Reprogramming epigenetic silencing: artificial transcription factors synergize with chromatin remodeling drugs to reactivate the tumor suppressor <i>mammary serine protease inhibitor</i>

Beltran, Adriana S.; Sun, Xueqing; Lizardi, Paul M.; Blancafort, Pilar

doi:10.1158/1535-7163.mct-07-0526

Cited by 61 publications

(54 citation statements)

References 51 publications

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“…We demonstrated that epigenetic modifications through methylation play a critical role in the induction of CXCL4L1 in tumor cells similar to what has been reported for some other angiogenic factors, receptors, or chemokines, such as maspin (24), intercellular adhesion molecule-1 (ICAM-1) (25), or CXCL12 (SDF1; refs. 26,27).…”

Section: Discussionsupporting

confidence: 83%

Dual Roles for CXCL4 Chemokines and CXCR3 in Angiogenesis and Invasion of Pancreatic Cancer

et al. 2016

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The CXCL4 paralog CXCL4L1 is a less studied chemokine that has been suggested to exert an antiangiogenic function. However, CXCL4L1 is also expressed in patient tumors, tumor cell lines, and murine xenografts, prompting a more detailed analysis of its role in cancer pathogenesis. We used genetic and antibody-based approaches to attenuate CXCL4L1 in models of pancreatic ductal adenocarcinoma (PDAC). Mechanisms of expression were assessed in cell coculture experiments, murine, and avian xenotransplants, including through an evaluation of CpG methylation and mutation of critical CpG residues. CXCL4L1 gene expression was increased greatly in primary and metastatic PDAC. We found that myofibroblasts triggered cues in the tumor microenvironment, which led to induction of CXCL4L1 in tumor cells. CXCL4L1 expression was also controlled by epigenetic modifications at critical CpG islands, which were mapped. CXCL4L1 inhibited angiogenesis but also affected tumor development more directly, depending on the tumor cell type. In vivo administration of an mAb against CXCL4L1 demonstrated a blockade in the growth of tumors positive for CXCR3, a critical receptor for CXCL4 ligands. Our findings define a protumorigenic role in PDAC development for endogenous CXCL4L1, which is independent of its antiangiogenic function.

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Section: Discussionsupporting

confidence: 83%

Dual Roles for CXCL4 Chemokines and CXCR3 in Angiogenesis and Invasion of Pancreatic Cancer

et al. 2016

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“…A synergic effect of the inhibitor of DNA methylation on ATF to reactivate maspin was reported recently (Beltran et al, 2008;Beltran and Blancafort, 2011). In the present study, we also found that the transient transfection of p16ATF-6I significantly increased the transcription level of p16 in the H1299 and AGS cells pretreated with DNA methylation inhibitor DAC at nontoxic concentration (20-80 nM), which is much lower than the regularly used concentration (500-5,000 nM) to reactivate methylated genes or damage DNMT1 (Bender et al, 1998;Ghoshal et al, 2005).…”

Section: Discussionmentioning

confidence: 82%

The p16-Specific Reactivation and Inhibition of Cell Migration Through Demethylation of CpG Islands by Engineered Transcription Factors

et al. 2012

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Methylation of CpG islands inactivates transcription of tumor suppressor genes including p16 (CDKN2A). Inhibitors of DNA methylation and histone deacylation are recognized as useful cancer therapeutic chemicals through reactivation of the expression of methylated genes. However, these inhibitors are not target genespecific, so that they lead to serious side effects as regular cytotoxic chemotherapy agents. To explore the feasibility of methylated gene-specific reactivation by artificial transcription factors, we engineered a set of Sp1-like seven-finger zinc-finger proteins (7ZFPs) targeted to a 21-bp sequence of the p16 promoter and found that these 7ZFPs could bind specifically to the target p16 promoter probe. Then the p16-specific artificial transcription factors (p16ATFs) were made from these 7ZFPs and the transcription activator VP64. Results showed that transient transfection of some p16ATFs selectively up-regulated the endogenous p16 expression in the p16-active 293T cells. Moreover, the transient transfection of the representative p16ATF-6I specifically reactivated p16 expression in the p16-methylated H1299 and AGS cells pretreated with a nontoxic amount of 5'-azadeoxycytidine (20 and 80 nM, respectively). In addition, stable transfection of the p16ATF induced demethylation of p16 CpG island and trimethylation of histone H3K4, and inhibited recruitment of DNA methyltransferase 1 and trimethylation of H3K9 and H3K27 in the p16 promoter in H1299 cells without 5'-aza-deoxycytidine pretreatment. Notably, inhibition of cell migration and invasion was observed in these p16-reactivated cells induced by transient and stable p16ATF transfection. These results demonstrate that p16ATF not only specifically reactivates p16 expression through demethylation of CpG islands, but also restores methylated p16 function.

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“…Many approaches using designed ZFPs with activator domains were used to activate dormant genes (16,24). Recent activation of dormant tumor suppressor gene showed the inhibition of proliferation and invasion of tumor cell line (35,36). We expect that the attachment of an activator domain to our ZFP-TF targeting the hTERT promoter region could also lead to interesting results, as telomerase activity and telomere lengths are closely related to cell aging.…”

Section: Discussionmentioning

confidence: 99%

Repression of Human Telomerase Reverse Transcriptase Using Artificial Zinc Finger Transcription Factors

Sohn

Yeh

Choi

et al. 2010

Molecular Cancer Research

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Telomerase activation is a key step in the development of human cancers. Expression of the catalytic subunit, human telomerase reverse transcriptase (hTERT), represents the limiting factor for telomerase activity. In this study, we have used artificial zinc finger protein (ZFP) transcription factors (TF) to repress the expression of hTERT in human cancer cell lines at the transcriptional level. We have constructed four-fingered ZFPs derived from the human genome which binds 12-bp recognition sequences within the promoter of the hTERT gene and fused them with a KRAB repressor domain to create a potent transcriptional repressor. Luciferase activity was decreased by >80% in all of the transcriptional repressors with luciferase reporter assay. When they were transfected into the telomerase-positive HEK293 cell line, a decrease of mRNA level and telomerase activity together with shortening of telomere length was observed. Actual growth of HEK293 cells was also inhibited by transfection of artificial ZFP-TFs. The repression was maintained for 100 days of culture. The repression of telomerase expression by artificial ZFP-TFs targeting the promoter region of the hTERT presents a new promising strategy for inhibiting the growth of human cancer cells. Mol Cancer Res; 8(2); 246-53.

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Reprogramming epigenetic silencing: artificial transcription factors synergize with chromatin remodeling drugs to reactivate the tumor suppressor mammary serine protease inhibitor

Cited by 61 publications

References 51 publications

Dual Roles for CXCL4 Chemokines and CXCR3 in Angiogenesis and Invasion of Pancreatic Cancer

Dual Roles for CXCL4 Chemokines and CXCR3 in Angiogenesis and Invasion of Pancreatic Cancer

The p16-Specific Reactivation and Inhibition of Cell Migration Through Demethylation of CpG Islands by Engineered Transcription Factors

Repression of Human Telomerase Reverse Transcriptase Using Artificial Zinc Finger Transcription Factors

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