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1.
Food Funct ; 12(21): 10632-10643, 2021 Nov 01.
Article in English | MEDLINE | ID: mdl-34585698

ABSTRACT

Safflower yellow (SY) is the main active ingredient isolated from the traditional Chinese medicine Carthamus tinctorius, which is a valuable natural edible pigment that is widely used to treat cerebrovascular and cardiovascular diseases. However, the effect of SY on hepatocellular carcinoma (HCC) remains unclear. In this study, we showed that SY decreased the degree of injury and inhibited the release of inflammatory factors in the liver of a diethylnitrosamine (DEN)-induced HCC mouse model. Flow cytometry and immunoblotting showed that SY increased the infiltration of CD8+ T cells and Gr-1+ macrophages to improve the immune microenvironment by affecting the expression of collagen fibers. Further cellular experiments showed that SY degraded the collagens in the liver cells through the TGF-ß/Smad signalling pathway. SY also regulated the gut microbiota which may contribute to the immune microenvironment. In conclusion, SY exhibited a potent effect on the development of HCC by enhancing liver immune infiltration by promoting collagen degradation and modulating the gut microbiota. This study provides novel insights into the mechanism of SY as a candidate for the treatment of HCC in the future.


Subject(s)
Carcinoma, Hepatocellular/chemically induced , Chalcone/analogs & derivatives , Diethylnitrosamine/toxicity , Gastrointestinal Microbiome/drug effects , Liver Neoplasms/chemically induced , Liver/drug effects , Animals , Carcinoma, Hepatocellular/prevention & control , Cell Line, Tumor , Chalcone/pharmacology , Collagen/metabolism , Humans , Liver/immunology , Liver/metabolism , Liver Neoplasms/prevention & control , Macrophages, Peritoneal/drug effects , Male , Mice , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/prevention & control , Tumor Microenvironment/drug effects , Tumor Microenvironment/immunology
2.
J Ethnopharmacol ; 280: 114415, 2021 Nov 15.
Article in English | MEDLINE | ID: mdl-34271113

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Angelica sinensis is widely used in traditional Chinese Medicine for relieving gynecological discomforts among the women population. However, its hormone-like effects have raised great attention on whether it is appropriate to use in breast cancer (BC) patients. Hence, this study aimed to investigate the tumorigenic effect of aqueous root extract of Angelica sinensis (AS) on estrogen receptor (ER)-positive BC growth through ER-induced stemness in-vitro and in-vivo. MATERIALS AND METHODS: The chemical composition of the AS was characterized by HPLC. Cell viability was detected by MTS assay. The in-vivo effect of AS was investigated by xenograft model, immunohistochemistry, histology, Western blot, and self-renewal ability assay. Target verification was used by shRNA construction and transfection. Mammosphere formation assay was performed by flow cytometry. RESULTS: AS significantly promoted the proliferation of MCF-7 cells and inhibited the growth of MDA-MB-231 cells. AS significantly induced tumor growth (2.5 mg/kg) in xenograft models and however tamoxifen treatment significantly suppressed the AS-induced tumor growth. AS induced ERα expression in both in-vivo and in-vitro and promoted cancer stem cell activity in ER-positive BC. CONCLUSION: AS shows the tumorigenic potential on ER-positive BC growth through ERα induced stemness, suggesting that the usage of AS is not recommended for BC in terms of safety measures.


Subject(s)
Angelica sinensis/chemistry , Breast Neoplasms/chemically induced , Breast Neoplasms/drug therapy , Carcinogenesis/chemically induced , Plant Extracts/adverse effects , Receptors, Estrogen/metabolism , Animals , Antineoplastic Agents/therapeutic use , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Female , Humans , MCF-7 Cells , Mice , Mice, Nude , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/drug therapy , Neoplastic Stem Cells , Plant Extracts/therapeutic use , Plant Roots/chemistry , Receptors, Estrogen/genetics , Tamoxifen/therapeutic use
3.
J Biochem Mol Toxicol ; 35(5): e22723, 2021 May.
Article in English | MEDLINE | ID: mdl-33511709

ABSTRACT

Gastric carcinoma is one of the most aggressive types of cancer that ranks fifth among all cancer incidences and third in cancer mortality. As it exhibits a prolonged asymptomatic condition and high recurrence rate, it is a great challenge to treat gastric cancer. Traditional medicine that utilizes herbal phytochemicals to treat various diseases is a potent alternative for current allopathic treatment. Hence, we evaluated the potency of a phytochemical bilobalide for treating gastric cancer in in vitro and in vivo models. Bilobalide, a sesquiterpenoid, is present in the Ginkgo biloba plant that belongs to the family of Ginkgoaceae. The cytotoxicity effect of bilobalide was evaluated in both gastric cancer (AGS) cells and normal gastric epithelial cells. Apoptosis-inducing property of bilobalide against the AGS cell line was analyzed with different fluorescent staining techniques and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and cell cycle analysis was carried out by flow cytometry. The in vivo studies were assessed with N-methyl-N-nitrosourea (MNU)-induced gastric cancer in rats. Serum-specific gastric markers were quantified and histopathological analysis of stomach tissue was performed. The expression of target-signaling molecules was analyzed by a reverse-transcription polymerase chain reaction. The in vitro results proved that bilobalide effectively suppressed the AGS cell growth and induced cell death by nuclear damage and apoptosis induction. The bilobalide treatment effectively arrested the cell cycle of AGS cells via inhibiting the PI3K-signaling pathway. Our in vivo results also confirmed that the bilobalide persuasively inhibited the MNU-induced gastric carcinoma via inhibiting the thioredoxin-fold family proteins and inflammatory markers' expression. Overall, our results authentically prove that bilobalide possesses therapeutic potency to cure gastric carcinoma.


