RESUMEN
Retinal degeneration is a collection of devastating conditions with progressive loss of vision which often lead to blindness. Research on retinal microglial cells offers great therapeutic potential in deterring the progression of degeneration. This study explored the mechanisms underlying the TREM2-mediated protective function of activated microglial cells during retinal degeneration. N-methyl-N-nitrosourea (MNU)-induced retinal degeneration was established in C57BL/6 J (WT) and Trem2 knockout (Trem2-/-) mice. We discovered that MNU treatment led to the concurrent processes of photoreceptor apoptosis and microglia infiltration. A significant upregulation of disease-associated microglia signature genes was observed during photoreceptor degeneration. Following MNU treatment, Trem2-/- mice showed exacerbated photoreceptor cell death, decreased microglia migration and phagocytosis, reduced microglial PPARγ activation and CD36 expression. Pharmaceutical activation of PPARγ promoted microglial migration, ameliorated photoreceptor degeneration and restored CD36 expression in MNU-treated Trem2-/- mice. Inhibition of CD36 activity worsened photoreceptor degeneration in MNU-treated WT mice. Our findings suggested that the protective effect of microglia during retinal degeneration was dependent on Trem2 expression and carried out via the activation of PPARγ and the consequent upregulation of CD36 expression. Our study linked TREM2 signaling with PPARγ activation, and provided a potential therapeutic target for the management of retinal degeneration.
Asunto(s)
Antígenos CD36 , Glicoproteínas de Membrana , Microglía , PPAR gamma , Receptores Inmunológicos , Degeneración Retiniana , Animales , Ratones , Apoptosis/efectos de los fármacos , Antígenos CD36/metabolismo , Antígenos CD36/genética , Movimiento Celular , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/genética , Metilnitrosourea/toxicidad , Ratones Endogámicos C57BL , Ratones Noqueados , Microglía/metabolismo , Microglía/patología , Fagocitosis , Células Fotorreceptoras/metabolismo , Células Fotorreceptoras/patología , PPAR gamma/metabolismo , Receptores Inmunológicos/metabolismo , Receptores Inmunológicos/genética , Degeneración Retiniana/patología , Degeneración Retiniana/metabolismoRESUMEN
Generation of O6-methylguanine (O6-meG) by DNA-alkylating agents such as N-methyl N-nitrosourea (MNU) activates the multiprotein mismatch repair (MMR) complex and the checkpoint response involving ATR/CHK1 and ATM/CHK2 kinases, which may in turn trigger cell cycle arrest and apoptosis. The Bloom syndrome DNA helicase BLM interacts with the MMR complex, suggesting functional relevance to repair and checkpoint responses. We observed a strong interaction of BLM with MMR proteins in HeLa cells upon treatment with MNU as evidenced by co-immunoprecipitation as well as colocalization in the nucleus as revealed by dual immunofluorescence staining. Knockout of BLM sensitized HeLa MR cells to MNU-induced cell cycle disruption and enhanced expression of the apoptosis markers cleaved caspase-9 and PARP1. MNU-treated BLM-deficient cells also exhibited a greater number of 53BP1 foci and greater phosphorylation levels of H2AX at S139 and RPA32 at S8, indicating the accumulation of DNA double-strand breaks. These findings suggest that BLM prevents double-strand DNA breaks during the MMR-dependent DNA damage response and mitigates O6-meG-induced apoptosis.
Asunto(s)
Apoptosis , Reparación de la Incompatibilidad de ADN , RecQ Helicasas , Humanos , RecQ Helicasas/metabolismo , RecQ Helicasas/genética , Células HeLa , Roturas del ADN de Doble Cadena , Metilnitrosourea/toxicidad , Síndrome de Bloom/genética , Síndrome de Bloom/metabolismo , Síndrome de Bloom/patología , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/genéticaRESUMEN
The incidence of breast cancer is increasing annually, making it a major health threat for women. Chemoprevention using natural, dietary, or synthetic products has emerged as a promising approach to address this growing burden. Atractylenolide-III (AT-III), a sesquiterpenoid present in various medicinal herbs, has demonstrated potential therapeutic effects against several diseases, including tumors, nonalcoholic fatty liver disease, and cerebral ischemic injury. However, its impact on breast cancer chemoprevention remains unexplored. In this study, we used an N-methyl-N-nitrosourea (NMU)-induced rat breast cancer model and 17ß-estradiol (E2)-treated MCF-10A cells to evaluate the chemopreventive potential of AT-III on mammary tumorigenesis. AT-III inhibited mammary tumor progression, evidenced by reduced tumor volume and multiplicity, prolonged tumor latency, and the reversal of NMU-induced weight loss. Furthermore, AT-III suppressed NMU-induced inflammation and oxidative stress through the Nrf2/ARE pathway in breast cancer tissues. In vitro, AT-III effectively suppressed E2-induced anchorage-independent growth and cell migration in MCF-10A cells. Nrf2 knockdown attenuated the protective effects of AT-III, highlighting the pivotal role of Nrf2 in AT-III-mediated suppression of tumorigenesis. The mechanism involves the induction of Nrf2 expression by AT-III through the autophagic degradation of Kelch-like ECH-associated protein 1 (Keap1). Overall, the results of this study indicate that AT-III is a promising candidate for breast cancer chemoprevention and provide valuable insights into its molecular interactions and signaling pathways.
Asunto(s)
Autofagia , Proteína 1 Asociada A ECH Tipo Kelch , Lactonas , Factor 2 Relacionado con NF-E2 , Sesquiterpenos , Transducción de Señal , Animales , Factor 2 Relacionado con NF-E2/metabolismo , Sesquiterpenos/farmacología , Femenino , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Lactonas/farmacología , Autofagia/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Ratas , Humanos , Línea Celular Tumoral , Ratas Sprague-Dawley , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Neoplasias Mamarias Experimentales/patología , Neoplasias Mamarias Experimentales/prevención & control , Neoplasias Mamarias Experimentales/inducido químicamente , Estrés Oxidativo/efectos de los fármacos , Metilnitrosourea/toxicidad , Carcinogénesis/efectos de los fármacos , Anticarcinógenos/farmacología , Estradiol/farmacologíaRESUMEN
BACKGROUND: Sn1-type alkylating agents methylate the oxygen atom on guanine bases thereby producing O6-methylguanine. This modified base could pair with thymine and cytosine, resulting in the formation of O6-methylguanine/thymine mismatch during DNA replication, recognized by the mismatch repair (MMR) complex, which then initiates the DNA damage response and subsequent apoptotic processes. In our investigation of the molecular mechanisms underlying MMR-dependent apoptosis, we observed FANCD2 modification upon the activity of alkylating agent N-methyl-N-nitrosourea (MNU). This observation led us to hypothesize a relevant role for FANCD2 in the apoptosis induction process. METHODS AND RESULTS: We generated FANCD2 knockout cells using the CRISPR/Cas9 method in the human cervical cancer cell line HeLa MR. FANCD2-deficient cells exhibited MNU hypersensitivity. Upon MNU exposure, FANCD2 colocalized with the MMR complex. MNU-treated FANCD2 knockout cells displayed severe S phase delay followed by increased G2/M arrest and MMR-dependent apoptotic cell death. Moreover, FANCD2 knockout cells exhibited impaired CtIP and RAD51 recruitment to the damaged chromatin and DNA double-strand break accumulation, indicated by simultaneously observed increased γH2AX signal and 53BP1 foci. CONCLUSIONS: Our data suggest that FANCD2 is crucial for recruiting homologous recombination factors to the sites of the MMR-dependent replication stress to resolve the arrested replication fork and counteract O6-methylguanine-triggered MMR-dependent apoptosis.
Asunto(s)
Apoptosis , Reparación de la Incompatibilidad de ADN , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi , Guanina , Humanos , Reparación de la Incompatibilidad de ADN/genética , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Apoptosis/genética , Apoptosis/efectos de los fármacos , Guanina/metabolismo , Guanina/análogos & derivados , Células HeLa , Daño del ADN , Metilnitrosourea/toxicidad , Sistemas CRISPR-Cas , Técnicas de Inactivación de Genes , Recombinasa Rad51/metabolismo , Recombinasa Rad51/genética , Replicación del ADN/efectos de los fármacos , Replicación del ADN/genéticaRESUMEN
Rev1 has two important functions in the translesion synthesis pathway, including dCMP transferase activity, and acts as a scaffolding protein for other polymerases involved in translesion synthesis. However, the role of Rev1 in mutagenesis and tumorigenesis in vivo remains unclear. We previously generated Rev1-overexpressing (Rev1-Tg) mice and reported that they exhibited a significantly increased incidence of intestinal adenoma and thymic lymphoma (TL) after N-methyl-N-nitrosourea (MNU) treatment. In this study, we investigated mutagenesis of MNU-induced TL tumorigenesis in wild-type (WT) and Rev1-Tg mice using diverse approaches, including whole-exome sequencing (WES). In Rev1-Tg TLs, the mutation frequency was higher than that in WT TL in most cases. However, no difference in the number of nonsynonymous mutations in the Catalogue of Somatic Mutations in Cancer (COSMIC) genes was observed, and mutations involved in Notch1 and MAPK signaling were similarly detected in both TLs. Mutational signature analysis of WT and Rev1-Tg TLs revealed cosine similarity with COSMIC mutational SBS5 (aging-related) and SBS11 (alkylation-related). Interestingly, the total number of mutations, but not the genotypes of WT and Rev1-Tg, was positively correlated with the relative contribution of SBS5 in individual TLs, suggesting that genetic instability could be accelerated in Rev1-Tg TLs. Finally, we demonstrated that preleukemic cells could be detected earlier in Rev1-Tg mice than in WT mice, following MNU treatment. In conclusion, Rev1 overexpression accelerates mutagenesis and increases the incidence of MNU-induced TL by shortening the latency period, which may be associated with more frequent DNA damage-induced genetic instability.
