Effects of dietary supplementation of mannan-oligosaccharide on virus shedding in avian influenza (H9N2) challenged broilers

Avian influenza (AI) is a highly contagious disease causing significant economic losses worldwide. The aim of this study is to evaluate the effect of mannan-oligosaccharide (MOS) on tracheal and cloacal virus shedding in AI challenged broilers and contamination of environment with H₉N₂. A total of 300 1-day-old-broiler chicks were randomly divided into 3 groups (A, B and C) and supplemented 0.2, 0.5 and 0.0% MOS, respectively in NRC recommended diet for 36 days. On day 21 the groups were further split into two sub groups A+ve, A-ve, B+ve, B-ve, C+ve and C-ve with 5 replicates each. The positive groups were shifted to remote sheds and were challenged intranasally with 0.1 ml of reference virus (AIV; Pk-UDL/01/08 H₉N₂) with EID₅₀ = 10^-6.66. Treatment reduces (P<0.05) cloacal virus shedding from day 24 to 26 and 28 to 32. Tracheal virus shedding was lower (P<0.05) on days 25-26 and 28-30 in treatment groups. Day 27 showed highest (P>0.05) virus shedding in all groups. However the reduction of viral shedding is faster in treatment groups and showed no virus shedding on day 32. Maternal antibody titer against AI showed a declining pattern but MOS influenced (P<0.05) the titer in treated groups. Hence the use of MOS may constitute a novel and effective plausible alternative that reduces the spread of disease by decreasing virus shedding and contamination of environment from AIV (H₉N₂) infection in poultry.

Etanidazole as a modulator of combined modality therapy in the rat 9l-gliosarcoma

The use of chemotherapy has led to improved treatment outcome for some pediatric patients with medulloblastoma. We have used a pre-radiation chemotherapy regimen consisting of vincristine and CDDP. The 9L gliosarcoma implanted intracranially and subcutaneously in the same animals was used as a preclinical model system to assess the efficacy of treatment combinations including: vincristine, CDDP, cyclo-phosphamide, etanidazole and radiation. The experimental endpoints were percent increase-in-lifespan, tumor growth delay and tumor cell survival. Both the tumor growth delay and percent increase-in-lifespan improved as the number of agents included in the chemotherapy regimen increased. so that the chemotherapy regimen including all four agents (ETA/VIN/CDDP/CTX) resulted in the greatest tumor growth delay (23.6 +/- 1.5 days) and the greatest increase-in-lifespan (35.8%). When radiation (20 Gray, single dose) was added to the treatment regimens the combinations of ETA/CTX/X-ray and ETA/VIN/CDDP/CTX/X-ray resulted in equivalent tumor growth delays (25.2 +/- 1.3 days and 25.8 +/- 1.7 days, respectively), while the greatest increase-in-lifespan (39.1%) was obtained with the five agent combination. The response of the 9L gliosarcoma to CDDP and cyclophosphamide over a dosage range was very similar to that of the murine FSaII fibrosarcoma. Our results indicate that etanidazole may be an effective chemosensitizer of combination chemotherapy and combined modality treatment regimens for brain tumors.

Evidence of enzootic circulation of West Nile virus (Nea Santa-Greece-2010, lineage 2), Greece, May to July 2011

A West Nile virus (WNV) surveillance network including sentinel chickens was deployed in Thessaloniki county, Greece, from May to July 2011. For the first time in summer 2011, a chicken WNV isolate from 6 July was molecularly identified. The partial NS3 sequence was identical to that of the Nea Santa-Greece-2010 WNV lineage 2, detected in central Macedonia in 2010. This suggests that WNV is actively circulating in central Macedonia and that it may have overwintered in northern Greece.

Evidence of enzootic circulation of West Nile virus (Nea Santa-Greece-2010, lineage 2), Greece, May to July 2011

A West Nile virus (WNV) surveillance network including sentinel chickens was deployed in Thessaloniki county, Greece, from May to July 2011. For the first time in summer 2011, a chicken WNV isolate from 6 July was molecularly identified. The partial NS3 sequence was identical to that of the Nea Santa-Greece-2010 WNV lineage 2, detected in central Macedonia in 2010. This suggests that WNV is actively circulating in central Macedonia and that it may have overwintered in northern Greece.

Gene diversity for haptoglobin and transferrin classical markers among Hindu and Muslim populations of Aligarh City, India

The present paper reports the distribution of serum protein markers viz. haptoglobin and transferrin in two major groups of Aligarh city of North India. In present study we have undertaken a survey of 538 individuals belonging to eight different populations, four from the Hindu community i.e. Brahmin, Bania, Rajput and Jatav, and the rest four among the Muslim community i.e. Syed, Sheikh, Pathan and Ansari. The heterozygosity ranged from 0.2939 (Ansari) to 0.4873 (Brahmin) for haptoglobin and from 0.000 (Rajput) to 0.1498 (Pathan) for transferrin. The values of D(ST) are 0.4122 and 0.4406, and that of G(ST) are 0.5059 and 0.9726 for haptoglobin and transferrin markers respectively. Through F(ST) test, it has been concluded that there is a high genetic differentiation of populations within Hindu and Muslim groups, though there is absence of any significant differences between these groups.

Validation of the ALS assay in adult patients with culture confirmed pulmonary tuberculosis

Background

We have earlier shown that Bacille Calmette-Guérin (BCG) vaccine-specific IgG Antibodies in Lymphocyte Supernatant (ALS) can be used for diagnosis of active tuberculosis (TB) in adults and children.

Methodology/Principal Findings

The ALS method was validated in a larger cohort (n = 212) of patients with suspicion of pulmonary TB using multiple antigens (BCG, LAM, TB15.3, TB51A, CFP10-ESAT6-A, CFP, CW) from Mycobacterium tuberculosis. The sensitivity and specificity of the ALS assay was calculated using non-TB patients as controls. The sensitivity and the specificity were highest with BCG vaccine (90% and 88% respectively) followed by LAM (89% and 87% respectively). Simultaneous assessment of multiple antigen-specific antibodies increased sensitivity (91%) and specificity (88%). Using higher lymphocyte count in smaller volume of culture media increased detection and reduced the assay duration to ∼30 hrs. Twenty one patients with clinical findings strongly suggestive of TB finally diagnosed as non-TB patients were positive by the ALS assay, of which 9 (43%) were positive for 7 antigens and 19 (90%) for at least 3 antigens.

Conclusions/Significance

Our findings show that simultaneous detection of antigens improves the diagnostic potential of the ALS assay; the modified method increases sensitivity and can provide results in <48 hours, and enable detection of some cases of pulmonary TB that are not detectable by standard methods.

Impact of zinc supplementation on subsequent morbidity and growth in Bangladeshi children with persistent diarrhoea

This study was conducted to explore whether supplementation of zinc to children during persistent diarrhoea has any subsequent effect on morbidity and growth. A prospective follow-up study was conducted among children, aged 3-24 months, with persistent diarrhoea, who participated earlier in a double-blind randomized placebo-controlled trial. During persistent diarrhoea, children were randomly allocated to receive either zinc in multivitamin syrup or only multivitamin syrup for two weeks. After recovering from diarrhoea, 76 children in the multi-vitamin syrup and 78 children in the zinc plus multivitamin syrup group were followed up for subsequent morbidity and growth. Weekly morbidity and two-weekly anthropometric data were collected for the subsequent 12 weeks. Data showed that episodes and duration of diarrhoea were reduced by 38% and 44% respectively with supplementation of zinc. There was no significant difference in the incidence or duration of respiratory tract infection between the zinc-supplemented and the non-supplemented group. Improved linear growth was observed in underweight children (weight-for-age <70% of the National Center for Health Statistics standard) who received zinc compared to those who did not receive.

