Consumption of latex from Euphorbia tirucalli L. promotes a reduction of tumor growth and cachexia, and immunomodulation in Walker 256 tumor-bearing rats

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia tirucalli L. is an African plant that grows well in Brazil. Individuals diagnosed with cancer frequently consume latex from E. tirucalli, dissolved in drinking water. In vitro studies confirm the antitumor potential of E. tirucalli latex, but in vivo evaluations are scarce.

AIM OF THE STUDY

To evaluate the effect of intake of an aqueous solution of E. tirucalli latex on tumor growth, cachexia, and immune response in Walker 256 tumor-bearing rats.

MATERIALS AND METHODS

Latex from E. tirucalli was collected and analyzed by LC-MS. Sixty male Wistar rats (age, 90 days) were randomly divided into four groups: C, control group (without tumor); W, Walker 256 tumor-bearing group; SW1, W animals but treated with 25 μL latex/mL water; and SW2, W animals but treated with 50 μL latex/mL water. Animals received 1 mL of latex solution once a day by gavage. After 15 d, animals were euthanized, tumor mass was determined, and glucose and triacylglycerol serum levels were measured by using commercial kits. Change in the body weight during tumor development was calculated, and proliferation capacity of tumor cells was assessed by the Alamar Blue assay. Phagocytosis and superoxide anion production by peritoneal macrophages and circulating neutrophils were analyzed by enzymatic and colorimetric assays. Data are analyzed by one-way ANOVA followed by Tukey's post-hoc test, with the significance level set at 5%.

RESULTS

The analysis of the latex revealed the presence of triterpenes. The ingestion of the latex aqueous solution promoted 40% and 60% reduction of the tumor mass in SW1 and SW2 groups, respectively (p < 0.05). The proliferative capacity of tumor cells from SW2 group was 76% lower than that of cells from W group (p < 0.0001). Animals treated with latex gained, on average, 20 g (SW1) and 8 g (SW2) weight. Glucose and triacylglycerol serum levels in SW1 and SW2 animals were similar to those in C group rats. Peritoneal macrophages and blood neutrophils from SW1 and SW2 animals produced 30-40% less superoxide anions than those from W group animals (p < 0.05), but neutrophils from SW2 group showed an increased phagocytic capacity (20%, vs. W group).

CONCLUSIONS

E. tirucalli latex, administered orally for 15 d, efficiently reduced tumor growth and cachexia in Walker 256 tumor-bearing rats. Decreased tumor cell proliferative capacity was one of the mechanisms involved in this effect. Further, the data suggest immunomodulatory properties of E. tirucalli latex. The results agree with folk data on the antitumor effect of latex ingestion, indicating that it may be useful as an adjunct in the treatment of cancer patients. For this, further in vivo studies in animal and human models need to be conducted.

Tumor development in rats and cancer cachexia are reduced by treatment with botryosphaeran by increasing apoptosis and improving the metabolic profile

AIMS

Cancer is a multifactorial disease characterized by an uncontrolled growth of cells that can lead to cachexia-anorexia syndrome. Botryosphaeran, a fungal (1 → 3)(1 → 6)-β-D-glucan produced by Botryosphaeria rhodina MAMB-05, has presented antimutagenic, antiproliferative, pro-apoptotic, hypoglycemic and hypocholesterolemic effects. This study evaluated the effects of botryosphaeran (30 mg/kg b.w./day) on tumor development and cachexia syndrome in Walker-256 tumor-bearing rats, and also the metabolic and hematological profiles of these animals.

MATERIALS AND METHODS

Male Wistar rats were divided into 3 groups: control (C), control tumor (CT) and control tumor botryosphaeran (CTB). On the first day, 1 × 10⁷ Walker-256 tumor cells were inoculated subcutaneously into the right flank of the CT and CTB rats, and concomitantly treatment with botryosphaeran (30 mg/kg b.w./day) started. After the 15th day of treatment, biological parameters, tumor development, cachexia, glucose and lipid profiles, hemogram and protein expression were analyzed.

KEY FINDINGS

Botryosphaeran significantly reduced tumor development (p = 0.0024) and cancer cachexia, modulated the levels of glucose, triglycerides and HDL-cholesterol, and corrected macrocytic anemia. Botryosphaeran also increased significantly the bax expression in the tumor tissue (p = 0.038) demonstrating that this (1 → 3)(1 → 6)-β-D-glucan is increasing the apoptosis of tumor cells. p53, p27, bcl-2, caspase-3 and Forkhead transcription factor 3a (FOXO3a) protein expression were similar among the groups.

SIGNIFICANCE

This study demonstrated that botryosphaeran was effective in decreasing tumor development and cachexia by direct and indirect mechanisms increasing apoptosis and improving the metabolic and hematological profiles.

Antitumor and genotoxic effects of lactoferrin in Walker-256 tumor-bearing rats

AIM

To investigate the influence of exogenous lactoferrin (LF) on tumor growth, energy and lipid metabolism of Walker-256 carcinosarcoma and to assess genotoxic effects of LF.

MATERIALS AND METHODS

The study was performed on Walker-256 tumor-bearing rats. Total lipids and phospholipids were determined by thin-layer chromatography. Comet assay was used to investigate the genotoxic effects of LF.

RESULTS

Daily i.p. administrations of exogenous LF at concentrations of 1 mg/kg and 10 mg/kg starting from the 4^th day after tumor transplantation suppressed growth of Walker-256 carcinosarcoma by almost 44%. After treatment with recombinant LF in both doses, the phospholipid composition of Walker-256 carcinosarcoma cells was changed (3-fold increase of phosphatidylethanolamine, 3.4-fold increase of phosphatidylcholine, and 1.8-fold increase of sphingomyelin, while the cardiolipin content decreased by 67%. Exogenous LF was not genotoxic for bone marrow cells (as assessed by the ratio of PCE/NCE, number of micronuclei) and peripheral blood lymphocytes (percentage of DNA in the tail of a comet) in Walker-256 carcinosarcoma-bearing rats.

CONCLUSION

Exogenous LF caused the inhibition of Walker-256 carcinosarcoma growth and a decrease in the microviscosity of plasma cell membranes, and exerted no genotoxicity toward bone marrow cells and peripheral blood of experimental animals.

Ruthenium complex exerts antineoplastic effects that are mediated by oxidative stress without inducing toxicity in Walker-256 tumor-bearing rats

The present study evaluated the in vivo antitumor effects and toxicity of a new Ru(II) compound, cis-(Ru[phen]₂[ImH]₂)²⁺ (also called RuphenImH [RuC]), against Walker-256 carcinosarcoma in rats. After subcutaneous inoculation of Walker-256 cells in the right pelvic limb, male Wistar rats received 5 or 10mgkg^-1 RuC orally or intraperitoneally (i.p.) every 3 days for 13 days. A positive control group (2mgkg^-1 cisplatin) and negative control group (vehicle) were also used. Tumor progression was checked daily. After treatment, tumor weight, plasma biochemistry, hematology, oxidative stress, histology, and tumor cell respiration were evaluated. RuC was effective against tumors when administered i.p. but not orally. The highest i.p. dose of RuC (10mgkg^-1) significantly reduced tumor volume and weight, induced oxidative stress in tumor tissue, reduced the respiration of tumor cells, and induced necrosis but did not induce apoptosis in the tumor. No clinical signs of toxicity or death were observed in tumor-bearing or healthy rats that were treated with RuC. These results suggest that RuC has antitumor activity through the modulation of oxidative stress and impairment of oxidative phosphorylation, thus promoting Walker-256 cell death without causing systemic toxicity. These effects make RuC a promising anticancer drug for clinical evaluation.

