Dataset Information

Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells.

ABSTRACT: Macropinocytosis is a normal cellular process by which cells internalize extracellular fluids and nutrients from their environment and is one strategy that Ras-transformed pancreatic cancer cells use to increase uptake of amino acids to meet the needs of rapid growth. Paradoxically, in non-Ras transformed medulloblastoma brain tumors, we have shown that expression and activation of the receptor tyrosine kinase TrkA overactivates macropinocytosis, resulting in the catastrophic disintegration of the cell membrane and in tumor cell death. The molecular basis of this uncontrolled form of macropinocytosis has not been previously understood. Here, we demonstrate that the overactivation of macropinocytosis is caused by the simultaneous activation of two TrkA-mediated pathways: (i) inhibition of RhoB via phosphorylation at Ser(185) by casein kinase 1, which relieves actin stress fibers, and (ii) FRS2-scaffolded Src and H-Ras activation of RhoA, which stimulate actin reorganization and the formation of lamellipodia. Since catastrophic macropinocytosis results in brain tumor cell death, improved understanding of the mechanisms involved will facilitate future efforts to reprogram tumors, even those resistant to apoptosis, to die.

SUBMITTER: Li C

PROVIDER: S-EPMC5038151 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells.

Li Chunhui C MacDonald James I S JI Talebian Asghar A Leuenberger Jennifer J Seah Claudia C Pasternak Stephen H SH Michnick Stephen W SW Meakin Susan O SO

Molecular and cellular biology 20160926 20

Macropinocytosis is a normal cellular process by which cells internalize extracellular fluids and nutrients from their environment and is one strategy that Ras-transformed pancreatic cancer cells use to increase uptake of amino acids to meet the needs of rapid growth. Paradoxically, in non-Ras transformed medulloblastoma brain tumors, we have shown that expression and activation of the receptor tyrosine kinase TrkA overactivates macropinocytosis, resulting in the catastrophic disintegration of t ...[more]

PMID: 27503856

Similar Datasets

Project description:Iron is required as a cofactor for many critical cellular enzymes involved in energy metabolism and cell proliferation and is thus essential for all living cells. To facilitate the rapid replication, the neoplastic cells have significantly higher levels of ribonucleotide reductase and the transferrin receptor 1 (TfR1) and many in vitro and in vivo studies have demonstrated that, compared to normal cells, cancer cells are more sensitive to iron (Fe) deprivation because of their marked Fe requirements. The higher Fe utilization by cancer cells provides a rationale for the selective antitumor activity of chelators. To date, Deferoxamine (DFO) is one of the most widely used iron chelator. In addition, DFO also has some antitumor activity. Moreover, novel chelators based on the di-2-pyridylketone thiosemicarbazone (DpT) scaffold, such as di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), induce iron sequestration and also form redox-active metal complexes that demonstrate potent and selective anti-tumor activity. Notably, Dp44mT and its analogs possess broad anti-cancer and anti-metastatic activity in vitro and in vivo against a variety of aggressive solid tumors. Understanding the mechanism of action of these ligands and their effect on the ER stress pathway will yield better clinical outcomes. It has been reported that iron depletion induced by Dp44mT and its metal complexes causes apoptosis by generating cytotoxic ROS and by inducing DNA strand breaks. The redox active complexes formed in lysosomes induce damages generating tumor cell cytotoxicity. The alterations in gene expression after iron depletion are complex. Moreover, in cultured cells Dp44mT resulted in marked up-regulation of the Fe-responsive tumor growth and metastasis suppressor Ndrg1 (N-myc downstream regulated gene-1). Therefore, Up-regulation of Ndrg1 may be another mechanism by which chelators inhibit cancer cell proliferation. Here we combine biochemistry, microscopy, flow cytometry and LC/MS-MS analyses to investigate cellular events induced by DFO and Dp44mT iron chelators on two human breast cancer cell lines, MDA-MB-231 and MDA-MB-157, in terms of proliferation, cell cycle, cytotoxicity and death. These experiments could potentially provide additional information in terms of the mechanism(s) of action of iron chelators in breast cancer cells.

Dataset Information

Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells.

Publications

Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets