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To analyze the effectiveness and safety of zoledronic acid combined with chemotherapy for lung cancer spinal metastases, 96 patients with lung cancer spinal metastases were averagely classified into the experimental group (gemcitabine, cisplatin, and zoledronic acid) and the control group (gemcitabine and cisplatin). An optimized noise variance estimation algorithm (OMAPB) was proposed based on the maximum a posteriori Bayesian method (MAPB), and the algorithm was applied to the patient’s computed tomography (CT) scan. The results indicated that in terms of curative effect, the number of complete remission (CR), partial remission (PR) cases, effective rate, and clinical benefit rate of the test group was significantly higher than those of the control group. The number of progress disease (PD) cases was significantly lower than that of the control group ( P < 0.05 ). The disease progression time of the test group patients was 6.2 months, and the disease progression time of the control group patients was 3.7 months ( P < 0.05 ). The test group patients had 8 cases of bone marrow suppression and gastrointestinal reactions after treatment. In the test group, there were 8 cases of bone marrow suppression, 9 cases of gastrointestinal reaction, 3 cases of fever, 4 cases of pain, and 2 cases of hair loss. The patients in the control group were complicated with bone marrow suppression in 14 cases, gastrointestinal reaction in 17 cases, fever in 5 cases, pain in 4 cases, and hair loss in 6 cases. The difference was statistically significant ( P < 0.05 ). It showed that zoledronic acid combined with chemotherapy could effectively improve the treatment efficiency and clinical benefit rate of patients with lung cancer spinal metastases, prolong the progression of the disease, reduce the degree of bone tissue damage, and would not increase chemotherapy adverse events.

Magnesium (Mg) matrix composites have the potential to improve energy efficiency and system performance in aerospace, automobile, mobile electronics and biomedical applications. In this work, a novel graphene nanoplatelets (GNPs) reinforced Mg matrix composites with the bimodal microstructure have been fabricated. The combination of bubbles assisted assembly method, liquid metallurgy process and hot extrusion was developed to smash the agglomeration of nanoplatelets and construct the bimodal microstructure of the Mg/GNPs composites. The theoretical calculation for strengthening mechanisms showed that the enhanced strength of the composites were mainly contributed by the grain refinement effect and the load transfer effect by GNPs. Because of the concave function relationship between the grain size and the corresponding increased yield strength, the bimodal microstructure significantly improved the strengthening efficiency of the composites, which was superior to the composites with uniform refined grains. This behavior demonstrated new possibilities for scientific and technological advantages with architecture design of composites.

The retinoic acid-related orphan receptors alpha (RORa) are members of the steroid/thyroid nuclear receptor super-family and core components of the circadian timing system. In the present study, we continue to investigate the role of RORas in human breast cancer. Assays using the RORa response element (RORE)-tk-luciferase reporter demonstrate the functionality of the RORa1 in MCF-7 breast cancer cells and that over-expression of RORa1 stimulates MCF-7 human breast cancer cell proliferation. Genomic analysis revealed that RORα1 over-expression regulated the transcription of numerous genes in MCF-7 breast cancer cells including increasing the expression of connexin 43 (CX43), aldo-keto reductases 1C1 (AKR1C1), and AKR1C3. Furthermore, administration of the pineal hormone melatonin represses RORa1 induction of CX43, AKR1C1, and AKR1C3 in MCF-7 cells. AKR1C3 has been reported to impact in intra-tumoral production of androgens and estrogens and thus, might promote Tamoxifen resistance in breast cancer. Over-expression of RORa1 and subsequently AKR1C3 does promote Tamoxifen resistance, which can be inhibited by melatonin administration.

Light is a potent biologic force that profoundly influences circadian, neuroendocrine, and neurobehavioral regulation in animals. Previously we examined the effects of light-phase exposure of rats to white light-emitting diodes (LED), which emit more light in the blue-appearing portion of the visible spectrum (465 to 485 nm) than do broad-spectrum cool white fluorescent (CWF) light, on the nighttime melatonin amplitude and circadian regulation of metabolism and physiology. In the current studies, we tested the hypothesis that exposure to blue-enriched LED light at day (bLAD), compared with CWF, promotes the circadian regulation of neuroendocrine, metabolic, and physiologic parameters that are associated with optimizing homeostatic regulation of health and wellbeing in 3 mouse strains commonly used in biomedical research (C3H [melatonin-producing], C57BL/6, and BALB/c [melatonin-non-producing]). Compared with male and female mice housed for 12 wk under 12:12-h light:dark (LD) cycles in CWF light, C3H mice in bLAD evinced 6-fold higher peak plasma melatonin levels at the middark phase; in addition, high melatonin levels were prolonged 2 to 3 h into the light phase. C57BL/6 and BALB/c strains did not produce nighttime pineal melatonin. Body growth rates; dietary and water intakes; circadian rhythms of arterial blood corticosterone, insulin, leptin, glucose, and lactic acid; pO2 and pCO2; fatty acids; and metabolic indicators (cAMP, DNA, tissue DNA 3H-thymidine incorporation, fat content) in major organ systems were significantly lower and activation of major metabolic signaling pathways (mTOR, GSK3β, and SIRT1) in skeletal muscle and liver were higher only in C3H mice in bLAD compared with CWF. These data show that exposure of C3H mice to bLAD compared with CWF has a marked positive effect on the circadian regulation of neuroendocrine, metabolic, and physiologic parameters associated with the promotion of animal health and wellbeing that may influence scientific outcomes. The absence of enhancement in amelatonic strains suggests hyperproduction of nighttime melatonin may be a key component of the physiology.