Yeast Microcapsule-Mediated Targeted Delivery of Diverse Nanoparticles for Imaging and Therapy via the Oral Route

Targeting of nanoparticles to distant diseased sites after oral delivery remains highly challenging due to the existence of many biological barriers in the gastrointestinal tract. Here we report targeted oral delivery of diverse nanoparticles in multiple disease models, via a "Trojan horse" strategy based on a bioinspired yeast capsule (YC). Diverse charged nanoprobes including quantum dots (QDs), iron oxide nanoparticles (IONPs), and assembled organic fluorescent nanoparticles can be effectively loaded into YC through electrostatic force-driven spontaneous deposition, resulting in different diagnostic YC assemblies. Also, different positive nanotherapies containing an anti-inflammatory drug indomethacin (IND) or an antitumor drug paclitaxel (PTX) are efficiently packaged into YC. YCs containing either nanoprobes or nanotherapies may be rapidly endocytosed by macrophages and maintained in cells for a relatively long period of time. Post oral administration, nanoparticles packaged in YC are first transcytosed by M cells and sequentially endocytosed by macrophages, then transported to neighboring lymphoid tissues, and finally delivered to remote diseased sites of inflammation or tumor in mice or rats, all through the natural route of macrophage activation, recruitment, and deployment. For the examined acute inflammation model, the targeting efficiency of YC-delivered QDs or IONPs is even higher than that of control nanoprobes administered at the same dose via intravenous injection. Assembled IND or PTX nanotherapies orally delivered via YCs exhibit remarkably potentiated efficacies as compared to nanotherapies alone in animal models of inflammation and tumor, which is consistent with the targeting effect and enhanced accumulation of drug molecules at diseased sites. Consequently, through the intricate transportation route, nanoprobes or nanotherapies enveloped in YC can be preferentially delivered to desired targets, affording remarkably improved efficacies for the treatment of multiple diseases associated with inflammation.

[INFLUENCE OF ANGIOPROTECTOR DRUGS ON THE EFFICACY OF CYTOSTATIC THERAPY (EXPERIMENTAL STUDY)]

The influence of angioprotector and endothelium-protector drugs pentoxifylline and unifuzol as components of supportive therapy on the efficacy of combined cytostatic treatment has been experimentally studied. It is established that pentoxifylline and unifuzol do not affect the antitumor and antimetastatic activity of doxorubicin and cyclophosphan with respect to Pliss lymphosarcoma and Walker 256 carcinosarcoma, and in some cases even potentiate the effect of cytostatic therapy.

Remodulating effect of doxorubicin on the state of iron-containing proteins, and redox characteristics of tumor with allowance for its sensitivity to cytostatic agents

The study was aimed at determining the changes of metal-containing proteins in blood serum and tumor tissue of animals with parental and doxorubicin-resistant strains of Walker-256 carcinosarcoma before and after the cytostatic administration. It has been shown that upon doxorubicin action the levels of total iron and transferrin in the tissues from the both groups of animals decreased while that of ferritine simultaneously increased with more pronounced pattern in the group of animals with resistant tumor strain. It has been shown that upon the action of doxorubicin in tumor tissue of animals with different sensitivity to the cytostatic there could be observed oppositely directed changes in the redox state of these cells that in turn determined the content of “ free iron” complexes, RO S generation and concentration of active forms of matrix metaloproteinase- 2 and matrix metaloproteinase-9, namely, the increase of these indexes in animals with parental strain and their decrease in animals with the resistant one. So, our study has demonstrated the remodulating effect of doxorubicin on the state of metal-containing proteins and redox characteristics of tumor dependent on its sensitivity to cytostatic, at the levels of the tumor and an organism. These data may serve as a criterion for the development of programs for the correction of malfunction of iron metabolism aimed at elevating tumor sensitivity to cytostatic agents.

Biochemical action of new complexes of ruthenium with quinolones as potential antitumor agents

BACKGROUND

The aim of the present study paper was to identify the role of reactive oxygen species (ROS) in apoptosis signaling mechanisms. We used for this purpose two ruthenium complex compounds based on that overproduce these reactive species by their metabolism thus manifesting their antitumor activity too.

MATERIALS AND METHODS

In vivo studies were performed in Walker 256 carcinoma-bearing Wistar rats treated with two ruthenium (III) (Ru(III)) complexes with -fluoroquinolones norfloxacin and ofloxacin. The treatment started 7 days after tumor grafting. We assayed the dynamics of apoptosis by flow-cytometry and the biochemical oxidative status parameters. The biological samples used were serum and whole-tumor tissues; the results were compared to the untreated control group.

RESULTS

The results showed an increase of apoptosis from 14.79% to 59.72% 14.79% to 59.72% in tumor cells treated with the most active combination, ruthenium complex with norfloxacin. We also noted an increase of the oxidative status and ROS production during treatment.

CONCLUSION

The newly-synthesized complexes are less toxic and their activity is based on the induction of oxidative stress.

METALLOPROTEINS DURING DEVELOPMENT OF WALKER-256 CARCINOSARCOMA RESISTANT PHENOTYPE

The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development ofdoxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage) in Walker-256 carc'inosarcoma tissue. We observed decreased serumferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases withfully developed resistance phenotype. Transferrin content showed changes opposite to that offerritin. During the development of resistance phenotype the tumor tissue also exhibited increased 'free iron' concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.

Optimal treatment opportunity for mTHPC-mediated photodynamic therapy of liver cancer

Photodynamic therapy (PDT) has been clinically used for liver cancer. The pharmacokinetics of a photosensitizer needs to be monitored so that PDT can be performed at the most favorable time and with the proper dose to increase the cure rate. As mTHPC is a fluorescent compound, we investigate its pharmacokinetics, distribution, and elimination in the rat orthotropic liver cancer model in order to confirm an optimal treatment opportunity of liver cancer PDT. After intravenous administration at a single dose of 300 μg/kg, mTHPC was extracted from tissue homogenates or plasma. Then, mTHPC concentrations were assessed by fluorescence spectroscopy and the data were processed with PK-GRAPH pharmacokinetic procedure. The plasma concentration-time profile of mTHPC showed a short distribution half-life (T½α = 0.082 h) and a relatively longer elimination half-life (T½β = 28.23 h), which quite fitted with a two-compartment model. The results of mTHPC tissue distributions showed that the highest drug accumulation was in tumor tissue, and successively decreased in liver, heart, spleen, muscle, and skin tissues. The drug distribution ratio of tumor to normal tissue reached the peak at 24 h after mTHPC administration. mTHPC was eliminated at a suitable rate in rat orthotropic liver cancer model, and there was no long-term accumulation of mTHPC in rat tissues. For PDT of orthotropic liver cancer, 24 h after mTHPC intravenous injection may be the optimal treatment time point, which might provide higher clinical efficacy and reduce side effects.

Topical treatment with Tong-Luo-San-Jie gel alleviates bone cancer pain in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal analgesic gel Tong-Luo-San-Jie (TLSJ) and its modifications are used in traditional Chinese medicine to manage cancer pain. However, its mechanisms are still unknown.

AIM OF THE STUDY

To investigate the effects and mechanisms of TLSJ gel on bone cancer pain in a rat model.

MATERIALS AND METHODS

A bone cancer pain rat model was established by inoculating Walker 256 rat carcinoma cells directly into the right tibial medullary cavity of Sprague-Dawley rats (150-170 g); Phosphate buffered saline (PBS) tibial inoculation was used as control. Cancer-bearing rats were treated twice a day with external TLSJ gel (0.5 g/cm(2)/day) or inert gel control for 21 day (n=10/group). Behavioral tests such as mechanical threshold and paw withdrawal latency (PWL) were carried out. Osteoclastic activities were determined and carboxyterminal pyridinoline cross-linked type I collagen telopeptides (ICTP) and bone-specific alkaline phosphatase (BAP) concentrations were detected with ELISA after treatment. Adverse effects were monitored, and biochemical and histological tests were performed in naïve rats treated with local TLSJ gel for six weeks.

RESULTS

TLSJ treatment significantly restored bone cancer-induced decrease of PWL and mechanical threshold compared to inert gel. It also decreased the level of blood serum ICTP and BAP and inhibited osteoclast activities. No adverse effects or abnormal biochemical and histological changes were detected after TLSJ treatment.

CONCLUSION

The present study shows that TLSJ significantly inhibits bone cancer-induced thermal and mechanical sensitization. It suggests that the gel may be useful in managing cancer pain and that it may act by inhibiting osteoclastic activity.

Naringin inhibits tumor growth and reduces interleukin-6 and tumor necrosis factor α levels in rats with Walker 256 carcinosarcoma

The flavonoid naringin is a polyphenolic compound that naturally occurs in citrus. Patients with cancer generally present features of malnutrition and cachexia. Levels of the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) are raised in patients with cancer. This study was designed to analyze the in vivo effect of naringin in the therapeutic treatment of rats bearing Walker 256 carcinosarcoma (W256). Rats were treated intraperitoneally with different doses of naringin (10, 25 and 35 mg/kg), for 50 days. At 25 mg/kg, naringin inhibited tumor growth by ~75%. With this treatment, TNF-α and IL-6 levels decreased (p<0.05) in comparison with the control. In addition, two rats presented complete tumor regression. Inhibition of tumor growth, survival increase and the reduction of TNF-α and IL-6 levels in rats bearing W256 treated with naringin strongly suggest that this compound has potential as an anticarcinogenic drug.

