Tissue distribution, antitumour activity and in vivo apoptosis induction by MEN10755 in nude mice

MEN10755 is a disaccharide analogue of doxorubicin (DXR) endowed with a broader spectrum of activity compared with DXR in a panel of human tumour xenografts. In an attempt to investigate the pharmacological basis of the improvement of therapeutic efficacy of the analogue, a comparative pharmacokinetic (tissue and tumour distribution) and pharmacodynamic (antitumoral activity and ability to induce apoptosis) study of MEN10755 and DXR was performed in athymic nude mice bearing a human ovarian carcinoma xenograft (A2780). Drug level was quantified by high performance liquid chromatography (HPLC) with fluorimetric detection after a single intravenous (i.v.) injection of 7 mg/kg of MEN10755 or DXR. The results indicated a reduced accumulation of MEN10755 compared with DXR in all tissues investigated (tumour, heart, kidney and liver). The reduction was more marked in normal than tumour tissues. Moreover, in spite of the reduced drug uptake by tumour tissues, the new disaccharide anthracycline given in its optimal regimen showed an enhanced antitumour efficacy, compared with DXR. The drug effects on tumour growth paralleled a marked activation of apoptosis. In conclusion, the pattern of tissue distribution and the pharmacokinetic behaviour were consistent with a better tolerability of the novel analogue which allowed a higher cumulative dose to be delivered. The superior therapeutic efficacy of the analogue over DXR, in spite of a reduced tumour accumulation, supports an increased tumour selectivity.     

In vivo potentiation of radiation response by topotecan in human rhabdomyosarcoma xenografted into nude mice.

The lack of new highly efficacious drugs for cancer treatment promotes the search for innovative therapeutic modalities. The authors reported the results leading to the definition of parameters needed to demonstrate a possible radiopotentiation by topotecan (TPT) on two representative human rhabdomyosarcomas (RMSs) xenografted into nude mice. Experimental studies of radiopotentiation with different doses of topotecan showed that concomitant association of topotecan and RT for 5 consecutive days provided a synergistic therapeutic effect. Response rates were statistically higher with the radiochemotherapeutic combination (P < 0.001). Efficacy enhancement factors of this combination compared with the sum of the antitumoral activity of these treatments separately administrated were 1.54 and 1.60, respectively, on both rhabdomyosarcomas. Moreover, the efficiency of the combination of radiotherapy at the dose of 20 Gy with topotecan (12.5 mg/kg) was not statistically different from that of radiotherapy at the dose of 40 Gy. According to microscopy results, the analyses performed at different periods after topotecan treatment alone, radiotherapy alone, and their combination seemed to show that tumoral repopulation by malignant cells is as fast as the dose of radiotherapy and/or topotecan is low. Furthermore, lesions observed with the dose of 40 Gy were similar to those obtained with the association of topotecan at the dose of 12.5 mg/kg and radiotherapy at the dose of 20 Gy. In conclusion, all clinical and pathological results are consistent with a radiopotentiation effect of topotecan on the two xenografted human rhabdomyosarcomas and are currently leading to the design of clinical studies.     

In vivo activation of nude mouse macrophages by human melanoma cells

Human melanoma cell lines inoculated ip in outbred nude mice were found to activate locally macrophages, which became tumoricidal for the EL 4 target cells in a 48-hour [3H]thymidine cytotoxicity assay. However, the kinetics of this activation largely depended on the tumorigenicity of the cell line used. One week after inoculation with a poorly tumorigenic cell line (PTCL), peritoneal macrophages showed a maximal tumoricidal activity, which then slowly declined to disappear on the 4th week. Macrophages obtained after inoculation of a highly tumorigenic cell line (HTCL) were also activated, but the level of their tumoricidal activity was somewhat lower and decreased more rapidly. Irradiated melanoma cells were also able to activate peritoneal macrophages. The inoculation of a higher number of melanoma cells (less than or equal to 8 X 10(7) cells) resulted in a parallel increase in the cytotoxicity of peritoneal macrophages when activated by PTCL and in a parallel decrease when activated by HTCL. Activated macrophages taken 1 week after tumor cell inoculation and further kept in vitro without additional stimulation progressively lost their tumoricidal activity, within 48 hours after being harvested from PTCL-inoculated mice and within 24 hours after being collected from HTCL-inoculated animals. These data allied to the in vivo capacity of peritoneal cells rich in activated macrophages to prevent the growth of HTCL in nude mice strongly leaned toward the idea that macrophages are involved in the tumor growth control in the absence of a specific immune response. In addition, tumor-macrophage interactions are likely to vary from tumor to tumor and may contribute to the expression of the xenografting capacity of human tumor cells.     

