Steffen Emmert

Antiproliferative activity of ecteinascidin 743 is dependent upon transcription-coupled nucleotide-excision repair

While investigating the novel anticancer drug ecteinascidin 743 (Et743), a natural marine product isolated from the Caribbean sea squirt, we discovered a new cell-killing mechanism mediated by DNA nucleotide excision repair (NER). A cancer cell line selected for resistance to Et743 had chromosome alterations in a region that included the gene implicated in the hereditary disease xeroderma pigmentosum (XPG, also known as Ercc5). Complementation with wild-type XPG restored the drug sensitivity. Xeroderma pigmentosum cells deficient in the NER genes XPG, XPA, XPD or XPF were resistant to Et743, and sensitivity was restored by complementation with wild-type genes. Moreover, studies of cells deficient in XPC or in the genes implicated in Cockayne syndrome (CSA and CSB) indicated that the drug sensitivity is specifically dependent on the transcription-coupled pathway of NER. We found that Et743 interacts with the transcription-coupled NER machinery to induce lethal DNA strand breaks.

Cancer and neurologic degeneration in xeroderma pigmentosum: long term follow-up characterises the role of DNA repair

Background The frequency of cancer, neurologic degeneration and mortality in xeroderma pigmentosum (XP) patients with defective DNA repair was determined in a four decade natural history study. Methods All 106 XP patients admitted to the National Institutes of Health from 1971 to 2009 were evaluated from clinical records and follow-up. Results In the 65 per cent (n=69) of patients with skin cancer, non-melanoma skin cancer (NMSC) was increased 10 000-fold and melanoma was increased 2000-fold in patients under age 20. The 9 year median age at diagnosis of first non-melanoma skin cancer (NMSC) (n=64) was significantly younger than the 22 year median age at diagnosis of first melanoma (n=38)—a relative age reversal from the general population suggesting different mechanisms of carcinogenesis between NMSC and melanoma. XP patients with pronounced burning on minimal sun exposure (n=65) were less likely to develop skin cancer than those who did not. This may be related to the extreme sun protection they receive from an earlier age, decreasing their total ultraviolet exposure. Progressive neurologic degeneration was present in 24% (n=25) with 16/25 in complementation group XP-D. The most common causes of death were skin cancer (34%, n=10), neurologic degeneration (31%, n=9), and internal cancer (17%, n=5). The median age at death (29 years) in XP patients with neurodegeneration was significantly younger than those XP patients without neurodegeneration (37 years) (p=0.02). Conclusion This 39 year follow-up study of XP patients indicates a major role of DNA repair genes in the aetiology of skin cancer and neurologic degeneration.

Alleviation of chronic venous leg ulcers with a hand-held dielectric barrier discharge plasma generator (PlasmaDerm® VU-2010): results of a monocentric, two-armed, open, prospective, randomized and controlled trial (NCT01415622)

Cold atmospheric plasma (CAP, i.e. ionized air) is an innovating promising tool in reducing bacteria.

Postoperative morbidity of lymph node excision for cutaneous melanoma-sentinel lymphonodectomy versus complete regional lymph node dissection.

For patients with melanoma metastasis to a sentinel lymph node, subsequent complete regional lymph node dissection (CLND) is currently regarded to be the surgical standard. This approach, however, has not been confirmed by controlled studies, so that surgical morbidity is of primary importance. Using clinical examination and a questionnaire, we determined morbidity in 315 patients with axillary or inguinal lymph node excision on whom 275 sentinel lymphonodectomies (SLNEs) and 90 CLNDs were performed. The overall incidence of at least one complication following SLNE was 13.8%. The short-term complication rate was 11.3% (allergic reaction to blue dye 0%, wound breakdown 0%, haematoma 2.5%, wound infection 3.6%, seroma 6.9%). The incidence of long-term complications was 4.1% (persistent tattoo 0.4%, functional deficit 0.4%, nerve dysfunction/pain 0.7% or swelling 2.5%). All complications were mild. Significantly, the complication rate was not higher for patients aged 70 years or older. After CLND, the overall complication rate was significantly higher (65.5%, P<0.000001). The incidence of short-term complications was 50% (haematoma 0%, wound breakdown 6.7%, wound infection 24.7% or seroma 34.8%). The incidence of long-term complications was also 50% (nerve dysfunction/pain 8.9%, functional deficit 16.8%, swelling 37.1%). Overall, inguinal lymph node excision was burdened by a higher complication rate (P=0.015). Age and sex did not influence postoperative morbidity. No deaths linked to either procedure were noted. Complication rates after SLNE are low and most complications are minor and short-lasting. In contrast, CLND has been demonstrated to be a major and potentially morbid surgical procedure. This highlights the importance of testing the therapeutic value that CLND adds to the sentinel lymph node procedure.

The acidification of lipid film surfaces by non-thermal DBD at atmospheric pressure in air

We studied the acidifying efficiency of a cold atmospheric pressure plasma treatment and ambient air as a working gas on lipid films. Acidification of a thin water film could be observed on plasma-treated surfaces of wool wax, pork sebum and human lipids. This pH shift was partly attributable to NOx species and to the formation of nitric acid in the upper layers of the substrates. The acidic compounds on the lipid surfaces resulted in pH shifts for up to 2 h after plasma exposure, which might be beneficial for pH-targeted therapies in dermatology.

