Epirubicin exhibits potent anti-tumor activity in an animal model of malignant glioma when administered via controlled-release polymers

Epirubicin (EPI) has strong cytotoxic activity that makes it a potential candidate for the treatment of malignant gliomas. To minimize toxicity and increase CNS penetration, EPI was incorporated into biodegradable polymers, and its in vitro and in vivo properties were studied. 9L, F98, C6, U251, and EMT-6 cell lines were treated with EPI in vitro and cell viability was measured. Toxicity of EPI/polycarboxyphenoxypropane-sebacic-acid (pCPP:SA) polymers was tested in vivo using F344 rats intracranially implanted with EPI polymers (2–50% by weight). The efficacy of 50% EPI:pCPP:SA polymers was determined in F344 rats intracranially challenged with 9L and treated either simultaneously or 5 days after tumor implantation. The efficacy of 50% EPI:pCCP:SA polymers administered on Day 5 in combination with oral TMZ was determined in rats intracranially challenged with 9L gliosarcoma. EPI was cytotoxic in all cell lines used in vitro. Intracranial implantation of the EPI polymers in rats generated neither local nor systemic toxicity. Animals receiving intracranial EPI on Day 5 had 50% long-term survivors (LTS), which was superior to local EPI delivered on Day 0 (LTS = 12.5%). Animals receiving intracranial EPI in combination with oral TMZ had 75% LTS whereas no other group had LTS. In those EPI treated animals that died before the controls there was evidence of intracranial hemorrhage. Systemic epirubicin resulted in high toxicity levels and early deaths in all the experiments. EPI polymers, alone or in combination with oral TMZ, is an effective therapeutic modality against experimental 9L gliosarcoma.     

Local Delivery of Minocycline and Systemic BCNU have Synergistic Activity in the Treatment of Intracranial Glioma

Minocycline, a tetracycline derivative, has been shown to inhibit tumor angiogenesis through inhibitory effects on matrix metalloproteinases. Previous studies have shown this agent to be effective against a rodent brain tumor model when delivered intracranially and to potentiate the efficacy of standard chemotherapeutic agents. In the present study, the in vivo efficacy of intracranial minocycline delivered by a biodegradable controlled-release polymer against rat intracranial 9L gliosarcoma was investigated to determine whether it potentiates the effects of systemic 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU). Minocycline was incorporated into the biodegradable polymer polyanhydride poly[bis(p-carboxyphenoxy)propane-sebacic acid] (pCPP:SA) at a ratio of 50:50 by weight. The release kinetics of minocycline from the polymer were assessed. For the efficacy studies, female Fischer 344 rats were implanted with 9L glioma. Treatment with minocycline delivered by the pCPP:SA polymer at the time of tumor implantation resulted in 100% survival in contrast to untreated control animals that died within 21 days. Treatment with the minocycline-polymer 5 days after tumor implantation provided only modest increases in survival. The combination of intracranial minocycline and systemic BCNU extended median survival by 82% compared to BCNU alone (p < 0.0001) and 200% compared to no treatment (p < 0.004). We conclude that local intracranial delivery of minocycline from biodegradable controlled-release polymers inhibits tumor growth and may have clinical utility when combined with a chemotherapeutic agent.     

Polymer Delivery of Camptothecin against 9L Gliosarcoma: Release,Distribution, and Efficacy

Camptothecin is a potent antineoplastic agent that has shown efficacy against multiple tumor lines in vitro; unfortunately, systemic toxicity has limited its in vivo efficacy. This is the first study to investigate the release, biodistribution, and efficacy of camptothecin from a biodegradable polyanhydride polymer. Tritiated camptothecin was incorporated into biodegradable polymers that were implanted intracranially in 16 male Fischer 344 rats and the animals were followed up to 21 days post-implant. A concentration of 11–45g of camptothecin-sodium/mg brain tissue was within a 3mm radius of the polymer disc, with levels of 0.1g at the outermost margin of the rat brain, 7mm from the site of implantation. These tissue concentrations are within the therapeutic ranges for human and rat glioma lines tested against camptothecin-sodium in vitro. The in vivo efficacy of camptothecin-sodium was evaluated with male Fischer 344 rats implanted intracranially with 9L gliosarcoma and compared with the efficacy of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). The animals were divided into four groups. Group 1 (control) had a median survival of 17 days. Group 2 (3.8% BCNU polymer) had a median survival of 23 days (P=0.006). Group 3 (20% camptothecin polymer) had a median survival of 25 days (P=0.023). Group 4 (50% camptothecin polymer) had a median survival of 69 days (P<0.001). Drug loadings of 20% and 50% camptothecin released intact camptothecin for up to 1000h in vitro. We conclude that the biodegradable polymer p(CPP:SA) releases camptothecin-sodium, produces tumoricidal tissue levels, results in little or no systemic toxicity, and prolongs survival in a rat glioma model.     