Fingolimod potentiates the effects of sunitinib malate in a rat breast cancer model

Most of the antiangiogenic strategies used in oncology principally target endothelial cells through the vascular endothelial growth factor (VEGF) pathway. Multiple kinase inhibitors can secondarily reduce mural cell stabilization of the vessels by blocking platelet-derived growth factor receptor (PDGFR) activity. However, sphingosine-1-phosphate (S1P), which is also implicated in mural cell recruitment, has yet to be targeted in clinical practice. We therefore investigated the potential of a simultaneous blockade of the PDGF and S1P pathways on the chemotactic responses of vascular smooth muscle cells (VSMCs) and the resulting effects of this blockade on breast tumor growth. Due to crosstalk between the S1P and PDGF pathways, we used AG1296 and/or VPC-23019 to inhibit PDGFR-β and S1PR1/S1PR3 receptors, respectively. We showed that S1PR1 and S1PR3 are the principal receptors that mediate the S1P chemotactic signal on rat VSMCs and that they act synergistically with PDGFR-β during PDGF-B signaling. We also showed that simultaneous blockade of the PDGFR-β and S1PR1/S1PR3 signals had a synergistic effect, decreasing VSMC migration velocity toward endothelial cell and breast carcinoma cell-secreted cytokines by 65-90%. This blockade also strongly decreased the ability of VSMCs to form a three-dimensional cell network. Similar results were obtained with the combination of sunitinib malate (a VEGFR/PDGFR kinase inhibitor) and fingolimod (an S1P analog). Sunitinib malate is a clinically approved cancer treatment, whereas fingolimod is currently indicated only for treatment of multiple sclerosis. Orally administered, the combination of these drugs greatly decreased rat breast tumor growth in a syngeneic cancer model (Walker 256). This bi-therapy did not exert cumulative toxicity and histological analysis of the tumors revealed normalization of the tumor vasculature. The simultaneous blockade of these signaling pathways with sunitinib malate and fingolimod may provide an effective means of reducing tumor angiogenesis, and may improve the delivery of other chemotherapies.

Antitumor effect of laticifer proteins of Himatanthus drasticus (Mart.) Plumel - Apocynaceae

ETHNOPHARMACOLOGICAL RELEVANCE

Himatanthus drasticus (Mart.) Plumel - Apocynaceae is a medicinal plant popularly known as Janaguba. Its bark and latex have been used by the public for cancer treatment, among other medicinal uses. However, there is almost no scientific research report on its medicinal properties.

AIM OF THE STUDY

The aim of this study was to investigate the antitumor effects of Himatanthus drasticus latex proteins (HdLP) in experimental models.

MATERIALS AND METHODS

The in vitro cytotoxic activity of the HdLP was determined on cultured tumor cells. HdLP was also tested for its ability to induce lysis of mouse erythrocytes. In vivo antitumor activity was assessed in two experimental models, Sarcoma 180 and Walker 256 carcinosarcoma. Additionally, its effects on the immunological system were also investigated.

RESULTS

HdLP did not show any significant in vitro cytotoxic effect at experimental exposure levels. When intraperitoneally administered, HdLP was active against both in vivo experimental tumors. However, it was inactive by oral administration. The histopathological analysis indicates that the liver and kidney were only weakly affected by HdLP treatment. It was also demonstrated that HdLP acts as an immunomodulatory agent, increasing the production of OVA-specific antibodies. Additionally, it increased relative spleen weight and the incidence of megakaryocyte colonies.

CONCLUSION

In summary, HdLP has some interesting anticancer activity that could be associated with its immunostimulating properties.

Oxidative photodamage induced by photodynamic therapy with methoxyphenyl porphyrin derivatives in tumour-bearing rats

The oxidative effects of photodynamic therapy with 5,10,15,20-tetrakis(4-methoxyphenyl) porphyrin (TMP) and Zn-5,10,15,20-tetrakis(4-methoxyphenyl) porphyrin (ZnTMP) were evaluated in Wistar rats subcutaneously inoculated with Walker 256 carcinoma. The animals were irradiated with red light (λ = 685 nm; D = 50 J/cm2; 15 min) 3 h after intra-peritoneal administration of 10 mg/kg body weight of porphyrins. The presence of free radicals in tumours after photodynamic therapy with TMP and ZnTMP revealed by chemiluminescence of luminol attained the highest level at 18 h after irradiation. Lipid peroxides measured as thiobarbituric-reactive substances and protein carbonyls, which are indices of oxidative effects produced on susceptible biomolecules, were significantly increased in tumour tissues of animals 24 h after photodynamic therapy. The levels of thiol groups and total antioxidant capacity in the tumours were decreased. The activities of antioxidant enzymes superoxide dismutase and glutathione peroxidase were also increased in tumour tissues after photodynamic therapy. Increased levels of plasma lipid peroxides as well as changes in the levels of erythrocyte antioxidant enzyme activities suggest possible systemic effects of photodynamic therapy with TMP and ZnTMP.

Immunohistochemical study for the expression of Bcl-2 family proteins in Walker 256 carcinosarcoma cells under the influence of cytostatic drugs

Immunohistochemical study was performed to evaluate the expression of Bcl-2 family proteins (Bcl-2, Bax, and Bad) in Walker 256 carcinosarcoma cells after implantation into the thigh muscle of male Wistar rats (10(6) cells). The experiment was conducted under conditions of spontaneous tumor development and individual or combined treatment with melatonin and cyclophosphamide. The use of melatonin as monotherapy or in combination with cyclophosphamide was followed by a significant decrease in Bcl-2 expression in carcinosarcoma cells. The Bcl-2/Bax and Bcl-2/Bad ratio was significantly reduced under these conditions (particularly after combined treatment with cytostatic drugs). These changes were accompanied by a significant (by 93.61%) decrease in the volume of transplantable tumor on day 14. Daily treatment with melatonin was accompanied by significant changes in the structure of Walker 256 carcinosarcoma. It was manifested in the formation of connective tissue septa and pseudofollicles.

Protection of multiple antioxidants Chinese herbal medicine on the oxidative stress induced by adriamycin chemotherapy

Adriamycin is an effective anthracycline anti-tumor antibiotic. However, the clinical use of adriamycin has been restricted by its serious side effects. Some reports indicated that the side effects of adriamycin could cause systemic injury, in which reactive oxygen species (ROS) play an important role. ROS are a large family of oxygen free radical and non-free radical active oxygen-containing molecules, including superoxide radical, hydrogen peroxide and hydroxyl radical, which contribute to oxidative stress. Although antioxidant treatment is a promising method to prevent the side effects, protection by a single antioxidant is limited. The Chinese herbal medicine ANTIOXIN is a multiple antioxidant that can effectively block oxidative stress. It was hypothesized that ANTIOXIN could effectively reduce the side effects of adriamycin. A rat tumor model with a transplanted tumor in the liver was treated with adriamycin and ANTIOXIN was used as a protection. Oxidative stress and antioxidant enzymes were evaluated. The results showed that adriamycin chemotherapy increased the level of malondialdehyde (MDA), nitrogen oxide (NO) and decreased the activities of total superoxide dismutase (T-SOD), manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione (GSH) and total antioxidant capacity (TAC). Adriamycin chemotherapy also decreased the expression of Bcl-2, increased the expression of iNOS and cell apoptosis in the liver and kidney. Multiple antioxidants ANTIOXIN had an antagonistic effect on these changes and significantly decreased the mortality of the experimental rats. These data demonstrated that adriamycin chemotherapy could cause oxidative stress to the whole body, on which multiple antioxidants based on the theory of 'multiple antioxidant chain' had effective protection.

