捕获肿瘤抗原的树突状细胞治疗小鼠膀胱肿瘤

目的：研究捕获肿瘤抗原的树突状细胞（dendritic cells,DC)治疗膀胱肿瘤的可行性。方法：分离小鼠脏树突状细胞,外体经粒－巨细胞集落刺激因子（GM－CSF）活化和放射线来活的肿瘤细胞刺激后（D组）,治疗膀胱肿瘤移植模型,并设立空白对照组（A）,单纯GM－CSF活化的树突状细胞组（B）及灭活肿瘤细胞组（C）。结果：D组特异性T淋巴细胞活性、IL－4及IFN－γ水平明显高于其它组（P＜0．01）;所有小鼠长期无瘤存活（＞100天）而其它组小鼠存活期小于30天（P＜0．001）。结论：捕获肿瘤抗原的树突状细胞治疗膀胱肿瘤具有一定的临床应用前景。     

DBCCR1 mediates death in cultured bladder tumor cells

Chromosome 9, which is often partially or fully reduced to homozygosity in bladder cancer cells, harbors several tumor suppressor loci including deleted in bladder cancer chromosome region 1 (DBCCR1) at 9q32-33. To study DBCCR1 function, stable cell lines, inducible for DBCCR1 expression by tetracycline, were made, but the DBCCR1 protein was not expressed at detectable levels. To understand the fate of DBCCR1-expressing cells, human bladder tumor cells were transiently transfected with an expression vector containing DBCCR1 fused to enhanced green fluorescent protein (EGFP). Initially, DBCCR1-EGFP-expressing cells demonstrated diffuse cytoplasmic green fluorescence with nuclear exclusion patterns. After time, the intensity level of green fluorescence increased and a granular distribution of protein became visible in the cells. At this point, cells rounded up and detached from the tissue culture dish. Cells transfected with a control vector, containing only EGFP, and partial DBCCR1-EGFP fusion constructs did not demonstrate this behavior. DBCCR1-mediated cell death in cultured tumor cells was independent of caspase-3 activation and did not result in detectable DNA strand breaks by TUNEL staining that are hallmarks of the classical apoptotic pathway.     

Invadopodia: specialized tumor cell structures for the focal degradation of the extracellular matrix

Invasive tumor–derived or transformed cells, cultured on a flat extracellular matrix substratum, extend specialized proteolytically active plasma membrane protrusions. These structures, termed invadopodia, are responsible for the focal degradation of the underlying substrate. Considerable progress has been made in recent years towards understanding the basic molecular components and regulatory circuits and the ultrastructural features of invadopodia. This has generated substantial interest in invadopodia as a paradigm to study the complex interactions between the intracellular trafficking, signal transduction and cytoskeleton regulation machineries; hopes are high that they may also represent valid biological targets to help advance the anti–cancer drug discovery process. Current knowledge will be reviewed here with an emphasis on the many open questions in invadopodia biology.     

Multicellular tumor spheroid formation by breast cancer cells isolated from different sites

Fourteen breast cancer lines (8 human, 5 rat, and 1 mouse) have been studied in terms of their ability to form multicellular tumor spheroids (MTS) with the agar-base method. Only 8 of the lines formed MTS in contrast to a 100% efficiency in a series of 11 varied tumors reported in the initial studies with this method. We have compared the lines that do and do not form MTS in terms of a variety of characteristics (e.g., estrogen receptors, time in serial passage, growth in nude mice, etc.), and only one characteristic, the source of the original tumor cells, was predictive of MTS-forming ability. All 8 of the breast cancer lines (and the original 11 lines) that formed MTS had been obtained from solid growths (primaries or metastases), while the 6 breast cancer lines that did not form MTS were all derived from pleural effusions. Similarly, artificial selection for an ascites variant of the MTS-forming rat 13762 adenocarcinoma line produced the 13762-A line, which could no longer form MTS. These results suggest that breast cancer cells derived from pleural effusions are genetically different from the bulk of the tumor cells in solid breast cancer samples, that they are unable to grow in true solid form, and that these differences persist in spite of prolonged propagation in tissue culture.     