Over 248,000 men in the U.S. alone this year will be diagnosed with prostate cancer, and over 33,300 will die from the disease. The World Health Organization, in the case of breast cancer, has classified night-shift work involving light at night (LAN)-induced circadian disruption to be a probable carcinogen (Class 2A). Exposure to LAN suppresses nighttime pineal melatonin (MLT) production that influences normal and neoplastic tissue metabolism, physiology, and proliferation. Previously, we showed in rodent and human tumors in vivo that MLT inhibits linoleic acid (LA)-uptake and conversion to 13-hydroxyoctadecadienoic acid (13-HODE), a lipoxygenase product that enhances epidermal growth factor and insulin-like growth factor-I-induced mitogenesis. Recently, we developed a tissue-isolated, castration-sensitive VCaP human prostate cancer xenograft model to test the hypothesis that suppression of the nocturnal MLT signal due to exposure to dim LAN (dLAN) accelerates tumor LA-uptake and metabolism, aerobic glycolysis (Warburg Effect), and proliferative activity. Male nude rats (Crl:NIHFoxn1rnu; n=6/group) bearing castration-sensitive VCaP human prostate cancer xenografts were maintained on either a control L(300 lux)D(0 lux),12:12 or experimental LD,12:12dLAN (300 lux light phase followed by dLAN 0.2 lux dark phase intensity) light/dark cycle. Results revealed (Mean ± S.D.) plasma MLT levels in controls peaked in the mid-dark phase (183.4 ± 12.8 pg/mL) and were lowest (2.2 ± 0.4 pg/mL) in the mid-light phase, and low (< 10 pg/mL) throughout the 24-hr period in dLAN rats. Tumors in rats exposed to dLAN exhibited a significantly shorter latency to onset and a two-fold faster growth rate than controls. Harvested control group tumors revealed elevated cAMP levels, LA uptake, 13-HODE production, the Warburg effect, and [3H]thymidine incorporation into DNA, as well as elevated patterns of expression of signaling pathways phospho-ERK1/2, -AKT, -STAT3, -glycogen synthase kinase-3β (GSK3β), and -NF-κβ, and full-length androgen receptor and aldo-keto reductase (AKR1C3), during the light phase and markedly suppressed during the dark phase. In the dLAN group, these measures were markedly elevated throughout the 24-hr period. This is the first evidence in vivo, that dLAN-induced disruption of integrated circadian rhythms of signaling, metabolism, and proliferation results in accelerated growth of castration-sensitive human prostate cancer xenografts. Thus, lighting design strategies to minimize human exposure to LAN that preserve the integrity of the circadian MLT signal may offer a novel approach to suppress the growth progression of human castration-sensitive prostate cancer in our increasingly 24-hour society. Citation Format: Erin M. Dauchy, Robert T. Dauchy, Steven M. Hill, Yan Dong, Victoria P. Belancio, Shulin Xiang, George C. Brainard, John P. Hanifin, David E. Blask. Exposure to dim light at night disrupts the nocturnal melatonin signal in male nude rats bearing tissue-isolated castration-sensitive VCaP human prostate cancer: Impact on tumor circadian dynamics of the Warburg effect, lipid signaling and proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 222.

Background Feeding intolerance in patients with sepsis is associated with a lower enteral nutrition (EN) intake and worse clinical outcomes. The aim of this study was to develop and validate a predictive model for enteral feeding intolerance in the intensive care unit patients with sepsis. Methods In this dual-center, retrospective, case-control study, a total of 195 intensive care unit patients with sepsis were enrolled from June 2018 to June 2020. Data of 124 patients for 27 clinical indicators from one hospital were used to train the model, and data from 71 patients from another hospital were used to assess the external predictive performance. The predictive models included logistic regression, naive Bayesian, random forest, gradient boosting tree, and deep learning (multilayer artificial neural network) models. Results Eighty-six (44.1%) patients were diagnosed with enteral feeding intolerance. The deep learning model achieved the best performance, with areas under the receiver operating characteristic curve of 0.82 (95% confidence interval = 0.74-0.90) and 0.79 (95% confidence interval = 0.68-0.89) in the training and external sets, respectively. The deep learning model showed good calibration; based on the decision curve analysis, the model's clinical benefit was considered useful. Lower respiratory tract infection was the most important contributing factor, followed by peptide EN and shock. Conclusions The new prediction model based on deep learning can effectively predict enteral feeding intolerance in intensive care unit patients with sepsis. Simple clinical information such as infection site, nutrient type, and septic shock can be useful in stratifying a septic patient's risk of EN intolerance.

This study investigates the precipitation behavior in the graphene nanoplatelets (GNPs) reinforced bimodal structural Mg-6Zn (wt%) matrix composite. The GNPs with an increasing content progressively accelerate the age-hardening response in the local regions of the composite. The composite takes only half the time that the Mg-6Zn alloy needs to reach the peak strength when aging at 200 °C. The observation reveals that the planar and wrinkled GNPs in the composite act as the effective trigger of dislocations and collector of solute atoms to accelerate the precipitation. It is concluded that GNPs have a pronounced effect on the development of matrix microstructure. Moreover, the orientation relationship between the aligned GNPs towards the extrusion direction and the matrix grains with a fiber type texture makes the GNPs and [0001]Mg precipitate rods constitute a hybrid strengthening architecture in the composite. As a result, the synergistic strengthening effect of the GNPs and the precipitates is realized.

A1 adenosine receptor (AR) activation has been demonstrated to attenuate renal ischemia/reperfusion injury (IRI), but the exact mechanism of this protection remains to be well elucidated. Male C57BL/6 mice were used in the present study. Expression of heat shock protein (HSP) 27 and HSF-1 were detected using western blot analysis. An RNA interference with adenovirus vector using short hairpin RNA targeting HSP27 was developed. Together with renal IRI model, indicators of renal function, acute tubular necrosis, inflammation and apoptosis were measured in kidneys after 24-h reperfusion. We found activation of A1AR stimulated induction of HSP27 and its major transcriptional factor HSF-1. It was observed that renal inhibition of HSP27 abolished the renoprotective effects afforded by A1AR activation indicated by worse renal function, severer acute tubular necrosis and pro-inflammatory reaction. In addition, HSP27 induction by A1AR activation protects the kidney from IRI via suppressing cell apoptosis, proved by decreased caspase-3 activation and DNA fragmentation, which was also removed by inhibition of HSP27. Activation of A1AR produces renoprotective effects via HSP27 induction. It suggests that preconditional HSP27 activation might have a great potential for the treatment of renal IRI.

Near dense Mg 0.5 wt.% Zr (0, 1, 2.5 and 4) wt.% La alloys were successfully synthesized by disintegrated melt deposition technique followed by hot extrusion and were characterized for their microstructural, ignition, hardness, tensile and compression properties. Combined effects of Zr and La assisted in significant grain refinement of Mg and Mg 0.5 wt.% Zr 4 wt.% La exhibited an average grain size as low as ∼2.75 µm. High ignition temperature of ∼645 °C was realized with Mg 0.5 wt.% Zr (1, 2.5 and 4) wt.% La alloys. Microhardness value as high as ∼103 Hv was observed with Mg 0.5 wt.% Zr 4 wt.% La alloy. Under room temperature tensile and compression loading, significant improvements in the strength properties of pure Mg with the addition of 0.5 wt.% Zr (0, 1, 2.5 and 4) wt.% La was observed. Mg 0.5 wt.% Zr 4 wt.% La exhibited the maximum 0.2% tensile and compression yield strengths of ∼283 MPa and ∼264 MPa, respectively. The tensile and compression fracture strain values of synthesized pure Mg were found to be unaffected with the addition of 0.5 wt.% Zr. But the tensile fracture strain reduced with the addition of La while the compressive fracture strain was unaffected. Minimal tensile-compression asymmetry (∼1) was exhibited by Mg 0.5 wt.% Zr (1 and 2.5) wt.% La alloys.

