Combination of selol nanocapsules and magnetic hyperthermia hinders breast tumor growth in aged mice after a short-time treatment

Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with magnetic hyperthermia (MHT) is evaluated in aged Erhlich tumor-bearing mice. Clinical, hematological, biochemical, genotoxic and histopathological parameters are assessed during 7 d treatment with NcSel and MHT, separately or combined. The time evolution of the tumor volume is successfully modeled using the logistic mathematical model. The combined therapy comprising NcSel and MHT is able to hinder primary tumor growth and a case of complete tumor remission is recorded. Moreover, no metastasis was diagnosed and the adverse effects are negligible. NcSel plus MHT may represent an effective and safe alternative to cancer control in aged patients. Future clinical trials are encouraged.

Graphene Oxide Theranostic Effect: Conjugation of Photothermal and Photodynamic Therapies Based on an in vivo Demonstration

INTRODUCTION

Cancer is the second leading cause of death globally and is responsible, where about 1 in 6 deaths in the world. Therefore, there is a need to develop effective antitumor agents that are targeted only to the specific site of the tumor to improve the efficiency of cancer diagnosis and treatment and, consequently, limit the unwanted systemic side effects currently obtained by the use of chemotherapeutic agents. In this context, due to its unique physical and chemical properties of graphene oxide (GO), it has attracted interest in biomedicine for cancer therapy.

METHODS

In this study, we report the in vivo application of nanocomposites based on Graphene Oxide (nc-GO) with surface modified with PEG-folic acid, Rhodamine B and Indocyanine Green. In addition to displaying red fluorescence spectra Rhodamine B as the fluorescent label), in vivo experiments were performed using nc-GO to apply Photodynamic Therapy (PDT) and Photothermal Therapy (PTT) in the treatment of Ehrlich tumors in mice using NIR light (808 nm 1.8 W/cm2).

RESULTS

This study based on fluorescence images was performed in the tumor in order to obtain the highest concentration of nc-GO in the tumor as a function of time (time after intraperitoneal injection). The time obtained was used for the efficient treatment of the tumor by PDT/PTT.

DISCUSSION

The current study shows an example of successful using nc-GO nanocomposites as a theranostic nanomedicine to perform simultaneously in vivo fluorescence diagnostic as well as combined PDT-PTT effects for cancer treatments.

The effect of peritoneal dialysis with alkaline dialysate in peritonitis carcinomatosis: an experimental study in mice

OBJECTIVE

The aim of this study was to neutralize acidic pH using an alkaline dialysate for continuous ambulatory peritoneal dialysis (CAPD) in mice with peritoneal carcinomatosis (PC) and to investigate the change of the pH level in the acidic fluid along with its effects on liver oxidative stress, liver and kidney histopathology and the lifespan of the body.

MATERIALS AND METHODS

A total of 38 mice were randomly divided into 4 groups.PC development was inhibited by intraperitoneal injection of Ehrlich tumor cells in all mice in each group.

RESULTS

In the group-1 receiving CAPD, the pH levels of acidic liquid were higher; and the levels of liver TBARS were lower with higher reduced glutathione levels. Histopathological damage in group-1 was less than in group-2. In Group 3 receiving CAPD, the average lifespan extended by 10.4%. The average lifespan extended by 26.1%.

CONCLUSION

This study indicated that applying CAPD with alkaline dialysate in PC contributed to the neutralization of acidosis of the intraperitoneal acid structure;had favorable effects on oxidative stress markers in liver tissue; prevented histopathological injury in liver and kidney tissues, and extended the life span of the body in mice. As this is a simple, inexpensive, and easily available method, larger studies are warranted to evaluate its effects.

Hyperthermic Potentiation of Cisplatin Cytotoxicity on Solid Ehrlich Carcinoma

Background

Hyperthermia produces marked effects on many biochemical parameters of tumor cells and has been reported to potentiate the effect of many drugs. We therefore evaluated the possible synergistic effect between hyperthermia and cisplatin against solid Ehrlich carcinoma. The study was based on the measurement of some biologic characteristics in tumor tissues, namely: DNA, RNA, and protein content and their rate of synthesis as parameters for nuclear damage; total lipids and cholesterol as parameters for membrane damage; acid-phosphatase and acid-ribonuclease as parameters for lysosomal damage; and tumor volume as a direct parameter for tumor growth.

Methods

Treatment of solid Ehrlich carcinoma by hyperthermia at 43 °C for 30 min for 3 successive days produced a 41.5 % decrease in tumor volume, as well as a significant decrease in nucleic acids, protein contents and their rate of synthesis, in total lipids and cholesterol, and in acid-phosphatase and acid-ribonuclease. Chemotherapeutic management of the tumor by 5 mg/kg × 3 of cisplatin alone showed a continuous increase in tumor volume but at a lower rate than that of the untreated control. However, when cisplatin was given 1 h prior to hyperthermia, the tumor volume was significantly decreased by 82.6 %.

Results

The effects observed on all the investigated parameters were intensified when cisplatin was combined with hyperthermia. The results obtained suggest that hyperthermia may enhance the penetration of cisplatin to its target site inside the tumor cells due to a membrane-damaging effect. The enhanced lethality of cisplatin on tumor cells may also be due to the inhibition of DNA repair processes by hyperthermia.

[Reprogrammed M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 extends lifespan of mice with experimental carcinoma]

Objective. Reprogramming of M1 macrophage phenotype with inhibited M2 phenotype transcription factors, such as STAT3, STAT6 and SMAD and assess their impact on the development of Ehrlich carcinoma (EC) in vitro and in vivo. Methods. Tumor growth in vitro was initiated by addition of EC cells in RPMI-1640 culture medium and in vivo by intraperitoneal of EC cell injection into mice. Results. It was found that M1-STAT3/6- SMAD3 macrophages have a pronounced anti-tumor effect in vitro, and in vivo, which was greater than anti-tumor effects of M1, M1-STAT 3/6, M1-SMAD3 macrophages and cisplatin. Conclusion. M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 effectively restrict tumor growth. The findings justify the development of new anti-tumor cell therapy technology.

Improved Targeting of Photosensitizers by Intratumoral Administration of Immunoconjugates

Biodistribution of technetium (99m Tc) labeled hematoporphyrin derivative (HpD, Photosan-3) conjugated to a monoclonal antibody to carcinoembryonic antigen (anti-CEA) was compared following intravenous ( i.v.) and intratumoral ( i.t.) administration in solid Ehrlich ascites tumor bearing mice. Images of mice at different time intervals were acquired after injection of radiolabeled PS-3 in either conjugated or unconjugated forms. Quantitative estimation of the radiolabel in different tissues was performed by selecting the different region of interests (ROIs). Maximum accumulation of both free and antibody conjugated PS-3 following i.v. administration was observed in liver followed by tumor. Tumor/muscle (T/N) ratio was more with free PS-3 compared to conjugated PS-3. Pharmacokinetics of free and conjugated PS-3 was also different with faster accumulation of conjugated PS-3 in the tumor. With intratumoral administration of anti-CEA-PS-3-99m Tc, specific accumulation and retention of the sensitizer was observed in the tumor tissue. Since, direct injection of antibody conjugated photosensitizer into the tumor resulted in longer retention of the dye in the tumor with no accumulation in the normal tissues, the present results imply that the toxicity to normal tissues could be reduced significantly with selective destruction of the tumor following photodynamic treatment with the use of i.t. administration of specific antibodies conjugated to photosensitizers.

Features of the Antitumor Effect of Vaccinia Virus Lister Strain

Oncolytic abilities of vaccinia virus (VACV) served as a basis for the development of various recombinants for treating cancer; however, "natural" oncolytic properties of the virus are not examined in detail. Our study was conducted to know how the genetically unmodified L-IVP strain of VACV produces its antitumor effect. Human A431 carcinoma xenografts in nude mice and murine Ehrlich carcinoma in C57Bl mice were used as targets for VACV, which was injected intratumorally. A set of virological methods, immunohistochemistry, light and electron microscopy was used in the study. We found that in mice bearing A431 carcinoma, the L-IVP strain was observed in visceral organs within two weeks, but rapidly disappeared from the blood. The L-IVP strain caused decrease of sizes in both tumors, however, in different ways. Direct cell destruction by replicating virus plays a main role in regression of A431 carcinoma xenografts, while in Ehrlich carcinoma, which poorly supported VACV replication, the virus induced decrease of mitoses by pushing tumor cells into S-phase of cell cycle. Our study showed that genetically unmodified VACV possesses at least two mechanisms of antitumor effect: direct destruction of tumor cells and suppression of mitoses in tumor cells.

