Hussein Abou-Issa

Ibuprofen-induced inhibition of cyclooxygenase isoform gene expression and regression of rat mammary carcinomas.

A single dose of 75 mg/kg 7,12 dimethylbenz[a]anthracene was administered to 50-day-old virgin female Sprague-Dawley rats and 100 days later, animals were randomized and provided with Teklad rodent chow mixed with a dose of 25 mg/rat/day ibuprofen for 35 days. Ibuprofen treatment reduced tumor volume (P < 0.05) and significantly inhibited gene expression of both cyclooxygenase- and cyclooxygenase-2 (P < 0.02). These results indicate that ibuprofen induced significant regression of established mammary carcinomas which was associated with inhibition of expression of isoforms of the gene responsible for prostaglandin production.

Growth suppression of human breast carcinoma cells in culture by N-(4-hydroxyphenyl)retinamide and its glucuronide and through synergism with glucarate

The inhibitory effects of N-(4-hydroxyphenyl)retinamide (HPR) and its glucuronide derivative on the growth of MCF-7 human breast cancer cells in vitro were compared. The results indicate that the glucuronide had slightly greater potency and much less cytotoxicity than the free retinoid. At a concentration of 10(-6) M, HPR inhibited MCF-7 cell growth by approximately 25%, whereas an equimolar concentration of the glucuronide caused a 40% growth inhibition. Higher concentrations of HPR were highly cytotoxic. At a 10(-5) M concentration of the glucuronide, cell viability was 77%, and 65% of the cells were able to resume growth. On the other hand, at 10(-5) M HPR, cell viability dropped to 49%, and only 15% of the cells were capable of resuming growth. The lower cytotoxicity and higher potency of the retinoid glucuronide compared to the parent retinamide suggest that the conjugate may have a chemotherapeutic advantage over the parent compound. The apparent higher efficacy of HPR in combination with glucarate (GT) compared to the single agents could be due to increased net formation of HPR glucuronide conjugate following conversion of GT to the beta-glucuronidase inhibitor, D-glucaro-1,4-lactone. However, HPLC analysis of the cell metabolites did not show any detectable levels of the retinoid glucuronide upon treatment of MCF-7 cells with HPR and GT.

Potential biochemical markers for infantile autism

Biochemical markers are crucial to the development of early diagnosis of infantile autism. The blood concentrations of neuroanalytes epinephrine, norepinephrine, dopamine, and serotonin were elevated in autistic subjects (n = 13) as compared to normal controls (n = 10). Autistic subjects had peptide patterns (peaks I-V, Sephadex G-25) that were different from those of normal controls. Methionine-enkephalin has been tentatively identified from fraction I of autistic subjects by HPLC as one of a large number of peptides that appears to be elevated. The HPLC chromatographic patterns of fraction V from all autistic subjects show a peak with retention time of 7.6 min. The HPLC of control urine fraction V revealed no comparable peaks.

Antineoplastic properties of Maharishi-4 against DMBA-induced mammary tumors in rats

Maharishi-4 (M-4), an ayurvedic food supplement, was tested for anticarcinogenic and anticancer properties against 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in rats. The 6% M-4-supplemented diet protected DMBA-induced carcinogenesis by reducing both tumor incidence and multiplicity during initiation and promotion phases. The control animals who developed tumors when supplemented with M-4 diet for four weeks showed tumor regression in 60% of cases. There was no significant difference in the food intake or weight gain in rats who were on M-4-supplemented diet compared to control group. Possible mechanisms of action of M-4 are discussed.

Caffeine and unsaturated fat diet significantly promotes DMBA‐induced breast cancer in rats

The following study was carried out to determine the possibility of caffeine being a promoter of breast cancer development in animals consuming vegetable fat. A controlled study, comparing the time of mammary tumor development and the number of tumors was carried out in Sprague‐Dawley rats which had been given 20 mg of DMBA at seven weeks of age. This study evaluated the tumor promotional effects of caffeine alone, caffeine and unsaturated fat in combination, unsaturated fat alone, and a standard rat chow diet. The results show that the rats which consumed caffeine and unsaturated fat had the earliest development of tumor and the most multiple tumor occurrence. Average time to tumor development was 95 days. The fat or standard chow rats had an average time to tumor development of 134 and 140 days, respectively. The caffeine‐alone rats had a mean time to tumor development of 188 days. The combination of an unsaturated fat diet and caffeine significantly shortened the time to tumor development when compared with the other three groups.