EDTA dependent pseudothrombocytopenia (EDTA-PCTP) is a phenomenon that characterized by a spurious decrease of platelets in vitro due to the aggregation of platelets in EDTA anticoagulant blood samples. We report the first case of a transient appearance of EDTA-PCTP in a patient with 2019 novel coronavirus pneumonia (COVID-19). A 59-year-old woman was admitted to the isolated ward for severe type of 2019 novel coronavirus pneumonia. At the time of admission, her platelet count was in a normal range. Two days later, her platelet count decreased gradually without any signs or symptoms of bleeding. Since the peripheral blood smear showed a platelet aggregation, a blood sample anticoagulanted with citrate was tested and the number of platelet was normal. The phenomenon disappeared after 17 days when the patient was cured. This case emphasized the importance of peripheral blood smear and clinical manifestation, especially in the differential diagnosis of thrombocytopenia.

Breast cancer metastasis to bone is a major source of morbidity and mortality in women with advanced metastatic breast cancer. Morbidity from metastasis to bone is compounded by the fact that they cannot be surgically removed and can only be treated with chemotherapy and/or radiation therapy. Thus, there is critical need to develop new treatment strategies that kill bone metastatic tumors and reduce osteolytic lesions to improve patient quality of life and extend patient survival. Circadian rhythms are daily cycles of ~24 h that control many if not most physiologic processes and their disruption by exposure to light at night (LAN) or jet lag has been shown to be strongly associated with the development of cancer, particularly breast cancer. We have found that disruption of the anti-cancer circadian hormone melatonin (MLT) by light at night can significantly enhance the metastatic potential in breast cancer cells. Our work supports the report of the International Agency for Research on Cancer that shift work is a “probable human carcinogen” and highlights the association between exposure to light at night and invasive breast cancer. We recently reported that human breast tumor xenografts grown in athymic nude female rats housed in a photoperiod of 12h light at day: 12h dim light at night (dLAN, 0.2 lux - blocks the nighttime circadian MLT signal), display resistance to doxorubicin (Dox). More importantly, tumor growth and drug resistance could be blocked by the administration of Dox in circadian alignment with nocturnal MLT during dLAN. Our recent preliminary studies show that poorly invasive ERα positive MCF-7 breast cancer cells, when injected into the tibia (to mimic bone metastatic disease) of Foxn1nu athymic nude mice (which produce a strong circadian nighttime melatonin signal) housed in a dLAN photoperiod (suppressed nocturnal MLT production) developed full blown breast cancer tumors in bone (P

Disruption of circadian time structure and suppression of circadian nocturnal melatonin (MLT) production by exposure to dim light at night (dLAN), as occurs with night shift work and/or disturbed sleep-wake cycles, is associated with a significantly increased risk of breast cancer and resistance to tamoxifen and doxorubicin. Melatonin inhibition of human breast cancer chemo-resistance involves mechanisms including suppression of tumor metabolism and inhibition of kinases and transcription factors which are often activated in drug-resistant breast cancer. Signal Transducer and Activator of Transcription 3 (STAT3), frequently overexpressed and activated in Paclitaxel (PTX)-resistant breast cancer, promotes the expression of DNA methyltransferase one (DNMT1) to epigenetically suppresses the transcription of tumor suppressor Aplasia Ras homolog one (ARHI) which can sequester STAT3 in the cytoplasm to block PTX-resistance. We demonstrate that breast tumor xenografts in rats exposed to dLAN and circadian MLT disrupted express elevated levels of phosphorylated and acetylated STAT3, increased DNMT1, but reduced Sirtuin 1 (SIRT1) and ARHI. Furthermore, MLT and/or SIRT1 administration blocked/reversed Interleukin 6 (IL-6)-induced acetylation of STAT3 and its methylation of ARH1 to increase ARH1 mRNA expression in MCF-7 breast cancer cells. Finally, analyses of the I-SPY 1 trial demonstrates that elevated MT(1) receptor expression is significantly correlated with pathologic complete response following neo-adjuvant therapy in breast cancer patients. This is the first study to demonstrate circadian disruption of MLT by dLAN driving intrinsic resistance to PTX via epigenetic mechanisms increasing STAT3 expression and that MLT administration can reestablish sensitivity of breast tumors to PTX and drive tumor regression.

Liver cancer is the second leading cause of cancer death worldwide. Metabolic pathways within the liver and liver cancers are highly regulated by the central circadian clock in the suprachiasmatic nuclei (SCN). Daily light and dark cycles regulate the SCN-driven pineal production of the circadian anticancer hormone melatonin and temporally coordinate circadian rhythms of metabolism and physiology in mammals. In previous studies, we demonstrated that melatonin suppresses linoleic acid metabolism and the Warburg effect (aerobic glycolysis)in human breast cancer xenografts and that blue-enriched light (465-485 nm) from light-emitting diode lighting at daytime (bLAD) amplifies nighttime circadian melatonin levels in rats by 7-fold over cool white fluorescent (CWF) lighting. Here we tested the hypothesis that daytime exposure of tissue-isolated Morris hepatoma 7288CTC-bearing male rats to bLAD amplifies the nighttime melatonin signal to enhance the inhibition of tumor growth. Compared with rats housed under a 12:12-h light:dark cycle in CWF light, rats in bLAD light evinced a 7-fold higher peak plasma melatonin level at the mid-dark phase; in addition, high melatonin levels were prolonged until 4 h into the light phase. After implantation of tissue-isolated hepatoma 7288CTC xenografts, tumor growth rates were markedly delayed, and tumor cAMP levels, LA metabolism, the Warburg effect, and growth signaling activities were decreased in rats in bLAD compared with CWF daytime lighting. These data show that the increased nighttime circadian melatonin levels due to bLAD exposure decreases hepatoma metabolic, signaling, and proliferative activities beyond what occurs after normal melatonin signaling under CWF light.

Chemotherapeutic resistance, particularly to doxorubicin (Dox), represents a major impediment to successfully treating breast cancer and is linked to elevated tumor metabolism and tumor over-expression and/or activation of various families of receptor- and non-receptor-associated tyrosine kinases. Disruption of circadian time structure and suppression of nocturnal melatonin production by dim light exposure at night (dLEN), as occurs with shift work, and/or disturbed sleep-wake cycles, is associated with a significantly increased risk of an array of diseases, including breast cancer. Melatonin inhibits human breast cancer growth via mechanisms that include the suppression of tumor metabolism and inhibition of expression or phospho-activation of the receptor kinases AKT and ERK1/2 and various other kinases and transcription factors. We demonstrate in tissue-isolated estrogen receptor alpha-positive (ERα+) MCF-7 human breast cancer xenografts, grown in nude rats maintained on a light/dark cycle of LD 12:12 in which dLEN is present during the dark phase (suppressed endogenous nocturnal melatonin), a significant shortening of tumor latency-to-onset, increased tumor metabolism and growth, and complete intrinsic resistance to Dox therapy. Conversely, a LD 12:12 dLEN environment incorporating nocturnal melatonin replacement resulted in significantly lengthened tumor latency-to-onset, tumor regression, suppression of nighttime tumor metabolism, and kinase and transcription factor phosphorylation, while Dox sensitivity was completely restored. Melatonin acts as both a tumor metabolic inhibitor and circadian-regulated kinase inhibitor to reestablish the sensitivity of breast tumors to Dox and drive tumor regression, indicating that dLEN-induced circadian disruption of nocturnal melatonin production contributes to a complete loss of tumor sensitivity to Dox chemotherapy.

The present review discusses recent work on melatonin-mediated circadian regulation, the metabolic and molecular signaling mechanisms that are involved in human breast cancer growth, and the associated consequences of circadian disruption by exposure to light at night (LEN). The anti-cancer actions of the circadian melatonin signal in human breast cancer cell lines and xenografts heavily involve MT1receptor-mediated mechanisms. In estrogen receptor alpha (ERα)-positive human breast cancer, melatonin suppresses ERα mRNA expression and ERα transcriptional activity via the MT1receptor. Melatonin also regulates the transactivation of other members of the nuclear receptor superfamily, estrogen-metabolizing enzymes, and the expression of core clock and clock-related genes. Furthermore, melatonin also suppresses tumor aerobic metabolism (the Warburg effect) and, subsequently, cell-signaling pathways critical to cell proliferation, cell survival, metastasis, and drug resistance. Melatonin demonstrates both cytostatic and cytotoxic activity in breast cancer cells that appears to be cell type-specific. Melatonin also possesses anti-invasive/anti-metastatic actions that involve multiple pathways, including inhibition of p38 MAPK and repression of epithelial–mesenchymal transition (EMT). Studies have demonstrated that melatonin promotes genomic stability by inhibiting the expression of LINE-1 retrotransposons. Finally, research in animal and human models has indicated that LEN-induced disruption of the circadian nocturnal melatonin signal promotes the growth, metabolism, and signaling of human breast cancer and drives breast tumors to endocrine and chemotherapeutic resistance. These data provide the strongest understanding and support of the mechanisms that underpin the epidemiologic demonstration of elevated breast cancer risk in night-shift workers and other individuals who are increasingly exposed to LEN.

Background. LBP and fractalkine are known to be involved in the pathogenesis of ARDS. This study investigated the relationship between LBP and fractalkine in LPS-induced A549 cells and rat lung tissue in an ARDS rat model. Methods. A549 cells were transfected with LBP or LBP shRNA plasmid DNA or pretreated with SB203580 or SC-514 following LPS treatment. An ARDS rat model was established using LPS with or without LBPK95A, SB203580, or SC-514 treatment. RT-PCR, western blotting, ELISA, immunofluorescence, coimmunoprecipitation, and immunohistochemical staining were used to study the expression of fractalkine and LBP and p38 MAPK and p65 NF-κB activities. Results. LPS increased LBP and reduced fractalkine. LBP overexpression further decreased LPS-induced downregulation of fractalkine and p38 MAPK and p65 NF-κB activation; LBP gene silencing, SB203580, and SC-514 suppressed LPS-induced downregulation of fractalkine and p38 MAPK and p65 NF-κB activation in A549 cells. LBP and fractalkine in lung tissue were increased and decreased, respectively, following LPS injection. LBPK95A, SB203580, and SC-514 ameliorated LPS-induced rat lung injury and suppressed LPS-induced downregulation of fractalkine by decreasing phospho-p38 MAPK and p65 NF-κB. Conclusions. The results indicate that LBP downregulates fractalkine expression in LPS-induced A549 cells and in an ARDS rat model through activation of p38 MAPK and NF-κB.

Carbon nanotubes (CNTs) reinforced magnesium matrix composite prepared by an improved process was extruded at 350 °C with an extrusion ratio of 20:1. Most CNTs were individually and uniformly dispersed in the as-cast and the as-extruded composites. Moreover, good interfacial bonding was achieved, and Raman spectroscopy showed that the damage to CNTs was insignificant. The addition of CNTs could weaken basal plane texture. Meanwhile, the CNTs evidently improved the ultimate tensile strength, yield strength and Young’s modulus of the as-extruded composite. Pulling-out CNTs proved that the length of the CNTs was not large enough to be compatible with the high strength of the CNTs. Grain refinement, load transfer mechanism and Orowan strengthening mechanism play important roles on the increase of the yield strength. The composites fabricated by our process showed high strengthening efficiency of CNTs.

Melatonin has been shown repeatedly to inhibit the growth of human breast tumor cells in vitro and in vivo. Its antiproliferative effects have been well studied in MCF-7 human breast cancer cells and several other estrogen receptor α (ERα)-positive human breast cancer cell lines. However, the MDA-MB-231 breast cancer cell line, an ERα-negative cell line widely used in breast cancer research, has been shown to be unresponsive to melatonin's growth-suppressive effect in vitro. Here, we examined the effect of melatonin on the cell proliferation of several ERα-negative breast cancer cell lines including MDA-MB-231, BT-20, and SK-BR-3 cells. Although the MT1 G-protein-coupled receptor is expressed in all three cell lines, melatonin significantly suppressed the proliferation of SK-BR-3 cells without having any significant effect on the growth of MDA-MB-231 and BT-20 cells. We confirmed that the MT1-associated Gα proteins are expressed in MDA-MB-231 cells. Further studies demonstrated that the melatonin unresponsiveness in MDA-MB-231 cells may be caused by aberrant signaling downstream of the Gαi proteins, resulting in differential regulation of ERK1/2 activity.

In this work, graphene nanoplatelets (GNPs) reinforced magnesium (Mg) matrix composites were synthesised using the multi-step dispersion route. Well-dispersed but inhomogeneously distributed GNPs were obtained in the matrix. Compared with the monolithic alloy, the nanocomposites exhibited dramatically enhanced Young’s modulus, yield strength and ultimate tensile strength and relatively high plasticity, which mainly attributed to the significant heterogeneous laminated microstructure induced by the addition of GNPs. With increasing of the concentration of GNPs, mechanical properties of the composites were gradually improved. Especially, the strengthening efficiency of all the composites exceeded 100%, which was significantly higher than that of carbon nanotubes reinforced Mg matrix composites. The grain refinement and load transfer provided by the two-dimensional and wrinkled surface structure of GNPs were the dominated strengthening mechanisms of the composites. This investigation develops a new method for incorporating GNPs in metals for fabricating high-performance composites.

The phase equilibria in the Cu–Ni–Si ternary system have been investigated experimentally by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis on equilibrated ternary alloys. Three isothermal sections at 1073, 1173 and 1273 K are determined in the whole composition range. The existence of liquid phase and the ternary compound τ1 is confirmed at 1073 K. The binary γ (Cu5Si), γ (Ni31Si12), δ (Ni2Si) and θ (Ni2Si) phases exhibit a considerable solubility of a third element. In addition, the γ (Cu5Si) and θ (Ni2Si) phases can be stabilized by the addition of Ni and Cu, respectively.

