Anti-Tumor Activity of L-Erythro-α,β-dihydroxybutyraldehyde

L-Erythro -α,β-dihydroxybutyraldehyde has been shown to inhibit the incorporation of labelled leucine into protein of normal and neoplastic tissues, at a concentration which did not appreciably affect respiration and glycolysis. The present paper deals with the carcinostatic and carcinolytic activity of this drug against various tumors of mice and rats. The toxicity of L-erythro-α,β-dihydroxybutiraldehyde has been ascertained in mice and rats. Acute DL 50 values of the drug were 2.14 g/kg in mice and 1.62 g/kg in rat. Daily intraperitoneal injections of 500 mg/kg of L-erythro-α,β-dihydroxybutyraldehyde for seven days did not produce loss of weight or morphological lesions in control rats. The intraperitoneal administration of the drug in a dose of 250 mg/kg every 24 hours for seven days in Yoshida ascites hepatoma and in Walker ascites tumor-bearing rats (starting 24 hours after tumor transplantation) produced a complete disappearance of tumors. A daily dose of 500 to 750 mg/kg given intraperitoneally for seven days had a significant inhibitory effect on solid Ehrlich carcinoma and solid sarcoma 180 and increased significantly the average survival time of the animals bearing the same tumors in ascitic form. The drug was not effective on Oberling-Guérin solid or ascites myeloma. The results are briefly discussed.

Are the Showers of Cancer Cells in the Blood Responsible for an Increase in Metastases?

Showers of cancer cells were detected in the blood of animals bearing an experimental colon carcinoma of the rat following the administration of fluids into the tumor mass. These showers of cancer cells, however, persisted in the circulating blood only for a short period of time.

A significant increase in blood fibrinogen levels and a rapid consumption of factor VIII were also detected after surgery.

Hepatic metastases occurred in 9.2 % of the control animals, in 27.7 % of the sodium pentobarbital treated animals, and in 22.4 % of those inoculated with sodium chloride intratumor.

The significance of the presence of the showers of cancer cells into the circulating blood produced during these procedures, and the possibilities that these may increase metastases is discussed.

Evaluation of Bone Cancer Pain Induced by Different Doses of Walker 256 Mammary Gland Carcinoma Cells

BACKGROUND

Cancer pain is a complex medical syndrome. Understanding its underlying mechanisms relies on the use of animal models which can mimic the human condition. A crucial component of this model is the quantity of tumor cells; however, the exact relationship between the doses of tumor cells on bone cancer pain is yet unknown.

OBJECTIVE

We explored the relationship of different doses of Walker 256 carcinoma cells using a bone cancer pain model in rats, and evaluated its success and stability.

STUDY DESIGN

Experimental animal study using a comparative design.

SETTING

Experimental Animal Center and Tumor Institute of Traditional Chinese Medicine.

METHODS

We constructed the bone cancer pain model by implanting Walker 256 carcinoma cells into the right tibia of Sprague-Dawley (SD) rats (150 - 170 g). Spontaneous pain, mechanical threshold, and paw withdrawal latency (PWL) were measured and x-ray, bone mineral density (BMD), histological, interleukin-1 beta (IL-1beta) mRNA, carboxyterminal telopeptide of type I collagen (ICTP), and bone alkaline phosphatase (BAP) were analyzed for bone pain model evaluation.

RESULTS

The results showed that: (1) the 3 doses (3×105, 3.5×105, 4×105) of Walker 256 carcinoma cells can induce bone cancer pain from day 7 to day 21 after implantation into the right tibia of SD rats; (2) compared to the control group, 3×105, 3.5×105, and 4×105 Walker 256 carcinoma cells produced different pain manifestations, where the 3.5×105 dose of Walker 256 carcinoma cells resulted in the greatest bone cancer pain response; (3) the 3.5×105 dose induced the lowest mortality rate in rats; (4) Walker 256 carcinoma cells (3×105, 3.5×105, and 4×105) resulted in a significant decrease in the general condition and body weight of rats, where the 3.5×105 and 4×105 doses of carcinoma cells produced a greater effect than 3×105 dose of carcinoma cells; (5) progressive spontaneous pain, PWL, and mechanical threshold were exacerbated by 3.5×105 and 4×105 doses of carcinoma cells; (6) implantation of 3.5×105 and 4×105 doses of carcinoma cells induced progressive bone destruction and decrease in BMD; (7) ICTP and BAP were significantly increased following the implantation of 3.5×105 and 4×105 doses of carcinoma cells; (8) IL-1beta mRNA was significantly up-regulated in the spinal cord of rats implanted with 3.5×105 and 4×105 doses of carcinoma cells.

LIMITATIONS

One limitation of this study was the small sample size; therefore, additional research is needed to provide better validation. Another limitation is the unavailability of small animal Micro computed tomography (CT), which is a more advanced and precise technique in determining bone marrow density than the x-ray imaging system we used. In addition, ethology experiments during late-stage tumor progression can be more objective.

CONCLUSION

This study provides evidence that implantation of 3.5×105 and 4×105 dose of Walker 256 carcinoma cells produced the greatest effects in relation to the bone cancer pain model in SD rats, and 3.5×105 dose induced the lowest mortality rate.

KEY WORDS

Bone cancer pain model, Walker 256 carcinoma cells, different doses.

Tumor Susceptibility in Rats: Role of Infantile Manipulation and Later Exercise

Rat pups were removed from the nest briefly each day during the first week of life. Later experience with forced ambulation before and after implantation with the Walker carcinoma 256 was assessed for its effect on tumor size and survival of the animal. Exercise slowed tumor growth. Change in survival time resulting from exercise was not demonstrated in non-manipulated rats. Among manipulated animals, the group exercised both before and after implantation lived longer than rats exercised only after implantation. Infantile manipulation enhanced the exercise effect on tumor growth, and delayed mortality.

Exercise training decreases adipose tissue inflammation in cachectic rats

Bearing in mind that cancer cachexia is associated with chronic systemic inflammation and that endurance training has been adopted as a nonpharmacological anti-inflammatory strategy, we examined the effect of 8 weeks of moderate intensity exercise upon the balance of anti- and pro-inflammatory cytokines in 2 different depots of white adipose tissue in cachectic tumour-bearing (Walker-256 carcinosarcoma) rats. Animals were assigned to a sedentary control (SC), sedentary tumour-bearing (ST), sedentary pair-fed (SPF) or exercise control (EC), exercise tumour-bearing (ET), and exercise pair-fed (EPF) group. Trained rats ran on a treadmill (60% VO(2)max) 60 min/day, 5 days/week, for 8 weeks. The retroperitoneal (RPAT) and mesenteric (MEAT) adipose pads were excised and the mRNA (RT-PCR) and protein (ELISA) expression of IL-1β, IL-6, TNF-α, and IL-10 were evaluated. The number of infiltrating monocytes in the adipose tissue was increased in cachectic rats. TNF-α mRNA in MEAT was increased in the cachectic animals (p<0.05) in relation to SC. RPAT protein expression of all studied cytokines was increased in cachectic animals in relation to SC and SPF (p<0.05). In this pad, IL-10/TNF-α ratio was reduced in the cachectic animals in comparison with SC (p<0.05) indicating inflammation. Exercise training improved IL-10/TNF-α ratio and induced a reduction of the infiltrating monocytes both in MEAT and RPAT (p<0.05), when compared with ST. We conclude that cachexia is associated with inflammation of white adipose tissue and that exercise training prevents this effect in the MEAT, and partially in RPAT.

High Bcl-2/Bax ratio in Walker tumor cells protects mitochondria but does not prevent H2O2-induced apoptosis via calcineurin pathways

It has been previously shown that Walker 256 tumor cells express a high content of the anti-apoptotic protein Bcl-2 which protects mitochondria against the damaging effects of Ca(2+). In the present study, we analyze H(2)O(2)-induced apoptotic death in two different types of tumor cells: Walker 256 and SCC-25. Treatment with H(2)O(2) (4mM) increased reactive oxygen species generation and the concentration of cytosolic free Ca(2+). These alterations preceded apoptosis in both cell lines. In Walker cells, which show a high Bcl-2/Bax ratio, apoptosis was dependent on calcineurin activation and independent of changes in mitochondrial membrane potential (DeltaPsi(m)), as well as cytochrome c release. In contrast, in SCC-25 cells, which show a lower Bcl-2/Bax ratio, apoptosis was preceded by a decrease in DeltaPsi(m), mitochondrial permeability transition, and cytochrome c release. Caspase-3 activation occurred in both cell lines. The data suggest that although the high Bcl-2/Bax ratio protected the mitochondria of Walker cells from oxidative stress, it was not sufficient to prevent apoptosis through calcineurin pathways.