(99m)Tc-MIBI imaging for prediction of therapeutic effects of second-generation MDR1 inhibitors in malignant brain tumors

The aim of this study was to explore whether (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) is suitable to elucidate multidrug resistance and prediction of potentiation of antitumor agents by second-generation MDR1 inhibitors (PSC833, MS-209) in malignant brain tumors in rat. Malignant tumor cells (RG2 and C6 gliomas, Walker 256 carcinoma) were incubated with low dose vincristine (VCR) to induce multidrug resistance. MTT assay demonstrated a significant increase of surviving fractions in VCR-resistant sublines compared to those of drug-naive cells. Reverse transcriptase polymerase chain reaction revealed higher expression of MDR1 mRNA in VCR-resistant cells than drug-naive cells in each line. Volume distribution (V(d)) of (99m)Tc-MIBI was negatively correlated with MDR1 mRNA expression among drug-naive and VCR-resistant cells. MDR1 inhibitors decreased surviving fractions and increased V(d) of (99m)Tc-MIBI significantly in VCR-resistant sublines, whereas MDR1 mRNA expression was unchanged. These findings indicate that (99m)Tc-MIBI efflux was functionally suppressed by MDR1 inhibitors. Autoradiographic images of (99m)Tc-MIBI revealed higher uptake in drug-naive cells at basal ganglia compared with VCR-resistant cells at the opposite basal ganglia of rats. Oral administration of the second-generation MDR1 inhibitors significantly increased (99m)Tc-MIBI accumulation of both tumors. Therapeutic effects of VCR with or without the MDR1 inhibitors were also evaluated autoradiographically using (14)C-methyl-L-methionine ((14)C-Met) and MIB-5 index. (14)C-Met uptake and MIB-5 index of both tumors treated with VCR following the MDR1 inhibitor treatment significantly decreased compared with tumors treated with VCR alone. Analysis of (99m)Tc-MIBI accumulation is considered informative for detecting MDR1-mediated drug resistance and for monitoring the therapeutic effects of MDR1 inhibitors in malignant brain tumors.

[Characteristics of polyamine biosynthesis regulation and tumor growth rate in hormone-dependant grafted breast tumors of mice and rats]

Effect of the inhibitors of polyamines biosynthesis on completely or partially hormone-dependant breast tumors (mouse Ca755 carcinoma and Walker W-256 carcinosarcoma) is essentially special: in contrary to hormone-dependant tumors, this effect may be not only breaking but stimulating as well. Change-over from one to another mode of reaction is conditioned, most probable, by hormonal status, which is determined by one or another estral cycle phase. Biochemical mechanisms of this change-over are closely connected with polyamines metabolism, namely the degree of polyamines (especially spermine) interconvertion and physiological reactivity level of the system controlling expression of ornithin-decarboxilase. At that, the first of these pathways is predominant for completely hormone-dependant Ca755 and the second one -for partially hormone-dependant W-256.

Preventative ibandronate treatment has the most beneficial effect on the microstructure of bone in experimental tumor osteolysis

We investigated the effect of ibandronate on three-dimensional (3-D) microstructure and bone mass in experimentally induced tumor osteolysis. Walker carcinosarcoma cells were implanted into the left femur of female rats that received 26-day ibandronate pretreatment followed by continued therapy or ibandronate posttreatment only. A tumor-only group received isotonic saline. At endpoint, excised femurs were scanned using microcomputed tomography (microCT) to assess bone volume density, bone mineral content, trabecular number/thickness, and separation for cortical plus trabecular bone or trabecular bone alone. Compared with the nonimplanted right femur, bone volume and surface density and trabecular number and thickness were reduced in the distal left femur following tumor cell implantation. microCT analysis revealed greater cortical and trabecular bone mineral content in the preventative and interventional (pre-post tumor) ibandronate group, and the interventional (post-tumor) ibandronate group, versus the tumor-only group. Bone volume density was significantly higher in pre-post and post-tumor groups compared to the tumor-only group. After preventative and interventional ibandronate, bone volume density and trabecular thickness were 13% and 60% greater, respectively, than in the post-tumor treatment group. 3-D microCT images confirmed microstructural changes. We conclude that combined interventional and preventative ibandronate preserves bone strength and integrity more than intervention alone.

[Effect of plant biocomposites based on Georgian tea "per se" and in combination with cisplatin on Walker carcinosarcoma W-256 and Guerin's carcinoma growth rate in rats]

Green tea biocomposite had effectivey hampered the growth of rat Walker W-256 carcinoma and in less extent rat Guerin's carcinoma. Black tea biocomposite had not practically influenced on Guerin's carcinoma growth. The biocomposite from green tea and extract from red vine rind and lemon suppressed at the level of tendency the growth of rat Walker W-256 carcinoma. The biocomposite from green tea and extract from red vine rind had hampered only Guerin's carcinoma growth and at the tendency had increased the growth of W-256 carcinosarcoma growth. This biocomposite increased also considerably the therapeutic efficiency of cisplatin on Guerin's carcinoma. Studed vegetable biocomposites posesses antiinflammatory and antioxidant properties.

Novel polymeric microspheres containing norcantharidin for chemoembolization

Chemoembolization has been found to be a potentially effective method of treating certain types of cancer. It involves arterial embolization of a tumor, in combination with simultaneous or subsequent local delivery of chemotherapeutic agents. In this study, PLGA-alginate microspheres were evaluated for their potential application in chemoembolization. Norcantharidin, which possesses anti-tumor properties, was used to investigate the application of drug-containing microspheres for chemoembolization. The release profiles of alginate, PLGA and PLGA-alginate microspheres were markedly different in phosphate buffered saline, with the composite microspheres showing the most appropriate release rate for chemoembolization. Burst effect decreased while particle size increased with increasing proportion of alginate in the PLGA-alginate microspheres. PLGA-alginate microspheres containing norcantharidin were effective in destroying the cancer cells used in this study. The growth inhibitory effect was concentration and time dependent. These microspheres also exhibited excellent embolization and therapeutic effects on rats with transplanted tumors.

Synthesis of (1,4)-naphthoquinono-[3,2-c]-1H-pyrazoles and their (1,4)-naphthohydroquinone derivatives as antifungal, antibacterial, and anticancer agents

A series of (1,4)-naphthoquinono [3,2-c]-1H-pyrazoles and their (1,4)-naphthohydroquinone derivatives 2-7 were synthesized and evaluated for antifungal, antibacterial, and anticancer activities. The structure-activity relationship of these compounds was studied and the results show that the compound 2b exhibited in vitro antifungal activity against Candida albicans and Cryptococcus neoformans, and also possessed antibacterial profile against Klebsiella pneumoniae and Escherichia coli whereas 1c showed anticancer activity against Walker 256 Carcinosarcoma in rats.

Photodynamic Therapy of Walker Tumors by Multiple Laser Irradiation

OBJECTIVE

Photodynamic therapy of Walker tumor after subcutaneous administration of 5-ALA solution using a multiple laser irradiation scheme was monitored by the fluorescence imaging technique to investigate the effectiveness of 5-ALA-PDT.

BACKGROUND DATA

Photodynamic therapy (PDT) is a localized cancer treatment based on the selective uptake and retention of photosensitizer at the tumoral level and on the activation of the photosensitizer by a specific wavelength of light, aiming to induce cytotoxic reactions. As a new photosensitizer, the heme precursor 5- aminolevulinic acid has been introduced recently for photodynamic therapy of tumors and precancerous lesions of the skin. It has been shown that the efficacy of topical 5-ALA-PDT is limited for deeper skin tumor by the depth of 5-ALA penetration through the skin. Oral or systemic administration of ALA or the use of different irradiation schemes may improve tumor response to PDT.

METHODS

Laser irradiation parameters used in this study were lambda = 635 nm, P = 3 mW, t(exp) = 300 sec, and three sessions. The fluorescence was excitated by monochromatic light of 405 nm. The temporal behavior of PpIX fluorescence was studied by processing and analyzing the fluorescence images acquired just after applying 5-ALA, just before and just after three laser irradiations.

RESULTS

The results demonstrate that PpIX is highly selective for tumors areas and a re-accumulation of PpIX appears between laser irradiations. During laser irradiation, the PpIX fluorescence intensity decreases rapidly, reflecting the photodegradation of PpIX.

CONCLUSIONS

In conclusion, the use of a multiple laser irradiation scheme, for the activation of reaccumulation of Pp IX (with three steps) is effective for photodynamic therapy of Walker tumor.

A pilot study of antitumor effect of gallium ethylenediaminetetramethylene phosphonate [Ga(III)-EDTMP] in tumor-bearing rats

The inhibitory effects of gallium ethylenediamine-N,N,N',N'-tetrakismethylene phosphonate [Ga(III)-EDTMP] was studied on a malignant tumor and metastatic bone lesion model induced with Walker carcinosarcoma 256 (WCS 256) in Wistar rats weighing 120 to 135 g. A water-soluble chelate, Ga(III)-EDTMP, was prepared for injection in a tumor-bearing model. Radiographic analysis at 14 days indicated that the bone invasion and osteolysis were markedly reduced in animals treated with Ga(III)-EDTMP. The calculated tumor inhibitory rates were 33.16+/-0.38% at a dosage of 5 mg/kg and 47.75+/-0.74% at 10 mg/kg. Biochemical markers such as serum calcium decreased by 23% (P<.05) and by 31% (P<.01) at dosages of 5 mg/kg and 10 mg/kg, respectively, whereas serum alkaline phosphatase (ALPase) activity decreased by 47% (P<.01) and 69% (P<.01) at the 2 dosages.