Low birth weight is associated with altered immune function in rural Bangladeshi children: a birth cohort study

BACKGROUND

Low birth weight is generally an outcome of a fetal insult or nutritional insufficiency. Recent studies have shown that such exposure early in life may have long-term implications for later immunocompetence and susceptibility to infectious diseases.

OBJECTIVE

We aimed to investigate the effect of birth weight on immune function in preschool-age children.

DESIGN

A birth cohort cross-sectional study was conducted in children (n = 132) aged 60.8 +/- 0.32 mo who were born in Matlab, a rural area of Bangladesh, and whose weight and length were measured within 72 h of birth. The outcome measures were thymopoiesis, T cell turnover, acute phase response, and percentage of lymphocytes.

RESULTS

Children born with low birth weight (<2500 g; LBW group, n = 66) had significantly higher concentrations of T cell receptor excision circles in peripheral blood mononuclear cells-a biomarker for thymopoiesis-and significantly higher serum bactericidal activity and C-reactive protein concentrations than did children born with normal birth weight (>or=2500 g; NBW group, n = 66) (P < 0.05 for both). The LBW group children had significantly lower concentrations of interleukin 7 in plasma (P = 0.02), shorter telomere length in peripheral blood mononuclear cells (P = 0.02), and a lower percentage of CD3 T cells (P = 0.06) than did the NBW group children.

CONCLUSIONS

Greater peripheral T cell turnover (shorter telomeres and lower CD3 concentrations) due to immune activation (elevated C-reactive protein concentrations and bactericidal activity) may have resulted in a greater need for replenishment from the thymus (higher T cell receptor excision circles); these events may cause lower immune functional reserve in preschool-age children born with LBW. Thus, LBW has implications for immunocompetence and increased vulnerability to infectious diseases in later life.

Improved outcome in shigellosis associated with butyrate induction of an endogenous peptide antibiotic

Shigella is a major cause of morbidity, mortality, and growth retardation for children in developing countries. Emergence of antibiotic resistance among Shigellae demands the development of effective medicines. Previous studies found that the endogenous antimicrobial peptide LL-37 is down-regulated in the rectal epithelium of patients during shigellosis and that butyrate up-regulates the expression of LL-37 in colonic epithelial cells in vitro and decreases severity of inflammation in experimental shigellosis. In this study, Shigella-infected dysenteric rabbits were treated with butyrate (0.14 mmol/kg of body weight) twice daily for 3 days, and the expression levels of the rabbit homologue to LL-37, CAP-18, were monitored in the colon. Butyrate treatment resulted in (i) reduced clinical illness, severity of inflammation in the colon, and bacterial load in the stool, (ii) significant up-regulation of CAP-18 in the surface epithelium, and (iii) disappearance of CAP-18-positive cells in lamina propria. The active CAP-18 peptide was released in stool from its proform by butyrate treatment. In healthy controls, CAP-18 expression was localized predominantly to the epithelial surface of the colon. In infected rabbits, CAP-18 expression was localized to immune and inflammatory cells in the colon, whereas the ulcerated epithelium was devoid of CAP-18 expression. The combination of CAP-18 and butyrate was more efficient in killing Shigella in vitro than CAP-18 alone. Our findings indicate that oral butyrate treatment in shigellosis may be of clinical value because of induction of the endogenous cathelicidin CAP-18 in the colonic epithelium, stimulation of the release of the active peptide CAP-18, and promoting elimination of Shigella.

Risk factors for mortality due to shigellosis: a case-control study among severely-malnourished children in Bangladesh

To determine the risk factors for death of severely-malnourished Bangladeshi children with shigellosis, a case-control study was conducted at the Clinical Research and Service Centre of ICDDR,B: Centre for Health and Population Research in Dhaka, Bangladesh. One hundred severely-malnourished children (weight-for-age <60% of median of the National Center for Health Statistics), with a positive stool culture for Shigella dysenteriae type 1 or S. flexneri, who died during hospitalization, were compared with another 100 similar children (weight-for-age <60% and with S. dysenteriae type 1 or S. flexneri-associated infection) discharged alive. Children aged less than four years were admitted during December 1993-January 1999. The median age of the cases who died or recovered was 9 months and 12 months respectively. Bronchopneumonia, abdominal distension, absent or sluggish bowel sound, clinical anaemia, altered consciousness, hypothermia, clinical sepsis, low or imperceptible pulse, dehydration, hypoglycaemia, high creatinine, and hyperkalaemia were all significantly more frequent in cases than in controls. In multivariate regression analysis, altered consciousness (odds ratio [OR]=2.6, 95% confidence interval [CI] 1.0-6.8), hypoglycaemia (blood glucose <3 mmol/L (OR=7.8, 95% CI 2.9-19.6), hypothermia (temperature <36 degrees C) (OR=5.7, 95% CI 1.5-22.1), and bronchopneumonia (OR=2.5, 95% CI 1.1-5.5) were identified as significant risk factors for mortality. Severely-malnourished children with shigellosis having hypoglycaemia, hypothermia, altered consciousness and/or bronchopneumonia were at high risk of death. Based on the findings, the study recommends that early diagnosis of shigellosis in severely-malnourished children and assertive therapy for proper management to prevent development of hypothermia, hypoglycaemia, bronchopneumonia, or altered consciousness and its immediate treatment are likely to reduce Shigella-related mortality in severely-malnourished children.

Use of antibodies in lymphocyte secretions for detection of subclinical tuberculosis infection in asymptomatic contacts

We have previously demonstrated that Mycobacterium bovis BCG-specific immunoglobulin G antibodies in lymphocyte secretions (ALS) can be employed as a marker for active tuberculosis (TB). We aimed to determine whether the ALS method allows detection of subclinical TB infection in asymptomatic individuals. A prospective study of family contacts (FCs) of patients with active TB and healthy controls was performed. Thirteen of 42 FCs had high ALS responses, including 6 FCs who subsequently developed active TB. No correlation was observed between the tuberculin skin test and the ALS responses in the FCs (r = 0.1, P = 0.23). Among patients with active TB, BCG-specific ALS responses steadily declined from the time of diagnosis through 6 months following antimycobacterial chemotherapy (P = 0.001). The ALS assay enabled detection of infection in exposed symptom-free contacts, who are at greater risk for developing active TB. The method may also allow discrimination between effective treatment of active infection and suboptimal response to therapy.

Risk of hepatitis A infection following travel

Travel to endemic areas is one of the most frequently reported risk factors for infection with the hepatitis A virus (HAV). We evaluated the association between HAV infection and travel, by area of destination. We conducted a case-control study on all cases of HAV infection reported to the Italian National Surveillance System for Acute Viral Hepatitis in the period 1996-2000. The study population consisted of 9695 persons with HAV infection (cases) and 2590 with HBV infection (controls). The risk of acquiring HAV was highest for travel to Asia, Africa and Latin America [Odds Ratio = 9.30 (95%CI = 6.71-12.9)]; a three-fold statistically significant excess of risk was found for travel to southern Italy (OR = 3.03) and to the Mediterranean Area and Eastern Europe (OR = 3.15). Travel was implicated in 28% of the cases of HAV infection. When stratifying the analysis by area of residence (northern and central Italy vs southern Italy and the Islands), the above-mentioned risks were confirmed only for those residing in northern and central Italy, with no significant risk for those residing in southern Italy and the Islands. Travel to areas endemic for HAV infection constitutes a considerable risk. Our results highlight the importance of developing health policies for improving environmental and hygienic conditions, as well as the prevention of certain eating habits. Vaccination before travelling to a medium or high endemic area could be a safe and effective means of preventing travel-related HAV infection.