Ezrin/moesin in motile Walker 256 carcinosarcoma cells: Signal-dependent relocalization and role in migration

Rat Walker 256 carcinosarcoma cells spontaneously develop front-tail polarity and migrate in the absence of added stimuli. Constitutive activation of phosphatidylinositol-3 kinase (PI 3-kinase), Rac, Rho and Rho kinase are essential for these processes. Ezrin and moesin are putative targets of these signaling pathways leading to spontaneous migration. To test this hypothesis, we used specific siRNA probes that resulted in a downregulation of ezrin and moesin by about 70% and in a similar reduction in the fraction of migrating cells. Spontaneous polarization however was not affected, indicating a more subtle role of ezrin and moesin in migration. We provide furthermore evidence that endogenous ezrin and moesin colocalize with F-actin at the contracted tail of polarized cells, similar to ectopically expressed green fluorescent protein-tagged ezrin. Our results suggest that myosin light chain and ezrin are markers of front and tail, respectively, even in the absence of morphological polarization. We further show that endogenous ezrin and moesin are phosphorylated and that activities of PI-3 kinase, Rho and Rac, but not of Rho-kinase, are required for this C-terminal phosphorylation. Activation of protein kinase C in contrast suppressed phosphorylation of ezrin and moesin. Inhibition of ezrin phosphorylation prevented its membrane association.

[Preliminary study on biological behavior and staging of transplanted hepatoma in rats]

OBJECTIVE

To establish a staging standard for a transplanted hepatoma model in rats, which may be equivalent to the human primary liver cancer.

METHODS

A transplanted hepatoma model was made in SD rats by implantation of histologically intact Walker-256 tumor fragment into the left lateral lobe of the liver. The body weight, tumor volume and serum albumin level of the rats were measured and assayed in different periods. Pathological sections were also fabricated to detect the invasion and metastasis of the neighboring tissues.

RESULTS

The body weight loss and ascites occurred at the 12th and 18th day separately. The serum albumin level was (35.32+/-2.45) g/L at the 11th day, which showed no statistical difference as compared with the healthy rats (P>0.05), and the albumin level at the 18th day was significantly lower than that at the 11th day (P<0.05). At the 23rd day, 56.25% of the rats developed bloody ascites.

CONCLUSION

The period between 5-11 days in the model rats may be correspondent to the early stage of human primary liver cancer, and the biological behavior of the model rats at the18th day may be correspondent to the late stage of human primary liver cancer. This staging standard might be the guideline for model selection in experimental study of primary liver cancer.

Effects on Walker 256 tumour of carmustine associated with a cholesterol-rich microemulsion (LDE)

A cholesterol-rich microemulsion that binds to low-density lipoprotein (LDL) receptors (LDE), after injection into the bloodstream, concentrates in neoplastic tissues that over-express those receptors. LDE can thus serve as a vehicle for drug targeting. It was shown that carmustine side effects are pronouncedly reduced when the drug is associated with LDE in cancer patients. In this study, the therapeutic action of LDE associated with carmustine was compared with that of the non-associated drug in rats implanted with Walker 256 tumour. The toxicity and anti-tumour activity in rats treated with either free carmustine or carmustine associated with LDE and in control rats treated with saline solution were determined after a single intraperitoneal injection. The LD90 (90% lethal dose) of LDE-carmustine was 77 mg kg(-1) and of free carmustine was 44 mg kg(-1), indicating that LDE decreases toxicity. LDE-carmustine was able to decrease tumour mass at a lower dose level than free carmustine. Tumour regression time was shorter in LDE-carmustine- than in free carmustine-treated animals. Therefore, this study shows that the association of carmustine with LDE increases the therapeutic index of carmustine.

Design, synthesis and evaluation of novel 1,4-naphthoquinone derivatives as antifungal and anticancer agents

A series of 1,4-naphthoquinone derivatives were synthesized and tested for antifungal and antitumor activity against a number of fungal disease causative species and Walker 256 carcinoma cell lines. The results show that the compounds 8a,e and 11b possess pronounced antifungal profile where as 7b and f were found to be active against Walker 256 carcinoma cell lines. Moreover 7c and 11a showed inhibitory effect against reverse transcriptase enzyme from Rauscher Murine Leukemia Virus.