Subject(s)
Apoptosis/drug effects , Bilobalides/pharmacology , Cell Proliferation/drug effects , Neoplasms, Experimental/drug therapy , Plant Extracts/chemistry , Stomach Neoplasms/drug therapy , Animals , Bilobalides/chemistry , Cell Line, Tumor , Ginkgo biloba , Humans , Male , Methylnitrosourea/toxicity , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Rats , Rats, Wistar , Stomach Neoplasms/chemically induced , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology
4.
Int J Cancer ; 148(1): 226-237, 2021 01 01.
Article in English | MEDLINE | ID: mdl-32700769

ABSTRACT

Hepatocellular carcinoma (HCC) is highly resistant to anticancer therapy and novel therapeutic strategies are needed. Chronotherapy may become a promising approach because it may improve the efficacy of antimitotic radiation and chemotherapy by considering timing of treatment. To date little is known about time-of-day dependent changes of proliferation and DNA damage in HCC. Using transgenic c-myc/transforming growth factor (TGFα) mice as HCC animal model, we immunohistochemically demonstrated Ki67 as marker for proliferation and γ-H2AX as marker for DNA damage in HCC and surrounding healthy liver (HL). Core clock genes (Per1, Per2, Cry1, Cry2, Bmal 1, Rev-erbα and Clock) were examined by qPCR. Data were obtained from samples collected ex vivo at four different time points and from organotypic slice cultures (OSC). Significant differences were found between HCC and HL. In HCC, the number of Ki67 immunoreactive cells showed two peaks (ex vivo: ZT06 middle of day and ZT18 middle of night; OSC: CT04 and CT16). In ex vivo samples, the number of γ-H2AX positive cells in HCC peaked at ZT18 (middle of the night), while in OSC their number remained high during subjective day and night. In both HCC and HL, clock gene expression showed a time-of-day dependent expression ex vivo but no changes in OSC. The expression of Per2 and Cry1 was significantly lower in HCC than in HL. Our data support the concept of chronotherapy of HCC. OSC may become useful to test novel cancer therapies.


Subject(s)
Carcinoma, Hepatocellular/genetics , Liver Neoplasms/genetics , Neoplasms, Experimental/genetics , Period Circadian Proteins/genetics , Animals , Carcinoma, Hepatocellular/chemically induced , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/therapy , Cell Proliferation/genetics , Chlorides/administration & dosage , Chlorides/toxicity , Chronotherapy , DNA Damage , Gene Expression Regulation, Neoplastic , Humans , Liver/pathology , Liver Neoplasms/chemically induced , Liver Neoplasms/pathology , Liver Neoplasms/therapy , Mice , Mice, Transgenic , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/therapy , Photoperiod , Proto-Oncogene Proteins c-myc/genetics , Transforming Growth Factor alpha/genetics , Tumor Cells, Cultured , Zinc Compounds/administration & dosage , Zinc Compounds/toxicity
5.
Biosci Rep ; 40(11)2020 11 27.
Article in English | MEDLINE | ID: mdl-33165619

ABSTRACT

BACKGROUND: Over the past few years, fabrication of nanoparticles (NPs) has been deployed widely in technologies and many concerns have emerged about the hazardous effect on human health after NPs exposure. OBJECTIVE: Green synthesis of gold NPs (AuNPs) and assessment of their activity in 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer mouse model. METHODS: Chloroauric acid (HAuCl4) was used in formation of AuNPs with the help of Curcuma longa as aqueous reducing extract and stabilizing agent at room temperature. Formed NPs were characterized with UV-Vis spectrometry, Fourier-transform infrared spectroscopy (FTIR), Zetasizer measurement, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Virgin female albino mice with DMBA-induced breast cancer were treated with formed AuNPs for 5 consecutive days and were dissected after 28 days of the beginning of treatment. RESULTS: UV-Vis spectrometry showed absorbance maximum peak at 530 nm for formed AuNPs, FTIR confirmed formation of plant extract layer around formed NPs; zetasizer measurement revealed 278.2 nm as an average size of produced NPs; SEM and TEM approved formation of monodisperse spherical AuNPs. Biochemical analysis of untreated breast cancer group revealed marked changes in liver and kidney functions manifested by raised activity levels of alanine transaminase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine. Whereas, the treated group with AuNPs post-breast cancer induction displayed reduction in the activities (of ALT, AST and creatinine), while the BUN activity level was raised. Histopathological examination showed heavy incidence of tumor foci in the breast and lymph nodes belonged to the untreated breast cancer group confirmed with intense response to Ki-67 antibodies. While the treated group with AuNPs post-breast cancer induction showed degenerated tumor foci in the breast and lymph nodes with weak response to Ki-67 antibodies. CONCLUSION: AuNPs were successfully synthesized using HAuCl4 and C. longa extract confirmed their ability to control DMBA-induced breast cancer in virgin female Swiss albino mice.


Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/drug therapy , Chlorides/pharmacology , Gold Compounds/pharmacology , Green Chemistry Technology , Metal Nanoparticles , Nanomedicine , Neoplasms, Experimental/drug therapy , 9,10-Dimethyl-1,2-benzanthracene , Alanine Transaminase/blood , Animals , Antineoplastic Agents/chemistry , Aspartate Aminotransferases/blood , Blood Urea Nitrogen , Breast Neoplasms/blood , Breast Neoplasms/chemically induced , Breast Neoplasms/pathology , Cell Proliferation/drug effects , Chlorides/chemistry , Creatinine/blood , Curcuma/chemistry , Excipients/chemistry , Female , Gold Compounds/chemistry , Mice , Neoplasms, Experimental/blood , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Oxidation-Reduction , Plant Extracts/chemistry , Tumor Burden/drug effects
6.
World J Gastroenterol ; 26(17): 2064-2081, 2020 May 07.
Article in English | MEDLINE | ID: mdl-32536775

