PRL-3 promotes the motility, invasion, and metastasis of LoVo colon cancer cells through PRL-3-integrin β1-ERK1/2 and-MMP2 signaling

<p>Abstract</p> <p>Background</p> <p>Phosphatase of regenerating liver-3 (PRL-3) plays a causative role in tumor metastasis, but the underlying mechanisms are not well understood. In our previous study, we observed that PRL-3 could decrease tyrosine phosphorylation of integrin β1 and enhance activation of ERK1/2 in HEK293 cells. Herein we aim to explore the association of PRL-3 with integrin β1 signaling and its functional implications in motility, invasion, and metastasis of colon cancer cell LoVo.</p> <p>Methods</p> <p>Transwell chamber assay and nude mouse model were used to study motility and invasion, and metastsis of LoVo colon cancer cells, respectively. Knockdown of integrin β1 by siRNA or lentivirus were detected with Western blot and RT-PCR. The effect of PRL-3 on integrin β1, ERK1/2, and MMPs that mediate motility, invasion, and metastasis were measured by Western blot, immunofluorencence, co-immunoprecipitation and zymographic assays.</p> <p>Results</p> <p>We demonstrated that PRL-3 associated with integrin β1 and its expression was positively correlated with ERK1/2 phosphorylation in colon cancer tissues. Depletion of integrin β1 with siRNA, not only abrogated the activation of ERK1/2 stimulated by PRL-3, but also abolished PRL-3-induced motility and invasion of LoVo cells in vitro. Similarly, inhibition of ERK1/2 phosphorylation with U0126 or MMP activity with GM6001 also impaired PRL-3-induced invasion. In addition, PRL-3 promoted gelatinolytic activity of MMP2, and this stimulation correlated with decreased TIMP2 expression. Moreover, PRL-3-stimulated lung metastasis of LoVo cells in a nude mouse model was inhibited when integrin β1 expression was interfered with shRNA.</p> <p>Conclusion</p> <p>Our results suggest that PRL-3's roles in motility, invasion, and metastasis in colon cancer are critically controlled by the integrin β1-ERK1/2-MMP2 signaling.</p

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

Potential options for managing LOX+ ER− breast cancer patients

Overexpression of lysyl oxidase (LOX) is often observed in estrogen receptor negative (ER–) breast cancer patients with bone metastasis. In the present bioinformatics study, we observed that LOX is a prognostic factor for poor progression free survival in patients with ER– breast cancer. LOX overexpression was positively correlated with resistance to radiation, doxorubin and mitoxantrone, but negatively correlated with resistance to bisphosphonate, PARP1 inhibitors, cisplatin, trabectedin and gemcitabine. LOX overexpression was also associated with EMT and stemness of cancer cells, which leads to chemotherapeutic resistance and poor outcome in ER– patients. Although we suggest several therapeutic interventions that may help in the management of LOX+ ER– breast cancer patients, experiments to validate the function of LOX in ER– breast cancer are still needed

Antibody Array Revealed PRL-3 Affects Protein Phosphorylation and Cytokine Secretion

<div><p>Phosphatase of regenerating liver 3 (PRL-3) promotes cancer metastasis and progression via increasing cell motility and invasiveness, however the mechanism is still not fully understood. Previous reports showed that PRL-3 increases the phosphorylation of many important proteins and suspected that PRL-3-enhanced protein phosphorylation may be due to its regulation on cytokines. To investigate PRL-3’s impact on protein phosphorylation and cytokine secretion, we performed antibody arrays against protein phosphorylation and cytokines separately. The data showed that PRL-3 could enhance tyrosine phosphorylation and serine/threonine phosphorylation of diverse signaling proteins. Meanwhile, PRL-3 could affect the secretion of a subset of cytokines. Furthermore, we discovered the PRL-3-increased IL-1α secretion was regulated by NF-κB and Jak2-Stat3 pathways and inhibiting IL-1α could reduce PRL-3-enhanced cell migration. Therefore, our result indicated that PRL-3 promotes protein phosphorylation by acting as an ‘activator kinase’ and consequently regulates cytokine secretion.</p></div

The top 20 phosphoproteins experiencing changes in phosphorylation in the PRL-3 overexpressing cells.

<p>The top 20 phosphoproteins experiencing changes in phosphorylation in the PRL-3 overexpressing cells.</p

Overexpression of PRL-3 widely increased protein phosphorylation.

<p>(A) Confirmation of PRL-3 overexpression in HCT116 and LoVo cells. (B) Several phosphoproteins increased by PRL-3 in HCT116 and LoVo cells. (C) PRL-3’s wide impact on the whole protein phosphorylation, including tyrosine phosphorylation and serine/threonine phosphorylation in HCT116 and LoVo cells. (D) PRL-3’s impacts on phosphorylations of EGFR, p65, and ERK in eight colorectal cancer tissues.</p

Identification of significant pathways regulated by PRL-3.

<p>(A) Significant KEGG pathways identified by DAVID when PRL-3 was overexpressed in HCT116 cells. The left-side ordinate values are -lg (Benjamini-Hochberg p-value), while the right-side ordinate values are the ratios of phosphorylated proteins in the total significantly regulated phosphoproteins. (B) Heatmaps of several pathways to show the phosphoproteins regulated by PRL-3, including ErbB signaling pathway, Focal adhesion, MAPK signaling pathway and Chemokine signaling pathway. The red color represents the phosphorylation of the protein was increased in PRL-3 overexpressing cells, while the blue color represents the phosphorylation of the protein was decreased in PRL-3 overexpressing cells.</p

IL-1α participates in PRL-3 induced cell migration.

<p>(A) and (B) IL-1α was regulated by PRL-3 through NF-κB and Jak2-STAT3 signaling pathways. (A) The treatment of HCT116 cells with 10 μM BAY11-7082 for 24 hours reduced PRL-3-increased p-p65 (S536), and the treatment of HCT116 cells with 2 μM AG490 for 24 hours reduced PRL-3-increased p-STAT3 (Y705) while the treatment of HCT116 cells with 100 ng/mL IL-6 for 24 hours increased p-p65 (S536) and p-STAT3 (Y705). (B) The treatment of HCT116 cells with 10 μM BAY11-7082 or 2 μM AG490 for 24 hours reduced PRL-3-increased IL-1α, and the treatment of HCT116 cells with 100 ng/mL IL-6 for 24 hours enhanced PRL-3-induced IL-1α secretion. (C) The treatment of HCT116 cells with 5 ng/mL IL-1RN for 48 hours decreased PRL-3-induced HCT116 cell migration. (D) Inhibition of IL-1α by siRNA interference decreased PRL-3-induced HCT116 cell migration. The values are the mean and standard deviation, * p < 0.05, ** p < 0.01, *** p < 0.001; n = 3.</p

Significantly regulated cytokines by PRL-3.

<p>(A) Significantly regulated cytokines were all increased in PRL-3 overexpressing HCT116 cells. (B) The mRNA levels of several regulated cytokines were increased in PRL-3 overexpressing HCT116 and LoVo cells. (C) Relative levels of GDF-15, IL-1α and NPY in the supernatants of PRL-3 overexpressing HCT116 and LoVo cells and corresponding control cells. The values are the mean and standard deviation, *p <0.05, **p <0.01; n = 3.</p