Overexpression of leukocyte-type 12-lipoxygenase promotes W256 tumor cell survival by enhancing alphavbeta5 expression

The metabolism of arachidonic acid (AA) leads to the generation of biologically active metabolites that have been implicated in cell growth and proliferation, as well as survival and apoptosis. We have previously demonstrated that rat Walker 256 (W256) carcinosarcoma cells express the platelet-type 12-lipoxygenase (12-LOX) and synthesize 12(S)- and 15(S)-HETE as their major LOX metabolites. Here we show that Walker 256 cells also express leukocyte-type 12-LOX and that its overexpression in these cells significantly extends their survival and delays apoptosis when cells are cultured under serum-free conditions. Under serum-free conditions, the expression of leukocyte-type 12-LOX is upregulated. 12-LOX-transfected W256 cells had a more spread morphology in culture compared with wild-type or mock-transfected cells. Examination of W256 cells showed that the cells expressed a number of integrins on their surface. Overexpression of 12-LOX enhanced the surface expression and focal adhesion localization of integrin alphavbeta5, while not affecting other integrins. Also, the 12-LOX-transfected W256 cells exhibited higher levels of microfilament content. Treatment of cells with monoclonal antibody to alphavbeta5 or cytochalasin B (a microfilament-disrupting agent), but not antibodies to other integrin receptors, resulted in significant apoptosis, characterized by rapid rounding up and detachment from the substratum. These results show that the 12-LOX pathway is a regulator of cell survival and apoptosis, by affecting the expression and localization of the alphavbeta5 integrin and actin microfilaments in Walker 256 cells.

Long-chain fatty acid uptake and oxidation in the perfused liver of Walker-256 tumour-bearing rats

AIMS/BACKGROUND

The effect of the Walker-256 tumour on uptake and oxidation of long-chain fatty acids was investigated in perfused livers of rats.

METHODS

Isolated livers were perfused in a non-recirculating system. Fatty acid uptake, ketogenesis, oxygen uptake and 14CO2-production were measured as well as the activities of the acyl carnitine transferases I and II (CAT I and CAT II).

RESULTS

Basal oxygen uptake of livers from tumour-bearing rats was lower. Ketone bodies production derived from the long-chain fatty acids in livers from starved tumour-bearing rats was lower relative to the controls, but 14CO2 production was similar in both groups. The oxygen uptake increment and the mitochondrial NADH/NAD+ redox ratio were also decreased in tumour-bearing rats. The extent of these differences was dependent on the chain length and structure of the fatty acid, the following decreasing sequence of differences between control and tumour-bearing animals being valid: palmitate > oleate > stearate. The CAT I activity of the enzyme isolated from livers of tumour-bearing rats was half that from normal rats when palmitoyl-CoA and oleoyl-CoA were the substrates.

CONCLUSIONS

Ketogenesis from exogenous fatty acids is decreased in the livers of Walker-256 tumour-bearing rats in consequence of the diminished activity of the mitochondrial CAT I. The lower rates of oxygen uptake indicate a decreased ATP synthesis, which is consistent with the in vivo lower phosphorylation potential.

Differences in cortical actin structure and dynamics document that different types of blebs are formed by distinct mechanisms

Bleb formation has been studied by specifically targeting major factors controlling this process, such as microtubule disassembly, local actin depolymerization, and increased pressure. At least two different types of blebs (types 1 and 2) formed by different mechanisms and possibly a third type (type 3) can be documented at the front of living polarized cells expressing green fluorescent protein-actin and/or in fixed and stained cells. Type 1 blebs (membrane/cortex dissociation blebs) formed by dissociation of the plasma membrane from cortical actin develop cytoplasmic actin layers associated with restriction rings. They can be induced by the microtubule-disassembling agent colchicine. Type 2 blebs (cortical actin disassembly blebs) form after disassembly of the cortical actin layer in the presence of latrunculin A. Restriction rings without a cytoplasmic actin layer occur in a transition zone between the intact cortical actin layer of the cell body and the compromised actin layer of the bleb. Evidence for a third type of bleb (type 3), showing an intact cortical actin layer but no cytoplasmic actin layer and no recognizable relationship between the actin cytoskeleton and the restriction ring, has been obtained by passive cell deformation in micropipettes, which increases pressure. Repolymerization of the cortical actin layer does not necessarily result in bleb retraction. Once formed, restriction rings do not narrow, suggesting that they result from isometric contraction. A simplified classification scheme has been developed to relate the type of bleb to specific signals or cell functions. Its application shows that spontaneously blebbing cells form almost exclusively type 1 blebs.

