Nrf2-Keap1 pathway promotes cell proliferation and diminishes ferroptosis

Cancer cells are hallmarked by high proliferation and imbalanced redox consumption and signaling. Various oncogenic pathways such as proliferation and evading cell death converge on redox-dependent signaling processes. Nrf2 is a key regulator in these redox-dependent events and operates in cytoprotection, drug metabolism and malignant progression in cancer cells. Here, we show that patients with primary malignant brain tumors (glioblastomas, WHO °IV gliomas, GBM) have a devastating outcome and overall reduced survival when Nrf2 levels are upregulated. Nrf2 overexpression or Keap1 knockdown in glioma cells accelerate proliferation and oncogenic transformation. Further, activation of the Nrf2-Keap1 signaling upregulates xCT (aka SLC7A11 or system X_c⁻) and amplifies glutamate secretion thereby impacting on the tumor microenvironment. Moreover, both fostered Nrf2 expression and conversely Keap1 inhibition promote resistance to ferroptosis. Altogether, the Nrf2-Keap1 pathway operates as a switch for malignancy in gliomas promoting cell proliferation and resistance to cell death processes such as ferroptosis. Our data demonstrate that the Nrf2-Keap1 pathway is critical for cancer cell growth and operates on xCT. Nrf2 presents the Achilles’ heel of cancer cells and thus provides a valid therapeutic target for sensitizing cancer for chemotherapeutics.

CT coronary angiography findings in non-atherosclerotic coronary artery diseases

Non-atherosclerotic coronary artery diseases are being increasingly recognised as causes of acute coronary events. Invasive coronary angiography frequently fails to identify the abnormalities in the proximal course of coronary arteries and coronary wall, while computed tomography coronary angiography (CTCA) allows for acquisition of more detailed information. CTCA serves as a reliable method for evaluating patients with non-atherosclerotic coronary artery diseases. The purpose of this article is to provide an overview of non-atherosclerotic abnormalities that may be demonstrated on CTCA.

L-Tetrahydropalmatine Induces Apoptosis in EU-4 Leukemia Cells by Down-Regulating X-Linked Inhibitor of Apoptosis Protein and Increases the Sensitivity Towards Doxorubicin

BACKGROUND

L-Tetrahydropalmatine (L-THP) is a tetra-hydro protoberberine isoquinoline alkaloid. The phyto-compounds bearing isoquinoline alkaloids have been reported to show a potential effect against a number of human cancers cell lines including leukemia. We hypothesized that L-THP, being an isoquinoline alkaloid, could be a potential molecule against acute lymphoblastic leukemia (ALL), in this study, we evaluate L-THP against p53 deficient leukemia EU-4 cell lines in vitro.

METHODS

For the study, p53 null leukemia EU-4 cells were used and treated with LTHP. The extent of apoptosis and viability of cells were determined. Expression of apoptosis related proteins such as XIAP and MDM2 was done by western blot and PCR studies. The expression of MDM2 and XIAP was knocked down by small interfering RNA (siRNA).

RESULTS

Outcomes of the study suggested that L-THP caused p53-indipendent apoptosis mediated by XIAP in EU-4 cells. The treatment of L-THP caused a decrease in the levels of XIAP protein with increasing dose and time. L-THP caused down-regulation of XIAP protein via inhibiting the expression of MDM2 and involving proteasomedependent pathway. Also, the outcomes of experiments suggested increased sensitivity of leukemia cells towards doxorubicin due to the inhibition of XIAP by L-THP or by siRNA.

CONCLUSION

Findings of the study confirm that L-THP resulted in p53 independent apoptosis via down-regulating XIAP protein by inhibiting MDM2 associated with proteasome-dependent pathway and increased sensitivity of EU-4 cells against doxorubicin. L-THP caused activation of caspase and resulted in apoptosis, L-THP may be a novel molecule for inducing apoptosis specifically in p53 null leukemia EU-4 cells.

ATF4 promotes angiogenesis and neuronal cell death and confers ferroptosis in a xCT-dependent manner

Activating transcription factor 4 (ATF4) is a critical mediator of metabolic and oxidative homeostasis and cell survival. ATF4 is elevated in response to diverse microenvironmental stresses, including starvation, ER stress damages and exposure to toxic factors. Here we show that ATF4 expression fosters the malignancy of primary brain tumors (WHO grade III and IV gliomas) and increases proliferation and tumor angiogenesis. Hence, ATF4 expression promotes cell migration and anchorage-independent cell growth, whereas siRNA-mediated knockdown of ATF4 attenuates these features of malignancy in human gliomas. Further experiments revealed that ATF4-dependent tumor promoting effects are mediated by transcriptional targeting the glutamate antiporter xCT/SCL7A11 (also known as system Xc^-). Thus, xCT is elevated as a consequence of ATF4 activation. We further found evidence that ATF4-induced proliferation can be attenuated by pharmacological or genetic xCT inhibition and ferroptosis inducers such as sorafenib, erastin and GPx4 inhibitor RSL3. Further, fostered xCT expression promotes cell survival and growth in ATF4 knockdown cells. Moreover, increased xCT levels ameliorate sorafenib and erastin-induced ferroptosis. Conversely, ATF4 knockdown renders cells susceptible for erastin, sorafenib and RSL3-induced ferroptosis. We further identified that ATF4 promotes tumor-mediated neuronal cell death which can be alleviated by xCT inhibition. Moreover, elevated ATF4 expression in gliomas promotes tumor angiogenesis. Noteworthy, ATF4-induced angiogenesis could be diminished by ferroptosis inducers erastin and by GPx4 inhibitor RSL3. Our data provide proof-of-principle evidence that ATF4 fosters proliferation and induces a toxic microenvironmental niche. Furthermore, ATF4 increases tumor angiogenesis and shapes the vascular architecture in a xCT-dependent manner. Thus, inhibition of ATF4 is a valid target for diminishing tumor growth and vasculature via sensitizing tumor cells for ferroptosis.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

