Developmental effects of prenatal exposure to bisphenol a on the uterus of rat offspring

Exposure to estrogenic compounds during critical periods of fetal development could result in adverse effects on the development of reproductive organs that are not apparent until later in life. Bisphenol A (BPA), which is employed in the manufacture of a wide range of consumer products, is a prime candidate for endocrine disruption. We examined BPA to address the question of whether in utero exposure affects the uterus of the offspring and studied the expression and distribution of the estrogen receptors alpha (ERalpha) and beta (ERbeta), because estrogens influence the development, growth, and function of the uterus through both receptors. Gravid Sprague-Dawley dams were administered by gavage either 0.1 or 50 mg/kg per day BPA or 0.2 mg/kg per day 17alpha-ethinyl estradiol (EE2) as reference dose on gestation days 6 through 21. Female offspring were killed in estrus. Uterine morphologic changes as well as ERalpha and ERbeta distribution and expression were measured by immunohistochemistry and Western blot analysis. Striking morphologic changes were observed in the uterine epithelium of postpubertal offspring during estrus of the in utero BPA-treated animals (the thickness of the total epithelium was significantly reduced). ERalpha expression was increased in the 50-mg BPA and EE2-treated group. In contrast, we observed significantly decreased ERbeta expression in all BPA- and EE2-treated animals when compared with the control. In summary, these results clearly indicate that in utero exposure of rats to BPA promotes uterine disruption in offspring. We hypothesize that the uterine disruption could possibly be provoked by a dysregulation of ERalpha and ERbeta.     

围生期双酚A暴露对大鼠雌性子代生殖系统及雌激素受体表达的影响

目的：研究围生期双酚A（Bisphenol A,BPA）暴露对SD大鼠子代生殖系统的影响及雌激素受体（Estrogen Receptor,ER）表达的改变。方法：经灌胃给予围生期孕鼠0、5、50、500mg/（kg.d）的BPA,观察雌性子代生殖器官重量、病理学改变、子宫ERα、β及磷酸化ERK（p-ERK）与总ERK（T-ERK）蛋白表达的改变,并通过子宫增重实验检测子宫对雌二醇（E2）敏感性的改变。结果：500mg/kg BPA可引发亲代中毒症状及子代体重下降（P〈0.05）,50mg/kg BPA可明显增加雌性子代体重及子宫重量,BPA各剂量组均可使子宫内膜增厚及相对比例增加,子宫增重和子宫相对增殖率增加,并提高ERα与p-ERK蛋白表达,而对ERβ无影响。结论：BPA围生期暴露可引起子代子宫组织ER蛋白表达变化,并可提高子宫对E2的敏感性。     

Transplacental effect of diethylstilbestrol in female rats.

The effect of diethylstilbestrol propionate (DES; 1 mg/kg body wt. was studied in the female offspring of rats exposed subcutaneously on the 19th day of gestation. Examination of vaginal smears showed persistent estrus in adult rats treated prenatally with DES. Compensatory ovarian hypertrophy (COH) induced by hemicastration of these rats was not suppressed by estrogens. A per oral test for glucose-tolerance revealed decreased utilization of glucose in the offspring of DES-treated rats. Preliminary observations demonstrated that tumors developed in 14 of 18 (77.8%) progeny transplacentally expoed to DES and in 9 of 34 (26.5%) intact control rats. Tumors of the ovary and the endometrium were found only in the rats treated prenatally with DES; no tumors of the uterine cervix or vagina were observed in either experimental or control groups. It is suggested that a transplacental effect of DES in the female is impairment of the sex differentiation of the hypothalamus. The resulting hormonal and metabolic shifts might promote tumorigenesis.     

