Drug-induced apoptosis in lung cnacer cells is not mediated by the Fas/FasL (CD95/APO1) signaling pathway.

Anticancer drugs exert at least part of their cytotoxic effect by triggering apoptosis. We previously identified chemotherapy-induced apoptosis in lung cancer cells and suggested a role for p53 alternative or complementary pathways in this process. Recently, a role for the Fas/FasL (CD95/Apo1) signaling system in chemotherapy-induced apoptosis was proposed in some cell types. In the present work, the involvement of the Fas/FasL system in drug-induced apoptosis in lung cancer cells was investigated upon exposure to four cytotoxic drugs (cisplatin, gemcitabine, topotecan, and paclitaxel). We assessed the expression of Fas and FasL and the function of the Fas pathway in six lung cancer cell lines (H460, H322, GLC4, GLC4/ADR, H187, and N417). All lung cancer cell lines expressed Fas and FasL at RNA and protein levels, and apoptosis could be induced in four of six cell lines upon exposure to the Fas agonistic monoclonal antibody (mAb) CLB-CD95/15. Nevertheless, after drug exposure, no significant FasL up-regulation was observed, whereas the Fas expression was increased in the wild-type p53 cell line H460, but not in the other lines, proved to be mutant p53 by direct gene sequencing. Moreover, no correlation was observed in lung cancer cell lines between sensitivity to drugs and to a Fas agonistic mAb, and preincubation of cells with either the Fas-antagonistic mAb CLB-CD95/2 or a FasL-neutralizing mAb did not protect from drug-induced apoptosis. Taken together, these observations strongly argue against a role of the Fas/FasL signaling pathway in drug-induced apoptosis in lung cancer cells. Interestingly, caspase-8 activation was observed upon drug exposure, independently from Fas/FasL signaling.     

Ex vivo pediatric brain tumors express Fas (CD95) and FasL (CD95L) and are resistant to apoptosis induction

Fas (APO-1/CD95/TNFRSF6) is a member of the tumor necrosis/nerve growth factor receptor family that signals apoptotic cell death in sensitive cells. Expression of Fas and its agonistic ligand (FasL/TNFSF6) was investigated in ex vivo pediatric brain tumor specimens of various histologic types. Fas expression was identified in all of the 18 tumors analyzed by flow cytometry and immunohistochemistry. FasL expression was identified in most of the 13 tumors analyzed by both Western analysis and immunohistochemistry. Nine of these tumor specimens were treated with either the agonistic anti-Fas antibody (APO-1) in combination with protein A or FasL in short-term cytotoxicity assays. Sensitivity to apoptosis induced by the topoisomerase II inhibitor, etoposide, was also assessed. Despite the presence of Fas, all the specimens analyzed demonstrated a high degree of resistance to Fas-mediated apoptosis. These 9 specimens also showed a high degree of resistance to etoposide. Only 2 of the 9 specimens were susceptible to etoposide-induced cell death, whereas only 3 were sensitive to Fas-mediated apoptosis. One brain tumor was sensitive to both Fas ligation and etoposide treatment. This contrasted with the high degree of susceptibility to both etoposide- and Fas-induced apoptosis observed in the reference Jurkat cell line. The results suggest that Fas expression may be a general feature of tumors of the CNS and that a significant degree of resistance to Fas-mediated apoptosis may exist in ex vivo pediatric brain tumor specimens.     

Physalis peruviana extract induces apoptosis in human Hep G2 cells through CD95/CD95L system and the mitochondrial signaling transduction pathway

Physalis species is a popular folk medicine used for treating cancer, leukemia, hepatitis and other diseases. Studies have shown that the ethanol extract of Physalis peruviana (EEPP) inhibits growth and induces apoptotic death of human Hep G2 cells in culture, whereas proliferation of the mouse BALB/C normal liver cells was not affected. In this study, we performed detailed studies to define the molecular mechanism of EEPP-induced apoptosis in Hep G2 cells. The results further confirmed that EEPP inhibited cell proliferation in a dose- and time-dependent manner. At 50 microg/ml, EEPP significantly increased the accumulation of the sub-G1 peak (hypoploid) and the portion of apoptotic annexin V positive cells. EEPP was found to trigger apoptosis through the release of cytochrome c, Smac/DIABLO and Omi/HtrA2 from mitochondria to cytosol and consequently resulted in caspase-3 activation. Pre-treatment with a general caspase inhibitor (z-VAD-fmk) prevented cytochrome c release. After 48 h of EEPP treatment, the apoptosis of Hep G2 cells was found to associate with an elevated p53, and CD95 and CD95L proteins expression. Furthermore, a marked down-regulation of the expression of the Bcl-2, Bcl-XL and XIAP, and up-regulation of the Bax and Bad proteins were noted. Taken together, the present results suggest that EEPP-induced Hep G2 cell apoptosis was possibly mediated through the CD95/CD95L system and the mitochondrial signaling transduction pathway.     

