High expression of apolipoprotein C1 promotes proliferation and inhibits apoptosis of papillary thyroid carcinoma cells by activating the JAK2/STAT3 signaling pathway

doi:10.12122/j.issn.1673-4254.2025.02.17

Abstract

Abstract:

Objective To investigate the expression of apolipoprotein C1 (APOC1) in papillary thyroid carcinoma (PTC) and its effects on proliferation and apoptosis of PTC cells. Methods The expression level of APOC1 in PTC and its impact on prognosis were analyzed using GEPIA 2 and Kaplan-Meier databases. Immunohistochemistry (IHC) and Western blotting were used to detect the expression of APOC1 in PTC and adjacent tissues and in 3 PTC cell lines and normal thyroid Nthyori 3-1 cells. In TPC-1 and BCPAP cells, the effect of Lipofectamine 2000-mediated transfection with APOC1 siRNA or an APOC1-overexpressing plasmid on cell growth and colony formation ability were examined by observing the growth curves and using colony-forming assay. The changes in cell cycle and apoptosis of the transfected cells were analyzed with flow cytometry. RT-qPCR and Western blotting were used to detect the changes in expressions of P21, P27, CDK4, cyclin D1, Bcl-2, Bax, caspase-3 and caspase-9 and the key proteins in the JAK2/STAT3 signaling pathway. Results APOC1 expression was significantly higher in PTC tissues and the 3 PTC cell lines than in the adjacent tissues and Nthyori 3-1 cells, respectively. In TPC-1 and BCPAP cells, APOC1 knockdown obviously reduced cell proliferative activity, increased the percentage of G0/G1 phase cells, lowered the percentages of S and G2 phase cells, promoted cell apoptosis, and downregulated mRNA and protein expression levels of CDK4, cyclin D1 and Bcl-2 and the protein levels of p-JAK2 and p-STAT3. APOC1 overexpression in the cells produced the opposite effects on cell proliferation, apoptosis, cell cycle and the mRNA and protein expressions. The application of AG490, a JAK2 inhibitor, strongly attenuated APOC1 overexpression-induced activation of the JAK2/STAT3 signaling pathway in BCPAP cells. Conclusion APOC1 overexpression promotes proliferation and inhibits apoptosis of PTC cells possibly by activating the JAK2/STAT3 signaling pathway and accelerating cell cycle progression.

Key words: papillary thyroid carcinoma, apolipoprotein C1, proliferation, apoptosis, JAK2/STAT3 signaling pathway

Yu BIN, Ziwen LI, Suwei ZUO, Sinuo SUN, Min LI, Jiayin SONG, Xu LIN, Gang XUE, Jingfang WU. High expression of apolipoprotein C1 promotes proliferation and inhibits apoptosis of papillary thyroid carcinoma cells by activating the JAK2/STAT3 signaling pathway[J]. Journal of Southern Medical University, 2025, 45(2): 359-370.

Figures/Tables 14

Tab.1 Primer sequences for RT-qPCR

Gene	Sequence
APOC1	F:5'-CTGGTGGTGGTTCTGTCGAT-3'
	R:5'-TCACTCTGTTTGATGCGGCT-3'
β-actin	F:5'-CCTGGGCATGGAGTCCTGTG-3'
	R:5'-AGGGGCCGGACTCGTCATAC-3'

Fig.1 Bioinformatic analysis of APOC1 expression in PTC and Adjacent tissues. A: Analysis of expression levels of APOC1 in PTC tissues and adjacent tissues using GEPIA 2 database (*P<0.05). B, C: Analysis of the relationship between APOC1 mRNA expression and patient prognosis using Kaplan-Meier database.

Fig.2 Expression of APOC1 in clinical samples of PTC and adjacent tissues. A: Western blotting for detecting APOC1 expression in PTC tissues and adjacent tissues. B: Quantitative analysis of expression level. ***P<0.001 vs adjacent tissue.

Fig.3 Immunohistochemical detection of APOC1 expression in PTC and Adjacent tissue. A: APOC1 positive signal in PTC tissue (brown) in the cytoplasm. B: Negative expression of APOC1 in adjacent tissue.

Fig.4 Immunocytochemical detection of APOC1 protein in TPC-1, K1, BCPAP and Nthyori 3-1 cells. A: Negative expression of APOC1 in normal thyiod follicular epithelial Nthyori 3-1 cells. B-D: Positive signals of APOC1 in the 3 PTC cell lines located in the cytoplasm.