Anticarcinogenic effect of retinoids on 7,12-dimethylbenz(a)anthracene-induced mammary tumor induction, and its relationship to cyclic AMP-dependent protein kinase

Administration of 13-cis retinoic acid and N-(4-hydroxyphenyl) retinamide daily in the diet to female Sprague-Dawley rats beginning one day after intubation with 7,12-dimethylbenz(a)anthracene (DMBA) prolonged the latency periods and inhibited the percentage incidence of mammary tumors. A significant reduction in the total number of tumors was also evident. The inhibition of mammary tumor growth by retinoids was associated with a significant increase (3-fold) in cytosolic cAMP-binding and histone kinase activities. The increase of histone kinase activity was almost totally in the cAMP-dependent protein kinase Type II. Retinoic acid increased the amount of the regulatory subunit (R11) rather than altering its cAMP binding affinity. These results suggest that cAMP-dependent protein kinase Type II may be involved in mediating the retinoid action in the inhibition of mammary tumor growth in vivo.

An unhydrolyzable analogue of N-(4-hydroxyphenyl)retinamide: synthesis and preliminary biological studies

The synthesis of a nonhydrolyzable, carbon-linked analogue (4-HBR) of the retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) using Umpolung methods is described. Preliminary studies of biological activity show 4-HBR is similar to 4-HPR in its actions although a potentially relevant and desirable difference is its reduced suppression of plasma vitamin A levels. These results show that 4-HPR does not have to be hydrolyzed to retinoic acid to produce its chemotherapeutic effects.

Effect of dietary soybean and licorice on the male F344 rat: An integrated study of some parameters relevant to cancer chemoprevention

The individual and combined effects of dietary toasted soybean meal (3.13-25%) and dietary licorice root extract (0.38-3.0%) on selected liver and intestinal enzyme levels and on clinical chemistry and histopathological parameters were evaluated on male F344 rats. All parameters were measured one and three months after the 50-day-old rats were started on the diets. By use of newly developed high-performance liquid chromatography-based analytic methods, measurable levels of daidzein (2.67 micrograms/ml) and glycyrrhetinic acid (7.87 micrograms/ml) were detected in the sera of rats on the 25% soybean and 3% licorice diets, respectively. Histopathological evaluations of organs and tissues yielded only nonsignificant strain-related changes. At all dosages, there were no significant soybean- or licorice-related anatomic lesions or hematologic changes. In the clinical biochemistry profile, soybean meal caused moderate but significant dose-dependent decreases in serum cholesterol and increases in alkaline phosphatase, blood urea nitrogen, and phosphorus, which remained within the normal range. Liver glutathione transferase, catalase, and protein kinase C showed significant inductions (up to 50%) in response to increasing doses of soybean meal and licorice extract, with evidence for only marginal interaction between the two additives. Their effects on the intestinal mucosa were not significant. Ornithine decarboxylase levels, an indicator of promotional activity, were unchanged or repressed by the additives. The favorable effects of up to 25% toasted soybean meal and 3% licorice root extract on the levels of the four enzymes, without unfavorable changes in clinical parameters, might account in part for the chemopreventive activities of these additives. These effects would be in addition to direct inhibitory effects of known components in these additives on these or other enzymes or modulation of hormone activity that is not evaluated in this study.

An improved synthesis of the C-linked glucuronide of N-(4-hydroxyphenyl)retinamide.

Retinoic acid analogues such as N-(4-hydroxyphenyl)retinamide (4-HPR) are effective chemopreventatives and chemotherapeutics for numerous types of cancer. The C-linked analogue of the O-glucuronide of 4-HPR (4-HPRCG) has been shown to be a more effective agent. The synthetic route to this molecule has been significantly improved by access to a key C-benzyl-glucuronide intermediate through employment of a Suzuki coupling reaction between an exoanomeric methylene sugar and an aryl bromide. Preliminary evidence shows 4-HPRCG has chemotherapeutic activity.

Synergistic interaction between 13-cis-retinoic acid and glucarate: activity against rat mammary tumor induction and MCF-7 cells

At high dietary levels in vivo, both 13-cis-retinoic acid and calcium glucarate inhibit the induction of rat mammary tumors by 7,12-dimethylbenz(a)anthracene. The present study shows that sub-optimal dietary levels of each, which individually have no effect on tumor induction, when combined together in the diet, significantly increases tumor latency and suppresses tumor frequency in the rat system. Weight gain of animals was similar in control and experimental groups. Furthermore, ineffective sub-optimal dosages of glucarate and 13-cis-retinoic acid interacted synergistically to inhibit the growth in vitro of the MCF-7 human breast cancer cells. By varying the concentrations of glucarate and 13-cis-retinoic acid independently, evidence was obtained that in combination glucarate may play an adjuvant role, with the retinoid as the effector. Thus, the results of this experimental animal study demonstrate for the first time the potential use in synergistic combination of 2 normal metabolites in non-toxic chemoprevention and chemotherapy.