Synergic carcinostatic effects of ascorbic acid and hyperthermia on Ehrlich ascites tumor cell

AIM

In this study, we evaluated the carcinostatic effects of combined ascorbic acid (AsA) and a capacitive-resistive electric transfer (CRet) hyperthermic apparatus-induced hyperthermic treatment on Ehrlich ascites tumor (EAT) cells.

MATERIALS AND METHODS

EAT cells were exposed to various AsA (0-10 mM) concentrations for 1 h; they subsequently underwent CRet treatment for 15 min at 42 °C. Cell viability was assessed by the WST-8 assay 24 h after the combined treatment. Reactive oxygen species involvement was evaluated using catalase and tempol; caspase-3/7 activation was determined by their fluorescent substrates; cell proliferation were estimated by time-lapse observation. The effect on the cell cycle was analyzed by flow cytometry.

RESULTS

Combined AsA and CRet treatment synergistically suppressed cell viability compared with either treatment alone, and these synergistically carcinostatic effects were evident even at noncytotoxic concentrations of AsA alone (≤ 2 mM). The carcinostatic effects of combined AsA and CRet treatment were attenuated in a dose-dependent manner by catalase addition, but not by the superoxide anion radical scavenger tempol. Time-lapse observation revealed that combined AsA and CRet treatment activated caspase-3/7 at 10-24 h after treatment, accompanied by significant cell growth suppression. Cell cycle analysis revealed that the rate of sub-G1-phase (apoptotic) cells was drastically increased at 12 h and 24 h, and that the G2/M-phase cells gradually increased at 6-24 h after treatment.

CONCLUSION

These results indicate that combined AsA and CRet treatment synergistically inhibits EAT cell growth through G2/M arrest and apoptosis induction via H2O2 generation at lower AsA concentrations; this carcinostatic effect cannot be exerted by AsA alone.

[Bacterial phagelysates and malignant tumor growth]

Anti-tumor preventive efficacy of E.coli phagelysate has been studied. Investigations were conducted on 2-3 months 48 male mice. Regimen of preventive vaccinations were: single - 0,25 ml phagelysate intraperitoneal injection, 3 days before Ehrlich carcinoma inoculation (1x10(6) tumor cells); 3 times vaccinations (0,25 ml, with 3 day intervals) 3, 6, and 9 days before inoculation of carcinoma; and 10 times (during 10 days, before inoculation of carcinoma). Treatment efficacy was evaluated according to the indices of cancer growth (development of cancer tissue, cancer growth inhibition percent, lifespan and survival percent). Experiments have shown that single and 3 times preventive vaccinations inhibited tumor development and delayed malignant growth, while, 10 times permanent vaccinations had no effects on cancer growth. Cancer growth inhibition percent in single and 3 times vaccinated animals were 58% on the average. Maximal lifespan in control group mice consisted 59 days. By the 125th day of cancer growth, at single vaccination 17% of mice were alive, while in 3 times vaccinated mice the survival percent was 25%. Anti-tumor potential of E.coli pagelysate supposedly could be explained by immunoregulatory properties of the preparation.

Tissue distribution and efficacy of gold nanorods coupled with laser induced photoplasmonic therapy in ehrlich carcinoma solid tumor model

Gold nanorods (GNR) within tumor microregions are characterized by their ability to absorb near IR light and emit heat in what is called photoplasmonic effect. Yet, the efficacy of nanoparticles is limited due to intratumoral tissue distribution reasons. In addition, distribution of GNRs to normal tissue might result in non specific toxicity. In the current study, we are assessing the intratumoral and tissue distribution of PEGylated GNRs on the top of its antitumor characteristics when given intravenously or intratumoral to solid tumor bearing mice and coupled with laser photoplasmonic sessions. PEGylated GNRs with a longitudinal size of less than 100 nm were prepared with aspect ratio of 4.6 showing strong surface plasmon absorption at wavelength 800 nm. Pharmacokinetics of GNR after single I.V. administration (0.1 mg/kg) showed very short systemic circulating time (less than 3 h). On the other hand, tissue distribution of I.V. GNR (0.1 mg/kg) to normal animals showed preferential deposition in spleen tissue. Repeated administration of I.V. GNR resulted in preferential accumulation in both liver and spleen tissues. In addition, I.V. administration of GNR to Ehrlich carcinoma tumor bearing mice resulted in similar tissue distribution; tumor accumulation and anti-tumor effect compared to intratumoral administration. In conclusion, the concentration of GNR achieved within tumors microregions after I.V. administration was comparable to I.T. administration and sufficient to elicit tumoral growth arrest when coupled with laser-aided photoplasmonic treatment.

Effects of specific antibodies and immunocompetent cells on tumor growth in passive transfer experiment

Experiments with passive transfer of immunocompetent cell and serum demonstrated suppression of tumor growth after transfer of splenocytes from animals immunized with Trypanosoma cruzi. The nonspecific constituent of antitumor effect of immunocompetent cells was detected. The previously reported oncoprotective effect of mucins 2 and 3 was not confirmed.

Antitumor and adjuvant effects of phagelysates of E.coli in mice with Ehrlich carcinoma

AIM

To augment anti-tumor host response and overcome the tumor-induced immunosuppression is of paramount importance especially when patient is subjected to radio-/chemotherapy and immune system suffers significantly. Various immunological methods have been employed as supplemental antitumor therapies. We were aimed to investigate the antitumor potential of phagelysates of gram-negative bacteria and their adjuvant effects for conventional chemotherapy in experiment.

METHODS

Bacterial phagelysates of E.coli and purified suspensions of corresponding Un bacteriophage were obtained by standard methods of phage research. Experiments were carried out on BL57C/6J mice bearing transplanted Ehrlich carcinoma. Different regimens of phagelysate administration (0,5 ml E. coli phagelysate, 3/8 times with 5 day intervals) and conventional chemotherapy (combination of Doxorubicin 60 mg/m2, Cyclophosphan 800 mg/m(2), Ftoruracil 600 mg/m(2), 3 times with 21 day intervals) were tested. Treatment efficacy was evaluated by tumor growth inhibition percent, index of malignant growth, lifespan and survival percent.

RESULTS

Experiments have shown that application of optimal doses of E. coli phagelysate can be well tolerated in mice. No stimulation or support of malignant growth was observed. E. coli phagelysate exhibited significant anticancer effect and adjuvant efficacy. Cancer development was delayed in 65% of inoculated animals in the test group. E. coli phagelysate inhibited tumor growth by 80-90% without apparent side effects. The mice survival was prolonged twice and more. On 65th-69th days of tumor growth in 13% animals complete regression of neoplasms was registered. Application of phagelysates in combination with chemotherapy significantly increased antitumor efficacy of conventional chemotherapeutic drugs.

CONCLUSION

Application of bacterial phagelysates can be considered as promising novel strategy in cancer therapeutics.

Plasmonic nanopowders for photothermal therapy of tumors

We describe a novel strategy for the fabrication of plasmonic nanopowders (dried gold nanoparticles) by using wet chemical nanoparticle synthesis, PEG-SH functionalization, and a standard freeze-drying technique. Our strategy is illustrated by successful fabrication of different plasmonic nanopowders, including gold nanorods, gold-silver nanocages, and gold nanospheres. Importantly, the dried nanoparticles can be stored for a long time under usual conditions and then can easily be dissolved in water at a desired concentration without such hard manipulations as sonication or heating. Redispersed samples maintain the plasmonic properties of parent colloids and do not form aggregates. These properties make pegylated freeze-dried gold nanoparticles attractive candidates for plasmonic photothermal therapy in clinical settings. In this work, redispersed gold nanorods were intravenously administered to mice bearing Ehrlich carcinoma tumors at doses of 2 and 8 mg (Au)/kg (animal). Particle biodistribution was measured by atomic absorption spectroscopy, and tumor hyperthermia effects were studied under laser NIR irradiation. Significant tumor damage was observed only at the higher dose of the nanorods.