In vitro antitumour activity of resveratrol in human melanoma cells sensitive or resistant to temozolomide

Resveratrol, a polyphenol present in many plant species, exhibits a wide range of biological and pharmacological activities both in vitro and in vivo. It has been shown to exert a potent chemopreventive effect in carcinogenesis models and to induce cell growth inhibition and apoptosis in human tumour cells, including melanoma cells. Malignant melanoma is considered to be a chemotherapy-refractory tumour, and the commonly used anticancer drugs do not seem to modify the prognosis of metastatic disease. To further evaluate the therapeutic potential of resveratrol in the treatment of melanoma, we selected three human melanoma cell lines with different levels of resistance to temozolomide (TMZ), an antitumour triazene compound. The cell lines were subjected to resveratrol treatment and analysed for cell growth inhibition, cell cycle perturbation and apoptosis induction. We found that resveratrol markedly impaired proliferation of both the TMZ-sensitive M14 and the TMZ-resistant SK-Mel-28 and PR-Mel cell lines. The latter cell line was two-fold more resistant to the drug than M14 and SK-Mel-28 cells. The sensitivity of normal human keratinocytes to resveratrol was found to be significantly higher than that of M14 and SK-Mel-28 cells and similar to that of the PR-Mel cell line. This suggests a possible good in vivo therapeutic index for resveratrol. Our results also show that the growth-inhibitory effect of resveratrol on melanoma cells is mainly due to its ability to induce S-phase arrest and apoptosis. Taken together, our data indicate that resveratrol is an interesting candidate for the treatment of advanced melanoma.     

Substituted titanocenes induce caspase-dependent apoptosis in human epidermoid carcinoma cells in vitro and exhibit antitumour activity in vivo

Titanocene compounds are a novel series of agents that exhibit cytotoxic effects in a variety of human cancer cells in vitro and in vivo. In this study, the antiproliferative activity of two titanocenes (Titanocenes X and Y) was evaluated in human epidermoid cancer cells in vitro. Titanocenes X and Y induce apoptotic cell death in epidermoid cancer cells, with IC50 values that are comparable to cisplatin. Characterisation of the cell death pathway induced by titanocene compounds in A431 cells revealed that apoptosis is preceded by cell cycle arrest and the inhibition of cell proliferation. The induction of apoptosis is dependent on the activation of caspase-3 and -7 but not caspase-8. Furthermore, the antitumour activity of Titanocene Y was tested in an A431 xenograft model of epidermoid cancer. Results indicate that Titanocene Y significantly reduced the growth of A431 xenografts with an antitumour effect similar to cisplatin. These results suggest that titanocenes represent a novel series of promising antitumour agents.     

In vitro and in vivo induction of antiangiogenic activity by plasminogen activators and captopril