Perinatal Exposure to Bisphenol A or Diethylstilbestrol Increases the Susceptibility to Develop Mammary Gland Lesions After Estrogen Replacement Therapy in Middle-Aged Rats

The development of the mammary gland is a hormone-regulated event. Several factors can dysregulate its growth and make the gland more susceptible to cellular transformation. Among these factors, perinatal exposure to xenoestrogens and hormone replacement therapy has been associated with increased risk of developing breast cancer. Here, we assessed the effects induced by estrogen replacement therapy (ERT) in ovariectomized (OVX) middle-aged rats and whether perinatal exposure to diethylstilbestrol (DES) or bisphenol A (BPA) modified these effects in the mammary gland. Pregnant rats were orally exposed to vehicle, 5 μg DES/kg/day, or 0.5 or 50 μg BPA/kg/day from gestational day 9 until weaning. Then, 12-month-old offspring were OVX and treated with 17β-estradiol for 3 months. Morphological changes and the percentage of epithelial cells that proliferated or expressed estrogen receptor alpha (ESR1) and progesterone receptor (PR) were analyzed in mammary gland samples of 15-month-old animals. ERT induced lobuloalveolar hyperplasia and ductal cysts in the mammary gland of middle-aged rats, associated with a higher proliferation index of epithelial cells. Perinatal exposure to DES followed by ERT increased the number of cysts and induced the formation of fibroadenoma and ductal carcinoma in situ, without modifying the expression of ESR1 or PR. Also, after 3 months of ERT, BPA-exposed rats had a higher incidence of ductal hyperplasia and atypical lobular hyperplasia than animals under ERT alone. In conclusion, perinatal exposure to xenoestrogens increases the susceptibility of the mammary gland to develop cysts and hyperplastic lesions when confronted with ERT later in life.     

子宫营养试验检测双酚A的雌激素样活性

目的: 采用子宫营养试验,检测双酚A(BisphenolA,BPA)的雌激素样活性,初步探讨其作用机制.方法:未成年SD雌性大鼠(21d)100只,分为BPA 200 mg/kg、400 mg/kg和800 mg/kg 3个剂量组,溶剂对照组(花生油)和阳性对照组(苯甲酸雌二醇,Estradiol Benzoate,E-2B)0.4 mg/kg,每天一次灌胃给药,连续给予3 d和7 d.于末次给药的第24 h处死动物取子宫.结果:3 d和7 d两个时段,E-2B、BPA 400 mg/kg和800 mg/kg 2个剂量组子宫湿重、子宫/体重比、平滑肌厚度和宫腔上皮高度与溶剂对照组相比有显著性差异(P<0.01),有明显的剂量效应关系.给予BPA 7 d还使未成年SD雌性大鼠阴道开口时间提前.结论:BPA具有弱雌激素样效应,子宫湿重增加可能与平滑肌增生有关.     

Fulvestrant (Faslodex) -- how to make a good drug better

Fulvestrant (Faslodex); AstraZeneca Pharmaceuticals, Wilmington, DE) is an estrogen receptor (ER) antagonist with a novel mode of action; it binds, blocks, and increases degradation of ER. Fulvestrant (at the approved dose [250 mg/month]) is at least as effective as anastrozole (1 mg/day) in the treatment of postmenopausal women with hormone receptor-positive advanced breast cancer (HR(+) ABC) progressing or recurring on antiestrogen therapy, and is also an active first-line treatment. Although fulvestrant (250 mg/month) is clearly effective, it takes 3-6 months to achieve steady-state plasma levels. Steady-state concentrations are approximately twofold higher than those achieved with a single dose; reaching this earlier, for example, via a loading-dose (LD) regimen (250 mg/month plus 500 mg on day 0 and 250 mg on day 14 of month 1), may allow responses to be achieved more quickly and limit the possibility of early relapse. Fulvestrant high-dose (HD) regimens (500 mg/month) offer the possibility of greater antitumor activity, because (a) ER downregulation is a dose-dependent process (an approximately 70% reduction is observed with a single 250 mg dose of fulvestrant) and (b) evidence correlates greater ER downregulation with superior efficacy. A fulvestrant HD regimen offers the potential of achieving near 100% ER downregulation. There is also potential to increase fulvestrant-ER binding by reducing plasma estrogen levels, for example, with concomitant aromatase inhibitor treatment. Several ongoing trials use LD, HD, and combination regimens; results from these studies are awaited with interest. Meanwhile, fulvestrant (250 mg/month) remains a valuable additional endocrine treatment for postmenopausal women with HR(+) ABC recurring or progressing on antiestrogen therapy.     

