Evaluation of Antitumor and Antioxidant Activity of Sargassum tenerrimum against Ehrlich Ascites Carcinoma in Mice

Context: In the last half century, discovering, developing and introducing of clinical agents from marinesources have seen great successes, with examples including the anti-cancer compound trabectedin. However,with increasing need for new anticancer drugs, further exploration for novel compounds from marine organismsources is strongly justified. Objective: The major aim of this study was to evaluate the antitumor and antioxidantpotential of Sargassum tenerrimum J.Agardh (Sargassaceae) on Ehrlich ascites carcinoma (EAC) in Swissalbino mice. Materials and Methods: An ethanol extract of S. tenerrimum (EEST) from whole algae was used toevaluate cytotoxicity followed by in vivo assessment of toxicity, using biochemical parameters including hepaticand non-hepatic enzymes. Antioxidant properties were examined in animals bearing EAC treated with dailyoral administration of 100-300 mg/kg extract suspension. Results: Antitumor effects of EEST in EAC bearingmice was observed with LD50 1815 mg/kg. Parameters like body weight, tumor volume, packed cell volume,tumor cell count, mean survival time and increase in life span in animals in the EAC bearing animals treatedwith EEST 300 mg/kg was comparable with control group. Significant differences were also seen with changesin total protein content, hepatic enzymes contents, MDA level, and free radical scavenging enzymes in untreatedvs. EEST treated group animals. Conclusions: Evaluation of antioxidant enzymes and hepatic enzymes in theEAC animal model treated with EEST exhibited similar effects as the positive control drug 5-flurouracil. S.tenerrimum extracts contain effective antioxidants with significant antitumor activity.     

Antioxidant properties of Rajgira (Amaranthus paniculatus) leaves and potential synergy in chemoprevention

In recent years there has been a substantial increase in the use of functional foods for disease control. Fruits and vegetables produce phytochemicals such as flavonoids and antioxidants which can lower oxidative stress and reduce the risk of chronic ailments like cancer. The aim of the present study was to investigate the antioxidant capacity and the possible protective effects of Amaranthus paniculatus leaves on the antioxidant defense system in Ehrlich's ascites carcinoma (EAC) -treated mice. Oral administration of the leaf extract at different doses caused a significant decrease in tumor volume, viable cell count and tumor weight and elevated the life span of EAC bearing mice. It also showed an improved antioxidant potential as evidenced by a significant increase in the cellular antioxidant defense system such as catalase, superoxide dismutase and reduced glutathione and also significantly reduced the levels of TBARS. The levels of RBC, hemoglobin and lymphocyte count were altered in EAC bearing mice and were reverted back to near normal levels after the treatment with the leaf extracts. Their adequate content of total phenolics and flavonoids, DPPH scavenging activity which further suggests that the extracts exert a significant protection against oxidative stress conditions.     

Antitumor effect of actinidia chinensis polysaccharide on murine tumor

A new polysaccharide compound (ACPS-R) has recently been isolated from the root of Actinidia Chinensis Planch. When given intraperitoneally to the transplantable tumor bearing mice at dose of 75-125 mg/kg, the tumor inhibition rate was more than 88.8% in Ehrilich ascitic cancer (EAC) or ascitic form of hepatoma (HepA) and more than 49.6% in solid hepatoma (HepS). The treatment effect of ACPS-R on EAC at dose of 15 mg/kg and 22.5 mg/kg, respectively. ACPS-R could also prolong the life of EAC-or P388-bearing mice, and increase the percentage of EAC-free mice. In addition, when ACPS-R was used in combination with 5-Fu, the antitumor effect was enhanced as compared with 5-Fu alone. A marked increase in cAMP levels and cAMP/cGMP ratio of spleen of EAC-bearing mice were observed after treatment of ACPS-R. The increase of both parameters nearly reached the normal levels of healthy mice. The increases of cAMP, cAMP/cGMP and tumor remission had statistical significance. It showed an intermediate inhibitory effect of ACPS-R on DNA synthesis by incorporating 3H-TdR into EAC cells. The results indicated that ACPS-R acts as a new antitumor polysaccharide, and the treatment effect of Actinidia root in folk medicine is probably related to ACPS-R.     

