Human tumorous imaginal disc (Tid1), a DnaJ co-chaperone protein, is classified as a tumor suppressor. Previously, we demonstrated that Tid1 reduces head and neck squamous cell carcinoma (HNSCC) malignancy. However, the molecular details of Tid1-mediated anti-metastasis remain elusive.Methods: We used affinity chromatography and systemic mass spectrometry to identify Tid1-interacting client proteins. Immunohistochemical staining of Tid1 in HNSCC patient tissues was examined to evaluate the association between the expression profile of Tid1-interacting client proteins with pathologic features and prognosis. The roles of Tid1-interacting client proteins in metastasis were validated both in vitro and in vivo. The interacting partner and downstream target of Tid1-interacting client protein were determined.Results: Herein, we first revealed that Galectin-7 was one of the Tid1-interacting client proteins. An inverse association of protein expression profile between Tid1 and Galectin-7 was determined in HNSCC patients. Low Tid1 and high Galectin-7 expression predicted poor overall survival in HNSCC. Furthermore, Tid1 abolished the nuclear translocation of Galectin-7 and suppressed Galectin-7-induced tumorigenesis and metastasis. Keratinocyte-specific Tid1-deficient mice with 4-nitroquinoline-1-oxide (4NQO) treatment exhibited increased protein levels of Galectin-7 and had a poor survival rate. Tid1 interacted with Galectin-7 through its N-linked glycosylation to promote Tid1-mediated ubiquitination and proteasomal degradation of Galectin-7. Additionally, Galectin-7 played a critical role in promoting tumorigenesis and metastatic progression by enhancing the transcriptional activity of TCF3 transcription factor through elevating MMP-9 expression.Conclusions: Overall, future treatments through activating Tid1 expression or inversely repressing the oncogenic function of Galectin-7 may exhibit great potential in targeting HNSCC progression.
Rotational rheometer has been widely used in studying rheological properties of materials. However, the conventional rheological measurements may not be applicable for some non-traditional materials with characteristic properties. Polycarbosilane (PCS) is an oligomer and in the form of solid state at room temperature. A large amount of air bubbles are evolved during the heating process of PCS, which is extremely harmful for rheological measurements of PCS melt and detrimentally influences the accuracy of rheological data. In this work, a series of PCS raw samples were pretreated with different heating processes by the advanced rheometric expansion system at 315°C before the rheological measurements at 295°C. The softening point temperatures and molecular weight distributions of different PCS samples were obtained before and after the preheating processes. The experimental data collected with the in-situ preheating and ex-situ preheating for 1 h were compared.
As an important precursor in preparation of silicon carbide ceramic fibers by polymer precursor-derived method, it is very difficult to find the zero shear viscosity through the conventional steady test for the oligomer-like polycarbosilane (PCS) because of the possible oxidation and a prolonged time required to attain a steady state of the samples. In this work, a steady test and a series of transient tests were performed for the PCS melts. The limitation of the steady test is discussed. An averaging method based upon data from the transient tests is developed to determine the zero shear viscosity for the melt. The reliability of the results from the method is discussed and the zero shear viscosity of the pretreated PCS melt was obtained.
Dynamic Time Sweep of Rotational Rheometer has been Used to Study the Variation in Rheological Properties of Polymers with Time. Polycarbosilane (PCS) is a Solid Oligomer at Room Temperature and Becomes Melt at its Softening Temperature. Bubbles are Unavoidably Produced by Gasification of Low Molecular Weight Part of PCS, which Significantly Disturbs the Subsequent Rheological Measurement. however, the Rheological Data of PCS Melt Cannot Be Repeated on Conventional Dynamic Time Sweep Test even after Reducing the Bubble. in this Work, a Series of Oscillatory Rheological Measurements were Carried out by Temperature Control to Improve the Data Reliability. the Axial Force Data of PCS Melt were Manually Recorded and Compared before and during the Test, which Reflected the Response of PCS Melt to Temperature Change. the Results Confirmed that the Shear Stress of PCS Melt was Readily Affected by Temperature Alteration. the Data Repeatability of the Rheological Test was Evidently Improved for PCS Melt with the Temperature Control.
Shear stress-shear strain rate and shear stress-shear time curves of epoxy resin samples with the number average molecular weight of 283 g/mol were measured at 50 °C under the modes of steady test and transient test, respectively. Effects of dealy time (t1) and measurement time (t2) on the shear stress-shear responses of the epoxy resin oligomer material were studied. It was found that the repeatability of the test results at small shear rates was significantly influenced by the delay time and the measurement time. The values of t1 and t2 parameters to be used for the steady test of epoxy resin oligomer material could be optimized based upon the transient test. The measurement repeatablity at shear rates smaller than 7 s-1 was apparently improved by setting the delay time and the measurement time longer than 20 s seperately (t1 ³ 20 s, t2 ³ 20 s) with the total delay time and the measurement time shorter than 80 s (t1 + t2 £ 80s).
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