ABSTRACT

BACKGROUND: Epigallocatechin gallate (EGCG) is a polyhydroxy phenolic compound extracted from tea and its antitumor effect has received widespread attention. We explored the inhibitory effect of EGCG on dimethylhydrazine (DMH)-induced colorectal cancer (CRC) using a rat model, predicted the interaction between EGCG and CRC target genes using a database, and explained the EGCG associated target pathways and mechanisms in CRC. AIM: To understand the inhibitory mechanisms of EGCG on CRC cell proliferation and identify its pharmacological targets by network pharmacology analysis. METHODS: DMH (40 mg/kg, s.c., twice weekly for eight weeks) was used to induce CRC in rats. After model establishment, the rats were administered with EGCG (50, 100, or 200 mg/kg, p.o., once daily for eight weeks) and killed 12 and 20 wk after the start of the experiment. Formation of aberrant crypt foci and tumor was studied by histological analysis. Using network pharmacology analysis, candidate and collective targets of EGCG and CRC were identified, and Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses were used to predict the pathways altered by EGCG. RESULTS: At week 12, high-dose EGCG treatment significantly reduced the tumor formation rate, total number of tumors, cancerous and non-cancerous tumors, tumor volume, ascites formation, and aberrant crypt foci count. At week 20, all three doses of EGCG were effective. Seventy-eight collective targets of EGCG and CRC were identified, of which 28 genes were dysregulated in CRC. Kyoto Encyclopedia of Genes and Genomes and GO analyses showed that the dysregulated genes were enriched in hsa05210 (CRC), hsa04115 (p53 signaling pathway), and hsa04151 (PI3K-Akt signaling pathway), GO:0043124 (negative regulation of I-kappaB kinase/NF-kappaB signaling pathway), GO:0043409 (negative regulation of mitogen-activated protein kinase cascade), and GO:2001244 (positive regulation of intrinsic apoptotic signaling pathway) respectively. CONCLUSION: EGCG inhibits the formation of DMH-induced CRC by regulating key pathways involved in tumorigenesis.


Subject(s)
Aberrant Crypt Foci/prevention & control , Anticarcinogenic Agents/pharmacology , Catechin/analogs & derivatives , Colorectal Neoplasms/prevention & control , Neoplasms, Experimental/prevention & control , Aberrant Crypt Foci/chemically induced , Aberrant Crypt Foci/genetics , Aberrant Crypt Foci/pathology , Animals , Anticarcinogenic Agents/therapeutic use , Carcinogenesis/drug effects , Carcinogenesis/genetics , Catechin/pharmacology , Catechin/therapeutic use , Cell Proliferation/drug effects , Cell Proliferation/genetics , Colon/drug effects , Colon/pathology , Colorectal Neoplasms/chemically induced , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Dimethylhydrazines/toxicity , Gene Expression Regulation, Neoplastic/drug effects , Gene Regulatory Networks/drug effects , Humans , Intestinal Mucosa/drug effects , Intestinal Mucosa/pathology , Male , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/genetics , Neoplasms, Experimental/pathology , Protein Interaction Maps/drug effects , Protein Interaction Maps/genetics , Rats , Rectum/drug effects , Rectum/pathology , Signal Transduction/drug effects , Signal Transduction/genetics
7.
Cancer Med ; 9(11): 3964-3973, 2020 06.
Article in English | MEDLINE | ID: mdl-32243710

ABSTRACT

Naturally occurring tumor in animals receiving high minerals from deep oceans (DOM: hardness 600 mg/L) from 6 months of age until natural death was firstly assessed in 200 Sprague Dawley rats, randomized into four groups: Control (C), DOM (D), Fructose (F), and Fructose + DOM (FD). Fructose drink contained 11% fructose. Tumor incidence (necropsy at death) in the D group was ~40% lower than that in the C group (P < .05), together with lower body mass gain and greater locomotive activity during their initial 18 months (P < .05) but not during later life. X-ray image analysis on abnormal solid tissue among survivors at 18 and 24 months of age confirms a similar trend, exhibiting ~50% and ~65% lower tumor incidence than the C and F groups, respectively. Reduced-to-oxidized glutathione ratio (GSH/GSSG) declined with age for the first three quarters of life on all groups (P < .05), followed by a resurgence during end-life among survivors at 24 months. This resurgence is markedly associated with lower tumor expansion but unrelated with DOM supplementation. Our results demonstrate valuable application of minerals and trace elements from deep oceans, as a vastly available natural source, on tumor suppression during normal aging.


Subject(s)
Carcinogenesis/drug effects , Fructose/toxicity , Minerals/pharmacology , Neoplasms, Experimental/prevention & control , Sweetening Agents/toxicity , Animals , Carcinogenesis/pathology , Female , Life Expectancy , Male , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Oceans and Seas , Rats , Rats, Sprague-Dawley
8.
Proc Natl Acad Sci U S A ; 117(11): 6075-6085, 2020 03 17.
Article in English | MEDLINE | ID: mdl-32123074

ABSTRACT

MicroRNA-31 (miR-31) is overexpressed in esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary Zn deficiency and inflammation. In a Zn deficiency-promoted rat ESCC model with miR-31 up-regulation, cancer-associated inflammation, and a high ESCC burden following N-nitrosomethylbenzylamine (NMBA) exposure, systemic antimiR-31 delivery reduced ESCC incidence from 85 to 45% (P = 0.038) and miR-31 gene knockout abrogated development of ESCC (P = 1 × 10-6). Transcriptomics, genome sequencing, and metabolomics analyses in these Zn-deficient rats revealed the molecular basis of ESCC abrogation by miR-31 knockout. Our identification of EGLN3, a known negative regulator of nuclear factor κB (NF-κB), as a direct target of miR-31 establishes a functional link between oncomiR-31, tumor suppressor target EGLN3, and up-regulated NF-κB-controlled inflammation signaling. Interaction among oncogenic miR-31, EGLN3 down-regulation, and inflammation was also documented in human ESCCs. miR-31 deletion resulted in suppression of miR-31-associated EGLN3/NF-κB-controlled inflammatory pathways. ESCC-free, Zn-deficient miR-31-/- rat esophagus displayed no genome instability and limited metabolic activity changes vs. the pronounced mutational burden and ESCC-associated metabolic changes of Zn-deficient wild-type rats. These results provide conclusive evidence that miR-31 expression is necessary for ESCC development.