Plasma and cerebrospinal fluid pharmacokinetics of valproic acid after oral administration in non-human primates

Purpose Valproic acid (VPA), a widely used antiepileptic, also inhibits histone deacetylase (HDAC), and is undergoing evaluation as an anti-cancer agent. We studied the pharmacokinetics of VPA in the plasma and cerebrospinal fluid (CSF) in a non-human primate model that is highly predictive of human CSF penetration to determine if levels of VPA required to inhibit HDAC in in vivo models can be attained. Methods Oral VPA, 75 mg/kg, was administered to four non-human primates. Serial samples of blood (n = 4) and CSF (n = 3) were obtained for pharmacokinetic studies of total and free VPA. Plasma and CSF VPA concentrations were measured using the commercially available Abbott AxSYM VPA assay reagent system (Abbott Laboratories, Abbott Park, IL, USA). The resultant plasma and CSF data were evaluated using pharmacokinetic modeling methods. Results At a dose of 75 mg/kg, the maximum plasma concentration of VPA was 130.1 ± 70.6 μg/ml (mean ± standard deviation) for total drug and 53.3 ± 44.4 μg/ml for free drug. The mean plasma area under the curve (AUC) for total drug was 680 ± 233 μg/ml h and for free drug 146 ± 89 μg/ml hr. The maximum CSF concentration occurred 2–3 h after administration and was 28.2 ± 18.6 μg/ml. The CSF AUC for VPA was 108 ± 52 μg/ml h. The CSF penetration of VPA was 12.9 ± 5.1% for total drug and 57.0 ± 8.7% for free drug. Disappearance from the plasma followed non-linear kinetics with a V _max of 321.2 ± 65.6 μg/kg/min and a K _m of 17.2 ± 13.7 mg/l. Conclusion Valproic acid deserves further study for the treatment of CNS tumors given its high CSF penetration after oral dosing coupled with the anti-tumor activity observed in preclinical studies.     

Effects of bleomycin A5 combined with calmodulin inhibitor on the proliferation of S-180 cellsin vitro

The effects of bleomycin A5 (BLM A5) alone and combined with calmodulin inhibitor N-(4-aminobutyl)-5-chloro-2-naphthalene sulfonamide (W-13) on the proliferation on S-180 cellsin vitro were studied. IC₅₀ of BLM used alone for the cells was about 2.63 μg/ml, but it was reduced to 1/3.8 and 1/9.5 of 2.63 μg/ml when plus W-13 1, 5 μg/ml respectively. The results indicated that nontoxic doses of W-13 enhanced the hinibition of cell proliferation under the condition of BLM 0.5–2.5 μg/ml. In colony forming test, the survival fraction of S-180 cells treated with BLM plus W-13 was decreased to 1/87–240 of that of the cells treated with BLM alone. The results suggest that W-13 can enhance antitumor activity of BLMin vitro and may be used as an synergist of BLM A5in vivo.     

Cisplatin’s tumoricidal effect on human breast carcinoma MCF-7 cells was not attenuated by American ginseng

Purpose We previously observed that American ginseng berry and ginsenoside Re attenuated cisplatin-induced emesis in a rat model, suggesting that the herb may have a value in treating chemotherapy-induced nausea/vomiting. However, it is not clear whether consuming ginseng concurrently with chemotherapy affects the efficacy of chemotherapeutic agents. In this study, we explored if the ginseng extract and its constituents, ginsenosides Rb₁, Rb₃, and Re, alter tumoricidal activity of cisplatin in human cancer cells. Methods Tumoricidal effects of cisplatin, and/or American ginseng berry extract (AGBE) and ginsenosides Rb₁, Rb₃, and Re, on human breast carcinoma MCF-7 cells were measured as cell proliferation in vitro. Cell counts were performed in MCF-7 cells pretreated with test agents for 72 h. Results Cisplatin decreased MCF-7 cell proliferation significantly in a concentration-dependent manner. Compared to control group, cisplatin reduced the cell proliferations to 56.5±3.3% at 1 μg/ml, to 36.6±2.4% at 5 μg/ml, and to 26.9±2.4% at 15 μg/ml (P<0.01). AGBE also inhibited the cell proliferation significantly, although in a less extended manner. When the berry extract at 0.5 mg/ml was used with cisplatin at 1 μg/ml, a significant enhancement of cisplatin’s activity was observed (35.8±2.5%; P<0.05). We also observed that Rb₁ did not change cisplatin’s activity; Rb₃, at a higher concentration, increased cisplatin’s anti-proliferation activity (48.0±1.2%; P<0.05); Re increased cisplatin’s activity (Re 0.1 mg/ml, 48.0±2.8%; Re 0.3 mg/ml, 31.9±2.2%, P<0.01). Conclusion Our data suggest that AGBE and the tested ginsenosides do not attenuate cisplatin’s tumoricidal activity in MCF-7 cells, but in fact may actually enhance it. Additionally, the ginseng extract and ginsenoside Re by themselves exerted anti-proliferative activity against MCF-7 cells. The herb might potentially serve a complementary role with the chemotherapeutic agents in treating cancer, in addition to decreasing chemotherapy-induced nausea/vomiting.     

