Alpha-lipoic acid effectively attenuates ionizing radiation-mediated testicular dysfunction in rats: Crosstalk of NF-ĸB, TGF-ß, and PPAR-ϒ pathways.

Radiotherapy is one of the principal approaches employed in the treatment of pelvic cancers. Nevertheless, testicular dysfunction and infertility are among the most common adverse effects in young adult cancer survivors. Clinically, alpha-lipoic acid (LA) has been applied to improve the quality of sperm with a satisfactory effect. Therefore, the present study investigated the underlying mechanisms of the radioprotective effects of LA against testicular damage. Male Sprague-Dawley rats were exposed to 10 Gy of whole-body ϒ-radiation and LA (50 mg/kg, P.O.) was administered one week before and three days post-irradiation. LA showed remarkable capacity in preserving testicular tissue against radiation damage by improving histological and ultrastructural changes of disorganized seminiferous tubules, besides enhancing its diameter, germinal epithelial thickness, and Johnsen's score. Radiation instigated a significant decrease in sperm quality and quantity associated with depletion of serum testosterone levels, while the LA administration maintained spermatogenesis. Strikingly, LA exhibited antioxidant properties by restoring reduced glutathione levels and antioxidant enzyme activities such as catalase and glutathione-s-transferase, besides diminishing malondialdehyde levels in the testis of irradiated group. Furthermore, LA alleviated testicular inflammation through downregulation of nuclear factor-ĸB (NF-ĸB) expression with a subsequent reduction in interleukin (IL)-6 and cyclooxygenase-2 expression, accompanied by the augmented expression of the anti-inflammatory cytokine IL-10. Additionally, testicular fibrosis markers including Masson's trichrome and transforming growth factor (TGF)-ß expression were noticeably declined in LA-treated irradiated rats, together with the upregulation of peroxisome proliferator-activated receptor-ϒ expression. Collectively, LA ameliorates radiation-mediated spermatogenesis-defects and testicular-damage via suppression of oxidative stress/NF-ĸB/TGF-ß signaling.

Radio resistance in breast cancer cells is mediated through TGF-ß signalling, hybrid epithelial-mesenchymal phenotype and cancer stem cells.

AIMS: A major obstacle for effective cancer treatment by radiation therapy is the development of radio-resistance and identification of underlying mechanisms and activated pathways will lead to better combination therapies. MAIN METHODS: Irradiated MCF-7 and MDA-MB-231 breast cancer cell lines were characterised following different recovery periods. Proliferation was assessed by MTT, BrdU and clonogenic assays and apoptosis by Annexin V/ propidium iodide staining and flow cytometry. Gene expression was monitored by real time PCR/ELISA/antibody labelling and migration using transwell inserts. KEY FINDINGS: Breast cancer cell lines exposed to 6 Gy followed by recovery period for 7 days (D7-6 G) had increased ability for proliferation as well as apoptosis. D7-6 G from both cell lines had increased expression of transforming growth factor isoforms (TGF)-ß1, ß2 and ß3, their receptors TGF-ßR1 and TGF-ßR2 which are known for such dual effects. The expression of downstream transcription factors Snail, Zeb-1 and HMGA2 also showed a differential pattern in D7-6 G cells with upregulation of at least two of these transcription factors. D7-6 G cells from both cell lines displayed hybrid epithelial-mesenchymal (E/M) phenotype with increased expression of E/M markers and migration. D7-6 G cells had increased expression of cancer stem cells markers Oct4, Sox2, and Nanog; aldehyde dehydrogenase expression and activity; proportion of CD44+CD24-cells. This was accompanied by radio resistance when exposed to a challenge dose of radiation. Treatment with TGF-ßRI inhibitor abrogated the increase in proliferation of D7-6 G cells. SIGNIFICANCE: Blocking of TGF-ß signalling may therefore be an effective strategy for overcoming radio resistance induced by radiation exposure.

High-Fluence Light-Emitting Diode-Generated Red Light Modulates the Transforming Growth Factor-Beta Pathway in Human Skin Fibroblasts.