Asunto(s)
ADN Polimerasa Dirigida por ADN , Metilnitrosourea , Mutagénesis , Nucleotidiltransferasas , Neoplasias del Timo , Animales , Ratones , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Secuenciación del Exoma , Linfoma/genética , Linfoma/inducido químicamente , Linfoma/patología , Metilnitrosourea/toxicidad , Ratones Transgénicos , Mutación , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Neoplasias del Timo/genética , Neoplasias del Timo/inducido químicamente , Neoplasias del Timo/patologíaRESUMEN
YT521-B homology (YTH) domain family (YTHDF) proteins serve as readers that directly recognise m6A modifications. In this study, we aim to probe the role of YTHDF1 in environmental carcinogen-induced malignant transformation of gastric cells and gastric cancer (GC) carcinogenesis. We established a long-term low-dose MNU-induced malignant transformation model in gastric epithelial cells. In vivo and in vitro experiments were conducted to validate the malignant phenotype and characterise the roles of YTHDF1 and its downstream genes in malignant transformation cells. Additionally, we explored downstream m6A modification targets of YTHDF1 using RNA-sequencing, RNA immunoprecipitation, and proteomics analyses, and conducted validation experiments in cell experiments and clinical samples. Long-term low-dose exposure of MNU converted normal Gges-1 cells into malignant cells. YTHDF1 mRNA and protein expression are increased in MNU-induced malignant cells (p<0.001). Meanwhile, YTHDF1 knockdown inhibits the malignant potential of MNU-treated cells (p<0.01). YTHDF1 knockdown specifically suppresses HSPH1 protein, but not RNA levels. RIP-qPCR validates HSPH1 is the target of YTHDF1 (p<0.01). HSPH1 knockdown impairs the malignant potential of MNU-induced transformed cells. The increased expression of the key regulatory factor YTHDF1 in MNU-induced gastric carcinogenesis affects malignant transformation and tumorigenesis by regulating the translation of downstream HSPH1. These findings provide new potential targets for preventing and treating environmental chemical-induced gastric carcinogenesis.
Asunto(s)
Metilnitrosourea , Proteínas de Unión al ARN , Neoplasias Gástricas , Neoplasias Gástricas/patología , Neoplasias Gástricas/inducido químicamente , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/genética , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Humanos , Animales , Metilnitrosourea/toxicidad , Ratones , Carcinogénesis/inducido químicamente , Carcinogénesis/metabolismo , Carcinogénesis/patología , Carcinogénesis/genética , Transformación Celular Neoplásica/inducido químicamente , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/genética , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Biosíntesis de Proteínas/efectos de los fármacos , MasculinoRESUMEN
Animal models for retinal degeneration are essential for elucidating its pathogenesis and developing new therapeutic strategies in humans. N-methyl-N-nitrosourea (MNU) has been extensively used to construct a photoreceptor-specific degeneration model, which has served to unveil the molecular process of photoreceptor degeneration as well as the mechanisms regulating the protective responses of remaining cells. Methyl methanesulphonate (MMS), also known to cause photoreceptor degeneration, is considered a good alternative to MNU due to its higher usability; however, detailed pathophysiological processes after MMS treatment remain uncharacterized. Here, we analyzed the time course of photoreceptor degeneration, Müller glial proliferation, and expression of secretory factors after MNU and MMS treatments in rats. While the timing of rod degeneration was similar between the treatments, we unexpectedly found that cones survived slightly longer after MMS treatment. Müller glia reentered the cell cycle at a similar timing after the two treatments; however, the G1/S transition occurred earlier after MMS treatment. Moreover, growth factors such as FGF2 and LIF were more highly upregulated in the MMS model. These data suggest that comparative analyses of the two injury models may be beneficial for understanding the complex regulatory mechanisms underlying the proliferative response of Müller glia.
