Evaluation of the efficacy, toxicity and safety of vinorelbine incorporated in a lipid emulsion.

To reduce the severe adverse effects of vinorelbine (VRB) with the aim of improving patient compliance, a parenteral vinorelbine-loaded lipid emulsion (VLE) has been developed. The objective of the present study was to get insight into the preclinical antitumor efficacy, toxicity and safety of VLE, and compare this with that of the commercial product, Navelbine(®) i.v. (VS). Comparable antitumor efficacy of VLE and VS was observed in tumor-bearing nude mouse models inoculated with A549 human lung cancer, hepatoma solidity (Heps) G2 cancer and BCAP-37 human breast cancer cells. The median lethal dose (LD(50)) in mice was 29.3mg/kg (male) and 32.1mg/kg (female) for VLE, while the corresponding value was 30.5mg/kg (male and female) for VS. In the long-term toxicity study, VLE significantly reduced the decreases in RBC, HC, WBC and WBC differential count (DC) levels. Lesions in spleen, thymus, lymph nodes, bone marrow, testis, ovary and injection site induced by VS were much more severe compared with VLE. VLE also exhibited less local venous irritation than VS, as well as no hemolysis or hypersensitivity. Consequently, these observations clearly indicate that the lipid emulsion could be a useful potential parenteral carrier for VRB with equivalent efficacy and lower toxicity.

Effects of plants and plant products on the testis.

For centuries, plants and plant-based products have been used as a valuable and safe natural source of medicines for treating various ailments. The therapeutic potential of most of these plants could be ascribed to their anticancer, antidiabetic, hepatoprotective, cardioprotective, antispasmodic, analgesic and various other pharmacological properties. However, several commonly used plants have been reported to adversely affect male reproductive functions in wildlife and humans. The effects observed with most of the plant and plant-based products have been attributed to the antispermatogenic and/or antisteroidogenic properties of one or more active ingredients. This review discusses the detrimental effects of some of the commonly used plants on various target cells in the testis. A deeper insight into the molecular mechanisms of action of these natural compounds could pave the way for developing therapeutic strategies against their toxicity.

P-glycoprotein (multi-xenobiotic resistance) and heat shock protein gene expression in the reef coral Montastraea franksi in response to environmental toxicants.

The deleterious impacts of marine pollutants on reef corals and their symbiotic algae are an important element of global coral reef decline. In the current study we examined the impacts of toxicants on the reef coral Montastraea franksi by analysing the expression of three stress-related genes belonging to the coral host, using Taqman real-time quantitative reverse transcription-PCR. Gene expression profiles of P-glycoprotein (or multi-xenobiotic resistance protein) (P-gp); heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) were examined following 4 and 8h exposures to the heavy metal copper (3, 10, 30 and 100 microgL(-1)) or the third generation oil dispersant Corexit9527 (1, 5, 10 and 50 ppm). Additionally, the expression of P-gp was examined following exposure to 0.5 and 5 microM concentrations of the chemotherapeutic drug vinblastine, a classic substrate of P-gp. The expression of P-gp increased significantly in corals treated with vinblastine and also increased following exposure to copper and Corexit9527. Hsp70, and to a lesser extent Hsp90 expression increased following exposure to copper and Corexit9527 indicating a general cellular stress response. Densities of symbiotic algae in the tissues of the corals did not change significantly during the experiments, nor was any loss or paling of coral tissues observed. These findings provide important insight into how corals defend themselves against pollution and complement ongoing initiatives developing molecular biomarkers of stress in reef-building corals.

Pharmacological effects of vinorelbine on body temperature and locomotor activity circadian rhythms in mice.