BACKGROUND: Skin fibrosis is a significant medical problem with limited available treatment modalities. The key cellular characteristics include increased fibroblast proliferation, collagen production, and transforming growth factor-beta (TGF-B)/SMAD pathway signaling. The authors have previously shown that high-fluence light-emitting diode red light (HF-LED-RL) decreases cellular proliferation and collagen production. OBJECTIVE: Herein, the authors investigate the ability of HF-LED-RL to modulate the TGF-B/SMAD pathway. MATERIALS AND METHODS: Normal human dermal fibroblasts were cultured and irradiated with a commercially available hand-held LED array. After irradiation, cell lysates were collected and levels of pSMAD2, TGF-Beta 1, and TGF-Beta I receptor were measured using Western blot. RESULTS: High-fluence light-emitting diode red light decreased TGF-Beta 1 ligand (TGF-B1) levels after irradiation. 320 J/cm HF-LED-RL resulted in 59% TGF-B1 and 640 J/cm HF-LED-RL resulted in 54% TGF-B1, relative to controls. 640 J/cm HF-LED-RL resulted in 62% pSMAD2 0 hours after irradiation, 65% pSMAD2 2 hours after irradiation, and 95% 4 hours after irradiation, compared with matched controls. High-fluence light-emitting diode red light resulted in no significant difference in transforming growth factor-beta receptor I levels compared with matched controls. CONCLUSION: Skin fibrosis is a significant medical problem with limited available treatment modalities. Light-emitting diode-generated red light is a safe, economic, and noninvasive modality that has a body of in vitro evidence supporting the reduction of key cellular characteristics associated with skin fibrosis.

UV radiation promotes melanoma dissemination mediated by the sequential reaction axis of cathepsins-TGF-ß1-FAP-α.

BACKGROUND: Ultraviolet radiation (UVR) is the major risk factor for development of malignant melanoma. Fibroblast activation protein (FAP)-α is a serine protease expressed on the surface of activated fibroblasts, promoting tumour invasion through extracellular matrix (ECM) degradation. The signalling mechanism behind the upregulation of FAP-α is not yet completely revealed. METHODS: Expression of FAP-α was analysed after UVR exposure in in vitro co-culture systems, gene expression arrays and artificial skin constructs. Cell migration and invasion was studied in relation to cathepsin activity and secretion of transforming growth factor (TGF)-ß1. RESULTS: Fibroblast activation protein-α expression was induced by UVR in melanocytes of human skin. The FAP-α expression was regulated by UVR-induced release of TGF-ß1 and cathepsin inhibitors prevented such secretion. In melanoma cell culture models and in a xenograft tumour model of zebrafish embryos, FAP-α mediated ECM degradation and facilitated tumour cell dissemination. CONCLUSIONS: Our results provide evidence for a sequential reaction axis from UVR via cathepsins, TGF-ß1 and FAP-α expression, promoting cancer cell dissemination and melanoma metastatic spread.

Effects of high power-pulsed Nd:YAG laser irradiation on the release of transforming growth factor-beta (TGF-ß) and vascular endothelial growth factor (VEGF) from human gingival fibroblasts.

The purpose of this study was to investigate the effect of different high-power energy settings of a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (1064 nm) on cell viability of human gingival fibroblasts (GFs) and release of transforming growth factor-beta (TGF-ß) and vascular endothelial growth factor (VEGF) on these cells. GFs were isolated from human gingival connective tissues during the crown lengthening procedure. GFs were irradiated with different laser parameters as follows: group 1: 1 W (100 mJ, 10 Hz) 10 seconds; group 2: 1.5 W (150 mJ, 10 Hz) 10 seconds; group 3: 2 W (200 mJ, 10 Hz) 10 seconds; group 4: 1 W (100 mJ, 10 Hz) 20 seconds; group 5: 1.5 W (150 mJ, 10 Hz) 20 seconds; and group 6: 2 W (200 mJ, 10 Hz) 20 seconds. Cell viability/cell proliferation was analyzed with XTT (tetrazolium salt, cell proliferation kit) staining. The release levels of TGF-ß and VEGF were analyzed by the enzyme-linked immunosorbent assay. No significant differences were observed in the different laser irradiation groups compared to the control group in terms of cell viability (p > 0.05). The release of TGF-ß was not affected by different laser irradiation settings (p > 0.05). Only group 6 promoted significantly higher VEGF release from GFs in 24 hours compared to the control group (p ˂ 0.05). These findings suggest that high-power Nd:YAG laser is probably safe but has a very limited effect for wound healing.