Background Endothelin-1 (ET-1) is involved in pulmonary vascular remodeling. The aim of this study was to investigate the biochemical interactions between PPAR-γ, TGF-β1 and ET-1 in vitro. Methods A549 cells were pre-treated with S2505 (10 μM), S2871 (10 μM) with/without SB203580 (10 μM) for 60 min following 2 h treatment with 10 ng/mL TGF-β1. A549 cells were also transfected with positive or negative PPAR-γ plasmids for comparison. RT-PCR, ELISA, western blotting and confocal laser scanning microscopy (CLSM) were used to measure the relevant expression of mRNA, protein, mediators of pathways and nuclear factor translocation. Results SB203580 inhibited TGF-β1 induced ET-1 expression in A549 cells. S2871 decreased PPAR-γ mRNA and increase TGF-β1-induced ET-1 expression. S2871 increased phosphorylation of p38 MAPK and Smad2. Cells transfected with PPAR-γ negative plasmid increased TGF-β1 induced ET-1 expression, and increased the expression of phospho-p38 MAPK and phospho-Smad2. S2505 increased PPAR-γ mRNA expression, suppressed the increased TGF-β1-induced expression of ET-1. S2505 inhibited TGF-β1 induced phosphorylation of p38 MAPK and Smad2, also the nuclear translocation of Smad2. Cells transfected with PPAR-γ positive plasmid reduced TGF-β1-induced ET-1 expression, and inhibited the expression of phospho-p38 MAPK and phospho-Smad2. Conclusions TGF-β1 induced release of endothelin-1 is PPAR-γ dependent in cultured A549 cells.

Acute respiratory distress syndrome (ARDS) is characterized by inflammatory injury to the alveolar and capillary barriers that results in impaired gas exchange and severe acute respiratory failure. Nuclear orphan receptor Nur77 has emerged as a regulator of gene expression in inflammation, and its role in the pathogenesis of ARDS is not clear. The objective of this study is to investigate the potential role of Nur77 and its underlying mechanism in the regulation of endothelin-1 (ET-1) expression in lipopolysaccharide (LPS)-induced A549 cells and an ARDS rat model. We demonstrate that LPS induced Nur77 expression and nuclear export in A549 cells. Overexpression of Nur77 markedly decreased basal and LPS-induced ET-1 expression in A549 cells, whereas knockdown of Nur77 increased the ET-1 expression. LPS-induced phosphorylation and nuclear translocation of NF-κB and p38 MAPK were blocked by Nur77 overexpression and augmented by Nur77 knockdown in A549 cells. In vivo, LPS induced Nur77 expression in lung in ARDS rats. Pharmacological activation of Nur77 by cytosporone B (CsnB) inhibited ET-1 expression in ARDS rats, decreased LPS-induced phosphorylation of NF-κB and p38 MAPK, and relieved lung, liver, and kidney injury. Pharmacological deactivation of Nur77 by 1,1-bis-(3′-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH, C-DIM8) had no effect on ET-1 expression and lung injury. These results indicated that Nur77 decreases ET-1 expression by suppressing NF-κB and p38 MAPK in LPS-stimulated A549 cells in vitro, and, in an LPS-induced ARDS rat model, CsnB reduced ET-1 expression and lung injury in ARDS rats.

This study investigates differences in expression of clock and clock-controlled genes (CCGs) between human breast epithelial and breast cancer cells and breast tumor xenografts in circadian intact rats and examines if the pineal hormone melatonin influences clock gene and CCG expression. Oscillation of clock gene expression was not observed under standard growth conditions in vitro, however, serum shock (50% horse serum for 2 h) induced oscillation of clock gene and CCG expression in MCF-10A cells, which was repressed or disrupted in MCF-7 cells. Melatonin administration following serum shock differentially suppressed or induced clock gene (Bmal1 and Per2) and CCG expression in MCF10A and MCF-7 cells. These studies demonstrate the lack of rhythmic expression of clock genes and CCGs of cells in vitro and that transplantation of breast cancer cells as xenografts into circadian competent hosts re-establishes a circadian rhythm in the peripheral clock genes of tumor cells.

To determine if melatonin, via its MT1 G protein-coupled receptor (GPCR), impacts mouse mammary gland development, we generated a mouse mammary tumor virus (MMTV)-MT1-Flag-mammary gland over-expressing (MT1-mOE) transgenic mouse. Increased expression of the MT1-Flag transgene was observed in the mammary glands of pubescent MT1-mOE transgenic female mice, with further significant increases during pregnancy and lactation. Mammary gland whole mounts from MT1-mOE mice showed significant reductions in ductal growth, ductal branching, and terminal end bud (TEB) formation. Elevated MT1 receptor expression in pregnant and lactating female MT1-mOE mice was associated with reduced lobulo-alveolar development, inhibition of mammary epithelial cell proliferation, and significant reductions in body weights of suckling pups. Elevated MT1 expression in pregnant and lactating MT1-mOE mice correlated with reduced mammary gland expression of Akt1, phospho-Stat5, Wnt4, estrogen receptor alpha (ERα), progesterone receptors (PR) A and B, and milk proteins β-casein and whey acidic protein (WAP). Estrogen and progesterone stimulated mammary gland development was repressed by elevated MT1 receptor expression and exogenous melatonin administration. These studies demonstrate that the MT1 melatonin receptor and its ligand melatonin play an important regulatory role in mammary gland development and lactation in mice through both growth suppression and alteration of developmental paradigms.

This review article discusses recent work on the melatonin-mediated circadian regulation and integration of molecular, dietary, and metabolic signaling mechanisms involved in human breast cancer growth and the consequences of circadian disruption by exposure to light at night (LAN). The antiproliferative effects of the circadian melatonin signal are mediated through a major mechanism involving the activation of MT(1) melatonin receptors expressed in human breast cancer cell lines and xenografts. In estrogen receptor (ERα+) human breast cancer cells, melatonin suppresses both ERα mRNA expression and estrogen-induced transcriptional activity of the ERα via MT(1) -induced activation of G(αi2) signaling and reduction of 3',5'-cyclic adenosine monophosphate (cAMP) levels. Melatonin also regulates the transactivation of additional members of the steroid hormone/nuclear receptor super-family, enzymes involved in estrogen metabolism, expression/activation of telomerase, and the expression of core clock and clock-related genes. The anti-invasive/anti-metastatic actions of melatonin involve the blockade of p38 phosphorylation and the expression of matrix metalloproteinases. Melatonin also inhibits the growth of human breast cancer xenografts via another critical pathway involving MT(1) -mediated suppression of cAMP leading to blockade of linoleic acid uptake and its metabolism to the mitogenic signaling molecule 13-hydroxyoctadecadienoic acid (13-HODE). Down-regulation of 13-HODE reduces the activation of growth factor pathways supporting cell proliferation and survival. Experimental evidence in rats and humans indicating that LAN-induced circadian disruption of the nocturnal melatonin signal activates human breast cancer growth, metabolism, and signaling provides the strongest mechanistic support, thus far, for population and ecological studies demonstrating elevated breast cancer risk in night shift workers and other individuals increasingly exposed to LAN.