[Application of bacterial thermo- and phagelysates for suppression of malignant tumor growth in experimental studies: 2 comparative analysis of anticancer efficacy of thermo- and phagelysates of Ps. aeruginosa and E. coli]

In the presented work antitumor effects of thermo- and phagelysates of Ps.aeruginosa and E.coli on Ehrlich carcinoma growth in mice have been studied. The treatment efficacy was evaluated according to the dynamic changes in volume of cancer tissue, cancer growth inhibition percent and calculations using Semi-empirical mathematical model describing cancer volume variations in relation to time passed after carcinoma inoculation. It was shown that at the early stage of cancer growth all tested bacterial preparations significantly inhibit cancer growth. Antitumor treatment effects were better expressed in animal studies using bacterial pagelysates in comparison to that of thermolysates. Comparative analysis of anticancer treatment efficacy of Ps.aeruginosa and E.coli phagelysates have shown that E.coli phagelysates reveal stronger and more prolonged anticancer treatment properties than phagelysates of Ps.aeruginosa.

[Application of bacterial thermo-and phagelysates for suppression of malignant tumor growth in experimental studies: 1. Anticancer efficacy of thermo- and phagelysates of E.coli]

Immunotherapy is considered as one of the promising treatment strategies for patients with malignant tumors. In the presented work antitumor effects of E.coli thermo- and phagelysates on Ehrlich carcinoma growth in mice have been studied. The treatment efficacy was evaluated by estimation of dynamic changes in volume of cancer tissue and by the percentage of cancer growth inhibition. Semi-empirical mathematical model, describing cancer volume variations in relation to time, passed after Ehrlich carcinoma inoculation was elaborated. It was shown that at the early stage of cancer growth both tested bacterial preparations significantly inhibit cancer growth. Antitumor treatment effects were better expressed in animal studies using bacterial phagelysates in comparison to that of thermolysates. After cessation of administration of bacterial preparations a prolonged antitumor activity in animals treated with E. coli phagelysates was demonstrated.

Inhibition of subcutaneous growth of Ehrlich ascites carcinoma (EAC) tumor by post-immunization with EAC-cell gangliosides and its anti-idiotype antibody in relation to tumor angiogenesis, apoptosis, cell cycle and infiltration of CD4+, CD8+ lymphocytes, NK cells, suppressor cells and APC-cells in tumor

Both EAC-tumor associated gangliosides and its anti-idiotype antibody inhibited growth of this tumor significantly. Immuno-histological studies with von Willebrand Factor (vWF) antibody indicated that tumor angiogenesis as determined by expression of vWF decreased in tumors of mice, post-immunized with EAC-cell gangliosides as well as its anti-idiotype antibody. Infiltration of various immune cells of the host in the tumor correlated to some extent with tumor-growth inhibition. Apoptosis study using AnnexinV-FITC and propidium iodide indicated that tumor growth inhibition in mice post-immunized with EAC-gangliosides and its anti-idiotype antibody were due to enhanced apoptosis and cell death. Cell cycle analysis by FACS indicated that EAC-cell associated gangliosides and its anti-idiotype antibody were acting both at the M2 i.e. S and M3 i.e. G2/M phases of the cell cycle to arrest tumor growth.

Hyperthermic effect of multi-walled carbon nanotubes stimulated with near infrared irradiation for anticancer therapy: in vitro studies

It is proposed to use the novel paradigm of treating cancer with hyperthermic therapy using multi-walled carbon nanotubes (MWCNT) stimulated with near infrared (NIR) irradiation.

AIM

To establish the capacity of MWCNT stimulated with NIR irradiation to destroy Erlich ascitic carcinoma (EAC) cells.

MATERIALS AND METHODS

EAC cells suspension was irradiated with NIR heating lamp with a wavelength of 0.78-1.40 mm and power density of 3.5 W/cm2 over 1.5 min in the presence of MWCNT (0.1 mg/ml). The changes in the temperature of suspension with the NIR exposure time was measured using the differential cooper-constantan thermocouple. The viability of EAC cells was evaluated by trypan blue staining.

RESULTS

The death of 95.2% of EAC cells in the presence of MWCNT was observed after 1.5 min of NIR light irradiation: thermal ablation temperature was approximately 50 degrees C.

CONCLUSIONS

It was demonstrated that addition of MWCNT to EAC cell suspension results in the photo-ablative destruction of cells exposed to short time NIR irradiation.

[Effect of weak combined static and low-frequency alternating magnetic fields on the Ehrlich ascites carcinoma in mice]

The parameters of the low-frequency (1, 4.4, 16.5 Hz or the sum of these frequencies) extremely weak (300, 100, 150-300 nT, according to frequencies) alternating component of combined magnetic fields have been found, which in combination with a weak collinear static constant field of 42 nT (the induction corresponds to the range of the geomagnetic field) has a marked antitumor activity. The exposure to these magnetic fields inhibits the tumor growth in mice with the intraperitoneally transplanted Ehrlich ascites carcinoma. The effect manifests itself in an increase in the life of tumor-bearing animals and in the content of damaged tumor cells. It was found that the death of tumor cells by the action of weak fields occurs predominantly by the mechanism of necrosis.

Damage effects of protoporphyrin IX - sonodynamic therapy on the cytoskeletal F-actin of Ehrlich ascites carcinoma cells

In this study, we report evidence of the damage effects of sonodynamic therapy (SDT) on a novel intracellular target, cytoskeletal F-actin, that has great importance for cancer treatment. Ehrlich ascites carcinoma (EAC) cells suspended in PBS were exposed to ultrasound at 1.34 MHz for up to 60s in the presence and absence of protoporphyrin IX (PPIX). To evaluate the polymeric state and distribution of actin filaments (AF) we employed FITC-Phalloidin staining. The percentage of cells with intact AF was decreased with 10-80 microM PPIX after ultrasonic exposure, while only few cells with disturbed F-actin were observed with 80 microM PPIX alone. The fluorescence intensity of FITC-Phalloidin labeled cells was detected by flow cytometry. The morphological changes of EAC cells were observed by scanning electron microscope (SEM). The nuclei were stained with Hoechst 33258 to determine apoptosis. Cytoskeletal F-actin and cell morphological changes were dependent on the time after SDT. Some cells suffered deformations of plasma membrane as blebs that reacted positively to FITC-Phalloidin at 2h after SDT treatment. Many of the cells showed the typically apoptotic chromatin fragmentation. The alterations were more significant 4h later. Our results showed that cytoskeletal F-actin might represent an important target for the SDT treatment and the observed effect on F-actin and the subsequent bleb formation mainly due to apoptosis formation due to the treatment.

Promotive effects of hyperthermia on the cytostatic activity to Ehrlich ascites tumor cells by diverse delta-alkyllactones

AIM

To evaluate promotive effects of hyperthermia on antitumor activity of new delta-alkyllactones (DALs) of low molecular weight (184-254 Da), chemically synthesized, which are different from natural macrocyclic lactones of high molecular weight (348-439 Da), such as camptothecin and sultriecin.

METHODS

A suspension of Ehrlich ascites tumor (EAT) cells was mixed with a DAL in a glass tube, heated at 37 or 42 degrees C for 30 min in a water bath, and cultured at 37 degrees C for 20 or 72 h. Cell viability was measured by the mitochondrial dehydrogenase- based WST-1 assay. DALs incorporated into EAT cells was extracted and measured by gas-liquid chromatography.