Expresión de TGFß1 por fibroblastos de mucosa oral expuestos a radiación ultravioleta B / TGF1 expression by oral mucosa fibroblasts exposed to ultraviolet ß1 radiation

El objetivo de este estudio fue evaluar el efecto de la radiación ultravioleta (UV) B sobre la expresión del factor de crecimiento transformante (TGF) ß1 por fibroblastos de mucosa oral, con el objetivo de dilucidar si este tipo celular puede contribuir a la expresión de TGFß1 en bermellón labial sobreexpuesto a la radiación UV. Se obtuvieron cultivos primarios de fibroblastos desde explantes de mucosa bucal, los que fueron irradiados con una dosis única de luz UVB (60 mJ/cm2). Se midió proliferación celular con el método MTT, y la expresión de TGFß1, a nivel de ARN mensajero (normalizado a GAPDH) por RT-PCR y a nivel de proteína mediante inmunofluorescencia. Se observó una disminución de la proliferación celular de los fibroblastos de mucosa oral a las 24 hrs post-irradiación en relación a los fibroblastos no irradiados (P<0,05, Mann Whitney). No se encontraron diferencias entre los fibroblastos control y los irradiados en la expresión de TGFß-1 ni a nivel de mensajero (0,5 y 6 h post-irradiación), ni de proteína (24 h post-irradiación). Los resultados sugieren que los fibroblastos de mucosa oral presentan una disminución de su proliferación en respuesta a una dosis única de radiación UVB, sin que se afecte la expresión de TGFß-1, la que fue similar a los fibroblastos no irradiados. Esto sugiere que los fibroblastos contribuirían a la producción de TGFß-1 en respuesta a la exposición crónica a UVB del bermellón labial.

The objective of this study was to characterize the effect of Ultraviolet (UV) B irradiation on the expression of transforming growth factor (TGF) ß1 by oral mucosa fibroblasts, in order to assess if these cells contribute to the production of TGFß-1 in UV-irradiated lip vermillion. Primary cultures of fibroblasts were obtained from oral mucosa explants, and were irradiated with a single dose of UVB light (60 mJ/cm2). The effects of UVB radiation on cell proliferation was evaluated by the MTT method. The effects of UVB on the expression of TGF-ß1 was analyzed by RT-PCR (normalized to GAPDH) and by immunofluorescence. The results showed a decrease in the proliferation of UVB-irradiated fibroblasts as compared to controls at 24h post-irradiation (p<0.05). No variations in the expression of TGFß1, both at the mRNA and protein level, were observed between control and UVB-irradiated fibroblasts during the first 24 h after irradiation. Oral mucosa fibroblasts have reduced proliferation in response to a single dose of UVB, but their expression of TGFß1 was not affected. This suggests that oral mucosa fibroblasts may contribute to the production of TGFß1 in the lip vermillion independent of UVB exposure.

Blood and lymphatic microvessel damage in irradiated human skin: The role of TGF-ß, endoglin and macrophages.

BACKGROUND AND PURPOSE: Microvascular damage is an important component of late radiation-induced morbidity. In our pre-clinical models, we demonstrated that repair of vessel injury is dependent on proper endoglin-mediated transforming growth factor-beta (TGF-ß) signalling and that it can be affected by infiltrating macrophages. We now wanted to extend these findings in irradiated patients, using skin as a model system, and assess whether bisphosphonates could modulate the response. MATERIALS AND METHODS: Paired skin biopsies from irradiated and non-irradiated sites were obtained from 48 breast cancer patients. In 8 patients, biopsies were repeated after 4months of bisphosphonate treatment. Immunohistochemistry was used to assess vascular alterations and leucocyte infiltration. Western Blot and qPCR were used to assess expression of growth factors and their receptors. RESULTS: Decreased blood vessel numbers at early time points were followed by increased endoglin expression and restoration of vessel number. Loss of small lymphatic vessels was associated with increased TGF-ß levels, whereas dilation of lymphatic vessels correlated with increased macrophage infiltration. Bisphosphonate treatment reduced leucocyte infiltration, but also prevented restoration of blood vessel numbers after irradiation. CONCLUSION: Radiation injury of the microvasculature is mediated through TGF-ß, whereas repair is modulated by the co-receptor endoglin and promoted by macrophages.