Subject(s)
Esophageal Neoplasms/genetics , Esophageal Squamous Cell Carcinoma/genetics , Hypoxia-Inducible Factor-Proline Dioxygenases/genetics , MicroRNAs/metabolism , Neoplasms, Experimental/genetics , Animals , Carcinogens/toxicity , Cell Line, Tumor , Dietary Supplements , Esophageal Neoplasms/chemically induced , Esophageal Neoplasms/pathology , Esophageal Neoplasms/prevention & control , Esophageal Squamous Cell Carcinoma/chemically induced , Esophageal Squamous Cell Carcinoma/pathology , Esophageal Squamous Cell Carcinoma/prevention & control , Esophagus/pathology , Gene Expression Regulation, Neoplastic , Gene Knockout Techniques , Humans , Male , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , NF-kappa B/metabolism , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Neoplasms, Experimental/prevention & control , Nitrosamines/toxicity , Rats , Rats, Transgenic , Signal Transduction/genetics , Zinc/administration & dosage , Zinc/deficiency
9.
Phytomedicine ; 67: 153152, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31887479

ABSTRACT

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths worldwide. Several targets have been identified for lung cancer therapy, amongst which 'Microtubule' and its dynamics are the most widely studied and used in therapy. Tubulin-microtubule polymer dynamics are highly sought after targets in the field of anti-cancer drug designing. Natural compounds are important sources for developing anticancer therapeutics owing to their efficacy and lower cytotoxicity. Evidence suggested that therapeutic targeting of microtubule by natural compounds is amongst the most widely used interventions in numerous cancer therapies including lung cancer. PURPOSE: To determine the efficacy of apocynin (a natural compound) in suppressing the progression of lung carcinoma both in vitro and in vivo, along with the identification of targets and the underlying mechanism for developing a novel therapeutic approach. METHODS: We have demonstrated themicrotubule depolymerizing role of apocynin by established protocols in cellular and cell-free system. The efficacy of apocynin to inhibit lung carcinoma progression was studied on A549 cells.The tumoricidal ability of apocynin was studied in BALB/c mice model as well.Mice were classified into 4 groups namely-group II mice as tumor control; group III-IV mice asalso tumor-induced but treated with differential apocynin doses whereas group I mice were kept as normal. RESULTS: Apocynin, showed selective cytotoxicity towards lung cancer cells rather than normal lung fibroblast cells. Apocynin inhibited oncogenic properties including growth, proliferation (p < 0.05), colony formation (p < 0.05), invasion (p < 0.05) and spheroid formation (p < 0.05) in lung cancer cells. Apart from other established properties, apocynin was found to be a novel and potent component to bind with tubulin and depolymerize cellular microtubule network. Apocynin mediated cellular microtubule depolymerization was the driving mechanism to trigger autophagy-mediated apoptotic cell death (p < 0.05) which in turn retarded lung cancer progression. Furthermore, apocynin showed tumoricidal characteristics to inhibit lung tumorigenesis in mice as well. CONCLUSION: Targeting tubulin-microtubule equilibrium with apocynin could be the key regulator to catastrophe cellular catabolic processes to mitigate lung carcinoma. Thus, apocynin could be a potential therapeutic agent for lung cancer treatment.


Subject(s)
Acetophenones/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Autophagy/drug effects , Lung Neoplasms/drug therapy , Tubulin Modulators/pharmacology , A549 Cells , Acetophenones/chemistry , Animals , Antineoplastic Agents, Phytogenic/chemistry , Cell Line, Tumor , Humans , Lung Neoplasms/pathology , Male , Mice, Inbred BALB C , Microtubules/metabolism , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/pathology , Tubulin/chemistry , Tubulin/metabolism , Tubulin Modulators/chemistry
10.
Nutr Cancer ; 72(1): 157-169, 2020.
Article in English | MEDLINE | ID: mdl-31155951

ABSTRACT

Ginger (Zingiber officinale) is a spice and also an herbal medicine used worldwide for managing GI tract disturbances. However, its role in gastric cancer is sparingly known. This study ensures the standardization of gastric cancer by the induction of N-nitroso N-methyl Urea (MNU) and to determine the role of the aqueous extract of ginger (AGE) in MNU-induced gastric cancer in albino Wistar rats. Accordingly, the anticancer potential of AGE and its possible mode of action were assessed on rats exposed to MNU, by various biochemical and molecular assays. As evidenced by the extent of lipid peroxidation, gastrin levels and histopathological sections in MNU-induced cancerous lesions at 8 wk which was stabilized at 16 wk confirming the induction of gastric carcinoma by the chemical carcinogen. Further, results revealed that AGE alleviated the oxidative stress as evidenced by the stomach antioxidant enzymes (SOD, catalase, GPx, and GR), markers of oxidative stress (TRx, GRx) and Gastrin, a specific marker for gastric cancer and a decreased level of pro-inflammatory markers (NF-kB, TNF-α, IL-6, PGE2) which was further confirmed by histopathological analysis. AGE is responsible to mitigate oxidative stress and inflammation related to gastric cancer and could be used as a potential dietary intervention in gastric cancer therapy.


Subject(s)
Alkylating Agents/toxicity , Methylnitrosourea/toxicity , Neoplasms, Experimental/drug therapy , Phytotherapy/methods , Plant Extracts/pharmacology , Stomach Neoplasms/drug therapy , Zingiber officinale/chemistry , Animals , Disease Models, Animal , Glutathione Peroxidase/metabolism , Humans , Lipid Peroxidation/drug effects , Male , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Oxidative Stress/drug effects , Palliative Care , Rats , Rats, Wistar , Stomach Neoplasms/chemically induced , Stomach Neoplasms/pathology
11.
Braz. j. biol ; 79(4): 629-638, Nov. 2019. tab, graf
Article in English | LILACS | ID: biblio-1001489