mHFE7A, a newly identified monoclonal antibody to Fas, induces apoptosis in human melanoma cells in vitro and delays the growth of melanoma xenotransplants

The Fas receptor is a potentially valuable therapeutic target in cancer treatment. However, the clinical application of antibodies directed to this target is hindered by their serious side effects in vivo, including liver toxicity. One murine monoclonal antibody, mHFE7A, binds both to human Fas and murine Fas, without inducing any obvious side effects. However, the potential therapeutic effects of mHFE7A are unclear in human cancer cells or tumors. Here, we determined whether mHFE7A could induce apoptosis in vitro, and assessed its effects on major apoptotic pathways in a human melanoma cell line, MMN9. We also investigated its anti-cancer effects on transplanted melanoma MMN9 tumors in BALB/c nude mice. Treatment of mHFE7A cross-linking with Ig induced cell death similar to CH-11 treatment. Apoptosis induced by mHFE7A was defined by Hoechst 33342 DNA staining and DNA fragmentation assay. Furthermore, mHFE7A-mediated apoptosis was dependent on activation of a caspase signaling cascade involving caspases-8 and -3. Administration of mHFE7A also delayed the growth of melanoma xenografts. Thus, we provide the first evidence that the murine anti-Fas monoclonal antibody, mHFE7A, induces apoptosis of human malignant melanoma cells in vitro and is anti-tumorigenic in vivo.     

Tetrapeptide DEVD-aldehyde or YVAD-chloromethylketone inhibits Fas/Apo-1 (CD95)-mediated apoptosis in renal-cell-cancer cells

The apoptotic machinery has been intensively investigated, and interleukin-l-beta-converting enzyme (ICE) and its homologs directly mediate apoptosis by means of their unique protease activity. Fas/Apol (CD95), a member of the TNF-receptor family, mediates apoptosis by binding to its ligand, which is mainly expressed on lymphocytes. Here, we investigated the expression and function of both molecules in renal-cell cancer (RCC). The expression of Fas was examined in 6 RCC cell lines by immunoblotting and all of them expressed Fas. ICE and CPP32/YAMA were also identified among the cell lines. We earlier examined ACHN cells expressing low levels of BCL-2, as well as KRC/Y cells with high levels of BCL-2. Here, we found that the anti-Fas monoclonal antibody, CH-11, induced apoptosis in a dose-dependent fashion more remarkably in ACHN cells. Pre-incubation with the tetrapeptide YVAD-chloromethylketone or DEVD-aldehyde inhibited Fas-mediated apoptosis. These findings suggest that, in RCC, apoptosis is induced by lymphocytes bearing Fas-L, and that it is achieved through the proteolytic action of CPP32/YAMA and/or ICE, or another member of the ICE/ced-3 protease family. © 1996 Wiley-Liss, Inc.     

Expression of Fas ligand (CD95L) in primary malignant melanoma and melanoma metastases is associated with overall survival

BACKGROUND: There is increasing evidence that the Fas/Fas ligand (FasL) system is involved in tumor-mediated immune suppression. The purpose of this study was to investigate the effect of Fas (CD95) as well as FasL (CD95L) expression in primary malignant melanoma and melanoma metastases on overall survival (OS). PATIENTS AND METHODS: 19 patients with metastatic malignant melanoma who were treated with different dacarbazine (DTIC)-based chemotherapy regimens were included in this study. From each patient, primary melanoma biopsies and biopsies from metastases were histologically evaluated. Immunohistology was performed with antibodies to Fas/CD95 and FasL/CD95L. Differences in OS were plotted using the Kaplan-Meier method and compared by the log rank test. RESULTS: Fas/CD95 and FasL/CD95L expression was detected in 73.7 and 63.2% of primary melanomas, respectively. In metastases, expression of both Fas/CD95 (63.2%) and FasL/CD95L (47.4%) was markedly decreased. Presence of FasL/ CD95L expression in primary melanoma resulted in significantly (p = 0.024) prolonged OS compared with FasL/CD95L-negative high-risk primary melanomas. In contrast, loss of FasL/CD95L expression in melanoma metastases resected before chemotherapy was associated with significantly prolonged median survival (p = 0.0139). CONCLUSION: Presence of FasL/CD95L expression in primary malignant melanoma and the loss of FasL/ CD95L expression in metastases seem to be positive prognostic factors.     

