Aging pattern of the brainstem based on volumetric measurement and optimized surface shape analysis.

The brainstem, a small and crucial structure, is connected to the cerebrum, spinal cord, and cerebellum, playing a vital role in regulating autonomic functions, transmitting motor and sensory information, and modulating cognitive processes, emotions, and consciousness. While previous research has indicated that changes in brainstem anatomy can serve as a biomarker for aging and neurodegenerative diseases, the structural changes that occur in the brainstem during normal aging remain unclear. This study aimed to examine the age- and sex-related differences in the global and local structural measures of the brainstem in 187 healthy adults (ranging in age from 18 to 70 years) using structural magnetic resonance imaging. The findings showed a significant negative age effect on the volume of the two major components of the brainstem: the medulla oblongata and midbrain. The shape analysis revealed that atrophy primarily occurs in specific structures, such as the pyramid, cerebral peduncle, superior and inferior colliculi. Surface area and shape analysis showed a trend of flattening in the aging brainstem. There were no significant differences between the sexes or sex-by-age interactions in brainstem structural measures. These findings provide a systematic description of age associations with brainstem structures in healthy adults and may provide a reference for future research on brain aging and neurodegenerative diseases.

Evaluating the Impact of Intracranial Volume Correction Approaches on the Quantification of Intracranial Structures in MRI: A Systematic Analysis.

BACKGROUND: In neuroscience, accurately quantifying individual brain regions in large cohorts is a challenge. Differences in intracranial structures can suggest functional differences, but they also reflect the effects of other factors. However, there is currently no standardized method for the correction of intracranial structure measurements. PURPOSE: To identify the optimal method to counteract the influence of total intracranial volume (TIV) and gender on the measurement of intracranial structures. STUDY TYPE: Prospective. POPULATION/SUBJECTS: One hundred forty-one healthy adult volunteers (70 male, mean age 21.8 ± 1.7 years). FIELD STRENGTH/SEQUENCE: T1-weighted 3D gradient-echo sequence at 3.0 T. ASSESSMENT: A radiologist with 5 years of work experience screened the raw images to exclude poor-quality images. Freesurfer then performed automated segmentation to obtain measurements of intracranial structures. Male-only, female-only, and TIV-matched sub-samples were created separately. Comparisons between the original data and these sub-samples were used to assess the effects of gender and TIV. Comparison the consistency between TIV-matched sample and corrected data that corrected by four methods: Proportion method, power-corrected proportion method, covariate regression method, and residual method. STATISTICAL TESTS: Cohen's d for examining group distribution disparities, t-tests for probing mean differences, correlation coefficients to assess the relationships between intracranial substructure measurements and TIV. Multiple comparison corrections were applied to the results. RESULTS: The correlation coefficients between TIV and the volumes of intracranial structures ranged from 0.033 to 0.883, with an average of 0.467. Thirty significant volume differences were found among 36 structures in the original sample, while no differences were observed in the TIV-matched sample. Among the four correction methods, the residual method had highest consistency (similarity 94.4%) with the TIV-matched group. DATA CONCLUSION: The variation in intracranial structure sizes between genders was largely attributable to TIV. The residual method offers a more accurate and effective approach for correcting the effects of TIV on intracranial structures. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Lung Transplantation: A Viable Option for Connective Tissue Disease?