The effects of vinorelbine (VRL) on the circadian rhythms in body temperature and locomotor activity were investigated in unrestrained B6D2F1 mice implanted with radio-telemetry transmitters. A single intravenous VRL dose (24 or 12 mg/kg) was given at 7 h after light onset (HALO), a time of high VRL toxicity, and resulted in transient suppression of temperature and activity circadian rhythms in mice kept in light-dark (LD) 12h: 12h. Such suppression was dose-dependent. It occurred within 1-5 d after VRL dosing. Recovery of both rhythms was partially complete within 5 d following the high dose and within 2 or 3 d after the low dose and was not influenced by suppression of photoperiodic synchronization by housing in continuous darkness. Moreover, VRL induced a dose-dependent relative decrease in amplitude and phase shift of the temperature circadian rhythm. The mesor and amplitude of the activity rhythm were markedly reduced following the VRL administration. The relevance of VRL dosing time was studied in mice housed in LD 12h:12h. Vinorelbine was injected weekly (20 mg/kg/injection) for 3 wk at 6 or 18 HALO. Vinorelbine treatment ablated the rest-activity and temperature rhythms 3-6d after each dose, with fewer alterations after VRL dosing at 18 HALO compared to 6 HALO, especially for the body temperature rhythm. There was at least partial recovery 1 wk after dosing, suggesting the weekly schedule of drug treatment is acceptable for therapeutic purposes. Our findings demonstrate that VRL can transiently, yet profoundly, alter circadian clock function. Vinorelbine-induced circadian dysfunction may contribute to the toxicokinetics of this and possibly other anticancer drugs.

Relationship between circadian rhythm of vinorelbine toxicity and efficacy in P388-bearing mice.

The relevance of chronopharmacology for improving tolerability and antitumor efficacy of the antimitotic drug vinorelbine was investigated in female B6D2F1 mice standardized with 12 h of light and 12 h of darkness. A single i.v. vinorelbine dose (26 mg/kg) was given to 279 mice at 7, 11, 19, or 23 hours after light onset (HALO). Bone marrow necrosis and leukopenia were nearly twice as large in the mice injected at 7 HALO as compared with those treated at 19 HALO (ANOVA: p <.001 and p = 0.004, respectively). The relevance of vinorelbine dosing time for antitumor efficacy was assessed in 672 P388 leukemia-bearing mice. Vinorelbine was injected as a single dose (20, 24, 26, or 30 mg/kg) or weekly (20, 24, 26, or 28 mg/kg/injection x 3) at one of six circadian times, 4 h apart. A significant correlation between single dose and median survival time was limited to vinorelbine administration at 19 or 23 HALO. An increase in the vinorelbine weekly dose shortened median survival time in the mice treated at 7 HALO (20 mg/kg: 29 days; 24 mg/kg: 17 days; and 26 mg/kg: 6 days) but significantly improved it in those treated at 19 HALO (20 mg/kg: 28.5 days; 24 mg/kg: 32 days; and 26 mg/kg: 36 days). The study demonstrates the circadian rhythm dependence of maximum tolerated dose and the need to deliver maximum tolerated dose at the least toxic time to achieve survival improvement through chronotherapy. This may be obtained with an evening administration of vinorelbine in cancer patients.

Potential interactions between antitubulin agents and temperature: implications for modulation of multidrug resistance.

We analyzed the effect of high temperature (a 1-h incubation at 43 degrees C) on the accumulation and cytotoxicity of vinblastine and docetaxel in two model cell lines, K562 and MESSA, and their multidrug resistance (MDR) counterparts, K562/R7 and MESSA/Dx5. High temperature increased the amount of intracellular vinblastine and docetaxel significantly in MESSA cell and, to a much lesser extent, in K562 cells. MDR-positive cells retained a profound drug accumulation defect at 43 degrees C. Hyperthermia enhanced the cytotoxic effect of vinblastine (but not docetaxel) in both K562 and MESSA cells, but not in the MDR-positive variants. PSC833, a potent modulator of P-glycoprotein, induced high levels of drug accumulation in the two MDR-positive cell lines at both 37 degrees C and at 43 degrees C. PSC833 also significantly reduced the resistance levels of the two MDR-positive lines at both 37 degrees C and at 43 degrees C. The effect of hyperthermia on drug accumulation thus seems to depend on the cell line, whereas the effect on cytotoxicity depends on the type of compound. The MDR phenotype remains a therapeutic obstacle at 43 degrees C but is accessible to modulation.