The antitumor effect of intraperitoneal treatment with rhTNF-alpha muteins on Ehrlich ascites tumor growth

The intraperitoneal (i.p.) treatment with recombinant human tumor necrosis factor-alpha (rhTNF-alpha) is one of the possible therapies for tumors that are confined to the abdominal cavity. Clinical trials aiming at the exploitation of the antitumor effects of rhTNF-alpha have been largely disappointing. In this model the activity of some rhTNF-alpha derivatives was studied. Ehrlich's ascites tumor (EAT) bearing Swiss albino male mice were treated i.p. three times a week with 10 micrograms/mice of rhTNF-alpha, mutein V or mutein VI for two weeks, starting on the 4th day after tumor inoculation. Control mice received PBS. The effect of the rhTNF-alpha derivatives on the course of EAT was evaluated basing on: total ascites volume (TAV); packed cell volume (PCV); total packed cell volume (TPCV); inhibitory growth rate (IGR); cellular population of EAT fluid; morphological EAT cell changes and mean survival time (MST). In the study mutein VI had only a slight effect on MST but significant on TAV- and TPCV-IGR (p < 0.001). In mice treated with rhTNF-alpha and mutein V the enhancement of MST (p < 0.01) was accompanied by TAV- and TPCV-IGR (p < 0.001). The number of EAT cells in ascites decreased after rhTNF-alpha and mutein V administration (p < 0.001). We conclude that treatment with high-dose of this modified molecule lacking the possibility of binding with p75R and not producing so intensified side effects is likely to find wider application in therapy and prevent the ascites growth just as rhTNF-alpha dosage.     

Evaluation of toxicity of beta-tethymustine, a new anticancer compound, in mice.

The toxicity of beta-tethymustine, a potential anticancer compound 1 ((Cancer Lett., 119 (1997) 7-12) was assessed in normal as well as in Ehrlich ascites carcinoma (EAC), Sarcoma-180 (S-180) and Dalton' s Lymphoma (DL) tumour-bearing Swiss male mice by measuring drug-induced changes in haematological parameters, femoral bone marrow cellularity and splenic cellularity on days 9, 15 and 21 following drug treatment at the optimum dose of 8.0 mg/kg body weight from days 1 to 7. Detailed studies were also made by noting sequential changes in the above parameters in normal and EAC-bearing mice on days 12 and 18, respectively. The results indicate that the compound did not adversely affect haematopoiesis as it was observed that no significant decrease in haematological parameters and femoral marrow cellularity occurred in treated groups. Initial hyposplenic activity was, however, noted in EAC and normal treated groups on day 9 which soon reached normal count within 7-10 days after termination of drug therapy. Drug-induced hepatotoxicity and nephrotoxicity were also sequentially evaluated in normal and tumour-bearing mice on days 9, 15 and 21 but no such toxicities were detected. Also, body weight, skin and hair texture, and behavioural pattern (food and water intake and activity) did not reflect any toxic reaction in host mice at this optimum dose.     

Evaluation of cisplatin combined with ondansetron in Ehrlich ascites carcinoma in vitro and in vivo

AIMS AND BACKGROUND: Nausea and vomiting occur in the majority of patients receiving cisplatin (CDDP) chemotherapy. Ondansetron, a new 5-HT3 receptor antagonist, has been used effectively to control CDDP-induced nausea and vomiting. This study examined the potential of ondansetron to interfere with CDDP antitumor activity and toxicity in Ehrlich ascites carcinoma (EAC). METHODS: The influence of ondansetron on CDDP cytotoxicity was evaluated using EAC cells in culture. In addition, the influence of ondansetron pretreatment on CDDP-induced antitumor activity and host tissue toxicity was studied in EAC-bearing mice. RESULTS: Ondansetron (0.25 microM) enhanced CDDP (0-32 microM) cytotoxicity against EAC cells in vitro. In EAC-bearing mice ondansetron (0.2 mg/kg,ip) administered 1 h before CDDP (7 mg/kg, ip) did not modify the antitumor activity of CDDP. CDDP (7 mg/kg, ip) single treatment induced significant increases in blood urea nitrogen (2-fold) and serum creatinine (2.5-fold) and significant decreases in hematocrit (25%) and white blood cell count (39%) compared to saline treatment. Mice receiving ondansetron 1 h before CDDP showed no significant enhancement of CDDP-induced nephrotoxicity or myelosuppression compared to those pretreated with saline receiving the same dose of CDDP. CONCLUSIONS: This study suggests that the use of ondansetron to control CDDP-induced nausea and vomiting does not affect CDDP antitumor efficacy.     

