Recording 2nd order PQ:PMMA reflective VBG for diode laser output spectrum narrowing.

Two 2nd order PQ:PMMA reflecting VBGs with Bragg wavelengths of 488.8 nm and 525.6 nm were recorded using 532 nm as the recording wavelength. The formation of 2nd order PQ:PMMA VBG is explained and simulated based on the diffusion model of the PQ molecules in the PMMA matrix. The 525.6 nm VBG successfully served as the ECDL cavity mirror of a 522 nm diode laser and achieved more than 10000-fold output spectrum narrowing.

The retinoid X receptor agonist, 9-cis UAB30, inhibits cutaneous T-cell lymphoma proliferation through the SKP2-p27kip1 axis.

BACKGROUND: Bexarotene (Targretin®) is currently the only FDA approved retinoid X receptor (RXR) -selective agonist for the treatment of cutaneous T-cell lymphomas (CTCLs). The main side effects of bexarotene are hypothyroidism and elevation of serum triglycerides (TGs). The novel RXR ligand, 9-cis UAB30 (UAB30) does not elevate serum TGs or induce hypothyroidism in normal subjects. OBJECTIVES: To assess preclinical efficacy and mechanism of action of UAB30 in the treatment of CTCLs and compare its action with bexarotene. METHODS: With patient-derived CTCL cell lines, we evaluated UAB30 function in regulating growth, apoptosis, cell cycle check points, and cell cycle-related markers. RESULTS: Compared to bexarotene, UAB30 had lower half maximal inhibitory concentration (IC50) values and was more effective in inhibiting the G1 cell cycle checkpoint. Both rexinoids increased the stability of the cell cycle inhibitor, p27kip1 protein, in part, through targeting components involved in the ubiquitination-proteasome system: 1) decreasing SKP2, a F-box protein that binds and targets p27kip1 for degradation by 26S proteasome and 2) suppressing 20S proteasome activity (cell line-dependent) through downregulation of PSMA7, a component of the 20S proteolytic complex in 26S proteasome. CONCLUSIONS: UAB30 and bexarotene induce both early cell apoptosis and suppress cell proliferation. Inhibition of the G1 to S cell cycle transition by rexinoids is mediated, in part, through downregulation of SKP2 and/or 20S proteasome activity, leading to increased p27kip1 protein stability. Because UAB30 has minimal effect in elevating serum TGs and inducing hypothyroidism, it is potentially a better alternative to bexarotene for the treatment of CTCLs.

Study of temperature distributions in pc-WLEDs with different phosphor packages.

Phosphor converted white LEDs (pc-WLED) with different geometries, namely remote-dome, remote-plate, half-dome, and conformal-coating packages, were studied using simulations to obtain the thermal power and the temperature distribution. The results of an experiment carried out to measure the temperature distribution in these pc-WLEDs validate the simulation results. A hotspot always occurs in the phosphor region. The conformal-coating package is the most feasible choice to reduce the hotspot temperature comparing with the other geometries.

Osteopontin mediates tumorigenic transformation of a preneoplastic murine cell line by suppressing anoikis: an Arg-Gly-Asp-dependent-focal adhesion kinase-caspase-8 axis.

Osteopontin (OPN), an adhesive, matricellular glycoprotein, is a rate-limiting factor in tumor promotion of skin carcinogenesis. With a tumor promotion model, the JB6 Cl41.5a cell line, we have shown that suppressing 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced OPN expression markedly inhibits TPA-induced colony formation in soft agar, an assay indicative of tumorigenic transformation. Further, the addition of exogenous OPN promotes colony formation of these cells. These findings support a function of OPN in mediating TPA-induced neoplastic transformation of JB6 cells. In regard to the mechanism of action by OPN, we hypothesized that, for JB6 cells grown in soft-agar, secreted OPN induced by TPA stimulates cell proliferation and/or prevents anoikis to facilitate TPA-induced colony formation. Analyses of cell cycle and cyclin D1 expression, and direct cell counting of JB6 cells treated with OPN indicate that OPN does not stimulate cell proliferation relative to non-treated controls. Instead, at 24 h, OPN decreases anoikis by 41%, as assessed by annexin V assays. Further, in suspended cells OPN suppresses caspase-8 activation, which is mediated specifically through its RGD-cell binding motif that transduces signals through integrin receptors. Transfection studies with wild-type and mutant focal adhesion kinases (FAK) and Western blot analyses suggest that OPN suppression of caspase-8 activation is mediated through phosphorylation of FAK at Tyr(861). In summary, these studies indicate that induced OPN is a microenvironment modulator that facilitates tumorigenic transformation of JB6 cells by inhibiting anoikis through its RGD-dependent suppression of caspase-8 activity, which is mediated in part through the activation of FAK at Tyr(861).

Osteopontin facilitates ultraviolet B-induced squamous cell carcinoma development.