Influence of perinatal genistein exposure on the development of MNU-induced mammary carcinoma in female Sprague-Dawley rats

Genistein, a phytoestrogen, was subcutaneously (s.c.) injected to pregnant Sprague-Dawley CD rats on gestational days 16-20 at either 25 mg (Group 1) or 5 mg/day (Group 2). Female offspring of mothers not exposed to genistein during pregnancy received 12.5 mg genistein s.c. at neonatal days 15 and 18 (Group 3), or received vehicle only (Group 4). At 35 days of age, 4-9 female offspring from each group were autopsied to observe the influence of genistein, and remainder of female offspring received 50 mg/kg N-methyl-N-nitrosourea (MNU) intraperitoneally and were sacrificed when mammary tumors were larger than 1 cm in size or when they reached 35 weeks of age. Genistein treatment during the perinatal period resulted in lower body weight and lower relative uterine-ovarian weight at 35 days, and a prolonged estrus cycle with a long estrus phase at 12-16 weeks. However, at 35 days (time at MNU administration), mammary gland development, cell proliferation rate (PCNA labeling index), and the number of estrogen receptor (ER)- and progesterone receptor (PgR)-positive cells were similar between genistein-treated and untreated rats. Twenty-five or 5 mg genistein/day in utero (between days 16 and 20 of gestation) or 12.5 mg genistein/day on neonatal days 15 and 18 did not affect the incidence of mammary tumors > 1 cm or the latency but did increase the number of mammary cancer lesions when MNU was administered at the time when the mammary gland growth in genistein-treated and untreated rats was similar. Thus, perinatal genistein is an endocrine disrupter and increases the multiplicity of MNU-induced mammary carcinoma in rats.     

Estradiol and progesterone can prevent rat mammary cancer when administered concomitantly with carcinogen but do not modify surviving tumor histology,estrogen receptor alpha status or Ha-ras mutation frequency

An early full-term pregnancy is protective against mammary cancer in both humans and rodents. Treating rats with two hormones of pregnancy, estradiol and progesterone, for 5 weeks renders the rat mammary glands refractory to carcinogenesis. Our objectives was to determine if a shortened regimen (3 weeks) would be as effective as the 5-week regimen and to determine if the mammary gland was vulnerable to carcinogenic insult during the hormone treatments. We also examined cancers that survived the chemopreventive regimen to see if those tumors were particularly aggressive compared to control tumors (i.e., less differentiated, estrogen receptor alpha (ER alpha)-negative or harbored mutations in Ha-ras). In the first experiment, Lewis rats were injected with N-methyl-N-nitrosourea (MNU, 50 mg/kg) at 50 days of age. At 60 days of age, the rats were either mated and allowed to nurse their young for 3 weeks, treated with hormone vehicle for 5 weeks, or 17 beta-estradiol (E, 20 micrograms) and progesterone (P, 4 mg) 5 times per week for 3 or 5 weeks. All the rats exposed to MNU but not estradiol and progesterone developed multiple mammary cancers. Pregnancy reduced multiplicity to 0.40 cancers/rat. Treatments of estradiol and progesterone for 3 or 5 weeks reduced cancer multiplicity and increased latency to a similar degree as pregnancy. Mammary cancers from each group displayed a similar spectra of histologic class, estrogen receptor alpha (ER alpha) content and Ha-ras mutation status. In the second experiment, 50-day-old rats were treated for five weeks with either estradiol and progesterone or vehicle as above beginning at 60 days of age and treated with MNU at 50, 64, 78 or 92 days of age. In each case, estradiol and progesterone treatments resulted in significantly reduced mammary tumor frequency. These results demonstrate that a three-week regimen of estradiol and progesterone can protect the mammary gland from chemically-induced carcinogenesis even when carcinogen exposure occurs concomitant with estradiol and progesterone stimulation.     

