Wei-Ting Liao

Aberrant Cell Proliferation by Enhanced Mitochondrial Biogenesis via mtTFA in Arsenical Skin Cancers

Arsenic-induced Bowens disease (As-BD), a cutaneous carcinoma in situ, is thought to arise from gene mutation and uncontrolled proliferation. However, how mitochondria regulate the arsenic-induced cell proliferation remains unclear. The aim of this study was to clarify whether arsenic interfered with mitochondrial biogenesis and function, leading to aberrant cell proliferation in As-BD. Skin biopsy samples from patients with As-BD and controls were stained for cytochrome c oxidase (Complex IV), measured for mitochondrial DNA (mtDNA) copy number and the expression levels of mitochondrial biogenesis-related genes, including peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF-1), and mitochondrial transcription factor A (mtTFA). The results showed that expression of cytochrome c oxidase, mtTFA, NRF-1, and PGC-1α was increased in As-BD compared with in healthy subjects. Treatment of primary keratinocytes with arsenic at concentrations lower than 1.0 μmol/L induced cell proliferation, along with enhanced mitochondrial biogenesis. Furthermore, we observed that the mitochondrial oxygen consumption rate and intracellular ATP level were increased in arsenic-treated keratinocytes. Blocking of mitochondrial function by oligomycin A (Complex V inhibitor) or knockdown of mtTFA by RNA interference abrogated arsenic-induced cell proliferation without affecting cyclin D1 expression. We concluded that mtTFA up-regulation, augmented mitochondrial biogenesis, and enhanced mitochondrial functions may contribute to arsenic-induced cell proliferation. Targeting mitochondrial biogenesis may help treat arsenical cancers at the stage of cell proliferation.

Differential effects of arsenic on cutaneous and systemic immunity: focusing on CD4+ cell apoptosis in patients with arsenic-induced Bowen's disease

Bowens disease (BD), a carcinoma in situ of the skin, has been identified as an early lesion in arsenic carcinogenesis. Patients with arsenic-induced Bowens disease (As-BD) showed both cutaneous and systemic immune dysfunctions. We set out to evaluate the interactions between keratinocytes and lymphocytes in the context of As-BD carcinogenesis. Our results showed that As-BD lesions demonstrated a significant dermal CD4+ cell, an essential regulator of proper tumor immunity, undergoing apoptosis. In addition, it was found that the As-BD patients have lower percentage of peripheral CD4+ cells as compared with control subjects. However, the CD4+ cells from As-BD patients were less susceptible to arsenic-induced apoptosis, due to reduced tumor necrosis factor receptor 1 expression. Interestingly, arsenic was found to induce Fas expression on CD4+ cells and increase the soluble Fas ligand (sFasL) production from keratinocytes. This sFasL-containing keratinocyte supernatant was able to induce comparable CD4+ cell apoptosis for both patients and controls. Using immunofluorescent staining, increased FasL was observed in keratinocytes of As-BD lesions and Fas was expressed among infiltrating CD4+ cells. Our findings suggested that systemically, the percentage of CD4+ cells was decreased in the peripheral blood of As-BD patients. These residual CD4+ cells were less susceptible to arsenic-induced apoptosis. However, once infiltrated into the As-BD lesions, the selective CD4+ cell apoptosis might be mediated by FasL from keratinocytes. This additional tumor-anti-immune phenomenon present in the cutaneous environment provides a reasonable explanation for frequent occurrence of arsenic cancers in the skin.

Mechanistic correlations between two itch biomarkers, cytokine interleukin-31 and neuropeptide β-endorphin, via STAT3/calcium axis in atopic dermatitis.

Summary Background  Itch is the cardinal symptom of atopic dermatitis (AD). β‐Endorphin, a neuropeptide, is increased in both AD skin and sera. Interleukin (IL)‐31, an itch‐relevant cytokine, activates IL‐31 receptors in keratinocytes. However, how IL‐31 and β‐endorphin interact in AD skin remains elusive.

