Mahmoud R. Hussein

Ultraviolet radiation and skin cancer: molecular mechanisms

Abstract:  Every living organism on the surface of the earth is exposed to the ultraviolet (UV) fraction of the sunlight. This electromagnetic energy has both life‐giving and life‐endangering effects. UV radiation can damage DNA and thus mutagenize several genes involved in the development of the skin cancer. The presence of typical signature of UV‐induced mutations on these genes indicates that the ultraviolet‐B part of sunlight is responsible for the evolution of cutaneous carcinogenesis. During this process, variable alterations of the oncogenic, tumor‐suppressive, and cell‐cycle control signaling pathways occur. These pathways include (a) mutated PTCH (in the mitogenic Sonic Hedgehog pathway) and mutated p53 tumor‐suppressor gene in basal cell carcinomas, (b) an activated mitogenic ras pathway and mutated p53 in squamous cell carcinomas, and (c) an activated ras pathway, inactive p16, and p53 tumor suppressors in melanomas. This review presents background information about the skin optics, UV radiation, and molecular events involved in photocarcinogenesis.

Apoptosis and melanoma: molecular mechanisms

Melanoma cells can undergo self‐destruction via programmed cell death, i.e. apoptosis. In these tumours, the molecular components of apoptosis include positive (apoptotic) and negative (anti‐apoptotic) regulators. The former include p53, Bid, Noxa, PUMA, Bax, TNF, TRAIL, Fas/FasL, PITSLRE, interferons, and c‐KIT/SCF. The latter include Bcl‐2, Bcl‐XL, Mcl‐1, NF‐KB, survivin, livin, and ML‐IAP. Alternatively, some molecules such as TRAF‐2, c‐Myc, endothelins, and integrins may have either pro‐ or anti‐apoptotic effects. Some of these molecules are of potential therapeutic use, such as: (1) p53, which influences resistance to chemotherapy; (2) Mcl‐1 and Bcl‐XL, which can override apoptosis; (3) TRAIL, which has selective fatal effects on tumour cells; (4) NF‐KB, which when downregulated sensitizes cells to TRAIL and TNF; (5) the PITSLRE kinases, whose alteration appears to result in Fas resistance; (6) interferons, which sensitize cells to other factors; and (7) survivin and other IAPs that inhibit apoptosis. This review summarizes the state of current knowledge about the key molecular components and mechanisms of apoptosis in melanoma, discusses potential therapeutic ramifications, and provides directions for future research. Copyright

Restoration of ovarian function after autotransplantation of intact frozen-thawed sheep ovaries with microvascular anastomosis

OBJECTIVE To test the feasibility of transplanting an intact frozen-thawed ovary with microvascular anastomosis of the ovarian vascular pedicle to the deep inferior epigastric vessels. DESIGN Chronic survival study. SETTING Biological Resources Unit, The Cleveland Clinic Foundation. ANIMAL(S) Adult merino ewes. INTERVENTION(S) Bilateral laparoscopic oophorectomy was performed on 17 synchronized ewes. In one group of animals (Group I, n = 11), both ovaries were cryopreserved intact with their vascular pedicles. In another group of animals (Group II, n = 6), ovarian cortical strips were prepared from each ovary and cryopreserved. After thawing, follicular viability and apoptosis rates were assessed using one ovary. The other ovary was transplanted to the abdominal wall with microvascular anastomosis (Group I). In Group II, the ovarian cortical strips were placed in the anterior abdominal wall. Ovaries were harvested after 8-10 days in situ and subjected to histological evaluation. MAIN OUTCOME MEASURE(S) Blood flow, apoptotic signals, follicular viability, serum estradiol (E(2)), follicle-stimulating hormone (FSH), and histology. RESULT(S) No significant differences were found in the mean values of apoptosis (mostly in the atretic and some secondary follicles) and follicular viability in both groups. In Group I, immediate and long-term patency were documented in 100% and 27% (3/11) of the grafts, respectively; and postoperative FSH levels were similar to preoperative values in animals with patent vessels. In Group II, postoperative FSH levels were significantly higher than the preoperative ones (P=.03). CONCLUSION(S) Transplantation of an intact frozen-thawed ovary is technically feasible. Using this approach, immediate restoration of vascular supply and ovarian hormonal functions is possible.

Mucocutaneous Splendore-Hoeppli phenomenon.