Visible red and infrared light alters gene expression in human marrow stromal fibroblast cells.

OBJECTIVES: This study tested whether or not gene expression in human marrow stromal fibroblast (MSF) cells depends on light wavelength and energy density. MATERIALS AND METHODS: Primary cultures of isolated human bone marrow stem cells (hBMSC) were exposed to visible red (VR, 633 nm) and infrared (IR, 830 nm) radiation wavelengths from a light emitting diode (LED) over a range of energy densities (0.5, 1.0, 1.5, and 2.0 Joules/cm2) Cultured cells were assayed for cell proliferation, osteogenic potential, adipogenesis, mRNA and protein content. mRNA was analyzed by microarray and compared among different wavelengths and energy densities. Mesenchymal and epithelial cell responses were compared to determine whether responses were cell type specific. Protein array analysis was used to further analyze key pathways identified by microarrays. RESULT: Different wavelengths and energy densities produced unique sets of genes identified by microarray analysis. Pathway analysis pointed to TGF-beta 1 in the visible red and Akt 1 in the infrared wavelengths as key pathways to study. TGF-beta protein arrays suggested switching from canonical to non-canonical TGF-beta pathways with increases to longer IR wavelengths. Microarrays suggest RANKL and MMP 10 followed IR energy density dose-response curves. Epithelial and mesenchymal cells respond differently to stimulation by light suggesting cell type-specific response is possible. CONCLUSIONS: These studies demonstrate differential gene expression with different wavelengths, energy densities and cell types. These differences in gene expression have the potential to be exploited for therapeutic purposes and can help explain contradictory results in the literature when wavelengths, energy densities and cell types differ.

Carbon nanotube-assisted optical activation of TGF-ß signalling by near-infrared light.

Receptor-mediated signal transduction modulates complex cellular behaviours such as cell growth, migration and differentiation. Although photoactivatable proteins have emerged as a powerful tool for controlling molecular interactions and signalling cascades at precise times and spaces using light, many of these light-sensitive proteins are activated by ultraviolent or visible light, which has limited tissue penetration. Here, we report a single-walled carbon nanotube (SWCNT)-assisted approach that enables near-infrared light-triggered activation of transforming growth factor ß (TGF-ß) signal transduction, an important signalling pathway in embryonic development and cancer progression. The protein complex of TGF-ß and its latency-associated peptide is conjugated onto SWCNTs, where TGF-ß is inactive. Upon near-infrared irradiation, TGF-ß is released through the photothermal effect of SWCNTs and becomes active. The released TGF-ß activates downstream signal transduction in live cells and modulates cellular behaviours. Furthermore, preliminary studies show that the method can be used to mediate TGF-ß signalling in living mice.

The HPV16 E6 oncoprotein and UVB irradiation inhibit the tumor suppressor TGFß pathway in the epidermis of the K14E6 transgenic mouse.

