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Epigenetic Modifications and Accumulation of DNA Double-Strand Breaks in Oral Lichen Planus Lesions Presenting Poor Response to Therapy.

Dillenburg CS, Martins MA, Almeida LO, Meurer L, Squarize CH, Martins MD, Castilho RM - Medicine (Baltimore) (2015)

Bottom Line: Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive.We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci.Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Oral Pathology (CSD, MDM), School of Dentistry; Department of Oral Medicine (MATM), Hospital de Clínicas de Porto Alegre (HCPA/UFRGS); Department of Pathology (LM), School of Medicine, Hospital de Clínicas de Porto Alegre (HCPA/UFRGS), Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; and Laboratory of Epithelial Biology (CSD, MATM, LOA, CHS, MDM, RMC), Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA.

ABSTRACT
Epigenetics refers to changes in cell characteristics that occur independently of modifications to the deoxyribonucleic acid (DNA) sequence. Alterations mediated by epigenetic mechanisms are important factors in cancer progression. Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive. We examined alterations in chromatin acetylation in oral lichen planus (OLP) with distinct clinical behavior and compared the alterations to the levels of DNA double-strand breaks (DSBs). We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci. Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy. Similar to H3K9ac, patients who responded poorly to therapy had increased accumulation of DNA DSB, indicating genomic instability. These findings suggest that histone modifications occur in OLP, and H3K9ac and γH2AX histones may serve as epigenetic markers for OLP recurrence.

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Acetylation of histone 3 correlates to poor response to therapy. (A) H&E staining of OLP patients (upper panel—100× magnification; lower panel—400× magnification). Modification in basal cell morphology and nuclear shape is evident in all OLP types in areas with different degree of exocytosis (arrows). Note that all OLP lesions present focal areas of well-preserved basal architecture (arrowhead). (B) Immunofluorescence staining of well-preserved basal layers demonstrates increased acetylation of histone 3 in the nucleus of Types II and III OLP patients (green labeling). Vimentin staining (red staining) was used to differentiate the epithelial from mesenchymal tissues. (C) Diamond shape represents each patient distributed by OLP response to therapy (OLP type) and histone 3 acetylation. Type I patients have an average ac.H3 intensity of 0.61 compared to 2.07 and 2.62 in Types II and III patients, respectively (error bar, SEM; P = 0.15, ∗∗∗P<0.001). H&E = hematoxylin and eosin, OLP = oral lichen planus, SEM = standard error of the mean.
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Figure 2: Acetylation of histone 3 correlates to poor response to therapy. (A) H&E staining of OLP patients (upper panel—100× magnification; lower panel—400× magnification). Modification in basal cell morphology and nuclear shape is evident in all OLP types in areas with different degree of exocytosis (arrows). Note that all OLP lesions present focal areas of well-preserved basal architecture (arrowhead). (B) Immunofluorescence staining of well-preserved basal layers demonstrates increased acetylation of histone 3 in the nucleus of Types II and III OLP patients (green labeling). Vimentin staining (red staining) was used to differentiate the epithelial from mesenchymal tissues. (C) Diamond shape represents each patient distributed by OLP response to therapy (OLP type) and histone 3 acetylation. Type I patients have an average ac.H3 intensity of 0.61 compared to 2.07 and 2.62 in Types II and III patients, respectively (error bar, SEM; P = 0.15, ∗∗∗P<0.001). H&E = hematoxylin and eosin, OLP = oral lichen planus, SEM = standard error of the mean.

Mentions: We next reevaluated the histological samples of OLP patients in light of their responsiveness to therapy and histone modifications. Emerging evidences indicate the involvement of histone modifications in the inflammatory conditions such as rheumatoid arthritis, chronic obstructive pulmonary disease, and severe asthma.35,36 Functional acetylation of histone H3 at Lys 9 results in chromatin decondensation, chromatin assembly, and gene activation thereby being considered a marker of transcriptionally active chromatin.37–39 Here we decided to explore the transcriptional activity of OLP in patients who had different responses to therapy (Type I, Type II, and Type III), using a H3K9ac antibody. Interestingly, we observed high levels of histone H3 acetylation (Lys9) in the basal layer of tissue samples from Types II and III patients compared to Type I patients (Figure 2B). The correlation between increased acetylation levels of histone H3 (Lys9) and poor response to therapy is observed in Types II and III patients (Figure 2C) (∗∗∗P < 0.001).