Cyclooxygenase inhibitors are potent sensitizers of prostate tumours to hyperthermia and radiation

It has previously been demonstrated that hyperthermia can activate prostaglandin synthesis and that prostaglandins are protective against hyperthermia. This study examined the use of inhibitors of prostaglandin synthesis on the response of prostate tumours to hyperthermia. The non-steroidal anti-inflammatory drugs (NSAID) ibuprofen and sulindac, known cyclooxygenase inhibitors that inhibit prostaglandin production, were effective hyperthermia sensitizers and augmented growth delay of DU-145 and PC-3 prostate tumours to combined radiation and hyperthermia treatment protocols. Pre-treatment of mice with ibuprofen and sulindac at hyperthermia sensitizing doses resulted in significant (p < 0.01) inhibition of hyperthemia-induced serum prostaglandin E2. These findings indicate that NSAID may have both sensitizing effects on prostate tumour growth and may function by inhibiting prostaglandin synthesis.

Effects of the flavonoid drug quercetin on the response of human prostate tumours to hyperthermia in vitro and in vivo

Tumour hyperthermia, although potentially a powerful therapeutic agent and radiation sensitizer, is hindered by a number of considerations including inhomogeneous heating of deep seated tumours due to energy deposition and perfusion issues. One solution is to design hyperthermia sensitizers to amplify the effects of hyperthermia, particularly at cold spots within the tumour undergoing treatment. This study examined the use of Quercetin, a flavonoid drug shown previously to antagonize the expression of HSP72 and induce apoptosis as a sensitizer of prostate cancer growth in vivo. Quercetin dose-dependently suppressed PC-3 tumour growth in vitro and in vivo. When combined in a treatment protocol with hyperthermia, quercetin drastically inhibited tumour growth and potently amplified the effects of hyperthermia on two prostate tumour types, PC-3 and DU-145 in vivo. These experiments, thus, suggest the use of Quercetin as a hyperthermia sensitizer in the treatment of prostate carcinoma.

Double high-dose chemotherapy with stem cell rescue (HD-SCR) in patients with breast cancer - effect of sequence

INTRODUCTION

A preliminary analysis of our double high-dose chemotherapy with stem cell rescue (HD-SCR) clinical trial for breast cancer, and preclinical cross-resistant studies, suggested that melphalan (M) adversely affected response to subsequent chemotherapy, i.e., that the sequence of alkylating agents (AAs) might affect response. We, therefore, constructed and examined preclinical models to determine whether prior exposure to M, in fact, adversely affected response to other therapy.

PURPOSE

The purpose of the study was to determine whether the sequence of AAs, specifically the prior use of M, adversely affected response to subsequent treatment.

METHODS

The methods employed were the following: (1) Human tumor cell lines rendered resistant by in vitro sequential exposure to five different AAs were developed. The resistant cell lines were examined for cross-resistance to alkylating and other agents. (2) In vivo studies in the p388 mouse leukemia for resistance and cross-resistance among the AAs. (3) In vivo studies of the effect of sequence of AAs on response in mice bearing EMT6 breast cancer. (4) The double transplant model was developed in the mouse and the sequence of high-dose AAs was studied. (5) Biochemical and reverse transcriptase-polymerase chain reaction (RT-PCR) studies of the various resistant tumor cell lines.

RESULTS

(1) The in vitro human tumor cells resistant to M were cross-resistant in 57% of tests to other AAs. In contrast, resistance for other AAs crossed to other agents in only 10 to 20% of tests. (2) The in vivo studies of p388 indicated that resistance to M commonly crossed to other AAs and many non-AAs. (3) The results for the mouse breast cancer (EMT6) studies of the sequence of AAs again indicated that M employed first markedly reduced responsiveness to subsequent treatment, particularly with AAs. (4) The double transplant model: again, M first markedly reduced response to other agents. (5) The in vitro resistant human tumor cell lines, particularly the breast cancer cell line MCF7, were found to contain high concentrations of glutathione S1 transferase gamma, which is consistent with that mechanism being responsible for resistance.

CONCLUSION

The sequence of alkylating agent treatment may substantially influence response. Melphalan, particularly, produces resistance that commonly crosses to the other AAs. Mechanistic studies indicate significant changes in glutathione S1 transferase, a known mechanism for broadly based resistance to AAs.

Enzymatic rationale and preclinical support for a potent protein kinase C beta inhibitor in cancer therapy

The macrocyclic bisindolylmaleimide, LY333531, selectively inhibits protein kinase C beta 1 and beta 2 isoforms with an approximate IC50 of 5 nanomolar. The efficacy of LY333531 administered alone and in combination with cytotoxic cancer therapies in models of non-small cell lung carcinoma and brain tumors was determined in vivo. In the Lewis lung carcinoma, administration of LY333531 enhanced the activity of paclitaxel and fractionated radiation and, to a lesser degree, carboplatin and gemcitabine. In the human T98G glioblastoma multiforme xenograft, the addition of LY333531 to treatment with carmustine (BCNU) resulted in enhanced tumor response in a nodule grown subcutaneously and increased life-span in animals bearing an intracranial tumor from 37 days in the control animals to 64 days in the BCNU treated animals, and to 104 days in the LY333531 plus BCNU treated animals with 4 out of 5 animals being long-term survivors.

The proteasome inhibitor PS-341 in cancer therapy

The anticancer activity of the boronic acid dipeptide proteasome inhibitor PS-341 was examined in vitro and in vivo. PS-341 was a potent cytotoxic agent toward MCF-7 human breast carcinoma cells in culture, producing an IC90 of 0.05 microM on 24 h of exposure to the drug. In the EMT-6 tumor cell survival assay, PS-341 was equally cytotoxic administered p.o. or by i.p. injection up to a dose of 2 mg/kg. PS-341 was also toxic to the bone marrow colony-forming unit-granulocyte macrophage. PS-341 increased the tumor cell killing of radiation therapy, cyclophosphamide, and cisplatin in the EMT-6/Parent tumor, but was not able to overcome the in vivo resistance of the EMT-6/CTX and EMT-6/CDDP tumors. In the tumor growth delay assay, PS-341 administered p.o. had antitumor activity against the Lewis lung carcinoma, both primary and metastatic disease. In combination, regimens with 5-fluorouracil, cisplatin, Taxol and adriamycin, PS-341 seemed to produce primarily additive tumor growth delays against the s.c. tumor and was highly effective against disease metastatic to the lungs. The proteasome is an interesting new target for cancer therapy, and the proteasome inhibitor PS-341 warrants continued investigation in cancer therapy.

Jasplakinolide: interaction with radiation and hyperthermia in human prostate carcinoma and Lewis lung carcinoma

PURPOSE

Jasplakinolide is a novel natural product anticancer agent which acts by inducing overpolymerization of actin. The aim of the current study was to explore the activity of jasplakinolide with hyperthermia and radiation.

METHODS

The response of human PC-3 and DU-145 prostate carcinoma cells and DU-145 xenografts and the response of the Lewis lung carcinoma to jasplakinolide were studied.

RESULTS

Jasplakinolide was cytotoxic toward human prostate carcinoma cells, DU-145, PC-3 and LNCaP in culture, killing 1 log of cells with 0.8, 0.3 and 0.07 microM of drug in 24 h, respectively. The combination of jasplakinolide and hyperthermia resulted in primarily additive cell killing by the two modalities in the three prostate carcinoma lines. In combination with radiation, jasplakinolide produced some diminution in the shoulder of the survival curve of normally oxygenated PC-3 cells and was a radiation sensitizer of hypoxic DU-145 cells and hypoxic PC-3 cells. In vivo, jasplakinolide was an active antitumor agent against the Lewis lung carcinoma and the DU-145 prostate carcinoma xenograft. Jasplakinolide was a radiation sensitizer in the Lewis lung carcinoma. Jasplakinolide was also effective against the systemic Lewis lung carcinoma, decreasing lung metastases. Lung metastases were further decreased when jasplakinolide was administered along with radiation to the subcutaneous primary tumor. In the DU-145 tumor, the effects of jasplakinolide and fractionated radiation for 1 or 2 weeks appeared to be primarily additive.