Hepatic artery infusion of antisense oligodeoxynucleotide and lipiodol mixture transfect liver cancer in rats

AIM: To study the distribution and stability of antisense oligodeoxynucleotide (ASODN) in Walker-256 cells and their distribution in liver, lung and kidney tissues after being infused alone or mixed with lipiodol via hepatic artery in a rat liver tumor model.

METHODS: 5’-Isothiocyananate (FITC)-labeled vascular endothelial growth factor (VEGF) ASODN was added into Walker-256 cell culture media. Its distribution in cells was observed by fluorescence microscope at different time points. Walker-256 carcinosarcoma was transplanted into Wistar rat liver to establish a liver cancer model. 5’-FITC-labeled VEGF ASODN mixed with (mixed group, n = 6) or without (TAI group, n = 6) ultra-fluid lipiodol was administrated via hepatic artery. Frozen samples of liver, lung and kidney tissue were taken from rats after 1, 3 and 6 d, respectively. The distribution of ASODN was observed under fluorescent microscope.

RESULTS: ASODN could enter cytoplasm within 2 h and nuclei within 6 h. Accumulation of ASODN reached the peak point in nuclei at 12 h, and then disappeared gradually. No fluorescence could be seen in cells at 48 h. In vivo experiment, on d 1 and 3 the fluorescence staining in liver was stronger in mixed group than in TAI group and more fluorescence could be detected in lung and kidney in TAI group than in mixed group. On d 6, no fluorescence could be detected in TAI group, but faint fluorescence could be seen in mixed group. ASODN could be seen in cancer cells and normal hepatic cells. In mixed group, ASODN was mainly distributed in liver tumor tissues.

CONCLUSION: ASODN can transfect Walker-256 cells. ASODN mixed with lipiodol infusion via hepatic artery can be used in the treatment of HCC.

Mycophenolate mofetil attenuates Walker's tumor growth when used alone, but the effect is lost when associated with cyclosporine

PURPOSE

To investigate the effect of mycophenolate mofetil on Walker's carcinosarcoma, without versus with the growth and regression of cyclosporine.

METHODS AND RESULTS

Wistar rats received water (control), MMF, and/or CsA-N 1 day before tumor inoculation. On day 10, tumor volume (TV) was lower among MMF (10.3 +/- 2.8 cm(3)) than control rats (14.9 +/- 4.2 cm(3), P <.05), and similar to that in CsA-N (13.9 +/- 3.0 cm(3)). However, tumor weight (TW) was significantly lower in MMF (5.2 +/- 2.0 g) than CsA-N (8.8 +/- 2.1g) or control hosts (7.3 +/- 2.0 g, P < or =.01). Growth was inhibited by MMF (-28.2%). In experiment II, CsA-N, MMF + CsA-N, or water were introduced 1 day before tumor inoculation. On day 10, TV and TW were similar for MMF + CsA-N as compared to CsA-N and control animals. In experiment III, water or MMF was introduced on the day 4 after tumor inoculation. On day 10, tumor growth are TW in the MMF group was similar to, that in the controls.

CONCLUSIONS

MMF produces an anti-tumoral effect against Walker's carcinosarcoma. However, this inhibitory effect was lost when MMF was used in combination with CsA-N or administered in the presence of a well- established tumor.

Metabolic and hematological effects of dietary supplementation with arginine on rats bearing ascitic Walker 256 tumor

The notion of using supplementary quantities of arginine for nutritional support in patients with cancer has been evaluated not only as supplement intake of nitrogen substrate but also for its immunopharmacological effects capable of improving the patient's prognosis. The aim of the present study is to evaluate the effects of dietary supplementation with arginine on metastatic dissemination, amino acid metabolism, hematological functions of rats with Walker 256 ascitic tumor. Animals were inoculated intraperitoneally with approximately 4 million cells. Nutritional solutions containing 4 or 6% arginine or just a control diet without added arginine, were administered to the animals via esophagic gavages. The rate of metastasis was lower in animals supplemented with arginine at 4 and 6%. Amino acid metabolism was stimulated in tumor-bearing animals after receiving 4 or 6% arginine, demonstrated by significant increase of arginine, ornithine, citrulline, proline and histidine levels in the blood (p < or = 0.001) when compared to the control diet group. Anemia was less severe in tumor-bearing animals that received arginine supplementation. The findings suggest that arginine supplementation at 6% may have a beneficial effect on to the host, besides its pharmacological action.

The monitoring of the accumulation of protoporphyrin IX in Walker tumours by subcutaneous administration of delta-aminolevulinic acid

Photodynamic therapy with protoporphyrin IX induced by delta-aminolevulinic acid (ALA) is mainly applied for the treatment of human superficial skin cancer. In this paper we present our study on photodynamic therapy (PDT) of the implanted Walker tumours using subcutaneous administration of ALA to improve the availability of ALA in the skin. We determined the accumulation and localization of protoporphyrin IX (PpIX) after subcutaneous administration of different concentrations of ALA in a physiological saline solutions, using fluorescence imaging technique. The results obtained indicate that PpIX accumulation depends on the concentration of ALA. The temporal behavior of PpIX fluorescence has shown a clear demarcation of tumoural zone depending on the post-administration time and the administrated concentration of the ALA solution. Further studies are needed to confirm these encouraging results and to define the PDT protocols using subcutaneous administration of ALA solution

Target distribution of magnetic albumin nanoparticles containing adriamycin in transplanted rat liver cancer model

BACKGROUND

Liver cancer is one of the most common diseases around the world. The aim of this study was to verify the effect of magnetic field application on target distribution of nanoparticles in transplanted rat liver cancer model and to find out a new method for the treatment of malignant liver tumor.

METHODS

Seven days after the establishment of the model, the abdomen of the rat was exposed through a midline abdominal incision. A cannula was inserted into the gastro-duodenal artery. In the experimental group (12 rats), the tumor tissue was exposed to the magnetic field for 30 minutes. Magnetic albumin nanoparticles containing adriamycin or at an equal dose of free adriamycin (0.5 mg/kg) were injected into the hepatic artery. After the magnetic field was removed, the rat was immediately sacrificed. An equal dose of nanoparticles in absence of the magnetic field served as control (12 rats). Tissues of tumor, nontargeted sites of the liver, heart, kidney, lung, spleen, stomach and small intestine were analyzed for gamma-counts and examined histologically.

RESULTS

In the experimental group, the radioactivity of tumor tissue was 8.7 times that of liver tissue. In the control group, the radioactivity of tumor tissue was 2.8 times that of normal liver tissue. The radioactivity of the lung was reduced more significantly in the experimental group than in the control group. No significant difference in the kidney, heart, spleen, small intestine and stomach was observed between the experimental group and control group. And over 80% of the injected nanoparticles distributed in the liver.

CONCLUSIONS

In the presence of magnetic field, magnetic albumin nanoparticles may accumulate in tumor tissues, of which the radioactivity can increase to 8.7 times that of normal liver. Even if the magnetic field is not applied, magnetic albumin nanoparticles in tumor tissues still increase to 2.8 times that of normal liver tissues. These findings indicate that normal organs in the presence of magnetic field are less exposed to chemotherapeutic drugs.

Enhanced antitumor efficacy on hepatoma-bearing rats with adriamycin-loaded nanoparticles administered into hepatic artery

AIM: To investigate the antitumor activity of adriamycin (ADR) encapsulated in nanoparticles (NADR) and injected into the hepatic artery of hepatoma-bearing rats.

METHODS: NADR was prepared by the interfacial polymerization method. Walker-256 carcinosarcomas were surgically implanted into the left liver lobes of 60 male Wistar rats, which were divided into 4 groups at random (15 rats per group). On the 7th day after implantation, normal saline (NS), free ADR (FADR), NADR, or ADR mixed with unloaded nanoparticles (ADR + NP) was respectively injected via the hepatic artery (i.a.) of rats in different groups. The dose of ADR in each formulation was 2.0 mg/kg body weight and the concentration was 1.0 mg/mL. Survival time, tumor enlargement ratio, and tumor necrosis degree were compared between each group.