Activity of the multitargeted antifolate LY231514 in the human tumor cloning assay

Purpose: This study was performed to evaluate the activity of the multitargeted antifolate (MTA or LY231514) against a broad range of human tumors taken directly from patients. Materials and methods: Human tumor colony-forming units were treated with MTA at concentrations of 0.1, 1.0, and 10 μg/ml in 1-h exposure studies. The responses of a limited number of specimens were also evaluated concurrently in 1-h exposures to cisplatin, fluorouracil, irinotecan, and/or paclitaxel. Results: Of 358 specimens plated in the 1-h exposure studies, 148 (41%) were evaluable. Overall, responses were observed in 3% of specimens (4/144) at 0.1 μg/ml, 11% (17/148) at 1.0 μg/ml, and 23% (33/141) at 10 μg/ml. In this range of concentrations achievable clinically, there was a significant concentration-response relationship. At 10 μg/ml in the 1-h exposure studies, the response rate in colorectal cancer specimens was 32% (9/28), and the response rate in non-small-cell lung cancer was 25% (6/24). Responses were also observed in several chemoresistant tumors, including renal cell carcinoma, hepatocellular carcinoma, mesothelioma, and pancreatic carcinoma. The activity of MTA was not completely cross-resistant with that of cisplatin, fluorouracil, irinotecan, and paclitaxel. Conclusions: MTA demonstrated in vitro activity against a spectrum of tumors, including several tumors generally considered chemoresistant. Received: 18 September 1998 / Accepted: 21 December 1998     

Temozolomide treatment does not affect topiramate and oxcarbazepine plasma concentrations in chronically treated patients with brain tumor-related epilepsy

Objective Medical management of brain tumor-related epilepsy is complicated by interactions between antiepileptic and chemotherapeutic drugs. We studied the effect of temozolomide therapy on the disposition of the new antiepileptic drugs topiramate (TPM) or oxcarbazepine (OXC). Methods Fifteen patients chronically treated with TPM or OXC in monotherapy starting a chemotherapeutic treatment with temozolomide were enrolled in the study, of which ten were available for the final analyses. Blood samples were collected before temozolomide treatment (T₀), at its end (T₇) and after further 1–3 weeks (T₁₄–T₂₈). For each patient, more than one treatment cycle was studied. Topiramate and OXC mono-10-hydroxy derivative (MHD) plasma concentrations were determined by hplc coupled with ion spray mass spectrometer (TPM) or ultraviolet (MHD) detection. Results Mean TPM concentrations were 5.4 ± 2.4 μg/ml at T₀ vs. 5.5 ± 2.4 μg/ml at T₇ (n = 14), and 5.4 ± 2.4 μg/ml at T₀ vs. 5.6 ± 2.8 μg/ml at T₁₄–T₂₈ (n = 14). Mean MHD concentrations were 16.4 ± 7.6 μg at T₀ vs. 18.5 ± 9.0 μg/ml at T₇ (n = 5), and 16.8 ± 7.0 μg/ml at T₀ vs. 18.0 ± 8.7 μg/ml at T₁₄–T₂₈ (n = 8) (all comparisons not statistically significant; Student’s t-test for paired samples). Conclusion Temozolomide treatment did not affect TPM plasma concentrations in chronically treated patients. Data for MHD in OXC-treated patients were similar, but, due to the small sample size, results should be interpreted cautiously.These findings confirm that TPM (and possibly OXC) are a reasonable choice of antiepileptic drug in patients with brain tumor-related epilepsy.     

Implantable biodegradable polymers for IUdR radiosensitization of experimental human malignant glioma