CONCLUSION

Jasplakinolide is an interesting new anticancer agent for which further study both as an anticancer agent and in combined modality regimens is warranted.

Sequence effect of irinotecan (CPT-11) and topoisomerase II inhibitors in vivo

The DNA topoisomerases I and II are the target of several clinically important antineoplastic agents which produce DNA cleavage by stabilization of the covalent DNA-protein bond with resultant cell death after DNA synthesis is attempted. Depletion of the target topoisomerase and reciprocal changes in the other occur with drug treatment.

PURPOSE AND METHODS

To develop empiric treatment regimens of combinations and sequences of agents directed against topoisomerase I (irinotecan/CPT-11) and II (etoposide and doxorubicin), in vivo studies were performed in mice bearing the EMT-6 mammary tumor to assess efficacy, host tolerance and the resultant biochemical changes in topoisomerase mRNA and protein.

RESULTS

At 24 h after therapy, depletion of the target topoisomerase mRNA and protein with reciprocal increases in the alternate topoisomerase mRNA and, to a lesser extent, protein were noted. No therapeutic antagonism was found with any combination or sequence of agents, and therapeutic antagonism was noted with concurrent irinotecan/etoposide and sequential doxorubicin/irinotecan. Depletion of target topoisomerases by combined therapy beyond a threshold necessary for therapeutic efficacy produced no additional benefit.

CONCLUSIONS

Antineoplastic therapy with combinations of topoisomerase I and II agents is feasible and may produce therapeutic synergy. The appropriate sequence may depend on the particular agents used. The rationale for such therapy, that topoisomerases I and II may have reciprocal and compensatory interactions, is supported by the biochemical data.

Interaction of tomudex with radiation in vitro and in vivo

The potential of the thymidylate synthase inhibitor, Tomudex to interact with ionizing radiation was assessed in vitro and in vivo in comparison with 5-fluorouracil. A concentration of 1 microM Tomudex decreased the shoulder of the radiation survival curves for normally oxygenated and hypoxic human HT-29 colon carcinoma cells and human SCC-25 head and neck squamous carcinoma cells, resulting in enhancement ratios of 10 and 2.8 for normally oxygenated and hypoxic HT-29 cells at 5 Gray, respectively, and enhancement ratios of 19.5 and 2.7 for normally oxygenated and hypoxic SCC-25 cell at 5 Gray, respectively. Two schedules of Tomudex administered to animals bearing the Lewis lung carcinoma resulted in additive tumor growth delay with the fractionated radiation therapy. In nude mice bearing the HT-29 colon carcinoma grown as a xenograft, administration of Tomudex daily for 5 days on a 1 or 2-week schedule resulted in increased tumor growth delay along with fractionated radiation therapy on the same schedules. However, administration of Tomudex intermittently on a 2-week schedule appeared to be more interactive with daily fractionated radiation therapy on the 2-week schedule. In each assay, the results obtained with Tomudex were equal to or exceeded those obtained with 5-fluorouracil. These findings indicate that clinical trial of Tomudex along with fractionated radiation therapy is warranted.

Potential of the aminosterol, squalamine in combination therapy in the rat 13,762 mammary carcinoma and the murine Lewis lung carcinoma

Squalamine, a naturally-occurring aminosterol, has demonstrated antiangiogenic activity in several experimental models. Extended treatment with other antiangiogenic agents has been shown to increase tumor oxygenation. Tumor oxygenation was measured using an Eppendorf pO2 histograph polarographic pO2 electrode system in the rat 13,762 mammary carcinoma after treatment of the tumor-bearing animals with squalamine (40 mglkg) on days 4 through 18 post tumor implantation. Under air breathing conditions, the hypoxic fraction (percent of pO2 readings < 5 mmHg) was 53% in controls and was decreased to 38% in the squalamine treated animals. While squalamine administration alone produced only a modest effect on the growth of the 13,762 tumor, there were increases in tumor growth delay of 1.9- to 2.5-fold when squalamine was administered along with cyclophosphamide, cisplatin and paclitaxel compared with the tumor growth delays observed with the chemotherapeutic agents alone. To determine the efficacy of squalamine alone and along with cytotoxic therapies against a model of primary and systemic disease, squalamine was administered to animals bearing the Lewis lung carcinoma by daily subcutaneous injection or by continuous infusion on days 4 through 18 post tumor implantation. Squalamine as a single agent had only a modest effect on the growth of the primary Lewis lung tumor but increased the tumor growth delays produced by cyclophosphamide, cisplatin, paclitaxel and 5-fluorouracil by 2.4- to 3.8-fold compared with the anticancer drugs alone. Squalamine administration alone substantially decreased the number of lung metastases found in animals bearing the Lewis lung carcinoma and further decreased the number of lung metastases when administered along with the chemotherapeutic agents.

Allosteric effectors of hemoglobin as modulators of chemotherapy and radiation therapy in vitro and in vivo

INTRODUCTION

A series of molecules designed to be allosteric effectors of hemoglobin were examined for their potential as radiation sensitizers in vitro and in vivo and for their potential as chemosensitizers in vivo as well as for their antimetastatic effect.

RESULTS

At a concentration of 100 microM for 1 h prior to, during and for 1.5 h after radiation exposure, the allosteric effectors decreased the shoulder of the radiation survival curve of normally oxygenated EMT-6 cells and increased the slope of the radiation survival curves of hypoxic EMT-6 cells resulting in dose-modifying factors of 1.8 to 2.1. In vivo the allosteric effectors had antitumor activity against the Lewis lung carcinoma and produced primarily additive tumor growth delay when administered along with fractionated radiation therapy. When administered on days 4 through 18 after tumor implantation, the allosteric effectors, especially JP-7, RSR-13 and RSR-4, were highly effective antimetastatic agents in animals bearing Lewis lung carcinoma. In cell culture, simultaneous exposure to the allosteric effectors (at 100 microM) effectively sensitized EMT-6 cells to the effects of 4-hydroperoxycyclophosphamide, thiotepa and carboplatin. The allosteric effectors were not very cytotoxic toward EMT-6 tumor cells from tumors treated in vivo with single doses of each molecule nor were these agents very cytotoxic toward bone marrow CFU-GM taken from the same animals.

CONCLUSIONS

It is likely that the allosteric effectors have a molecular target in addition to hemoglobin. Other possible targets include hydroxymethyl-glutaryl-CoA reductase or microsomal cytochrome b5.

Optimal scheduling of interleukin-12 and fractionated radiation therapy in the murine Lewis lung carcinoma

Interleukin-12 (IL-12), a naturally occurring cytokine, has demonstrated antitumor activity in several murine solid tumors. The Lewis lung carcinoma was used to study the most effective scheduling of recombinant murine interleukin-12 (rmIL-12) administration with fractionated radiation therapy. The effect of the schedule of rmIL-12 administration alone or along with a 1- or 2-week fractionated radiation therapy regimen was examined. Beginning rmIL-12 prior to or at the same time as radiation therapy and extending rmIL-12 through the radiation regimen and beyond produced the longest tumor growth delays. Those treatment regimens which were most effective against the primary tumor were also most effective in decreasing the number of lung metastases on day 20. To further assess the immunotherapeutic effects from rmIL-12 administration, the efficacy of rmIL-12 with fractionated radiation therapy delivered to a right hind-limb tumor was measured as tumor growth delay in an unirradiated left hind-limb tumor. There was some difference in the tumor growth delay between the unirradiated tumor in the animals bearing an irradiated tumor in the contralateral leg, and the tumors in animals receiving rmIL-12 only. Recombinant murine granulocyte-macrophage-colony stimulating factor (rmGM-CSF) was also an antitumor agent active against the Lewis lung carcinoma and produced an additive effect in combination with fractionated radiation therapy in this tumor. rmIL-12 was a radiation sensitizer in the Lewis lung carcinoma. When rmIL-12 (45-microg/kg) and rmGM-CSF (45 microg/kg) were administered together with fractionated radiation therapy, a marked increase in tumor growth delay resulted. This treatment combination also nearly ablated lung metastases on day 20 in these animals. These results may serve as a useful guide in developing clinical protocols, including rmIL-12 and fractionated radiation therapy.