RESULTS: Compared with the rats that received NS i.a., the rats that received FADR or ADR + NP acquired apparent inhibition on tumor growth, as well as prolonged their life span. Further significant anticancer efficacy was observed in rats that received i.a. administration of NADR. Statistics indicated that NADR brought on a more significant tumor inhibition and more extensive tumor necrosis, as compared to FADR or ADR + NP. The mean tumor enlargement ratio on the 7th day after NADR i.a. was 1.106. The mean tumor-bearing survival time was 39.50 days. Prolonged life span ratio was 109.22% as compared with rats that accepted NS.

CONCLUSION: Therapeutic effect of ADR on liver malignancy can be significantly enhanced by its nanopaticle formulation and administration via hepatic artery.

Cancer cachexia and tumor growth reduction in Walker 256 tumor-bearing rats supplemented with N-3 polyunsaturated fatty acids for one generation

In this study we investigated the effect of lifelong supplementation of the diet with coconut oil (CO, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids, PUFAs) on tumor growth, animal survival, and metabolic indicators of cachexia in adult rats. Female Wistar rats were supplemented with CO or FO prior to mating and then throughout pregnancy and gestation, and then the male offspring were supplemented from weaning until 90 days of age. Then they were inoculated subcutaneously with Walker 256 tumor cells. Tumor weight at 14 days in control rats (those fed standard chow) was approximately 20 g. These animals displayed cancer cachexia, which was characterized by loss of weight, hypoglycemia, hyperlacticidemia, hypertriacylglycerolemia, and depletion of glycogen stores. Supplementation of the diet with CO did not change these parameters, except that there was a smaller decrease in serum triacylglycerol concentration. Supplementation of the diet with FO significantly decreased tumor growth (by approximately 60%), increased survival (50% at 30 days postinoculation vs. 30% in the controls and 13.5% in the CO group), and prevented the fall in body weight. Furthermore, FO supplementation partly abolished the fall in serum glucose, totally prevented the elevation in serum lactate concentrations, partly prevented the hypertriacylgylcerolemia, and preserved tissue glycogen stores. Lifelong consumption of FO, rich in n-3 PUFAs, protects against tumor growth and cancer cachexia and improves survival.

The effect of triethyllead on the motile activity of walker 256 carcinosarcoma cells

The effect of triethyllead (TriEL) on the morphology and motile activity of Walker 256 carcinosarcoma cells was investigated. It was found that both 2 and 5 microM TriEL affected the cellular motility in a dose- and time-dependent manner. Initially, 2 microM TriEL caused the formation of blebs instead of lamellipodia at the front of some cells and stimulated the migration of Walker cells, but after 2 hours of 2 microM TriEL treatment, a reduction of cellular motility was observed. In the presence of 5 microM TriEL, Walker 256 carcinosarcoma cells rounded up, and their rate of movement was reduced. Moreover, the treatment of Walker carcinosarcoma cells with TriEL caused the disruption of microtubules and affected the F-actin distribution at both concentrations. At a concentration of 2 microM TriEL, the actin staining intensity was greatest in the tail of front-tail polarised blebbing cells and the actin layer was very thin at the leading edge. The control cells showed linear cortical F-actin distribution and somewhat less intense cytoplasmic staining at the same TriEL concentration. Cells treated with 5 microM TriEL showed an under-membrane pattern of actin distribution.

Naproxen, clenbuterol and insulin administration ameliorates cancer cachexia and reduce tumor growth in Walker 256 tumor-bearing rats

Cancer cachexia is characterized by anorexia and intense peripheral catabolism. We examine the potential benefits of combination of different anabolic agents such as insulin and clenbuterol associated to prostaglandin synthesis inhibitor (naproxen) on tumor growth, cachexia and renal function in Walker 256 tumor-bearing rats (WK). Groups were separated into WK, and WK with naproxen (WK N) or naproxen plus clenbuterol (WK NCb) or naproxen plus clenbuterol plus insulin (WK NCbI). Treatment begins at the 4th day after tumor inoculation, at the 14th day they were killed, glycemia, lacticidemia, glycogen content from liver, soleus and gastrocnemius muscles, tumor mass, body weight and kidney function were determined. Glycemia and glycogen content were reduced and lacticidemia increased in WK (p<0.05) as compared to control rats. The glycogen content recovered in all treated groups. Tumor weight was significantly reduced by the different treatments. At the 14th weight change (carcass-initial body weight) in the control increased by 38% and in the WK -2%. Naproxen treatment (WK N) induced an increased by 14%. The inclusion of clenbuterol (WK NCb) and insulin (WK NCbI) by 38 and 41%, respectively. Mean glomerular filtration rate (GFR) increased in the WK (p<0.05) as compared to control, but in the WK NCb the GFR was similar to control. Our results suggest that naproxen is able to reduce tumor growth and its association with insulin and clenbuterol induce mass weight gain and recovery energy fuel.

Biological activity of bacterial lectins and their molecular complexes with heterocyclic bis-adducts

A new convenient method for the preparation of heterocyclic bis-adducts: of imidazole, benzimidazole, uracile with 1,1,1-trifluoro-2-bromo-2-chloroethane is described. The reactions are catalysed by the 18-crown-6-complex. The critical toxicity and antitumour activity of saprophytic strains Bacillus genus (B. subtilis 668 IMV and B. polymyxa 102 KSU) extracellular lectins were studies. It was discovered that these substances apply to a few toxic preparations and have a expression antitumour action on the tumours: Walker carcinosarcoma 256, Pliss' lymphosarcoma and Sarcoma 45. The new molecular complexes were created with bacterial lectins and the same heterocyclic-bis-adducts of unsubstituted benzimidazole and 6-methyluracile. A strongly antitumour effect of these complexes has been discovered: of growth relaxation of Pliss' lymphosarcoma tumour mass was 62.5-82.01%.

Effects of combined selenium and vitamin E administration on DNA in Walker tumor bearing Wistar rat exposed to cytostatic acute treatment

Previous studies have showed that organic Se and Vitamin E have a significant protective effect when administered in combination with cytostatics. This paper reports the investigation on effects of mixed administration Orgasel 50 and Vitamin E in Wistar rat with experimentally induced Walker tumor under acute cytostatic treatment, with emphasis on two aspects: a) the influence of antioxidants upon liver unscheduled DNA biosynthesis under cytostatic (Lomustin) acute aggression; and b) the potential improvement of cytostatic effects by antioxidants treatment in tumor. Two lots of animals were used: lot 1 - Orgasel 50 and Vitamin E administered 7 days before the initiation of tumor induction and lot 2 - the antioxidants were concomitantly administered with tumor cell inoculation. The Walker tumor (an epithelial carcinoma) cells were subcutaneously injected (5 x 10(6) cells/0.5 ml in isotonic saline solution); the first tumor nodules appeared in 4 days; the tumor has reached the appropriate dimensions in 12 days. The unscheduled DNA biosynthesis caused by Lomustin in rat liver as well as the replicative DNA biosynthesis taking place in Walker tumor cells were assessed radioisotopically by measuring the uptake of 3H-Thymidine (200 microCi / 100 g.b.w.). Our observations regarding the role of antioxidant treatment suggest: 1) a benefic effect on DNA alkylant-induced lesions, expressed by a decrease in the level of 3H-Thymidine uptake in liver and, 2) an increase of the inhibitory activity of cytostatic on DNA replication biosynthesis in tumor cells, suggested by lower 3H-Thymidine incorporation in tumor cells. The most significant results were showed in both analyzed tissues, when the Orgasel 50 + Vitamin E administration begins at the same time with the tumor cell inoculation. These findings clearly show the organic Se salts and Vitamin E constitute a valuable adjuvant in anticancer medication, increasing the interest for the application of these antioxidants in cancer therapy and prevention.

Synthesis and pharmacological studies of some 2-t-amino and 2,3-di-t-amino substituted 1,4-naphthoquinones and related compounds

Series of 2-t-amino and 2,3-di-t-amino substituted-1,4-naphthoquinones have been synthesised from corresponding 1,4-naphthoquinones by reaction with secondary amines. The compounds have been evaluated for their broad spectrum antimicrobial, antiviral and anticancer activity. In the preliminary screening results 8a and 9a have shown profile of an antimicrobial agent.