Fig.5 Western blotting and RT-qPCR for detecting APOC1 expression in K1, TPC-1, BCPAP and Nthyori 3-1 cells. A,B: Expression levels of APOC1 protein in different cell lines detected by Western blotting. C: Expression levels of APOC1 mRNA in different cell lines. ***P<0.001, ****P<0.0001 vs Nthyori 3-1 cells (n=3).

Fig.6 Expression of APOC1 protein and mRNA in TPC-1 cells with APOC1 knockdown. A,B: Expression levels of APOC1 protein in TPC-1 cells with APOC1 knockdown detected by Western blotting. C: Expression levels of APOC1 mRNA in TPC-1 cells with APOC1 knockdown. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001 vs shRNAC (n=3).

Fig.7 Decreased APOC1 expressions at both protein and mRNA levels in TPC-1 cells with APOC1 knockdown. A, B: Expression levels of APOC1 protein in shRNAC group, shRNA1 group, and shRNA2 group. C: Expression levels of APOC1 mRNA in the shRNAC group, shRNA1 group, and shRNA2 group. *P<0.05, **P<0.01, ***P<0.001 vs shRNAC (n=3).

Fig.8 Increased APOC1 protein and mRNA levels in BCPAP cells with APOC1 overexpression. A, B: Expression levels of APOC1 protein in OENC and OE groups. C: Expression levels of APOC1 mRNA in OENC and OE groups. **P<0.01, ****P<0.0001 vs OENC (n=3).

Fig.9 Effect of APOC1 knockdown and overexpresison on PTC cell proliferation. A, C: Colony formation assay of the transfected cells. B,D: Number of cell clusters in the transfected cells. E,G: Growth curves of the transfected cells. F,H: Cell confluence of the transfected cells. *P<0.05,**P<0.01,***P<0.001, ****P<0.001 vs shRNAC/OENC (n=3).

Fig.10 Effect of APOC1 knockdown and overexpresison on cell cycle. A, C: Cell cycle diagrams of the cells with APOC1 knockdown and overexpresison. B, D: Analysis of cell cycle percentage. *P<0.05, **P<0.01, ***P<0.001 vs shRNAC/OENC (n=3).

Fig.11 Effect of APOC1 knockdown and overexpresison on cell apoptosis. A,C: Cell apoptosis maps of cells with APOC1 knockdown and overexpresison. B,D: Percentages of apoptotic cells each group.**P<0.01, ***P<0.001 vs shRNAC/OENC (n=3).

Fig.12 Effect of APOC1 knockdown and overexpresison on expresisons of cell cycle and apoptosis-related proteins and their mRNA levels. A-C: Cell cycle-related protein and mRNA expression levels of in cells with APOC1 knockdown. D-F: Cell cycle-related protein and mRNA expression levels in APOC1 knockdown group. G-I: Apoptosis-related protein and mRNA expression levels in APOC1 overexpression group. J-L: Apoptosis-related protein and mRNA expression levels in APOC1 knockdown group. *P<0.05, **P<0.01,***P<0.001, ****P<0.0001 vs shRNAC/OENC (n=3).

Fig.13 APOC1 knockdown and overexpresison on expressions of key proteins in the JAK2/STAT3 signaling pathway detected by Western blotting. A,B: Expression levels of key proteins in the JAK2/STAT3 signaling pathway in APOC1 knockdown group. C,D: Expression levels of key proteins in the JAK2/STAT3 signaling pathway in APOC1 overexpression group. **P<0.01, ***P<0.001, ****P<0.0001 vs shRNAC/OENC (n=3).

