Selective cancer therapeutics最新文献

Crisnatol is an arylmethylaminopropanediol derivative that has shown promise as an antitumor agent in preclinical testing. In a phase I trial using a monthly six-hour infusion schedule the recommended dose for future phase II trials was found to be 388 mg/m2. Neurologic toxicity was dose-limiting in that trial and correlated with the attainment of a threshold plasma concentration of greater than 4.5 micrograms/ml. In this study we treated 15 patients with escalating doses of crisnatol from 450 mg/m2 to 900 mg/m2 administered at a rate of 50 mg/m2/hr over 9, 12, 15, and 18 hours. Toxicity was mild to moderate at all dose levels. However, serious central nervous system effects were noted in one patient at 900 mg/m2 over 18 hours whose plasma level was 6.5 micrograms/ml. This study has demonstrated higher total doses of crisnatol can be given if the drug is administered as a prolonged infusion in an attempt to avoid high plasma levels of the agent.

We compared the toxicity of free and liposome-entrapped retinoid, Ro13-7410 in C2DF1 mice. Mice received 7 daily i.p. injections of liposome-entrapped Ro13-7410 at doses of 5, 10, 100, 500, or 1000 micrograms/kg bw/day. For comparison, two groups of mice were used as controls, one group received Ro13-7410 in corn oil and a second group received liposome-entrapped Ro13-7410 that had been solubilized with detergent. The liposomes were then tested for chemotherapeutic activity against human myelocytic leukemia (HL-60/MRI) implanted in athymic NCr-nu mice. The doses used in the chemotherapy experiment (20, 50, and 100 micrograms/kg bw/day) were selected based on the results of the toxicity experiment in CD2F1 mice. CD2F1 mice were marginally protected from toxicity after receiving retinoid in liposomes relative to controls. There were 2/5 survivors in the 1000 micrograms/kg bw/day Ro13-7410-liposome group after 7 daily i.p. doses compared to 0/5 for both the corn oil and solubilized liposome groups, and 4/5 survivors in the 500 micrograms/kg bw/day Ro13-7410-liposome group after 7 daily i.p. doses compared to 2/5 for both the corn oil and solubilized liposome groups. We observed no dramatic differences in toxicity among the treatment groups over the range of doses administered. There were 2/6 long-term tumor-free survivors in athymic mice receiving liposome-entrapped retinoid, at 50 micrograms/kg bw/day for 7 days, compared with 0/6 and 0/9 survivors in groups receiving empty liposomes or no treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of adriamycin (ADR), vincristine (VCR), mitoxantrone (MTN) and cis-platin (PtCl) at acidic pH on the incorporation of 3H-thymidine (3H-TdR) was studied in vitro on P388 murine leukemia cells. The incorporation was inhibited at low pH by the four drugs used. In order to induce acidosis in tumor bearing mice, 6 g/kg glucose was administered intraperitoneally. The lowest pH that could be obtained was 6.8 two hours after glucose administration. The drugs ADR, VCR, MTN and PtCl administered to tumor-bearing mice 2 h following induction of acidosis resulted in significant increase in the life span of the tumor bearing mice.

We analyzed the expression of P-glycoprotein (Pgp) by immunohistochemistry using JSB-1 monoclonal antibody (MAb) on paraffin-embedded sections of the multi-drug resistant (MDR) (CHrC5 and CEM-VLB), and sensitive (AuxB1 and CEM) cell lines, and also in normal kidney, colon, adrenal and in kidney and colon carcinomas. After comparing the sensitivity of three different immunohistochemical techniques the peroxidase-antiperoxidase method was found to be the best. We then tested six different fixation methods. The MDR cell lines and human tissues demonstrated the strongest staining with B-5 fixative. Both MDR cell lines, but not the tissues fixed in 1% paraformaldehyde and Zamboni's fixative demonstrated weak staining. No immuno- reactivity could be detected in MDR cell lines and tissues fixed in 10% buffered or nonbuffered formalin or by the AMeX method of tissue processing. The present study clearly shows that the type of fixative is critical for the preservation of Pgp epitope recognized by JSB-1 MAb, and that B-5 fixative is expected to be equally applicable for the detection of Pgp in normal and neoplastic tissues.

5-Fluorouracil (5FU) is the most effective drug in gastrointestinal cancer. Mucositis and bone marrow toxicity are the two major limiting side effects. In our effort to reduce mucositis we administered Allopurinol mouthwash in 42 patients who had experienced oral mucositis during prior treatment with 5FU. In all patients significant reduction of oral toxicity was noticed as well as prolonged pain relief.