Purpose: The potential of halogenated pyrimidines for the radiosensitization of human malignant gliomas remains unrealized. To assess the role of local delivery for radiosensitization, we tested a synthetic, implantablebiodegradable polymer for the controlled release of 5-iodo-2-deoxyuridine (IUdR) both in vitro and in vivo and the resultant radiosensitizationof human malignant glioma xenografts in vivo.Materials and methods: In vitro: To measure release, increasing (10%, 30%, 50%) proportions (weight/weight) of IUdR in the polyanhydride [(poly(bis(p-carboxyphenoxy)-propane) (PCPP) :sebacic acid (SA) (PCPP : SA ratio 20 : 80)] polymer discs were incubated (1 ml phosphate-buffered saline, 37° C). The supernatant fractions were serially assayed using high performance liquid chromatography. To measure modulation of release,polymer discs were co-loaded with 20 Ci 5-125-iodo-2-deoxyuridine (125-IUdR) and increasing (10%, 30%, or 50%) proportions of D-glucose. To test radiosensitization, cells (U251 human malignant glioma) were sequentially exposed to increasing (0 or 10 M) concentrations of IUdR and increasing (0, 2.5, 5.0, or 10 Gy) doses of acute radiation. In vivo: To measure release, PCPP : SA polymerdiscs having 200 Ci 125-IUdR were surgically placed in U251 xenografts (0.1—0.2 cc) growing in the flanksof nude mice. The flanks were reproducibly positioned over a collimated scintillation detector and counted. To measure radiosensitization, PCPP : SApolymer discs having 0% (empty) or 50% IUdR wereplaced in the tumor or contralateral flank. After five days, the tumors were acutely irradiated (500 cGy × 2 daily fractions).Results: In vitro: Intact IUdR was released from the PCPP : SA polymer discs in proportion to the percentage loading. After 4 days the cumulative percentages of loaded IUdR that were released were 43.7 $plusmn; 0.1, 70.0 ± 0.2, and 90.2 ± 0.2 (p < 0.001 ANOVA) for the 10, 30, and 50% loadings. With 0, 10, 30,or 50% D-glucose co-loading, the cumulative release of 125-IUdR from PCPP : SA polymers was 21, 70, 92, or 97%(p < 0.001), respectively, measured 26 days after incubation.IUdR radiosensitized U251 cells in vitro. Cell survival (log₁₀) was – 2.02 ± 0.02 and – 3.68± 0.11 (p < 0.001) after the 10 Gy treatment and no (control) or 10 M IUdR exposures, respectively. In vivo: 125-IUdR Release: The average counts (log₁₀ cpm ± SEM) (hours after implant) were 5.2 ± 0.05 (0.5), 4.3 ± 0.07 (17), 3.9 ± 0.08 (64), and 2.8 ± 0.06 (284). Radiosensitization: Afterintratumoral implantation of empty polymer or intratumoral 50%IUdR polymer, or implantation of 50% IUdR polymers contralateral to tumors, the average growth delays of tumors to4 times the initial volumes were 15.4 ± 1.8, 20.1 + 0.1,and 20.3 + 3.6 (mean + SEM) days, respectively (p = 0.488one-way ANOVA). After empty polymer and radiation treatments,no tumors regressed and the growth delay was 31.1 + 2.1 (p = 0.046 vs. empty polymer alone) days. After implantation of50% IUdR polymers either contralateral to the tumors orinside the tumors, followed by radiation, tumors regressed; growth delays to return to the initial average volumes of 14.0+ 3.6 or 24.2 + 0.2 (p < 0.01) days, respectively.Conclusions: Synthetic, implantable biodegradable polymers hold promise for the controlled release and local delivery ofIUdR for radiosensitization of gliomas.     

Plasma and CSF pharmacokinetics of ganciclovir in nonhuman primates

Purpose: The antiviral nucleoside analogue ganciclovir is a potent inhibitor of replication in herpes viruses and is effective against cytomegalovirus infections in immunocompromised patients. Ganciclovir is also used in cancer gene therapy studies that utilize the herpes simplex virus thymidine kinase gene (HSV-TK). The pharmacokinetics of ganciclovir in adults and children have been described previously but there are no detailed studies of the CNS pharmacology of ganciclovir. We studied the pharmacokinetics of ganciclovir in plasma and CSF in a nonhuman primate model that is highly predictive of the CSF penetration of drugs in humans. Methods: Ganciclovir, 10 mg/kg i.v., was administered over 30 min to three animals. Ganciclovir concentrations in plasma and CSF were measured using reverse-phase HPLC. Results: Peak plasma ganciclovir concentrations ranged from 18.3 to 20.0 μg/ml and the mean plasma AUC was 1075 ± 202 μg/ml · min. Disappearance of ganciclovir from the plasma was biexponential with a distribution half-life (t_1/2α) of 18 ± 7 min and an elimination half-life (t_1/2β) of 109 ± 7 min. Total body clearance (Cl_TB) was 9.4 ± 1.6 ml/min/kg. The mean CSF ganciclovir AUC was 168 ± 83 μg/ml · min and the mean peak CSF concentration was 0.7 ± 0.3 μg/ml. The ratio of the AUCs in CSF and plasma was 15.5 ± 7.1%. Conclusions: Ganciclovir penetrates into the CSF following i.v. administration. This finding will be useful in the design of gene therapy trials involving the HSV-TK gene followed by treatment with ganciclovir in CNS or leptomeningeal tumors. Received: 8 May 1998 / Accepted: 25 September 1998     