Expression of the retinoblastoma gene product in bladder carcinoma cells associates with a low frequency of tumor formation.

Upon inactivation of both alleles of the retinoblastoma gene (RB), individuals develop the intraocular eye tumor, retinoblastoma. The gene encodes a Mr 110,000 phosphorylated nuclear protein that may be involved in regulation of the cell cycle. Besides retinoblastoma, mutations of the gene have been detected in several other types of tumors, including bladder carcinoma. Up to one-third of bladder carcinomas may contain mutations of the RB gene. Introducing the retinoblastoma gene into single retinoblastoma, osteosarcoma, or prostate carcinoma cell lines suppresses their tumorigenicity as assayed in nude mice. We have sought to extend these results by introducing the retinoblastoma gene into multiple bladder carcinoma lines, and analyzing several of the resulting, cloned lines. We have found that inhibition of tumorigenicity, as assayed by tumor growth in nude mice or growth of cells in soft agar, is the only consistent phenotype observed upon re-expression of RB in all bladder carcinoma cells examined. The effect of RB expression on growth and cellular morphology varied depending on the particular parental cell line. We conclude that RB expression generally correlates with reduced tumorigenicity, but not reduced growth rate, in bladder carcinoma cells.     

Intraocular tumor formation of RB reconstituted retinoblastoma cells

It has been reported that replacement of a functional retinoblastoma (RB) gene in RB defective WERI-27 retinoblastoma cells results in complete loss of their tumorigenic potential in nude mice following s.c. injection. We have repeated the identical studies and found that although tumors did not develop s.c., the RB reconstituted cells, either soon after RB virus infection or after long term cultivation, consistently produced tumors when injected intraocularly. These tumor cells, when reestablished in culture, were found to retain a normal RB protein as determined by direct Western blotting and immunocytochemical staining. The tumors, however, occurred with a longer average latency period and with less frequency compared to those produced by the parental RB defective cells. Our results suggest that reintroduction of the RB gene into WERI-27 cells reduces but does not completely suppress their tumorigenic potential. Since retinoblastoma is an eye tumor it also provides further documentation that the use of an orthotopic injection site can be critical when determining the tumorigenicity of a given cell type.     

膀胱肿瘤抗原致敏的树突状细胞诱导T淋巴细胞抗肿瘤效应的研究

目的：研究经膀胱肿瘤抗原致敏后的树突状细胞（Dc）对T淋巴细胞的激活、增殖作用及对T24膀胱肿瘤细胞的抑癌效应。方法：分离健康供血者外周血单个核细胞及T淋巴细胞，联合应用粒／巨噬细胞集落刺激因子（GM—CSF）及白介素-4（IL-4）从单个核细胞中培养出Dc，以人膀胱癌细胞系T24肿瘤细胞裂解物刺激Dc，检测经膀胱肿瘤抗原致敏后的DC对T淋巴细胞的细胞增殖动力学影响并用M1rr显色法测定致敏Dc诱导的T淋巴细胞对T24膀胱肿瘤细胞体外的抗肿瘤效应。结果：膀胱癌细胞裂解物致敏的Dc可诱导T淋巴细胞强烈的增殖反应，与对照组比较具有显著性差异（P〈0．01）；增殖后的T淋巴细胞对T24膀胱肿瘤细胞有明显的细胞毒作用。结论：经膀胱肿瘤抗原致敏的Dc能诱导产生显著的T淋巴细胞增殖，在体外有明显的抑癌效应。     

