The use of transformed IMR90 cell model to identify the potential extra-telomeric effects of hTERT in cell migration and DNA damage response.

Xu Cao,Chiou Mee Kong,Valere Cacheux-Rataboul,Kanchi Madhu Mathi,Xueying Wang,Yoon Pin Lim

doi:10.1186/1471-2091-15-17

Xu Cao, Chiou Mee Kong + Show 4 more

Open Access

https://doi.org/10.1186/1471-2091-15-17

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Abstract

BackgroundHuman telomerase reverse transcriptase (hTERT), the catalytic subunit of telomesase, is responsible for telomere maintenance and its reactivation is implicated in almost 90% human cancers. Recent evidences show that hTERT is essential for neoplastic transformation independent of its canonical function. However, the roles of hTERT in the process remain elusive. In the current work, we explore the extra-telomeric role of hTERT in the neoplastic transformation of fibroblast IMR90.ResultsHere we established transformed IMR90 cells by co-expression of three oncogenic factors, namely, H-Ras, SV40 Large-T antigen and hTERT (RSH). The RSH-transformed cells acquired hallmarks of cancer, such as they can grow under anchorage independent conditions; self-sufficient in growth signals; attenuated response to apoptosis; and possessed recurrent chromosomal abnormalities. Furthermore, the RSH-transformed cells showed enhanced migration capability which was also observed in IMR90 cells expressing hTERT alone, indicating that hTERT plays a role in cell migration, and thus possibly contribute to their metastatic potential during tumor transformation. This notion was further supported by our microarray analysis. In addition, we found that Ku70 were exclusively upregulated in both RSH-transformed IMR90 cells and hTERT-overexpressing IMR90 cells, suggesting the potential role of hTERT in DNA damage response (DDR).ConclusionsCollectively, our study revealed the extra-telomeric effects of hTERT in cell migration and DDR during neoplastic transformation.

Highlights

Human telomerase reverse transcriptase, the catalytic subunit of telomesase, is responsible for telomere maintenance and its reactivation is implicated in almost 90% human cancers
These findings suggest that Human telomerase reverse transcriptase (hTERT) plays a key role in tumorigenesis independent of its canonical function
RSH-transformed cells acquire cancer cells characteristics Primary human fibroblast cells IMR90 were successfully co-transfected with Ras, SV40 Large-T, and hTERT and their protein expressions were confirmed by western blotting (Figure 1A)

Summary

Introduction

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomesase, is responsible for telomere maintenance and its reactivation is implicated in almost 90% human cancers. Recent evidences show that hTERT is essential for neoplastic transformation independent of its canonical function. Emerging evidence suggests that maintenance of telomere length might not the sole function of hTERT during oncogenesis. Human cells utilize alternative lengthening of telomeres pathway for telomere maintenance can only be transformed when co-expressing hTERT and oncogenic-Ras, indicating that hTERT is indispensable for cancer transformation [11,12]. Taken together, these findings suggest that hTERT plays a key role in tumorigenesis independent of its canonical function. Investigating the roles of hTERT in the cancer transformation is of utmost imperative

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