gamma-Linolenic acid and eicosapentaenoic acid induce modifications in mitochondrial metabolism, reactive oxygen species generation, lipid peroxidation and apoptosis in Walker 256 rat carcinosarcoma cells

The polyunsaturated fatty acids gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) are cytotoxic to tumour cells. GLA inhibits Walker 256 tumour growth in vivo, causing alterations in mitochondrial ultrastructure and cellular metabolism. The objective of the present study was to investigate the mechanisms behind fatty acid inhibition of Walker 256 tumour growth under controlled in vitro conditions. At a concentration of 150 microM, both GLA and EPA caused a decrease in cell proliferation and an increase in apoptotic index. Increases in reactive oxygen species (ROS) and lipid peroxide production were identified, as well as alterations in energy metabolism and the deposition of large amounts of triacylglycerol in the form of lipid droplets. Mitochondrial respiratory chain complexes I+III and IV had significantly decreased activity and mitochondrial membrane potential was greatly diminished. Intracellular ATP concentrations were maintained at 70-80% of control values despite the decreased mitochondrial function, which may be in part due to increased utilisation of glucose for ATP generation. Cytochrome c release from mitochondria was found, as was caspase-3-like activation. DNA fragmentation in situ revealed many apoptotic events within the cell population. The mechanism(s) by which ROS and lipid peroxides induce apoptosis remains unclear, but the effects of GLA and EPA appear to involve the mitochondrial pathway of apoptosis induction leading to cytochrome c release, caspase activation, loss of mitochondrial membrane potential and DNA fragmentation.

Differential cell death response to photodynamic therapy is dependent on dose and cell type

PDT-induced cell death, by either apoptosis or necrosis may vary with cell type or PDT dose. 5 cell types were treated with varying doses of aminolaevulinic acid-induced PDT and the type of cell death analysed. The mode of cell death was found to depend on both cell type and light dose. © 2001 Cancer Research Campaign www.bjcancer.com

The effect of an osteolytic tumor on the three-dimensional trabecular bone morphology in an animal model

OBJECTIVE

To investigate the application of micro-computed tomography (microCT) for the assessment of density differences and deterioration of three-dimensional architecture of trabecular bone in an experimental rat model for tumor-induced osteolytic defects.

DESIGN AND MATERIALS

Walker carcinosarcoma 256 malignant breast cancer cells (W256) were surgically implanted into the medullary canal of the left femur of 15 4-month-old rats. Twenty-eight days after surgery all animals were killed and both femora from each rat were harvested. A total of 30 specimens (left and right femur) were scanned in a desktop microCT imaging system (microCT 20, Scanco Medical) to assess densitometric and architectural parameters. For each specimen a total of 200 micro-tomographic slices with a resolution of 30 microns in the distal metaphysis was taken. Bone mineral content (BMC) was analyzed for both cortical and trabecular bone (ctBMC), and for trabecular bone only (tBMC). Architectural indices (BV/TV, Tb.N, Tb.Th, Tb.Sp) according to standard definitions used in histomorphometry were calculated for trabecular bone.

RESULTS

The quantitative analysis of density parameters revealed significantly (P < 0.001) lower values for ctBMC and tBMC in the tumor-bearing group (T) of 26% and 31%, respectively, compared with the contralateral control group. The quantitative analysis revealed significant (P < 0.001) changes in the architectural parameters in the tumor-bearing bones compared with the contralateral control group: BV/TV was 30% lower, Tb.N and BS/TV decreased by 24% and 21%, respectively, Tb.Th. decreased by 10% and Tb.Sp. increased by 94%.

