Selective inhibition of V600E-mutant BRAF gene induces apoptosis in thyroid carcinoma cell lines

Kyoung Sik Park; Madhuri Saindane; Eun Yeol Yang; TongYi Jin; Harikrishna Reddy Rallabandi; Alexander Heil; Sang Eun Nam; Young Bum Yoo; Jung-Hyun Yang; Jong Bin Kim; Seo-Young Park; Won Seo Park; Yeo-Kyu Youn

doi:10.4174/astr.2021.100.3.127

Selective inhibition of V600E-mutant BRAF gene induces apoptosis in thyroid carcinoma cell lines

Ann Surg Treat Res. 2021 Mar;100(3):127-136. doi: 10.4174/astr.2021.100.3.127. Epub 2021 Feb 26.

Authors

Kyoung Sik Park^{1

2

3}, Madhuri Saindane^{1

2}, Eun Yeol Yang¹, TongYi Jin³, Harikrishna Reddy Rallabandi^{1

2}, Alexander Heil⁴, Sang Eun Nam^{1

2}, Young Bum Yoo^{1

2}, Jung-Hyun Yang^{1

2}, Jong Bin Kim⁵, Seo-Young Park⁶, Won Seo Park⁷, Yeo-Kyu Youn⁸

Affiliations

¹ Department of Surgery, Konkuk University School of Medicine, Seoul, Korea.
² Department of Surgery, Konkuk University Medical Center, Seoul, Korea.
³ Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea.
⁴ Institute of Botany and Molecular Genetics, RWTH, Aachen University, Aachen, Germany.
⁵ Research Centers for Cellular Homeostasis, Ewha Womans University, Seoul, Korea.
⁶ Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
⁷ Department of Surgery, School of Medicine, Kyung Hee University, Seoul, Korea.
⁸ Thyroid Clinic, St. Peter's Hospital, Seoul, Korea.

Abstract

Purpose: Papillary thyroid cancer (PTC) has a high incidence of BRAF^V600E mutation. The purpose of this study was to evaluate the potential relationship between thyroiditis and BRAF^V600E mutation status in patients with PTC. We investigated how a selective inhibitor of BRAF^V600E PLX4032 affects the proliferation and inflammatory cytokine levels of thyroid cancer.

Methods: Two thyroid cancer cell lines TPC1 and 8505C were treated with PLX4032, an analysis was done on cell growth, cell cycle, the degree of apoptosis, and levels of inflammatory cytokines. To identify the functional links of BRAF, we used the STRING database.

Results: Docking results illustrated PLX4032 blocked the kinase activity by exclusively binding on the serine/threonine kinase domain. STRING results indicated BRAF is functionally linked to mitogen-activated protein kinase. Both cell lines showed a dose-dependent reduction in growth rate but had a different half maximal inhibitory concentration value for PLX4032. The reaction to PLX4032 was more sensitive in the 8505C cells than in the TPC1 cells. PLX4032 induced a G2/M phase arrest in the TPC1 cells and G0/G1 in the 8505C cells. PLX4032 induced apoptosis only in the 8505C cells. With PLX4032, the TPC1 cells showed decreased levels of vascular endothelial growth factor, granulocyte-macrophage colony-stimulating factor, chemokine (C-C motif) ligand 2/monocyte chemoattractant protein 1, whereas the 8505C cells showed significantly decreased levels of IL-8, serpin E1/plasminogen activator inhibitor-1, and matrix metalloproteinase (MMP)-3.

Conclusion: PLX4032 was cytotoxic in both TPC1 and 8505C cells and induced apoptosis. In the 8505C cells, inflammatory cytokines such as IL-8 and MMP-3 were down-regulated. These findings suggest the possibility that the BRAF^V600E mutation needs to target inflammatory signaling pathways in the treatment of thyroid cancer.

Keywords: BRAFV600E; Cytokines; Thyroid neoplasms; Vemurafenib.