Antidote studies of vinorelbine-induced skin ulceration in the mouse.

The new cantharanthine-modified vinca alkaloid vinorelbine (Navelbine) was administered intradermally (ID) to dehaired BALB/c mice. Dose-dependent skin lesions were produced over the range 0.01-0.5 mg/mouse, with complete healing after 9-35 days. Local (ID) injections of hydrocortisone and saline were ineffective at blocking vinorelbine-induced skin ulceration. Topical skin heating to 43 degrees C or cooling to 10 degrees C were also ineffective. In contrast, hyaluronidase, 15 Units ID, following vinorelbine significantly reduced skin lesions. These results show that vinorelbine is a vesicant and that inadvertent extravasations may be managed with subcutaneous injection of the spreading factor enzyme, hyaluronidase.

Modulation of cytostatic drugs by nifedipine in two heterotransplanted human testicular-cancer cell lines differing in their sensitivity to standard agents.

Drug resistance is an important clinical problem in testicular cancer patients with relapsed or refractory disease after first-line chemotherapy. Here we report that the relative reduction in tumour volume in nude mice heterotransplanted with either H 12.1 or H 23.1 human testicular cancer cell lines was significantly increased by addition of the calcium antagonist nifedipine to the maximum tolerated dose (MTD) of cisplatin (DDP). The mean reduction in relative tumour volume at day 30 (rVR) reached statistical significance for both cell lines following combination therapy of DDP with nifedipine compared to DDP alone (55 +/- 7% versus 12 +/- 4% for H 23.1 and 60 +/- 9% vs. DDP with nifedipine has also been confirmed in H 12.1 cells in vitro. However, in vivo, this combination was associated with a concordant increase in therapeutic toxicity. In contrast, no improvement in in vivo anti-tumour activity was obtained by combining similar dose-schedules of nifedipine with the MTD of epirubicin, or with MTDs of vinblastine or etoposide. These results are in agreement with our immunohistochemical finding that H 12.1 and H 23.1 do not over-express the Pgp 170 glycoprotein which mediates the multiple drug resistance (MDR) phenotype and involves both anthracyclines and vinblastine, but not DDP. We conclude that another Pgp-MDR modulator, nifedipine, is able to increase the anti-tumour activity of DDP in vivo and in vitro via a specific but as yet unknown mechanism, which is most likely not MDR-related. However, the increased anti-tumour activity is, in vivo, associated with a considerable increase in overall toxicity. Further studies are necessary to decrease therapeutic toxicity, before clinically relevant models for modifiers of DDP-resistance could possibly be applied to patients.

Pentose phosphate pathway alterations in multi-drug resistant leukemic T-cells: 31P NMR and enzymatic studies.

31P NMR studies were carried out on the parental drug-sensitive human T-lymphoblastoid cell line CCRI-CEM (CEM) and its multi-drug-resistant (MDR) CEM-VBL100 variants, to assess the role of the pentose phosphate (PP) in MDR expression. CEM and CEM-VBL100 were incubated in the presence of 2-deoxyglucose, as recently proposed by our group (Clin. Chim. Acta 208: 39, 1992). Accumulation of 2-deoxyglucose 6-phosphate was much lower in the drug-resistant than in sensitive cells, indicating PP shunt activation in the MDR variants. This result was confirmed by enzymatic analyses, which demonstrated that, with respect to the parental line, the MDR variant was characterized by a) unaltered hexokinase activity; b) higher glucose 6-phosphate dehydrogenase activity; c) increased levels of reduced glutathione and marked increase of glutathione peroxidase activity after cell exposure to an oxidizing agent (tert-butylhydroperoxide). These results support the view that cell detoxification mechanisms mediated by the pentose phosphate pathway may contribute to the expression of MDR in tumours.

Advances in vinca-alkaloids: Navelbine.

