Conjugated Linoleic Acid Isomers Affect Profile of Lipid Compounds and Intensity of Their Oxidation in Heart of Rats with Chemically-Induced Mammary Tumors-Preliminary Study.

Breast cancer and cardiovascular diseases (CVD) have shared risk factors and mechanisms of pathogenicity, as proven by increased cardiac risk in breast cancer patients receiving anticancerogenic therapies and in cancer survivors. A growing mammary tumor may cause heart injury in cancer patients who have not yet been treated. This study aimed to evaluate the effect of conjugated linoleic acid (CLA) supplementation of female rats with 7,12-dimethylbenz(a)anthracene (DMBA)-induced cancerogenesis on fatty acids (FAs), conjugated FAs (CFAs), malondialdehyde (MDA), cholesterol and oxysterols content in cardiac tissue. FAs, cholesterol and oxysterols contents were determined by gas chromatography coupled with mass spectrometry, while the contents of CFAs and MDA were determined by high performance liquid chromatography with photodiode detection. Our results indicate that both CLA supplementation and the presence of tumors influence the lipid biomarkers of CVD. A significant interaction of both experimental factors was observed in the content of polyunsaturated FAs (PUFAs), n-6 PUFAs and CFAs. CLA supplementation significantly inhibited PUFA oxidation, as evidenced by the lower content of MDA in rats' hearts, while the cancerous process intensified the oxidation of cholesterol, as confirmed by the elevated levels of 7-ketocholesterol in DMBA-treated rats. These results may significantly expand knowledge about CLA properties in terms of the prevention of co-existing non-communicable diseases.

The protective effects of paeonol against epirubicin-induced hepatotoxicity in 4T1-tumor bearing mice via inhibition of the PI3K/Akt/NF-kB pathway.

Epirubicin is widely used for the treatment of various breast cancers; however, it has serious adverse side effects, such as hepatotoxicity, which require dose-adjustment or therapy substitution. Paeonol, an active component from Moutan Cortex, has a variety of biological activities, including preventing or reducing various toxicities induced by antineoplastics. Protection by paeonol against hepatotoxicity induced by epirubicin and the underlying mechanism of action were investigated in this study. Cytosolic enzymes in the serum and oxidative stress indices in the liver were determined. The protective effects were determined using the MTT assay in vitro or by evaluating the expression of apoptotic factors and crucial proteins in the PI3K/Akt/NF-kB pathway using western blot analysis. It is concluded that paeonol alleviates epirubicin-induced hepatotoxicity in 4T1-tumor bearing mice by inhibiting the PI3K/Akt/NF-kB pathway.

Paternal nutrition and cancer programming: the influence of selenium deficiency or supplementation on the susceptibility of female offspring to chemically-induced mammary carcinogenesis / Nutrição paterna e programação do câncer: influência da deficiência ou suplementação com selênio na susceptibilidade da prole feminina à carcinogênese mamária quimicamente induzida

Breast cancer is an important public health problem. As mammary gland development is a dynamic process that initiates in embryonic life, recent evidence show that in-utero life exposure to maternal nutritional factors can alter mammary gland development and program breast cancer risk in adult life. Even tough studies focus on maternal nutrition, recent evidence show that paternal nutritional factors in-utero and during preconception also affects their female offspring mammary gland development and breast cancer susceptibility in adult life. Studies highlight epigenetic modulation of gene expression in the mammary gland as possible breast cancer programming underlying mechanisms. Selenium is a micronutrient with essential role in central aspects of embryogenesis, male fertility and that has been extensively studied as a chemopreventive agent in several breast cancer models. Among selenium possible mechanisms of action, modulation of cell proliferation, apoptosis, DNA damage, gene expression and epigenetic marks are highlighted. Thus, a rat experiment was conducted to evaluate whether paternal selenium deficiency or supplementation during preconception could affect mammary gland development and breast cancer risk, as well as possible molecular mechanisms involved. Four-week old male Sprague-Dawley rats were exposed to experimental diets (AIN93G) containing 0.15 (control), 0.05 (deficient) and 1ppm (supplemented) of selenium as sodium selenate for 9 weeks and mated with control females. At 7-week old, mammary carcinogenesis was induced in their female offspring by oral administration of 7,12 dymethylbenz[a] anthracene and mammary neoplasia development was evaluated. Paternal selenium deficiency during preconception altered mammary gland development as increased terminal end buds (TEBs) number, epithelial elongation and cell proliferation and decreased apoptosis that were associated with increased breast cancer risk (higher incidence and grade tumors). In addition, paternal selenium deficiency during preconception induced molecular alterations in the mammary gland of the female offspring such as global DNA hypomethylation, increased global levels of H3K27me3 and altered expression of genes related to early life and mammary gland development, apoptosis, cell cycle control, and DNA damage repair. Paternal selenium supplementation during preconception on the other hand did not influence breast cancer programing. Our data show that breast cancer risk can be determined in early-life stages trough the male germline molecular modulation and preconception as an important window of opportunity to start breast cancer prevention strategies. Assuring and adequate selenium intake by men could be a possible starting point