Antitumor activity of creatine analogs produced by alterations in pancreatic hormones and glucose metabolism

When rats bearing the 13,762 mammary carcinoma were treated with intravenously administered creatine analogs, cyclocreatine, beta-guanidinopropionic acid or creatine phosphate on days 4 through 8 and 14 through 18 post tumor implantation, the tumor growth delay produced varied with whether the animals were drinking water or sugar water over the course of the study. The tumor growth delays increased when the animals drank sugar water from 9.3, 1.6 and 7.6 days for cyclocreatine, beta-guanidinopropionic acid and creatine phosphate, respectively, to 15.0, 6.3 and 12.6 days. Blood glucose was decreased over the course of the creatine analog treatment regimen and the skeletal muscle transport protein GLUT-4 increased 1.5 to 2-fold with the creatine analog treatments. Plasma insulin was profoundly decreased to 20-25% of normal by the creatine analog treatment while plasma glucagon levels were increased. Plasma somatostatin increased 3- to 4-fold during the administration of the creatine analogs. These results implicate alterations in pancreatic hormone balance in the antitumor activity of these creatine analogs.

Acute in vivo resistance in high-dose therapy

In the design of sequential high-dose chemotherapy regimens, the selection of antitumor alkylating agents to be included in each intensification and the interval between the intensifications are critical to the design of the therapy. The tumor cell survival assay and tumor growth delay assay using the murine EMT-6 mammary carcinoma were used as a solid tumor model in which to address these issues. Tumor-bearing mice were treated with high-dose melphalan or cyclophosphamide followed 7 or 12 days later by melphalan, cyclophosphamide, thiotepa, or carboplatin. After treatment with melphalan both 7 and 12 days later, the tumor was resistant to each of the four drugs studied. After treatment with cyclophosphamide both 7 and 12 days later, the tumor was resistant to melphalan and thiotepa but was not resistant to cyclophosphamide or carboplatin. To extend the interval between high-dose treatments to 14 and 21 days, after the first intensification the tumor was transferred to second hosts that were either drug-treated or not drug treated. When high-dose melphalan-treated tumors were treated with a second high dose of melphalan, the tumors were very resistant with the 14-day interval and less resistant with the 21-day interval. This small effect was evident in the bone marrow colony-forming unit, granulocyte-macrophage (CFU-GM), except in the hosts pretreated with melphalan. When high-dose cyclophosphamide-treated tumors were treated with a second high dose of cyclophosphamide, drug resistance was observed both with the 14-day and 21-day interval if the host was non-pretreated or was pretreated with melphalan, but not if the host was pretreated with cyclophosphamide. The same was true in the bone marrow CFU-GM. Tumor growth delay studies supported these findings in that treatment with high-dose cyclophosphamide, melphalan, thiotepa, and carboplatin resulted in less than additive tumor growth delay, whereas treatment with high-dose cyclophosphamide prior to treatment with high-dose melphalan, cyclophosphamide, thiotepa, or carboplatin resulted in additivity to greater-than-additive tumor growth delay. High-dose combination regimens required dose reduction of the drugs, which resulted in decreased tumor growth delays.

Transforming growth factor-beta 1 overexpression produces drug resistance in vivo: reversal by decorin

The gene for transforming growth factor-beta 1 (TGF-beta 1) was transfected into the murine EMT-6/Parent mammary carcinoma tumor line to form the EMT6/PRK5 beta 1E tumor line. In monolayer culture the EMT-6/PRK5 beta 1E tumor line secretes about 15-times as much TGF-beta 1 into the medium as the EMT-6/Parent line. There was no difference in the response of these two cell lines to 4-hydroperoxycyclophosphamide, cisplatin, melphalan or thiotepa in monolayer culture. When the EMT-6/PRK5 beta 1E cells were grown as a solid tumor in Balb/C mice, plasma levels of TGF-beta 1 were about 5-fold higher than in animals bearing the EMT-6/Parent tumor. The EMT-6/PRK5 beta 1E tumor was markedly resistant to a dosage range of cyclophosphamide, cisplatin, melphalan and thiotepa compared with the EMT-6/Parent tumor. The bone marrow CFU-GM from the animals bearing the EMT-6/PRK5 beta 1E tumor were spared from the cytotoxicity of the drugs compared with the bone marrow CFU-GM from animals bearing the EMT-6/Parent tumor. Administration of decorin, a naturally occurring inhibitor of TGF-beta 1, to animals bearing the EMT-6/PRK5 beta 1E tumor prior to treatment of the animals with the antitumor alkylating agents restored drug sensitivity to the tumor and to the bone marrow CFU-GM. Administration of decorin prior to the antitumor alkylating agents produced very little or no increase in the response of the EMT6/Parent tumor or the bone marrow CFU-GM from those animals. The EMT6/PRK5 beta 1E tumor model allows the effect of secretion of TGF-beta 1 on therapeutic resistance to be assessed directly compared with the EMT-6/Parent tumor. In vivo resistance occurred in the presence of high levels of TGF-beta 1 and was reversed by the TGF-beta 1 inhibitor decorin.

Prostate carcinoma response to cytotoxic therapy: in vivo resistance

Androgen independent prostate cancer is recognized as a chemotherapy resistant disease. Human prostate carcinoma DU-145, LNCaP and PC-3 cells in monolayer in exponential growth were exposed to various concentrations of melphalan, 4-hydroperoxycyclophosphamide or adriamycin for 1 hour. These cells were all responsive to the drugs, with DU-145 cells being the least sensitive and PC-3 cells the most sensitive. When the three human prostate carcinoma cell lines were grown as xenografts in nude or SCID mice and the animals treated with single doses of melphalan, cyclophosphamide or adriamycin, the tumors were not very responsive to the drugs. The DU-145 tumors were highly resistant to each drug. The PC-3 tumors were more sensitive; however, even the PC-3 tumors were less drug responsive than several murine tumors. All three prostate cell lines secreted transforming growth factor-beta (TGF-beta) into the cell culture medium, and when grown as xenograft tumors increased the plasma levels of TGF-beta in the animals. DU-145 cells produced the most TGF-beta and LNCaP cells produced the least. After administration of single doses of each of the chemotherapeutic agents to animals bearing the prostate carcinoma xenografts, there was a time dependent increase in plasma TGF-beta that was greatest in animals bearing the DU-145 tumor and least in animals bearing the LNCaP tumor. Immunohistochemical staining, showed that PC-3 tumors tended to have the most intense staining for TGF-beta and LNCaP tumors the least. In situ hybridization for TGF-beta mRNA showed an increase in TGF-beta mRNA that was time independent after chemotherapy administration in all three tumors. These results support the hypothesis that the drug resistance of prostate carcinoma is manifest in vivo, and that in vivo high levels of TGF-beta may protect these tumors from cytotoxic cancer therapies.