BACKGROUND: Many antiangiogenic molecules are proteolytically cleaved from larger plasma proteins. For example, plasminogen activators cleave plasminogen into plasmin, and plasmin is converted into angiostatin in the presence of sulfhydryl donors. We thus investigated whether the antiangiogenic activity in plasma could be increased by treatment with recombinant tissue plasminogen activator (rt-PA) and the sulfhydryl donor captopril. METHODS: Human plasma was treated with rt-PA (10 micro g/mL) and/or captopril (1 micro M). Angiogenesis was measured in vitro by human endothelial cell tube formation and endothelial cell proliferation and in vivo in mice with the Matrigel plug assay. Angiostatin was removed from treated plasma by affinity chromatography, immunoprecipitation, or ion-exchange chromatography, and the antiangiogenic activity of the depleted plasma was assessed by tube formation. Three cancer patients were treated with rt-PA and captopril, and their pretreatment and post-treatment plasmas were tested for antiangiogenic activity in vitro. Results: Angiogenesis in vitro was stimulated by untreated plasma and inhibited by plasma that had been treated with rt-PA and captopril but was not affected by treatment with rt-PA and/or captopril alone. In vivo angiogenesis in Matrigel plugs was substantially lower in mice treated with rt-PA and captopril than in untreated control mice. Antiangiogenic activity in treated plasma was largely retained after angiostatin was removed: treated plasma inhibited angiogenesis by 64.3% (95% confidence interval [CI] = 46.4% to 82.2%), relative to untreated plasma, and treated plasma depleted of angiostatin by affinity chromatography or immunoprecipitation inhibited angiogenesis by 65.1% (95% CI = 53.8% to 76.4%) or 63.7% (95% CI = 50.9% to 76.5%), respectively. Antiangiogenic activity of plasma from three cancer patients was higher after treatment with rt-PA and captopril than before such treatment. CONCLUSION: Treatment with rt-PA and captopril induced antiangiogenic activity in vitro and in vivo that appears to be independent of angiostatin.     

In vitro and in vivo induction of human LoVo cells into apoptotic process by non-invasive microwave treatment: a potentially novel approach for physical therapy of human colorectal cancer

The human LoVo and WI-38 cells were exposed to high power non-invasive microwaves. The apoptotic effect of the microwaves on the cells was examined with TUNEL, DNA fragmentation and flow cytometry. The human colon cancer LoVo cells showed pathological change of apoptosis but the normal human WI-38 cells showed no detectable apoptotic response. Exposure of the mice bearing tumor tissue to microwave resulted in a significant regression of the tumor tissue in the animal models. We demonstrate that the LoVo cells can be induced into apoptosis by microwave treatment both in in vitro and in vivo. The data described in this communication implies the possibility that microwave therapy may become a novel approach in human colorectal cancer treatment.     

FR901228 induces tumor regression associated with induction of Fas ligand and activation of Fas signaling in human osteosarcoma cells

We investigated the antitumor effects of FR901228, a HDAC inhibitor, on human osteosarcoma cells, in vitro and in vivo to explore its possible utility in the treatment of pediatric bone cancers. FR901228 caused marked growth inhibition with a 50% inhibitory concentration of 1.2-7.3 nM and induction of apoptosis in all eight osteosarcoma cell lines tested. These effects of FR901228 were also observed in vivo xenograft models on BALB/c nude mice, and treatment with 5.6 mg/kg/day resulting in a >70% reduction in the mean final tumor volume compared with the mean initial tumor volume. TUNEL assays demonstrated extensive apoptosis in tumor sections of mice treated with FR901228. Induction of apoptosis was preceded by increased expression of Fas ligand (FasL) mRNA, resulting in expression of membrane-bound FasL, which was followed by sequential activation of caspase-8 and -3. The level of apoptosis induction was reduced using a neutralizing anti-FasL antibody and overexpression of either the dominant-negative FADD or the viral FLICE inhibitory protein. Furthermore, treatment with a suboptimal dose of FR901228 greatly sensitized osteosarcoma cells to agonistic anti-Fas antibody-mediated apoptosis. These findings suggest that FR901228 is a highly promising antitumor agent against osteosarcoma, inducing apoptosis by the activation of the Fas/FasL system.     

Antiproliferative effect of methyl-beta-cyclodextrin in vitro and in human tumour xenografted athymic nude mice.

