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We studied the expression of Nrf2 transcription factor and antioxidant system proteins in drug-resistant murine leukemia strains P388 in vivo, as well as the redox status of cells under conditions of induced oxidative stress. Immunoblotting and real-time PCR showed that the cyclophosphamide-resistant strain P388 (P388/CP) exhibits Nrf2-mediated drug resistance. Cells of the P388/CP strain are characterized by high expression of Nrf2, which leads to a significant increase in the expression of ARE genes and antioxidant system proteins, as well as to the effective maintenance of redox homeostasis under conditions of induced oxidative stress. Taking into account the important role of Nrf2 overexpression in reducing the effectiveness of chemotherapy in patients with different leukemias, the P388/CP strain can be of great interest as a model in the development of new drugs for the treatment of malignant neoplasms., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

The efficiency of combinations of cytostatics cisplatin and adriamycin with antioxidant sodium 3-(3'-tert-butyl-4-hydroxyphenyl)propyl thiosulfate (TS-13), and nitric oxide (NO) donor NaNO 2 was evaluated on two drug-resistant strains of leukemia P388 with changed redox-status of cells. Simultaneous use of both NO donor and TS-13 in combinations with the cytostatics did not increase the efficiency of therapy. In addition, antioxidant activity of TS-13, NaNO 2 , and their combinations was studied by the method of luminol-dependent chemiluminescence on the model systems with the use of the homogenized cells of sensitive strain and two drug-resistant strains of leukemia P388. It was shown that TS-13 and NO donor produced opposite effects: TS-13 decreased, while NO donor increased the content of free radicals in the model system. Combinations of antioxidant TS-13 and NO donor should be used with consideration for the redox-status of tumor treated., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Combined treatment of murine leukemia P388 with doxorubicin and platinum(IV)-nitroxyl complex ВС118 administered in low doses improved efficiency of treatment (cure of 83% of animals) without increasing toxicity., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Preclinical study of therapeutic properties of an innovative drug Doxorubicin-NPh (doxorubicin in the form of ultrafine suspension of phospholipid liposomes) in comparison with free doxorubicin (Doxorubicin-Teva) and protected doxorubicin (Caelyx) was performed on transplanted murine tumor models. All these drugs were efficient in Ca755 breast carcinoma model (tumor growth inhibition ≈100%, increase in lifespan 90.6-114.3%). In P388 lymphocytic leukemia and LLC lung carcinoma, advantages of the protected doxorubicin by the benefit/risk ratio (width of therapeutic interval) were demonstrated: Caelyx>Doxorubicin-NPh>Doxorubicin-Teva. Doxorubicin-NPh and Caelyx exhibited similar therapeutic activity in the LLC model, especially when administered 3 times with 3-day intervals; for Doxorubicin-Teva, the optimal interval between the injections was 7 days.

Cyclophosphamide is an inert prodrug converted into 4-hydroxycyclophosphamide (OHCP) by hepatic hydroxylation. OHCP is in equilibrium with its tautomeric aldophosphamide (ALDO). From ALDO, the cytotoxic active metabolites are formed enzymatically by phosphodiesterases; these are the alkylating metabolite phosphoramide mustard (PAM) and the proapoptotic aldehyde 3-hydroxypropanal (HPA). PAM damages the DNA by alkylation; HPA amplifies the thereby induced apoptosis. The generally accepted view that acrolein, which is believed to be formed in the formation of PAM by β-elimination from ALDO would be mainly responsible for the toxicity of cyclophosphamide, has to be revised because no acrolein is formed in the systemic circulation of patients after cyclophosphamide administration. It is shown that not acrolein, but OHCP itself is the true toxic metabolite of cyclophosphamide. Toxicity tests with OHCP and PAM were carried out, which demonstrated that OHCP unfolds its toxicity, not as a carrier of PAM but is toxic itself by reacting with nucleophilic groups of macromolecules, for example, thiol groups of membrane proteins. Further experiments demonstrate that the toxicity of oxazaphosphorine cytostatics may be drastically reduced if the formation of the pharmacologically active metabolite ALDO bypasses the formation of OHCP. Toxicity experiments in mice with S-ethanol-cyclophosphamide (SECP) that hydrolyzes to OHCP show that SECP is as toxic as OHCP, whereas the thiazolidine of ALDO, which hydrolyzes to ALDO bypassing OHCP is 7-9 times less toxic without loss of antitumor activity.

The production of two new heterocyclic peptide isomers, catenulobactins A (1) and B (2), in cultures of Catenuloplanes sp. RD067331 was significantly increased when it was cocultured with a mycolic acid-containing bacterium. The planar structures and absolute configurations of the catenulobactins were determined based on NMR/MS and chiral-phase GC-MS analyses. Catenulobactin B (2) displayed Fe(III)-chelating activity and moderate cytotoxicity against P388 murine leukemia cells.

Context: Sechium edule (Jacq.) Sw. (Cucurbitaceae) is used in ethnomedicine, but the diversity of the varietal groups of this species has not often been considered. This is important because we previously reported that different variety of species exhibit different activities across different tumor cell lines., Objective: This study investigates the chemical composition and biological activities of extracts obtained from S. edule var. nigrum spinosum., Materials and Methods: The leukemia P388 cell line and mononuclear bone marrow cells (MNCBMs) were treated with the extract at a concentration ranging from 40 to 2370 μg/mL for cytotoxicity and viability assays. CD-1 mice were treated with 8-5000 mg/kg extract and monitored every hour for the first 24 h and subsequently for seven days for signs of toxicity (LD 50 ). In addition, the chromatographic profile of the extract was determined by HPLC., Results: The extract inhibits the proliferation of both P388 cells and MNCBMs, with IC 50 values of 927 and 1911 μg/mL, respectively, but reduced the viability and induced the apoptosis of only leukemia cells. The LD 50 was higher than 5000 mg/kg, and this concentration did not alter the blood chemistry or cell count but doubled the mitotic index in the bone marrow. The HPLC showed the presence of cucurbitacins, phloridzin, naringenin, phloretin, apigenin, and gallic, chlorogenic, vanillic, p-hydroxybenzoic, caffeic, and p-coumaric acids., Discussion and Conclusion: Sechium edule var. nigrum spinosum contains bioactive compounds that explain the antiproliferative and nutraceutical activities, and its lack of physiological side effects constitutes an added value to a widely consumed vegetable.