References 42

1	陈一峰, 郑泽荣, 林进吉, 等. 甲状腺乳头状癌合并滤泡癌10例临床病理分析[J]. 临床与实验病理学杂志, 2020, 36(4): 464-6.
2	Li R, Zhang YJ, Xiang RQ, et al. Analysis of the mechanism of maslinic acid on papillary thyroid carcinoma based on RNA-seq technology[J]. Evid Based Complement Alternat Med, 2022, 2022: 7000531.
3	Jong MC, Hofker MH, Havekes LM. Role of ApoCs in lipoprotein metabolism: functional differences between ApoC1, ApoC2, and ApoC3[J]. Arterioscler Thromb Vasc Biol, 1999, 19(3): 472-84.
4	Fuior EV, Gafencu AV. Apolipoprotein C1: its pleiotropic effects in lipid metabolism and beyond[J]. Int J Mol Sci, 2019, 20(23): 5939.
5	Zhou XP, Chen Y, Mok KY, et al. Non-coding variability at the APOE locus contributes to the Alzheimer's risk[J]. Nat Commun, 2019, 10(1): 3310.
6	Cao XY, Wu BQ, Guo SM, et al. APOC1 predicts a worse prognosis for esophageal squamous cell carcinoma and is associated with tumor immune infiltration during tumorigenesis[J]. Pathol Oncol Res, 2023, 29: 1610976.
7	Mei LH, Long J, Wu SE, et al. APOC1 reduced anti-PD-1 immunotherapy of nonsmall cell lung cancer via the transformation of M2 into M1 macrophages by ferroptosis by NRF2/HO-1[J]. Anticancer Drugs, 2024, 35(4): 333-43.
8	Hao XP, Zheng ZY, Liu HY, et al. Inhibition of APOC1 promotes the transformation of M2 into M1 macrophages via the ferroptosis pathway and enhances anti-PD1 immunotherapy in hepatocellular carcinoma based on single-cell RNA sequencing[J]. Redox Biol, 2022, 56: 102463.
9	Jiang H, Tang JY, Xue D, et al. Apolipoprotein C1 stimulates the malignant process of renal cell carcinoma via the Wnt3a signaling[J]. Cancer Cell Int, 2021, 21(1): 41.
10	Yang SM, Du JX, Wang W, et al. APOC1 is a prognostic biomarker associated with M2 macrophages in ovarian cancer[J]. BMC Cancer, 2024, 24(1): 364.
11	Ren H, Chen ZH, Yang L, et al. Apolipoprotein C1 (APOC1) promotes tumor progression via MAPK signaling pathways in colorectal cancer[J]. Cancer Manag Res, 2019, 11: 4917-30.
12	Yi J, Ren LW, Wu J, et al. Apolipoprotein C1 (APOC1) as a novel diagnostic and prognostic biomarker for gastric cancer[J]. Ann Transl Med, 2019, 7(16): 380.
13	Yan Y, Zhou YH, Wang K, et al. Apolipoprotein C1 (APOC1), A candidate diagnostic serum biomarker for breast cancer identified by serum proteomics study[J]. Crit Rev Eukaryot Gene Expr, 2022, 32(4): 1-9.
14	Lei B, Qian L, Zhang YP, et al. MLAA-34 knockdown shows enhanced antitumor activity via JAK2/STAT3 signaling pathway in acute monocytic leukemia[J]. J Cancer, 2020, 11(23): 6768-81.
15	李超友, 罗亚星, 孙新民, 等. 载脂蛋白C1在甲状腺乳头状癌中的临床表达及生物信息学分析[J]. 中国耳鼻咽喉颅底外科杂志, 2021, 27(4): 445-51.
16	王培宇, 黄祺, 王少东, 等. 《全球癌症统计数据2022》要点解读[J]. 中国胸心血管外科临床杂志, 2024, 31(7): 933-54.
17	Miranda-Filho A, Lortet-Tieulent J, Bray F, et al. Thyroid cancer incidence trends by histology in 25 countries: a population-based study[J]. Lancet Diabetes Endocrinol, 2021, 9(4): 225-34.
18	Vaccarella S, Franceschi S, Bray F, et al. Worldwide thyroid-cancer epidemic? the increasing impact of overdiagnosis[J]. N Engl J Med, 2016, 375(7): 614-7.
19	Li MM, Meheus F, Polazzi S, et al. The economic cost of thyroid cancer in France and the corresponding share associated with treatment of overdiagnosed cases[J]. Value Health, 2023, 26(8): 1175-82.
20	Ishijima T, Nakajima K. Mechanisms of microglia proliferation in a rat model of facial nerve anatomy[J]. Biology, 2023, 12(8): 1121.
21	Cai ZJ, Wang JR, Li YD, et al. Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors[J]. Sci China Life Sci, 2023, 66(1): 94-109.