In vitro antitumor activity of bropirimine against urinary bladder tumor cells

BACKGROUND: Bropirimine is an orally-active immunostimulant that has an antitumor effect on superficial transitional cell carcinoma of the bladder. The mechanism of its antitumor effect has not yet been clarified. MATERIALS AND METHODS: The cytokine-mediated antiproliferative activity of bropirimine was tested against cultured KK-47 and 724 cells using a modified human clonogenic tumor assay. Perpheral blood mononuclear cells (PBMCs) obtained from five healthy volunteers were co-cultured with bropirimine and the levels of various cytokines, including IFN-alpha, gamma, IL-1beta and TNF-alpha in the supernatants, were quantified. RESULTS: Colony formation by both cell lines was directly inhibited by bropirimine in a dose-dependent manner. In co-cultures of bropirimine and PBMCs, the inhibition of colony formation by both cell lines was not enhanced compared with the effect of bropirimine alone. No significant elevation of cytokines was detected in the presence of PBMCs. CONCLUSION: The results obtained suggest that bropirimine is like to have direct antitumor activity rather than a cytokine-mediated antitumor effect.     

Stromal modulation of bladder cancer-initiating cells in a subcutaneous tumor model

The development of new cancer therapeutics would benefit from incorporating efficient tumor models that mimic human disease. We have developed a subcutaneous bladder tumor regeneration system that recapitulates primary human bladder tumor architecture by recombining benign human fetal bladder stromal cells with SW780 bladder carcinoma cells. As a first step, SW780 cells were seeded in ultra low attachment cultures in order to select for sphere-forming cells, the putative cancer stem cell (CSC) phenotype. Spheroids were combined with primary human fetal stromal cells or vehicle control and injected subcutaneously with Matrigel into NSG mice. SW780 bladder tumors that formed in the presence of stroma showed accelerated growth, muscle invasion, epithelial to mesenchymal transition (EMT), decreased differentiation, and greater activation of growth pathways compared to tumors formed in the absence of fetal stroma. Tumors grown with stroma also demonstrated a greater similarity to typical malignant bladder architecture, including the formation of papillary structures. In an effort to determine if cancer cells from primary tumors could form similar structures in vivo using this recombinatorial approach, putative CSCs, sorted based on the CD44⁺CD49f⁺ antigenic profile, were collected and recombined with fetal bladder stromal cells and Matrigel prior to subcutaneous implantation. Retrieved grafts contained tumors that exhibited the same structure as the original primary human tumor. Primary bladder tumor regeneration using human fetal bladder stroma may help elucidate the influences of stroma on tumor growth and development, as well as provide an efficient and accessible system for therapeutic testing.     

The p75(NTR) tumor suppressor induces caspase-mediated apoptosis in bladder tumor cells

p75(NTR) was identified as a tumor and metastasis suppressor that functions in part via induction of apoptosis in tumor cells. To examine p75(NTR)-dependent apoptosis in tumor cells, we demonstrated that a dose-dependent increase in p75(NTR) expression was associated with a concomitant increase in the mitochondrial proapoptotic effector proteins Bad, Bax and Bik and a decrease in the mitochondrial prosurvival effector proteins phospho-Bad, Bcl-2 and Bcl-x(L). Significantly, p75(NTR)-dependent induction of cytochrome c release from the mitochondria occurred during CHX potentiation of apoptosis. Furthermore, p75(NTR) expression largely suppressed expression of IAP-1 and induced cleavage of procaspase-9 and procaspase-7 but not of procaspases 2, 3, 6, 8 and 10. A specific peptide inhibitor of procaspase-9 cleavage also inhibited cleavage of procaspase-7, indicating that caspase-7 is downstream of caspase-9. As end points of apoptosis, we observed p75(NTR)-dependent annexin V binding to the plasma membrane, an indicator of early apoptotic events, and Hoechst staining of DNA nuclear fragmentation, an indicator of late apoptotic events, whereas control tumor cells that lack expression of the p75(NTR) protein did not exhibit either of these apoptotic markers. Together, these results delineate the mitochondria-mediated apoptotic pathway of the p75(NTR) tumor-suppressor gene product.     

Abrogation of the invasion of human bladder tumor cells by using protease inhibitor(s).

