFas22 including human Fas cDNA in the transcribable direction under the control of the chicken p-actin promoter of pCGAAS-CMV(-) was obtained.Transfection of Fas cDNA PC-3 and LNCaP human prostate-cancer cells were first cloned by limiting dilution to avoid clonal heterogeneity of parental tumor cells for transfection. PC-3 and LNCaP cells of a single clone were co-transfected with PstI-digested pCFas22, forming linear DNA, and EcoRI-digested PUC19 inserted with the tyg-neomycin-resistant gene at a 20:l molar ratio by electroporation. As controls, parental PC-3 and LNCaP cells were co-transfected with PstI-digested pCGAAS-CMV( -) and EcoRI-digested PUC19 containing the tyg-neomycin resistance gene. Fas-transfected PC-3 and LNCaP cells as well as control PC-3 and LNCaP cells were cloned with 400 and 800 kg/ml, respectively, of G418 in RPMI-1640 containing 10% FCS, 100 kg/ml of streptomycin and 100 IU/ml of penicillin. Fas/APO-1 expression was confirmed by immunocytochemistry and flow cytometry, as described below. linmunocytochemistry. Cells were cultured in RPMI-1640 containing 10% FCS in 3-cm-diameter flasks containing autoclaved glass cover slips. Cells on cover slips were fixed in 4% formaldehyde in PBS (pH 7.4) for 10 min at room temperature, then in acetone for 3 min at -20°C. The specimens were incubated with 5% normal goat serum for 10 min, then with non-apoptosis-inducible anti-human mo...

Nonviral genetic transfer of Fas ligand induced significant growth suppression and apoptotic tumor cell death in prostate cancer in vivo

“…[24][25][26] Comparing the two delivery vehicles, the PC-3 cells were more effectively transfected by PAMAM dendrimer than by Effectene, whereas Effectene was superior to PAMAM dendrimer as far as LNCaP cells were tested (data not shown). In the following experiments PC-3 and LNCaP cells were transfected by PAMAM dendrimer and Effectene, respectively.…”

“…[24][25][26] Although agonistic anti-Fas antibodies (eg CH-11) also kill Fas-positive tumor cells, 25,26 25 FasL gene transfer may be more effective in inducing apoptosis in PC cells than do anti-Fas antibodies. Membrane-bound FasL (mFasL) is converted into sFasL through enzymatic cleavage by matrix metalloproteinase-like enzymes.…”

“…[21][22][23] Since most PC cells express membrane-bound Fas (mFas) on their surface, FasL gene transfer into PC cells may become a feasible therapeutic approach to this malignancy. [24][25][26] One advantage of FasL gene transfer is that if all the cancer cells are not successfully transfected, the FasLtransfected cells, even if few in number, could induce apoptosis in neighboring cancer cells.…”

β2-microglobulin induces apoptosis in HL-60 human leukemia cell line and its multidrug resistant variants overexpressing MRP1 but lacking Bax or overexpressing P-glycoprotein

“…For example, b 2 m has been shown to be mitogenic to the PC-3 prostate carcinoma cell line and antagonistic to transforming growth factor b1 action (Rawley et al, 1995). While the molecular mechanism of the lack of b 2 m-induced apoptosis in this cell line is unknown, these cells are also resistant to Fas-ligand or TNF-a (Chung et al, 1998;Takeuchi et al, 1996).…”

On the trail of cell death pathways in prostate cancer

“…[3][4][5] The authors of the accompanying report, and others, have shown that prostate cancer cells lines display a wide range of sensitivities to the major ligands which interact with the cognate cell surface receptors, including TNFR1, TRAIL-R1 and TRAIL-R2 and Fas. [6][7][8][9][10] The differences in sensitivity to the ligands has variously been attributed to differences in Bcl-2 levels, 11 differences in IκB and NFκB activation, [12][13][14][15][16] PTEN expression, 17 constitutive activation of the AKT pathway 18 and survivin levels induced through β1-integrin signaling. 19 The authors themselves have previously shown that formation of the TRAIL-DISC in LNCaP cells is androgen dependent.…”