The anti-tumour activity of methyl-beta-cyclodextrin (MEBCD), a cyclic oligosaccharide known for its interaction with the plasma membrane, was investigated in vitro and in vivo and compared with that of doxorubicin (DOX) in the human tumour models MCF7 breast carcinoma and A2780 ovarian carcinoma. In vitro proliferation was assessed using the MTT assay. In vivo studies were carried out using xenografted Swiss nude mice injected weekly i.p. with MEBCD at 300 or 800 mg kg(-1) or DOX at 2 mg kg(-1), during 2 months. Under these conditions, MEBCD was active against MCF7 and A2780 cell lines and tumour xenografts. For each tumour model, the tumoral volume of the xenografted mice treated with MEBCD was at least twofold reduced compared with the control group. In the MCF7 model, MEBCD (800 mg kg(-1)) was more active than DOX (2 mg kg(-1)). After 56 days of treatment with MEBCD, no toxicologically meaningful differences were observed in macroscopic and microscopic parameters compared with controls. The accumulation of MEBCD in normal and tumour tissues was also assessed using a chromatographic method. Results indicated that after a single injection of MEBCD, tumour, liver and kidneys accumulated the highest concentrations of MEBCD. These results provided a basis for the potential therapeutic application of MEBCD in cancer therapy.     

In vitro and in vivo susceptibility of human leukemic cells to lymphokine activated killer activity

The susceptibility of human myeloid and lymphoid leukemic blasts to the lytic action of recombinant interleukin-2 (rIL-2)-generated lymphokine activated killer (LAK) cells was analyzed. With the exception of the K562 cell line, all 9 leukemic cell lines tested were resistant to the natural killer activity of freshly isolated peripheral blood lymphocytes (PBL) from healthy donors but were susceptible to the lytic action of PBL cultured for 3 days in the presence of rIL-2. Of the 32 primary myeloid and lymphoid acute leukemia samples investigated, the great majority were natural killer cell-resistant but were variably sensitive to LAK effectors. Variations in LAK activity were observed according to the donor of PBL, while little or no difference was documented in the capacity to elicit LAK activity of PBL cultured with 100 or 1,000 U of rIL-2/ml. Pretreatment of the leukemic target cells with neuraminidase did not increase substantially their sensitivity to LAK activity. LAK cells generated from the PBL of patients at the onset of the disease or in complete clinicohematological remission lysed Raji cells as efficiently as normal LAK effectors. Finally, LAK cells were capable of abrogating the tumor growth in nude mice of a human leukemic T cell line. These findings demonstrate the susceptibility in vitro and in vivo of human leukemic blasts to the lytic effect of LAK cells and point to a possible clinical exploitment of this new form of adoptive immunotherapy in the management of acute leukemia.     

Combination effects of etoposide with other antitumor drugs in vitro and in vivo

Combination effects of etoposide (ET) with each of 10 antitumor drugs were examined with P 388 leukemia cells in vitro and in vivo. Median effect analysis was applied for the evaluation of in vitro effect by the growth inhibition, and the in vivo effect by comparison of the increase of life span (ILS) in a combined group with the sum of ILS's in 2 single agent groups. Among 10 drugs combined with ET, cyclophosphamide (melphalan was used for in vitro study), cisplatin and 6-mercaptopurine exhibited a strong synergism both in vitro and in vivo. The combination of ET with mitomycin C, vincristine, vindesine or cytarabine produced additive or slightly synergistic effect in the both systems. However, methotrexate + ET combination showed an antagonistic effect. Although the combination of ET with doxorubicin or fluorouracil showed a slight synergism in vitro, it was antagonistic in vivo. Thus, the in vitro and in vivo combined effects were consistent in 8 of 10 drugs. The employed methods in the present studies could distinguish high efficacy of ET + cyclophosphamide and ET + cisplatin, which are clinically approved as effective combinations against lung cancer. The methods seem to be useful to assess the drug efficacy in experimental combination.     

Prolonged survival and vascularization of xenografted human glioblastoma cells in the central nervous system of cyclosporine A treated rats

Glioblastoma cells from three established lines were transplanted in oculo and in cerebrum to rat hosts. A very low dose of Cyclosporine A was found sufficient to allow graft survival whereas grafts in non-immunosuppressed animals did not survive. Moderate immunosuppression permitted long term graft survival without aggressive growth of glioblastoma cells, creating a protracted course during which neither cell rejection nor tumor proliferation occurred. A tumor reminiscent of a glioblastoma was only seen in one animal on high immunosuppression. Phenotypic changes such as the induction of glial fibrillary acidic protein (GFAP) production and an astrocytic morphology were observed in the cells growing in oculo but not in cerebrum. Vascularization was easily demonstrated with laminin immunofluorescence but the endothelial proliferation typical of glioblastomas was not seen.     