Investigation of bioavailability and pharmacokinetics of treosulfan capsules in patients with relapsed ovarian cancer

Purpose: Treosulfan (l-threitol-1,4-bis-methanesulfonate, Ovastat) is a prodrug of a bifunctional alkylating agent with activity in ovarian carcinoma and other solid tumors. In a pharmacologic study of the bioavailability of treosulfan in a capsule formulation, patients with relapsed ovarian carcinoma were treated with alternating doses of oral and intravenous (i.v.) treosulfan of 1.5 or 2.0 g daily for 5 to 8 days. Methods: A sensitive method for the determination of treosulfan in plasma and urine by reversed-phase high-performance liquid chromatography had previously been developed. Pharmacokinetic analyses of treosulfan were carried on plasma and urine samples from 20 i.v. courses and 20 courses of oral administration. Results: The bioavailability ratio (f) of oral to i.v. administration was calculated as 0.97 ± 0.18 (mean ± SD) using the values AUC_oral=82.1 ± 39.4 μg/ml h and AUC_i.v.=85.4 ± 30.3 μg/ml h. The peak plasma concentration c_max (29 ± 14 μg/ml vs 65 ± 23 μg/ml) was significantly (P < 0.01) higher after i.v. administration and the t_max after oral administration was 1.5 ± 0.34 h. The terminal half-life of treosulfan was about 1.8 h. The mean urinary excretion of the parent compound was about 15% of the administered total dose over 24 h (range 6–26%). Conclusions: The high and relatively constant bioavailability of treosulfan indicates that capsules provide a satisfactory noninvasive treatment alternative. A feasible and reliable oral treosulfan formulation could provide the basis for the development of long-term low-dose outpatient treatment of patients with malignant diseases. Received: 28 July 1999 / Accepted: 16 December 1999     

Optimizing interstitial delivery of BCNU from controlled release polymers for the treatment of brain tumors

 Two approaches for improving the interstitial administration of carmustine (BCNU) using 3.8% loaded poly(carboxyphenoxypropane-sebacic acid), an implantable biodegradable anhydride which significantly prolongs survival in patients with recurrent malignant gliomas, were evaluated. First, increasing the ratio of carboxyphenoxypropane (CPP) to sebacic acid (SA) in the polymer increases its hydrolytic stability, thus prolonging its half-life in vivo, and extending the period of drug release. A second approach is to increase the dose of drug loaded into the polymer. This study evaluated the relative merits of these two approaches by comparing release kinetics, safety, and efficacy of escalating BCNU doses in polymers with 20:80 and 50:50 ratios of CPP to SA. At the highest dose tested, the 50:50 polymer released BCNU 2.5 times as long in vitro as the 20:80 polymer. Both formulations were nontoxic in rat brains for all BCNU doses tested except 32%. The 20:80 and 50:50 polymers were equally effective in the rat intracranial 9L-glioma model. A dose-response relationship for BCNU was observed (hazard ratio 0.8354 for each mg/kg increase, P<0.001). The two highest loading doses of BCNU improved survival 40-fold (P<0.001). The 20% BCNU-loaded 20:80 polymer achieved the best balance of toxicity and antitumor efficacy, yielding a 75% long-term survival rate. Further evaluation of this polymer in monkeys suggests that it might be used with acceptable toxicity. This study establishes that a dose-escalation strategy for improving BCNU controlled-release polymers is more effective than adjusting the ratio of CPP to SA to prolong drug release. Received: 21 February 1996/Accepted: 14 August 1996     

A phase I/II study of continuous infusion suramin in patients with hormone-refractory prostate cancer : toxicity and response

 Introduction: Suramin is a synthetic polysulfonated naphthylurea which has been used for the treatment of African trypanosomiasis and onchocerciasis, but since the mid-1980s has received attention as a possible antiretroviral and antineoplastic agent. Objective: This clinical trial of suramin was undertaken as a phase I/II study in patients with hormone-refractory prostate cancer, with the hypothesis that the intensity of therapy with suramin could be increased significantly if measures were undertaken to maintain the plasma concentrations of the drug under 300 μg/ml. Methods: We report the clinical results of this trial, wherein patients were treated at three different targeted plasma suramin concentrations (275, 215 and 175 μg/ml) for varying periods of time (2, 4 or 8 weeks), with delivery of the drug by continuous intravenous infusion. Results: The major toxicity observed in this trial was neurologic, consisting of a motor and sensory peripheral neuropathy that resulted in both paresis and paralysis of the limbs. Nearly all of this severe (CTEP grade III, IV) neurologic toxicity was observed in the patients treated at a plasma suramin concentration of 275 μg/ml for 4 or more weeks. A single patient treated at 215 μg/ml for 8 weeks developed moderate (CTEP grade III) proximal lower extremity weakness, and no patient treated at 175 μg/ml developed this toxicity. The second most common toxicity observed was infection of the central venous catheter. The overall response rate for all of the evaluable patients was 17% (13 of 75 patients). In addition, prostate-specific antigen (PSA)-defined responses were observed in six patients receiving therapy at 175 μg/ml, but these responses were confounded by cessation of therapy with flutamide during suramin treatment. Conclusions: In summary, although plasma suramin concentrations were maintained below 300 μg/ml, neurologic toxicity nonetheless occurred with high frequency in patients treated at 275 μg/ml for 4 or more weeks. Therapy at 215 and 175 μg/ml was in general well tolerated, but central venous catheter-related infection, as well as the inconvenience and expense of continuous infusional therapy, make this method of drug delivery impractical. Only moderate antitumor activity was observed during this trial, but it is possible that both continuation of flutamide and flutamide withdrawal during suramin therapy confounded the assessment of suramin’s activity in hormone-refractory prostate cancer. Received: 9 June 1995/Accepted: 18 March 1996     

