TAp73α Increases p53 Tumor Suppressor Activity in Thyroid Cancer Cells via the Inhibition of Mdm2-Mediated Degradation

2008 ◽  
Vol 6 (1) ◽  
pp. 64-77 ◽  
Author(s):  
Roberta Malaguarnera ◽  
Veronica Vella ◽  
Giuseppe Pandini ◽  
Mariangela Sanfilippo ◽  
Vincenzo Pezzino ◽  
...  
2011 ◽  
Vol 42 (01) ◽  
Author(s):  
P. Monfared ◽  
T. Viel ◽  
G. Schneider ◽  
Y. Waerzeggers ◽  
S. Rapic ◽  
...  

2014 ◽  
Vol 99 (7) ◽  
pp. E1163-E1172 ◽  
Author(s):  
Wei Qiang ◽  
Yuan Zhao ◽  
Qi Yang ◽  
Wei Liu ◽  
Haixia Guan ◽  
...  

Context: ZIC1 has been reported to be overexpressed and plays an oncogenic role in some brain tumors, whereas it is inactivated by promoter hypermethylation and acts as a tumor suppressor in gastric and colorectal cancers. However, until now, its biological role in thyroid cancer remains totally unknown. Objectives: The aim of this study is to explore the biological functions and related molecular mechanism of ZIC1 in thyroid carcinogenesis. Setting and Design: Quantitative RT-PCR (qRT-PCR) was performed to evaluate mRNA expression of investigated genes. Methylation-specific PCR was used to analyze promoter methylation of the ZIC1 gene. The functions of ectopic ZIC1 expression in thyroid cancer cells were determined by cell proliferation and colony formation, cell cycle and apoptosis, as well as cell migration and invasion assays. Results: ZIC1 was frequently down-regulated by promoter hypermethylation in both primary thyroid cancer tissues and thyroid cancer cell lines. Moreover, our data showed that ZIC1 hypermethylation was significantly associated with lymph node metastasis in patients with papillary thyroid cancer. Notably, restoration of ZIC1 expression in thyroid cancer cells dramatically inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrest and apoptosis by blocking the activities of the phosphatidylinositol-3-kinase (PI3K)/Akt and RAS/RAF/MEK/ERK (MAPK) pathways, and enhancing FOXO3a transcriptional activity. Conclusions: Our data demonstrate that ZIC1 is frequently inactivated by promoter hypermethyaltion and functions as a tumor suppressor in thyroid cancer through modulating PI3K/Akt and MAPK signaling pathways and transcription factor FOXO3a.


Author(s):  
Jayarani F. Putri ◽  
Priyanshu Bhargava ◽  
Jaspreet Kaur Dhanjal ◽  
Tomoko Yaguchi ◽  
Durai Sundar ◽  
...  

Abstract Background Mortalin is enriched in a large variety of cancers and has been shown to contribute to proliferation and migration of cancer cells in multiple ways. It has been shown to bind to p53 protein in cell cytoplasm and nucleus causing inactivation of its tumor suppressor activity in cancer cells. Several other activities of mortalin including mitochondrial biogenesis, ATP production, chaperoning, anti-apoptosis contribute to pro-proliferative and migration characteristics of cancer cells. Mortalin-compromised cancer cells have been shown to undergo apoptosis in in vitro and in vivo implying that it could be a potential target for cancer therapy. Methods We implemented a screening of a chemical library for compounds with potential to abrogate cancer cell specific mortalin-p53 interactions, and identified a new compound (named it as Mortaparib) that caused nuclear enrichment of p53 and shift in mortalin from perinuclear (typical of cancer cells) to pancytoplasmic (typical of normal cells). Biochemical and molecular assays were used to demonstrate the effect of Mortaparib on mortalin, p53 and PARP1 activities. Results Molecular homology search revealed that Mortaparib is a novel compound that showed strong cytotoxicity to ovarian, cervical and breast cancer cells. Bioinformatics analysis revealed that although Mortaparib could interact with mortalin, its binding with p53 interaction site was not stable. Instead, it caused transcriptional repression of mortalin leading to activation of p53 and growth arrest/apoptosis of cancer cells. By extensive computational and experimental analyses, we demonstrate that Mortaparib is a dual inhibitor of mortalin and PARP1. It targets mortalin, PARP1 and mortalin-PARP1 interactions leading to inactivation of PARP1 that triggers growth arrest/apoptosis signaling. Consistent with the role of mortalin and PARP1 in cancer cell migration, metastasis and angiogenesis, Mortaparib-treated cells showed inhibition of these phenotypes. In vivo tumor suppression assays showed that Mortaparib is a potent tumor suppressor small molecule and awaits clinical trials. Conclusion These findings report (i) the discovery of Mortaparib as a first dual inhibitor of mortalin and PARP1 (both frequently enriched in cancers), (ii) its molecular mechanism of action, and (iii) in vitro and in vivo tumor suppressor activity that emphasize its potential as an anticancer drug.


2013 ◽  
Vol 5 (4) ◽  
pp. 1143-1146 ◽  
Author(s):  
MIN FAN ◽  
XINYING LI ◽  
WEI JIANG ◽  
YUN HUANG ◽  
JINGDONG LI ◽  
...  

2018 ◽  
Vol 475 (12) ◽  
pp. 2057-2071 ◽  
Author(s):  
Selina Bäder ◽  
Elina Glaubke ◽  
Saskia Grüb ◽  
Stefanie Muhs ◽  
Jasmin Wellbrock ◽  
...  

Inositol-1,4,5-trisphosphate 3-kinase-A (ITPKA) exhibits oncogenic activity in lung cancer cells by regulating Ins(1,4,5)P3-mediated calcium release and cytoskeletal dynamics. Since, in normal cells, ITPKA is mainly expressed in the brain, it is an excellent target for selected therapy of lung cancer. However, ITPKB is strongly expressed in normal lung tissues, but is down-regulated in lung cancer cells by miR-375, assuming that ITPKB might have tumor suppressor activity. In addition, ITPKB binds to F-actin making it likely that, similar to ITPKA, it controls actin dynamics. Thus, the treatment of ITPKA-expressing lung cancer with ITPKA inhibitors simultaneously inhibiting ITPKB may counteract the therapy. Based on these considerations, we analyzed if ITPKB controls actin dynamics and if the protein reduces aggressive progression of lung cancer cells. We found that ITPKB bundled F-actin in cell-free systems. However, the stable expression of ITPKB in H1299 lung cancer cells, exhibiting very low endogenous ITPKB expression, had no significant effect on the actin structure. In addition, our data show that ITPKB negatively controls transmigration of H1299 cells in vitro by blocking Ins(1,4,5)P3-mediated calcium release. On the other hand, colony formation was stimulated by ITPKB, independent of Ins(1,4,5)P3-mediated calcium signals. However, dissemination of H1299 cells from the skin to the lung in NOD scid gamma mice was not significantly affected by ITPKB expression. In summary, ITPKB does not affect the cellular actin structure and does not suppress dissemination of human lung cancer cells in mice. Thus, our initial hypotheses that ITPKB exhibits tumor suppressor activity could not be supported.


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