Down-regulation of hTERT and Cyclin D1 transcription via PI3K/Akt and TGF-β pathways in MCF-7 Cancer cells with PX-866 and Raloxifene

Peek, Gregory W.; Tollefsbol, Trygve O.

doi:10.1016/j.yexcr.2016.03.022

Cited by 13 publications

(10 citation statements)

References 73 publications

(91 reference statements)

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“…Its activation seems to be more frequent in thyroid cancer types with poor differentiation, suggesting that telomerase activation may contribute to (or be associated with) more aggressive behavior of thyroid cancer [43]. Given the regulation of hTERT expression by p53 and other mechanisms [44, 45], we further examined the synergistic effect of p53 reactivation and PI3K/Akt pathway inhibition on hTERT expression. Our results not only showed that BKM120 and Prima-1 Met synergistically down-regulated hTERT promoter activity and its expression, but also demonstrated such down-regulation was mediated by decreased CFSF4 expression and its binding to the promoter region of hTERT.…”

Section: Discussionmentioning

confidence: 99%

Synergistic Antitumor Effect of BKM120 with Prima-1Met Via Inhibiting PI3K/AKT/mTOR and CPSF4/hTERT Signaling and Reactivating Mutant P53

Xu²,

Li³

et al. 2018

Cell Physiol Biochem

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Background/Aims: PI3KCA and mutant p53 are associated with tumorigenesis and the development of cancers. NVP-BKM120, a selective pan-PI3K inhibitor, exerts the antitumor activity by suppressing the PI3K signaling pathway. Prima-1^Met, a low molecular weight compound, can rescue the gain-of-function of mutant p53 by restoring its transcriptional function. In this study, we investigated whether PI3K inhibition combined with mutant p53 reactivation could enhance the antitumor effect in thyroid cancer cells. Methods: The effects of BKM120 and Prima-1^Met on the proliferation, apoptosis, migration and invasion of thyroid cancer cells were measured by MTT, colony formation, flow cytometry, wound-healing and transwell assays, respectively. Thyroid differentiation was assessed by detecting the expression levels of specific markers using RT-PCR and Western blot. The in vivo antitumor efficacy was analyzed in a mouse xenograft model. Results: The combinational treatment of BKM120 and Prima-1^Met significantly enhanced the inhibitions of cell viability, colony formation, migration and invasion, and the induction of apoptosis in thyroid cell lines, and synergistically suppressed tumor xenograft growth by inhibiting the PI3K/Akt/mTOR and EMT signaling pathways, up-regulating p53 targeted genes, and triggering the release of cytochrome c. Moreover, the combination of BKM120 and Prima-1^Met suppressed the stemlike traits of thyroid cancer cells and promoted their differentiation by upregulating the expression of thyroid-specific differentiation markers and repressing the expression of cancer stem cell markers. Furthermore, the mechanism study demonstrated that the combinational treatment synergistically abrogated the binding of CPSF4 at the promoter of hTERT and thus suppressed hTERT expression. Consistently, overexpression of hTERT rescued the inhibitions of cell viability, invasion and stem-like traits mediated by the combination of BKM120 and Prima-1^Met. Conclusion: Our results showed that the combination of BKM120 with Prima-1^Met synergistically suppressed the growth of thyroid cancer cells and tumor xenografts via inhibiting PI3K/Akt/mTOR and CPSF4/hTERT signaling and reactivating mutant p53.

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Section: Discussionmentioning

confidence: 99%

Synergistic Antitumor Effect of BKM120 with Prima-1Met Via Inhibiting PI3K/AKT/mTOR and CPSF4/hTERT Signaling and Reactivating Mutant P53

Xu²,

Li³

et al. 2018

Cell Physiol Biochem

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“…On the other hand, HKR3 inhibited the expression of hTERT and decreased telomere activity in early cancer [17]. Inhibition of hTERT has been reported to inhibit cyclin activity [26]. Therefore, the correlation between hTERT, HKR3 and cell cycle factors can be confirmed.…”

Section: Discussionmentioning

confidence: 88%

HKR3 regulates cell cycle through the inhibition of hTERT in hepatocellular carcinoma cell lines