Optimal scheduling of interleukin 12 and chemotherapy in the murine MB-49 bladder carcinoma and B16 melanoma

The antitumor activity of interleukin (IL)-12, a naturally occurring cytokine, has been demonstrated in several murine solid tumors. Animals bearing established B16 melanoma or MB-49 bladder carcinoma were used to study the most effective scheduling of recombinant murine IL-12 (rmIL-12), along with systemic chemotherapy. rmIL-12 (0. 45, 4.5, or 45 microgram/kg) was more effective as a single agent when administered to mice bearing the MB-49 bladder carcinoma at the highest dose for 11 doses rather than for 5 doses. In combination with chemotherapy (Adriamycin, cyclophosphamide, or 5-fluorouracil), rmIL-12 administration did not increase the toxicity of the chemotherapy, and there was increased antitumor activity with each rmIL-12-drug combination. Administering rmIL-12 (45 microgram/kg) on days 4-14, along with Adriamycin, cyclophosphamide, or 5-fluorouracil on days 7-11, resulted in 2.2-2.7-fold increases in tumor growth delay, compared with the chemotherapy alone against the primary tumor, and a marked decrease in the number of lung metastases on day 20. Because the B16 melanoma grows more slowly than the MB-49 bladder carcinoma, allowing multiple courses of chemotherapy, cyclophosphamide could be administered. The rmIL-12 (45 microgram/kg)-cyclophosphamide combination regimen that was most effective overlapped 2 days with the terminal portion of the chemotherapy treatment. There was a parallel increase in the response of the primary tumor and metastatic disease to the lungs. Administration of rmIL-12 to animals bearing the MB-49 bladder carcinoma or the B16 melanoma was compatible with coadministration of chemotherapy at full dose without additional toxicity.

PEG-hemoglobin: effects on tumor oxygenation and response to chemotherapy

BACKGROUND

The study was undertaken to determine whether administration of PEG-hemoglobin could improve the oxygenation of a solid tumor prior to and after chemotherapy and to determine whether administration of PEG-hemoglobin could enhance the efficacy of chemotherapy in a solid tumor.

MATERIALS AND METHODS

Rats bearing the 13762 mammary carcinoma were untreated or treated with cyclophosphamide, melphalan, taxol or cisplatin. Tumor oxygenation was determined 24 hrs. after chemotherapy with or without administration of PEG-hemoglobin while the animals breathed air, 28% oxygen or carbogen. Mice bearing the EMT-6 murine mammary carcinoma were treated with single doses of chemotherapy with or without co-administration of PEG-hemoglobin and tumor cell and bone marrow CFU-GM survivals were determined. Other EMT-6 tumor-bearing mice were treated with multiple doses of chemotherapy with or without PEG-hemoglobin and tumor growth delay was determined.

RESULTS

Administration of PEG-hemoglobin was effective in decreasing hypoxia in the 13762 mammary carcinoma both prior to and after chemotherapy administration. Increasing the level of inspired oxygen further decreased the tumor hypoxia most effectively when the level of tumor cell killing by the chemotherapy was high. Administration of PEG-hemoglobin along with air breathing to mice bearing the EMT-6 tumor increased tumor cell killing by cyclophosphamide, BCNU, adriamycin and taxol without increasing toxicity to the bone marrow CFU-GM. PEG-Hemoglobin given prior to each dose of chemotherapy increased the tumor growth delay produced by cyclophosphamide, adriamycin, 5-fluorouracil, BCNU and taxol in a manner with increased level of inspired oxygen and with a concomitant decreased in lung metastases.

CONCLUSIONS

Further investigation of PEG-hemoglobin as an oxygen delivery agent in oncology is warranted.

Interaction of interleukin-11 (rhIL-11) with cytotoxic therapies in the human HT-29 colon carcinoma

The cytokine interleukin-11 (rhIL-11) has been shown to enhance the recovery of bone marrow, oral epithelium and intestinal crypt cells after cytotoxic insult by anticancer drugs or ionizing radiation. 5-Fluorouracil based chemotherapy and radiation therapy are frequently used in the treatment of colon cancer. Simultaneous exposure of human HT-29 colon carcinoma cells in culture to rhIL-11 and 5-fluorouracil for 24 h resulted in enhanced cell killing of the HT-29 cells with lower concentrations (1-10 mu M) of 5-fluorouracil compared with the drug alone. Exposure of HT-29 cells to rhIL-11 prior to, during and after radiation delivery did not alter the killing of normally oxygenated or hypoxic HT-29 cells by the radiation. In vivo treatment of nude mice bearing HT-29 colon tumor xenografts with rhIL-11 prior to and during administration of 5-fluorouracil did not alter the killing of the tumor cells or the killing of the bone marrow CFU-GM by the drug. In the tumor growth delay experiments, administration of rhIL-11 to nude mice bearing HT-29 colon tumor xenografts did not alter the growth of the tumor and did not alter the response of the tumor to 5-fluorouracil. However, administration of rhIL-11 to these animals increased the response of the tumor to fractionated radiation therapy resulting in a radiation dose-modifying factor of 1.5+/-0.2. These results indicate that rhIL-11 may be a selective protector of normal tissues without affecting the response of the tumor to therapy.

Reversal of in vivo drug resistance by the transforming growth factor-beta inhibitor decorin

Transforming growth factor-beta (TGF-beta) has been implicated in the in vivo resistance of the EMT-6/CTX and EMT-6/ CDDP murine mammary tumors. Both of these tumors have a higher number of intratumoral vessels than the EMT-6/ parent tumor. Animals bearing the resistant tumors have higher plasma levels of TGF-beta than animals bearing the parent tumors; however, upon treatment with cytotoxic therapies there is a greater rise in plasma TGF-beta levels in animals bearing the parent tumor than in animals bearing the resistant tumors. In situ hybridization for TGF-beta mRNA and immunohistochemical staining for TGF-beta protein showed that the resistant tumor levels of this growth factor are higher than those of the parent tumor prior to treatment; however, after cytotoxic therapy the increase in TGF-beta is greater in the parent tumor than in the resistant tumors. Treatment of tumor-bearing animals with the naturally occurring TGF-beta inhibitor decorin did not alter the sensitivity of the parent tumor to cyclophosphamide or to CDDP as determined by tumor cell survival assay. However, administration of decorin increased the sensitivity of the EMT-6/CTX tumor to cyclophosphamide and of the EMT-6/CDDP tumor to CDDP so that the drug resistance of these tumors was nearly ablated. A similar pattern was observed in the drug response of the bone marrow granulocyte-macrophage colony-stimulating factor of animals bearing each of the 3 tumors.

Interaction of interleukin-11 with cytotoxic therapies in vitro against CEM cells and in vivo against EMT-6 murine mammary carcinoma

Interleukin-11(rhIL-11) is a cytokine that has been shown to enhance the recovery of bone marrow and intestinal crypt cells after cytotoxic insult with radiation or anticancer drugs. The current study examined the effects of rhIL-11 on the response of CEM human lymphoblastic leukemia cells and on the EMT-6 murine mammary carcinoma in vivo to cytotoxic anticancer therapies. Exposure of CEM cells to rhIL-11 for 24 hr did not alter the cytotoxicity of melphalan or radiation, increased the cytotoxicity of CDDP (100 muM) and 4-hydroperoxycyclophosphamide (50 betaM) and decreased the cytotoxicity of 5-fluorouracil and ara-C toward the cells. Treatment of mice bearing the EMT-6 tumor with rhIL-11 twice daily for 4 days prior to and the day of cytotoxic therapy resulted in no significant change in the tumor cell killing or bone marrow CFU-GM killing by melphalan, cyclophosphamide, thiotepa, CDDP, radiation, 5-fluorouracil or ara-C. Administration of rhIL-11 twice per day on days 7-18 to EMT-6 tumor bearing animals receiving high dose chemotherapy (melphalan, thiotepa or cyclophosphamide) as a single dose on day 7 followed by mobilized peripheral blood cells on day 8 and rhG-CSF on days 8-20, tended to prolong the tumor growth delay produced by the drugs. This rhIL-11 treatment also resulted in a more rapid recovery of white blood cells and granulocytes in the animals. Furthermore, animals treated with rhIL-11 had improved survival rates compared with animals receiving all other normal tissue support without rhIL-11.