Frequent downregulation of Fas (CD95) expression and function in melanoma

Membrane-bound Fas ligand (FasL, Apo-1L, CD95L) induces rapid apoptosis of Fas (CD95)-sensitive cells on interaction with Fas, and is an important effector molecule of cytolytic T lymphocytes (CTLs). Melanomas are immunogenic and induce the production of specific CTLs, but are usually able to escape immune destruction. We investigated Fas expression and function in 53 cutaneous melanocytic lesions and 13 melanoma cell lines grown in vitro. Immunohistochemical analysis of Fas expression in cutaneous melanocytic lesions showed moderate to high levels of Fas in common benign melanocytic naevi, but low to undetectable levels in atypical naevi, primary (superficial spreading melanoma, nodular melanoma) and cutaneous melanoma metastases. Fluorescence-activated cell sorting (FACS) analysis of Fas expression in melanoma cell lines revealed undetectable or low levels of cell surface Fas expression in five of the 13 melanoma cell lines. Analysis of Fas signalling by quantification of cell death following exposure to recombinant FasL showed that a reduction in Fas expression results in resistance to FasL-mediated cell death. Furthermore, two of the 13 melanoma cell lines were found to be resistant to FasL-mediated cell death despite conserved Fas expression. Thus seven of the 13 melanoma cell lines were found to have impaired Fas signalling. Taken together, our results indicate that downregulation of Fas expression and resistance to Fas-mediated apoptosis are frequent in melanoma.     

Fas (APO-1/CD95) signaling pathway is intact in radioresistant human glioma cells

Radiation-induced apoptosis can be mediated through pathways initiated by either DNA damage or ceramide-induced Fas signaling. Glioblastoma multiforme is a primary brain tumor that is highly resistant to irradiation, and U-87 MG, SF126, and T98G are glioblastoma-derived cell lines that mimic this characteristic. We found that these radioresistant glioma cells are susceptible to Fas-mediated cell death induced by treatment with either anti-Fas antibody or exogenous ceramide. Fas-mediated cell death in these cell lines is p53-independent. These data demonstrate that apoptosis can be induced by ceramide and mediated through the Fas pathway in glioma cells, although high-dose ionizing radiation fails to trigger this pathway.     

Frequency and resistance of CD95 (Fas/Apo-1) gene-transfected tumor cells to CD95-mediated apoptosis by the elimination and methylation of integrated DNA

It is important for more effective gene therapies to clarify the mechanisms by which cDNA integrated into cells can maintain or lose its function in vivo. We evaluated genetic and epigenetic events leading to alternation of the introduced CD95 (Fas/Apo-1) gene as a model of gene therapy. Solid tumors formed by CD95 cDNA-transfected hepatoma cells (F6b) were almost completely cured by a single treatment of anti-CD95 monoclonal antibody (mAb) but recurred in gld/gld lpr/lpr mice after initial complete response. Recurred tumors were resistant to repeated mAb treatment. The ratio of resistant cells in tumors was estimated as 4.2 cells per 10(6) cells. The CD95-resistant tumor contained CD95-vanished and CD95-decreased cells. CD95-vanished cells were due to the deletion of CD95cDNA. However, CD95-decreased cells retained CD95cDNA, which was highly methylated when determined with methylation-dependent enzymes and a demethylation reagent, indicating that DNA methylation was responsible for the reduced CD95 expression and resistance to mAb. CD95-decreased cells reduced the CD95 expression further but did not delete cDNA after a second in vivo treatment with anti-CD95 mAb, suggesting that the elimination of cDNA is not induced after its methylation and that cells containing methylated genes became more resistant by further methylation. Thus, the elimination and methylation of integrated cDNA appear to occur through different mechanisms. Our study of resistant tumor cells, which arose by both mutational and epigenetic modifications of the introduced CD95 plasmid, provides important and fundamental information about the fate of introduced cDNA, augmenting the efficiency of gene therapy.     