We studied the effectiveness of cyclic hydroxamic acid CHA-5 against drug-resistant and multidrug-resistant murine P388 leukemia strains. More than 60% mice receiving transplantation of rubomycin-resistant leukemia P388 strain survived after CHA-5 monotherapy; combined therapy with CHA-5 and cisplatin was also highly effective. Vincristine-resistant tumor was highly sensitive to combined treatment with CHA-5 and cyclophosphamide. It should be emphasized that standard antitumor agents were used in very low doses in combination therapy and CHA-5 significantly potentiated their effect.

Fractions of water soluble and alkali soluble polysaccharides, as well as fucogalactan, a water soluble polysaccharide, and xylomannan, an alkali soluble polysaccharide, were isolated from the Ganoderma lucidum submerged mycelium. When administered orally, the polysaccharides showed antitumor activity in vivo on murine models of solid tumors. Xylomannan and fucogalactan showed the highest antitumor activity. Sensitivity to xylomannan was more pronounced in adenocarcinoma Ca755 as compared to the T-cell lymphocytic leukemia P388. The antitumor activity of the water soluble polysaccharides total fractions from the mycelium and fruiting bodies of the G. lucidum strain was almost identical. The maximum antitumor effect of the mycelium water soluble polysaccharides total fraction was observed with the use of the daily dose of 2 mg/kg.

Ophiocordyceps sinensis and Cordyceps militaris metabolites showed a high potential in the treatment of tumors as well as some other diseases. Antitumor properties of O. sinensis and C. militaris submerged mycelium were investigated. It was found that the O. sinensis dry biomass in a dose of 50 mg/kg administered once a day to the mice with subcutaneously inoculated P388 lympholeucosis lowered the tumor growth by 65% vs. 54% for the C. militaris dry biomass. The water extract of O. sinensis submerged culture however accelerated the growth of the P388 lympholeucosis tumor node in the mice almost two times, compared to the control. A greater caution in using this fungus as a source of biologically active substances is required since unwanted tumor-stimulating effects can arise.

The antiproliferative potential of a crude extract from the chayote hybrid H-837-07-GISeM® and its potential for apoptosis induction were assessed in leukaemic cell lines and normal mouse bone marrow mononuclear cells (BM-MNCs). The extract strongly inhibited the proliferation of the P388, J774, and WEHI-3 cell lines (with an IC50 below 1.3 μg·mL(-1)), reduced cell viability, and induced apoptotic body production, phosphatidylserine translocation, and DNA fragmentation. However, the extract had no effect on BM-MNCs. We postulate that these properties make the extract a good candidate for an anti-tumour agent for clinical use.

Four new cembrane-type diterpenes; numerosol A-D (1-4); along with a known steroid; gibberoketosterol (5); were isolated from the Taiwanese soft coral Sinularia numerosa. The structures of these metabolites were determined by extensive analysis of spectroscopic data. Gibberoketosterol (5) exhibited cytotoxicity against P-388 (mouse lymphocytic leukemia) cell line with an ED50 of 6.9 μM.

Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

Purpose: Pluronic block copolymers are potent sensitizers of multidrug resistant cancers. SP1049C, a Pluronic-based micellar formulation of doxorubicin (Dox) has completed Phase II clinical trial and demonstrated safety and efficacy in patients with advanced adenocarcinoma of the esophagus and gastroesophageal junction. This study elucidates the ability of SP1049C to deplete cancer stem cells (CSC) and decrease tumorigenicity of cancer cells in vivo., Experimental Design: P388 murine leukemia ascitic tumor was grown in BDF1 mice. The animals were treated with: (a) saline, (b) Pluronics alone, (c) Dox or (d) SP1049C. The ascitic cancer cells were isolated at different passages and examined for 1) in vitro colony formation potential, 2) in vivo tumorigenicity and aggressiveness, 3) development of drug resistance and Wnt signaling activation 4) global DNA methylation profiles, and 5) expression of CSC markers., Results: SP1049C treatment reduced tumor aggressiveness, in vivo tumor formation frequency and in vitro clonogenic potential of the ascitic cells compared to drug, saline and polymer controls. SP1049C also prevented overexpression of BCRP and activation of Wnt-β-catenin signaling observed with Dox alone. Moreover, SP1049C significantly altered the DNA methylation profiles of the cells. Finally, SP1049C decreased CD133(+) P388 cells populations, which displayed CSC-like properties and were more tumorigenic compared to CD133(-) cells., Conclusions: SP1049C therapy effectively suppresses the tumorigenicity and aggressiveness of P388 cells in a mouse model. This may be due to enhanced activity of SP1049C against CSC and/or altered epigenetic regulation restricting appearance of malignant cancer cell phenotype.