ABSTRACT

Abstract Background Hepatocellular carcinoma is the most frequent primary malignancy of liver and accounts for as many as one million deaths worldwide in a year. Objectives The aim of the present study was to evaluate the anti-cancerous efficiency of Bergenia ciliata rhizome against diethylnitrosoamine induced hepatocarcinogenesis in Balb C mice. Methods One percent diethylnitrosoamine was prepared by using 99 ml of normal saline NaCl (0.9 percent) solution to which was added 1 ml of concentrated diethylnitrosoamine (DEN) solution (0.01 μg/μl). Extract of Bergenia ciliata was prepared by maceration technique. Mice were classified into four groups as follows: Group 1 a control group (N=7) received saline solution (3.5 μl/mg), group 2 (N=14) received diethylnitrosoamine (3.5 μl/mg) intraperitoneally once in a week for eight consecutive weeks, group 3 (N=7) received plant extract (150 mg/kg (Body weight)) once in a week, while group 4 (N=7) was given combination of diethylnitrosoamine (3.5 μl/mg) and plant extract (150 mg/kg (Body weight)). After eight weeks of DEN induction group 2 mice were divided into two subgroups containing seven mice each, subgroup 1 was sacrificed while subgroup 2 was treated with plant extract (150 mg/kg (Body weight)) once in a week for eight consecutive weeks. Results The model of DEN injected hepatocellular carcinomic (HCC) mice elicited significant decline in levels of albumin with concomitant significant elevations in tumor markers aspartate aminotransferase, alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. The intraperitoneal administration of B. ciliata as a protective agent, produced significant increase in albumin levels with significant decrease in the levels of tumor markers aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. Conclusion Bergenia ciliata has potent antioxidant activity, radical scavenging capacity and anticancerous properties. Bergenia ciliata extracts may provide a basis for development of anti-cancerous drug.


Resumo Antecedentes O carcinoma hepatocelular é a neoplasia primária mais frequente do fígado e é responsável por até um milhão de mortes em todo o mundo em um ano. Objetivos O objetivo do presente estudo foi avaliar a eficiência anticancerígena do rizoma de Bergenia ciliata contra a hepatocarcinogênese induzida por dietilnitrosoamina em camundongos balb c. Métodos Um por cento de dietilnitrosoamina foi preparado usando 99 ml de solução salina normal (0,9 por cento) à qual foi adicionado 1 ml de solução concentrada de dietilnitrosoamina (DEN) (0,01 μg / μl). O extrato de Bergenia ciliata foi preparado pela técnica de maceração. Os ratos foram classificados em quatro grupos: Grupo 1 grupo controle (N = 7) recebeu solução salina (3,5 mL / mg), grupo 2 (N = 14) recebeu dietilnitrosoamina (3,5 mL / mg) por via intraperitoneal uma vez por semana para oito semanas consecutivas, o grupo 3 (N = 7) recebeu extrato vegetal (150 mg / kg (peso corporal)) uma vez por semana, enquanto o grupo 4 (N = 7) recebeu combinação de dietilnitrosoamina (3,5 μl / mg) e extrato (150 mg / kg (peso corporal). Após oito semanas do grupo de indução DEN 2 ratos foram divididos em dois subgrupos contendo sete ratos cada, subgrupo 1 foi sacrificado enquanto subgrupo 2 foi tratado com extrato vegetal (150 mg / kg)) uma vez por semana durante oito semanas consecutivas. Resultados O modelo de camundongos hepatocelulares carcinômicos (CHC) injetados com DEN provocou declínio significativo nos níveis de albumina com elevações significativas concomitantes nos marcadores tumorais: aspartato aminotransferase, alanina aminotransferase (ALT), lactato desidrogenase (LDH), proteína alfa feto (AFP), gama glutamiltransferase (Y-GT), 5 nucleotidase (5NT), glicose-6-fosfato ehidrogenase (G6PDH) e bilirrubina. A administração intraperitoneal de B. ciliata como agente protetor produziu um aumento significativo nos níveis de albumina com uma diminuição significativa nos níveis dos marcadores tumorais: aspartato aminotransferase, alanina aminotransferase (ALT), lactato desidrogenase (LDH), proteína alfa feto (AFP), gama glutamiltransferase (Y-GT), 5 nucleotidase (5NT), glicose-6-fosfato desidrogenase (G6PDH) e bilirrubina. Conclusão Bergenia ciliata possui atividade antioxidante potente, capacidade de eliminação de radicais livres e propriedades anticancerígenas. Extratos de Bergenia ciliata podem fornecer uma base para o desenvolvimento de drogas anti-cancerígenas.


Subject(s)
Animals , Male , Rats , Carcinoma, Hepatocellular/chemically induced , Carcinoma, Hepatocellular/pathology , Diethylnitrosamine/pharmacology , Liver Neoplasms/chemically induced , Liver Neoplasms/pathology , Neoplasms, Experimental/chemically induced , Plant Extracts/pharmacology , Saxifragaceae , Alkylating Agents/pharmacology , Mice, Inbred BALB C
12.
Sci Rep ; 9(1): 11636, 2019 08 12.
Article in English | MEDLINE | ID: mdl-31406187

ABSTRACT

A large number of basic researches and observational studies suggested the cancer preventive activity of vitamin E, but large-scale human intervention trials have yielded disappointing results and actually showed a higher incidence of prostate cancer although the mechanisms underlying the increased risk remain largely unknown. Here we show through in vitro and in vivo studies that vitamin E produces a marked inductive effect on carcinogen-bioactivating enzymes and a pro-oxidant status promoting both DNA damage and cell transformation frequency. First, we found that vitamin E in the human prostate epithelial RWPE-1 cell line has the remarkable ability to upregulate the expression of various phase-I activating cytochrome P450 (CYP) enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), giving rise to supraphysiological levels of reactive oxygen species. Furthermore, our rat model confirmed that vitamin E in the prostate has a powerful booster effect on CYP enzymes associated with the generation of oxidative stress, thereby favoring lipid-derived electrophile spread that covalently modifies proteins. We show that vitamin E not only causes DNA damage but also promotes cell transformation frequency induced by the PAH-prototype benzo[a]pyrene. Our findings might explain why dietary supplementation with vitamin E increases the prostate cancer risk among healthy men.