CONCLUSIONS

This study demonstrates that microCT is able to provide three-dimensional parameters of bone mass and trabecular structure in an animal model for tumor-induced bone loss. Recent advances in therapeutic approaches for skeletal diseases such as osteoporosis and metastatic bone diseasse rely on an understanding of the effects of the agents on the mechanical properties of bone. In order to quantify the structural changes of the affected bones the application of a non-destructive method is mandatory. The use of microCT seems to be a great advantage, since biomechanical tests and further histologic analysis can be done for the same specimens.

Suction pressure can induce uncoupling of the plasma membrane from cortical actin

We tested the hypothesis that a pressure difference can cause blebbing associated with uncoupling of the plasma membrane from the cortical actin, a phenomenon found earlier in locomoting blebbing Walker carcinosarcoma cells. Untreated, initially spherical Walker carcinosarcoma cells were exposed to suction pressure by partial aspiration into micropipettes. The suction pressure required to induce blebbing was in the range of 0.9-3 cm H2O, i.e., somewhat lower than the increase in intracellular pressure measured before formation of protrusions in Amoeba proteus (Yanai et al., Cell Motil. Cytoskeleton 33, 22-29, 1996). The response was temperature-dependent, blebbing occurring more frequently at 37 degrees C than at room temperature. Blebbing was associated with formation of cytoplasmic actin layers, restriction rings and/or of gaps in the plasma membrane-associated cortical actin. The results support the view that blebbing associated with uncoupling of cortical actin and plasma membrane as observed in locomoting cells can be caused by a pressure gradient.

Redundancy of lamellipodia in locomoting Walker carcinosarcoma cells

Locomoting metazoan cells usually form lamellipodia at the leading front and it is widely accepted that lamellipodia are required for locomotion. In this case, suppression of lamellipodia must stop locomotion. However, the experiments show that lamellipodia are redundant for locomotion of Walker carcinosarcoma cells. Low latrunculin A concentrations (10(-7) M) transform polarised locomoting cells with lamellipodia into cells without morphologically recognisable protrusions showing an increased speed of locomotion and a reduced amount of cellular F-actin. Whereas untreated cells show a fairly linear distribution of F-actin along the plasma membrane, cells lacking morphologically recognizable protrusions at the front show modifications at the front consisting in an irregular distribution of F-actin with formation of small or large patches of F-actin alternating with small or large gaps in the F-actin layer. This is associated with a reduced resistance to deformation pressure at the front of the cell. High concentrations of latrunculin A (>10(-7) M) compromising contraction at the rear stop locomotion, suggesting that cortical contraction is important for locomotion to occur in these cells. The results are consistent with the view that actin polymerization is important for formation of lamellipodia but they are not compatible with the view that lamellipodia are essential for locomotion of Walker carcinosarcoma cells. A unifying hypothesis for the formation of different types of protrusions is proposed.

Suppression of bleb formation, locomotion, and polarity of Walker carcinosarcoma cells by hypertonic media correlates with cell volume reduction but not with changes in the F-actin content

The putative role of cellular or solvent volume in protrusive activity and locomotion has been investigated in blebbing Walker carcinosarcoma cells using hypertonic media. Blebbing, locomotion, and cell polarity are completely suppressed by 0.2 M sorbitol. The response occurs in two steps. In a first step, i.e. within 10 sec after the addition of sorbitol, blebbing and locomotion are inhibited and this is associated with an average cell volume reduction by 17% (corresponding to a reduction in solvent volume by 38%). It clearly precedes suppression of cell polarity (pre-existing protrusions, tail) occurring in a second step within 5 to 10 min after addition of sorbitol without additional reduction in the cell or solvent volume. The relative amount of F-actin does not correlate with the decrease in cell volume, suppression of blebbing, locomotion, and cell polarity. A significant decrease in the relative amount of F-actin is found only at volume reductions which are higher than those required to completely suppress blebbing, locomotion, and cell polarity. F-actin staining occurs preferentially along the cell membrane in isotonic as well as in hypertonic media. The results are best compatible with the hypothesis that hydrostatic pressure rather than actin polymerization at the front is the direct force driving the membrane forward during bleb formation. Cells with lamellipodia show a similar response to hypertonic media, suggesting that basically similar mechanisms may operate in both forms of protrusions.

The effect of nitrofurazone on the testes and accessory sex organs of normal rats and rats bearing the Walker carcinoma 256

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