Antitumor and Cytotoxic Activities of Methanol Extract of Indigofera linnaei Ali.

Methanol extract of Indigofera linnaei (MEIL) was investigated for antitumor, cytotoxic and antioxidantactivities against transplantable tumors and human cancer cell lines. In vitro cytotoxicity was evaluated in HeLa,Hep-2, HepG-2, MCF-7, HT-29, Vero and NIH 3T3 cells by MTT assay and in vivo antitumor activity with Ehrlichascites carcinoma (EAC) and Dalton’s ascites lymphoma (DLA) tumor-bearing mice. Activity was measuredby monitoring the mean survival time, effect on hematological parameters, antioxidant enzyme levels and solidtumor volume. The extract exhibited strong in vitro cytotoxicity against all the tested cancer cell lines, but itwas found to be safe with normal cells. MEIL at the dose of 200 and 400 mg/kg, significantly increase the meansurvival time (P<0.001), exerted a protective effect on the hemopoietic system, demonstrated in vivo antioxidantactivity and significantly reduce solid tumor volume (P<0.01). These results show a significant antitumor andcytotoxic effect of MEIL against EAC, DLA and human cancer cell lines and support the ethnomedical use ofIndigofera linnaei.     

Grape seed extract inhibits advanced human prostate tumor growth and angiogenesis and upregulates insulin-like growth factor binding protein-3

Dietary intake of many fruits and vegetables has been shown to be associated with reduced risk of cancer. We investigated the in vivo efficacy of grape seed extract (GSE, patented as Traconol) against prostate cancer (PCA) and associated molecular events. Athymic nude mice were implanted with hormone-refractory human prostate carcinoma DU145 cells and fed with 100 and 200 mg/kg/day (5 days/week) doses of GSE for 7 weeks. At the end of experiment, tumors were immunohistochemically analyzed for cell proliferation, apoptosis and angiogenesis. Our data show that GSE feeding strongly inhibited tumor growth that accounted for 59-73% (p < 0.001) inhibition in tumor volume and 37-47% (p < 0.05) decrease in tumor weight at the end of the experiment. It did not show any significant change in body weight gain profile and diet consumption. Immunohistochemical analysis of tumors showed that GSE decreases proliferation index by 51-66% (p < 0.001) and increases apoptotic index by 3-4-fold (p < 0.001). CD31 staining for endothelial cells, showed decrease in intratumoral microvasculature in GSE-fed group of mice. Control tumors showed 64.0 +/- 1.6 CD31 positive cells/400x field compared to 23.2 +/- 0.9 and 15.7 +/- 0.08 (p < 0.001) CD31 positive cells in 100 and 200 mg/kg doses of GSE-treated tumors, respectively. GSE strongly inhibited (47-70%, p < 0.05) vascular endothelial growth factor (VEGF) secretion in conditioned medium by DU145 cells. Recently, the circulating level of insulin-like growth factor binding protein (IGFBP)-3 is shown to inversely related with PCA risk, growth and prognosis. Consistent with this, we observed 6-7-fold (p < 0.001) increase in tumor-secreted levels of IGFBP-3 after GSE feeding. In other immunohistochemical studies, compared to controls, tumor xenografts from GSE-fed groups of mice showed a moderate decrease in VEGF but an increase in IGFBP-3 levels. These findings suggest that GSE possesses in vivo anticancer efficacy against hormone-refractory human PCA, which is associated with its antiproliferative, proapoptotic and antiangiogenic activities together with upregulation of IGFBP-3.     

