Mechanotransduction of mitochondrial AMPK and its distinct role in flow-induced breast cancer cell migration

The biophysical microenvironment of the tumor site has significant impact on breast cancer progression and metastasis. The importance of altered mechanotransduction in cancerous tissue has been documented, yet its role in the regulation of cellular metabolism and the potential link between cellular energy and cell migration remain poorly understood. In this study, we investigated the role of mechanotransduction in AMP-activated protein kinase (AMPK) activation in breast cancer cells in response to interstitial fluid flow (IFF). Additionally, we explored the involvement of AMPK in breast cancer cell migration. IFF was applied to the 3D cell-matrix construct. The subcellular signaling activity of Src, FAK, and AMPK was visualized in real-time using fluorescent resonance energy transfer (FRET). We observed that breast cancer cells (MDA-MB-231) are more sensitive to IFF than normal epithelial cells (MCF-10A). AMPK was activated at the mitochondria of MDA-MB-231 cells by IFF, but not in other subcellular compartments (i.e., cytosol, plasma membrane, and nucleus). The inhibition of FAK or Src abolished flow-induced AMPK activation in the mitochondria of MDA-MB-231 cells. We also observed that global AMPK activation reduced MDA-MB-231 cell migration. Interestingly, specific AMPK inhibition in the mitochondria reduced cell migration and blocked flow-induced cell migration. Our results suggest the linkage of FAK/Src and mitochondria-specific AMPK in mechanotransduction and the differential role of AMPK in breast cancer cell migration depending on its subcellular compartment-specific activation

Tourist shopping behavior : a case of Shanghai outbound tourists / Yingzhi Guo...[et al.]

Shopping is an important tourist activity and its contribution to the economy is significant. For many visitors no trip is complete without having spent time shopping and tourists often feel they cannot return home without buying “something”. This research explored the basic shopping behaviour model of Shanghai outbound tourists. Data from 65 respondents were collected using the convenient sampling method. The motivations of Shanghai outbound tourists’ shopping behaviour were presented in seven dimensions including function, gift giving, affection, curiosity, scarcity, memory and cultural orientations. Quality, brand, shortage of specific goods in China’s domestic market, the lower price of goods in the outbound market and the convenient payments in the destinations are important attributes that spark their shopping behaviours. This outcome has at least had significant implications for tour operators and marketers to understand the needs of Chinese outbound tourists

Genome-wide identification and characterization of ATP-binding cassette transporters in the silkworm, Bombyx mori

<p>Abstract</p> <p>Background</p> <p>The ATP-binding cassette (ABC) transporter superfamily is the largest transporter gene family responsible for transporting specific molecules across lipid membranes in all living organisms. In insects, ABC transporters not only have important functions in molecule transport, but also play roles in insecticide resistance, metabolism and development.</p> <p>Results</p> <p>From the genome of the silkworm, <it>Bombyx mori</it>, we have identified 51 putative ABC genes which are classified into eight subfamilies (A-H) by phylogenetic analysis. Gene duplication is very evident in the ABCC and ABCG subfamilies, whereas gene numbers and structures are well conserved in the ABCD, ABCE, ABCF, and ABCH subfamilies. Microarray analysis revealed that expression of 32 silkworm ABC genes can be detected in at least one tissue during different developmental stages, and the expression patterns of some of them were confirmed by quantitative real-time PCR. A large number of ABC genes were highly expressed in the testis compared to other tissues. One of the ABCG genes, <it>BmABC002712</it>, was exclusively and abundantly expressed in the Malpighian tubule implying that <it>BmABC002712 </it>plays a tissue-specific role. At least 5 ABCG genes, including <it>BmABC005226</it>, <it>BmABC005203</it>, <it>BmABC005202</it>, <it>BmABC010555</it>, and <it>BmABC010557</it>, were preferentially expressed in the midgut, showing similar developmental expression profiles to those of 20-hydroxyecdysone (20E)-response genes. 20E treatment induced the expression of these ABCG genes in the midgut and RNA interference-mediated knockdown of <it>USP</it>, a component of the 20E receptor, decreased their expression, indicating that these midgut-specific ABCG genes are 20E-responsive.</p> <p>Conclusion</p> <p>In this study, a genome-wide analysis of the silkworm ABC transporters has been conducted. A comparison of ABC transporters from 5 insect species provides an overview of this vital gene superfamily in insects. Moreover, tissue- and stage-specific expression data of the silkworm ABCG genes lay a foundation for future analysis of their physiological function and hormonal regulation.</p