High-risk human papillomaviruses (HR-HPVs) are the causative agents of cervical cancer, and they are also associated with a subset of head and neck squamous cell carcinomas. In addition, HPVs have also been postulated in the development of non-melanoma skin cancers (NMSC). In these cancers, the oncogene E6 is best known for its ability to inactivate the tumor suppressor p53 protein. Interestingly, in transgenic mice for HPV16 E6 (K14E6), it was reported that E6 alone induced epithelial hyperplasia and delay in differentiation in skin epidermis independently of p53 inactivation. Transforming growth factor ß (TGFß) is an important regulator of cell growth/differentiation and apoptosis, and this pathway is often lost during tumorigenesis. Ultraviolet radiation B (UVB) exposure activates diverse cellular responses, including DNA damage and apoptosis. In this study, we investigated whether the E6 oncogene alone or in combination with UVB dysregulate some components of the TGFß pathway in the epidermis of K14E6 mice. We used 8-day-old K14E6 and non-transgenic mice irradiated and unirradiated with a single dose of UVB. We found that the E6 oncogene and UVB irradiation impair the TGFß pathway in epidermis of K14E6 mice by downregulation of the TGFß type II receptor (TßRII). This loss of TßRII prevents downstream activation of Smad2 and target genes as p15, an important regulator of cell cycle progression. In summary, the TGFß signalling in cells of the epidermis is downregulated in our mouse model by both the E6 oncoprotein and the UVB irradiation.

Influence of smartphone Wi-Fi signals on adipose-derived stem cells.

The use of smartphones is expanding rapidly around the world, thus raising the concern of possible harmful effects of radiofrequency generated by smartphones. We hypothesized that Wi-Fi signals from smartphones may have harmful influence on adipose-derived stem cells (ASCs). An in vitro study was performed to assess the influence of Wi-Fi signals from smartphones. The ASCs were incubated under a smartphone connected to a Wi-Fi network, which was uploading files at a speed of 4.8 Mbps for 10 hours a day, for a total of 5 days. We constructed 2 kinds of control cells, one grown in 37°C and the other grown in 39°C. After 5 days of Wi-Fi exposure from the smartphone, the cells underwent cell proliferation assay, apoptosis assay, and flow cytometry analysis. Three growth factors, vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor-ß, were measured from ASC-conditioned media. Cell proliferation rate was higher in Wi-Fi-exposed cells and 39°C control cells compared with 37°C control cells. Apoptosis assay, flow cytometry analysis, and growth factor concentrations showed no remarkable differences among the 3 groups. We could not find any harmful effects of Wi-Fi electromagnetic signals from smartphones. The increased proliferation of ASCs under the smartphone, however, might be attributable to the thermal effect.

Histological and radiographic evaluation of the muscle tissue of rats after implantation of bone morphogenic protein (rhBMP-2) in a scaffold of inorganic bone and after stimulation with low-power laser light.

OBJECTIVE: The present study histologically and radiologically evaluates the muscle tissue of rats after implantation of bone morphogenic protein (rhBMP-2) in a natural inorganic bone mineral scaffold from a bull calf femur and irradiation with low-power light laser. MATERIALS AND METHODS: The right and left hind limbs of 16 rats were shaved and an incision was made in the muscle on the face corresponding to the median portion of the tibia, into which rhBMP-2 in a scaffold of inorganic bone was implanted. Two groups of limbs were formed: control (G1) and laser irradiation (G2). G2 received diode laser light applied in the direction of the implant, at a dose of 8 J/cm2 for three minutes. On the 7th, 21st, 40th and 112th days after implantation, hind limbs of 4 animals were radiographed and their implants removed together with the surrounding tissue for study under the microscope. The histological results were graded as 0=absence, 1=slight presence, 2=representative and 3=very representative, with regard to the following events: formation of osteoid structure, acute inflammation, chronic inflammation, fibrin deposition, neovascularization, foreign-body granuloma and fibrosis. RESULTS: There were no statistically significant differences in these events at each evaluation times, between the two groups (P > 0.05; Mann-Whitney test). Nevertheless, it could be concluded that the natural inorganic bone matrix with rhBMP-2, from the femur of a bull calf, is a biocompatible combination. CONCLUSIONS: Under these conditions, the inductive capacity of rhBMP-2 for cell differentiation was inhibited. There was a slight acceleration in tissue healing in the group that received irradiation with low-power laser light.

Late changes in cutaneous gene expression patterns after adjuvant treatment of oral squamous cell carcinoma (OSCC) by radiation therapy.

