title: Modulation of miR-203 and its regulators as a function of time during the development of 7, 12 dimethylbenz [a] anthracene induced mouse skin tumors in presence or absence of the antitumor agents.
abstract: We investigated the chemopreventive effects of naturally occurring compounds like butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) individually or in combination in 7, 12-dimethylbenz [a] anthracene (DMBA) treated mouse skin at 4 and 16 weeks, the time before and after the tumor development. DMBA application did not show any skin tumors at 4 weeks but well defined tumors appeared at 16 weeks. BA, NA or CAG prevented the tumor development significantly but the protection was highly enhanced when all these compounds were given together. In order to see the molecular changes progressing with tumors, we showed the downregulation of tumor suppressor miR-203 at 16 weeks and upregulation of histone deacetylases (HDAC), DNA methyltransferase, promoter methylation of miR-203 at 4 or 16 weeks. Regulators of micro RNA biogenesis such as DICER1 and Ago2 were also deregulated by DMBA. Proto-oncogene c-myc and BMI1 were upregulated and tumor suppressor gene p16 was downregulated by DMBA as a function of time. Effects of BA, NA or CAG were more pronounced after 16 weeks as compared to 4 weeks in preventing the tumor development and altered gene expression. Concomitant administration of BA, NA and CAG tried to prevent these alterations more effectively than that of individual compound possibly by regulating miR-203 status through epigenetic or biogenetic modulations before and after the tumor development. Study provides a rationale for chemoprevention by combination of different compounds targeting miR-203.
authors.affiliation: Environmental Carcinogenesis Division, CSIR-Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226001 India.
authors.forename: Prakash
authors.initials: P
authors.lastname: Tiwari
authors.affiliation: Environmental Carcinogenesis Division, CSIR-Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226001 India. Electronic address: krishnag522@yahoo.co.in.
authors.forename: Krishna P
authors.initials: KP
authors.lastname: Gupta
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D019175:DNA Methylation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D006655:Histone Deacetylases / Q000096:biosynthesis / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012878:Skin Neoplasms / Q000139:chemically induced* / Q000378:metabolism* / Q000517:prevention & control; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; C575934:MIRN203 microRNA, mouse; D035683:MicroRNAs; D015127:9,10-Dimethyl-1,2-benzanthracene; D006655:Histone Deacetylases
keywords: Chemoprevention; DICER1; DMBA; Epigenetics; Skin tumor; miR-203