Epigenetic Modifications and Accumulation of DNA Double-Strand Breaks in Oral Lichen Planus Lesions Presenting Poor Response to Therapy.

Dillenburg CS, Martins MA, Almeida LO, Meurer L, Squarize CH, Martins MD, Castilho RM - Medicine (Baltimore) (2015)

Acetylation of histone 3 correlates to poor response to therapy. (A) H&E staining of OLP patients (upper panel—100× magnification; lower panel—400× magnification). Modification in basal cell morphology and nuclear shape is evident in all OLP types in areas with different degree of exocytosis (arrows). Note that all OLP lesions present focal areas of well-preserved basal architecture (arrowhead). (B) Immunofluorescence staining of well-preserved basal layers demonstrates increased acetylation of histone 3 in the nucleus of Types II and III OLP patients (green labeling). Vimentin staining (red staining) was used to differentiate the epithelial from mesenchymal tissues. (C) Diamond shape represents each patient distributed by OLP response to therapy (OLP type) and histone 3 acetylation. Type I patients have an average ac.H3 intensity of 0.61 compared to 2.07 and 2.62 in Types II and III patients, respectively (error bar, SEM; P = 0.15, ∗∗∗P<0.001). H&E = hematoxylin and eosin, OLP = oral lichen planus, SEM = standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554108&req=5

Figure 2: Acetylation of histone 3 correlates to poor response to therapy. (A) H&E staining of OLP patients (upper panel—100× magnification; lower panel—400× magnification). Modification in basal cell morphology and nuclear shape is evident in all OLP types in areas with different degree of exocytosis (arrows). Note that all OLP lesions present focal areas of well-preserved basal architecture (arrowhead). (B) Immunofluorescence staining of well-preserved basal layers demonstrates increased acetylation of histone 3 in the nucleus of Types II and III OLP patients (green labeling). Vimentin staining (red staining) was used to differentiate the epithelial from mesenchymal tissues. (C) Diamond shape represents each patient distributed by OLP response to therapy (OLP type) and histone 3 acetylation. Type I patients have an average ac.H3 intensity of 0.61 compared to 2.07 and 2.62 in Types II and III patients, respectively (error bar, SEM; P = 0.15, ∗∗∗P<0.001). H&E = hematoxylin and eosin, OLP = oral lichen planus, SEM = standard error of the mean.
Mentions: We next reevaluated the histological samples of OLP patients in light of their responsiveness to therapy and histone modifications. Emerging evidences indicate the involvement of histone modifications in the inflammatory conditions such as rheumatoid arthritis, chronic obstructive pulmonary disease, and severe asthma.35,36 Functional acetylation of histone H3 at Lys 9 results in chromatin decondensation, chromatin assembly, and gene activation thereby being considered a marker of transcriptionally active chromatin.37–39 Here we decided to explore the transcriptional activity of OLP in patients who had different responses to therapy (Type I, Type II, and Type III), using a H3K9ac antibody. Interestingly, we observed high levels of histone H3 acetylation (Lys9) in the basal layer of tissue samples from Types II and III patients compared to Type I patients (Figure 2B). The correlation between increased acetylation levels of histone H3 (Lys9) and poor response to therapy is observed in Types II and III patients (Figure 2C) (∗∗∗P < 0.001).

Bottom Line: Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive.We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci.Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Oral Pathology (CSD, MDM), School of Dentistry; Department of Oral Medicine (MATM), Hospital de Clínicas de Porto Alegre (HCPA/UFRGS); Department of Pathology (LM), School of Medicine, Hospital de Clínicas de Porto Alegre (HCPA/UFRGS), Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; and Laboratory of Epithelial Biology (CSD, MATM, LOA, CHS, MDM, RMC), Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA.

ABSTRACT
Epigenetics refers to changes in cell characteristics that occur independently of modifications to the deoxyribonucleic acid (DNA) sequence. Alterations mediated by epigenetic mechanisms are important factors in cancer progression. Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive. We examined alterations in chromatin acetylation in oral lichen planus (OLP) with distinct clinical behavior and compared the alterations to the levels of DNA double-strand breaks (DSBs). We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci. Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy. Similar to H3K9ac, patients who responded poorly to therapy had increased accumulation of DNA DSB, indicating genomic instability. These findings suggest that histone modifications occur in OLP, and H3K9ac and γH2AX histones may serve as epigenetic markers for OLP recurrence.

Show MeSH
Related in: MedlinePlus