Relationship of cellular energy parameters to cytotoxicity for AG-17, lonidamine and cyclocreatine in four human tumor cell lines

The cytotoxicity and effect on cellular energy parameters of AG-17, lonidamine and cyclocreatine were examined in four human tumor cell lines: MCF-7 breast carcinoma, SW2 small cell lung carcinoma, A2058 melanoma and A2058-055, a subline of A2058 transfected with the creatine kinase gene. Although these cell lines had widely differing levels of creatine kinase activity, there were no differences in their sensitivity to cyclocreatine. The MCF-7 cells were most sensitive to AG-17 and to lonidamine with 90% cell killing by 50 mu M and 115 mu M of the drugs after 72 h exposure, respectively. The percent of coupled respiration in the cells was 60-70% in the absence of drug exposure and was decreased to 30-40% after 24 h of exposure to each of the drugs. Cytochrome C oxidase activity was decreased by 8- to 9-fold in the high creatine kinase expressing cell lines (SW2 and A2058-055) after exposure to AG-17 (250 mu M) for 24 h. Lonidamine (250 mu M) exposure decreased hexokinase activity in the cells to 30-40% of normal in 24 h. Extra-cellular lactate levels increased most markedly in the media of the MCF-7 and SW2 cells exposed to AG-17 (100 and 250 mu M) for 24 h. Although no specific enzymatic target was effected, cyclocreatine exposure resulted in a decrease in the ATP content of the cells, especially in the MCF-7 cells where ATP was decreased to 30% of normal upon 24 h exposure to the drug. These results provide a rationale for the use of these agents in combination with each other or in combination with cytotoxic anticancer therapies targeted on cellular DNA.

Comparison of several antiangiogenic regimens alone and with cytotoxic therapies in the Lewis lung carcinoma

The efficacy of several potential antiangiogenic agents, TNP-470, minocycline, suramin, genistein, interferon delta 4, 14(sulfated)-beta-cyclodextrin and tetrahydrocortisol, alone and in combination with cytotoxic therapies was examined against primary and metastatic Lewis lung carcinoma. The antiangiogenic agents when administered as single agents or in two-agent combinations were only modestly active as antitumor agents. Three antiangiogenic agent combinations, TNP-470/minocycline, TNP-470/14(SO4)beta-CD/THC and minocycline/14(SO4)beta-CD/THC, produced significant increases in tumor growth delay and decreases in the number of lung metastases when administered along with cyclophosphamide compared with cyclophosphamide alone. Two antiangiogenic agent combinations, minocycline/interferon delta 4 and minocycline/14(SO4)beta-CD/THC, produced significant decreases in the number of lung metastases when administered alone with adriamycin compared with adriamycin alone. The antiangiogenic combinations of TNP-470/minocycline, TNP-470/suramin, TNP-470/genistein, TNP-470/interferon delta 4 and TNP-470/l4(SO4)beta-CD/THC, resulted in increased tumor growth delays when administered along with CDDP, BCNU, fractionated radiation or 5-fluorouracil. There was not always a direct correlation between the antiangiogenic regimen that was most beneficial against the primary tumor as compared with disease metastatic to the lungs. These studies establish that a broad range of antiangilogenic therapies can interact in a positive manner with cytotoxic therapies.

Transforming growth factor-beta in in vivo resistance

The potential role of transforming growth factor-beta in in vivo resistance was examined by administration of transforming growth factor-beta-neutralizing antibodies to animals bearing the EMT-6/Parent tumor or the antitumor alkylating resistance tumors, EMT-6/CTX or EMT-6/CDDP. Treatment of tumor bearing animals with anti-TGF-beta antibodies by intraperitoneal injection daily on days 0-8 post-tumor cell implantation increased the sensitivity of the EMT-6/Parent tumor to cyclophosphamide (CTX) and cisplatin (CDDP) and markedly increased the sensitivity of the EMT-6/CTX tumor to CTX and the EMT6/CDDP tumor to CDDP, as determined by tumor cell survival assay. Bone marrow granulocyte-macrophage colony-forming units (CFU-GM) survival was determined from these same animals. The increase in the sensitivity in the tumors upon treatment with the anti-TGF-beta antibodies was also observed in increased sensitivity of the bone marrow CFU-GM to CTX and CDDP. Treatment of non-tumor-bearing animals with the anti-TGF-beta regimen did not alter blood ATP or serum glucose level but did decrease serum lactate levels. This treatment also decreased hepatic glutathione, glutathione S-transferase, glutathione reductase, and glutathione peroxidase in non-tumor bearing animals by 40-60% but increased hepatic cytochrome P450 reductase in these normal animals. Animals bearing the EMT-6/CTX and EMT-6/CDDP tumors had higher serum lactate levels than normal or EMT-6/Parent tumor-bearing animals; these were decreased by the anti-TGF-beta regimen. Treatment of animals bearing any of the three tumors with the anti-TGF-beta regimen decreased by 30-50% the activity of hepatic glutathione S-transferase and glutathione peroxidase, and increased by 35-80% the activity of hepatic cytochrome P450 reductase. In conclusion, treatment with transforming growth factor-beta-neutralizing antibodies restored drug sensitivity in the alkylating agent-resistant tumors, altering both the tumor and host metabolic states.

In vivo studies with interleukin-12 alone and in combination with monocyte colony-stimulating factor and/or fractionated radiation treatment

Interleukin-12 (IL-12) was found to be an active anti-tumor agent in 3 established murine solid tumors: B16 melanoma, Lewis lung carcinoma and renal cell carcinoma (RenCa). IL-12 was well tolerated over a 100-fold dose range. Only the high-dose treatment of IL-12 resulted in a clear reduction in the number of lung metastases from B16 melanoma and Lewis lung carcinoma. Treatment of animals bearing Lewis lung carcinoma with IL-12 in combination with fractionated radiation therapy was markedly dose-modifying, indicating that IL-12 was acting synergistically with radiation. Treatment of animals bearing the same tumor with monocyte colony-stimulating factor (M-CSF) along with fractionated radiation therapy resulted in a parallel increase in tumor growth delay with increasing dose of M-CSF, indicating that M-CSF was affecting a subpopulation of tumor cells in addition to those killed by radiation therapy. The combination of IL-12 with M-CSF was most effective with radiation therapy, especially in the clinically relevant dosages of 2 and 3 Gy per fraction. By isobologram analysis, IL-12 and M-CSF, along with fractionated radiation therapy, resulted in a greater-than-additive (synergistic) tumor response.

Lisofylline as a modifier of radiation therapy

Lisofylline is a new methylxanthine. The potential of lisofylline to enhance the response to ionizing radiation of the EMT-6 murine mammary carcinoma in vitro and in vivo was assessed and compared with pentoxifylline. Addition of lisofylline (100 microM) or pentoxifylline (100 microM) from the time of radiation exposure and throughout the time of colony formation did not alter the response of normally oxygenated EMT-6 cells to gamma-radiation delivered at 0.76 Gy/min or 12.3 Gy/min. The dose modifying factor for hypoxic EMT-6 cells by lisofylline or pentoxifylline and radiation delivered at 0.76 Gy/min was 2.3. Higher dose rate radiation (12.3 Gy/min) was more cytotoxic toward hypoxic EMT-6 cells than lower dose rate radiation. The dose modifying factor produced by lisofylline in the high dose rate radiation setting was 1.2. In vivo, using the tumor cell survival assay, lisofylline decreased the shoulder of the radiation survival curve (0.76 Gy/min) by a factor of 1.7 +/- 0.2 while pentoxifylline did not. In the tumor growth delay assay, administration of multiple doses of lisofylline or pentoxifylline along with single dose radiation (0.76 Gy/min) was 1.3, while the radiation dose modifying factor for lisofylline or pentoxifylline administered by continuous infusion was 1.5. Overall, lisofylline was a more effective modifier of gamma-radiation therapy than pentoxifylline, and further investigation of lisofylline in this setting is warranted.

