Survival Of Thyroid Carcinoma Cells Research Articles

Autophagy sustains mitochondrial respiration and determines resistance to BRAFV600E inhibition in thyroid carcinoma cells

ABSTRACT BRAFV600E is the most prevalent mutation in thyroid cancer and correlates with poor prognosis and therapy resistance. Although selective inhibitors of BRAFV600E have been developed, more advanced tumors such as anaplastic thyroid carcinomas show a poor response in clinical trials. Therefore, the study of alternative survival mechanisms is needed. Since metabolic changes have been related to malignant progression, in this work we explore metabolic dependencies of thyroid tumor cells to exploit them therapeutically. Our results show that respiration of thyroid carcinoma cells is highly dependent on fatty acid oxidation and, in turn, fatty acid mitochondrial availability is regulated through macroautophagy/autophagy. Furthermore, we show that both lysosomal inhibition and the knockout of the essential autophagy gene, ATG7, lead to enhanced lipolysis; although this effect is not essential for survival of thyroid carcinoma cells. We also demonstrate that following inhibition of either autophagy or fatty acid oxidation, thyroid tumor cells compensate oxidative phosphorylation deficiency with an increase in glycolysis. In contrast to lipolysis induction, upon autophagy inhibition, glycolytic boost in autophagy-deficient cells is essential for survival and, importantly, correlates with a higher sensitivity to the BRAFV600E selective inhibitor, vemurafenib. In agreement, downregulation of the glycolytic pathway results in enhanced mitochondrial respiration and vemurafenib resistance. Our work provides new insights into the role of autophagy in thyroid cancer metabolism and supports mitochondrial targeting in combination with vemurafenib to eliminate BRAFV600E-positive thyroid carcinoma cells. Abbreviations: AMP: adenosine monophosphate; ATC: anaplastic thyroid carcinoma; ATG: autophagy related; ATP: adenosine triphosphate; BRAF: B-Raf proto-oncogene, serine/threonine kinase; Cas9: CRISPR-associated protein; CREB: cAMP responsive element binding protein; CRISPR: clustered regularly interspaced short palindromic repeats; 2DG: 2-deoxyglucose; FA: fatty acid; FAO: fatty acid oxidation; FASN: fatty acid synthase; FCCP: trifluoromethoxy carbonyl cyanide phenylhydrazone; LAMP1: lysosomal associated membrane protein 1; LIPE/HSL: lipase E, hormone sensitive type; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; OCR: oxygen consumption rate; OXPHOS: oxidative phosphorylation; PRKA/PKA: protein kinase cAMP-activated; PTC: papillary thyroid carcinoma; SREBF1/SREBP1: sterol regulatory element binding transcription factor 1.

MON-516 Quantitative Analysis of Differential Enigma/PDLIM7 Gene Expression in Thyroid Cancer vs. Benign Nodules

Thyroid cancer incidence is rising worldwide. Although fine-needle aspiration biopsy (FNAB) is an accurate modality for evaluating thyroid nodules, up to 25% of FNABs still yield indeterminate results. There is a considerable number of diagnostic thyroidectomies for benign disease as a result of indeterminate FNAB. A more accurate and time-efficient diagnostic approach for analyzing indeterminate thyroid nodules may reduce diagnostic thyroidectomy. Recently, the osteogenic protein, Enigma, has been associated with different cancer types, including thyroid cancer progression and calcification through its interaction with bone morphogenic protein-1 (BMP-1), and tyrosine kinases linked to mitogenic signaling pathways [1, 2]. Our published data on Enigma protein analysis with immunohistochemistry showed promising results in discriminating between malignant versus benign thyroid nodules and demonstrated a correlation with thyroid cancer staging [3]. In this study, we are investigating Enigma at a gene expression level by real-time (RT-qPCR), which is a quantitative and more time-efficient method that requires smaller samples (FNA) than immunohistochemistry. We analyzed Enigma mRNA expression levels to determine if Enigma-qPCR could be used as a diagnostic tool to improve the accuracy of FNAB in both malignant and benign thyroid tissues. We extracted mRNA/DNA/proteins from fresh malignant and benign thyroid nodules using a QIAGEN DNA/RNA/Protein Kit. We ran isolated pure mRNA through Enigma-qPCR. The results showed that the Enigma-mRNA expression was 3-fold higher in malignant as compared to benign thyroid tissues. This finding supports our previous Enigma immunohistochemistry data and shows a relative quantitative difference in Enigma-mRNA expression level between malignant and benign thyroid nodules. We conclude that Enigma-RT-qPCR can be used to effectively determine malignancies in FNAB samples derived from thyroid nodules. This method could potentially enhance the diagnostic accuracy of indeterminate nodules and decrease diagnostic thyroidectomies and associated morbidity.[1] C.R. Jung, J.H. Lim, Y. Choi, D.G. Kim, K.J. Kang, S.M. Noh, D.S. Im, Enigma negatively regulates p53 through MDM2 and promotes tumor cell survival in mice, The Journal of clinical investigation 120(12) (2010) 4493-506.[2] Y.J. Kim, H.J. Hwang, J.G. Kang, C.S. Kim, S.H. Ihm, M.G. Choi, S.J. Lee, Enigma Plays Roles in Survival of Thyroid Carcinoma Cells through PI3K/AKT Signaling and Survivin, Anticancer research 38(6) (2018) 3515-3525.[3] A.A. Firek, M.C. Perez, A. Gonda, L. Lei, I. Munir, A.A. Simental, F.E. Carr, B.J. Becerra, M. De Leon, S. Khan, Pathologic significance of a novel oncoprotein in thyroid cancer progression, Head & neck 39(12) (2017) 2459-2469.