The molecule known as SF2575 from Streptomyces sp. is a tetracycline polyketide natural product that displays antitumor activity against murine leukemia P388 in vivo. In the SF2575 biosynthetic pathway, SsfS6 has been implicated as the crucial C-glycosyltransferase (C-GT) that forms the C-C glycosidic bond between the sugar and the SF2575 tetracycline-like scaffold. Here, we report the crystal structure of SsfS6 in the free form and in complex with TDP, both at 2.4 Å resolution. The structures reveal SsfS6 to adopt a GT-B fold wherein the TDP and docked putative aglycon are consistent with the overall C-glycosylation reaction. As one of only a few existing structures for C-glycosyltransferases, the structures described herein may serve as a guide to better understand and engineer C-glycosylation., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: The search for new, innovative methods to treat all types of diseases, especially cancer-related ones, is a challenge taken by pharmaceutical companies and academic institutions. The use of conjugates containing widely-known and widely-used bioactive substances is one of the ways to solve this problem. Research into drug binding with macromolecular carrier systems has joined the search for new therapeutic strategies., Methods: The main goal of this paper is the potential offered by the use of fibrinogen derivatives as an antileukemic drug carrier. Physicochemical properties of the obtained conjugate were analyzed, characterizing alterations in relation to the starting carrier and analyzing biological implications. The intraperitoneally (i.p.) inoculated P388 mouse leukemia model for in vivo studies was used., Results and Conclusions: Conjugates consisting of a fibrinogen derivative with a covalently bound anticancer drug were developed. Carrier preparation and a conjugate synthesis in aqueous solution were formulated, as well as purification of the conjugate was performed. The study showed that the survival of leukemia mice treated with FH-MTX conjugate was indeed significantly longer than survival in both untreated animals (control) and mice treated with unbound MTX. A significant increase in the antileukemic activity of MTX conjugated with hydrolysed fibrinogen was observed as compared with the unconjugated drug. Reported data suggest that hydrolysed fibrinogen can serve as a carrier molecule for the MTX drug with the aim of enhancing its antileukemic activity., General Significance: Conjugates consisting of a fibrinogen derivative with a covalently bound anticancer drug seem to be a promising anticancer drug.

On the basis of the results of in-silico predictions and in an effort to extend our structure-activity relationship studies, the aromatic nitrogen mustard 2-[4-N,N-bis(2-chloroethyl) amino-phenyl]butanoic acid (2-PHE-BU) was synthesized and conjugated with various steroidal alcohols. The resulting steroidal esters were evaluated for their in-vivo toxicity and antileukemic activity in P388-leukemia-bearing mice. The new derivatives showed significantly reduced toxicity and marginally improved antileukemic activity compared with free 2-PHE-BU. Nevertheless, they did not prove to be superior either to the template steroidal ester used for in-silico predictions or to previously synthesized steroidal esters of aromatic nitrogen mustards. The results obtained indicate that in-silico design predictions may guide the design and synthesis of new bioactive steroidal esters, but further parameters should be considered aiming at the discovery of compounds with optimum activity.

Apoptosis-associated speck-like protein (ASC) is a bipartite adaptor molecule that participates in inflammation and apoptosis. ASC silencing has been observed in a significant proportion of human cancers. Here, we examined the role of ASC overexpression in the metastasis of the P388D1 murine lymphoma cell line to the liver, lung, spleen and kidney. First, we determined that the P388D1 cells express ASC. Then, ASC overexpression in P388D1 was achieved by transfecting pEGFP-ASC-C2 into the P388D1 cells. Furthermore, after the ASC-overexpressing P388D1 cells were injected into DBA/2 mice through the vena caudalis, their metastasis to the lung and the liver was significantly reduced in the pEGFP-ASC-C2-transfected group. These data indicate that ASC overexpression affects the in vivo metastatic properties of P388D1 cells., (Copyright © 2011 John Wiley & Sons, Ltd.)

Artificial neural networks (ANNs) have been applied for the quantitative structure-activity relationships (QSAR) studies of antitumor activity of acridinone derivatives. Molecular modeling studies were performed with the use of HyperChem and Dragon computer programs and molecular geometry optimization using MM+ molecular mechanics and semi-empirical AM1 method, and several molecular descriptors of agents were obtained. A high correlation resulted between the ANN predicted antitumor activity and that one from biological experiments for the data used in the testing set of acridinones was obtained with correlation coefficient on the level of 0.9484. Moreover, the sensitivity analysis indicated that molecular parameters describing geometrical properties as well as lipophilicity of acridinone derivative molecule are important for acridinones antitumor activity.

A new sesquiterpene hydroquinone (1) was isolated from a deep sea sediment derived fungus, Phialocephala sp.. Its structure and stereochemistry were established on the basis of spectroscopic data and optical rotation. This compound was tested for cytotoxicity against P388 (murine leukemia cell) and K562 (human leukemia cell) cell lines, and displayed strong cytotoxic effects with IC50 value of 0.16 and 0.05 micromol x L(-1), separately.

Two geranylated and methylated flavonol derivatives, macarhizinoidins A (1) and B (2), along with a known phenolic compound methyl 4-isoprenyloxycinnamate (3), have been isolated from the methanol extract of the leaves M. rhizinoides. The structures of these compounds were identified based on their spectroscopic data. On cytotoxic evaluation against murine leukemia P-388 cells, compounds 1-2 showed IC50 values of 11.4 and 13.9 microM, respectively, while compound 3 was inactive.