Luciferase reporter constructs and transient co-transfection approaches demonstrate that elevated expression of RORalpha1 augments 17-beta-estradiol (E(2))-induced transcriptional activation of the full-length ERalpha, but not truncated ERalpha constructs (ABCD or CDEF), in MCF-7 breast cancer and HEK293 embryonic kidney cells, and that physiologic concentrations of MLT inhibit the individual and combined transcriptional activity of ERalpha by RORalpha1 and E(2). Gel mobility shift and co-immunoprecipitation (IP)/pull-down assays demonstrate that RORalpha1 and ERalpha do not interact directly at the DNA-binding level or as heterodimers, however, RORalpha1 augments E(2)-induced pS2 and cyclin D1 mRNA expression while MLT inhibits RORalpha1/E(2)-induced expression of pS2 and cyclin D1 in MCF-7 cells.

The authors have shown that, via activation of its MT1 receptor, melatonin modulates the transcriptional activity of various nuclear receptors and the proliferation of both ERα+ and ERα- human breast cancer cells. Employing dominant-negative (DN) and dominant-positive (DP) G proteins, it was demonstrated that Gα i2 proteins mediate the suppression of estrogen-induced ERα transcriptional activity by melatonin, whereas the Gαq proteins mediate the enhancement of retinoid-induced RARα transcriptional activity by melatonin. In primary human breast tumors, the authors’ studies demonstrate an inverse correlation between ERα and MT1 receptor expression, and confocal microscopic studies demonstrate that the MT1I receptor is localized to the caveoli and that its expression can be repressed by estrogen and melatonin. Melatonin, via activation of its MT1 receptor, suppresses the development and growth of breast cancer by regulation of growth factors, regulation of gene expression, regulation of clock genes, inhibition of tumor cell invasion and metastasis, and even regulation of mammary gland development. The authors have previously reported that the clock gene, Period 2 ( Per2), is not expressed in human breast cancer cells but that its reexpression in breast cancer cells results in increased expression of p53 and induction of apoptosis. The authors demonstrate that melatonin, via repression of RORα transcriptional activity, blocks the expression of the clock gene BMAL1 . Melatonin’s blockade of BMAL1 expression is associated with the decreased expression of SIRT1, a member of the Silencing Information Regulator family and a histone and protein deacetylase that inhibits the expression of DNA repair enzymes (p53, BRCA1 & 2, and Ku70) and the expression of apoptosis-associated genes. Finally, the authors developed an MMTV-MT1-flag mammary knock-in transgenic mouse that displays reduced ductal branching, ductal epithelium proliferation, and reduced terminal end bud formation during puberty and pregnancy. Lactating female MT1 transgenic mice show a dramatic reduction in the expression of β-casein and whey acidic milk proteins. Further analyses showed significantly reduced ERα expression in mammary glands of MT1 transgenic mice. These results demonstrate that the MT1 receptor is a major transducer of melatonin’s actions in the breast, suppressing mammary gland development and mediating the anticancer actions of melatonin through multiple pathways.

Leiomyosarcoma (LMS) represents a highly malignant, rare soft tissue sarcoma with high rates of morbidity and mortality. Previously, we demonstrated that tissue-isolated human LMS xenografts perfused in situ are highly sensitive to the direct anticancer effects of physiological nocturnal blood levels of melatonin which inhibited tumour cell proliferative activity, linoleic acid (LA) uptake and metabolism to 13-hydroxyoctadecadienoic acid (13-HODE). Here, we show the effects of low pharmacological blood concentrations of melatonin following oral ingestion of a melatonin supplement by healthy adult human female subjects on tumour proliferative activity, aerobic glycolysis (Warburg effect) and LA metabolic signalling in tissue-isolated LMS xenografts perfused in situ with this blood. Melatonin markedly suppressed aerobic glycolysis and induced a complete inhibition of tumour LA uptake, 13-HODE release, as well as significant reductions in tumour cAMP levels, DNA content and [(3) H]-thymidine incorporation into DNA. Furthermore, melatonin completely suppressed the phospho-activation of ERK 1/2, AKT, GSK3β and NF-kB (p65). The addition of S20928, a nonselective melatonin antagonist, reversed these melatonin inhibitory effects. Moreover, in in vitro cell culture studies, physiological concentrations of melatonin repressed cell proliferation and cell invasion. These results demonstrate that nocturnal melatonin directly inhibited tumour growth and invasion of human LMS via suppression of the Warburg effect, LA uptake and other related signalling mechanisms. An understanding of these novel signalling pathway(s) and their association with aerobic glycolysis and LA metabolism in human LMS may lead to new circadian-based therapies for the prevention and treatment of LMS and potentially other mesenchymally derived solid tumours.

Over 36,000 people in the United States will be diagnosed with hepatocellular carcinoma (HCC) in 2016, the second leading cause of cancer death worldwide. Metabolic pathways within the liver and in HCC are highly regulated by the central circadian clock in the suprachiastmatic nucleus (SCN). The SCN drives nighttime production of the circadian anti-cancer hormone melatonin by the pineal gland in rats and humans. We have shown that the nighttime circadian melatonin signal suppresses the Warburg effect (aerobic glycolysis) in human breast cancer xenografts and that blue-enriched light (460-480 nm) from LEDs at daytime (bLAD), amplifies the nighttime circadian melatonin signal by 7-fold in rats over cool white fluorescent (CWF) lighting. Here we tested whether daytime exposure of tissue-isolated HepG2 xenograft-bearing male nude rats to bLAD amplifies the nighttime melatonin signal to increase tumor sensitivity to nighttime administered sorafenib (FDA-approved multi-kinase inhibitor) treatment via enhancing suppression of the Warburg effect. Animals were randomized to 6 subgroups (n = 4): CWF Groups I, 12 h light:12 h dark (LD,12:12) (CWF + vehicle) and II (CWF + sorafenib); bLAD Groups III (LD,12bLAD:12) (bLAD + vehicle), IV (bLAD + sorafenib), V (bLAD + S20928 MT1/MT2 receptor blocker), and VI (bLAD + S20928 + sorafenib). Drug treatments began when tumors were 2.5 g estimated weight. Plasma nighttime melatonin levels were 7-fold higher in Groups III-VI, compared to Groups I and II. Tumor latency-to-onset of growth and growth rates were markedly delayed and decreased, respectively, in Group III compared to Group I. Sorafenib induced tumor regression at a rate that was 2-fold higher in the bLAD- vs CWF-exposed rats. Tumor glucose uptake and lactate production (Warburg effect) at the mid-dark phase were significantly reduced in CWF-exposed rats receiving sorafenib vs vehicle. In vehicle-treated bLAD-exposed rats, the Warburg effect was significantly decreased vs CWF-exposed rats receiving vehicle. In bLAD + sorafenib-treated rats, the Warburg effect was reduced by an additional 51% (glucose uptake) and 89% (lactate production), respectively, vs CWF + sorafenib-treated rats. Melatonin receptor blocker S20928 completely prevented the effects of bLAD and bLAD + sorafenib on the Warburg effect and made these tumors completely resistant to sorafenib-induced tumor regression. These findings are the first to show in vivo that: 1) nighttime circadian sorafenib therapy inhibited the Warburg effect and induced HepG2 tumor regression under CWF lighting conditions, and 2) the bLAD-amplified nocturnal circadian melatonin signal increased tumor sensitivity to sorafenib-induced regression by enhancing a melatonin receptor-mediated suppression of the Warburg effect. Citation Format: Robert T. Dauchy, David T. Pointer, Aaron E. Hoffman, Melissa A. Wren-Dail, Shulin Xiang, Lin Yuan, David E. Blask, Victoria P. Belancio, Steven M. Hill. Daytime blue-enriched LED light-induced circadian amplification of the nighttime melatonin signal increases sorafenib sensitivity in human hepatocellular carcinoma via enhanced suppression of the Warburg effect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3191. doi:10.1158/1538-7445.AM2017-3191

