Epigenetic regulations in alternative telomere lengthening: Understanding the mechanistic insight in arsenic-induced skin cancer patients.
- 作者列表："Bhattacharjee P","Das A","Giri AK","Bhattacharjee P
:Telomere integrity is considered to be one of the primary mechanisms during malignant transformation. Arsenic, a group 1 carcinogenic metalloid, has been reported to cause telomere lengthening in a telomerase-independent manner. Recent studies suggest a significant role for epigenetic modifications in regulating telomeric length and integrity. Here, we have explored the role of epigenetic deregulation in alternative lengthening of telomeres (ALT) in arsenic-exposed skin cancer tissues and corresponding non-tumor tissues. The relative telomere length (RTL) was analyzed by qRT-PCR using 2-ΔΔCt method. The subtelomeric methylation pattern of the four chromosomes (7q, 18p, 21q and XpYp) were analysed by Methylation Specific PCR (MSP) in 40 pairs of arsenic exposed skin cancer tissues and its corresponding control. The role of constitutive heterochromatin histone marks in the regulation of telomere length (TL) was analyzed by targeted ELISA. A 2-fold increase of relative telomere length in 85% of the arsenic-induced skin cancer tissues was observed. Among the four chromosomes, subtelomere of XpYp was found to be hypermethylated (p < 0.001) whereas 18p was hypomethylated (p < 0.01). Additionally, the level of H4K20me3, a heterochromatic mark was found to be significantly down-regulated (p < 0.0003), and inversely correlated with telomere length indicating loss of heterochromatinization of telomeric DNA. These observations highlight the novel role of epigenetic regulation in the maintenance of constitutive heterochromatin structure at telomere. Alteration in subtelomeric DNA methylation patterns and depletion of H4K20me3 might lead to loss of heterochromatinization resulting in arsenic-induced telomeric elongation. We provide novel data indicating possible alternative determinants of telomere elongation through epigenetic modifications during arsenic-induced skin carcinogenesis which could be used as early 'epimarkers' in the near future. The findings provide new insights about the mechanism of arsenic-induced carcinogenesis.
: 端粒完整性被认为是恶性转化过程中的主要机制之一。砷，一组 1 致癌类金属，已被报道以非端粒酶依赖性方式引起端粒延长。最近的研究表明表观遗传修饰在调节端粒长度和完整性方面具有重要作用。在此，我们探讨了表观遗传失调在砷暴露皮肤癌组织和相应非肿瘤组织端粒 (ALT) 替代延长中的作用。使用 2 Δ Δ ct法通过qRT-PCR分析相对端粒长度 (RTL)。通过甲基化特异性PCR (MSP) 分析 4 条染色体 (7q、 18p、 21q和XpYp) 的亚端粒甲基化模式 40 对砷暴露皮肤癌组织及其相应对照。通过靶向ELISA分析组成性异染色质组蛋白标记在端粒长度 (TL) 调控中的作用。在 85% 的砷诱导的皮肤癌组织中观察到相对端粒长度增加 2 倍。在 4 条染色体中，XpYp的亚端粒被发现是高甲基化的 (p <0.001)，而 18p是低甲基化的 (p <0.01)。此外，发现异色标记H4K20me3 的水平显著下调 (p <0.0003)，并与端粒长度呈负相关，表明端粒DNA的异色化丢失。这些观察结果强调了表观遗传调控在维持端粒组成性异染色质结构中的新作用。亚端粒DNA甲基化模式的改变和H4K20me3 的耗竭可能导致异色化的丧失，导致砷诱导的端粒延长。我们提供了新的数据，表明在砷诱导的皮肤癌变过程中，通过表观遗传修饰可能导致端粒延长的替代决定因素，这可能在不久的将来被用作早期的 “epimark”。这些发现为砷致癌机制提供了新的见解。
METHODS::Blue rubber bleb naevus syndrome (BRBNS) is an extremely rare venous malformation that often manifests as multiple haemangioma-like lesions in the skin and gastrointestinal tract. The drug sirolimus plays a key role in the signalling pathway of angiogenesis and subsequent development of BRBNS and its use has been described in several case reports. We present a case series of four patients with BRBNS who exhibited good treatment response to sirolimus. All four patients were administered oral sirolimus at doses of 1.0-1.5 mg/m2 /day with a target drug level of 5-10 ng/mL and median treatment duration of 20 months. All patients had a reduction in the size of the lesions and a normalization of coagulopathy with tolerable drug adverse reactions at follow-up. Sirolimus may be effective and safe in paediatric patients with BRBNS. Further prospective studies are suggested to evaluate the long-term effectiveness of this drug.
METHODS:BACKGROUND:Human papillomavirus (HPV) infections are associated with common dermatologic and nondermatologic diseases. Although HPV vaccines are well established as preventive measures for genital warts and cervical neoplasia, their use as therapeutic agents deserves greater attention. OBJECTIVE:To evaluate the use of HPV vaccine(s) as a treatment modality for cutaneous and/or mucosal disease. METHODS:A primary literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in January 2019 by using the PubMed and Cochrane databases. RESULTS:A total of 63 articles with 4439 patients were included. The majority of patients with cutaneous warts, recurrent respiratory papillomatosis, and squamous and basal cell carcinomas were successfully treated with HPV vaccination. Preliminary data on patients with pre-existing anogenital warts, cervical intraepithelial neoplasia, anal intraepithelial neoplasia, and vulvar intraepithelial neoplasia is promising. LIMITATIONS:This review was limited by the lack of controls, patients' previous HPV vaccination status, and publication bias. CONCLUSION:The commercially available three-dose, quadrivalent HPV vaccine is a potential therapeutic option for the treatment of cutaneous warts, recurrent respiratory papillomatosis, and squamous and basal cell carcinomas. Noncommercially available HPV vaccines demonstrate therapeutic response for treating anogenital warts, cervical intraepithelial neoplasia, anal intraepithelial neoplasia, and vulvar intraepithelial neoplasia. The vaccine's efficacy as an adjunct therapy for HPV-associated cutaneous and/or mucosal disease warrants further exploration.
METHODS::Our understanding of melanoma precursors and progression to melanoma has developed as a result of advances in the field of molecular diagnostics. We now better understand the potential for genetic heterogeneity within a single lesion. Combined tumors can pose a diagnostic challenge when deciding the line between benign and malignant, which in turn has direct implications for patient management. Primary cilia (PC) are ubiquitous sensory organelles that have essential functions in cellular proliferation, differentiation, and development. The ciliation index (percentage of ciliated melanocytes) has been shown to reliably differentiate melanoma, which fail to ciliate, from melanocytic nevi, which retain PC. We therefore analyzed the potential for using the ciliation index to differentiate benign and malignant components in combined melanocytic lesions. We collected patient samples (n = 10) of unequivocal combined lesions with both melanoma and associated nevus components. Melanocytes were highlighted with SOX10 and costained with gamma-Tubulin and acetylated alpha-Tubulin to highlight the basal body and cilium, respectively. The number of melanocytes retaining cilia under high-power microscopy was examined. The melanoma component had average of 4% ciliation (SD: 7%), whereas the associated nevus component was significantly higher with 59% ciliation (SD: 17%). These data show that PC may be a reliable means of distinguishing benign from malignant components within a single tumor. The ciliation index may be a helpful tool in distinguishing challenging cases of combined lesions of melanoma in situ with a dermal nevus component from invasive melanoma, thus promoting improved staging and clinical management.