22	Coqueret O. New roles for p21 and p27 cell-cycle inhibitors: a function for each cell compartment[J]? Trends Cell Biol, 2003, 13(2): 65-70.
23	王钦磊. APOC1通过Wnt/β-catenin信号通路诱导G0/G1期阻滞抑制胆管癌细胞增殖的机制研究[D]. 青岛: 青岛大学, 2024.
24	Pu HC, Qian Q, Wang FL, et al. Schizandrin A induces the apoptosis and suppresses the proliferation, invasion and migration of gastric cancer cells by activating endoplasmic reticulum stress[J]. Mol Med Rep, 2021, 24(5): 787.
25	Zhang Y, Yang X, Ge XH, et al. Puerarin attenuates neurological deficits via Bcl-2/Bax/cleaved caspase-3 and Sirt3/SOD2 apoptotic pathways in subarachnoid hemorrhage mice[J]. Biomed Pharmacother, 2019, 109: 726-33.
26	Guan HM, Li WQ, Liu J, et al. LncRNA HIF1A-AS2 modulated by HPV16 E6 regulates apoptosis of cervical cancer cells via P53/caspase9/caspase3 axis[J]. Cell Signal, 2022, 97: 110390.
27	Takano S, Yoshitomi H, Togawa A, et al. Apolipoprotein C-1 maintains cell survival by preventing from apoptosis in pancreatic cancer cells[J]. Oncogene, 2008, 27(20): 2810-22.
28	宋慧娟, 徐振华, 何东宁. 载脂蛋白C1表达对人肝癌HepG2细胞增殖和凋亡的影响及其机制[J]. 吉林大学学报: 医学版, 2024, 50(1): 128-35.
29	Li RJ, He HX, He XX. APOC1 promotes the progression of osteosarcoma by binding to MTCH2[J]. Exp Ther Med, 2023, 25(4): 163.
30	余以珊. APOC1通过MAPK/ERK通路促进食管鳞状细胞癌增殖及转移的机制研究[D]. 济南: 山东大学, 2023.
31	Gao FF, Chen JL, Zhang TT, et al. LPCAT1 functions as an oncogene in cervical cancer through mediating JAK2/STAT3 signaling[J]. Exp Cell Res, 2022, 421(1): 113360.
32	Judd LM, Menheniott TR, Ling H, et al. Inhibition of the JAK2/STAT3 pathway reduces gastric cancer growth in vitro and in vivo [J]. PLoS One, 2014, 9(5): e95993.
33	Fu LX, Lian QW, Pan JD, et al. JAK2 tyrosine kinase inhibitor AG490 suppresses cell growth and invasion of gallbladder cancer cells via inhibition of JAK2/STAT3 signaling[J]. J Biol Regul Homeost Agents, 2017, 31(1): 51-8.
34	Brooks AJ, Putoczki T. JAK-STAT signalling pathway in cancer[J]. Cancers, 2020, 12(7): 1971.
35	Xing ZY, Wang X, Liu JQ, et al. Effect of miR-210 on the chemosensitivity of breast cancer by regulating JAK-STAT signaling pathway[J]. Biomed Res Int, 2021, 2021: 7703159.
36	Cheng X, PKKYeung, Zhong K, et al. Astrocytic endothelin-1 overexpression promotes neural progenitor cells proliferation and differentiation into astrocytes via the Jak2/Stat3 pathway after stroke[J]. J Neuroinflammation, 2019, 16(1): 227.
37	Yin Z, Ma TT, Lin Y, et al. IL-6/STAT3 pathway intermediates M1/M2 macrophage polarization during the development of hepatocellular carcinoma[J]. J Cell Biochem, 2018, 119(11): 9419-32.
38	Kim MS, Lee WS, Jeong J, et al. Induction of metastatic potential by TrkB via activation of IL6/JAK2/STAT3 and PI3K/AKT signaling in breast cancer[J]. Oncotarget, 2015, 6(37): 40158-71.
39	Zhou JM, Wu A, Yu XT, et al. SIRT6 inhibits growth of gastric cancer by inhibiting JAK2/STAT3 pathway[J]. Oncol Rep, 2017, 38(2): 1059-66.
40	Carpenter RL, Lo HW. STAT3 target genes relevant to human cancers[J]. Cancers, 2014, 6(2): 897-925.
41	Wang JQ, Zhang Y, Song H, et al. The circular RNA circSPARC enhances the migration and proliferation of colorectal cancer by regulating the JAK/STAT pathway[J]. Mol Cancer, 2021, 20(1): 81.
42	Li YJ, Wei J, Sun Y, et al. DLGAP5 regulates the proliferation, migration, invasion, and cell cycle of breast cancer cells via the JAK2/STAT3 signaling axis[J]. Int J Mol Sci, 2023, 24(21): 15819.