Whole-body hyperthermia and lonidamine as adjuvant therapy to treatment with cisplatin with or without local radiation in mouse bearing the Lewis lung carcinoma

The Lewis lung carcinoma implanted subcutaneously in the hind leg of a C57BL mouse metastasizes avidly to the lungs of the host. This tumour model system thus allows assessment of both primary and metastatic disease to treatment. Lonidamine (50 mg/kg) administered once or twice daily produced approximately additive tumour growth delay with whole-body hyperthermia (60 min to 42 degrees C and 60 min at 42 degrees C). The addition of lonidamine to treatment with cisplatin (10 mg/kg) and whole-body hyperthermia continued to produce increased tumour growth delay of up to 14.7 days compared with 10.8 days for cisplatin/whole-body hyperthermia. The response of the metastatic disease paralleled that of the primary tumour with a reduction in the number and percent of large metastases (> 3 mm) on day 20 post-tumour implantation. The addition of local fractionated radiation therapy (3 Gy x 5) to the primary tumour produced a very effective treatment regimen resulting in 37.5 days of tumour growth delay along with twice daily lonidamine/cisplatin whole-body hyperthermia. With this treatment regimen there was also a reduction to 50% of control of the number of lung metastases as well as the percent of large metastases on day 20. Further investigation of these treatment combinations is warranted.

Hyperthermia and platinum complexes: time between treatments and synergy in vitro and in vivo

To investigate the greatest therapeutic efficacy, we investigated the effect of scheduling on the cytotoxic interaction between hyperthermia and seven different platinum complexes in vitro and in vivo using the FSaII murine fibrosarcoma cells. Hyperthermia treatment (43 degrees C, 1 h) was administered at various times relative to exposure of the cells to the IC90 (at 37 degrees C, 1 h) of each platinum complex. Greater-than-additive killing of FSaII cells was obtained with cis-diamminedichloroplatinum (II) (CDDP) and hyperthermia when the drug and heat exposure were overlapping simultaneous. The same cell killing effect with carboplatin and hyperthermia resulted from heat exposure up to 5 h prior to, simultaneous with, or immediately after the drug exposure D-Tetraplatin and K2PtCl4 were synergistic with hyperthermia only if the drug and heat exposure were simultaneous. PtCl4(Nile Blue)2 and hyperthermia produced greater-than-additive cell killing if the heat and drug exposure occurred in immediate sequence, simultaneously, or with drug exposure up to 5 h prior to heat exposure. PtCl4(Rh-123)2 and hyperthermia produced greater-than-additive cell killing if the drug and heat occurred in immediate sequence, overlapping, or simultaneously. PtCl4(Fast Black)2 and hyperthermia were additive over a wide range of scheduling from heat exposure 2 h prior to 5 h after drug exposure. When animals bearing FSaIIC tumours were treated with single doses of CDDP (10 mg/kg). carboplatin/PtCl4(Nile Blue)2 (50 mg/kg), PtCl4(Rh-123)2/PtCl4(Fast Black)2 (100 mg/kg) under various combined schedules with hyperthermia treatment (43 degrees C, 30 min), similar cytotoxicity patterns were observed. To administer hyperthermia at a time when the drug concentration in the tumour tissue is at peak level, careful scheduling of systemically administered anticancer drugs with hyperthermia is needed. Modelling studies can identify the stringency/flexibility of drug/heat scheduling to achieve synergistic tumour cell killing.

Influence of an anti-angiogenic treatment on 9L gliosarcoma: oxygenation and response to cytotoxic therapy

Tissue oxygen tensions were measured in subcutaneously growing rat 9L gliosarcoma under normal air and carbogen breathing conditions prior to and after i.v. administration of a perflubron emulsion. When these animals were treated with the anti-angiogenic agents TNP-470 and minocycline for 5 days prior to oxygen measurement, tumor hypoxia was decreased compared with untreated tumors. Hypoxia, defined as the percent of pO2 readings < or = 5 mm Hg, was decreased from 71% in untreated air-breathing controls to 34% in animals treated with the anti-angiogenic agents, the perflubron emulsion and carbogen breathing. These effects were manifest in the increased response of the tumor to single-dose (10, 20 and 30 Gy) radiation therapy. Twenty-four hours after treatment with BCNU oxygenation of the tumors was not altered; however, 24 hr after administration of adriamycin oxygenation of the tumors was increased such that hypoxia in adriamycin-treated tumors in animals receiving the perflubron emulsion and carbogen was reduced to 21%. Tumor growth delay in the s.c. tumors was increased by the addition of treatment with the anti-angiogenic agents from day 4 through day 18 post-tumor cell implantation along with BCNU or adriamycin on days 7-11. Administration of the perflubron emulsion and carbogen breathing resulted in increased tumor growth delay with the chemotherapeutic agents alone and in combination with the anti-angiogenic agents. Life span in animals bearing intracranially implanted 9L gliosarcoma progressively increased with administration of the anti-angiogenic agents and then the anti-angiogenic agents and perflubron emulsion/carbogen compared to treatment with BCNU or adriamycin.

Restoration of tumor oxygenation after cytotoxic therapy by a perflubron emulsion/carbogen breathing

PURPOSE

Hypoxic cells are presumed to be an obstacle to successful cancer treatment because these cells are protected from the cytotoxic effects of radiotherapy and certain anti-cancer drugs. The current study was conducted to determine the effect of cytotoxic therapy on tumor oxygenation and the effect of administration of a perfluorochemical emulsion/carbogen breathing treatment on tumor oxygenation after cytotoxic therapy.

MATERIALS AND METHODS

Female Fisher 344 rats bearing 13762 mammary carcinoma cells implanted subcutaneously in a hindlimb were treated with standard therapeutic single doses of anti-tumor treatments of several types, including alkylating agents (cisplatin, melphalan, cyclophosphamide); natural products (doxorubicin, paclitaxel, etoposide); antimetabolites (fluorouracil); hypoxic cell-selective agents (mitomycin, SR-4233); and fractionated irradiation (3 Gy/day for 5 days). The oxygen levels in the tumors were measured with an Eppendorf PO2 histograph before the treatment and 24 hours after treatment under air breathing and carbogen breathing conditions, and after administration of a perflubron emulsion under air breathing and carrbogen breathing conditions. Fifty to 60 points were measured per tumor, and 8 to 10 tumors made up each group.

RESULTS

The tumors were more hypoxic after treatment with every anticancer treatment. The percentage of PO2 readings < or = 5 mmHg in the untreated tumors was 49% and ranged from 85% (radiotherapy) to 59% (etoposide) in the treated tumors. Administration of the perflubron emulsion (8 mL/kg) and carbogen breathing (95% O2/5% CO2) increased the oxygenation of the tumors such that the percentage of PO2 readings < or = 5 mmHg was 32% in the untreated control tumors and ranged from 27% (radiotherapy) to 56% (doxorubicin) in the treated tumors. There was a direct correlation between the level of tumor cell killing and the increased oxygenation observed in the tumor.

CONCLUSION

Tumors may be more hypoxic after an effective dose of a cytotoxic therapy, and administration of a perflubron emulsion/carbogen mixture can increase the tumor oxygen content when hypoxia is the result of cytotoxic therapy. Hypoxia produced by therapy may be regarded as a mechanism of resistance that leads to diminished tumor cell killing with subsequent doses of drugs or radiation. The restoration of tumor oxygenation by the perflubron emulsion/carbogen breathing may provide a clinically relevant means of overcoming at least in part hypoxia-related resistance.