Antitumor activity of Nitronaphthal-NU, a novel mixed-function agent

Nitronaphthal-NU (Compound 1) was synthesized as a mixed-function antitumor agent based on the structures of the clinical drug CCNU and experimental compound Mitonafide. In vitro screening in four human tumor cell lines namely SNB-78 CNS, HOP-62 Lung, T47D Breast and SiHa - cervix revealed significant cytotoxicity in the former two cell lines much greater than CCNU and comparable to Mitonafide used as standards. In vivo antitumoral potency assessed in the murine ascites tumors Sarcoma-180 (S-180) and Ehrlich ascites carcinoma (EAC) by measuring the increase in median survival times of drug treated (T) over untreated control (C) mice, revealed highly significant (p<0.001) tumor regression effects greater than standards. Life span of mice bearing advanced tumor for 10 days before the drug challenge was also considerably increased. Its toxicity was assessed in vivo in normal and S-180 bearing mice by measuring drug-induced changes in haematological parameters, femoral bone marrow and splenic cellularities as well as hepatotoxicity and nephrotoxicity sequentially on days 9, 15 and 21 following drug treatment at the optimum dose of 50 mg/kg from day 1 to 7. Results indicate that it did not adversely affect haematopoiesis. The other parameters were within normal limit. The compound comparable to standards inhibited the synthesis of DNA and RNA in S-1 80 tumor cells.     

Poly-L-Lysine Inhibits Tumor Angiogenesis and Induces Apoptosis in Ehrlich Ascites Carcinoma and in Sarcoma S-180 Tumor

Background: This study focuses on the role of Poly-L-lysine (PLL), an essential amino acid, on molecular changes of tumor angiogenesis suppression, pro-apoptotic and anti-apoptotic gene expression after treatment on Ehrlich ascites carcinoma (EAC) and solid sarcoma-180 tumor cells bearing mice. Materials and Methods: The cell viability was carried out using MTT assay. The antitumor activity was evaluated by treatment with PLL at 20 and 40mg/kg/b.w doses for 14 days in EAC ascites tumor and 21 days for Sarcoma-180 solid tumor model. Several tumor evaluation studies, haematological and biochemical parameters were estimated. Importantly, the tumor cell apoptosis was assessed using microscopic observations, DNA fragmentation assay, Flow cytometric analysis, cell-cycle and electron-microscopic study, following which, the expression of several signal proteins related to pro-apoptosis, anti-apoptosis and tumor angiogenesis were quantified using western blotting and immunohistochemistry study. Results: Precisely, PLL had cytotoxic effect on K562; A549; U937 and B16F10 cancer cells. Significant decreases in liquid and solid tumors and increased life span of treated mice were observed (P<0.05). Typical morphological changes, apoptosis bleb phenomenon and sub-G1 cell cycle arrests revealed that PLL promoted apoptotic cell death. Western blot and immunohistochemistry confirms, PLL activated apoptotic signalling cascades through down regulation of Bcl-2 and CD31 protein and up-regulation of Bax and p53 proteins. The anti-angiogenic effects were also accompanied with decreased VEGF expression and reduced peritoneal-angiogenesis and microvessel density. Conclusions: The antitumor and antitumor-angiogenic activity of PLL was confirmed from all the results via up and down regulation of relevant signal proteins reported in this publication.     