Carcinogenicity of diethylstilbestrol in the Wistar rat: effect of postnatal oral contraceptive steroids

Diethylstilbestrol (DES) has been associated with vaginal neoplasia and malformations in humans. We have studied a test population of 504 female Wistar rats given diethylstilbestrol at from 0.0 to 0.5 mg/kg maternal body weight on days 18, 19, and 20 of gestation. Animals were euthanized in extremis, or at 2 years of age. The incidence of vaginal epithelial tumors was dose related. The types of epithelial tumors of the vagina were adenocarcinoma, squamous cell carcinoma, and mixed carcinoma, containing discrete adenomatous and squamous components. The incidence of vaginal epithelial tumors was determined to be dose related: rats exposed to 0 mg DES/kg maternal weight had an incidence of 0.6% (1 of 167 rats); 0.1 mg/kg, 4.1%; and 0.5 mg/kg, 4.3% (6 of 140); 25 mg/kg, 1.6% (1 of 63); and 50 mg/kg, 11.5% (3 of 26). Tumors of other reproductive tissues (mammary gland, ovary, oviduct, cervix, or uterus) demonstrated no discernible DES dose-response relationship. There was no oncogenic effect of postnatal administration of oral contraceptives (0 oral contraceptives, 31.25 micrograms/kg diet ethynylestradiol, and 31.25 micrograms/kg diet norethindrone or 104 micrograms/kg diet ethynylestradiol and 31.25 micrograms/kg diet norethindrone). Thus, vaginal tumors can be induced in a dose-related manner in the rat following in utero DES exposure. Oral contraceptive treatment did not increase the risk of neoplasia.     

Postnatal vaginal nodules induced by prenatal diethylstilbestrol treatment correlate with later development of ovary-independent vaginal and uterine changes in mice.

Pregnant ICR/JCL mice were given 4 daily subcutaneous injections of 0.2-2000 micrograms diethylstilbestrol (DES) starting on day 15 of gestation. Offspring of mothers given DES were killed at 1-10 days of age and examined for nodules of enlarged polygonal cells under the epithelium of the Müllerian (upper) vagina. Some offspring were ovariectomised at 30 days and killed at 120 days. The nodules which appeared in the prenatally DES-exposed mice (2-2000 micrograms/day) at 3-7 days were not connected with the epithelium of the sinus vagina and reacted positively to an antibody to epidermal growth factor. Nodule formation may prove to be prodromic of later ovary-independent vaginal changes in the DES-exposed mice. Epithelial stratification (2-2000 micrograms/day) and downgrowths and/or pegs (20-2000 micrograms/day) occurred in vaginae of ovariectomized mice exposed prenatally to DES; however, adenosis-like lesions occurred only in the offspring of mothers given the highest prenatal injections of 2000 micrograms DES. Wolffian remnants and hypospadias (2-2000 micrograms/day) were also encountered in the DES-exposed mice. Ovary-independent stratification of the uterine epithelium (20-2000 micrograms/day) and disorganization of the circular musculature (2-2000 micrograms/day) were also observed in the DES-exposed mice. None of these changes was found in ovariectomised 0.2 micrograms DES-exposed and control mice.     

A new irreversible aromatase inhibitor, 6-methylenandrosta-1,4-diene-3,17-dione (FCE 24304): antitumor activity and endocrine effects in rats with DMBA-induced mammary tumors

Summary The antitumor activity of the new irreversible aromatase inhibitor 6-methylenandrosta-1,4-diene-3,17-dione (FCE 24304) was studied in rats with 7,12-dimethylbenzanthracene (DMBA)-induced tumors; several endocrine parameters were evaluated in these animals. The compound was given s.c. and p.o. twice daily, 6 days/week, for 4 weeks. The control group showed 13% tumor regressions (0% complete remission, CR; 13% partial remission, PR). FCE 24304 given s.c. induced 44% (22+22) regressions at the dose of 3 mg/kg per day, 70% (40+30) at 10 mg/kg per day, 73% (27+46) at 30 mg/kg per day, and 70% (50+20) at 100 mg/kg per day. FCE 24304 given orally induced 25% (17+8) tumor regressions at 30 mg/kg per day and 50% (17+33) at 100 mg/kg per day. Rats were killed 4 h after the last dose and the aromatase activity of ovarian microsomes (OAA) was evaluated. OAA was reduced by 56% after s.c. treatment with 3 mg/kg per day FCE 24304; complete OAA suppression (96%) was obtained starting at 10 mg/kg per day s.c. Oral treatment slightly reduced OAA only at a dose of 100 mg/kg per day (36%). Body weight increased in all the groups s.c. treated with FCE 24304 but not in those treated orally. The weights of the pituitary, adrenals, and uterus were reduced in rats treated s.c. with 10 and 30 mg/kg per day; at 100 mg/kg per day, a decrease in ovarian weight was observed while uterus weight was similar to that of controls. Oral FCE 24304 increased ovarian weight at a dose of 30 mg/kg per day but not at 100 mg/kg per day. Serum prolactin (PRL) and luteinizing hormone (LH) levels did not change. In conclusion, FCE 24304 given s.c. proved highly effective against DMBA-induced tumors in rats but had less activity when given orally. Its intrinsic androgenic activity, higher after s.c. than after oral treatment, could contribute to the antitumor effect in the intact (premenopausal) rat model.     