Resveratrol enhances the expression of death receptor Fas/CD95 and induces differentiation and apoptosis in anaplastic large-cell lymphoma cells

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a phytoalexin found in grapes and other plants, plays a protective role in human atherosclerosis and carcinogenesis. We examined the effects of resveratrol on the anaplastic large-cell lymphoma (ALCL) cell line SR-786. Resveratrol inhibited growth and induced cellular differentiation, as demonstrated by morphological changes and elevated expression of T cell differentiation markers CD2, CD3, and CD8. Resveratrol also triggered cellular apoptosis, as demonstrated by morphological observations, DNA fragmentation, and cell cycle analyses. Further, the surface expression of the death receptor Fas/CD95 was increased by resveratrol treatment. Our data suggest that resveratrol may have potential therapeutic value for ALCL.     

The proteasome inhibitor PS-341 inhibits growth, induces apoptosis, and overcomes drug resistance in human multiple myeloma cells

Human multiple myeloma (MM) is a presently incurable hematological malignancy, and novel biologically based therapies are urgently needed. Proteasome inhibitors represent a novel potential anticancer therapy. In this study, we demonstrate that the proteasome inhibitor PS-341 directly inhibits proliferation and induces apoptosis of human MM cell lines and freshly isolated patient MM cells; inhibits mitogen-activated protein kinase growth signaling in MM cells; induces apoptosis despite induction of p21 and p27 in both p53 wild-type and p53 mutant MM cells; overcomes drug resistance; adds to the anti-MM activity of dexamethasone; and overcomes the resistance to apoptosis in MM cells conferred by interleukin-6. PS-341 also inhibits the paracrine growth of human MM cells by decreasing their adherence to bone marrow stromal cells (BMSCs) and related nuclear factor kappaB-dependent induction of interleukin-6 secretion in BMSCs, as well as inhibiting proliferation and growth signaling of residual adherent MM cells. These data, therefore, demonstrate that PS-341 both acts directly on MM cells and alters cellular interactions and cytokine secretion in the BM millieu to inhibit tumor cell growth, induce apoptosis, and overcome drug resistance. Given the acceptable animal and human toxicity profile of PS-341, these studies provide the framework for clinical evaluation of PS-341 to improve outcome for patients with this universally fatal hematological malignancy.     

6-Bromoindirubin-3'-oxime inhibits JAK/STAT3 signaling and induces apoptosis of human melanoma cells

STAT3 is persistently activated and contributes to malignant progression in various cancers. Janus activated kinases (JAK) phosphorylate STAT3 in response to stimulation by cytokines or growth factors. The STAT3 signaling pathway has been validated as a promising target for development of anticancer therapeutics. Small-molecule inhibitors of JAK/STAT3 signaling represent potential molecular-targeted cancer therapeutic agents. In this study, we investigated the role of JAK/STAT3 signaling in 6-bromoindirubin-3'-oxime (6BIO)-mediated growth inhibition of human melanoma cells and assessed 6BIO as a potential anticancer drug candidate. We found that 6BIO is a pan-JAK inhibitor that induces apoptosis of human melanoma cells. 6BIO directly inhibited JAK-family kinase activity, both in vitro and in cancer cells. Apoptosis of human melanoma cells induced by 6BIO was associated with reduced phosphorylation of JAKs and STAT3 in both dose- and time-dependent manners. Consistent with inhibition of STAT3 signaling, expression of the antiapoptotic protein Mcl-1 was downregulated. In contrast to the decreased levels of phosphorylation of JAKs and STAT3, phosphorylation levels of the Akt and mitogen-activated protein kinase (MAPK) signaling proteins were not inhibited in cells treated with 6BIO. Importantly, 6BIO suppressed tumor growth in vivo with low toxicity in a mouse xenograft model of melanoma. Taken together, these results show that 6BIO is a novel pan-JAK inhibitor that can selectively inhibit STAT3 signaling and induces tumor cell apoptosis. Our findings support further development of 6BIO as a potential anticancer therapeutic agent that targets JAK/STAT3 signaling in tumor cells.     