The Inhibitory Effect of Oridonin on the Growth of Fifteen Human Cancer Cell Lines

OBJECTIVE To study the inhibitory effect of oridonin on the growth of cancer cells. METHODS Fifteen human cancer cell lines were subjected to various concentrations of oridonin in culture medium. The inhibitory rate of cell growth was measured by the MTT assay, and compared with a negative control and 5-Fu-positive control. RESULTS The 50% inhibiting concentration （IC50） and maximal inhibition （Imax） of oridonin shown by studying the growth of the cancer cell lines were as follows： leukemias （HL60 cells： 3.9 μg/ml and 73.8%, K562 cells： 4.3 μg/ml and 76.2%）; esophageal cancers（SHEEC cells： 15.4 μg/ml and 99.2%, Eca109 cells： 15.1 μg/ml and 84.6%, TEl cells： 4.0 μg/ml and 70.2%）; gastric cancers （BGC823 cells： 7.6 μg/ml and 98.7%, SGC7901 cells： 12.3 μg/ml and 85.7%）; colon cancers （HT29 cells： 13.6 μg/ml and 97.2%, HCT cells： 14.5 μg/ml and 96.5%）; liver cancers （Bel7402 cells： 15.2 μg/ml and 89.2%, HepG2 cells： 7.1 μg/ml and 88.3%）; pancreatic cancer （PC3 cells： 11.3 μg/ml and 68.4%）; lung cancer （A549 cells： 18.6 μg/ml and 98.0% ）; breast cancer （MCF7 cells： 18.4 μg/ml and 84.7%）; uterine cervix cancer （Hela cells： 13.7 μg/ml and 98.5%）. CONCLUSION Oridonin had a relatively wide anti-tumor spectrum, and a relatively strong inhibitory effect on the growth of the 15 human cancer cells. Inhibitory effects were concentration dependent.     

Anti-tumor Activities of Novel Estrogen Compound 17a α-D-Homo-Ethynylestradiol-3-Acetate

Objective： To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods： In vitro anti-tumor activity was assayed in adenoma cells A549 and human liver cancer cells Bel-7402 using MTT method, and half-inhibitory concentration （IC50） were observed. In vivo the pulmonary adenoma LA795 cells was selected and the conventional assay method of anti-tumor activity was employed. 5, 7.5, 10 mg/kg of 17a α-D-homo-ethynylestradiol-3-acetate was administered by i.p., and tumor-inhibitory rate, thymus and spleen indexes, bone marrow cells （BMC） were observed. Results： IC50 of 17a α-D-homo-ethynylestradiol-3-acetate in vitro for A549 and Bel-7402 cells were 12.28 μg/ml and 17.79 μg/ml, respectively. In vivo the highest tumor-inhibitory rates for LA795 was 60.0% （P〈0.01）. The drug had hardly any side-effect in spleen indexes, thymus indexes, and BMC compared with control mice. Nevertheless, compared with the positive control drug cyclophosphamide （CY）, thymus and spleen indexes, BMC showed obvious differences （P〈0.01）. Conclusion： 17a α-D-homo-ethynylestradiol-3-acetate has obvious anti-tumor activities in vitro and in vivo with low side-effect, thus worth further investigation.     

