Selective cancer therapeutics最新文献

Twenty patients with focal malignant obstruction of the major bile ducts (6 cholangiocarcinoma, 8 colorectal, 3 hepatoma, 2 unknown primary, and 1 gastric cancer) were treated on a protocol examining the toxicity and efficacy in relieving jaundice of external beam radiation therapy (4500 cGy in 300 cGy fractions) combined with continuous hepatic arterial (15 patients) or peripheral venous (5 patients) fluorouracil infusion. Toxicity of this regimen consisted of anorexia with mild nausea and vomiting in 55% of patients and gastric ulceration (responsive to medical management) in 15% of patients. One patient exhibited transient grade 2 hepatic toxicity and one had asymptomatic grade 4 leukopenia. Of 14 patients treated without prior biliary drainage, 8 exhibited a decrease in bilirubin levels from a mean of 14.5 mg/dl to 1.5 mg/dl. Four of six patients with biliary drainage catheters at the start of treatment were able to have them removed without reobstruction. For the 8 responding patients among those who did not have cholangiocarcinomas, the median response duration was 5 months with a median survival from treatment of 6.5 months. For the 4 responding patients with cholangiocarcinoma, the median response duration was 16 months with a median survival from treatment of 20 months. All responders did not have a return of jaundice due to reobstruction of the major ducts (until death or to the present). All responders who have died did so due to tumor progression outside of the treated field except for one who died of unrelated causes. The mean number of proven or presumed episodes of cholangitis per patient was virtually identical in those without (1.8) and those with stents/tubes (1.4, p = 0.561). This regionally focused combined modality cytotoxic therapy was able to relieve obstruction in the majority of patients without excess morbidity (including a lack of any detectable increase in sepsis). Thus, it appears feasible to consider randomized studies of this cytotoxic approach versus standard mechanical drainage procedures to define the relative risks and benefits of each.

Loco-regional intra-arterial chemotherapy of hepatic metastases from colo-rectal cancer is one of the most effective non-surgical treatments in this clinical situation. In our experience of 58 cases treated during 3 years, in a non randomized study by either: 1) discontinuous perfusion of 5FU (using a subcutaneous access) or 2) by continuous infusion of FUDR (using an implantable pump), we observed an objective response rate of 52% and 53% with a 1 year survival of 73% and 90%, respectively. This technique, however, is limited in its application by loco-regional complications and in its long term efficacy by the development of extrahepatic metastases. The proof of its efficacy in terms of survival prolongation, is being studied within the framework of a prospective randomized trial with a control group.

Infusion of etoposide has previously been evaluated in phase I trials. Vincristine (VCR) given by infusion has been shown in a phase II trial to be active in some cases of non-Hodgkin's lymphoma despite prior exposure to bolus VCR. Infusion of etoposide and the combination of VCR infusion with etoposide (given either as an infusion or bolus) were evaluated in 24 patients with previously treated non-Hodgkin's lymphoma. Five-day infusions of etoposide alone (n = 10), both etoposide and VCR (n = 9), or VCR with bolus etoposide (n = 5) were evaluated. Partial responses were observed in 0, 2 (22%), and 1 (20%) of the patients, respectively. Myelosuppression was the principal toxicity with the 5-day infusions of etoposide alone and with the double infusion combination, but was mild in the VCR infusion coupled with etoposide bolus. Non-hematologic toxicity was mild to moderate in each. For patients with refractory non-Hodgkin's lymphoma, the infusion of etoposide with or without VCR infusion appeared to offer no advantage over bolus administration of etoposide or infusion of VCR alone.

The membrane-active ionophores were observed to possess antifungal activity against Candida albicans 336 and were toxic to human erythrocytes. Liposome encapsulation of these drugs significantly reduced their toxicity to erythrocytes but resulted in the loss of their antifungal potency. These results are compared with membrane-active polyenes which maintained their antifungal activity after encapsulation into liposomes. Liposomal-ionophores, however, showed antifungal activity along with low concentrations of Amphotericin B indicating the presence of synergism between these drugs.