Estrogen-independent activation of erbBs signaling and estrogen receptor alpha in the mouse vagina exposed neonatally to diethylstilbestrol

Growth factors and estrogen receptor (ER) signaling cooperate to play essential roles in cell proliferation, differentiation and tumor progression in mouse reproductive organs. Treatment of neonatal mice with diethylstilbestrol (DES) induces an estrogen-independent persistent proliferation and cornification of the vaginal epithelium, which results in cancerous lesions later in life. However, the mechanisms of the estrogen-dependent and -independent pathways essentially remain unknown. We characterized the expression of epidermal growth factor (EGF)-like growth factors (EGF, transforming growth factor alpha (TGF-alpha), heparin-binding EGF-like growth factor (HB-EGF), betacellulin (BTC), amphiregulin (APR), epiregulin (EPR) and neuregulin (NRG) 1) and erbB receptors (EGF receptor (EGFR), erbB2/neu, erbB3 and erbB4) in the vaginae of mice treated either neonatally (0-4 day) or as adults (55-59 day) with estrogens. EGFR and erbB2 were activated in the vaginal epithelium of mice by estrogen treatment. This activation was also encountered in vaginae from neonatally DES-exposed mice, along with the expression of EGF, TGF-alpha, HB-EGF, BTC, APR, EPR and NRG1. Immunohistochemical analysis indicated that erbB2 was primarily expressed in vaginal epithelium. Finally, we found that serine 118 and 167 located in the AF-1 domain of ERalpha were phosphorylated in these vaginae. AG825, AG1478 or ICI 182,780 administration blocked proliferation of vaginal epithelium induced by neonatal DES exposure. Thus, signal transduction via EGFR and erbB2 could be related to the estrogen-induced vaginal changes and persistent erbBs phosphorylation and sustained expression of EGF-like growth factors, leading to ERalpha activation that may result in cancerous lesions in vaginae from neonatally DES-exposed mice later in life.     

Blinded, randomized, multicenter study to evaluate single administration pegfilgrastim once per cycle versus daily filgrastim as an adjunct to chemotherapy in patients with high-risk stage II or stage III/IV breast cancer.

PURPOSE: This multicenter, randomized, double-blind, active-control study was designed to determine whether a single subcutaneous injection of pegfilgrastim (SD/01, sustained-duration filgrastim; 100 microg/kg) is as safe and effective as daily filgrastim (5 microg/kg/d) for reducing neutropenia in patients who received four cycles of myelosuppressive chemotherapy. PATIENTS AND METHODS: Sixty-two centers enrolled 310 patients who received chemotherapy with docetaxel 75 mg/m(2) and doxorubicin 60 mg/m(2) on day 1 of each cycle for a maximum of four cycles. Patients were randomized to receive on day 2 either a single subcutaneous injection of pegfilgrastim 100 microg/kg per chemotherapy cycle (154 patients) or daily subcutaneous injections of filgrastim 5 microg/kg/d (156 patients). Absolute neutrophil count (ANC), duration of grade 4 neutropenia, and safety parameters were monitored. RESULTS: One dose of pegfilgrastim per chemotherapy cycle was comparable to daily subcutaneous injections of filgrastim with regard to all efficacy end points, including the duration of severe neutropenia and the depth of ANC nadir in all cycles. Febrile neutropenia across all cycles occurred less often in patients who received pegfilgrastim. The difference in the mean duration of severe neutropenia between the pegfilgrastim and filgrastim treatment groups was less than 1 day. Pegfilgrastim was safe and well tolerated, and it was similar to filgrastim. Adverse event profiles in the pegfilgrastim and filgrastim groups were similar. CONCLUSION: A single injection of pegfilgrastim 100 microg/kg per cycle was as safe and effective as daily injections of filgrastim 5 microg/kg/d in reducing neutropenia and its complications in patients who received four cycles of doxorubicin 60 mg/m(2) and docetaxel 75 mg/m(2).     