Splendore‐Hoeppli phenomenon (asteroid bodies) is the in vivo formation of intensely eosinophilic material (radiate, star‐like, asteroid or club‐shaped configurations) around microorganisms (fungi, bacteria and parasites) or biologically inert substances. This study presents a literature review concerning Splendore‐Hoeppli reaction in the mucocutaneous diseases. It examines the histopathological features, nature and differential diagnosis of this reaction. It also discusses the mucocutaneous infections and the non‐infective diseases associated with it. Available studies indicate that several mucocutaneous infections can generate Splendore‐Hoeppli reaction. The fungal infections include sporotrichosis, pityrosporum folliculitis, zygomycosis, candidiasis, aspergillosis and blastomycosis. The bacterial infections include botryomycosis, nocardiosis and actinomycosis. The parasitic conditions include orbital pythiosis, strongyloidiasis, schistosomiasis and cutaneous larva migrans. In addition, Splendore‐Hoeppli reaction may be seen with non‐infective pathology such as hypereosinophilic syndrome and allergic conjunctival granulomas. The Splendore‐Hoeppli reaction material comprises antigen‐antibody complex, tissue debris and fibrin. Although the exact nature of this reaction is unknown, it is thought to be a localized immunological response to an antigen‐antibody precipitate related to fungi, parasites, bacteria or inert materials. The characteristic formation of the peribacterial or perifungal Splendore‐Hoeppli reaction probably prevents phagocytosis and intracellular killing of the insulting agent leading to chronicity of infection. To conclude, Splendore‐Hoeppli reaction is a tell tale of a spectrum of infections and reactive conditions. The molecular pathways involved in the development of this reaction are open for future investigations.

Intake of melatonin is associated with amelioration of physiological changes, both metabolic and morphological pathologies associated with obesity: an animal model

Obesity and its associated metabolic pathologies are the most common and detrimental diseases, affecting over 50% of the adult population. Our knowledge about the protective effects of melatonin against high‐fat diet (HFD)‐induced obesity is still marginal. In this investigation, we hypothesized that melatonin can minimize the metabolic pathologies and morphological changes associated with obesity in animals receiving an HFD. To examine these effects, and to test our hypothesis, an animal model formed of male Boscat white rabbits was established. The animals were divided into three groups: (i) a control group fed regular diet; (ii) an obesity group fed an HFD for 12 weeks; and (iii) a treated group fed HFD for 12 weeks and then treated with melatonin for 4 weeks. The animals were killed and their serum and tissues were evaluated for: (i) lipid profile (cholesterol, triglycerides and low‐density lipoprotein) and glucose; (ii) antioxidant enzyme (serum glutathione peroxidase, GSH‐PX); and (iii) fatty changes (liver, kidney and blood vessels). Compared with the control group, intake of HFD (obesity group) was associated with: (i) a statistically significant increase in blood pressure, heart rate, sympathetic nerve activity, body weight, food consumption, serum lipids, blood glucose levels and atherogenic index; (ii) decreased level of GSH‐PX and high‐density lipoprotein (HDL); and (iii) fatty changes in the liver and kidney as well as atheromatous changes in the blood vessels. Compared with the obesity group, intake of melatonin (treated group) was associated with: (i) a statistically significant decrease in blood pressure, heart rate, sympathetic nerve activity, body weight, food consumption, serum lipids, blood glucose levels and atherogenic index; (ii) increased level of GSH‐PX and HDL; and (iii) disappearance of fatty changes in the liver and kidney as well as atheromatous changes in the blood vessels. The administration of melatonin reduced the metabolic pathologies associated with the intake of HFD, suggesting a protective role. Although the underlying mechanisms are unclear, they may include its antioxidant and receptor‐mediated effects. The clinical ramifications of these effects await further investigations.

Comprehensive analysis of 112 melanocytic skin lesions demonstrates microsatellite instability in melanomas and dysplastic nevi, but not in benign nevi

Introduction: Alterations in the length of DNA repetitive sequences (microsatellite instability (MSI)) represent distinct tumorigenic pathways associated with several familial and sporadic tumors.

Genetic pathways to melanoma tumorigenesis

The incidence of cutaneous malignant melanomas is growing faster than that of any other cancer and therefore posing a major heath threat worldwide. In melanocytic skin tumours, the feasibility of correlating a specific pathological stage with a corresponding genetic alteration provides a remarkable opportunity to study the multistep tumorigenesis model. This multistep melanoma tumorigenesis is best described as a continuum of transformation of the melanocytes, melanocytic dysplasia, and melanoma formation. These steps involve genotypic alterations including loss of tumour suppressor genes, microsatellite instability, and alterations of the mismatch repair system. This review seeks to examine melanoma tumorigenesis based on these genetic changes.

Alterations of the CD4+, CD8+ T Cell Subsets, Interleukins-1β, IL-10, IL-17, Tumor Necrosis Factor-α and Soluble Intercellular Adhesion Molecule-1 in Rheumatoid Arthritis and Osteoarthritis: Preliminary Observations