A Robust Cooperative Spectrum Sensing-Assisted Multiuser Resource Allocation Scheme

Cognitive radio (CR), which is proposed as a solution for spectrum scarcity, imposes some threats to the network. One severe attack to cognitive radio network is the primary user emulation attack (PUEA), in which an attacker may transmit its signal with high power or mimic specific features of the primary user&apos;s signal to prevent secondary users from accessing the licensed spectrum. In this paper, we study a subcarrier and power allocation problem for orthogonal frequency division multiple access-(OFDMA-) based CR systems in the presence of PUEA. To maximize the system throughput while keeping the interference introduced to the primary user (PU) below given thresholds with a certain probability, a joint design of a robust cooperative spectrum sensing and a resource allocation scheme is proposed. In the proposed scheme, the inaccurate classification of PU signals and PUEA signals provided by robust cooperative spectrum sensing is utilized by resource scheduling module. To further exploit the underutilized spectrum bands, we also evaluate the performance of the proposed scheme in the hybrid overlay/underlay spectrum access mechanism. Numerical results demonstrate the effectiveness of the proposed scheme compared to conventional scheme regardless of the number of SUs or the kind of spectrum access mechanism being used

Hyperspectral Imaging for the Detection of Vitamin C Content in Potatoes Based on Fisher Discriminant Analysis Separable Information Fusion

In order to improve the accuracy and reliability of the prediction results of the vitamin C (VC) content in potatoes by hyperspectral imaging, a method for constructing input variables for predictive models based on Fisher discriminant analysis (FDA) separable data fusion was proposed. First, hyperspectral information of 200 potato samples was collected by hyperspectral imaging technology, and by comparing the modeling results obtained with the spectral data before and after preprocessing by 6 spectral preprocessing methods, multiplicative scatter correction (MSC) was determined as the optimal preprocessing method. Second, competitive adaptive reweighted sampling (CARS), successive projections algorithm (SPA) and CARS-SPA algorithm were used to extract the feature wavelengths, and 34 effective feature wavelengths were finally determined through comparative analysis. Third, the effective feature wavelengths were fused by FDA to achieve data separability, and the fused new variables were screened for their capacity to discriminate the differences among samples in order to determine the input variables for predictive models. Finally, predictive models using partial least squares (PLS) and back propagation neural network (BPNN) were established based on the variables selected before and after FDA fusion, and the results from these models were compared and analyzed. It was shown that the correlation coefficient of the BPNN model increased from 0.972 6 to 0.999 0, and the root mean square error (RMSE) reduced from 0.772 3 to 0.172 7 when the 34 effective feature wavelengths extracted by CARS were used for FDA fusion and the first three fused variables were used as the input variables, which not only greatly reduced data dimensionality, but also improved the accuracy of the detection results. Therefore, constructing input variables for the detection model based on FDA separable data fusion could improve the accuracy of the detection of potato VC content

Fluid flow-induced activation of subcellular AMPK and its interaction with FAK and Src

AMP-activated protein kinase (AMPK) is a metabolic energy sensor that plays a critical role in cancer cell survival and growth. While the physical microenvironment is believed to influence tumor growth and progression, its role in AMPK regulation remains largely unknown. In the present study, we evaluated AMPK response to mechanical forces and its interaction with other mechano-responsive signaling proteins, FAK and Src. Using genetically encoded biosensors that can detect AMPK activities at different subcellular locations (cytosol, plasma membrane, nucleus, mitochondria, and Golgi apparatus), we observed that AMPK responds to shear stress in a subcellular location-dependent manner in breast cancer cells (MDA-MB-231). While normal epithelial cells (MCF-10A) also similarly responded to shear stress, they are less sensitive to shear stress compared to MDA-MB-231 cells. Inhibition of FAK and Src significantly decreased the basal activity level of AMPK at all five subcellular locations in MDA-MB-231 cells and selectively blocked shear stress-induced AMPK activation. Moreover, testing with cytoskeletal drugs revealed that myosin II might be the critical mediator of shear stress-induced AMPK activation in MDA-MB-231 cells. These findings suggest that breast cancer cells and normal epithelial cells may have different mechanosensitivity in AMPK signaling and that FAK and Src as well as the myosin II-dependent signaling pathway are involved in subcellular AMPK mechanotransduction in breast cancer cells