O câncer de mama é um importante problema de saúde pública. O desenvolvimento da glândula mamária é um processo dinâmico que se inicia na vida intrauterina e evidências recentes mostram que a exposição do feto a fatores nutricionais maternos altera o desenvolvimento da glândula mamária e a susceptibilidade ao câncer de mama na vida adulta. Mesmo com um maior foco na nutrição materna, evidências recentes apontam que a nutrição paterna no período intrauterino e de preconcepção também afetam o desenvolvimento da glândula mamária e o risco de câncer de mama da sua prole feminina na vida adulta. Estudos apontam a modulação epigenética da expressão de genes na glândula mamária como possíveis mecanismos envolvidos na programação do câncer de mama. O selênio é um micronutriente com papel essencial em aspectos centrais da embriogênese, fertilidade masculina e que tem sido extensivamente estudado como um agente quimiopreventivo em diferentes modelos de câncer de mama. Dentre os possíveis mecanismos de ação do selênio, destacam-se a capacidade de modulação da proliferação celular, apoptose, danos do DNA e da expressão de genes e mecanismos epigenéticos. Dessa forma, foi conduzido um experimento em ratos para avaliar se a deficiência ou suplementação paterna com selênio durante o período de preconcepção poderia afetar na prole feminina o desenvolvimento da glândula mamária e o risco ao câncer de mama na vida adulta, assim como possíveis mecanismos moleculares envolvidos. Ratos machos da linhagem Sprague-Dawley com 4 semanas de vida foram submetidos à dieta experimental AIN93G contendo 0,15 (controle); 0,05 (deficiente) e 1ppm (suplementada) com selênio na forma de selenato de sódio por 9 semanas e acasalados com fêmeas controle. Com 7 semanas de vida, a carcinogênese mamária foi iniciada na prole feminina através da administração oral do carcinógeno químico 7,12 dimetilbenz[a] antraceno e o desenvolvimento das neoplasias mamárias foi avaliado. A deficiência paterna de selênio causou alterações no desenvolvimento da glândula mamária da prole feminina como aumento no número de terminal end buds (TEBs), aumento da elongação do epitélio mamário, aumento da proliferação celular e diminuição da apoptose que foram associados ao aumento do risco do câncer de mama (maior incidência e agressividade das lesões). Além disso, a deficiência paterna de selênio causou alterações de nível molecular na glândula mamária da prole feminina como hipometilação global, aumento dos níveis globais de H3K27me3 e alteração na expressão de genes relacionados ao desenvolvimento no início da vida e da glândula mamária, apoptose, controle de ciclo celular e reparo de danos no DNA. A suplementação paterna com selênio não foi influenciou o desenvolvimento da glândula mamária e o risco ao câncer de mama na vida adulta. Nossos resultados mostram que o risco do câncer de mama pode ser determinado no início da vida através de influências paternas por meio da modulação de mecanismos moleculares e que o período de preconcepção se caracteriza como uma importante janela de susceptibilidade para iniciar estratégias de diminuição do risco do câncer de mama. Assegurar uma ingestão adequada de selênio por homens pode ser um possível ponto de partida

The combined use of Camellia sinensis and metronomic zoledronate in 4T1 mouse carcinoma against tumor growth and metastasis.