Evodiamine in combination with histone deacetylase inhibitors has synergistic cytotoxicity in thyroid carcinoma cells.

The impact of evodiamine in combination with histone deacetylase (HDAC) inhibitors on survival of thyroid carcinoma cells was identified. TPC-1 and SW1736 human thyroid carcinoma cells were used. After treatment with evodiamine and PXD101, cell viability, the percentage of viable cells and Bcl2 protein levels decreased, whereas cytotoxic activity, the percentage of apoptotic cells, the protein levels of γH2AX, acetyl. histone H3 and cleaved PARP, and reactive oxygen species (ROS) production increased. In cells treated with both evodiamine and PXD101, compared with PXD101 alone, decrement of cell viability, the percentage of viable cells, and Bcl2 protein levels as well as increment of cytotoxic activity, the percentage of apoptotic cells, the protein levels of γH2AX and cleaved PARP, and ROS production were significant, causing decrement of Bcl2/Bax ratio. Furthermore, all of the combination index values were <1.0, suggesting synergistic cytotoxicity of two agents. Wortmannin decreased cell viability and the percentage of viable cells, whereas it increased cytotoxic activity and the percentage of apoptotic cells without alteration in ROS production. The changes in cells treated with both evodiamine and suberoylanilide hydroxamic acid or trichostatin A were similar to those in cells treated with both evodiamine and PXD101. Our results demonstrate that evodiamine synergizes with HDAC inhibitors in inducing cytotoxic activities by involving survival-related proteins and ROS in thyroid carcinoma cells. Moreover, repression of PI3K/Akt signaling synergistically reinforces cytotoxicity of evodiamine combined with HDAC inhibitors in thyroid carcinoma cells.

Enigma Plays Roles in Survival of Thyroid Carcinoma Cells through PI3K/AKT Signaling and Survivin.

The aim of the present study was to assess the role of enigma protein in survival of thyroid carcinoma cells. BCPAP and 8505C human thyroid carcinoma cells were used. Cell viability using CCK-8 assay, the percentage of dead cells using trypan blue assay, cytotoxic activity using cytotoxicity assay, cell growth rate and cell migration using wound-healing assay were performed. In enigma siRNA-transfected cells, cell viability, and the protein levels of AKT and survivin decreased. The percentage of dead cells, cytotoxic activity and cleaved poly (ADP-ribose) polymerase (PARP) protein levels increased. After transfection of p110α plasmid, the alterations in cell viability, the percentage of dead cells, cytotoxic activity, and protein levels of AKT, survivin and cleaved PARP were abrogated. Cell growth rate and cell migration were reduced with reduction of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) protein levels, as well as increased p53 and p21 protein levels. Enigma affects cell survival through modulation of phosphatidylinositol-3 kinase/AKT signaling and survivin, and regulates cell proliferation and migration via involvement of MMP-2, MMP-9, p53 and p21 in thyroid carcinoma cells.

Gemigliptin, a novel dipeptidyl peptidase-IV inhibitor, exerts a synergistic cytotoxicity with the histone deacetylase inhibitor PXD101 in thyroid carcinoma cells.

The influence of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the histone deacetylase inhibitor PXD101 on survival of thyroid carcinoma cells was investigated. SW1736, TPC-1, 8505C and BCPAP human thyroid carcinoma cells were used. To assess cell survival, cell viability, the percentage of viable cells and dead cells, cytotoxic activity, ATP levels and FACS analysis were measured. To validate the impact of gemigliptin combined with PXD101, the interactions were estimated by obtaining combination index in cells treated with two agents. In cells treated with gemigliptin or PXD101, cell viability, the percentage of viable cells and ATP levels were reduced, and the percentage of dead cells and cytotoxic activity were elevated. In cells treated with both gemigliptin and PXD101, compared with PXD101 alone, cell death was augmented, and all of the combination index values were lower than 1.0, suggesting the synergism between gemigliptin and PXD101. The percentage of apoptotic cells, and the protein levels of Bcl2 and cleaved poly (ADP-ribose) polymerase were elevated, and the protein levels of xIAP and survivin were reduced. The protein levels of phospho-Akt and phospho-AMPK were elevated, and cell migration was reduced. Our results demonstrate that gemigliptin induces cytotoxicity in thyroid carcinoma cells. Moreover, gemigliptin has a synergistic activity with PXD101 in the induction of cell death through involvement of Bcl2 family proteins, xIAP and survivin as well as mediation of Akt and AMPK in thyroid carcinoma cells.

The dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with NVP-AUY922 has a cytotoxic activity in thyroid carcinoma cells.

The effect of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the heat shock protein 90 inhibitor NVP-AUY922 (AUY922) on survival of thyroid carcinoma cells was elucidated. The SW1736 and TPC-1 human thyroid carcinoma cells were used. Cell viability, the percentage of viable cells, cytotoxic activity, the percentage of apoptotic cells, and mitochondrial membrane potential were measured. To evaluate the combined effect of gemigliptin with AUY922, the interactions were estimated by calculating combination index. Gemigliptin led to cell death in conjunction with overexpression of the phosphorylated protein levels of Akt, extracellular signal-regulated kinase 1/2, and adenosine monophosphate-activated protein kinase. In gemigliptin-treated cells, wortmannin augmented cell death, whereas AZD6244 and compound C did not affect cell survival. Wortmannin decreased phosphorylated adenosine monophosphate-activated protein kinase protein levels, and AZD6244 increased phosphorylated Akt protein levels. Meanwhile, cotreatment of both gemigliptin and AUY922, compared with treatment of AUY922 alone, potentiated cell death. All the combination index values were lower than 1.0, suggesting synergistic cytotoxicity of gemigliptin with AUY922. In treatment of both gemigliptin and AUY922, compared with AUY922 alone, the protein levels of total and phosphorylated Akt, phosphorylated extracellular signal-regulated kinase 1/2, and phosphorylated adenosine monophosphate-activated protein kinase increased without alteration in those of total extracellular signal-regulated kinase 1/2 and total adenosine monophosphate-activated protein kinase. The percentage of apoptotic cells increased. The protein levels of Bax and cleaved poly (ADP-ribose) polymerase increased, whereas Bcl2 protein levels were unchanged, resulting in increment of Bax/Bcl2 ratio. Transfection of Bax small interfering RNA did not cause any variation in cell viability, the percentage of viable cells and cytotoxic activity. Our results demonstrate that gemigliptin exerts a cytotoxic activity with concomitant alterations in expression of Akt, extracellular signal-regulated kinase 1/2, and adenosine monophosphate-activated protein kinase in thyroid carcinoma cells. Furthermore, gemigliptin synergizes with AUY922 in induction of cytotoxicity via regulation of Akt, extracellular signal-regulated kinase 1/2, and adenosine monophosphate-activated protein kinase as well as involvement of Bcl2 family proteins in thyroid carcinoma cells.

Synergistic cytotoxicity of BIIB021 with triptolide through suppression of PI3K/Akt/mTOR and NF-κB signal pathways in thyroid carcinoma cells.

The effec.t of BIIB021, a novel heat shock protein 90 (hsp90) inhibitor, on survival of thyroid carcinoma cells has not been evaluated. In this study, the impact of BIIB021 alone or in combination with the histone acetyltransferase inhibitor triptolide on survival of thyroid carcinoma cells was identified. In 8505C and TPC-1 thyroid carcinoma cells, BIIB021 caused cell death in conjunction with alterations in expression of hsp90 client proteins. Cotreatment of both BIIB021 and triptolide, compared with treatment of BIIB021 alone, decreased cell viability, and increased the percentage of dead cells and cytotoxic activity. All of the combination index values were lower than 1.0, suggesting synergistic activity of BIIB021 with triptolide in induction of cytotoxicity. In treatment of both BIIB021 and triptolide, compared with treatment of BIIB021 alone, the protein levels of total and phospho-p53, and cleaved caspase-3 were elevated, while those of total Akt, phospho-mTOR, phospho-4EBP1, phospho-S6K, phospho-NF-κB, survivin, X-linked inhibitor of apoptosis protein (xIAP), cellular inhibitor of apoptosis protein (cIAP) and acetyl. histone H4 were reduced. These results suggest that BIIB021 has a cytotoxic activity accompanied by regulation of hsp90 client proteins in thyroid carcinoma cells. Moreover, the synergism between BIIB021 and triptolide in induction of cytotoxicity is associated with the inhibition of PI3K/Akt/mTOR and NF-κB signal pathways, the underexpression of survivin and the activation of DNA damage response in thyroid carcinoma cells.