Cisplatin (CDDP) sensitizes human osteosarcoma cell to Fas/CD95-mediated apoptosis by down-regulating FLIP-L expression

The mechanisms of escape from Fas/CD95-mediated apoptosis induced by immunosurveillance(NK cells and T cells) in tumor cells are correlated to tumorigenicity. Human osteosarcoma cell MG-63 constitutively expressed cell surface Fas antigen but was resistant to apoptosis by Fas stimulation. However, suboptimal dose of cisplatin(CDDP) could sensitize MG-63 cells to Fas-mediated apoptosis without up-regulation of cell-surface Fas antigen. Western blotting analysis showed that MG-63 cells constitutively expressed FLICE inhibitory protein long form(FLIP-L), which was a novel anti-apoptotic protein and had a potency of tumorigenicity. CDDP down-regulated FLIP-L in a time-dependent manner in MG-63 cells but did not influence expression of other anti-apoptotic molecules such as XIAP, c-IAP-1, c-IAP-2, FADD or pro-caspase-8. Moreover, antisense oligonucleotide to FLIP-L confirmed that down-regulation of FLIP-L induced sensitization to Fas-mediated apoptosis. These findings suggest that FLIP-L contributes to resistance to Fas-mediated apoptosis in MG-63 cells, and sensitization to Fas-mediated apoptosis by CDDP can be a new application of immune therapy.     

穿心莲内酯通过抑制Fas/FasL 信号轴降低子宫内膜癌Ishikawa/DPP 细胞对顺铂的耐药性

目的：探讨穿心莲内酯（Andro）调节脂肪酸合成酶（Fas）/脂肪酸合成酶配体（FasL）信号轴对子宫内膜癌Ishikawa 细胞顺铂（DDP）耐药性的影响。方法：采用0、5、10、20 μg/mL DDP分别处理Ishikawa 细胞和顺铂耐药的Ishikawa/DPP 细胞,0、5、 10、25、50 μmol/L Andro 处理Ishikawa/DDP 细胞,MTT 法检测细胞增殖情况并为后续实验选择合适的给药剂量。将Ishikawa/DDP 细胞随机分为对照组、DDP 组（DDP 干预）、Andro 组（DDP、Andro 干预）、pcDNA3.1-NC 组（转染pcDNA3.1+DDP、Andro 干预）、pcDNA3.1-Fas/FasL 组（转染pcDNA3.1-Fas/FasL+DDP、Andro 干预）,24 h 后,采用qPCR 法检测Fas、FasL mRNA的表达,平板克隆形成实验、Transwell 实验和流式细胞术分别检测细胞克隆能力、细胞迁移与侵袭和细胞凋亡,WB法检测增殖细胞核抗原（PCNA）、BAX、Bcl-2、MMP-2、PD-L1、多药耐药蛋白-1（MDR-1）及Fas、FasL 蛋白表达。结果：DDP 以剂量依赖的方式抑制Ishikawa 和Ishikawa/DPP 细胞增殖,并且与Ishikawa 细胞比较,Ishikawa/DPP 细胞对DDP 的敏感性更低（均P<0.05）;Andro 以剂量依赖性的方式抑制Ishikawa/DPP 细胞的增殖（均P<0.05）。Ishikawa/DPP 细胞中Fas、FasL 的表达水平均高于Ishikawa 细胞（均P<0.05）。选取20 μg/mL DDP 和25 μmol/L Andro 为干预剂量,干预时间24 h。与对照组比较,DDP 组Ishikawa/DPP 细胞中PD-L1、MDR-1、Fas、FasL mRNA及蛋白表达水平显著升高（P<0.05）,而克隆形成率、迁移与侵袭细胞数、凋亡率差异均无统计学意义（均P>0.05）;与DDP组比较,Andro 组Ishikawa/DPP 细胞中Fas、FasL mRNA表达水平、细胞克隆形成率、迁移与侵袭细胞数、 PCNA、Bcl-2、MMP-2、PD-L1、MDR-1、Fas、FasL 蛋白表达水平显著降低,BAX蛋白表达水平及凋亡率显著升高（P<0.05 或P<0.01）, pcDNA3.1-NC 组与Andro 组类似;与pcDNA3.1-NC 组比较,pcDNA3.1-Fas/FasL 组 Ishikawa/DPP 细胞上述指标变化均被逆转（P<0.05）。结论：Andro 可能通过抑制Fas/FasL 信号轴来抑制Ishikawa/DPP 细胞增殖、迁移与侵袭,促进凋亡,从而降低细胞对DDP的耐药性。     

Stimulation of CD40 in human bladder carcinoma cells inhibits anti-FAS/APO-1 (CD95)-induced apoptosis