In previous studies, we demonstrated that the green tea Camellia sinensis (CS) water extract had potent antitumor and antimetastatic effects on 4T1 breast cancer. The metronomic regimen (0.0125 mg/kg twice a week for 4 weeks) of zoledronate (ZOL) was found to be effective in decreasing tumor burden and metastasis as compared with conventional regimen. The aim of the present study was to investigate the antitumor, antimetastatic and anti-osteolytic effects of the combined use of CS water extract and metronomic ZOL against 4T1 breast carcinoma in vitro and in vivo. The results demonstrated that the combination of CS+ZOL exerted a more potent effect on lung and liver by decreasing tumor burden and metastasis, when compared to CS or metronomic ZOL as monotherapies. The combination of CS+ZOL demonstrated optimal bone protection against breast cancer-induced osteolysis for the three groups of CS, ZOL and CS+ZOL. The in vitro results further demonstrated that ZOL enhanced CS-induced apoptosis in 4T1 cells as assessed by the Annexin V-FITC/PI staining and caspase-3 activity assays. In addition, the combined use of CS+ZOL significantly inhibited 4T1 cell migration. Mechanistic studies showed that the enzyme levels of matrix metalloproteinases (MMP)-2 and MMP-9 were suppressed significantly by CS+ZOL. In conclusion, to the best of our knowledge, this is the first study to investigate the novel combined application of herbal extract CS and chemotherapy ZOL in 4T1 breast cancer. The combination of CS plus metronomic ZOL demonstrated significant antitumor, antimetastatic and anti-osteolytic effects against breast cancer, and suggested potential clinical application for breast cancer patients.

Omega-3 fatty acids reduce obesity-induced tumor progression independent of GPR120 in a mouse model of postmenopausal breast cancer.

Obesity and inflammation are both risk factors for a variety of cancers, including breast cancer in postmenopausal women. Intake of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) decreases the risk of breast cancer, and also reduces obesity-associated inflammation and insulin resistance, but whether the two effects are related is currently unknown. We tested this hypothesis in a postmenopausal breast cancer model using ovariectomized, immune-competent female mice orthotopically injected with Py230 mammary tumor cells. Obesity, whether triggered genetically or by high-fat diet (HFD) feeding, increased inflammation in the mammary fat pad and promoted mammary tumorigenesis. The presence of tumor cells in the mammary fat pad further enhanced the local inflammatory milieu. Tumor necrosis factor-alpha (TNF-α) was the most highly upregulated cytokine in the obese mammary fat pad, and we observed that TNF-α dose-dependently stimulated Py230 cell growth in vitro. An ω-3 PUFA-enriched HFD (referred to as fish oil diet, FOD) reduced inflammation in the obese mammary fat pad in the absence of tumor cells and inhibited Py230 tumor growth in vivo. Although some anti-inflammatory effects of ω-3 PUFAs were previously shown to be mediated by the G-protein-coupled receptor 120 (GPR120), the FOD reduced Py230 tumor burden in GPR120-deficient mice to a similar degree as observed in wild-type mice, indicating that the effect of FOD to reduce tumor growth does not require GPR120 in the host mouse. Instead, in vitro studies demonstrated that ω-3 PUFAs act directly on tumor cells to activate c-Jun N-terminal kinase, inhibit proliferation and induce apoptosis. Our results show that obesity promotes mammary tumor progression in this model of postmenopausal breast cancer and that ω-3 PUFAs, independent of GPR120, inhibit mammary tumor progression in obese mice.

Proline/arginine-rich end leucine-rich repeat protein N-terminus is a novel osteoclast antagonist that counteracts bone loss.

(hbd) PRELP is a peptide corresponding to the N-terminal heparin binding domain of the matrix protein proline/arginine-rich end leucine-rich repeat protein (PRELP). (hbd) PRELP inhibits osteoclastogenesis entering pre-fusion osteoclasts through a chondroitin sulfate- and annexin 2-dependent mechanism and reducing the nuclear factor-κB transcription factor activity. In this work, we hypothesized that (hbd) PRELP could have a pharmacological relevance, counteracting bone loss in a variety of in vivo models of bone diseases induced by exacerbated osteoclast activity. In healthy mice, we demonstrated that the peptide targeted the bone and increased trabecular bone mass over basal level. In mice treated with retinoic acid to induce an acute increase of osteoclast formation, the peptide consistently antagonized osteoclastogenesis and prevented the increase of the serum levels of the osteoclast-specific marker tartrate-resistant acid phosphatase. In ovariectomized mice, in which osteoclast activity was chronically enhanced by estrogen deficiency, (hbd) PRELP counteracted exacerbated osteoclast activity and bone loss. In mice carrying osteolytic bone metastases, in which osteoclastogenesis and bone resorption were enhanced by tumor cell-derived factors, (hbd) PRELP reduced the incidence of osteolytic lesions, both preventively and curatively, with mechanisms involving impaired tumor cell homing to bone and tumor growth in the bone microenvironment. Interestingly, in tumor-bearing mice, (hbd) PRELP also inhibited breast tumor growth in orthotopic sites and development of metastatic disease in visceral organs, reducing cachexia and improving survival especially when administered preventively. (hbd) PRELP was retained in the tumor tissue and appeared to affect tumor growth by interacting with the microenvironment rather than by directly affecting the tumor cells. Because safety studies and high-dose treatments revealed no adverse effects, (hbd) PRELP could be employed as a novel biological agent to combat experimentally induced bone loss and breast cancer metastases, with a potential translational impact.