Purpose: The purpose of the present study was the investigation of antileukemic effect of amiodarone in leukemia P388 BDF1 bearing mice and its genotoxic and cytostatic effect in cultured normal human lymphocytes., Methods: Leukemia P388 was used in this study. BDF1 mice were used for chemotherapy evaluation in vivo. The antitumor activity was assessed by the oncostatic parameter T/C, representing the increase of life span of drug-treated animals vs. controls. Lymphocyte cultures were used to study the genotoxic and cytostatic effect in vitro, expressed by enhanced sister chromatid exchange (SCE) and reduced proliferation rate indices (PRIS)., Results: Amiodarone was found to exert antileukemic potency against leukemia P388 bearing mice at all three different treatment schedules used, yielding T/C values of 155%, 163% with one cure and 230%. In the in vitro cytogenic experiments, significant increase of SCE rates by amiodarone was observed at 0.2 μM, while at the same concentration significant suppression of PRIS was achieved., Conclusion: According to the National Cancer Institute (NCI), a compound is characterized as potential chemotherapeutic deserving further evaluation if it produces T/C values≥125%. On the other hand the SCE assay has predictive value as a clinical assay for drugs exhibiting a strong correlation between cell killing and induction of SCEs. Further studies are warranted to clarify the structure-activity relationship of amiodarone.

2-Amino-1-arylidenaminoimidazoles, a novel class of orally (po) active microtubule-destabilizing anticancer agents, were synthesized. The compounds were designed from a hit compound identified in a drug discovery platform by using cancer cell-based high throughput screening assay. Selective synthesized compounds exerted cell cytotoxicity against human cancer cells. The underlying mechanisms for the anticancer activity were demonstrated as interacting with the tubulins and inhibiting microtubule assembly, leading to proliferation inhibition and apoptosis induction in the human tumor cells. Furthermore, two compounds showed in vivo anticancer activities in both po and intravenously (iv) administered routes and prolonged the life spans of murine leukemic P388 cells-inoculated mice. These new po active antimitotic anticancer agents are to be further examined in preclinical studies and developed for clinical uses.

Erythropoietin (EPO) is a protein widely used against drug induced anemia at cancer patients. Irinotecan (CPT-11) is a genotoxic topoisomerase I inhibitor. We investigated the genotoxic, cytostatic and cytotoxic effects of EPO in the presence and in the absence of CPT-11 in human lymphocytes in vitro and in ascites cells of P388 leukemia in vivo. The levels of genotoxicity, cytostaticity and cytotoxicity were evaluated in human lymphocytes in vitro, and in P388 ascites tumor cells in vivo. The results show that EPO is not genotoxic. Unlikely to EPO, CPT-11 caused severe genotoxic, cytostatic and cytotoxic effects by significantly increasing SCE levels and decreasing PRI and MI values in peripheral lymphocytes in vitro and in P388 ascites tumor cells in vivo. Adding EPO in human lymphocyte cultures in vitro and in P388 leukemia bearing mice in vivo in the presence of CPT-11 decreased SCEs levels and increased PRIs and MIs were observed compared with cells treated either in vitro or in vivo with CPT-11 alone, which shows that EPO protected cells from the toxic action of CPT-11. EPO's protective action on human peripheral lymphocytes in vitro and P388 cells in vivo from the topoisomerase I inhibitor CPT-11, lead us to propose it as a geno- and cytoprotective agent., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Two erythrodiol triterpene fatty esters, 3beta-dodecanoyl erythrodiol (1) and 3beta-tetradecanoyl erythrodiol (2), were isolated from Scorzonera mongolica. Their structures were elucidated on the basis of IR, MS and extensive 2D NMR spectroscopic analysis. Compound 1 was identified to be a new compound and 2 was confirmed to be a new natural compound. Their antitumor effects in vitro were evaluated with MTT and SRB assays, but compounds 1 and 2 only showed moderate cytotoxicities on A-549 cell line.

Lysosomal proteases are actively involved in pathogenesis of cancer progression. Alterations in proteases and their inhibitors interaction were suggested to be implicated in the processes of tumor invasion and metastasis. Among proteases connected with malignant growth, cysteine cathepsins B and L and aspartic cathepsin D play the main role in the tumor development. The present study was designed to investigate activity of cathepsins B, L and D activity in the development and treatment of murine experimental leukemias and to determine the correlation of these proteases with tumor malignancy and the chemotherapy effect. P-388 leukemia was characterized by a more aggressive development and unfavorable prognosis than L1210/1 leukemia. The activity of cathepsins B, L and D in tumor tissues of mice infected with P-388 leukemia, as well as in liver and spleen and the activity of cathepsins B and L in serum were lower than their activity in mice infected with L1210/1 leukemia. Changes of cathepsin activity in liver and spleen of mice with leukemias have demonstrated a level of aggressiveness of tumor development and invasion of liver and spleen by neoplastic cells. The treatment resulted in the increase of cathepsin B, L and D activities in tumor tissue, liver, spleen and cathepsin B and L activities in serum. The highest activity of proteases was revealed in the groups of mice characterized by the greatest suppression of tumor growth. These data have shown that lysosomal proteases are involved in progression of murine experimental leukemias and elimination of tumor cells in the result of treatment. Determination of the activity of cysteine and aspartic proteases can be used for evaluation of cancer diseases malignancy, their sensitivity for chemotherapy and efficiency of treatment.