Novel Mononuclear Ruthenium(II) Compounds in Cancer therapy

The present study was conducted to evaluate in vivo anticancer activity of two novel mononuclear ruthenium(II)compounds, namely Ru(1,10-phenanthroline)2(2-nitro phenyl thiosemicarbazone)Cl2 (Compound R1) andRu (1,10-phenanthroline)2(2-hydroxy phenyl thiosemicarbazone)Cl2 (Compound R2) against Ehrlich ascitescarcinoma (EAC) mice and in vitro cytotoxic activity against IEC-6 (small intestine) cell lines and Artemiasalina nauplii using MTT [(3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide)] and BLT [brineshrimp lethality] assays respectively. The tested ruthenium compounds at the doses 2 and 4 mg/kg body weightshowed promising biological activity especially in decreasing the tumor volume, viable ascites cell counts andbody weights. These compounds prolonged the life span (% ILS), mean survival time (MST) of mice bearing-EAC tumor. The results for in vitro cytotoxicity against IEC-6 cells showed the ruthenium compound R2 to havesignificant cytotoxic activity with a IC50 value of 20.0 μg/mL than R1 (IC50=78.8μg/mL) in the MTT assay and theLC50 values of R1 and R2 compounds were found to be 38.3 and 43.8 μg/mL respectively in the BLT assay. Thebiochemical and histopathological results revealed that there was no significant hepatotoxicity and nephrotoxicityassociated with the ruthenium administration to mice.     

Effect of altered lighting regimens, time-limited feeding, and presence of Ehrlich ascites carcinoma on the circadian rhythm in DNA synthesis of mouse spleen.

The objectives of the series of experiments described were (a) to determine whether there was a circadian rhythm in the incorporation of tritiated thymidine into DNA of the spleen in mice kept on a conventional light-dark cycle and fed ad libitum, (b) to study the effect that different light-dark cycles and a time-limited feeding schedule had on this circadian rhythm, (c) to ascertain what effect the presence of an 8-day Ehrlich ascites carcinoma (EAC) had on the rhythm in DNA synthesis in the spleen and what effect the EAC had on the circadian rhythm in the mitotic index in the corneal epithelium, and (d) to determine whether there was a circadian rhythm in the duration of life-span in mice bearing the EAC. A circadian rhythm in the incorporation of tritiated thymidine into DNA of the mouse spleen consistently was characterized by a peak during the nocturnal phase and a trough during the diurnal phase of the 12-hr light-12-hr dark cycle. In animals bearing an 8-day EAC, the rhythm in DNA synthesis in the spleen was phase-shifted, its wave form was changed, and the overall 24-hr mean was increased significantly. The phasing of the rhythm in EAC-bearing mice was not reproducible. This finding demonstrated that the presence of the EAC severely altered the natural rhythm in DNA synthesis in the spleen and resulted in a rhythmic pattern which was constantly changing. The presence of an 8-day EAC, however, had no effect on the amplitude, overall level, or the phasing of the circadian rhythm in the mitotic index in the cornea. A staggered light-dark cycle of 2 weeks duration did not completely phase-shift the DNA synthesis rhythm in the spleen but did completely phase-shift the rhythm in the mitotic index in the corneal epithelium. In mice subjected to a daily feeding period limited to 4 hr, the rhythm in DNA synthesis in the spleen, in both EAC-bearing and non-EAC bearing mice, was phase-shifted such that the peak occurred during the time of feeding and the trough occurred prior to the feeding period. The rhythm in the mitotic index in the cornea was not phase-shifted or altered in any way by the feeding schedule and thus remained fixed to the light-dark cycle. The DNA synthesis rhythm in the normal spleen demonstrated a phasing very similar to the circadian rhythm in the length of survival in mice challenged with EAC and the circadian rhythm in DNA synthesis in the normal thymus.     

Antitumour activity of saffron (Crocus sativus)

Antitumor activity of saffron (Crocus sativus) extract a commonly used spice in India was studied against intraperitoneally transplanted sarcoma-180 (S-180), Ehrlich ascites Carcinoma (EAC) and Dalton's lymphoma ascites (DLA) tumours in mice. Oral administration of 200 mg/kg body weight of the extract increased the life span of S-180, EAC, DLA tumour bearing mice to 111.0%, 83.5% and 112.5%, respectively. The same extract was found to be cytotoxic to P38B, S-180, EAC and DLA tumour cells in vitro. Thymidine uptake studies indicated the mechanism of action of the extract at the site of DNA synthesis. Toxicity studies showed that the hematological and biochemical parameters were within normal range. These results indicate the potential use of saffron as an anticancer agent.     