Interstitial lung disease (ILD) and pulmonary hypertension (PH) caused by connective tissue disease (CTD) are one of the main causes of morbidity and death in patients. Although the International Society for Heart & Lung Transplant suggested that ILD and PH related to CTD are rare indications for lung transplantation in 2006, many lung transplantation centers are concerned that the multisystem involvement of CTD will affect survival outcomes after lung transplantation, and CTD is regarded as a relative contraindication for lung transplantation. However, long-term and short-term survival after lung transplantation in CTD patients is similar compared with survival in common indications for lung transplantation such as idiopathic pulmonary fibrosis (IPF), and no higher incidence of complications after transplantation in many lung transplant centers. This suggests that lung transplantation may be beneficial in CTD patients with disease that progresses to end-stage lung disease, and CTD should not be considered a contraindication for lung transplantation. In the future, more prospective studies are needed to analyze the risk factors of lung transplantation in CTD patients to improve survival rates and reduce the risk of complications. This narrative review summarizes the selection and evaluation of candidates for CTD before lung transplantation and describes the clinical outcomes in CTD after lung transplantation in large-capacity lung transplantation center. The purpose of this review is to help rheumatologists decide when to refer patients with CTD-related lung involvement to a lung transplantation center and the conditions to consider before transplantation and to provide confidence to lung transplant experts.

Correction: Cbl-b inhibits P-gp transporter function by preventing its translocation into caveolae in multiple drug-resistant gastric and breast cancers.

[This corrects the article DOI: 10.18632/oncotarget.3253.].

Dual inhibition of MET and SRC kinase activity as a combined targeting strategy for colon cancer.

Hepatocyte growth factor (HGF)/MET signaling is implicated in the development of colorectal cancer (CRC) and possesses therapeutic value for various types of cancer. However, inhibition of MET alone has been demonstrated to have limited efficacy. The present study examined the combined inhibition of MET and SRC kinase activity in colon cancer cells. Furthermore, the role of the HGF/MET pathway in ligand-dependent and -independent activation was demonstrated. The single inhibition of MET by knockdown small interfering RNA or inhibitor indicated a limited anti-viability effects without inhibiting the basal phosphorylation levels of SRC, protein kinase B (AKT) or extracellular signal-regulated kinase (ERK). In view of the strong association between MET and SRC identified by direct regulation, growth factor-induced MET activation was suppressed by pretreatment with the SRC inhibitor, dasatinib, and downstream phosphorylation of AKT and ERK partially decreased, which suggested that SRC activation was essential for ligand-dependent and -independent activation of MET. Considering that both the activation of MET and SRC was required in ligand-dependent and -independent MET activation, the antitumor effect of concurrent inhibition of MET and SRC was examined, and it was demonstrated that combination treatment exerted increased viability inhibition and apoptosis enhancement in mutant and wild type RAS colon cancer cells. Therefore, combinational inhibition of MET and SRC may be a promising strategy for the treatment of CRC.

Bufalin inhibits TGF-ß-induced epithelial-to-mesenchymal transition and migration in human lung cancer A549 cells by downregulating TGF-ß receptors.

The epithelial-to-mesenchymal transition (EMT) is a well-known prerequisite for cancer cells to acquire the migratory and invasive capacity, and to subsequently metastasize. Bufalin is one of the major active components of the traditional Chinese medicine Chan Su, and accumulating evidence has shown its anticancer effect in multipe types of cancer. However, the role of bufalin in transforming growth factor­ß (TGF­ß)­induced EMT and migration remains unclear. In the present study, the effect of bufalin on TGF­ß­induced EMT and migration was investigated in human lung cancer A549 cells. TGF­ß induced EMT in A549 cells and increased their migratory ability, which were markedly suppressed by bufalin. Additionally, TGF­ß­induced upregulation of Twist2 and zinc finger E­box binding homeobox 2 (ZEB2), as well as the phosphorylation of Smad2 and Smad3 were also inhibited by bufalin. However, the Smad­independent signaling pathways were not affected. Further analysis showed that the TGF­ß receptor I (TßRI) and TGF­ß receptor II (TßRII) were downregulated in the presence of bufalin. Pretreatment with SB431542, a potent inhibitor of the phosphorylation of TßRI, significantly attenuated TGF­ß­induced EMT, mimicking the effect of bufalin on A549 cells. Taken together, these results suggest that bufalin suppresses TGF-ß-induced EMT and migration by downregulating TßRI and TßRII in A549 cells.