Dehydroepiandrosterone intake protects against 7,12-dimethylbenz(a)anthracene-induced mammary tumor development in the obese Zucker rat model.

Obesity has been epidemic in the US for over two decades; almost 65% of adults in the US are overweight. Obesity has been linked with the risk of development of various cancers, including breast cancer. Dehydroepiandrosterone (DHEA) is an over-the-counter dietary supplement used as an immunomodulating, anti-depressant, anti-aging, anti-cardiovascular disease, and anti-cancer agent and anti-obesity supplement. The objectives of this study were to investigate the long-term effects of obesity and DHEA treatment on body weight gain and on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumor development. Forty-three six-week-old obese female Zucker rats were used. Rats were randomly assigned and had ad libitum access to water and a diet of either chow (2016) as a control diet or chow with the addition of DHEA at a concentration of 6 g/kg of chow as a DHEA diet. All rats were orally gavaged at age 50 days with 65 mg DMBA/kg body weight. Rats were weighed and palpated twice weekly for detection of mammary tumors and sacrificed 155 days post-DMBA treatment. Obese rats fed the DHEA diet gained significantly less weight than obese control diet rats (P<0.001). At the end of the experiment, 55% of the control diet group developed mammary tumors, while no tumors were detected in the DHEA diet group (P<0.001). Our results suggest that DHEA treatment can reduce body weight gain and protects against DMBA-induced mammary tumor development in the obese Zucker rat model.

Bone resorption increases tumour growth in a mouse model of osteosclerotic breast cancer metastasis.

Osteosclerotic metastases account for 20% of breast cancer metastases with the remainder osteolytic or mixed. In mouse models, osteolytic metastases are dependent on bone resorption for their growth. However, whether the growth of osteosclerotic bone metastases depends on osteoclast or osteoblast actions is uncertain. In this study, we investigate the effects of high and low bone resorption on tumour growth in a mouse model of osteosclerotic metastasis. We implanted human breast cancer, MCF-7, cells into the tibiae of mice. Low and high levels of bone resorption were induced by osteoprotegerin (OPG) treatment or calcium deficient diet respectively. We demonstrate that OPG treatment significantly reduces tumour area compared to vehicle (0.42 +/- 0.06 vs. 1.27 +/- 0.16 mm2, P < 0.01) in association with complete inhibition of osteoclast differentiation. In contrast, low calcium diet increases tumour area compared to normal diet (0.90 +/- 0.30 vs. 0.58 +/- 0.20 mm2, P < 0.05) in association with increased osteoclast numbers (84.44 +/- 5.18 vs. 71.11 +/- 3.56 per mm2 bone lesion area, P < 0.05). Osteoblast surfaces and new woven bone formation were similarly increased within the tumour boundaries in all treatment groups. Tumour growth in this model of osteosclerotic metastasis is dependent on ongoing bone resorption, as has been observed in osteolytic models. Bone resorption, rather than bone formation, apparently mediates this effect as osteoblast surfaces in the tumour mass were unchanged by treatments. Treatment of breast cancer patients through correction of calcium deficiency and/or with anti-resorptive agents such as OPG, may improve patient outcomes in the adjuvant as well as palliative settings.

Nutritional folate status influences the efficacy and toxicity of chemotherapy in rats.