Subject(s)
Cell Transformation, Neoplastic/chemically induced , Cytochrome P-450 Enzyme System/metabolism , Dietary Supplements/toxicity , Neoplasms, Experimental/chemically induced , Prostatic Neoplasms/chemically induced , Vitamin E/toxicity , 3T3 Cells , Animals , Benzo(a)pyrene/toxicity , Carcinogens/toxicity , Cell Line , Cell Transformation, Neoplastic/genetics , DNA Damage/drug effects , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Humans , Lipid Peroxidation/drug effects , Male , Mice , Micronuclei, Chromosome-Defective/chemically induced , Neoplasms, Experimental/genetics , Neoplasms, Experimental/pathology , Oxidative Stress/drug effects , Prostate/cytology , Prostate/pathology , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Rats , Reactive Oxygen Species/metabolism , Up-Regulation/drug effects , Vitamin E/administration & dosage
13.
Arch Dermatol Res ; 311(8): 595-605, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31165240

ABSTRACT

Wnt pathway plays an important role in controlling metabolism in cancer cells. It acts as positive modulator for both cell inflammation, through activation of NFκB, and fibrosis, through activation of TGF-ß. Therefore, the aim of this study is to investigate the therapeutic effects of blocking Wnt pathway by IWP12 on skin cancer by studying its effects on skin cancer-induced inflammation and fibrosis in a mice model of skin cancer. Skin cancer was induced by application of 7,12-dimethylbenz[a]anthracene (DMBA) and croton oil on the dorsal skin of mice. Dorsal skin was removed for estimation of gene and protein expression of Wnt, ß-catenin, SMAD, TGF-ß, NFκB, TNF-α, IL-4 and IL-10. Part of the skin is stained with hematoxylin/eosin for assessment of cell structure. Treatment of mice with IWP12 completely blocked Wnt in skin cancer mice without affecting the control mice. Skin of tumorigenic mice showed marked skin hyperkeratosis, parakeratosis, acanthosis and dysplasia. Treatment with IWP12 markedly attenuated epidermal atypia and hyperplasia. In addition, IWP12 reduced expression of ß-catenin, SMAD, TGF-ß, NFκB and TNF-α associated with increase in the expression of IL-4 and IL-10. In conclusion, blocking Wnt production ameliorated skin cancer via blocking pro-inflammatory cytokines and enhancing the anti-inflammatory cytokines. Moreover, blocking Wnt attenuated skin cancer-induced activation of fibrosis pathway.


Subject(s)
Antineoplastic Agents/pharmacology , Carcinogenesis/drug effects , Skin Neoplasms/drug therapy , Wnt Proteins/antagonists & inhibitors , Wnt Signaling Pathway/drug effects , 9,10-Dimethyl-1,2-benzanthracene/toxicity , Animals , Antineoplastic Agents/therapeutic use , Carcinogenesis/chemically induced , Croton Oil/toxicity , Cytokines/metabolism , Drug Screening Assays, Antitumor , Epidermis/drug effects , Epidermis/pathology , Fibrosis , Gene Expression Regulation, Neoplastic/drug effects , Humans , Mice , NF-kappa B/metabolism , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/pathology , Skin Neoplasms/chemically induced , Skin Neoplasms/pathology , Wnt Proteins/metabolism
14.
Braz J Biol ; 79(4): 629-638, 2019.
Article in English | MEDLINE | ID: mdl-31017181

ABSTRACT

BACKGROUND: Hepatocellular carcinoma is the most frequent primary malignancy of liver and accounts for as many as one million deaths worldwide in a year. OBJECTIVES: The aim of the present study was to evaluate the anti-cancerous efficiency of Bergenia ciliata rhizome against diethylnitrosoamine induced hepatocarcinogenesis in Balb C mice. METHODS: One percent diethylnitrosoamine was prepared by using 99 ml of normal saline NaCl (0.9 percent) solution to which was added 1 ml of concentrated diethylnitrosoamine (DEN) solution (0.01 µg/µl). Extract of Bergenia ciliata was prepared by maceration technique. Mice were classified into four groups as follows: Group 1 a control group (N=7) received saline solution (3.5 µl/mg), group 2 (N=14) received diethylnitrosoamine (3.5 µl/mg) intraperitoneally once in a week for eight consecutive weeks, group 3 (N=7) received plant extract (150 mg/kg (Body weight)) once in a week, while group 4 (N=7) was given combination of diethylnitrosoamine (3.5 µl/mg) and plant extract (150 mg/kg (Body weight)). After eight weeks of DEN induction group 2 mice were divided into two subgroups containing seven mice each, subgroup 1 was sacrificed while subgroup 2 was treated with plant extract (150 mg/kg (Body weight)) once in a week for eight consecutive weeks. RESULTS: The model of DEN injected hepatocellular carcinomic (HCC) mice elicited significant decline in levels of albumin with concomitant significant elevations in tumor markers aspartate aminotransferase, alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. The intraperitoneal administration of B. ciliata as a protective agent, produced significant increase in albumin levels with significant decrease in the levels of tumor markers aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. CONCLUSION: Bergenia ciliata has potent antioxidant activity, radical scavenging capacity and anticancerous properties. Bergenia ciliata extracts may provide a basis for development of anti-cancerous drug.


Subject(s)
Carcinoma, Hepatocellular , Diethylnitrosamine/pharmacology , Liver Neoplasms , Neoplasms, Experimental/chemically induced , Plant Extracts/pharmacology , Saxifragaceae , Alkylating Agents/pharmacology , Animals , Carcinoma, Hepatocellular/chemically induced , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/chemically induced , Liver Neoplasms/pathology , Male , Mice , Mice, Inbred BALB C
15.
Eur J Cancer Prev ; 28(5): 383-389, 2019 09.
Article in English | MEDLINE | ID: mdl-30234553

ABSTRACT

Multicomponent therapy has gained interest for its potential to synergize and subsequently lower the effective dose of each constituent required to reduce colon cancer risk. We have previously showed that rapidly cycling Lgr5 stem cells are exquisitely sensitive to extrinsic dietary factors that modulate colon cancer risk. In the present study, we quantified the dose-dependent synergistic properties of dietary n-3 polyunsaturated fatty acids (PUFA) and curcumin (Cur) to promote targeted apoptotic deletion of damaged colonic Lgr5 stem cells. For this purpose, both heterogeneous bulk colonocytes and Lgr5 stem cells were isolated from Lgr5-EGFP-IRES-CreER knock-in mice injected with azoxymethane (AOM). Isolated cells were analyzed for DNA damage (γH2AX), apoptosis (cleaved caspase-3), and targeted apoptosis (both γH2AX and cleaved caspase-3) at 12 h post-AOM injection. Comparison of the percentage of targeted apoptosis in Lgr5 stem cells (GFP) across a broad bioactive dose-range revealed an ED50 of 16.0 mg/day n-3 PUFA + 15.9 mg/day Cur. This corresponded to a human equivalent dose of 3.0 g n-3 PUFA + 3.0 g Cur. In summary, our results provide evidence that a low dose (n-3 PUFA + Cur) combination diet reduces AOM-induced DNA damage in Lgr5 stem cells and enhances targeted apoptosis of DNA-damaged cells, implying that a lower human equivalent dose can be utilized in future human clinical trials.