The macrophage population of the liver has been reported to be heterogeneous with respect to endocytic and lysosomal enzyme activity. Yet we demonstrate that all liver macrophages in the rat can be activated to a tumoricidal state by the i.v. injection of liposomal muramyl dipeptide (MDP). After isolation, liver macrophages were fractionated according to size into five subfractions by means of elutriation centrifugation. Tumoricidal activity of liver macrophages, activated in vivo, was determined by an in vitro radioactivity release assay using B16 melanoma and C26 adenocarcinoma cells, labeled with [methyl-3H]thymidine, as target cells. Endocytic activity of the subpopulations both in vitro and in vivo was determined using [3H]-labeled liposome preparations. Finally, the extent to which the subpopulations become cytotoxic as a result of in vitro uptake of muramyl dipeptide-(MDP)-containing liposomes was studied employing the cytotoxicity assay described above. No significant differences in cytotoxicity between the macrophage subfractions were observed after i.v. injection of liposomal MDP, although endocytic uptake of liposomes per cell increased proportionally to cell size, both in vitro and in vivo. We found that in vitro uptake of MDP-containing liposomes by the subfractions produced the highest cytolytic activity in the small to intermediate-size macrophages. When taking into consideration the different extents of liposome uptake it can be concluded that the smaller liver macrophages are significantly more susceptible to activation than the larger cells. In vivo, low activation potential is balanced by high liposome uptake capacity thus allowing the whole macrophage population in the liver to become involved in the eradication of metastatic tumor growth.

At present, cytotoxicity measurements using the fluorescent cytoprint assay are based on achieving complete cell death in cultures of drug-sensitive tumors. Thus, the usefulness of the assay would be extended if partial effects of chemotherapeutic drugs could be quantified. In this study, we addressed the issue by developing and validating a thresholding algorithm for automatic image processing that can be used to quantify the areas occupied by viable (i.e., fluorescent) micro-organs in the culture.

Present therapy of human superficial bladder cancer includes the intravesical administration of antitumor drugs and immunomodulators. The purpose of these studies was to determine whether liposomes can bind to human bladder cancer cells and thereby provide a mechanism to improve the delivery of anticancer agents to diseased urothelium. Negatively charged large multilamellar vesicles (MLVs) bound to four different human bladder tumor cell lines (253J, J82, T24, TCCSUP) more avidly than did small sonicated vesicles or vesicles consisting of uncharged phosphatidylcholine (PC). Of the three types of negatively charged MLVs tested, phosphatidylcholine/phosphatidylserine (7:3, mol ratio) (PC/PS) MLVs bound the most. MLV binding to tumor cells was saturable and appeared to be specific. In contrast, the binding of liposomes to normal fetal bladder cells was minimal. These data suggest that targeting of drugs to superficial bladder cancer can be achieved by the intravesical administration of PC/PS MLV.

The therapeutic efficacy of 5-fluorouracil (FUra) and cis-dichlorodiamine-platinum (cis-DDP) in mice bearing transplantable leukemia and solid tumors was evaluated using different sequences of combination of these agents. The optimal sequence was cis-DDP administered 24 h after FUra. The administration of FUra at its maximally tolerated dose (MTD) followed 24 h later by low doses of cis-DDP yielded less toxicity and higher response rate against L1210 and colon 26 than the administration of these two agents in the opposite sequence or concurrently at the MTD. The sequence of administration of these two agents was not therapeutically important when the antitumor activity was evaluated against mice bearing lymphoma P388. These results indicate that the importance of sequencing of FUra and cis-DDP varies among different tumors. The biochemical basis for the therapeutic importance of sequencing in treatments with cis-DDP and FUra was investigated in mice bearing leukemia L1210 cells. While cis-DDP has no significant effects on the activity of thymidylate synthase (dTMP-S), the target enzyme for FUra action, recovery of dTMP-S inhibition following pretreatment with FUra was significantly delayed when cis-DDP was administered 12-24 h after the initial dose of FUra.

We have previously shown that 5-fluorouracil (FUra) in humans obeys Michaelis-Menten elimination kinetics. In this article we show that the related bromine and iodine-containing analogs in animals obey similar kinetics. Steady-state arterial (CssA) and hepatic venous plasma (CssV) concentrations of 5-bromo-2'-deoxyuridine (BrdUrd) are reported for 7 rabbits given 5 different infusion rates of BrdUrd and 5 dogs given 4 or 5 different infusion rates of BrdUrd. Steady-state arterial and hepatic venous plasma concentrations of 5-iodo-2'-deoxyuridine (IdUrd) are reported for 5 rabbits and 2 dogs given 5 different infusion rates of IdUrd. Each set of data could be fitted by a nonlinear least squares method to the equation: (equation; see text) where Vm/Q is the maximum difference, (CssA) - (CssV), and Km is the Michaelis constant. The estimated parameter Vm/Q and Km are compared for the two drugs and different species and also with the same parameters derived in the same manner from previously published data on fluorouracil in 8 cancer patients. The infusion rate needed to saturate the splanchnic elimination system (Rs in mumol/kg/min) was also estimated. For BrdUrd the mean value of Rs in the rabbit, namely 1.23, and in the dog, namely 1.25 mumol/kg/min are essentially the same.