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Degeneración Retiniana , Humanos , Ratas , Animales , Degeneración Retiniana/inducido químicamente , Degeneración Retiniana/tratamiento farmacológico , Degeneración Retiniana/metabolismo , Alquilantes/toxicidad , Neuroglía/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Metilnitrosourea/toxicidad , Células Fotorreceptoras de Vertebrados/metabolismo , Modelos Animales de EnfermedadRESUMEN
In order to investigate the synergistic improving effect of lutein (LUT) and epigallocatechin-3-gallate (EGCG) treatment on retinitis pigmentosa (RP), an N-methyl-N-nitrosourea (MNU)-induced mouse model was conducted in the present study. Compared to the LUT alone treatment group, in the LUT combined with EGCG (LUT-EGCG) treatment group, the accumulation content of LUT was significantly increased by 50.24% in the liver. The morphological results indicated that LUT-EGCG treatment significantly improved the retina structure with the thickness of the outer nuclear layer restored to 185.28 ± 0.29 µm, showing no significant difference compared to the control group. The LUT-EGCG treatment also increased the production of short-chain fatty acids, such as acetic and propionic acids. Compared with the LUT alone treatment, the LUT-EGCG treatment significantly increased the relative abundance of Lachnospiraceae and Helicobacteraceae. RT-qPCR results indicated that LUT-EGCG treatment significantly increased the antiapoptotic gene Bcl-2 expression. In addition, the expression of IL-6 was significantly down-regulated in the LUT-EGCG group, while there was no significance in NF-κß, TNF-α, IL-1ß, and IL-18 compared with the LUT group. Correlation analysis supported the conclusion that LUT combined with EGCG may improve RP by modulating antiapoptotic gene expression and regulating the abundance of gut microbiota. However, the underlying mechanism still needs further research.
Asunto(s)
Catequina , Retinitis Pigmentosa , Ratones , Animales , Metilnitrosourea/toxicidad , Luteína , Retinitis Pigmentosa/tratamiento farmacológico , Retinitis Pigmentosa/genética , Retina , Catequina/farmacologíaRESUMEN
Vision loss and blindness are frequently caused by photoreceptor degeneration, for example in age-related macular degeneration and retinitis pigmentosa. However, there is no effective medicine to treat these photoreceptor degeneration-related diseases. Cell senescence is a common phenotype in many diseases; however, few studies have reported whether it occurs in photoreceptor degeneration diseases. Herein, we identified that cell senescence is associated with photoreceptor degeneration induced by N-methyl-N-nitrosourea (MNU, a commonly used photoreceptor degeneration model), presented as increased senescence-associated ß-galactosidase activity, DNA damage, oxidative stress and inflammation-related cytokine Interleukin 6 (IL6), and upregulation of cyclin p21 or p16. These results suggested that visual function might be protected using anti-aging treatment. Furthermore, Hyperoside is reported to help prevent aging in various organs. In this study, we showed that Hyperoside, delivered intravitreally, alleviated photoreceptor cell senescence and ameliorated the functional and morphological degeneration of the retina in vivo and in vitro. Importantly, Hyperoside attenuated the MNU-induced injury and aging of photoreceptors via AMPK-ULK1 signaling inhibition. Taken together, our results demonstrated that Hyperoside can prevent MNU-induced photoreceptor degeneration by inhibiting cell senescence via the AMPK-ULK1 pathway.
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Proteínas Quinasas Activadas por AMP , Degeneración Retiniana , Animales , Proteínas Quinasas Activadas por AMP/metabolismo , Apoptosis , Senescencia Celular , Modelos Animales de Enfermedad , Metilnitrosourea/toxicidad , Células Fotorreceptoras de Vertebrados/metabolismo , Retina/metabolismo , Degeneración Retiniana/inducido químicamente , Degeneración Retiniana/tratamiento farmacológico , Degeneración Retiniana/prevención & controlRESUMEN
Carcinogenicity tests predict the tumorigenic potential of various substances in the human body by studying tumor induction in experimental animals. There is a need for studies that explore the use of FVB/N-Trp53em2Hwl/Korl (FVB-Trp53+/-) mice, created by TALEN-mediated gene targeting in Korea, in carcinogenicity tests. This study was performed to determine whether FVB-Trp53+/- mice are a suitable model for short-term carcinogenicity studies. To compare the carcinogenicity at different concentrations, 25, 50, and 75 mg/kg of N-methyl-N-nitrosourea (MNU), a known carcinogen, were administered intraperitoneally to FVB-Trp53+/- and wild-type male mice. After 26 weeks, the survival rate was significantly reduced in FVB-Trp53+/- mice compared to the wild-type mice in the 50 and 75 mg/kg groups. The incidence of thymic malignant lymphoma (TML) in the 50 and 75 mg/kg groups was 54.2 and 59.1% in FVB-Trp53+/- male mice, respectively. TML metastasized to the lungs, spleen, lymph nodes, liver, kidney, and heart in FVB-Trp53+/- male mice. Furthermore, the incidence of primary lung tumors, such as adenomas and adenocarcinomas, was 65.4, 62.5, and 45.4% in the FVB-Trp53+/- mice of the 25, 50, and 75 mg/kg groups, respectively. The main tumor types in FVB-Trp53+/- mice were TML and primary lung tumors, regardless of the dose of MNU administered. These results suggest that systemic tumors may result from malfunctions in the p53 gene and pathway, which is an important factor in the pathogenesis of human cancers. Therefore, FVB-Trp53 heterozygous mice are suitable for short-term carcinogenicity tests using positive carcinogens, and that the best result using MNU, a positive carcinogen, might have a single dose of 50 mg/kg.