OBJECTIVE: The objective of this study was to investigate radiation-induced late changes in cutaneous gene expression using a microarray platform and quantitative, real-time, reverse-transcriptase polymerase chain reaction (RT-PCR) validation. STUDY DESIGN: Paired irradiated and nonirradiated skin biopsies were obtained from 19 patients with a history of oral squamous cell carcinoma (OSCC) treated by surgery and adjuvant radiotherapy at the time of secondary corrective surgery. Topic-defined PIQOR (Parallel Identification and Quantification of RNAs) skin microarrays were used to compare gene expression profiles between control and irradiated skin sample in 8 patients. The data were validated for matrixmetalloproteinase (MMP)-1 and tissue-inhibitor of matrixmetalloproteinase (TIMP)-1 by RT-PCR for all patients. RESULTS: Irradiation markedly enhanced the expression of molecules associated with the transforming growth factor (TGF)-beta(1) signaling pathway, blood vessel development, as well as extracellular matrix constitution and turn-over. CONCLUSIONS: Our data suggest that radiation-induced late changes in cutaneous gene expression mainly affect molecules related to extracellular matrix (ECM)-constitution and-remodeling.

Inhibition of transforming growth factor-beta, hypoxia-inducible factor-1alpha and vascular endothelial growth factor reduced late rectal injury induced by irradiation.

Tumor hypoxia and angiogenesis associated with malignant progression have been studied widely. The efficacy of angiogenesis inhibition combined with radiotherapy has been demonstrated in cancer treatment. Here, we studied the effect of hypoxia and angiogenesis inhibition on radiation-induced late rectal injury. The rectum of C57BL/6N mice was irradiated locally with a single dose of 25 Gy. Radiation-induced histological changes were examined at 90 days after irradiation by hematoxylin-eosin (H.E.) staining and azan staining. Pimonidazole was administered and its distribution was assayed by immunohistochemistry staining. Expression of transforming growth factor beta1 (TGF-beta1), hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) was assessed on the fibrotic region using real-time PCR and immunohistochemistry. In addition, the effects of TGF-beta, VEGF and HIF-1alpha on radiation-induced injury were investigated by the administration of neutralizing antibody of TGF-beta, antibody of VEGF or YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole) which was developed as an agent for inhibiting HIF-1 expression after irradiation respectively. Fibrosis and uptake of pimonidazole were found 90 days after irradiation. The expression of TGF-beta1, HIF-1alpha and VEGF significantly increased with the formation of fibrosis induced by irradiation compared with unirradiated controls. In addition, treatment of neutralizing antibody of TGF-beta, antibody of VEGF or YC-1 reduced the development of radiation-induced injury. Our results suggested that radiation-induced hypoxia may play an important role in late rectal injury. Although the inhibition of HIF-1alpha and VEGF reduced the radiation induced late injury, the precise mechanism is still unclear.

Effects of Smads and BMPs induced by Ga-Al-As laser irradiation on calcification ability of human dental pulp cells.

We investigated the effects of Ga-Al-As laser irradiation on the mineralization ability of human dental pulp (HDP) cells and on Smads and bone morphogenetic protein (BMP) production as one mechanism for the transmission of laser photochemical energy to cells. HDP cells in vitro were irradiated once with a Ga-Al-As laser at 1.0 W for 500 s, and calcified nodule formation was assessed by Alizarin red S staining. The laser irradiation was greater in the laser-irradiated group than in the non-irradiated group. Both calcium production and alkaline phosphatase (ALP) activity were higher after laser irradiation. Expression of mRNAs for Smad1, Smad7, BMPs, ALP, and osteocalcin was greater after laser irradiation, whereas expression of Smad6 mRNA was inhibited. Production of BMP-2 and BMP-4 in conditioned medium was also higher after laser irradiation. These results suggest that Smads and BMPs play important roles in ALP activity and calcification upon laser irradiation of HDP cells.

Activation of latent TGF-beta1 by low-power laser in vitro correlates with increased TGF-beta1 levels in laser-enhanced oral wound healing.