The effect of folate status on the efficacy and toxicity of chemotherapy was investigated in weanling Fischer 344 rats maintained on diets of varying folate content or supplemented with daily injections of folic acid, 50 mg/kg, for 6 to 7 weeks. MADB106 rat mammary tumor growth rate was the same in folate replete and supplemented rats, but retarded in the low folate groups. The tumor growth inhibitions in low folate, replete and high folate rats treated with cyclophosphamide were: 53%, 98%, and 97% (P = .048); with 5-fluorouracil (5-FU): 46%, 49%, and 66%; and with doxorubicin: 25%, 55%, and 61%. Significant differences in survival were observed for cyclophosphamide (P = .0084) and 5-FU (P = .025) related to dietary folate content. Thus, folate deficiency impedes tumor growth rate, but supplementation does not accelerate it in folate replete animals. Correction of folate deficiency approximately doubles the efficacy of cyclophosphamide in rats with much less host toxicity. Folate repletion improves survival in 5-FU-treated animals. These studies indicate that nutritional folate status has an important influence on the efficacy and toxicity of some commonly used cancer chemotherapeutic drugs.

Effect of growth hormone and protein intake on tumor growth and host cachexia.

BACKGROUND: Growth hormone supplementation has been shown to stimulate muscle protein synthesis and to improve nitrogen balance in a variety of catabolic states. The role of growth hormone to support the tumor-bearing host is complicated by the risk that growth hormone or its intermediaries may stimulate tumor growth. The purpose of this study is to examine the effect of growth hormone supplementation in tumor-bearing rats. This is studied in the protein-fed and protein-starved state in an attempt to isolate a selective benefit for the host over the tumor. METHODS: Forty Lewis rats bearing a metastatic mammary adenocarcinoma (MAC-33) were divided into four groups: one receiving a regular diet plus saline solution, one receiving a regular diet plus growth hormone (1 IU/kg/day), one receiving protein-depleted diet plus saline solution, and one receiving a protein-depleted diet plus growth hormone. After 25 days of growth hormone treatment, animals were killed to determine primary tumor size, tumor/carcass ratio, host organ composition, pulmonary metastasis, and serum amino acid levels. RESULTS: The tumor/carcass ratio was decreased as a result of growth hormone treatment in both the protein-fed and protein-starved groups. Growth hormone supplementation resulted in increased carcass weight, muscle weight, and muscle protein content in the protein-fed, tumor-bearing animals (p < 0.05). In the protein-starved, tumor-bearing rats growth hormone supplementation resulted in a significant decrease in tumor volume and tumor protein content. Amino acid analysis suggests that the amino acid tyrosine is a rate-limiting substrate for tumor cell proliferation in this model. CONCLUSIONS: Growth hormone has a differential effect on tumor and host growth in the protein-fed and protein-starved state. Growth hormone supplementation inhibited tumor growth in protein-deprived animals. This is most likely accomplished indirectly by limiting amino acid substrate availability to the tumor.

1 alpha-hydroxyvitamin D3, hypercalcemia, and growth suppression of 7,12-dimethylbenz[a]anthracene-induced rat mammary tumors.

1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] was administered to female Sprague-Dawley rats with 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors. 1 alpha(OH)D3 suppressed the growth of the rat mammary tumors dose-dependently, and in the high dose groups treated with 0.5-1.0 micrograms/kg of 1 alpha(OH)D3, significant inhibition of tumor growth was observed. But daily oral administration of 1 alpha(OH)D3 for four consecutive weeks caused side effects such as hypercalcemia and weight loss. We compared 0.5 microgram/kg of 1 alpha(OH)D3 three times weekly with the same dose six times weekly to discover whether or not the side effects can be reduced by treatment schedule. Both groups showed a significant oncostatic effect, compared with the control group, while the side effects were relieved in the three times weekly group. Regarding estrogen receptors (ER) in the tumors, there was no significant difference among the groups. These results suggested that the antitumor effect of 1 alpha(OH)D3 on DMBA-induced mammary tumors was not related to ER status. Combined use of 1 alpha(OH)D3 with 5-fluorouracil (5-FU) or medroxyprogesterone acetate (MPA) was also examined. No significant augmentation of the antitumor effect was seen in the two combinations, although the combined therapy with MPA showed a significant inhibition of weight loss in the rats.

Effect of anemia on tumor radiosensitivity under normo and hyperbaric conditions.

The effect of chronic anemia on tumor radiosensitivity in a murine tumor has been investigated. Anemia was induced by bilateral kidney irradiation given several months before tumor implantation. Anemic, anemic transfused, and normal non-anemic age-matched tumor bearing animals were irradiated with X rays (2 F/24 hr) either in air, air plus misonidazole, or under hyperbaric oxygen. The most resistant response was that of tumors grown in normal mice treated in air. Anemia produced an increase in radiosensitivity which was further enhanced by red blood cell replacement. The most sensitive overall response was seen in the anemic-transfused group treated with HBO.