Vinorelbine (Navelbine) is a new semisynthetic vinca alkaloid which chemically differs from vinblastine by substitutions on the catharantine moiety of the molecule. It has shown promising experimental antitumor activity against experimental murine tumors as well as continuous cell lines of human neoplastic origin and human tumor xenografts in nude mice. Acute subacute and chronic toxicity extensively studied in rodents, dogs and primate has shown that hematotoxicity was almost the sole side-effect; neurotoxicity appears very limited. Almost exclusive affinity of NVB for mitotic tubulin and tubulin associated protein accounts for this pattern of toxicity. Phase I and II studies have been conducted in humans. Dose limiting side-effect appears to be neutropenia: the drug is slightly emetogenic, induces little alopecia, almost no neurotoxicity, and no other toxicity. Although preliminary, results of phase II studies already suggest significant activity of NVB in non small lung cancer (33% response rate in 78 evaluable patients), advanced breast cancer (53% response rate in 33 pts without significant chemotherapy for the target progression) and Hodgkin's disease (90% response rate after 4 weekly courses in 31 pts). Thus extensive pharmacological studies and ongoing clinical studies confirm that chemical modifications of the catharantine moiety of vinca alcaloid can lead to active agents with broader spectrum of activity and easily manageable side effects.

Cultured Nb rat lymphoma cells in endocrine and cancer research.

This review outlines the establishment, properties, and use of two lines of cultured Nb rat lymphoma cells. The cultured cells have retained important properties of the cancers of origin, such as dependency on prolactin for growth and a high sensitivity to antineoplastic Vinca alkaloids. The cultures have been useful for defining the hormonal dependency of the lymphomas in the animal and for studying the progression of the lymphomas from hormonal dependency to autonomy. A new, specific and highly sensitive in vitro bioassay for lactogenic hormones has been developed from one of the cultures. The use of the lymphoma cell cultures has revealed unsuspected pharmacological differences between the closely related, clinically useful antineoplastic Vinca alkaloids, vinblastine and vincristine. The lymphoma cell cultures are also useful tools for studying biochemical, cell cycle related events which follow the mitogenic stimulation of cells by a polypeptide growth factor.

Experimental antitumor activity of 5'-nor-anhydrovinblastine navelbine.

We have found that navelbine, a new semi-synthetic Vinca alkaloid analogue, is as active as vincristine on implanted murine tumors. It has a low cross-resistance with vincristine and vindesine.

Effects of vinblastine and 5-fluorouracil on human glioma and thyroid cancer cell monolayers and spheroids.

The effects of the two antitumor drugs vinblastine and 5-fluorouracil on the growth of the human tumor cell lines U-118 MG (glioma) and HTh-7 (thyroid cancer) were analyzed. The cells were cultured both as monolayers and as multicellular spheroids and exposed to vinblastine (0.1, 1.0, or 10 micrograms/ml) or 5-fluorouracil (10, 100, or 1000 micrograms/ml) for 15 min, 2 hr, or 24 hr. The drugs induced growth delays of the monolayers and delays in the outgrowth of cells from spheroids which were placed on cell-adhesive surfaces. Cell cultures exposed to sublethal drug doses showed a dose-dependent lag period followed by regrowth at normal growth rates. In all cases with vinblastine exposures, the spheroids seemed more resistant to the drug treatments than did the monolayer cultures. Much smaller differences were obtained after treatments with 5-fluorouracil. The three-dimensional arrangement of cells in spheroids giving rise to, e.g., nutrient and proliferation gradients may, to some extent, be responsible for the increased resistance. The spheroids were especially resistant to short treatments with vinblastine. This was probably due to penetration barriers.

[Influence of interferon on the toxic effect and antitumor activity of vinblastine in the combined therapy of metastatic Lewis carcinoma]. / Vliianie interferona na toksicheskii éffekt i protivoopukholevuiu aktivnost' vinblastina pri kombinirovannoi terapii metastaziruiushchei kartsinomy L'iuis.