In this study, we have investigated the genotoxic, cytostatic, antineoplastic and apoptotic effects of three newly synthesized modified steroidal esters, having as alkylating agent p-N,N-bis(2-chloroethyl) aminophenyl butyrate (CHL) or p-N,N-bis(2-chloroethyl) aminophenyl acetate (PHE) esterified with the steroidal nucleus modified in the B- and D-ring. The genotoxic and cytotoxic effects of the compounds were investigated both in vitro, in lymphocyte cultures obtained from blood samples of healthy donors and in vivo, in ascites cells of P388 leukemia obtained from the peritoneal cavity of DBA/2 mice. Preparations were scored for sister-chromatid exchange (SCE) and proliferation-rate indices (PRI). The newly synthesized compounds were also studied for antineoplastic activity against lymphocytic P388 and lymphoid L1210 leukemias in mice, by calculating the mean of the median survival of the drug-treated animals (T) versus the untreated control (C) (T/C%). The activity of caspase-2 and caspase-3, indicators of apoptosis, was assessed biochemically in primary cultures of human lymphocytes. Our results show that the newly synthesized compounds caused severe genotoxic effects by significantly increasing the frequency of SCE and decreasing the PRI values in cultures of peripheral lymphocytes in vitro and in ascites cells of lymphocytic P388 leukemia in vivo. A significant correlation was also observed in both the in vitro and in vivo experiments: the higher the SCE frequency the lower the PRI value (r=-0.65, P<0.001 and r=-0.99, P<0.01, respectively). The measured antileukemic potency was statistically increased by all test compounds in both types of tumours, while the activity of caspase-2 and caspase-3 showed a statistically significant increase after two periods of exposure. The genotoxic (increase of SCE), cytostatic/cytotoxic (decrease of PRI) and antileukemic effects (increase of T/C%) in combination with the induction of apoptosis (activation of caspase-2 and caspase-3) caused by the newly synthesized compounds, lead us to propose them as agents with potentially antineoplastic properties.

Reliable surrogate markers of response to anticancer therapy remain a desirable tool for preclinical modelling and clinical practice in oncology. Clinical evaluation is relatively unreliable when attempting to assess rapidly and prospectively the outcome of treatment. Fluxes in released or circulating tumour marker levels are a useful but inconsistent marker of cytotoxic response. Serial measurement of circulating tumour cells appears to have some utility as a surrogate marker, but assay systems are expensive, and many cancers are not associated with the presence of circulating tumour cells. Because tissue breakdown is associated with release of nucleic acids and other cellular products, we reasoned that serial measurement of intra-tumoural pH may correlate with the extent of tumour lysis, and thus with outcomes of cytotoxic chemotherapy. Doxorubicin-sensitive and doxorubicin-resistant sublines of P388 murine monocytic leukaemia in C57BL/6 mice were treated with increasing concentrations of doxorubicin. Tumours were serially measured by conventional bi-dimensional methods and pH was sampled using a bevelled tip electrode. Mean and median pH changes were statistically different in responsive and resistant tumours, and amplitude of change correlated with long-term responses to doxorubicin. Serial sampling of pH in tumour masses may provide a useful surrogate of long-term response to chemotherapy.

Exogenous NO donor 3,3-bis-(nitroxymethyl)oxetane (NMO) was synthesized at the Institute for Problems of Chemical Physics (Russian Academy of Sciences). This compound was shown to inhibit cell death (apoptosis and necrosis) in cyclophosphamide-sensitive and cyclophosphamide-resistant P388 murine tumor. p53 protein was expressed in both lines of tumor cells. NO donor NMO had little effect on p53 protein expression in cells of both stains. Our results suggest that the proapoptotic effect of NMO is mediated by the p53-independent molecular mechanisms.

Heparin is known to attenuate tumor metastasis mainly by inhibiting the interaction between L-selectin and its ligand. However, the mechanism of heparin on lymphoma is unclear. This report demonstrates that both L-selectin/h IgG chimeric protein and heparin treatment can significantly inhibit the adhesion of P388D1 cells onto lymphatic sinusoids and marginal sinusoids in vitro, that heparin can attenuate P388D1 cell homing to lymph nodes in vivo at 12 hours, and that heparin significantly reduced P388D1 cells metastasis to lymph nodes 18 days after injection. These results indicate that heparin may act as a ligand for L-selectin on the P388D1 macrophage-like lymphoma cell line to attenuate tumor growth and metastasis.

The cytotoxicity of oxaziridines photogenerated after irradiation of chlordiazepoxide (CDZ) and its metabolites was investigated in vitro by a MTT assay on P388 leukemia and B16 melanoma cell lines and compared with that of the anticancer drug, melphalan. For the longer time-exposure experiment, oxaziridines had the same cytotoxicity as melphalan and this toxicity was higher when oxaziridines were photogenerated in the presence of cells. In conclusion, oxaziridines generated after CDZ, demoxepam, and desmethylchlordiazepoxide ultraviolet irradiation exhibited cytotoxicity activity against cancer cell lines. A possibility of CDZ use within the context of photodynamic therapy as a treatment for small, superficial tumors should not be excluded, because oxaziridines can be generated locally by skin-tumor local irradiation after CDZ topical administration.

Background: To investigate the antitumor effect of Inonotus obliquus Pilat, the antiproliferative effect of lanostane triterpenoids from a chloroform extract of I. obliquus sclerotia against mouse leukemia P388 cells was assessed., Materials and Methods: Cell viability was measured by MTT assay. Caspase-3/7 activity and DNA fragmentation were evaluated to analyze apoptosis induction. The in vivo antitumor effect was evaluated by the number of survival days of mouse leukemia P388-bearing female CDF1 mice., Results: The chloroform extract of I. obliquus sclerotia inhibited proliferation of the P388 cells. Among the triterpenoids examined, only inotodiol inhibited P388 cell proliferation. DNA fragmentation and caspase-3/7 activation were observed in the P388 cells treated with inotodiol (30 microM). A caspase-3 inhibitor, DEVD-CHO (N-acetyl-Asp-Glu-Val-Asp-al, 100 microM) partially inhibited the DNA fragmentation and growth-inhibition induced by inotodiol. The intraperitoneal administration of 10 mg/kg inotodiol prolonged the number of survival days of the P388-bearing mice., Conclusion: Inotodiol inhibits cell proliferation through apoptosis induction by activating caspase-3.