The term Laser "Photobiomodulation" was coined to encompass the pleiotropic effects of low-power lasers on biological processes. The purpose of this study was to investigate whether transforming growth factor (TGF)-beta had a role in mediating the biological effects of low-power far-infrared laser irradiation. We assayed for in vitro activation using various biological forms of cell-secreted, recombinant, and serum latent TGF-beta using the p3TP reporter and enzyme-linked immunosorbent assays. We demonstrate here that low-power lasers are capable of activating latent TGF-beta1 and -beta3 in vitro and, further, that it is capable of "priming" these complexes, making them more amenable to physiological activation present in the healing milieu. Using an in vivo oral tooth extraction-healing model, we observed an increased TGF-beta1, but not beta3, expression by immunohistochemistry immediately following laser irradiation while TGF-beta3 expression was increased after 14 days, concomitant with an increased inflammatory infiltrate. All comparisons were performed between laser-irradiated wounds and nonirradiated wounds in each subject essentially using them as their own control (paired T-test p<0.05). Low-power laser irradiation is capable of activating the latent TGF-beta1 complex in vitro and its expression pattern in vivo suggests that TGF-beta play a central role in mediating the accelerated healing response.

Significant downregulation of transforming growth factor-beta signal transducers in human skin following ultraviolet-A1 irradiation.

BACKGROUND: Despite the significant role of the transforming growth factor (TGF)-beta/Smad pathway in cell growth and extracellular matrix regulation, relatively little is known regarding the effect of ultraviolet (UV) radiation on the TGF-beta/Smad signalling in human skin. OBJECTIVES: We aimed to investigate the impact of UVA1 and UVB on the mRNA and protein expression of TGF-beta/Smad signal transducers in human skin in vivo. METHODS: Fifteen subjects were exposed to 1.5 minimal erythema doses (MED) (4.5 MED cumulative) of UVA1 and UVB over a 3-day period. Skin biopsies were obtained at 24 and 72 h after the last UV exposure. Real-time reverse transcription-polymerase chain reaction and immunohistology were performed. RESULTS: In the UVA1-exposed sites (24 h, 72 h), mRNA expression of TGF-beta1 and Smad3/4/7 was significantly downregulated as compared with nonirradiated skin sites (P < 0.05). At 24 h, immunohistology revealed significantly reduced TGF-beta1 protein levels in fibroblasts (P < 0.05). However, mRNA and protein expression of TGF-beta/Smad proteins observed in UVB-irradiated sites did not differ significantly from control sites (P > 0.05). CONCLUSIONS: In contrast to UVB, UVA1 significantly downregulates the expression of TGF-beta/Smad proteins in human skin in vivo. The extent to which the acute effects of TGF-beta/Smad signalling reported in the present paper are related to the beneficial effect of UVA1-based phototherapy of fibrotic skin conditions and/or to the chronic effects of UV that result in photoaging and cancer remains to be established.

Extracellular matrix alterations in conventional renal cell carcinomas by tissue microarray profiling influenced by the persistent, long-term, low-dose ionizing radiation exposure in humans.

The present study was carried out in order to examine molecular alterations of extracellular matrix (ECM), associated with cell-cell communication in conventional (clear-cell) renal cell carcinomas (cRCCs) influenced by persistent long-term, low-dose ionizing radiation (IR) exposure to patients living more than 19 years after the Chernobyl accident in Cesium 137 (137Cs)-contaminated areas of Ukraine. The ECM major components such as fibronectin, laminin, E-cadherin/beta-catenin complexes and p53 tumor suppressor gene protein, and transforming growth factor beta 1 (TGF-beta1) were immunohistochemically (IHC) evaluated in cRCCs from 59 Ukrainian patients, which represented 18 patients living in non-contaminated areas and 41 patients from 137Cs-contaminated areas. In contrast, a control group of 19 Spanish patients with analogue tumors were also investigated. For IHC evaluation, a tissue microarray technique was used. Decrease or loss and abnormal distribution of fibronectin, laminin, E-cadherin/beta-catenin complexes accompanied by elevated levels of p53 and TGF-beta1 were detected in the Ukrainian cRCCs from 137Cs-contaminated areas with statistically significant differences. Thus, our study suggests that chronic long-term, low-dose IR exposure might result in global remodeling of ECM components of the cRCCs with disruption in peri-epithelial stroma and epithelial basement membranes.