RESULTS

The reduction of cell viability by DALs was markedly enhanced upon the treatment at 42 degrees C compared to that at 37 degrees C. At 37 degrees C, delta-hexadecalactone (DH16:0) and delta-tetradecalactone (DTe14:0) displayed cytostatic activity (at 100 microM survival level: 20.7%, 66.1%; at 50 microM--41.2%, 82.4%, respectively). Their activity was more marked at 42 degrees C (at 100 microM 10.6%, 27.6%; at 50 microM 30.6, 37.5%, ibid). The other DALs, delta-undecalactone (DU11:0), delta-dodecalactone (DD12:0), and delta-tridecanolactone (DTr13:0) were almost ineffective. Evaluation of survival rate in the cells treated for 30 min by DALs with the next culturing of EAT cells for 72 h resulted in the enhanced carcinostatic activity of DH16:0 and DTe14:0 even at concentrations as low as 25 microM at either 37 degrees C (18.5%, 78.5%, ibid) or 42 degrees C (5.0%, 42.0%, ibid), but the others exhibited slight activity or none. DH16:0 was effective at either 37 degrees C (36.0%) or 42 degrees C (23.0%) even at a lower dose of 10 microM. At the same time only the most cytostatic DH16:0 was incorporated into EAT cells and the rate of incorporation was more at 42 degrees C than at 37 degrees C.

CONCLUSION

Delta-hexadecanolactone (DH16:0) exhibited the most cytostatic effect that was significantly enhanced by hyperthermia. It allows to consider it as a potent antitumor agent, especially in combination with hyperthermia.

Saccharomyces cerevisiae, the Baker's Yeast, suppresses the growth of Ehrlich carcinoma-bearing mice

This study was undertaken to evaluate the effectiveness and mechanisms of anti-tumor activity of Baker's yeast, Saccharomyces cerevisiae, in immunocompetent mice. Swiss albino mice were inoculated intramuscularly in the right thigh with Ehrlich Ascites Carcinoma (EAC) cells. At day 8, mice bearing Solid Ehrlich Carcinoma tumor (SEC) were intratumorally (IT) injected with killed S. cerevisiae (10 x 10(6) and 20 x 10(6) cells) for 35 days. Histopathology of yeast-treated mice showed extensive tumor degeneration, apoptosis, and ischemic (coagulative) and liquefactive necrosis. These changes are associated with a tumor growth curve that demonstrates a significant antitumor response that peaked at 35 days. Yeast treatment (20 x 10(6) cells) three times a week resulted in a significant decrease in tumor volume (TV) (67.1%, P < 0.01) as compared to PBS-treated mice. The effect was determined to be dependent on dose and frequency. Yeast administered three and two times per week induced significant decrease in TV as early as 9 and 25 days post-treatment, respectively. Administration of yeast significantly enhanced the recruitment of leukocytes, including macrophages, into the tumors and triggered apoptosis in SEC cells as determined by flow cytometry (78.6%, P < 0.01) at 20 x 10(6) cells, as compared to PBS-treated mice (42.6%). In addition, yeast treatment elevated TNF-alpha and IFN-gamma plasma levels and lowered the elevated IL-10 levels. No adverse side effects from the yeast treatment were observed, including feeding/drinking cycle and life activity patterns. Indeed, yeast-treated mice showed significant final body weight gain (+21.5%, P < 0.01) at day 35. These data may have clinical implications for the treatment of solid cancer with yeast, which is known to be safe for human consumption.

Application of DNA from mushroom Pleurotus ostreatus for cancer biotherapy: a pilot study

AIM

In present work, the attempt to study immunomodulatory activity and biotherapeutical potential of DNA isolated from the fruit body of P. ostreatus was made.

METHODS

The efficacy of biotherapeutic application of mushroom DNA was evaluated on the BALB/c mice with subcutaneously transplanted Ehrlich carcinoma. The effect of Pleurotus ostreatus DNA on NK activity was studied in vitro using nonspecific cytotoxicity assay.

RESULTS

Application of mushroom DNA resulted in augmentation of NK cytotoxic activity in vitro and significant increase of the life span of mice with solid Ehrlich carcinoma.

CONCLUSION

The observed effects of P. ostreatus DNA administration can be probably explained by the presence of immunostimulatory unmethylated CpG motifs in DNA.

[Investigation of antitumor action of acoustic resonance induced by theta-rhythm modulation]

Acoustic resonance induced by theta-rhythm modulation of bioelectric activity caused moderate inhibition of solid Ehrlich tumors to take place and extended murine life span. No untoward side-effects were registered.

Antitumor effectiveness of different amounts of electrical charge in Ehrlich and fibrosarcoma Sa-37 tumors

Background

In vivo studies were conducted to quantify the effectiveness of low-level direct electric current for different amounts of electrical charge and the survival rate in fibrosarcoma Sa-37 and Ehrlich tumors, also the effect of direct electric in Ehrlich tumor was evaluate through the measurements of tumor volume and the peritumoral and tumoral findings.

Methods

BALB/c male mice, 7–8 week old and 20–22 g weight were used. Ehrlich and fibrosarcoma Sa-37 cell lines, growing in BALB/c mice. Solid and subcutaneous Ehrlich and fibrosarcoma Sa-37 tumors, located dorsolaterally in animals, were initiated by the inoculation of 5 × 10⁶ and 1 × 10⁵ viable tumor cells, respectively. For each type of tumor four groups (one control group and three treated groups) consisting of 10 mice randomly divided were formed. When the tumors reached approximately 0.5 cm³, four platinum electrodes were inserted into their bases. The electric charge delivered to the tumors was varied in the range of 5.5 to 110 C/cm³ for a constant time of 45 minutes. An additional experiment was performed in BALB/c male mice bearing Ehrlich tumor to examine from a histolological point of view the effects of direct electric current. A control group and a treated group with 77 C/cm³ (27.0 C in 0.35 cm³) and 10 mA for 45 min were formed. In this experiment when the tumor volumes reached 0.35 cm³, two anodes and two cathodes were inserted into the base perpendicular to the tumor long axis.

Results

Significant tumor growth delay and survival rate were achieved after electrotherapy and both were dependent on direct electric current intensity, being more marked in fibrosarcoma Sa-37 tumor. Complete regressions for fibrosarcoma Sa-37 and Ehrlich tumors were observed for electrical charges of 80 and 92 C/cm³, respectively.

Histopathological and peritumoral findings in Ehrlich tumor revealed in the treated group marked tumor necrosis, vascular congestion, peritumoral neutrophil infiltration, an acute inflammatory response, and a moderate peritumoral monocyte infiltration. The morphologic pattern of necrotic cell mass after direct electric current treatment is the coagulative necrosis. These findings were not observed in any of the untreated tumors.

Conclusion

The data presented indicate that electrotherapy with low-level DEC is feasible and effective in the treatment of the Ehrlich and fibrosarcoma Sa-37 tumors. Our results demonstrate that the sensitivity of these tumors to direct electric current and survival rates of the mice depended on both the amount of electrical charge and the type of tumor. Also the complete regression of each type of tumor is obtained for a threshold amount of electrical charge.

Influence of temperature on the efficiency of photodestruction of Ehrlich ascites carcinoma cells sensitized by hematoporphyrin derivative

AIM

To elucidate the mechanism of the potentiating influence of heating associated with photoirradiation on the antitumor efficiency of photodynamic therapy (PDT) with hematoporphyrin derivative (HPD).

METHODS

The study was carried out on Ehrlich ascites carcinoma (EAC) cells, which were loaded with HPD in a serum-free medium and then irradiated with red light (lambda max=630 nm) at various temperatures. Cytotoxicity was estimated by the trypan blue exclusion assay.

RESULTS

Our data support the view that in PDT the hyperthermia (around 44 degrees C) produced by irradiation can enhance synergistically the HPD-photoinduced tumor eradication; it was found that raising the irradiation temperature from 30 to 44 degrees C caused a substantial (approximately 1.5 fold) increase in the rate of HPD-photosensitized inactivation of EAC cells, while hyperthermia (44 degrees C) itself showed little toxic effects towards the cells.