Subject(s)
Colonic Neoplasms/prevention & control , Curcumin/administration & dosage , Fatty Acids, Omega-3/administration & dosage , Neoplastic Stem Cells/drug effects , Receptors, G-Protein-Coupled/metabolism , Animals , Apoptosis/drug effects , Azoxymethane/toxicity , Carcinogens/toxicity , Cell Proliferation/drug effects , Cell Transformation, Neoplastic/drug effects , Cell Transformation, Neoplastic/pathology , Colon/cytology , Colon/drug effects , Colon/pathology , Colonic Neoplasms/chemically induced , Colonic Neoplasms/pathology , Dietary Supplements , Dose-Response Relationship, Drug , Female , Gene Knock-In Techniques , Humans , Intestinal Mucosa/cytology , Intestinal Mucosa/drug effects , Intestinal Mucosa/pathology , Male , Mice , Mice, Transgenic , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Neoplasms, Experimental/prevention & control , Neoplastic Stem Cells/pathology , Receptors, G-Protein-Coupled/genetics
16.
BMC Cancer ; 18(1): 1111, 2018 Nov 13.
Article in English | MEDLINE | ID: mdl-30424722

ABSTRACT

BACKGROUND: Colorectal cancer has been found to be attenuated either with prophylactic manipulation of gut microbiome with probiotics or celecoxib, a non-steroidal anti-inflammatory drug mainly by suppressing early pro-carcinogenic markers in various experimental studies. Therefore, the present study was designed to assess the prophylactic potential of combinatorial administration of probiotics (Lactobacillus rhamnosus GG, Lactobacillus acidophilus) and celecoxib in experimental colon carcinogenesis. METHODS: Six groups of Spraugue Dawely rats received probiotics L.rhamnosus GG or/and L.acidophilus in combination with celecoxib one week prior to the inducement of tumor by 1,2-dimethylhydrazine (DMH) and the treatment continued for 18 weeks. Prophylactic potentials of probiotics and celecoxib were determined by employing various methods such as tumor incidence, tumor burden, tumor multiplicity, apoptosis, caspase activity, expression of proto-oncogene K-ras and tumor suppressor p53 gene in colonic tumors. RESULTS: Interestingly, it was found that one week prior supplementation of both probiotics and celecoxib reduced tumor burden, tumor multiplicity, down-regulated the expression of anti-apoptotic Bcl-2, proto-oncogene K-ras and up-regulated pro-apoptotic Bax as well as tumor suppressor p53 in L.rhamnosus GG + celecoxib+DMH animals compared with counter controls and DMH-treated. CONCLUSIONS: It can be concluded that such combinatorial approach may be useful in reducing the burden and severity of disease in highly susceptible individuals but needs to be validated clinically.


Subject(s)
Celecoxib/pharmacology , Colorectal Neoplasms/diet therapy , Lacticaseibacillus rhamnosus , Lactobacillus acidophilus , Probiotics/administration & dosage , 1,2-Dimethylhydrazine/toxicity , Animals , Apoptosis/drug effects , Carcinogenesis/drug effects , Carcinogenesis/pathology , Carcinogens/toxicity , Celecoxib/therapeutic use , Colon/drug effects , Colon/pathology , Colorectal Neoplasms/chemically induced , Colorectal Neoplasms/pathology , Colorectal Neoplasms/prevention & control , Combined Modality Therapy/methods , Down-Regulation/drug effects , Drug Evaluation, Preclinical , Gene Expression Regulation, Neoplastic/drug effects , Humans , Male , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/diet therapy , Neoplasms, Experimental/prevention & control , Proto-Oncogene Mas , Rats , Rats, Sprague-Dawley , Treatment Outcome , Up-Regulation/drug effects , bcl-2-Associated X Protein/metabolism
17.
J Trace Elem Med Biol ; 47: 21-30, 2018 May.
Article in English | MEDLINE | ID: mdl-29544804

ABSTRACT

Zinc is a trace element widely known for its marked antioxidant properties. To gain more insight into the site- and time- specific mechanisms by which it induces chemoprevention, this study was elaborated over a pre-cancerous model of colon carcinogenesis. Colon cancer was induced by 1,2-dimethylhydrazine (DMH) in mice (20 mg/kg for 2 weeks) and groups of animals were supplemented with or without zinc sulfate (ZnSO4, 200 mg/L) in drinking water for 4, 10 or 14 weeks. Colon tissues were collected for pathological observation, analyzing aberrant crypt (AC) and aberrant crypt foci (ACF) formations, multiplicity and distribution. Similarly, histological assessment and mucin production, as well as oxidative stress markers estimation was performed for the different groups. Results showed a significant increase in ACF and AC numbers, ACF multiplicity and demonstrated stronger distal occurrence than in the proximal after DHM administration. Histopathological analysis presented marked structural alterations and mucin loss in the distal than the proximal colons. A significant increase in myeloperoxidase (MPO), nitric oxide (NO), L-ornithine and malondialdehyde (MDA) levels was observed followed by a significant decrease in antioxidant markers (superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH)). Oral ZnSO4 supplementation (continuous or partial) induced significant decrease in ACF, AC numbers and multiplicity, restored histological architecture and mucin production, and a significant decrease in proinflammatory markers while it reduced antioxidants to normal levels. From this study, insight was obtained on the use of ZnSO4 as a chemopreventive agent and shed light on its potential, as a supplement in nutraceutical approaches.