Construction of an all-carbon quaternary stereocenter by organocatalytic enantioselective α-functionalization of α-substituted ß-ketocarbonyls with electron deficient vinylarenes.

A chiral amine catalyzed enantioselective α-functionalization of α-substituted ß-ketocarbonyls with electron-deficient vinylarenes has been developed to construct the dicarbonyl products with the formation of a chiral all-carbon quaternary stereocenter. The products can be used for the efficient synthesis of useful but challenging chiral quaternary centered pyrazolones.

Cbl-b inhibits P-gp transporter function by preventing its translocation into caveolae in multiple drug-resistant gastric and breast cancers.

The transport function of P-glycoprotein (P-gp) requires its efficient localization to caveolae, a subset of lipid rafts, and disruption of caveolae suppresses P-gp transport function. However, the regulatory molecules involved in the translocation of P-gp into caveolae remain unknown. In the present study, we showed that c-Src dependent Caveolin-1 phosphorylation promoted the translocation of P-gp into caveolae, resulting in multidrug resistance in adriamycin resistant gastric cancer SGC7901/Adr and breast cancer MCF-7/Adr cells. In a negative feedback loop, the translocation of Cbl-b from the nucleus to the cytoplasm prevented the localization of P-gp to caveolae resulting in the reversal of MDR through the ubiquitination and degradation of c-Src. Clinical data showed a significant positive relationship between Cbl-b expression and survival in P-gp positive breast cancer patients who received anthracycline-based chemotherapy. Our findings identified a new regulatory mechanism of P-gp transport function in multiple drug-resistant gastric and breast cancers.

Cetuximab-induced MET activation acts as a novel resistance mechanism in colon cancer cells.

Aberrant MET expression and hepatocyte growth factor (HGF) signaling are implicated in promoting resistance to targeted agents; however, the induced MET activation by epidermal growth factor receptor (EGFR) inhibitors mediating resistance to targeted therapy remains elusive. In this study, we identified that cetuximab-induced MET activation contributed to cetuximab resistance in Caco-2 colon cancer cells. MET inhibition or knockdown sensitized Caco-2 cells to cetuximab-mediated growth inhibition. Additionally, SRC activation promoted cetuximab resistance by interacting with MET. Pretreatment with SRC inhibitors abolished cetuximab-mediated MET activation and rendered Caco-2 cells sensitive to cetuximab. Notably, cetuximab induced MET/SRC/EGFR complex formation. MET inhibitor or SRC inhibitor suppressed phosphorylation of MET and SRC in the complex, and MET inhibitor singly led to disruption of complex formation. These results implicate alternative targeting of MET or SRC as rational strategies for reversing cetuximab resistance in colon cancer.

PRP19 transforms into a sensor of RPA-ssDNA after DNA damage and drives ATR activation via a ubiquitin-mediated circuitry.

PRP19 is a ubiquitin ligase involved in pre-mRNA splicing and the DNA damage response (DDR). Although the role for PRP19 in splicing is well characterized, its role in the DDR remains elusive. Through a proteomic screen for proteins that interact with RPA-coated single-stranded DNA (RPA-ssDNA), we identified PRP19 as a sensor of DNA damage. PRP19 directly binds RPA and localizes to DNA damage sites via RPA, promoting RPA ubiquitylation in a DNA-damage-induced manner. PRP19 facilitates the accumulation of ATRIP, the regulatory partner of the ataxia telangiectasia mutated and Rad3-related (ATR) kinase, at DNA damage sites. Depletion of PRP19 compromised the phosphorylation of ATR substrates, recovery of stalled replication forks, and progression of replication forks on damaged DNA. Importantly, PRP19 mutants that cannot bind RPA or function as an E3 ligase failed to support the ATR response, revealing that PRP19 drives ATR activation by acting as an RPA-ssDNA-sensing ubiquitin ligase during the DDR.

Nek1 kinase associates with ATR-ATRIP and primes ATR for efficient DNA damage signaling.