Antiproliferative effects of interferon-alphaCon1 on ovarian clear cell adenocarcinoma in vitro and in vivo.

PURPOSE: We examined the antiproliferative effect of IFN-alphaCon1 and its mechanism on ovarian clear cell adenocarcinoma in vitro and in vivo. EXPERIMENTAL DESIGN: (a) The effects of IFN-alphaCon1 on growth, morphology, cell cycle, and type I IFN-alpha receptor (IFNAR-2) expression were examined on two ovarian clear cell adenocarcinoma cell lines (KOC-5C and KOC-7C) in vitro. (b) KOC-5C or KOC-7C cells were transplanted into nude mice, and changes in tumor volume, tumor weight, apoptosis, necrosis, and microvessel density were investigated. The expression of angiogenesis factors was examined in the serum and the developed tumors. RESULTS: Both cell lines expressed IFNAR-2 mRNA, but its protein was detected only in KOC-7C. In KOC-7C cells, antiproliferative effects were observed in a time- and dose-dependent manner and cell division was blocked at the S phase. The KOC-7C tumors showed decreases in tumor volume and weight; a decreasing tendency in basic fibroblast growth factor (bFGF), vascular endothelial growth factor, and interleukin (IL)-8 protein expression in the tumor; a significant decrease in bFGF and IL-8 protein expression in the serum, and of microvessel density; and significant increase in apoptosis and necrosis in the tumor. In the KOC-5C tumors, these in vitro and in vivo changes were not apparent, and the antiproliferative effects of IFN-alphaCon1 were not obvious. CONCLUSIONS: IFN-alphaCon1 suppresses tumor proliferation by inducing apoptosis, blocking the cell cycle, and inhibiting tumor angiogenesis. Our findings show that the clinical efficacy of IFN-alphaCon1 can be predicted by examining IFNAR-2 expression on tumor cells, and the efficacy of IFN-alphaCon1 treatment can be evaluated by measuring serum bFGF and IL-8 levels.     

Growth retardation and prevention of Ehrlich solid tumor by Clostridium perfringens type A spores and culture supernatant.

When given by direct s.c. injection into the Ehrlich solid carcinoma 1 week after s.c. tumor transfer, viable crude spores of Clostridium perfringens type A (attenuated mutant strain LNG11 ATCC 29348) inhibited tumor growth and significantly prolonged the life span of male outbred Swiss mice. Under these conditions a concentrated sterile supernatant of a C. perfringens culture proved to be slightly more effective than were viable crude spores. In contrast viable crude spores were ineffective in the treatment of female Swiss mice, but the sterile supernatant retained significant activity. When given at the time and site of s.c. grafting of Ehrlich tumor cells, a concentrated sterile supernatant of a C. perfringens culture prevented tumor growth in 80% of male outbred Swiss mice. Under these conditions viable crude spores prevented tumor growth in 70% of mice and significantly prolonged the life span in the other 30%. When given by i.p. injection and before i.p. grafting of tumor cells, viable crude spores of C. perfringens prevented Ehrlich ascites tumor in 5 of 12 Swiss mice and prolonged life span in the other 7. In contrast concentrated sterile supernatant and viable purified spores were ineffective in the prevention or delay of the growth of Ehrlich ascites tumor. These data indicate that C. perfringens can be a potent antitumor agent without producing the harmful anaerobic infection of solid tumors (clostridial oncolysis.     