[1]	Xiaoyu CHANG, Hanwen ZHANG, Hongting CAO, Ling HOU, Xin MENG, Hong TAO, Yan LUO, Guanghua LI. Heat stress affects expression levels of circadian clock gene Bmal1 and cyclins in rat thoracic aortic endothelial cells [J]. Journal of Southern Medical University, 2025, 45(7): 1353-1362.
[2]	Ting XIE, Yunyun WANG, Ting GUO, Chunhua YUAN. The peptide toxin components and nucleotide metabolites in Macrothele raveni venom synergistically inhibit cancer cell proliferation by activating the pro-apoptotic pathways [J]. Journal of Southern Medical University, 2025, 45(7): 1460-1470.
[3]	Yujia YANG, Lifang YANG, Yaling WU, Zhaoda DUAN, Chunze YU, Chunyun WU, Jianyun YU, Li YANG. Cannabidiol inhibits neuronal endoplasmic reticulum stress and apoptosis in rats with multiple concussions by regulating the PERK-eIF2α-ATF4-CHOP pathway [J]. Journal of Southern Medical University, 2025, 45(6): 1240-1250.
[4]	Yumei ZENG, Jike LI, Zhongxi HUANG, Yibo ZHOU. Villin-like protein VILL suppresses proliferation of nasopharyngeal carcinoma cells by interacting with LMO7 protein [J]. Journal of Southern Medical University, 2025, 45(5): 954-961.
[5]	Yue CHEN, Linyu XIAO, Lü REN, Xue SONG, Jing LI, Jianguo HU. Monotropein improves motor function of mice with spinal cord injury by inhibiting the PI3K/AKT signaling pathway to suppress neuronal apoptosis [J]. Journal of Southern Medical University, 2025, 45(4): 774-784.
[6]	Fei CHU, Xiaohua CHEN, Bowen SONG, Jingjing YANG, Lugen ZUO. Moslosooflavone ameliorates dextran sulfate sodium-induced colitis in mice by suppressing intestinal epithelium apoptosis via inhibiting the PI3K/AKT signaling pathway [J]. Journal of Southern Medical University, 2025, 45(4): 819-828.
[7]	Yaqing YUE, Zhaoxia MU, Xibo WANG, Yan LIU. Aurora-A overexpression promotes cervical cancer cell invasion and metastasis by activating the NF-κBp65/ARPC4 signaling axis [J]. Journal of Southern Medical University, 2025, 45(4): 837-843.
[8]	Yi ZHANG, Yu SHEN, Zhiqiang WAN, Song TAO, Yakui LIU, Shuanhu WANG. High expression of CDKN3 promotes migration and invasion of gastric cancer cells by regulating the p53/NF-κB signaling pathway and inhibiting cell apoptosis [J]. Journal of Southern Medical University, 2025, 45(4): 853-861.
[9]	Shunjie QING, Zhiyong SHEN. High expression of hexokinase 2 promotes proliferation, migration and invasion of colorectal cancer cells by activating the JAK/STAT pathway and regulating tumor immune microenvironment [J]. Journal of Southern Medical University, 2025, 45(3): 542-553.
[10]	Qingqing HUANG, Wenjing ZHANG, Xiaofeng ZHANG, Lian WANG, Xue SONG, Zhijun GENG, Lugen ZUO, Yueyue WANG, Jing LI, Jianguo HU. High MYO1B expression promotes proliferation, migration and invasion of gastric cancer cells and is associated with poor patient prognosis [J]. Journal of Southern Medical University, 2025, 45(3): 622-631.
[11]	Di CHEN, Ying LÜ, Yixin GUO, Yirong ZHANG, Ruixuan WANG, Xiaoruo ZHOU, Yuxin CHEN, Xiaohui WU. Dihydroartemisinin enhances doxorubicin-induced apoptosis of triple negative breast cancer cells by negatively regulating the STAT3/HIF-1α pathway [J]. Journal of Southern Medical University, 2025, 45(2): 254-260.
[12]	Jinhua ZOU, Hui WANG, Dongyan ZHANG. SLC1A5 overexpression accelerates progression of hepatocellular carcinoma by promoting M2 polarization of macrophages [J]. Journal of Southern Medical University, 2025, 45(2): 269-284.
[13]	Zhoufang CAO, Yuan WANG, Mengna WANG, Yue SUN, Feifei LIU. LINC00837/miR-671-5p/SERPINE2 functional axis promotes pathological processes of fibroblast-like synovial cells in rheumatoid arthritis [J]. Journal of Southern Medical University, 2025, 45(2): 371-378.
[14]	Xiaohua CHEN, Hui LU, Ziliang WANG, Lian WANG, Yongsheng XIA, Zhijun GENG, Xiaofeng ZHANG, Xue SONG, Yueyue WANG, Jing LI, Jianguo HU, Lugen ZUO. Role of Abelson interactor 2 in progression and prognosis of gastric cancer and its regulatory mechanisms [J]. Journal of Southern Medical University, 2024, 44(9): 1653-1661.
[15]	Liangjun XUE, Qiuyu TAN, Jingwen XU, Lu FENG, Wenjin LI, Liang YAN, Yulei LI. MiR-6838-5p overexpression inhibits proliferation of breast cancer MCF-7 cells by downregulating DDR1 expression [J]. Journal of Southern Medical University, 2024, 44(9): 1677-1684.