CD40 and the CD95 (Fas/APO-1 antigen) are both members of the tumor necrosis factor receptor family. Whereas CD40 mediates a strong growth stimulatory signal in B cells, engagement of the CD95 receptor leads to growth inhibition and induction of apoptosis. As it has been reported that CD40 activation may rescue B cells from undergoing apoptosis, we were interested to see whether it had a similar effect in other cells expressing the CD40 receptor. We used epithelial tumor cells from the urinary bladder, a cell type that frequently expresses CD40 but for which no clear function of the molecule has been assigned. We found that the ligation of CD95 with the antibody anti-APO-1 induced apoptosis in most of the cell lines tested. Stimulation of CD40 with antibodies or a soluble construct of the CD40 ligand was shown to protect cells from apoptosis, as demonstrated by their ability to suppress the growth inhibition exerted by the anti-APO-1 antibody. Our results show that CD40 stimulation make cells less vulnerable to apoptosis induced via CD95 and suggest that CD40 expression on epithelial tumors may be associated with cell survival. Int. J. Cancer 77:849–853, 1998.© 1998 Wiley-Liss, Inc.     

L1 adhesion molecule (CD 171) in development and progression of human malignant melanoma

The L1 adhesion molecule (CD171) plays an important role in axon guidance and cell migration in the nervous system. In the human, L1 is expressed on tumors derived from neurocrest and on certain carcinomas. We have analyzed immunohistochemically L1 expression on paraffin embedded specimens of acquired melanocytic nevi, primary cutaneous melanomas, and cutaneous and lymph node metastases of malignant melanomas. We found an increase in L1 immunoreactivity in malignant melanomas and metastases of malignant melanomas as compared to acquired melanocytic nevi that was statistically significant (P<0.05). Additionally, a correlation of L1 immunoreactivity with histological data of prognostic value such as Clark level and the expression of alphav-integrins was found. We detected soluble L1 in the conditioned medium of cultivated melanoma cells but only in 1/40 serum samples from a panel of melanoma patients representing various stages of disease. Our findings suggest that the presence of L1 might contribute to tumor progression by promoting cell adhesion and migration.     

An anti-Wnt-2 monoclonal antibody induces apoptosis in malignant melanoma cells and inhibits tumor growth

Activation of the Wnt/beta-catenin signaling pathway has been associated with human cancers. To test whether Wnt-2 signal is a survival factor in human melanoma cells and thus represents a potential therapeutic target, we investigated the effects of inhibition of Wnt-2 signaling in human melanoma cell lines. We have developed a novel monoclonal antibody against the NH(2) terminus of the human Wnt-2 ligand that induces apoptosis in human melanoma cells overexpressing Wnt-2. Whereas incubation of this antibody with normal cells lacking Wnt-2 expression does not induce apoptosis, Wnt-2 signaling blockade by the ligand-binding antibody is confirmed by down-regulation of Dishevelled and beta-catenin. Wnt-2 small interfering RNA treatment in these cells yielded similar apoptotic effects and downstream changes. Down-regulation of an inhibitor of apoptosis family protein, survivin, was observed in both the Wnt-2 antibody-treated and small interfering RNA-treated melanoma cell lines, suggesting that the antibody induces apoptosis by inactivating survivin. In an in vivo study, this monoclonal anti-Wnt-2 antibody suppresses tumor growth in a xenograft model. These findings suggest that the anti-Wnt-2 monoclonal antibody may be useful for the treatment of patients with malignant melanoma.     

结肠腺癌细胞株Fas／FasL的表达与凋亡的关系

目的研究结肠腺癌细胞株经不同化疗药物诱导后Fas/FasL表达与癌细胞凋亡的关系,探索敏感化疗药物的筛选.方法将顺铂、丝裂霉素、氟尿嘧啶、表阿霉素按PPC(血浆峰浓度)、1/10PPC、1/5PPC、5PPC、10PPC加入结肠腺癌LS174T细胞、LoVo细胞共孵,用流式细胞术(FACScan)检测癌细胞Fas、FasL表达率及细胞凋亡率,并提取DNA进行琼脂糖凝胶电泳.结果FACScan检测显示LS174T细胞顺铂组、丝裂霉素组、表阿霉素组Fas表达率、细胞凋亡率在1/5PPC或PPC时最高,Fas表达率与细胞凋亡率呈正相关(P＜0.05).LoVo细胞经化疗药物诱导后Fas表达率与细胞凋亡率无显著相关(P＜0.05).结论FACScan检测的癌细胞凋亡率可用于敏感化疗药物及其合适剂量的筛选,Fas表达率可能仅适用于部分癌症病人化疗药物的筛选;LS174T细胞与LoVo细胞凋亡途径的不同说明化疗药物的个体化选择研究的重要性.