Tat-NTS Suppresses The Proliferation, Migration and Invasion of Glioma Cells by Inhibiting Annexin-A1 Nuclear Translocation

Prevention of the nuclear translocation of Annexin-A1 with Tat-NTS (Trans-activator of transcription (Tat), nuclear translocation signal (NTS)) has recently been reported to alleviate neuronal injury and protect against cerebral stroke. However, the role that Tat-NTS plays in the occurrence and development of glioma still needs to be elucidated. Therefore, human glioma U87 cells were treated with various concentrations of Tat-NTS for 24 h, and cell proliferation, migration and invasion were determined with CCK-8 and Transwell assays, respectively. The results revealed that Tat-NTS significantly inhibited the nuclear translocation of Annexin-A1 in U87 cells, inhibited the proliferation, migration and invasion of U87 cells, and suppressed cell cycle regulatory protein expression and the activity and expression of MMP-2/MMP-9. Moreover, Tat-NTS reduced the level of p-p65 NF-κB in these cells. These results suggest that the Tat-NTS-induced inhibition of glioma cell proliferation, migration and invasion is closely associated with the induction of cell cycle arrest, the downregulation of MMP-2/-9 expression and activity and the suppression of the NF-κB signaling pathway. Thus, Tat-NTS may be a potential chemotherapeutic agent for the treatment of glioma.

The Cell-Cycle Regulatory Protein p21CIP1/WAF1 Is Required for Cytolethal Distending Toxin (Cdt)-Induced Apoptosis

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21CIP1/WAF1 in lymphoid cell lines, Jurkat and MyLa, and in primary human lymphocytes. These increases were dependent upon CdtB’s ability to function as a phosphatidylinositol (PI) 3,4,5-triphosphate (PIP3) phosphatase. It is noteworthy that Cdt-induced increases in the levels of p21CIP1/WAF1 were accompanied by a significant decline in the levels of phosphorylated p21CIP1/WAF1. The significance of Cdt-induced p21CIP1/WAF1 increase was assessed by preventing these changes with a two-pronged approach; pre-incubation with the novel p21CIP1/WAF1 inhibitor, UC2288, and development of a p21CIP1/WAF1-deficient cell line (Jurkatp21−) using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 gene editing. UC2288 blocked toxin-induced increases in p21CIP1/WAF1, and JurkatWT cells treated with this inhibitor exhibited reduced susceptibility to Cdt-induced apoptosis. Likewise, Jurkatp21− cells failed to undergo toxin-induced apoptosis. The linkage between Cdt, p21CIP1/WAF1, and apoptosis was further established by demonstrating that Cdt-induced increases in levels of the pro-apoptotic proteins Bid, Bax, and Bak were dependent upon p21CIP1/WAF1 as these changes were not observed in Jurkatp21− cells. Finally, we determined that the p21CIP1/WAF1 increases were dependent upon toxin-induced increases in the level and activity of the chaperone heat shock protein (HSP) 90. We propose that p21CIP1/WAF1 plays a key pro-apoptotic role in mediating Cdt-induced toxicity.

p21WAF1/Cip1 Regulation by hYSK1 Activates SP-1 Transcription Factor and Increases MMP-2 Expression under Hypoxic Conditions

The hYSK1, a serine/threonine kinase (STK)-25, has been implicated in a variety of cellular functions including cell migration and polarity. We have recently reported that hYSK1 down-regulated the expression and functions of p16INK4a, a cell cycle regulatory protein, thereby enhancing migration and growth of cancer cells under hypoxic conditions. In this study, we further investigated the mechanisms underlying downregulation of p16INK4a and anti-migratory function of hYSK1. Our study revealed that p21WAF1/Cip1 is a novel binding partner of hYSK1. Moreover, the interaction between hYSK1 and p21WAF1/Cip1 led to the inhibition of SP-1 transcriptional activity, as revealed by a significant down-regulation of SP-1-mediated transactivation of p16INK4a promoter, and accelerated MMP-2 expression. Conversely, the knock-down of hYSK1 enhanced the p16INK4a promoter activity and protein expression, and diminished MMP-2 transcription and protein levels in hypoxic conditions as compared to control. Taken together, hYSK1 blocks the p21WAF1/Cip1 functions by direct interaction and inhibits the p16INK4a expression and induces MMP-2 expression by its regulations of SP-1 transcriptional activity under the hypoxia conditions.

The role of cell cycle regulatory protein p53 in Follicular neoplasms of thyroid with hurthle cells

<p class="abstract"><strong><span lang="EN-US">Background:</span></strong><span lang="EN-US"> The disease biology of Follicular neoplasms of thyroid with hurthle cells is poorly understood. Very few studies in literature have addressed the role of p53 in these neoplasms. The aim of the present study is to analyze the histomorphological features of Follicular neoplasms with hurthle cell change and to evaluate the role of p53 in their tumor biology.</span></p><p class="abstract"><strong><span lang="EN-US">Methods:</span></strong>32 cases of Follicular neoplasms of thyroid with focal and pure hurthle cell change over a period of 2.5 years were studied histologically and immunohistochemically using p53 antibody (Biogenex). They included 20 follicular adenomas with focal hurthle cells, 10 pure hurthle cell adenomas and 2 hurthle cell carcinomas.</p><p class="abstract"><strong><span lang="EN-US">Results:</span></strong><span lang="EN-US"> All cases showed nuclear p53 positivity in hurthle cells. Muller-Hocker et al criteria was used for frequency scoring. Out of the 32 cases, 12 cases of pure hurthle cells showed score 3, Remaining 20 cases of follicular adenomas with focal hurthle cell change showed score 3 in cases with &gt;50% hurthle cells, score 2 in cases with 20-40% hurthle cells and score 0 in cases with &lt;10% hurthle cells.</span></p><p class="abstract"><strong><span lang="EN-US">Conclusions:</span></strong>The study showed a good correlation of p53 protein expression with tumor progression and aggressiveness. Hence this indicates that molecular alterations in p53 pathway play a role in tumor biology in Follicular neoplasms of thyroid with hurthle cell change.</p>