Efficacy and tolerability of an aminopterin-albumin conjugate in tumor-bearing rats

The antifolate aminopterin (AMPT) was developed before methotrexate (MTX), but was not clinically established or generally used due its increased toxicity compared to MTX. Recently, we reported on the increased metabolism of albumin conjugates such as methotrexate-albumin (MTX-SA) in malignant tumors and the feasibility of using albumin as a carrier for drug targeting. Consequently, AMPT was covalently bound to serum albumin (AMPT-SA) at a 1:1 molar ratio. Biodistribution, tolerability and efficacy of this novel conjugate were studied in Walker-256 (W-256) carcinoma-bearing rats. As compared to native albumin, the same biodistribution and plasma clearance were found for AMPT-SA, which achieved 20.1% tumor uptake (estimated uptake per g tumor 6.4%) within 24 h after i.v. administration in rats. In a randomized study, AMPT-SA, repeatedly i.v. injected, was compared with low-molecular-weight AMPT. Depending on the molar concentration, the maximum tolerated dose (MTD) of AMPT covalently bound to SA was twice that of unbound AMPT (three repeated injections of 1.0 mg AMPT-SA/kg body weight versus three repeated injections of 0.5 mg AMPT/kg body weight; p=0.0006). Efficacy was studied at the level of the MTD and MTD/2, and demonstrated that AMPT-SA was significantly more active. At the MTD/2 in W-256 carcinoma-bearing rats, AMPT-SA achieved a 100% volume reduction and an optimal volume reduction during treatment/control (T/C) of 8.3% compared to a 53% volume reduction of AMPT and a T/C of 16.5% (p=0.032). Tumor relapses were reduced and occurred later in the AMPT-SA group (two tumor recurrences for AMPT-SA versus seven for AMPT; p=0.05). In this comparative study, the AMPT-SA conjugate showed high antitumor activity in vivo and a favorable toxicity compared to low-molecular-weight AMPT. These effects are attributed to the albumin carrier which seems to be an effective tool for selective tumor drug targeting.

[Disorders of blood rheology in Walker's carcinosarcoma-256 and in cyclophosphamide treatment of rats]

Tumor process development in rats inoculated with cellular suspension of transplantable Walker's carcinosarcoma-256 involved enhanced thickening of blood on day 7. Treatment with 20 mg/kg cyclophosphamide, thrice a day, every other day, retarded tumor process and brought hemorheologic indices further down, at the same time. Similar treatment of intact rats with cyclophosphamide caused hemorheologic disorders too.

Pharmacokinetic and pharmacodynamic evaluation of intermittent versus continuous alendronate administration in rats

We studied the differences in pharmacokinetics and pharmacodynamics of the same dose of alendronate administered subcutaneously as intermittent bolus injection or continuous infusion in rats. Two rat models of bone disease were applied. Bone cancer was produced by intratibial inoculation of Walker carcinosarcoma cells, and a model of augmented bone resorption was produced by vitamin D(3) treatment of rats that had undergone thyroidparathyroidectomy. Higher amounts of alendronate were found in bones and in internal organs after bolus drug administration as compared with continuous infusion. Drug effects on plasma calcium levels and on urine calcium excretion were similar in both modes of alendronate administration. Results of the study indicate that the pharmacokinetics (disposition) of alendronate is administration-dependent. The total amount found in bone does not directly represent the amount of alendronate that is pharmacologically active at the site of action in the bone and that affects bone remodeling. The findings suggest that there is no pharmacodynamic advantage for continuous infusion of alendronate. It is concluded that the preferred mode of administration should be selected according to secondary clinical criteria (like incidence of adverse effects and convenience of administration).

[Cytotoxicity of beta-lapachone, an naphthoquinone with possible therapeutic use]

beta-lapachone (beta-lap) is a lipophilic o-naphthoquinone isolated from the bark of the lapacho tree. Initial observations proved its capability for inhibiting growth of Yoshida tumor and Walker 256 carcinosarcoma. beta-Lap redox-cycling in the presence of reductants and oxygen yields "reactive oxygen species" (ROS: O2-, OH and H2O2) which cytotoxicity led to assume its role in beta-lap activity in cells. beta-Lap inhibited DNA synthesis in Trypanosoma cruzi as well as topoisomerases I and II, poly(ADP-ribose) polymerase (PARP) in different cells. These enzymes are essential for maintaining DNA structure. beta-Lap inhibited growth of a large variety of tumor cells including epidermoid laringeal cancer, prostate, colon, ovary and breast cancer and also different types of leukemia cells. Advances in knowledge of apoptosis ("programmed cell death") and necrosis provided useful information for understanding the mechanism of beta-lap cytotoxicity. Thiol-dependent proteases (Calpaine), kinases (e.g. c-JUN NH2-terminal kinase), caspases and nucleases are involved in beta-lap cytotoxicity. These enzymes activity, as well as ROS production by beta-lap redox-cycling, would be essential for beta-lap cytotoxicity. Diaphorase and NAD(P)H-quinone reductase, which catalyse beta-lap redox-cycling and ROS production, seem to play an essential role in beta-lap activity. On these grounds, clinical applications of beta-lap have been suggested.

New approach to the adoptive immunotherapy of Walker-256 carcinosarcoma with activated macrophages combined with photodynamic therapy

Experiments were performed on five batches of Wistar inbred rats with Walker-256 carcinoma receiving sole (PDT, MAK) or combined therapy (PDT + MAK-A; PDT + MAK-B); the control batch (HBSS) consisted of animals with untreated tumors. The results were as follows: a) the sole treatment (PDT, MAK) gave survival rates between 37.7 and 47.5%, b) the "combined" therapy in five doses increased significantly (70.8%) the survival rate of tumor bearing rate as well as the rate of complete regression (82.1%). The cell-mediated immunity test and histopathological as well as the electron microscopy observations were in full agreement with the results above. Summing up, these results demonstrate that "combined" photodynamic therapy with intra- and peritumoral MAK infusion stimulated cell-mediated antitumoral activity, increased survival rates and reduces incidence of Walker-256 carcinoma in rat model.

[Experimental chemotherapy of malignant tumors in combination with short-term general hypoxia]

The effect of hypoxy on chemotherapy with emoxyl, 5-fluorouracil and bleomycin which are characterized by different affinities with oxygen has been investigated. In an experiment using 96 rats, each weighing 180 g, subcutaneously inoculated with Walker's carcinosarcoma and carcinoma. PC-1, combined use of chemotherapy and hypoxy was followed by a significant inhibition of tumor growth rate, against a background of significant drop in survival due to the increased toxic effect of the drugs. Therefore, hypoxy cannot be recommended for modifying chemotherapy of tumors irrespective of drug affinity with oxygen.

Characteristics of tissue distribution of various polysaccharides as drug carriers: influences of molecular weight and anionic charge on tumor targeting

Using the Walker 256 model for carcinosarcoma-bearing rats, we intravenously administered 5 polysaccharide carriers with various molecular weights (MWs) and electric charges and tested for their plasma and tissue distribution. Two carriers, carboxymethylated-D-manno-D-glucan (CMMG) and CMdextran (CMDex), showed higher plasma AUC than the other carriers tested, namely, CMchitin (CMCh), N-desulfated N-acetylated heparin (DSH), and hyaluronic acid (HA). This was consistently found to be true over the range of MWs tested. For CMDex, the maximum value of plasma AUC was obtained when the MW exceeded 150 kDa. As for the anionic charge, CMDex (110-180 kDa) with a degree of substitution (DS) of the CM groups ranging from 0.2 to 0.6, showed maximum plasma AUC values. Twenty-four hours after administration, the concentration of CMDex (180-250 kDa; DS: 0.6-1.2) in tumors was more than 3% of dose/g--approximately 10-fold higher than those observed with CMCh, DSH and HA. Doxorubicin (DXR) was bound to these carriers via a peptide spacer, GlyGlyPheGly (GGFG), to give carrier-GGFG-DXR conjugates (DXR content: 4.2-7.0 (w/w)%), and the antitumor effects of these conjugates were tested with Walker 256 carcinosarcoma-bearing rats by monitoring the tumor weights after a single intravenous injection. Compared with free DXR, CMDex-GGFG-DXR and CMMG-GGFG-DXR conjugates significantly suppressed tumor growth, while the CMCh-GGFG-DXR, DSH-GGFG-DXR, and HA-GGFG-DXR conjugates in a similar comparison showed weak tumor growth inhibition. These findings suggest that the antitumor effect of the carrier-DXR conjugates was related to the extent with which the carriers accumulated in the tumors.