Treatment with Alstonia scholaris enhances radiosensitivity in vitro and in vivo

The radiosensitizing effect of 5 micrograms/mL of alkaloid fraction of Alstonia scholaris (ASERS) was evaluated in various neoplastic cell lines, namely: HeLa, HePG2, HL60, MCF-7, and KB exposed to 0, 0.5, 1, 2, 3, and 4 Gy of gamma-radiation. The irradiation of various cells caused a dose-dependent elevation in the cytotoxicity, and a maximum cytotoxic effect was observed at 4 Gy (the highest dose) in all the cell lines studied. The ASERS pretreatment increased the effect of radiation as evidenced by enhanced cell killing when compared with the concurrent phosphate-buffered saline (PBS) treated irradiation group. The greatest elevation in cell killing was observed for HeLa and KB cells, followed by HL60, MCF7, and HePG2 cells. The in vitro observations were confirmed by in vivo studies, where the Ehrlich ascites carcinoma (EAC) bearing mice were treated with 120 mg/kg body weight of ASERS before exposure to 0, 1, 2, 4, 6, and 8 Gy of hemibody (below the rib cage) gamma-radiation. Irradiation of EAC mice caused a dose-dependent tumor regression, as evidenced by increased life span of the animals. The pretreatment of tumor-bearing animals with 120 mg/kg ASERS resulted in a further remission in the tumor when compared with the concurrent nondrug-treated irradiated controls; as a result there was a radiation dose-dependent increase in the life span of tumor-bearing animals receiving 120 mg/kg ASERS, except for 8 Gy, where it was less than the concurrent control. The above findings corroborate with a time-dependent decrease in the glutathione (GSH) contents, accompanied by an increase in lipid peroxidation. Our study demonstrates that ASERS treatment enhances the effect of radiation and results in disease-free survival of the mice.     

Effect of tumor size on monoclonal antibody uptake in a metastatic model.

We studied the effect of tumor size on monoclonal antibody (mAb) in a murine hepatic model. Intrasplenic injection of HT-29 LMM metastatic human colon cancer cell line reproducibility results in hepatic metastases formation in congenitally athymic mice. HT-29-15, a murine mAb of the IgG1 class reactive with the HT-29 LMM cell line, and BL-3, an isotype-matched control mAb, were labeled with iodine 125. Labeled mAbs were injected intravenously into mice with hepatic metastases. Animals were sacrificed on day 5, and tumor and normal tissue weighed and counted. Specific mAb uptake (percent injected dose per gram, %ID/g) by hepatic metastases (5.16 +/- 3.96) was significantly greater than nonspecific uptake (1.41 +/- 0.42) (P less than 0.001). %ID/g of tumor was dependent upon the mAb used, and was independent of tumor weight; consequently, a linear correlation between tumor weight and total uptake (%ID) for specific mAb (r = 0.88, P less than 0.0001) and nonspecific mAb (r = 0.99, P less than 0.0001) administration was demonstrated. We have shown both specific and nonspecific mAb uptake per gram of tumor to be a constant for the given mAb/tumor system and with uptake of mAb to be linearly related to tumor weight.     

Differential effects of human natural interferon-alpha and mismatched double-stranded RNA against a human renal cell carcinoma xenograft

The antitumor effects of natural human IFN-alpha and mismatched dsRNA against the human renal cell carcinoma cell line 786-0 were studied both in a clonogenic soft agar assay and in the nude mouse. The 786-0 cells were sensitive in vitro to the antiproliferative effects of IFN-alpha in a dose-response manner, up to 3000 IRU/ml. These cells were also sensitive, in a dose-dependent manner, to mismatched dsRNA in the clonogenic assay. Mismatched dsRNA was effective in inhibiting tumor growth (p less than 0.001) in nude mouse xenografts, with regression of the tumor mass seen in all animals. A significant increase in survival (p less than 0.001) was seen in the mismatched dsRNA treated group. In contrast, IFN-alpha did not inhibit tumor growth in vivo, even though significant titers of IFN-alpha (greater than 3,000 IRU/ml) were found in the serum shortly after treatment. Mismatched dsRNA did not induce the production of human IFNs by the tumor cells in vitro. Assays of mouse IFN induction and their in vitro antigrowth effects indicated that the in vivo antiproliferative effect of mismatched dsRNA was probably not due to potentiation of any direct effects by the induced mouse IFNs. Tumor growth inhibition appeared to occur, at least in part, from the significant augmentation (p less than 0.01) of natural killer cell activity by mismatched dsRNA, as measured in the spleen cells of treated mice. These results suggest that, although both IFN-alpha and mismatched dsRNA can be directly antiproliferative against this tumor, either the IFN-independent antitumor effects of mismatched dsRNA or the mismatched dsRNA-induced augmentation of the host immune response plays a major role in tumor regression. Potentially, both mechanisms may be important in this system.     