Optimization of boron neutron capture therapy for the treatment of undifferentiated thyroid cancer

PURPOSE: To analyze the possible increase in efficacy of boron neutron capture therapy (BNCT) for undifferentiated thyroid carcinoma (UTC) by using p-boronophenylalanine (BPA) plus 2,4-bis (alpha,beta-dihydroxyethyl)-deutero-porphyrin IX (BOPP) and BPA plus nicotinamide (NA) as a radiosensitizer of the BNCT reaction. METHODS AND MATERIALS: Nude mice were transplanted with a human UTC cell line (ARO), and after 15 days they were treated as follows: (1) control, (2) NCT (neutrons alone), (3) NCT plus NA (100 mg/kg body weight [bw]/day for 3 days), (4) BPA (350 mg/kg bw) + neutrons, (5) BPA + NA + neutrons, and (6) BPA + BOPP (60 mg/kg bw) + neutrons. The flux of the mixed (thermal + epithermal) neutron beam was 2.8 x 10(8) n/cm(2)/sec for 83.4 min. RESULTS: Neutrons alone or with NA caused some tumor growth delay, whereas in the BPA, BPA + NA, and BPA + BOPP groups a 100% halt of tumor growth was observed in all mice at 26 days after irradiation. When the initial tumor volume was 50 mm(3) or less, complete remission was found with BPA + NA (2 of 2 mice), BPA (1 of 4), and BPA + BOPP (7 of 7). After 90 days of complete regression, recurrence of the tumor was observed in BPA + NA (2 of 2) and BPA + BOPP (1 of 7). The determination of apoptosis in tumor samples by measurements of caspase-3 activity showed an increase in the BNCT (BPA + NA) group at 24 h (p < 0.05 vs. controls) and after the first week after irradiation in the three BNCT groups. Terminal transferase dUTP nick end labeling analysis confirmed these results. CONCLUSIONS: Although NA combined with BPA showed an increase of apoptosis at early times, only the group irradiated after the combined administration of BPA and BOPP showed a significantly improved therapeutic response.     

ERβ-specific agonists and genistein inhibit proliferation and induce apoptosis in the large and small intestine

Epidemiological data indicate that intake of estrogens and isoflavones may be beneficial for the prevention of colorectal cancer (CRC). Based on this data, the aim of the study was to investigate estrogen receptor (ER) subtype-specific effects on intestinal homeostasis. Ovariectomized (OVX) female Wistar rats were either treated with 17β-estradiol (4 μg/kg body wt/day) (E2), an ERα-specific agonist (ALPHA) (10 μg/kg body wt/day), an ERβ-specific agonist (BETA) (100 μg/kg body wt/day) or genistein (GEN) (10 mg/kg body wt/day) for three weeks. Vehicle-treated OVX and SHAM animals and those cotreated with BETA and the pure antiestrogen Fulvestrant (ICI 182780) (100 μg/kg body wt/day and 3 mg/kg body wt/day) served as controls. GEN and BETA treatment but not E2 and ALPHA administration reduced proliferation in ileal and colonic mucosa cells. The rate of apoptosis in the small intestine and colon was increased by treatment with BETA and GEN, but not by E2. BETA induced antiproliferative and proapoptotic activity also in SHAM animals. The effects were antagonized by the pure antiestrogen Fulvestrant. Polymerase chain reaction gene array analysis revealed that BETA resulted in the downregulation of the oncogene transformation-related protein 63 (p63). Our data indicate that activation of the ERβ by specific ERβ agonists and GEN induces antiproliferative and proapoptotic effects in the intestinal tract. This observation can be taken as an indication that intake of GEN and specific ERβ agonists may protect the ileal and colonic epithelium from tumor development via modulation of tissue homeostasis.     