It was shown previously that invasive human transitional cell carcinoma cell line EJ, but not the noninvasive RT4 cells, can degrade basement membrane laminin and that the degradation of basement membrane laminin was a result of a redistribution of activated cysteine proteinase cathepsin B to the plasma membrane of the invasive EJ cells. Using a modified Boyden chamber and an artificial basement membrane, it was found first that cysteine proteinase inhibitor E-64 can abolish the ability of the EJ cells to invade through the artificial basement membrane to the underside of the filter. Second, E-64 can prevent the degradation of purified human basement membrane laminin by the plasma membrane fraction of invasive EJ cells. Third, E-64 does not affect the ability of the EJ cells to attach to the extracellular matrix nor is the inhibitory dose toxic to the cells when assayed with trypan-blue dye exclusion. However, E-64 does affect the ability of the EJ cells to respond to autocrine motility factor-induced motility. Finally, in an in vivo model, E-64 was not toxic to the animals tested and may have limited the blood-borne metastatic ability of invasive EJ cells in the treated animals. It was concluded that proteinase cathepsin B may be involved in human bladder tumor invasion, in both extracellular matrix degradation and factor-induced cellular motility, and the authors suggested that the use of inhibitor(s) to cysteine proteinases may limit the invasive potential of human bladder cancer cells.     

Effect of protein kinase C activating tumor promoters on metastases formation by fibrosarcoma cells

The involvement of protein kinase C (PKC) in regulation of cellular properties related to tumor cell invasiveness was tested in a murine methylcholanthrene-induced fibrosarcoma tumor cell model. A metastatic clone (IE7) derived from the T10 fibrosarcoma was found to possess 30 and 90% more cytosolic and membrane-bound PKC, respectively, compared with the IC9 metastatic clone. Intravenous injection of IE7 but not IC9 cells resulted in lung tumor formation. Long-term (3 months) treatment of IE7 cells with 500 ng/ml phorbol 12,13-dibutyrate (PDB) resulted in a 4-fold reduction in total PKC activity and increase in the tumor cell metastatic ability. Short-term (2h) PDB treatment induced cytosol-to-membrane PKC translocation and decreased the IE7 cells' ability to form hematogenous metastases. Treatment of IC9 cells with PDB did not render them metastatic. To test the possible involvement of distinct PKC isoenzymes in the determination of metastatic properties, we stained the cells with appropriate anti-PKC antibodies followed by FACS analysis. IC9 and IE7 cells exhibited similar levels of fluorescent intensity when stained with either anti-PKC alpha or anti-PKC beta antibodies. The relative proportion of PKC alpha and PKC beta was not changed following short-term PDB treatment of cells, but the intensity of staining was reduced 1.5- to 2-fold following long-term PDB treatment of both cell types. The results indicate that phorbol ester-induced alterations in PKC levels and subcellular distribution affect the metastatic ability of tumor cells and suggest that tumor promoting agents that promote induction of primary tumors may also affect tumor spread by regulating hematogenous metastases formation.     

染料木黄酮抑制多柔比星诱导的多药耐药膀胱肿瘤T24细胞增殖的实验研究

 【摘要】　目的　建立膀胱肿瘤T24细胞多药耐药（MDR）模型并鉴定其耐药特性,观察染料木黄酮对多柔比星（ADM）诱导的多药耐药T24（T24／ADM）细胞增殖的影响。方法　体外培养膀胱肿瘤T24细胞,采用ADM浓度梯度诱导,培养出具有稳定MDR表型的T24／ADM耐药细胞株,光镜观察新建细胞株的形态学特点,MTT法检测多种药物对耐药细胞株的增殖活性以及染料木黄酮对T24／ADM细胞增殖的有效作用浓度。结果　用ADM诱导6个月后的T24／ADM细胞形态无明显改变;T24／ADM细胞对多种化疗药物的耐受能力均明显提高,与亲本细胞株T24相比,耐药细胞株T24／ADM对ADM的耐药指数达15.79,对5-氟尿嘧啶、顺铂、环磷酰胺的耐药指数依次为4.68、3.81、5.53。用染料木黄酮作用于T24／ADM细胞后,对T24／ADM细胞的半数抑制浓度为40 μg／ml,质量浓度为20～100 μg／ml的染料木黄酮具有抑制T24／ADM细胞增殖的作用。结论　建立的T24／ADM细胞具有多药耐药性,达到实验要求。质量浓度为20～100 μg／ml的染料木黄酮可部分抑制人类膀胱肿瘤T24／ADM细胞的增殖。     