BACKGROUND: Osteopontin (OPN) is a matricellular glycoprotein that is markedly expressed in cutaneous squamous cell carcinomas (cSCCs) and in actinic keratoses implicating its role in photocarcinogenesis. OBJECTIVE: To determine whether OPN facilitates the development of cSCC and its function. METHODS: cSCCs development was compared between wild-type (WT) and OPN-null mice subjected to UVB irradiation for 43 weeks. UVB-induced OPN expression was determined by Western blot, immunoprecipitation, ELISA, and semi-quantitative RT-PCR. Epidermal layer and TUNEL analyses assessed if OPN mediates UVB-induced epidermal hyperplasia or suppresses UVB-induced apoptosis of basal keratinocytes, respectively. In vitro experiments determined whether OPN enhances cell survival of UVB-induced apoptosis and its potential mechanisms. Immunohistochemical analyses of epidermis assessed the expression of CD44 and focal adhesion kinase (FAK), molecules that mediate OPN survival function. RESULTS: Compared to female WT mice, OPN-null mice did not develop cSCCs. UVB irradiation stimulated OPN protein expression in the dorsal skin by 11h and remains high at 24-48h. OPN did not mediate UVB-induced epidermal hyperplasia; instead, it protected basal keratinocytes from undergoing apoptosis upon UVB exposure. Likewise, the addition of OPN suppressed UVB-induced OPN-null cSCC cell apoptosis, the activation of caspase-9 activity, and increased phosphorylation of FAK at Y397. Furthermore, the expression of CD44 and FAK in WT mice epidermis was greater than that of OPN-null mice prior to and during early acute UVB exposure. CONCLUSION: These data support the hypothesis that chronic UVB-induced OPN expression protects the survival of initiated basal keratinocytes and, consequently, facilitates cSCC develop.

Transverse modes of a laser using volume Bragg grating as the cavity mirror.

A simulation and experiment were performed to demonstrate that a laser using volume Bragg grating as one of the cavity mirrors can achieve lasing even if the laser cavity length exceeds the traditional stable cavity condition. The laser transverse mode changes from a Gaussian beam into a ring-shaped mode as the laser cavity length increases from stable to unstable cavity conditions. At the same time, the effective modal reflectivity is reduced as the cavity length increases.

Host-derived osteopontin maintains an acute inflammatory response to suppress early progression of extrinsic cancer cells.

The matricellular protein osteopontin (OPN), expressed in various cancer types and elevated in the blood of cancer patients, is thought to have different functions when derived from host versus cancer cells. To assess the effect of host-derived OPN on growth of cancers of epithelial origin, we established a line of cutaneous squamous cell carcinoma (SCC) cells, named ONSC, which lacks the OPN gene and develops SCC in syngeneic wild-type (WT) and OPN-null mice. At 8 and/or 10 week after subcutaneous injection of ONSC cells in mice, however, there was a lower tumor incidence in WT mice, suggesting that host-derived OPN is associated with suppression of early growth of extrinsic cancer cells. Histological, immunohistochemical, biochemical and hematological analyses were performed on the tumor microenvironment and blood from tumor-bearing mice during the first week after implantation. Host-derived OPN suppression of extrinsic ONSC cell progression is likely mediated through elicitation of an early innate inflammatory response, through its function as a chemoattractant and/or by enhancing survival of inflammatory cells. Further, consistent with a previous report, the serum levels of host-derived OPN, which are elevated during the early phase of tumor growth in mice implanted with ONSC, appear to reflect an anti-tumor progression effect.

Establishment and characterization of an osteopontin-null cutaneous squamous cell carcinoma cell line.

Osteopontin (OPN) is a secreted glycoprotein implicated to function in cancer development and metastasis. Although elevated expression of OPN are observed in cancer cells of various types, in some cases, only the cells in the stromal region surrounding the tumor express OPN, suggesting distinct functional roles for this protein derived from host cells and from cancer cells. To provide a model for addressing the functions and mechanisms of host-derived OPN in cancer progression and metastasis, a cutaneous squamous cell carcinoma cell line (ONSC) that lacks the OPN gene, Spp1, was established. This line of cells was derived from a squamous cell carcinoma that developed in a female, OPN-null mouse subjected to two-stage skin carcinogenesis. Morphologically, ONSC cells resemble epithelial cells, and they express the epithelial markers, K1, K14, and p63, as confirmed by immunohistochemical analyses. Genomic analyses indicate the presence of mutated H-Ras and p53 genes. ONSC cells form colonies in soft agar and, subcutaneously injected into athymic nude mice, develop into squamous cell carcinomas that metastasize to the lungs. Lacking OPN expression, these squamous cell carcinoma cells provide a model to address the function of host OPN in the context of cancer progression and metastasis.

Osteopontin expression in normal skin and non-melanoma skin tumors.