Delivery of (10)boron to oral squamous cell carcinoma using boronophenylalanine and borocaptate sodium for boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a unique radiation therapy in which boron compounds are trapped into tumor cells. To determine the biodistribution of boronophenylalanine (BPA) in nude mice carrying oral squamous cell carcinoma (SCC), BPA was administered at a dose of 250 mg/kg body weight intraperitoneally. Two hours later, (10)B concentration in the tumor was 15.96 ppm and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 6.44, 4.19, 4.68 and 4.56, respectively. Two hours after the administration of borocaptate sodium (BSH) at a dose of 75 mg/kg body weight, (10)B concentration in the tumor was 3.61 ppm, and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 0.77, 1.05, 0.60 and 0.59, respectively. When cultured oral SCC cells were incubated with BPA or BSH for 2 h and then exposed to thermal neutrons, the proportion of survival cells that were capable of forming cell colonies decreased exponentially, depending on (10)B concentration. BPA-mediated BNCT was more efficient than BSH-mediated BNCT. Addition of boron compounds in the cell suspension during neutron irradiation enhanced the cell-killing effect of the neutrons. These results indicate that BPA is more selectively incorporated into human oral SCC as compared with normal oral tissues, and that both extra- and intra-cellular BPA contribute to the cell-killing effect of BNCT. BPA may be a useful boron carrier for BNCT in the treatment of advanced oral SCC.     

Maternal Resveratrol Treatment Reduces the Risk of Mammary Carcinogenesis in Female Offspring Prenatally Exposure to 2,3,7,8-Tetrachlorodibenzo-p-Dioxin

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) presents adverse effects on breast development/carcinogenesis. This study aimed to identify the ability of resveratrol (Res) to modify the adverse effects of TCDD in a female offspring. Pregnant female Wistar rats were allocated into four groups: TCDD, TCDD + Res, Res, and control. TCDD (1 μg/kg) was orally administered as a single dose on gestational day (GD) 15, and Res was orally administered during GD10–21 and lactation at a dose of 20 mg/kg/day. Female offsprings were euthanized on a specific postnatal day (PND) for hormonal analysis (PND 22, 48–51), vaginal opening (PND 30–48), and mammary gland morphology (PND 22). Other females received two doses of N-nitroso-N-methylurea (MNU, 50 mg/kg) on PNDs 22 and 51 and were euthanized on PND 24 (Ki-67, ER-α and apoptosis indexes or molecular analysis) or PND 180 (tumor assay). TCDD exposure altered the development of the mammary structure while these alterations were partially improved by maternal Res. Two days after first MNU administration, some genes associated with apoptosis were altered in the mammary tissue from the TCDD group (Bax and Caspase 3 down- and Bcl-2 upregulated) but were also partially reestablished by maternal Res. Mammary gland bcl-2 and bcl-xl proteins expression was increased while the apoptosis index was reduced by TCDD exposure but restored by maternal Res. An increase in number of mammary tumors was observed in female offspring from the TCDD group compared to the other groups. The results indicate that most mammary changes induced in female offspring through TCDD exposure or after MNU administrations were reduced by maternal resveratrol treatment.     

Renal damage in mice after treatment with cisplatin and x-rays: comparison of fractionated and single-dose studies

Functional kidney damage in mice was measured after bilateral irradiation with x-rays alone or in combination with cisplatin (c-DDP). A single drug dose (6 mg/kg) was injected 30 minutes before the first of four or eight x-ray doses, given as four fractions per day with a minimum interval of 5 hours between treatments. A 30-fraction schedule was also investigated, with 15 fractions given in the first week (3 fractions per day), followed by a 2-week rest period and another 15 fractions in the fourth week. The c-DDP (4 mg/kg) was administered 30 minutes before the first fraction of each week, giving a total drug dose of 8 mg/kg. Renal function was assessed monthly from 10 to 37 weeks after the start of treatment by the clearance of 51Cr-labeled EDTA. The combined treatment caused more kidney damage than either agent alone for all fractionation schedules. Enhancement of the radiation damage by c-DDP changed only slightly with fractionation; dose enhancement factors were 1.2 for 1 fraction to 1.3 for 30 fractions. Modeling studies showed that this was consistent with the additive toxic effects of the two agents. There was no change in the alpha/beta for renal damage after x-rays plus c-DDP, compared with x-rays alone (alpha/beta = 1.9 Gy), implying that there was no reduction in repair and no modification of the x-ray response by c-DDP.