Antitumour and antimetastatic effects of the combination of vinblastine (VLB) and L-cell interferon were examined. It is shown that mice with 3LL carcinoma are more sensitive to common toxic effect of VLB than intact animals. Interferon (IF) decreases the toxic effect of VLB in tumour-bearing mice, and thus provides a possibility to increase the total therapeutic dose of the cytostatic. The combination of VLB and IF showed a synergistic inhibitory effect on the development of carcinoma metastases and significantly increases the survival rate of the tumour-bearing mice. Neither synergistic nor additive antitumour effects of the combined therapy were observed on the primary tumour. IF suppresses the primary tumour growth more significantly when given by intratumoural injection. At the same time the inhibition of metastase development was more efficient with intraperitoneal injection of IF.

The effects of colchicine and vinblastine on memory in chicks.

Colchicine, injected bilaterally into the forebrain of day-old chicks at times before and after one-trial avoidance learning, produced transient amnesia for one to three hours after learning, that could not be accounted for as a perceptual or attentional defect. The amnesia was dose dependent and was produced only when injections occurred within a limited period before and after learning. No amnesia occurred when injections were given 120 min before or 60 min later than the learning trial, nor at times prior to the retrieval test. During the amnesic period, new learning could occur and be retrieved 15 min later. The amnesia could be overcome by retention-testing or by a new, related, learning experience before or up to 30 min after onset of amnesia. Control birds injected with saline or lumicolchicine, a biologically inactive derivative of colchicine, showed normal retention. Vinblastine sulphate, which also interrupts microtubular networks and hence axonal flow, had no amnesic properties. Colchicine injections had no effect on the levels of acetylcholinesterase, choline acetyltransferase, glutamic acid decarboxylase, and muscarinic acetylcholine receptors in the whole forebrain or in forebrain synaptosomes during the amnesic period. Nor did colchicine injections affect amino acid uptake and protein or glycoprotein synthesis before or during the amnesic period, although there was 10-20% inhibition of protein synthesis 5 h after injection. Thus over the amnesic period, there was no evidence of gross perturbation of brain function. Electron microscopy showed microtubules intact within 1 mm of the injection site 2.5 after injection. Oedema was found at this time in chicks injected with a high dose (100 micrograms) shown to disturb behaviour grossly, but not with a low dose (5 micrograms) which caused amnesia. Transient amnesia for one-trial avoidance learning is most probably caused by secondary effects of colchicine on nerve cell function. We suggest that the amnesic episode represents destruction of one of the stages of a multiple independent parallel process of memory consolidation.

Acute and protracted effects of vinblastine on odontoblasts and dentinogenesis in rat incisors.

The effects of a large dose of vinblastine sulfate (2 mg/kg body weight) on proliferating odontoblast precursors and secretory odontoblasts in the continuously growing rat incisor were studied. The rats were killed 6 h, 24 h, 3 d and 7 d after vinblastine injection. Most cells in the proliferating zone contained arrested mitoses, or had perished after 24 h. After 3 and 7 d, the odontoblasts derived from this zone were reduced in number, and showed altered cell shapes. The odontoblasts had produced irregular dentin. The secretory odontoblasts had displaced nuclei and altered cell shapes after 24 h. Those most affected were opposite early mineralized dentin. In some incisors the cells had perished. In the protracted experiments almost all the odontoblasts were changed and had produced abnormal dentin. In the early mineralized dentin area, accumulations of cells were present after 3 d, and osteodentin-like material after 7 d.

Screening of cytotoxic drugs for residual bone marrow damage.

Several cytotoxic drugs were tested for their ability to produce permanent residual damage to the bone marrow. A short course of the drug was given to BALB/c female mice, and the numbers of various types of bone marrow cells were determined at least two months later. Evidence of residual damage was found after administration of busulfan and 1,3-bis(chloroethyl)-1-nitrosourea, but not after administration of cyclophosphamide, 5-fluorouracil, 6-mercaptopurine, methotrexate, or vinblastine.