Vaccination with viable human umbilical vein endothelial cells prevents metastatic tumors by attack on tumor vasculature with both cellular and humoral immunity.

PURPOSE: Because tumor endothelium is rarely targeted by immunity but is critically important for tumor growth, the immunity against tumor endothelium is to be developed as a novel antitumor strategy. EXPERIMENTAL DESIGN: First, viable human umbilical vein endothelial cells (HUVEC) were immunized to C57BL/6 and BALB/c mice to evoke specific CTLs as well as antibodies against tumor endothelium. Lewis lung carcinoma or myeloma cells were subsequently inoculated to evaluate the effect on tumor growth by vaccination. Second, the effect on tumor metastasis by vaccination was studied using tumor-resected mice receiving HUVEC immunization 3 days after excision. Third, the immune sera and T lymphocytes from HUVEC-immunized mice were transferred to tumor-bearing mice and added to cultured HUVECs to investigate their antiproliferative effect. RESULTS: Viable HUVEC immunization showed potent antitumor effects in Lewis lung carcinoma and myeloma tumor models. Both immune sera and CTL inhibited tumor growth and specifically suppressed proliferation of HUVECs. Particularly, tumors entirely disappeared on day 90 after tumor inoculation in four of six tumor-bearing mice receiving CTL therapy. In a metastatic tumor model, we found that the HUVEC vaccination prolonged life span from 30.9 to 41.5 days after tumor resection compared with PBS-treated mice without apparent side effects. CONCLUSIONS: Vaccination with viable HUVECs evoked both humoral and cellular immunity against tumor microvasculature, and therefore significantly inhibited tumor growth and prolonged life span of tumor-resected mice. This may provide with a novel treatment for metastatic tumors. Moreover, we have established a convenient method to evoke specific CTL against tumor angiogenesis.     

Silibinin protects against photocarcinogenesis via modulation of cell cycle regulators, mitogen-activated protein kinases, and Akt signaling

Here, we assessed the protective effect of silibinin on UVB-induced skin carcinogenesis in SKH-1 hairless mice. Topical application of silibinin before or immediately after UVB exposure or its dietary feeding resulted in a strong protection against photocarcinogenesis, in terms of tumor multiplicity (60-66%; P < 0.001), tumor volume per mouse (93-97%; P < 0.001) and tumor volume per tumor (80-91%; P < 0.001). Silibinin also moderately inhibited tumor incidence (5-15%; P < 0.01) and delayed tumor latency period (up to 4 weeks; P < 0.01-0.001). To investigate in vivo molecular mechanisms of silibinin efficacy, tumors and uninvolved skin from tumor-bearing mice were examined immunohistochemically for proliferation, p53, apoptosis, and activated caspase-3. Silibinin treatment showed a strong decrease (P < 0.001) in proliferating cell nuclear antigen-positive cells and an increase in p53-positive (P < 0.005-0.001), terminal deoxynucleotidyltransferase-mediated nick end labeling-positive (P < 0.005-0.001), and cleaved caspase-3-positive cells (P < 0.001). Western blot analysis of normal skin and tumor lysates showed that silibinin decreases the levels of cyclin-dependent kinase 2 and cyclin-dependent kinase 4 and associated cyclins A, E, and D1, together with an up-regulation of Cip1/p21, Kip1/p27, and p53. Silibinin also showed a strong phosphorylation of extracellular signal-regulated protein kinase 1/2, stress-activated protein kinase/c-JUN NH2-terminal kinase 1/2, and p38 mitogen-activated protein kinases but inhibited Akt phosphorylation and decreased survivin levels with an increase in cleaved caspase-3. Together, these results show a strong preventive efficacy of silibinin against photocarcinogenesis, which involves the inhibition of DNA synthesis, cell proliferation, and cell cycle progression and an induction of apoptosis. Furthermore, these results also identify in vivo molecular mechanisms of silibinin efficacy against photocarcinogenesis.