Enhanced MCP‐1 release by keloid CD14+ cells augments fibroblast proliferation: role of MCP‐1 and Akt pathway in keloids

Please cite this paper as: Enhanced MCP‐1 release by keloid CD14+ cells augments fibroblast proliferation: role of MCP‐1 and Akt pathway in keloids. Experimental Dermatology 2010; 19: e142–e150.

Arsenite promotes centrosome abnormalities under a p53 compromised status induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

Epidemiological evidence indicated that residents, especially cigarette smokers, in arseniasis areas had significantly higher lung cancer risk than those living in non-arseniasis areas. Thus an interaction between arsenite and cigarette smoking in lung carcinogenesis was suspected. In the present study, we investigated the interactions of a tobacco-specific carcinogen 4- (methylnitrosamino)-1-(3-pyridyl)-1-butanone (nicotine-derived nitrosamine ketone, NNK) and arsenite on lung cell transformation. BEAS-2B, an immortalized human lung epithelial cell line, was selected to test the centrosomal abnormalities and colony formation by NNK and arsenite. We found that NNK, alone, could enhance BEAS-2B cell growth at 1-5 microM. Under NNK exposure, arsenite was able to increase centrosomal abnormality as compared with NNK or arsenite treatment alone. NNK treatment could also reduce arsenite-induced G2/M cell cycle arrest and apoptosis, these cellular effects were found to be correlated with p53 dysfunction. Increased anchorage-independent growth (colony formation) of BEAS-2B cells cotreated with NNK and arsenite was also observed in soft agar. Our present investigation demonstrated that NNK could provide a p53 compromised status. Arsenite would act specifically on this p53 compromised status to induce centrosomal abnormality and colony formation. These findings provided strong evidence on the carcinogenic promotional role of arsenite under tobacco-specific carcinogen co-exposure.

Defective β1‐integrins expression in arsenical keratosis and arsenic‐treated cultured human keratinocytes

Background:  β1‐integrins, which localize to the basolateral surface of basal keratinocytes, are important in the differentiation control and proliferation of the epidermis. Many cutaneous diseases with perturbed differentiation, including arsenical keratosis, show altered patterns of integrin distribution and expression. Arsenic may induce arsenical keratosis through the differentiation and apoptosis aberration by integrins. The purpose of this study is to investigate the role of integrin and arsenic in the pathogenesis of arsenical keratosis.

Aberrant immune responses in arsenical skin cancers

Arsenic is a well‐known human carcinogen. It also impairs immune functions and activation in many aspects. However, only a small portion of arsenic‐exposed population develops skin abnormalities, including Bowens disease and skin cancers. Differential immune activation among the individuals might account for the different susceptibilities. In patients with arsenic‐induced Bowens disease, there is a selective CD4 T‐cell apoptosis through tumor necrosis factor‐alpha pathway, decrease in macrophage differentiation and phagocytosis, reduced Langerhans cell numbers and dendrites, altered regulatory T‐cell distribution, and other immune alterations. Several lines of evidence from mouse and fish studies also confirmed the potent and multifaceted effects of arsenic in the immune system. The molecular bases of immunosuppression by arsenic in lymphocytes may include chromosomal and DNA abnormalities, decreased T‐cell receptor activation, and the cellular status of oxidation and methylation. This article also reviews the causative and differential role of selective CD4 cell apoptosis and the carcinogenesis of arsenic‐induced Bowens disease.

Concentration-dependent cellular responses of arsenic in keratinocytes.