In vitro and in vivo antitumor activity of lymphokine-induced cytotoxic cells

The present study demonstrates that LICC possess both in vitro and in vivo antitumor activity. The LICC were generated by culturing normal spleen cells with syngeneic peritoneal cells and indomethacin, or with a conditioned medium containing IL 2 with or without a putative new lymphokine, the CCDF. The LICC thus generated selectively killed the lymphoid or solid tumor targets of different H-2 haplotypes and of different etiological origins. The precursors of LICC were probably NK-like cells. The effectors were neither classical NK nor classical cytotoxic T lymphocytes. The LICC were very effective in preventing growth of both lymphoid and solid tumors in vivo, and Thy I+ cells were essential for the anti-tumor effect. The ability to generate LICC was preserved in the tumor-bearing hosts until the terminal stage of tumor growth, when the generation of suppressor T-cells interfered with LICC induction. LICC seem to play an important role in defense against non-immunogenic tumors.     

In vivo and in vitro antitumor activity expressed by cells of concomitantly immune mice

Growth of a primary tumor is often accompanied by the development of resistance to subsequent challenge implants of the same tumor, i.e., concomitant immunity. Using the P815 mastocytoma tumor, the kinetics of concomitant immunity was found to be governed by duration of exposure to the tumor and tumor mass. By implanting small "challenges" prior to the immunizing tumor, resistance to the growth of existing tumor foci was demonstrated. Winn-type assays revealed that antitumor activity was present in cell populations from the peritoneal exudate and lymph node draining the tumor. Peritoneal exudate cells, when infused systemically, were also able to confer protection against P815 mastocytoma challenge, suggesting their role as mediators of concomitant immunity. The 51Cr release technique indicated that cytolytic activity in lymph node cells, peritoneal exudate cells, and the spleen was present over a time course parallel to the kinetics of in vivo challenge. The peritoneal resident cell population was only slightly active; thus, effectors accumulated in the inflammatory exudate. Removal of specific subsets of cells from effector populations with antibody to surface markers and complement produced similar effects on both Winn and cytolytic assays. Anti-Thy 1.2 ablated measurable activity. It was substantially but not completely reduced by anti-Lyt 1.1 and only to a small degree by anti-Lyt 2.1.     

多西紫杉醇联合曲格列酮对人前列腺癌裸鼠移植瘤的抑制作用

目的:探讨多西紫杉醇联合曲格列酮(troglitazone,TGZ)对人前列腺癌裸鼠移植瘤的抑制作用,并初步探索其作用机制.方法:建立人前列腺癌裸鼠移植瘤模型,观察多西紫杉醇联合TGZ对移植瘤生长的抑制作用,FCM法检测移植瘤细胞的凋亡率,免疫组织化学法检测移植瘤组织中bcl-2和bax蛋白的表达情况.结果:与对照组比较, 多西紫杉醇联合TGZ可明显抑制人前列腺癌裸鼠移植瘤的生长,肿瘤体积和质量明显下降,细胞凋亡率明显上升;免疫组织化学法检测结果显示,移植瘤组织中bax蛋白的表达明显增强,bcl-2蛋白的表达明显减弱.结论:多西紫杉醇联合TGZ对前列腺癌有一定的抑制作用,其作用机制可能是通过上调促凋亡蛋白bax的表达及下调抗凋亡蛋白bcl-2的表达,导致肿瘤细胞加速凋亡而实现的.     