Effect of iron chelator, hydroxyl radical scavenger and cytochrome P450 inhibitors on the cytotoxicity of cisplatin to tumor cells

BACKGROUND

Iron catalyzed reactive oxygen metabolites (ROM) are important mediators in cisplatin (CP)-induced nephrotoxicity, and cytochrome P450 (CYP) is the major source of this iron. Iron chelators, hydroxyl radical scavengers and CYP inhibitors have shown marked protection.

MATERIAL AND METHODS

This study was designed to determine whether these agents affect the tumoricidal efficacy of CP to LLC-WRC 256 tumor cells.

RESULTS

CP was cytotoxic to the tumor cells in a dose and time dependent manner. Iron chelator, hydroxyl radical scavenger and CYP inhibitors did not reduce the cytotoxic effect of CP. Exposure of the tumor cells to CP did not increase the catalytic iron release and the generation of hydroxyl radical. Both CYP activity and content in the tumor cells were less than 10% of that in the rat liver.

CONCLUSION

We speculate that iron chelator, hydroxyl radical scavenger and CYP inhibitors do not alter the antitumor efficacy of CP.

[Pharmacological effects of arginine supplementation in rats with Walker 256 solid tumor]

The effects of diet arginine supplementation for those with cancer are controversial. We evaluate the effects of dietetic supplementation with arginine over body weight, growth of tumor, metastatic dissemination, surviving time, amino acid metabolism, haematological changes of the rats with Walker 256 solid tumor. Intragastrical solutions with arginine at 4% and 6%, a standard diet (control) were administered to the animals. The supplementation with arginine was associated with a lower weight gain during the study period (p < 0.05). Surviving time of the rats with solid tumor did not vary significantly between the groups. The rate of metastase was lower in animals with Walker 256 solid tumor supplemented with arginine. The amino acid metabolism was estimulate in the animals after arginine supplementation at 4% and 6%, demonstrated by significant increases in blood levels of arginine, ornitine, citruline, proline and histidine when compared to the control group. Anaemia was less severe in the rats with Walker 256 solid tumor that received arginine supplementation. The results suggest that arginine 6% supplementation may have pharmacologic effect in rats with Walker 256 solid beyond the nutritional one.

Association between histomorphometry and biochemical markers of bone turnover in a longitudinal rat model of parathyroid hormone-related peptide (PTHrP)-mediated tumor osteolysis

Advanced tumor osteopathy is characterized by abnormal bone turnover. Using a rat model of parathyroid hormone-related peptide (PTHrP)-mediated tumor osteolysis, the aim of the present study was to define the sequential changes in, and the association between, biochemical and histomorphometric indices of bone metabolism during the early stages of developing tumor osteopathy. Eight-month-old Wistar rats (n = 48) were subcutaneously inoculated with either 2 x 10(6) cells of the Walker carcinosarcoma 256, or saline on day 0, and treated with either saline or the bisphosphonate ibandronate until killing on day 8. Serum calcium (sCa), alkaline phosphatase (sTAP), and osteocalcin (sOC) and urinary calcium (uCa), deoxypyridinoline (uDPD), and pyridinoline (uPYD) were measured daily. In a second semilongitudinal experiment (n = 70), the number of osteoclasts and osteoblasts (N.Oc, N.Ob), trabecular bone volume (BV/TV), and osteoid volume (O.Ar) were assessed by histomorphometry. In untreated tumor-bearing animals, osteoclast numbers increased by 74% on day 3 (5.4 +/- 2.4 vs. 3.1 +/- 1.5/mm(2), p < 0.05), and trabecular bone volume fell by 24% on day 4 (12.5 +/- 2.0 vs. 15.8 +/- 1.2%, p < 0.05). Both time course and magnitude of these changes were closely reflected by an increase in uDPD (0.46 +/- 0.14 vs. 0. 31 +/- 0.15 nmol/12 h, p < 0.05) and uPYD on day 4 (1.44 +/- 0.25 vs. 1.03 +/- 0.3 nmol/12 h, p < 0.05), sCa (3.8 +/- 0.52 vs. 3.0 +/- 0. 13 mmol/L, p < 0.01), and uCa (0.13 +/- 0.08 vs. 0.03 +/- 0.01 mmol/12 h, p < 0.001) on day 6, and sTAP (254 +/- 127 vs. 120 +/- 40 U/L, p < 0.001) on day 7 (mean +/- SD), whereas sOC remained unchanged until day 8. When combining the results of the two experiments, a high correlation was found between the number of osteoclasts and the urinary excretion of PYD (r = 0.91) and DPD (r = 0.89). Treatment with ibandronate delayed hypercalcemia, abolished hypercalciuria, and accelerated bone resorption. We conclude that osteoclast activation is an early event in PTHrP-mediated osteolysis, which is closely reflected by the renal excretion of pyridinium cross-links of type I collagen. Therefore, specific biochemical markers of collagen breakdown may be useful as early indicators of developing tumor osteopathy.

Enhancing the uptake of chemotherapeutic drugs into tumors using an "artificial lymphatic system"

This paper presents findings from uptake studies to evaluate the ability of an "artificial lymphatic system" (ALS) to enhance large and small molecular weight drug transport into solid tumors and the therapeutic effect of the additional drug on their growth. These studies also served to test the effectiveness of an implantable multidrain ALS. Walker 256, Neuroblastoma, and Sarcoma dual-tumor models were used to evaluate the effect of ALS aspiration on the uptake of 3F8 monoclonal antibody, and doxorubicin. A tumor shrinkage experiment using Walker 256 dual tumors was used to evaluate the efficacy of an implantable ALS with cyclophosphamide chemotherapy. Drug uptake significantly increased in all aspirated tumors; 3F8 uptake was enhanced 37.4% in the Walker and 93.1% in the Neuroblastoma tumor lines (p<0.05). Doxorubicin uptake increased 23.2% in Sarcoma tumor (p<0.05). The shrinkage study demonstrated that one-drain aspirated tumors shrank 90% faster (p<0.01) than control tumors, while three-drain aspirated tumors shrank 123% faster than control tumors (p<0.01).

Enhancement of 5-fluorouracil anabolism by methotrexate and trimetrexate in two rat solid tumor models, Walker 256 carcinosarcoma and Novikoff hepatoma, as evaluated by 19F-magnetic resonance spectroscopy

Although 5-fluorouracil (5-FU) is one of the most effective single agents in treating solid tumors, its low effectiveness as a single agent has led to development of a number of modulators intended to enhance its therapeutic effectiveness. Of these, methotrexate (MTX) and trimetrexate (TMTX) have been shown to have synergistic anticancer activity with 5-FU. The effect of these two drugs on the uptake and the intratumoral metabolism of 5-FU was studied in two rat tumor models using 19F-nuclear magnetic resonance spectroscopy: on excised samples of Walker 256 carcinosarcoma and noninvasively (in vivo) in Novikoff hepatoma. In the rats bearing the Walker 256 tumor, a 4-hr pretreatment with MTX showed the maximal increase in the rate of conversion from 5-FU to its fluorinated nucleotides/nucleosides. In the rats bearing the Novikoff hepatoma, both modulators increased the amounts of cyctotoxic anabolites of 5-FU, but at the doses administered, the cumulative amounts of 5-FU anabolites formed after MTX were significantly higher than those formed after TMTX or after saline control. On the other hand, the increase in the levels of the fluorinated nucleotides/nucleosides after TMTX peaked at a later time. The possible significance of these findings is that timing of administration of a modulator is important because it affects both transport and metabolism of 5-FU. The two modulators studied, both antifolates, act differently on transport and on metabolism: MTX affects both, whereas TMTX, at the level studied, appears to affect predominantly the metabolic process. In addition, significant differences exist between tumor models. These data suggest possible mechanisms and processes that should be studied further in humans, using these noninvasive pharmacokinetic imaging methods for monitoring 5-FU targeting and metabolism.

Polyurethanes based on dihydroxamic acids. Synthesis, chemical characterization, and biological activity

A series of segmented polyurethanes based on polyethylene oxide/polycaprolactone diol, isophorone diisocyanate, and dihydroxamic acids were synthesized and characterized. Biocompatibility and antitumoral activity were in vivo tested on Wistar male rats and Wistar rats affected with Walker 256 carcinosarcoma, respectively. The effect of dihydroxamic acid structure on the biological properties was determined. A better antitumoral response of the polyurethanes containing aliphatic dihydroxamic segment compared with those which resulted using terephthaloyl dihydroxamic acid was evidenced. With increasing polymer chain polyethylene oxide content the antitumoral activity was also enhanced. Some attempts on the in vitro biodegradation of above polyurethanes were also performed.