The master checkpoint kinase ATR (ATM and Rad3-related) and its partner ATRIP (ATR-interacting protein) exist as a complex and function together in the DNA damage response. Unexpectedly, we found that the stability of the ATR-ATRIP complex is regulated by an unknown kinase independently of DNA damage. In search for this regulator of ATR-ATRIP, we found that a single member of the NIMA (never in mitosis A)-related kinase family, Nek1, is critical for initiating the ATR response. Upon DNA damage, cells lacking Nek1 failed to efficiently phosphorylate multiple ATR substrates and support ATR autophosphorylation at threnine 1989, one of the earliest events during the ATR response. The ability of Nek1 to promote ATR activation relies on the kinase activity of Nek1 and its interaction with ATR-ATRIP. Importantly, even in undamaged cells, Nek1 is required for maintaining the levels of ATRIP, the association between ATR and ATRIP, and the basal kinase activity of ATR. Thus, as an ATR-associated kinase, Nek1, enhances the stability and activity of ATR-ATRIP before DNA damage, priming ATR-ATRIP for a robust DNA damage response.

The conserved C terminus of Claspin interacts with Rad9 and promotes rapid activation of Chk1.

Claspin is a key mediator of the ATR-Chk1 checkpoint pathway. In response to DNA damage, Claspin interacts with Rad17 and Chk1 in a phosphorylation-dependent manner, enabling ATR to phosphorylate Chk1 efficiently. Claspin also interacts with Rad9, but how they interact and whether the interaction is functional remains unknown. Unexpectedly, our analysis of two splicing isoforms of Claspin provided an answer to these questions. The Claspin(1339) isoform contains an evolutionarily conserved C terminus, but the Claspin(1332) isoform does not. Although the transcripts encoding both Claspin isoforms coexist in HCT116 cells, Claspin(1339) is the predominant form responsible for Chk1 activation. When expressed in cells depleted of endogenous Claspin, both Claspin(1339) and Claspin(1332) are able to mediate Chk1 activation. However, the activation of Chk1 is delayed in Claspin(1332)-expressing cells compared with Claspin(1339)-expressing cells. Furthermore, only Claspin(1339) but not Claspin(1332) interacts with Rad9 efficiently. Together, these results suggest that the conserved C terminus of Claspin interacts with Rad9 and ensures timely activation of the ATR-Chk1 pathway.

ATR autophosphorylation as a molecular switch for checkpoint activation.

The ataxia telangiectasia-mutated and Rad3-related (ATR) kinase is a master checkpoint regulator safeguarding the genome. Upon DNA damage, the ATR-ATRIP complex is recruited to sites of DNA damage by RPA-coated single-stranded DNA and activated by an elusive process. Here, we show that ATR is transformed into a hyperphosphorylated state after DNA damage, and that a single autophosphorylation event at Thr 1989 is crucial for ATR activation. Phosphorylation of Thr 1989 relies on RPA, ATRIP, and ATR kinase activity, but unexpectedly not on the ATR stimulator TopBP1. Recruitment of ATR-ATRIP to RPA-ssDNA leads to congregation of ATR-ATRIP complexes and promotes Thr 1989 phosphorylation in trans. Phosphorylated Thr 1989 is directly recognized by TopBP1 via the BRCT domains 7 and 8, enabling TopBP1 to engage ATR-ATRIP, to stimulate the ATR kinase, and to facilitate ATR substrate recognition. Thus, ATR autophosphorylation on RPA-ssDNA is a molecular switch to launch robust checkpoint response.

Thalidomide improves prevention of chemotherapy-induced gastrointestinal side effects following a modified FOLFOX7 regimen: results of a prospective randomized crossover study.