Autoradiographic analysis of the intratumor location of radioiodinated Mu-9 anti-CSAp antibody within 7 days of administration reveals a restricted distribution within 3-6 cell layers surrounding tumor vessels. Within 7-14 days after suboptimal radioantibody treatment (approximately 3000 rads), tumor vessel morphology and physiology are altered. Vessel number is reduced by 60-70%, vessel diameter is reduced, and remaining vessels are surrounded by fibrotic tissue. Vascular volume (VV) is reduced by 75%, blood flow rate (BF) is reduced 65%, and vascular permeability (VP) to an IgG is reduced by 60%. The change in VV is reversible by day 35 but BP and VP remain suppressed. Normal tissue (liver and lung) vasculature experience only small pertubations in physiology. These functional changes in tumor vessels reduce the magnitude of accretion of a second dose of radioantibody in tumor but not in normal tissue.

Microspheres conjugated to radioisotopes and chemotherapeutic agents are playing an important investigative and clinical role in the management of metastatic neoplasms. The purpose of our investigation was to histologically assess the basis for regional intra-arterial microsphere therapy, by comparing the spatial distribution of microspheres in the tumor and liver of experimental models of hepatic metastases. Three New Zealand white rabbits with hepatic VX2 tumor implants were arterially injected with hepatic doses of either 15 or 30 million blue-dyed, polystyrene microspheres (27 microns-diameter). Microscopic examination of random liver and tumor samples revealed that 6-12 times as many microspheres were embolized within tumor than in normal liver (p less than 0.002). The majority of microspheres aggregated into clusters of various size within liver and tumor vasculature, though analysis of cluster sizes illustrated an exponentially skewed distribution toward isolated microspheres. Approximately eight times as many clusters were observed in tumor than in liver (p less than 0.008). Finally, a morphometric analysis was used to quantitate the minimal distances separating microsphere clusters, the intercluster distance (ICD). Analysis of over three thousand intercluster measurements revealed a median ICD approximately five times lower in tumor than in liver (p less than 1 x 10(-8)). This microquantitative analysis provides a fundamental description of how regional intra-arterial microsphere therapy allows the targeted delivery of microspheres to neoplastic tissue, to potentially improve the therapeutic index in the treatment of hepatic metastases.

(N-(2-Hydroxypropyl)methacrylamide (HPMA)) copolymers have seen extensive development as sophisticated lysosomotropic drug carriers. They can be used for site-specific drug delivery by incorporation of appropriate targeting groups and here we report their conjugation to antitumour monoclonal antibodies (the murine IgG, antibody B72.3 and its Fab' and Fab'2 fragments) and assessment as vehicles for tumour-specific drug delivery. Conjugates were synthesised containing an average 5 copolymer units (Mw 20kD) per antibody molecule. Kinetics of elimination and body distribution of radiolabelled conjugates in mice were substantially modified compared with native antibody and fragments, showing prolonged circulation in the bloodstream. Notably, the half-time for bloodclearance of the Fab' fragment (35min) was extended ten-fold following conjugation (6h). The conjugates provoked only a low immune response in A/J mice, following three injections in adjuvant (IgG titre-1 less than 100), and were resistant (up to 50%) to proteolytic degradation by preparations of rat liver lysosomal enzymes. The parent antibody targeted efficiently to human colorectal carcinoma (LS174T) xenografts in nude mice (up to 25%/g); the conjugates, however, showed no tumour-targeting, probably due to masking by polymer chains (which are attached by non-specific aminolysis). Conjugates designed to maintain immunoreactivity following linkage through oxidised carbohydrates are currently being synthesised. Nevertheless, the conjugates display increased rates of extravasation, compared with proteins of the same hydrodynamic size, and the decreased charge is anticipated to accelerate diffusion through tumour interstitium.

Utility of drug response modulators to increase therapeutic:toxic ratio of anticancer drugs in the treatment of refractory malignancies is becoming desirable. In this study, we have attempted to potentiate the tumor cell killing ability of Adriamycin (ADR) against chronic myeloid leukemia cells (CML), in the presence of vitamin K3. Cell growth was evaluated by the MTT assay and the 3H-thymidine incorporation inhibition assay. A highly significant (p less than 0.001) inhibition of cell survival and 3H-thymidine incorporation was effected in CML cells exposed to the combination of ADR and vitamin K3. When the CML cells were treated with ADR and vitamin K3 simultaneously, a greater fragmentation of the intact DNA was revealed as observed by the enhanced formation of DNA single strand breaks. Results demonstrate the therapeutic significance of employing vitamin K3 as an adjuvant in CML chemotherapy with ADR.