Cancer patients with disrupted 24-hour (circadian) rhythms are reported to have poorer survival as compared to those with normal rhythms. Severe alterations in circadian rhythms predict an increased risk of death in patients with colorectal and breast cancer, suggesting that circadian disruption may impact tumor progression and metastasis. We recently reported that circadian/melatonin (MLT) disruption by exposure to dim light at night (dLAN) resulted in constitutive phospho-activation of ERK1/2, CREB, NF-kB, and STAT3 in breast tumor xenografts promoting resistance to Tamoxifen and Doxorubicin therapy. Given that chemoresistant breast cancer is frequently metastatic, this study examined if dLAN-induced circadian/MLT disruption can promote epithelial-to- mesenchymal transition (EMT) of epithelial MCF-7 breast tumor xenografts leading to the development of metastatic foci in the lungs, livers, and brains of circadian complete (MLT-producing) athymic nude female rats and mice. Female nude rats with ERα+ MCF-7 or T47D human epithelial breast cancer xenografts were housed in LD,12:12 and LD,12:12dLAN (dLAN) photoperiods or in dLAN supplemented with nighttime MLT (0.05 µg/ml) in the drinking water, with lights on at 0600 hrs and off at 1800 hrs. Blood samples collected during the mid-dark phase (2400 hrs) showed elevated nocturnal melatonin (118.4 pg/ml) in the LD,12:12 group, but significantly suppressed melatonin (10.0 pg/ml) in the dLAN group. Tumor xenografts from rats housed in dLAN showed a ~3-fold decrease in latency-to-onset and a ~2.8-fold increase in growth rates vs. those from rats in dLAN + MLT. Tumor cAMP levels, as well as numerous signaling pathways involved in promoting EMT (Vimentin, β-catenin, and SNAIL) and metastasis (HER2/HER3, pCREB, pERK1/2, pRSK2, and pSTAT3), showed increased expression/phospho-activation at 2400 hrs in response to dLAN but repressed expression in tumors from rats in dLAN + MLT. Follow-up studies with Foxn1nude female mice implanted with non-metastatic luciferase expressing MCF-7 breast cancer cells showed that exposure to dLAN suppressed the nighttime serum levels of MLT by 93% in these mice compared to those in a LD,12:12 photoperiod. Exposure of mice to dLAN induced the rapid growth of MCF-7luc tumor xenografts and, after 5 weeks, induced the metastatic outgrowth of MCF-7 xenografts to form luciferase identifiable metastatic foci in the lungs, livers, and brains of all mice, as measured by IVIS small animal imaging system. Conversely, MCF-7luc tumor xenografts from mice exposed to dLAN and supplemented with nighttime MLT showed a reduced tumor development, 3-fold slower tumor growth, and a small metastatic lesion in one lung of a single mouse. This study is the first to show that circadian/MLT disruption by host exposure to dLAN is able to drive EMT in human epithelial breast cancer xenografts to generate metastatic foci in lung, liver, and brain of mice. Citation Format: Steven M. Hill, Shulin Xiang, Robert T. Dauchy, Melissa Wren-Dail, Murali Anbalagan, Brian Rowan, Tripp Frasch, David E. Blask. Circadian/melatonin disruption by dim light at night drives human epithelial breast cancer to a metastatic phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4897. doi:10.1158/1538-7445.AM2017-4897

Germinal center-B (GC-B) cells differentiate into memory B cells and plasma cells (PC) through interaction with T cells and follicular dendritic cells (FDC). Activated T cell and FDC play distinct roles in this process. The detailed kinetic experiments revealed that cytokines secreted by activated T cells determined the pathway of GC-B cell differentiation. IL-4 directs GC-B cells to differentiate into memory B cells, whereas IL-10 steers them into PC. FDC/HK cells do not direct either pathway, but provide signals for proliferation of GC-B cells. A novel FDC-signaling molecule 8D6 (FDC-SM-8D6) produced by FDC augments PC generation in the GC. FDC-SM-8D6-specific mAb blocked PC generation and IgG secretion but not memory B cell proliferation. COS cells expressing FDC-SM-8D6 enhanced GC-B cell proliferation and Ab secretion, which was blocked by mAb 8D6. In the cultures with B cell subsets, PC generation was inhibited by mAb 8D6 in the cultures with CD27+ B cells but not in the culture with CD27− B cells, suggesting that CD27+ PC precursor is the specific target of FDC-SM-8D6 stimulation.

Melatonin, has been shown repeatedly to inhibit the growth of human breast tumor cells in vitro and in vivo. Its anti-proliferative effects have been well-studied in MCF-7 human breast cancer cells and several other estrogen receptor α (ERα)-positive human breast cancer cell lines. However, the MDA-MB-231 breast cancer cell line, an ERα negative cell line widely used in breast cancer research, has been shown to be unresponsive to melatonin’s growth-suppressive effect in vitro. Here we examined the effect of melatonin on the cell proliferation of several ERα-negative breast cancer cell lines including MDA-MB-231, BT-20 and SK-BR-3 cells. Although the MT1 G-protein-coupled receptor is expressed in all three cell lines, melatonin significantly suppressed the proliferation of SK-BR-3 cells without having any significant effect on the growth of MDA-MB-231 and BT-20 cells. We confirmed that the MT1-associated Gα proteins are expressed in MDA-MB-231 cells. Further studies demonstrated that the melatonin-unresponsiveness in MDA-MB-231 cells may be caused by aberrant signaling downstream of the Gαi proteins, resulting in differential regulation of ERK1/2 activity.