Subject(s)
Aberrant Crypt Foci/drug therapy , Colonic Neoplasms/drug therapy , Zinc Sulfate/pharmacology , 1,2-Dimethylhydrazine/toxicity , Aberrant Crypt Foci/chemically induced , Aberrant Crypt Foci/metabolism , Animals , Anticarcinogenic Agents/pharmacology , Antioxidants/metabolism , Colonic Neoplasms/chemically induced , Colonic Neoplasms/metabolism , Enzymes/metabolism , Mice , Neoplasms, Experimental/chemically induced , Oxidative Stress/drug effects , Precancerous Conditions/chemically induced , Precancerous Conditions/drug therapy , Precancerous Conditions/pathology
18.
Sci Rep ; 8(1): 1682, 2018 01 26.
Article in English | MEDLINE | ID: mdl-29374195

ABSTRACT

The present study was designed to investigate if elevated copper level can be targeted to enhance the efficacy of a significant anticancer drug, imatinib (ITB). The antineoplastic activity of this drug was assessed in the HepG2, HEK-293, MCF-7 and MDA-MD-231 cells targeting elevated copper level as their common drug target. The cell lines were treated with the different doses of copper chloride (Cu II) and disulfiram (DSF) alone as well as in their combinations with the drug for 24 h in standard culture medium and conditions. The treated cells were subjected to various assays including MTT, PARP, p-53, caspase-7, caspase-3, LDH and single cell electrophoresis. The study shows that DSF and Cu (II) synergizes the anticancer activity of ITB to a significant extent in a dose-specific way as evidenced by the combinations treated groups. Furthermore, the same treatment strategy was employed in cancer-induced rats in which the combinations of ITB-DSF and ITB-Cu II showed enhanced antineoplastic activity as compared to ITB alone. However, DSF was more effective than Cu (II) as an adjuvant to the drug. Hence, restrained manipulation of copper level in tumor cells can orchestrate the redox and molecular dispositions inside the cells favoring the induction of apoptosis.


Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacology , Copper/metabolism , Drug Synergism , Imatinib Mesylate/administration & dosage , Imatinib Mesylate/pharmacology , Neoplasms, Experimental/drug therapy , Animals , Cell Survival/drug effects , Chemotherapy, Adjuvant/methods , Disulfiram/metabolism , Metabolism/drug effects , Neoplasms, Experimental/chemically induced , Rats , Treatment Outcome
19.
Eur J Cancer Prev ; 27(2): 110-117, 2018 03.
Article in English | MEDLINE | ID: mdl-27926538

ABSTRACT

This study focused on the chemopreventive effects of Spirogyra neglecta extract (SNE) and dried S. neglecta mixed diet on the early stages of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats. Male Wistar rats were injected with DMH to initiate aberrant crypt foci (ACF) formation. In the initiation stage, SNE significantly decreased the number of ACF in the colon of DMH-treated rats. Rats that received a low dose of SNE showed enhanced activity of several detoxifying and antioxidant enzymes. In the postinitiation stage, a low dose of SNE significantly decreased the number of ACF in the colon of DMH-treated rats. It significantly reduced the number of proliferating cell nuclear antigen-positive cells and increased the number of apoptotic cells in colonic crypts. S. neglecta thus inhibited the development of the early stages of DMH-induced colon carcinogenesis in rats by modulation of xenobiotic metabolizing enzymes and inhibition of cell proliferation as well as induction of apoptosis.


Subject(s)
Aberrant Crypt Foci/prevention & control , Anticarcinogenic Agents/therapeutic use , Colonic Neoplasms/prevention & control , Plant Extracts/therapeutic use , Spirogyra/chemistry , 1,2-Dimethylhydrazine/toxicity , Aberrant Crypt Foci/chemically induced , Aberrant Crypt Foci/pathology , Animals , Anticarcinogenic Agents/pharmacology , Apoptosis/drug effects , Aryl Hydrocarbon Hydroxylases/metabolism , Carcinogens/toxicity , Cell Proliferation/drug effects , Colon/drug effects , Colon/pathology , Colonic Neoplasms/chemically induced , Colonic Neoplasms/pathology , Humans , Male , Neoplasm Staging , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/prevention & control , Plant Extracts/pharmacology , Rats , Rats, Wistar , Treatment Outcome
20.
Crit Rev Toxicol ; 48(2): 121-142, 2018 02.
Article in English | MEDLINE | ID: mdl-29095660

ABSTRACT

When assessing cancer hazard and risk associated with a complex petroleum substance, like bitumen emissions, there are often conflicting results related to human, animal and mechanistic studies. Validation of the complex composition to assure that it matches real-world exposures and control of confounders are pivotal factors in study design to allow the necessary read-across during assessments. Several key studies on bitumen emissions in two-year dermal cancer assays reported variable outcomes ranging from high cancer incidence to no cancer incidence. Here, we synthesize findings from published studies to explain the differences and discuss critical factors in cancer hazard evaluation for complex petroleum substances. Using these critical factors, we reviewed relevant human genetic toxicity, mammalian toxicity and mechanistic studies with bitumen to understand the divergence in results. We assess the most reliable and scientifically supported information on the potential carcinogenic hazards of bitumen emissions and comment on quality and completeness of data. Human hazard data are typically considered highest priority because they eliminate the need for interspecies extrapolation and reduce the range of high -to low-dose extrapolation during the risk assessment process. Finally, two well-conducted comprehensive animal studies are discussed that have well-defined test material, exposure concentration and composition representative of worker exposure, evidence of systemic uptake, no confounding exposures and provide consistency across all elements within both studies. Studies that allow effective read-across from human, animal and mechanistic components, control for confounders and are well-validated analytically against workplace exposures, provide the strongest evidence base for evaluating cancer hazard.


Subject(s)
Carcinogens, Environmental/toxicity , Environmental Exposure/adverse effects , Hydrocarbons/toxicity , Neoplasms/chemically induced , Air Pollutants/chemistry , Air Pollutants/toxicity , Animals , Carcinogens, Environmental/chemistry , Humans , Hydrocarbons/chemistry , Neoplasms, Experimental/chemically induced , Petroleum/toxicity , Toxicity Tests/methods
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