Effects of a checkpoint kinase inhibitor, AZD7762, on tumor suppression and bone remodeling

Chemotherapy for suppressing tumor growth and metastasis tends to induce various effects on other organs. Using AZD7762, an inhibitor of checkpoint kinase (Chk) 1 and 2, the present study examined its effect on mammary tumor cells in addition to bone cells (osteoclasts, osteoblasts and osteocytes), using monolayer cell cultures and three-dimensional (3D) cell spheroids. The results revealed that AZD7762 blocked the proliferation of 4T1.2 mammary tumor cells and suppressed the development of RAW264.7 pre-osteoclast cells by downregulating nuclear factor of activated T cells cytoplasmic 1. AZD7762 also promoted the mineralization of MC3T3 osteoblast-like cells and 3D bio-printed bone constructs of MLO-A5 osteocyte spheroids. While a Chk1 inhibitor, PD407824, suppressed the proliferation of tumor cells and the differentiation of pre-osteoclasts, its effect on gene expression in osteoblasts was markedly different compared with AZD7762. Western blotting indicated that the stimulating effect of AZD7762 on osteoblast development was associated with the inhibition of Chk2 and the downregulation of cellular tumor antigen p53. The results of the present study indicated that in addition to acting as a tumor suppressor, AZD7762 may prevent bone loss by inhibiting osteoclastogenesis and stimulating osteoblast mineralization

METABOLIC CHANGES INDUCED BY BUSHENHUOXUE GRANULES ON STRIATUM AND SUBSTANTIA NIGRA IN A RAT MODEL OF PARKINSON’S DISEASE

Background: Parkinson’s disease is a neurodegenerative disease, while its mechanism is still unclear. Long-term levodopa-based treatment leads to decreased response or loss of response, as well as severe side effects. Our previous study has proved that Bushenhuoxue Granules have effects on Parkinson’s disease, but the underlying mechanism is still need to be explored. Our research is to investigate the mechanisms of Bushenhuoxue Granules on Parkinson’s disease (PD) by examining changes in the expression of the adenosine A2A receptor、vesicular monoamine transporter 2 (VMAT2)、divalent metal transporter 1(DMT1) and nuclear factor E2 related (Nrf2) in a rat model of Parkinson’s disease (PD) . Materials and Methods: Changes in the apomorphine (APO)-induced rotational behavior of rats were observed after treatment. Immunofluorescence and immunohistochemistry were performed to investigate changes in adenosine A2A receptor 、VMAT2、DMT1 and Nrf2 expression in the rat striatum and substantia nigra. Results: Rotations after treatment were199.11 ± 27.16, which significantly decreased compared with that before treatment ( 273.0 ± 44.61, p < 0.01). Adenosine A2A receptor expression in the striatum was 3.10 ± 0.34 significantly increased in the model group and decreased in the normal control group, whereas the expression level in the Bushenhuoxue group was 1.13 ± 0.23,p < 0.05 between the two control groups. No adenosine A2A receptor expression was observed in the substantia nigra. VMAT2 expression in the rat striatum was 23.20 ± 2.68 and substantia nigra was 15.98 ± 0.70 increased in the normal control group. They were 8.99 ± 0.48 in the rat striatum and 8.45 ± 0.59 substantia nigra significantly decreased in the model control group, whereas the expression level in the Bushenhuoxue group was 15.36 ± 0.89 in the rat striatum and 11.69 ± 1.17 in the rat substantia nigra (p < 0.05), also between the two control groups. DMT1 expression in the rat striatum was 3.30 ± 0.30 and substantia nigra was 6.56 ± 0.64 decreased in the normal control group. They were 7.92 ± 0.52 in the rat striatum and 12.76 ± 0.86 substantia nigra significantly increased in the model control group, whereas the expression level in the Bushenhuoxue group was 6.17 ± 0.27 in the rat striatum and 9.13 ± 0.44 in the rat substantia nigra (p < 0.05), also between the two control groups. Nrf2 expression in the rat striatum was 7.90 ± 0.29 and substantia nigra was 15.22 ± 1.22 increased in the normal control group. They were 3.09 ± 0.43 in the rat striatum and 8.57 ± 0.54 substantia nigra significantly decreased in the model control group, whereas the expression level in the Bushenhuoxue group was 5.00 ± 0.34 in the rat striatum and 12.46 ± 0.62 in the rat substantia nigra (p< 0.05), also between the two control groups. Conclusion: Bushenhuoxue Granules significantly improved the rotational behavior of PD’s rats, decreased adenosine A2A receptor expression, and increased VMAT2 expression; decreased DMT1 expression, and increased Nfr2 expression