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Neoplasias Pulmonares , Neoplasias del Timo , Humanos , Ratones , Masculino , Animales , Metilnitrosourea/toxicidad , Carcinógenos/toxicidad , Ratones Endogámicos , Pruebas de Carcinogenicidad/métodosRESUMEN
The growing incidence of prostate cancer has prompted a great investment in basic biology and translational studies to develop new therapies. Multiple animal models have been established to study etiological factors, cancer-preventive strategies and the molecular determinants of aggressiveness and metastases. The rat model of prostate cancer induced by chemical carcinogen N-methyl-N-nitrosourea (MNU) and testosterone exposure has become an important tool to study prostatic carcinogenesis and chemopreventive approaches. Over prolonged treatment, this model develops prostatic lesions that closely mimic those observed in human patients. By modifying the experimental conditions, different research groups have been able to induce a vast spectrum of lesions, ranging from early prostatic intraepithelial neoplasia to metastatic cancer. These carefully tuned experimental settings allowed researchers to test lifestyle interventions, and different pharmacological and chemopreventive strategies. However, this model's great flexibility requires careful planning to ensure that the experimental conditions are adequate to obtain the spectrum of lesions intended. The present review addresses such issues, highlighting the value of the rat prostate cancer model and the multiple challenges and opportunities it offers to researchers worldwide.
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Neoplasias de la Próstata , Investigación Biomédica Traslacional , Humanos , Masculino , Ratas , Animales , Metilnitrosourea/toxicidad , Neoplasias de la Próstata/patología , Testosterona/efectos adversos , Modelos Animales de EnfermedadRESUMEN
Perinatal and neonatal exposure to bisphenol A (BPA) has been linked to enhancement of prostate carcinogenesis in rats induced by combined treatment with estradiol and testosterone, but human data are lacking. This study aimed to determine the effects of perinatal BPA exposure on induction of prostate cancer in rats by sequential treatment with N-methyl-N-nitrosamine (MNU) and continuous low dose administration of testosterone. Pregnant Sprague Dawley rats were exposed to BPA administered by subcutaneous Alzet minipumps at doses of 2.5 or 25 µg/kg body weight/day from gestational day 9 until postnatal day 28 when pups were weaned providing exposure of offspring in utero and via the mother's milk. At 10-12 weeks of age, one male offspring per litter was treated with an intraperitoneal injection of MNU after hormonal stimulation of prostatic cell proliferation followed two weeks later by subcutaneous insertion of Silastic implants containing testosterone until the termination of the study 57-58 weeks after MNU injection. The perinatal BPA exposure did not significantly affect the incidence of prostate carcinomas which was slightly lower in exposed rats (33-23 %) than in control animals (40 %). Carcinomas in all accessory sex glands combined were also insignificantly less frequent in exposed (46-48 %) than in control rats (60 %). The incidence of malignant tumors at any site in the body was significantly lower in exposed rats (81-65 %) than in controls (93 %). In conclusion, perinatal BPA exposure did not significantly modify prostate cancer induction by MNU plus testosterone in rats, unlike the enhancement of prostate carcinogenesis induced by treatments involving estradiol administration. Which of the two models of prostate carcinogenesis is more relevant for the human situation is unclear at present.
Asunto(s)
Carcinoma , Neoplasias de la Próstata , Embarazo , Humanos , Ratas , Masculino , Animales , Recién Nacido , Testosterona , Ratas Sprague-Dawley , Metilnitrosourea/toxicidad , Neoplasias de la Próstata/inducido químicamente , Neoplasias de la Próstata/patología , Compuestos de Bencidrilo/toxicidad , Estradiol/toxicidad , CarcinogénesisRESUMEN
PURPOSE: In this study, two main research objectives were examined: (1) the cytotoxic and anticancer activities of the aqueous methanol extract from Acacia nilotica flowers on three human cancer cells, namely lung A549, breast MCF-7, and leukemia THP-1 cells, and (2) the genotoxic effects of A. nilotica extract and its influence on DNA damage induced by N-methyl-N-nitrosourea (MNU) in mice. METHODS: Mice were orally treated with A. nilotica extract (200, 500, and 800 mg/kg for 4 days) with or without MNU (80 mg/kg intraperitoneally for 24 h). RESULTS: In vitro experiments showed that A549 cells were the most sensitive to A. nilotica extract among the tested cell lines. A. nilotica extract inhibited A549 cell proliferation by blocking the cell cycle at the G2/M phase and accumulating apoptotic cells in the sub-G0/G1 phase in A549 cells. In vivo experiments showed that MNU induced positive and negative genotoxicity in bone marrow cells and spermatocytes, respectively. Negative genotoxicity was observed in A. nilotica extract-treated groups only. However, A. nilotica extract (800 mg/kg) remarkably increased comet tail formation in bone marrow cells. Unexpectedly, the absence of antigenotoxicity was observed in three cotreated groups with A. nilotica extract and MNU compared with the MNU-treated group. Astonishingly, cotreatment with MNU and A. nilotica extract at a dose above 200 mg/kg remarkably increased micronucleus and comet tail formation in bone marrow cells compared with the MNU-treated group. CONCLUSIONS: A. nilotica extract possessed anticancer activity with relative genotoxic effects at high doses.