Resistance to chemotherapy is a significant impediment to the treatment of breast cancer. More than 30% of breast cancer patients present with intrinsic resistance to chemotherapy; almost all who initially respond will develop acquired resistance. Resistant tumors frequently exhibit constitutive activation of numerous survival signaling pathways, including ERK, AKT, NF-kB, and STAT3. We have reported that the circadian hormone melatonin inhibits the growth of both ERá+/ERá- breast cancers and, as well as the daytime induced phospho-activation of ERK1/2, AKT and NF-kB in breast tumor xenografts. We also demonstrated that dim light at night (dLAN), by decreasing nocturnal melatonin, resulted in constitutive phospho-activation of ERK1/2, CREB, NF-kB, and STAT3, promoting resistance to tamoxifen and doxorubicin therapy. Here we tested the hypothesis that dLAN, via phospho-activation of ERK1/2 and STAT3, promotes resistance to paclitaxel (Pax). Female nude rats with “tissue-isolated” MCF-7 breast cancer xenografts were housed in photoperiodic conditions of either LD 12:12, 12:12dLAN (0.2 lux), or 12:12dLAN supplemented with nighttime melatonin (0.05 õg/ml) in the drinking water, with lights on at 0600 hrs and off at 1800 hrs. When estimated tumor weights reached 2.5 g, animals were treated daily with either diluent or Pax i.p. (4õã/kg) 2 h prior to onset of dLAN or dLAN with nighttime melatonin supplementation. Blood samples collected during the mid-dark phase (2400 hrs) showed elevated nocturnal melatonin in the LD 12:12 group, but significantly suppressed melatonin in the dLAN group. Tumor xenografts from rats housed in dLAN showed a 3-fold decrease in latency-to-onset and a 2.8-fold increased growth rates vs. those from rats receiving melatonin supplementation. Tumor cAMP levels, linoleic acid, and tumor metabolism (Warburg effect) were significantly elevated in dLAN tumors. Numerous signaling pathways including ERK1/2, RSK2, and STAT3, were phospho-activated and others including AKT and HER2/3 were elevated at 2400 hrs by dLAN but repressed in dLAN melatonin supplemented tumors. Tumors from dLAN rats showed intrinsic resistance to Pax, whereas those in LD 12:12 or dLAN and supplemented with nighttime melatonin rapidly regressed. These findings show that temporally coordinated and integrated metabolic and signal transduction mechanisms, particularly the STAT3 pathway, underlying human breast cancer growth, can be activated by the host's exposure to LAN with profound effects culminating in rapid tumor progression and the development of resistance to chemotherapy. Citation Format: Steven M. Hill, Shulin Xiang, Robert T. Dauchy, Lulu mao, Lin Yuan, Adam Hauch, Victoria P. Belancio, Melissa A. Wren-Dail, David Pointer, Peter W. Lundberg, Whitney M. Summers, David E. Blask. Circadian/melatonin disruption by dim light at night drives paclitaxel resistance in breast cancer via activation of stat3. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 874.

Current evidence indicates that rotating night shift workers have an increased risk of developing breast and prostate cancers, which have been associated with light at night (LAN)-induced circadian disruption as the principal risk factor. Previously, we demonstrated that animal room dark phase light contamination with as little as 0.20 lux (0.08 μW/cm2) suppressed the nocturnal production of the circadian oncostatic neurohormone melatonin and stimulated human breast tumor growth and metabolism. The circadian melatonin signal suppresses tumor growth and metabolism via an MT1 melatonin receptor-mediated signaling mechanism involving inhibition of aerobic glycolysis (Warburg effect) and linoleic acid (LA) uptake and conversion to the mitogen 13-hydroxyoctadecadienoic acid (13-HODE) culminating in down-regulation of the epidermal growth factor and insulin-like growth factor-1 pathways. We developed a new tissue-isolated androgen-receptor positive (AR+), castration-sensitive VCaP prostate tumor model in adult male athymic nude rats (Crl:NIH-Foxn1rnu), to test the hypothesis that nocturnal melatonin levels inhibit, while dim LAN (dLAN)-induced suppression of nocturnal melatonin production stimulates, tumor signaling, metabolic and growth activity. VCaP xenograft-bearing rats (n = 6/group) maintained on either a control light/dark cycle (LD, 12:12; 300 lux light phase intensity) or an experimental light/dark cycle (LD, 12:12dLAN (0.2 lux; dark phase intensity) for 6 weeks resulted in a 2.5-fold decrease in latency-to-onset (time of implant to first palpable mass) and 2-fold increase in tumor growth rates in experimental animals lacking a nocturnal circadian melatonin signal as compared to control animals with an intact melatonin signal. In control animals, plasma melatonin levels were high in the mid-dark phase (183.4 ± 12.8 pg/mL) and low (2.2 ± 0.4 pg/mL) in mid-light phase, while they were low throughout the 24-hr period in dLAN-exposed animals. Tumors harvested during the mid-dark phase (2400 h) revealed that cAMP levels, Warburg effect (increased glucose uptake and lactate production), LA uptake, 13-HODE production, and DNA [3H]Thymidine incorporation were all significantly elevated (P < 0.001) in dLAN as compared with the controls. Signaling pathways AKT, MEK, ERK ½, STAT3, GSK3ß, and NFκß were all phospho-activated along with increased expression of Aldo-keto reductase family 1 member C3 (AKR1C3) under dLAN conditions. AKR1C3 has been associated with intratumoral androgen synthesis and the development of castration-resistance. These findings are the first to show that the nocturnal melatonin signal inhibits, while dLAN stimulates the Warburg effect, LA metabolism and growth activity, signaling activity and AKR1C3 expression in VCaP human androgen-sensitive prostate cancer. Citation Format: Robert T. Dauchy, Melissa A. Wren, Erin M. Dauchy, Steven M. Hill, Lin Yuan, Shulin Xiang, Yan Dong, Victoria P. Belancio, David M. Blask. Light exposure at night influences host/cancer circadian regulatory dynamics, Warburg effect, and human prostate cancer progression in nude rats. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 36.

Disturbed sleep-wake cycle and circadian rhythmicity are associated with cancer, but the underlying mechanisms are unknown. Employing a tissue-isolated human breast xenograft tumor nude rat model, we observed that glycogen synthase kinase 3β (GSK3β), an enzyme critical in metabolism and cell proliferation/survival, exhibits a circadian rhythm of phosphorylation in human breast tumors. Exposure to light-at-night suppresses the nocturnal pineal melatonin synthesis, disrupting the circadian rhythm of GSK3β phosphorylation. Melatonin activates GSK3β by inhibiting the serine-threonine kinase Akt phosphorylation, inducing β-catenin degradation and inhibiting epithelial-to-mesenchymal transition, a fundamental process underlying cancer metastasis. Thus, chronic circadian disruption by light-at-night via occupational exposure or age-related sleep disturbances may contribute to cancer incidence and the metastatic spread of breast cancer by inhibiting GSK3β activity and driving epithelial-to-mesenchymal transition in breast cancer patients.