Exogenous NO donor 3,3-bis-(nitroxymethyl)oxetane (NMO) was synthesized at the Institute for Problems of Chemical Physics (Russian Academy of Sciences). This compound was shown to inhibit Ca2+-ATPase isolated from normal muscular cells and tumor cells. Both hydrolytic and transport functions of the enzyme were inhibited under these conditions. These changes were probably related to changes in membrane structure caused by NO donor. Our results suggest that changes in intracellular Ca2+ concentration can modulate the formation of tumor drug resistance.

Objective: To study the bioactive triterpene glycosides from sea cucumber Holothuria nobilis., Methods: Guided by Pyricularia oryzae bioassay method, the glycosides compounds were separated by multi-chromatography, and their structures were elucidated by chemical and spectral analysis., Results: Twelve triterpene glycosides were obtained and their structures were identified, including seven novel saponins. All saponins showed activities on P. oryzae, and most of them exhibited cytotoxicity on P388 and A549 significantly., Conclusion: Our researches provided valuable leads for pursuing new anticancer drugs, and established a homebase for further development of H. nobilis which is widely distributed in South China Sea.

Oxidative dimerization of ferulic acid methyl ester afforded dihydrobenzofuran derivative and new linear compound identified by X-ray crystallography. The gallate derivatized dihydrobenzofuran analogue was obtained and all compounds were evaluated for potential antiatherogenic, antiplasmodial (best IC(50)=0.8 microM) and cytotoxic activities.

Objective: To study the influence of a discrete nano-hydroxyapatite crystal (nano-HAp) on lymphatic leukemia P388 behavior by in vivo techniques., Methods: A nano-HAp was prepared by a neutralization reaction of 0.1 mol calcium hydroxide suspension and 0.06 mol phosphoric acid solutions at room temperature over pH7. The various doses of the nano-HAp only and the nano-HAp mixture with cyclophosphamide (CY) were injected into mice inoculated with solid tumor lymphatic leukemia P388 and dispersed into PRMI 1640 media harvested the leukemia P388 cells. Sixty P388 BALB/C mice were randomly grouped; 36 of them were used as nano-HAp treated groups and 24 mice as the control groups. The leukemia growth in the mice was examined morphologically, histopathologically and under a transmission electron microscope (TEM)., Results: The nano-HAp was identified as a hydroxyapatite by an X-ray diffractometry (XRD) and a Fourier transform infrared spectroscopy (FTIR). The morphology and sizes were observed under a TEM. The tissue growth inhibition ratio (weight%) of solid lymphatic leukemia P388 bearing mice treated with nano-HAp at doses 35 mg/kg, 53 mg/kg and nano-HAp (53 mg/kg) combined with CY (35 mg/kg) in 3 consecutive days via intraperitineal injections were 14.95%, 32.67% and 60.45% respectively. Apoptosis of P388 cell cocultured with nano-HAp was confirmed by TEM., Conclusions: The tissue growth restriction of solid tumor lymphatic leukemia P388 was greater after an injection of nano-HAp only or nano-HAp mixed with CY than that obtained after injection with physiological saline solution as a control (P < 0.01), and the tissue growth restriction of solid tumor after an injection of nano-HAp combined with CY was greater than that obtained after nano-HAp or CY injection only (P < 0.01).

Polymer nanoparticles are designed as nanovehicles to carry drugs in the body in a controlled manner increasing the concentration of the biologically active substance in the diseased organs and cells. The safety and biocompatibility of these nanosystems are those of the many properties that nanoparticles must meet to be used in vivo. Here we show that the cytotoxicity profile of poly(isobutylcyanoacrylate) (PIBCA) nanoparticles is affected by the way the nanosystems were produced and by the design of their surface. It was found that the tolerance of PIBCA nanoparticles by cells could be improved up to 100-fold by coating their surface with polysaccharides and haemoglobin.

This study has shown that murine monocytes/macrophages (Mo/Ma) can be labeled simply and efficiently with large, green-fluorescent, micrometer-sized particles of iron-oxide (MPIO). Neither size nor proliferation rate of the Mo/Ma is significantly affected by this labeling. The labeled Mo/Ma have been administered intravenously to rats that had developed a glioma following stereotactic injection of C6 cells. The labeled Mo/Ma were shown to target the brain tumors, a process that could be monitored non-invasively using T2*-weighted MRI. MRI observations were confirmed by Prussian blue staining, lectin staining and fluorescence histology. Overall, the results of this study suggest that the use of Mo/Ma may be envisaged in the clinic for vectorizing therapeutic agents towards gliomas.

Influence of a discrete nano-hydroxyapatite crystal (nano-HAp) on lymphatic leukemia P388 cell behavior was investigated by an in vitro technique using an MTT test and FITC analysis. The discrete nano-HAp was prepared by decanting upside clear layer of the nano-HAp suspension which was synthesized by a wet method using calcium hydroxide suspension and phosphoric acid solutions. The nano-HAp was identified as hydroxyapatite by the X-ray powder diffraction pattern and an infrared spectroscopy. The nano-HAp with concentrations of 8-40 microg/ml was dispersed into PRMI 1640 media with leukemia cells derived from BALB/C mice. The survival ratio of the cells decreased with the amounts of the nano-HAp increasing. Apoptosis rates of leukemia P388 cells on co-culturing with the nano-HAp of 35 microg/ml for 24, 48 h were 14.5% and 45.8%, respectively, and higher than those of 10.4% and 34% in controls. The G0/G1 peak values in leukemia P388 cell cycle were declined to reduce and the S peak values increased with extension time of co-culture. These results proved that the discrete nano-HAp can cause apoptosis of the leukemia P388 cells, and selectively act on G1 phase and arrest the G1 phase in cell cycle of the leukemia P388.

