The mTOR Kinase Inhibitor CZ415 Inhibits Human Papillary Thyroid Carcinoma Cell Growth

Abstract

Background/Aim: Mammalian target of rapamycin (mTOR) plays an important role in papillary thyroid carcinoma (PTC) cell progression. CZ415 is a novel, highly-efficient and specific mTOR kinase inhibitor. The current study tested the potential anti-tumor activity of CZ415 in human PTC cells. Methods: The established (TPC-1 cell line) and primary human PTC cells were treated with CZ415. Cell survival and growth were tested by Cell Counting Kit-8 assay and BrdU ELISA assay, respectively. Cell apoptosis was tested by caspase-3/-9 activity assay, Hoechst-33342 staining assay and single-stranded DNA ELISA assay. Cell cycle progression was tested by propidium iodide-FACS assay. The mTOR signaling was tested by Western blotting assay and co-immunoprecipitation assay. The mouse xenograft tumor model was applied to study the effect of CZ415 in vivo. Results: In cultured human PTC cells, treatment with CZ415 at nM concentrations significantly inhibited cell survival and growth. CZ415 induced apoptosis activation and cell cycle arrest in human PTC cells. CZ415 disrupted assembling of mTORC1 (mTOR-Raptor association) and mTORC2 (mTOR-Rictor-GβL association) in TPC-1 cells, which led to de-phosphorylation of the mTORC1 substrates (S6K1 and 4E-BP1) and the mTORC2 substrate AKT (Ser-473). Further studies show that the autophagy inhibitor 3-methyladenine (3-MA) or Beclin-1 shRNA aggravated CZ415-induced cytotoxicity against PTC cells. In vivo, CZ415 oral administration inhibited TPC-1 xenograft tumor growth in mice. Conclusion: Our results show that mTOR blockage by CZ415 inhibits PTC cell growth in vitro and in vivo.

<p>Autophagy-Related Beclin 1 and Head and Neck Cancers</p>

“…In thyroid carcinomas, inhibition of autophagy by Beclin 1 siRNA or 3-MA increased the sensitivity of TPC-1 cells to CZ415. 123 …”

“…In thyroid carcinomas, inhibition of autophagy by Beclin 1 siRNA or 3-MA increased the sensitivity of TPC-1 cells to CZ415. 123 Inhibition of Beclin 1 may increase the antitumor effect obtained by suppressing long non-coding RNA (lncRNA). The lncRNA HOX transcript antisense RNA (lncRNA HOTAIR), which is localized in the endonuclear region, is a functional RNA molecule that contains more than 200 nucleotides and is upregulated in many cancers.…”

Exogenous Hydrogen Sulfide Regulates the Growth of Human Thyroid Carcinoma Cells

“…However, whether H 2 S is involved in the growth of human thyroid carcinoma cells remains unknown. Human thyroid carcinoma cell lines TPC-1, TT, and ARO cells have been widely implicated in establishing tumor-bearing animal models [44–46]. In this study, TPC-1, TT, and ARO cells were used to evaluate the effects of exogenous H 2 S both in vitro and in vivo .…”

“…TPC-1, TT, and ARO cells have been widely adopted to establish subcutaneous xenograft models [44–46]. We therefore examined the effect of exogenous H 2 S on the growth of human thyroid carcinoma xenograft tumors in BALB/c nude mice.…”

Long non‐coding RNA TNRC6C‐AS1 promotes methylation of STK4 to inhibit thyroid carcinoma cell apoptosis and autophagy via Hippo signalling pathway

“…20 TC is a major health threat to human beings all over the world. 21 Meanwhile, a new study has showed the influence of lncRNA TNRC6C-AS1 on proliferation, apoptosis and invasion of papillary TC cells. 8 In this study, we explored the role of the lncRNA TNRC6C-AS1, STK4…”