PERK-Mediated Cholesterol Excretion from IDH Mutant Glioma Determines Anti-Tumoral Polarization of Microglia

Isocitrate dehydrogenase (IDH) mutation, a known pathologic classifier, initiates metabolic reprogramming in glioma cells and has been linked to the reaction status of glioma-associated microglia/macrophages (GAMs). However, it remains unclear how IDH genotypes contribute to GAM phenotypes. Here, it is demonstrated that gliomas expressing mutant IDH determine M1-like polarization of GAMs, while archetypal IDH induces M2-like polarization. Intriguingly, IDH-mutant gliomas secrete excess cholesterol, resulting in cholesterol-rich, pro-inflammatory GAMs without altering their cholesterol biosynthesis, and simultaneously exhibiting low levels of tumoral cholesterol due to expression remodeling of cholesterol transport molecules, particularly upregulation of ABCA1 and downregulation of LDLR. Mechanistically, a miR-19a/LDLR axis-mediated novel post-transcriptional regulation of cholesterol uptake is identified, modulated by IDH mutation, and influencing tumor cell proliferation and invasion. IDH mutation-induced PERK activation enhances cholesterol export from glioma cells via the miR-19a/LDLR axis and ABCA1/APOE upregulation. Further, a synthetic PERK activator, CCT020312 is introduced, which markedly stimulates cholesterol efflux from IDH wild-type glioma cells, induces M1-like polarization of GAMs, and consequently suppresses glioma cell invasion. The findings reveal an essential role of the PERK/miR-19a/LDLR signaling pathway in orchestrating gliomal cholesterol transport and the subsequent phenotypes of GAMs, thereby highlighting a novel potential target pathway for glioma therapy

Integrative single-cell RNA sequencing and metabolomics decipher the imbalanced lipid-metabolism in maladaptive immune responses during sepsis

BackgroundTo identify differentially expressed lipid metabolism-related genes (DE-LMRGs) responsible for immune dysfunction in sepsis.MethodsThe lipid metabolism-related hub genes were screened using machine learning algorithms, and the immune cell infiltration of these hub genes were assessed by CIBERSORT and Single-sample GSEA. Next, the immune function of these hub genes at the single-cell level were validated by comparing multiregional immune landscapes between septic patients (SP) and healthy control (HC). Then, the support vector machine-recursive feature elimination (SVM-RFE) algorithm was conducted to compare the significantly altered metabolites critical to hub genes between SP and HC. Furthermore, the role of the key hub gene was verified in sepsis rats and LPS-induced cardiomyocytes, respectively.ResultsA total of 508 DE-LMRGs were identified between SP and HC, and 5 hub genes relevant to lipid metabolism (MAPK14, EPHX2, BMX, FCER1A, and PAFAH2) were screened. Then, we found an immunosuppressive microenvironment in sepsis. The role of hub genes in immune cells was further confirmed by the single-cell RNA landscape. Moreover, significantly altered metabolites were mainly enriched in lipid metabolism-related signaling pathways and were associated with MAPK14. Finally, inhibiting MAPK14 decreased the levels of inflammatory cytokines and improved the survival and myocardial injury of sepsis.ConclusionThe lipid metabolism-related hub genes may have great potential in prognosis prediction and precise treatment for sepsis patients