CONCLUSION

Studies indicated that the potentiating effect of heating on the antitumor efficiency of HPD-PDT could be largely explained by the stimulation of reactive oxygen species formation such as H2O2, superoxide and hydroxyl radicals. It was also found that photosensitization of EAC cells by HPD caused a strong fall in the activity of catalase (CAT) and glutathione (GSH) peroxidase, and that heating sensitized the H2O2-detoxifying enzymes to HPD-photoinduced inactivation. Under HPD-PDT, these events could result in loss of protection against accumulating H2O2; we revealed that cell-bound CAT and the GSH redox cycle play an important role in the protection of EAC cells against HPD-PDT. Moreover, our findings suggest that during PDT with HPD, an increase in the temperature of tumors could enhance the efficiency of this therapy via the stimulation of a chlorin-type photoproduct formation.

Enhancement of antitumor effects of 5-fluorouracil combined with ultrasound on Ehrlich ascites tumor in vivo

To evaluate the role of ultrasonic waves in enhancing the effect of 5-fluorouracil (5-FU) as anticancer drug, tumor growth, cell ultrastructure and temperature rises of ascites Ehrlich tumor implanted in mice were investigated at a frequency of 0.8 MHz. Different conditions of ultrasonic intensity (1, 2 and 3 W/cm(2)), sonocation time (1, 3 and 5 min) and waveform (continuous and pulsed) were studied. A total of 10 mg/kg body weight of 5-FU was IV injected into the mice bearing Ehrlich tumors on days of 1, 3, 5, 8, 10 and 12 of therapy. After 24 h of each injection with 5-FU, tumor sites were sonocated at room temperature of 22 degrees C. Tumor volumes were monitored by using ultrasonic imaging system during treatment just before each 5-FU injection, and on the 15th day of treatment. Density and ultrasonic attenuation of excised tumor tissues were measured in vitro and used to estimate the temperature rises due to ultrasonic absorption. Density and attenuation coefficients of excised tumor tissues were found to be dependent on the treatment regimen. The estimated rate of temperature rise and equilibrium temperature, and the characteristic time to reach equilibrium are given for each group. Results obtained indicate that tumor growth decreases with increasing of ultrasonic intensity and sonocation time. Tumor growth was delayed 4 to 6 days by combined treatment of 5- fluorouracil and ultrasound (US). Ultrastructure investigations of tumor cells showed severe damage in cytoplasmic organelles and cytoplasmic vacuoles that increased with increasing ultrasonic intensity and sonocation time. This damage appears as prominent crowded vacuoles among swollen ruptured organelles, chromatin fragments and severe increase in numbers of pyknotic and apoptotic cells.

Protein A-induced apoptosis of cancer cells is effected by soluble immune mediators

Since Protein A (PA) of Staphylococcus aureus has been documented to have both antitumor and immunostimulatory properties, we attempted to determine whether PA-induced tumor cell death was effected through the immune system of the host, and analyze the mechanisms of such anti-tumor activity. For in vivo studies, Ehrlich's ascites carcinoma (EAC) cells were inoculated into the peritoneal cavity of Swiss albino mice. PA (1 micro g/20 g body weight) was injected biweekly for 2 weeks. To determine the role of immunomodulators in PA-induced tumor cell death, EAC were co-cultured with PA-primed splenic cells or with the spent medium of the same. Our results indicated a "two-step" mechanism of the induction of apoptosis in tumor cells, by PA, i.e. (1) activation of the immune system of the host to release different apoptogenic factors like tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO); and (2) induction of EAC apoptosis by these soluble immune mediators through the up-regulation of pro-apoptotic factors (p53 and Bax) and down-regulation of anti-apoptotic factor (Bcl-2), resulting in the activation of caspase-3. The present observations provide additional findings on an approach to cancer immunotherapy that causes apoptogenic insult to cancer cells.

Cytokine profile of Ehrlich ascites tumor treated with Bothrops jararaca venom

We previously demonstrated that Bothrops jararaca venom (BjV) has an antitumor effect on Ehrlich ascites tumor (EAT) cells and induces an increase of polymorphonuclear leukocytes in early stages of tumor growth. It has been reported that this venom presents an important inflammatory effect when inoculated in animal models and in human snakebites, and that cytokine levels have been detected in these cases. To evaluate whether the cytokines can be involved with the suppression of the tumoral growth, we evaluate the cytokine profile in the peritoneal cavity of mice inoculated with EAT cells and treated with BjV. Swiss mice were inoculated with EAT cells by the intraperitoneal route and treated with BjV venom (0.4 mg/kg, intraperitoneally), on the 1st, 4th, 7th, 10th, and 13th day. Mice were evaluated for cytokine levels on the 2nd, 5th, 8th, 11th and 14th day. Analysis was performed using an enzyme-linked immunosorbent assay for interleukin (IL)-1alpha, IL-2, IL4, IL-6, IL-10, IL-13, and tumor necrosis factor-alpha (TNF-alpha) levels in the peritoneal washing supernatant. Results were analyzed statistically by the Kruskal-Wallis and Dunn's tests at the 5% level of significance. We observed that EAT implantation induces IL-6 production on the 11th and 14th days of tumor growth, IL-10 on the 11th day and TNF-alpha on the 14th day. The treatment with BjV suppresses production of these cytokines. In addition, IL-13 was produced by animals that were inoculated only with venom on the 11th and 14th days, and by the group inoculated with EAT cells and treated with venom on the 2nd and 14th days. Furthermore, we suggest that the IL-6 detected in the present study is produced by the EAT cells and the suppression of its production could be associated with the antitumor effect of BjV.

Superantigen-induced apoptotic death of tumor cells is mediated by cytotoxic lymphocytes, cytokines, and nitric oxide

The bacterial superantigen staphylococcal enterotoxin A (SEA) is a potent inducer of CTL activity and cytokine production in vivo. Protein A (PA) of Staphylococcal aureus has been found to have diverse biological response modifying properties and to possess antitumor, antitoxic and antiparasitic effects. In this study we examined the anti-tumor effect of these two superantigens used separately as well as in combination in mice carrying the Ehrlich ascites tumor. With combined treatment, DNA cell cycle analysis of tumor cells showed a significant (P < 0.05) percentage of tumor cell death. Levels of the soluble mediators TNF-alpha, IFN-gamma and IL-1 as well as NO were elevated. Additionally, CD4(+) and CD8(+) specific T cells in spleen, thymus and PBMC in tumor carrying mice were increased (P < 0.01). Our data altogether suggests that enhanced tumor cell death is caused by the increased CTL activity, cytokine and nitric oxide levels, in response to the combined effect of SEA + PA.

[Tumor growth index as an integral criterion for the efficacy of antineoplastic therapy under experimental conditions]

An additional criterion is suggested for description of effectiveness of therapy of experimental tumors--tumor growth index. It is a ratio of area covered by the kinetic curve of tumor growth in the study group and that in control. The index is intended to describe the efficacy of therapy in terms of degree and duration of the effect.

Electrochemical treatment of mouse Ehrlich tumor with direct electric current

Electrochemical treatment of cancer utilizes direct electric current (DEC) to produce direct alterations and chemical changes in tumors. However, the DEC treatment is not established and mechanisms are not well understood. In vivo studies were conducted to evaluate the effectiveness of DEC on animal tumor models. Ehrlich tumors were implanted subcutaneously in sixty male BALB/c mice. When the tumor volumes reached 850 mm(3), four platinum electrodes were inserted into the tumors. DEC of 4 mA was applied for 21 min to the treated group; the total charge was 5 C. The healthy and sick control groups were subjected to the same conditions but without DEC. Hematological and chemical parameters as well as histopathological and peritumoral findings were studied. After the electrochemical therapy it was observed that both tumor volume decrease and necrosis percentage increase were significant in the treated group. Moreover, 24 h after treatment an acute inflammatory response, as well as sodium ion decrease, and potassium ion and spleen weight increase were observed in this group. It was concluded that both electrochemical reactions (fundamentally those in which reactive oxygen species are involved), and immune system stimulation induced by cytotoxic action of the DEC could constitute the most important antitumor mechanisms.

[Therapeutic effects of adenovirus-bcl-xs gene to the ascites tumor of nude mice model of human ovarian carcinoma]

OBJECTIVE

To investigate the effects of adenovirus-bcl-xs gene on the ascites tumor growth inhibition and survival rate of nude mice with human ovarian carcinoma transplanted intraperitoneally.

