Systematic Analysis of Compounds Specifically Targeting Telomeres and Telomerase for Clinical Implications in Cancer Therapy

Abstract

The targeting of telomerase and telomere maintenance mechanisms represents a promising therapeutic approach for various types of cancer. In this work, we designed a new protocol to screen for and rank the efficacy of compounds specifically targeting telomeres and telomerase. This approach used two isogenic cell lines containing a circular human artificial chromosome (HAC, lacking telomeres) and a linear HAC (containing telomeres) marked with the transgene; compounds that target telomerase or telomeres should preferentially induce loss of the linear HAC but not the circular HAC. Our assay allowed quantification of chromosome loss by routine flow cytometry. We applied this dual-HAC assay to rank a set of known and newly developed compounds, including G-quadruplex (G4) ligands. Among the latter group, two compounds, Cu-ttpy and Pt-ttpy, induced a high rate of linear HAC loss with no significant effect on the mitotic stability of a circular HAC. Analysis of the mitotic phenotypes induced by these drugs revealed an elevated rate of chromatin bridges in late mitosis and cytokinesis as well as UFB (ultrafine bridges). Chromosome loss after Pt-ttpy or Cu-ttpy treatment correlated with the induction of telomere-associated DNA damage. Overall, this platform enables identification and ranking of compounds that greatly increase chromosome mis-segregation rates as a result of telomere dysfunction and may expedite the development of new therapeutic strategies for cancer treatment. An assay provides a unique opportunity to screen thousands of chemical compounds for their ability to inactivate replication of telomeric ends in cancer cells and holds potential to lay the foundation for the discovery of new treatments for cancer. .

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

“…Most notably, it has been shown that quadruplex formation is directly involved in biologically relevant processes [10], for example, in the suppression of gene expression [11,12] or the induction of the cellular response to DNA damage [13,14]. Because of the increasing evidence of an essential biological function of G4-DNA, this DNA form is considered as an attractive target in drug development [1,2,15,16]. For that purpose, G4-DNAtargeting ligands are searched for that bind selectively and sufficiently strong to quadruplex DNA and thereby influence the biological function of G-rich DNA sequences [17][18][19][20][21][22].…”

Ratiometric Electrochemical Sensing Strategy for the Ultrasensitive Detection of Telomerase Activity

“…Human telomerase is a ribonucleoprotein complex with an endogenous RNA template, which catalyzes the extension of hexamer DNA repeats . In a majority of human cancers, telomerase is upregulated or reactivated, which leads to indefinite proliferation of cancer cells .…”

A robust photoluminescence screening assay identifies uracil-DNA glycosylase inhibitors against prostate cancer

“…2.5 fold) in the co-treated group compared with only the 5-FU treated group (Fig. S9A †), and an increasing accumulation of Ser139-phosphorylated g-H 2 AX and cleaved-PARP in the combination group over 0, 4,8,12,16, and 20 h of treatment (Fig. S9B †), suggesting that A8 could enhance the ability of 5-FU to induce DNA damage.…”

“…1,2 Prostate cancer ranks second among cancers in incidence among men, with 1 million new incidences of cancer reported every year. 3 Radiotherapy, which involves using high frequency waves to destroy tumor cells, 4 is commonly employed for prostate cancer treatment. 5 However, radiotherapy exhibits certain adverse effects, including loss of appetite, vomiting, nausea, hair loss and sore skin.…”