Various amphiphilic heterodinucleoside phosphates containing 1-beta-D-arabinofuranosylcytosine (ara-C) and 5- fluorodeoxyuridine (5-FdUrd) have recently been synthesized in order to increase the efficacy of ara-C and 5-FdUrd. Employing growth inhibition and growth recovery assays, we evaluated the in vitro effects of four of these dimers (No. 2, 2A, 3, 10) in L1210 and P388D1 murine leukemia cells. Although ara-C and 5-FdUrd appeared equimolar in all dimers, their contribution to the cytotoxicity of these agents was different. Thus, the liberation of ara-C and 5-FdUrd from their dimeric origin and their subsequent metabolic activation had a different course. In another set of experiments, we examined the in vivo effects of these agents in mice. The dimer with the highest cytotoxicity in vitro exerted the lowest acute toxicity and yielded the lowest therapeutic effect in vivo. The obtained data indicate that dimers with slower liberation of ara-C and 5-FdUrd were less cytotoxic, but prolonged liberation of both antimetabolites protected them from inactivation and extended the time period of therapeutic action. Some of the dimers exceeded the synergistic effects yielded by simultaneous application of both ara-C and 5-FdUrd. The significantly higher therapeutic potential of these new antitumor agents indicates that further studies are warranted.

The antitumor effects of the somatostatin structural derivative TT-232 in different rodent and xenograft tumor models are summarized in this report. TT-232 had previously been shown to inhibit the proliferation of a large number of cancer cell lines in vitro and reduce the size of different tumors in animal models in vivo. The effects of TT-232 by different routes of administration and treatment schedules were studied in various types of rodent and human xenograft tumor models. In the rodent tumor models S-180 sarcoma and P-388 lymphoid leukemia tumor the infusion treatment resulted in 76%-100% tumor growth inhibition and in 20%-60% of the mice being long-term and tumor-free survivors. In the aggressive C-26 colon carcinoma and MXT breast carcinoma, the TT-232 treatments resulted in 71%-75% tumor growth inhibition and an approximately 50% increased survival time. The tumor growth inhibitory effect of TT-232 on human tumor xenografts proved to be significant, resulting in 30%-80% decrease in tumor volume and in 20%-40% tumor-free animals. This antitumor efficacy of TT-232 was seen in almost all the tumors investigated. In our study, the route of infusion was shown to increase drug efficacy relative to conventional delivery methods. Our results suggested that TT-232 is an effective and promising antitumor agent.

Using four experimental model systems, it was demonstrated that glucomannan (GM) isolated from the cell wall of the industrial yeast Candida utilis revealed a broad range of protective activities. This effect depended on the nature and mode of action of the counteracting genotoxic compound as well as on the experimental model system used. In the Saccharomyces bioprotectivity assay, GM increased resistance towards ofloxacin-induced toxicity in the wild type and recombination repair-deficient yeast strains significantly enhancing survival of the cells. In the chromosomal aberration assay, GM exerted anticlastogenic effect against maleic hydrazide induced clastogenicity in Vicia faba L. In the DNA-topology assay, GM protected plasmid DNA from the breaks induced by Fe(2+) ions, but enhanced damage induced by bleomycin and hydrogen peroxide. In the cell-revitalization assay, it enhanced cytotoxic/cytostatic effect of teniposide applied to mouse leukemia cells. Thus, depending on the experimental model, GM acted as antimutagen, anticlastogen, DNA breaks inhibitor or inducer, and as cytotoxic/cytostatic effect enhancer. Several possible mechanisms of bioprotective action underlying the observed activities are suggested including iron chelation and free radical scavenging. The results imply that GM is a polysaccharide with marked biological activities and suggest its potential biomedical application, especially in combination with other bioactive compounds.

Fourteen compounds of 3,6-disubstituted-1,4-dihydro-1,2,4,5-tetrazine derivatives were prepared and their structures were confirmed by single-crystal X-ray diffraction and the semi-empirical calculation of PM3 method. This reaction yields the 1,4-dihydro derivatives rather than the 1,2-dihydro derivatives. The central six-membered ring of 1,4-dihydro-1,2,4,5-tetrazine has a chair conformation and therefore is not homoaromatic. Their antitumor activities were evaluated in vitro by SRB method for A-549 and BEL-7402 cells, and MTT method for P-388 and HL-60 cells. The results show that there is one compound which is highly effective against P-388 cells and one compound which is highly effective against HL-60 cells. So it is a kind of compound which possesses potential antitumor activities and is worth to research further.

Purpose: The activity of topotecan (TPT) against a number of hematological malignancies is now notably increased. TPT is a drug which inhibits the DNA enzyme topoisomerase I (topo I), thereby leading to the induction of tumor cell apoptosis. On the other hand, octreotide (OCT) is a synthetic analogue of somatostatin, which can induce apoptosis and antiproliferative effects on various human tumor cell lines, human xenografts and animal tumors, as well as on lymphoproliferative neoplasms. Hereby, we studied the effects of TPT and OCT, and their combination in the treatment of the rodent P388 lymphocytic leukemia, in vitro and in vivo., Materials and Methods: Cell cultures of P388 lymphocytic leukemia cells, as well as BDF1 male and female mice implanted with the P388 leukemia cells, were used for the in vitro and in vivo evaluation of the antineoplastic activity of OCT and TPT., Results: A significant increase of antileukemic activity of the combined treatment with both TPT and OCT was demonstrated. These results suggest that OCT enhances the effectiveness of TPT in the treatment of leukemia., Conclusion: Our results indicate that the combination of OCT with TPT in the treatment of hematological neoplasias is effective, and represents an interesting addition to the future therapeutic options, because os its mechanism of action and its toxicity profile.