Choi¹,

Cho²,

Yun³

et al. 2020

J. Cancer

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Hepatocellular carcinoma is a malignant disease with improved hepatic regeneration and survival, and is activated by human telomere transferase (hTERT). hTERT is expressed during early fetal development and switched off in most adult tissues, but it becomes reactivated in HCC. The exact mechanism regulating these expression changes remains unknown during HCC progress. We evaluated the relationship between hTERT expression and human kruppel-related 3 (HKR3) and cell cycle-related factors in HCC cell lines. Following transfection for hTERT knockdown and HKR3 overexpression, proteomic and transcriptomic analyses related to hTERT were performed using liquid chromatography/mass spectrometry (LC/MS) and RNA sequencing (RNAseq) in HCC cell lines. The expression levels of hTERT, HKR3, and cell cycle-related factors were measured using western blotting, and tumor growth were evaluated via cell proliferation and cell cycle assays. Transcriptomic and proteomic analyses showed that HKR3, hTERT and cyclin-dependent kinase inhibitor 2A (CDKN2A) were correlated. Up-regulation of HKR3 expression decreased hTERT and cyclin activation and suppressed the G1/S phase of the cell cycle through CDKN2A activation. Our results suggest that HKR3 induced regulation of cell cycle through hTERT inhibition and CDKN2A activation. Our results will facilitate further exploration of the pathways regulating human telomerase activity in HCC cell lines.

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“…Downregulation of PEA15 and survivin by EGCG has been shown to occur via reduced phosphorylation of Akt in U87 cells (53). In addition, downregulation of telomerase expression was also found to occur by suppression of phosphorylation of AKT (84). Moreover, GRP78 has been reported to be responsible for tamoxifen resistance in breast cancer which is regulated by phosphorylated AKT (85).…”

Section: ) Pea15mentioning

confidence: 97%

Effects of the Green Tea Polyphenol Epigallocatechin-3-Gallate on Glioma: A Critical Evaluation of the Literature

Leenders

Molenaar

et al. 2018

Nutrition and Cancer

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The review discusses the effects of Epigallocatechin-3-gallate Gallate (EGCG) on glioma as a basis for future research on clinical application of EGCG. Epidemiological studies on the effects of green tea or EGCG on the risk of glioma is inconclusive due to the limited number of studies, the inclusion of all tea types in these studies, and the focus on caffeine rather than EGCG. In vivo experiments using EGCG monotherapy are inconclusive. Nevertheless, EGCG induces cell death, prevents cellular proliferation, and limits invasion in multiple glioma cell lines. Furthermore, EGCG enhances the efficacy of anti-glioma therapies, including irradiation, temozolomide, carmustine, cisplatin, tamoxifen, and TNF-related apoptosis-inducing ligand, but reduces the effect of bortezomib. Pro-drugs, co-treatment, and encapsulation are being investigated to enhance clinical applicability of EGCG. Mechanisms of actions of EGCG have been partly elucidated. EGCG has both anti-oxidant and oxidant properties. EGCG inhibits pro-survival proteins, such as telomerase, survivin, GRP78, PEA15, and P-gp. EGCG inhibits signaling of PDGFR, IGF-1R, and 67LR. EGCG reduces invasiveness of cancer cells by inhibiting the activities of various metalloproteinases, cytokines, and chemokines. Last, EGCG inhibits some NADPH-producing enzymes, thus disturbing redox status and metabolism of glioma cells. In conclusion, EGCG may be a suitable adjuvant to potentiate anti-glioma therapies.

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Down-regulation of hTERT and Cyclin D1 transcription via PI3K/Akt and TGF-β pathways in MCF-7 Cancer cells with PX-866 and Raloxifene

Cited by 13 publications

References 73 publications

Synergistic Antitumor Effect of BKM120 with Prima-1Met Via Inhibiting PI3K/AKT/mTOR and CPSF4/hTERT Signaling and Reactivating Mutant P53

Synergistic Antitumor Effect of BKM120 with Prima-1Met Via Inhibiting PI3K/AKT/mTOR and CPSF4/hTERT Signaling and Reactivating Mutant P53

HKR3 regulates cell cycle through the inhibition of hTERT in hepatocellular carcinoma cell lines

Effects of the Green Tea Polyphenol Epigallocatechin-3-Gallate on Glioma: A Critical Evaluation of the Literature

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