Arsenic (As) is considered as a human carcinogen or tumor‐promoting agent. Epidemiological evidences indicated that cancer incidences of residents in arseniasis areas were significantly higher in multiple organs, including urinary bladder, lungs, and especially the skin, than those living in non‐arseniasis areas. In the context of skin cancers, keratinocytes are believed to be the main target cells in As carcinogenesis. Therefore, we discuss the significance of keratinocyte‐specific effects of As on skin carcinogenesis. As is known to be cytotoxic because of its chemical reactions with the thiol group of proteins and its ability to generate free radicals during cellular metabolism. However, at relatively low concentrations, As shows stimulatory effects, such as cell activation and proliferation. Because long‐term As exposure is associated with skin carcinogenesis, we reviewed the mechanisms of As‐induced keratinocyte dysfunctions by means of time‐ and concentration‐dependent cellular responses. The mechanisms and interactions underlying As‐induced keratinocyte dysfunctions not only provide a model of As in skin carcinogenesis process but also help in understanding the regulation of As carcinogenesis in other internal organs.

Pyrrolo[2,1-c][1,4]benzodiazepine and indole conjugate (IN6CPBD) has better efficacy and superior safety than the mother compound DC-81 in suppressing the growth of established melanoma in vivo.

Melanoma is one of the most chemo-resistant cancers. The remission rate of current therapy remains low. Pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a group of antitumor antibiotics that binds to N2 of guanine to form a DNA adduct. However, significant cardiotoxicity hampers their clinical use. We have previously synthesized a PBD indole conjugate (IN6CPBD) that induced apoptosis in several cancer cell lines. The purpose of this study was to assess the efficacy and safety of the IN6CPBD for established murine melanoma cells in vivo. IN6CPBD induced more apoptosis than DC-81 as evidenced by sub-G1 distribution, annexin V positivity, and decrease mitochondrial membrane potential (DeltaPsi(mt)). The melanomas were established in C57BL/6 mice by injecting B16F10 cells via the tail vein. Three courses of therapy were instituted after day 5 and the mice were sacrificed at day 20. The tumor growth rate in the foot pad was significantly reduced in IN6CPBD-treated mice than that in DC-81- and PBS-treated mice. The tumor burden in the lungs was also reduced significantly in IN6CPBD-treated mice accompanied with the most prominent TUNEL staining. Renal function, and cardiac enzymes were not altered significantly by IN6CPBD or DC-81, however, robust deterioration of liver function was noticed in the DC-81-treated mice. In summary, potent apoptosis could be elicited by the PBD indole conjugate IN6CPBD, accompanied with a better efficacy and less liver function impairment than the mother compound DC-81 in treating established melanoma metastasis in vivo.

Differential immunological effects of infrared irradiation and its associated heat in vivo

Infrared irradiation (IR) is the most abundant fraction of sunlight reaching the earths surface and provides heat. The fever response of an animal is known to regulate its immune responses. However, the non-thermal immune responses of IR were difficult to assess owing to its close association with heat. We hypothesized that IR irradiation induced differential immunological responses, independent of its associated heat. With an IR machine coupled with a delicate temperature control system, we investigated the non-thermal immunological effects of IR in vivo. With heating at 37 °C or 39 °C using an electric blanket or IR irradiation, we measured the skins physiological parameters, including transepidermal water loss (TEWL), pH, skin hydration, elasticity, sebum production, and skin blood flow. We also measured the number of Langerhans cells in epidermal sheets and draining lymph nodes. Lymph node cells were activated by anti-CD3 antibody and their production of interleukin (IL)-5, 10, 13, 17, and interferon (IFN)-γ was measured by enzyme-linked immunosorbent assay (ELISA). The result showed that compared to heating alone, IR causes an enhanced activation of epidermal Langerhans cells, both in epidermal sheets and in draining lymph nodes. The activation of draining lymph node cells by anti-CD3 antibody in vitro induces both Th2 and Th1, but not Treg immune responses. Interestingly, IL-13, a Th2 cytokine, is induced the most. In contrast, physiological parameters and barrier functions of skin were not altered after IR irradiation. The study showed that IR alone without heat modulates immune responses in vivo, indicating that IR irradiation might regulate host immunity in a heat-independent manner.