Dietary induction of NQO1 increases the antitumour activity of mitomycin C in human colon tumours in vivo

The bioreductive antitumour agent, mitomycin C (MMC), requires activation by reductive enzymes like NAD(P)H:quinone oxidoreductase 1 (NQO1). We used a novel approach to increase MMC efficacy by selectively inducing NQO1 in tumour cells in vivo. CD-1 nude mice were implanted with HCT116 cells, and fed control diet or diet containing 0.3% of the NQO1 inducer, dimethyl fumarate (DMF). The mice were then treated with saline, 2.0, 3.5 or 2.0 mg kg(-1) MMC and dicoumarol, an NQO1 inhibitor. The DMF diet increased NQO1 activity by 2.5-fold in the tumours, but had no effect in marrow cells. Mice given control diet/2.0 mg kg(-1) MMC had tumours with the same volume as control mice; however, mice given DMF diet/2.0 mg kg(-1) MMC had significantly smaller tumours. Tumour volumes in mice given DMF/2.0 mg kg(-1) MMC were similar to those in mice given control diet/3.5 mg kg(-1) MMC. Tumour inhibition was partially reversed in mice given DMF/2.0 mg kg(-1) MMC and dicoumarol. DMF diet/2.0 mg kg(-1) MMC treatment did not increase myelosuppression and did not produce any organ toxicity. These results provide strong evidence that dietary inducers of NQO1 can increase the antitumour activity of bioreductive agents like MMC without increasing toxicity.     

In vivo efficacy of STI571 in xenografted human small cell lung cancer alone or combined with chemotherapy

STI571, or imatinib, selectively inhibits BCR/ABL, PDGFR and c-kit kinase activity. It has been reported that a large proportion of small cell lung cancer (SCLC) cell lines and tumors express c-kit and that STI571 inhibits tumor cell growth. We therefore investigated the therapeutic efficacy of STI571, alone or combined with chemotherapy, in human SCLC cells or tumors xenografted into nude mice. The level of c-kit mRNA expression was variable in SCLC tumors (positive for 2 of 4 xenografts), and c-kit protein was not detected by immunohistochemistry. On the 4 xenografted tumors, PDGFRalpha and PDGFRbeta were not detected by immunohistochemistry. STI571 induced inhibition of proliferation of the SCLC6 cell line without inducing apoptosis; in contrast, in combination with etoposide or topotecan, the growth inhibition of SCLC6 cells induced by STI571 was increased, with apoptotic DNA fragmentation. Four human SCLC xenografts (SCLC6, SCLC61, SCLC74 and SCLC108) were transplanted into mice. After intraperitoneal injection of STI571, we observed 80%, 40% and 78% growth inhibition of SCLC6, SCLC61 and SCLC108 tumors, respectively, without any significant inhibition of SCLC74 tumor growth. In mice bearing responsive SCLC tumors, we observed an increase of growth inhibition induced by chemotherapy (etoposide + ifosfamide or topotecan) by concomitant and continuous administration of STI571, associated with an increase of toxic deaths. In SCLC6-bearing mice receiving sequential treatments, we observed a reduction of toxic deaths but a decrease of synergistic antitumor efficacy. In conclusion, the efficacy of STI571 alone in SCLC xenografted tumors was variable and did not depend on c-kit expression. Moreover, a significant increase of chemotherapy-induced growth inhibition was obtained by concomitant administration of STI571 that should be carefully investigated in SCLC patients.     

Invasive pattern of lac-Z-transfected human glioblastoma cells in nude mice brain

Primary, malignant brain tumors show an extensive infiltrative invasion into surrounding normal brain. At present, little information is available regarding the local invasive behavior of human brain tumors and until now no animal model suitable to mimic human gliomas has been reported. To identify the infiltrative behavior of an established glioblastoma cell line (SNB19), we achieved a stable transfection of the SNB19 cell line with β-galactosidase (lac-Z) plasmid. The stable β-galactosidase-expressing cells were then injected intracerebrally into nude mice in an attempt to follow its pattern of spread. The mice were sacrificed at 3, 4, and 6 weeks postinjection. We could detect tumor formation in all of the animals, and the tumor size increased gradually over the 6 week time period. Three weeks after injection, tumor cells showed characteristic infiltrative invasion along the corpus callosum. We also observed tumor-cell invasion into the anterior commissure in some animals, and each tumor cell could be identified by lac-Z expression as visualized by its blue color. Further invasion was identified at 4 and 6 weeks postinjection. Our results suggest that this model could be used to study the molecular mechanisms involved in the invasion of gliomas so that appropriate therapeutic intervention strategies could be designed.