title: Epigenetics and miRNA as predictive markers and targets for lung cancer chemotherapy.
abstract: Lung cancer cells show inherent and acquired resistance to chemotherapy. The lack of good predictive markers/novel targets and the incomplete understanding of the mechanisms of resistance limit the success of lung cancer response to chemotherapy. In the present study, we used an isogenic pair of lung adenocarcinoma cell lines; A549 (wild-type) and A549DOX11 (doxorubicin resistant) to study the role of epigenetics and miRNA in resistance/response of non-small cell lung cancer (NSCLC) cells to doxorubicin. Our results demonstrate differential expression of epigenetic markers whereby the level of HDACs 1, 2, 3 and4, DNA methyltransferase, acetylated H2B and acetylated H3 were lower in A549DOX11 compared to A549 cells. Fourteen miRNAs were dys-regulated in A549DOX11 cells compared to A549 cells, of these 14 miRNAs, 4 (has-mir-1973, 494, 4286 and 29b-3p) have shown 2.99 - 4.44 fold increase in their expression. This was associated with reduced apoptosis and higher resistance of A549DOX11cells to doxorubicin and etoposide. Sequential treatment with the epigenetic modifiers trichostatin A or 5-aza-2'-deoxycytidine followed by doxorubicin resulted in: (i) enhanced sensitivity of both cell lines to doxorubicin especially at low concentrations, (ii) enhanced doxorubicin-induced DNA damage in both cell lines, (iii) dysregulation of some miRNAs in A549 cells. In conclusion, A549DOX11 cells resistant to DNA damaging drugs have epigenetic profile and miRNA expression different from the sensitive cells. Moreover, epigenetic modifiers may reverse the resistance of certain NSCLC cells to DNA damaging agents by enhancing induction of DNA damage. This may open the door for using epigenetic profile/miRNA expression of some cancer cells as resistance markers/targets to improve response of resistant cells to doxorubicin and for the use of combination doxorubicin/epigenetic modifiers to reduce doxorubicin toxicity.
authors.affiliation: a College of Pharmacy; University of Sharjah ; Sharjah , United Arab Emirates.
authors.forename: Raafat A
authors.initials: RA
authors.lastname: El-Awady
authors.forename: Fatema
authors.initials: F
authors.lastname: Hersi
authors.forename: Hala
authors.initials: H
authors.lastname: Al-Tunaiji
authors.forename: Ekram M
authors.initials: EM
authors.lastname: Saleh
authors.forename: Abdel-Hady A
authors.initials: AH
authors.lastname: Abdel-Wahab
authors.forename: Amer
authors.initials: A
authors.lastname: Al Homssi
authors.forename: Mousa
authors.initials: M
authors.lastname: Suhail
authors.forename: Ahmed
authors.initials: A
authors.lastname: El-Serafi
authors.forename: Taleb
authors.initials: T
authors.lastname: Al-Tel
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics; D015254:DNA Modification Methylases / Q000235:genetics / Q000378:metabolism; D000077209:Decitabine; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000187:drug effects / Q000235:genetics*; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000903:Antibiotics, Antineoplastic; D014408:Biomarkers, Tumor; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D035683:MicroRNAs; C012589:trichostatin A; D000077209:Decitabine; D004317:Doxorubicin; D015254:DNA Modification Methylases; D006655:Histone Deacetylases; D001374:Azacitidine
keywords: 5-aza-2′-deoxycytidine; 5AZA, 5-aza-2′-deoxycytidine; 5mc, 5-methyl cytosine; BSA, bovine serum albumin; DMSO, dimethyl sulfoxide; DNMT, DNA methyltransferase; HAT, histone acetyl transferase; HDAC; HDAC, histone deacetylase; NSCLC, non-small cell lung cancer; PBS, phosphate-buffered saline; SCLC, small-cell lung cancer; TSA, trichostatin A; doxorubicin; epigenetics; miRNA; trichostatin A