METHODS

Making an adenovirus-bcl-xs gene vector infected in JH293T cell and reproduced in it. After having detected the inhibitory potential of adenovirus-bcl-xs gene on NUTU-19 cell we use it to transfer intraperitoneally to ascites tumor model of human ovarian carcinoma transplanted in nude mice. Detected the ascites formation, the survival time and survival rate of nude mice with the human ascites tumour. The weight and toxic-adverse systemically effects of nude mice was observed and morphology of adenovirus was observed by electromicroscope and the gene expression was detected by immunocell chemistry.

RESULTS

The adenovirus-bcl-xs gene could reproduce in JH293T cell and had inhibitory potential on NUTU-19 cell, the survival time of nude mice was longer and the survival rate was higher, and the time of ascites formation was retarted. There was no obvious alternation in the weight and systemic toxic-adverse effects observed.

CONCLUSIONS

The data suggests that the transfer of adenovirus-bcl-xs gene to the ascites tumour of nude mice with human ovarian carcinoma could improve the survival rate of nude mice and retard the time of ascites formation. It may be a useful method of gene therapy in the treatment of ovarian carcinoma.

Suppression of Ehrlich subcutaneous solid tumor growth by immunization with ganglioside GT1b of its origin, its IgM antibody or anti-idiotype antibody

Mice vaccinated with purified Ehrlich tumor-plasma GT1b admixed with Freund's adjuvant suppressed subcutaneous growth of the same tumor cells inoculated in vivo by 37.9%. The suppression was dose-dependent and was a result of humoral immune response against GT1b. Further, when mice were injected with varying doses of rabbit polyclonal anti-GT1b IgM antibody and challenged with Ehrlich tumor cells subcutaneously, a significant reduction in tumor growth (47.3%) was observed. Again, the suppression was dose-dependent. To strengthen furthier the observed therapeutic potential of this immunogenic GT1b, mice were immunized with anti-idiotype antibodies to GT1b raised in female Sprague Dawley rats by immunization with rabbit anti-GT1b IgM, which is expected to carry the structural image of GT1b. Immunization of mice with this anti-idiotype antibody was observed to suppress Ehrlich subcutaneous solid tumor growth by 60%. The results indicated therapeutic potential of immunogenic tumor-associated ganglioside in solid tumor model.

Induction of blebbing in Ehrlich ascitic adenocarcinoma cells during in vitro hyperthermia

We studied the effect of in vitro hyperthermia on induction of blebbing in cultured Ehrlich ascitic adenocarcinoma cells. Hyperthermia (42-48 degrees C) promotes induction of blebbing in cell culture, but this induction is reversible, and cessation of hyperthermia leads to almost complete recovery of the morphological composition of cell suspension.

Suppression of Ehrlich ascites tumor growth by immunization with ganglioside GT1b of its origin, its IgM antibody or anti-idiotype of the anti-GT1b IgM

Ehrlich tumor expresses the ganglioside GT1b. The plasma of mice with Ehrlich ascites tumor burden also contains GT1b. The structural identity of plasma GT1b was ascertained by a series of enzymatic degradation and mass spectral analysis. Mice were vaccinated with purified plasma GT1b admixed with Freund's adjuvant (FA). Sixty nine percent suppression of Ehrlich ascites tumor growth was observed in vaccinated mice. The suppression was dose-dependent. It is hypothesized that the tumor growth-suppression is a result of immune response to GT1b Humoral immune response to GT1b was demonstrated by passive hemagglutination assay of the sera of vaccinated mice. To test the hypothesis, the mice were administered with rabbit polyclonal anti-GT1b IgM antibody in varying doses and challenged with Ehrlich tumor. A significant reduction in tumor growth (65%) was observed in mice administered with anti-GT1b IgM antibody. Again, the suppression was dose-dependent. To verify further, another batch of mice was immunized with anti-idiotypic antibodies to rabbit anti-GT1b IgM raised in rat. The polyclonal anti-idiotype antibody is expected to carry the structural image of GT1b. In a dose-dependent manner, a maximum of 82% suppression of tumor growth was observed in mice immunized with the anti-idiotype antibody. This observation further strengthened the hypothesis that ganglioside mediated suppression of tumor growth may be a result of immunogenicity of the target ganglioside. This was also supported by positive reaction of the sera of anti-idiotype vaccinated mice with both anti-idiotype antibody and ganglioside GT1b in passive hemagglutination assay. The results favour the therapeutic potential of immunogenic tumor-associated gangliosides.

Efficient in vivo gene delivery by the negatively charged complexes of cationic liposomes and plasmid DNA

We examined changes in zeta potential (the surface charge density, zeta) of the complexes of liposome (nmol)/DNA (microg) (L/D) formed in water at three different ratios (L/D=1, 10 and 20) by changing the ionic strength or pH to find an optimum formulation for in vivo gene delivery. At high DNA concentrations, zeta of the complexes formed in water at L/D=10 was significantly lowered by adding NaCl (zeta=+8.44+/-3.1 to -27.6+/-3.5 mV) or increasing pH from 5 (zeta=+15.3+/-1.0) to 9 (zeta=-22.5+/-2.5 mV). However, the positively charged complexes formed at L/D=20 (zeta=+6.2+/-3.5 mV) became negative as NaCl was added at alkaline pH as observed in medium (zeta=-19.7+/-9.9 mV). Thus, the complexes formed in water under the optimum condition were stable and largely negatively charged at L/D=1 (zeta=-58.1+/-3.9 mV), unstable and slightly positively charged at L/D=10 (zeta=+8.44+/-3.7 mV), and unstable and largely positively charged at L/D=20 (zeta=+24.3+/-3.6 mV). The negatively charged complexes efficiently delivered DNA into both solid and ascitic tumor cells. However, the positively charged complexes were very poor in delivering DNA into solid tumors, yet were efficient in delivering DNA into ascitic tumors grown in the peritoneum regardless of complex size. This slightly lower gene transfer efficiency of the negatively charged complexes can be as efficient as the positively charged ones when an injection is repeated (at least two injections), which is the most common case for therapy regimes. The results indicate that optimum in vivo lipofection may depend on the site of tumor growth.

Passive immunotherapy of mice bearing Ehrlich ascites tumor expressing human, membrane-bound placental alkaline phosphatase

The objective of our study was to test if a tumor expressing a transgene coding for a membrane-bound protein is amenable to immunotherapy by antibodies to the same protein. To this end, we have established an Ehrlich ascites tumor (EAT) cell line, EAT-DAP, stably expressing human, membrane-bound placental alkaline phosphatase (PLAP) by infecting EAT cells (EATC) with the retroviral vector DAP and selecting neomycin-resistant cells. EATC and EAT-DAP cells grew at similar rates in vitro, and produced ascites tumor in Swiss-Webster mice with similar efficiency. We have treated mice bearing EAT-DAP ascites tumor with a mouse monoclonal antibody to human PLAP or with a monoclonal antibody to human C proteins of the heterogenous ribonucleoprotein complex (hnRNP). The average survival of mice treated with anti-hnRNP was 16.4 +/- 1.1 days (n = 8). Treatment with anti-PLAP prolonged the survival of mice; in 4 mice average survival was 23.3 +/- 5.7 days. Four animals, however, survived for 60 days when they were killed and had no visible signs of tumor. These data support the notion that passive immunotherapy using antibodies against a membrane protein, expressed in tumor cells transduced by a viral vector coding for that protein, may be effective in controlling tumor growth.