Osteopontin (OPN) is an adhesive, matricellular glycoprotein, whose expression is elevated in many types of cancer and has been shown to facilitate tumorigenesis in vivo. To understand the role of OPN in human skin cancer, this study is designed to determine whether OPN is expressed in premalignant [solar/actinic keratosis (AK)] and in malignant skin lesions such as squamous cell carcinomas (SCC) and basal cell carcinomas (BCC), as well as in normal skin exposed or not exposed to sunlight. Immunohistochemical analyses showed that OPN is expressed in SCC (20/20 cases) and in AK (16/16 cases), which are precursors to SCC, but is absent or minimally expressed in solid BCC (17 cases). However, positive staining for OPN was observed in those BCC that manifest differentiation toward epidermal appendages such as keratotic BCC. In sunlight-exposed normal skin, OPN is minimally expressed in the basal cell layer, but in contrast to those not exposed to sunlight, OPN is more prominent in the spinous cell layer with increasing intensity toward the granular cell layer. Additionally, OPN is expressed in the hair follicles, sebaceous glands, and sweat glands of normal skin. In conclusion, these data suggest that OPN is associated with keratinocyte differentiation and that it is expressed in AK and SCC, which have metastatic potential, but minimally expressed in solid BCC.

Papilloma development is delayed in osteopontin-null mice: implicating an antiapoptosis role for osteopontin.

Osteopontin is a secreted, adhesive glycoprotein, whose expression is markedly elevated in several types of cancer and premalignant lesions, implicating its association with carcinogenesis. To test the hypothesis that induced osteopontin is involved in tumor promotion in vivo, osteopontin-null and wild-type (WT) mice were subjected to a two-stage skin chemical carcinogenesis protocol. Mice were initiated with 7,12-dimethylbenz(a)anthracene (DMBA) applied on to the dorsal skin followed by twice weekly application of 12-O-tetradecanoylphorbol-13-acetate (TPA) for 27 weeks. Osteopontin-null mice showed a marked decrease both in tumor/papilloma incidence and multiplicity compared with WT mice. Osteopontin is minimally expressed in normal epidermis, but on treatment with TPA its expression is highly induced. To determine the possible mechanism(s) by which osteopontin regulates tumor development, we examined cell proliferation and cell survival. Epidermis from osteopontin-null and WT mice treated with TPA thrice or with DMBA followed by TPA for 11 weeks showed a similar increase in epidermal hyperplasia, suggesting that osteopontin does not mediate TPA-induced cell proliferation. Bromodeoxyuridine staining of papillomas and adjacent epidermis showed no difference in cell proliferation between groups. However, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling analyses indicated a greater number of apoptotic cells in DMBA-treated skin and papillomas from osteopontin-null versus WT mice. These studies are the first to show that induction of the matricellular protein osteopontin facilitates DMBA/TPA-induced cutaneous carcinogenesis most likely through prevention of apoptosis.

Tumor regression by expression of high physiological levels of EBV latent membrane protein 1.

Induction of apoptosis in tumor cells is one of therapeutic strategies of cancer. Previous studies indicate that LMP-1 can act as governor of cell proliferation because overexpression of latent membrane protein 1 (LMP-1) of Epstein-Barr virus (EBV) inhibits cell proliferation. Here we demonstrate that overexpression of the NLMP-1, isolated from an EBV strain prominent in Taiwanese population, also possess the ability to induce apoptosis of cells, and inhibit CT-26 tumor growth in mice. Mapping studies indicate that NLMP-1 transmembrane domain is required for induction of cytotoxicity. Intratumoral delivery of vectors expressing NLMP-1 or its membrane domain via electroporation induces tumor tissue damage, suppresses tumor growth in mice, and prolongs the survival of treated animals. In addition, the membrane domain of NLMP-1 alone induces effects similar to those induced by cotreatment with NLMP-1 and IL-12. Tumor-free mice at 120 days after the initial treatments were further challenged with CT-26 tumor cells. No tumor growth was observed. Thus, NLMP-1, and more specifically the transmembrane domain of NLMP-1, may be promising new therapeutic agents for control of tumor growth.

Electroporation-mediated and EBV LMP1-regulated gene therapy in a syngenic mouse tumor model.

Latent membrane protein 1 (LMP1) is an Epstein-Barr virus (EBV)-encoded oncogene expressed in EBV-associated nasopharyngeal carcinoma (NPC). Previous studies indicate that a strategy combining LMP1-mediated NF-kappaB activation and the HSV thymidine kinase/Ganciclovir (HSVtk/GCV) prodrug system leads to regression of tumor growth in nude mice. To improve the efficacy of this strategy in immunocompetent hosts, we developed a therapeutic cassette, p6kappaB-EDL1E-tk, containing six copies of the NF-kappaB binding motif and an epithelial-specific EBV promoter, ED-L1E. The cassette was tested in a murine CT-26 carcinoma model in syngenic Balb/c mice. Coinjection of an LMP1-expressing vector and p6kappaB-EDL1E-tk by in vivo electroporation in mouse muscle revealed at least two-fold higher TK enzymatic activity than that of previously tested pLTR-tk. Furthermore, growth was attenuated in a group of mice containing LMP1-positive tumors that were intratumorally injected with the p6kappaB-EDL1E-tk cassette and GCV via in vivo electroporation, but not in mice treated with p6kappaB-EDL1E-tk or GCV alone. Similarly, no retardation of tumor growth was observed in mice containing LMP1-negative CT-26 tumors injected with both the p6kappaB-EDL1E-tk cassette and GCV. We propose that intratumoral injection of therapeutic agents, such as DNA of transcription-regulated cassette and GCV, via in vivo electroporation may be used as an alternative treatment for EBV LMP1-expressing cancers.