Xeroderma Pigmentosum-Variant Patients from America, Europe, and Asia

Xeroderma pigmentosum-variant (XP-V) patients have sun sensitivity and increased skin cancer risk. Their cells have normal nucleotide excision repair, but have defects in the POLH gene encoding an error-prone polymerase, DNA polymerase eta (pol eta). To survey the molecular basis of XP-V worldwide, we measured pol eta protein in skin fibroblasts from putative XP-V patients (aged 8-66 years) from 10 families in North America, Turkey, Israel, Germany, and Korea. Pol eta was undetectable in cells from patients in eight families, whereas two showed faint bands. DNA sequencing identified 10 different POLH mutations. There were two splicing, one nonsense, five frameshift (3 deletion and 2 insertion), and two missense mutations. Nine of these mutations involved the catalytic domain. Although affected siblings had similar clinical features, the relation between the clinical features and the mutations was not clear. POLH mRNA levels were normal or reduced by 50% in three cell strains with undetectable levels of pol eta protein, indicating that nonsense-mediated message decay was limited. We found a wide spectrum of mutations in the POLH gene among XP-V patients in different countries, suggesting that many of these mutations arose independently.

Selection of Patients for Long-term Surveillance With Digital Dermoscopy by Assessment of Melanoma Risk Factors

OBJECTIVE To identify patients at increased melanoma risk who benefit from long-term surveillance with digital dermoscopy. DESIGN Prospective, nonrandomized, observational study. SETTING University-based surveillance program. PARTICIPANTS Six hundred eighty-eight patients prospectively categorized into defined melanoma risk groups and followed up (mean, 44.3 months) by clinical examinations, dermoscopy, and, for atypical nevi, sequential digital dermoscopy. MAIN OUTCOME MEASURE Association between patient risk factors and detection of melanomas. RESULTS Odds ratios from a multivariate logistic regression analysis indicated a highly increased melanoma risk for patients with familial atypical mole and multiple melanoma (FAMMM) syndrome, atypical mole syndrome (AMS), or previous melanoma. Each digitally documented atypical lesion (range, 1-17 lesions per patient) denoted a significant 10% increase in melanoma risk. Patients with higher melanoma risk (1) showed a higher percentage of melanomas detected by digital dermoscopy (FAMMM syndrome group, 50%; AMS group, 22%), (2) more often developed multiple melanomas within shorter intervals, and (3) showed a ratio of melanoma to benign results for lesions excised because of dynamic changes of 1:15 (AMS group) or 1:4 (FAMMM syndrome group). Melanomas detected by digital dermoscopy were significantly thinner (0.41 mm in mean Breslow thickness) compared with melanomas detected by other means (0.62 mm; P = .04). CONCLUSIONS We suggest an individualized surveillance plan, with digital dermoscopy performed at follow-up intervals of 3 months for patients with FAMMM syndrome and 6 to 12 months (depending on additional risk factors) for those with AMS. Patients with multiple common nevi and no additional risk factors had no benefit from sequential digital dermoscopy.

Lessons learned from DNA repair defective syndromes

Abstract:  Genomic instability is the driving force behind cancer development. Human syndromes with DNA repair deficiencies comprise unique opportunities to study the clinical consequences of faulty genome maintenance leading to premature aging and premature cancer development. These syndromes include chromosomal breakage syndromes with defects in DNA damage signal transduction and double‐strand break repair, mismatch repair defective syndromes as well as nucleotide excision repair defective syndromes. The same genes that are severely affected in these model diseases may harbour more subtle variations in the ‘healthy’ normal population leading to genomic instability, cancer development, and accelerated aging at later stages of life. Thus, studying those syndromes and the molecular mechanisms behind can significantly contribute to our understanding of (skin) cancerogenesis as well as to the development of novel individualized preventive and therapeutic anticancer strategies. The establishment of centers of excellence for studying rare genetic model diseases may be helpful in this direction.

Forty-two novel COL7A1 mutations and the role of a frequent single nucleotide polymorphism in the MMP1 promoter in modulation of disease severity in a large European dystrophic epidermolysis bullosa cohort.

Background  Dystrophic epidermolysis bullosa (DEB) is a severe genetic skin blistering disorder caused by mutations in the gene COL7A1, encoding collagen VII. Recently, the MMP1 promoter single nucleotide polymorphism (SNP) rs1799750, designated as 1G 2G, was shown to be involved in modulation of disease severity in patients with recessive DEB (RDEB), and was proposed as a genetic modifier.

Hybrid cell vaccination in metastatic melanoma: clinical and immunologic results of a phase I/II study.

Hybrid cell vaccination with cell fusion products (CFPs) of autologous tumor cells and mature allogenic MHC II bearing dendritic cells has been described to induce cytotoxic T lymphocyte (CTL)-mediated immune responses. The aim of this study was to assess safety, antitumor activity, and immune responses of a CFP-vaccine in patients with disseminated malignant melanoma. In a phase I/II study, we treated 11 patients by monthly intracutaneous or subcutaneous application of a CFP vaccine generated by electrofusion of autologous melanoma cells with mature allogenic dendritic cells. In addition, patients received subcutaneous low-dose interleukin-2 injections for 6 days after each vaccination. No serious adverse effects were observed. Ten patients showed progressive disease and one patient had a short-lasting stable disease. None of the patients developed a positive delayed-type hypersensitivity reaction against irradiated autologous melanoma cells. In 2 patients, who were monitored in more detail, we found no evidence of induction of a specific antimelanoma T-cell response by analyzing the proliferation, cytokine secretion, and cytotoxicity of their T cells toward autologous melanoma cells. No unequivocal beneficial effects of the used CFP vaccine could be demonstrated.