Rheumatoid arthritis is a multisystem disease with underlying immune mechanisms. Osteoarthritis is a debilitating, progressive disease of diarthrodial joints associated with the aging process. Although much is known about the pathogenesis of rheumatoid arthritis and osteoarthritis, our understanding of some immunologic changes remains incomplete. This study tries to examine the numeric changes in the T cell subsets and the alterations in the levels of some cytokines and adhesion molecules in these lesions. To accomplish this goal, peripheral blood and synovial fluid samples were obtained from 24 patients with rheumatoid arthritis, 15 patients with osteoarthritis and six healthy controls. The counts of CD4 + and CD8 + T lymphocytes were examined using flow cytometry. The levels of some cytokines (TNF-α, IL1-β, IL-10, and IL-17) and a soluble intercellular adhesion molecule-1 (sICAM-1) were measured in the sera and synovial fluids using enzyme linked immunosorbant assay. We found some variations in the counts of T cell subsets, the levels of cytokines and sICAM-1 adhesion molecule between the healthy controls and the patients with arthritis. High levels of IL-1β, IL-10, IL-17 and TNF-α (in the serum and synovial fluid) were observed in arthritis compared to the healthy controls. In rheumatoid arthritis, a high serum level of sICAM-1 was found compared to its level in the synovial fluid. A high CD4+/CD8+ T cell ratio was found in the blood of the patients with rheumatoid arthritis. In rheumatoid arthritis, the cytokine levels correlated positively with some clinicopathologic features. To conclude, the development of rheumatoid arthritis and osteoarthritis is associated with alteration of the levels of some cytokines. The assessment of these immunologic changes may have potential prognostic roles.

Alterations of mismatch repair protein expression in benign melanocytic nevi, melanocytic dysplastic nevi, and cutaneous malignant melanomas.

Immunoperoxidase-staining methods were used to examine the expression of hMLH1, hMSH2, and hMSH6 mismatch repair (MMR) proteins in 50 melanocytic lesions. Microsatellite instability (MSI), screened previously in these lesions by polymerase chain reaction–based microsatellite assay, showed low-level microsatellite instability (MSI-L) in 11 of 22 melanocytic dysplastic nevi (MDN) and two of nine primary cutaneous malignant melanomas (CMMs) but not in the benign melanocytic nevi (BN). Mismatch repair proteins were widely expressed in the epidermis and adnexal structures. All lesions showed positive immunoreactivity with a gradual decrease in the MMR staining values during the progression from BN to MDN to CMMs. The average percentage of positively (PP) stained cells for hMLH1, hMSH2, and hMSH6 in BN was 85.50 ± 1.95, 77.90 ± 4.50, and 87.11 ± 1.85, respectively. The PP cell values in CMMs were significantly reduced as compared with BN (75.22 ± 3.57, p = 0.01; 56.11 ± 8.73, p = 0.02; 65.22 ± 6.47, p = 0.0002 for hMLH1, hMSH2, and hMSH6, respectively). No comparable significant difference was found between microsatellite stable and MSI-L lesions (p = 0.173, p = 0.458, and p = 0.385), suggesting a lack of correlation between MMR expression and MMR function. There was a direct correlation between PP cell values of hMSH2 and hMSH6 (R = 0.39, p = 0.008), implying that their expression could be regulated by a common mechanism. Thus, an important finding of these studies was the reduction of MMR protein levels in CMMs; whether this reflects underlying genetic or epigenetic mechanisms is still to be determined.

Analysis of the mononuclear inflammatory cell infiltrate in the normal breast, benign proliferative breast disease, in situ and infiltrating ductal breast carcinomas: preliminary observations

Background: Mammary carcinogenesis is a multistep process entailing the transition from normal breast to benign proliferative breast disease (ductal hyperplasia) to ductal carcinoma in situ to infiltrating ductal carcinoma. Hypothesis: These transitions are associated with changes in the mononuclear inflammatory cell infiltrate. Materials and methods: A total of 53 mastectomy specimens of normal breast, benign proliferative breast disease, ductal carcinoma in situ and infiltrating ductal carcinoma were evaluated for mononuclear inflammatory cell infiltrate by using immunohistological methods and monoclonal antibodies including CD20, CD68, CD3 and granzyme B, histiocytes, T cells and cytotoxic T cells. Results: Transitions from normal breast to the subsequent tissue with lesions (normal skin v benign proliferative breast disease v ductal carcinoma in situ v infiltrating ductal carcinoma) were associated with significantly (p<0.01) increased mean (SD) density of mononuclear inflammatory cell infiltrate at the parenchyma (3.2 (1.0) v 26.4 (7.8) v 33.6 (7.9) v 39.1 (4.7) for CD20+ B cells; 2.8 (1.0) v 81.5 (14.0) v 84.0 (14.9) v103.7 (3.9) for CD3; 1.3 (2.0) v 3.8 (4.0) v 12.7 (23) v 22.1 (25.0) for CD68+ macrophages; 2.0 (1.0) v 58.3 (5.0) v 60.0 (10.0) v 74.1 (28.0) for granzyme B+ cytotoxic T cells) and at the stroma (0.7 (1.0) v 3.0 (5.0) v 13.3 (20) v 16.7 (30.0) for CD20+ B cells; 1.0 (2.06) v 4.0 (2.5) v 16.7 (5.0) v 21.7 (15) for CD68+ macrophages; 1.4 (0.6) v 4.2 (1.2) v 46.6 (16.7) v 77.0 (5.0) for CD3+ cells and 0 (0) v 0.5 (1.0) v 0.7 (1.0) v 0.7 (1.0) for granzyme B+ cytotoxic T cells). Conclusions: The increased mononuclear inflammatory cell infiltrate during mammary carcinogenesis may reflect non-specific or specific immunological processes.