Semi-synthetic routes to the enzyme inhibitory and potently anti-proliferative marine natural products discorhabdins P and U were developed by one-step methylation reactions of discorhabdins C and B, respectively. Two novel semi-synthetic derivatives of discorhabdin U were also prepared, one of which (6) exhibited significant anti-proliferative activity.

Lamellarin D is a marine alkaloid with a pronounced cytotoxicity against a large panel of cancer cell lines and is a potent inhibitor of topoisomerase I. However, lamellarin D maintains a marked cytotoxicity toward cell lines resistant to the reference topoisomerase I poison camptothecin. We therefore hypothesized that topoisomerase I is not the only cellular target for the drug. Using complementary cell-based assays, we provide evidence that lamellarin D acts on cancer cell mitochondria to induce apoptosis. Lamellarin D, unlike camptothecin, induces early disruption of the inner mitochondrial transmembrane potential (Deltapsi(m)) in the P388 leukemia cell line. The functional alterations are largely prevented by cyclosporin A, an inhibitor of the mitochondrial permeability transition (MPT), but not by the inhibitor of caspases, benzyloxycarbonyl-Val-Ala-Asp(Ome)-fluoromethylketone. Deltapsi(m) disruption is associated with mitochondrial swelling and cytochrome c leakage. Using a reliable real-time flow cytometric monitoring of Deltapsi(m) and swelling of mitochondria isolated from leukemia cells, we show that lamellarin D has a direct MPT-inducing effect. Furthermore, mitochondria are required in a cell-free system to mediate lamellarin D-induced nuclear apoptosis. The direct mitochondrial effect of lamellarin D accounts for the sensitivity of topoisomerase I-mutated P388CPT5 cells resistant to camptothecin. Interestingly, a tumor-active analogue of lamellarin D, designated PM031379, also exerts a direct proapoptotic action on mitochondria, with a more pronounced activity toward mitochondria of tumor cell lines compared with nontumor cell lines. Altogether, this work reinforces the pharmacologic interest of the lamellarins and defines lamellarin D as a lead in the search for treatments against chemoresistant cancer cells.

Reactive oxygen species generated by photosensitizers are efficacious remedy for tumor eradication. Eleven cycloimide derivatives of bacteriochlorin p (CIBCs) with different N-substituents at the fused imide ring and various substituents replacing the 3-acetyl group were evaluated as photosensitizers with special emphasis on structure-activity relationships. The studied CIBCs absorb light within a tissue transparency window (780-830 nm) and possess high photostability at prolonged light irradiation. The most active derivatives are 300-fold more phototoxic toward HeLa and A549 cells than the clinically used photosensitizer Photogem due to the substituents that improve intracellular accumulation (distribution ratio of 8-13) and provide efficient photoinduced singlet oxygen generation (quantum yields of 0.54-0.57). The substituents predefine selective CIBC targeting to lipid droplets, Golgi apparatus, and lysosomes or provide mixed lipid droplets and Golgi apparatus localization in cancer cells. Lipid droplets and Golgi apparatus are critically sensitive to photoinduced damage. The average lethal dose of CIBC-generated singlet oxygen per volume unit of cell was estimated to be 0.22 mM. Confocal fluorescence analysis of tissue sections of tumor-bearing mice revealed the features of tissue distribution of selected CIBCs and, in particular, their ability to accumulate in tumor nodules and surrounding connective tissues. Considering the short-range action of singlet oxygen, these properties of CIBCs are prerequisite to efficient antitumor photodynamic therapy.

Objective: To observe the pharmacodynamic and side effects of Wulong Kangai, a new drug of Chinese traditional herbal medicine, on 4 strains of mice transplantable tumors., Method: Mice transplantable tumors S180, H22, P388 and Lewis were used in the pharmacodynamic test on the granules of Wulong Kangai. The test on each tumor strain was repeated three times. In each test, 50 mice were used and divided into 5 groups. They were negative control group treated by physiological saline, cyclophosphamide control group and 3 test groups treated respectively with Wulong Kangai at deferent dosages of 10, 25, 40 g x kg(-1) x d(-1) in the treatment of Lewis and P388 and 15, 30, 50 g x kg(-1) x d(-1) in the treatment of S180 and H22., Result: The tumor weight were inhibited at the rates of 90.1%, 30.8%, 49.8% and 52. 3% in the mice with tumors of Lewis, P388, S180, and H22 by high dosage of Wulong Kangai as compared with negative control group. The inhibitory rates in cyclophosphamide groups were 90.6%, 77.2%, 79.6% and 60.3% respectively. The mice body weights grew slower in high dose groups treated by Wulong Kangai granule., Conclusion: Wulong Kangai was effective in treating mice transplantable tumors of Lewis, P388, S180 and H22 with a dose-dependent manner. The Lewis was the most sensitive strain to the drug among the 4 kinds of tested tumors. Side effects appeared during 9-11 days of uninterrupted treatment with high dose Wulong Kangai.

Two new dihydrochalcones, 2',4'-dihydroxy-3'-methoxydihydrochalcone, (-)-3'-methoxy-2',4',beta-trihydroxydihydrochalcone, a new flavanone, (2 S)-(-)-5'-hydroxy-7,3',4'-trimethoxyflavanone, and a new flavonol derivative, muntingone, along with sixteen known compounds, were isolated from the leaves of Muntingia calabura. The structures of these new compounds were determined using spectral analyses including extensive 2D NMR data. Among the isolates, (2 S)-5'-hydroxy-7,3',4'-trimethoxyflavanone, 4'-hydroxy-7-methoxyflavanone, 2',4'-dihydroxychalcone, and 2',4'-dihydroxy-3'-methoxychalcone exhibited cytotoxicity (IC (50) values < 4 microg/mL) against P-388 and/or HT-29 cell lines in vitro.