Correlation and modulation of Ehrlich ascites tumor growth with tumor-plasma IgA

Plasma IgA level of Ehrlich ascites tumor bearing mice showed correlation with progress of tumor growth. In PAGE analysis total plasma IgA separated into 3 major bands corresponding to mol. wt. > or = 669,000 daltons, identical to 443,000 daltons and between 443,000 and 150,000 daltons. All the three bands increased gradually with progress of tumor growth upto day 14 and then declined on day 16. Total plasma IgA isolated by anti-IgA affinity chromatography when adoptively transferred to mice inhibited tumor growth. Affinity-purified plasma IgA separated into three major peak fractions after Sephadex G-200 column chromatography which corresponded with the bands of IgA on PAGE analysis. Three Sephadex G-200 IgA fractions when adoptively transferred to tumor-bearing mice showed effect different from total IgA. High mol. wt. IgA fraction (> or = 669,000 daltons) inhibited tumor growth whereas medium mol. wt. fraction (identical to 443,000 daltons) enhanced tumor growth. The low mol. wt. IgA fraction (< 443,000 and > 150,000 daltons) had no significant effect on tumor growth. The high mol. wt. IgA fraction enhanced tumor killing ability of peripheral blood lymphocytes (PBL) and peritoneal macrophages of tumor bearer in vitro. Medium mol. wt. IgA fraction inhibited tumor-killing ability of PBL in vitro but had no significant effect on peritoneal macrophages. The low mol. wt. IgA fraction showed a mild enhancing effect on tumor-killing ability of PBL but had no significant effect on peritoneal macrophages. The results established importance of IgA in tumor growth regulation and its therapeutic potentiality. The results indicated that tumor growth modulation by tumor plasma IgA is also mediated by its effect on cellular anti-tumor immune factors of the host.

Effect of a submaxillary gland extract on Ehrlich tumor growth in mice

Ablation of host submaxillary glands modifies Ehrlich tumor growth and tumor-infiltrating leukocytes, possibly by modifications in the serum level of growth factors produced by this gland. To extend this research, 7-month-old male EPM-1 mice (N = 30) were divided into two groups: 1) inoculated with tumor cells previously incubated with submaxillary salivary gland extract (SGE) in PBS for 30 min at 37%; 2) inoculated with tumor cells previously incubated with PBS, under the same conditions. Animals were inoculated into the footpad with 40 microl of a suspension containing 4.5 x 10(7) tumor cells/ml, and footpad thickness was measured daily for 10 days. Sections and smears of tumor cells were prepared from the tumor mass to determine mitosis frequency, percent of tumor cells immunopositive to nerve (NGF) and epidermal (EGF) growth factors and percent of tumor-infiltrating leukocytes. The incubation of tumor cells with SGE produced a tumor reduction of about 30% in size (P<0.01). This effect was not related to loss of cell viability during incubation, but a 33% increase (P<0.05) in the percentage of dead or dying tumor cells and a 15% increase in the percent of NGF/EGF-positive tumor cells (P<0.01) were observed in vivo at the end of experiment. Tumor-infiltrating lymphocytes and mitosis frequency did not differ between groups. These data suggest a direct effect of factors present in SGE on tumor cells, which induce degeneration of tumor cells.

The effect of skin transplantation on tumor growth in mice

BACKGROUND

Skin allograft is an immunostimulant. Skin allograft activates effector arms of the immune system including the cytotoxic T lymphocytes, activated macrophages, and natural killer cells. These cells may be involved in the destruction of tumor cells.

METHODS

Balb/c mice were divided into the study (n = 10) and control (n = 10) groups. Alloskin grafts 1 cm in diameter from the backs of Swiss albino mice were placed on the backs of balb/c mice (study group). The same size autoskin grafts from the backs of other balb/c mice were used for the control group. Fourteen days after grafting, we inoculated 1,000 Ehrlich ascites tumor cells intraperitoneally into both groups. Two days after tumor inoculation, we used secondary allografts and autografts (which were about 2 to 3 mm in diameter) for the same groups. We followed up graft survival and animal survival in both groups.

RESULTS

All 10 of the autografted mice died between the 18th and 25th days owing to malignancy. In the allografted group, 2 mice died (1 on day 17 and the other on day 23). Allograft rejection had not occurred in these 2 mice at the time of their death. The other 8 mice in the same group rejected allograft, on average within 9 days (9+/-3, median 8). These 8 mice were alive and without apparent health problems during the 4 months of follow-up.

CONCLUSION

Allo-skin graft rejection may help rejection of tumor cells and may be of use in immunotherapy of cancer.

On the inhibitory activities of a new boron compound and ultrasound against the mouse ascites tumour

The inhibitory effects of a new boron compound, dihydroxy (oxybiguanido) boron (III) hydrochloride monohydrate (HB), and ultrasound (US) of a frequency 25 kHz on the growth of ascites tumour in female Swiss mice were studied by monitoring the survival, weight of tumour-associated material, tumour cell count, serum alkaline phosphatase activity and the haematological parameters of the treated animals. 5-Fluorouracil (5-FU), a well-known anticancer agent, was used as positive control. While HB exhibited a very significant antitumour action, US alone produced a small but significant inhibitory effect. The combination of US with HB or 5-FU produced an extra antitumour action as compared to the actions of these chemicals used singly. The mechanisms of action of the new boron compound (HB) and US are discussed.

Glutathione reduces the toxicity associated with antitumor therapy of ascites fluid adsorbed over Staphylococcus aureus Cowan I in tumor bearing mice

It has been well documented in the literature that the removal of circulatory immune complexes (CICs) from the host circulation leads to the immunopotentiation as well as generation of antitumor responses in a variety of tumors in rats, cats, dogs and human patients. CICs are the major immunosuppressive factors in tumor bearing host. Protein A (PA) has been extensively used for the removal of these CICs from the sera/plasma of tumor bearers, because PA has the ability to bind with the Fc portion of mammalian immunoglobulins. Previously, we reported for the first time a potent antitumor response by the inoculation of cell free Ehrlich's ascites fluid adsorbed in vitro over PA containing Staphylococcus aureus Cowan I (SAC) in Ehrlich's ascites tumor model. However, there was toxicity associated with this form of therapy in terms of early death of treated animals and the depletion of hepatic glutathione pool as well as phase I biotransformation enzyme and increase in glutathione-S-transferase (GST) activities. In the present investigation, tumor bearing animals were treated intraperitoneally (i.p.) on alternate days for 15 days with adsorbed ascites fluid (ad-ASF) (0.1 ml) and glutathione (GSH) (250 mg/kg body weight) separately. We found that GSH supplementation increases mean survival time of GSH and ad-ASF treated mice up to 37.2 days in comparison with 19.9 days for only ad-ASF treated animals, while percent increase in body weight was found to be not affected by the GSH substitution, which remains significantly lower (P < 0.01) in comparison to the tumor control animals. GSH supplementation causes a significant decrease (P < 0.05) of glutathione-S-transferase and restoration of aniline hydroxylase activity (P < 0.05) and aminopyrine-N-demethylase activity. We have also observed that GSH supplementation does not alter the tumor cell viability and tumor cell counts in ad-ASF treated animals in comparison to only ad-ASF treated animals, which indicates that GSH supplementation does not alter the antitumor effect of the therapy. Treatment of Ehrlich's ascites tumor bearing mice with ad-ASF and glutathione increased their survival, but did not reduce the mortality of animals because of tumor.

On the possible use of a new boron compound, hydroxysalicylhydroxamato boron(III), and ultrasound in the treatment of female mice bearing the Ehrlich ascites carcinoma cells

The inhibitory effects of a new boron compound, hydroxy salicylhydroxamato boron (III) (SHB) and ultrasound of frequency 25 KHz (US) on the growth of ascites tumor in female Swiss mice were studied by monitoring the survival and the tumor growth in the treated tumor bearing mice and also the transplantability and the DNA synthesis in the treated tumor (Ehrlich ascites carcinoma) cells. While SHB alone produced a highly significant antitumor activity, US alone produced a small but significant effect. The combination of SHB and US produced significantly greater antitumor activity than SHB alone. The mechanisms of SHB and US actionary are discussed.