36 SERIAL SOMATIC CELL NUCLEAR TRANSFER INCREASES PREGNANCY LOSSES IN GOATS

Serial cloning by somatic cell nuclear transfer (SCNT) has been successful in several mammalian species. This method can be beneficial for transgenic line expansion or resetting the lifespan of transgenic cells. Previous studies in bovine and porcine have shown a decrease in efficiency over multiple iterations of serial cloning. However, the contradictory data has been reported in mice where no decrease in cloning efficiency was observed after 25 generations of recloning. To our knowledge, no data have been reported investigating the efficiency of serial cloning in goats. The aim of this study was to evaluate whether there is an effect of recloning on goat SCNT efficiency. αMHC-TGF-β1 fetal fibroblast cells (containing transforming growth factor-β under control of a cardiac-specific promoter) were produced by electroporation and used for the first round of SCNT. For serial cloning, we used neonatal fibroblast cells obtained from skin biopsies used as nuclear donors. These cells were collected from the transgenic cloned goats generated by the first round of SCNT. Cumulus-oocyte complexes recovered from abattoir-derived ovaries using slicing technique were matured in vitro for 20 to 24 h. The first polar body and metaphase plate were removed from a cumulus cell-free oocyte, and a donor fibroblast cell was subsequently transferred into the enucleated oocyte. Fused embryos were then activated for 5 min in 5 mM ionomycin followed by 4 h in 2 mM DMAP with 5 mg mL−1 cycloheximide. Activated embryos were cultured in G1 medium with 5 mg mL−1 BSA for 12 h, followed by surgical transfer into the oviducts of recipients synchronized to show oestrus within 12 h of SCNT. In total, 592 and 395 embryos were transferred to 37 and 25 recipient goats, respectively, for the first and second round of SCNT. Pregnancy rate, rate of pregnancy loss, and term rate were analysed by Chi-squared with a 2-tailed P-value. No significant difference was observed in Day 40 pregnancy rates (32.4 v. 36%) and term rates (32.4 v. 20%) between the first round of cloning and the successive recloning. However, the rate of pregnancy losses was significantly greater in recloning group (P < 0.05), with 4 out of 9 pregnancies lost between Day 40 of gestation and term, whereas no pregnancy losses were observed after Day 40 of gestation in the first-round cloning group. The greater pregnancy loss in the recloning procedure might be caused by accumulation of epigenetic errors resulting from incomplete reprogramming. We are assessing the DNA methylation pattern of differentially methylated regions (DMR) of 2 paternally imprinted genes (H19 and IGF2R) in the cloned and recloned goats and expect to see a difference in their imprinted gene DNA methylation pattern, which could explain the greater rate of pregnancy loss in recloned goats.

Wave mode extraction from multimodal wave signals in an orthotropic composite plate

In this paper the post-processing procedure based on the mode orthogonality is applied to extract individual waveforms at a composite plate edge from multimodal signals. To obtain the amplitudes of individual modes, numerically predicted modal through-thickness stress and displacement field values are used in the orthogonality relation. The performance of the mode extraction technique is evaluated by processing signals obtained from Finite Element (FE) modeling and experimental measurements. The propagation of the overlapping wave packets of Lamb modes S0 and A0 is considered along the fiber direction and perpendicular to that direction. The required experimental two-dimensional displacement components at the plate edge are measured by 3D Scanning Laser Doppler Vibrometer (3D SLDV). It is demonstrated that S0 mode can be extracted very well from the signal but A0 mode with slightly poorer accordance with the original waveforms and numerical predictions.

Non-traumatic hernia of the lateral abdominal wall in a patient infected with the human immunodeficiency virus

Introduction There are several classifications for abdominal hernias, and a non-traumatic lateral wall hernia (LAWH) is a rare type. We report the first case of a patient with LAWH infected with the human immunodeficiency virus (HIV). Case History A 53-year-old HIV-infected male presented with an abdominal mass. The patient had a history of treatment with combination antiretroviral therapy. A LAWH was diagnosed based on physical examination and findings of computed tomography. Open mesh repair was undertaken successfully. The patient had no evidence of a recurrent hernia during 11 months of follow-up. Conclusions High intra-abdominal pressure and weak connective tissue can lead to LAWHs. Antiretroviral therapy and lipodystrophy can cause LAWHs in HIV-infected patients.

Bone Fracture Enhances Trauma Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity in young individuals worldwide. However, the understanding of TBI at secondary phase remained obscure, and more knowledge of the pathophysiology of TBI is necessary. In this study, we examined the influence of bone fracture (BF) on TBI and investigated whether blocking high mobility group 1 (HMGB1) protein, an inflammatory mediator, could be effective to alleviate TBI. We found neurological severity was significantly increased by BF at 4 days post-TBI with longer removal time of adhesive tape and higher percentage of left turn in the corner test compared to TBI treatment alone. Additionally, higher brain lesion volume and severer brain oedema in TBI + BF mice supports the negative effect of BF on TBI. HMGB1 level was significantly stimulated by BF, suggesting the important role of HMGB1 in the development of secondary TBI. Notably, ablation of HMGB1 significantly reduced this negative influence of BF on TBI. These results suggest that HMGB1 can be massively induced by the systemic immune activation triggered by BF, which in turn aggravates inflammation. Blocking HMGB1 reduced the inflammatory effect of BF and therefore helps lessen the severity of secondary TBI. In conclusion, these results provided the evidence that anti-HMGB1 may be an effective and feasible method to alleviate TBI.