致敏树突细胞治疗膀胱肿瘤血液细胞毒性T淋巴细胞的变化

目的观察致敏的树突细胞（DC）治疗膀胱肿瘤（BT）后血液细胞毒性T淋巴细胞（CTL）的变化并探讨其机制。方法选取F344大鼠44只，称重后随机分为4组；均采用膀胱灌注N-甲基亚硝基脲（MNU）制成BT；第11周4组分别经皮下注射磷酸缓冲液（PBS）、未致敏DC、肿瘤抗原及致敏DC，每周1次，共4次；实验第15周，经显微镜和流式细胞仪（FCM）检测。结果致敏DC组膀胱重量比其他三组轻（P〈0．05）。致敏DC组BT病理分期低于PBS组和未致敏DC组（P〈0．05）；CD3^＋ T细胞在致敏DC组低于其余三组（P〈0．05）；CTL在致敏DC组高于其余三组（P〈0．001）。结论应用致敏DC经皮下注射治疗大鼠BT可降低肿瘤的病理分期，未致敏DC皮下注射对膀胱肿瘤治疗无效，肿瘤抗原皮下注射对膀胱肿瘤治疗效果欠佳。致敏DC可通过呈递抗原来激活CTL增生而发挥其免疫杀伤作用。     

Galectin-3 inhibits tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by activating Akt in human bladder carcinoma cells

The antiapoptotic molecule galectin-3 was previously shown to regulate CD95, a member of the tumor necrosis factor (TNF) family of proteins in the apoptotic signaling pathway. Here, we question the generality of the phenomenon by studying a different member of this family of proteins [e.g., TNF-related apoptosis-inducing ligand (TRAIL), which induces apoptosis in a wide variety of cancer cells]. Overexpression of galectin-3 in J82 human bladder carcinoma cells rendered them resistant to TRAIL-induced apoptosis, whereas phosphatidylinositol 3-kinase (PI3K) inhibitors (wortmannin and LY-294002) blocked the galectin-3 protecting effect. Because Akt is a major downstream PI3K target reported to play a role in TRAIL-induced apoptosis, we questioned the possible relationship between galectin-3 and Akt. Parental J82 and the control vector-transfected J82 cells (barely detectable galectin-3) exhibit low level of constitutively active Akt, resulting in sensitivity to TRAIL. On the other hand, J82 cells overexpressing galectin-3 cells expressed a high level of constitutively active Akt and were resistant to TRAIL. Moreover, the blockage of TRAIL-induced apoptosis in J82 cells seemed to be mediated by Akt through the inhibition of BID cleavage. These results suggest that galectin-3 involves Akt as a modulator molecule in protecting bladder carcinoma cells from TRAIL-induced apoptosis.     

Chitosan induces apoptosis via caspase-3 activation in bladder tumor cells.

Recently, because of its low toxicity and biological effects, chitosan has been widely used in the medical and pharmaceutical fields, e.g., for nasal or oral delivery of peptide or polar drug delivery. Here, we report a growth-inhibitory effect of chitosan on tumor cells. The growth inhibition was examined by WST-1 colorimetric assay and cell counting. We also observed DNA fragmentation, which is characteristic of apoptosis, and elevated caspase-3-like activity in chitosan-treated cancer cells. The findings suggest that chitosan may have potential value in cancer therapy.