Asunto(s)
Acacia , Antineoplásicos , Animales , Daño del ADN , Flores , Humanos , Masculino , Metilnitrosourea/toxicidad , Ratones , Extractos Vegetales/farmacologíaRESUMEN
PURPOSE: Among diverse Pattern Recognition Receptors (PRRs), Toll-like receptor-4 (TLR-4) is a key urothelial trigger for innate immune response impacting urothelial bladder carcinoma (BC). Androgen activation promotes immunotolerance, playing an immunoregulatory role by unknown mechanisms. We explored the castration impact on urothelial TLR-4 modulation in carcinogenesis and immunotherapeutic scenario. METHODS: Intact (SHAM) versus castrated male Fisher-344 rats were evaluated in 2 scenarios: (A) Carcinogenesis: After randomization to SHAM (n = 5) and Castration (n = 5), carcinogenesis was induced by four intravesical doses of 1.5 mg/kg n-methyl-n-nitrosourea (MNU) every 15 days. (B) Treatment: After ultrasonographic confirmed MNU-induced papillary BC on week 8, rats were randomized to SHAM (n = 5) and Castration (n = 5) and offered 6 weekly intravesical treatment of 106 CFU of bacillus Calmette Guerin (BCG) in 0.2 ml saline. After 15 weeks the urinary bladders underwent histopathology. Urothelial cell proliferation was measured by Ki-67 immunohistochemistry (IHC), and TLR-4 expression was quantified by IHC and WB. RESULTS: Castration induced higher TLR-4 urothelial expression (p = 0.007) and anticarcinogenic effect with fewer urothelial tumors (60 vs. 80%) and lower urothelial cell proliferation compared to intact animals (p = 0.008). In the intravesical BCG treatment setting, castration has potentialized the BCG activation of TLR-4 (p = 0.007) with no residual in situ carcinoma compared to intact animals, suggesting the potential to amplify the BCG immune response. CONCLUSION: To our knowledge, this is the first description of TLR-4 urothelial expression hormonal modulation. The described castration-mediated immunomodulation will help to improve the knowledge of urothelial cancer gender diversities and PRRs modulations with treatment implications.
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Castración , Neoplasias de la Vejiga Urinaria , Adyuvantes Inmunológicos , Administración Intravesical , Andrógenos , Animales , Anticarcinógenos , Vacuna BCG/uso terapéutico , Carcinogénesis/inducido químicamente , Carcinoma de Células Transicionales/patología , Antígeno Ki-67 , Masculino , Metilnitrosourea/toxicidad , Ratas , Receptor Toll-Like 4 , Neoplasias de la Vejiga Urinaria/patologíaRESUMEN
N-methyl-N-nitrosourea (MNU) is a prevalent environmental carcinogen, which leads to tumors in various organs in animal models, while the mechanisms involved were still not fully understood. It is well known that anomalous angiogenesis is a key step in tumorigenesis and progression. In this study, we found that MNU induced abnormal angiogenesis which was accompanied by upregulation of rspo1, p53 and vegfaa in zebrafish embryos. Moreover, it revealed that MNU-induced ectopic sprouting of blood vessels was significantly reduced in rspo1-knockdown but not p53-knockdown embryos, indicating that rspo1 was necessary for MNU-induced abnormal angiogenesis. Additionally, pharmaceutical activation or inhibition of Wnt/ß-catenin signaling pathway using (2'Z,3'E)- 6-bromoindirubin-3'-oxime or CCT036477 significantly increased or inhibited the pro-angiogenic effect of MNU on developing zebrafish embryos, which was confirmed by the effect of proliferation and migration in MNU-treated bEnd.3 cells. These data together indicated that rspo1/Wnt/ß-catenin/vegfaa axis is involved in the modulation of MNU-induced anomalous angiogenesis.