AIMS AND BACKGROUND: Thalidomide was firstly evaluated for the control of chemotherapy-induced gastrointestinal side effects following a modified FOLFOX7 (mFOLFOX7) regimen. METHODS AND STUDY DESIGN: Chemotherapy-naive patients with malignant tumors were randomized into two groups: A-B group (A, 0.3 mg of ramosetron plus 10 mg of dexamethasone on day 1, was given intravenously in the first cycle, and B, 0.3 mg of ramosetron plus 10 mg of dexamethasone on day 1 intravenously plus 150 mg orally twice daily of thalidomide on days 2 through 5, in the second cycle) and B-A group (those drugs were given in the reverse sequence). The primary end point was the efficacy of thalidomide in controlling delayed (days 2 through 5) chemotherapy-induced nausea and vomiting (CINV). The secondary end point was the safety of thalidomide. RESULTS: Of 52 patients enrolled, 50 patients (96%) were assessable. Complete response rates of delayed nausea (no nausea) were higher with group B than group A (52% vs 24%, P = 0.004 on day 2; 58% vs 24%, P = 0.001 on day 3; and 60% vs 36%, P = 0.016 on day 4). Complete response rates of delayed emesis (no emetic episodes, no rescue therapy) for group B and A also showed significance (86% vs 66%, P = 0.019 on day 2 and 76% vs 56%, P = 0.035 on day 3). Complete response rates on anorexia for group B were higher than those for group A on days 2 through 5. More patients in group B reported sedation or dizziness than in group A (42% vs 9.6%; P = 0.000). CONCLUSIONS: Thalidomide improves prevention of chemotherapy-induced gastrointestinal side effects following the mFOLFOX7 regimen. It is a safe, effective antiemetic.

Claspin operates downstream of TopBP1 to direct ATR signaling towards Chk1 activation.

TopBP1 and Claspin are adaptor proteins that facilitate phosphorylation of Chk1 by the ATR kinase in response to genotoxic stress. Despite their established requirement for Chk1 activation, the exact way in which TopBP1 and Claspin control Chk1 phosphorylation remains unclear. We show that TopBP1 tightly colocalizes with ATR in distinct nuclear subcompartments generated by DNA damage. Although depletion of TopBP1 by RNA interference (RNAi) strongly impaired phosphorylation of multiple ATR targets, including Chk1, Nbs1, Smc1, and H2AX, it did not interfere with ATR assembly at the sites of DNA damage. These findings challenge the current concept of ATR activation by recruitment to damaged DNA. In contrast, Claspin, like Chk1, remained distributed throughout the nucleus both before and after DNA damage. Consistently, the RNAi-mediated ablation of Claspin selectively abrogated ATR's ability to phosphorylate Chk1 but not other ATR targets. In addition, downregulation of Claspin mimicked Chk1 inactivation by inducing spontaneous DNA damage. Finally, we show that TopBP1 is required for the DNA damage-induced interaction between Claspin and Chk1. Together, these results suggest that while TopBP1 is a general regulator of ATR, Claspin operates downstream of TopBP1 to selectively regulate the Chk1-controlled branch of the genotoxic stress response.

WT1 downregulation during K562 cell differentiation and apoptosis induced by bufalin.

OBJECTIVE: To study the change of WT1 gene expression during human leukemic K562 cell differentiation and apoptosis induced by bufalin. METHODS: Cell viability was determined by trypan blue exclusion, cell differentiation and apoptosis by nitro blue tetrazolium (NBT) reduction test, morphology and flow cytometry, expression of WT1 protein by Western blot analysis, and expression of WT1 mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: (1) The cell proliferation was inhibited by bufalin and the IC(50) at 24, 48, 72 h were 0.026, 0.032 and 0.006 micro mol/L, respectively. (2) Bufalin induced K562 cell differentiation towards macrophage/monocyte within concentration from 0.01 to 0.05 micro mol/L and apoptosis at higher than 0.026 micro mol/L. (3) The expression of WT1 protein and mRNA were downregulated by bufalin in the initial stage of differentiation and apoptosis induced by bufalin. CONCLUSION: K562 cell differentiation and apoptosis induced by bufalin might relate to the downregulation of WT1 expression.