Pharmacokinetics of oral O6-benzylguanine and evidence of interaction with oral ketoconazole in the rat

Purpose: O⁶-Benzylguanine (BG) is a modulator of the DNA repair protein, O⁶-alkylguanine-DNA alkyltransferase (AGT). BG is converted in mice, rats and humans to an equally active, yet longer-lived metabolite, O⁶-benzyl-8-oxoguanine (8-oxo-BG) by CYP1A2, CYP3A4 and aldehyde oxidase. Since intravenous BG is expected to enter phase I development with orally administered anticancer agents such as temozolomide, procarbazine or SarCNU, we determined the bioavailability of orally administered BG, as well as the effect of ketoconazole, a potent intestinal and hepatic CYP3A4 inhibitor, on the disposition of BG. Methods: Following intravenous or oral administration of BG in PEG-400/saline (40:60) to Sprague-Dawley rats, the pharmacokinetics of BG and 8-oxo-BG were determined. To determine the effect of CYP3A inhibition on disposition, oral BG was coadministered with ketoconazole. Results: The peak plasma concentration (C_max), time to C_max (t_max), and bioavailability (F) of oral BG were: 2.3 ± 0.9 μg/ml, 2.3 ± 0.6 h, and 65.5% respectively. The AUCs of BG and 8-oxo-BG were 13.1 ± 4.6 μg · h/ml and 1.7 ± 0.4 μg · h/ml after oral administration of BG. Coadministration with ketoconazole resulted in an increase in mean absorption time from 2.0 ± 0.3 h to 6.0 ± 0.9 h, a shift in t_max to 5 ± 3.3 h, a decrease in C_max to 0.96 ± 0.8 μg/ml, and a decrease in AUC_0-inf ratio of 8-oxo-BG:BG from about 0.12 to 0.04 (P < 0.05). The bioavailability of BG was not changed (65.5% vs 56.9%, P=0.78). Conclusions: The oral bioavailability of BG is high, warranting consideration of an oral formulation for clinical development. Coadministration of ketoconazole and BG resulted in delayed oral absorption and inhibition of conversion of BG to 8-oxo-BG in the rat model. Received: 12 July 1999 / Accepted: 11 February 2000     

Combination of paclitaxel thermal gel depot with temozolomide and radiotherapy significantly prolongs survival in an experimental rodent glioma model

OncoGel? incorporates paclitaxel, a mitotic inhibitor, into ReGel?, a thermosensitive gel depot system to provide local delivery, enhance efficacy and limit systemic toxicity. In previous studies the alkylating agent temozolomide (TMZ) incorporated into a polymer, pCPP:SA, also for local delivery, and OncoGel were individually shown to increase efficacy in a rat glioma model. We investigated the effects of OncoGel with oral TMZ or locally delivered TMZ polymer, with and without radiotherapy (XRT) in rats with intracranial gliosarcoma. Eighty-nine animals were intracranially implanted with a 9L gliosarcoma tumor and divided into 12 groups that received various combinations of 4 treatment options; OncoGel 6.3 mg/ml (Day 0), 20 Gy XRT (Day 5), 50 % TMZ–pCPP:SA (Day 5), or oral TMZ (50 mg/kg, qd, Days 5–9). Animals were followed for survival for 120 days. Median survival for untreated controls, XRT alone or oral TMZ alone was 15, 19 and 28 days, respectively. OncoGel 6.3 or TMZ polymer alone extended median survival to 33 and 35 days, respectively (p = 0.0005; p < 0.0001, vs. untreated controls) with 50 % living greater than 120 days (LTS) in both groups. Oral TMZ/XRT extended median survival to 36 days (p = 0.0002), with no LTS. The group that received OncoGel and Oral TMZ did not reach median survival with 57 % LTS (p = 0.0002). All other combination groups [OncoGel/XRT], [TMZ polymer/XRT], [OncoGel/TMZ polymer], [OncoGel/TMZ polymer/XRT], and [OncoGel/oral TMZ/XRT] yielded greater than 50 % LTS (p < 0.0001 for each combination as compared to controls), therefore median survival was not reached. OncoGel/TMZ polymer and OncoGel/oral TMZ/XRT had 100 % LTS (p < 0.0001 and p = 0.0001 vs. oral TMZ/XRT, respectively). These results indicate that OncoGel given locally with oral or locally delivered TMZ and/or XRT significantly increased the number of LTS and improved median survival compared to oral TMZ and XRT given alone or in combination in a rodent intracranial gliosarcoma model.     

Irinotecan in combination with thalidomide in patients with advanced solid tumors: a clinical study with pharmacodynamic and pharmacokinetic evaluation

