rapid-isolation-viable-circulating-tumor-cells-from-patient-blood

Rapid Isolation of Viable Circulating Tumor Cells from Patient Blood Samples

Circulating tumor cells (CTC) are cells that disseminate from a primary tumor throughout the circulatory system and that can ultimately form secondary ...

Tachpyridine (N,N',N"-tris(2-pyridylmethyl)-cis,cis-1,3,5-triaminocyclohexane; tachpyr) is a potent hexadentate iron chelator under preclinical investigation as a potential anti-cancer agent. Tachpyridine induces apoptosis in cultured cancer cells by triggering a mitochondrial pathway of cell death that is p53-independent. To explore the relationship between the chelation chemistry of tachpyridine and its biological activity, a sensitive and specific reversed-phase high-performance liquid chromatography (RP-HPLC) method was devised and used to measure tachpyr and its metal complexes in cells and tissue culture media. Major species identified in cells treated with tachpyr were tachpyr itself, [Zn(tachpyr)](2+), and iron coordinated to two partially oxidized species of tachpyridine, [Fe(tachpyr-ox-2)](2+), and [Fe(tachpyr-ox-4)](2+). The kinetics of intracellular accumulation of [Zn(tachpyr)](2+) and [Fe(tachpyr-ox-2)](2+) were markedly different: [Zn(tachpyr)](2+) rapidly reached plateau levels, whereas intracellular levels of [Fe(tachpyr-ox-2)](2+) and free tachpyr rose steadily. At the last timepoint measured, 9% of total cellular iron and 13% of total cellular zinc were bound by tachpyridine. Taken together, [Zn(tachpyr)](2+), [Fe(tachpyr-ox-2)](2+), and free tachpyr accounted for virtually all of the tachpyr added, indicating that iron and zinc are the principal metals targeted by tachpyridine in cells. Consistent with these findings, activation of the apoptotic caspases 9 and 3 was blocked in cells pre-treated with either iron or zinc. Pretreatment with either of these metals also completely protected cells from the cytotoxic effects of tachpyridine. These results demonstrate a link between metal depletion and chelator cytotoxicity, and suggest that intracellular chelation of zinc as well as iron may play a role in the cytotoxicity of tachpyridine.

Article	Year
The Journal of biological chemistry\| PubMed ID: 11980894	2002
Role of zinc and iron chelation in apoptosis mediated by tachpyridine, an anti-cancer iron chelator. Biochemical pharmacology\| PubMed ID: 15081867	2004
Current topics in medicinal chemistry\| PubMed ID: 15579100	2004
Cancer chemotherapy and pharmacology\| PubMed ID: 15789226	2005
Cancer research\| PubMed ID: 18172300	2008
Clinical chemistry\| PubMed ID: 22344286	2012

Bryan T. Greene

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