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Metilnitrosourea , Neovascularización Patológica , Vía de Señalización Wnt , Pez Cebra , Animales , Células Endoteliales/metabolismo , Metilnitrosourea/toxicidad , Ratones , Neovascularización Patológica/inducido químicamente , Pez Cebra/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
BACKGROUND/AIM: Genetic and environmental factors interact to dictate the risk of cancer, and animal models are expected to provide avenues for identifying such interactions. The aim of the study was to clarify the genetic susceptibility of Copenhagen rats to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis. MATERIALS AND METHODS: Female Copenhagen and Sprague- Dawley rats and their F1 hybrids were subjected at age 7 weeks to γ-irradiation or intraperitoneal injection with 1-methyl-1-nitrosourea or were not treated, and palpable mammary tumours were diagnosed histologically. Data were pooled with previous data acquired for both nontreated and irradiated Sprague-Dawley rats. RESULTS: Radiation and 1-methyl-1-nitrosourea both significantly increased the incidence of mammary cancer in all strains. Copenhagen and F1 rats displayed a significantly lower incidence than Sprague-Dawley rats in all groups, with relatively higher incidence after irradiation. F1 rats exhibited significantly higher mammary cancer incidence than Copenhagen rats in the nontreated, but not the treated, groups. The interaction of the strain and exposure effects was suggested to be quasi-multiplicative. CONCLUSION: Copenhagen rats display non-uniform resistance to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis with dominant inheritance over Sprague-Dawley rats.
Asunto(s)
Neoplasias de la Mama , Neoplasias Mamarias Experimentales , Animales , Transformación Celular Neoplásica , Femenino , Humanos , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/genética , Metilnitrosourea/toxicidad , Ratas , Ratas Sprague-DawleyRESUMEN
Calliandra portoricensis (C. portoricensis) is used in herbal homes in Nigeria to manage breast diseases. We investigated the anti-tumourigenic effects of chloroform extract of C. portoricensis (CP) in breast experimental cancer induced by N-methyl-N-nitrosourea (NMU) and benzo-(a)-pyrene (BaP). Fifty-six female rats were assigned into seven equal groups: Group 1 served as control, group 2 received NMU and BaP (50 mg/kg, each), groups 3 and 4 received [NMU + BaP] and treated with CP at 50 and 100 mg/kg, respectively. Group 5 received CP (100 mg/kg), group 6 received [NMU + BaP] and vincristine (0.5 mg/kg), while group 7 received vincristine (0.5 mg/kg). The NMU and BaP (i.p) were dissolved in normal saline and corn oil, respectively. The CP (oral) and vincristine (i.p) were given thrice and twice per week, respectively for 10 weeks. The [NMU + BaP] intoxication significantly decreased body weight gain by 32% while organo-somatic weight of mammary gland increased by 37%. Also, [NMU + BaP] decreased the activities of mammary catalase, glutathione-s-transferase, glutathione peroxidase, superoxide dismutase and total sulphurhydryl by 34%, 31%, 35%, 35% and 33%, respectively. The [NMU + BaP] increased inflammatory and oxidative stress markers; nitrite, lipid peroxidation and myeloperoxidase by 62%, 57% and 361%, respectively. Strong expression of BCL-2, IL-6, COX 2, ß-catenin and iNOS in [NMU + BaP]-administered rats were observed. Histology revealed glands with malignant epithelial cells and high nucleocytoplasm in [NMU + BaP] rats. Treatment with CP attenuated inflammation, apoptosis and restored cyto-architecture of mammary gland. Overall, CP abates mammary tumourigenesis by targeting cellular pathways of inflammation and apoptosis.
Asunto(s)
Metilnitrosourea , Neoplasias , Extractos Vegetales , Animales , Femenino , Ratas , Benzo(a)pireno/toxicidad , beta Catenina , Carcinogénesis , Catalasa/metabolismo , Cloroformo , Ciclooxigenasa 2 , Glutatión/metabolismo , Glutatión Transferasa/metabolismo , Inflamación , Interleucina-6 , Metilnitrosourea/toxicidad , Nitritos , Peroxidasa , Extractos Vegetales/farmacología , Proteínas Proto-Oncogénicas c-bcl-2 , Superóxido Dismutasa/metabolismo , Vincristina , Fabaceae/químicaRESUMEN
Retinal prosthesis is regarded as the treatment for vision restoration in the blind with retinal degeneration (RD) due to the loss of photoreceptors. A strategy for retinal prosthesis is to electrically activate surviving neurons. The retina's response to electrical stimulation in a larger RD model has not been studied yet. Therefore, in this study, we investigated electrically evoked retinal responses in a previously validated N-methyl-N-nitrosourea (MNU)-induced porcine RD model. Electrically evoked responses were evaluated based on the number of retinal ganglion cell (RGC) spikes via multichannel recordings. Stimulation pulses were applied to degenerative and wild-type retinas with pulse modulation. Compared to wild-type retinas, degenerative retinas showed higher threshold values of pulse amplitude and pulse duration. The rate of increase in the number of RGC spikes relative to stimulus intensity was lower in degenerative retinas than in normal retinas. In severely degenerated retinas, few RGCs showed electrically evoked spikes. Our results suggest that the degenerative porcine retina requires a higher charge than the normal porcine retina. In the early stage of RD, it is easier to induce RGC spikes through electrical stimulation using retinal prosthesis; however, when the degeneration is severe, there may be difficulty recovering patient vision.
Asunto(s)
Potenciales Evocados Visuales/efectos de los fármacos , Metilnitrosourea/toxicidad , Degeneración Retiniana , Células Ganglionares de la Retina/metabolismo , Animales , Modelos Animales de Enfermedad , Estimulación Eléctrica , Femenino , Degeneración Retiniana/inducido químicamente , Degeneración Retiniana/metabolismo , Degeneración Retiniana/fisiopatología , Porcinos , Porcinos EnanosRESUMEN
The need of pharmacological strategies to preclude breast cancer development motivated us to develop a non-aqueous microemulsion (ME) capable of forming a depot after administration in the mammary tissue and uptake of interstitial fluids for prolonged release of the retinoid fenretinide. The selected ME was composed of phosphatidylcholine/tricaprylin/propylene glycol (45:5:50, w/w/w) and presented a droplet diameter of 175.3 ± 8.9 nm. Upon water uptake, the ME transformed successively into a lamellar phase, gel, and a lamellar phase-containing emulsion in vitro as the water content increased and released 30% of fenretinide in vitro after 9 days. Consistent with the slow release, the ME formed a depot in cell cultures and increased fenretinide IC50 values by 68.3- and 13.2-fold in MCF-7 and T-47D cells compared to a solution, respectively. At non-cytotoxic concentrations, the ME reduced T-47D cell migration by 75.9% and spheroid growth, resulting in â¼30% smaller structures. The depot formed in vivo prolonged a fluorochrome release for 30 days without producing any sings of local irritation. In a preclinical model of chemically induced carcinogenesis, ME administration every 3 weeks for 3 months significantly reduced (4.7-fold) the incidence of breast tumors and increased type II collagen expression, which might contribute to limit spreading. These promising results support the potential ME applicability as a preventive therapy of breast cancer.
Asunto(s)
Anticarcinógenos/administración & dosificación , Neoplasias de la Mama/prevención & control , Fenretinida/administración & dosificación , Neoplasias Mamarias Experimentales/prevención & control , Animales , Anticarcinógenos/farmacocinética , Neoplasias de la Mama/inducido químicamente , Neoplasias de la Mama/patología , Supervivencia Celular/efectos de los fármacos , Preparaciones de Acción Retardada/administración & dosificación , Preparaciones de Acción Retardada/farmacocinética , Liberación de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Emulsiones , Femenino , Fenretinida/farmacocinética , Humanos , Concentración 50 Inhibidora , Células MCF-7 , Glándulas Mamarias Animales/efectos de los fármacos , Glándulas Mamarias Animales/patología , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/patología , Metilnitrosourea/administración & dosificación , Metilnitrosourea/toxicidad , Ratones , RatasRESUMEN
Phthalates metabolites have been detected in the urine of pregnant and breastfeeding women. Thus, this study evaluated the adverse effects of maternal exposure to a mixture of six phthalates (Pth mix) on the mammary gland development and carcinogenesis in F1 female offspring. Pregnant female Sprague-Dawley rats were exposed daily to vehicle or Pth mix (35.22% diethyl-phthalate, 21.03% di-(2-ethylhexyl)-phthalate, 14.91% dibutyl-phthalate, 15.10% diisononyl-phthalate, 8.61% diisobutyl-phthalate, and 5.13% benzylbutyl-phthalate) by gavage at 20 µg/kg, 200 µg/kg or 200 mg/kg during gestational day 10 (GD 10) to postnatal day 21 (PND 21). After weaning (PND 22), some female offspring were euthanized for mammary gland analyses while other females received a single dose of N-methyl-N-nitrosourea (MNU, 50 mg/kg) or vehicle and then tumor incidence and multiplicity were recorded until PND 180. Maternal Pth mix exposure increased the number of Ki-67 and progesterone receptor-positive epithelial cells in the mammary gland from Pth mix 200 at µg/kg and 200 mg/kg groups. In addition, tumor incidence and mean number were higher only in Pth mix at 200 mg/kg when compared to the vehicle-treated group, and percentage of tumor-free animals was lower in Pth mix at 200 µg/kg and 200 mg/kg groups. The findings indicate that perinatal Pth mixture exposure increased susceptibility to MNU-induced mammary carcinogenesis in adult F1 female offspring.