Antitumor effect of vitamin D-binding protein-derived macrophage activating factor on Ehrlich ascites tumor-bearing mice

Cancerous cells secrete alpha-N-acetylgalactosaminidase (NaGalase) into the blood stream, resulting in deglycosylation of serum vitamin D3-binding protein (known as Gc protein), which is a precursor for macrophage activating factor (MAF). Incubation of Gc protein with immobilized beta-galactosidase and sialidase generates the most potent macrophage activating factor (designated GcMAF). Administration of GcMAF to cancer-bearing hosts can bypass the inactivated MAF precursor and act directly on macrophages for efficient activation. Therapeutic effects of GcMAF on Ehrlich ascites tumor-bearing mice were assessed by survival time and serum NaGalase activity, because serum NaGalase activity was proportional to tumor burden. A single administration of GcMAF (100 pg/mouse) to eight mice on the same day after transplantation of the tumor (5 x 10(5) cells) showed a mean survival time of 21 +/- 3 days for seven mice, with one mouse surviving more than 60 days, whereas tumor-bearing controls had a mean survival time of 13 +/- 2 days. Six of the eight mice that received two GcMAF administrations, at Day 0 and Day 4 after transplantation, survived up to 31 +/- 4 days whereas, the remaining two mice survived for more than 60 days. Further, six of the eight mice that received three GcMAF administrations with 4-day intervals showed an extended survival of at least 60 days, and serum NaGalase levels were as low as those of control mice throughout the survival period. The cure with subthreshold GcMAF-treatments (administered once or twice) of tumor-bearing mice appeared to be a consequence of sustained macrophage activation by inflammation resulting from the macrophage-mediated tumoricidal process. Therefore, a protracted macrophage activation induced by a few administrations of minute amounts of GcMAF eradicated the murine ascites tumor.

Thermoradiotherapy with hydralazine: the effect of preirradiation of the tumor bed on blood flow and growth delay of Ehrlich carcinoma

Ehrlich carcinoma transplanted into preirradiated calf muscle of mice was used as a model for tumor recurrence after unsuccessful radiotherapy. Due to the tumor bed effect (TBE), these grafts grew more slowly than control tumors implanted in the unirradiated tissue. When these tumors achieved the same volume (0.3-0.4 cm3), in 10-11 days for tumors implanted in irradiated tissue and 7-8 days for control tumors, they were treated with radiation, the tumor blood flow inhibitor hydralazine, and hyperthermia, alone or in different combinations. In the case of the trimodality treatment, single irradiation of tumors at a dose of 12.5 Gy was followed 2.5-3 h later by administration of hydralazine (2.5 mg/kg) and local hyperthermia (water bath, 43 degrees C for 30 min). The growth delay induced in the different tumor types by irradiation, hydralazine and hyperthermia, alone or in different combinations, was related to the blood flow measured in the tumors by the 133Xe clearance technique 24-48 h after treatment. It was shown that the reduction of blood flow after treatment with hyperthermia or hydralazine was approximately equal in both types of tumors. However, the combined inhibiting effect of these agents differed in the tumors: It was synergistic in control tumors and close to additive in tumors implanted in irradiated tissue. In terms of the specific tumor growth delay, the latter tumors were slightly more sensitive to hyperthermia, but were more resistant to radiation and thermoradiotherapy compared to control tumors. Hydralazine potentiated the tumoricidal effects of heat alone and heat combined with radiation. The enhancement was more substantial in control tumors compared to tumors implanted in irradiated tissue. A general correlation between the hydralazine-induced enhancement of the effects of heat on tumor blood flow and growth delay was observed. In tumors implanted in irradiated tissue, the inhibition of perfusion after treatment with hydralazine plus hyperthermia was smaller, and presumably a less marked treatment response to these agents (with or without radiation) was therefore achieved as a result in these tumors compared to the control tumors.

Intratumoral cisplatin administration in electrochemotherapy: antitumor effectiveness, sequence dependence and platinum content

Electrochemotherapy using intratumoral cisplatin administration was tested on EAT tumors in mice. Mice were treated with eight electric pulses (100 micros, 1 Hz, 1040 V) and/or cisplatin (1, 2, 4 and 8 mg/kg). Cisplatin treatment resulted in up to 20 days of tumor growth delay. Electrochemotherapy resulted in tumor cures; local tumor control reached a plateau at 4 mg/kg in 67% of tumor cures. The maximal effect of electrochemotherapy was achieved when cisplatin was injected 5 min before or simultaneously with electric pulses application. Approximately two times more platinum was bound to DNA in electrochemotherapy than in cisplatin treated tumors at all time points tested. Our study shows that electrochemotherapy with intratumoral cisplatin administration is a very effective local treatment of EAT tumors with high curability rate.

Synergism of dimethoxybenzosemiquinone free radicals and CD4+ T-lymphocytes to suppress Ehrlich ascites tumor

Numerous natural and synthetic quinone compounds possess significant antitumor properties. Various mechanisms have been proposed to account for these properties, including scission and degradation of tumor cell DNA, intracellular "redox cycling" to cogenerate semiquinone free radicals and reactive oxygen intermediates, and the interaction of semiquinone radicals with tumor cell surface flavoenzymes. However, no evidence has been presented to explain adequately the preferential attack on tumor cells by semiquinone radicals, as opposed to normal cells. To address this question, a synergistic interaction was examined. A therapy consisting of a mixture of L-ascorbate and 2,6-dimethoxy-p-benzoquinone, was used for in vivo evaluation. BALB/c mice were depleted of functional T-lymphocytes by xenogeneic monoclonal antibody pretreatment, challenged with Ehrlich ascites tumor, and administered the semiquinone radical-generating therapy. Mice depleted of CD4+ T-lymphocytes responded with rapidly fatal tumor progression, with significantly decreased mean survival times over controls, whereas less severe responses were observed in mice devoid of CD8+ T-lymphocytes. Mice depleted of both T-lymphocyte subpopulations responded with uninhibited tumor growth and rapid mortalities. When tumor challenge occurred after therapy, tumor growth was significantly delayed in mice enriched for CD4+ T-lymphocytes, with demonstrable increases in mean survival time over controls. This reagent combination had no significant effect on T-lymphocyte profiles in secondary lymphoid organs. These data suggest a synergistic phenomenon of semiquinone radical-induced cytostasis coupled with T-lymphocyte helper activity for optimal tumor suppression.

Lipid peroxidation induced by ultrasonication in Ehrlich ascitic tumor cells

The mechanism of sonodynamic action in tumor cells is poorly investigated. It is known that ultrasound generates free radicals in phosphatidylcholine liposomes used as a membrane model. The participation of lipid peroxidation products in the mechanisms of physiological suppression of cell multiplication has been investigated for some tumor cells. In the present work ultrasound-induced lipid peroxidation in Ehrlich ascitic tumor cells was studied. Ultrasonication increased the level of lipid peroxidation quantified by the TBARS method in homogenates from Ehrlich ascitic tumor cells. Changes in the fatty acid composition of lipids from Ehrlich ascitic tumor cells irradiated by sonication were observed. TBARS production obtained by ultrasound was compared to TBARS production obtained by widely used chemical inductors. The free-radical processes evoked by ultrasound are of interest in antitumor therapy.

Thermosensitivity and thermotolerance in the adriamycin-resistant strain of Ehrlich ascites tumor cells

The acquisition of resistance to anticancer drugs is an important problem in cancer chemotherapy. Ehrlich ascites tumor cells (wild type EAT cells) were grown in a medium containing 1 microgram/ml adriamycin (ADR) (ADR-resistant strain) and the cells that proliferated were established in our laboratory. Intracellular ADR accumulation and the killing effect of ADR in the ADR-resistant strain were markedly reduced compared with those of the wild type EAT cells. In this study, we initially observed thermosensitivity in both strains and found no difference in the thermosensitivity. These findings demonstrated that hyperthermic treatment was effective in the ADR-resistant strain as well as in the wild type EAT cells. On the other hand, thermotolerance is an important problem in the hyperthermic treatment of cancer. We next observed the thermotolerance of both strains and found that the thermotolerance in the ADR-resistant strain was greater than that in the wild type EAT cells, but the thermotolerance was almost restored within 24 hours. Furthermore, we investigated the influence of thermotolerance on the intracellular accumulation and killing effects of ADR in the wild type EAT cells. There was no difference in the intracellular ADR accumulation and the killing effect of ADR between non-thermoresistant cells and thermoresistant cells. These results suggested that hyperthermia was effective in the ADR-resistant cells either alone or combination with ADR.