Purpose: Recent clinical studies have demonstrated a reduction of irinotecan (CPT-11) gastrointestinal toxicities when the CPT-11 is administered in combination with thalidomide in patients with diagnosis of colorectal cancer. The main purpose of this study was to investigate possible interactions between CPT-11 pharmacokinetics and thalidomide to explain the previously described gastrointestinal toxicity reduction. Methods: In our clinical trial, advanced cancer patients were treated with CPT-11 on a dose of 350 mg/m² at day 1 every 3 weeks. Only at the first cycle, CPT-11 was administered in association with thalidomide on a dose of 400 mg/day given from day 1 to day 14. From the second cycle, the treatment was continued with irinotecan alone at the same dose. Pharmacokinetics analysis of irinotecan and its metabolites, SN-38 and SN-38-glucuronide, were performed at the first and second cycle. Results: A total of 19 patients entered the study. The pharmacokinetic analysis were performed on 16 patients. Pharmacokinetic data suggested a decreased metabolism of irinotecan into SN-38 and SN-38-glucuronide when it was administered with thalidomide. Indeed, area under the time–concentration curve (AUC) of SN-38 was significantly lower at the first cycle than the second cycle (0.99±0.45 h×μg/ml vs 1.34±0.65, respectively, P=0.027) whereas AUC of irinotecan and SN-38-glucuronide were higher at first cycle than second cycle (34.53±11.38 h×μg/ml vs. 28.42±12.23 h×μg/ml, P=0.064 and 2.39±1.21 h(μg/ml vs. 1.86±1.11 h×μg/ml, P=0.018, respectively). Conclusions: Our study demonstrates a significant decreased metabolism of CPT-11 into the active metabolite SN-38 when CPT-11 is administered in association with thalidomide. These observations strongly suggest an interaction of thalidomide with CPT-11 metabolism and, at least in part, it might explain the previously described improvement in tolerability.Grant support: The work was partially supported by Associazione Italiana Ricerca Cancro (AIRC) and Fondazione A.R.C.O.     

Anti-Tumor Effect of Curcumin on Human Cervical Carcinoma HeLa Cells In Vitro and In Vivo

Objective: To investigate the anti-tumor effect of curcumin on human cervical carcinoma HeLa cells in vitro and in vivo. Methods: (1) Human cervical carcinoma cell line HeLa was cultured in vitro. HeLa cells were treated with 5-50 μmol/L curcumin for 24. 48, 72 h and the growth inhibition rates of HeLa cells were measured by MTT method. Cell apoptosis was inspected by electron microscopy and flow cytometry (FCM). (2) A transplanted tumor model by injecting HeLa cells into subcutaneous tissue of BABL/C mice was established and its growth curve was measured. 30 BABL/C mice with tumors were divided into 2 groups at random and 0.2 ml saline or 0.2 ml 250 μmol/L curcumin was injected into abdominal cavity respectively once everyday and lasted for ten days. The changes of tumor volume were measured continuously and tumor inhibition rate was calculated. At last the expressions of caspase-3 and bax protein in transplanted tumors were detected by immunohistochemistry. Results: (1) Curcumin inhibited the proliferation of Lela cells on a dose-depending manner. Apoptosis of cells could be observed by FCM. Partial cells presented the characteristic morphological changes of apoptosis under electron microseope. (2) When 1×107 HeLa cells were inoculated for each mouse, 100% of the mice developed growing tumors after seven days. An inhibition effect was observed in treatment group, and the inhibition rate of curcumin was 74.33%. The expressions of caspase-3 and bax in the transplanted tumors were increased in curcumin group. Conclusion: Curcumin is effective as an anti-cancer drug not only in vitro but also in vivo.     

Serum protein binding of lerisetron, a novel specific 5HT3 antagonist, in patients with cancer

The aim of this study was, (1) to characterize the serum protein binding of lerisetron, a new 5-hydroxytryptamine (5-HT₃) receptor antagonist under investigation as an antiemetic agent, and (2) to measure the percentage of unbound lerisetron in cancer patients. The binding parameters were determined in human serum albumin (HSA), α₁-acid glycoprotein (AAG) and in pooled serum from six healthy volunteers. Concentrations of lerisetron ranging from 50 ng/ml to 2 μg/ml were used. The serum protein binding of ¹⁴C-lerisetron (2 μg/ml) was determined by ultrafiltration in three groups of individuals. Group I comprised healthy subjects (n = 11), group II comprised cancer patients undergoing radiotherapy (n = 9), and group III comprised cancer patients receiving chemotherapy (n = 18). The unbound concentration of lerisetron was measured in all samples by liquid scintillation counting. Concentrations of both AAG and HSA were also measured in all serum samples. The drug was extensively bound in pooled serum, involving a nonsaturated process. In HSA, lerisetron was also highly bound (4.04 ± 0.8% unbound) and the protein binding was essentially unchanged within the studied concentration range of lerisetron. The extent of binding to AAG was high but significantly lower than in serum and in HSA and was also independent of lerisetron concentration. The unbound lerisetron was significantly decreased in group II cancer patients when compared with group I subjects (2.38 ± 0.64% vs 3.70 ± 0.70%; P < 0.001). No significant changes in lerisetron binding were observed in group III patients. HSA was diminished in both groups of patients and AAG was only significantly increased in group II. Unbound lerisetron was correlated with AAG in group II and with HSA in group III. Received: 8 August 1997 / Accepted: 27 February 1998