Differential expression of melanoma-associated growth factors in keratinocytes and fibroblasts by ultraviolet A and ultraviolet B radiation.

BACKGROUND: Besides the direct DNA-damaging effects of ultraviolet (UV) radiation on cells, indirect effects on the microenvironment of the skin may facilitate melanoma development. A stimulation of growth factor production by cells in the immediate environment of melanocytes may lead to a paracrine activation and proliferation of melanocytes that in turn become more susceptible to transformation. OBJECTIVES: We investigated whether the expression of growth factors for melanocytes can be modulated in keratinocytes and fibroblasts by UVA or UVB. METHODS: After irradiation with different doses of UVA or UVB, protein expression of basic fibroblast growth factor (bFGF), endothelin (ET)-1, transforming growth factor (TGF)-beta1, platelet-derived growth factor (PDGF)-AA, stem cell factor (SCF) and hepatocyte growth factor (HGF) was analysed by quantitative enzyme-linked immunosorbent assay. The mRNA expression of bFGF and ET-1 was analysed by quantitative real-time reverse transcriptase-polymerase chain reaction. RESULTS: In keratinocytes, UVB and UVA increased bFGF protein levels up to 2.6-fold. This increase was paralleled by elevated mRNA levels. UVB also induced ET-1 protein up to 1.8-fold, while UVA led to an 80% decrease. Secreted TGF-beta1 and PDGF-AA were downregulated by UVA by less than 50%, while there was no significant alteration by UVB. Secreted SCF was not changed significantly by UVA or UVB. In fibroblasts, bFGF protein levels were increased 11-64-fold by UVA and 34-61-fold by UVB. This was paralleled by elevated mRNA levels for bFGF up to 2.7-fold. HGF protein was stimulated by UVA up to 2.8-fold and by UVB up to 6.7-fold, while TGF-beta1 protein was increased up to 2.7-fold by UVB and 1.7-fold by UVA. CONCLUSIONS: UVA and UVB can stimulate and inhibit the production of growth factors for melanocytes in keratinocytes and fibroblasts dependent on the cell type and wavelength. We show for the first time that UVA and UVB can activate bFGF, HGF and TGF-beta1 in fibroblasts, while bFGF was the most inducible factor both in fibroblasts and in keratinocytes. The induction of bFGF and HGF in fibroblasts by UVA suggests that stroma cells in the dermis may be involved in the UV activation of melanocytes via paracrine ways and thus promote melanoma development.

Effect of beta radiation on TGF-beta1 and bFGF expression in hyperplastic prostatic tissues.

AIM: To investigate the transforming growth factor beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) expressions in benign prostatic hyperplasia (BPH) and the effect of beta-radiation. METHODS: TGF-beta1 and bFGF expression was studied by means of an immunohistochemical method in nine normal prostatic (NP) tissues, 15 hyperplastic prostatic tissues and 35 hyperplastic prostatic tissues treated with 90Sr/90Y. RESULTS: The TGF-beta1 expression in the epithelium and stroma of normal prostatic tissues was 68.2 % +/- 10.5 % and 29.7 % +/- 4.6 %, respectively, while it was 64.8 % +/- 9.3 % and 28.6 % +/- 4.1 %, respectively, in hyperplastic prostatic tissues. Compared with the controls, TGF-beta1 expression in the epithelia and stroma of BPH treated with 90Sr/90Y increased significantly (P <0.01). The bFGF expression in epithelia and stroma of normal prostatic tissues was 17.4 % +/- 3.7 % and 42.5 % +/- 6.8 %, respectively, and was 46.3 % +/- 8.2 % and 73.2 % +/- 12.1 %, respectively, in hyperplastic prostatic tissues. Compared with the controls, expressions of bFGF in the epithelia and stroma of BPH treated with a 90Sr/90Y prostatic hyperplasia applicator decreased significantly (P <0.01). CONCLUSION: Exposure of beta-rays had noticeable effects on BPH tissues, enhancing TGF-beta1 expression and inhibiting bFGF expression.